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BAROMETRIC PRESSURE
PAUL BERT
Born October 17, 1833. Died November 11. 1886.
BAROMETRIC PRESSURE
Researches In Experimental Physiology
PAUL BERT
Translated from the French by
MARY ALICE HITCHCOCK, M.A.
Formerly Professor of Romance Languages at the
University of Akron
and
FRED A. HITCHCOCK, Ph.D.
Associate Professor of Physiology at
The Ohio State University
0 I.
COLLEGE BOOK COMPANY
COLUMBUS, OHIO
1943
Copyright 1943
By
COLLEGE BOOK COMPANY
F. C. Long, Proprietor
THE F. J. HEER PRINTING COMPANY
Columbus, Ohio
1943
FOREWORD
It can be said of Paul Bert as it has been of Vesalius, Harvey
and Boyle, that the full significance of his work could not be fully
appreciated until long after his death; but it is tragic that the chaos
of a far-flung war was required to bring Bert's work into its full
meaning and perspective. At a time when altitude physiologists
and flight surgeons are being feverishly trained by all countries at
war, it becomes of first importance to English-speaking peoples that
the great classic of altitude physiology should be made available
in the English language. Copies of the original French edition are
exceedingly rare, and one therefore cannot praise too warmly the
industry of Professor and Mrs. Hitchcock in preparing the English
rendering, and the patriotic foresight of the publishers in thus mak-
ing the text available to the flying personnel of our Armed Forces.
That such a task could be accomplished in the midst of war is of
itself gratifying, for it bears evidence that our perspectives and our
scholarly traditions are being maintained and will survive during
these years of stress and fury. As Professor Sigerist recently re-
marked in reviewing Howard Adelmann's translation of Fabricius,
"Today when everyone thinks in military terms I would like to
stress that the publication of such a book at such a time also repre-
sents a victory equally important to the capture of a strategic
hill and more endurable. One can have full confidence in the fu-
ture of a nation which in the midst of a bloody war possesses the
intellectual and technical resources to produce such a document of
scholarship."
The details of Bert's life are not widely known and it seems ap-
propriate here to give a brief sketch of his meteoric career. Among
his contemporaries Bert was probably better known for his pioneer
studies on skin grafting — work that did much toward fostering the
specialty of plastic surgery during the war of 1870 — than he was
for his studies in altitude physiology. Indeed in a notice published
in the Lancet on November 20, 1886, shortly after his death, there is
no mention of La pression barometrique and little to suggest that
Bert was a great physiologist.
Born at Auxerre on October 17, 1833, Paul Bert received his
early education in the Department of Yonne. He had chosen en-
gineering for his profession and had entered the College de St.
Barbe with a view to preparing for the polytechnic school. He was
dissuaded from this in favor of the law and passed his bar exam-
inations successfully. But he soon found the law boring to his
inquisitive mind and, for the third time, modified his course of
study on becoming acquainted with Gratiolet, the Director of the
Anatomical Museum in Paris. He eventually obtained his M.D.
degree in 1863 at the age of thirty. During his years at Paris he
had come under the influence of Claude Bernard in whose labora-
tory he served as an assistant. Bernard recognized his ingenious
mind and predicted a brilliant future. His thesis, published in
1866, on the grafting of animal tissues, attracted wide notice, and
it won for Bert in 1865 the prize in experimental physiology offered
by the Academie des Sciences. After teaching zoology for several
years at the Faculte des Sciences at Bordeaux, he was appointed in
December 1869 as Bernard's successor to the Chair of Physiology
at the Faculte des Sciences at Paris. Bernard at the time occupied
two chairs, one at the Sorbonne, the other at the Faculte, and he
resigned the latter to make place for his brilliant pupil.
During the last two years of the Second Empire, Paul Bert made
himself conspicuous in the political world by his uncompromising
republicanism and at the fall of the Napoleonic dynasty in 1870, he
was rewarded by Gambetta with the Prefecture du Nord. Elected
Deputy in 1871, he became noted for his constant opposition to re-
ligious congregation, which led eventually to the decrees of expul-
sion against the Jesuits, Dominicans and other orders. He was in-
sistent that the state schools should be taught not by nuns and
friars, but by non-sectarian personnel. In 1881 he was made Min-
ister of Public Instruction in Gambetta's famous Grand Ministere,
but he fell with his chief after an ephemeral exercise of power.
Following the death of Gambetta, Bert's political influence was
on the wane and he returned to his scientific pursuits, obtaining a
vacant chair in the Academie des Sciences. At the beginning of the
year, the attention of the French Government was forcibly drawn
to the highly unsatisfactory state of affairs in French Indo-China's
Province of Tongking, and it decided to send out a Resident Gen-
eral vested with special powers to effect a thorough reorganization.
VI
Paul Bert was chosen for the post since he had always supported
the French colonial policy, and he departed for the East in Febru-
ary, 1886. He was enormously active during his first five months at
Hanoi and did much to effect a complete reorganization of the Tong-
king government; but in November he became suddenly ill and died
of dysentery on November 11th, at the early age of fifty-three.
Paul Bert's activities had turned to altitude physiology about
1869 as a result of his friendship with a Dr. Jourdanet who had be-
come interested in mountain sickness through personal experience
while travelling in Mexico. Jourdanet was a wealthy patron of the
arts and sciences, and he gave Bert the essential financial support
for altitude studies, making it possible for him to develop several
low-pressure chambers for man and animal. In the course of his
investigations, Bert had sponsored an ascent in a balloon, Zenith,
in which various determinations were to be made of the constitu-
tion of the upper air (April 15, 1875) . This ill-fated expedition was
undertaken by three balloon enthusiasts, MM. Sivel, Croce-Spinelli,
and the only survivor of the expedition, Gaston Tissandier. The ac-
count of the trip may be given in Tissandier 's words:
"I now come to the fateful moments when we were overcome by the
terrible action of reduced pressure. At 22,900 feet . . . torpor had seized
me. I wrote nevertheless . . . though I have no clear recollection of writ-
ing. We are rising. Croce is panting. Sivel shuts his eyes. Croce also
shuts his eyes. ... At 24,600 feet the condition of torpor that overcomes
one is extraordinary. Body and mind become feebler. . . . There is no
suffering. On the contrary, one feels an inward joy. There is no thought
of the dangerous position; one rises and is glad to be rising. I soon felt
myself so weak that I could not even turn my head to look at my com-
panions. ... I wished to call out that we were now at 26,000 feet, but my
tongue was paralyzed. All at once I shut my eyes and fell down powerless
and lost all further memory."
The fatalities on the Zenith were due, in some measure, to com-
petitive braggadocio, for the English balloonist, Glaisher, in 1862
had ascended to 24,000 feet and the Tissandier expedition wished to
outdo him. They had little notion of the dangers, nor were they
aware of the peril of the fixation of ideas that develops under low
oxygen tension.
Paul Bert began to work actively on respiratory problems early
in the seventies, and in 1874 published a preliminary monograph of
167 pages entitled: Recherches expcrimentales sur Vinfluence que les
modifications dans la pression barometrique exercent sur les phcno-
mcnes de la vie. This is taken up in part with a description of his
admirably constructed low-pressure chamber. In 1878 he published
VII
the book here translated which has become one of the great land-
marks of physiology — a book which stands as the very cornerstone
of modern altitude physiology, La pression baromctrique. Re-
cherches de physiologie expcrimentale , containing 1178 pages and
89 text figures. The first 522 pages deal with the history of altitude
physiology up to that date; and if Paul Bert did nothing else, we
should be lastingly in his debt for this masterly historical presenta-
tion— a model, be it said, for any student wishing to write in the
field of medical history. The second part, occupying 518 pages, con-
tains experimental protocols; the third and final part, which runs to
118 pages, contains his resume and conclusions, and is again a model
of concise, orderly and logical scientific presentation.
What precisely did Bert prove? There had been sharp diver-
gence of opinion whether mountain sickness was due to diminution
of barometric pressure per se, or to diminution of oxygen pressure.
Bert performed critical experiments, keeping the absolute pressure
of oxygen constant while lowering the total atmospheric pressure,
repeating them time and again both in animals and man. By so
doing he proved beyond all doubt that the principal symptoms of
altitude sickness arise from reduced partial pressure of oxygen and
not from diminution of total pressure. He thus applied for the first
time to human respiration Dalton's concept of partial pressure
which has become the basis of all subsequent work in the field of
altitude physiology.
In one of his vivid lectures on the history of physiology, Sir
Michael Foster said that science travels in circles: the concept fol-
lowed yesterday may be dropped today and rediscovered tomor-
row. One of those who did not accept Paul Bert's conclusions was
that picturesque physiologist of Italy, Angelo Mosso, who main-
tained that at altitude one breathed so deeply that carbonic acid
was lost with resulting alkalosis, and that oxygen-want played
only a small part in mountain sickness, the major symptoms be-
ing due to "acapnia"— loss of carbon dioxide. Few in this century,
save Yandell Henderson, have paid due attention to Mosso and
acapnia, but we are coming once again to heed what he said. More
is known now about acid-base relationships in blood and tissues.
The carotid sinus reflexes have also been discovered. When blood
of low oxygen saturation reaches the carotid sinus, a reflex in-
crease in depth and frequency of respiration occurs. The partial
pressure of oxygen is a primary and determining stimulus as Bert
maintained; but under conditions of low oxygen tension, hyper-
ventilation of serious proportions may occur, and we have reason
VIII
to believe that pilots in the higher altitude ranges may in some
circumstances hyperventilate to such an extent as to bring on
tetany and even loss of consciousness.
Thus the pendulum swings; and if we wish to gain perspective
for tomorrow, we look to the past and to the work of men like
Robert Boyle, Paul Bert and Angelo Mosso who give us courage
and inspiration to face the future.
John F. Fulton.
Yale University,
August 15, 1943.
IX
TRANSLATORS' NOTE
In his preface Paul Bert comments on his use of direct quota-
tions in the historical part of this book in the following words, "In
my bibliographic research I have repeatedly seen the affirmations
of an author changed to negations by a series of translations and
analyses." Again in a footnote on Chapter II he calls attention to
the fact that a passage which he quotes from the French translation
of the account of the balloon flights of Glaisher and Coxwell did not
occur in the English text and adds, "Can it have been added by a
fanciful translator? Traduttore, traditore" (translator, traitor).
This evident distrust of our author for translators has been con-
stantly in our minds and our translation is, therefore, somewhat
more literal than it might otherwise have been. This policy has
resulted in the use of certain words and expressions that are old
fashioned; for example, we have used the word hematosis to mean
arterialization of blood and we have retained the expression car-
bonic acid, even where our author is obviously referring to carbon
dioxide.
In only two respects have we departed from the plan followed
in the French edition. First, the footnotes, instead of being placed
at the bottom of the page on which the reference occurs, have been
grouped together and put at the end of the several chapters. This
method is made mandatory by the mechanics of modern type set-
ting, and also greatly improves the appearance of the page. Second,
we have added an index. In the French edition there was no index
and the detailed table of contents together with the list of illustra-
tions was placed at the end of the book. In the English edition these
have been moved to the front of the book and the index put at the
end.
We wish to acknowledge our indebtedness and express our grati-
tude to the John Crerar Library of Chicago for the uninterrupted
use of a copy of the original French edition of La Pression Baro-
metrique over a period of more than two years. Copies of the book
XI
were also loaned us for shorter periods by the Library of Congress
and by the Aero-Medical Laboratory at Wright Field. Photographic
copies of the illustrations in the original edition from which the
plates for the present volume were prepared were furnished us by
the staff of the Wright Field Aero-Medical Laboratory. We are
grateful to Colonel Otis O. Benson, Jr., who arranged to have this
done.
Various agencies of the Ohio State University were of consider-
able assistance in a number of ways. Funds to help defray the cost
of clerical assistance were furnished by President Bevis, and by
the Graduate School upon the recommendation of Dean Alpheus
Smith. The staff of the library furnished assistance whenever
called upon, and Mr. Oscar Thomas and Mr. John B. Fullen of the
Alumni Office were of great assistance in a variety of ways; we are
especially grateful to them both.
Finally, we want to thank Professor John F. Fulton of Yale
University not only for the preparation of the foreword, but also for
his enthusiastic support and valuable advice throughout the entire
project, and Mr. F. C. Long of the College Book Company, without
whose vision and faith in Paul Bert the publication of the complete
translation would have been impossible.
It is with some hesitation that we turn the manuscript over to
the printer. It contains errors and imperfections. Many of these
could be corrected by further revision, but such revision takes time
and in the present state of the world it seems desirable to make
Paul Bert's classic work available to the many English speaking
investigators in the field of aviation medicine with as little delay
as possible. We have therefore foregone further revision and polish-
ing. We know nothing would please Paul Bert more than the
knowledge that his work had been of use to the Allied Nations in
their struggle to free his beloved country from the shackles of its
traditional enemy. Paul Bert was a liberal, a humanitarian, and
a loyal patriot, as well as an outstanding scientist. During the
months that we have worked on the translation of his great book
our admiration and respect for him have grown. It is our sincere
hope that we have made none of his affirmations negations and
that we have been translators without being traitors.
M. A. H.
F. A. H.
XII
TO DOCTOR JOURDANET
My dear Colleague:
It is to you that I owe, not only the first idea of this
work, but also the material means to execute it, which
are so difficult to collect. I have been very happy to
see physiological experimentation on one of the most
important points of my study confirm entirely the
theory which your intelligence had deduced from nu-
merous pathological observations collected on the high
Mexican plateaux. For all these reasons I should dedi-
cate this book to you, and I do so with the greater
pleasure because you are one of those persons who
would make gratitude easy to even the most thankless
natures.
Paul Bert.
XIII
PREFACE
No one doubts the considerable influence which changes in baro-
metric pressure can exercise on living beings; we are even inclined
to exaggerate its importance. If the barometric column rises or
falls some millimeters, nervous or asthmatic people experience
favorable or painful symptoms which they attribute to the heavi-
ness or the lightness of the air. If this were really the cause, a
walk from the banks of the Seine to the top of the Butte Mont-
martre or the converse should produce similar results in the same
people.
But outside this group of data, to which I shall return in a mo-
ment, many remain which present a much greater interest, and
which deserve to be studied with perseverance.
Are we dealing with increase in pressure? When, in the shafts
of a mine or in the caissons intended to become the piers of a
bridge, workmen are protected against the invasion of the water
by air compressed by powerful machines to several atmospheres,
they experience strange and sometimes dangerous symptoms dur-
ing or after their stay in compressed air. Likewise divers who
gather pearls, sponges, or coral, or attempt the salvage of sunken
ships, furnished with diving apparatus and breathing an air whose
pressure is proportional to the depth they reach, are frequently
stricken by paralysis or death. On the other hand, medicine, mak-
ing use of observations that are already old, has attempted with
considerable success to make use of the influence of air at suitably
low pressures, since the time of Junod, Pravaz, and Tabarie.
Are we dealing with decrease in pressure? We can mention
first the symptoms which threaten aeronauts when their ascent
brings them to heights above 4000 meters: nausea, vertigo, hemor-
rhage, syncope; then the phenomena which have been known much
longer by all those who have attempted the ascent of mountains
of over 3000 to 4000 meters, mountain sickness, about whose cause
XV
so many strange hypotheses have been suggested. Finally we
find here data of a much greater importance. It is no longer a
matter of a few workmen, a few invalids, or a few tourists, but of
whole populations which normally and regularly live, construct
cities, group themselves as peoples, in these lofty places where
painful and sometimes unendurable sensations await the traveler.
We feel that here our problem affects not only the hygiene of
peoples, but also to a certain point, their history and politics. In
the Himalayas, in the Cordillera of the Andes, populous cities are
built at heights greater than that of our Mont-Blanc, where no one
completely escapes mountain sickness; in Mexico, thousands of
men live on the plateaux of Anahuac, at an average height of
2000 meters; the great civilizations of the Mayas and the Nahuas
had their maximum of development between 2000 and 4000 meters
above sea level.
The reader can see by this brief survey in what important
points the question affects the experimentation to which I have
conscientiously devoted myself. It will consequently seem natural
that such phenomena have given rise to numerous publications by
doctors or travelers; but he will no doubt be surprised that so little
has been attempted in laboratory experimentation to explain their
cause. The simplest idea apparently would have been to construct
apparatuses permitting one to reproduce changes in barometric
pressure, isolating them from secondary conditions, uncontrolled
variables, which inevitably accompany them in the state of nature,
and to examine the immediate results of these changes on man and
on animals. Now very little has been done in this direction. On
the other hand, we shall find incomplete observations, pretentious
dissertations, and probable or absurd explanations in great number.
My purpose has been to fill this considerable gap, and to solve
these important problems by a purely experimental method.
In taking my position thus on solid ground, I had to set
aside systematically three kinds of questions which could not be
attacked in the laboratory, and for which consequently absolute
conditions of proof could not be collected; that is: daily variations
of the barometer, therapeutic applications and acclimatization in
lofty places.
I do not regret the first question, which does not seem to me
even to belong to our subject of study. Slight modifications in air
pressure revealed by the barometric column in a given place are
accompanied by too many other meteorological phenomena (hygro-
metric, electric, etc.) for anyone to determine the part, certainly
very small, which they play in the condition of certain invalids.
XVI
\ ■
As to the other two questions, I have made great use of data
given by authors who have discussed these topics, and I think that
my own studies will not be without value in guiding physicians
and hygienists in the midst of the innumerable difficulties which
these questions involve. But I have not handled them directly, not
only because of my medical incompetence, not only because labora-
tory experiments on birds, dogs, or even men could hardly settle
them, but also for a special and rather personal reason.
Eight years ago, when Dr. Jourdanet, well known for his re-
markable studies on the climatology of Mexico and for his theory
of the anoxemia of altitudes, offered— with a generosity for which
I hope the results of my work might be worthy recompense— to
put at my disposal all the material means required by the re-
searches whose importance and difficulty I had publicly indicated x
in 1868, a sort of tacit agreement was established between us. I
was to limit myself to studying experimentally in the laboratory by
means of my instruments the modifications which changes in baro-
metric pressure would produce in the vital manifestations of ani-
mals or plants. Whatever the extent of my experimental equip-
ment, these changes evidently could not be of long duration, so
that if they were to produce convincing results, it was absolutely
necessary that they should be extensive. Besides, this is the pe-
culiar characteristic of laboratory experiments.
M. Jourdanet properly reserved for himself the study of the
effects produced by slight variations in barometric pressure, acting
either for a rather brief time upon invalids — a test the exquisite
delicacy of which will always terrify experimenters a little— or for
years upon the same individuals, or for centuries upon successive
generations, joining their effect to those of so many causes known
or unknown; dangerous problems, but very likely to fascinate a
wise and eager spirit, aided by an eloquent pen.
We both accomplished our tasks; two years ago, M. Jourdanet
published his fine book, Influence of Air Pressure on the Life of
Man: Altitude Climates and Mountain Climates.2
As for me, delayed by efforts outside the field of science, too
often called from my laboratory by important civic duties, it is
not until today that I present the properly arranged results of my
long researches.
The present book which, if I am not mistaken, holds interest not
only for physiologists, but also for physicians, engineers, and even
travelers, is divided into three parts: history, experiments, con-
clusions.
XVII
I have given the greatest pains to editing the history. I have
tried to collect all that has been written on the subject of my study.
It seemed to me that it would be very interesting for the reader to
have thus before him all the pieces of evidence, with infinite
variety of narration, frequent contradiction, and often instructive
repetitions. I thought it best to give the actual works of the authors
quoted: I distrusted even the most conscientious analyses; in my
bibliographic research I have repeatedly seen the affirmations of
an author changed to negation by a series of translations and anal-
yses. Besides, summarizing and analytical chapters rest the mind
of the reader; but each of the facts given there finds its proof in
the preceding extracts.
In the second part my personal experiments are recorded. The
titles of the chapters show the order in which I planned their
exposition. A glance at the table of contents indicates that after
studying directly the influence of changes in barometric pressure,
I have devoted a few chapters to new researches on the physio-
logical action of carbonic acid, on asphyxia, and on blood gases.
The reader will see in perusing these chapters that I have not
wandered as far from my subject as this mere statement of topics
might imply; the numerous references to this part of my book that
I make in my conclusions give evident proof of this fact.
In reporting my experiments, which number about 670, I have
used the enumerative method; all those which seem to me inter-
esting have been reported at length. This method has two advan-
tages: first, it furnishes proof of all the conclusions, and second, it
sometimes permits the reader to find in the account of the experi-
ments what the author did not see there himself. Summaries added
to each chapter facilitate rapid perusal of the results obtained.
Finally I call attention to the fact that on each point the experi-
ments are listed according to their date of performance; one can
thus take account of observations which escaped attention at the
beginning of the research, of improvements made by the experi-
menter, and consequently of the constantly lessening number of
causes of errors.
Finally the third part is entitled: Recent Data, Summary and
Conclusions. I first discuss the history which in the first part I
carried down only to my own work. Then I draw conclusions from
my whole series of researches. It will be seen that here my agree-
ment with M. Jourdanet could not be carried out literally, and that
I could not keep from trespassing somewhat on the domain
reserved for him.
The third and last chapter, whose title is General Conclusions,
XVIII
contains only three pages. May this temperance in the summary
bring me pardon for the eleven hundred and fifty pages which I
thought necessary in order to bring the reader to this point! I
leave to others the delicate task of deciding whether this antithesis
deserves criticism or praise. I shall merely remind the reader,
pleading at last extenuating circumstances, that since the Institute
did me the honor in 1875, on the recommendation of the Academy
of Sciences, of bestowing upon my work the grand biennial prize,3
it seemed to me that it was my duty to spare myself neither time
nor trouble to make the publication of my work more worthy of
this great award.
Before finishing this preface, I must thank M. Grehant and M.
Dastre, my assistants in the chair of physiology of the Faculty of
Sciences, Dr. Jolyet, assistant director of the laboratory, and M.
Paul Regnard, assistant in the course, who aided me in my research
with affectionate devotion.
P:B
October, 1877.
1 See my Lessons on the Comparative Physiology of Respiration; Paris, 1870, pages 121-130.
2 Paris. C>. Masson. 1875. Second edition. 1876.
3 This award of the first order is given every other year, according to the terms of the con-
stitutional decree, "to the work or discovery which has made the greatest contribution to the
honor or the service of the country" in the last ten years, in rotation for each of the branches
of human learning represented by the five classes of the Institute.
The triennial prize, by the decree of April 14, 1855, was decreed to M. Fizeau, in 18o6;
it was triennial only once, and by the decree of December 22, 1860, at the request of the Institute,
it became biennial, and since then the awards have been as follows:
To Thiers (Academie franQaise), 1861.
To Jules Oppert (Academie des inscriptions et belles-lettres), 1863.
To Wurtz (Academie des sciences) , 1865.
To Felicien David (Academie des beaux-arts), 1867.
To Henri Martin (Academie des sciences morales et politiques) , 1869.
To Guizot (Academie franQaise), 1871.
To Mariette-Bey (Academie des inscriptions et belles-lettres), 1873.
To Paul Bert (Academie des sciences), 1875.
To Chapu (Academie des beaux-arts), 1877.— (Editor's note.)
XIX
TABLE OF CONTENTS
First Part
HISTORICAL
Page
Title I. Diminished pressure 3
Preliminary chapter: the lofty regions of the globe. 3
Europe "
Asia 10
America *2
15
Africa
Islands 15
Summary 16
Eternal snows ^
Living organisms 18
First chapter. Mountain journeys — 22
1. South America 22
The Conquerors. Acosta. De Herrera. Frezier. Bouguer.
La Condamine. Don Ulloa. A. von Humboldt. Wars of Inde-
pendence. S. Haigh. Miers. Caldcleugh. Schmidtmeyer.
Brand. De la Touanne. Temple. Bollaert. D'Orbigny. Poep-
pig. Boussingault. Meyers. Ch. Darwin. Smyth and Lowe.
Arch. Smith. CI. Gay. Von Tschudi. De Castelnau. Weddell.
De Saint-Cricq. Gillis. Lloyd. Grandidier. Burmeister.
Markham. Martin de Moussy. Mateo Paz Soldan. Guilbert.
Pellegrino Strobel. Focke and Mossbach. Pissis. Wisse.
J. Remy. Steubel.
2. Central and North America 59
Wafer. Dollfus and 'de Montserrat. Burkhardt. Elliotson.
Glennie. Gros. Truqui and Craveri. Laverriere. Scientific
Commission of Mexico. Von Muller. Fremont. Gunnison.
Hines. Williamson. Coleman.
3. Etna 69
Bembo. Filoteo. Fazello. Borelli. Riedesel. Demeunier.
Houel. Delon. Dolomier. Spallanzani. Ferrara. De Gour-
billon. De Forbin. De Sayve.
XXI
Page
4. Peak of Teneriffe 73
R. Boyle. Edens. Feuillee. Glas. Riche and Blavier. Von
Humboldt. Cordier. L. de Buch. Dumont d'Urville. Le
Guillou. Ch. Sainte-Claire Deville. Itier. Madame Murray.
5. Alps _' 77
Bourrit. Laborde. De Saussure. Beaufoy. Forneret and Dor-
theren. De Lusy. Van Rensselaer. Hamel. Clissold. Clark
and Sherwill. Hawes and Fellowes. Auldjo. Meyer. Parrot.
Vincent and Zumstein. Molinatti. Hugi. H. Cloquet. Martin
Barry. Atkins. Mademoiselle d'Angeville. Desor. G. Studer.
Spitaler. Forbes. Lepileur. Bravais. Martins. Chomel and
Crozet. Tyndall. Tyndall and Frankland. Pitschner. Piachaud.
Lortet and Marcet. Durier. A. Tissandier. Hardy. Tuckett.
Kennedy. C. Grove. Visconti. Gamard. Joanne. Ormsby.
H. Russell.
6. Pyrenees 120
Rob. Boyle. Dralet. Ramond. Arbassiere. Cordier and Neer-
gaard. Parrot. De Franqueville. Russell-Killough. Le Mula-
hacen.
7. Caucasus. Armenia. Persia 123
Engelhardt and Parrot. Kupffer. Sjorgrun. Radde. Douglas
Freshfield. Gardiner.
Rob. Boyle. Tournefort. Parrot. Chodzko. Radde and Siev-
ers. Hamilton.
Taylor Thomson. R. F. Thomson.
8. Central Asia i 128
Marco-Polo. Hiouen. Tsang. Chinese Itinerary. Missionaries.
S. Turner. Th. Hardwicke. Moorcroft. Fraser. Webb.
Gerard Brothers. Johnson. V. Jacquemont. Wood. Burnes.
Father Hue. Hoffmeister. Th. Thomson. Dalton Hooker.
Robertson. Mistress Hervey. Oliver. Cheetam. Semenof.
Schlagintweit Brothers. Godwin-Austin. The Pundits. The
Mirza. Hayward. Faiz Buksh. Henderson. Hume. Drew.
9. Africa 161
Burton. Mann. Rebmann. De Decken. New.
10. Volcanoes of the Pacific 162
Low. Brooke. Braddel. Rutherford Alcock. Gubbins. Jef-
freys. Byron. D. Douglas. Loenenstern. Wilkes.
Chapter II. Balloon Ascensions 171
Charles and Robert. Leullier-Duche. Testu-Brissy. Blanchard.
De Lalande. Robertson. Garnerin. Zambeccari. Biot and Gay-
Lussac. Andreoli. Beaufoy and Sadler. Madame Blanchard.
Eug. Robertson. Green. Comaschi. Hobard. Barral and Bixio.
Welsh. Glaisher. Croce-Spinelli and Sivel. Simons.
Chapter III. Theories and Experiments 195
Acosta. Fr. Bacon. Academy del Cimento. Van Musschenbroeck.
Robert Boyle. Huyghens and Papin. Beale. Veratti. Cigna.
Darwin. Borelli. Bouguer. Ulloa. Haller. De Luc. Bourrit.
XXII
Page
De Saussure. Fodere. Halle and Nysten. Courtois. Legallois.
Dralet. Gondret. Fraser. Govan. Gerard Brothers. Hodgson.
H. Cloquet. Clissold. Roulin. J. Davy. Rostan. Cunningham.
Burdach. Poeppig. Boussingault. De Humboldt. Junod. Magen-
die. Favre. Barry. Martins. Rey. Tschudi. A. Smith. Hill.
Maissiat. Flechner. Brachet. Castel. Vierordt. Lepileur. A.
Vogt. Father Hue. Przevalski. Pravaz. Payerne. Marchal de
Calvi. Speer. Mayer-Ahrens. Lombard. Valentin. Heusinger.
Giraud-Teulon. F. Hoppe. Fernet. Longet. Gavarret. Duval.
Lombard. Martins. Guilbert. Jourdanet. His discussions with
Coindet. Cavaroz. Tardieu. Foley. Liguistin. Leroy de Meri-
court. Gavarret. A. Dumas. Scoutetten. Kaufman. Coindet.
Gavarret. Von Vivenot. Flemeing. Bouchard. Beclard. Hudson.
Piachaud. Lortet. Marcet. Forel. Clifford-Albutt. Dufour.
Javelle. Tyndall. Durier. Russell-Killough. Mistress Hervey.
Henderson. Drew. Burton. Hunt. Jaccard. Armieux. Gosse.
Jourdanet. The Academy of Medicine in 1875. Virlet d'Aoust.
Chapter IV. Summary and Criticisms 315
1. Conditions of the appearance of mountain sickness 315
2. Symptoms of mountain sickness 328
3. Theoretical explanations 335
Pestilential exhalations. Electricity. Lack of oxygen in the
air. Fatigue, cold. Theories of M. Lortet and M. Dufour.
Lessening of the weight supported by the body. Escape of
blood gases. Expansion of intestinal gases. Relaxing of the
coxo-femoral articulation. Other mechanical actions. Excess
of carbonic acid in the blood. Theory of de Saussure and
Martins. Theory of M. Jourdanet.
Title II. Increased Pressures 353
Chapter I. High pressures 355
1. Diving bells 355
Sturmius. Halley. Spalding. Brize-Fradin. Hamel. Colladon.
2. Apparatuses constructed in the Triger method 358
Papin. Triger. Trouessart. De la Gournerie. Blavier. Pol
and Watelle. Comte. Bouhy. Brunei. Cezanne. Regnauld.
Babington and Cuthbert. Francois, Bucquoy. Foley. Nail.
Hermel. Limousin. Bayssellance. Gallard. Triger. Barella.
Eads. Bauer. Malezieux. Unpublished information.
3. Divers with suits 390
Borelli. Halley. Leroy de Mericourt. Denayrouze. Gal.
Sampadarios.
Chapter II. Low pressures 411
Junod. Tabarie. Pravaz. Milliet. Sandahl. Tutschek. G.
Lange. Vivenot. Freud. Elsasser. Panum. G. Liebig.
Mayer. Marc.
XXIII
Page
Chapter III. Theoretical Explanations and Experiments 440
Borelli. Musschenbroeck. Haller. Achard. Brize-Fradin. Halle
and Nysten. Poiseuille. 'Maissiat. Hervier and Saint-Lager.
Pravaz. Pol and Watelle. A. Guerard. Milliet. Eug. Bertin.
Hoppe. Francois. Bucquoy. Hermel. Foley. Caffe. Babing-
ton and Cuthbert. Sandahl. Tutschek. Vivenot. G. Lange.
Elsasser. Panum. G. Liebig. Gavarret. Leroy de Mericourt.
Bouchard. Gal.
Chapter IV. Summary and Criticisms 489
1. Physiological action of compressed air.
A. Phenomena due to compression.
B. Phenomena due to decompression.
2. Theoretical explanations.
A. Phenomena due to compression.
Physico-mechanical explanations. Chemical explana-
tions.
B. Phenomena due to decompression.
Second Part
EXPERIMENTS
Chapter I. Chemical conditions of the death of animals subjected to
different barometric pressures in closed vessels 505
Subchapter 1. Pressures below one atmosphere 507
1. Experimental set-up 507
2. Experiments : 513
A. Experiments on birds 513
B. Experiments on mammals 542
C. Experiments on cold-blooded animals 550
3. Conclusions 552
Subchapter 2. Pressures above one atmosphere 552
1. Experimental set-up 552
2. Experiments 555
A. Compressions with ordinary air 555
B. Superoxygenated air; pressures between one and
two atmospheres 560
C. Compressed air at very high pressures.
Lethal action of oxygen 565
D. Compression with air of low oxygen content 570
E. Compression with superoxygenated air 571
F. Compression with ordinary air; elimination of
carbonic acid 574
3. Conclusions 577
Subchapter 3. Summary and conclusions 578
XXIV
628
Page
Chapter II. Gases contained in the blood at different barometric
pressures ' 581
Subchapter 1. Operative methods and experimental discussion __. 581
Subchapter 2. Blood gases under pressures less than one atmos-
phere 594
1. Experimental set-up 594
2. Experiments - 600
Subchapter 3. Blood gases under pressures greater than one
atmosphere 615
1. Experimental set-up 615
2. Experiments - 618
Subchapter 4. Blood gases in asphyxia compared to decreased
pressure ■-—
Subchapter 5. The quantity of oxygen which the blood taken
from the vessels can absorb at different barometric
pressures 641
1. Pressures lower than one atmosphere 643
2. Pressures greater than one atmosphere 654
Chapter III. Phenomena presented by animals subjected to pressures
less than one atmosphere 660
Subchapter 1. Symptoms of decompression 661
1. Respiration _' 666
2. Circulation 669
3. Digestion 672
4. Nervous and muscular effects 673
5. Nutrition 675
Chemical phenomena of respiration. Urinary excretion.
Sugar of the liver and blood, glycosuria. Temperature.
Development.
6. Lower limit of pressure 685
7. Death 687
Subchapter 2. Comparison of the phenomena of decompression
with those of asphyxia in closed vessels 689
Subchapter 3. Means of warding off the symptoms caused by de-
compression 694
Chapter IV. Action of compressed air on animals 709
Subchapter 1. Toxic action of oxygen at high tension 709
2. The diminution of oxidations caused by oxygen poisoning 743
3. Aquatic or invertebrate animals 751
Subchapter 2. Action of compressed air at low pressures - 754
1. Short stay in compressed air 756
A. Experiments made upon myself 756
XXV
Page
B. Production of urea; experiments on dogs 764
C. Chemical phenomena of respiration 765
D. Pulmonary capacity 768
E. Intra-pulmonary pressure 771
F. Arterial pressure 773
2. Prolonged stay in compressed air 775
Chapter V. Influence of changes in barometric pressure on plant life 780
Subchapter 1. Pressures less than one atmosphere 782
1. Germination ._ 782
2. Vegetation 787
Subchapter 2. Pressures above one atmosphere 788
1. Germination 788
A. High pressures with air of low oxygen content 792
B. Normal pressure; superoxygenated air 793
C. Low pressures; superoxygenated air 794
2. Vegetation 797
Subchapter 3. Summary 798
Chapter VI. Action of changes in barometric pressure on ferments,
poisons, viruses, and anatomical elements 799
Subchapter 1. Fermentations by organisms 800
1. Putrefaction 800
A. Meat 800
B. Blood 817
C. Eggs 819
2. Coagulation of milk 820
3. Alteration of the urine 823
4. Brewer's yeast 826
5. Wine ferments 827
6. Molds 831
Subchapter 2. Diastatic fermentations 834
1. Saliva and diastase 835
2. Pepsin 837
3. Inversive ferment of yeast 838
4. Myrosin 838
5. Emulsin 839
Subchapter 3. Action of oxygen at high tension upon anatomical
elements 839
Subchapter 4. Use of oxygen at high tension as an experimental
method 842
1. Dry rot of fruit 843
2. Ripening of fruits 844
3. Venoms 845
4. Viruses 846
XXVI
Page
A. Vaccine 846
B. Glanders 847
C. Anthrax 847
Subchapter 5. Summary 849
Chapter VII. Effects of sudden changes in barometric pressure— . 852
Subchapter 1. Effects of sudden increases in pressure 852
Subchapter 2. Effects of sudden decreases in pressure beginning
with one atmosphere 853
Subchapter 3. Effect of sudden decrease in pressure beginning
with several atmospheres 859
1. Decompression without interruption 859
A. Experiments on sparrows 859
B. Experiments on rats 861
C. Experiments on rabbits 861
D. Experiments on cats 861
E. Experiments on dogs 863
2. Slow decompression in several stages 874
3. Summary and conclusions from the preceding experiments 878
Subchapter 4. Prophylaxis and treatment of the symptoms of sud-
den decompression 890
Subchapter 5. Summary 895
Chapter VIII. Various questions 896
Subchapter 1. Action of carbonic acid on living beings 896
1. Lethal tension of carbonic acid in ambient air 896
2. Lethal concentration of carbonic acid in the blood 899
3. Accumulation of carbonic acid in the tissues 910
4. Symptoms and mechanism of carbonic acid poisoning 914
5. Action of carbonic acid on lower living beings 924
6. Summary and conclusions 927
Subchapter 2. Asphyxia — 928
Subchapter 3. Observations on the gases of the blood 935
Third Part
RECENT DATA, SUMMARY AND CONCLUSIONS - 947
Chapter I. Decreased pressure 949
Subchapter 1. Observations, theories, and recent discussions 949
Bouchut. Chabert. Dufour. Forel. Thorpe. Tempest An-
derson. Calberla. Ward. Vacher. Croce-Spinelli, Sivel and
G. Tissandier. Stoliczka. Campana. Jourdanet.
XXVII
Page
Subchapter 2. Summary and practical applications 980
1. Aeronauts 981
2. Mountain travellers 991
3. Dwellers in high places 998
4. Animal and plant life at high elevations 1005
5. Medical applications 1006
Chapter II. Increased pressure 1009
Subchapter 1. Observations, theories, and recent discussions 1009
1. High pressures 1009
Guichard. Heiberg.
2. Low pressures. Medical apparatuses 1014
J. Pravaz. G. Liebig. Leonid Simonoff.
Subchapter 2. Summary and practical applications 1021
1. High pressures 1021
2. Low pressures^ _i 1024
3. Sudden decompression 1027
4. Practical applications. Therapeutics and hygiene 1027
5. Conclusion from the point of view of general natural history 1032
Chapter III. General conclusions 1036
Addenda I. Relations between heights and barometric pressures 1039
II. The new work of Dr. Mermod 1041
Index — 1045
XXVIII
Fig.
1.
Fig.
2.
Fig.
3.
Fig.
4.
Fig.
5.
Fig.
6.
Fig.
7.
Fig.
8.
LIST OF ILLUSTRATIONS
Page
Lortet. Respiratory tracing taken at Lyons (200 meters) 112
Lortet. Respiratory tracing taken at the summit of Mont
Blanc (4810 meters), after resting an hour 112
Cupelain: Chamounix (1000 meters) - 113
Grands-Mulets (3000 meters) at midnight, half an hour before
starting H3
Summit of Mont Blanc (4810 meters) 113
The construction of a bridge pier by the use of caissons 369
Diver equipped with the Denayrouze regulator, complete suit 391
Diver equipped with the Denayrouze regulator, helmet re-
moved 392
Fig. 9. The aerotherapeutic establishment of Dr. Carlo Fornanini at
Milan 412
bis. Respiratory modifications in compressed air 423
Circulatory modifications in compressed air - 424
Circulatory modifications in compressed air 424
Circulatory modifications in compressed air 425
Circulatory modifications in compressed air 425
Circulatory modifications in compressed air 430
Apparatus with four plates for experiments on decreased
pressure 508
Mercury pump set up for the extraction of the gases of the
blood 510
Composition of confined air which has become lethal at pres-
sures below one atmosphere 524
Variations in the tension of the oxygen contained in com-
pressed air which has become lethal at various pressures
less than one atmosphere 527
Relations between the oxygen tension, duration of life, and
capacity of vessels 531
Cylindrical glass apparatus for high pressures (25 atmos-
pheres) set up for superoxygenated air 554
Confined air which has become lethal under pressure 568
XXIX
Fig.
9.
Fig.
10.
Fig.
11.
Fig.
12.
Fig.
13.
Fig.
14.
Fig.
15.
Fig.
16.
Fig.
17.
Fig.
18.
Fig.
19.
Fig.
20.
Fig.
21.
Fig.
23.
Fig.
24.
Fig.
25.
Fig.
26.
Fig.
27.
Fig.
28.
Fig.
29.
Fig.
30.
Fig.
31.
Fig.
32.
Fig.
33.
Fig.
34.
Fig.
35.
Page
Fig. 22. Confined air which has become lethal under pressures from
20 centimeters to 24 atmospheres 576
Graduated syringe for the extraction of blood 582
Mercury pump set up for the extraction of the gases of the
blood 583
Small mercury reservoir 588
Bellows for artificial respiration 591
Large apparatus for the study of low pressures 595
Dog prepared to be placed in the cylinders of Fig. 27, and for
the extraction of blood under decreased pressure 596
Different forms of cannulae for the extraction of blood under
decreased pressure 598
Extraction of the blood of an animal under decreased pres-
sure 599
Decrease of the quantities of Oa and C02 contained in the
arterial blood, when the barometric pressure is diminished 608
Percentage decrease of the 0= and the C02 of the arterial
blood when the barometric pressure is diminished,-- 611
Large compressed air apparatus, cylinder of sheet steel cap-
able of withstanding a pressure of 12 atmospheres 616
Extraction of blood from an animal placed in compressed air 618
Variations of the gases of the blood at pressures above one
atmosphere 623
Fig. 36. Increase of the oxygen of the arterial blood from 0 to 10
atmospheres and from 0 to 26 atmospheres 624
Dog breathing air from a rubber bag 629
Variations of the gases of the blood and the oxygen of the
air in asphyxia in closed vessels, when the carbonic acid
is absorbed 633
Variations in the gases of the blood in asphyxia compared
to decreased pressure 635
Decrease of the gases of the arterial blood and the venous
blood when the tension of oxygen breathed decreases 639
Flask arranged for saturating blood with oxygen under dif-
ferent decompressions 644
Water motor shaking the flask containing the blood to be
saturated with oxygen 645
Capacity of the blood for absorbing oxygen at pressures be-
low one atmosphere 648
Apparatus to bring blood into contact with the air at a speci-
fied decrease in pressure 650
Apparatus for saturating blood with air at high pressures 654
Oxygen capacity of the blood from a vacuum to 18 atmos-
pheres of air 656
Modification of the number of respiratory movements under
the influence of decompression. (Dogs, rabbits) 667
Same (Guinea pig, Experiment CCXXVII) 668
XXX
Fig.
37.
Fig.
38.
Fig.
39,
Fig.
40.
Fig.
41.
Fig.
42.
Fig.
43.
Fig.
44.
Fig.
45.
Fig.
46.
Fig.
47.
Fig.
48.
Fig.
50.
Fig.
51.
Fig.
52.
Fig.
53.
Fig.
54.
Fig.
55.
Fig.
56.
Fig.
57.
Fig.
58.
Fig.
59.
Fig.
60.
Fig.
61.
Fig.
62.
Page
Fig. 49. Simultaneous modifications of the number of respiratory-
movements R and pulse P under the influence of decom-
pression; (Cat, Experiment CCXXI) 670
Same (Dog, Experiment CCXVIII) 671
Same (Dog, Experiment CCXVII) 671
Consumption of oxygen and production of carbonic acid at
different pressures 677
Asphyxia without carbonic acid 691
Maxima and minima of cardiac pressure in asphyxia without
carbonic acid 692
Bird in air progressively rarefied and oxygenated 695
Respiration of superoxygenated air expanded by decrease
of pressure 697
Sudden modifications in the pulse rate by intermittent respi-
ration of superoxygenated air 699
Modifications in the pulse rate, during decompression, result-
ing from the continuous respiration of oxygen (Experi-
ment CCLVI) 705
Same (Experiment CCLVII) 707
Dogs poisoned by oxygen 739
Dog during tonic convulsions of oxygen poisoning 741
Apparatus of M. Jourdanet for the therapeutic use of com-
pressed or expanded air 757
Fig. 63. Gas meter for the measurement of the respiratory move-
ments 758
Fig. 64. Apparatus with double valve for the study of respiration___ 759
Fig. 65. Apparatus for the chemical study of the respiration of an
animal kept for any specified time in air of constant
composition ^ 766
Fig. 66. Apparatus for the observation of variations in the intrapul-
monary air tension 771
Variations of the intra-thoracic tension. Normal pressure___ 772
Same. Compressed air 772
Tension of the blood in the femoral artery. Normal pressure 773
Same. Compressed air 773
Tension of the blood in the carotid artery. Normal pressure 774
Same. Compressed air 774
Same. Normal pressure 774
Oxygen consumption and carbonic acid production by a piece
of meat in an atmosphere of constant oxygen content 813
Death by carbonic acid; changes in the air of the bag (Experi-
ment DCXV) 915
Death by carbonic acid; changes in the composition of the
gases of the blood, the respiration, and the circulation
(Experiment DCXV) 917
XXXI
Fig.
67.
Fig.
68.
Fig.
69.
Fig.
70.
Fig.
71.
Fig.
72.
Fig.
73.
Fig.
74.
Fig.
75.
Fig.
76.
Page
Fig. 77. Death by carbonic acid; relation of the respiration and the
circulation to the carbonic acid content of the blood
(Experiment DCXV) 919
Fig. 78. Death by carbonic acid; last respiratory movements (Experi-
ment DCXV) 920
Fig. 79. Death by asphyxia in a closed vessel; gases of the air (Exper-
iment DCXL) 932
Fig. 80. Same; gases of the blood (Experiment DCXXXIV) 932
Fig. 81. Relation between the oxygen content of the air and that of
the blood 933
Fig. 82. Pulse at the Riffel Pass (2780 meters), during an attack of
mountain sickness 955
Pulse at the Sattel-Tolle (4300 meters) 955
Pulse at the Riffel (2569 meters), rest on the return trip 956
Pulse at Morges (380 meters), absolute repose 956
The basket of the Zenith at a high altitude 966
Diagram of the high altitude ascension on April 15, 1875 970
Portrait of Sivel 972
Portrait of Croce-Spinelli 973
Fig.
83.
Fig.
84.
Fig.
85.
Fig.
86.
Fig.
87.
Fig.
88.
Fig.
89.
XXXII
Part I
HISTORICAL
Title I
DIMINISHED PRESSURE
Preliminary Chapter
THE LOFTY REGIONS OF THE EARTH
The effects produced upon the organism by a great and sudden
decrease in the barometric pressure can be observed in three dif-
ferent cases: mountain journeys, balloon ascensions, and experi-
ments under pneumatic bells.
These last two methods were absolutely unknown to the an-
cients. Galileo, as everyone knows, was the first to have a clear
idea of the pressure of the air; it was not until 1640 that Toricelli
invented the barometer, or until 1650 that Otto de Guericke in-
vented the pneumatic machine. In 1648, at the suggestion of our
great Pascal, Perier made at Puy-de-D6me the memorable experi-
ment in which he saw the height of the barometric column de-
crease in proportion to the increase of the altitude of the place
where it was observed.
For balloons, the discovery is still more recent. The first hot air
balloon which carried aloft Pilatre du Rozier and the Marquis
d'Arlandes, ascended from Paris November 22, 1783; a few days
after, December 1, Charles made an ascension with the hydrogen
balloon which he had just invented. This balloon, however, was
not able to carry the observers high enough for the decrease of
pressure to make its effect felt upon them. In fact, the experiment
proved that this effect is not clearly evident in a balloon below an
altitude of 5,000 or 6,000 meters. Consequently, among the thou-
sands of ascents which followed that of Charles and Robert, only
a very small number can be of interest to us in our particular
purpose and therefore be reported in this historical review.
4 Historical
As to the third condition, the ascent of high mountains, at first
glance it seems astonishing to have to state that the ancient authors
have left us no precise information permitting us to believe that
they noted, during the ascent of lofty mountains, any physiological
symptoms worthy of attracting attention.1
In fact, in the part of the world known to the ancients, there
are mountains of considerable height. At its extreme eastern
limits,2 Mount Ararat and the chief peaks of the Caucasus raise
their heads covered with eternal snow more than 5,000 meters
above sea level; the chains of Liban and Taurus contain many
peaks more than 2,500 or even 3,000 meters high; the famous Mount
Argaeus reaches a height of 3,840 meters; among the hills of Hemus
and Rhodope, some rise to 3,000 meters; Mount Athos is 1,975 meters
high, Parnassus 2,470, Taygetus 2,400, and it is at 2,975 meters, on
the towering brow of Olympus, that the poets placed the abode of
the gods. Mount Etna (3,310 meters) for two thousand five hun-
dred years has been threatening the Greek cities settled at its feet.
The Phenicians and the Carthaginians, whose daring had established
colonies as far away as the Fortunate Isles, knew the smoking peak
of Teneriffe (3,715 meters). Finally, the Pyrenees and the Alps
were insufficient barriers against the armies of Carthage and Rome.
The reason for the silence of the authors is easily found. As
von Humboldt very correctly said, the ancients feared mountains
much more than they admired them. They spoke of them only with
fear, with a secret horror; the magnificent spectacles they offer to
the gaze did not affect them; the emotions they arouse, the noble
ideas they inspire were unknown to the ancients. Love of the pic-
turesque is a very modern sentiment; the ancients, and even our an-
cestors up to the last century, would have regarded with an aston-
ishment mingled with disdain our intrepid climbers of the Alps.
Polybius first passed through the Alpine valleys; the highest moun-
tains, Mont Blanc, Monte Rosa, the Jungfrau, have no names in
the classical languages.
The only mountain which the ancients climbed without being
forced to is Etna. Seneca requests his friend Lucilius Junior to
climb to the top of the volcano in his honor (Letter 79) ; these
excursions were frequent in the time of Strabo,:i and according to
a poem attributed today to this same Lucilius, priests burned in-
cense on the edge of the crater to appease the gods; the emperor
Hadrian, who was a great traveller, conceived the idea of climbing
to the top of Etna to see the sunrise. None of these accounts speak
of physiological symptoms; but we shall see that at the height of
Lofty Regions of the Globe 5
this volcano they are slight, attack only part of the travellers, and
might be confused with the ordinary effects of fatigue. The same
thing is true in crossing the Pyrenees and the Alps. The passes of
the Pyrenees, through which regular communications were estab-
lished between Gaul and Hispania, are hardly 1,500 meters high.
Whatever opinion one has about the site of the passage of Hannibal,
either at the Little Saint-Bernard (2,160 meters), or the pass of
Mount Viso (2,700 meters), or Mount Cenis (2,080 meters), or in
the valley of Beaufort between Albert- Ville and Chamounix, the
heights reached were not very great. Augustus had two roads made
through the passes of the Great Saint-Bernard (2,490 meters) and
the Little Saint-Bernard,4 and King Cottus, his contemporary, cut
the road of Mount Cenis. In the Middle Ages, the Simplon (2,020
meters) and the Great Saint-Bernard were much frequented;
chroniclers have left us descriptions of these journeys or these
expeditions in which the terrible difficulties of the roads, the ex-
cessive fatigue, and the cold explain sufficiently the pitiful state
of the travelers, many of them, like Elfrid, archbishop of Canter-
bury, perished in the snow.
To attract the attention of the travellers to physiological symp-
toms they would have had to make more lofty ascents, and to have
suffered discomforts evidently unexplainable by ordinary causes.
The lofty summits of the Alps presented the necessary conditions,
as we shall see; but since their ascents offered no practical interest,
they were undertaken only toward the end of the last century.
But twenty years after the discovery of America, the conquest of
Mexico and Peru and military expeditions across the Cordilleras
brought the Spaniards into conditions where the symptoms of de-
compression appeared definitely. So attention was soon attracted
to them, and they were noted in ascents where they are neither
great nor constant, like those of Etna and the Peak of Teneriffe.
However, our Alps for a long time still remained unexplored;
though the important cities and the rich valleys of Switzerland
attracted many travelers, no one had the idea of climbing these
dangerous peaks covered with snow, peopled with strange beings,5
and about which the most gloomy tales were told. It was not until
the second half of the eighteenth century that people decided to
admire them and that the idea of reaching their summits germi-
nated in a few minds. It was the scientific point of view that
guided the first ascents. In the account of his ascents de Saussure
noted with keen alertness the symptoms brought on by a stay in
rarified air. Since then, similar observations are numerous. Still
6 Historical
more recently, officers, scholars, and English travelers have carried
their explorations into the loftiest regions of the Himalayas. Their
accounts, added to those of men who have ascended the Alps and
of travellers in America, which have become more numerous, have
familiarized physicians with the symptoms of mountain sickness.
In the following pages I shall report most of the interesting facts
collected thus by eyewitnesses, often from their own personal ob-
servation. But in this preliminary chapter I should like to recall
to the memory of the reader the different mountain regions in
which the traveller is exposed to distress in consequence of the
decrease of pressure. This simple enumeration will show him the
practical importance of the question which we shall discuss here,
that is, the manifestation by acute and violent symptoms of the
effect of decreased pressure.
Rarely does mountain sickness appear with marked intensity in
our temperate regions below an altitude of 3,500 meters. In the
tropics, one must mount to more than 4,000 meters to experience
it definitely in ordinary conditions. We shall return to these limits
and take account of the different circumstances which hasten or
delay the symptoms, I mean by that, cause them to appear at a
lower or higher altitude. For the moment, these approximate
heights serve as a basis for the review we intend to make.
Europe. Let us take Europe first; the Alps, the Pyrenees, and
the Caucasus are almost the only mountain chains which offer us
peaks high enough for their ascent to cause any other ill conse-
quences than the weariness and the dangers customary in moun-
tains.
Let us first examine the Alps. This enormous mass of moun-
tains which includes in a curved line two hundred leagues long
innumerable peaks laden with eternal snows, descends rapidly on
the south to the low plains of Lombardy, while on the north it
slopes more slowly towards the high plateaux of Wurtemberg,
Bavaria, and Bohemia, interrupted by secondary mountains.
The heart of the system is formed by the group of Saint-Gothard,
whose waters flow at the same time through the Rhine into the
North Sea, through the Rhone into the Mediterranean, and through
the Tessin into the Adriatic; and yet this region is one of the least
elevated of the Central Alps. It is immediately dominated on the
north by Galenstock (3800 meters) and Todi (3600 meters); on
the east, by the group surrounding the Little Saint-Bernard, among
others the Rheinwaldhorn (3400 meters) ; on the west, by the
enormous mass of the glaciers of the Bernese Alps, in the midst of
Lofty Regions of the Globe 7
which rise the Jungfrau (4170 meters), the Aletschhorn (4200
meters), the Schreckhorn (4080 meters), the Brietsch (3950
meters), the Monk (4100 meters), and the Finsteraarhorn (4270
meters) . Advancing toward the east, we see Mount. Bernin (4050
meters) and Mount della Disgrazia (3680 meters) separating the
valley of the Valteline, in which flows the Adda, from that of the
Engadine, in which the Inn conducts by the Danube to the Black
Sea the waters brought to it from numerous peaks more than 3000
meters high, such as the Piz d'Err (3390 meters), the Piz Linard
(3410 meters) , the Piz Languard (3270 meters) , etc. On the other
bank of the Adda, the Tyrolese Alps display still loftier peaks; the
Adamello (3560 meters), the Wildspitze (3770 meters), the
Venediger (3675 meters), the Gros-Glockner (3890 meters), and
especially the Orteler (3920 meters) .
But it is towards the west and on the left bank of the Rhone
that the giants of the Alps rise. First, around the Simplon (3200
meters), are Monte-Leone (3560 meters), the Fletschhorn (4020
meters) , and the Weismies (4030 meters) ; then the base of Monte
Rosa, with its three surmounting peaks; the Dome du Mischabel
(4550 meters) , the Matterhorn or Mount Cervin (4480 meters) , and
Monte Rosa itself, the highest peak of which, the Pointe de Dufour,
rises to 4640 meters. Next come the Dent-Blanche (4360 meters) ,
the Weisshorn (4510 meters) , the Grand Combin (4320 meters) ,
and farther to the west Mont Blanc (4810 meters) , which, sur-
rounded by numerous almost inaccessible pinnacles, dominates all
the other mountains of Europe.
Beyond, the chain drops rapidly, although it still displays a few
lofty summits, such as Mount Iseran (4045 meters), Mount Cenis
(3620 meters), the Vanoise (3860 meters), in the Graies Alps;
Mount Viso (3840 meters) . Mount Olan (4215 meters) , in the Cot-
tian Alps; Mount Pelvoux (3955 meters), the Pointe des Ecrins
(4100 meters) , the Grandes Rousses (3475 meters) , in the Alps of
Dauphine. The Maritime Alps are still less lofty; finally come the
Apennines, the highest peak of which, Monte Corvo, in the Abruzzi,
is only 2910 meters high. But beside these giants, what an ap-
pearance the Capitol makes with its 47 meters above sea level!
At the end of the chain, a rather high mountain, Mount Alto
(1080 meters), faces Sicily, the hilly soil of which, like that of
Sardinia, has no peaks reaching 2000 meters. Above all these sec-
ondary mountains the crater of Etna rises to 3310 meters.
Among these high peaks, these abrupt pinnacles, which are
climbed only by those inspired by love of science, a taste for grand
8 Historical
views, or merely vanity, depressions called cols allow many travel-
lers at certain points to cross the principal chain from Switzerland
or France to Italy. These passes are generally very high. The best
known and the highest are: in the Maritime Alps, the passes of
Tende (1870 meters), of Longet (3150 meters), of the Argentiere
(1905 meters), and of Maurin (2980 meters); in the Cottian Alps,
the passes of Traversette (2995 meters), of the Agnello (2700
meters), of Sayse (3360 meters), of Mount Genevre (1850 meters);
in the Graies Alps, the pass of Mount Cenis (2080 meters) , and of
the Little Saint-Bernard (2160 meters) ; in the Pennine Alps, the
pass of the Grand Saint-Bernard (2490 meters) , that of the Geant
(3360 meters) , of the Seigne (2530 meters) , the pass of Balme (2200
meters) , the pass of Saint-Theodule (3320 meters) ; in the Helvetian
Alps, the Simplon pass (2020 meters), the pass of Gemmi (2300
meters), the pass of Grimsel (2160 meters), that of the Fourca
(2460 meters), of the Saint-Gothard (2110 meters), of Bernardin
(2060 meters) , etc. The road of the Valteline, the highest carriage
road in Europe, crosses the pass of Stelvio at 2810 meters, going
from the basin of the Po to that of the Danube.
Along the Adriatic, the Alps continue by the mountains of
Croatia, Montenegro, and Serbia, with the Balkans at the north
and on the south the Rhodope mountains and the chain of Pindus
which gives birth to the hills of Greece. In these very hilly regions,
the summits of which are however not very high, we need mention
only the Dormitor (2260 meters) in Herzegovina, the Kom (2290
meters) in Montenegro, the Kriwosta (2440 meters) in Roumania;
then the giant of the Rhodope mountains, the Rilo Dagh (2815
meters), and finally the mountains of Greece of which we have
already spoken.
The Danube, which receives the waters of the north slope of
the Alps, rises in the mountain group of the Black Forest, in which
there are a few peaks of moderate height; after running towards
the east, it encounters the chain of the Carpathians, in which there
are such peaks as the Tatra (2655 meters), the Gailuripi (2925
meters), the Ruska-Poyana (3020 meters), and which pushes it
towards the south.
The mountains of the interior of France have no interest for us
from the standpoint of our present purpose, since the highest,
Mount Dore, is only 1890 meters high; the little chain which crosses
Corsica is more interesting; its highest point, Mount Cinto, rises to
2710 meters.
But the Pyrenees, in a length of 150 kilometers and a maximum
Lofty Regions of the Globe 9
width of 120 kilometers, have a large number of peaks which, al-
though they do not have the imposing mass or the height of the
Alpine groups, are nevertheless important for our purpose. In the
eastern Pyrenees there are first the Canigou (2785 meters) , then
the Puigmal (2910 meters) and the Corlitte (2920 meters), domi-
nating on each side the pass of the Perche (1620 meters) ; finally
from this pass to the valley of Aran, on a very lofty crest, a series
of peaks reach a height of 2800 meters, the highest of which is the
Montcalm (3090 meters).
Beyond the valley, the western Pyrenees begin with the group
of the Maladetta, which contains their highest point, the peak of
Nethou (3405 meters). This is the center of the Pyrenees group,
which in a length of some hundred kilometers contains a great
number of summits rising above 3000 meters: the peak of Perdi-
ghera (3220 meters) , the cylinder of Marbore (3330 meters) , Mount
Perdu (3350 meters), Vignemale (3300 meters), Marmure (2950
meters) , the southern peak of Ossau (2885 meters) ; and to the
north of the principal chain, the peak Campvieil (3175 meters),
and the southern peak of Bigorre (2880 meters) , on which a mete-
orological observatory has just been established. The passes or
ports of this region also attain a considerable height: port of Viella
(2455 meters) , port of Venasque (2420 meters) ; the lowest is the
port of Gavarnie (2280 meters) , the highest is the Portillon (3045
meters) .
Towards the west, the chain drops rapidly; then, the Pyrenees
proper give way to the Cantabric Mountains, which extend to the
end of Galicia. In this whole extent, only a few summits rise above
2000 meters. In the rest of Spain, the Sierra Guadarrama and the
Sierra de Gredos, which dominate Madrid and pour upon it the
dreaded wind of the mountains, rise at certain points to more than
3000 meters; finally along the sea, at the highest point of the Sierra
Nevada, the twin summits of the peak of Veleta (3470 meters) and
the Cerro de Mulhacen (3555 meters) surpass the highest of the
Pyrenees.
In the rest of Europe, there are no mountains which can attract
our attention. Ben Nevis, the highest mountain in the British
Isles, is only 1330 meters high; in Iceland, Orafa Jokul is 1950
meters; in the Scandinavian Alps, the highest mountains are Snee-
hatten (2300 meters), Skagstolstinder (2450 meters), and Ymes-
Feldj (2600 meters) ; in the Ural Mountains, there are no peaks
reaching the height of 2000 meters; the highest, T611-pos-Is, is only
1680 meters.
10 Historical
Asia. But on the borders of Europe and Asia, a considerable
chain, the Caucasus, extending from the Caspian to the Black Sea,
bordering on the north upon plains, and on the south upon the
mountainous regions of Armenia whose ramifications we shall fol-
low presently, is crowned by peaks which leave far below them
the Pyrenees and the Alps themselves. Peaks of 3000 to 4000
meters are numerous there and they are dominated by Kasbek
(5030 meters) , Kaschtantan (5220 meters) and Elbruz, 'to which the
legend fastens Prometheus (5620 meters) . Only one carriage road
crosses the chain at the foot of Kasbek, by the Caucasian gates of
the ancients, at a height of more than 3000 meters.
At the south of the Caucasian chain, in the hilly territory of
Armenia there rise a series of peaks, some of which reach the height
of 40.00 meters: Alagos (4090 meters), Kapudschich (3920 meters);
above them towers the Grand Ararat (5155 meters) . From this
group there extends towards the southwest the chain of the Taurus,
which contains several summits more than 3000 meters high, the
highest of which are Metdesis (3570 meters) and Mount Argea
(3840 meters) ; in the Liban, a fork of the Taurus, the highest
summit, Dor-el-Chodib, is only 3065 meters high. At the south,
the mountains of Kurdistan, with Dschehil (4550 meters) ; to the
southeast, the Elburs mountains, with Sawalan (4810 meters) and
Demavend (5620 meters), dominate the vast plains of Iran.
The center of Asia displays an orographic system much more
complex and masses of mountains much more imposing. The trav-
eler who goes up the Ganges sees rising on his right, from Boutan
to Cashmere, over a stretch of more than 600 leagues, the formi-
dable range of the Himalayas; from between the parallel lesser
chains descend innumerable tributaries of the great Indian river.
In this range are found the highest mountains in the world; the
ridge reaches an average height of 5000 to 6000 meters; we can
count by the hundred summits of more than 6000 meters; peaks
less than 7000 meters high are generally marked scornfully on the
English maps by mere numbers, and it seems as if mountains do
not deserve to have a name unless they reach a height of 8000
meters.
We shall mention: in Boutan, Dalla (7030 meters), the Oodoo
Mountains (7540 meters) , Chamalari (7300 meters) ; in Sikkim,
Mount Doukia (7070 meters) and Kantschin-Janja (8580 meters) ;
this latter yields only to Gaurisankar or Mount Everest in Nepal,
the highest mountain on earth, which raises its summit to the pro-
digious height of 8840 meters; we should gain this height by heap-
Lofty Regions of the Globe 11
ing the Jungfrau (4170 meters) upon Monte Rosa (4640 meters) ;
it is more than seven times the height of Vesuvius (1190 meters).
Also in Nepal, Jangmar (7930 meters), Djibjibia (8020 meters),
Jassa (8135 meters), Marschiadi (8080 meters), Barathor (7950
meters) , and finally Dawalaghiri (8185 meters) , long considered
the highest of all, but now known to be surpassed by Guarisankar.
Then the Himalayan chain opens to allow the passage of the
Setledj, which carries to the Indus the waters of the northern
slope and those of the sacred lake of Manasarovar (4650 meters) .
Beyond, it ends in the extraordinary maze of the mountains of
Cashmere, in the midst of which opens the delightful valley of
Srinagar, the "earthly paradise" of the Hindus.
At their eastern end, the Himalayas are joined to the Langtan
Mountains, the heart of chains of relatively moderate height, which
form the high relief of China and Indo-China.
The Himalayas thus form, on their southern slope, the gigantic
talus of a high mountain plateau, as it were. This is Tibet, which
over an immense extent rises above 3000 meters, and whose waters,
collected in the Brahmapoutra, flow first towards the east, then,
encountering the mountains of China, turn to the southwest, to
join those of the Ganges. On the north, this plateau is bounded
by the chain of Kuen-Loun; its western extremity is traversed
by the chain of Karakorum, the summits of which rival those of
the Himalayas, such as Dapsang (8620 meters), Diamer (8130
meters) , and Gusherbrum (8040 meters) .
Passes, the elevation of which naturally increases as the highest
ridges are approached, permit a crossing of the foothills of these
principal chains, and finally of the chains themselves. Many of
these passes, which are much travelled, are at a height of more
than 5000 meters; the famous pass of Karakorum is 5650 meters
high; the Yangi-Diwan Pass, one of the routes from Cashmere to
Khotan across the Kuen-Loun chain, is 5820 meters high; the high-
est ,; of all in the British Empire, the pass of Parang, has an eleva-
tion of 5835 meters.
The traveler who climbs the steps of this sort of gigantic stair-
way descends between them much less than he has ascended; thus
he reaches a vast desolate plateau; this is the Pamir (visited in
the thirteenth century by Marco Polo), or the Bam-i-Dunya, that
is, the roof of the world, whose average altitude is more than 4500
meters. On the east, this roof slopes down to the lofty plains of
upper Tartary, and its waters, through the river Tarim, are lost in
12 Historical
the desert of Gobi. Towards the west, they collect in the Oxus
which carries them to the Lake of Aral.
Other chains, of a considerable absolute elevation, rise above
these high plateaux. On the northeast, Thian-Schan, whose cul-
minating point is Bogda-Oola, borders the great desert, and joins
Altai and the mountainous ridge which separates the basin of the
Arctic Ocean from that of the Pacific. To the southwest, Hindou-
Kouch, which prolongs Karakorum and is fully as high at-the begin-
ning, joins the chain of Elburs by the mountains of Korassan. To
the south, Soliman-Kouch stretches along the river Indus.
America. The orographic system of America forms a striking
contrast to that of Asia. Here there is no central group from which
diverging chains extend, like so many gigantic arms. On the con-
trary, a ridge, certain summits of which are dominated only by
those of the Himalayas, stretches along the shores of the Pacific
Ocean from Patagonia to Alaska. In the part farthest toward the
south, the Cordillera is simple and of moderate height; but towards
the north its average elevation gradually increases and reaches two
maximum points, in Bolivia and at the Equator. At the same time,
while its western side remains consistently abrupt, so that moun-
tains 6000 meters high are sometimes less than 20 leagues from the
sea, there appear on the eastern side foothills whose size constantly
increases, so that in Bolivia there is a group 100 to 150 leagues wide
with an average height of 4000 meters, in which there stand out
particularly two parallel chains bounding the lofty valley of the
lake of Titicaca (3915 meters) . These two chains, with their inter-
mediate valley cut by knots, where rise the Maranon and the
Ucayali, on which are built La Paz, Puno, Cuzco, Quito, and other
cities, first drop, spreading out to the knot of Pasco, then rise again
and reach their highest point just at the Equator. Here the eastern
ridge forks in its turn and ends at the sea, by the chain of Vene-
zuela and the Nevada of Santa-Marta, whose principal summit, the
Horqueta (5500 meters) , rises almost on the edge of the sea of the
Antilles.
The western Cordillera, considerably reduced in height, next
forms the isthmus of Panama, stretches along the Pacific in Central
America, rises again, and spreads out in Mexico. Thence extend,
as in South America, two great parallel chains, this time much
farther from each other, and much less lofty. On the east, the
ridge of the mountains of New Mexico, of the Rocky Mountains,
of the Mountains of the Chipways, separates the waters of the
Atlantic from those of the Pacific. The western chain remains near
Lofty Regions of the Globe 13
the ocean, and is interrupted in its course to allow free passage for
the Colorado and the Columbia.
Along the immense extent of this mountainous ridge rise moun-
tains, mostly volcanic, of prodigious height. Canon Bourrit seems
to us extremely impertinent when he maintains that "compared to
the Swiss Alps, these mountains of South America are only dwarfs
mounted on great pedestals"; 7 there is, however, a basis of truth
in what he says and this is interesting for our purpose.
Precisely at the equator, from the terraces of the city of Quito,
the astonished eye beholds eleven volcanic mountains covered with
eternal snows. Some, like Cayambe (5950 meters), Iliniza (5250
meters), Chimborazo (6420 meters), are now extinct; others, like
Pichincha (4860 meters), Antisana (5880 meters), and Cotopaxi
(5945 meters), still send forth smoke or flames. Chimborazo has
long been considered the highest peak of the Andes; that is a mis-
take. Higher still are Aconcagua (6835 meters) in the Andes of
Chile, and especially Illimani (7310 meters) and Sorate (7560 me-
ters), which border on Lake Titicaca.
A host of mountains, such as Tolima (5525 meters) and Purace
(5185 meters) in Colombia; Cotocachi (4950 meters), Sangay (5044
meters), Sinchalagua (5200 meters), Tunguragua (5020 meters),
Llanganati (5395 meters), Altar (5240 meters), Sara-urcu (5140
meters), in the Republic of Ecuador; Misti (6100 meters), Chipicani
(6180 meters) , Jachura (5180 meters) , Tacora (5700 meters) , Pari-
nacota (6330 meters), Nevado Vilcanota (5360 meters), Lirima
(7470 meters), in Peru; Sahama (7015 meters), the peak of Fari-
nacobo (6714 meters), Gualatieri (6690 meters), Cerro de Potosi
(6620 meters), Atacama (5300 meters), Coolo (6870 meters), Soo-
lolo (6795 meters), Quenuta (6870 meters), and Pomarape (6580
meters) in Bolivia; Nevada de Famatina (5820 meters) , in the Ar-
gentine Republic; Cerro del Plomo (5435 meters), Cima del Merce-
dario (6800 meters), Juncal (5960 meters), Tupungato (6180 me-
ters), Maypu (5385 meters), San Jose (6100 meters) in Chile, are
far higher than the Alps or even the Caucasus.8
The passes crossed by travelers going from the Pacific coast to
the great cities of the Cordillera or directly to the basins of the
Orinoco, the Amazon, or the La Plata, always reach at their highest
points altitudes capable of affecting the organism. The great road
which the Incas had constructed from Cuzco to Quito crosses the
pass of the knot of Assuay at 4735 meters; from Potosi to La Paz,
the traveler remains constantly at heights of 4000 meters and more;
the post-house of Talapolco is at an altitude of 4190 meters. In
] 4 ■ Historical
the Republic of Ecuador, the passes through which one can go
from Quito to the sea are above 4000 meters; the road from Lima
to Pasco passes at Alto de Lachagual at a height of 4710 meters;
that from Lima to Tarina, at 4800 meters. In Peru, the pass of
Vilcanota, between Cuzco and the sea, is at a height of 4425 meters;
the road from Arequipa to Puno passes at 4750 meters; the post-
house of Ancomarca, between Arica and La Paz, is 4330 meters
high; the pass of Qualillas 4420 meters high, that of Tacora 4390
meters, and that of Chullunquiani 4620 meters high. Finally, of
the two railroads which cross the Cordillera, the one which goes
from Puerta Mejia to Lake Titicaca has its highest point at Crucero
(4460 meters) ; thence it proceeds to Cuzco, remaining at a height
between 3500 and 4300 meters; the one last constructed, between
Callao and Oroya, passes at a height of 4760 meters, through a
tunnel which had to be excavated at almost the height of Mont
Blanc.
But the road most frequented by travelers till now in going
from one ocean to the other, was the one which crosses the Andes
from Mendoza to Santiago. It runs from Buenos Aires to Val-
paraiso (417 leagues), and from either of these points gives easy
access by sea to other ports of the Atlantic or Pacific. There are
four passes, which are, from north to south: that of "Los Patos,"
from Cordova to San Juan, long abandoned; that of Cumbre of
Uspallata, more frequented (3920 meters) ; and that of Portillo,
which requires the crossing of two passes, one of which has an
altitude of not less than 4360 meters. Finally, the last, which is the
lowest in the Andes in Chile, that of Planchon, which goes straight
to the port of Conception, reaches the altitude of 2500 meters.
Over the long extent of Central America, the Cordillera remains
at an average height; among the innumerable volcanoes with which
it bristles, that of Acatenango (4150 meters) in Guatemala, alone
exceeds 4000 meters.
The city of Mexico, like the city of Quito, is surrounded by
mountains: Coluca (4580 meters), Ixtaccihualt (4790 meters),
Chicle, over which Robertson junior passed in a balloon, and Popo-
catepetl (5420 meters). Citlaltepetl or the peak of Orizaba (5400
meters) is about 60 leagues away.
In the Rocky Mountains we should note particularly Uncom-
pahgre Peak (4430 meters) ; Pike's Peak, on the summit of which
(4340 meters) a meteorological observatory has just been installed;
Mount Lincoln (4300 meters) ; Long's Peak (4310 meters) and Fre-
mont Peak (4130 meters) , between which the great railroad from
Lofty Regions of the Globe 15
New York to San Francisco passes at an altitude of 2500 meters;
side by side, Mount Brown (4850 meters) and Mount Hooker (5100
meters) . The mountains along the Pacific make way for the Oregon
between the Sierra Nevada in California, the highest summits of
which are Mount Whitney (4500 meters), Mount Tyndall (4380
meters), and Mount Shasta (4400 meters), and the chain of the
Cascades, with Mount Baker (3390 meters), Mount Hood (3420
meters) , and Mount Rainier (4400 meters) as the highest peaks.
At the northern end, on the very shore of the ocean, rise the
highest peaks in North America, Mount Fairweather (4620 meters)
and Mount Saint-Elias (5440 meters) . Finally, in Alaska, the vol-
cano Gorjaloja ends the immense American chain, which has
stretched for more than 4500 leagues.
Africa. Africa is far from possessing chains of mountains which
can compare with the Himalayas, the Andes, or even the Alps.
And yet the belt of mountains at a short distance from the sea,
which surrounds the vast plateaux of the interior, rises at different
points to considerable heights. The Atlas range, which in French
and Tunisian possessions never reaches 3000 meters, exceeds this
height sometimes in Morocco, where Mount Miltsin measures 3470
meters. In Abyssinia, the circle of mountains around Gondar and
Lake Zana rises at certain points to 4425 meters (Abba-Jaret) , even
to 4620 meters (Raz-Daschan) ; the pass of Buhait is 4520 meters
high. On the shore of the Atlantic, the peak of Fernando-Po rises
to 3260 meters, and opposite it, the Kamerun Mountains, perhaps
the Bdav {6xwa) °f Hanno, reach to 4000 meters. In the colony of
Natal, the chain of Drakenberg displays summits more than 3000
meters high: Cathkin Peak (3150 meters) . Finally, almost on the
equator, near the shore of the Indian Ocean, the Kenia mountains
are 5000 meters high, and Kilimandjaro raises its crest, clothed in
perpetual snow, to 6110 meters. Let us add that in the interior a
lofty mountain has been noted, the peaks of which are more than
3000 meters high; it is Alantika, which is connected to the Kamerun
Mountains.
Islands. The islands, which remain to be discussed, contain only
a small number of mountains the height of which is great enough
for their ascent to bring on physiological disturbances. The highest
point of the Australian Alps, Mount Kosciusko, is only 2190 meters
high. But in New Zealand, several exceed 3000 meters, and the
giant of the southern island, Mount Cook, is 3770 meters high. New
Guinea contains several volcanic mountains which are no less lofty-
than those of New Zealand; the Owen Stanley range, the highest,
16 Historical
measures 4020 meters; but I object to including among them this
Mount Hercules, 10,929 meters high, the discovery of which an
English captain, M. Lawson, very recently announced, and on which
he claims to have ascended to 8435 meters. In the island of Hawaii,
among several still active volcanoes, Mauna Loa is 4250 meters
high, and Mauna Kea 4195; on the neighboring island of Maui,
Mauna Haleakala reaches an altitude of 3110 meters. The innumer-
able volcanoes which form the island of Java also have lofty sum-
mits; Gounong-Simeron measures 3300 meters, Semeroe 3730 me-
ters. In Sumatra, I will mention Indrapura (3870 meters) and
Dempo (3300 meters); in Borneo, Kini Ballu (4175 meters). The
mountainous ridge of Formosa has summits of 3000 to 4000 meters.
In Japan, among other lofty mountains, the volcano Fujiyama, the
"Unequalled Mountain," with its height of 4320 meters dominates
the roadstead of Yeddo. Finally, at the South Pole, the lofty vol-
canoes of Victoria Land, Erebus (3800 meters), Melbourne (4500
meters), and on the north Polar Circle, those of Kamchatka, the
highest of which is Klioutchef (4805 meters), end this volcanic
girdle which edges the Pacific Ocean on all its circumference, Amer-
ican or Asiatic.
On the island of Ceylon, the peak to which the pilgrims come
to worship the Cri-Pada, the print of the foot of Buddha or Adam,
rises only to 2420 meters. The mountains of Madagascar reach 3350
meters, at their highest point, Ankaratra. Piton de Neige, on
Reunion, measures 3070 meters. Finally, mention of the volcanoes
of Teneriffe (3715 meters) and of Etna (3310 meters) ends this
long list of all the places on earth the elevation of which is great
enough for an ascent of them to cause physiological disturbances
the severity of which necessarily attracts the attention of travelers.
Summary. All of the foregoing can be summarized rapidly in
a striking form. Let us suppose that the quantity of water on the
earth should increase enough so that the sea level would rise 3000
meters. What would remain, emerging above an almost limitless
ocean
The largest stretch of land would be formed by the high pla-
teaux of Thibet, Vokan, and Pamir, from which would rise numer-
ous mountains 4000 to 5000 meters high; its area would be two or
three times that of France. From it would diverge series of islands
which would mark the chains of Thian-Shang, Indou-kouch, and
Soleiman, and the mountains of Yunam and China.
At the other end of a terrestrial diameter, a long strip extending
from the equator to the Tropic of Capricorn, spreading out at its
Lofty Regions of the Globe 17
two ends and particularly towards the south, in the region corre-
sponding to Bolivia, would be prolonged towards the south and the
north by strings of lofty islands, crowded against each other; that
is all that would be left of the Andes.
The plateau of Armenia, separated from the emerging crests
of the Caucasus, would form the last bit of land, much smaller than
the other two, which would be flanked by a few summits of the
Taurus and the Elburs mountains.
Then the region of the Alps would have become a compli-
cated archipelago, with innumerable isles and islets, Oberland,
Grisons, the main range of Monte Rosa and that of Mont Blanc.
Of the Pyrenees there would remain only a few peaks near the
Maladetta. Mulahacen and Etna alone would be the only others
still emerging in Europe.
In Africa, there would be only the Abyssinian crescent and
isolated points: a few islands in the Moroccan Atlas, the Peak of
Teneriffe, that of Fernando-Po, the Kamerun Mountains, Kilimand-
jaro and Kenia, some peaks of the Drakenberg, and Ankaratra in
Madagascar.
North America would still have left above the waters a certain
number of summits belonging to the volcanoes of Guatemala and
Mexico, to the Rocky Mountains, to the Cascades, and the Sierra
Nevada; further to the north, Mount Saint Elias and the volcanoes
of Alaska, facing those of Kamchatka. Finally, of Oceania which
would have disappeared there would remain only the volcanoes of
the southern lands, New Zealand, Haiti, New Guinea, the islands
of the East Indies, Formosa and Japan.
These are the regions, thus reduced in surface, the study of
which .concerns us here. The survey we have made of them shows
that these mountains differ from each other greatly, not only in
their height, but also in their general character. Some rise rapidly,
with a single rush, so to speak, to their full height; this is the type,
for example, of the mountains of the islands and those of the west-
ern slope of the Cordillera of the Andes. In others, the strata are
heaped progressively upon each other, and summits of prodigious
height do not seem, because of their high bases, to equal isolated
peaks which they really surpass. In the third part of this book,
we shall show that these different orographic characteristics are
very important in our study.
Eternal Snows. The latitude of these mountains has an equal
importance. In fact, it is closely connected with the question of
18 Historical
temperature. Now the line at which the eternal snows begin cor-
responds very accurately with the temperature.
In our Alps and Pyrenees, about 43°-47° north latitude, this
line is a little above 2700 meters; on Etna (38° lat. N.) it rises to
2900 meters. In the main mountain ranges of the center of Asia, of
Pamir (40° lat. N.), in the mountains of Boutan (27° lat. N.) , it
varies between the enormous heights of 4000 to 6000 meters, higher,
naturally, in the regions nearest the equator, and also, curiously
enough, on mountain slopes facing north; on Gaurisankar, the
snow begins at 5300 meters towards the north, whereas towards
the south it begins at 4900 meters; the chain of Karakorum is at
certain points bare of snow up to 6500 meters (Schlagintweit) . In
Abyssinia (13° lat. N.) the line is about 4300 meters, and on Kili-
mandjaro (3° lat. S.) it is a little more than 5000 meters. The Cor-
dillera, in its long extent from south to north, does not lend itself
to an average estimate. At the equator, the volcanoes around
Quito have the line of eternal snow at about 4800 meters. Speak-
ing generally, this snow line is lower as the distance from the
equator becomes greater; at Popocatepetl (19° lat. N.), it is only
4300 meters. But in the Andes of Bolivia, and especially in the
mountains which edge Lake Titicaca on the west (16° lat. S.), it
rises considerably up to 6000 meters: much above the level in the
mountains of the east, where it is about 4800 meters. In the Andes
of the Chilean shore, on the volcano Corcobado (2290 meters) , in
43° lat. S., that is, at the same distance from the equator as Mala-
detta, it is only 1800 meters. On Mount Hooker (52° lat. N.) it is
2600 meters, on Mount Elias (60° lat. N.) 1500 meters, and on Baren-
Berg (2096 meters) on the island of Jan Mayen (71° lat. N.) at
only 400 meters. On Tierra del Fuego, on Mount Sarmiehto. (2075
meters), in 54° lat. S., the line is at 1100 meters, much lower than
on Mount Elias, which, however, is much nearer the pole.
Living Organisms. The extent of vegetation varies in altitude
with the snow line, which perpetually limits it. Whereas in our
Alps the timber line is at about 1800 meters, in the tropical Andes
the grapevine, the cinchonas, and the oaks extend up to 3000 meters.
In the Himalayas, the limit is higher yet, because apricot trees are
cultivated at an altitude of more than 3000 meters, and birches
and poplars grow up to an elevation of 4200 meters.
Animals naturally follow vegetation; birds conform to this rule,
and if on the sides of Chimborazo the condors sometimes soar at
the prodigious height of 7000 meters, that is because 2000 to 3000
Lofty Regions of the Globe 19
meters lower, pastures stocked with llamas, ostriches, etc., assure
them abundant food.
Human dwellings obey the same law. In central Europe, only
a few villages are at a greater altitude than 1500 meters; the high-
est in the Pyrenees, Porte, is at an altitude of 1625 meters; Saint-
Veran, in the Upper Alps, and Soglio, in the Rhetian Alps, are 2050
meters high. Above that height, there are only a few chalets un-
occupied in winter. The monastery of Saint Gothard is at an alti-
tude of 2090 meters, that of Bernina at 2300 meters; the highest
of the summer pastures to which the Alpine shepherds go is that
of Fluhalpe, at 2550 meters, and we know that a sufficient number
pf monks can be kept at the monastery of the Grand Saint Bernard
(2470 meters) only by means of the double attraction of heavenly
rewards and fat Italian prebends promised to the monks after some
years of painful sojourn on the mountain.
In the Rocky Mountains, Central City is at an elevation of
3460 meters on the side of Long's Peak (40° lat. N.).
In the Andes, not only villages but also populous cities are built
in large numbers in lofty places. Mexico City is at 2290 meters,
Santa Fe de Bogota at 2560 meters, Quito with its 60,000 inhabit-
ants at 2910 meters, Cuzco at 3470 meters, Micuipampa at 3620
meters, La Paz at 3720 meters, Puno at 3920 meters, Tacora at 4170
meters; Potosi, which formerly had more than 100,000 inhabitants,
is at 4165 meters, Oruro at 4090 meters, Torata at 4175 meters,
Portugalete at 4290 meters, Cerro de Pasco at 4350 meters; in Peru
and Bolivia, the larger part of the population lives above 3000
meters.9 Villages and dairy farms are at still higher levels. The
mines of Chouta are operated at 4480 meters, those of Huancavelica
at 4655 meters, those of Villacota at 5042 meters (Pissiz) . The post-
house of Rumihuani, on Illimani, is at 4740 meters. The railroad
from Arequipa to Puno, as we have seen, crosses the Cordillera at
an elevation of 4460 meters, and that from Callao to Oroya at its
highest point has a tunnel at 4760 meters; now these gigantic feats
required the prolonged sojourn of a great number of workmen.
In the Himalayas, man has established his dwelling at heights
just as astonishing. According to the Schlagintweit brothers, the
capital of Little Thibet, Leh, is built at 3505 meters; in the same
country, Muglab and Kibar, cities built of stone, are at 4150 and
4220 meters; the village of Chushul, highest in the Himalayas among
those which are inhabited all year long, is at 4390 meters; the
Buddhist monastery of Hanle, in Ladak, is at 4610 meters; about
twenty lamas live there. The villages inhabited only during the
20 Historical
summer are frequently situated between 4500 and 4900 meters;
Norbu, for instance, is at 4860 meters. In summer, the herds feed
in pastures as high as 5000 meters, like that of Larsa, at 4980
meters.10 On the high plateaux of Vokhan and Pamir, the Kirghiz
bring their yaks and sheep to the elevation of 4700 meters. The
Mirza sent by M. Montgomerie to Thibet even mentions a village,
Thok-Djalank, at the extraordinary height of 4980 meters.
The Andes and the Himalayas include the only two regions of
the earth where populations numbering millions of souls live
regularly above 3000 meters. On the lofty plateaux of Mexico, the
regions inhabited by a great number of men are as low as about
2000 meters; in Abyssinia, they are lower yet; Gondar is at 2220
meters and the village of Endschetkab, which seems to be the
highest in Abyssinia, at 2960 meters.
About the same thing is true of the mountain dwellers in
Armenia: Ispahan is situated at 1340 meters, Erzeroum at 1860
meters and Kars at 1900 meters. In Europe, as we have seen, the
level is still lower.
Men who live at these heights are certainly in conditions very
different from those encountered at sea level. At 5500 meters, a
liter of air weighs exactly half as much as at sea level; at 3300
meters, a third less; at 2300 meters, a quarter less. Are these
special conditions helpful or harmful to the material or intellectual
development of man? I shall try to discuss this question in the
third part of this book. I must remind my readers, furthermore,
that slow, progressive influences, which the sojourn in lofty moun-
tains may exert on successive generations, will be given little atten-
tion. For these important questions in hygiene and politics, I refer
my readers to the noteworthy book of M. Jourdanet. In this work,
and especially in the part devoted to the discussion of historical
records, I shall deal only with sudden and evident symptoms caused
in men and animals by an abrupt and considerable change in alti-
tude and consequently in barometric pressure. And so in the fol-
lowing pages I shall refer to the accounts of travellers, generally
telling their own experiences.
I have divided this historical part into three distinct chapters.
The first contains the reports of which I have just spoken; I have
classified them by orographic regions and listed them chronologi-
cally. I certainly do not claim that this list is absolutely complete;
but I think I have omitted nothing that is really interesting.
In the second chapter the accounts of aeronauts are reported.
Finally, in the third I have arranged the laboratory experiments,
Lofty Regions of the Globe 21
carried out with the purpose of studying the effect of diminished
pressure, the theoretical interpretations which various physiolo-
gists have given a priori of the symptoms observed in mountain
ascents, and finally the explanations suggested by the travelers
themselves, with the popular opinions about these strange illnesses.
Of course in this chapter I stop at the discussions which my own
researches have aroused; my purpose is to show the state of
knowledge when I began my experiments. Finally, the last chap-
ter summarizes both all the data observed and all the theories
suggested.
'See, however, in Chapter III, the quotation from Bacon.
2 The altitudes which I give in this general review were taken generally
from the last edition of Stieler's Hand-Atlas. Those which I did not
find in this atlas were taken, for Europe, from the Orographie of Brug-
niere; for France, from the Geographie of M. Levasseur; for South
America, from the works of Pentland and M. Pissiz. I used also the
information furnished by the recent work of Berghaus (Hdhentajel
von 100 Gebirgsgruppen aus alien Erdtheilen, Geogr. Jahrbuch. 1874).
My intended purpose evidently does not require absolute precision;
therefore I did not hesitate to use some rather old documents; for the
same reason, I omitted the units in the altitude figures.
3 Strabo, Geography, Book VI, Chap. Ill, Section IX.
4 Ibid., Book IV, Chap. VI, Section IV.
6 See Schuechzer, Ovpeoupoirris Helviticus. Lugd. Bat., 1725.
0 Harcourt, On the Himalayan valleys: Kooloo, Lahoul and Spiti. Journal
of the royal geogr. soc, Vol. LXI, p. 245-257; 1871.
7 Nouvelle description des glacicres et des glaciers des Alpes, second
edition, Vol. II, p. 87. Geneva, 1785.
"Besides the sources indicated above in a note, for these altitudes I
borrowed frequently from Kloden, Handbuch der Erdkunde, Berlin,
1869, and from Stein, edition of Wappens: Handbuch der Geographie,
Leipzig, 1863-70.
9 Jourdanet, Influence de la pression de Vair sur la vie de Vhomme, Vol.
I, p. 108. Paris, 1875.
10 Schlagintweit, Results of a scientific mission to India and High Asia in
1854-1858. 3 vol. 1861-1863; Vol. II, p. 477.
Chapter I
MOUNTAIN JOURNEYS
1. South America.
It is to the accounts of travellers who followed .the first Amer-
ican conquerors that we owe our knowledge of the discomforts
that attack man when he reaches a certain height on a mountain
side. To gain this elementary information, science had to wait
until Cortez attacked Mexico in 1519 and until Pizarro, twenty-five
years later, took Quito and conquered Chile and Peru. And yet
the conquerors themselves gave little heed to the increase of suf-
fering brought them by an unknown disease; at least their his-
torians do not mention it. In the account of the two expeditions
which by order of Cortez ascended to the crater of Popocatepetl
(5420 meters) in 1519 and 1522, the details of the second of which
were told by Herrera,1 mountain sickness is not very clearly indi-
cated.
The companions of Francis Pizarro (62 horsemen and 102 foot-
soldiers), in the daring march which took them in October, 1532,
from the Pacific coast to Cuzco, the heart of the empire of the
Incas, had to cross the lofty passes of the Cordillera ol the Andes
through a thousand perils. The historian, Xeres,2 who is the nar-
rator of this marvellous expedition, speaks only of "the great cold
experienced on these heights". However, they were below the
region of perpetual snow; the ground was covered with a plant
like the "esparto corto" (page 65) . Ferdinand Pizarro, sent by his
brother from Caxamalca to Parcama and Xauxa, on March 3, 1533,
passed over "a very steep mountain of snow, into which the horses
sank up to their bellies" (page 157) ; but mentioned no special com-
plaint.
In 1534, Pedro de Alvarado with 500 men and 225 horses under-
took the conquest of Peru; disembarking at Cape San Francisco, he
22
Mountain Journeys 23
reached the road from Cuzco to Quito at a point south of Ambato;
it is evident then that he crossed the Andes near Chimborazo. He
must have ascended to an altitude of more than 4800 meters, since
he was in the midst of snows; the sufferings of his army were
terrible:
There died (according to Herrera) fifteen Spaniards and six women,
several negroes and two thousand Indians. When they issued from the
snow, their faces were death-like. Several Indians who escaped lost
their toes and even their feet; some were blind.
The great expedition of Don Diego d'Almargo, in the conquest
of Chile, had still more terrible results. Leaving Cuzco in 1535, he
tried to cross the mountain, in spite of his captains. The Inca Gar-
cilasso de la Vega3 has given a touching account of the sufferings
of the army.
As the land they entered was so wild, suffering soon resulted: for
a few days after, they found strange obstacles in the road they took.
The first was that they could not walk on account of the snow . . . the
second, that food began to fail . . . and the third, that, according to the
calculation of the cosmographers and the astrologers, since the moun-
tains raised their summits into the middle regions of the air, the tem-
perature was so low, because everything there is covered with snow,
particularly in such a season as our adventurers had chosen, namely,
winter when the days are the shortest and coldest of the year, that
many Spaniards, Negroes, Indians, and horses were frozen and be-
numbed. But the Indians, though lightly clad, had the best of it.
Of the 15,000 of them, morethan 10,000 died and more than 150 of the
.Spaniards , . . .
It was probably in the lofty regions of Tacora, on the road be-
tween La Paz and Arica, that this expedition took place, so un-
fortunately undertaken in the middle of the southern winter.
In 1541, i shortly after the death of Pizarro, four Spaniards, who
were part of an expedition which had left Asuncion at the order
of Irala, went to Lima, passing by Potosi and Cuzco. An envoy of
the governor of Peru had made the same journey; "Miguel Ruedo
and Ahaic were so exhausted by the hardships of the journey,"
says Ulrich Schmidel, who accompanied the expedition, "that they
were obliged to stop at Potosi" (page 222) .
These accounts, as we see, give as explanation of the sufferings
and disasters only fatigue, lack of food, and cold. The Jesuit
father Acosta,5 who travelled in South America about the end of
the sixteenth century, was the first to note the special distress due
to a special cause, the air of lofty places. Let us add that he gave
a striking description of it.
24 Historical
From the translation printed in Paris in 1596 by Robert Renault
Cauxois, I copy the most interesting part of his account.
In certain parts of the Indies, the air and the wind blowing there
dizzy men, not less but more than at sea ....
In Peru there is a high mountain called Pariacaca, and having
heard tell of the variation it caused, I went there, prepared the best I
could according to the information given by those called Vaquianos or
experts; but in spite of all my preparation, when I began to mount the
stairs, as they call the highest part of this mountain, I was suddenly
attacked and surprised by an illness so deadly and strange, that I was
almost on the point of falling from my horse to the ground, and al-
though there were several in our company, each hastened his step
without waiting for his companion so that he might leave this evil
spot quickly. Being left alone then with an Indian, whom I asked to
help me sit on my horse, I was seized by such a spasm of panting and
vomiting that I thought I should give up the ghost. After vomiting
food, phlegm, and bile, one yellow and the other green, I next threw
up blood, so that I felt such distress in my stomach that I can say if it
had lasted I am sure I would have died. That lasted only three or four
hours until we had descended pretty low and had reached a tempera-
ture more suited to nature, at which point our companions, about
fourteen or fifteen in number, were very much exhausted, some of
them asked for confession on the road, thinking they were really going
to die, others dismounted and were wrecked with vomiting and diar-
rhea; I was told that in the past some had lost their lives from this
distress. I saw a man lying on the ground in a passion, crying out
with the rage and pain caused him by this passage of the Pariacaca.
But usually it does no important harm, except this annoying and dis-
agreeable trouble as long as it lasts. And it is not only the pass of
Mount Pariacaca that has this characteristic, but also this whole chain
of mountains, which extends more than five hundred leagues; no mat-
ter where one crosses it, he feels this strange distress, although it is
worse in some places than in others, and worse in passes up from the
seashore than in those from the plains. I myself crossed it, besides by
Pariacaca, by Lucanas and Soras, and in another place by Colleguas,
and in another by Cauanas, that is, by four different places in my
various comings and goings, and always in this place, I felt this dizzi-
ness and distress that I have mentioned, although never as much as the
first time at Pariacaca, and all who have passed that way have had the
same experience. . . .
Not only men feel this distress, the animals do too, and sometimes
stop so that no spur can make them advance. For my part, I believe
that this place is one of the highest spots on earth.
This whole chain of mountains is practically deserted, without any
villages or habitations of men, so that one can hardly find little houses
or retreats to lodge travellers at night. There are no animals either,
good or bad, except maybe a few vicunas, which are the sheep of the
country, which have a strange and marvellous characteristic, which I
shall mention in the proper place. The grass is often burned and
blackened by the wind I mentioned, and this desert lasts through the
Mountain Journeys 25
twenty-five or thirty leagues of the pass, and in extent stretches more
than five hundred leagues, as I said (page 87).
After he had made this description, and we will admit that
exactness could not have been joined to picturesqueness more skil-
fully, Acosta discusses the cause of these symptoms which he says
he experienced in four other crossings of the great Cordillera. We
shall report in a chapter devoted to a summary of theoretical ex-
planations the ideas of this reverend gentleman, ideas which are
really marvellous for insight and clearness.
It is hard to determine the exact point at which Acosta crossed;
Pariacaca is a name that has disappeared in Peru as well as in
Ecuador. It is almost certain that it was below the snow line, for
his account, so exact and so detailed, does not speak of the snow;
its height above sea level was therefore probably 4500 meters at
the most.
It is very strange to see that after describing so admirably and
after explaining the painful sensations he had experienced while
crossing the lofty mountains, Acosta does not consider them as
accounting for the disasters undergone by the Spanish armies. Yet
he knew them very well; he speaks of them; but here his clearness
of mind seems to abandon him.
There are other deserts or uninhabited places, which in Peru they
call Punas (to speak of the second point which we promised) where
the quality of the air cuts body and life from men without their feel-
ing it. In the past the Spaniards travelled from Peru to the kingdom
of Chile across the mountain; today they usually go by sea, and some-
times along the coast; and although this route is tiresome and incon-
venient, there is never as much danger there as on the mountain road,
in which there are plains in passing through which several men have
died and perished, and others have escaped with great luck, and some
of them were maimed. In this place there blows a little wind which is
not too strong or violent. But it is so penetrating that men fall dead
of it almost without feeling it, or maybe their fingers and toes are left
there; which may seem a fabulous tale, and yet it is a trUe thing. I
knew and long frequented General Hierosme Costilla, former adminis-
trator of Cusco, who had lost three or four toes, which had fallen off
when he passed through the deserts of Chile, because they had been
attacked and penetrated by this little wind, and when he happened to
look at them, they were all dead and fell off of their own accord
without giving him any pain, just as a rotten apple falls from the tree.
This captain related that of a good army which he had led through this
place the preceding years, since the discovery of this kingdom of Al-
magro, a great part of the men remained there dead, and that he saw
their bodies stretched out on the desert, without any bad odor or
decay. ... No doubt this is a kind of cold so penetrating that it ex-
tinguishes the vital heat by cutting off its power; and also because it
26 Historical
is very cold, it does not corrupt or cause decay in dead bodies, because
putrefaction proceeds from warmth and humidity (page 89).
A celebrated Spanish historian, who wrote shortly after Acosta,
Antonio d'Herrera, took up the ideas of the learned Jesuit, and,
without quoting him, copied almost in full the passages which we
have just put before our readers/' But it is evident that he could
not include the whole of the explanation of Acosta; at least it
would be useless to include here his chapter: Reasons why it is so
dangerous' to pass through the "Puertos Nevados" which lead to
Chile, and the passes of the province of Quito through which Belal-
cazar and Alvarado crossed with their armies.
A century and a half passed without the historians and the
travellers speaking of the physiological symptoms which Acosta
had noted. The "Lettres Edifiantes",7 in which there are so many
details, generally childish but sometimes interesting, do not allude
to them, although their writers were evidently several times in
the same conditions as their predecessor. My researches in the
authors of the seventeenth century have revealed nothing pertinent
to our subject.
But a document published at the beginning of the eighteenth
century shows us that in the Andes it had been known for a long
time that at certain points more or less severe symptoms attack
men and animals. We even find in this document an explanation
which recurs up to the present. A Frenchman, Frezier,8 visited
the coasts of Chile and Peru from 1712 to 1714; he speaks at length
of the rich mines in the interior of the country, and after discussing
the origin of the metals, he adds:
It is certain that strong exhalations issue constantly from the
mines; the Spaniards who live above them are obliged to drink very
frequently Mate, the grass of Paraguay, to moisten their lungs, and
thus prevent a sort of suffocation. Even the mules which pass through
these places, although they are much less rugged and steep than others
along which the mules run, are obliged to rest almost every moment
to regain breath. But these exhalations are much more evident within;
they are so powerful over bodies not accustomed to them that a man
who enters for a moment comes out as if crippled. . . . The Spaniards
call this illness Quebrantahuessos, that is, it breaks the bones (page
150).
Frezier had no opportunity to make personal observations. But
a few years later, in 1736, three French Academicians, Bouguer, La
Condamine, and Godin, went to Peru to measure a degree of the
meridian there. It was at the time of this celebrated expedition
that the symptoms of decompression were first studied and dis-
Mountain Journeys 27
cussed scientifically. In one of their trips, Bouguer and La Con-
damine remained three weeks on Pichincha, at an altitude of about
4860 meters. There they experienced discomforts which Bouguer '■'
describes in the following terms:
We were all at first considerably inconvenienced by the keenness
of the air; those of us who had more sensitive lungs felt the difference
more and were subject to slight hemorrhages, which no doubt came
from the fact that the atmosphere, since its weight was less, did not
by its compression help the vessels sufficiently to retain the blood,
which, however, was still capable of the same action. Personally I
did not notice that this inconvenience increased much when we hap-
pened later to ascend higher; perhaps because I was already accli-
mated, or perhaps also because the cold prevents the expansion of the
air from being as great as it would be otherwise. Several of us, when
we were ascending, fell fainting and were seized by vomiting; but these
symptoms were more the result of fatigue than of the difficulty of
breathing .... We sometimes felt a very severe cold, when the ther-
mometer indicated only a moderate degree (page 261).
Bouguer then expounds a hypothesis of which we shall speak in
the third chapter; according to him, the symptoms experienced are
due in part to fatigue, in part to a sort of scurvy.
In the two volumes which La Condamine1" devotes to the ac-
count of his journey, and which are anyway half filled by his vio-
lent disputes with Bouguer, I could find only the following pas-
sage referring to his stay on Pichincha:
Don Antoine d'Ulloa, while ascending with us, fell in a faint, and
had to be carried to a nearby cave . . . Personally I felt no difficulty in
breathing. As to the affections which M. Bouguer mentions and which
apparently refer to the tendency to bleed from the gums, with which
I was then inconvenienced, I think it should not be attributed to the
cold of Pichincha, since I felt nothing like it in other places of equal
altitude, and since the same symptom attacked me again five years
after at Cotchesqui, the climate of which is temperate. (Vol. I, p. 35.)
But the most circumstantial and exact information is furnished
us by Don Ulloa, a young naval officer whom the Spanish govern-
ment had sent to protect the French mission, and who later played
a great part in his nation. His accounts11 give at the same time the
story of the symptoms experienced temporarily by mountain climb-
ers, and those which are the consequence of a stay of several
months in certain regions of the Cordillera of the Andes. Here
also for the first time we find suggested the services which a sojourn
in lofty altitudes can render to therapeutics:
Those who are not accustomed to frequenting these places are also
exposed to another discomfort, besides the cold of which we have just
28 Historical
spoken; it is the Mareo of the Puna; and it is rare that they are not
attacked by it. It is a disease quite like that which one feels at sea:
it displays all the symptoms of it and follows the same course. The
head whirls; one feels very hot; and painful nausea comes on, followed
by bilious vomiting. Strength fails, the body weakens, fever appears;
and the only comfort one finds is in vomiting. Some people are even
so weakened that they would cause anxiety, if it were not certain that
the -trouble was nothing but this Mareo. That lasts usually one or two
days, after which health is restored. This inconvenience is greater or
less according to the natural constitution of the person; but few escape.
When anyone has felt it once, it is extraordinary that he should be
attacked by it again in passing by Puna or coming from low countries
or any country in which there is a high temperature (page 116). . . .
There is also observed in these climates another symptom to which
animals are subject. As soon as they pass from the plains to these
eminences or Punas, as from countries where there are dwellings to
the summits which surround them, breathing becomes so difficult for
them, that in spite of the different pauses they make to get their breath,
they fall and die there (page 118).
Ulloa then discusses the different explanations suggested in his
time to account for these phenomena, and energetically rejects the
idea of toxic emanations due to minerals buried in the earth, an
idea which is current even today among the common people and
even in the educated classes of Bolivia and Chile. Then he adds:
The men who have recently come to this climate also experience
something similar to what I said about animals; while walking, they
feel a suffocating and very painful fatigue, which forces them to rest a
long time; that happens to them even in the flat lands; now there can
be no other cause for this phenomenon than the keenness of the air;
but as the lungs become accustomed to this atmosphere, the discomfort
lessens. However, they still experience some difficulty in breathing
when they wish to climb some slope; this is inevitable, but is not felt
in other countries where the atmosphere has a regular density.
This lightness of the air is favorable to those who have become
asthmatic in a denser air. This asthma is known by the name of
ahogos or suffocation; it is rather common there; that is why those who
are attacked by it in the low countries go up into the mountains; al-
though they do not entirely recover there, they live there nevertheless
without pain: on the contrary, those who became so in high altitudes
are well in the lowlands; so change of air is a certain alleviation in this
sort of disease. The science of medicine might profit by these experi-
ences, sending the patients of one country into another, although
elsewhere there is not so great a difference of altitude.
Difficulty of breathing is noted also to a certain degree in the high-
lands of the province of Quito, but it is less painful there: no doubt
that is because one of these countries is on the equator, or nearly so,
whereas the other is remote from it. The conclusion is that the Punas
or summits of Peru are less cold and the air less cutting than in the
Mountain Journeys 29
other countries. But it is well to note that what has been said of
Guancavelica is general for all the lands extending towards the south.
That these details may be better understood, I shall observe here
that what is called Punas in Peru, is named Paramo in the kingdom of
Quito (page 120).
It was in the last year of the eighteenth century that the il-
lustrious Alexander von Humboldt undertook that great expedition
into South America, which was the source of so many important
discoveries in the history of man, the physics of the earth, and
natural history.12 In 1802 he made a stay on the lofty plateau of
Quito, overlooked by the gigantic peaks of Pichincha, Cotopaxi,
Chimborazo, and Antisana.
In March and in June 1802, he made ascents which have be-
come famous of the last two volcanoes; he immediately gave a brief
account of them in two letters, written the same day; I quote from
them passages which are interesting from our point of view.
The first is addressed to Citizen Delambre;13 it relates particu-
larly the ascent of Chimborazo:
It was believed till now in Quito that 2470 fathoms was the great-
est height at which men could resist the rarity of the air. In the month
of March 1802, we passed a few days in the great plains which sur-
round the volcano of Antisana, at a height of 2107 fathoms, where
cattle, when chased, often vomit blood .... On May 16, we explored a
path on the snow, a gentle slope on which we climbed to 2773 fathoms.
The air there contained 0.218 of oxygen . . . the Reamur thermometer
stood at only +13°; it was not cold at all, but blood issued from our
lips and eyes. (P. 174.)
In the expedition which I made June 23, 1862, to Chimborazo, we
proved that with patience one can endure a greater rarefaction of the
air. We crossed 500 fathoms higher than La Condamine at the Cora-
zon, and we carried instruments on Chimborazo to 3031 fathoms, seeing
the mercury drop in the barometer to 13 inches, 11.2 lines; the ther-
mometer stood at 1.3° above zero. Our lips bled again. Our Indians
abandoned us again as usual. Citizen Bompland and M. Montufar, son
of the Marquis de Selvalegre, of Quito, were the only ones who were
resistant. We all felt a discomfort, a weakness, a desire to vomit, which
certainly arises as much from the lack of oxygen in these regions as
from the rarity of the air. I found only 0.20 of oxygen at this immense
height. (P. 175.)
The other letter is addressed to his brother, Wilhelm von Hum-
boldt; in it, more than in the preceding letter, he speaks of the
ascent of the volcano Antisana: 14
On our journey to the volcano of Antisana, the weather was so
favorable that we ascended to the height of 2773 fathoms. At this alti-
30 Historical
tude the barometer fell to 14 inches, 7 lines, and the rarity of the air
made blood issue from our lips, our gums, and even our eyes; we felt
an extreme weakness, and one of those who accompanied us on this
journey fainted. . . .
We succeeded in approaching to about 250 fathoms from the sum-
mit of the immense column of Chimborazo. . . . We mounted to a height
of 3031 fathoms, and we felt inconvenienced in the same manner as on
the summit of Antisana. Even two or three days after our return
to the plain, we continued to feel a discomfort which we could at-
tribute only to the effect of the air in these lofty regions, an analysis
of which gave us 20 per cent of oxygen. (P. 329.)
Thirty-five years later,15 von Humboldt returned with details
about the account of these ascents. He dwells particularly upon
the physiological symptoms, and develops some very interesting
theories in this regard.
June 22, 1802, he was in the plain of Tapia, at an altitude of
2890 meters. The first part of the ascent had no particular inter-
est for our purpose:
At an elevation of 15,600 feet, all the Indians but one abandoned
us. . . . They claimed that they suffered far more than we did. There
were only four of us left then: M. Bonpland, . . . M. Carlos Montufar,
... a half-breed from San Juan, a nearby village, and I. (P. 413.) . . .
We all began by degrees to be very uncomfortable (they were
then at a height of about 5,000 meters) . The desire to vomit was ac-
companied by fits of dizziness and was much more painful than the
difficulty of breathing. The half-breed from San Juan, a poor and
sturdy peasant, who had wished to follow us to the end out of the
kindness of his heart and not from any selfish interest, suffered more
than we did. Our gums and lips bled. The conjunctiva of the eyes in
all of us without exception was bloodshot. These symptoms of extra-
vasation in the eyes and of a discharge of blood from the gums and lips
did not disturb us, because we were acquainted with them from many
examples. In Europe, M. Zumstein began to bleed at a much lower
elevation, on Monte Rosa.16 (P. 417.) . . .
Once, on the volcano of Pichincha, I felt, without any bleeding,
such a violent pain in my stomach, accompanied by vertigo, that my
companions found me stretched out unconscious on the ground. The
altitude was only 13,800 feet (4480 m.), and consequently not im-
portant. But on Antisana, at the great height of 17,022 feet (5527 m.),
Don Carlos Montufar bled profusely from the gums. All these phe-
nomena vary greatly, according to the age, the constitution, the deli-
cacy of the skin, and the previous muscular efforts which one has
made; however, they are for each individual a sort of measure of
the rarefaction of the air and the altitude he has reached. According
to my observations, they appear in the Andes in white men, when the
barometer stands between 14 inches and 15 inches 10 lines. (P. 418.)
We shall see later what successive opinions, and considerably
Mountain Journeys 31
different ones, the illustrious naturalist held about the explanation
of these various phenomena.
But before going on to other accounts, I should include here a
fragment of one of the works of Humboldt,17 in which he gives in-
formation full of interest for the subject of our study about the
usual habitat of the condor and the maximum height to which it
rises:
The region which one may consider the habitual sojourn of the
condor begins at a height equal to that of Etna, and includes layers of
the air from 1,600 to 3,000 fathoms above sea level. The largest speci-
mens found in the chain of the Andes of Quito have a wing-spread of
14 feet, and the smallest only 8 feet. By these dimensions and by the
visual angle at which this bird appeared sometimes perpendicularly
above our heads, one may judge to what prodigious height it rises when
the sky is clear. Seen, for example, at a visual angle of four minutes,
he would be at a perpendicular distance of 1,146 fathoms. The cavern
(machay) of Antisana, situated opposite the mountain of Chuesolongo,
and from which we took the measurement for the soaring bird, is
2,493 fathoms above the level of the Great Ocean. So the absolute
height which the condor attained was 3,639 fathoms; there the barom-
eter is hardly twelve inches high. It is a very remarkable physiological
phenomenon that this same bird, which for hours soars in circles in
regions where the air is so rarefied, suddenly swoops down to the sea-
shore, for instance, along the western slope of the volcano of Pichincha,
and thus in a few instants passes through all climates, as it were. At
a height of 3,600 fathoms, the aerial and membranous sacs of the con-
dor, which were filled in lower regions, . must be extraordinarily in-
flated. Sixty years ago Ulloa expressed his surprise that the vulture
of the Andes could soar at a height where the air pressure was only
14 inches. It was believed then, on the basis of experiments made with
the pneumatic machine, that no animal could live in a medium so rare.
As I have already stated, on Chimborazo I saw the barometer drop to
13 inches 11.2 lines. My friend, M. Gay-Lussac, breathed for a quarter
of an hour in air the pressure of which was only 0.3288 meters. At
such great heights, in general man finds himself in a very painful state
of asthenia. On the contrary, in the condor the act of respiration ap-
pears to take place with equal ease in media in which the pressure
varies from 12 to 28 inches. Of all living beings, this is certainly the
one which can at will rise furthest from the surface of the earth. I
say at will, because small insects are carried still higher by ascending
currents. Probably the height reached by the condor is greater than
we found by the calculation given. I remember that on Gotopaxi, in
the plain of Suniguaicu, covered with pumice stones, and at an eleva-
tion of 2,263 fathoms above sea level, I saw this bird at such a height
that it seemed only a black dot. What is the smallest angle at which
objects dimly lighted can be distinguished? The weakening of the rays
of light by their passage through the layers of air has a great effect
upon the minimum of this angle. The transparency of mountain air is
so great at the equator, that in the province of Quito, as I have shown
32 Historical
elsewhere, the poncho or white cloak of a person on horseback can be
seen with the naked eye at a horizontal distance of 14,022 fathoms, and
consequently at an angle of 13 seconds. (P. 78.)
The revolutions by which the Spanish colonies of America shook
off the yoke of the mother country resulted in the crossing by
troops of several thousands of men of certain passes of the Andes
usually frequented by only a few travellers. The stay in rarefied
air certainly brought an increase of suffering to these little armies;
but the historians seem to have paid but little attention to it, pre-
occupied as they are by the natural effect of the cold, the lack
of food, and the excessive fatigue.
Early in the year 1817, General Saint-Martin, at the head of
3000 Independents, invaded Chile by the difficult pass which leads
from Mendoza to Santa Rosa, the highest point of which has an
elevation of more than 4300 meters.
The expedition (says M. Gustave Hubbard 1S) presented such great
difficulties that the troops from Santiago and the governor of Chile re-
fused to give credence to such a dangerous attempt .... A great num-
ber of men perished from cold in the rarefied and frigid atmosphere
through which they had to pass .... When the army left Mendoza it
had 9,281 mules; only 4,300 were left on the other side of the Andes,
and out of 1,600 horses only 500 survived. (Vol. I, p. 346.)
The army which Bolivar led against Morillo in June 1819 from
Venezuela to New Grenada, across the Andes of Colombia encoun-
tered the same difficulties. The Englishmen who formed a con-
siderable part of his expeditionary forces died in great numbers.
The celebrated historian Gervinus says in this reference:19
The way is unmistakably marked by the bones of numerous vic-
tims who die during these crossings. ... In fact, those who, overcome
by weariness and cold, abandon themselves to the peculiar drowsiness
to which the traveller in lofty places becomes an easy prey fall into a
numbness which takes their strength from them (emparamados from
paramos, a name given to the highest plateaux) and delivers them over
to death without any hope of rescue (page 88).
Upper and lower Peru also witnessed such expeditions. In 1821,
the Spanish viceroy La Serna, forced to abandon Lima, retreated
across the Cordillera, and established himself in the high valley of
Jauja. Thence his troops often descended to attack the Independ-
ents, until Bolivar undertook against them the campaign which
ended in the battle of Ayacucho (1824), and the whole of which
was carried on at a height of more than 3000 meters. It was at a
still greater height, 4500 meters, that General Santa Cruz defeated
the Spaniards in 1822 on the slopes on Pichincha.
Mountain Journeys 33
The Spanish writer Torrente,20 in his history of the Spanish-
American revolution, is correct in attributing to the altitude a
considerable share in the sufferings of the armies during these
marches at high altitude:
When one crosses the Cordillera of the Andes of Peru, one usually
suffers from two maladies: spasms and nausea. The latter is more
common, especially for those who come from the low, hot land along
the coast. The keenness of the air in this atmosphere hampers respi-
ration and makes it very laborious, increases the pulse rate, speeds up
the circulation, produces intense headaches, and causes the blood ves-
sels to swell quickly, and the unfortunate victim to perish, with an
issue of blood from the mouth, the eyes, and the nostrils. It is true
suffocation which attacks animals also if their burdens are increased or
their pace hastened ever so little. The losses of the small army of the
viceroy La Serna were greater during the retreat from Lima to Jauja,
because a large number of his soldiers were still convalescing.
The author adds, repeating popular superstitions:
It seems that the veins of precious metals and antimony which run
through the territory of Peru are the cause of this atmospheric combi-
nation which is so injurious to health. What would tend to prove it is
the fact that its effects are much less noticeable on points of greater
altitude, such as certain parts of the Cordillera of Chile, the Sierra of
Pichincha, and other mountains of Quito.
This nausea is known in the country by the name of Soroche, and
it is experienced even in certain low lying villages, situated in metalli-
ferous localities. (Vol. Ill, p. 164 and 169, note.)
We have seen Saint-Martin crossing the Cordillera from Men-
doza to Santiago, thus carrying out an expedition which Manuel
de Almagro 21 considers "as far more difficult and worthy of ad-
miration than that of Bonaparte at the Grand Saint-Bernard, which
has been much exaggerated" (p. 34) . This route, as we have said,
is the one usually followed by travellers who wish to cross Amer-
ica. Two passes exist, one by Cumbre (3920 meters) , the other by
Portillo (4360 meters). The former is more frequented. Most
accounts mention the symptoms of decompression; but on this road
they are usually not serious.
However, Samuel Haigh,22 who ventured into the passes of
Cumbre from Mendoza to Santiago during the austral winter of
1818, felt them considerably. A snow storm which assailed him
compelled him to take refuge with his companions at a hill where
the "casucha" of Las Vacas offered them a shelter:
While climbing the hill on which it is built, (he says) I was at-
tacked for the first time by the puna or soroche. This is an illness
peculiar, I think, to high mountains; it is the result of the extreme
34 Historical
rarefaction of the air which therefore causes difficulty in breathing.
Three times I was forced to lie down on the ground before reaching the
top of the hill, and I experienced shortness of breath with pain and op-
pression in the chest and a sensation of nausea. The puna attacks some
persons so severely that blood issues from their mouths and nostrils.
However, I must say, our sufferings really began. (P. 104.)
But all are not equally affected, especially when, as usually
happens in the favorable season, the journey is made on mule-
back. Miers,23 who crossed in May 1819, explains this very well:
Those who wish to undertake this journey will be dismayed t>y
the accounts of the difficulties caused by the puna, a name given to
the sensation of short and difficult respiration, which often attacks us
when we ascend into rarefied air. This is the terror and the subject
of conversation of all who have crossed the Cordillera, who tell you
that they escaped these terrifying symptoms only by eating a great
many onions, and by tasting no alcoholic liquors, except wine, which is
considered the antidote of the puna. These precautions, however, are
not necessary, for very few persons who make the ascent on horseback
experience this discomfort, except those who have a lung ailment; but
many of those who have climbed Cumbre on foot, overexerting them-
selves in driving the mules, have been affected. I do not think that
anyone would suffer much from the puna unless he overexerted him-
self. I have twice ascended and descended Cumbre on foot without
being affected. Moreover neither my wife nor my child, only six
months old, felt the least difficulty in breathing with the thermometer
at 35°F. and the barometer at 19 and Vs inches, although we might
have expected that in a child of this age with such delicate lungs one
would first observe modifications in respiration, even though they were
due only to excessive rarefaction of the air. (Vol. I, p. 321.)
The account of the Scotchman Caldcleugh -4 is particularly inter-
esting, because this traveller crossed the Andes twice in opposite
directions. The first time, March 17, 1820, in very bad weather, a
snowstorm, he crossed by Portillo and Piuquenes, going from Men-
doza to San Jose. He does not mention any symptoms. (Vol. I,
p. 285—323.)
But on June 2 of the following year, while going from the Punta
of San Luis to Cordova (Argentine Republic), he crossed at a
much lower point, the Sierra of Cordova. He stopped at a little
hut at an elevation of 3200 meters and passed the night there. The
next day, ascent of the pass:
The snow was frozen hard. . . . Two of the peons suffered severely
from an illness called puna, which attacked them shortly after we had
left the hut. This illness seemed to me to consist of heavings of the
diaphragm, accompanied by great exhaustion and loss of spirits. Those
attacked by it lie down, give themselves up, and often die before
reaching the descent. Great quantities of garlic and onion are con-
Mountain Journeys 35
sidered specific against this condition. But the surest treatment is to
take the patients as quickly as possible to a less lofty place. It has
been commonly noted that those of the peons who are old and addicted
to bad habits suffer more from the puna than the others, and this note
applied perfectly to the two whom I had to send back. One of them
was extremely sick, and the other under whose care he departed was
slightly affected. At present I do not know whether he managed to
cross the valley.
Shortly afterwards they reached the summit, at an elevation of
3840 meters. He suffered no personal distress.
Schmidtmeyer,25 in the account of his crossing the Cordilleras
from east to west by the volcano of Cumbre, speaks of no physiolog-
ical symptom. But at the end of the book, he fills this gap:
I should have spoken sooner of this exhaustion accompanied by
difficulty in breathing which one experiences when crossing the range;
I often heard it spoken of in Chile. But we remained on muleback up
to the highest point of the pass, which we therefore reached without
the slightest effort. One of our men, however, suffered from it con-
siderably, but I do not know whether it was an extreme case. Usually,
on the high peaks of the Andes, one experiences great difficulty in
moving; that is the opposite of what happens on other mountains.
(P. 349.)
Proctor -° (1824), Head27 (1825), who followed the same route,
in the same direction, make absolutely no mention of the puna.
Lister Maw,2S who in November 1827 left Truxillo (Peru) for the
basin of the Amazon, does not speak either of the effect of the
pressure, except at Contumasa (2190 meters) , where he says po-
etically:
The rarity of the atmosphere tended greatly to raise our spirits.
But Lieutenant Brand 29 is more explicit; he mentions these
symptoms, and even tries to explain them, but without having
experienced them himself, and yet he made his first journey from
Mendoza to Santiago over Cumbre in the midst of the austral
winter (August 22, 1827), He had to endure terrible cold, even
down to 15° below zero.
August 22, he ascended Cumbre; the thermometer stood at
34° F.:
As I had often heard of the puna, or difficulty in breathing, from
travellers who complained of it bitterly, I gave particular heed to it;
I cannot say that I felt any more inconvenience than would have hap-
pened to me if I undertook such labor, so long continued, even if I
, had not been at this elevation. I suffered only from a very acute
thirst, which the snow aggravated instead of satisfying. . . . But I do
not intend to contradict what has been said of the puna, which has
assailed many travellers severely. (P. 147.) . . ,
36 Historical
On my return across the Andes, in December, 1827, I saw that the
mules stopped frequently to breathe, especially when climbing Cumbre,
where they stopped at each zigzag, as if they suffered from pain in the
lungs, and, like Acosta, I found that neither shouts nor blows could
make them advance until it suited them. But that is not peculiar to
Cumbre or to the other mountains of the Cordillera, for mules often
stop thus, as if they felt pain in their lungs.
It happened likewise to the peons, who suddenly, while walking,
stopped, shouted "puna, puna" and then continued ascending. It
seemed as if they knew the places where this would happen to them
when on foot, for they frequently said: "Here there is much puna."
I can attribute this only to the existence in these places of minerals
which alter the air more or less, whence comes their effect upon the
lungs. (P. 149.)
The French officer De la Touanne,'0 who took part in the ex-
pedition of Bougainville, and who followed the same route as
Brand, was so severely attacked as to fall on the ground; he
crossed the pass January 29, 1826.
I estimated that the point where we were is at least 2,000 fathoms
high. . . . The air is very much rarefied at this elevation; I had dis-
mounted from my mule, letting him go ahead with the caravan, and I
was examining some stones at the right and the left of the path. When
I afterwards wished to increase my pace to overtake my travelling
companions, respiration suddenly failed me; I fell down, my chest
oppressed and breathing with difficulty. A peon had to bring me my
mule; and from these slight symptoms I could judge what the arrieros
and the travellers who have to cross this pass in bad weather must
suffer. (P. 50.)
After this testimony from travellers who only crossed the moun-
tain, here is what is said by an English engineer, Ed. Temple,-1 who
lived for a year 1826-1827, at Potosi (4165 meters), where he was
employed in the exploitation of the rich mines of that country:
While walking, I often experienced that difficulty in breathing
which is caused by the extreme rarity of the air, and to which even
the natives and the animals are subject. The royal sport of horse rac-
ing cannot take place here, for the horses seem to suffer more from the
zorochi than men do; I have often heard that they fall and die, if they
are hurried when they are climbing a hill. (Vol. I, p. 296.)
I shall also quote the passages in which the English traveller
Bollaert,'12 who in the month of June, 1827, ascended the mountain
Tata Jachura (5180 meters), describes the sufferings he experi-
enced during the ascent.
We had slight nosebleeds, buzzings in the ears, headache, dimness
of vision, and our bodies were numbed by cold, all of which were
caused by the puna or soroche, that is, the expansion and cold of the
atmosphere. (P. 121.)
Mountain Journeys 37
I now come to the important journey of d'Orbigny 33 and the in-
teresting description he gives of mountain sickness.
In his first journey, he is going from Arica to La Paz:
May 21, 1830, I reached the point where the ravine of Palca joins
another dry ravine. . . . There I left vegetation and humidity. . . .
Soon I began to mount the side of Cachun, and on its summit I
felt at the same time as the first effects of the rarefaction of the air a
very keen cold, due to the elevation. (Vol. II, p. 377.) . . .
The slope became still steeper. ... I felt more and more the severe
effects of the rarefaction of the air, a very violent headache and a great
difficulty in breathing; my arrieros, their mules, and even my dog, my
faithful Cachirulo, were forced to stop every twenty or thirty meters,
tormented like me by the soroche. . . .
Whenever one feels the illness due to the rarefaction of the air,
the natives say that he has the soroche. They fail to recognize the real
cause, the great elevation above sea level, and attribute it to mineral
emanations from antimony, called in Spanish soroche. It is this suf-
fering, this difficulty in breathing in the very lofty parts of the Cordil-
leras that has given them the name of puna brava. Some travellers use
for the Peruvian Cordilleras the word Paramo,, not used in the coun-
try, and which does not take the place of the word Puna, meaning a
lofty plateau, dry and deprived of trees.
After many fatigues, we reached the top of the last slope; I was
at last on the crest of the Cordillera. (P. 378.) . . . Ever since my
arrival at the summit of the Cordillera, I had been suffering terribly
irom the rarefaction of the air. I felt frightful pains in my temples;
I had nausea like that produced by seasickness, I breathed with dif-
ficulty. At the least movement, I felt violent palpitations and general
discomfort, added to an exhaustion which all my efforts failed to over-
come. I had very strong proof of what habit can do. While I was suf-
fering thus, I saw two natives, sent as couriers, nimbly and easily
climbing on foot places incomparably higher than those in which I was
in order to shorten their journey. . . . Yet they were at an elevation
equal to that of Mont Blanc. In the evening I had a severe hemor-
rhage from the nose which relieved me a little; yet I passed a night
which was all the more terrible because I was without shelter, ex-
posed to a keen and cutting cold which froze all the water in the
neighborhood. (P. 380.) . . .
May 23. I still felt the effects of the rarefaction of the air; head-
ache and palpitation of the heart did not leave me a moment of repose.
. . . My muleteers told me that a few months before a Spaniard who
was taking the same route as they was so much affected by the rare-
faction of the air that the very first day he experienced very alarming
symptoms, and being unable to continue, he died the following night,
without being able to get the least relief. They mentioned many other
instances in which the travellers whom they accompanied had suffered
atrociously from what they call the soroche. (P. 387.) . . .
May 24. As I descended I breathed more easily, and I hoped that
before the day ended at least a part of the discomfort I felt from the
rarefaction of the air would cease. (P. 390.)
38 Historical
May 29, d'Orbigny arrived at La Paz (3720 meters) :
As I had felt much better when I had descended from the western
plateau to the Bolivian plateau, I expected to feel no more effects from
the rarefaction of the air; but in the city of La Paz it was far different.
At night I felt as if I were suffocating in my room. I could not climb
the steeply sloping streets without being stopped every ten paces by
palpitations and lack of breath. If I talked with animation, suddenly
speech failed me; when invited to several houses to take part in a
general entertainment, I could not waltz twice around without stop-
ping, suffocated by the same symptoms; and I almost died one day
when I tried to walk to Los Obragos, a village one league away, to
reach which I had to climb a very steep slope.
This discomfort lasted during the whole of my first stay in La Paz.
Persons born in the country feel no effects at all. All assured me that
one finally gets acclimated, and I myself had the proof of this on my
return three years later. However, I should advise persons with weak
lungs not to subject themselves to this test, which gave me the most
pain in all my travels. (P. 404.)
However the acclimatization of which d'Orbigny boasts was not
as complete as one might think. It is true that in the account of
his second stay in 1832 at Potosi, Oruro, and La Paz he does not
mention any symptoms (Vol. Ill, p. 283 et seq.) ; but he returns to
the subject when he tells of certain ascents:
I had to stop (July 5, 1832), while I was going from Cochabamba
to the country of the Moxos, beside a frozen lake nearly 5000 meters
above sea level. We felt the excessive cold all the more because we had
no shelter, and the air was so rarefied that I could hardly breathe.
(Vol. Ill, p. 176.) . . . The next day, on the way down, . . . with the
region of the clouds, vegetation began; up to that time I had felt an
oppression in my chest, so I cannot express the pleasure I felt when I
began to breathe more freely a less rarefied air (P. 117.)
A German traveller, Ed. Poeppig, discusses the subject at greater
length; he was staying at Cerro de Pasco (4350 meters) :
The new-comer to Cerro de Pasco is subject to serious inconven-
iences; walking, even on level ground, tires him extraordinarily; in
streets sloping upward, respiration becomes short and painful, he is
seized by headaches, by afflux of blood to the lungs, certain signs that
he will not be able to escape the attacks of the puna any more than
other foreigners. In vain does he try to brace himself energetically
against the sickness; it conquers him and triumphs over the strongest
wills. Just as during a violent attack of seasickness, the spirits are de-
pressed, the senses blunted, disgust and hypochondrial discourage-
ment transform the most robust, the most animated, the most coura-
geous in a surprising manner. The physical sufferings, when the attacks
of this sickness begin, are more painful and more varied than in the
usual forms of seasickness. When the puna (also called Veta, Sorocho,
Mountain Journeys 39
or Mareo) is felt only moderately, the patient complains of a difficulty
in breathing, which compels him to stop after about ten steps, and he
tries in vain by deeper inhalations and a greater expansion of the chest
to draw more of the life-giving element into his lungs. He feels as if
he were shut up in a room without air, and the distressing sensation is
increased by the failure of all his attempts to conquer his loss of
strength'. The feet can hardly support the body, the knees bend, and
every opportunity to rest, no matter how frequent, even after only a
few steps, is welcome. It is a torment to climb streets sloping up-
ward, and while he heaves himself painfully towards home, it is a
real joy to find a doorway, a corner where he can stop and lean against
something, burdened as he feels. The distress lessens only during
absolute repose; but the conviction of the absolute necessity of the ill-
ness, the incapacity for any intellectual effort, and the sense of loss of
precious time bring on ill humor and discouragement, so that a vigorous
man acts like a little child.
Those who are most seriously affected by this illness are often
seized with syncopes, symptoms of an afflux of blood to the head and
the lungs, with an indefinable distress; and without fever, even with a
feeling of inner chill, with hands and feet numb, their pulse beats at
the rate of 108 to 120 times per minute. The unconquerable fatigue,
the tendency to sleep are far from bringing on refreshing drowsiness,
so that they cannot find repose. In fact, night brings the strongest
feelings of suffocation, it is a real martyrdom; unable to endure a pros-
trate position any longer, the unhappy patient seeks comfort beside
the scanty fire which hardly keeps alive in the fireplace, at the risk of
breathing air laden with coal fumes. The eyes are so weak that one
can hardly read; in some, moreover, slight headaches appear, whereas
in others there predominate discomforts and disorders of the digestive
organs which resemble seasickness, from which, however, the puna
is distinguished by its course as well as by its causes.
When this painful stage is nearly over, often very distressing
critical symptoms appear. After 6 or 7 days, the violent symptoms
usually ameliorate in those who have strong lungs and a good consti-
tution; otherwise, weeks may pass before the patient improves. An
eruption of urticaria appears over his whole body, or is limited to the
lips, on which it causes scabs, bleeding, or unendurable pain. ... In
persons with thin skin and fair complexion, blood may issue from the
skin without any wound, so that while the puna lasts, many dare not
shave. In spite of the severity of the symptoms, there are hardly any
cases in which they have caused death, and there is no danger except
for those with weak lungs and especially those with heart disorders.
(Vol. II, p. 84.)
Poeppig then explains the reactions of different temperaments
and different races, and gives therapeutic advice; he admits a cer-
tain degree of acclimatization for Europeans.
He next states that the residents of the country, even those born
there, are not absolutely immune to the illness, especially when the
nights are cold. The Indians have a sort of immunity. Beasts of
40 Historical
burden have symptoms like those of men; dogs feel no effects; cats
are scarce in Cerro and in lofty places, and their young are hard
to raise; hens do not lay there and seldom brood.
The account 35 given by M. Boussingault of the ascent of Chim-
borazo, made December 16, 1831, is in strange contrast with what
we have just reported. We have seen that d'Orbigny was seriously
attacked by mountain sickness at about the height of 3700 meters;
Poeppig has described to us the sufferings of Europeans who have
come to Cerro de Pasco (4350 meters) ; now M. Boussingault and
Colonel Hall, his companion, climb nearly to the summit of Chim-
borazo (to 6004 meters) and report almost no serious discomfort.
M. Boussingault left Rio Bamba, where he had been staying for
some time, December 14, 1838. He was accompanied by Colonel
Hall, with whom he had already made ascents of Antisana and
Cotopaxi. December 14, they slept at the farm of Chimborazo
(3800 meters), which they left on December 15 at seven o'clock in
the morning, guided by an Indian from the farm. When they had
reached the height of Mont Blanc, the breathing of the mules was
hasty and panting:
It was noon. We were walking slowly, and as we were advancing
upon the snow, the difficulty of breathing while we were walking be-
came more and more noticeable; we easily regained strength by stop-
ping every eight or ten steps, without sitting down. At equal heights,
I think I have observed that it is more difficult to breathe on the snow
than on rocks; I shall attempt later to give an explanation of this.
(P. 155.)
This first attempt failed; the snow, which had become too deep,
checked the progress of the travellers, who sank in it up to their
waists; they went back down to the farm.
The next day, they started at seven o'clock by another route,
the one followed by Humboldt, and ascended on muleback to 4945
meters. There they had to dismount, since the mules could no
longer carry their weight; it was a quarter of eleven. The two
travellers continued to ascend on foot.
We stopped to breathe every six or eight steps, but without sitting
down. . . . But as soon as we reached a snowy surface, the heat of the
sun became suffocating, our respiration was painful, and consequently
our pauses for rest became more frequent, more necessary.
We kept absolute silence during our advance, since experience had
taught me that nothing was as exhausting as conversation at this
height; and during our halts, if we exchanged a few words, it was
almost in a whisper. It is largely to this precaution that I attribute
Mountain Journeys 41
the health which I have consistently enjoyed during my ascents of
volcanoes. This wholesome precaution I imposed despotically, so to
speak, upon those who accompanied me, and on Antisana an Indian
who broke the rule by calling at the top of his lungs to Colonel Hall,
who had strayed from us while we were passing through a cloud, was
attacked by vertigo and had a slight hemorrhage. (P. 159.)
They finally reached the foot of a peak of trachyte which barred
their way; it was a quarter of one, the height reached was 5680
meters, the thermometer stood at 4 degrees, and the air was very
full of moisture, a condition which is constant on the glaciers of
the Andes, according to M. Boussingault. Finally, after a rather
long rest, after studying the terrain carefully, they once more
began their climb:
We were already beginning to feel more than we ever had the
effect of the rarefaction of the air; we were compelled to stop every
two or three steps, and often even to lie down for a few seconds. When
once seated, we recovered immediately; our sufferings occurred only
while we were moving. (P. 250.)
Finally they arrived at a height of 6004 meters, an elevation
which no one had yet reached; however this was not quite the
summit of Chimborazo:
After a few moments of rest, we were entirely recovered from our
fatigue; none of us felt the symptoms experienced by most of those
who have ascended lofty mountains. Three-quarters of an hour after
our arrival, my pulse rate, and that of Colonel Hall too, was 106 per
minute; we were thirsty, we were evidently in a slightly feverish con-
dition, but it was not at all painful. (P. 251.)
The rarefaction of the air generally produces very marked effects
in persons who climb high mountains. ... As for us, we had, it is
true, experienced difficulty in breathing and extreme fatigue while
walking, but the symptoms ceased with the motion; when we were
resting, we thought we were in a normal condition. Perhaps the mild-
ness of the symptoms produced in us by the rarefaction of the air
should be attributed to our prolonged stay in the lofty towns of the
Andes.
When one has seen the bustling in cities like Bogota, Micuipampa,
Potosi, and still others, at an altitude of 2600 and 4000 meters; when at
Quito, at an elevation of 3000 meters, one has witnessed the strength
and prodigious activity of the toreadors; when one has seen young and
delicate women dancing all night long in localities almost as high as
Mont Blanc, where the famous de Saussure could hardly find enough
strength to consult his instruments, and where his vigorous moun-
taineers fell fainting while digging a hole in the snow; finally, when
one remembers that a celebrated battle, that of Pichincha, took place
at a height nearly that of Monte Rosa, one must admit that man can
42 Historical
become accustomed to breathing the rarefied air of the highest moun-
tains. (P. 245.)
But a German traveller, Dr. Meyers,"1 who in his journey around
the world from 1830 to 1832 stayed for some time in Peru and in
April, 1831, made the ascent of the volcano of Arequipa (5640
meters), speaks of mountain sickness in terms which recall the
description of Poeppig:
At two o'clock in the afternoon we reached the summit of the
mountain; my strength was exhausted, and we were suffering from the
painful illness called sorocho. Little by little the symptoms of a nerv-
ous or feverish state from which we had been suffering during the
whole ascent had increased. Respiration took place with increasing
difficulty, and gradually vertigo appeared, nausea, vomiting, then nose-
bleed and fainting; in this condition we were forced to lie down on the
ground, but rest restored our strength and permitted us to walk on
again.
The illness from which we were suffering deserves to be studied
here; all travellers have heard of it, as soon as they have set foot on
the coast of this country, expressing the intention of travelling in the
mountains. In Peru they call it sorocho, and in Quito mareo de Puna
or Puna. It appears under different forms. One of its symptoms, which
is found both in the lower regions and on the summit of the Cordilleras,
is a sensation of difficulty in breathing at the least effort. If one is on
horseback, he feels no effect of the sort; but there appears at different
degrees of intensity a sort of half-feverish condition, which is evidenced
by burning heat over the whole body, headaches, dryness of the tongue,
a burning thirst, and loss of appetite. The pulse rate rises to 100 or 110
at the slightest movement. The face reddens, the skin cracks in differ-
ent places so that blood issues; at the same time a general fatigue
appears. That is the usual condition, the first test of those who make
ascents, whether in Quito, Peru, Chile, the mountains of Asia or even
the highest of those in our Europe. . . .
This feverish condition is made worse by exertion and also by the
influence of the violent, dry and cold winds which are so common in
the Cordillera; the well-informed residents of this country attribute
this illness to these winds. . . . The burning effect of the sun in lofty
places also helps to aggravate these symptoms ... it is a factor in the
headaches and the half-feverish condition. There are some persons
who attribute the illness to exhalations from the metallic veins and
deposits of sulphur so common on the summit of the Cordilleras.
The sorocho has been compared to seasickness, and it has even been
said that those who are not subject to the latter are spared by the
former. That seems to us a mistake. The half-feverish condition which
we described previously is the basis of this illness, and when it becomes
worse, it brings on the characteristic symptoms of diseases of the brain,
the respiratory organs, and the digestive organs. One of these three
organs is always particularly affected, so that different forms of the
illness result. When the chest is particularly affected, difficulty in
Mountain Journeys 43
breathing is added to the general fever; a sensation of weight in the
chest appears, and the respiratory rate, like the pulse rate, increases;
then come lacerations of the lungs, symptoms of choking, and even
hemorrhages, a very rare phenomenon. . . .
The death which has been observed in beasts of burden came, in
our opinion, from suffocation; we ourselves, in ascending the volcano
of Arequipa, experienced such respiratory difficulties that we had to
stop every ten steps. Loaded animals, which are not allowed to do so,
go on until they drop. In other cases, the illness attacks the digestive
organs in particular, and then there appear nausea, qualms, extreme
weakness, and finally vomiting, which gives a little relief. Affections
of the brain are much more dangerous; they are also characterized by
nausea and syncope, by a peculiar condition resembling drunkenness,
and even by madness.
In general it is admitted that at great heights the pulse rate is more
rapid; that is because respiration itself has become much more rapid in
a rarefied air. But neither respiration nor circulation is accelerated if
one keeps perfectly quiet; several times, on the plateau of Tacora, after
sleeping our pulse rate was no more than 70 or 72 per minute, whereas
a few hours later the mere act of riding made it rise to 100 and 110.
(P. 34 et seq.)
They reached the summit of the mountain in a state of absolute
exhaustion, and descended in a feverish condition which had not
completely disappeared the next day. (P. 38.)
The account of the illustrious naturalist Charles Darwin iT agrees
perfectly with what we reported above in regard to the Chilean
Cordillera. On May 20, 1835, he crossed the Andes, going from
Santiago to Mendoza through the pass of Portillo (4360 meters) :
About noon we began the tiresome ascent of Peuquenes, and then
for the first time we felt some slight difficulty in breathing. The mules
stopped every fifty steps, and the poor brave animals, after a few
seconds, started again of one accord. Shortness of breath in rarefied
air is called by the Chileans puna; and they have very ridiculous ideas
about its cause. Some say: all the waters here have the puna; others:
where there is snow, there is the puna; which no doubt is true. It is
considered a sort of disease, and they showed me crosses on the graves
of people who had died "punado." Except in regard to people who had
lung or heart diseases, I think that these ideas are mistaken. No doubt
at these elevations a very sick man will experience greater difficulty
in breathing than others, and if he dies, this may have been the cause.
The only sensation I felt was a slight oppression in the head and
chest; this sensation is similar to what one feels when he leaves a warm
room and exposes himself to icy air. There was much imagination in
this; for, having found fossil shells on the highest peak, I forgot the
puna completely in my joy. But certainly fatigue from walking is ex-
treme, and breathing becomes deep and laborious. I cannot understand
how Humboldt and others could have ascended to an elevation of 19,000
feet; beyond doubt a residence of some months in the lofty region of
44 Historical
Quito had fortified their constitutions against such fatigue. However
I was told that at Potosi (about 13,000 feet) foreigners do not become
accustomed to the atmosphere until they have dwelt there a whole year.
The natives all recommend onions for the puna ... as for me, I found
nothing equal to fossil shells! (Vol. Ill, p. 393.)
The English officers Smyth and Lowe,38 who undertook a jour-
ney in 1834 to find a navigable passage to the Atlantic by way of
the Pachitea, the Ucayali, and the Amazon, crossed the Cordillera
much nearer the equator. They left Lima September 20, 1834.
September 25, a little beyond Pucachaca, the illness attacked them:
The air became very cold ... we began to feel what is commonly
called the veta or marea (seasickness), which consists of an acute pain
through the temples and the lower and back part of the head, and
which completely prostrates those attacked by it. ... (P. 25.)
They reached Cerro de Pasco September 28:
Because of the altitude, and especially while we were ascending,
we felt a difficulty in breathing which oppresses the lungs, especially
in new-comers; but after some time, the lungs become accustomed to
the condition of the atmosphere, and this illness disappears. (P. 42.)
Moreover, these facts were so well known in the mountainous
regions of South America, that in 1842 a Scotch physician, Archi-
bald Smith,3'1 summarized in the following words the notes he had
collected during a journey to Peru:
Veta, Soroche, la Puna, Mareo de la Cordillera. A headache with
throbbing and a painful sensation of fullness in the temples, combined
with a great oppression and tension of the lungs, and frequently with
stomach disorders, are the symptoms usually felt during the first days
when crossing the Cordilleras or staying in Cerro de Pasco. If one
walks quickly, especially if one climbs a hill, he feels extreme fullness
in the chest, the temporal arteries throb violently, and headaches come
on. If one tries to run, these symptoms appear immediately, and he
is glad to stop and regain breath. Breathing a frosty air, July 3 at
midnight, in a miserable hut in the pass of Tucto (4855 meters), gave
me an excruciating sensation along the tracheal artery; until I began
the descent, I constantly felt afraid that some blood vessel had opened
in my lungs . . . On another occasion, on another route . . . my breath-
ing was panting and difficult.
Many young persons become accustomed to the effects of the rare-
fied air, so that they have headaches and dyspnea only during strenu-
ous exercise. Some persons, on the contrary, and especially the ple-
thoric, cannot cross the Cordillera or live in Cerro de Pasco without
headaches and respiratory difficulties; when they cross the Cordillera,
traveling over these lofty and icy plains which the natives call Puna,
they are very likely to suffer from epistaxis. (Vol. LVII, p. 356; 1842.)
Mountain Journeys 45
The evidence of the French botanist Claude Gay 40 is no less con-
clusive. Now the authority of this scientist is great, since for nearly
fifteen years, from 1828 to 1842, he explored the Cordillera of the
Andes. He expresses himself thus:
I left Lima (1841). . . . After a march of four days, we crossed the
first Cordillera by the pass of Tingo, 4815 meters above the level of the
sea. There we felt a strange discomfort, the result of the great rare-
faction of the air, known in America by the name of soroche, pouno,
etc. It can very well be compared to real seasickness; there are the
same symptoms, the same distress, headaches, vomiting, and such pros-
tration that it almost makes life a burden, and kept me from going to
consult my barometers and thermometers, which were only two paces
from me. . . .
This illness lasted some time; but subsequently I finally became
accustomed to this rarity of the air, and I could take magnetic readings
at an elevation of 4685 meters and carry out several other tasks of ter-
restrial physics without being noticeably inconvenienced. (P. 28.) . . .
The Indians of Cuzco . . ., although constantly at an elevation of
10,000 to 14,000 feet, are not at all inconvenienced by the great rarity
of the air; they walk and talk with as much ease as we do in the low
plains: and so there are found in these regions the loftiest towns and
cities in the world; Ocoruco at 4232 meters, Condoroma at 4343. There
are some post-houses, for example, that of Rumihuani, which are at
an elevation of 4685 meters, and shepherds' houses at 4778 meters, that
is, almost the height of Mont Blanc. (P. 33.)
The celebrated German traveller J. J. von Tschudi41 gives an
almost complete monograph on this subject.
At the great altitudes to which the Cordillera rises, the effect of
the rarefied air upon the organism is seriously felt; it is evidenced
especially by a condition of extraordinary fatigue and great difficulty
in breathing. The natives call this effect Puna or Soroche, the Spanish
Creoles call it Mareo or Veta, and attribute it to metallic emanations,
especially those of antimony, which plays a very important part in
their physics and metallurgy.
The first symptoms of the Veta usually appear at a height of 12,600
feet, and consist of vertigo, buzzing in the ears, and disturbances of
vision, accompanied by violent headaches and nausea. These symptoms
attack horsemen, but not so much as those on foot, it is true. The
higher one ascends, the more these symptoms increase, and to them is
added exhaustion of the legs so great that one can hardly move, with
very painful respiration and violent palpitations. Complete rest checks
these symptoms for an instant, but at the slightest movement they
instantly reappear, and are often accompanied then by fainting fits
and vomiting. The capillary vessels of the conjunctiva, the lips, and
the nose burst, and blood issues in drops. The respiratory and diges-
tive mucous membranes are the seat of similar symptoms; diarrhea
and the spitting of blood are the evidence of the Veta in its worst form.
46 Historical
One can compare this disease approximately to seasickness (whence
its name of Mareo) ; but it alone produces respiratory distress. It is
not unusual to see these symptoms become so serious that they cause
the death of travellers. In 1839 at Pachachaca I met an officer who
was carrying dispatches from Lima to Cuzco, but who, one year, while
crossing at the Piedra parada, died in consequence of pulmonary and
intestinal hemorrhages caused by the Veta. All residents on the sea-
coast and the Europeans who are crossing the high Cordilleras for the
first time feel this illness which is usually not persistent in healthy
persons, but which attacks severely those who are weak, nervous, with
diseases of the lungs or heart, and also the plethoric and the obese. A
German trader from Lima, a very corpulent man, who had gone to
Cerro de Pasco on business, at the end of a few hours had to leave the
city rapidly, and descend into the valley to escape the Puna.
By a long stay in these lofty regions, the organism becomes ac-
customed to this effect of rarefied air. Vigorous Europeans can even
climb the highest mountains nimbly and move about there as freely
as on the coast. I had the Veta only twice, but very severely; once on
a lofty plateau, and once on the mountain of Antaichahua. The first
time I crossed the Cordillera, I did not feel the least inconvenience,
and I was able, getting off my tired horse, to walk a long way without
feeling symptoms of the Veta, so that I thought I was completely im-
mune to it. . . .
The Indians of the mountains, who have been living since child-
hood in this rarefied air, are not subject to the Veta. . . . The physicians
of Lima are accustomed to send to the mountains persons who suffer
from prostration, so that the pure air may give them back their
strength; but there they are attacked by the Veta most severely, and
often lose their lives in the Cordillera ....
The Puna seems to have a worse effect upon certain domestic
animals than upon man himself. This is particularly true of cats; these
animals cannot live above an altitude of 13,000 feet. They have often
been brought to lofty villages, but always in vain, for after a few days
they were seized by terrible convulsions like those of epilepsy to which
they succumb. . . . These sick cats do not try to bite, or to run away. . . .
In this country they are called azorochados and are given antimony.
The delicate breeds of dogs are also affected, but not so seriously.
Travellers in the Cordilleras are also subject to symptoms known
by the name of Surumpe. . . . These are eye affections due to the effect
of the reflection of the sun on the snow. (Vol. II, p. 66 et seq.)
In his ascent of the Cordillera, Tschudi for the first time saw
horses attacked by the veta, at the elevation of about 4000 meters:
First they walk more slowly, stop frequently, tremble all over, and
are prostrated. The higher they ascend, the harder they tremble, and
the oftener they fall. If they are not unsaddled, if they are not allowed
to rest completely, they lie down on the ground. The arrieros bleed an
animal in this condition in four places: at the end of the tail, on the
palate, on the two ears; they often cut their ears and tail half -off
and split their nostrils to the width of several inches. This last method
Mountain Journeys 47
seems to me to be rather useful, because the animals can then breathe
a larger quantity of air. As a preventive garlic is placed in their
nostrils. Mules and donkeys suffer less from the Veta, probably be-
cause they know better how to rest. Horses born on the Sierra are
almost immune to these symptoms. (Vol. II, p. 32.)
A very striking episode in the account of Tschudi is the story
of his twenty-four hour stay in the icy Puna of Peru, at an average
elevation of 4300 meters:
I was beginning to climb the mountain vigorously when I felt the
dangerous effect of the rarefied air; while I was walking I experienced
an unknown distress. In order to breathe I had to remain quiet; even
then I could hardly succeed; if I tried to walk, an indescribable anguish
seized me. I heard my heart beating against my ribs; my breathing was
short and interrupted; there was an enormous weight upon my chest.
My lips were blue, swollen, cracked; the capillaries of the conjunctiva
burst and a few drops of blood issued. My senses were strangely
blunted; sight, hearing, touch, were altered; before my eyes there
floated a thick cloud, grayish, often reddish, and I shed bloody tears.
I felt as if I were between life and death; my head whirled, my senses
failed, and I stretched out trembling on the ground. In truth, if the
most precious riches, if immortal glory had awaited me some hundreds
of steps higher, it would have been physically and mentally impossible
for me merely to stretch out my hand towards them.
For some time I x'emained lying on the ground in this half-fainting
condition, then I recovered a little, hoisted myself painfully on my
mule, and I succeeded in going on. (Vol. II, p. 152.)
The accounts given by de Castelnau 42 are no less explicit, and
contain many interesting details:
Our stay in September, 1845, at Chuquisaca, a city of some 11,000
to 12,000 souls (Bolivian Republic), was rather gloomy. . . . Most of my
companions were also affected by the soroche, an illness caused by the
rarefaction of the air at high altitudes (according to the observations of
M. Pentland, Chuquisaca is 9343 English feet (2847 meters) above sea
level) : it is especially while climbing the uneven streets that one feels
this painful sensation of suffocation; dogs, horses, and beasts of burden
are equally subject to it there, and I have seen some beasts of burden
from whose nostrils blood was dripping. In this case, muleteers usually
make them swallow cloves of garlic. Animals have often died from such
symptoms; this is especially true of horses. No matter how little they
are urged on, they try to overcome the distress they feel, and some-
times fall dead in the streets; mules, on the contrary, stop of them-
selves and start only when they are rested, in spite of the ill treat-
ment to which an unwise master may subject them. (Vol. Ill, p. 317.)
At La Paz (3717 meters) , de Castelnau attended a bull fight:
Unfortunately (he says) the bulls of La Paz, raised on the frozen
plains of the Puna, and which besides probably had the soroche, which,
48 Historical
by the way, is terrible in this city; these bulls, I say, showed energy
only in fleeing before base toreadors on foot who tried to hold them
back by pulling their tails. The angry people rushed into the arena,
'and by dint of tormenting these unhappy animals, finally obtained the
desired result, that is, the death of two or three Indians. (P. 376.)
One of the travelling companions of Castelnau, Weddell, climbed
the volcano of Arequipa in October, 1847. He expresses thus the
sufferings which he felt on this ascent:
The difficulty in breathing which our animals experienced com-
pelled us to renounce their assistance. ... In advancing we had to
tack, and even so we could not advance ten steps without stopping,
so as to let the oppression which had seized upon our lungs pass. As
we mounted higher, not only did this oppression increase, forcing us to
make longer pauses, but weariness of the limbs was also added: a
symptom more distressing than the soroche, because a halt was not
enough to check it ... .
The last strength of my companion was exhausted and he had to
leave me. Alone I continued my journey, panting; ... I could hardly
advance more than two or three meters without stopping to get my
breath. (P. 449.)
In May, 1846, de Castelnau left Lima for Cuzco. He therefore
had to cross high mountains. At the pass of Vinda (4720 meters) ,
the soroche attacked him very severely:
Vegetation, even the stunted thistles, disappeared. M. d'Osery
complained bitterly of the soroche, and he was forced to pause con-
stantly, as was Florentino. Here this disease is called veta, and people
believe that it is due to the presence of veins of antimony. . . .
Hardly had we reached the little settlement of Casacancha when
as I dismounted I was attacked by the soroche, the effects of which I
had not felt until then; I vomited bile abundantly, and felt all of the
symptoms of seasickness to which I am very subject.
When in the morning, after a very bad night, I wished to mount,
I felt the absolute impossibility of it. M. d'Osery could hardly drag
himself along; Florentino, a former sailor, was stretched out on the
ground; little Catana alone was playing as usual, and seemed to feel
no effects of the soroche. At last, understanding how indispensable it
was to reach less inhospitable regions, we succeeded in mounting in the
afternoon; but after going less than one league, we literally fell at the
door of a farmhouse, where we were well treated. (Vol. IV, p. 194) . . .
The altitude of Cerro de Pasco is estimated at 13,673 English feet
(4166 meters) . . In spite of the burning rays of the sun, one is chilled
as soon as he is in the shade, and he is constantly under the painful
effect of the soroche. . . . The climate is so fatal that priests try to
keep their pastorate for only three or four years, in spite of its enor-
mous benefices. . . . The population, in 1845, was 18,000 souls ... It is
only to the silver mines that this population is due. . . . Barley will not
go to seed there. (P. 196.)
Mountain Journeys 49
De Castelnau, after a few days, made an excursion to a nearby-
cavern, situated at a height of 4400 meters, in which he found the
bones of prehistoric animals, among others a sort of armadillo
(probably a glyptodon) :
We were suffering frightfully (he says) from the soroche, the
stifling from which forced us to rest constantly; even the -Indians
seemed affected by it.
A French tourist with a picturesque account, M. de Saint-Cricq,
who published his travels under the pseudonym of Paul Marcoy,4*
felt similar symptoms while he was going from Arequipa to Puno.
He had passed the night at the post-house of Apo (no date) :
After an hour's walking, which had raised us some hundreds of
meters, I began to feel a general discomfort which I attributed to the
insufficiency of the atmospheric pressure. This phenomenon, which
the mountain Quechuas call soroche, and to which they are immune,
gifted as they are by nature with lungs a third more capacious than
those of Europeans, is attributed by them to poisonous gases produced
by antimony, (in Quechua soroche), even in places where this metal
does not exist. A contraction of the diaphragm, dull pains in the dorsal
region, twinges in the head, nausea and vertigo are forerunners of this
strange disease, which are sometimes followed by syncope. But I did
not go that far. My guide, warned of what I was feeling by my livid
pallor and by my efforts to remain in the saddle, gave me a clove of
garlic, urging me to crunch it. ... I obeyed . . . but the antidote . . .
having produced no effect, my Esculapius advised me to give myself
several blows with my fist on my nose, and since this would cause
a hemorrhage, it should bring prompt relief; but this method seemed to
me much too heroic, and I preferred to nibble a second clove.of garlic. . .
About twenty minutes passed, and whether the remedy began to
work or whether my lungs by degrees became accustomed to this thin
air, I felt my discomfort passing away. (Vol. I, p. 76.)
Lieutenant Gillis,44 of the English Navy, gives similar informa-
tion, collected, it is true, second hand, but summarized in a very
intelligent fashion.
In the first part of his work, devoted to the geographical de-
scription of Chile, the author speaks of the routes from Santiago
to Mendoza, and especially of the Piuquenes route:
Very few travellers reach its summit (13,189 feet above sea level)
without feeling respiratory troubles; and the poor mules suffer almost
as much as their masters. In Chile, this illness is called puna, in Peru,
veta, soroche, or mareo, indifferently by the natives and the Creoles.
The latter, in their ignorance of its real cause, attribute it to exhala-
tions of metallic veins, so common in the Andes. With variations in
different cases, the disease produces extraordinary fatigue, prostra-
tion, vertigo, temporary blindness, and nausea, quite frequently ac-
50 Historical
companied by hemorrhages from the nostrils and the eyes. Not all
persons are subject to this effect, and it is clear that certain constitu-
tions are more sensitive to it. The muleteers recommend garlic and
onions as specifics. (Vol. I, p. 6.)
The Englishman Lloyd4"' who crossed the great Sierra of Illimani,
expresses himself as follows:
Except for the disease called soroche, which is an affection of the
lungs that is painful and often dangerous, caused by the extreme rare-
faction of the air at this great altitude, almost no illness is known,
except colds and dropsy. (P. 260.)
The French botanist Weddell,4'5 whose sufferings when he was
accompanying de Castelnau we have already reported, returned to
Eolivia later. Coming from Arica, he had crossed the chain of the
Cordillera without noteworthy symptoms, and after he had been
in La Paz nearly two months, he had had no trouble; but on June 22,
1851, while he was botanizing, he wished to climb a steep slope
rapidly; he was suddenly attacked:
I can hardly express my sufferings from the soroche (he says), in
this ascent which demanded of me gymnastic efforts which I was far
from expecting. The fact remains that when I had reached the top of
the precipice with my flowers, and was stretched out exhausted and
panting on the ground, I swore, but a little late, that I would not be
caught that way again. During the first few moments following my
climb, I thought only of getting my breath which seemed on the point
of leaving me, and a few minutes afterwards, when I thought of ex-
amining my pulse, its rate was still 160 per minute. I do not think
I have ever felt greater oppression than during this unexpected botan-
izing expedition. From that day I felt a physical discomfort which I
could not account for, and I foresaw that I was going to be ill. (P. 187.)
He was, in fact, and very seriously.
Except on this occasion, Weddell pays very little attention to
the soroche, although in many passages of his account we recog-
nize suggestions of it, sometimes in men, sometimes in domestic
animals. I find nothing to quote but this interesting remark about
the Indian postillions, who always proceed at a run, on the road
from La Paz to Puno:
They never seem out of breath (he says), whereas in this same
country, a European can hardly run ten steps without being obliged
to stop. (P. 547.)
As you will perceive, there is a very great difference between
this statement and those made by travellers on the Himalaya; the
Indian coolies, they tell us, are often sicker than the Europeans
Mountain Journeys 51
themselves. Weddell is not the only one to note this; the Grandi-
dier brothers were also struck by it.47
August 1, 1858, these travellers left Arequipa for Cuzco:
Here one experiences (says E. Grandidier in his account) a dis-
tress unknown to tourists in the old world, that is, the soroche; the
traveller who crosses the Cordillera feels pains all through his body;
he has pain in his kidneys, in his head, his limbs feel as if they were
broken, blood even gushes sometimes from his nose, eyes or ears. This
general distress is due, not to the presence of antimony, as has been
said without reason, but to the rarefaction of the air and the failure of '
breath. The soroche has even caused the death of some more suscep-
tible persons. Mules are also subject to the effects of the soroche, and
I have heard many examples of these animals dying in consequence
of the rarefaction of the air. (P. 56.)
And further on, while going from Paucartambo to Puno, their
attention was directed to the natives on foot:
The Indian follows the horseman on foot, always running without
ever losing breath, however speedy the horse, and however high the
mountains. The swiftness with which the Indian runs long distances
surprises the European all the more because he cannot, like the native,
overcome the oppression caused by the rarefaction of the air and run
at this altitude without falling immediately. (P. 194.)
In December, the two brothers arrived at La Paz:
The road down to La Paz is wide and well kept; but the slope is
so steep that one can only walk his horse down. This descent is about
a league long, and it takes at least an hour to get to the city. A very
much longer time is needed to climb it, because of the difficulty in
breathing which the mules experience while ascending; nevertheless
I was assured that the Indians mount it running and playing the flute:
they are not subject to the soroche, and in this way they are like the
llama, whose breathing apparatus is adapted to the Cordillera on which
it lives. (P. 225.)
The European who has recently arrived in La Paz feels the effects
of a violent soroche; while he is walking through the town, he is
forced to stop often to get his breath, so great is the difficulty of
breathing and the oppression in the chest. The rarefaction of the air
comes from the great elevation of La Paz above sea level; this eleva-
tion is 3730 meters. (P. 227.)
We have similar accounts from the German traveller Bur-
meister,48 who in the first part of March, 1860, was in the Cordillera,
about latitude 28° S., and longitude 72° W. However, he speaks of
these symptoms only by hearsay; moreover, the maximum altitude
to which he ascended was 14,000 feet:
During my journey (he says) I never suffered from what is called
52 Historical
the Puna, that is, the sickness which usually occurs on high moun-
tains and which consists of difficulties in breathing, nausea, prostration,
vertigo, and other symptoms. Only at first, when I entered the gorges
near Estanzuela, I felt a heaviness in my head, as if I were going to
have vertigo; but I had no other symptoms. . . . Probably I have been
protected by the weakness of my constitution; for strong and portly
people are more easily attacked by the Puna than those who are
thin, spare, or weak.
The symptoms of the same disease appear in animals, and particu-
larly in horses, on the lofty paths of the mountains; they are charac-
terized particularly by trembling of the limbs and violent hemorrhages,
which, however, do not become fatal. Many horses, and especially
the best, fall down on the ground on journeys in the mountains. The
natives call this disease the Trembladera; they claim that in the moun-
tains there are places where it is particularly likely to attack passing
animals; they pointed out one in the Aconquija Sierra, the position
of which, however, I could not determine.
The Englishman Markham, 49 who in 1860 made a journey to
Peru for the purpose of studying cinchona trees and finding a
way of introducing them into the Indies, gives information of the
same sort:
On the heights of the Cordillera, men and animals are subject to a
very painful disease, caused by the rarefaction of the air, and which
the Peruvians call sorochi. I had been ill at Arequipa, so that I was
probably predisposed to the attack of the sorochi, which affected me
violently. Before reaching Apo (May, 1860), an excruciating headache,
accompanied by acute suffering and pains in the lower part of the neck,
made me very ill, and these symptoms grew worse during the night
passed in the post house of Apo, so that at three o'clock in the morning,
when we set out again, I was unable to mount my mule without as-
sistance. (P. 89.)
In the official description of the Argentine Confederation, Dr.
Martin de Moussy/" who had dwelt for ten years in the basin of
the Plata, gives a detailed description of the American form of
mountain sickness:
The name of puna is given to this painful sensation, this distress in
breathing which some persons experience when they are at great
heights. This sensation is certainly due to the rarefaction of the air,
for, at 4200 meters, the general altitude of the plateau, the barometric
column falls on the average to 0.46 meters . . . and it is impossible that
such an enormous difference in the atmospheric pressure should not
produce a profound impression upon the animal constitution. Further-
more, this impression varies in different persons; some have difficulty
in breathing, others suffer from cephalagia, a sort of headache, and a
complete loss of appetite. Many feel no ill effects; but when they try
to walk, almost everyone feels unusual fatigue.
Mountain Journeys 53
As to the puna properly so-called, the difficulty in breathing, it is
not peculiar to the great heights of the Cordillera; there are certain
places of no great altitude where it is felt much more than in others.
We ourselves experienced it at the town of Molinos, which is at an
altitude of only 1970 meters, and in a valley surrounded by granitic
mountains about which there is nothing peculiar. We cannot discover
a cause for this peculiarity, which also exists at different points of
the Andes in Bolivia.
Animals also experience this difficulty in breathing in their first
crossings of the Cordilleras; but they become acclimated rather quickly
and their vigor is so great that mules in good condition and reasonably
loaded never weaken on ordinary journeys. (Vol. I, p. 217.)
Mateo Paz Soldan also gives a description of the soroche in his
Geography of Peru: 51
Cerro de Pasco is situated on a slope 4352 meters above sea level.
. . . The climate of this city is very cold, the temperature averages 44°
F. by day and 34° by night, during the months from July to October, a
season during which a great quantity of hail and snow falls. Some-
times the thermometer falls to 30° and 28° in August and September;
water boils at 180°. Storms, hail, and snow make this country un-
inhabitable from the month of October on. Strangers there are sub-
ject to the Soroche, an oppression in the chest, which in this country
is called veta, and which is the result of the rarefaction of the atmos-
phere, in so lofty a region .... Former miners are subject to a great
many diseases and infirmities. ... If this country did not possess mines
of inexhaustible richness, it would be absolutely impossible to live
here. (P. 172.)
About this period there appeared in the form of a thesis main-
tained before the Faculty of Medicine of Paris a remarkable work
by a young doctor, Ch. Guilbert,52 who, attacked by consumption,
went to La Paz and there found the cure or at least a considerable
amelioration of his dangerous disease. I shall quote the whole of
his very concise description of the soroche:
The soroche or the disease of the puna begins in two different
ways: some immediately have difficulty in breathing, and that has
attracted greatest attention of the observers; in others, and in my opin-
ion this is the largest number, nervous symptoms appear first. There
are even some travellers who have no difficulty at all in breathing.
The same difference is found in the duration of these two classes of
symptoms. Whereas the nervous phenomena last only 12 to 48 hours,
difficulty in breathing and circulation sometimes persists for several
months.
The nervous system is therefore often the first affected, and re-
acts upon the digestive and the locomotive systems. One first feels
nausea, accompanied by very significant spitting. ... At the same time
there comes a very violent headache, compared to a ring of iron which
binds the temples tightly. . . . After the nausea, vomiting appears, often
54 Historical
very painful, which increases the pain in the head. One also expe-
riences vertigo, buzzing in the ears, sometimes drowsiness ....
Another phenomenon is muscular fatigue. . . . This difficulty in
muscular contraction is experienced even on horseback, and to such an
extent that persons who are unable to move have to be taken down
from their horses. But after the first few days, this great fatigue dis-
appears completely after a very short rest. In the cities, new-comers
are easily recognized; they stop for a few seconds every 40 or 50 steps.
Respiration and circulation are speeded up in proportion to the
elevation. The dyspnea is extreme, the inspirations very frequent.
The heart-beats are stronger, more numerous; at the least effort
one is attacked by violent palpitations which continue when he is riding
as well as when he is walking. Even at night, one is often awakened
with a start by strong palpitations in the midst of the calmest sleep. . . .
The beating of the arteries is stronger, that of the intra-cranial
arteries very painful, the pulse is vibrating, almost as in aortic insuf-
ficiency. A rather frequent symptom is a nasal, buccal, or pulmonary
hemorrhage; hemorrhages from the gastro-intestinal mucous membrane
are rare. . . . But when one becomes used to the rarefied air, when equi-
librium is established, and when the different systems are in harmony
with the surrounding medium, hemorrhages are no more frequent than
anywhere else ... An important symptom is the tendency to syncope,
and so one must be very careful about bleeding the patient ....
The nervous symptoms are the first to disappear; the headache lasts
hardly 12 to 24 hours; the nausea and vomiting no longer . . . The third or
fourth day, appetite revives a little; as soon as the patient can take a
little nourishment, the heaviness in the head disappears in its turn,
and there remain only the difficulty of respiration and the rapidity of
the heart-beats, palpitations occurring at the least effort, and making
the lack of breath still worse. Later, when equilibrium has been estab-
lished, little by little all these symptoms disappear, generally at the
end of a few weeks, and one becomes perfectly acclimated to these
lofty regions.
So Guilbert thinks that one can become perfectly acclimated to
lofty regions. He recalls the words of M. Boussingault, which we
quoted above, and adds:
Pichincha is 4996 meters high; the Bolivian general Santa Cruz
defeated the Spaniards there in 1822. Two years after, at Ayacucho, a
village situated at about the same height, the Colombian general Sucre
defeated the viceroy La Serna. . . .
At Corocoro (4430 meters) I saw very bloody bull-fights. These
bulls, nimble and wild, might have given pleasure to the travellers
mentioned by Lombard,53 who saw at La Paz bulls which were gentle
and unable to make the least effort without vomiting; these were bulls
which had recently been brought to the mountains and which were
affected by the soroche, which attacks animals as well as men. ... It
is very rare to cross the Cordilleras without witnessing the sickness
of some beast of burden, attacked by the soroche; it is hastily unloaded,
rubbed, and after a moment of rest, allowed to follow at liberty.
Mountain Journeys 55
In the special chapter I shall give the very eclectic mixture of
theoretical explanations which Guilbert accepts.
The Italian professor Pellegrino Strobel, ,4 who crossed the dif-
ferent passes between Santiago and Mendoza, was lucky enough
not to be affected by the soroche; it is true that he seems not to
have mounted very high:
After what M. de Moussy wrote and what my friends had told me,
I expected to experience on Planchon one of the sensations described
under the name of puna. But — I do not know whether I should say
happily or unhappily — neither here at 3000 meters above the Pacific,
nor on Cumbre of Uspallata at about 4000 meters nor in any other part
of the secondary chains of the Andes, was it granted me to feel the
slightest difference in respiration or appetite, still less any headaches
and other pathological symptoms or physiological phenomena; and yet
on account of the weakness of my constitution and the narrowness of
my chest, it seems as if I should have suffered from it more than any-
one else. I must therefore admit that the puna does not depend solely
upon the rarefaction of the air, but also upon other concomitant
causes, which appear to be wholly unknown. (P. 25.)
However two German travellers, Focke and Mossbach, ■"'•"• who
speak from their own experience, declare that often men and
beasts become ill at still lower altitudes:
Starting at an altitude of 10,000 feet, one feels the beginning of
mountain sickness, that is, a stunning headache; it is the Sorocho, which
attacks also beasts of burden. They refuse to go on, and to cure them,
they are bled under the tongue. (P. 391.)
Finally, I have the statement of a high official of the Peruvian
government, an intelligent man, that having gone to Perina-Cota
(4800 meters) near Guayaquiri, he saw his mules become ill at an
altitude of 3000 meters; out of 40 mules, 16 had to be unloaded.
Some of his companions had nosebleed. During a stay of two weeks
at this great height, he experienced regularly, about three o'clock
in the morning, a feeling of suffocation which awakened him; the
least movement then increased it considerably; these symptoms
lessened during the day. The Indians who accompanied him suf-
fered from the same illness. Even today, the generally accepted
explanation is poisoning by metallic emanations; they try to check
its effects by garlic sachets.
I also learned from this gentleman that while the railroad
tunnel from Lima was being bored, at an altitude of about 4800
meters, all the workmen had been affected, even the most robust.
I am sorry not to have been able to get written details of the
phenomena observed during the execution of this extraordinary
56 Historical
work. It is finished now, and already the locomotive conveys the
travellers up to regions which formerly they could not reach with-
out the most strenuous efforts. Strangely enough, nevertheless a
certain number of them became ill. In a letter addressed this very
year to one of my friends, there is this very characteristic passage:
A special train came for us at Callao, took us up Reinar to Lima,
then from there into the Andes, climbing by successive planes to an
altitude of 3450 meters. . . . We thus journeyed 130 kilometers. . . . The
temperature had fallen, the rarefaction of the air was such that many
persons could not accompany us to the end. They felt extreme oppres-
sion and their eyes were bloodshot.
It would be very desirable to have careful observations made
on this railroad and on the Titicaca railroad too; it would be very
easy for the professors of the Faculty of Medicine of Lima to do so.
I shall finish these quotations from the principal general de-
scriptions of mountain sickness in the Cordillera of the Andes by
copying a very interesting letter written by M. Pissis to Dr.
Coignard, who asked him at my request for information which his
great experience in the mountains made very valuable to me. The
learned geographer in this letter describes very vividly the symp-
toms which he felt, but he does not venture upon any explanation:
Paris, March 17, 1874.
Dear Doctor:
Here are the observations which you requested of me upon the
physiological effects of the rarefaction of the air on lofty mountains.
The general effects are headaches, nausea, great difficulty in breathing
and a contraction in the region of the false ribs, as if one were tightly
squeezed by a belt. These symptoms vary greatly, however, according
to the age and the constitution of the patients; when I crossed the pass
of Tacora (bar. 463 mm.) a negress eighteen to twenty years old, very
sturdy, was extremely ill, she had a profuse nasal hemorrhage, whereas
her mistress, a woman of about fifty years, of weak constitution, was
hardly affected; the same difference is observed in animals; the strong-
est horses are the most likely to die. Nasal hemorrhages are frequent
in them also. After one has lived a certain time in lofty regions, these
effects are no longer felt; the residents of Oruro in Bolivia, at 3,796
meters (average barometric pressure 492 mm.) live as if they were on
the seashore; the Indians run leagues without getting tired, and after a
year's residence, I easily climbed fairly high mountains, which would
have been impossible at my arrival.
The highest point where I saw permanent dwellings are the mines
of Villacote in the province of Chayauta; their altitude is 5,042 meters
and the atmospheric pressure 421 mm. The Indians work there as
they do elsewhere, but they get tired more easily when it snows, for it
never rains in these regions; the workmen, even those in the depths of
the mines, are ill, and yet the decrease in pressure when it storms is
Mountain Journeys 57
hardly 4 or 5 millimeters. The alpacas and the vicunas live in herds at
these heights, the condors fly far above, and I have found a few turtle-
doves there. Although accustomed to the pressure of Oruro, when I
went to these mines, I was always ill, with nausea, headache and dif-
ficulty in breathing, and I could not walk eight or ten steps without
having to stop to get my breath. The manager, who has lived there
for two years, could walk a little further, but always had difficulty in
breathing. At a height of 4,000 meters, the rarefaction of the air has
only a passing effect upon the health, the residents of Oruro and
Potosi become very old, and lung diseases are unknown there; the
residents are generally thin, very active, but have little strength, which
perhaps is partly due to their almost exclusively vegetable diet.
In Chile, the highest point I reached was on the side of Aconcagua
at an altitude of 5,832 meters; the summit has an elevation of 6,834
meters. At the point where I stopped, the barometer reading was
382 mm.; I was very sick and it was impossible for me to climb higher;
my eyes were badly bloodshot; all objects, even the snow, seemed red
to me, and even with my glasses of very dark blue glass, I had great
difficulty in reading my barometer. On the way down, at about 5,000
meters, all these symptoms disappeared.
In my numerous stops in the region of the Andes, I often saw
condors wheeling about the sides of the highest mountains, but never
soaring above their summits; but one should not be hasty in drawing
a conclusion from that fact; for the heights they reach are so great that
they appear only as little black dots; if there were any at the height
of the summit of Aconcagua, they would certainly be invisible, even
if one were at an elevation of 5,000 meters, that is, higher than Mont
Blanc. At 4,000 meters one finds in the Andes of Chile guanacos, swans,
ducks, turtledoves, and even humming birds.
A. Pissis.
If travellers who limited themselves to crossing the passes of
the Cordillera or stopping on the lofty inhabited plateaux of Bolivia
and Peru have experienced such symptoms, one may suppose that
those who purposely attempted the ascent of the mountains which
tower above the average level of the chain have experienced even
more. However this is not always true. We have seen that Hum-
boldt and Boussingault suffered much less on Chimborazo than
other travellers at Cerro de Pasco or even La Paz. Other examples
are no less strange.
For instance, on January 14, 1845, Wisse 5G descended into the
crater of Rucu-Pichincha to the depth of "four times the highest
pyramid of Egypt", and climbed back; he does not mention any
physiological symptom.
We shall discuss these differences later. They are so great that
certain travellers go so far as to deny that mountain sickness exists,
because they never experienced it, and there reappear the explana-
58 Historical
tions about poisonous air, which both the Indians of the Andes and
those of the Himalaya have accepted.
The most remarkable account I know, in this respect, is that of
the French traveller Jules Remy,'7 who made the ascent of Pichin-
cha (4860 meters) on October 2, 1856. The weather was magnifi-
cent, it was warm on the summit of the mountain, where numerous
humming birds were buzzing about. Remy felt no distress.
My breathing is free, easy, excellent, and I feel no symptoms of
distress, a fact worth noting, for it confirms my preceding observations,
although contradicting those of other travellers who had stated that
at these altitudes the decrease of the atmospheric column causes serious
symptoms in different organs.
Only on Cerro de Pasco, a mountain in Peru, celebrated for the
silver mines operated there, are the morbid symptoms manifested in the
. animal organism constant and universal, so far as we know. There one
is infallibly attacked by a strange disease, the soroche. . . .
But if it is noted that Cerro de Pasco is only about 10,000 feet above
the ocean, and that after one has walked seven or eight leagues, normal
health is suddenly restored, although one is then at a much greater
altitude, one is compelled to admit that atmospheric pressure is not
the cause of the soroche, which perhaps should be attributed to ema-
nations from the ground.
However, if one reads carefully this very account of J. Remy,
he finds in it indications of the harmful effect of the altitude; but
their slight importance had escaped our traveller.
He displayed the same immunity in the ascent which, on No-
vember 3, 1856, took him to the summit of Chimborazo; 58 naturally
his negative conclusions were greatly reenforced here. The camp
of the night before was made at an altitude of 4700 meters, a little
below perpetual snow:
The climb continued to be so steep that soon, under the weight of
fatigue, we were obliged to stop frequently to get our breath; then
thirst became extreme. . . . But we felt no symptom of discomfort or
of any morbid affection, mentioned by most of the travellers who have
ascended high mountains.
As soon as we had stopped walking for a few seconds, even with-
out sitting down, we went on with new ardor, with a sort of fury
inspired in us by the sight of the summit so near us. It seemed evi-
dent to us, from this new experience which confirmed so many pre-
ceding ones, that at these altitudes the atmospheric column is still
sufficient not to hamper respiration, and that the short breath and
organic symptoms of which complaint is generally made by those who
reach considerable altitudes must be attributed to some other cause.
Having continued their journey in the midst of clouds, the two
travellers thought, after observing the boiling point of water, that
Mountain Journeys 59
they had reached the summit of Chimborazo, which they estimated
to be an altitude of 6543 meters.
But not everyone is so lucky. In a recent journey, Stuebel,59
while warning the reader against certain exaggerations, confesses
that he suffered considerably in the ascent of Cotopaxi.
On February 8, 1873, at seven o'clock in the morning, the trav-
ellers started from an altitude of 3615 meters; at two o'clock, they
were at a height of 4498 meters. Without great difficulties, they
reached the summit of the volcano of Tunguragua (4927 meters),
without being tired and "without suffering headache." (P. 273.)
March 8, ascent of Cotopaxi (5943 meters, temperature 3.5°)
starting from the Saint-Elie farm:
Some of my people had gone on in advance, others had stayed
behind. They were tired, had become a little timid, and complained
of headache. . . . The arena! has a slope of 35°; it wears down the
strength, so that one must summon all his moral energy not to fall
just as one is reaching his goal. ... It took us twenty-eight minutes for
each hundred meters. (P. 282.) . . .
We began to descend. ... I found little by little all my men; one
had remained 50 meters from the edge of the crater, unable to reach
the goal so near at hand; the others 400 meters away, and most of the
muleteers much lower. Like me, all were suffering from a very violent
headache. Only one felt no effects and was not fatigued; he was carry-
ing my barometer, which, however, is pretty heavy. One muleteer did
not get above a height of 5,600 meters. I could testify that the vomiting
is the effect of the air of these great heights, but not of a passing
weakness of the stomach.
But neither in this ascent nor in the preceding ones, did I see
blood issuing from the noses, mouths, and ears of my people. These
are circumstances upon which other travellers like to dwell. Certainly
it must seem strange that M. Reiss and I mentioned no case of the
sort. Now we reached a height of 6,000 meters three times, and 5,000
meters several other times, an altitude to which few travellers have
ascended. We have always taken with us a certain number of men of
different races. . . . The scientific result of these ascents, in which man
reaches the summits only by using all his strength, will always be of
slight importance. (P. 285.)
2. Central and North America.
Central America. The republics of Central America contain no
peaks the elevation of which is comparable to those of the grand
Cordillera. So it was with great surprise that I found in the tales
of an English navigator of the seventeenth century, Wafer,60 a very
definite mention of mountain sickness.
Wafer took part in the expedition of Dampier, and was one of
the troop who tried to cross the Isthmus of Darien, in 1681. He was
60 Historical
severely wounded, and with four other Englishmen fell into the
hands of Indians, who, after various adventures, restored him to
liberty. They then left the vicinity of the southern sea for the
ocean to the north:
We crossed (he says) several very high mountains, but the last
one was the highest of all; it took us four days to ascend it, although
there were some low spots here and there. As soon as we had reached
the summit, I felt that my head was whirling strangely; I told this to
my companions and the Indians, who answered that they were all in
the same condition. Apparently the illness came from the great height
of this mountain and the thinness of the air. . . . Our vertigo left us as
we descended. (P. 174.)
It should be noted that Wafer and his companions, even the In-
dians themselves, his guides, were in a state of fatigue which was
near complete exhaustion. But in spite of this added circum-
stance, the importance of which we shall see later, I cannot account
for the condition in which Wafer must have been when he says that
he veered enough towards the northwest to reach Chiriqui (3430
meters) , or further yet, Pico Blanco (3600 meters) , which is nearer
the sea to the north.
The only explorers who, in modern times, ascended the highest
volcanoes" of Central America, MM. A. Dollfus and deMontserrat,61
never mention in their detailed and interesting accounts the special
illness of great heights; yet they knew it, having experienced it, as
we shall see later, in their journey to Popocatepetl.
The high inhabited plateaux of Mexico have caused similar ob-
servations, and we shall see, in the chapter devoted to the an-
alysis of theoretical explanations given by authors, that it was in
regard to these plateaux that the discussion which was most fruit-
ful for the topic of this book arose. I shall copy here two interest-
ing quotations relating to symptoms observed in animals:
Horses and mules in Mexico (says Burkhardt)62 are subject to a
disease which is little or not at all known in Europe. If while the sun
is hot they are driven to great efforts or to rapid and continuous move-
ment, they are often seized by palpitations and an acceleration of the
pulse and circulation so great that they have strong convulsions over
their whole bodies.
Profuse bleeding is the only remedy against this disease, which
the Mexicans call asoleado. ... So before buying a horse or mule, the
purchaser takes care to make the animal gallop a little, and then to
notice whether palpitations in the withers give evidence of the disease.
Animals often fall, as a result of this affection, if they are compelled to
work uninterruptedly. (Vol. I, p. 63.)
Mountain Journeys 61
I borrow the other quotation from Heusinger," ; who took it from
Elliotson:
M. Lyell says that the Englishmen who own mines on the plateau
of Mexico, at an elevation of 9,000 feet above the sea, took greyhounds
there to hunt hares; but they could not endure hunting in the rarefied
air, they were out of breath before reaching the game. On the contrary,
their young born in this place are not affected by the rarefied air; they
hunt and overtake the game as well as the best greyhounds in England.
(Vol. I, p. 260.)
But I must not forget that my chief interest here is not the
somewhat chronic and vague symptoms which follow the prolonged
residence on rather moderate heights, but those which suddenly
attack travellers who are ascending very lofty mountains.
From this standpoint, among the mountains whose height is
above the limit at which appear physiological symptoms due to the
altitude, Popocatepetl (5420 meters) should be particularly men-
tioned.
Since the time (1519) when the brave Ordaz ascended it at the
command of Hernando Cortez, and as reward for his courage re-
ceived the authorization to bear a volcano on his coat of arms, and
when a second Spanish expedition was sent by the same con-
queror to get sulphur there (1522) ,04 no mountain climber had trod
the summit of the giant of Mexican mountains. The first European
to ascend it is the English lieutenant, W. Glennie, April 20, 1827.
The sensations experienced by M. Glennie (says the secretary of
the Geological Society in the extract he gives of a letter from this
traveller)65 are those already described by travellers to great heights,
that is, prostration, respiratory difficulties and headache, this last symp-
tom appearing first at the elevation of 16,895 feet (5147 meters). It
was found that tobacco and alcoholic liquors produced an extraordi-
narily rapid effect upon the sensorium.
A few years later, April 27, 1834, Baron Gros,66 attached to the
French Legation in Mexico, made the ascent in his turn.
When he had reached the limit of vegetation, he cried:
We began to feel that we are no longer in the sphere where it is
possible to live. Respiration is hampered; a sort of melancholy which
is not without charm seizes us. (P. 50.)
He passed the night at this height. Before lying down, the
travellers mounted a little higher "to accustom our lungs some-
what by degrees to breathing an air so unfitted for them." (P. 51.)
62 Historical
The next morning, Gros and his six companions set out again:
We walked one behind the other, our alpenstocks in our hands. . . .
We proceeded very slowly, and were forced to stop every fifteen paces
to get our breath. The flask of sweetened water was very useful to me;
for being obliged to breathe with my mouth open, my throat became
so dry that it was painful. (P. 53.)
At 9 o'clock, we had reached the Pico del Fraile. . . . Our guides
through superstitious fear refused to go on ... . The oppression which
I felt was less severe than I had feared, and my pulse rate was only 120
per minute. (P. 54.)
The travellers continued their journey alone, finding the in-
struments which they had to carry "terribly heavy." To get a rest,
they ate lunch:
But only a little; it would be unwise at this height to eat a little
too much or to drink any alcoholic liquor, for the nervous system is
excited thereby inconceivably. (P. 55.) . . .
At noon, we had reached the summit of perpendicular rocks; but
our strength began to fail, and every 10 paces we were forced to make
a long pause to breathe and to permit the circulation of the blood to
grow somewhat slower.
We had to shout to be heard at a distance of twenty paces. The
air is so thin at this height, that I tried in vain to whistle, and M. Eger-
ton had great difficulty in drawing a few notes from a cornet which he
had brought with him.
At half past two, M. de Geroult was on the highest point of the
volcano. He leaped with joy. (P. 57.)
We were exhausted. I had a violent headache and a strong pres-
sure on the temples; my pulse rate was 145 per minute, and 108 after
I had rested a little; but I felt hardly more distress than on Pico del
Fraile. All four of us were frightfully pale; our lips were a livid blue,
and our eyes were sunken in their orbits; and so, when we were rest-
ing on the rocks, our arms above our heads, or when we were lying on
the sand, with our eyes closed and our mouths open, and under our
crape masks so that we could breathe more easily, we looked like
corpses .... We saw three crows fly 200 feet above us. (P. 67.) ....
A great many attempts have been made to ascend to the summit
of the volcano; almost all have failed for different reasons. Some
travellers, when they had reached a certain height, vomited blood,
which compelled them to give up their undertaking. However, in 1825
and 1830, some Englishmen reached the crater. M. W. Glennie is the
first, I think, to have seen it. (P. 68.)
The travellers went down again and passed the night in the
same place as the night before:
We were too tired and especially too excited to sleep well. When I
was awake, I could talk of nothing but the crater, and if I succeeded
in getting to sleep, I was climbing up there all over again, the oppres-
sion came on again, and I was awakened with a start. (P. 64.)
Mountain Journeys 63
MM. Truqui and Craveri, in their ascent in September, 1855,
were more fortunate:
I ought to say (remarks one of them)'" that we experienced almost
no difficulty in breathing during the ascent; at least, we thought that if
we did feel any oppression, it should be attributed only to the fatigue
of a long and difficult climb, (P. 316.)
In January, 1857, under the guidance of M. Laverriere, Director
of the School of Agriculture of Mexico, a scientific ascent of Popo-
catapetl was made, and this expedition was part of a series of
researches on the natural history of Mexico undertaken with the
most praiseworthy ardor by the government of General Comonfort.
M. Laverriere in his notes and memoranda collected the data
which were of physiological interest in this ascent which was so
fruitful from the standpoint of physics and geography. I am
quoting in full his communication, for which I thank him sincerely:
Among the tasks which had devolved upon us was the ascent of
Popocatepetl, situated southeast of the city of Mexico. I expected to
begin our operations by this ascent, because the season at that time
seemed to me particularly favorable.
In fact, all who before us had attempted the ascent of Popocatepetl
had failed or had only partially succeeded. Forgetting the latitude and
the peculiarities of the climate of Mexico, they had made their attempts
at times when such explorations are made in Europe, that is, spring or
summer. I thought, on the contrary, that our expedition should be made
in winter, a period when the atmosphere in Mexico is perfectly trans-
parent and suitable for observations, and when, because of a relatively
lower temperature, the snows which cover the upper part of the cone
occupy a greater surface on its slopes, which lessens the distance to be
traversed in the deep and unstable sands which cover them, while fur-
nishing by their hardness a firmer footing for the traveller.
Consequently our little caravan, composed of Dr. Sonntag, astro-
nomical engineer, a major-domo, two students from the School of
Agriculture, and three servants, left Mexico (2278 meters) on Saturday,
January 17, 1857, in very hot weather; on January 18 passed through
Chalco situated on the lake of the same name; on January 19 through
Amecameca (2493 meters), and entered the vast pine forests which
cover the first foothills of the volcano, reaching the ranch of Tlamacas
(3899 meters) on the evening of January 20.
The ranch of Tlamacas, situated at the foot of the north slope of
the volcano, is composed of a few cabins in which the sulphur occa-
sionally brought from the interior of the crater is refined. It occupies a
clearing near the timberline, and near it are found several varieties of
pines, noteworthy for their hardiness, the excellence of their timber,
and the abundance of their resin, and capable of being acclimatized in
Europe.
We passed the night in this spot. At six o'clock in the evening the
64 Historical
thermometer stood at — 0.3° C, and — 2° C. an hour later. In spite of a
good fire and our blankets, our sleep was uneasy and rested us but
little; the Indians, on the contrary, slept like logs, and the next day
they were up early, in good health and spirits, while we were stret-
ching our limbs and looking surly.
Wednesday, January 21, at five o'clock in the morning, everyone
mounted and set out in silence; the Indians followed on foot. The cold
was so penetrating that in spite of our thick garments we vied with
each other in shivering. A quarter of an hour afterwards, we left the
wood and approached the sandy stretch, going straight towards the
steep slope of the volcano. The horses sank up to their hocks, going
on slowly and painfully. Soon we had to stop frequently to let them
breathe, for the air was so stinging and the path so steep that they
could hardly get their breath.
At half past eight we reached La Cruz (4290 meters). The horses
were worn out, covered with sweat, panting. We dismounted and
sent them back to Tlacamas. Numbed by the cold, we rested a little
while on the sand warmed by the sun whose heat began to be scorch-
ing.
At nine o'clock, each one started out, his alpenstock in his hand,
following our Indian guide, Angel, who with his feet wrapped in some
rags, led the way with a step remarkably easy compared with ours.
We followed him with difficulty, in spite of the care we had taken
to lighten our garments and footgear as much as possible. Soon we
reached a strip of ice which precedes the snow. It was crossed without
too many difficulties, thanks to the notches cut with an axe by an In-
dian sent on ahead with orders to blaze a trail up to the summit of
the volcano.
At the line of perpetual snow (4400 meters on the slope at this
season of the year) I began to feel acute fatigue. I was wet with sweat,
my breath was short and hurried, and it seemed to me as if enormous
weights were fastened to my feet. Near me, a Mexican from Amecam-
eca, named Saturnino Perez, who wanted to accompany us, was climb-
ing with a stronger step; but his pale face, his bluish lips, his wild eyes,
the contraction of his mouth, and the dilation of his nostrils showed
plainly enough the effects of the altitude upon his constitution, hardy
and robust though it was. The slope was steep, it is true; but as the
snow was packed, we experienced less difficulty in advancing than if
we had been on sand or ice. Only the air was so thin, so dry, so cold,
that this advantage was more than compensated.
Soon, since our strength failed, we had to halt, a very short halt,
for the cold seized us straightway. Every forty or fifty steps we were
forced to stop for a minute or two. Our lungs seemed to refuse to act;
they hardly had the strength to raise the chest, which collapsed heav-
ily after each inspiration.
At 300 or 400 meters from the summit, there was a moment of hesi-
tation, of prostration. Although so near, our goal seemed still enor-
mously far away. The extremely steep grade, the metallic glare of the
snow, the rarity of the air caused me inexpressible weakness. So I had
to collect all my energy, appeal to all my reasoning power, and think
of my responsibility in particular to find strength to go on.
Mountain Journeys 65
Finally, thanks to a supreme effort, we reached the edge of the
crater (5280 meters; temperature — 2° C.) through an opening to which
I gave the name of Silicco Breach, in honor of the judicious minister
who had sent us. It was half past one in the afternoon, and the part
of our ascent which had been made on foot had required no less than
four hours and a half.
Within the crater, as soon as we had passed its edge, there was an
inner slope towards the south, composed of sand and rock fragments.
We dropped down upon it like inert masses, hardly conscious. My first
sensation was that of inexpressible comfort. But this comfort lasted only
a short time. The sand which at first I had found warm soon seemed
unendurably cold to me. Moreover as the sun was beginning to de-
scend, a cold little thin wind rose. I was soon shivering. To cheer
myself, I wanted to eat, to drink a few gulps of an excellent sherry
wine which our good Indians had brought. But since my throat was
tight, I could not swallow the food, and the sight of it was distasteful.
Instead of the strengthening effect expected, the wine produced a very
different effect; no doubt because of a perversion of taste, I thought
I had swallowed a stiff brandy, a regular fiery draught which literally
burned my entrails. At the same time, and in spite of my weariness,
a strange agitation seized me; it was a feeling of uneasiness, of distress,
which would not allow me to rest. And yet, when I wanted to move,
my strength betrayed me and almost refused me service. However, I
found strength to climb back to the edge of the crater where I eagerly
seized some snow to quench a little the burning thirst which tormented
me.
This agitation nevertheless passed away a little and my strength
returned for a few hours. But in the evening, and especially during
the night which we passed huddled against each other under a shelf of
rock, a feverish condition seized me; my head on fire, piercing cold in
my limbs, a pulse of 120 to 130, unendurable uneasiness, increased even
more by the dull mutterings in the abyss beside us. It was a night I
shall never forget. And therefore the dawn was greeted with joy, and
after making observations according to our instructions, the signal for
return was given; we left the volcano at ten o'clock and three hours
afterwards, we were back at the ranch of Tlacamas, which we had left
thirty hours before.
The Scientific Committee GS which accompanied our unfortunate
Mexican expedition also made this ascent April 23, 1865; the suffer-
ings were quite endurable:
The line of perpetual snow begins at a height of about 4300 meters
above sea level.
Here everyone dismounts, and climbs over the snow, zigzagging a
little. . . . When one has ascended about 100 meters, he begins to feel
great difficulty in breathing, his lungs are oppressed, and every step,
every movement of his body makes him pant; he has to stop every
twenty steps to get his breath, and there are certain constitutions which
cannot endure the discomfort, although it is not very serious.
The reflection of the sun on the snow is blinding; it is wise to pro-
66 Historical
vide oneself with colored glasses and veils so as not to add to fatigue
and breathlessness the vertigo which would no doubt be caused by
this immense winding-sheet of snow which surrounds one.
We could note, moreover, that the physical sufferings attendant
upon such an ascent have been much exaggerated; none of us had
hemorrhages of any sort. . . .
The Indians, used to this ascent, can carry an arroba (11 kilos)
and they ascend very rapidly. . . .
We reached the summit of the volcano (the summit reached by the
travellers is the Espinazo del Diablo (5247 meters), and not the true
summit, the Pico Mayor (5450 meters). . . . The last steps are rather
difficult; the rarefaction of the air, becoming greater and g'reater, adds
still more to the difficulty of the ascent ....
Hardly had we reached the summit than the difficulty in breathing
which afflicted us ceased to be felt, and our lungs were not oppressed
as long as we were resting. However, all of us could observe a certain
excitement, which increased in some of us to the point of a violent
headache; this excitement can be compared almost to a slight state of
intoxication; the blood circulates rapidly, and the pulse rate rises to
nearly one hundred per minute. (P. 194.)
Besides Popocatepetl, in Mexico there is only the peak of Ori-
zaba (5400 meters) the ascent of which can bring on discomforts
and even symptoms. This happened to Von Muller1'"' and his
companions, September 2, 1856.
The travellers passed the night at 3000 Spanish feet from the
summit:
The consequence of a stay in such rarefied air were soon strongly
felt by all of us. Our respiration had become much deeper and more
rapid, a natural result of the diminished quantity of oxygen reaching
our lungs at each inspiration of this thin air. We all had violent head-
aches with feverish tendency. These symptoms could not surprise us,
because we were at an elevation greater than that of Mont Blanc. . . .
Although we were lying close together, with furs and rugs over us, we
were all shivering with cold and fever. The temperature was below
freezing. (P. 278.)
The next day they wished to complete the ascent:
The climb was extremely steep, so that in 25 steps, we mounted no
more than 8 to 10 feet: besides we had to stop after these 25 steps ....
None of us had nosebleed or such symptoms during the ascent;
but we had severe congestion of blood in the head so that the whites
of our eyes were deep red. . . . All had violent headaches, and shook
terribly with fever. (P. 282.)
A large company of American, English, and Mexican travellers,
including artists, engineers, and mere tourists, tried to reach the
summit of this peak in 1866. They did not succeed either. They
were much distressed by symptoms of which one of the company in
Mountain Journeys 67
the New Orleans Picayune gave a very picturesque and very
strangely worded account. Although I am quoting it, I do not hesi-
tate to say that it seems to me greatly exaggerated; I shall add,
along with the editor of the Alpine Journal, that I am not sure that
I have always understood what the author meant,70 in his obscure
and bombastic style:
At first they sang and whistled while they climbed; but these
noisy demonstrations soon ceased. Respiration became difficult. . . .
Up to about 2000 feet from the summit, the members of the company
were strung out at a great distance from each other. At that time,
some became weak and fell. Blood began to issue from their ears and
noses; their faces were so swollen that old friends knew each other only
by their garments. A few continued to climb some thousand feet, lay
down, went to sleep on the snow or the black dust, and awoke panting.
The artists, laden with their instruments, felt greatly the painful effects
of the atmosphere; with one accord they turned around and went back
down to the place where our companions who had no ambition and
poor endowment of lungs had stopped. . . . The engineers and the others
lay down; they were stumbling as they walked, incapable of will or
action, and calling to those who were ahead. Had it not been for the
continual struggle to cling to life, the distress in breathing, and the con-
stant loss of blood, one would have thought he was asleep and dream-
ing in a hollow in the snow or a gorge filled with ashes. We were
then at an elevation of about 16,000 feet. . . . General S. went on to-
wards the summit. In spite of the claims of the natives, it is doubtful
that anyone ever went as far as we did. During the war with Mexico,
20 years ago at the most, an officer tried to reach the summit; but he
fell paralyzed, at the height of 15,000 feet. His comrades went no
further, and at this point planted a standard the staff of which is still
there.
Two-thirds of our company were out of sight; only three, besides
the terrified guides, went on. Blood issued from our ears, nostrils, and
mouths, and the veins stood out on our foreheads like dark lines; our
progress was more and more uncertain, the slope steeper and more
dangerous . . Colonel C. . . completely exhausted, talked incoherently
like an intoxicated man.
A stone which broke the shoulder of General S. . . . compelled
them to retreat, at about 500 feet from the summit.
North America. As we have seen, North America in many
places has peaks lofty enough for travellers to experience on them
the symptoms of mountain sickness. But the hardy explorers of
the banks of the Colorado, the Oregon (Columbia) , and the upper
Missouri, gave little heed to scientific and picturesque ascents. On
the other hand, the engineers and the officers whom the government
of the United States sent repeatedly to the Far West generally
were satisfied with making trigonometric abstracts, and journeyed
68 Historical
only over the passes, the elevation of which rarely reaches 3000
meters.
However, Colonel Fremont, in his account of his expedition to
the Rocky Mountains of Oregon, gives us an interesting observa-
tion.71
August 13, 1842, in latitude 42° N., the travellers made the ascent
of a lofty peak, and were suddenly extremely weary. The barome-
ter stood at 20.522 inches, the altitude was reckoned at about 10,000
feet (3050 meters) ; the temperature was only 50° F.; they stopped
to camp:
I was seized shortly after (says Fremont) by violent headache and
vomiting which lasted almost all night. These symptoms were probably
caused by excessive fatigue, the lack of food, and also, to a certain
degree, by the rarefaction of the air. . . .
The next day two of our men were sick and lay down upon the
rock; at that time I was seized by headache and vomiting, as on the day
before, so that I was unable to go any further; M. Preuss had reached
his limit, too; the thermometer stood at 50°, the barometer at 19.401
inches. (P. 67.)
August 15. . . . The barometer dropped to 18.293 and the thermo-
meter to 44°; we were at an elevation of 13,570 feet (4130 meters); at
this great height we saw a solitary bee flying . . . This is probably the
highest peak of the Rocky Mountains.
Our careful method of advancing slowly had spared my strength;
and with the exception of a slight tendency to headache, I felt no signs
of the discomfort of the day before. (P. 70.)
The mountain discussed here is marked on the maps by the
name of Fremont's Peak (4130 meters) , in the State of Wyoming.
In the following journey, made in 1943-44, the American ex-
pedition crossed the Sierra Nevada in California at a height of 9300
feet, February 20 (ibid. p. 235) ; June 18, 1844, it reached the sources
of the Arkansas, at a height of 11,200 feet (3413 meters) (P. 285) ;
in neither case does the account indicate physiological symptoms.
I found a similar account in the immense scientific publication
of the expedition organized for determining the route of the trans-
continental railroad.
September 12, 1853, Captain Gunnison,72 topographical engineer,
ascended Mount Creek, near Fork Lake in Colorado:
The agreeable and inspiring effect of the pure air of the mountains
at this elevation, a favorite theme for the eloquence of trappers and
scouts, manifested itself in our men by shouts of noisy joy. But the
violent physical exercise soon made them breathless; and while climb-
ing the hills, our animals were soon completely exhausted, if they did
not stop often to get their breath; but a few moments of rest gave them
back their strength and vigor. (P. 53.)
Mountain Journeys 69
And yet they were only at a height of 8559 feet (2610 meters) ;
barometer 564 mm., temperature 17.5°.
September 2, they had passed the highest point of their journey,
10,032 feet (3056 meters), at the pass of Coochetopa, in Colorado;
they complained of no symptoms. (P. 47.)
The Reverend Hines 7:' made the ascent of Mount Hood in Oregon
with three companions, July 24, 1866. It was not without trouble,
as he says energetically:
We had only about 700 feet to go, but it taxed our sinews for two
hours to climb them. The sun was shining again, and the sweat was
dripping from our brows; but as we approached the summit, fatigue
seemed to disappear, and it was with a feeling of triumph that we
trod the summit of the highest mountain in North America. (P. 83.)
Hines was wrong on this last point; Williamson,74 who climbed
Mount Hood again in 1867, found its height to be only 3420 meters;
it is then not the highest of the Cascades, much less of North
America.
More recently, a very well-known English mountaineer, M.
Coleman, ascended mountains as high as or even higher than
Mount Hood.
In August, 1868, he climbed Mount Baker (3390 meters).75 In
his account he speaks only of sulphurous exhalations from which
he and his companions suffered; one of them was seized by vomit-
ing (P. 365). In August, 1870, ascent of Mount Rainier (4400
meters),70 on the summit of which he passed the night, warming
himself at the crevasses of the volcano, but much inconvenienced
by their exhalations: here too, no physiological trouble. But that
proves nothing, for we shall see, when we speak of the Alps, that
professional mountaineers today seem to make it a point of honor
never to speak of the sufferings of mountain sickness.
3. Etna.
In the preliminary chapter, I reminded the reader that the
ancients had frequently made the ascent of Etna (3313 meters);
but they have left us no record that might make us think that they
felt any extraordinary symptoms. The authors of the Middle Ages,
who followed their steps, and told of their own journeys, are no
more explicit than the ancients.
Pietro Bembo,77 who in 1494 made the ascent with his friend
Angelo Chabriele, does not even speak of his fatigue in his cele-
brated dialogue with his son. In 1540 and 1545, Filoteo climbed
Etna with several of his friends: he says nothing definite.78 Thomas
70 Historical
Fazello 7:' gives a few more details in the account of his ascent of
the 6th "of the Kalends of August", 1541; however he mentions
nothing but an extreme fatigue:
We had to climb on foot the crest of the mountain; the ascent was
very arduous; here, the roughness of the soil, there, deep sand delayed
us, our feet sliding backwards; in fact, the difficulties were so great that
although the climb was not more than 50 steps, it took us a good two
hours, and reaching the summit at last, panting and dripping with
sweat, we lay down on the ground. (Decas I, liber II, caput IV; vol. I,
P. 116.)
But a century later, in 1671, the illustrious doctor-mathematician
Borelli,8" whose attention had been aroused by the accounts of
travellers in South America, notes symptoms which he indicates
clearly:
Among the noteworthy observations which I made at the summit
of Etna in the year 1671, there is an unexpected effect due to the rare-
faction of the air. There, in fact, moderate movements . . . brought on
such lassitude, that young and robust men had to rest, to sit down,
and to regain their strength by breathing frequently. (P. 242.)
Then he tries to explain these symptoms; we shall see that he
gave successively two different theories for them. But the sensa-
tions which he had noted have not been experienced by all travel-
lers, and we see beginning here a series of apparent contradictions,
of which we shall mention numerous examples, even from our own
times.
In fact, Riedesel,81 in the account of his journey to Sicily, relates
his ascent of May 1, 1767, and he adds:
I did not find, as various travellers say, that the air was so rare-
fied and thin as to check or at least to hamper the breathing greatly;
which may depend, besides, upon the conformation and constitution
of the chest and the lungs of each subject who tries it. (P. 132.)
Demeunier,8- Houel,83 who made the same ascent at about the
same time, do not mention observing any symptom. Delon,84 when
he reached the summit of Etna, cried out enthusiastically:
An ethereal air which crushes him, startles his being, and makes
him realize an existence which warns man that he is out of the region
to which his organs chain him. He is impressed by his rashness. . . .
I leave to the reader the task of deciding whether this ranting
expresses any physiological phenomenon, and omitting other testi-
mony quite as unimportant, I come to the account of Dolomieu,83
who on June 22, 1781, made the ascent of Etna; the celebrated
Mountain Journeys 71
mineralogist was very severely affected, and his guide still more
than he:
The cold was cutting . . . often breath failed me, and I was forced
to stop short to get my breath, and to prevent strong palpitations which
I felt in the pulmonary arteries. . . . My guide constantly called to me
to walk more slowly, and when I reached the plain, near the Tower of
the Philosopher,*0 he told me that he could go no further, that he felt
very ill, and in fact, a moment afterwards, he fell unconscious, the
pallor of death on his face, and in a most pitiful state. ... A few drops
of wine made him revive a little; but he was very weak and like a man
about to die. (P. 98.)
Dolomieu continued his journey alone and reached the crater
without mentioning any real sufferings in his account; he speaks
only of his fatigue.
The report left us by Spallanzani of his ascent on September 3,
1788, is interesting particularly because of the record he gives of
the remarks of travellers who preceded him:
The rarefaction of the air on the summit of Etna did not produce
upon me the same effects as those experienced by some of the travel-
lers who had preceded me. Chevalier Hamilton (September 26, 1769)
felt his respiration hampered by the great thinness of the air; Count
Borch (October 16, 1776) was still more distressed; "the rarefaction of
the air on this mountain (he says) is very great, so great that the air
is hardly suited for breathing." Riedesel (1767), on the contrary, felt
no effects, or hardly any, as we see by this sentence: "I did not per-
ceive that the air was so rarefied as several travellers state, nor so thin
as to prevent breathing, or even to hamper respiration very much."
Brydone (May 27, 1770) does not mention it, and I concluded from his
silence that the thinness of the air did not tire him much.
As for me, my servant, and my two guides, the air gave us no
trouble. The difficulty of climbing . . . made our respiration painful
and hurried, it is true; but after we had reached the summit, after
resting a little, we soon regained our strength, and even while walking,
we had no further difficulty in breathing. (P. 272.) 37
The illustrious physiologist did not show his usual acuteness
there; he could not distinguish, as Borelli had done one hundred
years before, between the effects of walking and those in a resting
condition, and whatever he says, we can easily see that the air gave
him real, though slight, disturbances.
Ferrara,88 in his description of Etna, goes farther. According to
him, not only did the ascent cause no distress, but he breathed with
greater ease in this pure air:
The lessened density of the air, no less than its extreme purity,"
produced a full and free respiration. . . . We felt none of those symp-
72 Historical
toms which certain travellers say they experienced on the summit of
Etna; those symptoms must have been an effect of their poor physical
condition. We all felt very well. In his balloon, at the height of 21,482
feet, Gay-Lussac was in good shape. (P. 21.)
The French traveller De Gourbillon,89 who made the ascent
October 10, 1819, felt no effects himself; but that was not true of his
travelling companions:
M. Wilson experienced strange symptoms; his face, naturally ruddy,
was wan and pale, almost entirely livid. Though younger and more
nimble, and though he had not suffered as much from the volcanic
exhalations, which had produced upon the latter and even upon the
guide an effect like that of seasickness, my other travelling companion
seemed neither fresher nor less distressed. . . . Lazarus, when he left
the tomb, was no paler. (P. 436.)
Likewise, Count de Forbin,90 who mounted to the crater the
following year, was in very bad condition:
I was hardly halfway from the Tower of the Philosopher to the
summit, and already I was thoroughly disheartened. The rarefaction of
the air made breathing difficult; later, the oppression became very great,
it acted so much upon one of our travelling companions that he fainted.
He was revived, and summoning all our strength, we reached the high-
est crest of the crater after an hour and a half.
Never in my life had I felt such fatigue; . . . my first impression
was that I was like an invalid, prostrated, distressed by the terrors of a
feverish brain .... Weariness of the senses and excitement of the
imagination reduced us to a state nearly like delirium. (P. 173.)
About the same time, A. de Sayve made this ascent. The results
of it were told in a very interesting manner by H. Cloquet, who
made use of it to prove the effect of great heights upon the organ-
ism. He reported it to the Societe Philomathique in the following
words:91
In the month of January, 1820, M. H. Cloquet published some
details about the medical topography of Mont St. Bernard, and ideas
about the effect which a stay on the towering crests of lofty mountains
has upon man . . .
In spite of these data, a celebrated author of our time, M. Ferrara,
thought that only persons in poor health were inconvenienced while
ascending to the summit of Etna, in Sicily. A careful observer, M.
Auguste de Sayve, visited this famous place in the month of May,
1821, and disagrees with the learned M. Ferrara in this point. Here
are the principal results of the observations which he made, and M.
Cloquet considers that these results support what he has said ....
At the snow limit is the little plain called Piano del jrumento, at
the beginning of which are the ruins . . . known by the name of the
Tower oj the Philosopher . . . Even before reaching this point, M. de
Mountain Journeys 73
Sayve felt that he was breathing with difficulty; in spite of the cold,
he felt very acute thirst; however, a little rest restored his strength.
But the scene was to be changed .... The route passes by a
hut of refuge, which is at the foot of the cone, and which is the highest
building in all Europe (9,200 feet) .... From there up to the summit
there is only an absolutely bare cone, 1,300 feet high.
As our traveller climbed this cone of the crater, he felt his
distress increase, and was obliged to stop at nearly every step. He
felt extraordinary weakness in all his limbs; he was nauseated, and
thinking that he had left the element suited to his physical nature,
he tried, he says, to inhale a little air, but could not succeed at this
critical moment; and yet he was perfectly healthy when he began his
ascent; his passage through the region of snow had tired him very
little; the symptoms he felt can therefore be attributed only to the
rarefaction of the air.
M. Aubert-du-Petit-Thouars . . . told the author that he had
felt similar symptoms, especially a weakness in the stomach, when he
climbed the mountain in the He de Bourbon, known as the Benard.
M. Cloquet, moreover, himself experienced symptoms of this sort,
when he reached a certain height in the Alps ....
M. de Sayve had with him a companion who was much more
severely affected; and we know that the unfortunate Dolomieu, in the
same ascent, was also attacked by symptoms like those which we have
just mentioned ....
These different symptoms are quite varied and appear sooner in
some persons than in others; but they cannot be attributed to fatigue,
which never has such consequences in mountains of an elevation less
than 1,000 fathoms.
Moreover, they appear alike in animals and men.
I shall not give more quotations. More recent authors show the
same differences in power of observation, and most of them say
nothing about physiological disturbances. What I have reported is
enough to show that Etna is, if I may use this term, a limited
mountain, in the ascent of which many persons experience no
painful symptom, whereas others are more or less ill. Since the
first symptoms of distress are exactly those of excessive fatigue,
the difficulties of the ascent of the cone are consequently enough
to explain everything, in the opinion of most of the travellers;
some think the cause of the oppression is the poisonous exhalations
coming from the volcano through the innumerable fissures in the
ground. It is not surprising, then, that before verification of the
disease peculiar to mountains, in the main range of the Andes,
nothing unusual was noted in ascents of Etna.
4. Peak of Teneriffe.
Discovered again in the fourteenth century by French navi-
gators, the Canary Islands were conquered in the fifteenth century
74 Historical
by the Spaniards. But for a long time no one dared attempt the
ascent of the volcano, the summit of which seemed all the higher
because its foot is at sea level.
The strangest and most exaggerated estimates were made of its
height. According to Th. Nicols,92 it was not less than 15 leagues;
Riccioli and Kircher estimated it at ten Italian miles; in reality, it
is 3716 meters.
The first account of its ascent 93 that we have found is that of a
journey made in 1652 by some "notable merchants and men of great
esteem"; they were considerably affected by the rarefied air:
At six o'clock in the morning we began to ascend the Peak . . .
Some of our company became very weak and sick, and were attacked
by diarrhea, vomiting, and feverish trembling . . . One of us was
so ill that he could go no further. (P. 201.)
The celebrated Robert Boyle °4 reported a similar account, in
which the effect of the expanded air is confused with that of emana-
tions from the earth, as often happens in ascents of volcanoes:
One day I asked an intelligent man who had lived for several
years in Teneriffe whether he had climbed to the summit of the Peak,
and what sensations he had had. He replied that he had tried, that
several of his companions had completed the ascent, but that the thin
air and the sulphurous exhalations had made himself and a few others
so sick that they halted far below the summit. The effect of these
vapors was such that his skin became pale yellow, and his hair was
bleached. (P. 2039.)
Not all travellers experienced the same effects, and, as usual,
those who were free from distress were led to deny what their less
fortunate predecessors reported.
Edens,95 who ascended the Peak in 1715, expresses himself as
follows:
What has been said about the difficulty of breathing on the summit
of the Peak seems wrong; we breathed as easily up there as we did
below; we had our lunch there. (P. 186.)
Father Feuillee u0 made the ascent of the Peak on July 31, 1724;
he says nothing of interest to us.
G. Glas 97 was less fortunate:
We reached the foot of the cone (he says in fact) . . . Although
the distance is hardly a half mile, we were forced to stop forty times,
I think, to get our breath, and when we had reached the summit, it
was a quarter of an hour before we had recovered. (P. 255.)
The same thing was true of the scientists whom Labillardiere ,J8
had taken with him on his journey in search of La Perouse:
Mountain Journeys 75
Citizens Riche and Blavier (he says) had undertaken the ascent
of the Peak one day after us (Labillardiere, who made the ascent
October 17, 1791, speaks of no painful sensation) ; but these two
naturalists did not succeed in climbing to the summit; they were
still far from it when they spat blood, since their lungs could not
become accustomed to the rarefied air, and they were forced to give up
their undertaking. (Vol. I, p. 27.)
It is true that, according to Bory Saint-Vincent,"
Riche was in very poor health and had very weak lungs .... He
died as a result of his journey, soon after his return to France. (P. 182.)
Von Humboldt100 (ascent of June 21, 1799) says absolutely
nothing of physiological disturbances.
The celebrated geologist Cordier,101 who ascended the Peak
April 16, 1803, discusses these disturbances, but only to deny them,
or practically so:
What has been said of the keenness of the cold, . . . and the
difficulty of breathing on the Peak is not correct. Moreover, I have
already proved several times that the opinion generally held in this
respect is more than exaggerated; I assure you that the cold was quite
endurable . . . that the rarity of the air did not inconvenience us at all,
although it forced us to halt quite frequently as we approached the
summit. (P. 61.)
The illustrious Leopold de Buch, in the accounts of his ascents
of May 18 and 27, 1815, 102 does not give them a more important
place:
The ascent becomes more difficult after the Estancia de los
Ingleses ... In spite of that, the difficulties are not comparable to
those of an ascent to the summit of one of the snow covered peaks,
of the Alps .... When we reached the crater, we suddenly saw
appearing opposite us Mme. Hammond, a Scotch lady, with her trav-
elling companions. She was the first woman ever to ascend to the
summit. (P. 4.)
May 27 we again ascended the Peak. (P. 5.)
The account of Dumont d'Urville 10a is very interesting in its
brevity. He passed the night, in June, 1826, at the Estancia de los
Ingleses:
The air was very pure (he says) and I felt none of these violent
disturbances and these suffocating sensations experienced by different
travellers. M. Quoy alone had pains in the stomach, and M. Gaimard
slept all night without any trouble .... The next day, as we
approached the Pain-de-Sucre, we were obliged to stop frequently
to get our breath .... We lunched gayly on the crest of the Piton.
(P. 37.)
76 Historical
At the time of his second journey, in October, 1837, the officers
of the Astrolabe and the Zelee made the ascent of the Peak.
Dumont d'Urville 104 reports their sensations in these words:
In agreement with my observations in 1826, MM. Dumoulin and
Coupvent noted .... the numbness of the extremities of the body.
During the night, the thermometer dropped to — 0.5°. MM. Dubouzet,
Dumoulin, and Coupvent, especially the latter, felt severe headaches.
(P. 32.)
The surgeon, Le Guillou,105 reporting the same ascent, says:
Several of our comrades were afflicted by a strange symptom;
they had copious nosebleeds, and we were forced to stop a few
moments. (P. 29.)
On September 18, 1842, ascent of M. Charles Sainte-Claire De-
ville; 10G he does not say a word about physiological disturbances.
Itier,107 who climbed the Peak December 28, 1843, gives more
importance than his predecessors to the sufferings he felt:
We left the Estancia d'Ariba (3104 meters), and mounted on foot
the sort of path which winds between two flows of obsidian; walking
is painful among these fragments of pumice stone mingled with ashes
which give under the foot; besides, the sun began to affect us, and
the effect of the rarefaction of the air soon added to the fatigue of
our effort. My heart throbbed violently, and the arteries of my brain
shared in this distress; the headache it caused forced me to stop
frequently; my companion, less accustomed to mountains than I, felt
these effects much more than I did; he stopped every ten steps,
suffocating, exhausted. (Vol. I, p. 28.)
I shall quote finally the account reported from the notes of a
traveller by Madame Elizabeth Murray, an English artist,108 of an
ascent of the Peak, made in August, by four Englishmen and an
American:
To pass the night, we made our bivouac at the Estancia de los
Ingleses, at a height of 9933 feet. (Vol. II, p. 20.) ....
One of us was seized by extreme weakness, shivering, and
violent headache; we covered him with rugs, lighted a good fire,
and the heat, added to the effects of a little liquor, partially revived
him. (P. 121.)
It was late, and we stretched ourselves on the ground, wrapped
in our rugs. Shortly after, my companion on the right rose and
complained bitterly of extreme cold, pains, and distress in his stomach.
We placed him near the fire, and gave him warm water and brandy.
He began to be well enough to permit us to sleep when my
neighbor on the left was attacked, then treated in the same way.
Both suffered severely from the symptoms well known to ocean
voyagers; these symptoms are not rare on the Peak; they are some-
times attributed to sulphurous exhalations, but I think that they are
Mountain Journeys 77
caused instead by the rarity of the air. At any rate, we smelled no
odor of sulphur.
Of the four of us, my American friend and I were the only ones
who felt no discomfort. (P. 123.)
Before arriving at the Rambleta (11,680 feet), many of us suffered
more or less from difficulty in breathing. One of my companions, in
particular, could not take more than eight to ten steps without
stopping, thus forcing us to wait for him. (P. 126.)
After a great many halts to regain our breath, we reached the
summit. (P. 128.)
We went back by the "Mai Pais", the descent of which was as
disagreeable as the ascent, except that our respiration was much
freer. (P. 136.)
In summary, the Peak of Teneriffe is, like Etna, a limited moun-
tain, in the ascent of which many travellers feel no great effects,
those who are ill being only slightly affected.
5. Alps.
It is not until the end of the last century that ascents were made
in the Alps to heights sufficient to bring on physiological disturb-
ances. Until the time of Canon Bourrit and the illustrious De Saus-
sure, only a few chamois hunters had ventured above the line of
perpetual snow. The main peak of Mont Blanc, today traversed in
all directions every year by hundreds of tourists, bore the sig-
nificant name of the Accursed Mountains; in the seventeenth cen-
tury, the Bishop of Annecy, Jean d'Aranthon,100 came to exorcise
its glaciers, which withdrew submissively after his benediction. Of
the rival summits of Monte Rosa and the Jungfrau, there was no
question. The principal passes had been frequented since the days
of the Romans; many armies had crossed them; the hospice of the
Grand Saint-Bernard was founded at the end of the tenth century,
but no one had thought of risking his life in the ascent of one of
the innumerable summits which tower above the beautiful Alpine
valleys: in 1740, the first Englishmen arrived at Montanvert!
However, it was well known that travellers suffered sometimes,
in crossing the Alps, from pulmonary disturbances. Haller con-
siders them, as we shall see in the chapter devoted to the discussion
of theoretical explanations; he even speaks of hemoptyses observed
by Scheuchzer: "ut in primis in J. Sch. triste exemplum exstat".110
I could not secure the work of this German geographer; m but
according to Meyer-Ahrens,112 he must have experienced only the
oppression and threats (Vorboten) of hemorrhage.
The first traveller who has given us an account of personal dis-
agreeable sensations, the second to make the ascent, today so com-
78 Historical
mon, of Buet (3110 meters) is the Canon Bourrit.1 i;i At this
moderate height, he experienced strange symptoms'.
In 1776, I left Geneva with the purpose of ascending Buet; it
was the second time that I had climbed this mountain; .... I was
in good physical condition .... All three of us reached the summit
feeling very well .... After ten minutes of peaceful halt, I felt a
numbness in my arms and legs, and soon I had not the strength to
force myself out of this condition; I was already unconscious when
my companions removed me; they carried me down to the first rocks
of the glacier ....
The next year, .... I went there in very fine weather; ....
I began to sketch, and told my guide to hold my parasol over me.
After 15 minutes, I noticed that he was not holding it well; . . . ,
and you can imagine my surprise when I saw this man as white as
snow .... and his eyes almost motionless; I made the utmost haste to
get him away from this baneful summit .... Finally, in 1777, ....
M. Saint-Ours .... witnessed a similar attack on the summit of
Buet .... (Vol. II, p. 94.)
Bourrit, however, seems to have been quite subject to syncopes;
he reports two others, one on the glacier of Buet, while he was
walking (Vol. Ill, P. 198), the other during his attempt to ascend
Mont Blanc, September 11, 1784 (Vol. Ill, P. 300 and 304).
At a still lower elevation, at the monastery of the Grand Saint-
Bernard (2430 meters) , a traveller of the same period, Laborde, felt
similar symptoms, although considerably less severe:
The sky was clear when we reached the monastery of the Grand
Saint-Bernard (July 30, 1777).
It would be difficult to express the different sensations which
one feels at the same time; the first that is noticeable is an attack
caused by difficulty in breathing; it seemed as if the lungs did not
have their usual elasticity and lacked the capacity to hold the air
inspired; the difference between the air one breathes at such a
height must be very evident to those who are used only to air of the
plains; it is more rarified and purer because it is less filled with
vapors (Lecture on the natural history of Switzerland, P. VIII).
These few quotations bring us to the celebrated accounts of De
Saussure; the sufferings experienced at elevations which are very
low compared with Mont Blanc, the ascent of which he dared to
attempt and carry out, bring out still more the bravery which he
displayed in this intrepid undertaking. Canon Bourrit, when he
said, as we shall see in Chapter III, that it would be difficult, if noi
impossible to live long on the summit of Mont Blanc, only trans-
lated, in a somewhat modified form, an opinion universally held by
mountaineers.
De Saussure, when he ascended Mont Blanc, had prepared for it
Mountain Journeys 79
by numerous expeditions made every year on lofty mountains.
Now at fairly moderate heights he had already felt symptoms,
which had attracted his attention. In the account of his ascent of
Buet, made July 13, 1778, in the company of Pictet, he gives l15 a
very clear indication of it:
The rarity of the air, as soon as one passes the elevation of
1300 to 1400 fathoms above sea level, produces very strange effects
upon the body.
One of these effects is that muscular strength is exhausted very
quickly. (Vol. I, p. 482.) ....
Another effect of this thin air is the drowsiness it produces. As
soon as one has rested for a few moments at these great heights,
he feels his strength entirely restored, as I have said; even the
impression of the former fatigue seems wholly effaced; and yet in
a few moments one sees all who are not busy, falling asleep, in
spite of the wind, the cold, and the sun, and often in very uncomfort-
able positions. Of course fatigue, even on the plains, produces sleep;
but not so suddenly, especially when it seems to have entirely
disappeared, as it does on the mountains, as soon as one has rested
a few moments.
These effects of the thinness of the air seemed to me quite
universal; some persons are less subject to it; the dwellers on the
Alps, for example, who are accustomed to living and working in
this thin air, seem less affected by it; but they do not entirely escape
its effect. The guides, who on the lower slopes of the mountains can
climb for hours at a time without stopping, have to pause to get their
breath every 100 or 200 steps, as soon as they are at an elevation of
1400 or 1500 fathoms, and as soon as they have halted for a few
moments, they too fall asleep with surprising promptness. One of
our guides, whom we had standing on the top of Buet with a parasol in
his hand so that the magnetometer might be in the shade while M.
Trembley observed it, kept falling asleep constantly in spite of the
efforts which we made and which he made himself to struggle
against this drowsiness. And on my first trip to Buet, Pierre Simon,
who had crept into a snow crevasse to shelter himself from a cold
north wind which distressed us greatly, went sound asleep there.
But there are constitutions which this rarity of the air affects still
more severely. One sees men, very sturdy elsewhere, consistently
attacked at a certain elevation by nausea, vomiting, and even fainting,
followed by an almost lethargic sleep. And all these symptoms cease
although fatigue continues as soon as they have reached a denser air
in the descent.
Fortunately for the progress of physics, M. Pictet is not so
seriously affected by the thinness of the air; however, he is more
affected than the average man, for although he is very strong, very
nimble, and well trained in climbing mountains, he is always attacked
by a sort of distress, a. slight nausea, and an absolute loathing of
food, as soon as he reaches the elevation of 1400 fathoms above sea
level. As for me, I feel no effect other than being obliged to rest very
80 Historical
frequently, when I ascend steep slopes at these great heights. I tested
this again in my last trip to Buet. While we were climbing the slope
covered with soft snow which crowns the mountain, I absolutely had
to stop every fifty steps, and M. Pictet, more sensitive than I to this
effect of the rarity of the air, counted his steps without telling me,
and found that he could not take more than forty without getting his
breath. (P. 483-85.)
But that was nothing compared to what he was to observe in his
trip to Mont Blanc. Already several attempts had been made to
reach the summit of this colossal mountain. De Saussure recorded
for us the account of these vain attempts, and it is clear that the
physiological symptoms experienced by those who made these at-
tempts had much to do with their failure:
§1103. In 1775, four guides from Chamounix tried to reach the
summit by the mountain of La Cote .... Everything seemed to
promise them perfect success; .... but the reflection of the sun upon
the snow and the stagnation of the air in a great valley of snow
which seemed to lead them directly to the crest of the mountain
gave them a feeling of suffocating heat, as they said, and at the same
time gave them such distaste for the provisions with which they were
supplied, that, worn out with lack of food and weariness, they
retraced their steps. (Vol. II, p. 550.)
§1104. In 1783, three other guides made the same attempt by the
same route. They passed the night at the top of the mountain
La Cote, crossed the glacier, and followed the same valley of snow.
They were already fairly high and were advancing courageously,
when one of them, the most daring and sturdy of the three, was seized
almost suddenly by an absolutely unconquerable desire to sleep; he
wanted the other two to leave him and go on without him; but they
could not consent to abandon him and leave him sleeping on the snow,
convinced that he would die of sunstroke; they gave up their attempt
and returned to Chamounix. For this need of sleep, produced by the
rarity of the air, ceased, as soon as he was in a denser atmosphere in
the descent .... The heat gave them all great distress; they had no
appetite; the wine and the food which they took with them had no
attraction for them.
September 13, 1785, De Saussure himself attempted the ascent
with M. Bourrit and his son. He slept at the hut (1422 fathoms) :
§1112. M. Bourrit and his son even more than he were a little
affected by the rarity of the air; they did not digest their dinner well,
and could eat no supper. As for me, since the thin air inconveniences
me only when I am exercising violently in it, I passed an excellent
night there.
The next day, he mounted to an elevation of 1900 fathoms; the
snow stopped him.
But the ascent of Mont Blanc had become a dominating idea in
Mountain Journeys 81
him. The next year, he commissioned Pierre Balmat to construct a
hut at the foot of one of the crests of the needle of Goute, so that he
might rest there before trying next to mount to the summit of
Mont Blanc:
§1963. In executing this project, Pierre Balmat, Marie Coutet,
and another guide, June 9, 1786, .... reached the summit of the
needle of Goute, after having all of them been extremely ill from
fatigue and the rarity of the air. (Vol. IV, p. 138.)
It was in consequence of this trip that Jacques Balmat, who had
rejoined his compatriots and who passed the night on the mountain,
found the route to Mont Blanc by the Corridor:
§1965. This route had already been tried but had been discarded
because of a strange prejudice. As it follows a sort of valley between
eminences, it was imagined that it was too warm and had too little
air ... . Fatigue and the rarity of the air caused in those who made
the first attempts this prostration of which I have often spoken; they
attributed this distress to the heat and the stagnation of the air, and
tried to reach the crest only by uncovered and isolated ridges.
The people of Chamounix also believed that sleep at these great
heights would be fatal; but the test which Jacques Balmat made by
passing the night there dissipated this fear. (Vol. IV. p. 140.)
It seems as if the account given by De Saussure of the discovery
of Jacques Balmat is not exactly correct. The illustrious physicist
of Geneva seems to have been led astray by his favorite guides,
who, jealous of Balmat, attributed to chance what was the fruit of
long and persistent research. The interesting works of M. Ch.
Durier have cast some light on this point. At any rate, June 10,
1786, Jacques Balmat, having found the true route, after several
nights passed on the mountain, descended to Chamounix almost
dying of fatigue and cold. Being attended by Dr. Paccard, he in-
formed him of his discovery and proposed to share the glory of it
with him by making the ascent with him. Paccard accepted, and
on August 9, 1786, a human foot for the first time trod the summit
of the highest mountain of Europe. Dr. Paccard had been ex-
hausted by fatigue and no doubt also by the rarefaction of the air
so that he stopped on the way and lay down; Balmat ascended
alone, then returned to seek his companion, half carried him to the
crest, and took him back down blinded by the snow.
Unfortunately I have not been able to get an authentic account
of this memorable ascent. That of Alexandre Dumas (Impressions
de voyage en Suisse, Chap. X) , much less inexact than one would
expect, cannot, however, be trusted in physiological matters. But
what has been said and written about this journey shows that the
82 Historical
two companions, especially Dr. Paccard, suffered keenly from the
rarefaction of the air.
At the news of the success, De Saussure, who had promised a
prize to the person who should find the true way, though hoping to
use it first himself, made haste to organize a new expedition. But
judging that the season was too advanced, he had to put off until
the following year the realization of a desire which had interested
him deeply for so many years.
August 1, 1787, he left Chamounix, accompanied by a servant
and eighteen guides. He slept under the tent on the summit of the
mountain La Cote.
The evening of the second day of the ascent, he reached the
little' plateau; the barometer registered 17 inches 10 lines. They
made preparations to pass the night (1995 fathoms) :116
§1962. There (says De Saussure) my guides first began to exam-
ine the place in which we were to pass the night; but they very
quickly felt the effect of the rarity of the air. These sturdy men, for
whom the seven or eight hours of walking which we had just done
were absolutely nothing, had hardly lifted five or six shovelfuls of
snow when they found it absolutely impossible to continue; they had
to relieve each other constantly ....
I myself, who am so accustomed to the air of the mountains, who
feel better in this air than in that of the plain, was completely
exhausted while examining my meteorological instruments. (Vol.
IV, p. 144.)
The next day they continued to ascend, and reached "the cliff
which forms the left shoulder of the crest of Mont Blanc":
§1985. When I began this ascent, I was already quite out of
breath from the rarity of the air ... . The kind of fatigue which
results from the rarity of the air is absolutely unconquerable; when
it is at its height, the most terrible danger would not make you take
a single step further. (P. 165.)
Soon they were no more than 150 fathoms in elevation from the
summit of Mont Blano: .
§1988. I therefore hoped to reach the crest in less than three
quarters of an hour; but the rarity of the air gave me more trouble
than I could have believed. At last I was obliged to stop for breath
every fifteen or sixteen steps; I usually did so standing, leaning on
my alpenstock, but about once out of every three times I had to sit
down. This need of rest was absolutely unconquerable; if I tried
to overcome it, my legs refused to move, I felt the beginning of a
faint, and was seized by dizziness quite independent of the effect of
light, because the double crape which covered my face protected my
eyes perfectly. Since it was with keen regret that I saw thus passing
the time which I hoped to devote to my experiments on the summit,
Mountain Journeys 83
I made different tests to shorten this rest; I tried, for example, not
to continue to the end of my strength, and to stop an instant every
four or five steps, but I gained nothing; I was obliged, after fifteen
or sixteen steps, to take a rest as long as if I had made them consec-
utively; and this was very noteworthy, that the greatest distress
is not felt until eight or ten seconds after one has stopped walking.
The only thing that did me any good and increased my strength was
the cold air of the wind from the north; when as I climbed I had
my face turned in that direction, and swallowed great mouthfuls of
the air coming from it, I could take twenty-five or twenty-six steps
without stopping. (P. 171.)
At last the highest crest was reached:
§1991. I now had to make the observations and experiments,
which alone gave some value to this journey; and I was terribly
afraid that I should be able to do only a small part of what I had
planned. For I had already found, even on the plateau where we
had slept, that every observation made carefully tires one in this
thin air, and that is because, without realizing it, one holds his breath;
and since there one must compensate for the rarity of the air by the
frequency of his breathing, this suspension caused definite distress; I
was obliged to rest and to pant after observing any instrument as
after making a steep ascent. (P. 175.)
What De Saussure had foreseen happened:
§1965. When I had to get to work to set out the instruments and
observe them, I was constantly forced to interrupt my work and
devote myself entirely to breathing ....
When I remained perfectly quiet, I felt only slight distress, a
little tendency to nausea.
But when I took pains, or when I fixed my attention for a few
moments consecutively, and especially when I compressed my chest
by stooping, I had to rest and pant for two or three minutes. My
guides experienced similar sensations. They had no appetite. (P. 147.)
§2021. Some could not endure all these kinds of sufferings, and
descended first to reach a milder air. (P. 208.)
Farther on, De Saussure makes a very accurate statement, which
explains many exaggerations and many doubts:
§2021. I observed a rather curious fact, that for some individuals
there are perfectly - marked limits, where for them the rarity of the
air becomes absolutely unendurable. I have often taken with me
peasants, elsewhere very robust, who at a certain height were sud-
denly so affected that they absolutely could not ascend higher; and
neither rest, nor cordials, nor the keenest desire to reach the crest
of the mountain could make them pass this limit. They were attacked,
some by palpitations, others by vomiting, others by faints, others by
a violent fever, and all these symptoms, disappeared as soon as they
breathed a denser air. I have seen persons, but only a few, whom
these symptoms forced to stop at eight hundred fathoms above sea
84 Historical
level; others at twelve hundred, several at fifteen and sixteen hun-
dred; as for me, like most of the dwellers on the Alps, I do not begin
to be noticeably affected until at nineteen hundred fathoms; but
above this limit, the best trained men begin to suffer when they hurry
a little. (P. 209.)
Finally they had to descend; from eleven o'clock to half -past
three, De Saussure remained on the summit, and he was sorry to
leave, because, he says, and I call the attention of the reader to
this extremely important remark:
§2021. Although I had not wasted a single moment, in these
four hours and a half I could not make all the experiments which I
had frequently finished in less than three hours at sea level . . . But
I kept the well founded hope of finishing, on the col du Geant, what
I had not done, and what probably no one will ever do, on Mont
Blanc. (P. 210.)
The descent was accomplished successfully and without great
fatigue:
As the movement one makes while descending does not compress
the diaphragm, it does not hamper respiration, and one does not
suffer from the rarity of the air.
The example of the illustrious physicist was soon followed.
Seven days after his famous ascent, the English colonel Beaufoy 117
in his turn reached the summit of the giant of the Alps. It was not
without keen sufferings, as the following extracts from his account
prove.
Leaving Chamounix August 8, 1787, he slept with his ten guides
at the hut built in 1786 by the orders and at the expense of M. de
Saussure. The first physiological phenomenon which the colonel
mentions is thirst:
Our thirst, since we had reached the upper regions of the air,
had become unendurable. Hardly had I drunk when my mouth was
dry. Although I was drinking constantly, the quantity of my urine
was very small; its color was very dark. The guides were similarly
affected; they did not wish to taste wine ....
The rarity of the air soon began to give me a violent headache;
to my great surprise, I also felt a keen sensation of pain just above
my knees ....
When we were within .150 fathoms (270 meters) of the summit,
the harmful effects of the rarity of the air was evident in all of us;
an almost irresistible desire to sleep possessed us. My energy had
left me; indifferent to everything, I thought only of lying down on the
ground; at other times, I regretted this expedition, and when I was
almost at the summit, I thought of descending, without doing it how-
ever. Many of my guides were in the most pitiful condition; exhausted
Mountain Journeys 85
by excessive vomiting, they seemed to have lost both strength of
body and strength of mind. But shame came to our assistance. I
drank the last pint of water and felt refreshed. Yet the pain of my
knees had so increased, that every 20 or 30 steps I had to stop until
its acuteness had diminished. My lungs did their duty with difficulty,
and my heart throbbed with violent palpitations. Finally, however,
but with a sort of apathy which barred joy, we reached the summit.
Six of my guides and my servants immediately threw themselves
down with their faces against the ground and went to sleep. I
envied their repose.
The colonel suffered greatly from the reflection of the sun upon
the snow; he had neither veil nor glasses.
Some weeks later, De Saussure, in his ascent of Mont Cenis,
September 28, 1787, again made very interesting remarks from the
physiological point of view:
§1280. At our departure from the summit, where we had stayed
for two hours, I counted by my watch with a second-hand the pulse
rate of all those who composed our little caravan, and counted it
again on our arrival at the post-house of Mont Cenis:
J. B. Borot, guide, above 112, below 100
B. Boch, guide above 112, below 96
J. Tour, guide above 80, below 88
Tetu, my servant, above 104, below 100
My son above 108, below 108
Myself above 112, below 100
Average above 104% below 98%
It will be noted that Joseph Tour was the only one whose pulse rate
was higher at the foot of the mountain than at the top; that for my
son, the number was the same, and that the other four had a more
rapid rate on the summit, so that the average gives six beats per
minute more above than below, with a difference of about 4 inches
2 lines in the height of the barometer. There is this also to be noted
that after I counted the pulse rate on the mountain after a stay
amounting to a rest of at least two hours for the guides; whereas on
the plain, as they wished to leave, I had to count it a few minutes
after our arrival.
What is still more remarkable is that when I separate those who
were nauseated (three of the four guides, whose names De Saussure
does not give, were nearly sick on the summit) from those who
remained well, I find that the average difference was 9V3 for the
first, and only 2% for the second. This observation confirms what
I have always believed, namely, that this discomfort partly resembles
a sort of fever, produced by the frequency of the breathing, which
quickens the circulation of the blood. And as for me, if my pulse
was a dozen beats more above than below, even though I felt no
discomfort, that is because I did not rest a single moment; I was at
work continually during these two hours; if I had rested like those
86 Historical
who were ill, I am sure that my pulse rate would have dropped
several beats. (Vol. Ill, p. 85.)
The following year, he went with his son to stay on the col du
Geant (3360 meters) from July 3 to July 19, 1788; this trip, which
filled the guides with terror, was undertaken with the purpose of
attempting experiments which, on Mont Blanc, "the shortness of
the time and the discomfort caused by the rarity of the air pre-
vented me from carrying out." (Vol. IV, p. 217.) One whole
very interesting chapter is devoted to Observations Relating to
Physiology:
§2105. It was interesting to note what effect upon our bodies
would be caused by a prolonged stay in an air as rarified as that
which we were breathing on the Col du Geant. It must be recalled
that the average height of the barometer was, during our stay, about
19 inches, that is, 9 inches lower than at sea level, and that therefore
the density of the air there was nearly one third less.
M. Odier, a doctor in medicine, very eager for the progress of his
profession, had given me some questions which were to serve as text
for my observations.
§2106. To determine precisely the degree of animal heat. During
the morning of July 17, at a moment when I was very calm, and
without having made any violent movement, I placed under my
tongue a small mercury thermometer keeping my mouth closed, and
at the same time I observed this thermometer with a magnifying
glass. It was at 29 Vz, and registered the same degree under the same
circumstances on the plain.
To count the number of inspirations and expirations which a man
in repose and not forewarned makes in a minute, and also the rela-
tion of this number to that of the pulse rate. Under the same circum-
stances as those of the preceding paragraph, at first I found 75 heart
beats for each inspiration and as many for each expiration. But
another time, taking a larger number, which for that very reason
deserves greater confidence, I found that I made 10 inspirations and
expirations in 35 seconds, which amounts to 17 per minute, and that
my pulse rate was also 79 per minute.
§2107. To try to inspire deeply enough to stop the pulse in the
left wrist, supposing that the same individual can do so on the plain.
July 19, when I arose, seated on my pallet, I succeeded in stop-
ping the pulse of the left wrist, prolonging the inspiration for ten
seconds; immediately I repeated the test, and the pulse stopped at
the fifteenth second; the third time, at the thirty-fifth second the
pulse was still resisting when I was forced to catch my breath. When
I made the same test standing, I could not stop my pulse; but it is
true that I could prolong the inspiration only for 32 seconds. Therefore
this test appears, at least for me, not susceptible of regular com-
parison.
§2108. To count the pulse in a perfectly vertical position; if the
Mountain Journeys 87
difference is greater than on the plain, it is a proof that the air of
lofty mountains increases the irritability of the heart.
July 18, in the afternoon, having taken a short nap on my pallet
on the ground, in a horizontal position, my pulse rate in this same
position was 83 per minute. I then arose, and while standing, my rate
was 88; but suspecting that the effort which I had made in rising
might have contributed to this acceleration, I rested a few instants,
and then my pulse rate was only 82.
§2109. To determine by comparison whether the inspiration can
be held as long on the mountain as on the plain.
In section 2104 I reported the attempts I had made on the moun-
tain. I then forgot to repeat them on the plain on my return, and
since then, my constitution has been so much affected by fatigues
and illnesses, that the comparative tests I might make would give
no result on which one could reason.
To determine* if it is possible comparatively, the proportion of
the urine to the amount drunk. We lacked the necessary facilities to
make comparisons.
§2110. To verify particularly whether the effects of the rarified
air appear suddenly or gradually.
It appeared to us that the general effects were almost the same
during our whole stay. When we arrived, we were all more out of
breath than we should have been after making an ascent equal to
that on a less lofty mountain on the last day. On the following days,
the discomfort was far from increasing; our companions, my son,
and I thought that we were becoming accustomed to this air: how-
ever, when we gave attention to it, and especially when we made
efforts for this purpose, we found that if one ran, if he remamed in
an uncomfortable attitude, and particularly in a position in which
the chest was compressed, one was much more out of breath than on
the plain, and in an increasing progression; so that, from moment
to moment, it became more difficult, and at last even impossible to
keep up these efforts.
§2111. As our observations forced us to remain in the open air
almost all day, I had advised my son and my servant always to keep
a piece of crape over the face, as I did myself. My servant thought
that he could do without it, but his whole face, and particularly his
lips, swelled, which made him hideous, and which was accompanied
by very painful cracking of the skin. That made my son think that
perhaps the action of the sun produced a liberation of air which
caused this swelling.
To see whether this air would appear outside, he had this same
young man hold his hands in water in the sun; they were immediately
covered with little bubbles; he wiped them, then when he put them
back in the water, more bubbles appeared; he wiped them a second
time, and dipped them for the third time; but then there were no
more bubbles to be seen. We concluded from that, that the bubbles
which we had seen at first were only air adhering to the surface
of the skin.
2212. It seemed to us that in general our nerves were more
irritable, that we were more subject to impatience, and even to
88 Historical
impulses of anger; our tempers were noticeably worse; hunger
appeared more disturbing and more imperious; but on the other hand
our appetites were more easily satisfied and digestion seemed to take
place more rapidly than on the plain. Moreover, it seemed to my
son and me that in our work and our observations relating to
physics, our minds were noticeably freer, more active and less easily
tired, I will even say more inventive, than on the plain, and I hope
our readers will find the proof of it in the report of our occupations
during these seventeen days. (Vol. IV; p. 315-318.)
In his trip around Monte Rosa he also describes the distress felt
by animals. On August 14, 1789, he was on the glacier of Mont
Cervin (glacier Saint-Theodule) :
2220. The mules, which were sinking in the snow up to their
girths, were unloaded; yet it was very hard for them to go on, they
were panting, obliged to stop for breath, as soon as they had made a
few steps. However the grade was not very steep, and the three or
four hours of walking which they had had could not have tired
them .... but it was the rarity of the air which affected them; they
experienced all that we had experienced when we ascended Mont
Blanc .... The breathing of these poor animals was extremely
painful, and at the very moments when they were stopping for
breath, they panted with such distress that they uttered a kind of
plaintive cry which I had never heard, even when they were very
weary. It is true that I had never travelled with mules at so great
an elevation .... we were then 1,736 fathoms above sea level. (Vol.
IV, p. 380.)
Canon Bourrit, whose vain attempts had preceded the expedition
of De Saussure, made the ascent of Mont Blanc in 1788, accom-
panied by Woodley and Camper. I have not found any complete
description of this trip. But we owe to him a few details of a
somewhat later expedition, made August 11, 1802, by Forneret and
Dortheren:
The rarity of the air (he says)113 added to the difficulty of walking;
their chests felt lacerated, and they told me that nothing on earth
would induce them to undertake such an attempt again. (P. 431.)
On July 14, 1809, the first ascent of Mont Blanc by a woman,
Marie Paradis, a maid-servant at Chamounix. She was so ex-
hausted at about the elevation of 4600 meters, that the guides who
accompanied her were forced to hold her up and carry her to the
crest.
From 1809 to 1816, only one ascent (Rodaz, 1812) about which
we have no information.
A German officer, Count de Lusy, left Chamounix September 14,
1816, to ascend Mont Blanc; he had eight guides with him. From
Mountain Journeys 89
the German pamphlet of Hamel, from which I shall quote presently,
since I was unable to secure the account of Lusy,119 I borrow the
references to the serious symptoms which attacked them:
Near the summit, some of the travellers felt nausea and a strong
desire to sleep; three bled from the nose and one from the mouth;
that did not stop Count Lusy. (P. 36.)
August 4, 1818, Count Malazesky, a Pole,120 then van Rensselaer
of New York on July 11, 1819, also undertook this difficult enter-
prise. The report of the latter, although quite detailed,121 contains
no suggestion of any interesting physiological fact; his companions
and he experienced only a great acceleration of respiration and
pulse accompanied by loss of appetite.
Then, in 1820, Dr. Hamel,122 court counselor of His Majesty the
Emperor of all the Russias, made the ascent in the company of
Colonel Anderson. His trip was interrupted near the summit by a
terrible catastrophe, which took the lives of three guides, dragged
down in an avalanche.
He first made on August 3 an unsuccessful attempt:
We started from Saint-Gervais and passed the night at Pierre-
Ronde, sheltered by a few rocks.
The next day at 11:30 we reached the summit of the Dome du
Goute ....
It was on this two hour march that for the first time I expe-
rienced the effect of the rarified air upon my strength. It was abso-
lutely impossible for me to take more than forty steps without stopping
about two minutes to get my breath; and when I reached the summit
of the Dome (2,200 fathoms), I felt so exhausted that I should have
needed at least a half-hour's rest if I were to be able to go on to the
crest of Mont Blanc. After I had made my calculations, I found that
it would be absolutely impossible to go to the summit and come back
down the needles of the Goute before night; I therefore decided to
retrace my steps. (P. 306.)
August 16, he once more began the ascent, this time starting
from Chamounix. The travellers, accompanied by twelve guides,
passed the night at the Grands-Mulets. In spite of his guides, who
were alarmed by the poor condition of the newly' fallen snow,
Hamel wished to go on the next day; at half -past eight in the
morning, they were on the last large plateau:
No one was ill. And yet for some time we had been feeling the
effect of the rarity of the air; my pulse rate was 128 per minute,
and I was thirsty all the time. Our guides suggested that we should
lunch .here, for higher up, they said, no one has any appetite ....
Each of us ate his half-chicken with pleasure.123 ....
We had reached the elevation of 2,300 fathoms .... No one was
90 Historical
talking, for at this height even talking fatigues one, and the air
transmits the sound feebly. I was still the last, and I was taking about
twelve consecutive steps; then, leaning on my alpenstock, I stopped
to take fifteen inspirations. I found that in this way I could advance
without becoming exhausted. Wearing green glasses and with a
crape veil over my face, my eyes were fixed on my steps, which I
was counting, when suddenly I felt the snow give way under my
feet ....
The whole sheet of snow slid from under the travellers, and
three of the guides disappeared forever in an immense crevasse.
After this fatal experience, no one had ventured upon this
undertaking "dangerous as well as useless", when F. Clissold tried
again successfully, on August 18, 1822. In his first rather brief
account,124 he limits himself to saying that all the guides, except
one, were "more or less affected by the rarity of the air".
The detailed account which he published later 125 is much more
explicit; it even contains very unusual theoretical ideas which we
shall report in the proper place.
It is strange to have to state that this stranger who was making
his first trip to the Alps endured the decreased pressure better
than the guides, almost all of whom had already ascended to the
summit of Mont Blanc:
We were not far from the Grands Mulets (he says) when the man
who was fastened to my rope untied himself, being absolutely
exhausted. I then had myself tied between two others; shortly after-
wards, a second one stayed behind, and finally all, except Favret
(one of the six guides) and myself, had to stop from weariness and
a difficulty in breathing which they attributed to the rarity of the air;
a little rest soon revived them. At two o'clock, we reached the
Grand Plateau. Marie Coutet, who could hardly breathe (he had
already ascended Mont Blanc five times) was surprised at my fine
condition. (P. 146.)
They slept in a little excavation of the Rocher Rouge (4490
meters) and suffered greatly from the cold. The next day, at
dawn, they set out for the summit:
Favret and I were the only ones who were comfortable, especially
in breathing. As for the others, some were stretched out flat on the
snow, others paused standing up, bent forward with their heads
hanging, finding it easier to breathe in this position. For my part, I
have felt much more fatigue in other trips and on much less lofty
mountains than I felt in ascending Mont Blanc; it is true that I was
walking more quickly then. My pulse rate did rise from 100 to 150
per minute, but my circulation always quickens to this degree when
I climb a steep grade, so that all in all I experienced nothing particular
or new to me. (P. 149.)
Mountain Journeys 91
The account of the trip of Dr. Clark and Captain Sherwill 1J"
contains very interesting details. They ascended Mont Blanc
August 25, 1825; leaving Chamounix at seven o'clock in the morn-
ing, they reached the summit the next day at five minutes past
three:
When they reached the Grand-Plateau, M. Clark was exhausted,
Captain Sherwill was greatly nauseated and oppressed .... Simon,
one of the guides, complained of headache ....
On the summit of Mont Blanc, M. Clark found breathing difficult,
even when he refrained entirely from moving. He felt in his chest a
sensation like that which precedes hemoptysia, a disease to which he
was quite subject in his youth. However he did not spit blood on the
summit of Mont Blanc. One of the guides who had accidentally
received a blow on the nose lost a little blood, which seemed darker
in color than usual. Both M. Clark and Captain Sherwill suffered
from violent headache; their faces were pale and drawn. The captain
spoke of a singular sensation which he had felt near the summit:
it seemed to him as if his body had an extraordinary elasticity and
lightness, as if his feet hardly touched the ground. The guides were,
in general, very tired and complained of headache.
In 1827, July 24, another ascent by Hawes and Fellowes,1-7
accompanied by ten guides. The night was passed at the Grands-
Mulets (—5°).
During the ascent of the Dome du Goute, they began to feel the
effects of the great elevation, the headache increased as they
advanced; the veins swelled, the pulse was strong and rapid ....
At a thousand feet from the summit, the travellers had nose-bleed,
and nearly every one spat blood; these symptoms were extraordinarily
severe in M. Felowes, who was very delicate; but M. Hawes, short,
sturdy, and robust, resisted better. Their breathing was strangely
affected; they could not take more than six or eight steps without
stopping. Two guides, completely worn out, were sick and vomited
much blood. Moreover, every one had the skin of his face cracked
and lost blood within. The cold was intense ....
By resting, though for only a short time, the travellers reached
the crest of Mont Blanc at 2:20. (P. 267.)
The same year, a Scotch traveller, Auldjo, made the same
ascent on August 9. Not having been able to get the original
account which he published, I am borrowing a summary of it
from the work of M. Lepileur, whom I shall mention again soon:
M. Auldjo says that he did not begin to feel the effects of the
rarefaction of the air until he had reached an elevation of about
4,200 meters; he was then attacked by oppression and difficulty in
breathing. His pulse became frequent; he felt thirst and a fullness
of the veins of his head, but no headache when he was quiet. Most
of his guides suffered in the same way and to the same degree. As
92 Historical
he mounted, he was more exhausted, the oppression increased, a
violent headache appeared, as did strong 'palpitations, general lassi-
tude, and a pain in the knee and the muscles of the thigh, which
made movement of the legs difficult. About the elevation of 4,570
meters, he had a strong desire to sleep, and was completely exhausted,
down-hearted, and discouraged; his guides had to force him to leave
the rocks of the Petits-Mulets. The rest of the ascent was extremely
painful for him; they had to hoist him by a rope along the last grade.
As soon as he had begun to feel ill effects, neither he nor his guides,
took more than fifteen or twenty consecutive steps. While climbing
the last hundred meters, the most robust and daring guide, he says,
was exhausted after three or four steps, and forced to stop to get his
breath. He suffered much from the cold on the side where the sun did
not strike. Finally, after climbing the last twenty meters with a little
less discomfort, he reached the crest, where he fell deeply asleep
immediately. He was awakened after a quarter of an hour; he was
better, the headache and the pain in the legs had stopped, but he was
shivering and thirsty;., his pulse was frequent, his breathing difficult,
although the oppression had lessened. He could not eat; the sight
and the smell of food nauseated him .... (P. 20.)
Mountain excursions became numerous; it was not only Mont
Blanc that the travellers, who had become "tourists", aimed at.
A German Swiss, Meyer,128 who published the account of his
excursions in 1812, gave his attention to physiological symptoms;
he found that they had been greatly exaggerated:
All that De Saussure reports on the effects of the atmosphere in
lofty elevations upon the animal organism has no general foundation;
there are still a great many things which are hypothetical. For
instance, at an absolute elevation of 10,000 to 12,000 feet and more
above sea level, not one of us was drowsy or in a feverish state, or
vomited or fainted, symptoms about which some travellers who
reached very lofty summits have said a great deal ....
Who could deny that when one is climbing, the pulse rate becomes
almost immediately twice as frequent as it was before? If one walks
then at a slow pace long enough to recover, the pulse will quickly
return to the same rate as on the plain or in the valleys .... I had
the opportunity to note that the fainting of one of our guides near the
summit of the Jungfrau had been brought on largely by the great
efforts he made in ascending, and partly also by the fear inspired in
him by the danger he was running. None of us felt anything of the
sort when we were descending. (P. 30.)
Let us note the fainting of the guide, whatever the expla-
nation given may be. Let us add that at lower elevations than those
reached by Meyer, Dr. Parrot, a celebrated mountaineer, expe-
rienced a strange symptom which he attributes, it is true, to the
heat, but in which the decrease of pressure seems to me to play
Mountain Journeys 93
an important part. He reports in the following words this symp-
tom which happened to him September 18: r2Q
I had been for two hours on the western edge of the glacier of
Lesa, at the height of 3436 meters; the heat was such that my eyes
began to grow red, and I felt a frontal headache with such drowsiness
and fatigue that I had great trouble in observing my barometer suit-
ably; I found no relief for this condition except in lying down on the
ground. (P. 386.)
The first ascent of Monte Rosa took place August 5, 1819; it
was made by two men who lived in the neighborhood, Vincent,
superintendent of the mines of Indren, and Delapierre, inspector
of forests, better known by the German translation of his name,
Zumstein.
In the first journey, no physiological disturbance was men-
tioned. But the second, which is reported with details in the
Memoires de l'Academie de Turin (vol. XXV, p. 230-252; 1820),
furnishes some interesting references. At first, in the night which
the mountaineers passed at the foot of the last ridges in the hut of
the Mineurs, which was occupied two months, "the highest in
Europe" (1681 fathoms), Zumstein "felt a certain oppression in
his chest which prevented him from closing his eyes all night.
"Perhaps," he added prudently, "this excitement was caused only
by the keen impatience for the morrow" (P. 237). When they
were near the summit, as the daring travellers were crossing a
dangerous ridge on steps cut in the ice, "the man who was second
in line grew pale and tottering leaned towards the slope at the
left (P. 241)"; rubbing him with snow restored him. On the sum-
mit, after a certain time for rest, the pulse rate of Vincent was 80,
that of Zumstein 101, that of one of the guides 104, and that of the
sportsman who was sick 77, which naturally surprised Zumstein.
At last they reached the top of the Vincent pyramid (4210
meters) :
They had little appetite, but a burning thirst. Vincent had already
felt discomfort while he was ascending, and Zumstein, as he stooped
to pick up some silvery butterflies which were lying half dead on the
snow, had an attack of dizziness, which fortunately soon disappeared.
(Anal, de Briquet, p. 16.)
On July 31, 1820, they repeated their ascent, in the company
of the engineer Molinatti, and passed the night almost at the very
summit of the mountain, at an elevation of 13,128 feet:
In the middle of the night, Zumstein was awakened by palpi-
tations which choked him; he got up to seek recovery and was soon
better.
94 Historical
The next morning, they continued to climb:
M. Molinatti, exhausted by the rarity of the air, was forced to stop
constantly, whereas MM. Vincent seemed to have wings, eager as they
were to reach the summit first; Zumstein, about fifty steps behind,
followed them panting, but soon overtook them.
Thus they reached the summit of Zumstein's Point (4560
meters) , and descended without trouble.
The other ascents of Zumstein, in 1821 and 1822, had no inci-
dents which would interest us.130
We note, therefore, in this ascent, evident physiological disturb-
ances, although less than those which the travellers to Mont Blanc
had reported.
Much less still are those observed by Hugi,131 who goes so far
as to deny even the acceleration of the pulse rate on lofty places,
which seems rather strange.
The greatest elevation reached by this traveller and his com-
panions was the Finsteraarhorn (4275 meters) :
At these elevations I never failed (he says) to observe the pulse
rate, the respiratory rate, and the temperature of the body. The results
were constant; that is, in these respects heights and planes show the
same results, when neither effort, nor fatigue, nor fear are involved.
I am omitting the table of observations. Wahren alone, who is noted
for his vigor all through the Oberland, felt a little nausea on the point
of the Finsteraarhorn. While he was working at the Pyramid, he
twice lost power of vision, so that he was forced to sit down. (P. 218.)
On the opposite side, Hipp. Cloquet KJ- states that the symptoms
of decompression are often felt, even at the low elevation of the
Grand Saint-Bernard:
The rarefaction of the air .... causes in the organs of respiration
an alteration strange enough to be mentioned. Persons with a strong
constitution and with lungs in perfect condition experience a certain
pleasure in breathing an air as cool as it is pure and light; on the
contrary, those who lack these advantages, and especially those who
are asthmatic, experience a marked distress and an extreme difficulty
in breathing, when they visit the monastery and its surroundings.
At the Saint-Bernard travellers have been seen to be asphyxiated, so
to speak, for want of air, and to fall in a faint, without any other
known cause, and this happens often to weak and delicate persons.
At the beginning of the syncope, the pulse rate is very high; but the
greater the strength of the lungs, the less is this acceleration in the
pulse rate.
It is also to the rarity of the air that we should perhaps attribute
a strange phenomenon presented by the observation of wounds in this
place. Their cicatrization requires double or even triple the time it
Mountain Journeys 95
would take on the plain for its entire completion .... The same thing
has been observed on all high mountains. (P. 33.)
The accounts of travellers on Mont Blanc are always most
characteristic in reference to mountain sickness. After Auldjo,
an interval of seven years had elapsed, during which only one
ascent (Wilbraham, August 3, 1830) had taken place. But Sep-
tember 17, 1834, Dr. Martin Barry133 made a scientific ascent the
account of which is very interesting.
He mentioned physiological disturbances only above the Grand
Plateau:
We had then reached an elevation at which I was to verify the
statements of previous travellers about the exhaustion brought on by
the slightest effort in a much rarefied atmosphere. I did not expe-
rence such discomforts before reaching this point, and I did not see
any in my guides. I could take only a small number of steps at a time,
and those were short and slow. Two or three deep inspirations were
enough at each step to revive me; but when I started again, the
exhaustion returned as before. I felt an indifference which was not
overcome by the sight of the summit so close at hand. I even had a
slight fainting fit, and was forced to sit down for a few minutes; but
a little wine revived me ....
After a few minutes rest at the summit, the weakness, exhaustion
and indifference disappeared .... (P. 112.)
The account of the ascent of Count de Tilly, which took place a
fortnight after that of Barry, contains so many mistakes and con-
fusions that we cannot give our time to it. But the following
year, an Englishman, Atkins,134 reached the summit with two com-
panions, Hedringen and Pedwel, without counting the guides, and
observed interesting data.
His ascent took place August 23, 1837. He begins by making
excuses as if for a foolish action. The first symptoms are not re-
ported by him until on the Grand-Plateau:
I was forced (he says) to stop every ten steps to get my breath
and rest my legs. I suffered from thirst and from deathly languor.
From time to time I swallowed a mouthful of vinegar, to moderate the
thirst which devoured my entrails, and I often had nosebleed.
Coutet was not free from distress and Jolliquet could not hold
his head straight. Some of those who were ahead dragged themselves
this way and that, others raised themselves, then fell down again. At
the foot of the wall of La Cote lay a man stretched out at full length
and motionless. I cannot say whether this was one of the guides, but
he finally rejoined us ... .
At last, after a terrible ascent, after having been forced to stop
every two minutes to breathe, we reached the summit .... It was 7°
below zero (P. 36.) ....
96 Historical
The little dog which accompanied us had to struggle against sleep
as soon as we had passed the Grand-Plateau, and every time we
stopped, it tried to lie down at our feet, finding the snow cold. It
showed more than one sign of surprise, often casting wild eyes around
it. Sometimes it made an effort to run very fast, and sometimes fell
down exhausted. As for its appetite, the chicken bones we gave it
disappeared with astonishing speed, but it did not appear to suffer
from thirst ....
Hedringer, wishing to have the glory of being the first to set foot
on the crest, began to run, but he had hardly taken a few steps, when
from exhaustion he stretched himself out stiffly on the snow for two
or three minutes, enduring cruel pains. He felt the consequences of
his mistaken ardor as long as we remained on the summit (P. 56) ...
Our breathing became more and more free as we descended, and
we felt so light that we hardly seemed to touch the ground (P. 59).
After that time, the ascents of Mont Blanc became more numer-
ous. From that of Atkins to the celebrated expedition of Bravais,
Lepileur and Martins, in 1844, there were 17; but I can hardly call
any of them interesting except that of Mile. d'Angeville (Septem-
ber 4, 1838), who had to be almost carried to the summit.
Dr. Rey 1&~ in the following words reports the symptoms felt
by this daring woman:
I learned from Mile. Dangeville that in her usual condition her
pulse beats 58 to 60 times per minute, very soft and very regular.
When she left Chamounix for the ascent, it was already 64 and
increasing, emotion was beginning: at the Grands-Mulets, it was 70
and irregular, although she felt better, mentally and physically. On
the grade which is above the Grand-Plateau, where she began to feel
a little tired and sleepy, she counted 136 beats at unequal intervals,
that is, much more than double the number in her ordinary condition.
When she had reached a place called the Mur de la Cote, near the last
crest, she felt a sort of agony, caused by an excessive need for sleep,
and she cannot tell how high this extraordinary acceleration rose
during her severe attack, but five minutes after she reached the
summit, the pulse of the noble and intrepid French woman had already
dropped to 108 (p. 341).
Now let us consider the other mountains.
The celebrated naturalist Desor,130 in the report of numerous
excursions with a prolonged stay in lofty places which he made in
the company of the illustrious Agassiz, is surprised at feeling
and observing no physiological disturbance; he is especially struck
by it at the time of his ascent of the Jungfrau (4170 meters) in
1841:
I must confess that while we were on the summit, and also during
the ascent, we experienced none of those symptoms, such as nausea,
nosebleed, buzzing in the ears, acceleration of the pulse, and many
Mountain Journeys 97
other discomforts, to which most of those who have made the ascent
of Mont Blanc say that they were prey. Should we attribute it to the
difference of 500 meters between the height of Mont Blanc and that
of the Jungfrau? Or should we seek the cause of it in the habit we
had formed during several weeks of living at an elevation of more
than 2,590 meters? But we should note that M. Duchatelier, who had
been in the mountains only a few days, was not ill either. Without
claiming to decide this question, which belongs more particularly to
the realm of physiology, I am, however, inclined to think that there is
a little exaggeration in all that has been told us on this subject. Per-
haps also a few travellers have been deceived by their imaginations,
like the students of medicine who every day think themselves attacked
by the disease the symptoms of which the professor has just set forth
to them. Some German physiologists, if I am not mistaken, even claim
to have observed the most extraordinary symptoms on mountains only
' a few thousand feet high. (P. 409).
He refers again 137 to this immunity in reference to his ascent
of the Schreckhorn, or rather the Lauteraarhorn (4030 meters),
August 8, 1842:
I should note that no one of us experienced the least discomfort
either on the summit, or on the ascent, or on the descent, so that in
this respect I can fully confirm what I said elsewhere about the so-
called ill effects of lofty regions.
And yet to this absolute conclusion we can oppose the follow-
ing fact from Desor's 138 own accounts:
We had been travelling thus for a quarter of an hour when
suddenly our friend Nicolet shouted to us that he could do no more.
He experienced that complete fatigue by which one is attacked some-
times in the lofty Alps, but which passes very quickly if one rests a
moment .... "I feel sure," he said, "that I shall never reach Zermatt
alive" .... (P. 342.)
The travellers were only at the foot of Mont Cervin.
Gottlieb Studer139 ascended the Jungfrau August 13, 1842; he
felt no discomfort either and gives a strange reason for it:
We perceived none of the symptoms which at such great heights
travellers have often attributed to the rarefaction of the air; yet we
must note that in such a long ascent, for three long hours, the chest
can rest .... (P. 313).
On the opposite extreme, another tourist, Spitaler,140 who with
several companions made unimportant ascents, certainly exag-
gerated the sufferings experienced. So, in regard to the "Venetian"
on Pinzgau, a mountain of 3675 meters, he makes the following
lamentable picture:
98 Historical
We needed to breathe more frequently and all our muscles acted
painfully; the heart beats and the pulse doubled or even tripled; the
pulse was soft and weak, difficulty in breathing amounted to anguish,
and stopped one of us a few hundred steps from the summit; another,
returning, had a slight pulmonary hemorrhage; the secretion Of the
kidneys was strangely lessened .... no one was troubled by perspi-
ration, but thirst was very great. The temperature was -f- 2° to +6°
R . . . — On the plain we should not have been cold, but at an elevation
of 9,000 feet a painful sensation of cold seized us; our skin was flabby,
our faces aged; the strength of the muscles was greatly lessened, and
out of forty, only twenty-six reached the summit.
The evidence of the celebrated English physicist, Principal
Forbes, is much more valuable and much more exact. Forbes 141
speaks of the symptoms of mountain sickness in reference to his
expedition to the col du Geant (3360 meters), April 23, 1842, on
which he noted that one of his guides was slightly affected:
We were about a thousand feet from the summit, when Couttet felt
his respiration a little affected, but not severely. That is a very
common symptom, which depends greatly on the state of the health.
I hardly felt it from here to the summit. But in 1841, I was definitely
affected at a lower level, when ascending the Jungfrau. The guides
say that these variations depend upon the state of the air; and David
Couttet assured me that on different days, he and his father had at
the same time felt difficulty in breathing at a very moderate height.
(P. 224).
After all these travellers, naturalists or mere tourists, who
spoke only incidentally of physiological symptoms, we come to a
scientific expedition which has justly remained famous, the first
on Mont Blanc since De Saussure, one of the members of which,
Dr. Lepileur, was especially charged to observe himself and his
companions from the physiological point of view. And so the
report 1 4- which he makes of this ascent deserves to be analyzed
here at considerable length.
But before beginning the report itself, M. Lepileur, who was a
frequenter of mountains, says that in his excursions previous to
the ascent of Mont Blanc, he experienced or observed a certain
number of interesting phenomena, particularly because of the
moderate heights at. which they appeared:
While I was going from Martigny to the Grand Saint-Bernard, in
September 1832, I saw my brother and two of my friends display most
of the symptoms of mountain sickness; one of them, a young man
twenty-six years old, was seized by general discomfort, fatigue,
breathlessness, and palpitations, one hour before reaching the monas-
tery, and soon he could not walk without being supported and without
making frequent halts at equal intervals. When he reached the
Mountain Journeys 99
monastery, he went to bed, without being able to take anything but
a little tea; he suffered all night from a discomfort which he compared
to that of fever; the next morning he still felt oppression, and has-
tened to descend to Martigny. Of the two others, one was thirty years
old, and my brother seventeen: they had very little discomfort during
the last half -hour of the ascent; but although they were not very
tired when they arrived, they had not the slightest appetite, and even
the sight and the smell of food disgusted them. During the night they
recovered completely; on the next day, they were able to ascend to
one of the crests to the south of the monastery, and to go back down
to Martigny on foot. The fatigue of this day's efforts also took away
their appetite that evening, as it did that of another of our companions,
who had felt no effects at the Saint-Bernard; but then it was only
fatigue, there was no trace of the discomfort which they had felt the
night before.
In the month of June, 1835, while I was climbing the slope of
snow which extends below Chateau Pictet on Buet, at a height of
about 3,000 meters, I felt my strength fail, it was very hard for me to
go on. One of my friends who accompanied me had already been
suffering for nearly a half-hour from fatigue in the legs and knees.
He made frequent halts. As for me, I could not take more than 160
consecutive steps.
A little chocolate which I ate restored me almost completely;
however I was still obliged to stop from time to time, although I was
much less exhausted. From Chateau Pictet to the crest of Buet the
slope is very gentle, and I felt no lassitude while mounting it.
In the month of July of the same year, I was climbing with a
guide on the point of rock which towers above the Saint-Theodule
pass on the north; about sixty meters below the crest, I perceived
that the guide stopped frequently; soon it was impossible for him' to
take more than eight to ten steps without stopping for breath. He
was a robust man and in the prime of life, so that I could not believe
that the weight of my sack which he was carrying was enough to
weary him to this extent; seeing him pant, turn pale, and nearly fall
in a faint, I told him to take a little rest; he would not admit his
distress at first, but finally was compelled to sit down, a cold sweat
ran down his face, he was exhausted. I had him eat a little bread
and chocolate, which, with a ten minute rest, quite restored him. The
elevation at which we were was hardly one hundred and fifty meters
above the Saint-Theodule pass, that is, 3,560 meters, but I had noted
when we left Zermatt about midnight that the guide was drunk,^ and
that is what had made him so susceptible to the rarefaction of the
air.
Two days after, while climbing the Breithorn, at the east-south-
east of the Saint-Theodule pass, one of my guides found it impos-
sible to climb higher than the last plateau (about 3,900 meters) ; this
man was sixty years old and was afflicted by a double inguinal
hernia. Another guide of the same age panted greatly while climbing
the terminal cone of the Breithorn (4,100 meters), the grade of which
is very steep. The other two guides, men of thirty to thirty-five years,
felt no more distress than I. The next year, making the same excur-
100 Historical
sion with one of my friends, I was suddenly seized by unconquerable
sleepiness as I was crossing the vast plateau south of the Breithorn,
where a guide had had to stop the year before. I was sleeping as I
walked, no matter what efforts I made to stay awake; one of the two
guides had the same experience, the other and my travelling com-
panion felt nothing of the sort. As we returned to the Saint-Theodule
pass (3,410 meters), after a light meal taken with good appetite, we
all slept in the sunshine for about an hour. When he awoke, my
travelling companion was nauseated and vomited what he had eaten
an hour before. I must note that the second night before, we had
slept little and badly, and that after a walk of eight hours, we had
had only three quarters of an hour of sleep on the night before our
excursion. Several times, in Paris, I have found myself thus over-
powered by sleep so that I slept and even dreamed while I was
walking. Moreover, none of us felt any other discomfort during this
excursion.
In July, 1844, while climbing the slope of the Couvercle, at an
elevation of about 2,500 meters, I felt a distress and a difficulty in
climbing like that I had experienced in 1835 on Buet. This condition
lasted about twenty minutes. I was not forced to stop, but I suffered,
and my strength seemed much lessened; at last, without any percep-
tible cause, for I continued to ascend, the discomfort suddenly ceased,
I could climb without trouble the height of about 150 meters, which
separated the point where I was from the Jardin. When I reached the
Jardin, I ate with considerable satisfaction; but I was soon satisfied. Dr.
Noel de Mussy, one of my companions on this walk, who was in the
mountains for the first time, was only a little out of breath; at the
Jardin, he ate with a good appetite. And yet, in the evening, while we
were returning, he was much more tired than I. Another traveller
who accompanied us felt no distress.
Finally, in the month of September, M. Camille Bravais, who
ascended with me to the rock of the Echelle, when we had reached
an elevation of about 2,300 meters, had to stop every twenty steps
to get his breath. It is true that M. C. Bravais, affected no doubt by a
slight hypertrophy of the heart, was never able to climb a steep
grade without experiencing severe palpitations. (P. 33 et seq. of
the separate printing.)
Now let us turn to the ascents of Mont Blanc. In the first
attempt with MM. Bravais and Martins, July 30, 1844, they exper-
ienced some effects on the Grand-Plateau (3911 meters), where
they set up their tents for the night, and beyond which they could
not go: distaste for food, diarrhea, prostration. M. Lepileur was
seized by violent shivering, recurring eight or ten times an hour;
M. Martins had a similar attack. They had helped their guides in
setting up their tent, and had become much fatigued.
August 7, all three set out again, and camped at the Grand-
Plateau: the shivering attacked M. Lepileur there again; M.
Martins was quite ill, Bravais felt nothing but an irresistible desire
Mountain Journeys 101
to sleep at the Grandes-Montt-es (3800 meters). The face of one
of the guides was cyanosed, which M. Lepileur attributes to the
cold. On the descent, M. Martins had a slight hematuria.
August 28, third journey; departure from Chamounix at mid-
night:
The ascent went very well up to about 3,100 meters. There,
Tournier felt ill, lost courage entirely and was forced to descend.
He was pale, his face was bathed with sweat, and he could hardly
climb even a few steps, although his burden had been taken from him
and although we were on a rather gentle slope. He attributed this
failure of his strength to the fact that the day before, not expecting
to make the ascent, he had worn himself out at a painful task. His
distress ceased as soon as he was two or three hundred meters lower.
At 3,600 meters, I felt no ill effects as long as I walked slowly;
but when I wanted to ascend quickly, as for example, to rejoin my
travelling companions, after having paused a moment, I felt discom-
fort. M. Bravais suffered much from cold feet for several hours.
Several times he had been obliged to stop, and we had reestablished
circulation in him by slapping the dorsal side of his toes with our
hands ....
At the Petit-Plateau, I ate, at first with repugnance, then with
pleasure, when a little food had stimulated the stomach. We all
took a little wine; that was always what helped us most ....
M. Bravais again, this time like the two others, became very sleepy
about the elevation of the Petit-Plateau (3,800 meters).
When we reached the Grand-Plateau, he was a little tired and
so was I. M. Martins was not. Cachat and Ambroise Couttet were
exhausted. As soon as they had halted, they lay down on the snow
in the sunshine, and remained there for three or four hours, without
being able to help us at all. Ambroise Couttet felt nausea besides
all afternoon. As soon as he tried to stand up, he was threatened
with syncope. The others helped us set up the observation instruments
and clear our tent which the snow had three quarters buried on the
north-east side. This labor did not tire us at all, and we were no
more out of breath than the first time at Chamounix, when we had
set up the tent ourselves for practice and to show the guides how it
ought to be done.
None of us had as much appetite as in the valley. M. Bravais had
very little; M. Martins and I had none at all. However, I felt no
distaste for the fresh food which we had brought. Three hours after
our arrival, when I took off my crape mask which hindered me in
making my observations, I felt , the beginning of a headache which
stopped as soon as I put my mask back on. When I gave careful
attention to the observation of some instrument, when, for example,
I read a thermometer placed on the snow, and in general whenever
I was in a position in which respiration was hampered, I felt a slight
sensation of nausea which lasted hardly one or two seconds; the
instant before and the instant after, I had no discomfort at all. MM.
Martins and Bravais noticed the same effect in themselves. With that
102 Historical
exception, we were very well, gay, and full of confidence. We noted
this slight discomfort only to be rigorously exact.
A. Simon almost fainted while I was feeling his pulse. He was
standing, and just had time to lie down on the snow to avoid a
complete loss of consciousness. After our arrival, he had been busy
clearing the tent and setting out our camping equipment without
feeling any discomfort; however, this time he was not quite as well
as the others. After some time he recovered and even ate with
appetite. In the evening, everyone was well; our two invalids had
recovered from their fatigue; I slept at night, although very uncom-
fortable because I could not stretch out my legs. I also felt some
rheumatic pains in my right knee, toward the inner edge of the knee-
cap, and a little neuralgia on the outer side of the left thigh. M.
Bravais made observations until midnight. August 29, at four o'clock
in the morning, I made the first observation. I was rested and felt
quite strong, but I had no appetite; the only food I cared to eat was a
few raisins; the provisions, which had been thoroughly frozen for a
month, and especially the meat, filled me with disgust. About six
o'clock, M. Bravais and I took a little bread and wine. The first hours
of the morning were passed in making observations and a few experi-
ments, during which we were standing, coming and going on the soft
snow. At ten minutes past ten, we started for the summit.
The crossing of the Grand-Plateau was painful because of the
snow into which we sank up to the calf. I did not feel as strong as
in the morning, but I felt no distress. I perspired abundantly while
crossing the Grand-Plateau and during the first half-hour of the
ascent. Our hands and feet were very cold, those of M. Bravais
particularly. M. Martins lost his breath a little more and a little
more quickly than we did. Up to the foot of the upper Rochers
Rouges, about 4,400 meters, I had no discomfort of any sort; we took
350 or 400 steps consecutively without stopping for breath; but when
we reached this number, we felt the need of resting for a few
moments. The grade which we were climbing, measured with a
geologist's compass, was, at the elevation of 4,300 meters, 42°, and
the slope of our course was 16°.
About 4,400 meters, I began to feel after ten or twelve steps a
little fatigue with pain like that of lumbago in the legs and knees. I
counted my steps again, we were still taking one hundred between
halts; but the last twenty were very painful to me. This pain in the
legs stopped as soon as I halted, and the first steps I took after that
were very easy. I began to be very anxious that the grade should
become easier. A quarter of an hour before we reached the top of
the upper Rochers Rouges it did become less steep. About this height
(4,500 meters) I perspired a little, but it lasted only a few moments.
After a short pause, we continued the ascent; a little before the top
of the upper Rochers Rouges, I had begun to feel an undefinable
discomfort when I was walking; I had neither headache nor palpi-
tations, once or twice I felt a few throbs in the carotids, no doubt
because I had made a few steps more quickly than the others. I was
not nauseated either, but I felt a general discomfort, a sort of exhaus-
tion. I was weak and it seemed to me that I had just enough strength
Mountain Journeys 103
to carry out the motions of locomotion for a certain time and then
it would be all over; in a word, I was like a man who, at the end of
a long day of walking, perfectly exhausted, feels that he can reach a
point not very far away, but that he must give up going any further.
I could walk only with my head lowered and my chin nearly touching
the sternum. This was the attitude of us all, and when we were
getting our breath, it was also with the neck stretched out and the
body leaning forward during the first seconds. Clissold had observed
the same thing. I felt a slight desire to sleep several times and yawned
occasionally. What added greatly to the discomfort was a rather keen
thirst or rather a dryness and a sticky condition of the mouth; a little
snow melted on the tongue while I chewed a raisin quenched the
thirst for a few moments. This uncomfortable condition developed
gradually, and it was quite endurable when at about 4,560 meters a
violent wind from the northwest struck us. At once we felt as if our
hands, our faces, and the part of our heads which the head covering
did not protect were freezing. The side of the body which the wind
blew upon was also very cold, especially in MM. Bravais and Martins,
whose clothing was rather thin. As we were climbing in a zigzag,
when we had the wind in our faces during a squall, I experienced
then in the highest degree the sensation which I described in connec-
tion with our first ascent to the Grand-Plateau. It was in vain that
I covered my nose and my mouth with my hand, stooped, turned aside
my head; I could not breathe any more than if I had been under
water. I felt the distress of asphyxia, my head whirled, and I felt
slightly nauseated. When I turned my back to the squall, it seemed
as if the wind made a vacuum around me, and I had difficulty in
breathing. I was the only one to feel this effect of the wind, both on
the first and on the third trip. This increase of discomfort lasted without
stopping for a quarter of an hour or twenty minutes, I asked myself
whether I could reach the summit, I felt sure that I should succeed;
but I had to use all the mental strength I possessed to actuate my
physical powers. Sometimes too I advanced mechanically, without
thinking, so to speak. No one talked, everyone, like me, had but one
thought, that of advancing a few steps more. So the distance one tra-
verses between the Rochers Rouges and the summit, although it took
us nearly two hours to cover it, did not leave many details in my
memory, and returns to me as a vague recollection, rather painful
and very short, no doubt because of its uniformity. The same thing
was true for MM. Bravais and Martins, for we were all three surprised
when we had to admit from our notes that it took us nearly two hours
to go from the Rochers Rouges to the summit. We remembered only
two or three incidents of this ascent, which, although painful, was
however made without interruption and without the excessive fatigue
and exhaustion experienced by some travellers. It is, I think, to the
blank left in the memory by this part of the ascent to Mont Blanc
that we should attribute the mistakes and the confusions so frequent
in the accounts of travellers when they speak of this passage.
When we halted, after two or three seconds I was in perfect
condition; I felt no discomfort except a slight thirst and cold feet
and hands. We did not find, as De Saussure observed in himself, that
104 Historical
the distress caused by walking reached its highest point after the
first eight or ten seconds of the halt.
During the last quarter hour of the ascent, the slope was gentler
and the wind blew less violently. These two causes, added to the joy
I felt when I saw the summit only a short distance away, lessened
my distress greatly. M. Bravais suffered only from the cold. We had
already realized that of the three of us it was he who felt the effects
of the rarified air least. M. Martins was the one who suffered most
from it. He was very much out of breath, had palpitations, throbbing
in the carotids, and a little headache; he felt a general fatigue, and
took fewer steps than we did. When he reached the summit, he
thought he was still a half hour away from it, and felt keen joy when
he found he was there. None of us felt pain or fatigue or anything
extraordinary in the coxofemoral articulation while we were walking;
in general, we felt no fatigue in the muscles of the thigh. MM.
Bravais and Martins had a little in the right anterior muscle only.
Between the Rochei's Rouges (4,500 meters) and the Petits-
Mulets (4,660 meters), we first took eighty steps without stopping
for breath, then this number was lessened to seventy, and finally to
thirty-five or forty steps between the PetTts-Mulets and the summit.
However, as we came near the highest point, since the grade was very
moderate, we made one or two stretches longer than the others. At
about forty meters from the summit, M. Bravais wanted to see how
many steps he could take climbing as quickly as possible and in the
direction of the great slope. He had to stop after thirty-two steps;
he felt, he said, that when he stopped, he could have taken two or
three more, perhaps four, but that it would have been quite impos-
sible for him to go beyond that.
During the ascent, none of the guides or porters seemed affected;
two of them were a little more fatigued than the others; they were
Frasserand, who the day before had been rather fatigued when we
reached the Grand-Plateau, and A. Couttet, who had been ill there
all afternoon. Our two guides and the porter Simon seemed able to
take more steps than we were. Several times they stopped only
because they were asked to. M. Bravais and I reached the summit at
the same time; M. Martins joined us there a few minutes afterwards . .
For eight or ten minutes I had keen pain in my feet, caused by
the change from intense cold to warmth. I was also rather drowsy
shortly after we arrived and when the pain in my feet had stopped.
I lay down on the snow where I remained five minutes, but without
being able to sleep. Then I got up, the desire for sleep disappeared,
and during the whole time we spent on the summit I felt absolutely
no painful sensation, except a little cold the last hour. I had no
appetite, although the idea of eating caused me no disgust. M.
Bravais was also very well; only from time to time he felt the slight
nausea which M. Martins and I had observed in ourselves the day
before on the Grand-Plateau. He had an appetite and ate some
biscuits and a few prunes. Shortly after our arrival at the summit,
he and I each drank about a third of a glass of brandy. This liquor
seemed to us delicious and very mild, to our great surprise; it did us
much good, and gave us strength without causing the excitation
Mountain Journeys 105
usually produced by alcohol. We also drank a little wine, during the
first two hours of our stay on the summit. A moment after he reached
the crest, M. Martins was attacked by nausea, and vomited some seeds
of raisins which he had eaten an hour before. Vomiting relieved him.
He compared his illness to seasickness. When he lay down, he had
no trouble, but moving about and standing brought back the nausea.
An hour afterwards, he was better; after two hours, the sickness was
completely gone. He drank a little wine, but did not wish to eat. The
six men we had with us ate hardly anything, but they drank about
two bottles of wine and half a bottle of brandy. All were in perfect
health; only two were evidently fatigued, although they would not
admit it ... .
We could walk without any difficulty on an almost horizontal
plane; but as soon as we had to climb, we were affected by panting
and general lassitude ....
There was a white coating on the tongues of all of us, but less
in the guides than in us, and their appetites were not, like ou^s,
completely or almost completely wanting. (P. 44-54.)
After a few hours of observations, they descended to the Grand-
Plateau; M. Martins was attacked by panting, palpitations, and
throbbing in the carotids, so that he had to sit down. During the
night, M. Lepileur felt violent sciatic neuralgia on the left side.
His appetite did not return until the next day when he reached
the altitude of 3000 meters while returning to Chamounix; during
the whole day, he had eaten only a small piece of bread dipped
in a little wine. He sent fresh provisions to Martins and Bravais,
who had remained on the Grand-Plateau; they received them with
great pleasure and made a good meal; however, what five of them
ate would hardly have equalled the ration of one man in the
valley.
The urine of all of them was scanty and dark.
The work of M. Lepileur is finished by a series of tables indi-
cating the pulse rate of himself, Martins, and three guides from
Servoz or Chamounix to the summit of Mont Blanc. He summar-
izes it as follows:
The increase of the pulse rate is a constant result, when one is
ascending, beginning with a certain elevation, .... which may vary
with the individual .... My pulse was less frequent at Chamounix
(60) than at Paris (67.25) ; . . . . the contrary was true of M. Martins
.... The ratio of frequency between Chamounix and the summit is:
for M. Martins 0.82; for me 0.68; for Muguier 0.67; for Couttet 0.60;
for Simond 0.61. (P. 77-80.)
M. Martins143 much later narrated the same journey; his recol-
lections agree with those of M. Lepileur:
On the Grand-Plateau the guides began to clear snow off the tent.
106 Historical
This work was painful; each of them had hardly removed a few
shovelfuls when he stopped to breathe; a hidden distress was revealed
on every face; appetites were gone. Auguste Simon, the tallest, the
strongest, the most daring of the guides, collapsed upon the snow,
and almost fainted while Dr. Lepileur was feeling his pulse; it was
the effect of the rarefaction of the air added to fatigue and insomnia,
from which all of us suffered more or less. We were then about 4000
meters above sea level, and there are few men who are not inconven-
ienced at 3000 meters. I am not surprised that in this ascent we felt
the effects of the rarefaction of the air, which we had hardly noticed
in the two previous ascents. Never had we mounted so quickly from
Chamounix to the Grand-Plateau; starting from 1040 meters above sea
level, after ten and a half hours of walking we were at an elevation
of 3930 meters; that is a difference in level of 2890 meters, traversed
in less than a half day. All discomfort disappeared when we ceased
moving. (P. 25 of the separate printing.)
The next day, they finished the ascent:
The rarefaction of the air ... . compelled us to walk slowly;
every twenty steps we stopped breathless ....
We were reaching the goal, but we were walking slowly, our
heads lowered, our chests heaving, like a procession of invalids. The
effect of the rarefaction of the air was felt painfully: the column
paused constantly. Bravais wishes to find out how long he could
continue climbing as quickly as possible; he stopped at the thirty-
second step without being able to take one more. At last at a quarter
of two we reached the long desired summit. (P. 27.)
The account of the ascent of July 19, 1859, made by MM.
Chomel144 and Crozet, has also given us interesting observations;
they followed a route different from the usual one, from the beaten
path, we may say, so frequent have journeys to Mont Blanc
become:
There comes at last the cap of Mont Blanc, which, in spite of its
slight elevation above the Mer de Glace, nevertheless requires two
more tedious hours of ascent. During this last stretch, the lack of air
makes every movement of the body painful, and one must make
superhuman efforts to resist palpitations, sleep, and fainting ....
Only a few feet now separate us from this long-desired summit.
Our self-respect spurs us on, and rising from the snow on which we
were stretched, we cover the rest of the way at a run ....
And here we are on the summit of the giant of the Alps. The
first impression .... was, alas! a dizziness and contractions of the
stomach which made us reel.
The celebrated English physicist Tyndall145 is one of the most
ardent mountaineers in the Alps. Every year sees him planting
his alpenstock on some new summit. And it is not only with a
scientific purpose that he runs thus the greatest dangers; it is not
Mountain Journeys 107
only the great spectacles of nature which attract him and thrill
him; he too seems gripped by this passion for climbing for the sake
of climbing, which, though it had its origin in England, is making
progress today in our own country. But his evidence has all the
more value for these different reasons.
August 12, 1857, Tyndall made his first ascent of Mont Blanc,
in the company of MM. Hirst and Huxley. The latter had to stop
at the Grands-Mulets.
When he reached the Derniers Rochers, Tyndall felt exhausted.
The guide Simond cried at every halt: "Oh, how my knees hurt!"
I lay down upon a bed composed of granite and snow, and went
to sleep immediately.
But my companion soon awakened me: "You frightened me," he
said, "I have been listening for several minutes, and I have not heard
you breathe once."
We got up then, it was half past two .... To the feeling of fatigue
we had felt till then was added a new phenomenon, palpitations. We
were constantly subject to them, and sometimes they became so severe
as to cause some apprehension. I counted the number of steps that I
could take without stopping and found it to be fifteen or twenty. At
each halt my heart beat hard enough to be heard as I was leaning on
my alpenstock, and its subsiding was the signal for a new advance.
My breath was short, but easy and unhampered. I tried to find out
whether the articulation of the thigh was relaxed because of the
decreased pressure, but I could not be sure ....
After we had passed the Derniers Rochers, we struggled on with
the stoical indifference of men who are carrying out a duty without
bothering about the results. At last a ray of hope began to brighten
our spirits; the summit was visible, Simond showed more energy ....
at half past three I clasped hands over the summit. (P. 80.)
The account of the second ascent, made September 12, 1858,
merely alludes briefly to the fatigues of the mountains, (p. 189.)
In 1859, an ascent still more important and very profitable for
science. Tyndall, Frankland, and nine guides passed a night on the
summit of Mont Blanc; they stayed there about twenty hours:14"'
We did not suffer from the cold, although we had no fire and the
snow was at a temperature of — 15°C. But we were all ill. I was sick
when I left Chamounix .... I had frequently conquered my discom-
fort on previous occasions, and I hoped for the same thing this time.
But I was absolutely disappointed; my illness was more deeply rooted
than usual, and it grew worse during the whole ascent. But the next
morning I was stronger, whereas the opposite was true for several
of my companions. (P. 54.)
The same year, a German, Dr. Pitschner,147 made a remarkable
ascent of this same mountain; he was very seriously affected:
108 Historical
At six o'clock in the morning, we were in the Corridor (3,990
meters) ; the thermometer marked — 8°C. We had hardly been there
five minutes when a strong desire to sleep seized us, and conquered
me completely. My respiration was very painful; my eyes blinked,
I had buzzings in my ears, headache, nausea; soon I vomited repeat-
edly; Balmat was as much affected as I, and his desire to sleep was
so great that he lay down on the snow, and I immediately let myself
fall beside him.
"I cannot go any further without sleeping a half-hour", I said to
Balmat .... I fell into a lethargic sleep, interrupted by smothering
spells, which finally seemed dangerous to Balmat; and so he began to
stir me and shake me, without being able to awaken me. Fifteen
minutes passed. His shouts awoke me, and he said to me: "You cannot
stay here any longer, you must go on". Perspiration covered my face;
I rubbed my face with snow, and after a score of deep breaths, I felt
better ....
From my sensations on the glacier, it is evident that the effect of
mountain air was evidenced in me very definitely; it produces dang-
erous congestions ....
On our return, at three o'clock in the afternoon, the same
symptoms appeared in the same place, but with much less intensity:
headache, nausea, vomiting.
The expedition of Dr. Piachaud,14S July 26, 1864, gave results
just as interesting. The author gave heed to the physiological
phenomena experienced by his companions and himself, and "attri-
buted to the rarity of the air":
The chief symptom (he says) is the oppression, which hardly
exists when one is resting, but which appears as soon as one starts
walking, then stops again when one halts. From it there results the
necessity of increasing the number of inspirations, and thence such a
fatigue that one is forced to halt every twenty or twenty-five steps.
This fatigue, moreover, is not like that one feels as the result of a
long walk; it is not the legs which are chiefly affected; it takes
possession of the whole system; there is a sort of general depression
both mental and physical. I should add that this peculiar condition is
observed only during the ascent, for once I had reached the summit
and during the descent, I felt nothing of the sort. Another noteworthy
effect of the rarity of the air is sleepiness, which I could hardly
resist; I felt that if I had stretched out on the snow, or if I had been
alone, I should have gone to sleep immediately. I do not think that
this drowsiness can be attributed to the cold, for on the summit, where
the cold was very keen, I was wide awake.
I also experienced very slight vertigo, but I mention it only to
omit nothing. As for nausea, vomiting, fainting, hemorrhages, none of
us was affected by any of them; our guides, of whom I asked infor-
mation on these different points, told me that they had never observed
hemorrhages. As to oppression, which is the symptom most frequently
observed, I should say that it is far from being absolute, for of the
six of us, I am the only one who felt it very definitely; the guides
104 ___.
104
108 ___.
104
108 ___.
104
96 ___.
96
92
80
Mountain Journeys 109
did not complain of it and M. Loppe could run when he got near
the summit. (P. 86.)
Examination of the pulse rate gave the following results:
Chamounix Grands-Mulets Mont Blanc
1000 meters 3000 meters 4800 meters
Carrier, guide 116
Couttet, guide 96
Tournier, guide 96
Payot, guide 92
Loppe, traveller 88
I now come to the two ascents of Mont Blanc which were note-
worthy from the standpoint that interests us because for the first
time the whole combination of physiological phenomena was
studied with the precision instruments used in laboratories. Dis-
turbances of circulation and respiration were thus determined in
the conditions which the present exactness of physiological re-
search demands. Besides, these observations serve as a basis for
an entirely new theory of mountain sickness, which will be
discussed in its proper place.
M. Lortet149 begins with a rapid historical survey of the symp-
toms felt by the most celebrated travellers. Then, before beginning
the account of his journey, he lets escape the precious confession
of an incredulity of which I have often heard Alpine travellers
boast, even those who had made the most difficult ascents:
However, in spite of so many data and proofs reported by these
distinguished men worthy of credence, I had been a little incredulous
and I could not help believing that imagination played a great part in
the production of these phenomena. On the main range of Monte
Rosa I had often ascended heights of more than 4300 meters without
any difficulty and without the least discomfort, and I could not believe
that 500 meters more were enough to affect an organism which had
stood the test very well up to this altitude. Now I am forced to
admit it, I have been convinced de visu, and even a little at my
expense, of the very real existence of symptoms which, above this
altitude, attack anyone who breathes and particularly anyone who
moves in this rarified air. (P. 11.)
He then comes to the account of his first ascent with Dr.
Marcet, August 16, 1869. I copy the important points of his descrip-
tion, which is remarkable for its exactness and moderation:
Up to the Grands-Mulets (3050 meters), where we arrived at 3
o'clock to pass the night, we were well; no one felt the least discom-
fort; we all had excellent appetites; but already our instruments
announced serious disturbance of circulation, respiration, and espe-
cially calorification, (heat production)
110 Historical
The night at the Grands-Mulets was horrible .... At half-past
two we set out.
At daybreak they reached the Grand-Plateau (3932 meters) :
We stopped a moment to breathe .... The guides took a little
nourishment; but it was completely impossible for me to swallow a
single mouthful, although I still felt quite well.
We climbed very slowly; we all felt an inclination to sleep which
was very difficult to struggle against and an intense occipital head-
ache, thirst and dryness of the throat, only a few palpitations, but a
wretched pulse which varied between 160 to 172 per minute.
When we reached the ridge, we were all tired, and it seemed to
me that it would be completely impossible for me to go further. None
of us vomited, but almost all of us were nauseated. Like those who are
attacked by seasickness, I was completely indifferent about myself
and the others, and I wanted only one thing, to remain motionless.
The Englishmen who were following us seemed even more affected
than we were; one of them was obliged to stop and soon retraced his
steps.
At last they reached the summit of Mont Blanc:
I no longer felt any kind of illness, but the breathlessness was
extreme as soon as I wished to take a few steps rapidly. The least
movement caused me disagreeable palpitations. One of my com-
panions, who had felt no ill effect until then, was attacked suddenly,
as soon as he had reached the summit, by dizziness and almost con-
stant vomiting which did not cease until he reached the Grand-Plateau
on the way down. His stomach was empty, so that he vomited only
glairy and bilious matter with very painful efforts. Nothing succeeded
in stopping this stomach trouble; only one thing seemed to relieve his
condition at all, that was small fragments of pure ice which he
managed to swallow from time to time. His pulse was very uneven,
very wretched, and the thermometer placed under his tongue hardly
went above +32°!
The sun was warm, the atmosphere fairly calm, so it was with
surprise that I observed that the temperature of the air was — 9°.
We remained at the summit nearly two hours to make the experi-
ments of which I shall speak later. While I was resting, I felt quite
well, although it was impossible for me to take the least nourishment.
(P. 16.)
The second ascent went much better. The night at the Grands-
Mulets was good; magnificent weather made the walking easy:
We felt almost no discomfort except a leaden sleepiness while we
were climbing the slope which leads to the Dome. I have never felt any-
thing like it, and I am sure that I slept while I was walking. But
when I reached the ridge, the cold air and rubbing my forehead with
snow removed this congestion.
I felt much better than on the first ascent. I even had an appetite
and could eat some morsels with pleasure. However, breathlessness
Mountain Journeys 111
at the slightest movement was still intense. One of our companions
experienced great nausea, complete lack of appetite, but did not vomit.
(P. 18.)
After this general description, M. Lortet passes to the analysis
of the disturbances in the various functions. And at the beginning
he is careful to say:
Hardly noticeable while going from Lyons to Chamounix, that is,
passing from a height of 200 meters to an altitude of 1000 meters,
their disturbance is, on the contrary, very appreciable from Cham-
ounix to the Grands-Mulets (from 1050 to 3050 meters), still plainer
from the Grands-Mulets (3050 meters) to the Grand-Plateau (3932
meters) ; finally this change becomes very great from the Grand-
Plateau to the Bosses-du-Dromadaire (4556 meters), and at the
summit of the Calotte of Mont Blanc (4810 meters).
We shall therefore review the variations undergone by the respi-
ration, the circulation, and the inner temperature of the body, taken
under the tongue at different altitudes, either while walking, or after
a suitable period of rest. (P. 20.)
Respiration: From Chamounix to the Grand-Plateau (from 1050
to 3952 meters) disturbances of respiration are slight in those who
know how to walk in the mountains, who keep their heads lowered
to lessen the laryngial orifice, who breathe with their mouths closed,
being careful to suck an inert object, such as a hazelnut or a little
piece of quartz, which considerably increases salivation and prevents
the drying out of the air passages. From Chamounix to the Grand-
Plateau, the number of respiratory movements is hardly changed;
while at rest, we find twenty-four per minute, as in Lyons and in
Chamounix; but from the Grand-Plateau to the Bosses-du-Dromadaire
and to the summit, we find thirty-six movements per minute. The
breathing is very short and very difficult, even when one remains
quiet; it seems as if the muscles are stiffened and the ribs are held
in a vise. At the summit, the slightest movement brings on panting;
but after two hours of rest these discomforts disappear little by little.
Respiration drops to twenty-five per minute, but it still remains
painful. (P. 20.)
M. Lortet studied the changes in the amplitude of his respi-
ration with the anapnograph of Bergeon and Kastus; the two
tracings below give a very complete idea of them; in both, the area
GFED represents the inspiration, the area DCBA, the expiration.
Comparing the tracing of Figure 1, taken at Lyons, with the
following, taken at the summit of Mont Blanc, after a rest of an
hour and a half, we see that the quantity of air inspired and
expired at the summit of Mont Blanc is much less than at Lyons.
Circulation: During the ascent, although progress is excessively
slow, the circulation is accelerated extraordinarily. At Lyons', when
I am resting and fasting, my average pulse rate is sixty-four per
112 Historical
minute. While I was climbing from Chamounix to Mont Blanc, it
increased progressively, following the altitudes, to 80, 108, 116, 128,
136; and finally, while I was climbing the last ridge which leads from
Fig. 1— Lortet. Respiratory tracing taken at Lyons (200 m.)
Fig. 2 — Lortet. Respiratory tracing taken at the top of Mont Blanc (4810
m.) after an hour's rest.
the Bosses-du-Dromadaire to the summit, to 160 and sometimes more.
These ridges, it is true, are very steep, they have a grade of forty-five
to fifty degrees; but slowness of the walking is very great. One
generally takes thirty-two steps per minute and often much less when
steps have to be cut constantly. The pulse is feverish, hasty, and weak.
It is plain that the artery is almost empty. The slightest pressure
stops the current in the blood-vessel. The blood must pass very
rapidly in the lungs, and this rapidity increases still more the insuffi-
cient oxygenation which has already resulted from the rarefaction of
the air. It does not have time to receive the oxygen adequately, and
neither does it have time to give off its carbonic acid entirely. Above
Mountain Journeys
113
the elevation of 4500 meters, the veins of the hands, the forearms,
and the temples are distended. The face is pale with slight cyanosis,
and everyone, even the guides acclimated to these lofty regions feel
a heaviness in the head and a drowsiness which are often very
painful, due probably to a venous stasis in the brain or to a failure
of oxygenation of the blood.
Even after two hours of complete rest at the summit and fasting,
the pulse always remains between 90 and 108 beats per minute.
(P. 23.)
We reproduce as very interesting examples the following
sphygmographic tracings (Figs. 3, 4, 5) which, made by M.
Chauveau of Lyons at the time of his ascent in 1866, give all neces-
Fig. 3 — Cupelain; at Chamounix (1000 m.)
Fig. 4— Cupelain; at the Grands Mulets (3000 m.) at midnight, one half-
hour before starting.
Fig. 5— Cupelain; top of Mont Blanc (4810 m.)
sary proofs of accuracy. The guide Cupelain, who was the subject,
is a very vigorous young man, who seems not to suffer from moun-
tain sickness at all.
For M. Lortet, who does suffer from it, the changes were still
more considerable.
Temperature. We now come to the subject to which M. Lortet
gave most attention, and which serves as a basis for his theory of
mountain sickness. I continue to quote verbatim:
The thermometer was placed under the tongue, the buccal orifice
being always closed hermetically, and respiration going on only
114 Historical
through the nose .... The instrument was always left in place for
at least fifteen minutes. (P. 31.)
Fasting, while walking continues, the decrease of the tempera-
ture is, according to M. Lortet, almost proportional to the altitude
at which one is. This is shown by the following table.
Lortet: Temperature
First
Second
Temperature
Ascent
Ascent
of the
air
<u
Places
<D
tuO
3
gg,
3
a;
'B
a>
'x
First
Second
in .fj
<
'3
OS
'3
Ascent
Ascent
3 «
Chamounix
1050
36.5
36.3
37.0
35.3
+ 10.1
+ 12.4
64
Cascade du Dard
1500
36.4
35.7
36.3
34.3
+ 11.2
+13.4
70
Chalet de la Para
1605
36.6
34.8
36.3
34.2
+ 11.8
+ 13.6
80
Pierre-Pointue
2049
36.5
33.3
36.4
33.4
+ 13.2
+ 14.1
108
Grands-Mulets
3050
36.5
33.1
36.3
33.3
— 0.3
— 1.5
116
Grand-Plateau
3932
35.3
32.8
36.7
32.5
— 8.2
— 6.4
128
Bosse du Dromadaire
4556
36.4
32.2
36.7
32.3
—10.3
— 4.2
136
Summit of Mont
Blanc
4810
36.3
32.0
36.6
31.0
— 9.1
— 3.4
172
So during the muscular efforts of the ascent, the temperature of
the body may drop four or five degrees, when one mounts from 1050
to 4810 meters. As soon as one stops for a few minutes, the tempera-
ture rises quickly to nearly its normal figure ....
Since my return to Lyons, I have observed that when one ascends
rapidly one of the numerous stairways that lead to Fourvieres or the
Croix Rouge, there is regularly a drop in temperature which varies
almost always from three to seven tenths of a- degree. (P. 32.)
It is to this drop in temperature of the body that M. Lortet
attributes all the symptoms of mountain sickness. In Chapter III
we shall give this theory and the objections it has aroused.
The same day when MM. Lortet and Marcet suffered so severely
during the ascent, M. Ch. Durier150 followed them, walking, so to
speak, in their footsteps. Strangely enough, neither he nor his
companions felt any symptoms:
There were three of us, three companions of very different
temperament; one was a lad fifteen years old, the youngest traveller —
at least that I know of — ever to ascend Mont Blanc. Well! None of us
felt the slightest discomfort, not even breathlessness. (P. 66.)
Why this difference in impression? M. Durier asks himself.
And to this question he gives an answer full of acuteness, of which
we shall make use later.
Mountain Journeys 115
I shall end the review of the principal ascents of Mont Blanc
with that of M. Albert Tissandier;1M it is particularly interesting
because its author, being an aeronaut, could compare his sensa-
tions with those he felt in a balloon; he had no uncomfortable
sensations:
At the height of 4400 meters, respiration began to be somewhat
painful and panting, but I endured the effect of the rarefaction of the
air without very much trouble. My two guides looked at me at that
time, and told me that often, at that altitude, travellers have a
peculiar color; sometimes their vision grows dim and their strength
fails; then they have to be hoisted up with great difficulty or else
descend, depending upon the energy the traveller possesses.
I should have been very sorry to be obliged to descend. In a
balloon I have reached altitudes almost equal to that of Mont Blanc
without being inconvenienced; but a mountain ascent, slow and
painful, is not at all like the ascent one makes so quickly and easily
in the basket of a balloon.
The ascent of Mont Blanc, so much feared before the daring
attempt of Jacques Balmat, and which the sufferings of De Saussure
and then the accident of Dr. Hamel had invested with a terrifying
renown, has in our time become frequent, almost common. In 1873,
sixty travellers ascended to the summit of the giant of the Alps,
among them seven women and a lad of fourteen, the youngest
who has ever made the ascent, named Horace de Saussure. Since
the time of the illustrious ancestor of this brave lad, I have
counted on the list still incomplete given by M. Besangon,1"'2 which
goes to the end of 1873, 828 ascents, 27 of which were made by
women. The last, made by an Englishwoman, Mrs. Straton, shows
remarkable courage; it took place January 31, 1876; on the summit
the lady found a temperature of —24 degrees. But the large majority
of these expeditions offer no scientific interest; they are mere
tourist excursions, often managed very imprudently. Mont Blanc,
of which the professional "mountaineers" speak with a certain
disdain, seems to avenge itself; there have been more serious acci-
dents upon it than in all the rest of the Alps. One of these disasters,
the most terrible of all, perhaps has some relation to our subject.
September 6, 1870, nine guides and three travellers reached the
summit of Mont Blanc; they could not get down, and died the next
day in the snow. In the pocket of one of them, M. Beau,1"3 was
found a paper giving an account of their sufferings:
We passed the night in a cavern dug in the snow, a very uncom-
fortable shelter; I was sick all night.
116 Historical
Most of those who have made recent ascents of Mont Blanc,
the accounts of which have been preserved for us by the Alpine
clubs, say nothing of mountain sickness. They go on at length
about the preparations for the departure, the petty incidents of the
journey, the joys of the return, but maintain complete silence
about the physiological phenomena. And what I say of Mont Blanc
is true of all the other ascents, even of mountains rivaling it in
height. I have gone over, page by page, the journals of the English,
Swiss, Italian, Austrian, and French Alpine clubs; I have patiently
read hundreds of monotonous accounts, and have found very few
data relating to our study; I shall mention them chronologically.
August 13, 1857, M. Hardy ir'4 made the ascent of the Finster-
aarhorn (4275 meters) :
Wellig (inn-keeper of Eggischhorn), considering himself insulted
by our jokes, went on ahead to reach the summit first. But hardly
had he taken a hundred steps, when he fell as if some one had shot
him. Ellis, who was walking behind him, thought that he was resting,
and walked quietly up to him; but when I came, I perceived that it
was more serious. His eyes were turned up, his mouth open, and he
looked strangely like a fish. I did not know what to do; but Cruz
adopted a queer mode of treatment .... He raised him to a seated
posture and shook him so vigorously backward and forward, that after
a few vibrations he revived from his faint, got up, and went to join
Fortunatus. (P. 299.)
Perhaps we may hesitate to attribute this sudden syncope to
mountain sickness; but in the narrative of Tuckett,15"' the doubt is
not possible.
The matter in question is an ascent on Grivola (3960 meters),
made in June 1859; an avalanche threatened to carry away the
travellers:
Chabot, one of the guides, complained of painful sensations in
the chest and stomach, loss of appetite, vertigo, nausea, headache,
resulting partly from fear and fatigue, and partly also, perhaps, due
to the rarity of the air, for we had reached the height of 12,028 feet
(3665 meters). (P. 297.)
In my opinion, in spite of the complication of a somewhat
exaggerated consumption of alcoholic beverages, the influence of
rarified air is incontestable again in the following observation158:
A young Englishman about twenty-four years old, a regular
picture of health and strength, passed the Weissthor by Macugnagna.
He was not much accustomed to difficult ascents .... and to give
himself strength drank brandy and water frequently. The result was
soon seen. The guides had to pull him along with ropes, in a state of
Mountain Journeys 117
complete exhaustion .... In fact, as he told me, he has no notion
of the way in which he overcame the difficulties and reached the
summit; he was in an inert stupor the whole time. (P. 349.)
M. Kennedy,157 one of the most daring and one of the first men
to make ascents in the Alps, was himself attacked in one of his
expeditions, not the first, far from it, nor the most difficult, nor
the highest; he was climbing the Dent-Blanche (4365 meters) and
was still far. from the summit:
An extraordinary weight seemed to be loaded on me, hampering
my movements. My legs, although I did not feel fatigued, refused to
act with their usual vigor, and I was left far behind; but the pure and
rarified air which blew over us and the sight of the peak of the Dent-
Blanche began to revive me. (P. 36.)
In certain accounts, it is only incidentally, as if buried in a
sentence, that we see the symptoms of mountain sickness
appearing:
Guides and travellers were exhausted, stopping often for breath 15S
.... (P. 107.)
In other cases they are more clearly indicated, even described.
The snow was hard, it was necessary to cut steps, and more159
than once the travellers had to stop to get their breath. (P. 166.)
In 1864, Craufurd Grove160 ascended to Studer-joch (3260
meters) ; too great speed in walking made travellers and guides ill:
Perru, who was afraid of avalanches, made us walk at a pace
unusual in the Alps, which quickly produced signs of distress in the
whole group; .... but the robust son of Zermatt gave no heed, and
slackened his pace only when the outraged laws of respiration claimed
their rights and compelled him to stop completely to get his breath . . .
We reached the summit; but our joy was greatly lessened by the fact
that we were almost all ill. Some of us who had relaxed beside
Italian lakes from the hard work of the mountaineer had eaten figs
and grapes in excess. The result of this diet, while we were walking
on the ice, was too painful to be described. The guides were in a
hardly less pitiful condition; they had drunk Grimsel brandy the night
before. (P. 368.)
The account of the ascent of Monte Rosa by Visconti,"'1 in
August, 1864, is still clearer and more interesting:
The rarefaction of the air inconvenienced us greatly, either
because of the difficulty in breathing or because of the decrease of
atmosphere pressure on the blood-vessels. For these reasons and
because of the steepness of the grades, our legs and lungs tired
quickly; but a few moments of rest restored their strength rapidly . . .
118 Historical
Just before we reached the summit (4640 meters), we met the
English travellers coming down. One of them was pale and disturbed;
he • told me that the rarefaction of the air had caused frequent
vomiting which had weakened him; in addition, he was dizzy. I merely
felt a weakness of the stomach with frequent nausea. (P. 160.)
Last I shall report an observation made by M. Gamard,1"-' dur-
ing his ascent of the Jungfrau (4170 meters), August 24, 1874,
which we shall discuss later:
We were buried in the very side of the mountain; air failed us,
and as we noticed on Monte Rosa and Mont Blanc, it is not at the
summit that we suffer from this rarefaction, but in spots which the
wind does not reach.
At half past nine, we rested again; we were at an altitude of
about 3750 meters. (P. 216.)
But, I repeat, observations of this sort are extremely rare. Ball
does not say a word about mountain sickness in his useful work
entitled Suggestions for Alpine Travellers,1™ in which he enu-
merates the dangers of ascents and the principal observations of
physics and natural history which can be made there.
Does this mean that everything has changed since the time of
De Saussure, and that today one can safely make ascents which
then were painful and difficult? In this hypothesis, however
strange it may appear at first thought, there is a portion of truth,
the amount of which we shall discuss later. But to make sure that
the immunity is anything but general and complete, we need only
question carefully those who make ascents, even those who in
their accounts do not mention physiological disturbances, even
those who deny the existence of such disturbances. Moreover, M.
Joanne, who has read and seen and heard so much, summarizes
perfectly in his excellent guidebook to Switzerland 104 all common
knowledge on this point:
The lightness and the great rarity of the air in the Alps, and the
energy with which it speeds up evaporation cause at certain altitudes
very noticeable physiological phenomena, such as considerable
decrease or loss of appetite, distaste for food, nausea, drowsiness,
panting, headache, fainting, etc.; some of these symptoms even compel
certain individuals to turn back at once, as soon as they have reached
an altitude of 3000 meters; at about 3400 meters, mules are so out of
breath that they utter a sort of plaintive cry. However strength returns,
in such a case, as quickly and apparently as completely as it was
exhausted. Mere cessation of movement seems, in the short space of
three or four minutes, to restore it so perfectly that when one starts
walking again, one no longer feels any fatigue. (P. 93.)
Mountain Journeys 119
But if these symptoms are so frequent, why not speak of them,
or at least why not mention them in accounts which are often so
prolix and loaded with uninteresting details?
In the first place, we must confess, their importance and sever-
ity have been so exaggerated that travellers affected only by
panting and palpitations are willing to deny even the reality of an
illness which they dreaded so much in advance. In this connection,
I found an interesting indication in the account of ascents made in
August, 1859, of Grivola (3960 meters) by M. Ormsby.165 He was
climbing the "chimney" in a very dangerous position when he had
a very strange dizzy feeling, and he adds:
I had read so many terrible stories of the strange effects of the
rarified air on man at great altitudes that I began to be very nervous
.... It was the moment to be attacked by apoplexy, catalepsy,
bleeding from the eyes or some other of the terrible symptoms. (P.
333.)
In the second place, most of the tourists whose narrations fill
the Alpine journals have hardly any scientific interests in their
ascents; they climb for the sake of climbing, or seeing, or often of
telling that they have climbed and seen. It is generally this last
feeling which dictates their accounts, and that is why one sees
them every year seeking some horn, spitze, or joch, hitherto inac-
cessible or merely forgotten: a virginity often hard to conquer,
the sterile conquest of which they will dispute.
Finally, a point of honor has intervened; they are almost as afraid
of being ridiculed for mountain sickness as they are for seasick-
ness. Formerly, they sought its symptoms in themselves, they
liked to boast of having experienced them, as they would have
boasted of a mysterious danger they had risked; today they refuse
to observe them, especially to admit them; sometimes they deny
them.
One of the travellers of our period who are most experienced
in mountain climbing, Count Henry Russell,1'0 expresses himself
on this point with the greatest clearness and authority:
I regret to state that some of the most important authorities of the
Alpine Club have gone so far as to deny completely a thing like the
painful phenomenon known in all countries by the name of "mountain
sickness", or they declare it an exception, an effect of fatigue, of
exhaustion. It is true that very favored lungs can go to very high
altitudes and continue to breathe comfortably. Likewise, there are
travellers who are immune to seasickness, and we can therefore deny
this sickness as well as the other. Mountain sickness is an ailment
which has been felt all over the earth (even in the tropics), in the
120 Historical
Andes, on the Altai, on the Himalayas .... everywhere. No animal
is immune to it, at a certain height; and as for me, I confess humbly
that I can hardly breathe on the summit of Mont Blanc; in fact, we
were all sick, more or less, including the guides. On the Calotte,
where the slope is very gentle, not one of us could take more than
thirty-four steps without pausing a long time. And that was not
fatigue, because in two hours we were descending to the Grands-
Mulets, in very good health and full of vigor. (P. 243.)
How few "mountaineers" and "Alpinists" will have courage to
make a similar confession!
6. The Pyrenees.
Since the highest mountains of the Pyrenees do not attain 3500
meters, the symptoms due to decreased pressure can be felt there
only under exceptional conditions. So travellers generally do not
mention this subject, and when they speak of it, it is usually to
declare that they have had no such experiences.
The first author to mention physiological phenomena observed
in the Pyrenees is Robert Boyle,107 but he gives only second-hand
information:
A gentleman of learning had made the ascent of the peak of Midi
in the month of September. I asked him whether he had found the
air on the summit as plentiful for breathing as that belew. He said
no, that he was forced to breathe more frequently and less deeply
than usual. And as I thought that perhaps that came from the move-
ment, I asked him whether this difficulty had ceased after his arrival
at the summit; he answered: "Yes, evidently, for we could not have
remained several hours on this summit with such difficulty in breath-
ing." (P. 2039).
During the eighteenth century, a fairly large number of ascents
were made, for scientific reasons, on different mountains of the
Pyrenees, and those not the least lofty. The book of Dralet 1<1S
gives an interesting summary of the data formerly observed:
The artists who were employed in 1700 in constructing on Canigou
a pyramid for determining the meridian felt no symptom. MM. Vidal
and Reboul passed three days and three nights on the summit of the
peak of Midi of Bigorre without any inconvenience; I have always
been immune, and so have my travelling companions, not only on this
same peak, but also on the loftiest ridges which separate France from
Spain .... However some travellers have been affected in the
Pyrenees, even at moderate heights. In 1741, M. Plantade, celebrated
astronomer of Languedoc, died at the age of 70 beside his quadrant,
on the Hourquette des Cinq-Ours (1244) fathoms. Count Dolomieu, in
August, 1782, almost met the same fate; he was attacked by a violent
fever which kept him from reaching the summit of the peak10';
Mountain Journeys 121
M. de Puymaurin and M. Lapeyrouse, his travelling companions, were
for an instant almost without pulse. M. Dusaulx, before reaching the
plateau of the peak of Midi, felt dizziness and a sort of weakness,
without his companions experiencing any such symptoms. These facts
seem to prove, according to the opinion of M. de Saussure, that nature
has fixed for the constitution of each person the altitude to which he
can ascend without discomfort and without danger. But it should be
noted that certain travellers have been affected at a moderate height,
although accustomed to climbing very high mountains without any
trouble. (Vol. I, p. 38.)
After that time, the traveller and naturalist Ramond made the
first ascent of Mont Perdu (3350 meters). His very interesting
account 17° gives proof of very uncommon sagacity; at least he does
not deny what he was fortunate enough not to feel:
We were breathing without difficulty this light air which was no
longer sufficient for the respiration of many others. I have seen
vigorous men forced to stop at much lower elevations . . . Here we
felt nothing of the sort; only the condition of the pulse indicated a
change independent of the excitement of the trip: rest did not quiet
it. As long as we remained on the summit, it was small, dry, difficult,
and quickened in the ratio of 5 to 4; this fever, which is nervous,
announced plainly the illness which we should have felt at a greater
elevation; but at the point where we were affected by it, it produced
an effect just the opposite of that which a degree more would have
produced. Far from causing exhaustion, it seemed as if it aided my
physical powers and raised my spirits. I am convinced that we often
owe to it this nimbleness of limb, this acuteness of the senses, this
activity of thought which suddenly dispel the prostration of fatigue
and the apprehension of danger; perhaps we need not seek elsewhere
the secret of the enthusiasm which permeates the accounts of all who
have mounted above ordinary heights. (P. 84.)
Likewise Arbanere 1T1 declares that on the summit of Mont Perdu
in 1821 he:
Experienced no effect of the rarefaction of the air, that distress,
that anxiety, that nausea which often cause prostration at such a
height. (Vol. II, p. 85.)
On Vendemiaire 11, in the year XI, Cordier and Neergaard
made the ascent of the Maladetta. One of them was seriously
affected; here is the account the celebrated geologist gives of this
complication:172
Shortly afterwards, the ridge became wholly impassable and we
had to go out upon the glacier. We were then at a height of about
3000 meters. M. Neergaard was so distressed by nausea and dizziness,
caused by the rarity of the air, that it was absolutely impossible for
him to go any further. I will note, by the way, that mountain sickness
122 Historical
almost always attacks the small number of persons whom a natural or
accidental tendency makes subject to it, at the height of 2600 to 3000
meters, immediately above the timber line. (P. 266.)
Cordier and his guide continued on the way and reached the
summit without seeming to have experienced any unpleasant
symptoms; at least the account gives no signs of any.
A traveller of whom we have already spoken, who made
numerous ascents, particularly in the Pyrenees, Parrot,173 gave
special attention to the variations in his pulse at different heights.
I reproduce his important observations:
My pulse rate on the summit of Mont Perdu was 110, and a few
days before, in my first attempt to climb this mountain, it was 100.
Upon the Maladetta, it was 103, and some days before, at Bagneres de
Luchon (628 meters), it was only 70. These variations are in a regular
ratio with those of the height; they agree with the observations which
I have already made on my pulse on different mountains. So my
pulse rate, which is 70 at sea level, rises to 75 at a height of 1000
meters, 82 at 1500 meters, 90 at 2000 meters, 95 at 2500 meters, 100
at 3000 meters, 105 at 3500 meters, 110 at 4000 meters. (P. 216.)
After him, I have hardly anything else to quote but the account
of M. de Franqueville,174 who was the first to ascend the highest
peak of the Pyrenees, the peak of Nethou (3400 meters) .
The ascent took place July 18 and 19, 1842. The travellers
reached the glacier of Nethou, very near the goal of their ascent:
We were all expecting to feel some of the symptoms due to the
rarefaction of the air, which generally add still more to the difficulties
of great ascents. However this did not occur. But after making a few
steps on the glacier, M. de Tchihatcheff was attacked by nausea so
violent that he was forced to stop from time to time and lie down on
the snow. A few moments of rest revived him completely, and per-
mitted him to go on. As for the rest of us, neither the guides nor I
felt anything special. We did not even have to struggle against this
lassitude, this distress which are so painful and which so often
accompany, they say, the presence of man in these lofty regions which
were not made for him.
Here ends all related to our subject that we have been able to
find in the narratives of mountaineers in the Pyrenees. A strange
document shows us that nothing important ever attracted their
attention. Count Russell-Killough, who knows the Pyrenees so
marvellously, has published a collection of ascents of the peak of
Nethou, from the one which we have just mentioned up to 1868.
In this interval, there were about two hundred, including nearly a
thousand persons, twenty-two of whom were ladies.
Mountain Journeys 123
The book, which contains the personal notes of each tourist,
shows absolutely nothing, except the general vanity of motives
which impelled so many persons to this painful ascent. Physio-
logical symptoms are not even mentioned. Count Russell alone
(August 24, 1863) says: "no spitting of blood". (P. 50.)
Finally, I will quote in this section a few observations 17,! made
in an ascent of Mulahacen, the highest peak of the Sierra Nevada
of Spain; they contain the outline of a strange theory:
The effects produced by the rarity of the air upon the lungs and
the body were not felt as long as we remained on the mules. But
now that we had to make muscular efforts, a greater shift of energy
is necessary than in a dense atmosphere. The equilibrium of the air,
which supports the bones as the water does for fishes, fails, and the
muscles are forced to lift a greater weight; hence exhaustion. (P. 157).
7. The Caucasus, Armenia, Persia.
Caucasus. The ascents of the lofty summits of the Caucasus are
quite recent. Klaproth,177 in the account of his journey to Mount
Caucasus and Georgia, made in 1807-1808, said:
No one has ascended Elbrouz; and the Caucasians think that no
one can reach its summit without special permission from God. (Vol.
I, p. 131).
A very serious attempt to ascend to the summit of Kasbek or
Mquinvari (5030 meters) was made September 17, 1812, by
Engelhard and Parrot.178
The two travellers camped at the line of perpetual snow; Parrot
alone undertook the ascent to the summit. He had to surmount
the usual mountain difficulties; but, he adds:
The most annoying thing to me was a strange lassitude which
forced me to rest every fifty steps; it arose less from oppression
of the chest than from a complete weakness of the muscles which
seized me suddenly, and which soon passed when I stopped for only
a half-minute. It was generally followed by a strange and agreeable
sensation, as if I were in a new element, to which my body, made for
the stronger pressure of the lower regions, was superior in strength.
An inevitable consequence of the extremely rarified air which sur-
rounded us was the acceleration of the pulse and the respiration; but
distress and vertigo troubled neither me nor my companions. In
return, I observed in them and myself a weakening of several sense
organs; we were obliged to talk very loud to make each other hear;
we had difficulty in talking, not because respiration failed us, but
because our tongues had lost their flexibility; even the eye seemed
less active, and one would have said that an inner cause prevented
it from seeing distinctly and at a great distance. (P. 302.)
124 Historical
Parrot was forced to stop at an elevation of 2168 fathoms; he
passed the night with his companions, but had to descend the next
day without having reached the summit, which he estimates has
a height of 2400 fathoms.
In 1829, a military and scientific expedition approached Mount
Elbrouz (5620 meters) ; Kupffer 17;' and the other scientists who
were in the party resolved to attempt the ascent of the giant of
the Caucasus.
July 22, 1829, they reached the line of perpetual snow upon
its sides:
We were forced to stop at nearly every step. The air is so rarified
that respiration is no longer able to restore the strength that one has
lost; the blood is in violent movement and causes inflammation in the
weakest parts .... All my senses were blunted, my head whirled,
I felt from time to time an indefinable dejection which I could not
control .... We were then at a height of 14,000 feet above sea level.
(P. 33.)
However they had not reached the altitude of Monte Rosa;
they could go no higher, but one of their guides ascended to the
summit.
Sjogrun,180 who, May 26, 1836, made the ascent of "the highest
mountain of the Caucasus" (his account is not clear, but I think he
means Kasbek) , says absolutely nothing of physiological disturb-
ances.
But Radde,181 although his ascent of Elbrouz August 10, 1865,
was not completed because of bad weather, shows clearly in his
account the effect of rarefied air:
Before us rose, all white, the summit of the mountain. A strong
west wind had risen. We stopped a certain time; weariness and
dizziness painfully affected my two companions and myself; we like-
wise experienced a strange weakness of the knees, which soon checked
all our movements ....
We stopped more and more often; dizziness and weakness of the
knees increased; horrible fatigue (entsetzlich) weighed me down.
We had reached a height of 14,925 feet (4557 meters). (P. 102.)
In their journey, in 1868, Douglas W. Freshfield, Moore and
Tucker,182 accompanied by a guide from Chamounix, Fr. Devouas-
soud, with whom they had made ascents in the Alps, made the two
difficult ascents of Kasbek and Elbrouz.
July 1, ascent of Kasbek; night passed at a height of 3300
meters; except for the excessive fatigue which forced one of them
to lie down and nearly prevented another from reaching the
summit, our travellers notice nothing to interest us.
Mountain Journeys 125
July 31, ascent of Elbrouz; they complain only of the cold.
Gardiner, Grove, Walker and Knubel 183 ascended to the summit
of Elbrouz July 28, 1874. July 27, they camped at a height of
11,300 feet, and the next day reached the summit:
Everyone suffered from the rarity of the air. In 1868, not one
felt its effects; the peak ascended then was probably that of the east;
but the difference in height, if there is any, is too slight to explain
the immunity of the former expedition.
It is probably the journey of Douglas Freshfield and others that
is referred to here.
In the same publication is a second account, by Gardiner,184 of
the same ascent:
After we left the col, no serious difficulty appeared. However
Grove, Knubel and I suffered more or less in breathing, which forced
us to stop often; we also had what I have heard a Swiss guide call
"a blow in the knees". Walker had the nosebleed, but no other
symptom. (P. 119.)
Armenia. The plateau of Armenia, which over a vast expanse
has an average altitude of over 3000 meters, is dominated by the
double summit of Ararat, which was well known by the ancients
and of which the books of the Bible speak, as everyone knows.
But if Noah, according to the legend, could easily descend from
the summit to which' the waters had carried him— which, if they
had covered the lofty Ararat, would have left above them only its
neighbors Elbrouz and Demavend with the highest peaks of the
Andes and the Himalayas,— the ascent of the holy mountain offers
quite serious difficulties. However, Pierre Bergeron, a Parisian, in
his treatise on the Tartars,185 gives us the following curious infor-
mation:
Elmacin, an Arabian historian, relates that when the emperor
Heraclius was making war in Persia, and passed by the city of
Themanin, built, they say, by Noah on leaving the Ark, curiosity
urged him to ascend this mountain (Ararat, which is the Taur, as the
Scriptures call it, and the Greeks call it Periarde; today, it is
Chielder), to see whether he could find any remains of this vessel.
Haiton says also that in his time there were a few pieces left. (P. 66.)
It is also to Robert Boyle186 that we owe the first account of
an ascent of Ararat, with mention of the discomforts produced by
a stay in so lofty a place:
Having met an ecclesiastic who had ascended the lofty mountains
of Armenia (on one of which, because of its great height, the people
of the country say that the Ark came to rest), I asked him whether
126 Historical
he had had any difficulty in breathing on the summits .... He ans-
wered that he had not been able to reach the tops of these mountains
because of the snow; that, however, he had noticed that he was obliged
to breathe more frequently.
I asked him whether this difficulty seemed to him accidental or
peculiar to him; but he assured me that it was general on lofty places
and was commonly observed.
This same ecclesiastic felt similar respiratory symptoms when
he made the ascent of a mountain in the Cevennes. (P. 2038.)
The celebrated botanist Tournefort, who attempted the ascent
on August 11, 1701, could not go even to the snow line:
One (he says) complained that he could not breathe; as for me,
I had never been so afraid that some lymph vessel would burst in
my body. (Vol. II, P. 316.)
The first complete ascent of which we have a record is the one
made in 1829 by Parrot, the learned traveller whom we have
quoted so often already; he had to make three attempts.
September 12,1SS he ascended only to 3850 meters (p. 130) ;
September 18, he reached 5000 meters (p. 146) . Finally, September
26, he passed the night at 4300 meters; he complains only of a
feeling of fatigue and a tendency to sleep (P. 156.) The next day,
departure for the summit:
We had to leave one of our peasants sick at camp. Two others,
over-tired by the ascent of the glaciers, lay down on the ground, then
went back down. Without letting ourselves be discouraged, we
continued on our way. (P. 157).
The rest of their account shows that their fatigue was extreme;
but no other symptom is noted. At a quarter past three, they
reached the summit: "My first desire and my first pleasure was
rest", says Parrot. (P. 159.)
The difficulties with which popular opinion surrounded an
ascent which seemed a trifle sacrilegious caused this circumstan-
tial and credible account of Parrot to be called in question. But
a few years later other explorers, Avtonomoff,189 August 5, 1834,
Behrens,190 July 20 and August 9, 1835, Abich,1"1 July 29, 1845,
proved its exactness. I could not get the complete account of these
ascents, and the reports of them given by the journals of geo-
graphy do not mention any physiological disturbance.
But that proves nothing, for they are equally silent when they
discuss19-' the celebrated ascent of the Russian Colonel Chodzko,
and yet it appears from a communication the learned geodesist
sent me that these disturbances were anything but negligible.
Mountain. Journeys 127
Here is the account as it was given me in a letter written in
French by General Chodzko: I quote it in full, thanking my emi-
nent correspondent sincerely for his kindness. The expedition
included five officers and sixty soldiers:
The ascent began July 31 (August 11), 1850. From August 4 (16)
to August 6 (18), we remained in our tents at the foot of the summit
of Mount Ararat. August 5 (17), during the night, sheltered under
perpendicular cliffs, we remained from eight to eleven o'clock in the
evening in the midst of electrically charged clouds. The lightning
flashes which one sees from below crossing the clouds like mere thin
ribbons had enormous dimensions; the thunder roared at the very
instant when the flash appeared; it was like the fire of a volley of
cannons. After a storm of three hours, a very loud clap of thunder
detached a part of the cliff, which fell with a crash.
After the thunder storm was over, hurricanes of snow came on.
It was a very difficult task for us to unroll and stretch a little higher
two little canvas tents, under which we remained from the 16th to the
19th of August. August 18, after reaching the summit, we set up there
a cross painted black. Two tents were pitched in holes dug in the
snow. August 19, the observations of the zenithal distances were begun
(Ararat was observed from 122 trigonometric points); they were
finished after a fashion on the morning of August 24. We set out at
noon, and descended rapidly.
As for physiological symptoms, my head was very heavy; it
seemed to me as if an iron ring pressed my skull above the ears.
We had to walk very slowly in order to breathe easily. At night,
when we were sleeping wrapped up in pelisses, if the cold penetrating
through them awakened us, the movements we made to pull them
around us cut off our breathing. The third day my head became
lighter; but it was still impossible to walk quickly.
In their journey to Armenia, Radde and Sievers made some
fairly lofty ascents, among them one of a mountain near the lake
of Chara-Gol, July 28, 1871:
At an altitude of about 12,300 feet (says Radde) 1Da I had to stop.
My respiration was difficult, my knees were absolutely broken. I
began to be feverish .... Sievers climbed bravely on. I remained
lying down completely apathetic, for two hours, awaiting his return.
At the end of about two hours, he returned, as sick as I, completely
exhausted and broken. (P. 177.)
Among the numerous travellers who have traversed Asia Minor
in all directions, I find only one, Hamilton,194 who made the ascent
of Argaeus (3840 meters), July 30, 1837. He says absolutely
nothing of physiological disturbances.
Persia. But I have found two accounts of ascents of the extinct
volcano of Demavend (5620 meters), near Teheran.
128 Historical
September 8, 1837, Taylor Thomson 195 camped on the mountain
side at an elevation of 2000 meters. The next morning, he set out:
I had not been climbing more than an hour, when two of my men
refused to go any further .... I kept on with the other two, but one
of them complained so bitterly of headache and palpitations that I
had to let him go back. By entreaties and threats I kept the other as
far as the crater: the cold was extreme .... The temperature was
56 °F., the barometer stood at 15.05 inches .... which corresponds to
14,700 feet (4480 meters).
The other ascent was made July 24 and 25, 1858, by members
of the different European missions to Teheran. The English
attache, R. F. Thomson, has given a detailed account of it.196
On July 24, camp was made for the night at the village of Rina
(3920 meters); the thermometer registered 0° centigrade. On the
morning of July 25, they set out early:
The ascent of this part of the mountain brought on great fatigue
especially on account of the rarefaction of the air which began to
affect our lungs ....
The last part of the ascent of Bamshi Bend was extremely painful
because of the rarefaction of the air. We felt nausea and violent
headache and a great difficulty in breathing, even while resting. M.
de Saint-Questin, of the French mission, and M. Castelli, a Sardinian,
who accompanied us, were affected like us. When we had rested a
little and were less tired, we began our observations. They indicated
the enormous height of 21,520 feet (6560 meters).587
We remained at the summit about an hour and a half. (P. 15.)
8. Central Asia.
In the last half of the thirteenth century, a famous traveller,
Marco Polo,198 was the first European to penetrate into the lofty
regions of the plateaux of Central Asia. The celebrated Venetian,
no doubt, as has been proved by the testimony of those who fol-
lowed his steps five hundred and fifty years afterwards, must
have felt the phenomena of which we shall soon give many
descriptions, and must have observed their effects upon his com-
panions and his beasts of burden; but his account gives no
suggestion of it:
Always one rides through mountains, and mounts so high that it
is said that this is the highest spot in all the world. (P. 130.) . . . .
No flying fowl is there, because of height and cold. And I tell
you that fire, through this great cold, is not so bright nor so warm as
in other places, nor can it cook viands so well. (P. 133.)
This place, the highest in the world, is, as the English traveller
Mountain Journeys 129
Wood showed later, the plateau of Pamir, at an altitude of 4700
meters.
Chinese travellers, still earlier, had visited these lofty places.
For instance, the pilgrim Fa-Hian189 in the year 399 crossed the
pass of Karakorum (5690 meters). Also the celebrated Hiouen-
Thsang200 coming from China found "a series of mountains and
valleys and peaks of prodigious height. He crossed black moun-
tains." (P. 55.) M. Stanislas Julien declares that this means the
passes of Hindou-Kouch and the plateau of Pamir. But in the very
brief reports left us there is no mention of physiological obser-
vations.
The description "of the provinces Wei and Zzang" of Western
China, which, published in Chinese in the year 1792, has been
translated into French by Klaproth -01, contains some indications
which, as we shall see later, evidently refer to the symptoms of
decompression.
In mentioning disturbances which affect travellers in these
lands of lofty mountains, the Chinese author speaks of:
Heat of the body, headaches, and other diseases peculiar to the
climate. (P. 23.)
Later, in an itinerary remarkable for the accuracy in distances
and the abundance of details, he mentions the influence of poison-
ous plants, which we shall soon see playing a great part in the
narratives of travellers; here, it is rhubarb which is blamed:
Leaving Djedo, one travels from mountains to mountains; they
extend a long way, but they are not very high. Rhubarb is abundant
there; it exhales a very strong odor which annoys the traveller very
much. (P. 188.)
Finally, after plants, come exhalations from the ground:
Further to the west of Djaya, one crosses a great snowy mountain;
the road is very steep. The accumulated snow looks like silvery vapor.
The mist which the mountain exhales penetrates the body and makes
the Chinese sick. (P. 210.) ....
From Lang Thang Keou, one follows the valley, ascending . . .
The frozen snow makes the road slippery and very dangerous. There
are also pestilential exhalations there. (P. 217.)
During the seventeenth and eighteenth centuries, some Euro-
pean travellers, missionaries, merchants, soldiers, or adventurers,
visited the lofty regions of Central Asia, either in the Chinese
Empire, or in that of the Grand Mogul.
Only in one account, that of the Portuguese Jesuit Antonio
130 Historical
d'Andrada,202 have I found clear indication of symptoms which
one can attribute to the effect of the air of lofty places. This mis-
sionary had the courage to cross the Himalayas almost alone on
his way from Cashmere to Tibet:
There begins a region of lofty mountains which one cannot cross
in less than 20 days. There is nothing there but rocks almost always
covered with snow ....
Partly from disease and partly from a certain pestilential
exhalation from the ground, suddenly one feels a violent inward
revulsion which kills in a quarter of an hour. I attribute these
sudden deaths to the cessation of natural warmth which is checked by
the great cold, and especially to poor food. (P. 13.)
But as for him and his two companions, he complains only of
the extreme cold, partial freezing, numbness of hands and feet,
and "loss of appetite" (P. 16), the only symptom which one can
attribute to decreased pressure. However they had passed through
very lofty regions, since they "reached the summits of all those
mountains where lies the lake whence issue the river Ganges and
another which waters the lands of Tibet" (P. 16). It is evidently
Lake Manasarowar that d'Andrada means.
Dr. Bernier,2"3 who in March, 1663, followed the Grand Mogul
Aureng-Zeb from Lahore to Cashmere, had to cross a lofty moun-
tain, still covered with snow; but he speaks only of the cold, and
alludes only to the difficulties of the trip in speaking of the
journeys of the merchants who go to Kashgar and Tibet across the
lofty ranges.
The accounts of Father Verbiest,204 who in 1683 accompanied
the Emperor of China into Eastern Tartary, and those of Father
Gerbillon,205 from 1688 to 1698, mention no sufferings.
In October, 1714, Father H. Desideri left Lahore for Cashmere,
"across the Caucasus", as the Himalayas were called for a long
time. May 17, 1715, he undertook the terrible journey through
Tibet, and reached Ladak June 25. Among his discomforts he
mentions only fatigue, cold, wild winds, and the reflection of the
sun upon the snow.200
In the second half of the eighteenth century the political rela-
tions of the English with Boutan and Tibet begin. In 1774, Bogle
was sent to the Grand Lama by the governor of India; J. Stewart,207
who has narrated his journey, makes no allusion to the effect of
the mountains.
In 1783, Samuel Turner 20S was entrusted with the same mission.
He crossed the high passes of Boutan, and stayed several months
Mountain Journeys 131
in Tibet. He frequently lays stress upon the extraordinary height
of these regions and upon the cold and parching winds prevalent
there. The only observation that can be referred to the harmful
effect of altitude is the following; Turner was then at the foot of
Chumalari:
When we had dismounted at Terma, I felt a violent headache,
which urged me to throw myself upon a rug; .... I was in pain and
did not wish to talk. (Vol. I, p. 312.) ....
I attributed this headache, which gave me great pain, to the
change of climate. (P. 314.)
Captain Thomas Hardwicke -«"' in 1796 made a journey to
Srinagar in Little Tibet, during which he seems to have mounted
to fairly great heights; but he mentions no symptoms that one
can attribute to mountain sickness.
But with the celebrated journey of Moorcroft -1" who in 1312
crossed the Himalayas to reach Lake Manasarowar, begins a new
era, so to speak. After that, all the narratives of travellers will
contain clearly and often with details evidence of the sufferings
which altitude added to fatigue and cold.
He left May 26, but it was not until June 4 that one finds in
his journal the indication of a special distress:
Toward the end of this day (he says) I found that my respiration
quickened proportionately to the difficulties of the ascent, and I was
often compelled to stop and wait until the beating of my heart grew
calm. My companion had been suffering from this oppression for three
days, but I had not felt it at all until then. (P. 397.)
Moorcroft does not specify the height which he had then
reached; he only speaks of a village named Niti where he made
his camp then. After a few days, he wished from there to make
the ascent of the neighboring mountains:
On the morning of June 26, I set out. The ascent was very painful
because of the great difficulty in breathing; of five persons, only one
was capable of accompanying me .... I could not take more than
five or six steps without stopping to breathe .... Having suddenly
turned my back to the wind, I felt a sensation of fullness in my head,
with vertigo and threats of apoplexy; and so I quickly lay down on
the ground. Shortly afterwards, my panting slackened, the beating of
my heart became less violent, and I could rise. But in spite of pre-
cautions in walking, I was twice attacked by the same symptoms,
so that it seemed wise to me to give up ascending higher.
The imperious necessity of stopping to breathe every four or five
steps was felt only while I was climbing. When the violent action of
the heart was lessened by rest, the difficulty in breathing disappeared.
It did not appear during the descent, even when I ran; but several
132 Historical
times at our camp, just as I was going to sleep, I was aroused by this
sensation .... Although I experienced neither excessive cold nor
heat, my hands, my neck, and my face were red, the skin was sensi-
tive, and blood oozed from my lips, which had never before happened
to me. (P. 408.)
He refers repeatedly to the oppression which precedes sleep:
June 30, at sun-rise, the thermometer registered 46 °F I
awoke very early, and at once was seized with difficulty in breathing
and great oppression in the heart, symptoms which disappeared after
a few deep inspirations. As I was going to sleep again, the smothering
reappeared, and respiration became very uneasy; however, as soon as
the air had grown warm, this distress lessened. (P. 412.) ....
In the evening, although overcome by need of sleep, it was impos-
sible for me to fall asleep because of the smothering which came on
immediately, and which nothing but a few deep breaths could quiet.
(P. 415.)
July 3, Moorcroft reached Daba. The rest of his journey did
not expose him to mountain sickness, on the cause and nature of
which he did not venture any hypothesis.
In 1819, Moorcroft, in the company of Trebeck, began a long
expedition which was to end in 1825 with the death of the two
travellers. In the publication by Wilson -11 of the results of this
journey, I have found nothing relating to mountain sickness. In
telling of his crossing of the pass of Chang-La, the highest he
had yet crossed, Moorcroft complained only of terrible cold
(Vol. I, P. 428). At the pass of Parang-La, the altitude of which
he estimates as about 19,000 feet, he says only:
My horse was so unable to walk, before reaching the summit, that
I had to dismount and leave him to his fate. (Vol. II, p. 54.)
Three years after the first journey of Moorcroft, Fraser,'-'-
who accompanied the political agent sent to the army of General
Martindale, went up the banks of the Jumna in 1815. He crossed
the mountains from Jumnotree to Gangotree by very lofty passes,
the height of which he does not give.
On July 16 for the first time there appear in his narrative
symptoms which one may attribute to mountain sickness:
We were much annoyed by the coolies (he says) .... It was
very difficult to start them moving, and they sat down after a few
steps, although their burdens had been greatly lightened in prepara-
tion for the difficulties of the march. They told us that they were
attacked by the Seran, or poisonous air coming from the flowers
which covered the ground (primroses, polyanthus, heather) ; and
although their condition was perhaps partly due to drink and excesses,
Mountain Journeys 133
and although something must also be attributed to laziness, their
general appearance indicated something more. When they stopped,
they threw their burdens on the ground, and lay down sick; generally
they went to sleep immediately, and very few thought of eating first;
they told us that the next day's stage would be still harder. (P. 440.)
In fact, the next day, the sufferings increased:
It was exceedingly cold .... Many of the Mewatees and Goorkhas
were almost unable to go on, each one complaining of the bis, or
poisoned wind. I thought then that this supposed poison was nothing
but the effect of the rarefaction of the air due to our great altitude,
which makes it insufficient for our breathing; it cannot distend our
lungs; I have been brought to this belief by my own sensations. I
was obliged to make tremendous efforts to continue, and could hardly
find strength enough to walk. I experienced great respiratory oppres-
sion, as if I lacked air. We certainly could not have endured that
very long ....
At last we reached the summit of Bumsooroo-ke-Ghat, where
there was nothing but moss and lichens .... As soon as one of
those who complained of oppression lay down, he went to sleep, but
it did not seem wise to let him do so. Eating a few mouthfuls helped
a little, but nothing did much good, and no one was free from this
general weakness. This was the highest point of our journey. (P. 442.)
From there we had to execute a series of ascents and descents . . .
along a path which was very difficult and painful on account of the
snow and rolling stones; we were cruelly tormented by difficulty in
breathing, until we reached Chaiah-ke-Kanta. (P. 444.)
They were not at the end of their sufferings. The next day,
they had to make new ascents:
We were troubled by the difficulty of the terrain, the poor
condition of the road, and above all, by the artificial fatigue due to
the oppression which we all felt most severely. (P. 449.)
When we reached the high gorge of Bamsooroo, no one escaped
the baneful influence. It was strange to see those who had laughed
at their companions give themselves up, some to fatigue, others to
sickness, in spite of their efforts to hide it from the others. I think
that I escaped longer than anyone else; and yet, after passing this
gorge, a few steps upward seemed to me an impossible labor, and even
while I was passing over level places, my knees trembled under me,
and I experienced stomachic nausea. The symptoms produced are
quite varied; some persons suffer from violent headaches; others have
pain in the chest, with oppression; others have nausea and vomiting;
many are overwhelmed with drowsiness and fall asleep even while
they are walking.
But what proved that all of this was the effect of our great altitude
is that when we descended and reached the region of vegetation, all
these violent symptoms, all these sufferings diminished and disap-
peared. (P. 459.)
134 Historical
In 1816, 1817, and 1818, Captain Webb made vain attempts to
cross the Himalayas, and see again the sacred lake of Manasarowar;
the Tartars stopped him on the way. His observations were pub-
lished in an interesting article in the Quarterly Review; 213 some
of them interest us particularly:
Without raising the least doubt (says the editor who reviews
Webb's letters) in regard to the difficulty in breathing experienced by
M. Moorcroft in his ascent of Ghaut, we shall call attention to the
fact that higher ascents have often been made without any such effect,
which seems to indicate that these effects depend greatly upon the
state of the health. Captain Webb, however, confirms these claims, not
only by the evidence of his own sensations, but by that of the moun-
taineers themselves, who experience them as much as strangers do,
and he assures us that neither horses nor yaks are immune to them.
The natives call this illness Bis-kae-huwa, that is, poisoned air, and
attribute it to the emanations from certain flowers; it appears when
one is walking or when one is tired.
"Everyone", says our traveller, "complained of loss of appetite
for several days after our arrival at Nitee. As for me, I felt exactly
the sensations which precede an attack of fever, with great oppression
and exaggerated action of the heart and viscera. But one of those
who accompanied me suffered one of those attacks to which the resi-
dents of Boutan are subject, at the beginning of the season, and which
they consider as directly produced by the Bis-kee-huwa. He had gone
down to the river's edge at the close of day, and when he wished to
climb back up, he lost the use of his legs and even lost consciousness;
however, he still retained some feeling, but to me he looked like a
man struck by apoplexy. His extremities were cold, and after vainly
trying to revive him by friction and by the application of warm stones
on his hands and on the soles of his feet for several hours, I decided
to give him an emetic; a great quantity of foam was thrown up, and
in two or three days he recovered completely. I think that this secre-
tion of foam is an effect peculiar to the inhalation of toxic vapors.
(P. 420.)"
At about this same time the brothers Gerard began the cele-
brated series of journeys across the Himalayas.
In 1817 (August 27 to October 14) first journey of Captain
Alexandre Gerard, from Soobathoo to Rarung and return. He
was accompanied part of the way by Dr. Govan, of whom we shall
speak later. His account was published for the first time from
his travelling notes by Lloyd in 1841 214 (P. 191-267) . There is no
mention of mountain sickness in it.
The next year he set out again, this time accompanied by Dr.
J. G. Gerard, his brother. They went from Soobathoo to Shipke,
and returned to Soobathoo (September 22-November 22, 1818).
Mountain Journeys 135
From the simple notes which they published 2i5 I extract that
which concerns our subject:
October 2. Our tent is pitched at an altitude of 15,095 feet; on
the pass which separates Choara from Koonawur, there is only scanty
grass and a little moss .... During the night which we pass there we
all feel violent headaches, probably due to the rarefaction of the air,
but which the natives attribute to a toxic plant which grows abun-
dantly at great heights. (P. 366.)
October 7, crossing of the pass of Toongrung (13,729 feet), no
effect noted; October 12, the same, at 13,518 feet, at the pass which
separates Koonawur from Chinese land. October 16, camp at
14,900 feet, and October 18, ascent of a peak rising to 19,411 feet
(5915 meters) :
Violent headaches, hardly permitting us to make any efforts ....
The natives refused to go on .... To tell the truth, we ourselves
could no longer walk, so severe were our headaches, with general
weakness, and keen pains in the ears and chest .... The thermometer
did not fall below 22°F .... and yet because of the wind, my hands
were so numb that I had to rub them for a quarter of an hour
before being able to use them ....
The travellers who cross the pass of Gangtung consider it
extremely difficult: they are covered with garments to defend them
against the excessive cold, and they complain of terrible pains in the
head and ears; goats, sheep, and men often die there. (P. 377.)
October 24, the pass of Hungrung (14,837 feet); October 25,
the pass of Rooming (14,508 feet) ; no indication. November 22,
return to Soobathoo.
Alexandre Gerard soon set out on a new journey. This time,
he intended, if possible, to go up to the sources of the Setlej, one
of the tributaries of the Indus, which comes from Lake Manasaro-
war. The narrative of this journey forms the second volume of a
work published in London in 1840.216 It had already been pub-
lished in a shorter form in a scientific journal of Edinburgh, in
1826 and 1827.217 Both accounts are extremely chary of descrip-
tions and particularly of the physiological type. I quote from the
volume published in London.
The journey began June 6, 1821; Al. Gerard set out from the
land of Rol, at an altitude of 9000 to 10,000 feet. At the summit
of the pass of Shatool, at 15,555 feet (4738 meters) , where we shall
see that his brother was to suffer so greatly, he merely says:
June 9. We slept very little, because of headaches and difficulty
in breathing. (P. 15.)
136 Historical
At the pass of Boorendo:
June 16. As usually happens at these altitudes, we hardly slept
at all, worn out by headaches and an extreme difficulty in breathing.
(P. 37.)
At the pass of Keoobrung, 18,313 feet, he is a little more
explicit:
June 24. I felt great difficulty in breathing, and great weakness,
but no headache, although my followers suffered from the accelera-
tion of circulation noted by M. Moorcroft: the temperature was 46°.
August 30, he made the ascent of the pass of Manerung at the
enormous height of 18,612 feet (5671 meters) .
We were ascending the mountain very slowly; respiration was
difficult and we were almost exhausted at every step. The crest of
the pass was not visible, and we did not know when our troubles
would end: the road ascended at an angle of 30°
Our situation was different from anything we had experienced
before; it cannot be described. Long before we reached the summit,
our respiration became panting and oppressed, and we were forced
to sit down after a few steps; even then we could hardly inhale a
sufficient quantity of air. The slightest movement was accompanied
by weakness and mental prostration. We suffered thus for two miles;
the last half-mile was in perpetual snow. At the summit, the barom-
eter registered 15.300 inches, the thermometer 36 °F
Several of my followers could not cross the pass on account of
headaches. The length and the difficulty of the ascent, the rarity of
the atmosphere, the rigor of the climate, although it was summer,
make this pass dangerous to the sturdiest persons. (P. 240.)
September 29, he had reached Kotgurh, the end of the journey.
In the first volume of the work published by Lloyd, there is a
letter from Dr. Gerard, narrating his journey to the passes of
Shatool and Boorendo, with the purpose of determining the line
of perpetual snow. It is dated from Lake Charamace, at 13,800
feet, August 18, 1822.
At the height of 15,000 feet, the same symptoms attacked him
and his travelling companions:
I cannot describe the extreme fatigue which the last 500 feet
caused us. Distressed, sick, we could not use our arms to break off
a piece of stone with a blow of the hammer. Respiration was free,
but insufficient, our legs could hardly support us, and our faces were
drawn as if we were going to have the fever ....
All my people were in a wretched condition, I suffered from
headache, and everyone was complaining. (P. 308.)
It was August 9, they reached the summit of the pass of Boo-
rendo, at more than 15,500 feet, the thermometer standing at 37°:
Mountain Journeys 137
During the descent, I felt again the symptoms of headache, and
they did not leave me until after noon; I went out to get flowers, but
I was obliged to return to camp (12,800 feet). I awoke at daybreak,
unrefreshed by sleep. I had the same feeling of weakness and languor
as on the ascent, but not so bad. (P. 315) ....
My visit had removed my doubts on the phenomena of new snow
in the passes in July and August, and I had hardly any reason to
doubt the strange tales of the dwellers at the foot of the mountain
about the symptoms which sometimes attack travellers crossing it.
They say that the phenomena of drowsiness and weakness are much
more to be feared in the rainy season ....
The people who live at the foot of the mountain and who breathe
in a very much rarified air, or who are accustomed to climbing their
steep slopes suffer much less than those who inhabit a lower zone
in a denser atmosphere; but they know these effects very well, and
describe their sensations with ingenious and very interesting sim-
plicity ....
Between Koonawur (where the people seem born to live and die
in inaccessible regions) and the Indian slope of the mountains, we
travelled for a long time on the crests of mountains, at a positive
elevation of 16,000 feet: I met every day a crowd of people laden
with grain; they were walking slowly, stopping often to get their breath,
and they seemed to suffer from a uniform oppression. I have not
ascertained whether they are subject to an illness like the one I
experienced, and yet it must be so, and it is undeniable that above
a certain height, the effects of the rarified air upon the functions of
animal life are permanent and that neither habit nor constitution can
conquer them. (P. 320.) ....
Sandy and I, in our excursion to the peak 19,500 feet high,
although unable to take a dozen steps without being exhausted, and
finally being hardly able to move at all, nevertheless were better than
the villagers who accompanied us, and who live at the altitude of
12,000 feet. In the interior of the country, where the ground is very
high, the most dangerous symptoms appear while crossing the moun-
tains. Between Ladak and Yarkand, an intelligent servant of M.
Moorcroft told me of the fatal consequences of lack of precaution.
He says that the passage of the highest range should be made fasting,
and recommends frequent doses of an emetic during the journey. He
told me the story of a Russian merchant in good health, who was going
from Ladak to Lee to see M. Moorcroft, and who died while crossing
one of the passes because he ate a good meal before starting. Death, in
such a case, should be attributed to the drowsiness brought on by the
cold and the extreme rarity of the air which predisposes to inactivity
and leads the traveller to his last sleep. (P. 325.)
I took a little walk over the cliffs, but the sensation of fullness
in my head forced me to return. Since I arrived here, I have been
more or less affected by headaches, particularly violent at night; the
pain was not like that of ordinary headaches, but as if an over-
whelming weight (a dead weight) was attached to all sides of the
head, pushing it in different directions. Tea relieved me, but only for
a short time. (P. 325.)
138 Historical
I suffered greatly at night from headache and from a sort of
drowsiness, such as occurs in drunkenness. I have never felt such
evident proof of the existence of an agency dangerous to the principles
of animal life, and although I suffered much more in the pass of
Boorendo, in 1818, the illness did not last day after day, as it did here.
All my servants were also affected, some by nausea, others by head-
ache; they were not all equally affected, but we could judge that that
was only a matter of chance; we should merely say that the natural
conditions of energy and action are not always the same ....
The extremes of the barometer here were from 17.055 inches to
17.160 inches; those of the thermometer from 41.5°F. to 53°; which
gives the pass of Shadool an elevation of 15,500 feet. (P. 326.)
Captain Al. Gerard, moreover, has left us in a special chapter
of a posthumous work,218 a summary of the data which he observed
in his numerous excursions:
On lofty mountains, a depression of spirits and a weakness of
body, accompanied by cruel headaches, fullness in the brain, oppres-
sion of the chest, difficulty in breathing, with pain in the ears from
time to time, affect everyone more or less. All these symptoms result
from the rarefaction of the air, and of this I have had numerous
proofs, having visited thirty-seven places at different times, between
14,000 and 19,400 feet, and thirteen times my camp was pitched
above 15,000 feet. It should be noted that the people of Koonawur
and the Tartars estimate the altitude of the passes by the difficulty
in breathing which they experience when they make the ascents of
them.
However it should be noted that the difficulty in breathing does
not affect everyone equally or at the same time; it certainly depends
largely on the state of health. When I was not well, I suffered
from headache at 13,000 feet, whereas in good health I felt no effects
at 16,000 feet. At Boorendo (15,000 feet) I was very cold, and expe-
rienced, even when resting, a greater suffocation than ever happened
to me at 19,000 feet, while I was walking.
Any fatigue, but especially the ascent of hills, increases these
symptoms: from 17,000 to 19,000 feet, the headaches are constant,
and no one can take more than a half-dozen steps without resting.
When one camps above 16,000 feet (4875 meters), the difficulty
in breathing is really terrible, and often for whole hours I thought
I was going to suffocate.
Persons who have not made such journeys can hardly imagine
how much time it takes to cover a distance of twelve or fourteen
miles in lofty places. I have gone thirty-four miles on foot in lands
which would be called mountainous by those who do not know the
difficult parts of Koonawur, with more ease and in less time than I
could walk twelve miles in these lofty regions. An ascent of 5000 or
6000 feet is not rare, and when the elevation is more than 14,000
feet, every mile, even when the road is good, requires at least twice
as much time as at the height of 7000 to 8000 feet. The prostration
of mind and body experienced on lofty mountains affects everyone
Mountain Journeys 139
more or less, and one of my friends was more wearied by an ascent
and a descent of 5000 feet, in a total walk of nine miles on lofty
ground than in going from Nahun to Soobathoo, which is 45 miles.
(P. 57-59.)
The observations of Captain Hodgson who, in 1817, went to the
sources of the Ganges and one of its principal tributaries, the
Jumna, deserve to be quoted for the same reason: 219
We experienced a great difficulty in breathing and that peculiar
sensation, constant at great elevations where there is no verdure,
which I have never felt anywhere as severely as on fields of snow,
even when I ascended higher ....
The mercury stood at 18.854 inches, at a temperature of 53 °F. so
that the altitude was 12,914 feet (3935 meters). (P. 111.)
It was May 30; the travellers had reached the source of the
Ganges.
These countries were visited ten years afterwards by Captain
Johnson, whose account-" gives data identical with those of his
predecessors. Moreover, the dangerous effect of lofty places is
well known to the people of the country.
In fact, July 1 and 2, 1827, Johnson made the ascent of the
peak of Tazigand or Pendjeoul:
The natives, learning of M. Johnson's plan, tried in vain to
persuade him to abandon it by exaggerated accounts of the innumer-
able difficulties which it presented and of the dangers of the bis or
poisoned wind which blows over the snow. (P. 160.)
Moreover, a fact which deserves mention and of which we shall
subsequently find many examples, the people dwelling in the
country suffer much more than the Europeans:
On July 2, Captain Johnson occupied the same ground as that
where Dr. Gerard had made his barometric calculations at a height
of 19,411 feet (5915 meters) above sea level ....
The natives who had guided him there found breathing very
difficult; they stretched out on the snow, holding their necks in both
hands, and the Sepoy nassir, who was the only one to reach the
greatest height, complained a great deal also. It is surprising that
our compatriots felt no distress. They occasionally experienced diffi-
culty in breathing; but they had blisters on the hands and feet and
momentary blindness from the glare on the show. (P. 162.)
The French traveller Jacquemont seems to disagree with the
statements of all his predecessors. At least, he declares that he
felt no symptoms at heights often equal or superior to those at
which the English travellers suffered so greatly. This difference
140 Historical
made such an impression on him that he reported -1 it to the pro-
fessors of the Museum of Natural History, and tried to explain it:
Kurnaul, February 1, 1831
Several English travellers have crossed the pass of Bouroune
(about 15,000 feet), and all complain of the headaches and nausea
they experienced there. I have gone through much higher places,
because I camped three times above 16,000 feet, and on my way to
Beckhur, I had to cross passes at an altitude of more than 18,000
feet. I have never felt any of the painful symptoms of which all
travellers on lofty mountains complain, and I have never observed
them in even one of the numerous companions of my excursions. I
lived seven months in the Himalayas; I have ascended from their feet
to their summits; at the time of my journey to Beckhur, four times I
ascended to an altitude of 6000 meters, and for almost two months I
almost never went below 3000 meters; then I camped at 4000 meters
after a stay at 5000 meters. When the ascent is so gradual, the lungs
easily become accustomed to working freely in an atmosphere which
gradually becomes more rarified. It is a very considerable change of
level in a short time that affects them and produces the oppression
mentioned by Saussure and all who ascended Mont Blanc after him,
long before they reached the summit. (P. 53.)
The interesting notes he left, which were published after his
death,2-2 contain very interesting observations on this subject, to
which he had given particular attention:
May 16, 1830, I reached an altitude of 3927 meters .... This
was the first time I had ascended to so great a height; it exceeds that
at which the effects of the rarefaction of the air begin to be felt
painfully in the Alps. I did not feel them at all; I was no more out
of breath than I should have been at the lowest level, if I climbed
equal grades with the same speed.
I saw no real symptoms in any of the people who followed me;
no panting, nor drowsiness, nor nausea.
It seems to me that in the temperate climates, on parallels like
those of the Alps and the Pyrenees, one feels them sooner than on
mountains nearer the equator. If this statement stands out uniformly
in the testimony of travellers, it is hard to explain. The effect, if it
depends solely on the atmospheric rarefaction, should be the same at
the same altitude in all the regions of the earth, or even greater in
the tropical countries where the temperature rarities the air more
at the same elevation. (P. 101.)
Jacquemont refers repeatedly to this harmlessness of the heights
of the Himalayas compared to the bad effects in the Alps; in the
following passage he even offers an explanation of it which has
some foundation:
I crossed the pass of Rounang, at an elevation of more than 4267
meters, three times, on horseback.
Mountain Journeys 111
This elevation is higher than that at which travellers claim to
have begun to feel the effects of the rarefaction of the air in the
Alps and the Pyrenees. I did not feel them at all. Perhaps the breath-
lessness from which Saussure and his guides and all those who
followed his steps on Mont Blanc since then suffered was only the
result of a long and difficult march on exceedingly steep slopes.
Perhaps if one could be carried from Chamounix to the summit of
Mont Blanc, one would escape the illness which is generally attributed
to the rarefaction of the air at its crest. The Gerard brothers, who are
undeniably the foremost travellers in Alpine regions, constantly com-
plain of excessive fatigue and violent headaches on all the passes tney
crossed, between 4572 and 5791 meters; and this painful condition
continued as long as they remained at these heights, where they
camped several times. From that fact it would seem that this illness
was not merely the passing effect of fatigue caused by a long climb,
but really an effect of the atmospheric condition ....
The elevation of Mont Blanc is 3780 meters above Chamounix,
which is only about 1036 meters above sea level. The ascent is made
in thirty hours. There is an enormous change in atmospheric pressure
in which one is immersed, and in a very short time. So sudden a
transition, independent of the fatigue involved in making it, can
definitely affect the respiratory organs. Here, on the contrary, for
more than three months, I have been living at an elevation on the
average 1829 meters above sea level, and for the last month, at 2743
meters, an altitude at which I feel none of the effects of the rarefaction
of the air. When I ascend to an absolute elevation of 4572 meters, I
pass through a vertical difference of only 1829 meters, half of that
which exists between Mont Blanc and Chamounix, and I have no
sensation which I can refer to a respiratory disturbance. Finally, the
proof that the annoying symptoms felt by travellers on the summit
of the Alps or on the passes of the Himalayas would vanish in time,
and that their lungs would find enough oxygen in an air which has
lost half its density, is the existence of the farm of Antisana in the
Andes, which M. von Humboldt told us about, at an elevation of about
4114 meters, where a family lives, plows, and works. There is no
doubt that the lake of Manasarowar exceeds this height by 305 to 457 22;>
meters, and yet there are dwellings on its banks, and pilgrims
go round it in a seven day journey. M. Gerard himself proves very
satisfactorily that a considerable portion of the high country, in
which the Kanaweri merchants travel in going from Shipki or
Skialkur to Garou (Gortope), is above 4877 meters in elevation, and
yet these merchants do not complain there of symptoms by which
we see them attacked when crossing passes often at a lower altitude;
whence I conclude that in the latter case it is from the fatigue of
the journey that they suffer, laden as they are, whereas in the lofty
plains of Chinese Tartary, they walk empty-handed on an almost
level road.
I myself have felt at an elevation of 4000 meters some of the symp-
toms in question, that is, fatigue and headache. But I have hardly ever
mounted to this height without being exposed to a furious wind, and
whatever precaution I took against its cold, I was always chilled, and
142 - Historical
this acting first in me upon the digestive tract, caused a disturbance
in the digestion, of which the headaches were evidently the conse-
quence. (P. 259.)
The following observations corroborate the first explanation
given by Jacquemont:
August 11, 1830, I reached the altitude of 5486 meters on the pass
of Gantong; at the summit, I felt absolutely no difficulty in breathing,
as long as I remained motionless, carried by my horse, but when I
tried to walk on an almost level road, fatigue and panting appeared
promptly. And yet I saw my servants, to reach the summit of the
pass, walk several hundred steps on very moderate slopes of snow,
without stopping to get their breath; only one was sick. (P. 288.) ....
August 16, at the pass of Kioubrong (5581 meters), the same
immunity; I ascended there rapidly over a very gentle slope, and
walked quickly for more than an hour, without feeling any special
lassitude caused by the elevation, no pains of the head or ears, no
tendency to sleepiness, in a word, nothing particular, perhaps, but
a slight panting; and in fact, after a few minutes rest, my pulse rate
was 82. (P. 297.)
The limit of perpetual snow in this region of the Himalayas
is hardly below 6000 meters, according to Jacquemont.
Finally, Jacquemont wished to fix clearly the conditions of the
problem by a personal experience:
I had ridden on horseback to Kioubrongghauti, and since the
experiment which I had made there of walking rapidly for an hour
in a place with an altitude of 5600 meters, after reaching it without
any fatigue, left me without doubt as to the cause of the strange
symptoms experienced by travellers who ascend to the summit of
Mont Blanc, I wished to climb the pass of Gantong on foot, to see
whether the walk, which was prolonged but prolonged moderately for
only five hours and very slowly, with numerous intervals of rest, on
slopes which are really very steep, but whose vertical height did not
exceed 1000 meters, would reduce me to the state of exhaustion descri-
bed by M. Gerard as the immediate consequence of the slightest
movement, as soon as one reaches the absolute elevation of 4572
meters. That was just the level of my starting point.
Stimulated at the beginning of my walk by the morning chill,
sustained beside by the freshness of the wind, preoccupied by interest
in the objects which I saw at every step, often stopped by them, and
taking care after walking three hours to eat a light lunch to ward
off any feeling of hunger, which, I have found, always produces in
me in lofty places an extreme weakness and headaches, I arrived
without weariness, and almost without perceiving it, at the summit
of the pass of Gantong, at an elevation of 5576 meters. (P. 302.)
But if Victor Jacquemont was almost free from any acute
symptom, and did not see any appearing in his travelling com-
Mountain Journeys 143
panions and his beasts of burden, it is far from being true that
all travellers have enjoyed the same immunity.
In fact, in the annals of Berghaus, for March, 1832, we find
the following quotation, relating to a passage of the Himalayas
on the border of Sutlej; the name of the traveller is not mentioned:
At an elevation of 15,000 feet, respiration becomes difficult; the
traveller feels great lassitude, vertigo, headaches and unquenchable
thirst. It is impossible to describe the sensations produced by extreme
rarefaction of the air; one constantly feels as if he were smothering;
respiration accelerates in a very painful manner, the elasticity of the
skin diminishes. The highest "* point of the pass is at an elevation
of 16,500 feet. (P. 547.)
Moreover, Lieutenant J. Wood,225 who made a journey to the
sources of the Oxus in 1836, 1837, and 1838, gives numerous and
interesting details on this subject.
February 20, the expedition reached the plateau of Pamir,
the altitude of which is 15,600 feet, the mountains surrounding it
rising 3000 or 4000 feet higher; the party was at the sources of the
Oxus, on the shore of a frozen lake:
We began to break the ice to sound the depth of the lake. The
ice was 2V2 feet thick, and because of the great rarity of the air, a
few strokes with the picks exhausted us so much that we had to lie
down on the snow to get our breath. (P. 360.) ....
Fifty steps at full speed set us to panting. In fact, exercise
brought on pain in the lungs and a general exhaustion which did not
improve for several hours.
Some of us suffered from vertigo and headaches, but except for
these various phenomena, I felt nothing and saw nothing in the others
which resembled the sufferings experienced by travellers in the
ascent of Mont Blanc. In the latter case, the transition from dense air
to rarified air is so sudden that the circulation does not have time to
adapt itself to the difference in pressure, so its speed increases in some
of the most sensitive organs of the body. The ascent of Pamir, on the
contrary, was so gradual that it required "extrinsic" circumstances to
remind us of the considerable altitude which we had reached.
The effects of the great elevation had, however, been proved to
me some time before in a manner for which I had not been prepared.
One evening, in Badakhshan, as I was sitting reading by the fire, I
had the idea of feeling my pulse, and its rapid and wild beating
aroused my attention. I imagined that I had been attacked by a
violent fever, and I used the precautionary measures which Dr. Lord
had prescribed when he left. The next day, my pulse was as rapid
as on the day before, and yet I felt in excellent health. I thought then
of examining the pulse of my companions, and to my great surprise
I found that theirs were more rapid than mine. The cause of this
increase in circulatory activity was evident to me at once; and when
144 Historical
we next went toward Wakhan, I counted the pulse of my companions
every time I recorded the boiling point of water.
The changes in the pulse thus form a sort of living barometer,
by means of which a man accustomed to examining himself can,
at great altitudes, estimate roughly the elevation.
On Pamir, the pulse rate gave the following figures:
Myself 110 Scotland fat
Gholam Hussein, Munshi 124 Jasulmeere fat
Omer-Allah, muleteer 112 Afghanistan thin
Gaffer, servant 114 Peshawuree thin
Dowd, servant 124 Kabul robust
The elevation of the snow line in this region is above 17,000 feet
(5180 meters). (P. 352.)
Lieutenant Wood was accompanied for part of his journey by
Al. Burnes, an envoy to Caboul. October 19, 1837, two others of
their companions, Lieutenant Leech and Dr. Lord, went to recon-
noiter and cross a pass of Hindu-Koush, going to Caboul. The
pass is about 15,000 feet high; the snows would soon render it
impassable; the ascent was easy. However, says Burnes:--'6
The horses were in a very pitiful condition, and they had to
dismount and walk. No one had any symptoms, but the natives
informed them that they themselves were frequently attacked at this
point by vertigo, faintness, and vomiting. (P. 152.)
Some years later, a French traveller, who travelled over not
the Himalayas, but the much less lofty regions of Upper Tartary,
made a pitiful story of his sufferings. It is true that one must be
on his guard against the statements of Father Hue,-'-7 whose credu-
lous simplicity is almost boundless. Nevertheless, the vivid pic-
ture which he has left us of the sensations experienced during
the passage over Bourhan-Bota, a mountain the height of which
he does not give, and which seems to be situated about longitude
95° E. and latitude 40° N., deserves to be reproduced here. The
day of the ascent is not specified, nor is the temperature of the
air:
We prepared to cross Bourhan-Bota, a mountain famous for the
pestilential vapors in which, they say, it is continually enveloped ....
Soon the horses refuse to carry their riders, and everyone proceeds
on foot slowly. Gradually all faces grow pale, nausea comes on, and
legs refuse to function; one lies down on the ground, then gets up
and makes a few steps more; then one lies down again, and this is
the miserable fashion in which one climbs this famous Bourhan-Bota.
Good heavens! What wretchedness! One feels his strength broken,
his head whirls, all members seem to be disjointed, one feels illness
exactly like seasickness, and in spite of that, one must save enough
Mountain Journeys 145
energy, not only to drag himself along, but also to beat energetically
the animals which constantly lie down and refuse to go on. A part of
the group, as a matter of prudence, stopped half-way, in a depression
where the pestilential vapors were less thick, they said; the rest, also
out of prudence, exerted all their powers to get through with it and
not die from asphyxia, in the midst of this air laden with carbonic
acid. (P. 256.)
The travellers whose accounts I shall now mention agree
much better with what the Gerard brothers said than with the
extreme statements of Jacquemont and Father Hue.
July 14, 1845, Hoffmeister -L'8 reached the highest point of his
journey, the pass of Lama-Kaga (Thibet) at the elevation of
15,355 English feet; the temperature was — 50° Reaumur; the snow
was falling:
About an hour and a hslf passed before our first coolies arrived
with our baggage. They were in a very sorry state, and were suffering,
as well as our interpreter M. Brown, from headaches which they
described as unbearable. Loss of strength, pains, and nausea are the
symptoms of this illness which they call here Bies (poison) or Mun-
dara. It attacks travellers thus at the line of perpetual snow. In the
coolies it appeared halfway up the pass. As a remedy against it they
use a sort of paste made of little sour apricots and their seeds. (P.
242.)
In the account of Dr. Th. Thomson,-'2'' it was not only the coolies,
but the European traveller himself, who was affected by the
altitude.
September 6, 1847, Thomson and his attendants camped at an
altitude of 14,800 feet, and on the 7th, they ascended to 17,000
feet (5180 meters):
The whole day long I had never been free of a violent headache,
evidently caused by the great elevation. Rest relieved it, but it
reappeared at the slightest movement. It lasted all evening, as long
as I was awake, and I still had it on the morning of the 8th, when I
got up at daybreak to prepare for the journey ....
The ascent next day was extremely steep and difficult. The act
of raising one's body was very tiring, and the last few hundred yards
were covered only after several pauses .... I reached the summit
of the pass of Parang at a quarter of eight in the morning; I was .
at an elevation of 18,500 feet (5640 meters) ; the temperature was 28°
.... the snow was frozen .... the wind blew violently .... We
descended without fatigue .... (P. 135.)
After living a year in these lofty regions, Dr. Thomson recon-
noitered towards the north, as far as the celebrated pass of Kara-
korum, at a height of 18,604 feet (5670 meters) . There again, his
146 Historical
symptoms reappeared, or to speak more exactly, they became so
intense that he was compelled to make special mention of them:
August 19, 1848. During these three days of ascent, I suffered
greatly from the effects of the rarefaction of the air, being constantly
tormented by a painful headache which the least exercise aggravated
.... The temperature of the air was 50 °F.
The botanist Dalton Hooker is still more explicit.-50
At the height of 16,000 feet, while ascending the pass of Kang-
lachem, December 2, 1848, in eastern Nepal, Hooker experienced
difficulty in breathing, great lassitude, vertigo and headache. (Vol.
I, p. 247.)
Some days afterwards, on the mountain of Nango, at a height of
15,000 feet:
I found it quite impossible to remain composed because of the
increase of the pains in my forehead, lassitude, and oppression.
(P. 252.)
July 25, 1849, crossing of the pass of Kongra-Lama (15,741
feet) :
After two hours, I was chilled and stiff, and was suffering from
headache and vertigo due to the elevation. (Vol. II, p. 82.)
September 18, ascent of the pass of Sebolah (17,517 feet) :
I took the pulse rate of eight persons after a rest of two hours;
it varied from 80 to 112, mine being 104. As usual at these altitudes,
everyone was suffering with vertigo and headaches. (P. 142.)
October 15, night passed at an elevation of 17,000 feet:
My coolies were in good health; but those of Campbell were in a
very sad condition of pain and fatigue; their faces were swollen and
their pulses rapid; some were practically insensible with symptoms of
weak cerebral pressure; the latter were especially the Ghorkas
(natives of Nepal). I have never experienced bleeding from the nose,
ears, lips, or eyes, and have never seen such symptoms in my com-
panions on such occasions; nor have I met any recent traveller who
has experienced them. Dr. Thomson has noted this too, and when
we were together in Switzerland, we learned from A. Balmat, Fr.
Cartet, and other guides of experience on Mont Blanc that they had
never witnessed these symptoms, nor the darkening of the skin, so
frequently mentioned by Alpine travellers. (P. 160.) ....
October 17. It is quite surprising to see that Turner nowhere
alludes to difficulty in breathing, and speaks only in one place of
headache, even at this great elevation. That is probably because he
was always on horseback. When I was riding, I never felt any dis-
turbance in my breathing, my head, or my stomach, even at 18,300
feet (5580 meters). (P. 167.)
We see that it is while they are crossing passes that travellers
feel symptoms; ascents, properly so-called, of isolated mountains
Mountain Journeys 147
are, in fact, extremely rare. However here is one, in which
Captain Robertson,'-31 in October, 1851, reached the summit of
Sumeru-Parbut, at a height which he estimates as about 20,000
feet (6100 meters). The preceding night was passed at nearly
4000 meters:
The next morning, we left our tent at ten minutes past eight,
and at thirty-five minutes past one reached a sloping glacier. At this
point, vision and respiration became very painful for Lieutenant
Sandilands and several of our guides ....
Sandilands reached a spot half an hour's distance from the sum-
mit, where he was so affected by the rarefaction of the air that it was
physically impossible for him to go any further; he therefore turned
back, with the only Rajput who had followed him thus far, the others
having abandoned him long before; my Brahmin, a handsome young
man of strong constitution, who came with me to the summit, appar-
ently felt no effects, but when we reached our tent again, he could
eat nothing. As for me, my eyes were painful, and my respiration
and my vital force were affected, but yet I had enough energy and
physical force left to climb still higher. On my return to my tent,
my appetite was not affected at all, and I ate a hearty supper.
But the most interesting accounts I have found in my reading
are certainly those published by Mistress Hervey. And that is
easy to understand; a simple tourist, not heeding politics or geog-
raphy, or science, she gives special attention to everything relating
to her health and the little incidents of her journey, which she
tells obligingly in all their details. Besides, since she has rather a
weak constitution, she seems to be easily affected at rather low
levels.
So it is to mountain sickness that we must attribute part of the
following symptoms, although the elevation is very moderate:
June 25. We halted (after crossing the pass of Rotung (11,000
feet, 3350 meters) in Lahoul) .... Captain H. came to say good
evening to me in my tenf about nine o'clock, and noticed that I was
very pale, and that my face and hands were cold and clammy. I was
then very sick; I was delirious; I was nauseated, my hands and feet
were icy cold. Convulsions came on and I frothed at the mouth. I
stretched myself on the ground, and remained there in great distress;
they gave me two doses of Luce water, and put my feet in water
which, though it was boiling hot, could hardly restore the circulation.
Yesterday I was sick all day and unable to get up; my pulse rate was
not less than 108. I am better this morning, but my pulse rate is
still very high, although less irregular.
Captain H. declares that this sudden illness is due to the rarity
of the air of the pass .... If I am already affected thus, what will
happen at 16,000 or 17,000 feet? (Vol. I, p. 117.)
148 Historical
But if doubt is possible in this case, it certainly is not in the
following quotations. July 6, crossing of the pass of Bara-Lacha;
Mistress Hervey was very ill:
I had severe pains in my legs, and felt extreme lassitude, long
before reaching the summit of the pass; but I made a violent effort
to overcome these sensations, and succeeded in riding to the summit.
As soon as we dismounted, a terrible, splitting headache attacked me.
Before reaching Yunnumscutschoo, I had suffered from nausea and
felt as if my head were going to split. The principal sensations were
a very painful and very intense throbbing in my temples, violent
nausea, pains in my legs, and a lassitude amounting to prostration.
No one else was sick in the camp, except Ghaussie, who had a bad
headache.
I could not get to sleep at night before one or two o'clock, and
was awakened by the throbbing of my heart, so violent that I felt
serious fears about it. My pulse was galloping, my head was burning
and my temples throbbed, and I was wretchedly nauseated. We did
not set out until late the next morning, and if I had not felt better,
we could not have moved at all. Captain H. told me that he had had
a bad headache during the night, that he had felt tired and ill, but
that nevertheless he had not suffered as much this time as the last
time he had crossed the pass, for then he had had the same sensations
as I ... .
The pass of Bara-Lacha is, I think, between 16,000 and 17,000
feet above sea level, according to Captain Cunningham. (Vol. I, p.
133.)
Mistress Hervey then relates that the natives of the country
attribute all these symptoms to the effect of a poisonous plant;
but this time, the plant is a kind of moss. We shall quote this
passage in Chapter III.
The next day, the road, which still ran along at great heights,
several times forced the travellers to ascend small hills:
As we ascended (says Mrs. Hervey) I noticed a great many
poisonous mosses, two or three species of which were growing on bare
rocks.
I had a terrible headache, and was shivering with a return of
the terrible "pass sickness" or, as the natives say, from being
"boottee luggeea", that is, affected by the plants.
Tomorrow we shall ascend the Long-Illachee Joth (or pass),
and descend it, which promises to me a fine day of boottee. (Vol. I,
p. 139.)
And in fact, when she reached Rokchin (Ladak) the next day,
Mistress Hervey declared that she was so sick and so weak that
she could not write. July 9, after a night's rest, she could hardly
write and had to remain lying down. Two of her servants were
Mountain Journeys 149
very sick. Captain H. suffered during the night from a violent
headache. (P. 142.)
July 11, passage of a place the height of which Mistress Hervey
estimates at about 17,000 feet:
I had a worse headache than usual with a terrible oppression of
the chest. It is true that since the crossing of the pass of Bara-Lacha,
I have constantly suffered greatly from the effects of the rarity of the
air; a constant headache, and, especially during the night, a painful
pulmonary discomfort, and a very annoying acceleration of the move-
ments of the heart. I had hardly an hour of continuous sleep; I had
to sit down on my bed, as I could not breathe when I was lying down.
These lofty regions do not suit my lungs. (P. 152.)
The following night, camp at 14,800 feet on the banks of Lake
Choomoreeree:
I am now afraid of the night, because, far from sleeping, I suffer
terribly. Yesterday, it was really very painful; besides a cruel head-
ache, I suffered from great oppression in the chest, and my heart went
at a railroad pace, when I moved even an inch in my bed. (P. 153.)
These sufferings were so great that they decided her to change
her route a little, to avoid great heights (P. 162) . And yet, July 16,
when she reached the foot of the pass of Tunglund, she wrote:
We saw much poisonous bootie today on the road. I was wretch-
edly sick all night. About eleven o'clock in the evening, the
respiratory oppression and the suffocation became so unendurable that
I had to sit up on my bed to get my breath a little. (P. 169.)
The next day, ascent of the pass (between 16,000 and 17,000
feet) :
The odious moss of which I have spoken so often covered the
pass, and long before I reached the summit, I had a most violent
headache. But I had no nausea, perhaps because the pass is very easy.
(P. 171.)
July 19 of the following year, in spite of her continued resi-
dence in the lofty regions of Little Thibet, Mistress Hervey was
not acclimated, for, as she crossed the pass of Brarmoorj in Wurd-
wun (from 15,000 to 16,000 feet), she said:
I suffered from an absolutely unendurable headache, which kept
constantly increasing; but I did not have the nausea which I always
felt on all the passes of Ladak. (Vol. II, p. 298.)
And August 5, 1851, while crossing the pass of Hannoo (be-
tween 15,500 and 16,000 feet), in Ladak, a pass of rather easy
access, she suffered horribly; it is true that she was already ill.
She said the next day:
150 Historical
I have crossed many passes, but until today I had never expe-
rienced the terrible sensations which almost made me crazy before I
was halfway and long after I had left the great heights. My sufferings
might have been aggravated by my illness, but in any case, they were
crushing. I lay down on the ground at Dora, more dead than alive,
and my servants made me a tent of blankets. I was in such a state of
prostration that not only was I unable to rise, but I could not bear
to be carried in a "dhoolie" .... A violent headache, unbearable
nausea, hasty palpitations, and the inability to breathe deeply, such
were the symptoms of the well known bootie, which attacked me more
severely than ever before I reached the summit of the pass. I am sure
that if I had stirred about for a quarter of an hour during these
horrible sensations, some blood vessel would have broken and I should
have died on the spot. Just speaking was a painful exercise, which
brought on copious hemoptysis and increased my pulse rate far
beyond 100 per minute. I was terribly nauseated, and the exhausting
power of this distress can be compared only with the nausea of sea-
sickness. I was also very wretched and my sufferings were intense
yesterday. Even today I cannot breathe without pain, and my heart
beats violently and irregularly; I have not yet forgotten the rarified
atmosphere of the pass of Rannoo.
As they were carrying me yesterday about a half-mile from the
summit, Ghaussie called my attention to one of my servants, who
was lying unconscious on the snow. They woke him easily, but he
refused to move, saying that his head "was going to split in two."
After a slight struggle between humanity and strongly rooted prej-
udices, for the sick man was a sweeper, the lowest class of servants,
I sent him my own pony to carry him; if he had been left there, he
would certainly have died during the night.
While I am speaking of the illness on this pass as a case of
bCwtie, I must confess that I did not see a single plant of the particular
kind of moss, which, in the passes of Ladak and Lahoul, are considered
as poisoning the wind and causing the painful illness which I have
described.
One of my servants from Cashmere was the only other person
among my attendants to be affected; distress in high altitudes is
therefore not a rule without exception. (Vol. II, p. 367-370.)
And the next day, as she set out from Scheerebookhchun, she
wrote:
I shall travel by moonlight, for I have been so sick all day that
I have had very little desire to move. If I let myself be governed by
the painful sensations which have tried me so much, I should not
start now, but that might be impolitic. In my opinion there is
nothing like exercise to overcome our little bodily and mental troubles.
I must practice what I preach, and ride horseback this morning,
sending my dhoolie on ahead. (P. 378.)
She set out at sunrise, and went on horseback to Kulatsey.
I was then so sick and so exhausted that, not finding my dhoolie
there, I lay down on my shawl on the ground for several hours. At
Mountain Journeys 151
last, towards evening, another dhoolie was ready, and I could get into it
.... I have not recovered from the effects of the rarified air on the
pass of Hannoo. My heart beats violently and irregularly, and when
I breathe, I have severe pains in my chest. My distaste for nourish-
ment is so great that I can hardly touch any food all day long.
(P. 378.)
August 14, crossing a sort of a pass, near Ghia:
I have suffered from a very painful headache, but have felt no
nausea, although I recognized my old enemy, the bootie, the fatal
moss of Ladak-Oojar. When I walked fifty steps to pluck a flower,
the throbbing of my heart increased terribly, and repeated doses of
digitalis have not quieted its hasty and violent beating. I do not
know any sensation that is more alarming and more painful than this
exaggerated action of the heart. None of my servants felt any ill
effects ....
I reached Zurra at sunrise. I am completely prostrated by my
splitting headache, although I have escaped nausea, and that is the
only consolation I have in my sufferings. (P. 397.)
August 18, camp at Choomoreeree, at a height of 14,794 feet
(4510 meters) :
I passed a miserable night, and this morning I am sick and
exhausted. I had to remain thus half the night, absolutely incapable
or breathing in a horizontal position; my heart beat violently with
terrifying palpitations. I was really afraid of dying in the dark ....
In the evening, we camped at an elevation of nearly 15,000 feet.
I have the greatest difficulty in breathing, my chest seems loaded with
an enormous weight which oppresses me painfully. These distressing
sensations increase at nightfall. (Vol. Ill, p. 13.)
August 20, camp at the foot of the pass of Parung, at about
17,000 feet (5180 meters) :
A terrible height in which to pass the night under a tent, when
one suffers from the rarity of the air as I do. Oppression in the chest,
extreme difficulty of respiration, frequent spitting of blood have left
me no rest during the last sixteen hours .... The cold is intense ....
At daybreak, I feel better, although I cannot breathe freely, and
although the slightest movement distresses me .... My head has
almost recovered, and since my courage has returned, I have decided
to cross the pass .... To go on horseback is impossible, to walk ?.s
impossible too; I am riding a yak. (P. 19.)
Strange thing, that although this pass is the highest our travel-
ling lady has crossed, she has little trouble there; no nausea, only
a slight headache (P. 26). Moorcroft estimates it as at 19,000 feet
(5790 meters), and Mistress Hervey goes to 20,000 feet (6095
meters). She is naturally amazed at this result:
152 Historical
It is curious (she says) to note the different effects of the
different passes. Although the painful sensations observed undeniably
result from the rarity of the air, it is certain that the illness is not
proportional to the elevation. On the passes of Bara Lacha and
Hannoo, I was wretchedly sick, beyond all description, and on the
pass of Parung, 3000 or 4000 feet higher, I had no nausea, hardly a
headache. I had difficulty in breathing, but that seems to me a
secondary matter.
I am far from being able to give a satisfactory reason for this
difference. I have crossed so many passes that I have had many
opportunities to note how little relation there is between the "pass
sickness" and the elevation, of course, beyond 13,000 or 14,000 feet.
The "Bischk-ke-B66ttie", or poisonous plant, covered the ground many
miles around Tatung. (P. 33.)
The journeys of Captain Oliver -33 in the Himalayas also offer
an account of impressions connected with our topic. In July, 1859,
he crossed the pass of Roopung, at about 15,500 feet (4720 meters) :
We camped at the lower line of perpetual snow, at 14,000 feet
above sea level. It was very cold ....
We set out the next morning over the snow .... The summit of
the pass appeared in a wild and desolate scene. But I heeded it little,
being occupied with myself, for the rarefaction of the air was acting
upon me. I suffered from a painful shortness of breath, and soon I
had to stop every two or three steps. The snow was soft, which made
walking still more difficult .... I finally reached the last slope, a
bank of snow 50 feet high and very steep .... But at the moment
I was so completely exhausted that I was quite unable to cross it
without assistance. However, after a short halt, I made a desperate
effort, and somehow or other I reached the summit, where I stretched
myself out on the ground, absolutely exhausted. (P. 84.) ....
This pass is much frequented by the Tartars who bring borax
and wool to the Indian markets. They suffer greatly, however, from
the rarefaction of the air, but attribute its symptoms to a poisonous
plant, a fabulous plant, which, according to them, grows at great
elevations.
They are also subject to violent attacks of colic in the passes ....
One of my Sikhs was attacked by it; he lay down on the summit,
groaning, and declaring that he was going to die; thirty drops of
laudanum restored him. (P. 85.)
The same year, another traveller, Cheetam,-'34 took the road
from Simla to Srinagar; August 17, 1859, he crossed the pass of
Lunga-Lacha at 16,750 feet (5100 meters) :
I then had my first experience of the harmful effects which greatly
rarified air, bad weather, and fatigue produce at great elevations.
Vertigo, violent headache, and nausea, such are the character-
istic sensations, to which is agreeably added a feeling of intense
exhaustion, a profound physical and mental depression. Happily, in
Mountain Journeys 153
me this pleasing complication lasted only a few hours, in the middle
of the day, and again intermittently. I noticed that invariably I was
better when descending the hills than when ascending them; and that
there was a sort of connection between the appearances of the sun
and my lucid intervals.
The sufferings of my Cashmere servant and the merchants of
Caubul were evidently much more continual and acute than mine,
particularly because of a general disturbance of which they had been
complaining since the day before, at the pass of Bara Lacha.
It was impossible to destroy their absolute belief that all these
symptoms were due to the poisonous exhalations from a mysterious
plant, the "dewaighas" or "medical herb", which they are sure grows
in these regions, although they have never been able to find any ....
The man from Cashmere was sick two days. P. 137.)
A few days after, crossing of a still higher pass, that of Tung-
lung, which has an altitude of 17,750 feet (5410 meters). The
night camp was made at Larsa, at 16,400 feet:
The aacent of the 1350 feet which we had to climb was very
rugged; the slightest effort in this rarified air made our breathing very
painful. (P. 141.)
The account of Semenof 233 is interesting in that it relates to
the first journeys made in the high regions of the Celestial Moun-
tains. June 25, 1857, after camping at an altitude of 7500 feet, he
crossed the pass of Zauku. There thousands of carcasses of camels,
horses, oxen, and dogs are to be seen:
The horse of M. Kosharof broke down .... mine slipped, cut
itself deeply, and died at once; two of the horses of the Cossacks
were so exhausted that they could not go on ... . The guide assured
us that it was so difficult to breathe at the summit of the Zauku Pass
that it would be impossible to live there more than an hour and a
half. (P. 364.)
We see, in this statement of the guide, an example of the
exaggerations usual in all countries where very lofty places are
the exception. Unfortunately, Semenof does not give the altitude
of the pass of Zauku.
But no one could treat this question with more authority than
the Schlagintweit brothers, whose expeditions in the lofty regions
of Asia are among the most important journeys of this century,
and the most fruitful from the point of view of geography, history,
and the natural sciences.
They have devoted a section, in the official account of their
journey,230 to the history of the symptoms of decompression. In
it we see that they mounted to the greatest height ever attained by
154 Historical
man in mountain ascents, that is, to 6882 meters, on the sides of
Ibi-Gamin, August 19, 1855.
Here is the summary of their highest ascents:
On some very lofty plateaux which serve as pastures, a tempo-
rary dwelling for a few months was established at an altitude of
about 16,500 feet (5030 meters); it is at this height, probably the
highest of the sort in the world, that the shepherds of Thibet pitch
their tents and even build permanent dwellings.
From personal experience we can say that for ten or twelve days,
man can remain considerably above this altitude, perhaps not without
distress, but positively without any very serious consequences. In our
explorations of the glacier of Ibi-Gamin, from the 13th to the 23rd of
August, 1855, we camped for ten full days, in the company of eight
men who were our attendants, at really extraordinary elevations.
During this time, our camp was pitched at 16,642 feet (5070 meters)
at the lowest. The highest point was 19,326 feet (5890 meters); that
is the highest elevation at which we passed the night. Another time,
we camped at 19,094 feet, later at 18,300, and the rest of the time,
between 18,000 and 17,000 feet ....
One day we crossed a pass at 20,459 feet (6230 meters), and
three days before, August 19, 1855, we had climbed on the sides of
Ibi-Gamin to the height of 22,259 feet (6882 meters). So far as we
know, that is the greatest height to which anyone has ascended in
the mountains ....
On the peak of Sassar, August 3, 1856, we reached a height of
20,120 feet. Before us, the brothers Alexandre and James Gerard
ascended to 19,411 feet on the peak in Spiti, October 18, 1818 ....
So far as the symptoms to be considered in acclimatization are
concerned, we can speak from our personal experience. When we
crossed passes at an elevation of 17,500 to 18,000 feet for the first
time, we first felt serious symptoms. A few days after, when we had
traversed the highest points and passed several nights at these alti-
tudes, we were almost completely free from these disagreeable
symptoms, even at the elevation of 19,000 feet. What the consequence
of a longer stay in these lofty regions would have been, we cannot
say. But we consider it very likely that a longer residence would have
had serious effects on the health ....
The effect of the altitude varies with the individual. A healthy
man is likely to suffer less. The difference in race is not particularly
important. Our Hindu servants, who accompanied us to the highest
points, suffered from the cold more than the* Thibetans, their comrades,
but they did not feel the effects of the decrease in atmospheric
pressure more.
For most people, the influence of the altitude begins to appear
at 16,500 feet, the elevation of the highest pastures. Our camels and
our horses were very definitely suffering at about 17,500 feet.
The symptoms produced by the rarefaction are: headache; diffi-
culty in breathing; oppression in the chest, which may go so far as to
bring on the spitting of blood, and very rarely slight nasal hemorr-
Mountain Journeys 155
hages; we never saw blood issue from the lips and the ears; loss of
appetite and often nausea; muscular weakness, with a general pros-
tration and dejection. All these symptoms disappear almost simul-
taneously, in a healthy man, upon return to lower elevations. The
effects mentioned are not perceptibly increased by cold, but wind has
a very harmful effect on the symptoms experienced. As this was a
new phenomenon to us, and as it had not been mentioned by our
predecessors, we observed it carefully, and noted circumstances in
which fatigue was not a factor. On the plateaux of Karakorum, it
frequently happened even to those who were asleep under the tent
in rather sheltered places to be awakened during the night by a feeling
of oppression which must be attributed to a breeze, even a gentle one.
which had arisen during the hours of repose. When we were busy
with observations, we took little or no physical exercise, sometimes for
thirty-six hours, and our servants even less than we did. And it
often happened, in elevations which did not exceed 17,000 feet, that
the afternoon or evening wind made us so ill that we lost all taste for
food; we did not even think of preparing dinner. In the morning,
when the wind was not blowing, appetite generally returned, we were
not as ill in the morning as in the evening; this was evidently partly
because the strong winds rose usually in the second part of the day.
The effects of diminished pressure are considerably aggravated
by fatigue. It is surprising how exhausted one becomes; even the act
of speaking is a labor, one heeds neither comfort nor danger. Often
our servants, even those who had served us as guides, let themselves
fall on the snow, declaring that they would rather die at once than
take another step. From simple motives of humanity, we were often
obliged to intervene in their behalf and tear them by force from the
stupor into which they had fallen, whereas we ourselves were hardly
in a better condition of energy. (Vol. II, p. 481-485.)
The observations of more recent travellers agree completely
with what we have just reported. We must even note that, since
the existence of discomforts on lofty passes is today well known
to everyone, travellers often do not speak of them, or merely
allude to them in a few words.
So Captain Godwin-Austen,L:;7 who explored the glaciers of
Karakorum, in 1860 made the ascent of Bianchu (16,000 feet) and
Gommathaumigo (17,500 feet) without speaking of any symptom.
In his journey of 1861, he first climbed Boorje-La (15,878 feet) ;
his pulse rate was 138, and that of one of his men 104, and he
mentions no other symptom (P. 23.) But while he was ascending
a peak of 18,342 feet (5590 meters) on August 10 (this is the highest
ascent he made) he reports that "many men became ill, had violent
headaches, and lay down on the ground." (P. 34.)
And in addition, in the account -:!S of the long and important
journeys made by two young Brahmins, two brothers, whom the
English government sent to visit regions in which Europeans can
156 Historical
hardly set foot without risking their lives, there is no mention of
the symptoms of decompression. And yet the two "Pundits" cer-
tainly visited many lofty places, since they crossed the Himalayas
in Nepal, at the foot of Dhawalaghiri, followed the course of the
Brahmapoutra from Lhasa to Lake Manasarowar, and pushed on
as far as Gartokh. But since they were exclusively interested in
geography and politics, they did not heed phenomena which are
universally known, or at least they did not think they should give
space to them in their narrative.
Since this native expedition gave excellent results, a few years
afterwards, the Trigonometrical Survey sent an employe, the Mirza,
whose journey M. Montgomerie 239 has related, across Hindu-Kush
and Pamir to Turkestan. In this account there are a few details
which refer to our subject.
In January, 1869, the Mirza reached Lunghar, in the steppes
of Pamir:
The whole company, when they reached Lunghar (12,200 feet),
suffered greatly from the Dum, as the Mirza calls it, that is, shortness
of breath, etc., the usual effect of great altitudes. The natives gener-
ally consider it to be produced by a bad wind; some of the men
became almost insensible, but soon recovered when the Mirza had
them eat some dry fruits and sugar. (P. 158.)
At the pass of Chichik-Dawan (15,000 feet) they suffered
greatly; all felt extreme difficulty in breathing, which the Mirza
tried in vain to overcome with his sugar candy and dried fruits.
(P. 165.)
At the same time, an English traveller, Hayward,'40 was also
making his way towards Kashgar, but through Little Thibet, across
the enormous chain of Karakorum. He too is extremely chary of
observations relating to the rarefaction of the air.
The journey lasted from October, 1868, to June, 1869. Crossing
of the pass of Masimik, at an altitude of 18,500 feet (5640 meters) :
It presents no difficulties, is very easy, but loaded horses are
slightly affected there by the rarefaction of the air. (P. 36.)
Crossing of the pass of Chang-Lang at 18,839 feet (5740 meters)
(p. 38) ; ascent of a peak of 19,500 feet (p. 43) , of another of 19,000
feet (p. 55-58), without any physiological observation; he merely
says:
The chief difficulty at the Chang Lang pass is the distress of
loaded animals, as a result of the elevation and the rarefaction of
the air. (P. 126.)
Mountain Journeys 157
The following year, in 1870, the "Munschi" Faiz Buksh, leaving
Peshawar in the Upper Punjab, set out for Kashgar, trying, like
so many other more or less clearly official envoys, to open these
new ways by which the commerce, the diplomatic influence, and
perhaps the arms of England strive to penetrate western Turkestan.
His account -41 is very rich in details which interest us. He
lays particular stress on Pamir:
Pamir has been given the name of Bam-i-Dunya (roof of the
world) because of its height. Its great elevation is proved by the
absence of trees and the scarcity of birds; grass grows there only in
the summer. The air there is greatly rarified, so that breathing is
difficult for men and beasts. This difficulty is called tunk by the people
of Badakhshan and Wakhan, and ais by the Mogols. The liver and
the stomach are irritated. Travellers suffer from headache, and blood
flows from their noses. In people of weak constitution, the face, hands,
and feet swell. The colder it is, the more marked these symptoms are.
The natives use acid, dried apricots, and plums as remedies. At night,
if one does not have his head two feet higher than his legs, respira-
tion is hampered during sleep. These symptoms appear whether one
is afoot or on horseback.
I am thirty-four years old. On one of the peaks of Pamir, my pulse
rate was 89 per minute; I had a headache, with irritation of the liver
and stomach; once I had the nosebleed. One of my servants, named
Kadir, a native of Peshawur, aged twenty-seven, had an attack of
fever, with difficulty in breathing, irritation of the liver, and swelling
of the face and extremities; his pulse rate was 99. Another, named
Mehra, a native of Ghizni, aged twenty, felt only slight difficulty in
breathing; his pulse rate was 75. Over-feeding increases the difficulty
of breathing. (P. 470) ....
Between Ak Tash and Sarkol is a lofty peak named Shindi Kotal,
the summit of which is always covered with snow; we felt more
difficulty in breathing there than on Pamir .... Three days' journey
after Sarkol is a lofty peak called Yam Bolak, the summit of which is
always covered with snow; we experienced great difficulty in breath-
ing there also. (P. 472.)
The expedition led by Forsyth the same year from Lahore to
Yarkand, through Ladak, had to cross successively the Himalayas
and Karakorum. The account which Henderson '-'42 gives of it
frequently indicates the observation of symptoms due to the rare-
faction of the air.
June 27, 1870, crossing of the Namyika Pass, in Ladak:
Although the summit of this pass has an elevation of only 12,000
feet, several of our men had great difficulty in breathing, which con-
tinued for several hours after we had reached our camp at Karbu, 600
feet lower; some of our men could not even sleep during the night for
this reason. (P. 46.)
3ulse
Respiration
80
26
100
22
94
92
93
78
158 Historical
July 10, crossing of the pass of Chang-La, from the basin of
the Indus to that of Shyok, one of its tributaries, at 18,000 feet
(5485 meters); little snow:
It was the first time that almost everyone in camp suffered from
the rarity of the air. The following observations, made after a half-
hour's rest at the summit, may seem interesting:
Mercury barometer 15.73. Thermometer 61 °F. Water boiling at
181° F.
I walked to the summit
M. Forsyth, who was on horseback
M. Shaw, who was on horseback
Mullik Kutub Deen, of Punjab, on horseback
A Hindu of Punjab, on foot
A Thibetan, on foot
Several travellers told me that they and their companions
had suffered more while crossing this pass than on others which were
higher. We camped for the night near a little lake of sweet water, at
300 feet below the summit of the pass. The painful symptoms caused
by the rarity of the air did not disappear until the next day, when
we were at a much lower altitude. As for me, even at 19,600 feet, I
have never felt great discomfort; mine amounted only to a certain
shortness of breath after any exercise, and awakening during the night
with a feeling of suffocation which disappeared usually after a few
deep inspirations. But in several of our men the symptoms were very
serious, and even alarming sometimes. They consisted of intense
headaches, with great prostration of body and mind, constant nausea,
and such an irritation of the stomach that even a spoonful of water
was not tolerated. A great irritability of disposition was another
marked symptom; in some cases the lips became blue; in M. Shaw,
a clinical thermometer showed a temperature which had fallen 1 or 2
degrees in comparison with that of the preceding days. Having with
me a certain quantity of chlorate of potash, I gave a strong solution
of it to the patients, rather to please them than in the hope of relieving
them. However, it seemed to have a good effect, but why? I should
not dare to make a guess. I do not doubt that these symptoms of the
lofty mountains are merely temporary and that custom would end
them, as it does seasickness. They become much more intense when
one makes an ascent when he is already at a great height.
July 11, we camped 500 feet below the pass. There the headaches
and nausea stopped quickly. (P. 56 et seq.)
July 20, crossing of the pass of Cayley, a newly discovered
pass, easy of access, which is about 5900 meters high; through it
one goes from the basin of the Indus to the plateaux of Yarkand;
there was no snow. The travellers found several butterflies there.
They do not speak of any physiological disturbance.
Mountain Journeys 159
July 21, camp on high desert plains, at an altitude of 5000
meters; they suffered much from the wind:
Travellers are frequently killed by this wind, which is sometimes
so cold that it checks the vitality very quickly. Men and horses
suffered much here from the rarity of the air. Several of our men lay
down on the plain, completely exhausted, and could not reach our camp
until the next day; some horses which fell were abandoned to their
unhappy fate. (P. 77.)
They remained several days on these lofty plateaux, and in
reference to this, the narrator adds:
There are a number of observations which I greatly regret not
having made while we were at these heights, and among them
changes caused in the pulse, respiration, and body temperature. My
travelling companions offered to submit to the boredom of having
their temperature taken and their pulse counted at determined times,
but I found that I already had too many irons in the fire. The few
scattered observations which I made had no great value, but they
prove clearly that, in me at least, altitude has only a slight effect, as
the following figures show. I should say that numerous observations
made on my companions gave similar results:
Temperature
Pulse Respir. under tongue
Ordinarily 80 24 98.2
At Sakte, seated for several hours,
12,900 feet, July 9 90 25 98.3
Summit of Chang-La; 18,000 feet
(5485 meters), July 10, after walk-
ing to the summit 80 26
Lak Zung, more than 17,500 feet;
July 24 (P. 79.) 75 24 97.8
The second part of the book is devoted to natural history. The
ornithology is edited by A. O. Hume. I am quoting from it inter-
esting observations on the habitat of birds at great altitudes:
One of the points which seemed most striking to me in the
observations of Dr. Henderson is the ease with which birds seem to
live at great altitudes. Our friend the Cuckoo swings on the pendent
branches of the birches, uttering his joyous song at an elevation of
11,000 feet, while snow covers the ground. The Lapwing seems at
home at 18,000 feet (5485 meters), the "Kashmir Dipper", which lives
above 13,000 feet, seeks for insects in half -frozen torrents; the
"Guldenstadt's Redstart" hops carefree in the snow at 17,800 feet; the
Montifringilla haematopygia seems to live permanently between
14,000 and 17,000 feet, and the "Adams' Finch" is common at 13,000
feet. The long-beaked tufted Lark is in places from 12,000 to 15,000
feet, while the Mongolian "Dottrel" and the "Ruddy Shieldrake" live
at 16,000 feet, and the brown-headed "Gull" at 15,000. (P. 163.)
160 Historical
I shall end this long series of quotations with an extract from
the work which Fr. Drew L'43 recently devoted to the geography of
Jumnoo and Cashmere.
In the description of the lofty valleys of Ladak, Drew begins
with that of Rupshu, the average elevation of which is from 14,000
to 15,000 feet (4270 to 4570 meters) ; the line of perpetual snow
there is at about 20,000 feet. A wretched tribe, of one hundred
tents, lives there, the Rupshu Champas. In a special section the
author discussed the influence of the rarified air:
At great elevations, in addition to the oppression and the short-
ness of breath, one feels headaches and nausea, as happens at the
beginning of fever or seasickness, but with no modification in the
temperature of the body. In some persons, at high levels, vomiting
occurs, but has no serious consequences, and the patient recovers
when he descends to lower regions, provided however, that the organs
are not diseased; rarity of the air generally reveals lesions of the
lungs or heart.
The elevation at which these symptoms are observed varies in a
peculiar way, and it is not easy to find the cause of these inequalities.
The condition of the health has a great deal to do with it; a man in
good condition can endure a much higher elevation than a man who
is not accustomed to exercise. That is evident first when one exerts
himself a little more than usual, as in running or climbing some hill;
under these conditions, in persons who live above 6,000 feet the
symptoms usually appear at 11,000 or 12,000 feet. At 14,000 and 15,000
feet, there sometimes appears what may be called an attack of short-
ness of breath, even when one is resting. The first time I visited
Rupshu, that happened to me during the night, when I had been in
bed about a half -hour; but after a week, I overcame this tendency,
and since then I have not felt any difficulty in breathing while I was
resting, even when I camped 2,000 or 3,000 feet higher. Likewise I
knew a native of Punjab, unused to muscular labor, it is true, who
had an attack at 11,000 feet.
But although one can become accustomed to the rarity of the air
to a certain extent, and not feel it at all, the slightest effort will bring
on its effects. At 15,000 feet, climbing the gentlest slope makes one
more breathless than scrambling up a very steep hill at a lower
altitude. Talking or walking, even on a level, soon produces breath-
lessness. When one is at great elevations— and here every thousand
feet make a great change — climbing a slope is a painful labor. I have
crossed a pass at an elevation of 19,500 feet which lower would have
caused no trouble; and yet at every 50 or 60 steps, I was absolutely
forced to stop, panting, to get my breath; but yet I did not feel any
headache or other painful symptom; acclimatization to the mountains
for a month or two permitted me to sleep under these conditions.
(P. 291.)
Mountain Journeys 161
9. Africa.
Atlas. — Several summits of the Atlas in Morocco, which were
11,000 to 12,000 feet high, were visited by Dr. Hookes,244 in 1871;
he does not mention any symptoms.
Kamerun Mountains. — The first ascent was made December 22,
1861, by Burton. In the account 24r> of it which he published
immediately he mentions some strange discomforts which should
very probably be explained by the influence of the altitude:
While I was ascending the volcano, I was so tired that I could not
keep my eyes open; I felt a distress which seemed to me to be due
to fever. I was obliged to rest, I slept an hour, and at four o'clock
I was able to make this ascent. (P. 79.)
The general account 24G which he published later of his journeys
to the Kamerun Mountains and Fernando Po is no more definite:
M. Saker then complained of complete deafness. The burning
heat removed all sensation. Perhaps it was aided by the rarefaction
of the air. However we were not surprised at suffering so little in
the course of our ascent from the discomforts of which so many
travellers to Mont Blanc and in the Rocky Mountains complain. (Vol.
II, p. 121.)
We must note that they were then only at 7000 feet; but the
next day they finished the ascent of the great Peak:
As we approached the summit, the difficulties of the ascent in-
creased. Kharah dropped on the ground, almost fainting under the
rays of a burning sun, and was forced to remain there. At half-past
one, I reached the summit of the peak. (P. 155.)
January 13, 1862, another ascent by MM. Calvo, Saker, and
Mann (P. 162-181). No symptom noted.
But in the account of it published by Mann,'47 he declares that
"he was sick on the Albert Peak and compelled to descend" (P. 23) .
Finally, January 29, 1862, ascent of Burton. He camped at
10,187 feet, and reached the cinder cone of Mount Albert:
I noted again the complete absence of any suffering due to the
thinness of the air. The altitude is considerable, but not sufficient,
it appears, to cause the hemorrhages from the ears and lips expe-
rienced by von Humboldt in the Andes, or the sufferings of M. Gay-
Lussac in his balloon. (Abeokuta, Vol. II, p. 198.)
Kilimandjaro. — May 11, 1844, Rebmann -48 saw Kilimandjaro
covered with snow. The mountain is "inaccessible, the natives
say, because of the evil spirits which had killed a great many of
those who had attempted to ascend it." (P. 276.)
1 62 Historical
So he could not attempt an ascent.
In 1861, Baron de Decken reached an elevation on the sides of
the immense mountain which Thornton,"41' his companion, esti-
mated as 22,814 feet (6952 meters).
November 27, 1862, he was able to ascend high enough to feel
some discomfort. Dr. Kersten,250 who accompanied him, reports
that they stopped at 4223 meters, because of the cold, before
reaching the snow line:
The ascent (he says) continued to be fairly difficult, and we were
often forced to stop short. Anamouri, one of the men whom we had
hired, was also indisposed. (P. 36.)
Baron de Decken 250 expresses himself more definitely on the
effect of the altitude:
When I had reached a height of 4225 meters about quarter past
eleven, I stopped, as I was forced to do, since my servants could go
no further without danger of pains in the chest. Dr. Kersten also felt
the effects of the rarified air. (P. 49.)
And last, October 30, 1871, New-'1 ascended Kilimandjaro to
the snow line:
My men abandoned me, complaining of the cold. I continued with
Tofiki alone. All went well for an hour and a half; but then Tofiki
collapsed, hardly able to speak. He urged me to go on, telling me that
he would wait for me, but that he would die if I did not return. 1
went as far as the ice, broke off some pieces of it, and descended at
once.
Yes, snow in Africa, he cried with enthusiasm! What ideas
this undeniable evidence must have given the learned editor of
the Nouvelles annates des Voyages who, in 1849, denied that Reb-
mann could have seen snow on Kilimandjaro.
10. Volcanoes of the Pacific.
Borneo.— The highest peak of this vast island appears to be
Kini-Ballu, the height of which (4175 meters) is almost that of
Jungfrau.
The first attempt to ascend was made March 11, 1851, by Low.--"
He did not get above 2850 meters, and considered that the summit,
which he estimates at 13,000 or 14,000 feet, is "inaccessible for any
one without wings."
And yet, in April, 1858, he reached the summit, accompanied
by M. Spencer Saint- John. The latter felt the effects of the rari-
fied air very slightly, as his account shows:
Mountain Journeys 163
During the ascent (says Spencer)2" I suffered slightly from short-
ness of breath and felt some sluggishness in moving. But hardly had
I reached the summit when the symptoms left me, and it seemed to
me that I was lighter, that I could float in the air.
The thermometer at the summit registered 62°F. (Vol. I, p. 271.)
In June, 1858, second ascent of the same traveller. This time,
he did not say a word about physiological symptoms.
In another part of the island, another English explorer,
Brooke,-54 ascended Tabalau Indu in March, 1858. It is difficult
not to attribute to the altitude a part of the causes of this ikak
of which the natives speak and which one of his companions
experienced:
The climb was hard; the heat was excessive; every step seemed
the last one could make .... We reached the summit and rested there
with satisfaction. Poor X . . . was in great distress and lay down on
his back, while some of his servants went to seek "the friend of the
traveller", a very abundant root, from which they squeeze a cool
liquid with a slight taste of wood. It is a great mistake to drink, for
one has constant thirst, and is attacked by what the natives call
"ikak", a painful oppression in the chest, with difficulty in breathing.
(P. 305.)
Malacca. — In his ascent of Mount Ophir, Braddel 255 experi-
enced some discomfort:
When I was near the summit, I had a violent headache and severe
throbbing in my temples; I bathed my brow with brandy, which
relieved me .... But I felt a peculiar fatigue and stretched out on
the ground. (P. 87.)
Japan. — The first ascent of Fuji-yama of which I have found
an account was made in 1860 by Rutherford Alcock.L' '■ He esti-
mates at 14,177 feet (4320 meters) the height of this volcano
which has been extinct since 1707. It took him eight hours to
reach the summit; and he definitely felt the effect of rarefaction
of the air:
The second half of the ascent was much more difficult .... The
air became very rare and evidently affected respiration .... It took
more than one hour of struggling, stopping frequently to breathe and
to rest our legs and our backs, which pained us; when we reached
the top, we were absolutely at the end of our strength. The temper-
ature was 54° F. (P. 344.)
Gubbins,257 who ascended the volcano August 10, 1872, com-
plains only of fatigue. But Jeffreys,-"* whose ascent was on May 4,
1874, mentions clearly real symptoms of decompression, attacking
even the natives:
164 Historical
As we were painfully climbing, a strong desire to sleep seized us,
and the coolies could not resist it when we stopped. One of them was
even unable to go on and we had to leave him on the way. We ended
the ascent with great difficulty, and reached the summit at noon
exactly. (P. 172.)
Kamschatka.— The only known ascent of the highest volcano
of Kamschatka, Klioutchef (4805 meters), was made by Ermanr":'
September 10, 1829. He does not mention any physiological
disturbance.
Hawaii.— June 15, 1825, for the first time Europeans ascended
Mauna Kea, the "White Mountain" (4195 meters); they were a
missionary and some officers of the English vessel Blonde. The
commander Byron"00 says in narrating this expedition:
The lieutenant and the purser were so overcome by sleep that
they lay down on the bare rocks to rest.
Lord Byron in his turn ascended June 27; but he speaks of no
discomfort.
January 12, 1834, ascent of Mauna Kea by David Douglas,-61
and January 29, of Mauna Loa, "the Great Mountain" (4250
meters) : no mention of physiological disturbances. Same silence
on the part of Loevenstern,-0- who ascended Mauna Loa in Janu-
ary, 1839. Anyway, his account contains only a few lines.
The great expedition which the government of the United
States sent around the world under the command of Wilkes
made a long stay in Hawaii. From December 21, 1840, to January
13, 1841, Wilkes and several of his officers camped on the side of
Mauna Loa; several times they reached its highest point. It was
not with impunity that they lived thus for three weeks at such
heights; while they were ascending, they suffered severely:
The thermometer had dropped to 18°, and many of our men were
severely affected by mountain sickness, with headache and fever, so
that they were unable to do anything. I myself suffered greatly from
it, with violent throbbing in my temples, and short, painful, and
distressing breathing. (P. 149.)
Officers, sailors, and natives reached with countless difficulties
the foot of the terminal crater, at 13,440 feet (4095 meters) . The
next morning, their distress was somewhat abated. The camp
was kept at this great height for three weeks, and the detailed
account of the geodetic and physical operations in which they
were engaged shows that they suffered frequently from mountain
sickness:
Mountain Journeys 165
Everyone experienced it more or less. Dr. Judd remarked that
in the natives the symptoms were ordinarily colics, vomiting, and
diarrhea; one or two were affected by the spitting of blood, some had
fever and chills. Almost all of us had yellowish skin, headache,
and vertigo, some had asthma and rheumatism ....
Dr. Judd also found that patients were very hungry without
being able to eat. During the day, the least exercise increased the
pulse rate of all of us by 30 to 40. (P. 177.)
Since that time, I have found in the accounts of the travellers 264
who have ascended the volcanoes of Hawaii or Maui no mention
of physiological distress.
I See Jourdanet, Influence de la pression do I'air sur la vie de I'hommc. Paris, 1875. Vol.
If P- 212. . ,
-Relation vcridique de la conqnetc du Perou: in Collection de voyages pour servir a
Vhistoire de la decouvertc dc t'Amaiquc, by Ternaux-Compans, Vol. IV, Paris, 1837. _
3 Histoire d,es querres civiles des Es'pagnols dans les Indcs. Translation of Baudoin, p.
200. Paris, 1650. (The original work was published in Cordova in 1613.) Book II, Chap. XX.
Vol. I. •
4 Histoire veritable d'un Voyage curicnx dans VAmeriquc, from 1534 to 1554. In the
Ternaux-Compans collection, Vol V.
5 Acosta (Jose de) Historia Natural y Moral de las Indias: en que se trata de cosas
notables del Ciclo, d.e los elementos, mctalcs, plantas, v animales, etc. (Seville, 1590)
''■Historia general de los Hcchos do los Castcllanos en las islas y ticrra firme del mar
Oceano. Madrid, 1615. Decada V. Book X. Chap. V, Vol. Ill, p. 20, I.
7 New edition, Vol, VI, VII, VIII, IX. Paris, 1781.
8 Relation du voyage de la mer dit Sud aux coles du Chily ct du Perou, made during
the years 1712. 1713, and' 1714. Paris, 1716.
0 Relation abregce du voyage fait au Perou, par M. M. de I Academic royale des sciences,
pour mesurer les degres du meridicn aux environs de I'cquateur, et en conclure le figure dc
la terre. Memoires de VAcademie des sciences de Paris, 1744, p. 249-297.
10 Journal du voyage fait par Vordre du Roi, a I'cquateur. 2 vol., Paris, 1751.
II Memoires philosophiques. historiqucs, physiques, concemani la decouverte de VAmeriquc.
French translation, Vol. I, 1787.
12 Voyage aux regions equinoxialcs du nouvcau continent, fait en 1700-1804. Paris, 1814.
13 Leitre de M. Humboldt adrcssce an citoven Delambre. datee de Lima, November 25.
Ann. du Museum d'histoire naturellc. Vol. II. p. 170-180, year XI (1803).
14 Extrait de plusicurs lettres dc M. dc Humboldt. Ann. du Museum, Vol. II, p. 322-337, year
XI (1S03).
15 Von Humboldt (Alexander), Notice sur deux tentatives d'ascension au Chimborazo.
Annals of Chemistry; second series: Vol. LXIX, p. 401-434; 1838. Translated by Eyries from
the Jahrbuch de Schumacher for 1837.
1(1 I could not find this statement in Zumstein's accounts.
17 Tableaux de la nature, translated by Eyries. Paris, 1828, Vol. II.
18 Histoire contemporainc de I'Espagne. 2 vol. Paris, 1869.
19 Gervinus. Histoire du dix-ncuvicme siecle, Mirssen translation, Vol. VII. Paris, 1865.
2" Historia dclla Rcvolucion hispano-amcricana. Madrid, 1830.
21 Carta descricion dc los viages hcchos en America par la Comision cientifica mandada
par el Gobicmo Espanol. durante los anos 1862, 1866. Madrid, 1866.
22 Sketches of Bucnos-Axres. Chile, and Peru. London, 1831.
23 Travels in Chile and la Plata. 2 vol. London, 1826.
24 Travels in South America, during the years 1819-20-21. 2 vol. London, 1825.
* Travels into Chile over the Andes, in the years 1820 and 1821. London, 1824.
20 Narrative of a journey across the Cordillera of the Andes, in the years 1823 and 1824.
London, 1824.
27 Rough notes taken during some rapid journeys across the Pampas and among the
Andes. London, 1828.
28 Journal of a passage from the Pacific to the Atlantic. London, 1829.
^Journal of a voyage to Peru. London. 182S.
30 Itineraire de Valparaiso a Buenos-Ayres. published in the second volume of the Journal
de navigation autour du globe, of Bougainville. Paris, 1837.
31 Travels in various parts of Peru including a year's residence in Potosi. 2 vol. London,
iaso.
32 Observations on the geography of southern Peru, including survey of the Province of
Tarapaca, and route of Chile by the coast of the Desert of Atacama. Journal of the Royal
Geographical Society. London, vol. XXT. p. 00-130; 1851.
33 D'Orbigny, Voyaqc dans VAmeriquc meridionale, made during the years 1826-1833, 7 vol.
Paris, 1835-1847.
34 Reise in Chile, Peru, und auf dem Amdsonenstrome, wahrend der Jahre 1827-1833, 2 vol.
Leipzig, 1836.
35 Ascension au Cliimboraco, made December 16, 1831. Ann. de Mm., second series, vol.
LVTTT. p. 150-180; 1835.
"i; Reise urn die Erde. in den Jahren 1830-32. Berlin 1835. vol. II.
"Narrative of the voyages of Adventure and Bcaqle; 1826-1836, third volume; Journal and
remarks. London, 1832-1836.
166 Historical
38 Narrative of a journey from Lima to Para. London, 1836.
38 Practical observation on the diseases of Peru, deseribed as thev occur on the Coast and
in the Sierra. Edinburgh Med. and Surg. Journal, vol. LIV, LVI, LVII, LVIII, 1839. 1841.
1842, 1843.
*" Fragment d'un voyage dans Ic Chile el an Cusco. Bull, dc la Soc. de geogr. Second
series, vol. XIX, p. 15-57; 1843.
41 Peru, Rciseskizzen aus den Jahrcn J838-1842. 2 vol. Saint-Gallen, 1?46.
42 Expedition dans les parties centrales de I Amerique du Slid. Hist, du voyage, vol. Ill
and vol. IV. Paris, 1851.
43 Voyage a travers V Amerique du Sud, de V Ocean Pacifique a focean Atlantique. Paris.
44 The U. S. naval astronomical Expedition to the southern Hemisphere during the years
1819 - 185(?) 2 Chile, Philadelphia, 1859.
46 Report of a journey across the Andes, between Cochabamba and Chirnore. J. of the
royal geographical Society, vol. XXIV, p. 259-265; 1854.
*a Voyage dans le nord de la Bolivie et les parties voisines du Perou. Paris, 1853.
47 Voyage dans I' Amerique du Sud, Perou et Bolivie. Paris, 1861.
48 Rclse durch die La Plata-Staatcn. ausgefuhrt in den Jahren 1857-1860.
49 Travels in Peru and India. London, 1862.
50 Description geographique et statisiiquc dc la confederation argentine. 3 vol. Paris.
1860-64.
51 Mouqueron's translation. Paris, 1863.
52 Dc la phthisic pulmonaire dans ses rapports avee I' altitude et avee les races au Perou
el en Bolivie. Du soroche on mal des inoutagncs. Thesis of Paris, 18(32.
53 The reference is to Castelnau.
r'4 Relatione dclla gita da curico net Chili a sun Raphael nclla Pampa del sur ( febraio
1866). Parma. 1869.
55 Rcise iiber die Cordilleren von Arica bis SaniOrCrus. Extrait in Petermann's Mitthcil-
nngen, Vol. XI; 1865.
56 Exploration du cratere du Rucii-Pichincha. Nouv. ami. des voyages, Vol. CVII, p.
106-112; 1845.
r'7 Ascension du Pichincha. Chalons- sur-Marne, 1858.
58 Remy (Jules) et Brenchley, Ascension du Chimborazo. Nouv. ann. des voyages, Vol.
CLIII, p. 230-238; 1857.
50 Voyages au Chimborazo. a i Altar, et ascension au Tunguragua, letter of April 18. 1873.
Bull, de la Soc. de geogr., sixth series, vol. VII. p. 258-295; 1875.
'*> Journey of M. Wafer, in which is found the description of the isthmus of America;
inserted in volume IV of the Voyage aux tcrres Australes, of G. Dampier. Rouen, 1715.
61 Voyage geographique aux republiques de Guatemala et de San Salvador. Paris, 1868.
MAufenthalt and Reisen in Mexico in den Jahren 1825 bis 1834. Stuttgart, 1856.
63 Recherches de Pathologic comparee. Cassel, 1853.
04 Jourdanet, Prcssion dc Vair, vol. I, p. 212.
*'"• L. \Y. Glennie, The ascent of Popocatapetl (sic). Proceedings of the geolog. Soc. of
London, vol. I, n. 7.3; 1834.
m Gros (baron), Ascension au sommet du Popocatepetl. Letter of May 15, 1834. Nouv.
ann. des voyages, vol. LXIV, p. 44-68, 1S34.
67 Ascension du volcan du Popocatepetl (mountain of smoke) in September, 1856. Nouv.
ann. des voyages, vol. CLIII, p. 304-317; 1857.
08 Recit d'une ascension du Popocatepetl, by MM. A. Dollfus, de Montserrat and Pavie,
Archives de la Commission scicntifique du Mexique, vol. II, p. 187-201. Paris, 1866.
69 Reisen in den Vcreinigtcn Staaten, Canada und Mexico. Leipzig, 1S64.
70 Attempted ascent of Orizaba. Alpine journal, vol. Ill, p. 210-214. London, 1867.
71 Report of the exploration to the Rocky Mountains in the year 1842. Washington. 1845.
10 Reports of explorations and surveys to ascertain the most practicable and economical
route for a railroad from the Mississippi River to the Pacific Ocean. Vol. II. Washington, 1855.
73 Ascent of Mount Hood. Extract in Proceed, of the Roy. Geogr. Soc. vol. Ill, p. 81-84;
1867.
74 Petermann's Mitthcil., vol. XIV, p. 151; 1868.
75 Mountaineering on the Pacific. Alpine journal, vol. V, p. 357-367. London, 1872.
76 Ibid., vol VI, 192-193; 1874.
77 Opere, vol. 4. Venet, 1729.
78 Aetnac topographia; in Thesaurus antiq. sicul. Lugd. Bat., 1728.
70 De Rebus siculis. Catane, 1749.
80 De motu animalium. Pars altera. Rome, 1681. .
81 Voyage dans la Sicile et dans la grande Grece, addressed by the author to his friend,
M. Winckelmann; translated from the German (without author's name). Lausanne, 1773.
82 Voyage en Sicile et a Malthe, vol. I, p. 225. Amsterdam, 1775.
83 Voyage pittorcsque des isles de Sicile, de Malthe, et dc Lipari, vol. II, p. 103. Pans.
1784.
84 Voyage en Sicile. Paris, 1788. . .
85 Relation d un voyage fait depuis pen sur ce volcan: in J/oyagc pittorcsque ou description
du royaumc de Naples et de Sicile, by the abbe Saint-Non. Fourth volume, p. 91-104. Paris, 1785.
80 Built by Empedocles, according to the legend. (See Fazello, loc. cit., vol. I, p. .)
87 Voyages dans les deux Sidles, translated by G. Toscan, Vol. I, Paris, year VIII.
88 Descrisione dell' Etna. Palermo, 1818.
^Voyage critique a I' Etna, en 1819, vol. I. Paris, 1S20.
90 Souvenirs de la Sicile. Paris, 1823.
91 Note sur les effets physiologiques de la rarefaction de Vair a de grandes hauteurs, boc.
philomatique, p. 120-122; 1822. . .
92 "In the midst of it is seen a very steep, round mountain which they call Pico de Teithe.
the topography of which is as follows: its peak is very steep and includes 15 leagues, which
amount to more than 45 English miles." Description des Canaries, by the Englishman Nicols
or Midnal; in Traite de la navigation, by Pierre Bergeron, preface to Voyages faits en Asie
dans les douzicmc, trcizicmc, quatorzicmc at qninziemc siccles, vol. I, p. 119. La Haye, 1735..
Mountain Journeys 167
M A Relation if the Pico Teneriffe received from some considerable merchants and men
worthy of credit, who went 'to the top of it. History of the Royal Society of London, by Th.
Sprat, third edition. London, 1722, p. 200-213.
94 Philos. Transac, Sept. 12, 1670. Vol. XXIX, p. 317-325, 1717.
95 An account of a journey from the port of Oratava in the Island of Teneriff, to the top
of the Pic in August 1715. Mem. of the Royal Soc. of London, second edition, vol. VI, p. 1,2-1,7.
London, 1745.
M Memoirs of the Academy of Sciences of Paris for 1746, p. 140-142
97 The History of the Discovery and Conquest of the Canary Islands. London, 1,64.
9> Relation d'un vovage a la recherche de la Perouse, made by order of the Constitutional
Assembly, during the years 1791-1792 and during the first and second years of the French
Republic. Paris, year VIII. , .,„._., VT
99 Essais sur les isles Fortunees et I'antique Atlantide. Paris, Germinal, year XI.
^""Voyage aux regions equinoxiaJes du nouveau continent, vol. I, p. 123-145. Paris, I814-
101 Lettre au citoven Devilliers fils. Journal de phvs., de chim. et d'hist. not., vol. LVII.
p. 55-63; 1S03. _ .
^Description physique des iles Canaries, Translated by Boulanger. Paris, 1836.
103 Voyage de i Astrolabe, made during the years 1826-27-28-29. Histoire du voyage, vol.
I; Paris. 1830.
104 Voyage au Pole Slid. vol. I. Paris ,1841. ,
i<>5 Voyage around the world of the Astrolabe and the Zelee, under the command of
Dumont d'Urville. Paris, 1S42. .
106 Voyage geologique aux Antilles et aux iles de Teneriffe et de Fogo. Paris, 1S4S; vol. 1,
p. 65-79.
'"'Journal d'un voyage en Chine in 1843, 1845, 1846. Paris, 1S48, 3 vol.
108 Sixteen rears of an artist's life in Morocco, Spain, and the Canary Islands, 2 vol.
London, 1859. „„_ _ , . Al
. 109 Vie de Jean d'Aranthon eve que d'Alex, de 1660 a 1695; Lyons, 1,67. Quoted in the
Guide ■ itineraire du Mont-Blanc, of V. Payot. Geneva, 1S69; p. 161.
110 Eletnenta physiologiae, vol. Ill, p. 197. Lauzanne, 1761.
111 Disquisitiones physicae de meteoris aqueis. Pars prima. Tiguri, 1786.
iriDie Bergkrankheit. Le.ipzig, 1854, p. 71.
113 Nouvelle description des glaciercs et glaciers des Alpes, second edition. Geneva, 3 vol.;
1785.
114 Tableaux topographiques, etc de la Suisse, vol. I. Paris, 1,80.
115 Voyages dans les Alpes, 4 vol. Geneva; 1786-1796.
110 The exact height is 3655 meters.
"''Narrative of a journey from the village of Chamouni, in Switzerland, to the summit of
Mount Blanc, undertaken on Aug. 8, 1787. Thomson's Annals of Philosophy, vol. IX, p. 97-103;
1817.
118 Letter from M. Bourrit to the editor uf the Bibliothequc britannique. Biblioth. but.
de Geneve, vol. XX. p. 429-433; 1802.
ii» Vovage an Mont-Blanc. Vienna, Gerald Company.
1211 BibHo-thcque universelle de Geneve, vol. IX, p. 84-89, 1818.
l* Notice sur un voyage au sommct du mont Blanc, ibid., vol. XIV, p. 219-234, 1820.
vsi Relation de deux tcntatives rccentes pour monter sur le mont Blanc. Bibliotheque
universelle de Geneve, vol. XIV. \>. 3U1-323; 1820. Hamel has since published a more
detailed account of his journey, with historical notes, under the title of Beschreibung zweier
Reisen auf den Mont-Blanc. Vienna, 1821.
123 Hamel makes a mistake here; he was still about 700 meters from the summit (Lepileur).
124 Notice sur une nouvelle ascension au mont Blanc. Biblioth. univ. de Geneve, vol. XXI.
p. 68-75, 1822.
135 Details dune ascension au sominet du mont Blanc, Ibid, vol. XXIII, p. 137155 and
237-244, 1823.
*** D. Clark and Capt. Sherwill, Qitclques details sur leur expedition au mont Blanc.
Biblioth. univ. de Geneve, vol. XXX, p. 245-246, 1S25.
,2f Ascension du mont Blanc en 1827. Nouv. ami. des voyages, vol. XL. p. 265-269, 1828.
12s Reise auf die Eisgebirge des kantons Bern und Ersteigung ihrer hochstergipfel in
sotnmer 1812. Aarau, 1813.
129 Dr. Parrot. Ueber die Schneegranse auf dcr mittaglichen scite des Rosagebitrges und
barometrische Messungen. Schweiggers journal fur chemie und physik, vol. XIX, p. 367-423, 1817.
i3o They are told verbatim in the Bibliothequc universelle, vol. XXVIII, p. 66-77, 1825.
Zumstein's notes were published in Vienna in 1S24, by Baron von Welden, in a book entitled:
Der Monte Rose, which I could not procure. I am borrowing the preceding details from an
article published by M. Briquet under the title of Ascnsions aux pics du mont Rose. (Bibl. univ..
vol. XII. p. 1-47; 1861.)
131 Naturhistorische Alpenreise. Solothurn, 1830.
lxlApercu sur la topographie medicale de V hospice du mont Saint-Bernard. Nouveau jour-
nal de Med.. Chim.. Pharm. etc. vol. VII, p. 29-37; 1820.
133 Ascent to the summit of mont Blanc, Sept. 16-18, 1834. Edinburgh new philos. journal,
vol. XVIII, p. 106-120; 1835.
134 Ascension au mont Blanc, translated from the English by Jourdan. Geneva, London,
1838.
135 Influence on the human body of ascents of high mountains, Revue medicale, 1842; vol.
IV, p. 321-344.
130 Excursions et sejours dans les glaciers et les hautes regions des Alpes, of M. Agassiz
and his travelling companions. Neufchatel, Paris, 1844.
137 Revue Suisse. Neufchatel, June, 1843.
138 Journal d'une course faite aux glaciers du mont Rose et du mont Cervin. Biblioth.
univ. de Geneve, Second series, vol. XXVII, lS4fl.
139 Ausflug nach dem Aletsch Eismeer und Ersteigung dcr Jungfrau (4167 m.). Quoted in
extenso in Materiaux pour Vetudc des glaciers, by Dollfus-Ausset. vol. IV. 1864.
140 Beobachtungen iibcr den Einfluss der verdunnte Lit ft und des stdrken Sonnenlnhtes
auf holier Gebirgen, etc. Osterreich. med. Johrb. N. Folge, vol. XXXII; 1843.
168 Historical
»« Travels through the Alps of Savoy.— Edinburgh, 1843. , . .
i4aMetn. sur les phenomenes physiologiques, observed on ascending to a certain neiRnt in
the Alps. Revue medicate, 1845, vol. II. AT . ,
143Z?<?ifjr ascensions scientifiques an mont Blanc.— Revue des Deux-Mondes, number ot
*** Ascension dn mont Blanc par la route de Saint-Germain— les Bains.— Nottv. ann. des
voy., vol. CLXIII, p. 358-36-2, 1859.
140 Tyndall, The glaciers of the Alps.— London, 1660.
146 Hours of exercise in the Alps.— Second edition.— London, 1871.
147 Der mont B/a»c. Darstellung der Besteigung desselben am 31 juh, 1,«. 2 August 1859.
rlin,
us TJ
p. 66-106, 1865. .... , , ,
149 Deux ascensions au mont Blanc en 1S69; Recherches physiologiques stir de vial des
tagnes {Lyon medical, 1869.)
150 Histoire du mont Blanc. Paris, 1873.
151 Ascensioii du mont Blanc. La Nature, Oct. 10, 1874.
152 Le mont Blanc et Chamounix. Geneva, no date.
153 Alpine journal, vol. V, p. 189.— London, 1872.
154 Ascent of the Fihsterraar-hom— Peaks, Passes and Glaciers.— London, 1So9,
155 A night bivouac on the Grivola.— Peaks, Passes, and Glaciers.— second series, vol. 11.—
London, 1862. . „ . _ . „, .
1S0 Schweitzer. The Breithorn (3735) ascension in 1861.— Peaks, Passes, and Glaciers-
Second series, vol. 1.— London, 1862. •
157 Ascent o/ tfce Deiif Blanche (June 9, 1862). 77s<? /Jtyme Journal, vol. I.— London, 1864.
158 Stephen (Leslie), 77ie Jungfrau-joch and Viescher-joch. Alp. joum., vol. L— London.
159 Reg. Somerled Macdonald, Parage of the Roththal Sattel (August, 1864). Alp. joum.,
vol. II.— London, 1866.
100 The Studer-Joch. Alp. joum., vol. L— London, 1864. , . . ,. . ,„
101 Ascension al monte Rosa nell' agosto 1864. Bulletino del Club alpino italiano. vol. VI.
P' l™ Ascension de la Jungfrau; Annuairc du Club alpin francais, first year, 1674, p. 211-219.
—Paris, 1875.
ia Peaks, Passes, and Glaciers, p. 482-509.— London, 1859.
104 Paris, fifth edition; 1874. .
105 /4:?c<?h£ of f/ie Grivola.— Peaks, Passes and Glaciers.— Second series, vol. 11.— London. l»bl.
1,e On Mountains, and on Mountaineering in general. Alpine journal, vol. V, p. 241>-24S, 1872.
167 Philosophical transactions, Sept. 12, 1670.
las Description des Pyrenees, 2 vol.— Paris, 1S13.
urn He even spat blood, according to Gondret (Mem. concernant les effets de la pression
atm. sur le corps humain; Paris, 1819. (P. 44.) _
170 Voyage au sommet du mont Perdu.— Ann. du Museum d'historie naturelle, vol. Ill, 1804.
171 Tableau des Pyrenees francaises, 2 vol.— Paris, 1828.
17- Rapport fait au Counseil des mines sur un voyage a la Maladctta, par la vallee de
Bagne'res-de-Luchon.— Journal des Mines, Messidor, year XII, vol. XVI, p. 249-282; 1804.
173 Ueber die Beschleunigung des menschlichen Pulses nach Maaszgabe der Erhohung des
Standpunkets uber der Meeresfldche.—Frorieps Notizen, vol. X; 1825.
*74 Voyage a la Maladctta.— Paris, 1845.
175 Recueil des ascensions au pic du Nethou, from 1842 (first ascension) to 1868.— Bull, de
la Societe Ramond, 1872, p. 15-24, 193-198; and 1S73, p. 49-58.
718 Ford, A Hand-Book for travellers in Spain— London, 1847.
177 Voyage au mont Caucase et en Georgie— Paris, 1823.
178 Voyage a la vallee du Terek. N. Ann. des Voyages, vol. LI, p. 273-324; 1S31.
179 Voyage dans les environs du mont Elbrous dans le Caucase, undertaken in 1829.— Report
made to the 'imperial Academy of Sciences of St. Petersburg— St. Petersburg, 1630.
1S0 Voyage dans les rallies centrales du Caucase, fait en 1836 et 1837.— N. Ann. des Voyages,
vol. CXVIII, p. 276-328, 1848. w , ^ttt n_
181 Reisen und Forschungen im Kaukasus, 1865.— Peterm. Mitth, vol. X11I, 1867
182 Journey in the Caucasus, and Ascent of Kasbek and Elbrus.— The joum. of the royal
oeogr. Society, vol. XXXIX, p. 50-76; London, 1869.— Itinerary of a Tour in the Caucasus:
Alpine Journal, vol. IV, p. 160-166; London, 1870.— The Caucasus, by C. Tucker (Ibid. 421-42f>.)
»m Itinerary of a Tour in the Caucasus made bv F. Gardiner, F. C. Grove, A. W. Moore
and A. Walker, with Peter Knubel of St. Niklaus.— Alp. Journal, vol. VII, p. 100-103; London, 18(4.
1S4 An ascent of Elbrus.— Alpine Journal, vol. VII., p. 113-124; London, 1875.
"-Voyages faits en Asie, dans les XII, III, XIV, et XV siecles— The Hague, 1735.
180 Philosophical transactions, Sept. 12, 1670.
187 Relation d'un voyage du Levant, 2 vol.— Paris, 1717.
WReise sum Ararat.— Berlin, 1834.
189 Magasin fur die Litteratur des Auslandes; 1835, no. 34.
190 Gazette russe de I' Academic ; 1838, nos. 21, 23.
191 Journal le Caucase; 1846. nos. 1, 5 7. r-vvv
™* Journal le Caucase; 1850, no. 50.— Translated in Nouv. Ann. des Voyages, vol. CAAA.
p. 334-349; 1851. _ ,
™3 Reisen im Armenischen Hochland in Sommer 1871— Second part: West— Peterman s
Mittheilungen, 1873.
194 Notice d'un voyage dans I'Asic-Mincure, faite en 1837.— iV. Ann. des Voyages, vol.
LXXXI, p. 153-196; 1839.
1913 An Account of the Ascent of Mount Demavend, near Tehran, in September, 1837.—
Joum. of the R. geograph. Soc, vol. VIII, p. 109; 1838.
1M R. F. Thompson and Lord Schomberg H. Kerr, Journey through the Mountainous Dis-
tricts North of the Elbruz, and Ascent of Demavend, in Persia.— Proceedings of the royal
geograph. Soc. vol. Ill, p. 2-18; 1859.
197 Great mistake; the height of Demavend is 5620 meters.
Mountain Journeys 169
19SiLe livre de Marco Polo, citoyen de Venise, drawn up in French at his dictation, in
1(208, by Rusticien de Pise.— Published by Pauthier. Paris, 1865.
199 Purdon On the Trigonometrical Survey and Physical Configuration of the valley of
Kashmir.-], of R. Geogr. S., vol. XXXI, p. 14-30; 1S61. .
200 Memioires stir les contrecs o<ccidentales, translated from the Sanskrit into Chinese, in
the Year 648, by Hiouen-Thsang, and from the Chinese into French by Stanilas Julien, vol I.—
1201 Klaproth, Description du Thibet, translated from the Chinese— Paris, 1831.
202 Voyages an Thibet; translated by Parraud and Billescoq.— Paris, year IV.
103 Voyages de Fr. Bemicr, vol. II, letter IX— Amsterdam, 1699.
2<"2*5 Description de la Chine of P. du Halde, vol. IV— Paris, 1735. .
206 Letter of April 16, 1710. Lettres edifiantes. New edition, vol. VII, p. 430-435— Paris, 1781.
301 An Account of the Kingdom of Thibet, by J. Stewart— Phil, transactions, vol. LVII.
p. 465-492; 1777. , _ .
'-"" Ambassade an Thibet et an Boutan, translated by Castera, 2 vols.— 1 aris, 1800.
509 A Journcv to Sirinagur .—Asiatic researches, vol. VI, p. 309-3S1; 1801. _ _
410 A Journey to Lake Manasarovara in Un-des, a Province of Little Tibet. Asiatic re-
searches, vol. XII", p. 375-534— Calcutta, 1816. . .
211 Travels in the Himalayan provinces of Hindustan and the Penjab; in Kunduz and
Bokhara; 2 vol.— London, 1851. . .
212 Journal of a Tour through Part of the snowy Range of the Himalaya mountains, and to
the sources of the Rivers Jumna and Ganges— London, 1820. This journal was published in
abridged form in the Asiatic researches, vol. XIII, p. 170-249.— Calcutta, 1820.
213 Vol. XXII, p. 415-430.-London, 1820.
214 Account of Koonawur. in the Himalaya.— London, 1841'.
215 First part: journey out. Account of part of a journey through the Himalaya moun-
tains—The Edinb. Philos. journal, vol. X, p. 295-305; 1824.— Second part, journey back. Journal
of an Excursion through the Himalaya mountains, from Shipke to the Frontiers of Chinea.
Tartary.—Thc Edinb. Journal of Science, vol. I, p. 41-51 and p. 215-244; 1824. These two
articles are reprinted in the Journal of the Asiatic Society of Bengal, vol. XI, p. 363-391;
1842. My quotation is taken from this publication.
2115 Lloyd: Narrative of a journey from Caunpoor to the Boorcndo pass, with Capt. Alex.
Gerard's account of an attempt to penetrate by Bekken to Garoo and the Lake of Manasarowara.
—London. 2 vol. 1840. .
217 Al Gerard, Account of a Survey of the valley of the Setlej River, in the Himalaya
mountains.— The Edinb. Journal of Science, vol. V, p. 270-288, 1826, and vol. VI, p. 28-50, 1827.
21S Account of Koonawur in the Himalaya. Published after his death by G. Lloyd.
London, 1841.
210 Journal of a Survey to the Heads of the Rivers Ganges and J umma. Asiatic researches,
vol. XIV, p. 60-152.— Calcutta, 1822.
230 Voyage par les monts Himalaya aux sources du Djcmna et de la au-v frontieres de
ran fire chiuois ; d'avril en Oct. 1827.— AT. Ann. des Voyages, vol. LXVII, p. 127-188, 1835.
221 Corresp on dance inedite, vol. II, 1867. — Lettre a MM. les. Professeurs Administrateurs
du Museum, a Paris,
222 Voyage dans I'Inde, pendant les annees 1828 d 1852.— Paris, vol. II, 1641.
223 The lake is at an altitude of 4650 meters.
324 Bcrghaus Annalen, vol. V.— Berlin, 1832.
225 A personal narrative of a journey to the source of the River Oxus, in the years 1836,
1S37, 183S— London, 1840.
22s Cabool; in the years 1836, 3-8.— London, 1842.
227 Souvenirs d'un voyage dans la Tartarie, le Thibet et la Chine, en 1844-1846, vol. II.
Paris, 1850.
-^ Brief c aus Indien. — Braunschweig, 1847.
2,29 Western Himalaya and Tibet; a narrative of a journey through the mountains of
Northern India, during the years 1647-48. — London, 1852.
230 Himalayan journal; or notes of a Naturalist, 2 vol. — London, 1854.
231 Ascension du Sumcni-Parbitt (Himalaya).— N. Ann. des Voyages, vol. CLII, p. SOS-
SCO; 1856.
232 The adventures of a Lady in Tartary, Thibet, China and Kashmir.— London, 3 vol., 1853.
M3 Trips in the Himalaya.— Alpine Journal, vol. IV, p. 73-93; London, 1870.
234 The Tibetan Route from Simla to Srinagar— Alpine Journal, vol. Ill, p. 118-153;
London, 1867.
235 First ascent of the Tian-Shan or Celestial mountains, and visit to the Upper Course of
the Jaxartcs or Sxr-Daria, in 1S57.— The Journal of the roy. geogr. Soc; vol. XXXI, p. 356-
36.5; lf-61.
236 Schlagintweit (Hermann, Adolph and Robert de), Results of a scientific mission to
India and High Asia, 1S54-1S58; 4 vol.— Leipzig and London, 1861-1866.
237 On the Glaciers of the Mustakh Range.— The Journal of the royal geogr. Society, vol.
XXXIV, p. 19-55; London, 1864.
238 Reisen und Aufnahmen ztveier Punditen (gcbildcter Indier) in Tibet; 1865 bis 1866. —
Petermann's Mittheilungen; vol. XIV, p. 233-243; 276-290, 1868.
239 Report of "the Mirsa's" Exploration from Caubul to Kashgar. — The Journ. of the roy.
geogr. Soc, vol. XLI, p. 132-192; 1871.
'^'Journey from Leh to Yarkand and Kashgar, and Exploration of the sources of the
Yarkand River.— The Journal of the roy. geogr. Soc, vol. XL, p. 33-166; 1870.
^l Journey from Peshazcar to Kashgar and Yarkand in Eastern Turkestan.— The Journ.
of the roy. geo'gr. Soc, vol. XLII, p. 44S-473; 1872.
242 Henderson and Hume, Lahore to Yarkand. Incidents of the route and natural history
of the countries traversed by the Expedition of 1870, under T. D. Forsyth. — London, 1876.
243 The Jumbo and Kashmir territories, a geographical account. _ London, 1875.
244 Letters to S. Roderick Murchison giving an account of his Ascent of tlve Atlas. —
Proceed, of the roy. geogr. Society, vol. XV, p. 212; 1871.
245 Relation d'une ascension aux monts Cameron (Afrique occidentale). Translated in N.
Ann. des voyages; vol. Ill, p. 71-107; 1863.
170 Historical
-* Abeokuta.— London, 2 vol., 1863. ,„■,-, i vi
247 Forscliungen an dcr Westkuste von Africa— Petermann s Mtttheilungen, vol. Al,
' *» Journal dune excursion au Djagga, le pays dcs nciges de l'Afriqu,e orientate.— N. Ann.
des Vox; vol. CXXII, p. -'.07-307. 1S4'J.
2iu Notes on a journey to Kilimandjaro, made in company of the Baron von der Uecken.
-The Journal of the R. geog. Soc; vol. XXXV, p. 15-21; 1865 _ .,»,„.,
**> Ascension du Kilimandjaro, dans I'interieur de I Ajnque oncntale. N. Ann. aes
Voyaqes; 1864, vol. I, p. 28.
251 Alpine Journal; vol. Vi, p. 51-52.— London, 1874, issue of April, 1872.
*^ Notes of an ascent of the mountain Kina—Balozc (The Journal of the Indian Archi-
pelago. Vol. VI, p. 1-17). — Singapore, 1852.
253 Life in the forests of the far East. 2 vol.— London, 18S2.
254 Ten vears in Sarawak.— London, 1866.
255 Note's of a Trip to the interior from Malacca. The Journal of the Indian Archipelago,
vol. Vi, p. 73-104.— Singapore, 1853.
«" Narrative of a joumev in the interior of Japan, in I860— The Joum. of the R. Gcograph.
Soc., vol. XXXI, p. 321-356; 1861. „ tt m n
™ Ascent of Fuji-Yama. Proceedings of the Royal Geogr. Soc, vol. XVII, 1873; p. -8- .9.
** Ascent of Fuji-Yama in the Snow. Proceedings of the Royal Geogr. Soc, March 18.o:
'"MReise urn die Erde, in die Jahren 1828; 29 und W.—Historique, third vol., p. 363 et seq.
w I'ovage of H. M. S. Blonde to the Sandwich Islands in the years 1824-1825.— London. 1826.
261 Extract from a private Letter addressed to Captain Sabine— Journal of the R. Geograph.
Soc. vol. IV, p. 333-344.— London, 1834.
282 Apercu dun viyage autour du monde. Bull, de la Soc. de. Geogr., Second Series, vol.
'*»' Narrative of' the United States Exploring Expedition during the years 1838, 39, 40, 41,
42, vol. IV.— Philadelphia, 1844. .. ■
264 Sawkins, On the I'olcanic Mountain of Hawaii. Joum. of the Roy. Geogr. Soc, vol.
XXV p 191-194; 1855. Robert Haskell, On a Visit to the Recent Eruption of Manna Loa.
Hawaii. The American journal of science and arts. Second series, vol. XXVIII; 1859, p. 66-71.
- Wilmot, Our Journal in the Pacific, London, 1873.
Chapter II
BALLOON ASCENSIONS
At the end of the 18th century, the remarkable discovery of
the Montgolfier brothers introduced a new element into the ques-
tion of decompression. In this case, the traveller no longer climbs
laboriously and slowly to the regions where rarefied aid can act
upon his organism; he is carried there without fatigue and with
great speed.
We are not interested in the montgolfiers, or hot-air balloons,
since ordinarily they can mount only to very moderate heights.
We shall simply note that the first aeronauts, Pilatre du Rozier
and the Marquis d'Arlandes, made an ascent November 21, 1783,
and crossed Paris in a montgolfler.
But the history of gas balloons is rich in data applicable to
our subject.
The first of December in this same year of 1783, the physicist
Charles, who had just invented the hydrogen balloon, tested his
invention under conditions much more stirring and dangerous than
the two brave aeronauts just mentioned. This ascension, as we
know, was divided into two periods: Charles, who left the Tuileries
at 1:45, landed at 3:30 in the plain of Nesles; he let his companion
Robert get out of the basket; then, lightened, his balloon rose
again with extraordinary speed. In less than ten minutes he rose
over 1500 fathoms; the barometer stopped at 18 inches, 10 lines.
The story 1 of the clever physicist, filled with justifiable en-
thusiasm, shows ,him as "questioning his sensation, listening to
himself live, and having no disagreeable feeling in the first mo-
ment." But soon:
In the midst of the inexpressible rapture of this contemplative
ecstasy, I was recalled to myself by a very extraordinary pain in the
interior of my right ear and in the maxillary glands; I attributed
171
172 Historical
it to the expansion of the air contained in the cellular tissue of the
organ, as well as to the cold of the surrounding air .... I put on a
woolen hood which was at my feet; but the pain vanished only when
I reached the ground.
This marvellous invention thrilled the whole world; the most
ardent illusions about the practical utility of balloons were cher-
ished. Among the strange ideas produced by these experiments
in which man took possession of the air for the first time, one of
the most curious is that which, less than a year after the first
ascent, inspired a thesis sustained in 1784 before the Faculty of
Medicine of Montpellier. Louis Leullier-Duche, its author,2 had
the idea of using balloon ascension as a treatment of diseases.
"The effect," he said, "will be triple: motion, cold, change of
air."
He insists especially upon this last point:
The essential part of air is for man the dephlogisticated air
(oxygen). Now in what proportion is it united with the phlogistic in
the different regions of the atmosphere? Chemists have not deter-
mined. But as the phlogistic is lighter, there must be more of it at
a very great height .... The neighborhood of the earth is the proper
region of the dephlogisticated air. But we cannot doubt that it is
polluted there by different emanations of volatile bodies. And so, in
that part of the atmosphere which is the region of dephlogisticated
air, the latter is purer the further we go from the surface of
the earth. Moreover, as it is colder, the dephlogisticated air is accu-
mulated and condensed there.
Leullier-Duche attributes the strongest curative virtues to oxy-
gen, and considers that it acts even on generation and death:
Births at Montpellier coincide with the spring months and deaths
with the autumn months; during the spring, the atmosphere is more
laden with dephlogisticated air which the growth of plants produces,
and during autumn their putrefaction releases a greater quantity of
inflammable or phlogistic air (he refers to nitrogen by this double
name).
Leullier-Duche then proposes to use balloons in the treatment
of intermittent, pestilential, or nervous fevers, rickets, scurvy,
hysteria, chlorosis, melancholy, slow healing sores, etc.
We have seen that the inventor of the hydrogen balloon, in the
first and only ascent which he made, experienced painful sensations
when he had risen rapidly to a height of about 3000 meters. It
was simply a matter of the expansion of the gases of the middle
ear, gases which on account of the speed of the ascent had not
had time to escape by the Eustachian tube. More serious symp-
toms were soon to be observed.
Balloon Ascensions 173
On the 12th of Brumaire in the year VII (see the Moniteur, p.
173), Testu-Brissy, mounted on a horse, rose to a considerable
height.
In a little book,' "dedicated to childhood", a curious engraving
represents him on horseback on a platform supported by a cylin-
drical balloon. After some details about the ascent of the
adventurous aeronaut, the author, who says she knew him,
declares that:
The purpose of the scientist was attained; he discovered that at
a degree of elevation where he himself was not at all affected, the
blood of large quadrupeds, apparently less fluid than that of man,
was forced out of the arteries and ran out through the nose and ears.
Satisfied with this observation, he descended from the considerable
height to which he had risen, and gave account of his expedition to
the Institute with modest simplicity. (P. 95.)
One can hardly attach much importance to this tale.
Two years after the ascent of Charles, Blanchard, an aeronaut
who died poor and obscure after enjoying prodigious popularity,
whose statement, it is true, cannot carry much weight, claimed to
have risen November 20, 1785, from Ghent, to a height of 32,000
feet (10,400 meters) :
I rose with a rupture of equilibrium of 35 pounds .... In less
than two minutes, I was more than 4500 feet from the earth ....
The expansion of the inflammable air was such .... that I mounted
to an incredible height, which according to the record of my instru-
ment was 32,000 feet from the earth ....
I sailed in the immensity of the air at the mercy of the winds,
experiencing a cold which no mortal ever felt in the severest climates.
Nature grew languid, I felt a numbness, prelude of a dangerous sleep,
when rising in spite of my lack of strength, I called upon my courage,
entered my balloon, and with the handle of my flag .... I broke
the lower pole in pieces. (P. 7.)
The result of this maneuver was a rapid fall, which ended
happily after a series of curious incidents.
Blanchard announced his ascent briefly in a letter,5 addressed
to the Journal de Paris. It is evident that he mounted very high;
but his observation or his calculation was certainly wrong.
The astronomer de Lalande, who also dabbled in aerostatics,
appeared quite doubtful. He wrote to" the publishers of this
curious extract to refute the assertions of the vain aeronaut:
174 Historical
Paris, December 7, 1785.
Gentlemen:
Probably a mistake slipped into the article which you published
on the fifth of this month in regard to the ascent of M. Blanchard,
made November 21 near Ghent; it says that he rose to 32,000 feet,
which would make 5333 fathoms; the greatest height reached hitherto
is 2434 fathoms, and the great expansion of the air would probably
make it impossible to rise to or to breathe at a height which is more
than double that .... At 2430 fathoms height the barometer is at
only 16 inches. M. de la Condamine observed it at 15 inches 11 lines,
but no man has seen it lower. If one could rise to 5441 fathoms, the
barometer would stand at only 8 inches, and it is probable that hem-
orrhage and death would soon be the result.
De Lalande.
There follows a table given by de Lalande, indicating the rela-
tions between the barometric pressure and the altitude:
27
inches
158 fathoms
12 inches
11 inches
10 inches
3679 fathoms
4057 fathoms
4472 fathoms
16
inches
2430 fathoms
9 inches
4929 fathoms
15
inches
2710 fathoms
8 inches
5441 fathoms
14
inches
3010 fathoms
7 inches
6021 fathoms
13
inches
3332 fathoms
By the way, Lalande reproduces this table in the Yearbook of
the Bureau of Longitudes for the year 1805, then he adds:
The last numbers will probably be eternally useless; human beings
will never see the barometer at 11 inches, unless, by artificial means,
they succeed in giving air to the lungs and lessening the pressure of
the inner air. (P. 94.)
In the Yearbook of 1806, the remark about the impossibility of
reaching 11 inches is suppressed. The only statement is:
The last numbers are probably useless: M. Gay-Lussac went only
to 3584 fathoms. (P. 99.)
Prudent correction, for 11 inches correspond according to
Lalande to 4057 fathoms (7907 meters) , a height far surpassed
since then, as we shall see, by Glaisher and Coxwell and by Gaston
Tissandier.
But let us return to Blanchard; he did not consider himself
conquered, and replied haughtily in the Journal de Paris:7
Gentlemen:
If I have not replied sooner to the letter written you by M. de
Lalande about a so-called error in regard to my ascent at Ghent, in
which I say I rose to the height of 32,000 feet, it is not for want of
material; I shall not reply even today, intending to discuss his opin-
Balloon Ascensions 175
ion at greater length in the collection of journals of my ascents which
I intend to give the public. The nature of your paper, gentlemen,
would not permit me so long a discussion.
M. de la Condamine, says my illustrious antagonist, is the only
man who has observed the barometer at the lowest level, and he
observed it, he adds, at 15 inches 11 lines. It would be of no use to
remind him that I said that I had seen it at 14 inches in my ascent
from Lille with the Chevalier de l'Epinard, and lower yet in England,
because, words not being proofs, he would be just as incredulous in
the matter. Knowing all M. de Lalande's superiority, I shall take
care to contend with him only with victorious arms; and as facts
sometimes give the lie to the most careful calculations, I limit myself
now to inviting him, as I have just done in a personal letter, to do
me the honor of accompanying me in my next ascent; he will then
be convinced that the best arguments have no effect against the cer-
tainty of a fact. Yours, etc.
Blanchard,
Citizen of Calais, pensioner of the King.
We know that de Lalande replied to the challenge.
One should read in the Journal de Paris,8 his curious corre-
spondence with Blanchard on this subject. On the 8th of Thermidor
in the year VII, they both ascended with the famous flotilla of
five balloons invented by the celebrated aeronaut. They hoped, by
making use of currents, to go as far as Gotha "to see with delight"
said Lalande, "a prince and a princess who, by their learning and
their zeal for the sciences, give an example to everyone"; but alas!
one of the balloons burst, and the astronomer and the citizen of
Calais fell ingloriously into the Bois de Boulogne.
But let us drop stories lacking precision and perhaps truth.
We enter the domain of scientific attempts with the remarkable
ascents of Robertson and, soon after, of Gay-Lussac.
The most important ascent of the French physicist Robertson9
took place at Hamburg, July 18, 1803. He started at 9 o'clock in
the morning, accompanied by M. Lhoest, his colleague and com-
patriot; the barometer marked 28 inches, the Reamur thermom-
eter 16°:
During the different tests with which we were busied, we felt
an uneasiness, a general discomfort; the buzzing in the ears from
which we had for some time been suffering increased still more as
the barometer dropped below 13 inches. The pain we felt was some-
thing like that which one feels when he plunges his head below
water. Our chests seemed expanded and lacked resilience, my pulse
was hurried; that of M. Lhoest was less so: like mine, his lips were
swollen, his eyes bloodshot; all the veins were rounded out and stood
up in relief on my hands. The blood had rushed to my head so much
that I noticed that my hat seemed too small. The cold increased
176 Historical
considerably; the thermometer then dropped quickly to 2°, and stopped
at 5V20 below freezing, while the barometer stood at 12 and 4/100
inches. Hardly was I in this atmosphere when the discomfort
increased; I was in a mental and physical apathy; we could hardly
ward off the sleep which we feared like death. Distrusting my
strength, and fearing that my companion would succumb to sleep, I
had fastened a cord to my thigh and to his; the ends of this cord
were in our hands. It was in this state, not much adapted to delicate
experiments, that I had to begin the observations that I was planning.
(Vol. I, p. 70) ... .
At this elevation, our state was that of indifference: there, the
physicist is no longer sensitive to the glory and the passion of dis-
coveries; the very danger which results from the slightest negligence
in this journey hardly interests him; it is only by the aid of a little
fortifying wine that he succeeds in finding intervals of mental clarity
and power.
As I wish to omit nothing that can cast light on the functions
of the animal economy and the operations of nature at this elevation,
I ought to mention that when the barometer was still at 12 inches,
my companion offered me bread: I made vain efforts to swallow it,
but never could succeed. If one considers carefully the state of the
surrounding atmosphere, the great rarity of which offered only a
slight resistance to my expanding chest; if one considers the small
quantity of oxygen contained in the gas in which I was floating, one
can believe that my stomach, already filled by a denser gas which was
impoverished by the loss of oxygen, was in no state to receive solid
food and still less to digest it. I must add that the natural excretions
were checked in my friend and myself during the five hours of the
journey, and that they were not resumed until three hours after our
return to earth ....
Seventh experiment. I had taken along two birds: at the moment
of the experiment I found one of them dead, no doubt on account
of the rarefaction of the air; the other seemed drowsy. After placing
him on the edge of the basket, I tried to frighten him to make him
take flight: he beat his wings, but did not leave his place; then I left
him to himself, and he fell perpendicularly with extreme speed. There
is no doubt that birds could not support themselves at this elevation.
(P. 76) ... .
One can estimate the height of the balloon, taking account of
all the corrections, at 3679 fathoms (7170 meters).10 (P. 83.)
The number of March 16, 1876, of the journal Les Mondes says
on this subject:
If, in one passage of his account, Robertson says that he mounted
to 7170 meters, in another he says only 7075; calculating by the
present tables of the Yearbook of the Bureau of Longitudes on the
data of temperature and pressure registered by Robertson, we find
only 6881 meters for the maximum height. (Ch. Boissay.)
Robertson sent the account of his ascent and of the experi-
ments in physics which he performed during it to the Galvanic
Balloon Ascensions 177
Society; a report " was made from which we extract the following
passage:
We have known for a long time that an animal cannot pass with
impunity from an atmosphere to which he is accustomed to one much
denser or much rarer. In the first case, he suffers from the weight of
the outer air, which has an excessive pressure; in the second case, the
liquids or elastic fluids which are part of his system, since they are
undergoing less than the usual pressure, expand and stretch the
surrounding tissues. In both cases, the effects are almost the same,
uneasiness, general discomfort, buzzing in the ears, and often hemor-
rhages; the experiment of the diver's bell long ago indicated to us
what would happen to aeronauts. Our colleague and his travelling
companion experienced these effects with great intensity; their lips
were swollen, their eyes bloodshot; the rounded veins stood out in
relief on their hands, and — a very astonishing fact — they both dis-
played a reddish brown complexion which surprised those who had
seen them before their ascent.
This distension of the blood vessels, in their farthest ramifications,
must necessarily produce a hindrance, a constraint in all the muscular
movements; and it is mainly to this cause that I think we should
attribute the vain efforts made by our colleague to swallow the bread
which his companion gave him when they were still at a height
marked by 12 inches on the barometer. (Mem., Vol. I, page 106.)
An aeronaut who was celebrated for being the first to descend
from a balloon in a parachute (October 29, 1797), Jacques Garn-
erin, tried to take from his rival Robertson the honor of the highest
ascent. As the following extract from the Journal de Paris 1J
proves, he claimed to have risen to 4200 fathoms (8186 meters).
In the interest of the sciences and the arts, which barbarians have
mutilated, M. Garnerin writes from St. Petersburg to Paris the account
• of the aerial journey which he undertook at Moscow the third of last
October, in which he rose exactly to the height of 4200 fathoms,
without having experienced any symptom other than hemorrhage of
the nose, and a little discomfort from the cold. Happy opportunity
to entertain the public with his quarrels with M. Robertson, whom he
calls "the aeronaut of Hamburg", and whose powers of observation
and whose truth he questions! "I rose," says M. Garnerin, "521 fathoms
higher than the aeronaut of Hamburg, and I did not notice that
matter lost weight, nor did I see the sun without brilliancy, nor the
sky without azure. I felt neither an extraordinary apathy, nor diffi-
culty in swallowing, nor a desire to sleep, etc "
Nothing seems less authentic than the statement of Garnerin;
the data which we shall presently report show that at the height
which he says he reached he would have experienced very serious
physiological disturbances.
178 Historical
In this same year, a very dramatic ascent took place at Bologna.
Count Fr. Zambeccari, of Bologna, Dr. Grasetti, of Rome, and
Pascal Andreoli, of Ancona, left during the night of the 7th-8th
of October, 1803. They had spent the day in inflating their balloon,
which measured 14,000 cubic feet, and intended to start the next
day; but they had to hurry on account of the rioting and shouts
of the populace of Bologna. The balloon rose with extreme rapid-
ity, and they soon reached such a height that Zambeccari and
Grasetti, overcome by the cold and exhausted by a series of
vomiting, fell into a sort of torpor accompanied by a profound
sleep. The brief account, inserted in the Annales de Gilbert,1 '■
tells their sufferings and misfortune as follows:
Andreoli, who had retained use of his senses, could not read the
barometer because the candle which they had brought in a lantern
had gone out. About 2:30 in the morning, the balloon began io
descend, and Andreoli heard distinctly the noise of waves breaking
on the coast of Romagna. He awoke his companions .... The basket
and the balloon fell into the Adriatic Sea with such force that the
water dashed up around them to the height of a man. The aeronauts,
covered with water, in great haste threw out a bag of sand, their
instruments, and all that the basket contained.
Then the balloon again rushed rapidly into the air. They tra-
versed three strata of clouds, and their clothes were covered with a
thick layer of ice; the air was so rarefied that they could hardly hear
each other. About three o'clock the balloon descended again.
The melancholy German pamphleteer Kotzebue,14 during his
journey to Italy, called on Zambeccari, this man "whose eyes are
thoughts". The daring aeronaut gave him a detailed account of
this terrible ascension of October 7-8, in which he nearly perished:
I rose at midnight .... Suddenly we mounted with inconceivable
speed.
We could observe the barometer only by lantern light, and that
very imperfectly. The unendurable cold which reigns in the region
to which we had risen, the exhaustion I felt from lack of food for 24
hours, the grief which overwhelmed my soul, this whole combination
caused complete torpor and I fell on the bottom of the basket in a
sort of sleep like death. The same thing happened to my companion
Grasetti. Andreoli was the only one who remained awake and well,
no doubt because his stomach was full and he had drunk rum abun-
dantly. In fact, he too had suffered greatly from the cold, which was
excessive, and for a long time made vain efforts to awaken me.
Finally he succeeded in getting me to my feet, but my ideas were
confused; I asked him, as if I had been dreaming: "What's the news?
Where are we going? What time is it? What is the direction of the
wind?"
It was two o'clock. The compass was ruined, consequently it was
Balloon Ascensions 179
useless to us; the candle in our lantern could not burn in an air so
rarefied, its light grew dimmer and dimmer, and finally went out.
(Vol. IV, p. 301-303.)
They then fell into the sea; then having thrown out everything
in their basket, they rose again:
With such rapidity, to such a prodigious height, that we could
hardly hear each other even when we shouted; I was sick and vomited
considerably. Grasetti had the nose-bleed; we both had short respira-
tion and an oppression in our chests. As we were wet to the
bone when the balloon took us into the higher strata, the cold seized
us rapidly and we were covered in an instant with a layer of ice. I
cannot explain why the moon, which was in its last quarter, was in
a line parallel with us, and seemed red as blood. After rushing
through these immense regions for a half-hour and being carried to
an immeasurable height, the balloon began to descend slowly, and we
fell once more into the sea; it was about four o'clock in the morning.
(Vol. IV, p. 305.)
The unfortunate aeronauts fell into the Adriatic and remained
there, the playthings of the winds and the waves, until 8 o'clock,
when a bark picked them up, not without great difficulties. Their
feet and hands were frozen, and Zambeccari had to have three
fingers amputated.
The following year on June 30, Robertson 15 made a new ascent,
accompanied by the Russian physicist Sacharoff; but their barom-
eter went to only 22 inches and they had no special experiences.
This same year of 1804, two young physicists, Biot and Gay-
Lussac,111 were given by the Institut de France a scientific mission
in the air. They were particularly to investigate variations of
magnetic power, which de Saussure thought he had observed on
the col du Geant.
The two scientists left on the 6th of Fructidor, at ten o'clock
in the morning, from the garden of the Conservatoire des Arts.
As they did not rise above 4000 meters in a temperature of +10°,
they felt no serious physiological disturbances. So they said only a
few words on this subject:
We observed the animals which we had taken along; they did
not seem to suffer from the rarity of the air; however the barometer
stood at 20 inches 8 lines, which gives a height of 2622 meters. A
violet bee, which we freed, took flight very quickly and buzzing left
us ... .
Our pulses were very fast; that of Gay-Lussac, which is ordi-
narily 62 per minute, was 80; mine, which is usually 89, was 111. This
acceleration then was felt by us both in about the same proportion.
180 Historical
However, our respiration was not at all affected; we felt no discom-
fort, and our situation seemed to us extremely agreeable ....
We observed our animals at all heights; they did not seem to
suffer at all. As for us, we felt no effect, except this acceleration of
the pulse rate of which I have already spoken.
There follows the account of what happened to a greenfinch
and a pigeon, freed at 3400 meters; the pigeon opened its wings
and let itself fall describing circles like the large birds of prey.
Gay-Lussac 17 started alone some days after, and rose much
higher than the first time. The symptoms of a physiological nature
were quite endurable; he speaks of them thus:
When I had reached the highest point of my ascent, 7016 meters
above sea level, my respiration was noticeably hampered; but I was
still far from experiencing such severe discomfort as to wish to
descend. My pulse and respiratory rate were much accelerated; and so,
breathing very frequently in a very dry air, I was not surprised to
find my throat so dry that it was painful for me to swallow bread . . .
These are all the inconveniences I experienced. (P. 89.)
In regard to this account Robertson made an observation which
is interesting because it shows what cause he assigns to the
phenomena which he experienced himself:
I do not think that there is a professor of physics who has not
spoken to his hearers of the weight of the column of air which corre-
sponds to the body surface of a man, and who has not shown that
this enormous weight is made imperceptible to the body by the
equilibrium established between the pressure of the outer air and the
reaction of the elastic fluids which are part of its inner system. There
is none who has not demonstrated what the effects of the rupture
of this equilibrium would be. (Mem., vol. I, p. 107.)
But nothing justified Robertson in drawing from these remarks
the strange conclusion which follows:
I do not think that M. Biot has changed all that. No one can
refuse to conclude that the effects experienced by M. Lhoest and my-
self, then by M. Sacharoff, are anything but very reasonable; while
those experienced by MM. Biot and Gay-Lussac are so contrary to
ours that they need to be explained. Now the only explanation
possible is that these aeronauts did not rise high enough or that they
rose so slowly that there was no rupture of equilibrium for them,
otherwise one cannot see what could have kept them from experi-
encing the effects which are the inevitable consequences. (Mem., vol. I,
p. 108.)
This doubt unnecessarily cast upon the truth of the observa-
tions of scholars like Biot and Gay-Lussac should have had just
Balloon Ascensions 181
reprisals, and it had much to do with the undeserved discredit
which has since fallen upon the statements of Robertson.
The ascent of Gay-Lussac had a well deserved fame. But people
went too far in passing over in complete silence those which had
preceded it. Robertson complained justly that the role which he
himself had previously played had not been recognized:
M. Biot printed in his treatise on physics and repeats in his
courses in the College de France that M. Gay-Lussac rose to the
greatest height that man had reached up to that time. This assertion,
though false, is believed by the youth of today, because I have no one
who can say every year to some hundreds of auditors that I had risen
to 3630 fathoms more than a year before the ascent of Gay-Lussac;
and the time will soon come when no one will know or remember that,
before the ascent of MM. Biot and Gay-Lussac, I had made one like it,
and like theirs, in the interest of science, but during which the air of
those high regions had been less hospitable to me than to those gentle-
men. (Mem., vol. I, p. 117.)
A few years after, in August, 1808, Andreoli, one of the com-
panions of the unfortunate Zambeccari, rose from Padua, and
reached, if we are to believe him, a height much greater than that
which his predecessors had attained. The correspondent of the
Journal de Paris,18 who tells the story, seems to give little credence
to the account of the Italian aeronaut, a really very extraordinary
account, in which we do not know whether to be more astonished
at the ascent or the descent of the daring and lucky aeronauts:
Italy. Padua, April 23, 1808.
M. Andreoli undertook yesterday in this city an aerostatic journey,
which was not very lucky and the account of which arouses unpleas-
ant doubts among well-informed people as to the veracity of the
physicist. According to this really curious story, which people in
Paris may perhaps ridicule, M. Andreoli, accompanied by M. Brioschi,
rose at 3:30 in the afternoon, in the presence of a great number of
spectators. The barometer having dropped to 15 inches (to 15 inches!
Are they quite sure of what they say, and do they know how prodi-
giously rarefied the air should be and really is at that height? And in
that case, how would the two travellers have breathed?) at this eleva-
tion, Brioschi began to feel extraordinary palpitations, without, however,
noticing any painful change in his breathing: the barometer dropping
next to 12, he felt himself overcome by a gentle sleep, which soon
became a real lethargy (they do not say how M. Andreoli felt, and
how he resisted the powerful narcotic which overcame his companion).
The balloon kept rising and when the barometer was at about 9
inches (that is, a height much greater than that of the highest of the
Cordilleras) Andreoli perceived that it was completely expanded and
that he could not move his left hand. The mercury, continuing to
descend, registered 8V2 inches. Then the balloon exploded with a loud
182 Historical
report and began to descend rapidly (I believe it), and then M.
Brioschi awoke (not without terror). The fall took place at the castle
of Enganca, not far from the tomb of Petrarch and the city of Acqua,
12 miles from Padua; and the most marvellous thing about this story,
which was so marvellous from end to end, is that the travellers, no
doubt protected by a geni out of the Thousand and One Nights, did
not experience the slightest harm, not even the least scratch. Surely
that is a miracle which should disconcert all the calculations of ordi-
nary physicists. However it may be, the travellers took post horses,
and reached Padua at 8:30 to receive congratulations which such a
prodigious success deserved on every score.
I should note here that the celebrated English aeronaut, M.
Glaisher,19 seems disposed to give credence to these extraordinary
data; he calls attention to the fact that Andreoli, accustomed to
ascents, suffered much less than his companion. And as to the
possibility of surviving such a terrible fall, he discusses it with
authority and admits it without great hesitation. (P. 161.)
August 29, 1811, two Englishmen, Beaufoy and Sadler,-" made
an ascent in which they did not rise above 6000 feet, and which
holds no interest for us except the sensation felt by Beaufoy "of
a slight pressure in the ears and a little deafness", and especially
the strange explanation of it which the traveller gives: he attrib-
utes this effect to "the dampness resulting from not wearing a
hat during the trip." (P. 296.)
April 26, 1812, the widow of Blanchard, who was to die so
miserably July 6, 1819, on a roof in the Rue de Provence, made
an ascent at Turin in which she claimed to have risen to a very
great height. The Journal de Paris 21 gave an account of it in the
following words:
She had taken a barometer with her .... At 15 inches 6 lines,
the cold was icy; at 14 inches 1 line, Mme. Blanchard said she had
experienced a lessening of the cold; at 12 inches 11 lines, she felt a
palpitation of the artery near the outer angle of the left eye and a
sort of trembling of the lower lid of the same eye. At 12 inches 3
lines, she had a severe nosebleed.
A few minutes later, the barometer marked 10 inches 3 lines,
which was its lowest point .... This indicates that the highest
elevation of Mme. Blanchard was 3900 fathoms (7600 meters); at this
height the cold was unbearable, the Reaumur thermometer was 17°
below freezing ....
The color of the sky was almost black .... The sun did not have
its usual rays and its diameter seemed much smaller than when
observed from the earth. A moment after these observations, the
thermometer dropped another degree, and Mme. Blanchard, almost
stiff with cold, decided to descend.
Balloon Ascensions 183
Robertson expressed some doubts about the exactness of Mme.
Blanchard's barometric readings. The note he sent to the Journal
de Paris -- contains details about the sufferings which he and
Lhoest had experienced in their ascent of July 1803, which are not
included in the account we quoted above:
The elevation to which you state that Mme. Blanchard rose lately
at Turin must surprise your readers all the more as it must be
regarded as the last degree of human temerity .... First I must admit
that I think it impossible for anyone, with an aerostat of 20 feet
diameter, which Mme. Blanchard ordinarily uses, to rise high enough
to make the mercury drop to 10 inches ....
When one reaches the elevation of 3600 fathoms, one yields grad-
ually and unconsciously to a lethargic sleep; the mental faculties
succumb long before the physical faculties. First one has no memory,
no cares for the present or the future; one forgets to supervise the
aerostat; soon a soft and gentle sleep, which one cannot resist, lulls
all the members and holds the aeronaut in a complete asphyxia, which
no doubt is fatal if it is prolonged ....
In July, 1803, I made an ascent at Hamburg with M. Lhoest ....
The barometer dropped to 12 inches and some lines (while we were
still in possession of our faculties). The sky seemed to us to be brown;
the sun lacked brilliance; we could gaze at it without being dazzled;
we had a slight hemorrhage, and experienced all that Mme. Blanchard
has just mentioned. We succumbed to sleep in this ascent; but the
lower part of the balloon .... released the gas which was driven
out by expansion. We roused from this torpor simultaneously and
suddenly, without being able to tell what had happened, except that
there had been a break in the continuity of our ideas.
Eugene Robertson,-3 one of the sons of the celebrated aeronaut,
rose on October 16, 1826, from Castle Garden in New York, to
21,000 feet (6400 meters) ,-* in a balloon of 16,000 cubic feet,
inflated with hydrogen:
Respiration was painful and difficult, the faculties were blunted,
the cold unbearable, especially in the hands. (Therm, at 21 °F.)
February 12, 1835, this same aeronaut 25 rose from Mexico to a
height of 5928 meters. He examined from close at hand the crater
of the former volcano the Chicle and rose "above a nursery of
mountains."
The famous English aeronaut Green, who made, according to
Glaisher,20 more than fourteen hundred ascents, certainly rose
several times to great heights; but he seems to have been rather
careless about exact measurements, and his figures show evidence
of great exaggeration.
One of his ascents, which took place in 1821, is curious because
184 Historical
of the nature of the gas with which he inflated his balloon; he
used oxide of carbon which took him to 11,000 feet.JT But this
does not concern our subject.
April 20, 1831, Dr. Forster 28 with Green made a balloon trip
which did not exceed an elevation of 6000 feet, a height at which
they remained for four hours. Their physiological observations
referred only to the phenomena of deafness which attack mountain
travellers and aeronauts. Forster considers them as having very
different causes in the two cases, due in the first to a feeling of
fullness in the ears, and in the second to a real weakening of the
hearing.
The extravagant exaggeration of Green's statements begins
to appear in a note of the publisher of Froriep's Notizen,29 which
reports naively that Green had made 226 ascents, in which he had
several times gone above 6000 fathoms, without experiencing diffi-
culty in breathing.
The story which Green30 himself gave of the catastrophe by
which, September 27, 1836, his companion Cocking lost his life,
indicates a height which perhaps should not be considered
accurate. We know that Green played a very sorry role in this
mad adventure. Cocking had made a parachute wrong side out,
the absurdity of which no one could doubt; Green consented
nevertheless to take it along. The unhappy Cocking unfastened
his parachute just as the balloon reached the height of 5000 feet;
he fell like a stone. At the same time, the balloon, freed of his
weight, darted upward to great heights:
We rose then with such rapidity that we were almost suffocated;
with great difficulty I controlled my senses enough to observe the ba-
rometer; but M. Spencer observed that the mercury stopped at 13.20,
which gives an elevation of 24,384 feet (7430 meters), or about 4*4
miles.
But that is nothing beside what he told of an ascent made with
Rusch; the pathologist Henle u reports this prodigious statement
as a very simple thing, and without making any comment:
In his balloon ascents, Green says he never experienced any
acceleration of the pulse or of the respiration, except when he rose
rapidly after throwing out ballast.
In 1838 he rose with Rusch to the height of 27,136 feet (8268
meters), where he saw the mercury drop to 10.32 inches; he passed
through the first 11,000 feet (3350 meters) in 7 minutes, without any
inconvenience except those mentioned above. (P. 386.)
Tall tales are useless! An Italian aeronaut claimed to have
Balloon Ascensions 185
surpassed even the fabulous height that the English balloonist
said he had reached. We read, in fact, in the Proceedings of the
Academy of Sciences of Paris: 32
M. Bonafoux writes that on the occasion of the marriage feast of
the hereditary Prince of Savoy, M. Comaschi made a balloon ascent
at Turin, in which, if there was no mistake in the barometer readings,
M. Comaschi rose to 9474 meters above sea level; but the difference in
temperature would seem to indicate a lesser height.
The story of Hobard, if it does not give information of great
precision, at least appears credible; it is inserted in the Courrier
francais of October 9, 1835:
August 17, 1835, an aeronaut, M. Hobard, ran the greatest risks
in an ascent which he made at Lynchburg, in Virginia; he mounted
at seven o'clock in the evening, and in less than an hour landed about
13 leagues from the city. M. Hobard in his account says that a few
minutes after his departure he lost sight of the earth completely. At
half past seven he made his last observation and judged that he was
more than a league high. He saw then two meteors, one in the north
and the other in the west; the latter seemed to be approaching rapidly,
but it disappeared suddenly, to the great satisfaction of M. Hobard,
who feared that it would set his balloon on fire. Shortly after, a
squall seized the balloon and whirled it aloft to a height which the
aeronaut estimated as not less than 26,000 feet (7925 meters), judging
by the difficulty of breathing and the entire loss of hearing. He wished
to let gas escape by opening the valve; but not being able to hear,
he could not judge, as usual, the escape of the gas by the noise it
makes as it issues. He saw nevertheless that the balloon was not
deflating much, and he feared it would burst; he feared also that some
of his veins would burst, since the rarefaction of the air had made
them dilate greatly. The first of his fears was soon realized. Without
entirely bursting, the balloon split above and rapidly deflating de-
scended with great speed. Happily for M. Hobard, the fall of the
balloon was broken by a young fir whose flexible trunk protected
him from the terrible shock he would have experienced. However he
was thrown out of the basket and considerably bruised, but what were
a few contusions in comparison with the cruel death he expected! M.
Hobard based his estimate that his greatest elevation was 26,000 feet
on the fact that the rarefied air had affected his organs in a more
painful way than was experienced by aeronauts who had risen to
25,000 feet, the maximum height hitherto reached in balloon ascen-
sions.
We must refer to the memorable ascent of MM. Barral and
Bixio, July 27, 1850, to find scientific certainty and precision. But
from our point of view, this ascent, so useful to meteorology, has
only moderate interest. In fact, under the influence of a barometric
pressure of 315 mm., corresponding to a height of 7016 meters, in
186 Historical
spite of a temperature of 39° below zero, the two brave travellers
experienced no physiological symptom which attracted their atten-
tion: "Our respiration", they merely said, "was not at all
affected." 13
Two years later, ascents no less important from the scientific
point of view were made in England by M. Welsh:34
In July, 1852, the Committee of the Kew Observatory decided to
institute a series of balloon ascensions for the study of the meteor-
ological and physical phenomena which require the presence of an
observer in the upper strata of the atmosphere. (P. 311.)
J. Welsh, who took Nicklin as companion, was charged with
the scientific part; the control of the balloon was entrusted to the
celebrated aeronaut Green. The first ascent took place August 17,
the aeronauts rose to 19,510 feet (5945 meters) ; in the second
(August 26) , they rose only to 19,100 feet (5820 meters) ; and in
the third, only to 12,640 feet (3850 meters) . But on November 10,
in one hour they reached 22,930 feet (6987 meters) and remained
more than 10 minutes above 20,000 feet; the descent took place
with extraordinary rapidity:
At this height, much greater than all the others we had reached
previously, the effects of lowered pressure began to be felt more. M.
Green and I experienced very great difficulty in breathing, with
increased panting and fatigue after the slightest exercise. (P. 320.)
At much lower elevations still, a celebrated English meteor-
ologist, M. Glaisher, noted considerable modifications in respir-
ation and circulation.
The ascents of M. Glaisher constitute the finest series of aerial
journeys ever undertaken with a scientific purpose. Some of them
took him to very great heights, and one will forever remain
famous, that in which he nearly died from the decompression. I
am quoting from Voyages acriens 3B the following data which
have a bearing on our subject.
The first ascent took place June 30, 1862; Glaisher and his
balloon engineer Coxwell reached 8000 meters:
Between the heights of 4700 and 5900 meters, the thermometer
marks 6° above zero. . . . The palpitations of my heart are beginning
to become apparent, and my breathing is no less disturbed, my hands
are growing blue, and my pulse rate, becoming feverish, is 100 beats
per minute.
At 6168 meters, we are in a stratum at zero degrees .... my
pulse is growing still quicker, and I have increasing difficulty in
reading the instruments; I feel a general discomfort, like seasickness,
Balloon Ascensions 187
although the balloon is not rolling or pitching .... The blue of the
sky has become purer. (P. 47.)
The English edition of the work quoted above,:!,i which M.
Glaisher published in 1871, gives quite a different account of the
symptoms experienced by the learned aeronaut. In the first place,
the date of this ascent is given as July 17 instead of June 30:
At the height of 18,844 feet (5740 meters), my pulse beat 100
times a minute; at 19,435 feet (5920 meters), I noted the beating of
my heart; the ticking of the chronometer seemed very noisy and my
respiration began to be affected; my pulse was still faster, and 1
read the instruments with growing difficulty; the palpitations of tho
heart were violent. My hands and my lips were a deep bluish color,
but not my face .... At 21,792 feet (6640 meters) I felt a sort of sea-
sickness, although the balloon did not roll or pitch; I was so sick
that I was unable to examine the instruments .... The sky seemed
a very dark blue. (P. 44.)
Second Ascent, August 18, 1862. The travellers reached 7100
meters, the highest point of the ascent:
I felt the pulse of M. Coxwell," which was only 90 per minute,
whereas mine was increasing rapidly. From 100 it went to 107 and
then to 110, without that of my companion changing appreciably ....
As we descended we heard another clap of thunder roaring in the
clouds which we were rapidly approaching. Is it the increasing speed
of our descent that oppresses me? Is it the electric tension whose
increase disturbs the hidden sources of life? .... I do not know, but
I experience a sudden distress, a sort of nervous trembling. Happily,
after a minute of anguish, a wonderful spectacle helps me triumph
over this fleeting swoon. (Voyages acriens, p. 57.)
At last came the famous ascent of September 5, 1862; it is the
third. The ascent from Wolverhampton took place at 1:03 in a
temperature of +15°. At 1:34, the aeronauts had reached an alti-
tude of about 5200 meters; the temperature is —9°; there no
longer is water vapor in the air. The first physiological disturb-
ances then appear:
At 1:34, I noticed that M. Coxwell began to be out of breath,
which is not surprising, because he was constantly occupied with
managing the balloon ....
At 1:39, we reached the height of 6437 meters (the altitude of
Chimborazo) .... We threw out sand .... ten minutes were enough
for us to rise to the height of Dawalagiri; the temperature had fallen
to —18.9° ....
Up to this time I had taken my observations without difficulty,
whereas M. Coxwell, who was obliged to move about in his duties,
seemed weary. At 1:51, the barometer marked 11.05 inches. We found
out later, by comparison with the standard barometer of Lord Wrottes-
188 Historical
ley, that we should lessen this figure by a quarter of an inch. About
1:52, the dry bulb thermometer registered — 5°. Soon I could not see
the column of mercury in the wet bulb thermometer, or the hands of
a watch, or the fixed divisions of any of my instruments. I asked M.
Coxwell to help me get the figures which escaped me, but, because
of the rotation of the balloon, which had not ceased since we left the
earth, the cord of the valve was tangled. M. Coxwell had to leave
the basket and climb on the ring to untangle it. I observed the barom-
eter; I saw that it registered 10 inches, and that it was falling
rapidly. Its real height, taking care to subtract the quarter of an inch,
was 9 and % inches, which indicated a height of 29,000 feet (8838
meters). Shortly afterwards, I leaned on the table with my right arm,
which had had its full strength an instant before; but, when I wanted
to use it, I saw that it was no longer able to render me any service.
It must have lost its power instantaneously. I tried to use my left
arm, and found that it too was paralyzed. Then I tried to move my
body, and succeeded to a certain degree; but it seemed to me that I
no longer had any limbs; I tried once more to read the barometer, and
while I was making this attempt, my head fell on my left shoulder.
I stirred and moved my body again; but I could not succeed in raising
my arms. I lifted my head but only for an instant; it fell once more.
My back was leaning on the rim of the basket and my head in one
of its angles. In this position I had my eyes fixed on M. Coxwell,
who was in the ring. When I succeeded in sitting up, I was completely
master of the movements of my spine, and certainly still had great
control over those of my neck, although I had lost command of my
arms and my legs; but the paralysis had made new progress. Sud-
denly I felt incapable of making any movement. I vaguely saw M.
Coxwell in the ring, and I tried to speak to him, but could not move
my powerless tongue. In an instant, thick darkness seized upon me;
the optic nerve had suddenly lost all power. I still was perfectly
conscious and my brain was as active as while I am writing these
lines. I thought that I was asphyxiated, that I should make no more
experiments, and that death would seize me unless we descended
rapidly. Other thoughts were rushing into my mind when I suddenly
lost all consciousness, as when one falls asleep.
My last observation took place at 1:54, at 29,000 feet. I suppose
that one or two minutes passed, before my eyes ceased to see the little
divisions of the thermometers, and that about the same time elapsed
before my faint. Everything leads me to believe that at 1:57 I lapsed
into a sleep which might have been eternal. I was not able to move
when I heard the words temperature and observation. I perceived
that M. Coxwell was speaking to me and that he was trying to awaken
me; hearing and consciousness had then returned to me. I then heard
him speak louder, but I could not see him; it was much more impos-
sible to answer him or make a movement. He was saying to me:
"Try now, try." Then I vaguely saw the instruments and soon after-
wards surrounding objects. I rose and looked around me, as if I
were coming from a feverish sleep, which exhausted instead of resting
one. "I fainted", I said to M. Coxwell. "Certainly," he answered,
"and I nearly fainted too." I then pulled up my legs, which were
Balloon Ascensions 389
extended straight out, and took up a pencil to continue observations.
M. Coxwell told me that he had lost the use of his hands, which had
become black and on which I poured brandy.
He added that, while he had been in the ring, he had been seized
by an extreme cold and that icicles hung around the orifice of the
balloon, like a terrible candelabrum, worthy of the polar seas. When
he tried to descend from the ring, he could no longer use his hands,
and was forced to let himself slide on his elbows to get back into the
basket, where I was stretched out. He thought, seeing me on my
back, that I was resting, and spoke to me without getting an answer.
My face was serene and tranquil, without that anxiety which he had
noticed before climbing into the ring.
Seeing that my arms and my head were hanging down, M.
Coxwell understood that I had fainted. He tried to approach me, but
could not, feeling unconsciousness overcome him too. Then he wanted
to open the valve, but, having lost the use of his hand, could not
manage it. He could not have succeeded in controlling our course, if
he had not had the idea of seizing the cord between his teeth33 and
pulling it two or three times by shaking his head violently.
I resumed my observations at 2:07, and the first figures that I
registered were 292 mm. for the barometer and 18 degrees for the
thermometer. I suppose that 3 or 4 minutes passed from the moment
when I heard the first words of M. Coxwell to the moment when I
began again to read my chronometer and my other instruments. If
this is so, I returned to life at 2:04, and was completely unconscious
for seven minutes. (P. 59-64) ....
I felt no unpleasant result from my faint .... I walked eight
or nine miles after we had landed as easily as if nothing had happened
to me ....
I made my last observation at 8838 meters. [That is within two
meters of the height of the highest peak on the surface of the earth,
the Gaourichnaka of Nepal, at the foot of which the Brahmin pil-
grims who are seeking Nirvana come to die;39 one may say that no
human being ever could drag himself to this height following uneven
terrestrial surface, and in spite of their courage the brothers Schlag-
intweit did not aspire to mount there. However, I might have continued
my observations there, if the continued ascent of the balloon had not
taken me higher, where life is still more difficult.] When40 I fainted,
we were ascending at the enormous speed of 305 meters per minute,
and when I resumed my observations, we were descending at a speed
of 610 meters, double our speed of ascent; this circumstance permits
me to calculate with a certain exactness the height to which we had
really risen. (Voyages aeriens, p. 65.)
Calculations based both on the ascensional speed of the balloon
and on the temperature marked by a minimum thermometer have
led M. Glaisher to judge that the balloon had reached the height
of about 11,000 meters. The results of this calculation are, we
must say, evidently erroneous. We are surprised to see a scientist
of this caliber suppose that the balloon had a uniform speed in
190. Historical
ascending and descending, and solve by equations of the first
degree a problem which evidently depends on the second.
Everything leads us to believe that the balloon soon stopped
and soared for some minutes before descending.
I should mention a little experiment that is rather interesting:
We had taken with us six pigeons to toss into the air successively
at sufficient heights. We threw out the first at 4807 meters; he spread
out his wings but could not support himself and fell like a leaf of
paper.
The second, which was thrown out at 6437 meters, did not let
itself fall so easily; it whirled about, flying vigorously. Probably it
turned completely about each time it dived in spite of itself. Perhaps
by yielding to this strange waltz it found a way to resist the terrible
suction.
The third was thrown out before reaching the level of 8048
meters. It fell like a stone and disappeared rapidly. We kept the three
pigeons left for the descent, but we found that one of them was dead
in its cage and another was hardly better. When I took it from its
cage, it refused to fly away. Only after a quarter of an hour of rest
did it begin to peck at a bit of pink ribbon which was around its
neck. It was a carrier pigeon which, when once recovered, flew with
great rapidity in the direction of Wolverhampton. (P. 67) ....
Of all the pigeons thrown out during the journey, only one
returned to Wolverhampton, during Sunday (the fifth of September
was a Friday).
M. Glaisher made several more ascents in which he mounted
above 7000 meters (April 10, 1863, to 7300 meters;41 June 26, 1863,
to 7100 meters) ; in his accounts he says nothing at all of physi-
ological disturbances.
But he summarizes, in a separate section, the observations of
this sort which he made in these different ascents; I quote from
the English edition in which it is much fuller and more interesting
than in Voyages acriens:
The number of heart beats per minute increases with the altitude,
as does the number of inspirations: my pulse was generally 76 before
starting, about 90 at 10,000 feet, about 100 at 20,000 feet, and 110 at
greater heights; but the increase in the height is not the only element
on which the rate depends; the state of health has much to do with
it, as does the temperament of the different individuals.
The same thing is true of the color of the face; at 10,000 feet,
certain persons are of a flaming purplish red, while others are hardly
affected. At 17,000 feet, my lips were blue; at 19,000 feet, my hands
and my lips were a deep blue; at a height of four miles, one could
hear my heart beat and my respiration was much affected; at 29,000
feet, I became unconscious. From all observations one may conclude
that the effects of great heights are felt by everyone, but vary in the
same individual according to circumstances. (P. 92.)
Balloon Ascensions 191
M. Glaisher states that one soon becomes accustomed to the
influence of rarefied air, and cites his own experience in this
regard. He expresses hopes on this subject that show both keen
imagination and scientific understanding:
The diminution of pressure .... should act in a very special way
on persons who are journeying in the air for the first time. I can
make this statement from my own personal experience, which cer-
tainly has some value, for I have not always been able to ascend
without ill consequences to a height which ordinarily produces great
distress, and generally brings on discoloration of the hands and face.
I recall having caused great astonishment in a group of scientists by
stating that I was accustomed to rising to very lofty altitudes ■ without
turning blue. I am really convinced that I have become acclimated
to the effects of the rarefied air found at six kilometers from the
surface of the earth, and I flatter myself that I can breathe freely in
these strata high above sea level. I even have no doubt that this
acclimatization can be sufficiently developed to exercise a considerable
influence on the scientific use of balloons. At eight or ten kilometers I
have tested upon M. Coxwell and myself the limits of our ability
to live in rarefied air. Frequent trials would increase this height, and
I am certain that it could be extended even more if one used artificial
means to aid respiration. Certainly human lungs would find up there
their Columns of Hercules, but I do not hesitate to declare that these
impassable boundaries are still very far from the regions I have
reached. (Voyages aeriens, P. 9.)
The learned meteorologist of Greenwich, in another passage of
his work, again refers to the future he predicts for ascents to
great heights; he expresses with unusual vigor his unlimited
confidence in the fruitful efforts of science. We shall show in the
rest of this work that these hopes have not been disappointed:
As I have already explained in the introduction, I do not doubt
that some one will succeed in making observations in regions which
I could not attain without fainting. I am persuaded that a day will
come when aeronauts will surpass me just as I exceeded the height of
Barral and Bixio, who in their turn reached altitudes higher than
Sakaroff and Gay-Lussac. I certainly shall not take it upon myself to
set the limits of human activity and indicate the point, if it exists,
where nature says to the aeronauts: "You shall go no further." (Voy-
ages aeriens, p. 67.)
For about ten years, there has been no ascent to a great height,
and in the scientific ascents to moderate heights, the aeronauts,
preoccupied with important problems of meteorology and physics,
neglected completely the physiological phenomena whose slight
modifications could not be observed without having great attention
devoted to them.
192 Historical
We must turn to the ascents organized by the Society of Aerial
Navigation to find facts that interest us. The first among them,
although it did not pass above 4600 meters, gave Dr. Petard, one
of the travellers, very interesting physiological observations. He
begins by listing briefly the temperaments of his travelling com-
panions:
M. Croce-Spinelli is blond, of a lymphatic temperament, nervous,
he is ordinarily inclined to attacks of bronchitis.
M. Penaud is chestnut-haired, of a lymphatic temperament, and
he is disposed towards rheumatism.
M. Jobert is very dark, of an athletic constitution with bilioso-
sanguine disposition.
M. Sivel is dark, of a sanguine disposition; he is very strong, and,
furthermore, not sensitive to aeronautic influences because of the great
number of ascents he has made.
Finally, I am dark and of a sanguine disposition. (P. 118.)
The balloon rose to a height of 4600 meters (429 mm.) , where
the aeronauts found a temperature of — 7 degrees after having
passed through a layer at — 20 degrees:
I could (says M. Petard) observe that the earth below appeared
like a basin, and this illusion makes the hills seem very low and the
ravines very shallow.
The second phenomenon to be observed is the oppression displayed
by M. Croce-Spinelli, at about 3500 meters. I remind you that M.
Croce-Spinelli is predisposed to bronchitis. M. Penaud also expe-
rienced oppression, but to a much less degree than M. Croce-Spinelli.
The other passengers felt none.
We next observed the buzzing in the ears which M. Penaud men-
tioned first at a height of about 2700 meters.
We were all affected at about the same time and in the same
way, but with very marked differences in the intensity of the impres-
sion. For M. Croce-Spinelli it passed to a state of keen pain, and so
persistent that in the train, during our return, he still complained of
pains in his ears.
M. Croce-Spinelli said that in him the buzzing and later the acute-
ness of the pain appeared only during the rapid descents, that is,
when the outer pressure exceeded that of the ear. In me, this buzzing
was perceptible whenever we had a rapid descent or ascent of some
extent, that is, whenever the equilibrium between the inner and the
outer pressure in the ear was broken .... Not only did the sounds
seem weakened, but they also appeared to come from far away.
(P. 119.)
The following observations were made above 4000 meters:
By aid of the buccal thermometer of M. Sainte-Claire Deville and
that of Celsius, I observed a slight drop in the animal temperature,
which varied in the experiments made from 35.02° to 35.07°. The
Balloon Ascensions 193
acceleration of the respiratory rhythm and of the arterial circulation,
very noticeable in all, was in very different proportions in the different
subjects. M. Jobert, whose respiratory rate is normally only 10, had a
rise to 20; his pulse, normal at 100, reached a maximum of only 130.
That of M. Penaud rose from 68 to 104, the respiratory rate from 25
to 45. M. Croce-Spinelli: normal pulse, 72; maximum pulse, 116, at
an altitude of 3500 meters. At 500 meters it was only 86. The number
of inspirations went from 40 to 64. M. Sivel: normal pulse, 80; maxi-
mum, 108; respiration went from 25 to 40. Dr. Petard: normal pulse,
87; maximum, 110; normal respiration, 26; maximum, 35.
These data show that the increase in inspirations reached an
average of 8/5 of the normal value, but that the increase in pulse rate
varied according to the temperaments. While this increase was from
7 to 11 for lymphatic temperaments, it was from 10 to 13 for sanguine
temperaments.
I could not observe, by the pneumo-dynamometer, any appre-
ciable difference in the expansion of the lungs.
The pulse was generally full and regular; but it was not possible
to make graphs of it, since we were not able to use sphygmographs
on account of the drop in temperature, which made exposure of the
skin painful. (P. 120.) ....
We felt a sensation of peculiar well-being impossible to -describe,
although it was expressed by words and mien.
The two celebrated ascents to great height (7300 meters and
8600 meters) carried out by my regretted colleagues Croce-Spinelli
and Sivel, having been undertaken after the first publication of
the results of my researches, their account will naturally be
placed in the third part of this book.
In conclusion, I shall merely quote an account of an English
aeronaut, Simons, who on July 9, 1874, started from Cremorne
Garden, in London, taking Groof, the Flying Man, with his compli-
cated apparatus suspended under the basket.
The balloon contained 27,000 cubic feet; at 1000 feet, Groof
disengaged himself, and falling head first, was dashed upon the
ground. Groof and his machine weighed 130 kilograms:
I looked over the edge of the basket (says Simons), but I was
rising so rapidly that I lost consciousness until I was over Victoria
Park."
But I hasten to add that we should not have too great confi-
dence in the ascents of Simons, who certainly deviated from the
truth in his replies during the inquest on this painful event.
1 Manuscript preserved in the Library of the Institute, under the title of Second Memoire
de M. Charles sur V Aerostatique, 1784. See also L' Art de voyager dans les airs ou les ballons.
specifying the means of making aerostatic spheres, following the method of MM. de Montgolher
and the procedures of MM. Charles and Robert. Paris, 1784, without an authors name (by
Piroux, according to the Uictionnaire des Anonymes de Barbier).
-De Aerostation usu medicinae applicando. Theses de Montpelher, LS4.
194 Historical
3 Mme. B***, born de V***, The Olympic Circus, etc. followed by the Aeronautic Horse
of M. Testu-Brissy, Paris. 1817. oat,, ,
I Relation du seizieme voyage acrien de M. Blanchard, dedicated to S.A.S. Mgr. le prince
de Ligne; br. in-4 of 17 p. Client, 1786.
B Journal de Paris, December 5, 1785.
7 lanuary 5, 1786, p. 18.
*: Ibid., December 20. 1785; p. lir.fi.
8 16th and 20th Messidor and 10th Thermidor, in the year VII. _ .
9 Robertson, Relation adressee aji president de V Acad. imp. de Saint-Petersb., in his
Memoircs recreatifs, scicntiftques ct anecdotiqucs, 2 vols. Paris, 1810.
10 It is, therefore, by an error that all authors, without exception, have attributed a
height of 7470 meters to the ascent of Robertson.
II By Izarn (See the Moniteur universel, January 25, 1804).
12 January 20, 1804; year XII, vol. I. o. 73.
™'4bentcuer des Grafe Z . . . bei einer nachtlichen Luftfahrt. Gilberts Annalen der
Phvsik, vol. XVI, p. 205-209; 1804. .„-,*■ r v ,„
" 14 Souvenirs d'un voyage en Livonic. a Rome ct a Naples, faisant suite aux Souvenirs de
Pans. Translated from the German. Paris. 4 vol.. 1806. .
»•• .■'j.vimoiz </<? Robertson ct Sacharoff, T"'ie 30, 1804. Annates de Chxmie, vol. LI I, p. 121
(Report of Robertson). Philosophical Magazine, 1805; vol. XXI, p. 193 (Report of Sacharort).
1U Account of an aerostatic journey made bv MM. Gay-Lussac and Biot; read to the class
of mathematical and physical sciences of the Institut National, the 9th of Fructidor. in the
year XII Moniteur Universel, of the 12th of Fructidor in the year XII (August 30. 1804.)
17 Account of a balloon journey made by M. Gay-Lussac the 29th of Fructidor, in the year
XII. Ann. de Chimie. vol. LII. p. 75-94, year XIII.
18 September 9, 1S08. , . „ _. ,. „ ,
19 Travels in the Air, by Glaisher, Flammarion. W. de Fonvielle and G. Tissandier. 2nd
edition. London, 1871.
-" Piblioth. britann., vol. LVII, p. 286-300; 1814.
31 May 8, 1812.
-'Mav 16, 1812.
nSilliman's American Journal, vol. XII, p. 161-108; 1827. .
-♦The work of Roch (Essai stir les Voyages aeriens d'Eug. Robertson; Paris, 1831), says
3533 fathoms (6886 meters). „ , ... • • r. •
26 Relation du premier voyage aerostatique execute dans la Reepubliquc mexicaine. I aris.
1835.
-'" I.es Voyages aeriens. Paris, 1870, p. 27. .
-'• Einigcs iiber die Luftreize des H. Green in London am Kronuugstage des Komgs.
Froriep's Notizen, vol. I, p. 71; 1822. See also: Ibid, vol. V, p. 202.)
^ Bericht iiber cine I.uftschiffarht. Ibid, vol. XXXII, p. 49; 1831.
-9 Neue Froriep's Notizen, vol. I, p. 8; 1837.
3,1 Fetter to the "Standard, July, 1837.
31 Handbuch der rationnellen Pathologic. Vol. II, 2nd. part; 1851.
3:5 Vol. XIV. p. 921; 1842. ^ , , , ,
33 Tournal d'un voyage aeronautique fait le 27 juillet 1850. Cpt. R. .lead, des sc, vol.
XXXI," p. 126; 1850. . ,
34 An account of Meteorological Observations in four Balloon Ascents, made under the
direction of the Few Observatory Committee of the British Association for the advancement
of science, by Tohn Welch. Philosophical Transactions, Vol. CXLIII, p. 311-347; 1S53.
35 Glaisher, Flammerion, de Fonvielle, G. Tissandier, Voyages aeriens, Paris, 1870.
::,: 'Travels in the Air, 2nd ed. London, 1871. . ,
37 Mr. Coxwell was an aeronaut by profession; the ascent of June 30 was Mr. Glaisher s
first. . . ,
3S The possibility of opening a balloon valve thus, even for a man in full possession ot
his powers, has been absolutely denied by a professional aeronaut, M. Dute-Poitevin (/ Aeronaute
of April lsTfi, p. 105). I should call attention to the fact that M. Glaisher never considered
M. Coxwell a scientific collaborator. . .
39 In the diagram which accompanies this account, a diagram the original of which, drawn
by M. Glaisher himself, I have had in my possession, the last certain observation of height
is" about 8100 meters; the temperature was —20.6°. #
40 The passage between brackets does not exist in the English text. Can it have been added
by a fanciful translator? Traduttore, traditove. .
A1 This is the number in the English edition and diagram. Voyages aeriens gives 7800
meters.
45 The journal, the Aeronaut, number of August, 1S74.
Chapter III
THEORETICAL EXPLANATIONS AND
EXPERIMENTS
In the present chapter, we shall review the manifold explana-
tions given by different authors, travellers, physicians, and physi-
ologists of the symptoms the varied descriptions of which we have
given in the preceding chapters. We shall add the reports of the
few experiments made in laboratories to throw light on these
obscure problems. This will be only an exposition of theories;
criticisms will come in the following chapter.
We shall follow here a strictly chronological order, since the
proposed explanations would naturally show the effects of current
physiological theories.
The first traveller to describe mountain sickness is, as we have
seen, the Jesuit Acosta; ' he gave an explanation of it which we
quote in full, and which is admirable for its shrewdness, the sound-
ness of its views, and its clearness of expression. On the one
hand, he specifies the real cause, and on the other, he rejects in
advance a mistaken hypothesis:
There is no doubt (he says) that the cause of this distress and
strange affliction is the wind, or the air current there, because the
chief and best remedy to be found is to close the nose, the ears and
the mouth as tightly as possible, and to cover oneself with garments,
especially the stomach, since the air is so thin and penetrating that
it pierces the very vitals ....
By this I am convinced that the element of the air is in this place
so thin and so delicate that it is not proportioned to human breathing,
which requires it denser and more temperate ....
On passes of the Nevada mountains and others of Europe which I
have seen, no matter how cold the air there may be, nevertheless this
cold does not take away the appetite to eat; on the contrary, it
awakens it and does not cause vomiting in the stomach. In the
Indies .... it happens at the same place even when the sun is warm,
195
1 96 Historical
which makes me think that the distress one feels from it comes from
the quality of the air one breathes there. (P. 87.)
When one thinks that these lines were written at the end of
the sixteenth century, three hundred years before Lavoisier and
Priestley, by a man whose specialty was not the study of the
chemical and natural sciences, one is filled with admiration for
the great astuteness of the learned Jesuit and the unusual accuracy
of the expressions he uses. Let us remember also that the pneu-
matic machine had not been invented, and that Torricelli had not
yet been born, when Acosta said that "the element of the air is
in this place so thin and so delicate that it is not proportioned
to human breathing".
It is interesting to compare the explanations of Acosta with
what the celebrated Francis Bacon - wrote thirty years later on the
same subject, in his Novum organum (appeared in 1620). If I am
not mistaken, the comparison is not to the advantage of the
learned chancellor of Verulam:
The rays of the sun produce no heat in what is called the middle
region of the air; which is explained well enough in the schools by
saying that this region is not near enough to the sun from which the
rays emanate, nor to the earth which reflects them. To support this
explanation, we may cite the summits of mountains (unless their ele-
vation is not great) where perpetual snows lie. In fact, certain
travellers have noticed that there is no snow on the summit of the
Peak of Teneriffe, nor on the Andes of Peru, whereas the sides of
these mountains are covered with it up to a certain height. It is
stated, moreover, that at these extreme heights the air is not cold, but
merely rare and sharp; that is why on the Andes it attacks and injures
the eyes and the stomach, which cannot keep food down. The ancients
had already noted that on the summit of Olympus the air was so rare
that to climb to it one must take with him sponges wet with vinegar
and water, and often place them on the nostrils and the mouth, since
the air, because of its rarity, did not suffice for respiration. It is
added that on this same summit, where neither rain nor snow- fell,
and where the wind never blew, there reigned such a calm that when
sacrificers had traced with their fingers characters on the altar of
Jupiter with ashes of the victims, these impressions remained quite
intact until the following year. Even today the travellers who ascend
to the summit of the Peak of Teneriffe make their ascent by night
and not by day; immediately after sunrise, their guides urge them to
descend without delay, apparently because of the danger caused by
breathing an air so rare and asphyxiating.
In fact, it was not until a half century after Acosta, that
Torricelli invented the barometer, and Otto de Guericke the
pneumatic pump. After that, laboratory experiments could go
Theories and Experiments 197
on simultaneously with observations made by travellers. But
strangely enough, for a long time physicists tried exclusively to
study the effect of a vacuum, that is, the total lack of air. They
did not inquire what would happen from a sojourn in air which
was merely rarefied; for them, it seems, only two possibilities
existed: to have air or to have no air. And yet, by a strange
contradiction, many of them, trying to find out why animals which
are kept in closed vessels die, were convinced that it was because
of "the decrease in the elasticity of the air". Very strange! They
did not investigate experimentally to see what would happen to
animals which were subjected to such a decrease from the very
outset; after the famous experiments of Pascal on the Puy-de-
Dome (September 22, 1648), they were not surprised to see ani-
mals continuing to live, which, on the mountains, were subjected
to a decrease in the elasticity of the air enormously greater than
that which accompanies asphyxia in closed vessels.
At any rate, the members of the famous Academy del Cimento 3
tell us that:
As soon as Torricelli first advised the experiment with mercury,
he began to think also how he would imprison different animals in
a vacuum, so as to observe in them movement, flight, respiration, and
all the other phenomena which could be observed. But being without
the instruments necessary for this sort of experiment, he did the best
he could. For the small and delicate animals were overwhelmed by
the. mercury, through which they had to climb upward, when next
the vessel was overturned and they were plunged into the other
mercury. And they were then quite or almost dead, so" that one
could not tell whether they were injured more by the mercury which
suffocated them or by the lack of air. (P. 46.)
As for them, they tell in their memoirs for the year 1667 the
numerous experiments they made on animals, using barometric
tubes, the large chamber of which was closed by a bladder.
These animals were leeches, snails, insects of different sorts,
reptiles, and birds. The experiments give with remarkable exact-
ness the different symptoms displayed by these animals which
were subjected instantaneously to an almost perfect vacuum. The
physicists of Florence noticed besides that, in fish placed in the
vacuum, the "air bladder" deflated and the fish then remained at
the bottom of the water; in consequence, they performed curious
experiments, thanks to which they discovered the "little vent-hole"
through which the air escapes when it is expanded by the effect
of the diminution of pressure.
We do not find in this account any very definite theoretical
198 Historical
explanation of the effect of the vacuum. It appears, however, that
for the academicians of the Cimento, a vacuum acts simply by the
removal of air. Furthermore, their translator and commentator
van Musschenbroeck explains it very clearly when he says:
If we wish to know exactly how long a little bird can do without
air, let him be plunged under water; for then he cannot breathe air,
and he is immediately in a situation similar to a vacuum.
These notes of van Musschenbroeck 4 also contain a very curious
description of the phenomena presented by an animal subjected
to the action of a vacuum, with an interpretation of the causes of
death, an extremely interesting interpretation, although it savors
of the false ideas of the epoch about the pulmonary circulation:
We shut a rabbit in a glass receiver, and by means of the pneu-
matic pump drew out all the air; the animal at first was uneasy,
sought air, swelled up all over; its eyes protruded, it defecated,
sought a way out all around the vessel, sat up hardly breathing,
grew weak and fell in convulsions, lay down on its side, and finally
died; all these things happened in half a minute, after the pump began
to work and rapidly removed all the air from the vessel: the whole
body of the animal lost its air and was deflated; then when we opened
the chest, we found the lungs small, collapsed, solid, heavier than
water. The whole body of the animal swells in the vacuum because
the ventricle and the intestines contain much air, which, when it is
no longer compressed by the outer weight of the atmosphere, expands
in all directions as a result of its elasticity and distends the abdomen.
But the blood and the other humors have elastic air mingled with
their parts, which then, not being compressed, expands, recovers its
elasticity and distends all the vessels, so that all the body of the
animal must swell in all parts, especially the eyes, the humors of
which contain much of this air; experimentation has taught me this, as
I have tried to prove in my dissertation De aeris existentia in omnibus
animalium humoribus.
Moreover, the animal enclosed in a vacuum cannot inhale air into
its lungs, and although it tries to expand its chest, and often repeats
this expansion, nevertheless nothing enters from the outer part of the
lungs into the air vessels or vesicles. That is why the contractile force
natural to all fibres compresses the vesicles; the lungs collapse, become
denser, and specifically heavier than water; but whereas the vesicles
attached to the extremities of the tracheal artery are compressed, the
circulation of the blood is hampered in the arteries and the veins
which surround the whole vesicular surface in abundance, and in those
which are situated in the interstices left around each vesicle. But in
this adult animal, the blood of the whole body, pumped out by the
right ventricle of the heart, must pass through the vessels of the lungs
into the left auricle and ventricle, so that from there it can be
pumped out into the parts of the body. When the vesicles of the
lungs are contracted and compressed in the vacuum, the blood vessels
Theories and Experiments 199
are also compressed, nothing passes from the right ventricle of the
heart 'into the left, the blood is not pumped to the brain, the cere-
bellum, or the other parts of the body, and the circulation of the
blood, upon which life depended, is ended. But before the circulation
of the blood ceases entirely in the lungs, the air which is mixed with
the blood escapes from the interstices, collects, grows rarefied, is
pumped to the brain, causes obstructions here and there; hence comes
the disorganized secretion of animal spirits in the brain, and hence
their irregular influence upon the muscles of the body, which is the
cause of the convulsions, and delays death. I do not doubt that all
animals whose heart has two ventricles and is not pierced by an oval
hole would die in a vacuum with the symptoms which I have re-
ported . . .
The animals which have an oval hole opened in the heart live a
long time in a vacuum, and die only because of thirst, hunger, etc.
(P. 55.)
And so, in the opinion of the celebrated professor of Leyden,
the death of animals subjected to a vacuum occurred as a result of
a stoppage of the circulation of the blood, a stoppage due to the
collapse of the lungs from which the vacuum had removed all the
air; furthermore, the gases which escaped from the blood ob-
structed the vessels, especially in the brain:
They say (adds Musschenbroeck) that birds endure rarefied air
more easily and with less inconvenience than land animals, because
they are used to breathing a rarer air when they fly high: however,
they cannot endure an air three-quarters rarefied; that is why they
can rise only to a certain height in the atmosphere and not to all
kinds of heights: these animals are uneasy in a rarer air, because this
air can hardly, by its elasticity, expand the vesicles of the lungs unless
the chest is expanded by very great force; and this is the cause of the
uneasiness felt by the men who have climbed to the summits of the
high mountains of Armenia, Savoy, the Pyrenees, and Teneriffe, where
the air is much rarer than that which is near the surface of the earth.
(P. 57.)
In France, the Academy of Sciences thought at first of making
experiments with "the machine of M. Guericke of Magdebourg";
but the only one which its Memoirs 5 have reported to us dealt
with a gudgeon which, after the action of the vacuum, fell to the
bottom of the water, "its bladder being emptied".
However, in England, one of the most remarkable experiment-
ing physicists of the seventeenth century, Robert Boyle,6 had
undertaken very interesting researches on the life of animals sub-
jected to a vacuum. He used the pneumatic pump. His experi-
ments, published in 1670 in the Philosophical Transactions, surely
antedate this epoch considerably since some of them are quoted in
200 Historical
the memoir mentioned above of the Physicists of Florence, printed
in 1667.
This noteworthy work is divided into several parts:
In the First, Boyle questions whether aquatic birds, which can
remain for some time under water "because of the peculiar struc-
ture of certain vessels which they have around the heart", could
sustain better than other animals the lack of air in a pneumatic
machine. And, after an experiment made on a duck, he replies in
the negative.
In the Second and the Third, Boyle reports the results of ex-
periments made on snakes and frogs, which sustained the vacuum
for a long time.
In the Fourth, he says that he experimented on new-born kit-
tens, and that he was astonished to see that these animals held
out three times longer than older animals of the same size could
have done.
Part V. Experiment to find out the volume of air contained in
the pores of water.
Parts VI and VII. On the effect of the vacuum upon oysters,
crabs, and a gudgeon.
Part VIII. Experiment on a bird and a frog enclosed in the pneu-
matic machine, both having the abdomen opened.
Part IX. Experiment on the heart of an eel.
Part X. Comparison of the time it takes to kill animals in water
and in the pneumatic machine.
In Part XI, Boyle reports the sufferings of which Acosta com-
plained in his trip over Pariacaca, and he declares that he had
heard similar reports from travellers who made the ascent of
Mount Ararat, the Peak of Midi, the Peak of Teneriffe, and even
the Cevennes. In Chapter I we quoted these different observa-
tions. He asks himself in this regard
Whether the difficulty of breathing which certain persons expe-
rienced on the heights of Pariacaca, and perhaps on some other very
lofty mountains, comes solely from the lack of elasticity in the air in
these high places; whether we should not attribute it, at least in part,
to certain penetrating vapors with which the air may be laden in
places. (P. 42.)
Part XII. Effects produced upon an animal by the alternate rare-
faction and condensation of the same air.
Part XIII contains the account of a very remarkable experi-
ment, which Magnus was to repeat, more than a century and a
half afterwards:
Theories and Experiments 201
The blood of a lamb or a sheep was brought me still warm from
the slaughterhouse, where care had been taken to break the fibers to
prevent coagulation. This blood I placed in a glass vessel with a wide
opening, and put the vessel in a receiver; the air was immediately
pumped out very carefully; but the effect of this operation was not
so prompt or so apparent, especially at the beginning, as I should have
expected it to be in so spirituous a liquid; however, after a long delay,
we saw that the most subtle parts of the blood appeared through the
more viscous parts, and formed bubbles, some of which were as large
as big beans or nutmegs; sometimes the expansion was so strong, that
the blood boiled up out of the glass vessel, of which, however, it
hardly occupied a quarter at the beginning of the experiment. (P. 46.)
Robert Boyle drew air in the same way from other organic
liquids and all the soft parts. And he explains with keen sagacity
the purpose of these experiments; he wished to find out
What, joined to the failure of respiration, could contribute to the
death of animals in the vacuum of the pneumatic machine; as a
matter of fact, it appears that the bubbles which, when the ambient
air is removed, form in the blood, the other liquids, and the soft parts
of the body, can by their number and their expansion in some places
swell and in others contract the vessels which carry blood and nour-
ishment into the whole body, especially the smallest of these vessels,
can choke passages or change their shape, and finally stop or disturb
circulation in a thousand ways. Add to that the irritation caused in
the nerves and the membraneous parts by forcible distentions; an
irritation which produces convulsions and causes death more quickly
than simple lack of air would have done. This formation of bubbles
takes place even in the smallest parts of the body, for I have seen a
very apparent bubble moving from side to side in the aqueous humor
of the eye of a viper at the time when this animal seemed violently
distressed in the receiver from which the air had been exhausted.
(P. 47.)
In Part XIV there is reported a very fine experiment, by which
Boyle shows that animals become accustomed to the effect of the
rarefaction of the air, and suffer less from it in successive experi-
ments.
Part XV. Experiment which shows that air can preserve its
elasticity while ceasing to be suitable for respiration.
Part XVI. On the use of air for causing the escape of exhalations
from the body.
Part XVII. Ability of the slug and the leech to endure lack of
air.
Part XVIII. Trial of the vacuum upon certain crawling insects.
Part XIX. Winged insects enclosed in a vacuum.
Part XX. On the need of air for motion shown by ants and mites.
In another work,7 the celebrated physicist again dwells upon the
experiment relating to the bubbles of air which escape from
202 Historical
organic liquids placed in a vacuum, and he is led to ascribe to
the escape of these bubbles an important part in the symptoms
due to decreased pressures:
When I re.call how our machine (the pneumatic machine) brings
out air invisibly held in the pores not only of the water, but also of
the blood, serum, bile, urine, and other liquids of the human body;
when I reflect that (as I have shown experimentally elsewhere) the
pressure of the atmosphere and the elasticity of the air act upon
liquids and upon bodies immersed in these liquids, and upon bodies
directly exposed to the air, I am inclined to believe that simple
changes of the atmosphere from the point of view of weight can, in
some cases, have a perceptible influence even on the state of health
or sickness of man. When the ambient air, for example, suddenly
becomes lighter than before or than usual, the spiritual or airy par-
ticles, which are contained in abundance in the blood, naturally will
swell this liquid, being able thus to distend the large vessels, and
change considerably the speed of the circulation of the blood in the
capillary arteries and the veins. That through this alteration several
changes can occur in the body will not seem improbable to those who
know, in general, how important the rhythm of the circulation of the
blood is, although, as to its special effects, I leave them to the specu-
lation of the physicians.
These experiments were repeated, and varied in different ways
by all the physicists of this time: Stairs, Derham, Huyghens,
Papin, du Hamel, etc.
I shall quote an extract of the work written in collaboration
by Huyghens and Papin; this passage is remarkable for the wholly
mechanical explanation given in it of the cause of the death of
animals placed in a vacuum in the pneumatic machine.
According to Huyghens and Papin,8 warm-blooded animals
never revive when they have been placed in a perfect vacuum.
They then add:
M. Guide, who has often dissected these animals which we killed
by a vacuum, has observed among other facts that their lungs sink
in water, and he maintains that the solidity or density of the lungs
of animals which have died thus in a vacuum results from the fact
that the blood, carried into the lungs by the arterial vein, presses
with such violence upon the bronchi of the tracheal artery, that it
forces the air out of them and brings together the walls of these col-
lapsed conduits, as if they had been glued together; but, for my part, I
do not believe that the blood of the arterial vein can compress the
bronchi in this way, because the blood has its own vessels which con-
tain it and prevent it from compressing others. . . .
It is therefore more probable that if the lungs are compressed,
it is done by the pleura which can be distended within the chest as
the skin is distended on the exterior; but the lungs need not be
Theories and Experiments 203
compressed in a vacuum to sink in water; for I have several times
placed in a vacuum pieces of lungs and whole lungs, and they
remained extremely inflated while in the vacuum; but as soon as air
was admitted to the receiver, they became flat and red and sank
when placed in water. (P. 150.)
Finally, before leaving this fruitful epoch, I think I should
reproduce here a very curious plan of experiments suggested to
the English physicist Beale ;| by his celebrated compatriot Boyle:
It would be, I think, very important to see the effects produced
on plants placed in Mr. Boyle's air-pump, and likewise on cherry-
blossoms, etc.
The distinguished Mr. Boyle suggests that in the approaching
season I should see:
1. Whether seeds germinate in the vacuum receiver;
2. Whether lack of air is harmful to sensitive plants;
3. Whether grafting pear buds on spina cervina (the only vege-
table purgative known in England) will give the pears purgative
qualities.
4. Whether the eggs of silkworms will hatch in the receiver when
the season has arrived.
I should, besides, investigate whether aquatic plants live in water
from which the air has been removed by the pump ....
One of these experiments was carried out on lettuce seeds. Those
which had been planted in open air measured IV2 inches in height
after a week, the others had not sprouted; but they germinated when
air was admitted.
We shall not dwell longer on these attempts which, as we have
noted, relate almost exclusively to the effect of an almost complete
vacuum. Except for a few experiments of Boyle and Musschen-
broek, air that is merely rarified is, in fact, not considered in them
at all.
And yet, as we have seen, these physicists tried to find in these
experiments explanations for the physiological disturbances ex-
perienced by travellers who ascend high mountains. This interest
is shown also in a curious passage in the History 10 of the Academy
of Sciences for 1705; it shows at the same time how many uncer-
tainties then assailed the minds of the physicists themselves on the
question of measuring altitudes by the barometer:
There is some reason to believe that the air expanded in a tube
is not quite of the same nature as air at the top of a mountain. If
one puts lukewarm water in the vacuum machine, it boils very hard
as soon as half of the air has been pumped out, because that which
was naturally mixed with this water, and which had already been
warmed a little, when it is freed of half the weight which pressed
204 Historical
on it, tends to escape entirely. Hence M. Mariotte has conjectured
that if one was at an elevation where the weight of the atmosphere
was diminished by half, the blood, much warmer than lukewarm
water and still full of air, would boil, so that it could no longer circu-
late, and we must admit that the conjecture was well founded. How-
ever, MM. Cassini and Maraldi, who have ascended to altitudes where,
according to their calculation, the weight of the atmosphere was
almost a half less, felt no distress caused by the rarefaction of the air.
Many persons who have been still higher felt no more than they.
I do not need to go to great lengths to show the mistake of
the writer in regard to the height of the mountains which Cas-
sini and Maraldi ascended. A few lines above, he said himself
that "the barometer hardly drops 5 or 6 inches on the highest
mountains where observations have been made".
Later, the Italian physicists once more took up the study of
these important problems. Veratti, an academician of Bologna,
made numerous experiments11 on this subject. He begins by re-
calling that two very different explanations have been given for
the death of animals in the vacuum:
According to the clever Borelli, this death occurs because, when
the outer air is removed, the air contained in the blood and the humors
is greatly rarefied and distends the vessels beyond the endurance of
the animal. According to this idea we must conclude that in the blood
and the other liquids a sort of effervescence is caused which rarefies
them and slows their movement, that the nerves are compressed by
it and the course of the animal spirits checked, which necessarily
brings on the death of the animal ....
M. Musschenbroeck . . . thinks that the cause of this phenomenon
lies in the lungs. He thinks that the pulmonary vesicles, when they
receive no more outer air, contract more than is natural .... which
causes the vessels to be cramped and the blood to be stopped in them
.... (See above the opinion of Musschenbroeck and that of Guideus.)
Veratti, having placed quails in the vacuum, found that their
lungs floated after death. The lungs of rats and rabbits floated
also, but those of kittens a week old did not. He concludes from
this:
That Musschenbroeck and Guideus had either used in their experi-
ment new-born animals, in which the oval hole was not yet closed,
and whose lungs could not expand sufficiently to become specifically
lighter than water; .... or that they left the animals in the vacuum
for too long a time after their death; .... or that the air in the
receiver was perhaps more rarefied in the experiments of these physi-
cists .... who were not careful about specifying the degree of
rarefaction which they used .... As for him, he merely rarefied the
air to the point necessary to kill the animals ....
The lungs, he says in conclusion, are heavier than water only in
Theories and Experiments 205
case they have been kept in the vacuum for some time after the death
of the animal. That proves that this death should not be attributed
to the contraction of the lungs .... Perhaps the lungs do not become
denser in the vacuum, and seem so when they are withdrawn only
on account of the pressure of the outer air, which then begins to
act upon them. Besides, when all the other parts of the body swell in
the vacuum, it is not clear why the lungs should be the only excep-
tion.
We see that Veratti is far from being satisfied with the result
of the experiments of the Dutch physicists. However, he does not
take sides definitely, although he is inclined towards the opinion
of Borelli.
In another memoir 12 which he devotes to the study of asphyxia
in closed vessels, he makes an observation, mistaken to be sure,
which shows how complex these questions seemed to him:
None of the animals which die in the receivers (confined air)
have convulsions, as always happen to those which die under the
receiver of the pneumatic machine; which proves that the cause which
kills animals in confined air is very different from that which kills
them in a vacuum.
We are really much surprised to see, after that, that in the
explanation of the death of the enclosed animals he gives an im-
portant role to "the destruction of the elasticity of the air, proved
by his experiments", that is, to a decrease in pressure of a few
millimeters of mercury.
Another Italian, J. Fr. Cigna,13 shortly after, carried on research
of the same type on death in closed vessels. But he was the first
to have the idea of studying what would happen to animals kept
until death in closed receivers, in air of different degrees of rare-
faction.
He used a bottle containing "about 50 pounds of water". In it
he placed a sparrow, then pumped out the air in two minutes to
a decompression of 16 inches, 10 lines:
The animal vomited at the beginning, went through a few con-
vulsions, then seemed in fairly good condition for a few instants. Its
respiration at first was shallow and rapid; it became still more so
afterwards; soon it was rapid and deep, and finally deep and slow;
then came convulsions which ended its life. The mercury had risen
little by little in the siphon, so that at the time of the animal's death its
height had increased about 4V2 lines. Counting from the moment when
communication of the tube with the pump had been cut off, the
sparrow had lived 35 minutes ....
After washing the bottle, I placed another sparrow in it; I pumped
out the air so that the mercury rose in the siphon only to 13 inches,
5 lines, and I cut off the communication of the bottles with the pump.
206 Historical
As on the first time, all these operations were carried out within two
minutes after the sparrow had been inserted. This animal showed the
same symptoms as the first. It lived 70 minutes; at its death, the
mercury had risen 7 lines above the point at which it stood at the
beginning.
Finally I placed a third sparrow in the bottle, without having
rarified the air (the height of the mercury was then 27 inches, 6 lines).
The symptoms were the same with the exception of the convulsions.
The animal lived three hours and a half. At the time of its death,
the mercury had risen in the siphon about 1 inch and IV2 lines.
In these experiments, the quantities of enclosed air were to each
other as the numbers 128, 169, 330, and consequently almost as 3, 4, 8.
The duration of life of the sparrows was as the numbers 35, 70, 210,
and almost as 1, 2, 6; whence it follows first that in airs of different
density, it does not correspond to the quantity of air, but increases in
greater proportion than the quantity of air when its density is greater,
and consequently, that the same quantity of air supports the life of
the animals longer when it is condensed than when it is rarefied.
(P. 165.)
From these experiments Cigna draws the following conclusion:
A rarefied air is not harmful to the life of animals from its rarity,
but because it is altered sooner than when it is denser; for in such an
air, the animals breathe at first without difficulty; their respiration
becomes labored only by degrees, and in proportion to the' capacity
of the receiver; in a word, everything goes on just as in an air with
its natural density. If the air were harmful on account of its rarity, it
would be equally harmful no matter what the capacity of the receiver
might be. (P. 166.)
And to prove it, he performs a double experiment, in which two
sparrows were subjected to the same very low pressure (from 91/?
to 714 inches), one in a closed bottle, the other in a receiver in
which he renewed the air frequently. The first died, whereas the
second was "full of health" after more than a half-hour:
I conclude from this experiment (he says) that an air, extremely
rarefied under the pneumatic receiver, is capable of maintaining respi-
ration and life, provided it is renewed, and that is why animals
endure the condensation of enclosed air much better than an equal
rarefaction; that is also why a flame burns and animals live on the
highest mountains, although the air there is extremely rarefied,
whereas they soon die under a receiver in which the air has been
rarefied to the same degree. (P. 167.)
But I call particular attention to the remarkable explanation
which Cigna gives for the harmlessness (which he certainly exag-
gerates greatly) of air which is rarefied and renewed:
It is obvious that the air needs only to be dense enough to expand
the lungs by its pressure; now to expand the lungs, this pressure
Theories and Experiments 207
needs only to be able to overcome the resistance which the contractile
power of these organs opposes to it, for there is no thoracic air to
increase this resistance, and this pressure hardly exceeds that of two
inches of mercury; whence it follows that an air, even when extremely
rarefied, still exerts sufficient pressure for the mechanism of
respiration.
So he reaches this opinion that "the suffocation of animals kept
in closed vessels is the work of vapors". But following him in this
path would lead us astray from our subject.
We shall return to travellers who have ascended lofty moun-
tains; but we should first report the interesting experiments of
the poet-naturalist Darwin 14 and the curious theoretical conclu-
sions which he draws from them; we shall return to these explana-
tions later.
The author asks himself whether there really exist in the blood
elastic vapors of some sort or other, which could cause "lunar and
equinoctial maladies" to be attributed to variations of the atmos-
pheric pressure:
The truth of this opinion (he says) seems to be demonstrated by
the following experiment: Four ounces of blood are drawn from the
vein of the arm and immediately placed in the reservoir of an airpump:
when the air is removed, the blood begins to froth and rise in bubbles
so as to occupy ten times its original volume.
But that reasoning is mistaken, says Darwin. If, in an animal
which has just been killed, a certain length of a vessel full of blood
is isolated between two ligatures, and this fragment is placed in a
vessel full of water, under the receiver of the pump, it remains at
the bottom of the water when a vacuum has been made, without
rising or swelling, as it should do if it really contained air:
So a great change is produced in the blood drawn from the vein
by the introduction of atmospheric air .... Therefore a cupping-glass
applied to a living animal brings out no froth, as happens in a
vacuum.
It is, therefore, probable that animals can undergo great variations
in pressure without inconvenience .... Some persons who have
ascended lofty mountains report that they have spat blood; but that
has never been noted in animals placed in the pneumatic machine,
where the decrease in pressure was greater than occurs on the highest
mountains. This blood-spitting was therefore an incidental disturb-
ance, or was the result of the violent exercise of the ascent.
We have seen, quoted above by Veratti, the explanation at first
given by Borelli of the symptoms of decompression, which he him-
self had experienced when he ascended Etna; he thought they were
the result of a sort "of effervescence which might occur in the
208 Historical
blood and the other humors". But Borelli did not continue long
in this opinion, and, absorbed exclusively by his theory of effort,
he narrowed the question greatly: 15
I then perceived that this distress was not produced by the exces-
sive rarity of the air or by any corruption of its qualities, since, when
we were sitting down or were on horseback, naturally breathing the
same air, we felt no more oppression than on the seashore. I have
given a solution of this problem in my Meteorology 16 of the Fires of
Etna; but when I reflect upon it, I cannot remain in this opinion, and
I now come to a more probable explanation of it. (P. 242.)
Borelli then reminds the reader that he has shown why a fa-
tiguing labor necessarily brings on panting. He will now show why
locomotion in rarefied air cannot take place without great fatigue,
whence comes the difficulty in breathing. (It is his proposition
CXXIII.)
A labor can become fatiguing for two reasons: first, if the resist-
ance increases; second, if the strength lessens . . .
The air contained in the chest, as I have said, helps the effort of
the muscles, compressing by its elasticity the air- and blood-vessels.
Therefore, when the air is very much rarefied, although it is com-
pressed by the thorax as the dense air was, it acts less upon the vessels,
and consequently aids the muscles less .... Therefore, in rarefied
air the same work will require greater effort, since the strength is
lessened, whence comes the lassitude, which was to be demonstrated.
(P. 243.)
Bouguer 1T does not display any greater astuteness; the well-
known fact that under certain circumstances the symptoms attack
only those on foot and not horsemen makes him attribute them to
fatigue; for more serious cases, he resorts to the cold:
What proves this irrefutably is that one is never exposed to this
illness when one is on horseback or when he has once reached the
summit, where the air, however, is even rarer. I do not deny that this
great rarity hastens lassitude and contributes toward increasing ex-
haustion, for respiration becomes extremely painful; however little one
exerts himself, he is all out of breath at the slightest movement; but
nothing of the sort takes place as long as one remains inactive. . . .
We passed three weeks (August, 1737) on the summit of Pichincha;
the cold there was so keen that one of us began to feel some scorbutic
symptoms, and the Indians and the other servants whom we had en-
gaged in the country had violent colic: they passed blood, and some
were forced to descend; but when once we were camped on the edge
of the cliff, their illness was always the result of the severity of the
cold to which they were not accustomed, without the rarity of the air
seeming to be the cause of it, at least, not the immediate or near cause:
I investigated this the more carefully because I knew that most of the
Theories and Experiments 209
travellers had been deceived in this, because they did not distinguish
sufficiently between the different effects. (P. 262.)
However, Bouguer gives some importance to the decrease in the
weight of the air:
The slight hemorrhages no doubt resulted from the fact that the
atmosphere, having less weight, was not of enough assistance by its
compression to help the vessels restrain the blood, which, for its part,
was still capable of the same action. (P. 261.)
Ulloa,18 who in other regions of the Cordillera had seen "riders
as sick as those on foot", could not assume, as Bouguer had done,
that fatigue was the principal cause of the symptoms. So he does
not even mention this hypothesis. But he triumphantly discusses
that of the cold.
The idea of the rarity of the air occurred to him, but one cir-
cumstance puzzled him, which puzzled many others, namely, that
these symptoms do not appear in the lofty regions near Quito:
Certainly one cannot attribute this distress to the cold, for if that
was the only cause, this illness would be common in all cold countries.
It must therefore come from the properties of the air, either its light-
ness or some other quality which we do not know. This illness does
not appear in the lofty regions of Quito, the altitude of which is as
great as that of Peru, for it is different from the sickness which we
call paramarse: at least no one has experienced it when the matter
was being considered, so that no one has spoken of it, whereas it is
very common in the lands lying before these regions. We should note
also that those who are likely to vomit at sea are also so inclined on
the Punas, whereas those on whom the sea makes no impression do not
experience this distress on these peaks either. Something of the sort is
felt on the lofty mountains of Europe and other mountain chains; it is
peculiar to delicate persons, but these symptoms are not so noticeable
or so serious or even so general as in the regions of America. That
which is felt in Europe comes only from the rarity of the air and
from the cold on these heights, two circumstances which might well
produce some ill effect. (P. 117.)
Then, in regard to the symptoms noted in beasts of burden,
Ulloa reports, but only to oppose it, the opinion common in his
time and even today almost universally accepted in these regions
of South America, that these symptoms are the result of poisoning
by metallic emanations from the ground. And yet he cannot keep
from believing in some foreign substance permeating the air:
The inhabitants of these regions say that it is because the animals
are then passing over mines, for they claim that the mountains are full
of minerals, from which are emitted through the pores of the earth
210 Historical
molecules of antimony, sulphur, arsenic, and others, to which they
attribute these symptoms.
But the objection may be raised that if this opinion were well
founded, the men who ride on these animals would experience the
same distress when they have stopped, which is not the case. We
must therefore believe that it is due only to the extreme rarity of the
air, which is filled, moreover, with some foreign body disseminated in
it, although this foreign substance does not come from the pores of the
earth. We may also say that it is not probable that there are minerals
enclosed within all these peaks where the symptoms occur, since we
see no outer sign revealing them; if it were so, there would be no
mountain or slope in these chains, covering several hundred leagues,
in which one would not find some mineral. (P. 116.)
Ulloa also says a few words about symptoms which are much
less serious, but which his successors did not always have the
sagacity to distinguish, as he did, from mountain sickness:
The dry, rare air causes such dryness that the epidermis, and
especially the skin covering the lips, chaps and cracks; this causes
pain, and soon blood issues from them; the hands become rough and
scaly: this roughness is particularly noticeable on the joints and upper
part of the fingers, the scales are thicker there than elsewhere, and
they take on a darkish color which is not removed by lotions. These
affections are called chugno, a term which the natives use for anything
that is wrinkled and hardened by the cold. (P. 111.)
All these data were known to the illustrious Haller, who re-
views them briefly in the third volume 19 of his immense work,
and tries to explain them with the data of the physics, chemistry,
and physiology of his time. The mechanical influence of the pres-
sure of the air seems to him absolutely predominant. In his dis-
cussion, he utters this very strange idea, already suggested by
Cigna, that the air of altitudes would act on the organism in a
less painful manner than that which was rarefied to the same de-
gree under the pneumatic bell-jars:
The air (he says) weighs upon the body of man from all sides
. . . and different authors estimate this weight at variable amounts
from 31,144 to 42,340 pounds. Children are more compressed propor-
tionately than adults, since the surface of their bodies diminishes less
than the mass.
All of this varies in the same locality, because the mercury of the
barometer rises or falls about three inches, and thence come differ-
ences which have been estimated at from 3062 to 3982 pounds. The
variation is much greater if we compare the air of the highest moun-
tains to that of the deepest coal mines ... In this case, it may go
from 36,292 to 19,281 pounds (according to La Condamine, it would be
only 17,000 pounds on the top of Chimborazo, which is an inaccessible
peak anyway). And this difference appears even much greater, if in-
Theories and Experiments 211
stead of a man we. consider a fish living in submarine depths as great
as 400 fathoms ... We should then reach a pressure of 2,272,000
pounds.
The English academicians did not doubt that a man can live at
a depth of 200 fathoms. (P. 191.) . ...
The effects of this pressure on the human body cannot fail to be
great; we see that when we place animals under the pneumatic bell.
The body is subjected to the pressure which presses the blood-
vessels, the muscles, and the soft parts against the bones. And since
in the humors of the body, in the air passages, in fact, everywhere,
there is air kept in a small volume by the pressure, when this pres-
sure is removed, the animal swells up all over, from the expansion of
the lungs, the intestines, and the air contained in the vessels and even
in the cell meshes. (P. 192.) . . .
But there is a great difference between air rarefied by vapors or
that rarefied by the removal of a part of itself, and that air which is
lighter because of the altitude and its distance from the center of the
earth. In the latter, in fact, although it has lost half its weight, respi-
ration takes place without difficulty; this I experienced on the moun-
tains Jugo and Furca. (Haller quotes Cassini, Bouguer, etc.)
And one can even live a long time at these heights ... I agree
with Arbuthnot, who teaches that a sudden shift to rarefied air is hard
to endure at first, but that one can become accustomed to it. Perhaps
that is the reason why birds endure rarefied air more easily than other
animals (Derham). It is easy to understand, in fact, that the pressure
upon our humors and our vessels will increase in proportion as the
outer air becomes denser, and vice versa. (P. 193.) . . .
We easily understand the disadvantages of rarefied air; we shall
see that it cannot inflate the lungs completely. Since 'the pressure no
longer sustains the vessels of the body, they resist the heart less and
are more easily ruptured. In a very much rarefied air, the danger is
increased by the expansion of the air contained in our humors. Light
air, which does not fully inflate the lungs, makes the passage of the
blood in these organs more difficult, and allowing less blood to reach
the left heart in a given time, removes from it the stimulus which
urges it to contract. (P. 196.) . . .
In rarefied air, strength is diminished. In our Alps, those who
have lung ailments die when they are in lofty places, especially if it is
warm there, for cold moderates the ill effects of rarefied air. The
sturdy mountaineers of the Alps carry enormous burdens in lofty
places.
The fever, prostration, slight hemorrhages and hemoptysis, an
unfortunate example of which one can find in Scheuchzer,20- which
symptoms certain travellers have experienced while passing through
the mountains, I attribute rather to the fatigue of the ascent and to
the strain on the respiratory powers. In fact, travellers who are rest-
ing or are on horseback have no such symptoms. (P. 197.)
So, according to the celebrated Swiss physiologist, the effect of
the rarefied air has as its principal causes the lessening of weight
pressing upon the surface of the body, the dilation of the superficial
212 Historical
blood-vessels, and the increased difficulty of the passage of the
blood through the lungs. We shall return, in. the next chapter, to
the value of these theories which it would be premature to discuss
at present.
According to the account of Haller, we see that travellers in
the Alps had already experienced painful effects of the decrease
of barometric pressure. However, no explorers had yet trodden
the summits of any of the giants of the Alps, Mont Blanc, Monte
Rosa, nor the Jungfrau, which rise to an elevation of more than
4000 meters. Below this level, even slight symptoms are rather
rare. The Genevan physicist de Luc21 is surprised at that, when
he considers the great decrease in the weight of the air supported
by the body; he draws from it a very reasonable conclusion about
the effect on the health which certain physicians attribute to baro-
metric changes:
We were very comfortable near the little rocks to which we had
descended (the Buet glacier, barometer 19 inches, 6 lines; 9355 feet
above sea level) . . . We were surprised that we perceived the dif-
ference in the density of the air only through our instruments, that no
discomfort or disagreeable sensation warned us that the air we were
breathing was nearly a third less dense than that of the plain, that
the weight of the atmosphere upon our bodies was one hundred quin-
tals less without any disturbance of the inner equilibrium. What a
marvelous machine this is, which adapts itself to such great variations
in the very causes of its principal movements, without their ceasing to
be regular!
I cannot refrain from saying in this regard how much mistaken
certain doctors were who attributed to the difference in the weight
or the density of the air the changes experienced by certain persons
when the barometer falls, and who undertook to explain them by the
lack of equilibrium between the inner and the outer air, or by the
effect which a more or less dense air can produce upon the movements
of the heart and the lungs.
If these variations had a perceptible effect upon our organs, what
would become of those chamois hunters who pass every day from the
depths of the valleys to the summits of mountains equally high . . .
Even asthmatic persons are not affected by them; at least I was on the
mountain of Saleve with one of my friends who feared this effect and
did not experience it. (P. 328.)
We have seen that Canon Bourrit, in his ascent of Buet, was
less fortunate than de Luc; the accounts of de Saussure and Pictet
show, moreover, that this mountain, in spite of its moderate height,
is one of those on which travellers are most easily affected in the
ascent. In this connection, Bourrit -2 makes a strange remark about
the difference in density, at an equal altitude, between the air of
Theories and Experiments 213
the Alps, which makes one ill, and that of the Cordilleras, "where
one feels no effect":
I have noted that these symptoms can be avoided by walking . . .
a means of renewing the air in the lungs and maintaining their activity.
I know that it would be difficult, not to say impossible, to live a
long time on Mont Blanc . . .
From all these circumstances we must conclude that the air which
we breathe on the high Alps is much rarer than that of the Cordilleras
at the same height, because the latter are beneath the equator, and for
that very reason they are more impregnated with heavy and dense
vapors. (Vol. II, p. 98.)
If this idea seems very strange to us today, what shall we say
about that of d'Arcet,- ■"■ who first denies mountain sickness (he had
ascended only the peak of Midi) and then asks himself whether
the air of lofty regions is really rarer than that of the plains!
As to the difficulty in breathing which it has been thought was
sometimes felt on lofty mountains, and which we have never experi-
enced, I think that it may come from the oppression which one feels
when, heated and weary with the ascent, he reaches a very open and
very lofty summit. There, he is suddenly struck by a cold and keen
air . . .
No matter how tired one is, when one reaches the top of a lofty
mountain, he is promptly refreshed; he feels nimbler, lighter; the face
is pale and the flesh less ruddy. In a word, what one feels then has
nothing in common with, or rather it is the opposite of, the effects pro-
duced upon living beings by an air which is too expanded and too rare.
(P. 123.)
He next discusses the observations of Bouguer and La Conda-
mine, and says in conclusion:
I urge physicists who have the opportunity to attempt new experi-
ments, if it is possible, to ascertain whether at certain heights the air
really becomes rare and expands to such a degree that animals cannot
ascend there without suffocating as they do in a vacuum; whether this
more or less great density is the only cause of the rising and the varia-
tions of the mercury in the barometer.
De Saussure,-4 in the first volume of his great work, after tell-
ing of his sufferings from mountain sickness during his ascent of
Buet, tries to find the reason for them. It is strange that he alludes
to the real explanation, although only to oppose it, which the
recent discoveries of Priestley and Lavoisier permitted him to
glimpse:
559. — We cannot attribute the exhaustion of muscular strength to
fatigue alone, as M. Bouguer thought. A fatigued man, on the plain
or on mountains of moderate height, is rarely so exhausted that he
214 Historical
absolutely cannot continue; whereas, on a lofty mountain, one is some-
times so exhausted that, to avoid most imminent danger, he would
literally not take four steps more, perhaps not even one step. For if
one persists in making efforts, he is attacked by palpitations and such
rapid and hard throbbing in all the arteries that he would fall in a
faint if he increased the palpitations still more by continuing to ascend.
However, and this forms the second characteristic of this strange
kind of fatigue, the strength is restored as quickly, and apparently as
completely, as it was exhausted. Mere cessation of movement, even
if one does not sit down, and in the short space of three or four min-
utes, seems to restore the strength so perfectly that when one starts
walking again, he is convinced that he will ascend even to the summit
of the mountain all in one breath. Now on the plain, a fatigue as
great as that of which we have been speaking does not pass away so
quickly.
560. — One would be tempted to ascribe these effects to the diffi-
culty in breathing; it seems natural to believe that this rare and light
air does not expand the lungs sufficiently, and that the organs of
respiration are tired by the efforts they make to supply it, or that,
since the duty of this vital function is not completely carried out, and
since the blood, according to the theory of M. Priestley, is not suffi-
ciently supplied with its phlogiston, the whole animal economy is dis-
turbed by it.
But what persuades me that this is not the real reason for these
effects is that one feels fatigued, but not at all oppressed; if the painful
action of climbing a steep slope makes the respiration shorter and
more difficult, this inconvenience is felt on low as well as on high
mountains, and yet does not produce in us, when we climb these low
mountains, the effect which we experience on those which are very
lofty; moreover, on the latter, when one is quiet, he breathes with the
greatest ease. Finally, and this consideration appears to me conclu-
sive, if it was imperfect respiration which produced this prostration,
how could a few instants of rest taken while breathing this same air
seem to restore the strength so completely?
561. — I am inclined to believe instead that these effects should
be attributed to the relaxing of the vessels caused by the decrease of
the compressing power of the air.
Because we are accustomed to living compressed by the weight of
the atmosphere, we hardly think of the action of this weight and its
effect upon the animal economy. However, if one reflects that at sea
level every part of the surface of our body is laden with the weight
of a column of mercury 28 inches high, that a single inch of this fluid
exerts upon a surface one foot square a pressure equivalent to 78
pounds, 11 ounces, 40 grains, marc weight; that consequently 28 inches
exert on this same surface the pressure of 2203 pounds, 6 ounces; and
that therefore, reckoning ten square feet of surface for a man of
average height, as is usually done, the total mass of weight which
compresses the body of this man is equivalent to 22,033 pounds, 12
ounces; if we consider what must result from the action of this
weight, we shall see that it must compact all parts of our body, that
it binds them together, so to speak, that it compresses the vessels, that
Theories and Experiments 215
it adds to the elastic power of the arteries, that it condenses the walls
of these same vessels, and resists the transudation of the more subtle
parts, the nervous fluid, for example, and that for all these reasons
it must contribute to the muscular strength.
If then one were suddenly transported from sea level merely to
the altitude of 1250 fathoms, where the weight of the air lifts only
about 21 inches of mercury, the action of the atmosphere upon our
body would be lessened one quarter, or 5508 pounds, 7 ounces; con-
sequently all the effects of this action would be considerably lessened,
and the muscular powers would necessarily suffer from it. The ves-
sels, in particular, would exert very much less pressure upon the fluids
which they contain; and for that very reason they would interfere less
with the acceleration which muscular movement tends to give to the
whole mass of our liquids.
And so in lofty regions where the vessels are only slightly com-
pressed by the pressure of the atmosphere, the efforts one makes in
climbing a steep slope must accelerate the movement of the blood much
more than in low lands, where the compression of the vessels resists
this acceleration. From that, no doubt, result the rapid throbbing of
all the arteries and the palpitations which attack one on lofty moun-
tains, and which make one fall unconscious if he persists in moving
with too much speed.
But also, through an effect of this same relaxing of the vessels,
since they react weakly upon the blood, as soon as one ceases moving,
the acceleration which had been produced by this movement ceases of
itself shortly, whereas if the vessels were greatly strained, their elas-
ticity would have perpetuated this acceleration, long after its cause
had ceased to act. That is the characteristic of weak beings, they are
easily moved, and quieted too; whereas strong beings, hard to set
in motion, are also harder to quiet. When, therefore, the vessels are
relaxed by the decrease of the air pressure, a few moments of rest
are enough to establish order and calmness in the circulation, and by
the slackening of this circulation to give a feeling of inner coolness,
which, aided by the coolness of the air which one breathes in these
lofty regions, brings complete calmness, and persuades one that the
fatigue has completely vanished. As to the drowsiness, I think that
it is the effect of the vascular relaxation, and especially that of the
brain. At least this seems to me the most probable reason for these
facts: I leave judgment of it to the professional physiologists. (Vol.
I, p. 482-488.)
And so to de Saussure it is the decrease of the pressure exerted
by the air upon the cutaneous vessels which, by lessening their
resistance to the heart impulses, causes the circulatory acceleration
and consequently all the symptoms which he observed and experi-
enced. But, after his celebrated ascent of Mont Blanc, he adds to
this explanation reflections of a value in much greater harmony
with the wisdom of his lofty intellect:
1965. — If we consider after all (he says) that the barometer at
that height stood at only sixteen inches and one line, and that there-
216 Historical
fore the air had hardly more than half of its usual density, we shall
understand that the lack of density had to be compensated by fre-
quency of inspirations. Now this frequency accelerated the movement
of the blood, all the more because the arteries were no longer com-
pressed from without by a pressure equal to what they usually ex-
perience; and so we all had fever. (Vol. IV, p. 147.)
He returns a little later to this explanation and draws conclu-
sions from it. He likewise refutes the theory of Bouguer:
2021. — Of all our organs, the one which is most affected by the
rarity of the air is that of respiration. We know that to maintain
life, especially that of warm-blooded animals, a specified quantity of
air must pass through their lungs in a given time. If then the air
they breathe is twice as rare, their inspirations must be twice as
frequent, so that the volume may compensate for the rarity. It is
this forced acceleration of respiration which is the cause of the fatigue
and the distress which one experiences at these great heights. For at
the same time that respiration accelerates, the circulation accelerates
also. I had often noticed this on lofty peaks, but I wished to make
an exact test of it on Mont Blanc; and so that the effect of the motion
of walking might not be confused with that of the rarity of the air,
I did not make my test until we had remained quiet or nearly quiet
for four hours on the summit of the mountain. Then the pulse rate
of Pierre Balmat was 98 per minute; that of Tetu, my servant, 112,
and mine, 100. At Chamounix, also after resting, the same men, in
the same order, had pulse rates of 49, 60, 72.
While there, we were all in a state of fever which explains both
the thirst which tormented us and our aversion to wine, strong liquor,
and even all kinds of food . . .
However, when we remained perfectly quiet, we had no definite
discomfort. And that is the fact which made Bouguer think that the
symptoms which one experiences in this air come only from fatigue,
for he agrees with me on all the data . . .
It seems evident to me that in explaining these data, the learned
academician made a mistake, confusing the effects of the rarity of the
air with those of weariness. Weariness does not produce the effects
of the rarity of the air. Often, in my youth, when I returned from
some long mountain trip, I felt weary to the point of not being able
to stand up any longer; in the state which Homer expressed so ener-
getically by saying that the limbs are dissolved by fatigue, and yet I
felt no nausea or faintness, and I desired restoratives, far from feeling
a dislike for them. Moreover, although these academicians often ex-
perienced great fatigue in the course of their long and painful labors,
nevertheless, to ascend Pichincha, which is particularly mentioned,
they started from Quito, which is at an elevation of 1400 or 1500
fathoms, and they went still higher on horseback. They therefore had
only 300 or 400 fathoms to make on foot, which could hardly produce
a fatigue capable of causing the symptoms which Bouguer describes.
Therefore the same muscular movement which would have produced
only moderate weariness without any symptoms in a dense air pro-
Theories and Experiments 217
duces in a very rare air an acceleration in respiration and circulation,
from which there results distress which is unendurable to certain tem-
peraments. (Vol. I, p. 207-209.)
But the first interpretation accepted by de Saussure, the de-
crease of the weight sustained, had success much above its deserts,
whereas the second, which contains, as we shall see, a part of the
truth, remained much less widely known.
Some years after him, the physiologist 25 Fodere underlined his
mistake, so to speak, comparing the hemorrhages from decreased
pressure to those which follow the application of cupping-glasses:
The atmospheric pressure keeps the vessels from being too forcibly
distended by the liquids which they contain and by the elastic force
of the air abundant there ... If this pressure is removed, or if its
intensity is merely lessened, the parts undergo considerable swelling
and hemorrhages; we have common examples of it ... in suction, in
the operation of cupping-glasses, in the hemorrhages of travellers who
ascend to the summits of lofty mountains; in the heaviness, distention
and discomfort which we experience whenever the air is lighter. (P.
220.)
Halle and Nysten 2r> share this opinion and express it with the
greatest clearness. For them, in the first place, the chief effect is
due to the removal of the weight of the atmosphere:
Whenever one places an animal under the receiver of the pneu-
matic machine, or when one mounts rapidly to considerable heights,
then not only the sudden expansion of the free elastic fluids, propor-
tional to the rapid decrease of the atmospheric pressure, but also
the tendency to expansion which exists in the animal liquids them-
selves, especially in the elastic fluids which they hold in solution, may
be the cause of several striking results, such as a feeling of general
discomfort, etc.
However, after describing the phenomena presented by travel-
lers and balloonists, the authors seem to relegate their entirely
mechanical explanation to a secondary place, for they add:
These effects are easily accounted for. On account of the decrease
in the density of the air there is a lessened quantity in the same
volume. This air, therefore, is less adequate for the combinations which
it must experience in the act of respiration; consequently, so that in
rarefied air these combinations may take place conformably to the
purpose of nature, one must breathe proportionately with greater
rapidity. This is the cause of this hasty and panting respiration and
consequently of the acceleration of the pulse rate which results from
it. We even comprehend that at much greater heights the rarefaction
of the air would be such that acceleration of the respiration would
218 Historical
not suffice to bring to the lungs the quantity of air necessary for the
maintenance of life, and that life would finally be extinguished, as it
is in asphyxia, for lack of the principal agent of respiration. Death
in this case might be preceded by various phenomena unrelated to
respiration, such as emphysema and different hemorrhages due entirely
to the great expansion of all parts of the body.
Here again we find, applied to respiration, the explanation
already given by de Saussure; as to hemorrhages, Halle and Nysten
persist in attributing them to the decrease of the weight sustained
by the body.
The same combination of explanations is expressed with greater
clearness and moderation in the thesis of Courtois: 27
Most of these phenomena depend at the same time upon changes
which occur in the weight of the air and upon the varying quantity of
oxygen which this fluid contains in the same volume, depending upon
whether it is condensed or rarefied; thus chemical phenomena compli-
cate those which depend upon the weight of the air. (P. 17.)
At the same epoch there appeared a remarkable work, which
deserved more attention from physiologists, and which nevertheless
remained almost completely unknown, at least in the part which
interests us. I must even confess, not without some embarrass-
ment, that I did not know of its existence until I was doing biblio-
graphic research necessary for the preparation of the first part of
this work, after all my experiments had been completed.
In his researches on animal heat, Legallois 2S was led to compare
the variations in temperature of warm-blooded animals with the
quantity of oxygen which they absorb in a given time. Among
the causes which might act upon this absorption, he considers the
rarefaction of the air, as a means "of lessening the quantity of
oxygen contained in the air in which the animal is confined".
Legallois kept the animals in closed vessels (the manometer, as he
calls it, measured 41 liters) during the whole experiment; he has
nowhere specified the degree of decompression to which he had
subjected them, but it is easy to conclude from his accounts that
he never reached a half-atmosphere. I summarize in the following
table the results of his experiments; the comparative test, made for
each animal at normal pressure, lasted the same time, of course:
Theories and Experiments
219
Change in
Oxygen Carbonic body
consumed acid jormed temperature
1. Rabbit, normal pressure 7.05 6.16 + 0.2°
Rabbit, rarefied air 6.43 5.02 — 2'°0
2. Rabbit, normal pressure 6.53 6.56 + 0.3°
Rabbit, rarefied air 5.97 4.56 — 2.2°
3. Rabbit, normal pressure 12.08 8.55 — 1.3°
Rabbit, rarefied air 9.96 7.60 — 1.3°
4. Cat, normal pressure 9.50 — 0.5°
Cat, rarefied air 6.93 — 4.2°
5. Cat, normal pressure 8.52 6.20 — 0.3
Cat, rarefied air 7.66 6.12 — 7.°^
6. Dog, normal pressure 13.26 9.12 — 1.7
Dog, rarefied air 10.91 9.11 — 4.2°
7. Dog, normal pressure 13.19 7.65 — 4.
Dog, rarefied air 10.39 6.63 — 6.2°
8. Guinea pig, normal pressure 8.49 6.27 — 0.4
Guinea pig, rarefied air 7.37 6.56 — 2.6°
9. Guinea pig, normal pressure 11.41 9.10 — 1.3
Guinea pig, rarefied air 9.58 8.42 — 4.8
Legallois draws from these experiments, in reference to the
subject which interests us here, the following conclusion, which
shows admirable sagacity:
Since the mere rarefaction of the air, carried far enough to lower
the barometer less than 30 centimeters, is enough to chill the animal
which breathes it, the result is that the cold experienced on lofty
mountains does not depend solely on the coldness of the atmosphere,
and that it has in addition an inner cause, which acts through respi-
ration. (P. 59.)
What a contrast between these clear experiments, these precise
conclusions and the confused mass of so-called explanations which,
in that same year, Dralet -n gave both of the discomforts and the
improved conditions experienced on lofty places!
The air on mountains of moderate height is more healthful than
that on the plains ... If we consider, moreover, that the pressure of
the atmosphere is less as we ascend, we shall not be surprised that
the dwellers on the plain are in better health on the Pyrenees, eat
with more appetite, and that the elasticity of their lungs gains new
strength there.
But the man who is approaching the region of snow will not find
an air so favorable to the animal economy; since vegetation, accord-
ing to the observation of M. Ramond, is practically absent from these
wild spots, the nitrogen is not absorbed by the organs of plants, and
lessens the wholesomeness of the air by its abundance.
MM. Vidal and Reboul have proved that the quantity of vital air in
the atmosphere at the summit of the peak of Midi in Bigorre was about
220 Historical
one-fourth less than in the valley. Moreover, as the weight of the
atmosphere decreases in proportion to the height of its strata, when
a man has reached the summit of a lofty mountain, all the parts of
his body, since they no longer receive sufficient pressure from the
surrounding air, must yield to the heat which expands them in seek-
ing its equilibrium in the surrounding bodies. The result is relaxation
in the fibre, softening in the solid parts, and excess of fluidity in the
liquids.
So persons who travel on lofty mountains are subject to hemor-
rhages, vomiting, and fainting; but these symptoms rarely appear un-
less one ascends to 2000 fathoms above sea level. (Vol. I, p. 36.)
Gondret 30 was no more fortunate when he tried to give "an ex-
planation, if not complete, at least satisfactory", of the symptoms
observed during mountain ascents. This is what he says:
The decrease of the weight of the column of air and the elasticity
of our organs explain the turgidness of the body, the expansion of the
vessels and fluids, and consequently the hemorrhages.
The lungs, accustomed to 18 or 20 regular inspirations and expira-
tions per minute, suddenly forced to multiplied movements in order to
absorb the same quantity of air, are extraordinarily hasty in their
labor.
The heart immediately feels the effect of the hasty action of the
lungs; the result is an accelerated pulse rate and lipothymies.
When the two effects which the heart and the lungs exert on the
brain are thus accelerated, we can imagine the changes that take place
in this organ, and consequently in its functions; it is to these changes
that we can attribute the vertigo, dizziness, syncope, and all the dis-
orders which follow.
The differences noted in different individuals in the intensity of
the symptoms are the result of idiosyncrasy. (P. 40.)
However, we must admit that he was the first to have the idea
of applying rarefied air to therapeutics. From the very evident
effect exerted upon us by changes in the barometric pressure, he
derives this suggestion:
Perhaps chambers may be constructed in such a way that, by the
help of the pneumatic pump, we may introduce into them a more or
less dense air, according to the requirements of the case. (P. 45.)
The rest of the volume is devoted exclusively to the study of
the effect of cupping-glasses, simple or combined with scarification.
The English travellers who, at the beginning of this century,
journeyed over the lofty regions of India, introduced a new ele-
ment into the explanation of mountain sickness. According to their
stories, the natives of these countries attribute the disturbances
which attack strangers and the natives themselves to the effect of
Theories and Experiments 221
a poisoned wind; generally, the emanations of certain plants are
supposed to give these toxic qualities to the air.
Fraser 31 is the first to give us this curious information; we
must admit that he makes haste to reject this explanation, and for
an excellent reason:
I did not suspect that the altitude could affect the strength and
the lungs so severely, and yet it was the only cause, no matter how
difficult the ascent; for in that respect we had had days before that
were at least as bad; and although we were told that the air was
poisoned by the odor of flowers, and although there were indeed a
profusion of them during the first part of our journey, most of them
had no odor, and we could not perceive any in the air. More than
that, we were particularly distressed when we reached the lofty gorge
of Bamsooroo, where there was no vegetation, and consequently no
perfume of flowers. (P. 449.)
Dr. Govan,3- who accompanied Captain Al. Gerard on his first
journey in 1817, reports the same tradition, without giving it any
more credence. But much astonished by the lack of proportion
already noted by travellers between the altitude and the intensity
of the symptoms, he has the peculiar idea of having electricity play
an active part in these phenomena:
On the highest peaks of the mountains of Choor there first appear
the juniper-tree, the alpine rhododendron, and the tall aconite, the
toxic effects of which, when it is used internally, are well known, and
seem to have given rise to the belief common among the natives that
it poisons the surrounding air; I can find no basis for this opinion,
except that in the lofty places in which this beautiful plant grows,
travellers often, but not always, experience disagreeable symptoms,
usually attributed to the expansion of the air.
If the symptoms considered by eminent naturalists as resulting
from this expansion should really be ascribed to it, why are they not
proportional to the elevation and the rarefaction, and why do these
symptoms not invariably appear when the elevation and rarefaction
reach a certain degree?
On two occasions I passed the night at elevations more than
14,000 feet above the line of perpetual snow; I crossed the Rol-Pass
(much above 15,000 feet), accompanied by 40 native soldiers, without
anyone of us experiencing these painful symptoms. Now, in the same
places, and even at lower elevations, they have been observed in other
ascents and predicted in advance by the natives.
All of this seems to indicate that these symptoms result from less
general atmospheric circumstances, such as the electric force, which,
in the case of such lofty conductors, must be in a state of constant
fluctuation. (P. 282.)
Captain Al. Gerard,13 in the account of his journey of 1818, also
mentions poisonous plants:
222 Historical
I should note that the inhabitants of Koonawur estimate the height
of mountains by the difficulty in breathing during the ascent of them,
which difficulty they attribute to a poisonous plant; but in spite of
our search in each village, we found no one who ever knew this
plant, and judging by our experience, we are inclined to attribute
these effects to the rarefaction of the atmosphere, for we have ex-
perienced them at elevations where there was no more vegetation.
(P. 49.)
He alludes again to this hypothesis in his book on the country
of Koonawur,34 but always to reject it:
Travellers crossing these ranges attribute these painful effects to
the influence of poisonous plants; but better informed persons, who
customarily pass over these heights where there is no vegetation,
know very well that they are produced entirely by the altitude. (P.
37.)
But in narrating his expedition and his stay at the pass of
Shatool (4830 meters), Dr. Gerard3" does not give any heed to
the explanation of the natives. He suffered greatly, as the account
which we reported above proves, and naturally sought the cause of
his distress, but without success; but in the meantime, he opposed
the skepticism of those who for some reason experienced no symp-
toms:
There I had a lesson which I shall never forget, and I am sure
that a man of a more plethoric constitution would have died from
apoplectic suffocation. The blood left my extremities, and the pres-
sure on the surface of the body was so diminished in that rarefied
air that the blood rushed to the head and produced vertigo. (P. 308.)
The cause of the symptoms is not very easily seen, and these
extraordinary indications of loss of strength, distress, and mental
weakness are not satisfactorily explained, and although we cannot
hesitate to attribute the principal and immediate cause of them to
the rarity of the air, or, more exactly, to the diminished pressure,
by which the balance of the circulation is destroyed, nevertheless, the
effects are so capricious and irregular that they can hardly agree with
the idea of a constant cause. This leads travellers even to deny the
existence of the symptoms, and those who have by chance resisted
this effect while crossing the mountains remain firm in their convic-
tion; but I know that you will believe my reports, although you had
only a headache on Boorendo. I too passed the night here without
any symptom, except weakness. (P. 320.) . . .
As respiration cannot take place in a vacuum, we must consider
that, at the elevation of 18,480 feet (5630 meters), the air is nearly
half exhausted, and as the whole can have only the sum of the effects
of its parts, the progressive action here becomes an arithmetical series,
reducible to an experiment in physics, in which the piston strokes of
a pneumatic pump seem to draw the hand placed over the opening
Theories and Experiments 223
more and more, until the greater pressure is so much more than the
lower pressure as to be unendurable to the experimenter. At 18,480
feet, the barometer stands on the average, at 15 inches, so that we then
breathe an air only half as dense as that at sea level; who could be
surprised at the effects observed? (P. 323.)
Captain Hodgson,36 who in his turn reports the statements of
the natives, seems not far from believing them himself:
The mountaineers, who know nothing of the rarefaction of the
air, attribute their weakness to the exhalations of harmful plants, and
I think that they are right, for a sort of unwholesome effluvium was
exhaled by them here as Well as on the heights below the snowy
peaks which I crossed last year on Setlej; although, on the highest
snow, the complaint was not of weakness, but of the impossibility of
walking for some time without stopping to breathe. (P. 111.)
We shall see later, by the testimony of recent travellers, that
this idea of wind poisoned by plants is today quite popular in
Upper Asia.
If now we return to our Alps, about this same time we find
Hipp. Cloquet37 republishing the mechanical explanation:
The pressure of the air, which weighs constantly upon us from
all sides . . . seems necessary to the maintenance of the equilibrium
between the living solids and the humors which circulate or float
within them; it counterbalances the elastic force of the fluids of our
bodies; and since this pressure is considerably diminished here, it is
not surprising that the equilibrium is ruptured. (P. 36.)
Dr. Hamel,38 when he undertook the fatal expedition on Mont
Blanc in 1820, had planned to make experiments there; one of his
plans gives evidence of a remarkable sagacity and shows very
definite and very scientific hypothetical views about the cause and
the effects of rarefied air:
I had prepared a flask of lime water to see whether, at the sum-
mit, the expired air was laden with carbon in the same proportion as
in the regions where at every inspiration about one-third more oxygen
enters with the same volume of atmospheric air. I also planned to
extract, on the summit, the blood of some animal, to see by its color
whether it had been sufficiently decarbonated in the lungs.
The account of the ascent of Mont Blanc carried out by Clis-
sold 3n in 1882 brings us to an explanation which had not appeared
up to that time, and which might serve as type for that physiology
of probabilities which has done such harm to science.
In the first place, Clissold attributes the symptoms observed to
the smaller quantity of oxygen contained in the same volume of
air, which compels respiration to be deep and hasty.
224 Historical
On the other hand, since muscular energy in general is dimin-
ished, the lungs expand less, and compensation must be made by
greater frequency of inspirations. Then the editor of the Biblio-
thcque universelle adds:
Clissold here suggests, without developing it, one of the causes to
which we should be tempted to attribute the greatest influence upon
one of the effects noted; we mean the expansion undergone by the air
enclosed in the abdominal cavity, as one rises in the atmosphere; this
expansion, by raising the diaphragm, lessens by so much the capacity
of the thoracic cavity, and does not permit the lungs to expand as
much as usual, until, by certain slow communications with the ex-
terior, equilibrium between the abdominal and thoracic cavities is
established again, and the latter regains its ordinary capacity.
The French naturalist Roulin,40 who spent several years fn Bo-
livia, in 1826 sent to Magendie a letter containing observations on
the pulse rate, made on the same persons at Guaduas (average
pressure 718 mm.) and at Santa-Fe-de-Bogota (560 mm.; 2643
meters above sea level) . They show a slight increase in the pulse
rate in the latter place. The difference is rather slight, and M.
Roulin concludes from this:
According to that, we may assume that the effects felt when one
ascends lofty mountains and attributed entirely to the decrease of
pressure, when they are not due to cold or the fatigue of the ascent,
must be considered chiefly as nervous phenomena.
And yet, a few pages farther on, the author adds:
The difficulty in breathing which I felt on the plateau of Bogota
was at first attributed to the state of my health; but I observed that
several persons, who had recently arrived on the plateau, also com-
plained of this difficulty.
It is evidently rather because of the name of their author than
because of their own importance that I have quoted these observa-
tions; they are anything but conclusive.
It is also from the standpoint of curiosity that I report here
the conclusions from a work of John Davy 41 upon the gases of the
liquids and the solids of the body; it is a real step backward from
what Robert Boyle and Darwin had taught us. But the reader may
judge from that the hesitations between which the minds of physi-
ologists drifted.
J. Davy carried out numerous experiments with the purpose of
finding out whether the liquids or the solids contain gases which
the pneumatic pump can extract. The results obtained were always
negative, and he concluded from that that there are no free gases
Theories and Experiments 225
in the blood, which, moreover, would be "unchemical" and incom-
patible with life, for at the slightest increase in temperature or
decrease in pressure, nothing could prevent the escape of these
gases.
It is curious to see, a few years afterwards, a celebrated French
physician, Rostan,42 appeal to the very influence of these gases,
though vaguely, it is true, to explain the symptoms of decompres-
sion. He mingles with his discussion the mistaken ideas, which we
have already met and which we shall often find again, about the
part played by the decrease of the weight sustained by the body:
If one places a living animal in a vacuum, the air within, having
nothing to resist it, expands, the animal swells up and dies ... It is
the pressure of the air which keeps the fluids in the vessels of animals
and prevents them from escaping. When the barometer drops a few
degrees, the fluids press towards the periphery; there is difficulty in
breathing, disturbance of the circulation, and congestion towards the
head. (P. 340.)
About this same time there appeared an English memoir which
at least had the merit of originality, in the sense of oddness. Cun-
ningham,43 as Govan had already done, makes electricity play a
principal part, thus explaining the unknown by the unknown; but
he adds a strange idea; that there is a radical difference between
the effects of the ascent of mountains in the two hemispheres:
Apoplectic symptoms characterize the distress of travellers on
Mont Blanc, whereas in the southern hemisphere the threatening
symptoms are all those which accompany syncope . . .
The first have been attributed to the great rarefaction of the air
which permits the soft parts of the human body to expand as a result
of the reduction in the pressure exerted upon them; but since a similar
elevation in the Andes produces effects of an opposite nature, we
should seek to explain the latter by other causes than the rarefaction
of the air.
This cause the author finds in electricity,
Which occupies, in the northern hemisphere, the upper part of the
body, and, in the southern hemisphere, the lower part, and thus tends
to draw the blood towards the head in the former, and towards the
feet in the second . . . which also explains why the distress is re-
lieved by the horizontal position.
We think it useless to continue any farther, and we shall also
report without comment the few lines which Burdach,44 in his im-
mense encyclopedia, devotes to the effects of a decrease in pressure
upon the organism; we see clearly by what he says that he
226 Historical
attributes them to the lack of the support of the air upon the
blood vessels:
The pressure of the atmosphere (he says) upon the human body
is equal to a weight of 30,000 to 36,000 pounds; it keeps the mechanical
arrangements of the organism in their normal state, and gives con-
siderable help to the circulation, restraining the flow of the blood
towards the surface . . . Symptoms caused by congestions in various
organs have sometimes been noted on lofty mountains, where the air
is greatly rarefied. (P. 325.)
One of the great difficulties always encountered by authors is
the lack of proportion between the severity of the symptoms and
the elevation which the travellers have reached, and that not only
in different hemispheres, but in the same country, on the same
chain of mountains.
That is why the German Poeppig,4"' who gave such a complete
description of the mountain sickness of the Andes, cannot make
up his mind that the cause of it is the decrease of the atmospheric
pressure:
The idea that the Puna, the Veta, does not depend upon the rare-
faction of the air, but upon a change in its composition, finds support
in the observation that the illness is not always in proportion to the
elevation of a place above sea level. The cabin of Casacaucha is
nearly at the same level as Cerro de Pasco, the pass of Viuda is a
thousand feet higher, and I have never felt the slightest distress there.
(Vol. II, p. 84.)
M. Boussingault 46 also was struck by these variations; but bolder
than Poeppig, he seeks an explanation of them:
In all the excursions I undertook in the Cordilleras, I always felt,
at an equal height, an infinitely more painful sensation when I was
climbing a slope covered with snow than when I was mounting over
bare rock; we suffered much more in scaling Cotopaxi than in ascend-
ing Chimborazo. On Cotopaxi we were constantly mounting over
snow.
The Indians of Antisana assured us also that they felt stifled
(ahogo) when they walked for a long time over a snowy plain; and I
confess that after considering carefully the discomforts to which de
Saussure and his guides were exposed when they bivouacked on Mont
Blanc, at the moderate height of 3888 meters, I am disposed to attribute
them at least in part to the still unknown effect of snow. In fact, their
bivouac did not even reach the elevation of the cities of Calamarca
and Potosi.
In the lofty mountains of Peru, in the Andes of Quito, the travel-
lers and the mules which carry them sometimes suddenly experience
a very great difficulty in breathing; we are told that animals have
been seen to fall in a state very like asphyxia. This phenomenon is
Theories and Experiments 227
not invariable, and, in many cases, it seems independent of the effects
caused by the rarefaction of the air. It is observed particularly when
abundant snows cover the mountains and the weather is calm.
Perhaps this is the place to note that de Saussure was relieved
of the distress he felt on Mont Blanc when a light north wind arose.
In America, the name soroche is given to this meteorological state of
the air, which affects the organs of respiration so greatly. Soroche,
in the language of the American miners, means pyrites; this name
shows plainly enough that this phenomenon was attributed to sub-
terranean exhalations. The thing is not impossible, but it is more
natural to see in the soroche an effect of the snow.
The suffocation which I felt several times myself while I was
mounting over snow, when it was struck by rays of the sun, made
me think that air which was evidently foul might escape from it as
an effect of the heat. What supported me in this strange idea was a
former experiment of de Saussure, in which he thought he observed
that the air which escaped from the pores of the snow contained much
less oxygen than the atmosphere. The air subjected to examination
had been collected in the interstices of the snow on the col du Geant.
Analysis of it was made by Sennebier, by nitrous gas and in compari-
son with the air of Geneva. (P. 167.)
M. Boussingault then repeats the experiment of Sennebier with
the snow which he had taken from Chimborazo. Ordinary analysis
gave him only 16% of oxygen. But the celebrated chemist him-
self declares that objection may "strictly" be made to his method;
since the snow had melted in the bottle, the air, in the presence
of water only slightly aerated, might have given it part of its
oxygen. Evidently that depends upon the quantity of air in pro-
portion to the quantity of water, a proportion which is not given
in the work from which we quote.
But later, M. Boussingault, having taken up this question again,47
showed that the apparent lack of oxygen in the air contained in
the pores of the snow results from the fact that the oxygen is dis-
solved in greater proportion than the nitrogen in the water of
fusion. There is nothing left then of his first hypothesis.
These contradictory results, due to the improvement of methods
of chemical analysis, remind us of the different opinions expressed
in 1804 and 1837 upon the same subject by the illustrious von Hum-
boldt.
In the letters which he wrote to his brother and Delambre,
immediately after his ascents of Antisana and Chimborazo, von
Humboldt declared that in his opinion
The distress, the weakness, and the desire to vomit certainly came
as much from the lack oi oxygen in these regions as from the rarity
of the air. He had found only 0.20 of oxygen at 3031 fathoms, on
Chimborazo. (P. 175.) "
228 Historical
And yet, it appears from his letter to his brother40 that the
same symptoms attacked him on the summit of Antisana, where,
however, analysis showed them the normal proportion of 0.218 of
oxygen in the air.
But when, in 1837,50 he refers to the details of his account, he
no longer speaks of the chemical composition of the air, but only
of the lessened quantity of oxygen in the same volume; further-
more, he introduces into science a new explanation of the fatigue
on mountains, an unsatisfactory explanation, which, however, was
long accepted without contradiction:
According to the present state of eudiometry, the air seems as
rich in oxygen in these lofty regions as in the lower regions; but in
this rarefied air, since the barometric pressure is less than half what
we are ordinarily exposed to on the plains, a smaller quantity of
oxygen is received by the blood at each aspiration, and we understand
perfectly why a general feeling of weakness would result. This is
not the place to inquire why this asthenia, on the mountains as in
vertigo, usually causes uneasiness and a desire to vomit, nor is it the
place to demonstrate that the issue of blood or bleeding from the lips,
the gums, and the eyes, not experienced by everyone at such great
heights, can by no means be explained satisfactorily by the progressive
removal of a mechanical counterweight which compresses the vascular
system. It would be better to examine the probability of the effect of
a lessened air pressure upon weariness when the legs are moving in
regions where the atmosphere is greatly rarefied; since, according to
the memorable discovery of two clever scholars, MM. Guillaume and
Edouard Weber, the leg, attached 51 to the body, is supported when it
moves, only by the pressure of the atmospheric air. (P. 419.)
If M. Gay-Lussac, who on September 16, 1804, reached the prodi-
gious height of 21,600 feet, which consequently was between that of
Chimborazo and Illimani, did not suffer from bleeding, perhaps that
should be attributed to the absence of all muscular movement. (P.
418.)
About this time, a French physician, Dr. Junod,"'2 conceived and
carried out the idea, already glimpsed by Gondret, of lowering the
pressure artificially in apparatuses large enough to accommodate a
man.
M. Junod had been led to make his experiments by the effects
"he felt from the expanded air in the Alps, in the Pyrenees, and
on Mount Etna. His apparatus consisted of a copper sphere 1.30
meters in diameter, in which a man could sit:
When a person is placed in the interior of the receiver, and the
natural pressure of the air is lessened one-quarter, this is what one
observes:
1. The membrane of the tympanum is distended, which causes a
Theories and Experiments 229
rather uncomfortable sensation, which disappears as equilibrium is
reestablished;
2. Respiration is hampered: the inspirations are short and fre-
quent after 15 or 20 minutes. A true dyspnea follows this difficulty
in breathing;
3. The pulse is full, easily depressed, frequent; all kinds of super-
ficial vessels are in a state of manifest turgescence. The eyelids and
the lips are distended by the superabundance of fluids. Not infre-
quently hemorrhages occur, with a tendency to syncope. The skin is
the seat of distressing heat and its functions are increased;
4. The slackened formation of blood, the expansion, more or less
great, of the gases which circulate with the blood, and the super-
abundance of this liquid in the different classes of superficial vessels,
explain well enough the failure of innervation which is characterized
by lack of energy and a complete apathy;
5. The salivary and renal glands secrete their fluids less abun-
dantly, and this effect seems to extend over the whole glandular
system;
6. The weight of the body seems to diminish perceptibly.
The memoir ends with the description of the large cupping-
glasses and of some pathological cases treated with them. To the
application of this method of treatment, to which he has given the
name of hcmospasie, M. Junod has devoted his efforts since that
time.53 It really has no connection with our subject, since it con-
cerns a rupture of the equilibrium of pressure between different
points on the body, by the application of a partial vacuum on one
or several members. Magendie first made this evident in the re-
port 54 which he was requested to present to the Academy of Sci-
ences upon the work of M. Junod.
The celebrated physiologist first reviews the history of cupping-
glasses, which date from the time of the Egyptians, and passes to
the barometric chambers of M. Junod by a transition which shows
that, in spite of himself, he still compares them with these cup-
ping-glasses:
These apparatuses (he says, in fact) were constructed with the
purpose of varying, upward or downward, the pressure which the
body of man sustains through the extent of its cutaneous and pulmo-
nary surfaces . . .
It is by acting upon the two surfaces at the same time that this
apparatus differs from those which were devised in England by MM.
Murray and Clanny; these apparatuses last mentioned act exclusively
upon the skin, the lungs having free communication with the outer air,
through a separate tube.65
Then, to come to the part of M. Junod's work which has some
interest for us, Magendie quotes the report of the phenomena pre-
230 Historical
sen ted by a man subjected to the action of compressed or ex-
panded air; we have just taken from the original memoir what
relates to this last point.
We regret to add that Magendie did not display much fore-
sight when he said:
From a medical point of view, these apparatuses as yet do not
seem to offer any application . . . That is not true, however, of those
which M. Junod designs to use for rarifying or compressing the air
around members.
It is not surprising to note that after these discouraging re-
marks M. Junod gave up the use of expanded air as a general
medium, and limited himself to improving 56 the large cupping-
glasses which bear his name, a very powerful therapeutic agent
which has very unjustly been neglected by physicians. But through
a strange confusion, explanations which were very appropriate
when it was a matter of the local rarefaction by the large cupping-
glasses continued to be applied to the general action of decreased
pressure. As an example of this mistake, I shall quote the remarks
of Dr. H. Favre: 57
The principles upon which the Junod method rests are very
simple:
M. Junod, born in the Alps, had himself felt the difference in
pressure as one ascends or descends in the mountains. He resumed
the experiments of de Saussure and Gay-Lussac with the most laud-
able discernment.
If one ascends to the summit of Mont Blanc, or rises in a balloon
to a height of 7000 meters, he feels remarkable effects, resulting solely
from the lack of pressure exerted at these heights by the more and
more rarefied atmosphere.
Artificially, we know how, by making a vacuum, to rarefy the
air, that is, to lessen the pressure on a circumscribed area. If we are
dealing with a living body, certain effects produced by an ascent in
the atmosphere will then appear: such is the purpose of hcmospasie;
Dr. Junod attains it by the creation of his large cupping-glass. (P. 7.)
Returning now to mountain travellers, we find again the series
of mistaken preconceptions and apparent contradictions which we
have already noted. The difficulty of explaining the facts brings
many of these travellers to deny them. An example of these
theoretical protests is furnished us by the editor of the Biblio-
thcque universelle of Geneva, who reviewed the account of the
ascent of Mont Blanc by Dr. Barry:
The circumstances observed by M. Barry are so unimportant that
they confirm us in the opinion that fatigue plays a greater part than
Theories and Experiments 231
the rarity of the air or the supposed influence of snow . . . We can
assert that these are the same sensations felt by ordinary travellers
when they approach the summit of any mountain whatsoever.
I beg the reader to refer to the actual words of Barry, which I
quoted previously (See page 95) ; he will find, I hope, in them a
proof of the necessity of verbatim quotations.
It is interesting to note that M. Martins,59 who was later to
become so sick on Mont Blanc as if by a kind of punishment for
his skepticism, at that time shared these sentiments. Accounts of
mountain sickness left him very incredulous:
As for us (he says), occupied night and day with our observa-
tions, we also tried to test our sensations to find out whether this
lofty habitation (2680 meters) had any physiological effect upon our
organs. But it was in vain . . . Since my sojourn there, I have read
again all the accounts of ascents of Mont Blanc, from de Saussure to
Mile. d'Angeville, and the sensations felt by these travellers can be
explained very easily by fatigue . . .
Of course the air of the mountains is more rarefied, but it is also
more alive . . . The liveliness of the air, added to its rarity, refreshes
the traveller and doubles his powers; for the chemical composition is
the same. (P. 213.)
I confess that I am surprised that a man with so clear and so
perspicacious a mind could have used such expressions. What do
the words "a more alive air" mean.? The Swiss peasants who saw
the celebrated professor of Montpellier collecting air in balloons
and sending it to Paris, and who thought that he would make some
illustrious patient breathe it, shook their heads and said: "Our air
will be dead when it gets there." We see that essentially they
thought like M. Martins.
Dr. Rey,G0 whose work is often quoted, and who, without seem-
ing ever to have made an ascent, wrote a dogmatic article about
mountain sickness, reaches the theoretical explanation after an
enumerative description. He sees, and in this he does not have
the merit of invention, that rarefied air is the cause of all these
symptoms:
It is neither the fatigue which removes the power of breathing,
nor the difficulty of breathing, nor an incomplete respiration which
cause the exhaustion, as has sometimes been said; it is the decrease
in the density of the air . . .
These effects are due to the relaxation of the fibre caused by the
decrease of the compressing power of -the air, the explanation of
which follows. (P. 334.)
The usual calculation on the difference in the weight sustained
by the body at different altitudes follows. At the Saint Bernard
232 Historical
pass, "the action of the atmosphere is diminished one quarter or
5500 pounds, which expands the vessels in a similar proportion".
Then, to the explanations "furnished by science" Rey adds one,
which I cannot help finding rather queer:
We can hardly climb to the top of a very lofty tower without
making frequent pauses on the way, and usually we reach the top only
with great effort. Certainly that is not because of the rarefaction of
the air, nor even because of weariness. Is it not because we have had
to lift our legs many times consecutively, by a law quite different
from that of walking and much harder to obey? In fact, all the
muscles of our organs of locomotion, set to work at the same time by
an ascensional movement to the continuity of which they are not
accustomed, experience from it a fatigue which forces us to pause
frequently, which increases as long as we continue ,t° mount, but
which ceases as soon as we have reached the top and does not return
while we are taking the same way downward. Well, that which takes
place in a man climbing a stairway he experiences with greater reason
on the side of a rugged mountain, because here there is a combination
of a long walk on trails often requiring violent and unaccustomed use
of muscular powers and a great rarefaction of the atmospheric air.
If we could wind around Mont Blanc and reach its crest by a gradual
slope as we wind around the Saint Gothard or the Simplon pass, it
would no longer be necessary to make the unnatural movement of
the legs, members which become heavier to raise in proportion to the
contraction of the column of the air, and consequently we should no
longer feel this distress which we mistake for fatigue. (P. 335.)
Tschudi,61 the celebrated. German traveller whose complete de-
scription of the mountain sickness in the Cordillera of the Andes
we have already quoted, explains the extreme weariness of the
lower limbs which one experiences in ascending, like von Hum-
boldt and the Weber brothers:
Since the head of the femur, according to the researches of Weber,
is held in its cavity by atmospheric pressure, when this pressure di-
minishes, a continuous muscular contraction must replace it. (Vol. II,
p. 66.)
He then reports, but without seeming to believe it, the explana-
tion given by the Indians about metallic emanations:
There are places where it is known that the Veta is more severe
than elsewhere, and they are sometimes lower than others where it
is much less evident, so that it does not seem to be caused entirely by
the rarefied air, but also by some unknown climatic influence. Usually
these places are rich in minerals, whence comes the general belief of
the Peruvians that these effects are due to metallic emanations.
Dr. Archibald Smith G2 does not consider these differences; but
Theories and Experiments 233
he gives some very strange information about the symptoms of
the Veta and their possible causes:
The inhabitants of the coast, when they climb the chain of the
Andes, feel their respiration oppressed in places where the Indians
do not experience this distress, because of the much greater develop-
ment of their respiratory organs ....
The pulse accelerates and the lungs act much more rapidly than
normally. Their free play is hindered, however, by the accumulation
of blood and a considerable degree of congestion, resulting, in my
opinion, on the one hand from the lessened atmospheric pressure,
which causes an expansion of the fluids in circulation, and on the
other hand from the resistance of the cutaneous and pulmonary
capillaries enlarged by the cold.
The result of this is that strangers to these climates are very
subject to stomach disturbances, dyspnea, apoplexy, or other hemor-
rhages when they cross the passes of the Cordilleras . . . Cats which
have been taken to the snow line and have been well-fed are very
subject to sudden death ... I have heard that at Cerro de Pasco a
terrier suddenly fell dead, probably from apoplexy, while he was
jumping with joy and caressing his master. (P. 356.)
An English traveller, Hill,03 who was quite sick while crossing
the Andes, and who saw two children stricken with the soroche
so violently that they "were almost lifeless in the arms of their
father", lays stress upon the effect of different temperaments in
reference to the severity of the illness:
The illness, in its most serious form, is accompanied by very
alarming symptoms and is generally fatal; in a traveller of a plethoric
constitution it is usually very serious; it is characterized then by
vertigo, weakness of vision and hearing, and very often by a flow of
blood from the eyes, the nose, and the lips and by violent headaches
and vomiting.- But in thin travellers, not very strong in constitution,
it is more likely to cause fits of weakness, accompanied by the spitting
of blood. In persons who enjoy good health, vomiting is one of the
most frequent symptoms, and the others generally consist of lassitude
and difficulty in breathing, such as appeared in my companions and
myself. (P. 68.)
Coming to the causes of the symptoms, he repeats, without seem-
ing to attach real importance to it, the opinion of the natives about
metallic emanations:
This illness has been noted to be more common in the provinces
where metals abound; so the general opinion among the natives is
that it owes its appearance or its increase of violence to the metallic
exhalations which are supposed to saturate the atmosphere of those
regions. This opinion is undeniably based on the fact that the disease
particularly attacks prospectors for metals, men who are usually not
234 Historical
accustomed to the air of the mountains, and who endure great
fatigue.
We can hardly doubt that, whatever the form under which it
presents itself, its appearance is due to the decrease in the weight of
the air, whose effect everyone feels in very lofty places. (P. 69.)
Hill does not hesitate to declare that animals can become almost
completely acclimated to lofty places:
The effects of the rarefied air are not limited to man; they exert
equal, if not greater, action upon the other animals of creation. The
horses and the mules of the plains cannot cover the same distance in
a given time on the mountains as on the plain; they are not capable
of carrying as heavy burdens on the Sierra as in the climates in which
they are accustomed to living.
However, these animals, when they have been taken to consider-
able heights and are well cared for, become acclimated, in most cases,
after a few months, and they become fit to do almost the same work
as animals born in these lofty regions. (P. 69.)
The physiologists continued, nevertheless, but without great
success, to seek for the causes of these symptoms noted, explained,
or denied by travellers. One of them, M. Maissiat,64 whom his pro-
found knowledge of physics has often inspired to better result, tak-
ing up an explanation which we have already seen mentioned by
Clissold, in 1822, gives an important part to the abdominal gases,
expanded by the decrease in pressure:
Their pressure stimulates the diaphragm and regulates the fre-
quency of its contractions; therefore, the circulation is linked with
the production of the intestinal gases. (P. 253.)
If the pressure enveloping the animal diminishes, there will be
acceleration of the circulation and respiration and congestion of the
skin, and if the pressure continues to diminish, delirium or even death
may result; since the pressure of the abdominal 'gases increases in
its effects proportional to the decrease in the outer pressure, these
gases expand and distend the entire abdomen even to the point of
rupture, if the drop in external pressure is very rapid ....
The accelerated circulation and respiration tend to speed up the
abdominal action, and thus to restore equilibrium and quiet regu-
larity. (P. 254.)
The German physician, Flechner,*55 reports an opinion quite con-
trary to that of Boussingault and von Humboldt upon the compo-
sition of the air of lofty places; he opposes it, it is true, and pre-
fers the last idea suggested by de Saussure. I quote from the
review in Schmidt's Jahrbuch:
According to the general opinion, the air in the mountains is
richer in oxygen, from which inflammatory diseases result ....
Theories and Experiments 235
Flechner has found that that is not correct .... But if, in lofty
places, the air is rarer while the composition remains the same, the
oxygen will weigh less: it will furnish less oxygen to the blood.
The light of the sun has no effect.
All the rest of the work is devoted to considerations of the
diseases which are prevalent in the mountains.
The professor of Lyons, Brachet,00 in the special work which he
devoted to our subject, begins by repeating the common idea of the
decrease of the weight sustained by the body when the air expands:
A column of air which raises the barometer only to 13 ¥2 inches
must exert upon the body and all the surfaces with which it is in
contact an infinitely smaller pressure, the effects of which we can
compare to those of the immense cupping-glass of Dr. Junod and which
we might, consequently, consider as a sort of suction. The capillaries,
which are less compressed, must therefore react less energetically
upon the blood and the other liquids which circulate through them;
they must therefore be distended and congested by a sort of stasis ....
The rarefaction of the air explains very well the difficulty and
trouble in breathing, but it does not explain the panting and the
extreme prostration which the slightest movement causes.
To explain this new element, Brachet, who has just fallen into
so strange an error in physics, expresses the most suitable ideas:
The panting (he says) results from the darker blood which
reaches the lungs and does not find, in the rarified air which enters
there, a sufficient quantity of oxygen to revitalize it quickly enough.
The lassitude results from the fact that the blood, which is therefore
not well aerated, no longer gives the muscles the normal stimulus
which they need to contract.
This view, which is so simple, so clear, and, let us add in ad-
vance, so true, did not end the controversy, however.
In fact, a few months afterwards, Castel,G7 a member of the
Academy of Medicine, discussing the question theoretically, ex-
presses himself on the subject in the vaguest terms; no doubt, for
him, the physiological phenomena observed on lofty mountains are
due to the decrease of atmospheric pressure, but, he adds:
Not that this pressure is, as certain authors have maintained, the
immediate agent in the movement of the blood in the most remote
arterial ramifications and the veins, but it exerts a direct and constant
influence upon contractility, of which the flow of animal liquids is
never independent. The contractility is checked to a degree propor-
tional to the amount of decrease of atmospheric pressure.
Finally, in this same year, the celebrated German physiologist
Vierordt os made a certain number of experiments upon the effect
236 Historical
of slightly expanded air upon respiration. He gives no informa-
tion about the manner in which he carried on his experiments,
which dealt only with pressures included between 340 and 330 lines
of Paris (767 and 744 mm.) .
Their chief purpose was to find out whether variations in pres-
sure have an effect on the exhalation of carbonic acid; their results
are not very clear, in spite of the profusion of tabelles in which
they are expressed and the wealth of decimals of doubtful deriva-
tion which accompany each number. All conclusions based on these
experiments would seem to me extremely rash. Besides, the slight
barometric oscillations within the limits of which they are kept
prevent them from having any interest for us.
It was also at this same period that M. Lepileur's C9 memoir
appeared, the interesting narrative of which we have quoted in the
proper place and in considerable detail (See page 98 et seq.). This
work is not only rich in precise and shrewd observations, but it also
contains theoretical views, the importance of which deserves our
full attention. M. Lepileur first gives credit to the explanations of
de Saussure and those of Brachet; but they do not satisfy him:
The phenomena relating to hematosis do not seem to us the only
causes of the panting and lassitude on lofty mountains ....
One gradually becomes used to the rarefied air so that he no
longer feels its effect. If it depended only on the more or less com-
plete stimulation of the muscles by a blood which is more or less
arterial, would this fatigue be accompanied by pains of back and
limbs, and would it be likely to disappear thus through habit in so
short a time?
We should be tempted to consider this painful fatigue as resulting
chiefly from the congestion of blood taking place in the muscles during
their action, in proportion to their efforts, and the whole group of
phenomena due to the rarefaction of the air seems to us to agree fairly
well with this idea. The more active the circulation is, the more easily
congested the organs are. Now the pulse, without losing strength,
becomes considerably more rapid when one is ascending a mountain,
and the tendency to congestions is completely demonstrated by the
facts which we have given .... When one remains motionless, equi-
librium is maintained .... but as soon as one begins to move, the
contracted limbs become the seat of a congestion which occurs with
a rapidity proportional to the increase in the speed of the circulation.
(P. 62-64 of the separate printing.)
Beside the congestion of blood in the muscles, which, according
to him, explains the lassitude, M. Lepileur places exertion, which
would explain the nausea, the impending syncope, and the head-
ache:
Theories and Experiments 237
During exertion, there is a stasis of blood in the capillaries and
congestion in the brain, the lungs, and the muscles. When one makes
a series of almost uninterrupted efforts, .... when one runs up a
stairway, .... vision is dimmed, vertigo occurs, a painful fatigue is
felt in the limbs, and muscular strength fails. But if one stops to get
his breath before the effects of the cerebral and pulmonary congestion
have reached this point, the blood then flows back towards the heart,
the face grows pale, and a well denned sensation of fainting is felt;
sometimes the syncope occurs even when one has not taken care to
place himself immediately in a horizontal position ....
If now we consider the phenomena observed in the organism at
great heights, we find exactly the same course and the same signs.
Except that the rarefaction of the air, by making respiration more
frequent and the panting more rapid, necessarily hastens the rest of
the ordinary effects of exertion ....
The slight hemorrhages of the gums, the imminence of hemoptysis,
and the epistaxis are explained by the congestion, as a result of
exertion ....
As to the distress in the stomach, must we not consider the grad-
ual expansion of the intestinal gases under a constantly decreasing
pressure of the atmosphere as contributing greatly to this phenomenon
and to those which accompany it? ... . And yet we have not observed
any increase in the volume of the abdomen. (P. 65-68.)
We see that M. Lepileur considers that everything is explained
by congestions of the muscles and the nervous centers, due to
exertion and increased by the panting, about the cause of which
he says absolutely nothing.
It appeared very difficult, after so complete and detailed an
observation, to deny the harmful effect of altitude under certain
circumstances. And so, following the account of his ascent of the
Wetterhorn (3707 meters), on August 31, 1845, A. Vogt 70 protests
against denials which are at least unwise; moreover, he tries to
explain them, but he is not very successful in this attempt:
We see (he says) in the narratives of travellers who have climbed
lofty mountains strange contradictions; some mention frequent and
more or less serious disturbances, others deny them completely. It
seems to me that three factors act upon the human organism at great
altitudes:
1) The decrease of weight of the atmosphere and the consequent
expansion of the air; 2) the dryness of the air; and 3) the light
reflected from the stretches of snow.
Martins, Barry, Agassiz, Desor, Escher von der Linth, etc., who
felt no symptoms, blame the imagination of their predecessors. I can
contradict them on one point. During the night which we passed at
the Aaresattel, I was astonished at the rapidity of my breathing; my
respiratory rate was twice as great as on the plain, although I did not
feel the slightest discomfort.
238 Historical
It is natural for one to breathe more air in a rarefied atmosphere,
in order to bring the same quantity of oxygen to the blood, since in a
given volume of air there is less weight of it than on the plain. If
there are many mountain climbers who have not noticed this phe-
nomenon, that is because the diminished atmospheric pressure is a great
help in the expansion of the thoracic cavity, and thereby makes
respiration easier.
Father Hue 71 is not a skeptic, far from it. His well-known
credulity even robs his accounts of much authority. Nothing is so
strange as this simplicity which very lightly borrows the language
and the aid of science. In fact, he adopts absolutely the idea of
poisonous emanations or vapors; but, more daring than his prede-
cessors, he even specifies the nature of them, and considers that they
are formed of carbonic acid:
The mountain Bourhan-Bota has this very strange peculiarity,
that the harmful gas exists only on the part that faces east and north;
on the other side, the air is pure and quite respirable; it seems that
these poisonous vapors are nothing but carbonic acid gas. The people
attached to the embassy told us that when it was windy, the vapors
were hardly noticeable, but that they were very dangerous when the
weather was calm and serene. Since carbonic acid gas is known to
be heavier than atmospheric air, it must condense on the surface of
the ground and remain there until a great agitation of the air sets it
in motion, scatters it through the atmosphere, and neutralizes its
effects. When we crossed Bourhan-Bota, the weather was quite calm.
We noticed that when we were lying down on the ground, we breathed
with much more difficulty; if, on the contrary, we mounted our horses,
the influence of the gas was hardly felt. Because of the presence of
carbonic acid, it was very difficult to light a fire, the argals burned
without flame, shedding much smoke. However, it is impossible for
us to tell how this gas was formed and whence it came ....
A terrible quantity of snow fell during the night; those who, on
the day before, had not dared to keep on, joined us in the course of
the morning; they told us that they had finished the ascent of the
mountain with ease because the snow had dispelled the vapors.
(P. 265.)
These regions, so rarely explored, were crossed in 1873 by Cap-
tain Przevalski.72 He rejects absolutely the explanation which we
have just reported:
The great elevation of northern Thibet causes marked difficulty
in breathing, especially if one walks quickly; then come vertigo,
trembling in the legs, and even vomiting. The fuel of the country
(argal) is hard to burn because of the rarefaction of the air and
the rarity of the oxygen.
The missionary Hue explains the same phenomena, which he
observed on the mountain of Burchan-buda, by emanations of carbonic
Theories and Experiments 239
gas; but that is a mistake, for many Mongols from Tsaidam remain
there during the summer with their cattle, which would not be pos-
sible if asphyxiating gases escaped there .... Father Hue should not
be believed when he speaks of the harmful gases of Burchan-buda.
(P. 174.)
Dr. Pravaz,73 a physician of Lyons, a few years before, had
founded an establishment in which he used a stay in compressed
air for the treatment of different diseases. The book which he
devoted in 1850 to the exposition of the data which he had ob-
served contains, in its first part, interesting remarks on the different
causes of mountain sickness:
1. Respiration is mechanically restrained in its extent by the lack
of elasticity of the atmosphere, which presses upon the interior of the
lungs and by itself causes their development when the thorax expands
through the effort of the inspirating muscles.
2. This function is insufficient for hematosis, because the oxygen,
or the vivifying principle of the blood, is present in too small an
absolute quantity in the volume of air introduced by each movement
of the inspiration, in addition to the fact that the lack of pressure
makes the quantity of this gas dissolved in the blood less abundant.
3. The arterial circulation is accelerated as a result of the rapidity
of the respiratory movements caused by the instinct of self-preserva-
tion, while the capillary circulation slackens, because the recall of the
venous blood to the right cavities of the heart has become less ener-
getic on account of the decrease of the constriction exerted on the
periphery of the organs. (P. 57.)
Farther on, while discussing at length these congestions of the
mucous membranes which have attracted so much attention from
the observers, he explains them by saying:
One of the motors of the venous circulation, and consequently of
the capillary circulation, namely, the atmospheric pressure, decreases
as one rises above sea level. The greater the altitude, the less active
will the recall of the blood into the right cavities of the heart be,
and the greater tendency will the blood have to congest the parts
where aspiration is ordinarily most effective. We may then compare
the action of the heart with that of a pump working in a medium
where the air is very much rarefied, and which can draw water only
at a depth much less than under the ordinary pressure of the atmos-
phere ....
Hence the tendency to hemorrhages and apoplexy on lofty moun-
tains.
Mountain sickness presents another symptom which no one has
tried to explain physiologically. It is evidently produced by a disturb-
ance of the circulation in the portal vein system; it is characterized,
in fact, like congestions of the liver and the abdominal viscera, by
vomiting, cramps in the stomach, and intestinal pains. (P. 82.)
240 Historical
As to the differences presented by different individuals with
reference to the altitude at which mountain sickness attacks them,
Pravaz finds reason for that in the inequality of "the resistance of
their tissues and in the vital contractility of their lungs". The
sudden appearance of symptoms, a suddenness which our
author exaggerates, is due to the fact that "in an almost indi-
visible moment, the atmospheric pressure becomes less than the
reaction of the lung, and ceases to be able to struggle successfully
against it. . . . The decrease of the quantity of oxygen contained
in the air breathed would not be great enough to explain this fact,
for this decrease . . . could bring on dyspnea only gradually".
(P. 76.)
Be that as it may in regard to this last restriction, up to that
time the alternative explanation given by de Saussure had been
accepted without dispute, an explanation which tends to attribute
the discomforts of decompression chiefly to the insufficient quan-
tity of oxygen which the respiratory acts bring into the lungs. But
in 1851, Pay erne,74 an engineer who gave much attention to diving-
bells, raised an objection to this hypothesis, the worth of which
we shall discuss later:
Upon the highest summits ever ascended, the pressure is equal at
least to 32 cm. of mercury. The air there contains still 125 gm. of
oxygen per cubic meter, or 100 gm. per 800 liters which a man-
breathes per hour. Now experiments, the accuracy of which no one
could question, have recently shown that a man while resting con-
verts only 50 gm. of oxygen into carbonic acid. Assuming that while
at work he would convert 5 and even 10 gm. more, he will be far
from lacking it in a place where the barometer stands at 32 centi-
meters ....
The weariness and the panting in lofty places therefore do not
seem to me to come from an insufficiency of oxygen, but from the
rupture of the equilibrium between the tension of the fluids contained
in our organs and that of the ambient air, no matter in which direc-
tion the rupture operates.
The authors who followed Payerne seemed not to have known
of his objections. Marchal de Calvi,75 among others, reproduces
purely and simply the former explanation; this is shown by the
extract from his work, published by the Proceedings; this extract
we quote in full:
The author thinks that he can conclude from the experiments
reported in this Note that the variations in the atmospheric pressure
are far from exerting the influence attributed to them. According to
him, the mistake comes from the fact that in most cases which have
been considered, when there is a decrease in pressure on the surface
Theories and Experiments 241
of the body, there is at the same time rarefaction of the air entering
our lungs, and consequently decrease in the quantity of oxygen nec-
essary for the normal accomplishment of hematosis.
In 1853, Speer,76 an English physician, published a special work
on the nature and causes of mountain sickness. He begins by tell-
ing that he himself, on the main peak of Mont Blanc, began to feel
the following symptoms when he had reached 9000 feet:
Congestion in the head, throbbing of the carotids, palpitations of
the heart, distaste for food. At 10,000 feet, he felt a constriction of the
chest, and shortly after, the taste of blood in his mouth, which was
caused by a slight exudation from the gums.
He then reviews the different explanations suggested, dwelling
on that of Brachet, which he finds "too exclusive". To his mind,
the great fatigue of the muscles is caused by "the congestion of
blood which follows their repeated contractions", and as for the
other symptoms of mountain sickness, they are due chiefly to "the
irregularity of the circulation, with congestion of the brain and
the abdominal viscera".
The following conclusions indicate clearly the author's line of
thought:
Mountain sickness is characterized by the following symptoms,
the union of all of which, however, is only rarely seen, if ever, in
the same person: vertigo, headache, drowsiness, dyspnea, constriction
of the chest, palpitations, tendency to syncope, oozing of blood from
the mucous surfaces, increased rapidity of the pulse, anorexia, nausea
and vomiting, thirst, feverish tongue, muscular pains, sensation of
extreme weakness in the lower limbs, general prostration.
These symptoms should be attributed to three causes: gradually
increasing congestion of the deep portions of the circulatory apparatus;
increase of venous plethora of the blood; loss of equilibrium between
. the outer air and that of the gases present in the intestine.
These determining causes of mountain sickness are themselves the
result of the considerable and rapid change in the pressure and the
temperature of the atmosphere.
The next year, Dr. Conrad Meyer-Ahrens," a physician at
Zurich, devoted to the study of the symptoms of decompression
a long work far more important than that of Speer.
This memoir is composed of two parts; in the first (p. 1-99)
the narratives of a great many travellers are reported with details;
the second summarizes the symptomatology (p. 99-123) and indi-
cates the etiology (p. 123-136), the prophylaxis and treatment (p.
136-139) of mountain sickness.
In the preceding chapters, we have given all the data quoted
242 Historical
by Meyer-Ahrens and many others besides; since this part of his
work contains no personal observation, I shall not speak of it. But
from the part devoted to symptomatology, I extract a very good
summary of the symptoms from which mountain travellers have
suffered in different degrees:
The principal symptoms or at least those which occur oftenest in
man are: discomfort, distaste for food, especially distaste for wine
(however, the contrary has sometimes been noted), intense thirst
(especially for water, which quenches the thirst best), nausea, vomit-
ing; accelerated and panting respiration; dyspnea, acceleration of the
pulse, throbbing of the large arteries and the temples; violent palpi-
tations, oppression, anxiety, asphyxia; vertigo, headache, tendency to
syncope; unconquerable desire for sleep, though the sleep does not
refresh but is disturbed by anguish; finally, astonishing and very
strange muscular fatigue. These symptoms do not always appear all
together .... Others are observed, although less frequently, such as
pulmonary, renal, and intestinal hemorrhages (in animals also);
vomiting of blood; oozing of blood from the mucous membrane of the
lips and the skin (due merely to the desiccation of these mem-
branes), blunting of sensory perceptions and the intelligence, impa-
tience, irritability, .... finally, buzzing in the ears. (Pages 100-101.)
But the chapter most interesting to us is that on etiology. I
quote here the principal passages:
All that we have just said about the etiology of mountain sickness
shows: 1) that it appears at varying altitudes; 2) that meteor-
ological conditions, temporary or general personal characteristics, and
the speed of walking vary the altitude at which one is attacked and
the severity and number of the symptoms.
When one sees the appearance of mountain sickness correspond
to varying altitudes, he asks himself what circumstances depending
upon the altitude are capable of causing the phenomena which con-
stitute it. In my opinion, the principal role belongs to the decrease of
the absolute quantity of oxygen in the rarefied air, the rapidity of
evaporation, and the intense action of light, direct or reflected from
the snow, whereas the direct action of the decrease of pressure should
be placed in the second rank. I find the immediate causes of mountain
sickness in the changes made in the composition and the formation
of the blood by the decrease in oxygen and the exaggerated evapora-
tion, changes to which are added others due to the action of light
on the cerebral functions, an action which affects the preparation of
the blood liquid.
These suppositions permit us to include — if we also take into
account individual constitutions — all the phenomena of mountain sick-
ness, without needing to appeal to the -direct action of the decrease
in the weight of the air. This explains the acceleration of the respira-
tory movements and the circulation, the congestions, the hemorrhages,
the functional disturbances of the brain and the extraordinary fatigue
of which almost all travellers complain. "We see too why mountain
Theories and Experiments 243
sickness attacks not only travellers on foot, but also horsemen; why
the former are stricken much more severely (twice as severely, ac-
cording to Tschudi); why exertion aggravates it; why it disappears
when the traveller stops walking for a moment and reappears imme-
diately when he starts again; why, however, just as horsemen
themselves feel its painful symptoms, so at very great heights rest
does not completely free travellers from it (de Saussure, A. Vogt) ;
why walking on a level at great heights is often accompanied by
distress which increases when one walks more quickly or begins to
climb; why aeronauts are not exempt from disturbances of respiration
and circulation; why patients stricken by the disease of the Puna are
advised to sit quietly in rooms which are warm and well closed, etc.
(Pages 131-133.) ....
Other phenomena can in part be attributed to the immediate
action of the diminished pressure, as, for example, the strange sensa-
tion of lightness of which many travellers speak, the violent beating
of the heart, qualms, nausea, vomiting, and oppression. In fact, the
lessened pressure of the air, by lowering resistances, aids rapid walk-
ing, respiratory movements, and the action of the heart, while at the
same time it tends to increase the volume of gases contained in the
intestinal canal; so that distention of the stomach and the crowding
upward of the diaphragm may bring on nausea and oppression. But
these phenomena of direct action may be relegated to the second
rank, as I have already said. (P. 134.)
We know, from the experiments of the Webers, that the great
lassitude of mountain travellers is due to a direct action of the
diminished atmospheric pressure; but we must understand that not
only the large muscles, those that move the large bones and hold
them in their articulations, become weary, but the same thing is also
true of the small muscles, like those of the tongue and the larynx
(Parrot and Hamel) ; a phenomenon which must be general and keep
increasing, as A. Vogt asserts, if it is the consequence of the decrease
in pressure, and that really does happen. Here too, we must make
allowance for individual peculiarities. (P. 135.)
So, in the eyes of Meyer-Ahrens, the immediate causes of
mountain sickness are, in the first place, the decrease in the abso-
lute quantity of oxygen in the rarefied air; then come the rapidity
of evaporation, the intense action of the light, the increase in vol-
ume of the intestinal gases, and a weakening of the coxo-femoral
articulation.
Dr. Lombard,TS who almost at the same time wrote for the
Bibliotheque de Geneve excellent articles which he soon afterwards
collected and published in a brochure, returns purely and simply
to the two old explanations of de Saussure: diminution of weight
sustained, diminution of the quantity of oxygen contained in the
same volume of air; then the theory of the Webers appears again:
244 Historical
There is a very important element in mountain climates; it is a
lessened atmospheric pressure and consequently an air which is less
dense, as well as a decrease in the quantity of oxygen which is
necessary to maintain life by means of respiration. To these last two
circumstances are due in great part the phenomena observed on lofty
mountains, and to these two I wish to call the attention of my readers
for a few moments.
If we question physics, we shall see that the total weight of the
atmosphere represents as many times one hundred three kilograms
as there are square decimeters on the surface of our body, so that,
depending upon the height of different persons, the total weight sus-
tained by our organs will vary between fifteen and twenty thousand
kilograms. If then we leave a country more or less near sea level for
a higher elevation, our bodies will sustain a pressure which will
diminish in proportion to the increase in altitude. We can understand
what a shock it must be to our organs when the enormous weight
to which they are usually subjected is diminished by a sixth, a quar-
ter, and even a third, as is noted on the Righi, the Saint Bernard, or
the summit of Mont Blanc. And if we add to this decrease in pressure
the no less important change which takes place in the density of the
air, and consequently in the quantity of oxygen, we shall not find it
difficult to explain the various disturbances which occur in the respi-
ration, the circulation, the locomotion, and the digestive processes
of those who climb the lofty peaks of our Alps, or dwell there for a
time.
In the appearance of the symptoms of which we are speaking,
what part is played by a low pressure, and what part by an insufficient
quantity of oxygen? That question is hard to answer, since both
respiration and circulation should be equally modified under these
two influences and should react on the muscular strength; on the
other hand, now that recent researches have shown that the head of
the femur is kept in the cotyloid cavity by means of the atmospheric
pressure, it is clear that a decrease in the weight of the air should
make movements more difficult; so that we reach the conclusion that
the phenomena produced in living bodies, transported to great heights,
are the result of the two meteorological conditions of which we have
just spoken: a decreased pressure and a smaller quantity of oxygen.
(P. 273.)
But shortly after this, M. Giraud-Teulon, a French physician
who was very competent in matters relating to physics, completely
exposed the fundamental error upon which M. Lombard, along
with so many others, was relying.
Long before this, Valentin,71' calculating the amount of the
changes in the weight of the atmosphere on the surface of the
human body at different heights above sea level, and admitting
that organic matters are compressible to the same degree as water,
had shown that:
Theories and Experiments 245
For one atmosphere of added pressure, the decrease of volume
would be about 0.2 of a cubic inch, that is, 1/22522 of the total volume
of the body.
We see then that the volume of a man who was on the summit
of Mont Blanc and let himself slide down would contract only seven
one-hundred-thousandths. (Vol. I, p. 84.)
However, this clear demonstration of the lack of importance of
changes in pressure considered from the mechanical point of view
had not kept a very eminent author, Heusinger,80 from repeating
with many details the explanation carelessly approved by so many
travellers:
The pressure of the atmosphere upon the body diminishes .... At
sea level, it has been calculated that an adult man would sustain a
pressure equal to 33,893 pounds; if he ascends to the height of Mont
Blanc, the pressure will be only 19,334 pounds .... The bones will
no longer be held in their articulations with the same strength, the
muscles will have to exert greater force, fatigue therefore will be
greater, .... the blood will be held with less force in the vessels, it
will have a tendency to transude and to form hemorrhages where
the walls are thin enough, and the blood will accumulate in the less
contractible organs, where the capillary vessels can be expanded more
easily, for example, in the mucous membrances, the lungs, and the
brain; there will be congestion in these organs; the heart, which has
fewer obstacles to overcome, will contract more often and the pulse
will become more frequent. (Vol. I, p. 252.)
We must note that to this erroneous cause a number of others
are added, which are more or less justified, according to the
vagaries of the eclectic method. First come evaporation due to
decreased pressure and dryness, lower temperature, the action of
the rays of the sun, which is stronger and "penetrates the body
more deeply, and irritates the eyes, the brain, and the spinal cord",
then electricity, "probably stronger and less often negative", and
finally the lessened quantity of oxygen in the rarefied air, which
"counterbalances the frequency of the respiration and the circu-
lation".
To return to the mechanical explanation, it was absolutely
demolished by the work of M. Giraud-Teulon, and we are surprised
that after such a thorough refutation, it has appeared again in
books and even in the academies.
M. Giraud-Teulon S1 first lays down two principles which have
been too much forgotten by physicians and physiologists, before
and after him:
246 Historical
1. All pressures exerted by the ambient atmosphere upon the
human body naturally oppose each other and balance each other
perfectly.
2. The force exerted by the weight of the atmosphere is, more-
over, counterbalanced by the incompressibility of the liquids with
which all our organs are imbued, and by the tension of the gases and
vapors in the splanchnic cavities and interstices. Thus the skin is
placed between two forces which strive in opposite directions and
cause an equilibrium.
Then he asks himself:
Whence comes the difference (a difference, the nature of which
he unfortunately does not explain) observed between the corpse and
the living body in the reaction of the two to outer pressure? Should
we attribute it entirely to the difference in temperatures? But the
temperature of the human body is not high enough to give a tension
of more than 3 or 4 centimeters of mercury to the vapors of the
liquids which it contains. Should it be attributed to the gases dis-
solved in these liquids? But the experiments of Magnus prove that
if their quantity, merely for some of them, reaches proportions suffi-
cient to carry the tension of the liquids containing them to a figure
which equals or surpasses the atmospheric pressure, their action and
their reaction, with reference to the atmosphere, would be purely
physical. Now Magnus has shown, on the contrary, that the gases
dissolved in the blood are retained there by quite other forces than
simple pressure. For it is not enough to raise the temperature or to
lower the outer tension, even to just a few centimeters, to expel the
gases dissolved in the liquids of the body; it requires the presence of
other gases for which the blood has a greater affinity than for the
normal gases which it contains. Where then shall we find the inner
force which balances the ambient pressure? In the study of the laws
of circulation and pressure in the great vascular systems.
The author then shows that, in the living animal, because of
the circulation of the blood, the tissues are always in a state of
tension which he estimates at from 8 to 15 millimeters of mercury.
Since this tension is constant, the result is, he says:
That the organic system of the living being is never endangered
by even a great variation, if it is gradual, of the outer pressure and
that the circulation would continue as it was before the variation.
And this explains the data collected by M. Poiseuille and by M. Tingu,
in regard to the continuation of the vital functions, in spite of a
considerable increase of the ambient pressure.
The dangerous power of the gases of the blood, freed by the
decrease of pressure, a hypothesis which Robert Boyle was the
first to express and which M. Giraud-Teulon strongly opposed, as
we have just seen, found an able defender in Felix Hoppe.82 The
work of this chemist is of a purely experimental type; it was
Theories and Experiments 247
undertaken with the purpose of explaining the symptoms which
attack laborers working in compressed air; and as everyone has
observed that these symptoms occur at the moment of decom-
pression, Hoppe hoped to find their cause by studying death in
rarefied air. Here first is the summary of his experiments:
A rat was subjected to a rapid decrease of pressure. Convulsions
occurred at about 50 mm. of mercury .... and death between 40
and 50 mm. On opening the thorax, .... there could be seen through
the walls of the vena cava, and the right auricle and ventricle, a
considerable quantity of gas which could be released by puncture ....
In a cat ... . which died at about 40 mm., .... I found about
0.3 cubic centimeters of air in the vena cava and the right cavities
of the heart; there were a few bubbles of air in the left auricle. The
veins and the right heart were full of blood, the left heart almost
empty; the blood was completely liquid, the arteries contracted
spontaneously, the ventricles only under stimulation; the lungs were
empty of air and healthy; there was no rupture of vessels; the brain
was normal ....
Two swallows died .... at a pressure between 125 and 120 mm.;
I found a few small bubbles of air in their blood
In birds as in mammals, the blood of the left heart was bright
red, and consequently still contained oxygen ....
Two frogs taken to the point of complete collapse were opened;
there was no gas in their hearts .... A slow-worm taken to a
pressure of 22 mm. swelled and remained motionless; then, a few
minutes after being returned to normal pressure, it seemed as well
as before.
Summarizing:
1. Birds die long before the point of effervescence of their blood;
mammals die at a pressure hardly above this point; amphibians do
not die even below this point;
2. In warm-blooded animals, gas escapes in the interior of the
vessels as a result of rapid decrease of pressure. This is not true of
amphibians.
F. Hoppe then asks himself whether death should be attributed
to this escape of the gases of the blood, or to the lack of oxygen
in the blood. It is very difficult to answer this question, he says:
"For, in the autopsy, the arterial blood is still bright red, and
very different from the blood of animals dying of asphyxia" (P.
67) ; an observation which is accurate, but due to an experimental
error which we shall demonstrate later. At any rate, the sudden
death seems to him to be certainly due to the obstruction of the
vessel by the gases liberated:
The heart exerts upon its contents a pressure of 100 mm.; if the
air in the large venous trunks has a pressure of only 50 mm., it must
248 Historical
be compressed a third of its volume to enter the arteries; the result is
a great slackening of the circulation. If this slackening, joined to
the small quantity of oxygen contained in the blood and the unequal
power of the right and the left heart, can cause death, it can be only
an instantaneous death. This death can be caused only by the
obstruction of the capillaries of the lungs by bubbles of air, whence
comes the stoppage of the circulation.
He does not limit himself to this theoretical demonstration, and
tries to prove experimentally that it is not the lack of oxygen, But
the decrease of the pressure which kills animals placed under the
bell jar of the pneumatic machine. To make this proof, he uses a
method which, long before I knew the work of Hoppe, one of the
last I found in my bibliographical research, I frequently used, and
from which, as will be seen, I have drawn conclusions diametri-
cally opposite to his. It will be interesting to discuss the reason
for these differences; but this is not the place to do so.
At any rate, Hoppe said to himself: if it is the decrease of pres-
sure which brings death, and not the lack of oxygen, death will
necessarily occur at the same pressure, even if pure oxygen is
used:
A guinea pig fell in convulsions at 77 mm.; pure oxygen was
admitted into the b'ell, and it rose at once. When the pressure had
been lowered again, it experienced the same symptoms at 75 mm.; sec-
ond admission of oxygen, third lowering of pressure: symptoms at 75
mm.; another admission of oxygen, collapse at 75 mm. Return to
normal pressure; the animal survived. (P. 69.) ....
So the symptoms of sudden asphyxia came at the same pressure,
whether the animal was in air or in oxygen.
From this he draws the definite conclusion that the cause of
death lies in the appearance of free gases; the moment of their
escape varies with "the pressure, the temperature of the animal,
the power of absorption and the affinity of the blood for gases, and
the quantity of blood corpuscles".
The important researches of M. Fernet 83 this same year brought
to the question a new element which, during later discussions of
the cause of mountain sickness, seemed to support mistaken
theories.
Ever since the early experiments of Robert Bojde, it had been
known that gases in considerable quantities are present in the
blood. More recent chemists, particularly Magnus81 in 1837, had
shown that oxygen forms a very large proportion of the gases.
From these experiments physiologists had been led to conclude
that respiration is only a simple exchange of gases between the
Theories and Experiments 249
carbonic acid of the blood and the oxygen of the air, an exchange
regulated by the laws of physics. 85.
The work of M. Fernet made them change their minds. This
physicist, by a series of experiments carried on with unusual
shrewdness, showed that carbonic acid and oxygen are kept in the
blood chiefly by a chemical affinity. The method of demonstration
which he used is directly connected with our subject, since he
utilized the effect of changes in the barometric pressure.
The method used by M. Fernet involved removing from the
blood the gases which it contained, agitating it in closed vessels,
with oxygen or carbonic acid under various pressures, and meas-
uring the quantity of gas which it absorbed under these different
conditions.
He thus showed that:
The volumes of oxygen chemically absorbed and independent of
the pressure have a relative value so great that these experiments
are immediately distinguished thereby from those which relate to
saline solutions and even to serum. Not only is the progress of the
phenomenon almost completely freed from the law of simple solution,
but the volumes absorbed seem from the very first to be independent
of the pressure, since the volume, when chemically combined, is
almost five times as great as the volume when dissolved under atmos-
pheric pressure. (P. 209.) ....
In respiration, the oxygen of the air exerts a pressure which
amounts to only one-fifth of the pressure of the atmosphere, so the
volume dissolved in the blood of the respiratory apparatus must be
reduced in the same proportion. The volume of oxygen absorbed in
the state of combination by the corpuscles will then become about
twenty-five times as great as the volume which actually enters the
serum in the state of true solution. (P. 211.)
From this well established fact, in his actual experimental
conditions, M. Fernet thought he could draw the following con-
clusion:
This is the explanation of this result, already verified by a great
many observations, that the absorption of oxygen is practically the
same, on the summits of mountain and on the plains, whatever the
atmospheric pressure; however, observation, here agreeing with
theory, has already noted slight differences corresponding to differ-
ences in pressure; but they can be demonstrated only by measuring
methods capable of great accuracy. (P. 211.)
We should make reservations about this conclusion, which does
not seem to us to be included in the experimental premises. But
we shall see that certain physiologists let themselves be drawn
far beyond that. In this number is Longet.
250 Historical
Longet SG rapidly reviews the observations of mountain trav-
ellers and aeronauts; he lists the different explanations which they
have given of the symptoms felt. He agrees that sudden changes
in the pressure can decrease the oxygenation of the blood, because:
A certain lapse of time is always necessary for the equilibrium
between the gases of the blood and the outer gases to be completely
established, and also for the more active movements of respiration to
be put in harmony with the new conditions, so that the lungs absorb,
in a given time, almost the same quantity of oxygen as the normal
state requires. (First edition, p. 474; third edition, p. 560.)
But if one stays a long time, a complete equilibrium is estab-
lished. In fact, he says:
If, at each breath, the mountain dweller necessarily draws less
oxygen into his lungs than the plain dweller does, he compensates
for that by more frequent inspirations, so that, after all, in both of
them the same quantity of oxygen can be absorbed in the same time.
(First edition, p. 475; third edition, p. 561.)
And farther on, speaking of the oxygen of the blood, he writes
this quite explicit passage:
We know that the quantity in weight of a gas dissolved in water
is always proportional to the outer pressure; applying this law to the
case in question, we would reach this conclusion that the blood of
dwellers in regions where the atmospheric pressure is hardly 0.380
meters would contain one-half less oxygen than the blood of dwellers
by the seashore, where this pressure is 0.760 meters; but no doubt
the preceding law does not apply here, because some chemical affin-
ity interferes. (Third edition, p. 592; first edition, p. 493.)
That was also the opinion of M. Gavarret,ST who, in 1855,
expressed himself as follows:
It would be false to say that the absorption of oxygen by venous
blood is a purely physical fact; everything proves, on the contrary,
that chemical forces play an important part in this fixation of oxygen.
If, in fact, its absorption was a simple physical solution, while the
outer pressure remained the same, the quantity of oxygen absorbed
should increase in direct ratio to the proportion of this gas in the air
breathed by the animal; now the experiments of Lavoisier had already
shown and those of M. Regnault had proved indisputably, that how-
ever great is its proportion in the artificial atmospheres created
around the animals, the consumption of oxygen remains the same.
In the second place, if the composition of the air remains the same,
the ponderable quantity of oxygen dissolved physically by a liquid
varies proportionately to the outer pressure. In the hypothesis that
the phenomenon took place entirely through physical forces, the
mass of oxygen absorbed by the residents of cities situated on the
Theories and Experiments 251
lofty plateaux of the New World would necessarily be reduced to very
small proportions; the animals which live permanently at the dairy
farm of Antisana, where the barometer stands at only 47 centimeters,
would absorb a weight of oxygen less than two-thirds as much as
they consume at sea level. Such a variation in so important a
function would certainly cause great changes in their mode of exist-
ence, which surely would not have escaped observation. If the
oxygenation of the blood in the pulmonary capillaries was a purely
physical fact, in birds of lofty flight which pass instantly from the
surface of the earth to the highest regions of the atmosphere, the
consumption of oxygen would undergo variations too sudden and too
extensive not to endanger seriously the lives of these animals. (P. 262.)
Moreover, in 1868, in his third edition, Longet borrowed this last
objection from M. Gavarret, and added to the passage which I
quoted above the following remark:
How can we admit that observers would not have been struck
by the profound changes which such variations would not fail to
produce in the mode of existence of these populations?
After that, is it not strange to see that when M. Jourdanet, as
an "observer", noted "these variations in the mode of existence
of the populations of lofty places", his conclusions were rejected
by an exception drawn from the fact that by virtue of chemical
laws oxygen cannot be removed from the blood by decrease of
pressure?
In 1858 there appeared the second edition of the book of M.
Lombard,88 of which we have already spoken; in announcing it,
the editor of the Bibliothcque XJniverselle, Dr. Duval, 89 expresses
himself in these characteristic terms:
The researches on mountain sickness have been completed and
better coordinated; perhaps the author made the possible symptoms
of the digestive functions at an altitude of 1300 to 2000 meters seem
a little too common. Many tourists will state that at that height they
feel neither lack of appetite, nor nausea, nor vomiting, but on the
contrary, an excellent and hearty appetite; some will also deny this
distaste for wine and alcoholic liquors which would be experienced
under the same circumstances; but that is only a question of a few
meters more or less, and the reality of the symptoms described is
none the less constant at an elevation which varies with the indi-
vidual. De Saussure, who did not begin to be perceptibly affected
until he had reached a height of 3800 meters, may pass as an
exception.
As for M. Lombard, he thinks much less of the direct effect of
the diminished weight of the air; he also brings up the objection of
Payerne, but none the less he gives great importance to the les-
252 Historical
sened quantity of oxygen contained in expanded air, of equal
volume:
MM. Barral and Bixio, .... in spite of the fact that more than
9000 kilos were taken from the pressure to which their bodies were
accustomed, felt no very pronounced sensation .... On the other
hand, workmen in diving bells endure a double, triple, or even
quadruple pressure without serious change in the functioning of the
organs; and by this we are naturally led to consider the differences
of atmospheric pressure as less important than one would be inclined
to think from the purely scientific point of view.
On the other hand, we have recognized that as one ascends
heights, the air becomes less dense and consequently contains less
oxygen, so that the respiration must be more frequent and more com-
plete to bring into the lungs the quantity necessary for the oxygenation
of the blood. From this physiological necessity there must result a
considerable difficulty in breathing and consequently in the circulation
also; and this we see in the dwellers in the lofty regions of our globe.
Yet we must not believe that the rarefied air of our mountains
does not contain a sufficient proportion of oxygen to maintain life;
experiments made on the quantity of oxygen necessary for respira-
tion have, in fact, shown that a man at rest in one hour converts 50
grams into carbonic acid, and if we add five or even ten grams for
the increase produced by movement or work, we shall see that,
assuming that the stay is in a place where the barometer stands at
only 315 mm. (7000 meters), the air still contains 100 grams of oxygen
in the 800 liters that a man breathes per hour. So that we see
definitely that, even at great heights, the atmosphere can furnish man
a sufficient quantity of oxygen to sustain breathing.
Does it follow, nevertheless, that this great decrease in an element
so essential to life has no effect upon our principal functions? We
do not think so, quite to the contrary; it is visibly evident that the
withdrawal of a considerable portion of oxygen must make respiration
incomplete and react upon the other vital functions which, like the
circulation, are very intimately associated with respiration.
But even that is not all; when an incompletely oxygenated blood
reaches the different organs, such as the brain and the muscular
system, it is evident that their functions will experience a disturbance
proportionate to the incompleteness of the oxygenation; so that one
must attribute to the decrease of oxygen a considerable portion of the
disturbances which occur in innervation and motility. (P. 47.)
M. Lombard then admits in part the explanation which the
Weber brothers had given and which von Humboldt had accepted
in regard to the role of the pressure on the cotyloid cavities.
Among the symptoms experienced by travellers attacked by
mountain sickness, the sensation of extreme cold is neither the
least strange nor the least painful. M. Ch. Martins,™ who had felt
it in his ascent of Mont Blanc in the company of Bravais and M.
Lepileur, made a special study of this physiological cold, an
Theories and Experiments 253
expression which indicates, in the mind of the learned professor
of Montpellier, not a drop in the body temperature, but the sen-
sation of cold which may be produced by various causes.
After studying these causes in a man at sea level, M. Martins
declares that others exist in the mountains. Some act indirectly
by changing the temperature of the air to which the sun gives less
heat as a result of its decreased density, and which receives very
little heat from the much reduced contact surfaces of the ground.
Let us add that its constant renewal does not give it time to
become warm, and that the expansion of ascending currents tends
to chill it. Other causes act directly upon the living body.
First is the power of radiation, which is twice as great on the
Grand-Plateau of Mont Blanc as at Chamounix; next, pulmonary
and cutaneous evaporation, stimulated by the low pressure, by the
wind which blows almost constantly in lofty regions, and by the
dryness of the air; finally, on lofty summits, the contact with a
frozen soil. These are the physical causes which tend to chill the
body. After explaining them in detail, M. Martins next comes to
the physiological causes of the chill, which are peculiar to high
mountains.
Here we quote verbatim:
Everyone knows that, at elevations which vary according to the
individual from 2000 to 4000 meters, one begins to feel painful sensa-
tions, namely: extreme panting accompanied by headache, desire to
sleep, nausea, and great lassitude. This is the phenomenon called
mountain sickness, a complex result of fatigue, abrupt decrease in
pressure, and especially the rarefaction of the air. Physiologists
consider that man draws into his lungs in an ordinary inspiration on
the average a half-liter of air; the oxygen of this half-liter of air
combines with the blood. At sea level, at a pressure of 760 mm. of
mercury, a half-liter of air weighs 0.65 gm. and contains in weight
0.16 gm. of oxygen; at a decreased pressure, 475 mm. for example, to
which we were subjected for three days at the Grand-Plateau, the
volume of air inspired is still the same; but its weight differs, for it
is reduced to 0.40 gm., and the oxygen contained by this half-liter
of air is only 0.10 gm., and on the summit of Mont Blanc, at a pressure
of 420 mm., only 0.09 gm
The oxygen of the blood and consequently the heat production
are therefore less than at sea level merely because the quantity of
oxygen drawn into the lungs is much smaller. Respiration is less
perfect, just as it is in foul air in which the proportion of oxygen is
lower than in normal air. This entirely physical cause had already
been pointed out by Halle, Lombard, and Pravaz junior. Like them,
I attribute to it the symptoms of panting which are noted in rapid
ascents on lofty mountains.
The objection that on lofty mountains the number of inspirations
254 Historical
compensates for the lessened proportion of oxygen in the air inspired
is not valid. Anyone who has himself experienced the short and hasty
inspirations, without proper expansion of the thorax, which accom-
pany the breathlessness during and immediately after an ascent,
realizes that these hasty inspirations cannot have the calorific effect
of regular inspirations. So panting ceases the moment one stops walk-
ing, and a regular respiration, more frequent than on the plain, partly
compensates for the lessened quantity of oxygen; I say partly, for to
make complete compensation, on the Grand-Plateau, for example, the
number of inspirations would be to the number on the plain as 8 is
to 5, that is, proportional to the quantities of oxygen inspired. Now
that is not the case; panting, in a state of rest, certainly does not add
one-third more. The lessened oxygenation of the blood is therefore
not counterbalanced by the frequency of the inspirations, and becomes
a physiological cause of cold which is peculiar to lofty regions, and
probably the principal one of all those causes which bring on the
symptoms known under the name of mountain sickness.
This explanation, we see, is only the one already envisioned by
de Saussure; we see also that M. Martins is much less optimistic
than Longet, who asserted that on the mountains one could make
up for the lessened oxygen content of the inspirations by their
number.
The same ideas also occur to the mind of Guilbert,!U when he
gives an account of the soroche of the Cordilleras:
Upon the plateau of the Cordilleras, the air contains only 3/5 of
the quantity of oxygen which it contains at 0.76. When one ascends,
he reaches colder and colder regions, where man must produce more
heat, to maintain his normal temperature. To expedite combustion,
he needs a greater quantity of oxygen, and the air contains less.
Here are two causes working in the same direction, which are suffi-
cient to explain the disturbance of the respiration and the circulation.
The experiments of Magnus have shown the presence of free
gases in the state of solution in the blood. The tension of these gases
increases as the pressure diminishes. Then these gases exert a
pressure against the walls of the vessels in which they circulate with
the blood, and distend them; hence come compression of the brain,
and consequently violent pains in the head, etc Perhaps too
hematosis is incomplete; in this case, it could claim part of the effect
on the nervous system; the blood, which has lost part of its stimulating
qualities, could no longer be a sufficient stimulus; hence the tendency
to syncope, etc
The decrease of the atmospheric pressure also explains the
hemorrhages. The free gases of the blood press against the walls of
the vessels; a moment may come when these walls, unable to resist,
longer, are ruptured and let the blood escape
The action of the heart is no longer counterbalanced by the
atmospheric pressure, and the result is a stasis of blood in the capil-
laries which are therefore distended. This phenomenon is evident
Theories and Experiments 255
in the face and the hands, and especially in the conjunctiva. The
same thing must take place in the capillaries of the lungs, and the
exaggerated contraction of the heart also has a share in causing the
difficulty in breathing.
Let us note, in addition, that Guilbert adopts the explanation
of the Weber brothers in regard to the connection between decom-
pression and the firmness of the articulation of the head of the
femur.
Finally I shall report the conclusions of Guilbert with reference
to pulmonary phthisis. This disease is very common on the Pacific
coast, except among the Indians. But in the Cordillera, according
to this physician, one observes:
1. The absence of phthisis among the natives, without any racial
distinction;
2. Curability by a prolonged sojourn, and in such a proportion
that this curability cannot be considered as the exception;
3. The constantly delaying effect of the climate upon the progress
of the disease in those who cannot be definitely cured, and the not
infrequent remissions.
In the year 1861 the first book of M. Jourdanet 92 appeared. This
work had a double merit; first, by actual observation, he recog-
nized certain signs of harmful effect from prolonged sojourn in
lofty places, although no one before him had suspected it; second,
by his explanation, he revived for science the idea glimpsed by
Pravaz, but rejected through the work of M. Fernet, of a lessened
solubility of the oxygen in the blood, in consequence of a dimin-
ished barometric pressure. The true doctrine is completely ex-
pressed in this volume. In the beginning, M. Jourdanet takes up
and develops the calculations of M. Martins:
The barometric pressure of Mexico is 585 mm. Consequently a
liter of air weighing, at sea level, 13 decigrams, weighs only about
1 gram in this capital. In both cases, oxygen figures in the proportion
of 23.01%. That gives us 299 milligrams as the weight of a liter of
oxygen at sea level, whereas this figure is reduced to 230 milligrams
for the altitude of Mexico.
Let us declare then a difference of 69 milligrams per liter to the
disadvantage of this locality.
Admitting now as correct the calculation which rated at 16 the
number of inspirations made by a man per minute, we observe that
the consumption of air is 8 liters in this interval of time, and
consequently is 480 liters in an hour. But we have already noted
for Mexico a loss of oxygen of 69 milligrams per liter. It is
therefore indisputable that in this capital one loses the benefit of 33
grams per hour or 794 grams of oxygen per day. (P. 65.)
256 Historical
After explaining thus the chief condition of the physico-physio-
logical problem, M. Jourdanet states that the ardor of the sun on
the heights of Anahuac must also act to diminish considerably the
density of the strata of air near the ground, and consequently the
intrapulmonary gaseous endosmosis.
When this has been established, he shrewdly compares respira-
tion in a pure air, but under low pressure, with respiration in air
with low oxygen content, but at normal pressure. Then answering
the objection taken from the work of MM. Regnault and Reiset
by M. Gavarret, an objection which had just found new strength
in the experiments of M. Fernet, he comments with reason that if
the chemical combination of the oxygen and the blood was abso-
lutely independent of pressure, one should live with ease not only
at the lowest barometric pressures, but also in air with very low
oxygen content, which no one will admit:
According to the opinion of M. Gavarret himself, the solubility
of oxygen in the blood is diminished when the quantity of oxygen
inspired is lessened. It is therefore indisputable that, however effec-
tive and necessary the affinity of the corpuscles for oxygen in the
act of respiratory endosmosis may otherwise be, the mere fact of the
rarefaction of this gas lessens the absorption of it at high altitudes
and thus causes real disturbance in the phenomena of respiration.
(P. 69.)
M. Jourdanet then adds the following interesting observation:
If the convictions which we have just expressed were to be shown
inaccurate in the results, compensation for the rarefaction and the
lightness of the atmosphere in Mexico would have to be made by
deep inspirations and by a respiration which in general was more
active than at sea level. It is commonly believed that this is the case
and this opinion is based upon the observation furnished by persons
who make a rapid ascent in the atmosphere or who make only a
short stay at high altitudes. It is completely erroneous. The truth
is that those who dwell at great elevations breathe less quickly than
men whose abode is near sea level. The rarity of the air, as we shall
see later, produces apathy of the muscular system. The chest also
feels its effects. I have often surprised the functions in the very act
by counting the respiratory movements of persons who were unaware
of it and who were in a state of complete repose. I almost always
noted a decrease in the number of expansions of the chest. Some-
times, fairly often, in fact, one forgets to breathe and is forced to
make up for lost time by taking deep inspirations. (P. 76.) ....
But this respiration, so calm in absolute repose, easily gains
amplitude under the influence of movement. (P. 87.)
The consequences of this decreased absorption of oxygen are
easily foreseen. The first is a decreased activity in the production
Theories and Experiments 257
of animal heat, at the very time when, on account of the altitude,
this production should be increased.
In fact, our author says very fittingly:
Prudent Nature at sea level has established laws which assist,
through the atmosphere, these variations in the production of human
heat. For in winter the cold air is denser, and contains a greater
part of the vivifying principle in a certain volume. The warmth of
summer, on the contrary, by expanding the atmosphere, gives the
lungs a proportion of oxygen in keeping with the small amount of
heat which the body must produce. Thus the source, from which we
draw the elements of our respiration, itself varies in a certain
measure, which, at sea level, is a kindness of Providence.
This is not true at high elevations, where the density of the air,
lessened by the decrease of the barometric pressure, is no longer
proportionate to the temperature surrounding us, but to the altitude
which we have reached. And note particularly this extremely impor-
tant fact: whereas at sea level the exterior causes which chill us take
care to give us the means of combatting this drop in temperature, in
Mexico, on the contrary, the decrease of pressure which produces cold
in the air alters the source of heat for us by compelling us to breathe
a rarefied atmosphere. So that, on the one hand, the increased expan-
sibility of the air and the easier evaporation chill us constantly, while,
on the other hand, the increased rarity of oxygen refuses us the
normal means of calorification.
Upon these data, so clear and so exact, the physiological pecu-
liarity of altitudes rests entirely. (P. 83.)
It is, therefore, not surprising to see that:
Persons in a state of repose chill very easily. Their lower limbs
are almost never warm. Muscular exercise would stimulate the
circulation and the respiratory movements; but the blood, deprived of
oxygen, produces apathy of the muscles and makes one prefer repose.
Here then appears the result of the experiment made by M. Becquerel
upon the muscle fiber which loses its contractility and becomes ener-
vated when it lacks contact with the arterial blood. (P. 86.)
Here M. Jourdanet meets the phenomenon described by all
mountain travellers, of exaggerated fatigue, pain in the thighs, and
heaviness of the lower limbs; he protests energetically against the
explanation of the Weber brothers, which was accepted by von
Humboldt and almost all later authors, although this explanation,
to use his apt expression, "does not bear careful examination":
In fact, if we estimate in square centimeters the surface on the
plane of opening of the cotyloid cavity, the diameter of which is 54
millimeters, we get a result of 22.89 square centimeters, which, multi-
plied by 1003 grams, a weight equivalent to a square centimeter of
surface, give us 23,645 grams, to represent the real weight in the
cavity of the joint. If we remember that many travellers have felt
258 Historical
the muscular fatigue which we are discussing when they had hardly
gone beyond a fourth of the atmospheric pressure, we shall see that
this phenomenon appeared when the thigh was still supported by a
weight of 17 kil. 734 gm. We do not understand why a member,
which may weigh at most 15 pounds, would have so little respect for
the 21 pounds surplus which it would drag along in its fall. (P. 89.)
The real reason, according to M. Jourdanet, is expressed thus:
This phenomenon appears when the blood, incompletely oxygen-
ated, causes the contractile power of the muscular fiber to be
considerably diminished. The abdominal member then refuses to carry
out its normal functions and warns by pain that the task is beyond
its powers. The same thing would happen to the other muscles of
the body, if one required of them the exaggerated efforts which ascent
demands from the muscles of the thigh. (P. 89.)
Summarizing:
The symptoms of the famous mountain sickness: vertigo, swoon-
ing, vomiting, — what do they amount to but cerebral anemia, for
want of the stimulus of arterial oxygen; congestion of the venous
system, and especially the portal vein and the liver; but, above all,
enervation of the muscular fiber for the same reason.
Always and everywhere: lack of the normal quantity of oxygen
in the circulation of the arterial blood. (P. 90.)
Most of the book is devoted, as its title indicates, to the study
of the diseases of Mexico. Everywhere there M. Jourdanet finds
predominant the effect of this anemia of a special type, "result of
an imperfect respiratory endosmosis". It is indeed, as he says
clearly in his subsequent works, this strange syndrome which,
awakening his medical shrewdness, caused him to reflect upon the
conditions harmful to respiration and metabolism presented by a
prolonged sojourn on the lofty plateaux of Anahuac.
I shall merely quote the following passage because it offers a
sort of summary of this remarkable work, and because we find
in it a part given to the pressure as a mechanical agent, simply
assisting its chemical action:
We have already seen the blood, feebly welcomed and lazily
expelled by the nervous centers, congesting the brain and the spinal
cord of weak persons, already injured by the climate. We shall
mention the disturbances of more than one sort of the alimentary
canal, several of which are due to the circulatory slackening and to
the capillary congestions of the intestinal venous system. The uterus
has attracted our attention by phenomena of the same nature. We
shall take the opportunity to say here that pulmonary congestions
are frequent in Mexico and too often are fatal. Finally, more
frequently than all the other organs, the liver imbibes blood and from
this source draws countless symptoms, the unfortunate consequences
of which are frequently reckoned among the causes of death.
Theories and Experiments 259
And so, beyond any doubt, altitude favors venous stases. When
they are superficial, one cannot deny that the decrease of the air
pressure acts in a purely mechanical sense towards this result. The
superficial capillary networks, deprived of their natural external
support, expand with an ease in proportion to the decrease in the
weight. If to this first cause you add a blood not sufficiently stimu-
lating for the arteries and too abundant in general for the veins, you
reach the etiological trinity: lessened external adjuvant, organic
sluggishness, general congestion of the venous system; a trinity the
effects of which will be directed by turns to different parts of the
organism, depending upon where the disturbances in innervation have
previously prepared for them. (P. 254.)
Two years later, there appeared a long memoir by the same
author.93
The mere title of this second work, The Anemia of Altitudes,
indicates the idea of M. Jourdanet: in his opinion, "the dwellers
at great elevations, above 2000 meters, are generally anemic", and
this condition is particularly evident to the eyes of the practitioner
by the syndrome. And yet the chemical analysis of the blood
strangely contradicts what the clinical observation revealed:
In 1849, while I was in Puebla, I wished to ascertain by
analytical examination of the blood whether the proportion of
corpuscles was reduced. I made my first investigation on a young
man twenty-five years old whom I knew to be suffering from gas-
tralgias and vertigo. He fell from his horse, and the consequences
of this fall made bleeding necessary. My analytical tests were made
on blood obtained in these circumstances. They showed me that the
proportion of corpuscles was 151/1000. I repeated my experiments
upon four young women who were bled following accidents. Their
pallor, their general prostration, and their nervous condition showed
that they were suffering from chloro-anemia, although auscultation
revealed no arterial murmur. Their blood furnished the normal
proportions of corpuscles. (P. 8.)
What is the explanation of this apparent contradiction? It is
that:
The principal duty of the blood corpuscles is to serve as aid to
the real agent of our life. When their proportion is reduced in the
blood, it is no doubt correct to say that the sickness is the result
of the decrease in corpuscles; but we would fix the immediate cause
-of the symptoms of the disease more accurately if we attributed its
existence to the decrease in oxygen. I think I am more justified in
expressing myself in this way because if, in the case of anemia, we
call attention, as it is natural to do, to the reduced proportion of this
gas in circulation, we see several causes which may produce this
circulatory anomaly, without finding it necessary to explain it by a
decrease in the number of corpuscles. That, exactly, is the case in
the anemia of altitudes. (P. 10.)
260 Historical
M. Jourdanet summarizes his opinion in the following proposi-
tions:
1. The corpuscles and the barometric pressure regulate the quan-
tity of oxygen in the blood;
2. Disturbances in either of these two forces must necessarily
affect hematosis;
3. Since oxygen is the chief vital agent, its decrease for lack of
corpuscles causes the weakness of anemic patients; its decrease in the
blood for lack of pressure must produce the same result;
4. For this reason persons breathing the atmosphere of great
elevations must have their health affected in the same way as those
suffering with anemia at lower levels;
5. The anoxemia of altitudes is therefore analogous to the hypo-
corpuscular anemia of the sea level. (P. 21.)
Since plethoric persons have a large proportion of corpuscles
in their blood, it is not surprising, as M. Jourdanet says, to see
them often:
Climbing the rugged sides of Popocateptl and at an altitude of
17,700 feet imbibing the complete elements of life, whereas their
travelling companions, of less sturdy constitution, succumbed to
mountain sickness. (P. 22.)
Then making a more detailed study of the chief phenomenon,
the general trend of which he indicated previously, and taking
into account the experiments of Magnus and M. Fernet and his
own, M. Jourdanet reaches the remarkable conclusions which we
give verbatim:
1. From 76 to 65 centimeters, partial vacuum acts only upon the
part of the gases of the blood which is held in true solution;
2. Under the influence of this first barometric decompression, the
release of carbonic acid is mmh greater than the loss of oxygen,
the result of which is greater freedom of action for the oxygen;
3. It is possible then that, since a moderate elevation does not
noticeably decrease the quantity of the oxygen in the blood, whereas
it removes a considerable portion of carbonic acid, it may act upon
man with a tonic and strengthening effect;
4. As to the portion of oxygen which a weak affinity allows us
to consider as being held by chemical action, its escape from the
blood results from lowered barometric pressure only when the pres-
sure approaches 60 centimeters;
5. We therefore should consider that the quantity of oxygen in
the blood is seriously diminished beginning in the neighborhood of
this limit, and it is then that the anemia of altitudes begins;
6. We can therefore understand that a moderate altitude may be
a powerful means of curing anemia, whereas this same disease is a
natural consequence of sojourn at a considerable altitude. (P. 37.)
Theories and Experiments 261
Finally, in 1864, a third 04 work repeats with new develop-
ments the ideas expressed in the works from which I have just
taken numerous quotations. However, I cannot refrain from ex-
tracting from one of his chapters on mountain sickness his clear
explanation of this syndrome, an explanation in which we need
to make no important change for the conclusions of the present
book:
A man who rapidly ascends to a very lofty point is deprived of
a certain quantity of oxygen from which he was accustomed to
receive a stimulating effect necessary for the full exercise of his
strength. Certainly, what is left him after his ascent is still capable
of maintaining life and even the regular action of the functions. But
man cannot endure without temporary symptoms a sudden reduction
which lessens the resources from which the nervous system is accus-
tomed to draw its power. The muscular fibers also refuse to perform
their task when their oxygen supply is decreased. We then see
appearing those phenomena which hemorrhages have made familiar
to us. As a result of the loss of blood, the organism, we know, sud-
denly loses an important part of its normal stimulus; the patient has
vertigo, his muscles weaken, nausea attacks him, and the more nearly
vertical his position is, the more quickly he is seized by syncope ....
The weakness produced by bleeding is evidently the consequence
of a sudden lack of oxygen through the loss of a certain quantity of
corpuscles, just as mountain sickness results from a more direct with-
drawal of the same gas. So that, beyond a doubt, an ascent beyond
3000 meters amounts to a barometric dis oxygenation oj the blood,
just as a bleeding is a disoxygenation oj the blood through the lack
of corpuscles. (P. 92.)
These works soon stirred up a controversy which was very bit-
ter. A French expeditionary corps had just been sent to Mexico,
and the conclusions of M. Jourdanet were anything but encourag-
ing for those who dreamed of the establishment of a Latin empire
supported by a French colony established on the lofty plateaux
of Anahuac.
Michel Levy, then director of the School of Military Medicine
and Surgery, was aroused and thought he should open a sort of
investigation of the accuracy of the data given by M. Jourdanet;
Dr. L. Coindet, head of the medical service of the second division
of the French army, agreed to take charge of this investigation.
The first letter sent by this observer to his hierarchic chief
censured the statement of M. Jourdanet about the slackening of
the respiratory movement:
A statement (said Michel Levy) which contradicts the opinion
accepted hitherto that, under the influence of reduced atmospheric
pressure, respiration is accelerated to compensate by the number of
262 Historical
inspirations for the diminished quantity of oxygen in the same
volume of air.95
In this document, L. Coindet 96 reports the results of 1500 obser-
vations made on Mexicans and Frenchmen on the high plateaux,
in which he counted the number of respiratory movements. I
give here the summary of his tables:
Frenchmen Mexicans
Below 16 inspirations per minute 54 25
16 inspirations 70 54
Above 16 inspirations 626 671
750 750
General average of inspirations per minute 19.36 20.297
In the presence of this mass of data (adds our author), doubt is
no longer possible, and it is certain that those dwelling here do not
breathe less quickly than men whose dwelling is 2277 meters lower.
Farther on, Coindet declares:
That, independently of the greater activity of the respiration, the
inspirations are generally ample, deep, and profound, and-that all the
more because they are less numerous.
He then states, without having made any exact measurement
of this point, however:
That thus equilibrium is always established, and that the function
constantly tends to adapt itself to the rarefaction and lightness of the
atmosphere.
Then, in a very sudden decision, which seems to indicate on
the part of our author a very great desire to be easily convinced,
Coindet does not hesitate to draw at once this important conclu-
sion from these observations on the respiratory rhythm:
That what has been written in regard to the insufficiency of the
oxygenation of the blood at great altitudes, as a consequence of an
alleged slowing of the respiration, should be considered unfounded . . .
It may very well be that the so-called Mexican anemia is merely the
yellowish complexion characteristic of the natives!
Next come observations on the pulse rate and the comparative
measurements of the chest capacity of Frenchmen and Mexicans.
We shall return to the second of these later. In regard to the
pulse:
I have felt it repeatedly (says Coindet) without any prejudice,
and I have even counted the heartbeats, which agreed with those of
the arteries.
In short, he finds as the average pulse rate, 76.216 for French-
men, and 80.24 for Mexicans.
Theories and Experiments 263
The second letter''7 treats of "acclimatization on the heights
of Mexico"; it contains only a summarizing description of the races
of Mexico and a little meteorological information. However, I
quote the following passage, which is rather interesting:
After crossing Cumbre, when we reached an elevation above 2000
meters, first respiration and circulation, and afterwards absorption,
exhalation, and metabolism underwent noticeable changes. We per-
ceived a tendency of the fluids of the body to move towards the
periphery, the result of which was derangement of the circulation,
various congestions, cerebral, pulmonary, and nasal hemorrhages,
several examples of which I have given; difficulty in breathing, which
made us pant; general discomfort, which made us consider the weather
heavy, although it was really lighter; difficulty in moving and greater
fatigue, and these symptoms were particularly marked in the men of
the 95th of the line, who had not remained long at Orizaba, like us,
and who had been transferred rather suddenly from sea level to a
fairly high elevation. Little by little, the organism of everyone, at first
in conflict with a medium for which it had not been created, adapted
itself progressively to this medium, and today, after a ten month
sojourn on Anahuac, it has been so transformed that it resembles that
of the Indian. (P. 817.)
The third letter 98 is much more important to us. In it is the
report of the analyses made in the laboratory of the School of
Mines of Mexico under the supervision of Professor Murfi, with
the purpose of measuring the quantity of carbonic acid formed in
a given time by dwellers on the lofty plateaux. Twenty-five per-
sons, 10 of whom were French, 10 Indians or half-breeds, and 5
Mexicans of European origin, were the subjects. The average re-
sults, for the French, for example, are given in the following table:
Number of inspirations per minute 19.6
Pulse rate 78.2
Quantity of air expired in one minute 5.90 liters
Average percentage of carbonic acid per minute 4.24
If we set aside the discussion which Coindet gives about the
petty differences of details noted among the representatives of the
different races on whom he experimented, we find that these
observations inspired the following reflections in him:
The average quantity of air expired per minute according to M.
Dumas is 5.3 liters at sea level; here generally we have about 6 liters,
when once the man is acclimated. This is logical, for since the air
of altitudes contains in a given volume less oxygen at a barometric
pressure of 0.58 or 0.59 meters than at 0.76 meters a greater quantity of
this air must be absorbed to compensate for the difference: this is at-
tained by a more active respiration; so that the air which is drawn into
264 Historical
the lungs and exhaled from them is always about a third of a liter for
each inspiration and each expiration.
While the air expired by man at sea level contains from 3 to 5
parts of carbonic acid per 100, our experiments show that on Anahuac
the average is just as high, since it is 4.36 for 25 subjects.
It has been shown by 103 observations made at sea level by MM.
Brunner and Valentin that the quantity of carbonic acid contained in
the expired air is 4.267%. M. Vierordt," who made nearly 600
experiments on this subject, reached nearly the same results. The
expired air contains on the average 4.336%.
Our average does not differ from the latter, if we take into
account the decrease in atmospheric pressure which, as is well known
(?), increases 'a little the proportion of carbonic acid exhaled.
We are not surprised, after this long enumeration of data, to
see Coindet cry out with an accent of triumph:
Absorption of oxygen, exhalation of carbonic acid constitute two
connected expressions, from the chemical point of view. On the other
hand, modification in the qualities of the expired air and the corre-
sponding changes in the composition of the blood are the two terms
of the physico-chemical problem of respiration.
There can be no doubt then about what one should think of the
alleged insufficiency of the oxygenation of the blood at high elevations.
The Gazette hebdomadaire contains another series of letters
addressed by Coindet to Michel Levy,100 under the general title:
"Statistical Studies of Mexico", devoted to pathology, meteorology,
etc.; they only rarely treat questions which are purely physiologi-
cal. We see that for this physician everything is settled by his
preceding researches, and that it is quite proved, as he says
frequently, that at high elevations man compensates exactly, by
the number and amplitude of the respiratory movements, for the
loss in oxygen caused by the lessened density of the air; so that
equilibrium is regularly maintained. I can find to be quoted
verbatim only the following passage, in which our author's opin-
ion about the cause of mountain sickness is shown.
June 5, 1863, (he says) in the company of Dr. Laval, I ascended
almost to the summit of Iztaccihuatl (4686 meters) .... Our mouths
and throats were dry; our legs were exhausted; our respiration was
panting, hasty, deep, often broken; our pulse, which was small, had
a rate of 128. But we did not yet feel the distress, headache, or
nausea, which constitutes mountain sickness, in which, by the way,
acceleration of the circulation no doubt plays a great part by its
congestive effect.
M. Jourdanet did not fail to answer the letters which con-
tradicted his physiological and medical statements on almost all
points and which gave the impression that there could be nothing
Theories and Experiments 265
accurate "in a book", these are the very words of Coindet, "so
opposed, I am proud to say, to all I have written". Without dis-
cussing what relates to pathology, we shall go straight to the
convincing reply which M. Jourdanet 101 made in opposition, not
to the data reported by Coindet, but to the conclusions which this
doctor drew from them:
M. Coindet states that the respiration is not merely accelerated,
but that it is ample, deep, profound. Now what do this amplitude,
this depth, and this profundity amount to? We find the definite
measure of them in the passage of his correspondence in which we
see that 25 subjects gave an average of 6 liters of air breathed per
minute, in 20 respirations. That is therefore an average of 30 centi-
liters of air for each respiratory movement. It is evident that this
volume of air represents only a very moderate thoracic amplitude . . .
Our colleague is no more fortunate when he states that, on the
great elevations of Anahuac, more air passes into the lungs in a given
time than at sea level; for the 6 liters which he collected in the sub-
jects of his observations are not above the very ordinary average
furnished by men from 20 to 30 years old at the pressure of 76 centi-
meters. And we should also note that, considering the rarefaction of
the air of Mexico, these 6 liters weigh only 6 grams, instead of 7.8
grams, the weight of the same volume of air at sea level ....
So, according to M. Coindet himself, at an altitude of 2277 meters,
respiration is not ampler, or deeper, or more active than at sea level.
(P. 150.)
The reply appears incontrovertible on this phase of the ques-
tion. The chemical considerations remain.
Here M. Jourdanet criticizes an obscurity in Coindet's wording,
which no doubt has already impressed our readers, but which
makes the reading of the different observations contained in the
memoir itself quite incomprehensible. In the table reproduced
above, we have copied verbatim these words: Average percentage
of carbonic acid per minute: 4.24. What does this information
mean? Does it refer to a percentage calculated in volume or in
weight? This question is asked in regard to each of the observa-
tions.
We are quite surprised (M. Jourdanet says naturally) at the
obscurity which reigns in the report of M. Coindet. Let us take, for
example, the first experiment:
"H. Staines .... Number of inspirations per minute 22; number
of liters of air in one minute 6.4; carbonic acid 4.64%."
Considering these 6.4 liters of air breathed by the subject of the
experiments, we cannot help thinking that the 4.64% of carbonic acid
indicates the proportional quantity of this gas in volume also. But
further on (Gaz., 1864, p. 36, first column), these figures are repeated
under the heading: Weight per 100 of carbonic acid expired in one
minute. Evidently the wording is not clear.
266 Historical
We repeat with M. Jourdanet: Evidently the wording is not
clear; but an important circumstance throws complete light on it.
It is the comparison which Coindet makes between the figure he
obtained and those of Vierordt, Brunner, and Valentin. These
physiologists very certainly meant the percentage in volume, and
Coindet could not have been confused about that, because the
passage we copied above is the word for word reproduction of a
new paragraph of the deservedly popular book of M. Beclard,10-
from which only the words "percent in volume" have been left
out. To M. Coindet, then, the matter concerns a proportion in
volume, and his own experiments would show, if this were the
case, a considerable decrease in the intra-organic combustions on
the Mexican plateau, since, the quantity (in volume) of carbonic
acid exhaled there being the same as at sea level, the quantity
in weight would evidently be much lower, in a proportion meas-
ured by the very decrease of the atmospheric pressure.
But here is another thing. M. Jourdanet, who was then in
Mexico, desirous of settling this doubtful question, asked M. Murfi,
"true author of these analyses", and obtained from him an answer
showing clearly that:
The experiments of the College of Mines gave an average of 4
grams and 51 centigrams of carbonic acid per 100 liters of air expired,
measured at a temperature of 14 degrees and at a pressure of 58
centimeters.
The contradiction is glaring: Coindet specified volumes, M.
Murfi states that it is a matter of weights, and M. Jourdanet,
naturally giving more credence to the statements of the Mexican
chemist, draws from them a really crushing conclusion for his
adversary:
It is therefore unquestionable (he says) that the subjects of the
experiments of the College of Mines produced 4.51 grams of carbonic
acid per 100 liters of expired air. On the other hand, the report of
M. Coindet, agreeing in this with the statement of M. Murfi, says that
the quantity of expired air was on the average 6 liters per minute.
Who can doubt then that if 4.51 grams of carbonic acid correspond to
100 liters of air, the 6 liters expired by the subjects of the experiments
contained 27 centigrams. It is therefore certain that the quite unde-
niable result of the respiratory proportion of the College of Mines
was that the subjects from twenty to thirty years old produced 27
centigrams of carbonic acid per minute, that is, 16 grams and 20 centi-
grams per hour.
The conclusions of M. Coindet do not agree with these figures;
for not only did these alarming figures not authorize him to say that
respiration in Mexico is identical with that at sea level, but they
Theories and Experiments 267
indicate a danger which would justly make one fear sojourn in lofty
Anahuac; since, according to these experiments, the carbonated respir-
atory combustions would not be half there what they are at sea
level. The analyses of the College of Mines therefore leave us in great
anxiety. I notified my colleagues of the Society of Medicine of Mexico,
who were sufficiently affected by them to vote new surveys. (P. 151.)
To this undeniable conclusion, Coindet 10:! tried to reply in his
turn. Let us set aside the mere assertions and the digressions of
acrimonious polemics, although they are numerous, and come to
the root of the matter, the contradiction which we revealed above:
M. Michel Levy (he says) and the members of the Society of
Medicine of Mexico know the reply which I made to the statements
of M. Jourdanet. I proved that the volume 3.90 per 100 of air at a
temperature of 14 degrees and a pressure of 58, which was given me
by the weight 4.51 per 100 of air also at a temperature of 14 degrees and
a pressure of 58, furnished, because of the greater quantity of air
expired (6 liters instead of 5.3 Dumas), 295.13 grams of carbon con-
sumed in 24 hours, or 12.30 grams in one hour, and we know the
averages established at sea level by MM. Dumas, Andral, Gavarret,
Valentin, Brunner, Vierordt, etc. It is quite certain, I assert, that my
subjects would not have expired more than 3.3 liters of air at sea
level.
I confess for my part that I do not understand this very well,
and it would have been desirable that Coindet should copy in his
letter the proofs which he had sent to M. Michel Levy. First, let
us note that this time the 4.51 are no longer for him a measure 104 of
volume, as that resulted evidently from the new paragraph which
we mentioned, but a measure of weight; it is, as M. Murn said,
the weight of carbonic acid contained in 100 liters of air expired
at 14° and 58 cm. But from that point, the reasoning and the calcu-
lation of M. Jourdanet are unassailable. If 6 liters of air per min-
ute pass through the lungs, that makes 360 liters in an hour, con-
taining 360 x 4.51 grams = 16.23 grams of carbonic acid. The re-
searches of Andral and Gavarret 105 give an average, between the
ages of 20 and 40, of 12.2 grams of carbon consumed, which corre-
sponds to 44.07 grams of carbonic acid. The difference is enor-
mous, so enormous that, for my part, I think that there is a funda-
mental error in the analyses which are the basis of his reasoning.
Let us see now what Coindet's reasoning is. And first, let us
note that he takes a strange cross-road: "I have proved", he says,
"that the volume 3.90 per 100 of air at a temperature of 14 degrees
and a pressure of 58, which was given me by the weight 4.51 per
100 of air also at a temperature of 14 degrees and a pressure of
58 . . ."
268 Historical
These are painful and useless calculations; why change a weight
into volume to find again a quantity in weight? Let us, however,
make them again, because, if their apparent result is favorable,
we shall find considerable errors in them.
A liter of carbonic acid at 0° and 76 cm. of pressure weighs 1.966
grams. Therefore, 4.51 grams of this gas represent under these
4.51
conditions of temperature and pressure liters, and at 58 cm.
4.51 liters x 76, 4.51 liters x 76 (273 + 14)
and at 14° = 3.160 liters.
1.966 x 58 1.966 x 58 x 273
So the expired air contained in volume 3.16% of carbonic acid,
and not 3.90 as Coindet said, so that all his subsequent results are
decidedly wrong.
Better still: accepting the figure of 3.90% (a proportion, which,
by the way, does not vary, as Coindet seems to think, with the
pressure and the temperature) we get final results very different
from those he records. In fact, the men whom he observed
breathed per hour 360 liters of air, which consequently contained,
according to him, 360 x 3.9 liters = 14.04 liters of carbonic acid,
at 14° and 58 cm., representing at 76 cm. and 0°,
14.04 liters x 58 x 273
= 10.19 liters.
76 (273 + 14)
Now since 1 liter weighs 1.966 grams, we would have for the
production per hour only 1.966 grams x 10.19 = 20.03 grams; and
as there is a weight of 27.68% of carbon in carbonic acid, the
weight of the carbon consumed per hour would be
1.966 grams x 10.19 x 27.68
= 5.54 grams;
100 *
which is far from the 12.30 grams announced by Coindet.
On the contrary, the calculation of M. Jourdanet here finds a
complete verification by counter-proof. In fact, it results from
what we have just said that really, according to the experiments
of Coindet, his men exhaled per hour
360 liters x 3.16 = 11.376 liters
of carbonic acid, representing at 76 cm. and 0°, 8.258 liters, which
weigh 16.23 grams, a number exactly like the one we found before
according to M. Jourdanet.
Theories and Experiments 269
It is for the reader to decide whether, after such a surprising
argument, one should jeer, as Coindet did, at the "competency" of
the man who very courteously criticized his mistake. At any rate,
we can now easily evaluate the following conclusions, which he
boldly 10° formulated:
4. The average of the carbonic acid expired on Anahuac, with
diet and conditions equal, is not lower than at sea level.
6. The quantity of oxygen circulating in the blood is the same at
high elevations as at sea level; and with similar and equally satis-
factory hygienic conditions, the efficacy of hematosis is the same also.
17. Under ordinary conditions, residence in Anahuac does not
seem to lessen permanently and injuriously the total of the gases
which circulate in the human body.
As for me, I do not hesitate to say that in the work of Coindet
nothing justifies this last conclusion, and everything in it contra-
dicts the first two. To tell the whole truth, I confess that I can-
not accept as accurate even the analyses which are the foundation
of them; there must be some mistake in the experimental method
or in its application. I shall merely say that the quantity of air
upon which the analysis was based was much too small; M. Murfi
had the respiratory movements carried on in his apparatus for a
half -minute ; Andral and Gavarret had them continued from 8 to 13
minutes. Furthermore, no one took care to collect the air which
passed through the nostrils. However disposed I am to think that
in Anahuac the intensity of the organic combustions is really les-
sened, I refuse to believe that it is one-half less, as would be
demonstrated if we considered as accurate the figures furnished
by the work of Coindet himself. To sum it up, from the point of
view of the chemical phenomena of respiration, there is absolutely
nothing left of this work.
One of the surgeons of the Mexican expedition, M. Cavaroz,107
shortly afterwards published a memoir, the observations and con-
clusions of which are exactly like what M. Jourdanet had already
said.
He first made a great many measurements on French soldiers
and found that at an altitude of 1712 meters the general average
of respirations was 19% and the pulse rate 65 %•:
He first draws this conclusion that: on the lofty plateaux of
Anahuac, there is established in the European a supplementary
respiration, intended to compensate by the number of respiratory
movements for the loss of oxygen for hematosis resulting from the
rarefaction of the atmosphere ....
270 Historical
But, he soon adds, we need to know whether this compensation
is complete, and whether, after all, there is no loss of oxygen, and
whether the hematosis is as normal and perfect as at sea level. I do
not think so, for according to the average ratio of 18 respirations for
67 heartbeats, the number of heartbeats for 19% respirations should
be 67 V2. It is only 65x/4; therefore there is a loss of 2V4 heartbeats;
therefore the circulation is slackening to a certain degree, and the
physiological condition is disturbed.
The rest of the work of M. Cavaroz contains observations tend-
ing to prove that on the lofty plateaux the European loses his
liveliness and strength, and that if he falls ill, he rapidly passes
into a state of prostration. So, in his opinion, perfect acclimatiza-
tion is by no means proved. The resemblance between these ideas
and those of M. Jourdanet is quite striking.
However, no one has paid any attention to it, and henceforth
authors will speak of no one but Coindet, and we must confess
that without exception they will side with him against M. Jourda-
net, which proves, among other things, that it is much easier to
read conclusions than to discuss a memoir.
So in the article Air which M. A. Tardieu ln" wrote for the Dic-
tionary of Practical Medicine and Surgery, the learned hygienist
devotes a page to the study of the physiological effects of rarefied
air. It is filled by a rapid review of the ideas of M. Jourdanet and
the works of Coindet; I take from it these characteristic lines:
After what has just been said, we see what we should think of
the alleged insufficiency of oxygenation of the blood at high altitudes.
Moreover, M. Tardieu gives no explanation.
The article Altitudes which M. Leroy de Mericourt wrote for
the Dictionnaire Encyclopcdique two years after deserves the same
reproach. But before discussing it, I must say a few words about
a very odd book, published in 1863 by Dr. Foley.109
When we come to the study of compressed air, we shall have
to give a lengthy review of it. We shall see that in the opinion
of this physician, the compression exerted by the air plays the
principal part: "When one enters the caissons", he says, "he is
flattened." He naturally brings the same preoccupation of a me-
chanical type to the study of mountain sickness:
A traveller climbs a mountain. The higher he ascends, the
weaker he feels, and the more his subcutaneous veins distend. He
finally becomes ill. Why?
The periphery of his body is no longer compressed. A comparative
vacuum has been formed around it. The blood has accumulated
there. The brain has therefore failed. The aeronaut has fainted.
(P. 63.)
Theories and Experiments 271
Let us add that farther on M. Foley declares that nausea,
cramps, etc., are the sign of "insufficient hematosis".
In his opinion, it is the presence of the air sacs which saves
the bird from the symptoms of decompression; the shocks* with
which he would be threatened on his return as workmen are when
they leave the caissons (see later, Title II, Chapter III) are spared
him because of the elastic tension of the gases contained in the
sacs. For that, the bird that is mounting needs only to close
its beak and its nostrils; but perhaps we may be permitted to
ask how it can breathe then.
A distinguished veterinarian, M. Liguistin,110 who was in com-
mand of this service during the Mexican expedition, found himself
confronted with the same problems as the military physicians. He
seems not to have known of the heated discussion the principal
points of which we have just summarized:
"In his opinion, moreover, the effect of the decrease in the density
of the air is very well known." (Vol. Ill, p. 583.)
As to symptoms observed in animals, he states that the respira-
tory disturbances noted by doctors seem not to have attacked
beasts of burden:
Would the large solipeds bear more easily than men the effect of
an air with low oxygen content? Would the lymphatic temperament
with which they are endowed explain sufficiently the less urgent need
of a denser air? However we know very well, and have already said
so, that the atmospheric pressure most favorable to animals Is also
that found at sea level and in places of moderate elevation, where
the mercury column registers about 76 centimeters on the barometer;
that, if we place a living animal in a vacuum, the air within it, no
longer meeting any resistance, expands, the animal is distended and
dies; that it is the air pressure which keeps the fluids in the vessels
of animals and prevents them from escaping. Therefore, when the
barometer drops a few degrees, the blood must evidently flow towards
the periphery; then we observe difficulty and acceleration of respira-
tion, slackening of the circulation, weariness, prostration, and lack
of interest. If in this situation our animals were endowed with the
power of speech, they would probably tell us, as men do, that the
weather is heavy, thus taking the effect for the cause, for we know
that the rarer the air is, the lighter it is. It is unnecessary to explain
why the respiration is more hasty. We know well enough that, since
the air necessary for life is extremely rare, the respiratory acts must
be more frequent to produce the same result. It is still more unnec-
essary to add that when the air becomes rarer, one might die of
asphyxia. In a rarified air, thoracic inflammations and hemorrhages
must necessarily prevail. And yet we have not observed this, and
that is why we think that we are authorized to assert that the reduced
atmospheric pressure on the lofty plateaux of Mexico does not have
272 Historical
the peculiar influence upon our animals which we have observed in
men living in the same medium. We mention the effect of the rare-
faction of the air only in explaining the exaggerated distention
accompanying the numerous indigestions observed in our horses and
mules during the period of the siege. (Vol. Ill, p. 658.)
In a special work, this same veterinary gives an account of a
series of very unusual symptoms, observed in the animals of the
expeditionary corps, in the crossing of Rio-Frio (3300 meters) .
The animal passes from health to sickness without any preliminary
symptoms. The system is in a state of general tension, especially the
muscular system. The eyes are fixed, wild, brilliant, the face con-
tracted and the pupil dilated. The hind limbs and the whole hind-
quarters are the seat of spasmodic movements which are very
definite and easily detectable. The muscles of the stifle and the thigh
display partial quiverings.
The mouth is filled with a white, foamy, and very abundant
saliva. The jaws are in a state of permanent contractility. There is
certainly an over-stimulation of the salivary glands. There is a mani-
fest desire to vomit. Frequent efforts with belching are easily
observed. The belly is not distended. There are a few slight colics
shown by a little uneasiness, but the animals do not lie down, aroused
instinctively by the desire to urinate or defecate. The genito-urinary
system is over-stimulated: there is a stubborn and painful erection
of the penis. The conjunctiva is in its natural state and shows no
very perceptible changes; it is moist and very slightly bloodshot. The
capillary blood system is not visibly changed. The heartbeats are
strong and tumultuous. One can see at a distance, without resorting
to auscultation, the hasty movements of diastole and systole, and can
count the throbs of this organ by looking from behind the knee; . . .
and yet, strangely enough, the state of the pulse is not appreciably
modified in its normal rhythm.
The nostrils are dilated. The expired air is hot; respiration is
accelerated. The inspiration is shallow and the expiration deep. The
respiratory muscles are contracted and tense, and the flanks, drawn
upward, are separated by extremely pronounced projections. They
rise and fall up to twenty or twenty-five times per minute.
There is rather general prostration of the nervous system than
evident over-stimulation of the brain.
The symptoms which we have just listed continue for several
hours without increasing and then disappear evidently as the effect
of suitable measures. (Vol. IV, p. 258.)
This strange series of symptoms apparently so dangerous,
which, however, never brought on any serious consequences, sug-
gested to M. Liguistin the idea of poisoning. Not all of his col-
leagues shared his opinion; "some explained the symptoms in ques-
tion by blaming chiefly the rarefaction of the air, slow asphyxia
Theories and Experiments 273
M. Liguistin himself realized that this element might have an
important etiological part:
Certainly there is no doubt (he says himself) that at the season
when we crossed Rio-Frio, the period of great heat, that a consider-
able increase in the temperature, causing evident rarefaction of the
air, added to an elevation of 3302 meters above sea level, and
producing by this altitude a decrease of 3 ¥2 kilometers in the height
of the atmospheric column, had the immediate result of decreasing
considerably the quantity of respirable air and producing symptoms
characteristic of such causes. We should have liked to be able to
prove this physical point by the barometer, during the different
conditions of the atmosphere; for that alone would have furnished
the real explanation of the swelling of the abdomen frequently
appearing in the animals of the expeditionary corps during our
crossing of Rio-Frio. However, although this rarefaction was not
demonstrated experimentally, its existence is nevertheless undeniable.
In Mexico City, observation showed that the atmospheric pressure
was only 58 degrees. We may therefore estimate it for Rio-Frio at
approximately 55 or 56, which would cause a decrease of 20 degrees
from normal atmospheric pressure. Is it illogical to suppose, after
that, that animals cannot be placed for even an instant in such a
medium without their organism feeling some effects of it? Evidently
not; and we were all the distressed, but not surprised, witnesses of
the harmful effect which so rarefied an atmosphere can produce upon
the health of large solipeds; I mean this second pathological scene,
which appeared again more definitely at Rio-Frio, and which brought
a moment of turmoil and confusion (indigestion with distention).
(Vol. IV, p. 262.)
In short, M. Liguistin persists in the idea of poisoning, the
harmlessness of which he explains by the partial neutralization
produced by other plants simultaneously ingested. By searching
in the vicinity, they found a sort of scilla, to which they attributed
the symptoms. Experiments made with the leaves suspected gave,
however, only one interesting result: the firm refusal of the horses
to taste them, even after a fast of 48 hours. As for poisoning
obtained by aqueous extract, ingested in the animals by force,
they by no means resemble the symptoms observed during the
crossing of Rio-Frio. Whence we conclude, in direct opposition
to our author, that these symptoms were due exclusively to the
rarefied air.
I now come to the article of M. Leroy de Mericourt,111 an article
to which the name and the special qualifications of its author
gave much credit, and which is still quoted constantly.
However, it does not contain any personal observation, and the
only really original idea in it is due to Professor Gavarret; but
it gives, in an elegant style, a summary of the data previously
274 Historical
observed and the theories put forth. The most interesting part
consists of a very harsh criticism of the works and opinions of
M. Jourdanet, whom he considers completely vanquished by Coin-
det. According to him:
The proportion of carbonic acid in the air expired, as indicating
the activity of hematosis on altitudes of more than 2000 meters,
showed that the average exhalation of this gas is not less than it is at
sea level.
We have already shown what one should think of this asser-
tion, to which the very figures of Coindet would give much too
complete a contradiction, in our opinion.
Then, finding the comparison made by M. Jourdanet between
mountain sickness and bleeding, and expressed in these striking
and accurate terms: "An ascent above 3000 meters is a baro-
metric disoxygenation of the blood, just as a bleeding in a cor-
puscular disoxygenation", M. Leroy de Mericourt finds nothing
better to say about it than to qualify it as strange:
Moreover, (he says) a priori, the objection may be raised against
M. Jourdanet that the absorption of oxygen by the venous blood is
not a purely physical fact, the result of a simple solution, but that
chemical forces play an important part in this fixation of oxygen.
I was very desirous of reporting this opinion because it shows
well what the sentiment of the most learned and the best authori-
ties was in 1866. We must, in fact, wait for the theory expressed
by M. Jourdanet, the accuracy of which I have demonstrated ex-
perimentally, to be considered soon as a thing so simple and evi-
dent that everyone will claim to be its originator, or at least will
refuse it any merit of originality.
I now come to the passage penned by M. Gavarret.
After reviewing a few principles of elementary physics, the
learned professor of the Faculty of Paris continues in these words:
When he ascends a lofty mountain on joot, man accomplishes a
quantity of mechanical labor which varies with the weight of his
body, the height of the ascent, the nature and the disposition of the
ground on which he walks. To the mechanical force which he thus
expends there corresponds a consumption of a determined quantity
of the organic materials of his blood, the combustion of which pro-
duces no thermic effect. Independently of the quantity of heat
necessary for the maintenance of his own temperature, the respiratory
combustions must therefore furnish the calorific equivalent of the
mechanical force expended during the ascent. To understand thor-
oughly the consequences of this forced increase of the respiratory
activity, let us give our attention to a specific example.
Theories and Experiments 275
An adult man, of good constitution, weighing 75 kilograms, has
ascended, on foot, to an altitude of 2000 meters on the side of a
mountain. He has thus accomplished a useful work of 150,000 kilo-
grams, representing 353 units of heat, the thermic effect of which is
zero, since they are transformed entirely into mechanical force, and
which are furnished by the respiratory combustions. Since eight
tenths of this transformed heat comes from the combustion of carbon,
the creation of the mechanical force corresponding to the useful work
accomplished during the ascent requires the production of 65 liters
of carbonic acid, above 22 liters of this gas which the man forms per
hour in his general capillaries to maintain his own temperature. The
consequences of the production of so great a quantity of carbonic
acid in the body are apparent. The consumption of the organic
materials of the blood is excessive, and the powers are rapidly ex-
hausted. The respiratory and circulatory movements are considerably
accelerated, on one hand to render possible the absorption of all the
oxygen necessary for such active combustions, and on the other hand
to rid the blood of such a proportion of dissolved carbonic acid. When
the pace is slow, the force expended in a given time is slight, and
the functional disturbances are not great.
But if the ascent is rapid, the exhalation of gas, though very much
activated, is not enough to maintain the normal composition of the
blood, which remains saturated with carbonic acid; then respiration
becomes uneasy; the dyspnea is extreme, and is accompanied by head-
ache, vertigo, and drowsiness .... We easily understand why a halt
of a few instants is enough to dissipate all these symptoms.
As soon as the man is resting, the expenditure of energy ceases,
the activity of the respiratory combustions drops rapidly to the degree
strictly necessary for the maintenance of his temperature, the utili-
zation of oxygen is only 22 liters per hour, the blood is very quickly
freed of the excess of carbonic acid which it contains, and all the
disturbances of the respiratory and circulatory functions disappear
at the same time ....
As a result of these considerations, we think that we are author-
ized to say that the larger part of the functional disturbances
characteristic of mountain sickness should be attributed to a true
intoxication by carbonic acid dissolved in too great proportions in the
blood. To express our ideas completely, we shall add that an intoxi-
cation of the same sort, the inevitable result of too great an expendi-
ture of energy, is one of the principal causes of the serious symptoms
observed in overdriven animals.
This interesting and original theory, supported by indisputable
calculations and the great authority of the learned professor of
medical physics, should gain great success and be epoch-making in
science. Henceforth, all will vie with each other in repeating it;
already Dr. Aug. Dumas 112 has been the first to do so in his inaugu-
ral thesis.
But the theory of M. Gavarret does not satisfy him; he ac-
cepts and supports with well-made calculations the theories of the
276 Historical
Weber brothers on the tendency of the head of the femur to sepa-
rate from the cotyloid cavity in expanded air. The objections of
M. Jourdanet do not affect him, as we see. That is because he
does not consider the work of this learned physician very impor-
tant; in his opinion, Coindet has completely refuted such errone-
ous statements:
What becomes then (he cries) of the alleged insufficiency of
oxygenation of the blood at high altitudes? and what shall we say
of all the theories which M. Jourdanet has based upon this idea?
As to the headache, vertigo, and loss of consciousness experi-
enced by von Humboldt and other travellers, Dumas explains
them "in a wholly mechanical manner"; to tell the truth, he
merely copies an explanation already given by Pravaz:
Barry has shown that at each expiration, the course of the blood
is slackened in the jugular veins. Therefore it is easy to understand
that, in a person who has reached the summit of a lofty mountain,
where his hampered respiration forces his thorax to make hasty
movements, his venous blood experiences a stasis in the jugular veins
and even flows backward, possibly causing a congestion of the nervous
centers and all the symptoms which result from that.
M. Scoutetten,111 whose work appeared the next year, is satis-
fied with copying the principal parts of the article Altitudes, and
particularly the quotation from M. Gavarret, whose opinion he
adopts wholly.
As he seems besides to attach much importance to the varia-
tions of the weight sustained by the human body under different
barometric pressures, he took the trouble to draw up a long table
in which are listed the amounts of this weight in all the mineral
water spas.
We learn from this that a man who sustains 15,345 kilograms
at sea level is relieved of 406 kilograms at Vichy, of 1015 at Saint
Gervais, of 1905 at Mont Dore, and 2744 at Cauterets, the highest
of the spas.
Is it among such ideas that an author takes his stand whose
Proceedings for 1867 publish a note which is not conspicuous for
clarity? I do not know and leave the reader the task of decid-
ing: 114
M. Kaufmann submits to the judgment of the Academy a memoir
on the mechanical effect of the air upon certain physiological functions
in which it does not usually play a part.
To ascertain, the author says, the mechanical effect exerted upon
different parts of the organism by the pressure of the air, I began
experiments to measure the air; some in which I measured the
Theories and Experiments 277
changes produced in different physiological or pathological states by
variations in the weight of the atmosphere; others in which I produced
these variations artificially. Those whose results I am submitting to
the Academy today refer to the different periods of generation in
mammals from conception to the time of delivery.
In the book which he published at the time of his return to
France, Coindet lir' returns to the question of the quantity of car-
bonic acid formed by men who live on the lofty plateaux. Evi-
dently he felt ill at ease on this ground, for in a work of two vol-
umes, containing more than 650 pages, he devotes only 5 to this
important subject. And yet what could be more convincing in
favor of his point than to dwell upon this demonstration that the
intra-organic combustions are as active at high altitudes as at sea
level? Anoxemia, against which he was battling, would be com-
pletely disproved. I confess that at first I expected to find new
experiments in this book; there are none, and the explanation of
the data is infinitely less complete and detailed in it than in the
letters addressed to Michel Levy.
This is soon explained, for first we record a valuable confes-
sion; "I was mistaken", says Coindet (Vol. II, p. 90), "when I
formerly wrote weight instead of volume." There is a point
gained, and, as I had shown when I recalled the passage copied
by Beclard, the notorious 4.51% in 1864 represented to Coindet a
proportion in volume, although he said the opposite in his 1865
letter. But then, if there is 4.51% of carbonic acid in volume in
the air, since the subjects were breathing at the rate of 6 liters
per minute, or 360 liters per hour, that makes in one hour 360
liters x 4.51 — 16.23 liters of carbonic acid expired.
Since we are working at 14° and at 58 centimeters, this volume
corresponds., at 0° and 76 cm., to 11.77 liters; and as a liter weighs
1.966 grams, the production of carbonic acid per hour would be
23.14 grams, giving 6.40 grams of carbon consumed. Once more
we are far from the 12.30 grams announced triumphantly by
Coindet.
But he thinks better of it:
We must not lose sight of the fact (he says) that 4.52% in
volume, the average amount of carbonic acid exhaled in one minute,
has been removed from an air at a temperature of 14°, and a pres-
sure of 58 cm., brought to a temperature of 0°, and a pressume of 76 cm.
... so that 6.125 liters, average amount of air expired in one minute,
disregarding the Frenchmen who had lately arrived and were not
acclimated, give us 367.55 liters in one hour . . .
When the average of 4.52% of carbonic acid exhaled in one min-
ute is accepted, we can establish the following proportion:
278 Historical
100 : 4.52 : : 367.55 : x = 16.62 liters of carbonic acid per hour.
At sea level, 1.85 liters of carbonic acid contain 1 gram of carbon,
which gives us 9 grams very approximately consumed in one hour. . . .
This figure is quite different from the 12.30 grams of the first
work. And yet how was it obtained? First by taking the quan-
tity of air expired from 6 liters to 6.125 liters; then by declaring
that in the calculations the air was reduced to 0° and 76 cm.; but
Coindet forgets that he said exactly the opposite before:
I have proved that the volume 3.90% of air at 14° and 58 cm. fur-
nished me by the weight (let us not forget that now it is the vol-
ume) 4.51 of air also at 14° and 58 cm
In another passage, he is no less explicit
Since the quantity of air expired per minute, as admitted by
M. Dumas, is 5.3 liters at sea level, in Mexico City . . . we have about
6 liters. This was logical, for since the air at high altitudes contains
less oxygen in a given volume, a greater quantity of this air had to
be absorbed to make up the difference.
It is not therefore, in our opinion, 9 grams, but 6.40 grams of
carbon consumed in an hour that are given by the figures of
Coindet himself. But even with 9 grams, we must realize that
we are far below the average figure of 12.2 grams found by
Andral and Gavarret. Coindet cannot conceal it, but he does not
seem at all disturbed by it:
Our average of 9 grams (he says calmly), lower than that found
by some authors, does not cause us, for reasons given above, to con-
sider the respiratory combustions of carbon as perceptibly lower on
the lofty plateaux than they are at lower levels.
What are these reasons then? First, we see, is that
Our Creoles were students in the School of Mines, on the day
before their final examination for the year, sitting studying all day
long, and under these circumstances the expired air has undergone
little change;
And second, that
The Indians had an insufficient diet and used alcohol habitually;
And third, that
There were losses through the nostrils!
I think it would be useless to continue. I can only repeat what
I said above: from the chemical point of view, there is nothing,
absolutely nothing, left of the work of Coindet; and as the experi-
ments which we have just shown to be so unsatisfactory are the
Theories and Experiments 279
basis of his whole physiological argument, we see that his position
is untenable.
I should certainly not have spent so much time on a work
which has had far too much publicity, if it was not still quoted
as an authority by persons who preferred to trust to its peremptory
conclusions rather than to make the painful analysis through the
meanderings of which we have led our readers. And the latter
have had the opportunity to see that even if the a priori asser-
tions and the statements of conclusions are clear, the experiments
themselves and the calculations based on them contain only ob-
scurity, confusion, or error.
M. Gavarret 116 did not adhere to the theory which we reported
above, and which he had given in the form of advice to M. Leroy
de Mericourt. When he wrote the article Atmosphere for the
Dictionnaire Encyclopcdique, he was led to investigate the effects
of decreased pressure, without the addition of fatigue, exertion,
and the production of carbonic acid imposed by mountain ascents.
Reaching the study of causes, as an experienced physicist, he first
opposes the opinion that the lessening of the weight sustained by
the body may have some effect; he properly invokes against this
error the principle of the incompressibility of liquids, and conse-
quently of the body. But in giving his attention to this point,
strangely enough, he returns to the ideas of Robert Boyle:
The disturbance which accompanies the decrease of the barometric
column is really the effect of the pressures from within outward
exerted by the vapors and the gases imprisoned with the body ....
We must fix our attention upon the gases of the blood which, under
the effect of a considerable and very rapid drop of the barometric
column, may cause serious symptoms. The blood, in fact, contains
oxygen, nitrogen, and carbonic acid in the state of simple solution.
When the outer pressure diminishes, these gases tend to separate from
the blood, push the walls of the vessels from within outwards, and
distend the pulmonary and general capillaries, the walls of which may
be ruptured because of their thinness and lack of resistance. Such
is the mechanism of the production of hemorrhages, sometimes slight
and temporary as their determining cause when they appear on ex-
ternal surfaces, sometimes serious and even fatal, when they have the
interior of some vital organ as their seat. (P. 153.)
But M. Gavarret makes haste to apply a proper restriction to
this:
Symptoms of this sort may no doubt be produced in persons who
are very rapidly moved to great altitudes; but that is not the case
with travellers who gradually ascend from sea level to the highest
plateaux on earth. In the latter, the laws of physics governing gases
and their solubility .... reestablish harmony .... (P. 154.)
280 Historical
In other words, the explanation given by the learned professor
can be applied, according to him, only to laboratory experiments
performed on animals; mountain climbers and aeronauts are not
amenable to it.
The argument brought by M. Gavarret against the part which
so many authors had given to the decrease of the weight sustained
by the body seemed to have exposed this error; the important ex-
periments of Rudolph von Vivenot 117 seemed, on the other hand,
to give it new authority. In fact, the Viennese physician proved
very clearly that in rarefied air the depth of the respirations and
the respiratory capacity diminish considerably.
These experiments were made at the Johannisberg establish-
ment, in the apparatuses set up by Dr. Lange; some had as their
purpose the study of compressed air, and those we shall discuss
later; the others, of which we shall speak now, related to rarified
air.
When we take into account the altitude of Johannisberg, where
the average height of the barometer is 742 mm., we see that if
the decompression reached in the apparatus was 318 mm., the
actual pressure was 424 mm., which corresponds to an altitude of
4470 meters above sea level.
Under these conditions, as I said a moment ago, the amplitude
of the respirations diminished considerably:
Dr. Lange and Dr. Mittermaier, whose pulmonary capacity shortly
before at normal pressure had been 3942 cc. and 4237 cc, could only
with the greatest efforts expire 3448 cc. and 3842 cc, of air which
was admitted to the receivers of the spirometer. Their respiratory
capacity therefore had diminished 494 cc. and 394 cc. respectively.
On an average, we can deduce from the above figures as a normal
average respiratory capacity 4090 cc, as respiration in rarefied air
3646 cc, consequently as average decrease of pulmonary capacity 444
cc, to which we must add that these 3646 cc. of rarefied air represent
only 2084 cc. of normal air. (P. 7 of the separate printing.)
The frequency of the respirations has considerably increased,
working inversely:
The number of respirations rose in me from 14-15 to 18; in
M. de G. . . ., from 17 to 21, and at another time, from 17-18 to 19;
in Dr. Lange, from 15 to 21; in Dr. Mittermaier, from 7.5 to 9.5 per
minute. As to the consecutive duration of this effect, it could not be
noted, because no observations were made following the experiments
in rarefied air. (P. 11.) . . .
As to the depth and rhythm of respiration in rarefied air, an in-
crease in the depth of the inspirations is noted. This, then, is the
first case in which the effect of rarefied air seems to agree with that
Theories and Experiments 281
of compressed air, although the causes are opposite. Whereas in com-
pressed air there is a deeper inspiration spontaneously, as a mechani-
cal effect of the increase in pressure, it is, on the contrary, the need
of getting air, which, since it cannot be satisfied in rarefied air by
normal inspirations, necessarily produces deep and forced inspirations.
One experiences at the same time a feeling of uneasiness, oppression,
during which the inspiration is especially difficult, because, even in
atmospheric air, it requires more energy than the expiration, whereas
the latter, in rarefied air, is made more easily and more quickly.
(P. 16.)
Vivenot also made observations on the pulse rate. It rose from
78 to 80 in Dr. M., from 73 to 82 in Dr. L., from 61 to 76 in M. de G.,
from 80 to 105 in Vivenot himself.
A veterinarian of the Royal Corps of English Engineers, Fleme-
ing,118 published in 1867 a work in which he reports a fairly large
number of travellers' observations, and at the head of which he
expresses his theoretical opinion about the effect of decompres-
sion:
If the pressure is reduced artificially, as when one climbs a moun-
tain or ascends in a balloon, one notes the same phenomena as in
fish taken from the water.
The body swells, the inner fluids distend the tissues outwards,
exerting a vigorous pressure on them, burst the vessels, and often
cause hemorrhages.
Rarefied air contains less oxygen in a given volume, so that
respiration, being incomplete, is accelerated to compensate for this
deficiency; the inspirations are proportionately more numerous; the
heart contracts vigorously and more frequently, the blood circulates
with difficulty, the lungs are congested, the blood vessels are dis-
tended, and aneurisms are formed. (P. 9.)
In summary, according to Flemeing, the effect of altitude can
be produced in several ways:
1. By the decrease of the atmospheric pressure: the muscles and
the articulations tend to relax, the blood stops or transudes through
the walls of the vessels, especially the mucous membrane of the air
passages, the lungs, and the brain envelopes.
2. By cutaneous and pulmonary evaporation ....
3. The frequency of the circulation and the respiration is coun-
terbalanced, or better, caused by the small quantities of oxygen which
the inspired air contains.
4. The lowered temperature ....
5. The more powerful rays of the sun ... . which cause irrita-
tion of the eyes, the brain, and the spinal cord. (P. 12.)
M. Bouchard, in his noteworthy thesis .on the pathogeny of
hemorrhages,110 is led to express his opinion about the cause of
the symptoms, noted both in persons subjected to a considerable
282 Historical
decrease of pressure and in workmen who are being decompressed
when they leave the caissons of bridge piers. In his opinion, as
we shall see at the proper time, hemorrhages are due partly to
the escape in the vessels of the carbonic acid of the blood, which
has been stored up there in exaggerated proportions during the
compression.
Decompression by ascent would produce the same effect; and if
hemorrhages have been noted particularly in mountain climbers,
the theory which he suggests may explain the difference in these
effects:
The man who rises in an aerostat performs practically no work
except that required by the respiratory movements. The man who
climbs a lofty mountain, on the contrary, makes a considerable muscu-
lar expenditure and must load his blood with carbonic acid. Is it not,
moreover, to this accumulation of carbonic acid in the blood that
certain authors attribute this peculiar dizzy state called mountain
sickness? (P. 102.)
Errors are hardy. It is strange to note that in spite of the
authoritative answer made by M. Jourdanet to the theory of the
Weber brothers, it continues to be taught almost universally.
M. Beclard,120 in the last edition of a book which should be in
the hands of all students, says, in fact:
When man rises in the air, climbing very high mountains on
foot, as the rarefaction of the air increases, he experiences a very
peculiar feeling. It seems to him that his limbs are heavier; the
lower limbs especially soon become the seat of a fatigue which urges
him to rest. Hardly has he stopped an instant when this fatigue
disappears to reappear after a short time; and so on. This is what
happens; the atmospheric pressure is no longer sufficient by itself to
keep the head of the femur firmly against the cotyloid cavity, and
thus counterbalance the weight of the lower limb, and muscular effort
must keep the limb in its articular relations. This unusual muscular
effort is promptly followed by need of rest for the muscles ....
This effect is felt even when the differences in pressure of the
barometric column are not very great. When the barometer falls,
since the muscles have to move heavier organs, we say that the
weather is heavy, although in reality the pressure exerted upon the
surface of the body by the atmospheric column is less. Likewise,
when the barometer rises, movements are made more easily. (P.
697.)
As to the symptoms of decompression other than heaviness of
the limbs, M. Beclard attributes no importance to them when the
transitions are made rather slowly:
At Potosi (4000 meters), at Deba (5000 meters) .... the functions
of metabolism, respiration, and circulation of the mountain dwellers
Theories and Experiments 283
go on as in dwellers on the plains, and they are in just as good
health ....
Men and animals therefore can endure very considerable varia-
tions in pressure without disturbance of the functions of life. It is
true that, since the density of the air is lessened, the air drawn into
the lungs contains in each inspiration less oxygen than on the plain
in the same volume; but the movements of respiration harmonize
with these new conditions. Moreover, pressure is still exerted in all
directions, the air penetrates all the open cavities (alimentary canal,
respiratory passages), the gases of the blood are put in equilibrium
of tension with the atmospheric air, and the normal conditions of
gaseous exchange are not altered in the lungs.
The variations in the pressure of the atmospheric medium in
mountain ascents or in balloon ascensions are not likely either to
cause painful symptoms in regard to metabolism.
But this is not true when the decompression takes place rapidly,
as happens in aerostatic ascensions:
Then a certain time is needed for the equilibrium between the
inner gases and the outer gases to be established. When the ascen-
sion has been to a considerable altitude, sometimes there appears a
difficulty in breathing, suffocations (from expansion of the intestinal
gases which press upon the lungs, crowding the diaphragm upwards)
and local hemorrhages in the mucous membranes (probably from, sud-
den expansion of the gases contained in the vessels, and from rupture
of the capillaries). (P. 696.)
Beside the ideas of physicians with theories we should place
the opinion expressed by mountain climbers. After the theories
and the discussions which we have just reported, it is somewhat
surprising to see certain travellers almost deny the effect of de-
compression.
For instance, Hudson,1-1 who scorning "the easy beaten path
which usually leads to Mont Blanc," ascended the mountain by a
new route, starting from Saint Gervais, states that:
If one is careful to save his strength, he can cross the highest
summits without experiencing any serious inconvenience. Several
persons have complained of discomfort experienced at great heights,
nausea, drowsiness, bleeding from the nose, the eyes and the ears,
and I do not doubt that such symptoms are possible; but my long
training in mountain journeys has proved to me that they should be
attributed only to fatigue, to which no doubt may be added cold
and the rarity of the air, or rather the unusual precautions required
by these two circumstances. In fact, there were five of us in the
group, and thanks solely to care not to get tired, none of us had an
instant of discomfort; the same thing was true at the time of my
ascent of Monte Rosa. (P. 85.)
Dr. Piachaud,1-2 whose interesting observations we have already
284 Historical
summarized, made during his ascent of Mont Blanc in 1864, also
attributes to fatigue alone the disturbances of circulation and
respiration; according to him, the drowsiness is due to cold, the
muscular fatigue to the cause indicated by Brachet, and the heavi-
ness of the lower muscles to the cause specified by Weber and von
Humboldt.
But these not very original estimations have hardly any im-
portance beside the new and very ingenious theory advanced by
Dr. Lortet.1-3 We have reported at length the observations made
with all the precision required by modern physiological research
by this learned physician during his ascent of Mont Blanc. The
discovery to which he gives most importance is the decrease of
the body temperature during the act of ascent. In his opinion,
this is the true cause of the symptoms experienced, and to explain
it, M. Lortet relies upon the elementary notions of the mechanical
theory of heat:
In a state of rest and fasting, man burns the materials of his
blood, and the heat developed is wholly employed in maintaining his
temperature constant in the midst of atmospheric variations. On the
plain and during moderate mechanical work, the intensity of the
respiratory combustions, as M. Gavarret has shown, increases propor-
tionately to the expenditure of energy. There is a transformation of
heat into mechanical energy, but because of the density of the air
and the quantity of oxygen inspired, there is enough heat formed to
make up for this expenditure.
In the mountains, especially at great altitudes and on very steep
snowy slopes, where the mechanical work of the ascent is great, an
enormous quantity of heat is needed to be transformed into muscular
energy. This expenditure of energy uses up more heat than the or-
ganism can furnish, hence the perceptible chilling of the body and the
frequent halts which must be made so that one can gain warmth.
Although the body is burning hot, although it is often covered with
perspiration, it becomes chilled during the ascent, because it uses up
too much heat and because the respiratory combustion cannot furnish
a sufficient quantity of it because the air lacks density; because of the
rarefaction of the air, at each inspiration less oxygen enters the lungs
at a great height than on the plain. (P. 33.)
M. Lortet then shows, by a simple calculation, that while he is
ascending 1000 meters, a man weighing 75 kilograms would find
that the temperature of his body would drop 2.3°, if he furnished
no restorative heat. Hence he draws this conclusion that the drop
of 4° to 5°, which he noted in ascending to 3800 meters, is quite
natural and within the limits indicated by his theory:
Let us take, for example, a human body weighing 75 kilograms,
and let us assume that during the ascent no combustion repairs the
Theories and Experiments 285
loss of heat undergone; let us assume also that all the mechanical
work is usefully employed, that is, that none of it is lost in slipping,
false steps, etc.
When the body has been raised 1000 meters, the quantity of work
accomplished will be represented by 75 x 1000 or 75,000 kilogram-
meters.
As the mechanical equivalent of heat is 425 kilogram-meters for
each unit of heat, to get the quantity of heat absorbed during this
75,000
work of ascent of 1000 meters, we shall have =176 units of
425
heat. If we assume that the specific heat of the human body is equal
to that of water, that is, equal to 1, and if we represent this specific
heat by C; if we call the drop in body temperature X, we shall have:
quantity of heat lost by the body 75 (C + X) or 176 = 75 x X, whence
176
X = , or X = 2.3
75
Therefore the drop in body temperature resulting from the heat
absorbed by a work of 75,000 kilogram-meters, performed in an ascent
of 1000 meters, would be 2.3° centigrade, assuming that no combustion
repaired, at least in part, this loss of heat. But it is evident that in
reality this combustion exists and that a part of the heat expended
is restored while it is being absorbed. But we have seen, by the
study which we have made of the respiratory and circulatory disturb-
ances, how much this combustion is hampered at a certain altitude,
and how incomplete it is.
Furthermore, it is evident also that all the energy expended is far
from being useful because of false steps and the softness of the snow.
The quantity of heat used must therefore be enormous, and the drop in
temperature must be great and hard to meet by respiratory com-
bustion.
We see then, when these different elements of the problem are
well considered, that this drop of four and some tenths degrees centi-
grade, in the ascent of Mont Blanc, is not at all extraordinary because
this figure gives one and some tenths degrees centigrade for each thou-
sand meters of elevation, a quantity which is very near the 2.3° centi-
grade given us by the physical theory, when we do not take into
account the respiratory combustions. (P. 36.)
However, when one is digesting, there is almost no drop in tem-
perature, probably because of the acceleration of the circulation, either
general or capillary, and perhaps also because of an extremely rapid
absorption of alimentary material. This explains the practical habit of
the guides of giving out food about every two hours. Unfortunately,
above 4500 meters, distaste for food is so great that it is almost im-
possible to swallow a few mouthfuls. (P. 37.)
To this chief cause others are added, which M. Lortet stresses.
First:
The rapidity of the circulation is another cause of the drop in
286 Historical
temperature, since the blood does not have time to become suitably
oxygenated in the pulmonary vesicles. (P. 34.)
In addition, as M. Gavarret has shown:
The creation of mechanical energy corresponding to useful work,
accomplished during the ascent, requires the production of 65 liters of
carbonic acid above the 22 liters of this gas which man forms per hour
in his capillaries to maintain his temperature. The consequences of
the production of so great a quantity of carbonic acid in the body are
apparent.
At a great height, the respiratory and circulatory movements are
accelerated not only to make possible the absorption of an adequate
quantity of oxygen, but also to free the blood of the carbonic acid
which it holds in solution. But this exhalation of gas, though very
active, is not sufficient to. maintain the normal composition of the blood,
which remains supersaturated with carbonic acid; hence the occipital
headache, the nausea, an irresistible drowsiness, and a still greater
drop in temperature, from which travellers and guides usually suffer
above 4000 to 4500 meters. (P. 35.)
And he concludes by saying:
The symptoms known by the name of mountain sickness are due
chiefly to the great chilling of the body, and perhaps also to a cor-
ruption of the blood by carbonic acid. (P. 37.)
M. Lortet was accompanied on his ascent by an English physi-
cian, Dr. W. Marcet,1-4 who made the same experiments, and gave
an account of them in a special work.
The observations were made with a thermometer placed in the
mouth, without pausing in the ascent, because:
The pause in the progress upward, however short its duration, was
nevertheless enough to permit the body to produce heat momentarily
to replace that which had been expended during the act of ascent.
The results which M. W. Marcet reached are identical with
those of M. Lortet:
1. The temperature of the human body in a state of rest does not
seem usually to be less at great heights than at sea level.
2. The temperature of the body invariably tends to drop during
the act of ascent. The amount of this drop depends almost exclusively
upon the time of the last meal. This drop is due to the muscular
movements and not to the effect of rarified air .... A rapid ascent of
only 328 meters was enough to cause a drop of 1.4°.
3. The general discomfort, particularly the nausea, often experi-
enced at great elevations, is accompanied by a considerable drop in
body temperature. It is the result of the fact that the body has be-
come unable, because of the physiological circumstances in which it is
placed, to replace the heat which it has expended during the act of
ascent.
Theories and Experiments 287
And so, according to M. Lortet and M. Marcet, who expresses
himself even more definitely than his travelling companion, there
is a considerable drop in body temperature, and this drop is due
"not to an effect of the rarified air", but to the muscular move-
ment, to the transformation of heat into work.
But these physiologists found in M. Forel an adversary worthy
of them.
The excellent work of the professor of Lausanne is divided into
three parts published, one in 1871, the last two in 1874. It was
undertaken first as a criticism of the memoirs of MM. Marcet and
Lortet. M. Forel 125 begins with very just criticisms of the use of
the buccal thermometer, as an indicator of the real temperature
of the body. I copy here his observations, to the complete accuracy
of which I can testify in many circumstances:
First, it is very difficult to keep the lips hermetically closed for a
sufficient time, and only after a rather large number of attempts and
experiments could I become completely enough accustomed to it so
that I could be sure that not even one bubble of air was admitted
during the experiment. What is difficult in a state of repose becomes
unendurable while one is climbing, when one begins to pant, when all
the openings together are not enough to admit a sufficient quantity of
air into our lungs, especially when the rarefaction of the air demands
imperiously a larger volume than we need on the plain so that our
system may be supplied with enough oxygen; then it is regular torture
to close for ten minutes the mouths which we should like to be able
to enlarge, and the experiment becomes terribly painful.
Another difficulty is to keep the thermometer exactly under the
tongue, and as much as possible always in the same place. The tongue
is very flexible and fairly docile; it can, if need be, surround the bulb
of the thermometer closely enough not to permit contact with the air
of the mouth; but the thing is very difficult, as one can convince him-
self before a mirror, and what is difficult when one is at rest becomes
almost impossible under the painful conditions of the experiment.
Now if any portion of the surface of the bulb is in contact with
the air of the mouth, the results are greatly modified. In fact, the
buccal cavity is not closed at the back, the opening of the palate per-
mits a constant mixture of the air contained in the mouth and the air
which circulates with violent impetuosity in the canal of the pharynx;
even if there is no current of air in the buccal cavity properly so-
called, this mixing necessarily takes place, and in proportions which
are greater, as the current of air in the pharynx is more violent and
the differences of temperature and humidity between the pharyngeal
air and the buccal air are greater. In our conditions of experimenta-
tion on lofty mountains we are as unfavorably placed as possible from
this point of view. The respiration is panting in a very dry and very
cold air. The mixing of air must necessarily increase in amount with
the altitude and with the muscular movements which accelerate the
respiration.
288 Historical
The cold air drawn into the mouth might perhaps be warmed
quickly enough not to cause very considerable changes in temperature:
but as this air is very dry, there is evaporation of a certain quantity of
saliva, and therefore a chilling and a lowering of the temperature.
(P. 12.)
Besides this quite general criticism, M. Forel rightly considers
one of the statements of MM. Lortet and Marcet strange and in-
explicable, unless we admit a serious mistake in the observation:
Both say, in fact, that they had to observe the temperature
while walking, during the very act of ascent, for as soon as they
stopped, or merely slackened the speed of their progress, the ther-
mometer, relatively very low during the ascent, rose almost suddenly
to the normal body temperature ....
Now the human body cannot grow warm so instantaneously. If
the temperature is assumed to be 35°, if the body weighs 60 kilograms,
60 calories must be produced for the temperature to rise to 36° ....
Helmholtz estimates the production of heat of a man weighing 60 kilo-
grams at 1.5 calories per minute; it would therefore take 40 minutes to
produce the 60 calories .... which is very far from the instantaneous-
ness described by Lortet and Marcet. (P. 15.)
The first part of M. Forel's work ends with conclusions from
which I take the two following, which are the most important:
1. The act of ascent normally produces an increase in body tem-
perature of some tenths of a degree;
I reserve my opinion in regard to the effect of ascent upon the
heat production of the body in the condition known by the name of
mountain sickness. (P. 28.) 12"
These conclusions appear again at the end of the second part,
in which physicians and physiologists will read with the greatest
interest experiments investigating very exactly the determination
of the temperature in different parts of the body (hand, armpit,
groin, mouth, auditory canal, urine, rectum) .
The third part is subsequent to the publication in the Annals
of the Natural Sciences of my Memoir, the results of which M.
Forel approves. In it is an anecdote which is very interesting
from the point of view of the theory which I have formulated,
and the accuracy of which the present work will show, I hope, to
those who are the hardest to convince; I shall relate it in the third
part of this work.
Finally, M. Forel ends with a detailed account of an ascent of
Monte Rosa in which he experienced mountain sickness, although
only slightly. On this occasion he makes this remark, — which ex-
plains both certain exaggerations and certain doubts — namely, that
attention given to observation of the symptoms one feels dispels
Theories and Experiments 289
mental depression and lessens fatigue. This is true of danger as
well as of scientific interest; no one suffers from mountain sickness
on dangerous passes.
On this ascent, M. Forel noted that his temperature was always
increased by walking, even above 4000 meters; he himself is sur-
prised at that, considering the very pronounced state of anoxemia
in which he must have been. But as he was not seriously af-
fected, he merely states the fact, and, true to his prudent method,
still reserves the case of ascent during an established state of
mountain sickness.
These conclusions were corroborated by the researches of an
English physiologist who did much research on variations in tem-
perature of the body in health and in sickness.
Cliff ord-Allbutt 127 made a series of ascents, one of them on Mont
Blanc in very bad weather, to study the effects of walking and
climbing on the temperature of the body. It was measured under
the tongue during the act of walking, the maximum thermometer
remaining in place for 15 or 20 minutes.
From his observations he draws the conclusion that muscular
exercise tends to raise the temperature.
I copy one of his tables, the most interesting one, since it re-
lates to the passage from the Grands-Mulets to Mont Blanc:
August 18, 1870.
1:30 in the morning. At the Grands-Mulets, before rising 97.5°F.
3:30 in the morning. Ascent begun at 3 o'clock 97.7
5:00 in the morning. On the Grand-Plateau. Terrible weather 98.0
7:30 in the morning. I began to descend at 7 o'clock 98.5
8:30 in the morning. Arriving at the Grands-Mulets 98.5
9:15 in the morning. At the hotel in Chamounix, in bed 97.6
I should note, however, that the day before, when he reached
the Grands-Mulets, his temperature suddenly dropped to 95.5°, and
rose to 98.5° after a 10 minute rest. August 20, at Chamounix, in
bed, Allbutt's temperature was 95.4°.
Another English physiologist, C. Handfield Jones,128 attributed
the sphygmographic records of M. Lortet to exhaustion from fa-
tigue.
The discussions between MM. Lortet and Forel again attracted
the attention of physicians and physiologists to mountain sickness,
especially in Switzerland. And so M. Dufour,129 in his turn, sug-
gests in regard to this difficult subject a very noteworthy theory,
which shows thorough acquaintance with the recent advances of
science.
290 Historical
In the session of the Diablerets section of the Swiss Alpine
Club, on January 27, he expressed the idea
That the somewhat undefined unhealthy state called mountain sick-
ness results from the absence in the blood of the ternary elements
which are used in combustion. (P. 72.)
M. Dufour is especially struck by the contrast between travel-
lers and aeronauts, since the latter are in good condition at eleva-
tions which the former cannot reach without serious symptoms:
If the mere rarefaction of the air were injurious to health, how
much more seriously affected Glaisher and Coxwell should have been,
who in 25 minutes rose from about sea level to the level of the summit
of Mont Blanc!
Besides, when aeronauts finally experience pathological symptoms,
these symptoms do not at all resemble those of mountain sickness.
M. Glaisher gives a description which resembles a paralysis of sensi-
tivity and movement extending regularly from the extremities to the
center. Is this paralysis produced by a stoppage or a slackening of
the circulation, or is it a direct effect upon innervation? We cannot
tell. The fact that M. Coxwell's hands were blue for a moment seems
to support the first hypothesis, whereas the fact that M. Glaisher lost
the use of the retina, while his mental powers were still intact, would
rather support the second.
At any rate, and this is the point which is important to us, the
pathological symptoms come very late, and when they do come, they
are not the symptoms of mountain sickness.
We are therefore led to consider muscular work as the principal
factor in the production of mountain sickness, and if the rarefaction of
the air makes some contribution to it, it is through the combustion
which the work requires. (P. 76.)
M. Dufour thinks that inanition produced by work is the prin-
cipal cause of mountain sickness. He says that he experienced the
symptoms of it on the plain after great muscular efforts:
M. Dufour experienced several symptoms of mountain sickness,
including nausea, when he was mounting from the bottom of the
mines of Freiberg in a shaft and by vertical ladders. He had walked
in the mine for about three hours, and had eaten nothing; the distress
attacked him while he was ascending, and was still 50 or 60 meters
below the surface of the ground. In covering this short vertical dis-
tance, he had to rest two or three times.
Likewise in an ascent of Pilate, after too rapid a walk from
Hergiswyl, he was seized by extreme prostration, throbbing in the
neck, headache, and dyspnea. At that moment, feeling mechanically
in the pocket of his coat, he found a morsel of bread which he put
into his mouth. After taking five minutes to get enough saliva to
moisten his bread, he swallowed it. A few minutes afterwards, the
symptoms of distress disappeared as if by magic, and he was able to
ascend very easily the remaining 100 or 200 meters. (P. 76.)
Theories and Experiments 291
Then basing his conclusion on recent physiological data, he con-
sidered that the work of ascent uses up the reserve of ternary
materials contained in the blood and the tissues, and results in the
muscular exhaustion.
I shall quote this noteworthy passage verbatim:
It is probable that during the first hours of the ascent, the muscu-
lar work consumes the non-nitrogenous substances immediately avail-
able either in the muscular substance or in the blood.
What replacement can compensate for the effect of so great an
expenditure? It can take place in only two ways: either the chylif-
erous vessels bring into the circulatory stream new elements supplied
by the digestion, or the organism absorbs and draws again into the
circulation the elements of the subcutaneous adipose tissue. This last
point is so certain that working hard and eating little is a means of
getting thin that is well known to everybody. The first of these re-
placements can be made quite quickly; the second, if we judge by the
phenomena of absorption which we often witness, can take place only
much more slowly.
It is probable that the absorption of the adipose tissue to be used
as a combustible in the work of ascent is a phenomenon too slow to
compensate satisfactorily for the expenditure caused by the work of
someone ascending without stopping.
Therefore a moment must come whea, if the climber does not eat,
the available combustible material keeps diminishing and can be only
partly replaced by absorption. This effect will be produced most
easily when after work of several hours the climber approaches a steep
grade which he wishes to climb too quickly, so that there is a still
greater disproportion between the work performed and the time used
in performing it. (P. 77.)
Therefore, according to M. Dufour, it is very easy to explain:
a. The importance of rest, because during rest there is no ex-
penditure whereas replacement continues.
b. The fact that after rest, the quantity of work easily performed
is obviously proportional to the duration of the rest; for the same
reason as above.
c. The fact that, to anyone who has mountain sickness, any new
effort, such as stooping or using the arms, becomes painful. (See
H.-B. de Saussure.)
d. The fact that mountain sickness seems to attack plump persons
more than thin persons, because the former produce, on an equal
ascent, a much larger number of kilogram-meters of work. The fact
that they have in the adipose tissue a deposit of combustible material
is without importance here, for very thin persons always have a suffi-
cient adipose membrane to supply the work of ascent as it generally
appears.
f. Finally, the fact that a means of avoiding mountain sickness is
to eat often, that is, to furnish materials not by way of resorption, but
by way of digestion and absorption. (P. 78.)
292 Historical
Then he draws from his theory this logical conclusion:
We are therefore led to seek a combustible food easy to digest and
absorb, to avoid mountain sickness.
M. Dufour thinks that sugar syrup or better, glucose syrup would
fulfill these conditions. In fact, the fats, which are the best combusti-
ble material, require a certain time for digestion and may not be
digested in time to satisfy an immediate need; the feculae must be
transformed into sugar, glucose syrup then would be the food which
would reach the circulation most easily. (P. 78.)
The discussion aroused by the important theory presented by
M. Dufour brought a very interesting communication from M.
Javelle,130 president of the Diablerets section of the Swiss Alpine
Club.
The narratives which it contains show, as we have already
noted, that persons attacked by mountain sickness, even very seri-
ously, often find that their illness disappears immediately when
dangers appear or when a very intense application of mind be-
comes necessary.
They prove besides that these illnesses are much more frequent
than is generally supposed, and make a satisfactory reply to cer-
tain skeptics who did not hesitate to jeer at what they call the
exaggerations of M. de Saussure.
Let us note that M. Javelle has had great experience on high
peaks, and that he has made nearly 200 ascents of 5000 to 15,000
feet, very often in the company of 10 to 20 young men:
Mountain sickness very frequently appears in the medium region
of the Alps, between 5000 and 10,000 feet, that is, at an elevation where
the air is sufficient for the needs of respiration, and where one can
hardly consider intoxication from excess carbonic acid as an explana-
tion for it. At 14,000 or 15,000 feet, the illness experienced by even
the sturdiest mountaineers differs in several characteristics.
Mountain sickness affects particularly persons who are unaccus-
tomed to the mountains, and especially those who lead a sedentary
life. Those who are anemic rarely escape it. Novices who begin with
a difficult ascent are very likely to pay tribute to it. (P. 136.)
This illness appears especially on soft snow, turf, slopes covered
with landslides where walking is difficult, in small valleys and on long
slopes, in general, everywhere that walking is both tiresome and
monotonous.
It very rarely appears during the climbing of cliffs or on ridges,
very rarely too on difficult or dangerous expeditions.
An interesting conversation or merely a careful observation of the
landscape often wards it off.
M. Javelle has noted that young men who made the expeditions
without interest or rivalry and merely to accompany their companions
were most often affected by it. (P. 13.)
Theories and Experiments 293
The editor of the Bulletin summarizes the discussions which
arose about the etiology of mountain sickness among the members
of the Swiss Alpine Club in this odd sentence:
The principal factors are need of food, the intensity and rapidity
of the work, and the mental characteristics. We cannot remove com-
pletely from the list of causes the rarefaction of the air and intoxica-
tion by carbonic acid. The question, which has a certain interest,
therefore still offers some unknown quantities to be found. (P. 140.)
Moreover, the following passage, taken from the celebrated
physicist and daring mountain climber Tyndall, also gives inter-
esting information on this subject:
It is not a good idea to begin these ascents without having eaten
and it is not good to eat heartily. One must eat a little here and
there, as the need appears. But left to itself, the stomach inevitably
falls ill, and the energy of the system is rapidly exhausted. If the
illness brings on distaste for food, vomiting may ensue and the stomach
be conquered. A little food is enough to restore it. The strongest
guides and the sturdiest porters are sometimes reduced to this ex-
tremity. "Sie mussen sich zwingen". The guides attribute these ca-
prices of the stomach to the great elevation of the air. Perhaps that
is one of the causes, but I am inclined to think that something is
likewise due to movement,— the continuous action of the muscles on
the diaphragm. The conditions under which the journey is made and
those which have preceded it also deserve much attention. One sleeps
little or not at all; the morning meal is taken at an unusual hour;
and if the start is to be made from a cave or a hut instead of a hotel
bed, there is a serious aggravation of bad conditions. It cannot be the
slight difference in height between Mont Blanc and Monte Rosa that
makes the effects of their ascents so different. It is because, for the
first, one makes his coffee of the melted snow of the Grands-Mulets,
and has a bare plank for his bed; whereas for the other, he enjoys
the inn of the Riffel, very comfortable in comparison. Milk and a
crust of bread are all I need to sustain my strength and ward off
mountain sickness. (P. 304.)
These very wise remarks have been made by many travellers.
The degree of fatigue preceding the ascent is an element the im-
portance of which is well known today. The same thing is true
of the habit of walking and of living in the mountains. The fol-
lowing observations of M. Durier 132 in this regard deserve our
approval. We have told earlier how, by a strange coincidence,
M. Durier and his companions, who suffered no ill effects from the
decompression, ascended Mont Blanc just behind MM. Lortet and
Marcet, whose symptoms we have given. M. Durier explains this
difference in the following words:
In general, the physiologists who have studied the effects of moun-
tain sickness upon themselves tear themselves from work in their labo-
294 Historical
ratory and rush to Chamounix; on the first favorable day, they attempt
the ascent. Well! I think that they are making their experiment under
conditions which are not very scientific. The ascent of Mont Blanc is,
after all, very difficult. It requires previous exercise and training.
These scholars are likely to confuse the effects of unusual fatigue which
finds their muscles unprepared, with those of a rarefied atmosphere.
(P. 63.) ....
It is under these conditions that MM. Marcet of Geneva and Lortet
of Lyons made their ascent .... We were in the fourth week of a
journey on foot, during which, without resting even one day, we had
crossed some of the highest passes of the Alps. (P. 66.)
Finally M. Russell Killough,133 whose very astute replies to the
skeptics who deny mountain sickness I have mentioned, is less for-
tunate in regard to theoretical explanations. He revives, without
the slightest proof to support him, either from experiments or rea-
soning, the hypothesis of the injurious effect of snow:
I am ready to agree that altitude is not exclusively the cause of
these sufferings. I think, and others have thought before me, that snow
is an important factor in the question, because as soon as one touches
terra firma, he is relieved. Have we not all observed that on glaciers
the air has a metallic taste, like water from melted snow, that it seems
polluted, as if the ice and snow poisoned it with their emanations?
Why in the tropics, where one walks on grass at an altitude of 18,000
feet, are nausea and the desire to sleep, this sort of somnambulism,
felt only at much greater heights than in Europe?
At any rate, whatever the cause may be, this peculiar sickness
cannot be denied, and man cannot live at certain altitudes any more
than in the depths of the ocean. (P. 244.)
If we pass from the Alps to the Himalayas, we see modern
travellers giving us in their narratives testimony that even in our
days the sicknesses of great elevations are attributed by the natives
to the influence of plants which are supposed to poison the air from
a distance.
Mistress Hervey 134 refers to it repeatedly:
These extraordinary attacks on passes of great altitude are at-
tributed by the natives to what they call Bischk-Ke-Hawa (Bischk,
poison; Hawa, wind) or poisoned wind. They believe that the wind
becomes poisoned because it blows over certain plants of the group
of mosses, which grow abundantly on the high mountains of Tartary,
and are found where vegetation ceases. From the summit of Bara
Lacha to Yunnumscutchoo, I saw thousands of them. They have very
small yellow flowers, and are of different species. A more scientific
explanation of this peculiar illness attributes it to the great rarity of
the air at these extreme altitudes. (Vol. I, p. 133.)
We even see, in several parts of her narrative, and we have
quoted some very strange ones in this connection, that she is not
Theories and Experiments 295
always very sure of the superiority of ''the more scientific ex-
planation".
Henderson 135 also speaks of plants; only it is not a kind of
moss, but an artemisia:
Before reaching camp, many of our followers complained of head-
ache, and I found several of the Thibetan shepherds lying by the road,
in a state of complete prostration. When I asked them what was the
matter, they placed one hand on their foreheads, and with the other
tore up a piece of a strong-smelling artemisia, making signs that this
plant was the cause of their sufferings. On several of the passes, this
artemisia has an extremely powerful odor, and all the baggage, the
horses and the men coming from Yarkand are tainted with it. Even
mutton has this odor.
Drew 1:;" does not limit himself to mentioning this prejudice
and refuting it authoritatively, he looks at the question itself, and
does not inquire why one is sick, which seems to him very simple,
but how one can resist the dangerous effect of expanded air:
In the valleys of Rupsku, water boils at about 187°' F., which
corresponds to a barometric elevation of 17.8 inches; so that the quan-
tity of air — and oxygen — drawn into our lungs by an ordinary inspira-
tion is only 7/12 of the amount that enters at sea level. How do the
Champas (tribes which occupy the high plains of Rupsku, to the south-
east) compensate for this loss? I cannot tell exactly; I think, first,
that there is less wear and tear on the tissues in their bodies than in
the tribes which live in lower and warmer regions; they take less
muscular exercise than the peoples of the surrounding lands; it is true
that they are good walkers, but they think little of this quality and do
not wish to carry burdens. Watching over flocks is not an occupation
which causes the muscles to act vigorously. But that cannot explain
everything; there must be some compensating habit which makes them
capable of absorbing a large volume of this rarified air; probably, with-
out realizing it, they breathe more deeply.
In us, this oxygen compensation tends to take place by a simple
and direct means. Respiration becomes more rapid and more deep;
there is an effort to increase both the number of inspirations and the
capacity of each of them. The intensity of this effect increases every
time one mounts a little when one is already above the level where
ordinary respiration is sufficient. (P. 290.)
The natives commonly attribute these harmful effects of rarified air
to plants which, in their opinion, have the power of poisoning the air.
Some of the plants which grow at high altitudes exhale an odor when
they are crushed, and it is to them that the discomforts are attributed.
The onion, so much abused, which grows wild at great heights, is often
blamed. But an easy reply to this error is that the effects are most
marked at elevations where these plants, and all other vegetation have
disappeared. (P. 292.)
296 Historical
These ideas are far more definite and certain than those of
Captain Burton 137 about the origin of mountain sickness:
Some tried to explain our immunity to mountain sickness or the
puna on the Grand-Pic, by the existence of a wind blowing violently
and steadily from the east, which brought to our lungs the quantity of
oxygen necessary for their consumption. I think, however, that this
sickness must be, like seasickness, a disorder of the liver or the stom-
ach, often aggravated by stimulants and by violent and sudden exer-
cise. (Vol. II, p. 121.)
The celebrated African traveller quotes seriously in this con-
nection a passage from a work which I could not procure, which
contains, I think, one of the most comical ideas ever expressed on
this difficult subject:
According to Dr. J. Hunt (Acclimatisation of Man) Europeans
cannot live long at a great elevation in the northern hemisphere; the
natives of the south can .... "This difference between the north and
the south hemisphere, he says, is caused by the difference of the attrac-
tion to the North Pole. In the northern hemisphere the ascent of a
high mountain causes a rush of blood to the head; in the southern, it
is attracted to the feet: and hence the cause of the discomforts ex-
perienced in the ascent of a mountain in the first hemisphere."
I shall end this long series of quotations by reporting almost
entirely two very interesting accounts, which we owe to the pens
of very distinguished physicians, and in which there is a discus-
sion of the effects of altitudes insufficient to produce mountain
sickness, but sufficient to cause physiological changes which have
proved useful to therapeutics.
The first is by Dr. Jaccoud,138 and is devoted to the study, from
the medical standpoint, of the spa of Saint Moritz, in the Upper
Engadine.
The greatest variations of the barometer at the baths are in-
cluded between 599 and 627 millimeters. The altitude of the vil-
lage of Saint Moritz is 1855 meters above sea level. On the vast
plateau of the Engadine the climate is much more clement than
at corresponding elevations in the rest of Switzerland.
In the adult who is in good health, the first effects of altitude are
shown by an increase of appetite noticeable the first day, which keeps
equal with a proportional increase of digestive and assimilative
power ....
The parallel superactivity of the digestive functions and of metab-
olism is shown, on the one hand, by the ease and speed of digestion,
in spite of the increase of the ingesta; on the other hand, by changes
in proportion between the adipose tissue and the muscular tissue. . The
first decreases considerably as a result of a prolonged sojourn in the
Theories and Experiments 297
Upper Engadine, whereas the muscles gain a preponderant develop-
ment shown by increase of strength and motor capacity ....
The decrease of the atmospheric pressure causes the acceleration
of the heart beats; in myself, I noted an increase varying from 12 to
18 in the number of radial pulsations; moreover, the circulation in
general is considerably modified, in that there is a strong flow of blood
to the periphery; the cutaneous capillaries are turgescent, and the tegu-
ments take on a violet red color found in the upper mucous mem-
branes, especially those of the mouth and tongue; if the sojourn con-
tinues for several weeks, the predominance of the peripheral circu-
lation produces a deeper pigmentation of the skin; as this phenomenon
is more marked in regions usually exposed to the action of the sun,
one might think that this is merely a pigmentation by solar irradia-
tion; but the same modification occurs on parts protected by clothing,
and its real cause is thereby clearly demonstrated. In a few cases,
rarer than one would suppose a priori, instances of slight epistaxis also
show the change in the distribution of the blood.
The constant rush of blood to the periphery keeps the viscera in
a state of relative anemia, which, in proportion to its degree, is re-
vealed only by favorable phenomena; the cerebro-spinal functions are
more active and easy, .the head is free and light, the locomotor power
is increased, respiration is noticeably eased, although its mode is greatly
changed, as we shall see in an instant. These organic changes awaken
in the person who undergoes them the feeling of new strength, which
he judges by comparison with his usual condition; he feels well and
gay, he has a vim justified by the real increase of his capacity for
physical work. (P. 31.)
The rarefaction of the air at the altitude of Saint Moritz produces
in the respiratory function two changes which are the point of de-
parture of important modifications. The frequency of the respiration
is increased, the average number of my inspirations in Paris, at rest,
is 15 per minute; it is 19 to 20 in the Engadine; while it is more
frequent, the respiration is deeper, or rather, more ample; the reason
is that in this rarified medium a greater capacity and inspiratory ab-
sorption are needed to maintain in the pulmonary apparatus the quan-
tity of air necessary for the regular execution of the operations of
hematosis and metabolism in a state of superactivity. The slight in-
crease in the number of inspirations could not produce this result; it
can come only from a greater pulmonary expansion, which puts to
work certain regions of the lungs which I call lazy, because, under
ordinary conditions, they take only a very slight part in the inspira-
tory expansion; these regions are the upper parts of the organs. But
since the atmospheric pressure is lowered, this more complete partici-
pation of the lungs in the inspiratory act necessarily involves an in-
crease in action of the muscular forces which control the expansion of
the thorax; and this combination of subordinate conditions, all pro-
duced by the change in pressure of the respirable medium, results
finally in systematic and constant gymnastics of the respiratory appa-
ratus, which are kept up without fatigue at the maximum of func-
tional activity.
And thus, by active intervention of the organs of respiration, there
298 Historical
are produced effects analogous to those which they undergo passively
under the influence of compressed air; in rarified air, the inspiratory
absorption becomes complete by means of active use of muscular pow-
ers; in compressed air, the increased inspiratory absorption is the result
of an increased pressure, to which the lungs, and the lungs alone, yield
passively. This comparison, which seems to me interesting, sufficiently
establishes the superiority of the first condition, in regard to the de-
velopment and regular exercise of the pulmonary functions. (P. 34.)
And so increase in the number and amplitude of the respiratory
movements, with the purpose of compensating for the oxygen defi-
cit due to the decreased weight of the air, the acceleration of the
heart beats, and the rush of blood to the periphery of the body
are, in M. Jaccoud's opinion, the effects on the organism of a
decompression of 15 to 16 centimeters.
Dr. Armieux,139 of whom I still have to speak, examined care-
fully the soldiers under his medical care at the thermal spa of
Bareges (1270 meters) .
He begins by calculating the decrease in the weight of the air
sustained by a man's body at the elevation of Bareges; it is
about 220 kilograms; "this decrease," he says, "is very perceptible;
one is more agile and vigorous (p. 7)".
Finally, at Bareges, considering the density of the air, there is
a deficit in the quantity of oxygen admitted to the lungs of 22.56
grams per hour and 541.44 grams per day.
But here is the really original part of the work of M. Armieux:
May 4, 1867, at Toulouse, I measured the chests of 90 hospital
attendants, who were to be sent to Bareges. The chest circumference,
taken horizontally at the level of the nipples, gave me an average of
871 millimeters, at rest, and 905 millimeters in the greatest amplitude
obtained by a deep inspiration.
These men reached Bareges May 15, they did not take the thermal
cure, and the subsequent observations showed only the effect of the
hygienic medium.
June 27, that is, after 43 days of residence, their chests measured
again gave averages of 888 millimeters in circumference at rest and
917 millimeters in the maximum expansion; the increase of circum-
ference then was on the average, in the first case, 17 millimeters, in
the second 12 millimeters.
September 17, after a sojourn of four months at Bareges, the same
subjects, given a new measurement, furnished the following average
results: 900 millimeters at rest and 930 millimeters in maximum ex-
pansion; there was a new average increase of 12 or 13 millimeters over
the measurements of the month of June, and a total progressive in-
crease, after four months, of 25 millimeters in expansion, and 32.9
millimeters at rest.
It is therefore indisputable that the chests of these soldiers in-
Theories and Experiments
299
creased in capacity, in four months, in a rather large proportion, as a
result of their removal to a place the altitude of which is 1100 meters
higher than that in which they had formerly lived . . . .
To get a more direct proof, in 1868, we made an experiment which
confirmed the former one, taking care to get the exact weight of the
subjects so as to compare their total material gain with the increase
in volume of the chest.
We also wished this time to keep an account of the changes made
in the pulse rate and the respiratory movements by removal to high
altitudes.
We subjected fourteen hospital attendants to a close observation,
before their departure for Bareges and after thirty-five days of resi-
dence there.
The following table gives the details and the averages of our
observations:
Toulouse
Bareges
May 7, 1868
1
June 18,
1868
Height
Weight
. 1
1 1
Weight
1
Age j meters
kilos
Chest |Pulse
Res.
kilos
| Chest
Pulse
Res.
22
1.620
62.100
91c.
86
20
64.5
98
85
19
23
1.590
62
86
76
16
61
87
80
20
19
1.567
56
80
70
17
57
82 j 64
20
23
1.620
63.100
85
80
18
65
88
70
22
31
1.650
63
88
74
17
64
90
68
20
19
1.615
52
76
72
18
56.5
81
75
21
23
1.680
64
86
80
20
67
89
70
22
23
1.630
60
89 82
21
61
89
80
22
23
1.610
59.9
86 J 90
18
60
86
88
22
24
1.600
60
84 1 75
20
59.5
88
65
20
20
1.610
57
85 1 74
18
58
86
70
19
49
1.640
59.5
81 72
19
59.7
83
68
20
23
1.585
64
90 80
18
66.5
91
80
20
36
1.610
59
86 80
21
60
1
89
74
23
Totals _
841.6
1191 |1091 |261
859.7
1227 |io:
290
Average
60.114 |
85.70|77.92 |18.64
61.4
87.64
74.07
20.70
Av. at Bareges
61.400
87.64j74.07 |20.70
|
Av. at Toulouse
Inc. at Bareges
60.114 ]
85.70|77.92 J18.64
1.286 |
1.94
— | 2.06
Dec. at Bareges
— |
—
3.85 | —
1
We see by this table that the increase in weight is, on the average,
1 kilogram and 286 grams, varying from 1 to 4 kilograms in 12 of these
soldiers, and showing a slight decrease in two of them, whereas the
increase in the volume of the chest is, on the average, nearly two
centimeters, which is relatively greater; this increase went as high as
7 centimeters in the first subject; finally, it is general and exists even
in those who lost weight, which is decisive.
300 Historical
For the sake of completeness, I copy here a passage which
concerns the composition of the gases of the blood, although it
contains unexplainable mistakes, and although I understand nei-
ther its purpose nor its results; but it is interesting to show by
a very recent example how many unknown quantities and obscuri-
ties these questions contain, even in the minds of the most learned
physicians:
Besides the phenomena which we have just reported, there are
produced as a result of the decrease of atmospheric pressure an expan-
sion and a greater tension of the gases contained in the blood vessels.
The venous blood contains per liter:
Oxygen 11 cubic centimeters
Nitrogen 15 cubic centimeters
Carbonic acid 55 cubic centimeters
Total 81 cubic centimeters
The arterial blood contains per liter:
Oxygen 24 cubic centimeters
Nitrogen 13 cubic centimeters
Carbonic acid 64 cubic centimeters
Total 101 cubic centimeters
For M. Schoeuffele who studied the question at Bareges, these fig-
ures become at the pressure of 65 centimeters: 94.780 for the venous
blood and 119.640 for the arterial blood; the increase in volume of the
intra-vascular gas would therefore be on the average 11.25% at the
altitude of Bareges.
M. Armieux ends his work with the following conclusions:
The experiments which I have just reported show that persons
who go to Bareges experience, as effects of the altitude:
1. A considerable increase of the thoracic capacity to compensate
for the oxygen deficit;
2. An increase in weight, which shows greater metabolic activity;
3. An increase of respiratory movements;
4. A decrease in the pulse rate;
5. A lack of correlation between the two relations of the respira-
tion and the circulation;
6. An expansion of the gases contained physiologically in the
blood vessels, as a result of decreased atmospheric pressure;
7. A greater tendency toward diaphoresis for the same reason.
This considerable increase of the thoracic capacity, observed by
M. Armieux in soldiers subjected continuously to the influence of
low barometric pressure recalls what was said long before by
Theories and Experiments 301
d'Orbigny,140 in speaking of a Peruvian tribe, the Quichuas, who
live in the lofty regions of the Cordillera:
Their bodies are more bulky in the Quichuas than in the other
nations of the mountains; we can describe them as characteristic. The
Quichuas have very broad and square shoulders, their chests are ex-
tremely capacious, very bulging, and longer than usual, which makes
the trunk larger; the normal ratio of respective length of the trunk
with the extremities does not seem to be the same in the Quichuas
as in our European races, and differs equally from that of the other
American branches. (Vol. I, p. 226.)
And the celebrated traveller, struck at the same time by this
thoracic amplitude, the habitat of this tribe, and its immunity to
the soroche, tries to determine the anatomical fact and to connect
it theoretically with the conditions of life of these Indians.
Let us return to the causes which produce in the Quichuas the
great volume we have observed: many researches have made us
attribute it to the influence of the lofty regions in which they live
and to the modifications resulting from the extreme expansion of the
air. The plateaux on which they dwell are always included between
the limits of 7500 to 15,000 feet, or from 2500 to 5000 meters above
sea level; the air there is so rarified that a greater quantity is re-
quired than at sea level for man to find the elements of life in it.
Since the lungs need, because of the great volume necessary and their
greater expansion during the inspiration, a larger cavity than in the
lowlands, from infancy and during the whole period of growth, this
cavity receives a great development, quite independent of that of the
other parts.
We wished to ascertain whether, as we should have assumed
a priori, the lungs themselves had not undergone considerable modi-
fications, as a result of their greater tension. Living in the city of
La Paz, which is 3717 meters above sea level, and learning that at
the hospital there were always Indians from very populous plateaux
of still greater elevation (3900 to 4400 meters), we took advantage of
the kindness of our compatriot M. Bernier, physician of this hospital;
we asked him to permit us to make the autopsy of the cadavers of
some of these Indians of the higher regions, and, as we expected,
we found with him that the lungs had extraordinary dimensions, as
the outer form of the chest indicated. (M. Burnier showed us, be-
sides, that the lungs seemed to be divided into cells much more num-
erous than usual. Since this fact seemed to us strange and hard to
believe, we asked M. Burnier to repeat these observations on a larger
number of subjects; and when, after a few years, we saw this well
informed physician again, he confirmed it once more completely.) We
noted that the cells are larger than those of the lungs which we had
dissected in France; a condition which was necessary to increase the
surface in contact with the ambient atmosphere. In summary, we dis-
covered: 1. that the cells are more expanded; 2. that their expan-
sion increases considerably the volume of the lungs; 3. that conse-
302 Historical
quently the lungs need a larger cavity to contain them; 4. that there-
fore the chest has a greater capacity than in the normal condition;
5. that this great development of the chest lengthens the trunk a
little beyond the ordinary proportions, almost out of harmony with the
length of the extremities, which have remained as they would have
been, if the chest had retained its natural dimensions. (Vol. I, p. 267.)
Thse anatomical observations are so interesting that the Society
of Anthropology discussed them among the Ethnological and Medi-
cal Questions Relating to Peru, and suggested in 1861 that travel-
lers verify them.
In a scholarly report, M. Gosse senior,141 states that "up to the
present, the assertions of d'Orbigny have not been verified by any
traveller" (p. 107). He even mentions a fact which would seem
to prove that this is a racial characteristic independent of the
environment, since:
The descendants of the mountaineers settled in a colony by the
Incas on the seashore near Cobija would have retained up to the pres-
ent, as an effect of heredity, the special physical constitution, said to
have been acquired in the atmosphere of the lofty plateaux. (P. 108.)
The same, year, M. Jourdanet,142 speaking of the Indians of
Mexico, said:
The Indian, whom we may consider as positively acclimated, has a
chest the amplitude of which exceeds the proportions which we should
expect from his short stature. And so he performs work which might
well surprise, us in any country .... His vast chest makes him com-
fortable in the midst of this thin air. (P. 98.)
On this point also he was contradicted by Coindet.143 Accord-
ing to this observer, for a series of Frenchmen whose average
height was 1.678 meters, the thoracic circumference on the level
of the nipples was 92.450 centimeters, whereas in the Mexicans,
in an average height of 1.620 meters, it fell to 89.048 centimeters.
But the English traveller Forbes confirmed the observations of
d'Orbigny and M. Jourdanet:
M. D. Forbes, says M. Darwin,144 who carefully measured a great
number of Aymaras, living at an altitude included between 10,000 and
15,000 feet, told me that they differ very greatly from the men of all
other races he has seen in the circumference and the length of their
bodies.
Finally, in his last book, M. Jourdanet 145 gives specific data,
saying:
I have the abstract of a great number of observations which do
not admit the least doubt. They justify me in stating that with an
average height of 160 to 165 centimeters, the Indians of Anahuac have
Theories and Experiments 303
a sternum 227 mm. long, with a thoracic circumference of 895 mm.,
measured immediately above the nipples.
On the other hand, my researches permit me to state in a general
way that to find the same chest dimensions in the Creoles, the height
had to increase from 168 to 173 centimeters. (Vol. I, p. 317.)
So the point is really not so much an unusually large thoracic
capacity as a shorter height, or, to speak more exactly, lower
limbs which are shorter in proportion to the height of the trunk.
But let us return to the inquiries of Dr. Gosse.
M. Gosse follows his shrewd observations on this interesting
point by a questionnaire on mountain sickness, which I think it
best to quote here verbatim:
The study of the influence exerted by the rarefied air of high
altitudes in the Peruvian Andes upon the physiological constitution of
their inhabitants naturally leads us to the study of symptoms produced
by this cause in persons foreign to the plateaux, who are exposed to
it imprudently or too suddenly, and of the measures which are used
to combat the symptoms or at least to moderate their effects.
If the symptoms observed in our European Alps, to which the
name of mountain sickness has been given, are limited in general to
extreme breathlessness, accompanied by headache, throbbing of the
carotids, palpitations, nausea, disturbance of the digestive functions,
great lassitude and sometimes syncope, the symptoms appearing in the
Andes of Peru, known by the names of soroche, mareo, or veta, reached
such violence, they say, that they deserve the attention of physicians
who are explorers, all the more because sufficient analysis has not yet
been made, in this connection, of the mechanism of the action, usually
combined, of the decrease of the oxygen in the air and of the atmos-
pheric pressure, of the eventual drop in temperature caused by easier
radiation of heat, of the absence of humidity, and especially of the
unnatural strain on the muscles, and because, as explanation of the
anomalies, there has been a tendency to suspect the existence in Peru
of special unknown causes, which would not be found elsewhere.
Observations carefully made and new records thoroughly verified
would end doubts and reconcile opinions. With this purpose we are
propounding the following questions:
1. What are the characteristic symptoms of the soroche of the
Peruvian Andes, with reference to the nervous, circulatory, pulmonary,
or muscular systems?
2. What is the normal sequence of these symptoms, in the com-
monest cases, and which are the predominating ones?
3. Are there premonitory symptoms of the acute attack, and what
are they?
4. Is a tendency to nasal, labial, pulmonary, ocular, cutaneous,
etc., hemorrhages noted frequently at very great elevations?
5. Are a congested condition of the cornea and erythema of the
face observed, in the absence of reflected light from the snow?
6. Does the skin take on a livid or cyanosed shade at an eleva-
304 Historical
tion which cannot be less than 3800 meters, but which, in the latitude
of Peru, must be the line of perpetual snow? If this phenomenon
appears, is it only temporary during the ascent, or does it persist after
the summit has been reached?
7. When the dwellers on the heights descend to the plains and
toward sea level, do they experience a disturbance in their functions,
and of what does this disturbance consist?
8. Is a mental disturbance corresponding to the physical disturb-
ance, or discouragement, or irritability of temper often observed?
9. Are the symptoms of the soroche the same on the eastern and
western slopes of the Andes, whatever the exposure of the places where
they are observed?
10. Do they occur only at the line of eternal snow, as certain
authors maintain, or do the Peruvian and Bolivian Andes furnish veri-
fied exceptions to this rule?
11. Do strangers to the plateaux of the Andes experience the
soroche when they reach high elevations on the Cordillera on horse-
back? And when they feel the attacks, did muscular efforts usually
precede the disturbance of the organs of circulation and respiration?
12. Do the effects of the soroche differ with age and sex?
13. Do they vary with idiosyncrasies, and what are the idiosyn-
crasies which predispose to it or retard it?
14. What is the effect exerted upon its production or its symptoms
by the seasons, the prevailing winds, or storms?
15. What is the effect of the cold in the places where the soroche
appears? Specify the average temperature of these places and the
absolute temperature at the time the symptoms appeared.
16. What is the effect of dryness or humidity?
17. Is it proved that the absolute altitude in the atmosphere is
not enough to explain certain local anomalies? And if this is an actual
fact, seek out the probable causes of these anomalies, either in the
atmospheric conditions of the time or the locality, or in the telluric
conditions, especially in the nature of emanations which may rise from
the ground. Study in this connection the conformation of these lo-
calities which might favor the continued presence of water and atmos-
pheric humidity, their nearness to ore-bearing regions, which might
exhale mineral, harmful, arsenical, or other vapors. Do not neglect
occasional conditions in which individuals may be placed.
18. Does the acclimatization of strangers in relation to the soroche
take place more or less quickly, and what are the conditions which
favor or delay it? Does this acclimatization have a lasting or merely
temporary effect? Do the negroes have more difficulty in becoming
acclimatized than the whites? And if the opportunity offers, it would
be interesting to make a series of experiments to ascertain the normal
pulse rate of the inhabitants of the plateaux, Indians, negroes, and
whites; taking care to repeat them on a great number of healthy per-
sons of both sexes, adults of verified age, and to make these experi-
ments at rest, standing and lying down, at a certain distance from
mealtime, and to note the outer temperature of the season, hot or cold.
19. If the symptoms of the soroche appear in animals, what are
their characteristics in the different animals and what are the condi-
Theories and Experiments 305
tions which give rise to them? Especially what are the causes which
give rise to the disease of mules known by the name of trembladera?
Are the domestic llamas and those used as beasts of burden equally
subject to this disease?
20. Is the mortality of certain animals (cats, for example), caused
by their sojourn in very lofty places, an established fact or not? And
if the fact is established, what are the symptoms which precede death,
and what are the probable causes of this mortaltiy?
21. Are there means of awarding off the soroche, and if there are,
what are they? Has anyone tried, for example, in Peru, as in Styria
and the Tyrol, the ingestion of small doses of arsenic to prevent the
fatigue of the ascent of mountains? Study particularly in this connec-
tion the effects of the plant known as cuca or coca, either chewed or
taken in an infusion, which they say has a remarkable prophylactic
power.
22. What are the means employed with the greatest success in
checking or lessening the symptoms produced by the soroche, either in
man or in the animals? (P. 113-117.)
As I said at the beginning of this first part of my work, I
shall not discuss in this historical section any researches which
rely upon the results of my own investigations or which oppose my
conclusions. My discussion of them will naturally take place in
the third part.
And for this reason I shall say nothing of the book recently
published by M. Jourdanet,140 in which he repeats, develops, and
supports by new proofs taken from the study of altitudes over the
whole earth the opinions suggested to him by observation of the
diseases of Upper Mexico. I shall borrow from this immense work
only the account of an important experiment in which appears
the first attempt made to study chemically the degree of the
anoxemia:
I decided to devote myself to this work of analysis about the end
of 1864. I found assistance— very worthy of special mention in this
book — in the laboratory and the cooperation of M. Romuald Zamora,
a Spanish gentleman, who studied the sciences in his hours of leisure.
I analyzed the blood of three rabbits by means of carbonic oxide, fol-
lowing the specifications given by M. Claude Bernard. I found an
average of oxygen which was very low, but not enough to justify one
in feeling authorized to make really legitimate general conclusions. I
also felt hesitant because of a consideration which I thought exceed-
ingly important; namely, that one could always ask himself whether
these same animals would not have given this same quantity of oxygen
at lower levels. In fact, differences in amount found in my previous
analyses of blood prove that the proportion of this gas is an individual
peculiarity, at least within certain limits. It seemed to me after that,
that this interesting point cannot be indisputably decided without a
double analysis of the blood of the same animal, drawn first at normal
306 Historical
pressure, and second, at a more or less pronounced decompression.
Therefore I again put off till a better time the realization of my wishes.
(Vol. I, p. 181.)
These wishes I had the good fortune to realize, thanks to the
generous assistance of my learned colleague. And we shall see
that I succeeded in proving how closely his anticipations agreed
with the truth. But for this demonstration, I refer the reader to
the second part of my book.
In the third part he will find the detailed history of the latest
aeronautic ascensions to great heights, and particularly of the one
which had so fatal an end. We shall then specify definitely the
causes of this disaster and draw from it the lessons it contains.
Limiting ourselves to the subject of the present chapter, we shall
say that the interpretations, given by the different scientific jour-
nals and others, of the causes of the death of Sivel and Croce-
Spinelli are merely those whose discussion fills the preceding
pages. There is nothing new in them which deserves to be noted
here, and all these ideas had already been given by authorities of
greater weight.
We shall except only the short discussion which arose on this
subject within the Academy of Medicine. We see that, in the
opinion of MM. Woillez, Mialhe, and Colin, the diminution of the
weight sustained by the body again plays the principal part; in
spite of the elementary principles of physics of which M. Giraud-
Teulon, M. Gavarret and many others have already reminded
them, they still harp on the theory of the Universal cupping-glass.
But M. Colin adds to that a hypothesis which alone would deserve
the honor of repetition, for it had been only very briefly suggested
by a few former authors, and M. Maissiat did not go so far as to
give it such importance. In his opinion, the escape of gases into
the intestine and the expansion of these gases by the decrease in
pressure played the chief part in the fatal ending. Here is the
passage in full:
M. Larrey: The ingenious experiments of M. Woillez and the new
researches he has made on the spiroscope would no doubt lead him
to the physiological study of respiratory phenomena at different alti-
tudes, and then to the hygienic prophylaxis of the violent disturbances
of this important function, under other influences. We should also
decide upon therapeutic measures, when asphyxia, for example, is
imminent and causes complex symptoms which rapidly become fatal,
through sudden rarefaction of the air or through the progressive
diminution of the air pressure. Finally, it would be desirable to
determine and check the measures by which artificial respiration could
Theories and Experiments 307
be established, for instance in the diving bell, comparable, in this
respect, to the basket of the aerostat.
The fatal disaster which has just startled the world of science and
the two victims of which were buried this very day urges me to make
this suggestion to the Academy, even if it is only a digression useful,
perhaps, to the interesting communication of M. Woillez.
M. Woillez: I cannot give an opinion here on so important a mat-
ter; but it seems to me that it is not only a question of respiration;
we must particularly take into consideration the decrease in the atmos-
pheric pressure for which the oxygen they had taken along could give
no help.
M. Colin: Since the question of the balloon has been brought up,
I should like to give my opinion of the causes of the death of the
aeronauts. Certainly these causes are multiple, especially those con-
nected with the decrease of pressure; some are already indicated by
the conditions in which the aeronauts were.
Two had lunched and they are dead; the other was fasting and he
survived. The escape of gases into the digestive tract of the first two
might have played a great part in the progress of asphyxia. We know
that this escape is very great in ruminants following the eating of
green fodder, and that it may, at ordinary pressure, produce sudden
death by asphyxia by immobilizing the diaphragm. No doubt this
escape is more limited in man: but it increases as a result of illness
and indigestion, and then, since the expansion of the gases increases
as the pressure decreases, the diaphragm is soon vigorously crowded
upward; its movements become very limited and finally become impos-
sible. We know that at a certain moment, when the traveller is climb-
ing high mountains, he is seized by lassitude, his arms and legs are
worn out; the muscles, irrigated by a blood which is imperfectly
oxygenated, lose their energy. The diaphragm shares in this fatigue,
and finally becomes inert, especially if it is crowded back by the
expansion of the gases of the stomach.
I know very well that aeronauts need to fortify themselves against
becoming chilled, and that fasting does not warm them, but they can
arrange their meals in such a way as to complete digestion before
starting, and replace fermentable food by respiratory food, by liquids
which stimulate and develop heat.
Observations made on the victims and the survivor show clearly
the chief cause of the symptoms. This cause is not, whatever M. Bert
may say, the lack of oxygen, for in the experiments the animals do
not die with the proportion of this gas which may be in the air at
7000 or 8000 meters. It is the decrease of pressure, as M. Woillez has
just said, which produces the serious symptoms, the hemorrhages in
the respiratory passages, the circulatory disturbances, etc.
M. Blot: M. Colin's last words seem to me to contradict what he
said at the beginning. So he explains death first by the compression
of the diaphragm and the lungs under the influence of the expansion
of the intestinal gases, and finally attributes it to the decrease in
pressure.
As to the comparison between the herbivores and man, it seems to
me very debatable.
308 Historical
M. Colin: I am surprised that M. Blot sees the slightest contra-
diction in my words. I said that the symptoms and death in ascen-
sions are due to several causes, among others the compression of the
diaphragm by the gases of the digestive tract and the decrease of
pressure on the tissues and the vessels resulting in pulmonary, nasal,
and other hemorrhages. Each of these causes has a part in the effect;
far from excluding each other, they are linked together.
M. Mialhe: I agree with M. Woillez that the decrease of the
atmospheric pressure was the principal cause of death, but I cannot
accept the idea of M. Colin that one should not eat before making
a balloon ascension. Man is not a ruminant, and things do not go on
within him just as they do in the herbivores.
M. Colin: What! Does man then have privileges in regard to diges-
tion? Does the stomach function otherwise in the abdomen of man
than in the abdomen of an animal? The dog which has eaten meat
and bread has in his stomach much gas which one can measure by
ligating the aesophagus and the pylorus. Why would not these same
foods also produce gases in the stomach of man? Have not the diges-
tive process and the fermentations uniform characteristics in species so
closely related?
I shall express myself later upon this question of the intestinal
gases; but now, seeing" the importance which M. Colin seems to
attribute to it, I cannot refrain from one remark: the desire of
contradicting must be a very strong passion in some persons, since
it has led a physiologist of this rank to say such strange things.
The last document which I shall submit to my readers is
perhaps still stranger. If there are some among them, as I fear,
who think that, in giving the history of mountain sickness, I have
displayed an excessive wealth of quotations and descriptions, they
will, no doubt, pardon me for this imposition when they consider
that in 1875, before the Geographical Society, before the Academy
of Sciences itself, the very existence of mountain sickness was
denied, a denial which depends upon the strangest of methods, or
rather which is the very absence of scientific method, because it
takes into account only the circumstances in which the travellers
felt no symptoms during their ascents.
The first communication from M. Virlet d'Aoust on this subject
is dated May 19, 1875. The official Proceedings 148 of the Geograph-
ical Society narrates it in the following words:
M. Virlet d'Aoust, on the occasion of the recent disaster of the
Zenith, made a communication about the effects of the rarefaction of
the air in the region of lofty mountains. In an ascent of Popocatepetl,
at an altitude of 4500 meters, he felt no other discomfort than a fatigue
more pronounced than on the plains. There are numerous examples
in the Andes of inhabited places at an altitude of 2000 and 3000 meters.
Mexico City is at an elevation of 2300 meters.
Theories and Experiments 309
A discussion took place in regard to the influence of atmospheric
pressure on human life.
MM. Antoine d'Abbadie, Maunoir, de Charencey, and de Puydt took
part in it. The last mentioned for two years travelled through the
valleys of the Andes, in Ecuador and Bolivia, living at altitudes of
4800 meters, always keeping his health and vigor. M. l'abbe Durand
confirmed this statement, according to M. Stuebel, who made an ascent
of Chimborazo two years ago. (P. 552.)
We can see by the account of Stuebel's ascent which we have
given into what an exaggeration M. l'abbe Durand has fallen. But
without discussing this for the moment, it is interesting to repro-
duce at greater length the arguments presented by M. Virlet
d'Aoust and his learned colleagues, according to an authorized
journal, the Explorateur:149
M. Virlet d'Aoust, on the occasion of the lamentable disaster to
the Zenith, which cost the lives of two young scientists, MM. Croce-
Spinelli and Sivel, recalled the circumstances of his ascent of Popoca-
tepetl, in April 1853, with the purpose of emphasizing the considerable
differences which exist between ascents of mountains and vertical bal-
loon ascensions in the atmosphere.
When one rises in the air by means of a balloon, says M. Virlet
d'Aoust, he finds himself successively plunged in layers of air, if not
of different compositions, at least of different densities, in which, how-
ever, the carbonic acid must diminish in proportion because of its
greater specific weight. This kind of ascension, moreover, is made too
rapidly for the organs of human life to have time to undergo sufficient
changes to make the successive differences in atmospheric pressure
endurable.
When one scales a mountain on foot, the layers of air have exactly
the same composition as on the plain, for these layers, though becom-
ing thinner, rise in currents from below up to the highest summits.
The result is that any experiment which has for its sole purpose the
determination of differences in the composition of the air at different
heights should be carried out vertically in a balloon and not in a
mountain ascent.
The ascent of Popocatepetl (the smoking mountain) by M. Virlet
d'Aoust involved numerous companions, and was, so to speak, an
international expedition. The United States, England, Mexico, Ger-
many, Belgium, Switzerland, Italy, and France were represented.
Although the plain and the city of Mexico have an elevation of
about 2300 meters above sea level, life there is very comfortable; public
health is perfect and free from any endemic disease. The travellers
halted at the foot of the cone at an elevation of more than 4000
meters; they had reached this spot on horseback without the least
inconvenience and without feeling the slightest effect of the rarefac-
tion of the air. The difficult part was the ascent of the cone, a regular
sugar loaf, which had to be climbed on foot. That requires four hours
of very difficult walking, although the descent is made in less than a
half-hour. Neither M. Virlet dAoust nor his companions experienced
310 Historical
any discomfort except that resulting from a somewhat accelerated
respiration, and a little more heaviness in the limbs ....
From these experiments M. Virlet d'Aoust has drawn the conclu-
sion that the so-called mountain sickness is merely great fatigue re-
sulting principally from heaviness due to the decrease of the layer of
air which surrounds the traveller and which supports him in the lower
regions ....
M. d'Abbadie asked the author whether a distress manifested by
dizziness and vomiting did not appear on lofty peaks. M. Virlet d'Aoust
stated that he felt nothing of the sort nor did his travelling com-
panions. M. de Puydt said that he had crossed the highest peaks of
the Andes, from the equator to the sixth degree, north latitude; that
he had reached altitudes of 4800 meters and that he had never felt
any of these fatigues; and yet he had travelled more than 450 leagues
in the Andes. M. l'abbe Durand supported this opinion, recalling the
official ascent of the great volcanoes ordered by the government of
Ecuador. Finally, M. Maunoir said that the effect of ascents, even in
the mountains, must vary with the health conditions and the constitu-
tion of the traveller. (P. 401.)
M. Virlet d'Aoust130 returned to this subject in the session of
July 7; he still followed the same strange method:
M. Virlet dAoust, resuming the subject studied in a former
session, that is, the effect of the rarefaction of the air in the higher
regions of the atmosphere, reported an ascent of the volcano of
Arequipa or Misti, the altitude of which is 5650 meters, during which
the travellers were not at all inconvenienced (Reference to the Bulle-
tin). (P. 107.)
The Explorateur of July 15, 1875, is much more explicit:1,1
Mountain sickness. In support of what he had previously said, on
the occasion of his ascents of Popocatepetl and Ixtaccihuatl, in refer-
ence to the so-called mountain sickness, M. Virlet d'Aoust reported
another ascent, that of the volcano Misti, more often designated by
the name of the volcano of Arequipa, in Peru, which led to the same
conclusions. Dr. J. T. Coates, of the United States, who made the
ascent, left Arequipa September 22, and camped for the night at the
foot of the mountain, situated 30 miles northeast of this city. The
next day very early, accompanied by three guides and furnished with
two aneroid barometers, he undertook the ascent. The little caravan
could travel on horseback at first; but after an hour, since the grade
became too steep and the difficulties kept increasing as they advanced,
they had to continue on foot.
After ten hours of difficult walking, at half-past six in the even-
ing,, they finally reached the summit of the volcano, without having
experienced hemorrhages, or difficulties in breathing, or nausea, or
headaches, or any other of those painful sensations which, it is
claimed, should be felt by persons who venture in the mountains to
altitudes of more than 3000 meters ....
Finally, M. Virlet d'Aoust thought he should mention another still
Theories and Experiments 311
higher ascent which might have taken place in New Guinea. Several
journals announced recently that the Englishman, Captain Lawson,
had discovered in this huge isle of the ocean a mountain called Mount
Hercules, which has an altitude of 10,929 meters above sea level, that
is, 1262 meters more than Mount Everest, in the Himalayan chain,
hitherto considered the highest point of the whole world. The
Explorateur has suggested that the welcome to this alleged discovery
should be given with certain reservations. At any rate, according to
his story, when Captain Lawson attempted the ascent of Mount
Hercules, he could ascend only to the height of 8435 meters, that is,
an altitude almost equal to that reached by the balloon Zenith in its
last and fatal ascension; but at this height, blood issued from his eyes
and ears, and he nearly died as a result of the rarefaction of the air.
This statement, like the discovery of a mountain claimed to be the
highest in the world and yet so late in recognition, requires confirm-
ation. (P. 65.)
Nothing has confirmed this last account, which no one, unless
he is exceedingly credulous, could believe. But I will not continue;
the following chapter will contain the critical discussions.
I Loc. cit., Chap IX— Sevilla, 1590.
'Novum organum, Book II, 11. Translation by Lorquet, p. 85.
3 Relation de divers phenomencs arrives dans le vuide, a dcs animaux qu on y avoit
cnferm.es. — Collect, acad., foreign part, vol. I, p. 46-61>.
4 I do not know their exact date. Musschenbroeck lived from 1692 to 1761; the volume
of the Collection academiquc in which they are included appeared in 1755.
5 Experience du Vuide— Histoire de I'Acad. dcs sciences de Paris, K6S; vol. I, p. 45.—
Collect, acad., French part, vol. I, p. '23. .„..,«. i -ir
8 Boyle, R., Neiv Pncumatical experiments about Respiration. Plulos. Transact., vol. V,
p 2011-2058, 1670.— Extracted and translated: Collect, acad., foreign part, Vol. VI, p. 23-59; 1761.
7 A new Experiment concerning an Effect of the varying Weight of the Atmosphere upon
some Bodies in the Water.— Philosoph. Transact., VII, 1672; p. 5156.
8 Huyghens and Papin, Some Experiments touching Animals, made in the Air-pump.—
Philosoph. Transact., X, p. 542-543.— Extracted and translated, Collect, acad., foreign part, vol.
9 To try the Effects of the Pncumatick Engine exhausted in Plants, Seeds, Eggs of Silk-
worms. Philosoph. Transact., vol. II, p. 424-425; 1667. .
in Sur la rarefaction et la condensation de Fair.— Hist, de I'Acad. des sc. de Paris, year
1705, p. 15; and Collect, acad., French part, vol. II, p. 181.
II Sur la mort des animaux dans le vuide, Acad, des sc. de Bologne.—Coll. acad., foreign
part, vol. X. p. 53; 1773. . .
12.S'»r la mort de quclques especes d'oiseaux et dc grenouilles dans un air, renferme.
Acad, des sc. de. Bologne.— Collect. ' acad., foreign part, vol. X, p. 313-321.
13 Sur la cause de V extinction c la flamme et de la mort des animaux dans un air ferme.
Soc. roy. des sc. de Turin, vol. II, years 1760-1761; p. 168.— Collect, acad., foreign part, vol. XIII.
14 Darwin. Experiments on Animal Fluids in the exhausted Receiver. — Philos. Trans., vol.
LXIV, p. 344-349, 1774.
15 De Motu Animalium, Pars altera.— Rome. 1681.
16 I could not procure this book. But probably this solution is the one which Veratti
quoted and which we have just mentioned.
17 hoc. cit.: Relation abregee, etc.. 1744.
^ Loc. cit.: Memoires philosophiques, 1787.
19 Elementa Physiologiae corporis hutnani. Lausonne, 1761.
20 De mcteoris aqueis, p. 40. I could not procure this work.
21 Rechcrchcs sur les Modifications dc V atmosphere, vol. II — Geneva, 1772.
23 Loc. cit. : Nouvelle description, etc., 1785
23 Discours en forme de dissertation sur I'etat actuel des montagnes des Pyrenees.—
Paris, 1776.
** Voyage dons les Alpes— Geneva, 4 vol. in 4°; 1786 to 1796.
25 Essai de Physiologic positive appliquee specialcmcnt a la medicine pratique, vol. I,—
Avignon, 1806.
28 Art. Air, Diet, des Sc. medi., vol. I, p. 24S; Paris, 1812.
27 Des effets de la pesanteur de Fair sur 1'homme considere dans I'etat de sante. — Theses dc
Paris: 1813. .
28 Deuxicmc Memoir e sur la chaleur animal e ; 1813. Oeuvres de Legallois, avec dcs notes
de M. Pariset, vol. II— Paris. 1830.
29 Description des Pyrenees, 2 vol.---Paris, 1813.
30 Memoirc concernant les effets de la pression atmospherique sur le corps humam, et
['application de la ventouse dans differents ordres de maladie— Paris, 1819.
312 Historical
3\Loc. cit.: Journal of a Tour, etc.; 1820.
32 Additional Observations on the Natural History and Physical Geography of the Hima-
layah .Mountains, between the River-Beds of the Jumna and the Suite]. — The Edinburgh Journal
of Science, conducted by D. Brewster, vol. II, p. 277-287, 1825. Read before the Royal Society
of Edinburgh, December 10, 1824.
33Loc. cit.: The Ediub. Journal of Science, vol. I; 1824.
34 Loc. cit.: Account of Koonawur, etc. — London, 1841.
35 Loc. cit.: Narrative of a journey, etc.; vol. I. — London, 1840.
30 Loc. cit.: Asiatic Research, vol. XIV; 1822.
31 Loc. cit.: Nouveau Journal de mede.ine, vol. VII; 1.-20.
. cit.: Bibl. univ., vol. XIV; 1820.
30 Loc. cit.: Bibl. univ., vol. XXIII; 1S23.
40 Observations sur la vitesse du pouls a differents degris de pression atmosph. — Journ. de
Physiol, de Magendie, vol VI, p. 1-13; 1826.
41 On the Effects of removing Atmospheric Pressure from the fluids and solids of the
human Body. Transactions of the Medico-Cliirurgical Society of Edinburgh, vol. Ill, p. 448-458;
1829.
42 Dictionnaire de Medecine, article Atmosphere, vol. IV; 1833.
43 Effects of Mountain Elevation upon the human Body.— London, Med. Gaz., vol. XIV, p.
207, 520; 1834.
44 Trait e de Physiologic, Tourdan translation, vol. VI; 1837.
45 Loc. cit.: Reise in Chile, etc.; 1836. *
46 Loc. cit.: Ann. de Chimie, Second series, vol. LVIII, 1835.
47 Sur la composition de I'air qui se trouve dans les pores de la neige. Ann. de Chim. et
de Phys., Third series, vol. I, p. 351-360; 1841.
48 Loc. cit.: Lcttre a Delambre. Ann. du Museum; vol. II; 1805.
40 Loc. cit. : Ibid.
50 Loc. cit.: Ann. de Chimie, Second series; vol. LXIX; 1838.
51 The fact that atmospheric pressure is the real cause of the maintenance of articular
adherences was discovered by the French physiologist Berard, something not generally known.
Guerard, who bore witness to it, expressed himself as follows:
"Long before the work of these physiologists was known in France, M. Berard, in a
competition for the_ Central Board (about 1828 or 1S29), had had printed, according to the practice
at that time, a series of propositions upon which the argument was based. One of these propo-
sition was worded as follows: Atmospheric pressure can aid or hamper disjointing, according
to circumstances. M. Berard quoted an experiment which he had devised, and which consisted
of removing all the muscles which hold the thigh to the pelvis and of cutting the capsular liga-
ment. When the leg was pulled, the adherence of the head of the femur to the cotyloid cavity
under the effect of the weight was sufficient so that the body could be dragged on the ground
without the two parts of the articulation separating." {Ann. d'hvg. publiquc ct de med. leg.
Second series, vol. I, 1854, p. 304.) *
What we really owe to the German physiologists is the mistaken application they have
made of this truth to the theory of walking.
52 Rechcrches sur les effets physiologiqucs et therapeutiques de la compression ct de la
rarefaction de I'air, taut sur le corps que sur les membrcs isoles. Ann. gen. de Med., Second
series, vol. IX, p. 157-172: 1835.
53 De I Hemospasic.—Rccucil de Memoires sur les effets therapeutiques de cette mcthodc
de traitemcnt. — Paris, 1850. *
54 Rapport sur un Memoire ayant pour litre: De la Condensation et de la Rarefaction de
I' Air, apSries sur toutc I'habitude du corps on sur les membrcs seiilcmcut, consid recs sous
leurs rapports therapeutiques. par M. Th. Junod, M. D.—Cpt. R. Acad, des Sc, vol. I, p 60-
65; 1835.
50 In fact, that is what Clanny himself says: "It is interesting to note that at the same
time Sir James Murray of Dublin, Th. Junod of Strassburg, and I invented a similar apparatus,
for the purpose of lessening the pressure of the atmosphere on the surface of the body, with-
out anything having been published previously in any journal." {Researches of M. Junod into
the physiological and therap. effects of compression and rarefaction. The Lancet, 1835-36; vol.
II, p. 359.) •
Clanny and Murray had invented only the great cupping-glass. — Apparatus for re-
moving the Pressure of the Atmosphere from the Body or Limbs. The Lancet, 1831-36; vol. I.
p. 804-805.
66 Junod, _ Traite theorique et pratique de I'hemospasie.— Paris, 1875.
57 Considerations sur les effets therapeutiques de I'hemospasie, d'aprcs les observations re-
cueillics en Alqerie par T. Junod.— Paris, 1858.
68 Bibl. univ. de Geneve, Second series, vol. V, p. 151; 1836.
59 Ascension au Faulhorn. Revue medicate, 1841, vol. IV.
60 Loc. cit.: Influence, etc.— Revue medicale, 1842, vol. IV.
61 Loc. cit.: Peru, Reiscskizsen, etc.; 1S46.
62 Loc. cit.: Practical observations, etc.; vol. LVII, 1812.
63 Voyages au Perou et a Mexico, vol. I, I am borrowing this quotation from Flemeing,
Ringuet translation; loc. cit., De V influence, etc.— Perigueux, 1869.
rA Etudes ilc Physique animale.— Paris, 1843.
05 Betrachtung der Gcbirgsluft und der Lebenszueise dcr Gebirgsbewohner in Besua ihres
F.iuflusses auf Bltttbereitung unii auf das Vorkommen gdvisser Kranhhcitsformen. Oesterr,
Med. Jahrb., vol. XXIIL— Analyse in Schmidt's Jahrb.. vol. XXXIII, p. 298, 1842.
015 Notes sur les Causes de la lassitude et de lanhelation dans les ascensions sur les men-
tagnes les plus elevecs.—Rev. Med., 1844, vol. Ill, p. 356-368.
67 Sur la Cause des plienomenes physiologiques que Von trouve quand on s'elifve d une
certaine hauteur dans les montagnes.—Cpt. R. Ac. des Sc, vol. XX, p. 1501; 1845.
68 Physiologic des Atmens — Karlsruhe, 1645, p. 84-89.
™ Loc. cit., Mem. sur les phen. physio!.; 1845.
70 Allegemeine Zeitung Misccllcn: Erstcigung des ll'etterhorns, reproduit in extenso dans
Dolfus-Ausset, loc. cit.. Materiaux, etc., vol. IV, p. 417-429.
71 Loc. cit.: Souvenirs, etc., vol. II, 1S50.
Theories and Experiments 313
72 Esplorazioni Ji N.-M. Przevalski tiella Mongolia orientate e sulle falde N.-E del Tibet
(187M873). Cosmos di Guido Cora, vol. II, p. 14-19, 164-175 and 261-277.— Turin, 1874.
73 Essai sur t'Emploi de lair comprime. — Paris-Lyons, 1850.
74 Observations tcndant a demontrer que, dans les ascensions sur les hautes montagnes, la
lassitude et t'anhelation eprouv es par la plupart des exvloratcurs n'ont pas pour cause une
insuffisance d'oxygene dans I' air respire. Cpt. R. Acad, des Sc.„ vol. XXXIII, p. 198; 1851.
75 Note sur les Effets de la diminution de la pression 'atmospherique sur les animaux.
Cpt. R. Acad, des Sc, vol. XXXVII, p. 863; 1S53
76 On the Nature and Causes of the physiological phenomena comprised in the term
"Mountain Sickness" more especially as experienced among the Higher Alps. — Assoc. Med.
Journ., 1S53, p. 49 and 80.
77 Die Bergkrankheit, oder der Emfluss des Ersteigens grosser Hohen auf den thxenscheyi
Organismus. — Leipzig, 1854; in octavo, 140 p.
78 Des Climats de montagne consideres an point de vue medical.— Arch des Sc. phys. et not.
de Geneve, vol. XXXII, p. 265-306; 1856.
79 Lehrbuch der Physiologie des Menschen. Braunschweig, 1844.
80 Recherches de Pathologic comparce. Cass el. l€53.
81 Memoir e sur la pression atmospherique dans ses rapports avee I'organisme vivant.
Cpt. R. Acad, des Sc, vol. XLIV, p. 233; 1857.
^Ueber den Einfluss, welchen der Wechsel des Luftdruckes auf das Blut ausubt. Mul-
ler's Archiv.; 1857, p. 63-73. _ *
83 Du role des principaux elements du sang dans t'absorption on le degagement des gas de
la respiration. Ann. des Sc. Natur. Fourth series; Zoo!., vol. VIII, p. 125; Kv~>7.
84 Ueber die im Blute entlialtenen Gaze : Sauerstiff, Stickstoff und Kohleusaiire. Poggen-
do-rff's Annalen, 1S37; translated in Ann. des Sc. nal., Zool. Seco nd series, vol. VIII, p. 79;
1837.
85 For the development of this view see: Vierordt. Physiologie des Athmens — Karlsruhe.
1845.
iG Traite de Physiologic.— Paris, First edition, vol. I, 1857; Third edition, vol. I, 1868.
87 De la chaleur produite par les Stres viyants, Paris, 1855.
83 Climats de montagne, etc., Second edition, 1858.
89 Bibl. univ. de Geneve, Fifth series, vol. II, p. 647, 1S5S.
90 Du froid thcrmometrique et de ses relations avec le froid physiologique dans les plaines
et sur les montagnes.— Mem. de I Acad, des Se. de Montpellier, vol. IV, L859.
01 hoc. cit. De la phthisis, etc., 1862.
92 Les Altitudes de I'Amerique tropicale eomparccs an niveau des mers, au point de vue
de la constitution medicate. — Paris, 1861.
93 De V Anemic des Altitudes et de I'Anemie en general, dans ses rapports apec hi pression
de V atmosphere.— Paris, 1863. *
94 Le Mexique et I'Amerique tropicale: climat, hygiene et maladies.— Paris, 1S64.
05 Gazette hebd. de med et de chir., 1863, p. 777
rjaGaz. hebd. de med. et de chir., 1863. p. 778-781.
97 Gaz. hebd., 1863, S17-S21 .
aiGaz. hebd., 1864, p. 33-37.
"The average of the intra-pulmonarv air circulation tor Vierordt was exactly 6 liters, that
is, equal to that observed by Coindet.
100 Gaz. hebd., 1864, p. 234, 265, 371. 450, 545, 579, 674.
101 Gaz. hebd., 1805, p. 145-151.
102 Traite elementaire de Physiologic, chap. IV, Section 138.
103 Gaz. hebd., 1865, p. 467-470.
104 This figure is relative to experiments made on Indians. (Gaz. hebd., 1864, p. 36.)
105 Recherches sur la quant d'ac carb. exhale par le poumon dans I'espdee humaine. Cpt.
R. Acad. des. Sc. vol. XVI, p. 113, 1843.
106 Gazette hebdomadaire, 1865, p. 468.
107 De la Respiration sur les hauls plateaux de I'Anahuac.—Rec. de Mem. de med. milit,.
Third series, vol. XIV, p. 512-516, isr.;.
103 Article Air from the Diction de Med. et de Chir. pratiques— Paris, 1864.
109 Die Travail dans I'air comprime. — Paris. 1863.
110 Considerations odncrales sur les maladies principals qui ont regne sur les chevaux et
mulcts du corps expeditionuaire due Mexique pendant la periode de 1862 a 1863. — Journal de
medecine veterinaire militairc, vol. Ill, March, April, May, 1865; vol. IV, June, July, August,
1865.
111 Article Altitudes from the Dictionnaire encyclopedique des Sciences medicales.—Faris,
1866.
112 Etude de quelques-unes des variations que {'altitude fait sentir a 1'air ambiant ct de
rinftuence de ces variations sur I'homme. These de Paris 1866.
113 Influence de I'altitude des Heux sur les f auctions physiologiques — Paris, 1867.
U4Kaufmann. Cpt. R. de VAcad. des Sciences, vol. LXV, p. 317, 1867.
115 Le Mexique considere au point de vue medico-chirurgical.—'Paris, vol. I, 1S67; vol. 11.
1868.
110 Article Atmosphere. Dictionn. encyclopedique des Sciences medicates.— Paris, 1867; p.
111-164.
117 De I Influence de la compression et de la rarefaction de 1'air sur les actcs mecamques
de la respiration. Thierry-Mieg translation— Gaz. med. de Paris, 1868.
118 De ("Influence de In pression atmosph. ct de I'altitude sur la sante et les maladies de
I'homme et des animaux. Ringuet translation.— Perigueux, 1S69.
119 Theses du Concours d' agre nation. — Paris, 1869. - .
120 Traite elementaire de physiologic, Book II. Chap. I, Section 244, Sixth edition; Paris,
1870.
121 Une Ascension au mont Blanc. Bibl. univ., Fourth series, vol. XXXI, p. 79-95, 1856.
uzLoc. cit.: Bibl. univ.; 1865.
123 Loc. cit.: Deux ascensions, etc.; 1869.
314 Historical
ni Observations sur la temperature du corps humain a differentes altitudes a I'etat du
repos et pendant I'acte de i'ascension. Bibl. univ. de Geneve, Arch, des Sc. pliys. et nat.; Fifth
series, vol. XXXVI, p. 247-289, 1S69.
^Experiences sur la temperature du corps humain dans I'acte de I ascension des mon-
tagnes — Extract from Bulletin de la Societe medicate de la Suisse Romande, First series, Geneva
and Bale, 1871; Second and Third series, 1874.
120 In his ascents M. Forel had not yet gone beyond la Cima di Jazzi (3818 meters).
127 The effect of exercise on the bodily temperature.— Journal of Anat. and Physiol., Second
series, vol. VII, p. 160-119, November, 1872.
12S Observations on the Effects of Exercise on the Temperature and Circulation. Proceed,
of the Roy. Soc, XXI, p. 374, 1872-73.
129 Sur le Mai des Montagues. — Bullet, de la Soc. med. de la Suisse Romande, 1874, p.
72-79.
130 Sur le Mai des montagnes. — Bull, de la Soc. med. ae la Suisse Romande. 1874, p. 136-
140.
lj" Tvndall, Hours of Exercise in the Alps, Second edition.— London, 1871.
"-Histoire du mont Blanc— Paris, 1873.
133 Loc. cit.: On mountains, etc., 1872.
134 Loc. cit. : The adventures, etc., 1853.
135 Loc. cit.: Lahore to Yarkand, etc., 1873.
lmLoc. cit. The Jiiinnoo, etc., 1875.
137 Abeokuta — London; 2 vol., 1863.
13S La Station medicale de Saint-Moritz (Engadine). — Paris, 1S73.
139 Effets physiologiques du climat et des eaux de Bareges. — Mem. de VAcad. des. Sc.
Inscr. et Belles Lettres de Toulouse, Seventh series, vol. IV, p. 214-231, 1S73.
140 L'hommc americain, 2 vol. — Paris, 1839.
^Instruction pour le Pcrou. Bull, de la Soc. d'Anthrop. de Pans, vol. II, p. 85-137.—
Paris, 1861.
ie Les altitudes de I'Am. trop.; Paris, 1861.
143 Gas. hebd.; 1.863, p. 779.
144 Descendance de I'homme, vol. I, p. 330.
145 Influence de la pression de I'air; Paris, 1875.
146 Influence de la pression de I'air sur la vie de I'homme, 2 vol. — Paris, 1875.
147 Bulletin de I'Academie de medecine. Seance du 20 avril 1875, Second series, vol. IV, p.
409-471.
148 Bull, de la Soc. de Geogr. Sixth series, Vol. IX, 1875.
149 First year, first volume. — Paris, 187a.
130 Bull, de la Soc. de Geog., Sixth series, vol. X.
151 First year, second volume.— Paris, 1875.
Chapter IV
SUMMARY AND CRITICISMS
The time has come to summarize the long series of observa-
tions, experiments, and theories, the details of which we have
just related. After placing before the eyes of the reader nearly
all that has been written about the effect of decreased atmospheric
pressure, by the laborious but certain method of word for word
quotations, we should now simplify his task by condensing all
these varied assertions, often redundant and sometimes contradic-
tory.
We must, moreover, subject to careful examination the expla-
nations suggested, opposed, or eclectically collected by travellers,
physicians, physiologists, and physicists, who have considered in
its various aspects this question, which is apparently so complex,
but really so simple, as we shall show. In this part of my task I
shall, of course, set aside the arguments drawn from my own
experiments. It is by ideas previously known that I hope to prove
that at the time when I began my researches, there existed in
science no theory — I do not say demonstrated, for that is evident —
which could sustain thorough criticism. Even the truth, when it
was found, was mingled with so many errors or was so unfurn-
ished with proofs that it could not force its clear evidence upon
rebellious minds. Now anyone is right only when he can prove
to everyone that he is right: "To keep on answering," Voltaire
said, "is to prove that no answer has been given."
The present chapter is naturally divided into three parts: the
conditions under which mountain sickness appears, the summary
of the symptoms which constitute it, the careful examination of
the theories suggested to explain it.
1. Conditions Under Which Mountain Sickness Appears.
The most general fact emerging from our study is that when
315
316 Historical
men and animals ascend to great heights above sea level, they
always finally experience a series of more or less serious symp-
toms, the combination of which constitutes mountain sickness.
The very existence of these symptoms, however, has been
denied, as we have seen; but these denials, which are rash and
unscientific generalizations upon a few isolated cases, do not merit
our attention here.
The first striking fact, when we examine the series of data
which we have collected, is the difference in altitude at which the
dangerous symptoms appear, depending upon whether we are
dealing with mountain journeys or balloon ascensions. Whereas
in the first case travellers often become ill at about 3000 meters,
and almost never mount above a height of 5000 meters without
serious suffering, Gay-Lussac, Barral and Bixio, and M. Glaisher
felt only a few slight disturbances at 7000 meters. In a moment,
we shall easily find the reason for this enormous difference.
On earth as in the air, the severity of the symptoms keeps
increasing with the altitude; but in its ascending progress, it
follows a law of progression, not of proportion. Up to 3000 meters,
a traveller who set out from the level of the valley, 1000 meters
for example, will be warned of the decrease of pressure only by
a slight increase in pulse and respiratory rates; from 3000 meters
to 4000 meters, the symptoms increase considerably in intensity;
above that, each ascent of a few hundred meters is marked by a
progressively increasing aggravation of them, and a moment comes
when it is harder to climb 50 meters than it was to ascend 500
meters at the beginning of the journey. It is not surprising,
therefore, to see, as Captain Gerard reported, mountaineers of
Koonawur, accustomed to observing sensations of this sort, esti-
mate the altitude of the point which they have reached by the
difficulty in breathing experienced there.
The altitude at which the symptoms of mountain sickness
appear varies considerably in the different regions of the earth.
We have seen that in the Pyrenees serious symptoms appear only
near the highest summits, that is, above 3000 meters and then they
are very rare. At the same level in the Alps the accounts of trav-
ellers begin to indicate some disturbances; they are rather
customary between 3500 and 4000 meters; above that, their exis-
tence constitutes a rule from which far fewer persons escape than
the editors of the Alpine Clubs would have us believe. Etna, with
its 3313 meters, is in this respect, as we have said, a limited moun-
tain, as is the Peak of Teneriffe (3716 meters). In the Caucasus
and the mountains of Armenia the level at which almost everyone
Summary and Discussion 317
is severely attacked seems a little higher than in the Alps; on the
volcanoes of the Pacific, which exceed 4000 meters, the sickness is
hardly worse than on the Peak of Teneriffe; the same thing is true
of the Kamerun Mountains, and on Kilimandjaro, New reached
an altitude of about 5000 meters without serious distress; in North
America, Fremont and his companions were ill at about 3500
meters; but in Mexico one must mount above 4500 meters, to expe-
rience perceptible discomforts; they are not always very serious
even on the summit of Popocatepetl (5420 meters). The long
mountain chain of South America cannot be crossed at any point
from Chile to Colombia without inflicting the terrible puna upon
most of the travellers. But it seems that these sufferings do not
appear at a completely uniform height; whereas on the passes of
Santiago in Chile many are sick below 4000 meters, and almost
all foreigners are severely attacked at La Paz (3720 meters), and
even at Chuquisaca (2845 meters), and all at Cerro de Pasco
(4350 meters), the ascent of the mountains near Quito causes
almost no symptoms up to 5000 meters, and a thousand meters
more present no unsurmountable difficulties from the physiological
point of view.
The immense mountains of central Asia may be compared to
the Andes of Upper Peru from the standpoint of the line where
mountain sickness appears. Passes less than 4500 meters high are
crossed without serious sufferings; there are some more than 5500
meters high which are considerably frequented; several travellers
have reached,' 6000 meters, and the Schlagintweit brothers
ascended to the prodigious height of 6882 meters on the sides of
Ibi-Gamin.
These inequalities, from our standpoint, among the different
mountainous regions of the earth, stand out among the multitude
of facts which we have listed; but one can easily find numerous
exceptions to these general rules. Indeed, and this is not the least
interesting fact revealed to us by these multiple observations, we
see that in the same region of the earth, in the same mountain
chain, certain definite places are particularly feared by travellers
and natives; and these places are not always the highest, far from
it. This peculiarity is noted even in the ascent of a given moun-
tain; for instance, the Couloir of Mont Blanc, where symptoms
often appear which disappear on the summit. In a word, and these
facts have been noted particularly in the Andes and the Himalayas,
the intensity of the symptoms is not always in proportion to the
altitude reached. This was the origin of strange hypotheses imag-
ined by the natives, to which travellers too often gave credence;
318 Historical
and thence came also the belief in metallic emanations, mephitic
gases issuing from the ground, and fatal exhalations from different
plants.
But, barring these very interesting exceptions which we shall
try to explain in another part of this work, the differences in aver-
age height at which serious symptoms appear according to the
parts of the world in which they are observed are in a remarkable
agreement with differences in the altitude of the line of perpetual
snow, when we consider them as a whole. The summary which
we inserted earlier (see page 16) on this latter subject facilitates
this comparison for the reader. But we must not go so far as to
believe, as some travellers have done, that a direct relation,
almost of cause and effect, exists between these two distinct
orders of phenomena. Very evidently, no one has ever complained
of mountain sickness in the polar regions, where the lowest hills
are eternally covered with snow. But without having recourse to
this reductio ad absurdum, we see that in our Alps it is almost
always 500 meters at least above the line of melting where physi-
ological disturbances appear with sufficient intensity to attract
attention. The same thing is true upon the volcanoes of Ecuador
and Mexico, the Rocky Mountains, and many other points. On the
contrary, on the Bolivian Andes and still more on the Himalayas,
the narratives previously published show us that travellers may
be very sick when they are treading terra firma, and are still quite
far from the zone of perpetual snow. But it is no less true to say
that, in a general way, the higher the line of perpetual snow, the
later will travellers in their ascent be threatened with the symp-
toms which we have so often described.
Besides these irregularities due to exterior circumstances, there
are some which depend upon the idiosyncracies of the travellers
who are subjected to the effect of decompression.
Indeed, in the same region, on the same mountain, we see
travellers sometimes complaining of severe sufferings, sometimes
rejoicing or expressing surprise at having felt almost no distress.
On the pass of Cumbre of Uspallata, most of those who are crossing
the Andes are attacked by the puna; Samuel Haigh, Schmidtmeyer,
and many others have testified to it: but we have seen that Miers,
Brand, Strobel, etc. escaped it entirely. Whereas von Humboldt
and Bonpland were very sick in their ascents of Chimborazo, M.
Boussingault and Colonel Hall, who ascended higher than they,
experienced only slight symptoms, and M. Jules Remy, who says
that he reached the summit, states that he felt no symptom of ill-
ness, On Popocatepetl, Bacon Gros and his six companions, and
Summary and Discussion 319
later M. Laverriere, complained of real distress; MM. Turqui and
Craveri, M. Virlet d'Aoust declare that they were completely-
spared, while the Scientific Commission of Mexico was a little less
favored.
These differences are still more striking on less lofty moun-
tains. Riche and Blavier, when attacked by hemoptysis, gave up
climbing the summit of the Peak of Teneriffe, which von Hum-
boldt, Leopold de Buch, Elie de Beaumont,1 and so many others
reached without trouble. On Etna, Count de Forbin and A. de
Sayve suffered greatly, whereas Spallanzani was unaffected, and
Ferraro claimed to feel better than on the plain.
The same thing is true of the Alps. In the hundreds of ascents
of which its summit was the goal, Mont Blanc has given us the
most contradictory results. De Saussure, Beaufoy, Clark and
Sherwill, Hawes and Fellowes, Bravais, Martins and Lepileur,
attest to violent distress, which they conquered only by prodigies
of energy ;on the contrary, Clissold, Piachaud, and Albert Tissan-
dier were hardly ill at all. I have heard "Alpinists" of repute state
that they had experienced absolutely nothing unusual in this
ascent which was formerly so much dreaded. By a striking
contrast, Laborde, the brother of M. Lepileur, etc. were ill when
they ascended merely to the Grand Saint Bernard (2490 meters) ;
Spitaler and his companions relate the most painful details about
their ascent to Venediger (3675 meters), when Desor and Gottlieb
Studer affirm that they felt absolutely nothing when they ascended
the Jungfrau (4170 meters) . In Armenia, Radde lay down exhaus-
ted at 3700 meters, whereas daring travellers almost with impunity
trod the summits of neighboring mountains of far greater height,
Elbrouz (5620 meters), Kasbek (5030 meters), and Ararat (5155
meters). More than that, in 1868, Freshfield, Moore, and Tucker
made the ascent of Kasbek without any suffering; in 1874, moun-
taineers who were no less experienced, Gardiner, Grove, Walker,
and Knubel suffered considerably on the same ascent. I shall not
mention other examples. We need only refer to what we have said
in the preceding chapters to find, among so many observations,
examples of inequalities no less great noted in the Pyrenees, the
Himalayas, and other mountainous regions.
These differences are especially striking when they appear in
travellers who, in apparently similar conditions of health, hygiene,
and previous training, make the same ascent simultaneously. On
Pichincha, Ulloa fell fainting; La Condamine felt no difficulty in
breathing. While ascending Cotopaxi (5943 meters), one of
Steubel's muleteers was so sick that he could not go beyond 5600
320 Historical
meters; another felt absolutely nothing. On Mount Etna, de Gour-
billon felt nothing, whereas his companion Wilson suffered greatly.
In the ascent of the Finsteraarhorn (4275 meters), Hugi was in
very good condition, as were his companions, except one of the
sturdiest guides of the Oberland, who had vertigo and nausea. On
the glacier of the Maladetta, Neergaard stopped, unable to continue
an ascent which the celebrated geologist Cordier finished without
any trouble. MM. Lortet and Durier ascended Mont Blanc on the
same day; the accounts of their sensations are as dissimilar as
possible. At 5300 meters, Croce-Spinelli in his balloon was seized
with evident oppression; his travelling companions said that they
experienced nothing.
But that is not all; the same person, in conditions which seem
to him identical, making the same ascent on two different occa-
sions, does not always have the same sensations. On his first
ascent of Buet, Canon Bourrit fell unconscious; the next year, he
had no special experience. On the Breithorn (4100 meters), M.
Lepileur, in 1875, felt no discomfort, whereas the following year
he was seized there by an unconquerable drowsiness. There is a
similar lack of agreement in the three ascents of Mont Blanc by
M. Tyndall, and the two by M. Lortet. Observations made on the
guides are still more conclusive.
We must also note that while certain persons seem extremely
sensitive to the effects of ascents, others without any complaint
pass beyond the level where the great majority of travellers are
attacked by the usual symptoms. We saw that Dr. Martin de
Moussy had felt the puna at 1970 meters, whereas Jules Remy
could ascend almost with impunity to the summit of Chimborazo
(6420 meters). Victor Jacquemont seemed particularly immune
in this respect, as we can see from the excerpts from his letters.
Moreover, these facts are well known to all mountaineers; it is
known that certain guides are unable to follow "their gentlemen"
beyond a certain level, and travellers who were daring and tire-
less on mountains of the second rank have had to renounce
reaching the highest summits of the Alps.
The numerous ascents, the narratives of which we have given,
definitely differ then from one another in regard to mountain sick-
ness, first, for reasons which seem to depend upon the mountain
itself, and second, for reasons which depend upon the travellers;
the latter may be constant or only transitory. The extremes of
these differences may vary between 1500 meters (M. Javelle) and
6000 meters; that explains, without justifying them, the thought-
less denials which we have so often recorded.
Summary and Discussion 321
We should now apply ourselves particularly to the study of
influences of a transitory nature, and by analyzing, in a more
detailed manner, the narratives quoted find out whether it is
possible to explain these differences by certain conditions of envir-
onment, by circumstances in which the travellers are placed by
chance, or by this combination of intrinsic conditions peculiar to
each of us, some of which may be measured, others more or less
unknown and designated by the general expressions of constitution
and idiosyncracy. This is the place to investigate the effect of
habit and acclimatization and to take into account the race to
which the traveller belongs.
In this last connection, the results observed seem quite contra-
dictory: whereas d'Orbigny, Poeppig, Tschudi, de Saint-Cricq,
Weddell, the Grandidier brothers, etc., note with astonishment the
immunity of the Indians who run beside their mules without
showing the least distress, we find, in von Humboldt's ascent of
Chimborazo, a half-breed born in the lofty places suffering more
than the Europeans; likewise the peons of Caldcleugh, Brand, and
Steubel were sick when the travellers themselves felt almost no
effects; and yet, in a general way, it is clear that in the Andes the
Indians are much more resistant to the effects of mountain sickness
than the Europeans are.
I must quote in this connection a passage from an interesting
letter written me by a French engineer, M. E. Roy, former assistant
director of the School of Arts and Trades of Lima, who often
visited the lofty regions of the Andes:
The native Indian race is strong and vigorous; nature or the effect
of a kind of atavism has endowed it with a powerful respiratory
apparatus which permits it, probably by the respiration of a larger
quantity of air, to find the oxygen equivalent necessary for its exis-
tence and for the maintenance of a good constitution. The Indian of
these high plateaux is thick-set, with an enormous torso and pelvis
and relatively short legs; he is a walker of the first rank. Shod with
his double woolen socks and his moccasins, he will walk 50 kilo-
meters, without wincing, in his mountains and provided he has coca
leaves to chew, he will make this distance in one stretch. For him
and his llamas, a straight line is the shortest distance between two
points: he does not try to wind around the valleys to go from one to
another, he goes straight ahead, unless the mountain side is impassible;
that shows you how necessary it is that he should breathe freely.
Conversely, when these mountaineers go down to the seashore,
they cannot perform any hard work, as they do in their mountains;
many contract diseases of the lungs. At the school of which I was
assistant director, many of the young men coming from these lofty
regions had to return to their native air for this reason before finishing
their studies, because the work of the shop was too hard for them.
322 Historical
The opposite seems to be true in the narratives of travellers
in central Asia. Fraser complains bitterly of his coolies. Accord-
ing to Dr. Gerard (page 137), the inhabitants of Koonawur, born
on the lofty plateaux, are as sick as the travellers. Johnston relates
that whereas the natives who accompanied him on the peak of
Tazigand breathed with the greatest difficulty, he and his English
companions felt no ill effects (page 139) . Oliver Cheetam, Godwin
Austen, and Henderson tell similar experiences. To the Schlagin-
tweit brothers, the difference in races seems of little importance.
Drew saw a native of Punjab sick at 11,000 feet (3300 meters).
So Indians, even those born in mountainous regions, seem at least
as sensitive as Europeans to the effects of ascents.
The same is true in Africa in the ascents of the Kamarun
Mountains and Kilimandjaro; likewise in Hawaii on Mauna Loa,
the natives were attacked by mountain sickness before the
European travellers, and more severely than they.
But it should be stated at once that the natives and the Euro-
peans were not, during these journeys, in identical conditions,
either of clothing, or food, or exertion.
If natives belonging to races which seem, according to the
expression of Dr. Gerard, "born to live and die in inaccessible
regions", are attacked by mountain sickness, the same thing should
be true, for an even stronger reason, of the people of European
races living in lofty places. All the accounts of Chapter I show, in
fact, that the porters and the guides become ill as quickly and as
seriously as the travellers, when the latter have already become
used to exercise in the mountains. Sometimes even, the former
become ill first; the account of Dolomieu (page 71) is quite charac-
teristic. The slight advantage which they show, on the average,
is rather quickly acquired by people of the plains whom wander-
lust urges into the mountains.
Another proof, and that not the least striking, of the slight
importance of acclimatization in lofty places is drawn from the
intensity with which the disease attacks domestic animals. All
the accounts of travellers in the Andes and the Himalayas are
rich in melancholy details of the pitiful condition of the mules or
the horses which are carrying burdens; the latter often die; camels
are no better off; the mules of de Saussure uttered plaintive cries
on the glacier of Saint-Theodule; the wild cattle themselves, when
they are hunted, often vomit blood, von Humboldt says, and we
have seen what a sorry picture they made sometimes, according
to de Castelnau, in bull fights. Dogs are also severely attacked,
and have difficulty in running. Cats particularly seem to possess
Summary and Discussion 323
excessive susceptibility, since, according to Poeppig and Tschudi,
they cannot live above 4000 meters (pages 40, 46) . However, we
must note that, in the opinion of Tschudi and Elliotson, animals
born on the mountains are not as sick as the others.
But it must be admitted that all of this relates to imported
domestic animals. The' native species seem very comfortable at
the greatest heights; only Captain Webb saw yaks attacked by the
sickness (page 134); llamas seem completely immune, and in the
free state graze at altitudes of more than 4000 meters. Since the
time of Ulloa, everyone has been struck with astonishment at the
sight of condors soaring habitually at 4000 or 5000 meters, and
sometimes above 7000 meters; in the Himalayas, the lapwings and
other sparrows live at altitudes of more than 5000 meters.
Here we are dealing with one of the most interesting points
of this birdseye view of the subject. The influence of habit or
custom on mountain sickness is undeniable; but its conditions have
been both exaggerated and poorly determined.
On the testimony of d'Orbigny, Poeppig, Gay, Tschudi, and
Guilbert, one can become quite accustomed to living in the lofty
regions of the Andes, and the often unendurable distress which
attacks the European in the early part of his sojourn gradually
disappears. "In the streets", says Guilbert, "it is easy to distinguish
the newcomers; every forty or fifty steps they stop for a few
seconds" (page 54) . Analogous effects have been noted on our
European mountains; a novice who, when newly arrived from the
plains, is sick at a low altitude, can later make much higher ascents
with impunity. But we must not think that this immunity is
absolute; a fairly great change in level or peculiar circumstances
may suddenly bring on the sickness that had disappeared; we
shall find the proof of that in the accounts of M. Weddell, M.
Pissis and d'Orbigny himself. In a word, the same thing is true
of arrival in the mountains as of all sudden changes to which we
may be subjected; the passage of a certain time' permits the
reestablishment of the equilibrium which was shaken for an
instant, and which slower transitions would have left unaltered.
We shall try later to determine the nature and the importance
of the conditions changed by the act of ascent; but even now we
can assert the reality of habit or, as we usually say, acclimatization
to lofty places.
But here, as we cannot repeat too often, we are dealing only
with the violent and sudden symptoms of mountain sickness, in a
word; we have no intention of plunging into the delicate and com-
plex study (in which the means of demonstration are the more
324 Historical
numerous as they are less convincing) of real acclimatization, in
lofty regions, of successive generations tending towards the
formation of a race.
With certain reservations, for it seems to be proved that certain
persons cannot become accustomed to sojourn in lofty places, we
simply state that a traveller who has been in the mountains for
some time will feel no unusual sensations at a level where at first
he was ill; that his descendants, if he founds a family there, will
preserve his relative immunity; that the race thus formed will
enjoy the same advantages, so that the traveller who is a new-
comer will be surprised. But with the reservation already made
that there is nothing absolute in this.
We must also have an understanding in the matter of habit.
Indeed, as we shall say in a moment, fatigue plays a great part in
the intensity of mountain sickness. One of the consequences of
prolonged exercise in the mountains is a lessened tendency to
fatigue. The same thing is true of this special gymnastics as of all
others; one finally contracts only the muscles, only the muscular
bundles indispensable for the movement one seeks to make; one
brings them only to the degree of contraction which is precisely
necessary; in a word, one reduces the expenditure of energy to a
minimum. Moreover, the muscles, and no doubt the nerves also,
more frequently stimulated to action, from which a more active
local circulation constantly removes the wastes, can suffice for a
greater dynamic storage and expenditure, become, as we say,
stronger, and, for the same work, give the sensation of fatigue in
a much lessened degree.
And therefore one fits himself for acclimatization on the heights
by the simple gymnastic exercise of moderate ascents, with which
the professional "Alpinists" always take care to preface their
feats of lofty altitudes. For failure to comply with this rule, the
most energetic often pay a forfeit. One of the members of the
Austrian Alpine Club, very familiar with the lofty summits of
the Alps, who boasted to me that he had felt no symptoms on
Monte Rosa or Mont Blanc, confessed that he had been very ill
one day because he had made an ascent of 2500 meters, coming
from a sedentary life with no transition. That is one of the reasons
why the moderate mountains of the valley of Chamounix, Buet
and sometimes even Brevent (2525 meters) , cause illness in trav-
ellers coming from Geneva; it is also this lack of training which
explains the frequency of the symptoms of mountain sickness in
the ascent of Mont Blanc, when that of Monte Rosa is much less
feared in this regard; it is because the former ascent is often made
Summary and Discussion 325
by novices or even by "mountaineers" who have experience, but
who a few days before were living in the atmosphere of London
or Paris, whereas usually no one attempts Monte Rosa without a
series of preliminary exercises which have disciplined the loco-
motor apparatus.
Examples of the effect of fatigue are numerous in the very
accounts which we have quoted.
While listing the symptoms of mountain sickness, we must
dwell on the fact of its aggravation by exercise, even the most
moderate. Here, we should simply mention the cases in which it
appears only under the influence of fatigue, and we may even say
a passing fatigue, due to violent exercise. I myself have felt rather
serious symptoms because I climbed a hill about a kilometer long
at a quick step, on the road to the Grand Saint Bernard at an
elevation not above 1500 meters. It is to the effect of fatigue, of
burdens borne on the backs of men, that we should chiefly attri-
bute the violent symptoms which sometimes attack the peons of
the Andes and especially the coolies of the Himalayas Defore the
European travellers are affected.
The latter, moreover, usually allow themselves to be borne
quietly along on the backs of horses, mules, or yaks. We have
mentioned many cases in which the sickness attacked them sud-
denly, as soon as they dismounted to walk beside their animals.
If they are walking on difficult footing or on new snow into which
the body sinks, the fatigue is increased and with it the intensity of
the symptoms.
If, as travellers usually do, we apply the word fatigue not
only to the result of exaggerated muscular contractions but also
to the effect of other exhausting causes, this factor of mountain
sickness takes on still more importance. So insomnia and lack
of rest and comfort are not to be neglected. On their second ascent
of Mont Blanc, MM. Lortet and Marcet were much less ill than
on the first; they had passed a good night at the Grands-Mulets.
Most of the symptoms, when one is climbing this mountain, are
partially caused by the fact that the resting place, the hut of the
Grands-Mulets, is very poorly furnished; on the contrary, on Monte
Rosa there is the inn of the Riffelberg, where one rests comfort-
ably, and where one can stay several days at an elevation of 2570
meters.
To fatigue and insomnia we must add insufficient or poor food.
The guides are unanimous in urging one to eat little, but often
and substantially. A bad condition of the stomach or the intes-
tine infallibly brings on the symptoms long before the usual level.
326 Historical
Guides have frequently become ill at a fairly low level, because
they had been drunk the night before; peons who have bad
habits suffer more from the puna than the others, says Caldcleugh
(page 35).
The following are the principal circumstances, variable and
accidental, which may affect the intensity of mountain sickness:
lack of acclimatization, lack of training, fatigue, insomnia, poor
food, and temporary ill health. Different constitutions seem un-
evenly affected. According to most of the travellers, according to
A. Smith (page 44) , Tschudi (page 46) , Burmeister (page 52) , and
Pissis (page 56), the plethoric and also the aged or very weak
persons are especially affected. It is not rare to see persons appar-
ently frail, but bilious or nervous, make with impunity ascents on
which corpulent people fail. We may say that they have less
weight to carry, which is important, especially when they are
walking in the snow, into which they sink less; besides, their
pulmonary surface is, like that of children, greater in proportion
to their weight, but whatever the explanation is, the fact is com-
monly observed.
The state of ill health, for whatever cause, likewise predisposes
one to be sick sooner. "When I was not well", said Al. Gerard,
"I was sick at 13,000 feet, but in good health I felt no effects at
16,000 feet" (page 138).
An effect of general nature is that of cold, which predisposes
to mountain sickness. As we have seen, it usually appears in the
region of perpetual snow, and in intertropical lands it recedes with
the snow line to enormous heights. All travellers agree in declar-
ing that when the icy wind of high places rises, it makes the
symptoms unendurable, and may bring on death; this fact was
first noted in the Andes by Acosta (page 25) .
If then to the fatigue of walking and of burdens borne we add
insufficient food, the privations of poverty, and clothing insuffi-
cient to keep out the cold, we find united all the causes which may
increase the intensity of mountain sickness. These causes, not to
mention bad habits, combine to attack the unfortunate Indian
coolies and also, though to a less degree, the peons of the Andes;
that is enough to explain the violence with which they ordinarily
suffer from the puna or the bies, to use their expressions.
If now we refer to the differences mentioned at the beginning
of this section among the different mountains in regard to the
height at which the symptoms usually appear, we can explain
them in part by the observations which have just been abstracted.
If in' the tropics mountain sickness hardly ever appears below
Summary and Discussion 327
4500 meters, whereas in our Alps it is not rare a thousand meters
lower, temperature certainly has much to do with this considerable
irregularity; as I remarked a moment ago, the zone of eternal snow
is almost the same as that in which the symptoms appear. If the
city of Cerro de Pasco is so much dreaded by all travellers, that is
because its icy climate increases the severity of the symptoms
caused by the altitude. Evidently it is to their position on the
equator that the immense mountains which surround Quito owe i>
part the relative immunity enjoyed by the persons who ascend
them. At Quito, says Jameson,- the average temperature is about
14°; the thermometer fluctuates between 18° and 8°.
But this element is not the only one. There is a great differ-
ence, judging by what we said before, between a mountain situated
on the shore of the ocean, like the Peak of Teneriffe (3715 meters) ,
for example, and another of the same height in the main range of
our Alps, like Galenstock (3800 meters) . To make the ascent of
the former, in fact, the traveller starts from sea level, and in one
stretch covers a considerable vertical height; in the case of the
second, the distance to be traversed is lessened by at least 1000
meters. In the latter case, the transition is infinitely slower. More-
over, one cannot even approach the foot of the Alps without
having had a sort of acclimatization with muscular training, in-
stead of merely disembarking at the foot of the Peak or Etna.
And so on these mountains of moderate height, in spite of the
high temperature of their region, symptoms are still more fre-
quent than on mountains of similar height in the Alps.
For the same reason, in addition to their situation in the torrid
zone, Chimborazo, Antisana, Cotopaxi, etc. cause only moderate
symptoms; the city of Quito, which is at their feet, and from which
one starts after a longer or shorter sojourn, is situated at an alti-
tude of 2910 meters, so that there remains a vertical ascent of only
1950 meters to the summit of Pichincha; and so here we recall the
irreverent comparison of Canon Bourrit (page 13) .
The reader may convince himself, by reviewing the journeys
across the Andes (pages 22-59) , that the symptoms are much more
general and much more severe among travellers going from the
Pacific to the Atlantic, than among those going in the opposite
direction. In my opinion, the explanation of this apparent pecu-
liarity lies partly in the fact that from the coast of Chile the
ascent is extremely steep, whereas it is slow and progressive for
the traveller going from the east to the west.
The considerable height to which one must ascend in the Hima-
layas before being attacked by mountain sickness may be due to
328 Historical
the same cause. In the enormous range in which the Indus, the
Bramapoutra, and the Ganges rise, one reaches the dangerous
passes only after he has walked for a long time over hilly territory,
the strata of which, rising higher and higher, gradually prepare
him for the effects of the lofty heights. The transitions there are
very slow; the dreaded symptoms should appear very late, and
this actually happens.
But of course this great effect must be reconciled with climatic
conditions and other causes of variations which we have already
noted. It seems to us that, except for a few cases which are still
hard to interpret and upon which the discussion of theories sug-
gested will cast some light, the strange irregularities which we
mentioned at the beginning of this section can almost all be
explained satisfactorily.
2. Symptoms of Mountain Sickness.
Mountain sickness, the veta, puna, mareo, or soroche of the
South Americans, the bis, tunk, dum, mundara, seran, or ais of
the mountaineers of central Asia, the ikak of the natives of Borneo,
is composed, at its maximum intensity, of a group of dangerous
symptoms, which affect at the same time all the great physiologi-
cal functions: innervation, locomotion, circulation, respiration, and
digestion. We shall first summarize them in accordance with the
preceding accounts, assigning them to each of these divisions of
natural phenomena.
Digestion. Exaggerated thirst, distaste not only for eating, but
even for the sight and smell of food, lack of flavor in liquids,
nausea, and vomiting have been noted by almost all travellers.
One eats very little on lofty mountains; Martins and Bravais, with
three guides, made a good meal on the rations for one man. As
for violent symptoms, nothing is more striking than the descrip-
tion given by Acosta: "After vomiting food, phlegm, and bile, one
yellow and the other green, I even threw up blood" (page 24) . The
modest euphemism of English travellers about "heavings of the
diaphragm" and "distress in the stomach" give glimpses of the
picture energetically drawn by the old Jesuit. In the narratives
of the first chapter, we shall find it difficult to make a selection
among the many descriptions. Sometimes the stomach becomes so
sensitive that it cannot endure a spoonful of water (page 158) .
Diarrhea has been noted, probably as a result of the spurts
of bile injected into the intestine during the efforts to vomit. "My
companions were exhausted with vomiting and defecating", Acosta
Summary and Discussion 329
also says (page 24) . However we must say that in some cases it
seems to be due simply to the cold, to wet feet, etc.
The combination of these phenomena is always that which has
most astonished and terrified the travellers; to these phenomena
is due the old comparison which has given its significant name to
mountain sickness, mareo.
Secretions. Secretory disturbances are not very important;
their relation of effect to cause with the act of ascent is far from
demonstrated. If there is an exaggerated flow of perspiration, the
violent exercise and the direct action of the rays of the sun are
sufficient explanation for that. The decrease in urinary secretion
may be the consequence of the same causes, but several travellers
see in it the direct effect of lofty regions. Besides, no exact meas-
urement has been taken, nor has any chemical analysis been made.
Respiration. Respiration which is more frequent, shorter, then
difficult, broken, and uneasy has been experienced and noted by
everyone. Oppression is often accompanied by pains in the chest.
This, along with exaggerated fatigue, is the first manifestation of
mountain sickness. Animals are not immune. We have seen what
importance has been attached to the increased respiratory rate by
the theorists who have considered the question; we shall return to
it in a moment.
The observations of M. Lortet (page 111) have fixed the modi-
fications in the respiratory rhythm caused by the altitude: the
amplitude decreases if the number increases. Vivenot in his appa-
ratuses has also noted this (page 280) .
As to the consequences, in regard to respiration, of a permanent
sojourn in lofty places, the data reported seem to contradict these
results. To quote only the most recent authors, M. Jaccoud states
that the number and the amplitude of the respirations increase on
the Engadine (page 297) . Drew also finds "the respiration more
rapid and more ample" (page 295) . M. Armieux reaches the same
result in regard to number; moreover, he reports an increased
respiratory capacity in the hospital attendants at Bareges. Every-
one seems to agree on the question of frequency; but that of
amplitude requires additional research. The same thing is true,
for greater reason, if we take up the question of races (page 301).
Circulation. The acceleration of the pulse, though it has not
been noted by all travellers, like the digestive and respiratory
disturbances, is no less constant. One can verify this, even though
no feeling of discomfort attracts the attention. While I was making
the very modest ascent of Nivolet (1558 meters) near Chambery
(269 meters) , my pulse rate and that of all the other persons who
330 Historical
composed our little caravan rose by 4 to 8; it was counted, of
course, after a long rest. Lieutenant Wood only by chance noticed
the extraordinary rapidity of his pulse, so that he thought he was
feverish (page 143) .
When the difference in level is very great, the acceleration
becomes considerable. Moreover it is, as de Saussure said (page
85) , in proportion to the intensity of the distress experienced. The
extraordinary rates of 130 and 140 are not very rare on lofty moun-
tains: "My heart", says Mistress Hervey, "was going a railroad
pace" (page 149) . Parrot tried to establish a sort of ratio, which
might have served as a measure of the height, between his pulse
rate and the altitude reached (page 122). The table published by
Lortet (page 114) is very interesting in this regard; but such a
regularity is far from being general. At great heights, the acceler-
ation of the pulse becomes unendurable; it is accompanied by
buzzing in the ears, throbbing in the carotids and temples, and
more or less violent palpitations which become terrifying. This
acceleration does not seem to be controlled by the use of digi-
talis (page 151).
This modification is not transitory; it continues through the
whole sojourn in lofty places. It is regrettable that exact obser-
vations on this point are extremely rare. So I think I should quote
here those which were recently published by M. Mermod.
M. Mermod" counted his own pulse rate repeatedly at the
three stopping places of Erlangen (323 meters), Lausanne (614
meters), and Sainte-Croix (1090 meters); the sojourn in each ot
these places lasted several months. These observations were made
with meticulous care, and all necessary precautions were taken so
that the causes of error might be less than the variations, evi-
dently very slight, which the circulation might show under equally
slight differences in altitude. The average of 900 observations
made at Erlangen was 62.76 heart beats, that of 577 observations
made at Lausanne was 66.68, and that of 333 observations at Sainte-
Croix 68.87. The increase of the number with the altitude was
noted at all hours of the day.
M. Jaccoud (see page 297) also observed on the Engadine a per-
sistent acceleration of his own pulse rate.
I should, however, mention on the opposite side the observ-
ations of Dr. Armieux (page 299) , who found an average decrease
of 3.85 heart beats from Toulouse (200 meters) at Bareges (1270
meters) .
The frequency does not show the only modification in the pulse.
Its strength is greatly diminished, it becomes irregular, very
Summary and Discussion 331
plainly dicrotic, and is progressively smaller and more easily de-
pressed. The tracings made by M. Lortet during the ascent of
Mont Blanc (see page 112) are very clear in this regard. The
arterial tension decreases considerably.
Other observers, on the contrary, have found the pulse full,
strong, "vibrating," says Guilbert, "as in aortic insufficiency" (see
page 54) . According to Junod, who experimented in closed vessels,
it is full, depressible, frequent (page 229) . Without losing strength,
says M. Lepileur, the pulse increases in rapidity considerably
(page 236).
The venous system displays no less striking phenomena; full-
ness of the blood vessels, congestion of the skin, the lips, and the
conjunctiva; face violet or reddish, swollen; lips blue and swollen.
Then sometimes the picture suddenly changes completely; the
face becomes pale; syncope seems imminent. Sometimes it actually
appears, going as far as complete loss of consciousness. Upright
posture is very likely to bring it on (see pages 79, 106) .
The most terrifying, if not the most serious, of the circulatory
disturbances is hemorrhage; it appears less frequently than is
generally said; in order of frequency, we note first nasal and pul-
monary hemorrhages, then hemorrhages from the eyes, the lips,
the ears, and the intestines; finally, M. Martins experienced a
slight hematuria. Mile. Dangeville found that her menstrual period
was considerably advanced; but the violent exercise might explain
that.
These losses of blood have been observed in animals, especially
horses and cattle. I mention in passing the important observation
of Dr. Clark, who remarked that the blood coming from the nose
was "darker than usual" (page 91).
Locomotion. The heaviness of the lower limbs, the "blow on
the knees", a fatigue which the efforts made do not explain, are
among the first signs of mountain sickness. We have seen in
numerous quotations that at a certain height it becomes impossible
for the sturdiest walkers to take more than a few steps without
stopping. And this is a matter of altitude, not of the ordinary
difficulties of mountain journeys. "I made 34 miles on foot," says
Captain Gerard, "through country which would be called moun-
tainous by those who do not know the difficult parts of Koonawur,
more easily and quickly than I could walk 12 miles in these lofty
regions. When the altitude is more than 14,000 feet, every mile,
even when the road is good, requires at least twice as much time as
at the height of 7000 to 8000 feet" (see page 138) .
332 Historical
It is not only walking that becomes painful. The slightest
weight wearies the shoulders; a task, moderate in ordinary regions,
cannot be carried out in the mountains without real sufferings,
sometimes dangers. "We could not use our arms," said Dr. Gerard
(page 136) , "to break off a piece of rock with a stroke of the ham*
mer." Hamel says that "even talking tires one" (page 90) . And the
Schlagintweit brothers, who make the same observation, add that
"one heeds neither comfort nor danger" (page 155) .
I have found convulsions mentioned only in the narratives of
Mistress Hervey (page 147) and, in spite of the disrespect of the
connection, in the horses whose story is reported by Liguistin
(page 272) . But in both cases there is perhaps some other cause in
addition to the effect of lofty places.
Innervation. At the head of this category come the headaches,
which are so violent and unendurable, compared to "an iron ring
compressing the temples" (Guilbert), as if "the head were going
to split in two" (Mrs. Hervey), of which travellers in the Himal-
ayas complain in particular.
The sensory modifications, and especially the mental depression,
have been noticed much less than the preceding symptoms. How-
ever, rather frequent mention is made of buzzing in the ears and
a blunting of hearing and taste. The weakening of hearing is
explained by the lessened intensity of noises transmitted by the
thin air. Mention is more rarely made of sight, although we have
quoted examples of travellers whose sight failed or who com-
plained of dazzled or dimmed vision, etc. (see pages 94, 147) . Loss
of consciousness, total swooning as a result of syncope, they say,
is also mentioned. But only an unwilling report is given of what
Captain Gerard frankly called "mental depression" (page 138),
and Henderson called "great prostration of body and mind" (page
158).
And yet when we read travellers' accounts carefully, we almost
always find the manifest trace of it. Many disguise it under the
name of drowsiness; there is no hesitancy about speaking openly of
a desire to sleep which sometimes becomes unconquerable; but
we do not admit so willingly that the senses are dulled, the intel-
lect weakened, the energy lessened, that the mind like the body is
invaded by extreme indolence, or, by a strange reaction, thrown
into unhealthy exaggerations.
Count de Forbin, however, declares (page 72) that he was
"enfeebled, agitated by the terrors of a feverish brain. Weariness
of the senses, exaltation of the imagination cast one into a state
of near-delirium." Henderson also speaks, and de Saussure had
Summary and Discussion 333
done the same long before him, of a great excitability of temper.
On the other hand, de Saussure admits that he did not work with
much zest on the summit of Mont Blanc. M. Lepileur goes further
and relates (page 103) that he and his companions journeyed me-
chanically, without thinking, so to speak, He attributes to this
mental prostration the contradictions which he notes in the
accounts of mountain climbers who preceded him. As for me, who
have read hundreds of accounts of ascents, in the collections of
Alpine clubs of all nations, I cannot help thinking that their mon-
otony, their lack of real interest, the want of more than average
thoughts which characterizes almost all of them, result largely
from the unconscious state of mental depression of their authors,
caused by the sojourn in lofty places. The average account of
ascents to lower levels is infinitely more interesting, richer in out-
side observations and evidences of intellectual activity; gymnastic
feats and culinary preoccupations are much less in evidence in
all cases.
Aeronauts have noted similar facts, that is, slow depression
leading to indifference and sleep: "The mental powers fail before
the physical powers. First one loses memory and care. He forgets
to give heed to the balloon; soon a slow and gentle sleep lulls all
the members" (Robertson, page 183). In other cases, there is a
strange excitement. Finally, at great heights, the aeronaut, even
in the most complete physical calm, is suddenly struck by complete
insensibility. That happens to Zambeccari and M. Glaisher.
Such are the grievous symptoms produced by the influence of
lofty places. At the beginning, a sensation of inexplicable fatigue,
short respiration, rapid panting, violent and hasty palpitations;
distaste for food; then, buzzing in the ears, respiratory distress,
dizziness, vertigo, weakness constantly increasing, nausea, vomit-
ing, drowsiness; finally, prostration, dimming of the vision, various
hemorrhages, diarrhea, and loss of consciousness. Such is the as-
cending series of symptoms, in proportion to the altitude reached.
Among all the accounts which we have collected, which picture
vividly all these distresses, in my opinion, there is none which is
more vivid and complete than that of Tschudi, falling unconscious
on the ground, in the icy Puna of Peru (see page 47) .
Even death, an immediate death, may be the result of these
serious symptoms. We have given some instances of this in the
Andes (see pages 25, 33, 37, 43) and in the Himalayas (page 137).
And it is not only men who may succumb; animals, cats, dogs,
camels, mules and horses in particular, die still oftener.
The intensity of these symptoms is considerably aggravated
334 Historical
by walking, running, any expenditure of energy. We have had
many examples of this: one of the best guides of the Oberland
(page 94), whom a rather strenuous effort twice makes blind; the
traveller Weddell, till then immune to the soroche, who is stricken
after a rapid excursion (page 48) ; de la Touanne, falling on the
ground almost unconscious, because he wished to go faster sud-
denly (page 36) ; d'Orbigny, who, thinking himself acclimated,
was compelled to stop every time he waltzed (page 38) ; Hedringer
falling on the snow, because he wished to run to the summit of
Mont Blanc (page 96) ; an inhabitant of the Alpine mountains, who,
trying to outstrip his companions, rolls over "as if some one had
shot him" (page 116). Travellers say that it is to the eagerness of
the horses, which spring forward under the spur, that their fre-
quent deaths are due, whereas the mules, patient and obstinate,
survive because they refuse to quicken their pace. It is walking
uphill which especially fatigues and exhausts.
This fatal effect of muscular activity is felt at all altitudes. But
in regions of moderate elevation rest is sufficient to dissipate its
effects and restore complete calmness. And that is perhaps the
most peculiar characteristic -of mountain sickness. To the uneasi-
ness of the traveller, to his extreme fatigue, to his grievous dis-
tress, there succeeds an unexpected comfort, as soon as he stops,
sits down, or particularly lies down: his heart regains its rhyfhm,
respiration becomes regular, a feeling of energy returns, all as if
by enchantment; so that after a few minutes, astonished both by
these unknown discomforts and this sudden cure, the inexpe-
rienced traveller confidently resumes his climbing. But soon he is
again attacked and conquered.
On loftier mountains, rest, even rest in a horizontal position,
even if it dissipates the most violent symptoms, does not, however,
restore calmness. Palpitations, suffocations, trouble or prevent
sleep. Sometimes a strange symptom appears; during the night,
at dawn especially, sudden respiratory distress awakens the sleeper
with a start (see pages 39, 54, 55, 132, 149, 155, 158, 160) . A few deep
inspirations restore calmness; probably it is a consequence of this
forgetting to breathe of which de Saussure had spoken (page 83) ;
imminent asphyxia awakens the sleeper suddenly.
Such is the series of symptoms which, in different degrees, at
different altitudes, attack mountain climbers and aeronauts. It
seems that there is no great difference, except in intensity, be-
tween the symptoms observed in the different mountainous
regions. Although the symptoms which we have described appear
sooner in our Alps than in the Andes and the Himalayas, they
Summary and Discussion 335
never reach there the dangerous severity which threatens the
lives of travellers and their guides, even natives, in the other
regions. That is because the height of Mont Blanc (4810 meters)
is the maximum which one can reach in our Europe, and because
one remains there only a few hours at the most. Conditions in the
Himalayas are far different, because there one remains for a long
time on plateaux at an altitude of more than 4000 meters, crossing
almost every day passes which reach an elevation of 5000 to 5500
meters.
A harmful influence whose dangerous effects many travellers
have mentioned is that of the wind. "There blows in this place,"
says Acosta, whom I must constantly quote, "a little wind which
is not too strong or violent. But it is so penetrating that men fall
dead from it, almost without perceiving it" (page 25) . M. Lepileur
also suffered from the wind to a much less dangerous degree (page
103). The Schlagintweit brothers also complain of it very bitterly
(page 155) , and Henderson claims that it often kills travellers
(page 159).
Many narratives agree in stating that the symptoms are parti-
cularly severe at points on the mountain where the air is renewed
with greater difficulty. Should this irregularity be attributed to
the heating of this air, expanded by the sun? Or to the tediousness
of walking in these monotonous passages? The observations of
M. Javelle and M. Forel tend to support this latter hypothesis.
They state, in fact, that mountain sickness disappears in dangerous
spots (page 289) and also as a result of attentive observation of
the landscape or oneself (page 292) .
It would not be very interesting to dwell on the medications
used by the natives against the symptoms of mountain sickness.
They generally agree in forbidding alcoholic beverages; in
America, they praise bleeding, especially for animals. In the Andes
protective powers are attributed to garlic or onion placed in the
nostrils of the animals; in the Himalayas, acid and dried fruits are
used. Almost everywhere it is recommended that one should eat
little and often. M. Dufour declares that he dispelled an already
violent attack of mountain sickness merely by eating a piece of
bread (page 290).
3. Theoretical Explanations.
We may divide into two great categories the hypotheses and
the theories put forward to explain mountain sickness: some of
them, by far the most interesting, try to settle the mechanical,
physical, or chemical role of the diminished atmospheric pressure;
336 Historical
the others, the most peculiar ones, seek the cause of the symptoms
in something other than the fall of the barometer. We shall begin
with the latter.
Pestilential exhalations. The explanations which put forward
pestilential exhalations, either from the ground or from toxic
plants, must be given a moment of our time.
They have their origin in the absolute ignorance of the native
peoples about the very existence of an atmosphere. Therefore the
Indians and the Tartars of the Himalayas, the Redskins of the
Andes and their successors, almost as uncivilized as they, did not
hesitate to attribute the symptoms which struck them and their
domestic animals to some mysterious poisoning. In the Andes, the
frequent presence of metallic ores and the evident effect of moun-
tain sickness upon the unfortunate miners gave rise to the belief
that there issued from buried metals, and particularly from anti-
mony, "which plays," says Tschudi, "an important part in their
physics and metallurgy," emanations dangerous to all those who
passed over their veins. Hence the name soroche, which means
both antimony and mountain sickness.
In central Asia, the idea of exhalations from the earth also
occurred to the people, especially towards China; we saw that
Father Hue did not hesitate, with his usual credulity, to declare
that the symptoms of Bourhan-Bota were due to carbonic acid
from the ground (page 238) .
Volcanic mountains, like Etna, the Peak of Teneriffe, the moun-
tains of North America, because of deleterious vapors which rise
from certain crevasses, have caused among travellers a much more
pardonable confusion between the effect of the altitude and that
of the mephitic gases; we have seen examples of it.
All through the Himalayas, the mountaineers do not hesitate
to attribute the distress from which they suffer to volatile poisons
emanating from flowers or plants. Generally the narratives of the
travellers limit themselves to these vague expressions; but when
they are more exact, the strangest divergences appear.
The Chinese author whom we quoted (page 129) gives rhubarb
as the cause. When Fraser's coolies complain of the seran and
blame the flowers which cover the ground, he looks around him
and finds primroses, heather, and polyanthus (page 132) . For Mis-
tress Hervey, whose distress we have narrated, it is a sort of moss,
the boottee, which the natives show her as the cause of all her
troubles (page 148) . They could not show Cheetam the dewaighas,
the mysterious and toxic plant (page 153) . Henderson reports that
they blamed artemisia (page 295) , and Drew, the onion (page 295) .
Summary and Discussion 337
These hypotheses, natural product of the ignorance of the
natives, have sometimes been accepted by European travellers.
They served as an easy explanation of this curious fact that the
intensity of the symptoms is not regularly proportional to the alti-
tude, and that at certain points, sometimes of moderate elevation,
almost everyone is sick. It is especially travellers in the Andes
who believe in emanations from the ground. Some of them would
say, like the peons of Brand: "There is much puna here" (page 36) .
However, very few admit their credulity clearly; they are satis-
fied with saying that there are "accompanying causes, which are
unknown, and which act with the rarefaction of the air" (page 55) ;
that "the atmospheric pressure is not included in the causes of the
soroche, which should perhaps be attributed to emanations from
the ground" (page 58) .
Asiatic travellers have been more prudent. Hodgson alone
allows one to glimpse a certain credulity (page 223) ; but all the
others refuse to admit intoxication by plants; those who have
deigned to take note of it declare formally that frequently the
symptoms appear where there is no vegetation, not even moss:
from Fraser to Mistress Hervey and Drew, they all agree on this
point.
To tell the truth, these hypotheses do not need any other refu-
tation. Moreover, the identity of the morbid symptoms attributed
now to antimony, now to vapors from the earth, elsewhere to
emanations from undetermined plants, is enough to show that
they have a single cause, which is closely connected with the ele-
vation above sea level.
Electricity. When. people do not know what else to say, they
are very likely to invoke electricity as the cause. Dr. Govan did
this (page 221) : "These phenomena," he says, "depend upon atmos-
pheric circumstances, less general than the decrease in pressure,
like the electric power which must be in a state of constant fluct-
uation in the presence of such lofty conductors." For Heusinger
(page 245) , electricity must act, for it is stronger and less often
negative. But these authors were outdone by Dr. Cunningham,
who declared that "in the northern hemisphere, the electricity
attracts the blood to the head, and in the southern hemisphere, to
the feet .... from which mountain sickness results, which explains
why this illness is cured by the horizontal position" (page 225) . The
strangest thing is that this strange doctrine has found votaries
(page 296) .
Lack of oxygen in the air. It is the unevenness of the effect of
the altitude, according to the regions, which has suggested all these
338 Historical
peculiar explanations. Truthworthy, even eminent men have not
escaped this need of seeking elsewhere than in the effect of dimin-
ished pressure the cause of the distress experienced.
Certain persons believed that they had found this cause in a
special weakening of the air or, to speak more exactly, in its
diminished oxygen content. That was the opinion of von Hum-
boldt (page 30), who said that he found only 20% of oxygen on
Chimborazo, and attributed a great effect to this difference.
M. Boussingault, struck by the fact that mountain sickness
hardly ever occurs until perpetual snow has been reached, took
up an old idea of de Saussure, who had maintained that the air
released from the pores of the snow contains less oxygen than free
air; he made an analysis which gave only 16% of oxygen, and then
he attributed the suffocation which he had experienced to this
foul air. freed by the action of the solar rays (page 227) . By this
reckoning, one should experience mountain sickness on plains
covered with snow, in a fine January sun. Other travellers (page
294), without other objection, accepted this hypothesis, which the
celebrated chemist himself finally admitted was mistaken.
Fatigue, cold. These are two causes frequently hailed, not as
adjuvants, which would be correct, but as the principal or. even
the sole cause. It is the warhorse of those who deny mountain
sickness: "We can assert," says one of them, "that these are the
same sensations experienced by ordinary travellers when they
approach the summit of any mountain" (page 231). "What proves
indisputably that these symptoms are due to fatigue," says
Bouguer, "is that no one was ever affected by them when he was
on horseback, or when he had once reached the summit, where
the air, however, was still thinner" (page 208) .
We must admit that at first glance and for slight symptoms
confusion is possible. Hasty respiration, dyspnea, circulatory accel-
eration, palpitations, even vertigo, and heaviness of the limbs are
the result of any exercise which is somewhat tiring and prolonged.
But we need only glance at the numerous data reported above to
find in them the proof that there really is a special influence in
lofty places: the symptoms appear, as we have seen, even during
rest and sleep. Moreover, Acosta had very early refuted these
errors (page 24), as did de Saussure (pages 213, 216).
Yet it is still fatigue, though of a special type, which Rey
invokes (page 232). M. Lepileur's ideas (page 237) are evi-
dently of the same sort; this learned physician in his explanation
of the fatigue gives overwhelming importance to "the congestion
Summary and Discussion 339
of blood taking place in the muscles during their action." As to
the other phenomena, they are the result of congestions of the
lungs or the brain, caused by the constant repetition of efforts
made during the act of climbing. Moreover, "the rarefaction of
the air, making respiration more frequent and panting more rapid,
necessarily hastens the rest of the ordinary effects of effort." But
how does the rarefaction of the air make panting more rapid? That
is what M. Lepileur does not tell us.
Theories of M. Lortet and M. Dujour. Here now are two very
important theories, which show a thorough knowledge of the most
difficult questions of physiology. Their place is indicated here
because they are, in a word, only a scientific form of the common
charges against fatigue and cold.
In the opinion of M. Lortet, the body temperature of man
diminishes when he expends the enormous quantity of work nec-
essary to raise the weight of his body to a great height. We have
reported in full the data secured by Lortet (page 114) and the
theoretical conclusions which he draws from them (page 286) . Un-
fortunately, as MM. Forel (page 288) and Clifford-Allbutt (page
289) have shown, the very observations of the French physiologist
were wrong: the temperature of the body always rises as a result
of the act of ascent, as in the case of all violent gymnastics.
Even referring to the figures of M. Lortet, who maintains that
from Chamounix to the Grands-Mulets the temperature dropped
2°, and that at Chamounix the act of walking cooled the body 1.7°,
serious symptoms should follow the slightest exercise at these
elevations, where, however, mountain sickness has never been
observed. Moreover, according to him, rest should restore the
normal temperature almost instantaneously but it is far from dis-
pelling all the symptoms.
We must say, however, that M. Forel, never having had moun-
tain sickness, could not take his temperature in this special
condition; we might still say, until proved wrong, that he would
find it lowered in this case. But even if it v/ere so, it would still
have to be admitted that another element besides work must be
involved, and that altitude is this element.
We shall soon discuss the theories about insufficient oxygen-
ation due to decreased pressure. If we introduced this new factor
into Lortet's theory, we should be led to think that since the work
of ascent requires an increased combustion, and since the propor-
tion of oxygen is too small, heat would be transformed into motion,
resulting in a drop of temperature and consequently, general dis-
turbances. But this drop would have to be proved, and Lortet's
340 Historical
observations are evidently tainted with causes of error which
vitiate them as sources of proof: even the experiments of Legallois
(page 218) , notable as they are, cannot be used in his favor, since
they deal with confined air.
The theory of M. Dufour (page 291) is also independent of the
idea of altitude. In his opinion, mountain sickness is the conse-
quence pure and simple of fatigue, which results from the
exhaustion of the ternary materials stored in the muscles; and so
he states that he experienced the symptoms even on the plain,
after great fatigue. It cannot be merely the rarefaction of the air,
he says, which makes one ill on the summit of Mont Blanc, be-
cause aeronauts had to reach 7000 and 8000 meters to experience
serious disturbances; moreover, these disturbances do not at all
resemble those produced on the mountain.
We leave to the reader the task of weighing the value of this
last statement, and as for the comparison of mountain sickness to
simple fatigue, we shall merely ask why it has never been made
by tourists, who, not without great fatigue, walk all day in
mountains less than 2000 meters high. At least they have never
confused the lasting weariness which they experience in the eve-
ning with the sudden "blow on the knees" which exhausts the limbs
and disappears after a few minutes rest; nor have they confused
the breathlessness and the acceleration of the pulse due to a la-
borious or rapid walk with the dyspnea, the palpitations, and the
total exhaustion which, at an elevation of 4000 meters, often halts
the traveller after a few steps. There is, therefore, something be-
sides the exhaustion of the ternary materials, and this something
is the altitude reached, or, to speak more clearly, the diminished
pressure. This objection is evidently applied to the ideas of Bou-
guer, Lepileur, and Lortet, as well as to the theory of Dufour.
We now come to the theories which involve the decrease in at-
mospheric pressure. Laboratory experiments had shown that ani-
mals placed under the bell of the pneumatic machine became ill,
even died, when the pressure was lowered sufficiently, and the con-
clusion had been drawn that the lowered air pressure on lofty
mountains was probably the chief cause of the symptoms. But
how does it act? Here the theories become numerous.
Decrease of the iveight sustained by the body. One of the first
which entered the minds of travellers may be summarized thus:
At normal pressure, each square centimeter of our bodies sustains
a weight of 1.03 kilograms, or, for the entire surface, a number
which should be 18,000 kilograms for a man of average height.
We do not feel this enormous weight which would crush us, the
Summary and Discussion 341
authors say, thanks to the inner tension of the fluids of the body
which counteract it; but if it diminishes, immediately this tension,
which nothing now checks, will urge the fluids to the periphery,
will fill the skin with blood, will swell it, will congest it, and by
rupturing the blood vessels will cause hemorrhages: it will be the
same as if the body were plunged into an immense cupping-glass.
Now this is what happens when one rises in the air: at an eleva-
tion of 3300 meters, 5000 kilograms will have been removed; at
5500 meters, half of the total weight, that is, 9000 kilograms. Why
should one be surprised at the serious disturbances which occur
then?
This is the theory approved by the large majority of those who
have considered the question, particularly, 'we must say, travellers
and physicians. We find it suggested for the first time in a few
words by Bouguer (page 209) . Haller develops it at length (page
210) ; it is true that, recalling a strange idea of Cigna (page 206) ,
he declared that there is a great difference between "air rarified
by the removal of a part of it and that which is lighter because
of the elevation. . . In the latter, although it has lost half its weight,
respiration takes place without difficulty." That is no stranger,
at any rate, than to see Bourrit maintain that at an equal elevation,
"the air of the Alps is rarer than that of the Cordilleras" page
213) . De Saussure accepted completely the theory of the "relaxing
of the vessels produced by the decrease of the compressing force
of the air" (page 215) . It was this illustrious physicist who ex-
pressed it most clearly. It was also accepted by Fodere (page 217),
Halle and Nysten (page 217), Gondret (page 220), Dr. Gerard
(page 222), Hipp. Cloquet (page 223), Burdach (page 225), Rey
(page 231), Brachet (page 235), Lombard (page 243), Heusinger
(page 245) , Foley (page 270) , Scoutetten (page 276) ; we mention
only the chief advocates.
We see that this theory has the support of the most eminent
names. It is really painful to have to reject it by a sort of pre-
liminary question, as absolutely contrary to the laws of elementary
physics. But long before me, MM. Giraud-Teulon (page 246) and
Gavarret (page 279) had called upon the principle of the incom-
pressibility of liquids to combat this error. Valentin (page 244) had
even calculated that the removal of a half-atmosphere would
increase the volume of the body only about three hundred-thou-
sandths. It is quite evident that all pressures or decompressions
balance each other, immediately counteract each other, when they
are applied to the whole body, since it is composed entirely of
342 Historical
liquids and solids. If there is decreased pressure on the surface
of the skin, on the outer wall of the blood vessels, the decrease is
absolutely equal on their inner wall, and there is no change in
the state of equilibrium.
It is really strange that anyone could have thought seriously
that by going to Cauterets he would be relieved of 2744 kilograms
(page 276), and that Gay-Lussac should have felt 10,000 kilograms
removed from his shoulders in a few minutes. If the liquids of
the organism were really thus held by the outer pressure, a few
centimeters decrease in pressure would produce the most terrible
disturbances. It is the comparison with the cupping-glass which
has caused the error: they forgot that in the cupping-glass it is
the effect of the pressure on the rest of the body which causes
the swelling, the congestion, and the local hemorrhages.
Escape of the gases of the blood. The physicists, most of whom
escaped the erroneous hypothesis which we have just discussed,
were better inspired when they gave an important role to the
escape of the gases of the blood, as an effect of the diminished
pressure. Robert Boyle had been the first (page 201) to see that
all the liquids of the body, blood, urine, bile, humors of the eye,
release bubbles of gas, when they are placed in the vacuum. From
it he drew the conclusion that in animals which die under these
conditions, death may be, "besides the failure of respiration," the
result of the formation of these bubbles, which "check or disturb
the circulation in a thousand ways." He even thought that, at
the time of slight variations of the barometer, it is "the spirituous
or airy particles which, held in abundance in the blood as a whole,
naturally expand the liquid, thus being able to distend the large
vessels and change considerably the speed of the circulation of
the blood in the capillaries and the veins."
Borelli had the same idea and attributed to a sort of effer-
vescence of the blood the symptoms which he had experienced on
Mount Etna (page 207) ; but he soon gave up this idea (page 208) ,
to which, however, there rallied Musschenbroeck (page 198),
author of a dissertation De aeris existentia in omnibus animalium
humoribus, Veratti (page 204), Rostan (page 225), F. Hoppe, who
made experiments upon animals to verify it (page 248), Guilbert
(page 254) , and finally Gavarret (page 279) .
The escape or the tendency to escape of the gases of the blood
has been used especially to explain the circulatory acceleration
and the hemorrhages. "When the outer pressure diminishes," says
M. Gavarret, "these gases tend to escape from the blood, force the
walls of the vessels from within outward and distend the pul-
Summary and Discussion 343
monary and general capillaries, the walls of which, since they are
thin and lack resistance, may be ruptured. Such is the mechanism
of the production of hemorrhages."
Indeed it seems settled, in spite of the objections of Ch. Darwin
(page 207), John Davy (page 224), and M. Giraud-Teulon (page
246), that at a sufficiently low pressure, gases escape from the
blood of living animals placed under the pneumatic bell; F. Hoppe
did not even hesitate to conclude that the death of the animals
under these conditions is due to this release of gases. But noth-
ing in the experiments yet known proves that the escape takes
place at pressures which coincide with mountain sickness, nor that
the tendency to escape can bring on the disturbances for which it
is blamed. No comparison can be made between an animal brought
in a few minutes to a fatal decompression and a traveller who
takes six hours to ascend vertically 2000 meters. If the gases were
partial cause of the symptoms, aeronauts, who undergo enormous
changes in pressure with great rapidity, would be the first to be
stricken, and we know that that is not the case.
Expansion of intestinal gases. The idea that the decrease of
pressure must expand the intestinal gases is evidently not wrong
from the standpoint of physics; but that is far from justifying the
conclusion that this increase in volume is the cause or one of the
causes of mountain sickness. However, Clissold (page 224) con-
sidered that it must hamper respiration and circulation consider-
ably. M. Lepileur (page 237) and Speer (page 241) also tend to
attribute some effect to it; M. Maissiat is more positive: "The in-
testinal gases, gaining volume, distend all, to the point of rupture"
(page 234) . The learned physicist reasoned as if the intestine was
a closed swimming bladder, and he forgot the double communica-
tion with the exterior, which, in practice, permits no distention.
The same thing is true of M. Colin, who sees a cause of death in
"the forcing back of the diaphragm by the expansion of the gas"
(page 307) .
Loosening of the coxo-femoral articulation. It is under the
patronage of the illustrious von Humboldt (page 228) that there
appeared this odd explanation of the extreme fatigue and the
heaviness of the lower limbs which appear in lofty ascents. It
has since been accepted by many writers: Tschudi (page 232),
Meyer-Ahrens (page 243), Lombard (page 252), and Guilbert
(page 255) .
It is undeniable, as B6rard (page 312) has shown, that the sur-
face of the cotyloid cavity is sufficient to permit the atmospheric
pressure to support the weight of the leg, when all the soft parts
344 Historical
have been cut away. According to M. Jourdanet, the pressure
thus exerted would be equivalent to about 23 kilograms. We have
seen how this author proved, by calculations based on the surface
of the cotyloid cavity, that at the time when the weariness of the
lower limb appears, the atmospheric pressure is still capable of
supporting a weight double that of this member (page 257) .
Dr. Faraboeuf, at my request, consented to make precise meas-
urements upon a human cadaver. Here are the results which he
gave me:
Man of forty-eight years, weighing 52.5 kilograms; height 1.65
meters, 0.85 meters in the lower limb; well proportioned, thin, but
still apparently muscular.
Diameter of the cotyloid cavity 51.5 mm.
Surface 20.8 sq. cm.
Weight of the atmosphere on this surface 21.4 k.
Weight of the lower limb disarticulated
in the fold of the buttock and the groin 6.3 k.
Weight of the lower limb deprived of the muscles
which are inserted into the pelvis 5. k.
So the atmospheric pressure is capable by itself of supporting
a weight four times greater than that of the lower limb deprived
of the muscles which support themselves by their connection to
the pelvis. We should therefore have to go to a fourth of an at-
mosphere, that is, a pressure of 19 cm. to cancel the support fur-
nished by the weight of the air. Evidently then the cause sug-
gested by von Humboldt has no connection with the fatigue which
appears on Mont Blanc at a pressure of 41 cm., at which point the
atmosphere still represents 11.5 kilograms.
Very certainly the effect of the pressure upon the firmness of
the articulations has been exaggerated; setting aside this exaggera-
tion, von Humboldt has not drawn the really logical conclusion
from the principle which he thought correct. It is not a greater
muscular fatigue which should occur, and it should not be limited
to the muscles of the thigh; the danger for the traveller in regions
where the atmospheric pressure is lessened is dislocations, and in
all the articulations; but in spite of the unusual exertions which
ascents entail, no such symptom has ever been noted.
Other mechanical effects of decreased pressure. Borelli at-
tributed the fatigue to the presence in the thorax of expanded air
which "no longer aids," he says, "the effort of the muscles, com-
pressing by its elasticity the air and blood vessels." It is not easy
to see clearly what the learned physician-mathematician meant.
But there is some truth in what we may suppose to have been his
thought. If, in the phenomenon of effort, the chest walls, as M. J.
Summary and Discussion 345
Cloquet 4 has shown, are immobilized in a certain state of expan-
sion, because an equilibrium has been established between the
pressure of the expiratory muscles and the elasticity of the intra-
pulmonary gases which the closed glottis prevents from escaping,
the original density of these gases should be important. If they
are rarefied, the state of equilibrium will occur only with a
stronger contraction, or a smaller expansion of the thorax, and this
situation may be unfavorable to the phenomena of maximum ef-
fort,. But the effect, in any case, should not be of great impor-
tance.
Musschenbroeck had given a very ingenious explanation of the
death of animals in a vacuum. He had found their lungs "small,
flabby, solid (page 198), specifically heavier than water," and he
had considered that the death is the result of the stoppage of the
circulation which this collapse should produce; the same fact was
noted by the Dutch physiologists (page 202) , who interpreted it
a little differently. But these explanations cannot, however, be
applied to disturbances and death in an air which is much rare-
fied but still far from a perfect vacuum. Cigna long ago com-
mented that respiration should continue under these conditions,
as long as "the air is dense enough to expand the lungs by its
pressure"; but for that, it is sufficient "that this pressure should
overcome the resistance offered by the contractile force of the
lungs, for there is no thoracic air to increase this resistance, and
this pressure hardly exceeds that of two inches of mercury" (page
207).
It could not be better stated, and Cigna was replying in ad-
vance, without knowing it, to those who would later give an im-
portant part in mountain sickness to the tendency of the lungs to
retract under a lessened density of the intra-pulmonary air. Their
force, that is, their elasticity, is equal to only a few centimeters
of mercury, as Cigna had said. Therefore only under a still lower
pressure could the lungs separate from the thorax wall, making
a vacuum in the pleura. The supposed effect is therefore abso-
lutely nil.
Pravaz fell into a similar error when he said that "in mountain
air, respiration is mechanically restrained in its extent by the lack
of elasticity in the atmosphere which presses the interior of the
lungs" (page 239). His opinion is subject to the same objections.
But at least it has some appearance of probability, whereas I can-
not understand what made A. Vogt say that "the diminished at-
mospheric pressure assists greatly in the expansion of the thoracic
cavity, and thereby facilitates respiration" (page 237) .
346 Historical
The learned physician of Lyons seems to me no better inspired
when he ascribes to the diminished pressure the venous conges-
tions, because "the return of the blood to the right cavities of the
heart will be less active." His comparison of the heart to "a pump
operating in a medium in which the air is greatly rarefied, and
which could bring up water only from a much lessened depth"
(page 239) is not at all valid; no one believes now in the active,
sucking expansion of the heart.
In conclusion, we shall quote a more accurate idea of the same
author in regard to the recall of the venous blood by pulmonary
expansion. One might think that the force of this recall should
be decreased by the decrease in pressure. And yet, when we think
it over, we see that there is no proof there: the return* of the
blood of the large venous trunks towards the heart takes place
because of the difference between the tension of the outer air
and that of the air which enters the lungs and expands there, since,
as we proved long ago,5 in no animal can the opening of the glot-
tis suffice for the capacity of the respiratory pump. It would still
have to be demonstrated that this difference, the negative pressure
of the Germans, is less in rarefied air than in normal air, of which
we are by no means sure, and which is not even probable.
Excess of carbonic acid in the blood. We have reported with
all the discussion it deserves the strange theory of M. Gavarret
(page 275) , explaining mountain sickness by a real poisoning by
carbonic acid. According to the learned professor, the act of as-
cent would require such an increase of organic combustion that
the carbonic acid which is the product of it could not be expelled
quickly enough, in spite of the increase in the number of respira-
tory movements and heart beats. The result would be a storing
up which brings symptoms of poisoning; and also the improve-
ment which immediately follows rest, during which the excess of
gas is expelled.
This theory was accepted by M. Leroy de Mericourt, M. Aug.
Dumas, M. Scoutetten, M. Lortet (page 286), and many modern
authors.
I do not dwell upon the difference between the symptoms of
mountain sickness and those of poisoning by carbonic acid. But
it is quite evident that the theory of M. Gavarret is open to the
same objection which we used in disproving the theories involving
fatigue and the theory of M. Lortet. It is clear, in fact, that the
quantity of carbonic acid which must be produced in raising the
body 1000 meters, for example, is independent of the altitude; so
Summary and Discussion 347
that there must be an excess of gas stored up, and consequently
distress, just as much in ascending from Chamounix (1050 meters)
to the Pierre-Pointue (2040 meters) as in ascending from the
Grand-Plateau (3930 meters) to the summit of Mont Blanc (4810
meters) ; yet that has never been observed. Furthermore, even
at sea level, a iask which is sufficiently energetic and prolonged
should bring on the same result, and that is not the case. The
necessary element, altitude, is not considered at all in this ex-
planation.
As to the fact advanced, it in itself is far from proved. There
is no proof that the carbonic acid, the formation of which is in-
creased during the labor of ascent, can really be stored up in the
blood. According to M. Gavarret himself, when a man lifts him-
self vertically 2000 meters, he forms 65 liters of carbonic acid,
above the 22 liters which he produced per hour in his normal re-
quirements. It will take him at least six hours to cover these 2000
meters. (MM. Lortet and Marcet took 8 hours to go from Cha-
mounix (1050 meters) to the Grands-Mulets (3050 meters). We
must then add 65 liters to the 132 liters formed during this time;
in other words, the quantity of carbonic acid produced will have
been increased by one third. Now it is very probable that the pul-
monary excretion will have been sufficient to expel this small
gaseous excess; the arterial blood, the nutritive blood, the impair-
ing of which is so dangerous, is therefore probably not overladen
with toxic gas. On the other hand, we know, from the experi-
ments of M. CI. Bernard, that one can safely inject into the ve-
nous system of an animal enormous quantities of carbonic acid,
without producing symptoms, because of the rapidity and the en-
ergy of the pulmonary exhalation. And so nothing proves that
there is an excess of carbonic acid in the arterial blood; nothing
proves that this excess, if it exists, is capable in its actual propor-
tions of causing symptoms; at any rate, these symptoms should
appear at any altitude whatsover, and consequently have no con-
nection with mountain sickness.
Theory of de Saussure and Martins. De Saussure noted, as we
have reported (page 216), that, on the summit of Mont Blanc,
"since the air had hardly more than half of its usual density, com-
pensation had to be made for the lack of density by the frequency
of inspirations. . . . That," he said later, "is the cause of the fatigue
which one experiences at these great heights. For, while the
respiration is accelerating, so also is the circulation." The former
view, however, was incomplete, or, rather, incompletely expressed.
348 Historical
De Saussure gave one to believe, in fact, that the respiratory ac-
celeration could compensate lor the decreased density of the air.
Now he certainly knew that that was not the case, and that on the
summit of Mont Blanc neither the number nor the amplitude of
the respirations doubled the pulmonary ventilation.
This explanation was accepted by all the authors who followed
de Saussure. Halle and Nysten (page 217), Courtois (page 218),
Gondret (page 220), Clissold (page 223), von Humboldt (page
227) , Brachet (page 235) , Lepileur (page 236) , A. Vogt (page 237) ,
Pravaz (page 239), Marchal de Calvi (page 240), Meyer-Ahrens
(page 243), Lombard (page 244), Longet (page 250), etc., repro-
duced it in different forms. Some were satisfied with speaking, as
de Saussure had done, in a rather vague manner of the insufficient
quantity of air brought into the lungs at great heights; others, mak-
ing more definite statements, declare that, since less oxygen reaches
the lungs in a given time, less of it must be absorbed by the blood,
and hence the symptoms; some, like Longet, deny this conclusion,
affirming that "the person who dwells on the mountains ....
compensates by more frequent inspirations, so that . . . the same
quantity of oxygen can be absorbed in the same time" (page 250) .
M. Martins criticized this evident mistake; he declared that
there must be a lessened oxygenation of the blood resulting from
this insufficient pulmonary circulation, and hence "a physiofogical
cause of cold peculiar to high altitudes, and probably the principal
among all those causes which bring on the symptoms known by
the name of mountain sickness" (page 254) .
But we have revealed the fundamental objection which Pay-
erne (page 240) raised against the theory of de Saussure. In his
opinion, there is quite enough oxygen in the air, even on the sum-
mits of the highest mountains attained, to satisfy the needs of
respiration and to meet the requirements of the combustions in-
creased by the work of ascent.
Lombard alone (page 251) seems to be affected by the cal-
culations of Payerne; he makes no objection to them, and admits
that "even at altitudes of 7000 meters, the atmosphere can furnish
man with a quantity of oxygen sufficient to maintain respiration"
(page 252). Nevertheless he drew the conclusion "that an in-
sufficiently oxygenated blood reaches the different organs . . . This
is the cause of a considerable part of the disturbances which occur
in innervation and motility" (page 252) .
In another part of this book, I shall discuss thoroughly the ob-
jection of Payerne, and I shall show how much truth it contains.
Summary and Discussion 349
But here I shall merely show that no one replied to it, and that
consequently the theory of de Saussure, with the chemico-phys-
iological commentaries with which it has been enriched, is now
considerably damaged by it. If, even at 7000 meters, and without
taking into account the respiratory acceleration, much more oxy-
gen enters the lungs that is required by the organic combustions,
why should not the blood take what it needs and what it can find
there?
And first, as a fact and not as a theory, is the blood really "less
thoroughly oxygenated," as Brachet said? It is interesting to note
that Hamel was the only one to suggest performing an experiment
to "extract, on the summit of Mont Blanc, the blood of some ani-
mal, and to see by its color whether it had been sufficiently de-
carbonized in the lungs" (page 223). Yet we must confess that
the purple tinge of the lips and the conjunctiva furnished some basis
for the statements of those who maintained that oxygenation
was incomplete: when one of Clark's guides had the nosebleed,
"his blood seemed darker than usual" (page 91).
Theory of M. Jourdanet. Some authors had glimpsed, as an
explanation of this insufficiency of oxygenation, a cause other than
the one which we have just been discussing. It was not merely
the insufficient quantity of oxygen circulating in the lungs in a
given time which they blamed; but, to borrow the actual words of
Pravaz, "the lack of pressure which makes the solution of this gas
in the blood less abundant" (page 239). This idea was clearly
formulated only by Pravaz, in the passage which I have just
quoted: no one adopted it afterwards. M, Gavarret opposed it
energetically; the learned professor of the Faculte de Medecine
of Paris declared "that the absorption of oxygen by the venous
blood is not a purely physical fact, but that chemical forces play
an important part in this fixation" (page 250). Moreover, if it
were so, what would become of the people living at the dairy farm
of Antisana, where the barometer stands at 47 centimeters, who
would absorb "a weight of oxygen two thirds less than that con-
sumed at sea level"? And Longet said a little later: "If the law
of solutions applied, we should reach this conclusion, that the blood
of those living in regions where the atmospheric pressure is hardly
0.380 meters would contain only half as much oxygen as the blood
of those who live at sea level .... But, of course, the preceding
law does not have an application here" (page 250) .
But the point here was to find out what did happen to these
dwellers in lofty places, and the reasoning of the learned profes-
sors was a real vicious circle. Fortunately for them, the notable
350 Historical
experiments of M. Fernet (page 249) , carried out meanwhile, ap-
peared to justify them completely, seeming to show that the vol-
umes of oxygen absorbed by the blood are almost independent of
the barometric pressure.
Everyone yielded then to these conclusions supported by ex-
periments which give no opening for any objection of a purely
physico-chemical type.
M. Jourdanet alone (page 258) did not declare himself con-
vinced. He remarked shrewdly that no matter how great was the
affinity of the corpuscles for oxygen in the respiratory act, there
was no doubt that in an air with low oxygen content, the solu-
bility of this gas in the blood would be less. It cannot be other
wise in rarefied air, and the blood there must take up a lessened,
and possibly an insufficient, quantity of oxygen. Join to that the
decrease due to the cause of which de Saussure had spoken and
to which M. Jourdanet attributes considerable importance, and you
will become convinced, he thought, that on the mountains the
blood has a lower oxygen content than at sea level; and this de-
crease in oxygen, although the number of blood corpuscles remains
the same, produces the same dangerous effects as a decrease in
the number of these corpuscles. Anoxemia is the pathological
counterpart of anemia; thence comes this notable statement: "An
ascent above 3000 meters is equivalent to a barometric disoxyge-
nation of the blood, as a bleeding is a corpuscular disoxygenation"
(page 261). When the symptoms are carried to the extreme, as
happens on lofty mountains, the violent symptoms which we have
described are the result of the irrigation of the organs by a blood
containing too little oxygen, incapable of. stimulating and nourish-
ing them. At lower altitudes, as on the Mexican plateau, the dif-
ference in the oxygen content is not great enough to bring on dis-
turbances serious enough to attract attention, in the usual condi-
tions of life. But if some illness is contracted, it will immediately
take on a character so peculiar that an experienced physician will
at once recognize in his patient a real anemic. This is the general
thesis which M. Jourdanet has ardently sustained since 1861; he
has supported it in the successive works, which we have already
reviewed, with an astonishing number of personal observations
and quotations in agreement with them.
To be sure, more or less definite statements had been made
before his time, as we have seen, about insufficient absorption of
oxygen, and even about blood incompletely oxygenated; but no
one had connected the two causes which may produce a low oxy-
gen content in the blood, or measured their importance, or shown
Summary and Discussion 3d:.
their prevalence; no one seemed even to have supposed that they
could act at moderate altitudes, where no violent symptom attracts
the attention of the traveller or the physician; no one had fol-
lowed their consequences and shown their dangerous effect under
pathological conditions; and finally, no one had tried to discover
what part they play in the hygiene of peoples inhabiting lofty
places, what effect they produce upon their character, their cus-
toms, and their destiny.
If it is true to say that the discovery belongs, not to the one who
has found the truth, as if by chance, and who has carelessly ex-
pressed it, but to him who, perceiving it in his turn, has felt its
whole importance, has collected proofs to support it, has defended
it against bitter attacks, even when they came from eminent au-
thorities; who, in a word, has made a theory out of an isolated idea,
it is to M. Jourdanet and not to de Saussure, Martins, Brachet, or
Pravaz that we shall give the credit for having found the true ex-
planation of the symptoms of decompression, as he already has
the credit for having so clearly denned and described them by
the name of anoxemia.
However, we must note here again that the basis of the theory
rested only on reasoning and deductions, very well connected, to
be sure, but not sufficient to establish complete proof to minds ac-
customed to the precision of scientific methods. It was necessary
to make experimental proof of anoxemia and of its effect upon the
production of the symptoms which appear in rarefied air. I had
already said in 1869: "I cannot repeat too often that these are
reasonings, likelihoods, probabilities at most. When shall we have
the experimentation which will bring conviction? Who will do
for the study of respiration, under decreased or increased pres-
sure, what the King of Bavaria did when he furnished Pettenkofer
with all the apparatus necessary for the study of the products of
normal respiration?" G
This appeal was heard. M. Jourdanet himself permitted me
to subject to experimental test both his own theory and all those
which deserved to be examined thus. The account of the experi-
ments which I made with the help of the apparatuses which I had
secured, thanks to him, will form the second part of this work.
And now in completing this review of the opinions suggested
to explain mountain sickness, I have only to remind the reader in
summary that many of them could not withstand the critical ex-
amination to which we subjected them; that others, whose ac-
curacy is not very likely, are awaiting, for final judgment, experi-
352 Historical
mental control; that still others, and among them the one which
seems to us to have the firmest foundation, that of anoxemia, can
bring conviction only by the aid of the supreme judge: experi-
mentation.
1 Comptes rendus de V Academic des sciences, vol. XX, p. 1502; 1845.
-Journey from Quito to Cayambe.—Joumel roy. geogr. Soc, vol. XXXI, p. 184-190, 1861.
3 Etude de I'Jnfluence dc I'altitude sur la frequence des battements du coeur. Bulletin de
la Societe vaudoise des sciences naturelles, vol. XIII, p. 391-399, 1873.
1 De I'influence de I' effort sur les organes renfermes dans la cavite thoracique. — 'Paris.
1820. *
5 P. Bert, Lecons sur la physiologic de la respiration. Paris, 1870, p. 381-389.
aLecons, etc., p. 129.
I
Title II
INCREASED PRESSURE
Nature offers no conditions where man and air-breathing living
beings are subjected to the effect of a pressure greater than that
exerted by the atmosphere at sea level.1 Only aquatic animals and
plants endure pressures which may, in the depths of the ocean,
be reckoned in hundreds of atmospheres.
The quest for minerals, especially coal, has compelled many
laborers to live at depths where the normal pressure of 760 mm.
is increased by several centimeters of mercury. But the effect of
this slight modification has never attracted the attention of
observers, lost as it is, admitting that it is of some importance, in
thd host of peculiar and unfavorable conditions under which
miners live (dampness, darkness, confinement, deleterious gases,
dusts, etc.)
But since the sixteenth century, the progress of industry has
caused men to work under pressures beyond four atmospheres.
Diving bells, diving suits, and the caissons with compressed air
invented by M. Triger have placed thousands of workmen in this
modified medium. Serious symptoms have appeared, the number
of which has terrified engineers and physicians.
However, the latter, struck by the strange and often favorable
changes which a stay in compressed air causes in certain patho-
logical conditions, had the idea of regulating the use of this new
therapeutic agent. Apparatuses have been installed, which have
been of service in making interesting physiological observations
and useful medical applications.
In the following chapters, I shall report the data observed
under the circumstances which I have just mentioned. A consider-
able difference will be noted among them, if they are considered
as a whole. Divers and laborers in caissons are subjected to
353
354 Historical
pressures which are sometimes enormous; attention has been at-
tracted only to symptoms appearing when these pressures were
very high; and finally, these symptoms are, as we shall see, the
result, not of the compression itself, but of sudden decompression.
In medical apparatuses, on the contrary, the pressure used has
always been low, less than double normal pressure; the physi-
ological observations have been made on the phenomena produced
by the compressed air itself, and no symptom could be charged
to the decompression, which was always very gradual.
I therefore had to divide into two chapters the report of such
different data. A third is devoted to the account of the attempts
made by various authors to explain the physiological changes and
the more or less dangerous symptoms which attack the workmen.
Finally, in the last chapter, I have summarized and discussed the
data observed and the theories suggested, with the purpose of
explaining them.
1 The small, almost uninhabited regions, where the ground is below sea-leve
course, be excepted; the most important, certainly, is the valley of the Dead Sea.
Chapter I
HIGH PRESSURE
1. Diving bells.
At the beginning of the sixteenth century Sturmius invented
the diving bell, which was to render such great services. It was
simply a bell heavily weighted, which, full of air, was allowed
to sink vertically in the water until it touched the bottom. The
water penetrated the apparatus to a height which increased with
the depth of the immersion: at ten meters, there was under the
bell, in volume, half air and half water; at twenty meters, two-
thirds water and one third air, etc.; the workmen, who were
ensconced up to that point on seats like shelves, got down from
them to work under the worst conditions.
The inventor considered the harmful effect which the air com-
pressed by the descent might exert upon them; to prevent it, says
Panthot,1 he advised that air should be taken along in bottles
which would afterwards be broken under the bell.
This procedure, which could not alter at all the tension of the
air, was improved upon by Halley, with a purpose in greater har-
mony with the laws of physics. The English physician planned
to drive out the water which encroached upon the workman and
to renew the air which had been made foul by his respiration; he
'did so by letting down under the bell small barrels full of air,
which the diver received and opened at will; the warm and foul
air escaped from the top of the bell by means of a valve. Halley
even found the means of permitting a diver to leave the bell,
keeping in communication with the compressed air contained in it
by mean of a tube and a helmet covering the head. (Brize-Fradin,
2nd. S., pi. I.) . This was the first idea of the diving suit.
Spalding made improvements of a purely mechanical type in
Halley 's apparatus; these improvements did not prevent him from
meeting death in his own apparatus in 1785.
355
356 Historical
Brize-Fradin, from whose work 3 I have borrowed most of the
preceding information, summarizes in the following words the
disadvantages of the diving bell:
1. Keen and unendurable pain in the ear, due to the compression
of the tympanic membrane;
2. Deterioration of the air by the breathing of the workmen, with
asphyxia as the result;
3. Most physicists have found a third disadvantage; they believe
that the elasticity of the air, acting in all directions and at all depths,
compresses the blood vessels, and the arteries, and causes hemorrhages.
We may oppose to this statement unvarying data and direct
experiments; let us listen to M. Halley:
"I myself was one of the five persons who dived to the depth of
18 meters, without being inconvenienced by it; we remained for an
hour and a half; I could even have staid there longer, for there was
nothing to prevent it."
This testimony of M. Halley could be seconded by that of all the
divers. The pressure of the air under water, at a depth of 18 meters,
does not cause blood-spitting; if one dived deeper, of course, he would
find the limit where the compressed air could not be breathed. (P. 171)
And yet, adds Brize-Fradin:
Noting the equal value of the water pressure and the compression
of the air, it seems that the diver placed under the bell at a depth of
18 meters should be in a state of general collapse. (P. 173)
The Court Councilor of the Emperor of Russia, whose fatal
ascent of Mont Blanc we have already reported, Dr. Hamel,4
descended in a diving bell installed by Rennie in the port of
Howth, near Dublin; the depth of the water was about 30 feet.
He felt no other inconvenience than violent pains in his ears, "as
if some one were forcibly inserting a stick," which he checked
by swallowing his saliva. From that the idea came to Hamel "that
the divers' bell might serve as a remedy in cases of deafness
resulting from the obstruction of the Eustachian tube."
In regard to the rest he merely says:
I expected to experience some painful effect upon respiration,
resulting from the pressure of the air increased by the weight of
almost a whole atmosphere; and yet I did not feel the least incon-
venience in this respect.
The same year, Dr. Colladon B descended in the same bell and
to the same depth. He is a little more explicit:
We descended so silently that we did not perceive any movement
of the bell; but as soon as it was immersed in the water, we felt in
our ears and on our foreheads a sensation of pressure which kept
Diving Bells and Suits 357
increasing for several minutes. However, I did not experience any
pains in the ears; but my companion was in such pain that we had to
stop the descent for a few minutes. To remedy this distress, the
workmen advised us to swallow our saliva, after closing the nostrils
and the mouth tightly, and to hold our breath for a few instants, so
that, by this exercise, the inner air might act upon the Eustachian
tube. My companion got little relief from this procedure. When we
began to move again, he was in great pain, he was pale, his lips had
lost their color, one would have thought him nauseated. His prostra-
tion was due, no doubt, to the violence of the pain, added to a fear
which he could not overcome. This experience produced the opposite
effect upon me: I was in a state of excitement, as if I had drunk some
alcoholic liquor, I had no pain, I merely experienced a strong pressure
around my head, as if an iron ring had been fastened tightly about
it. While I was talking with the workmen, I had some difficulty in
hearing them; this difficulty in hearing became so great that for three
or four minutes I did not hear them speaking; I did not even hear
myself, although I was talking as loud as I could, and soon the noise
caused by the violence of the current against the walls of the bell no
longer reached my ear. (P. 6) ....
At last we reached the bottom of the sea, where every disagree-
able sensation ceased almost entirely ....
We breathed very easily during our whole visit under water ....
Our pulse rate showed no change .....
As we rose again, our sensations were very different from those
we had experienced as we descended; it seemed to us as if our heads
were becoming much larger; that all our bones were on the point of
separating. This discomfort did not last long. (P. 8.)
To these almost negative observations, Colladon adds two facts
which are most interesting and which were the point of departure
of important therapeutic applications:
None of the workmen become deaf; it would rather seem that in
certain cases, the effect of the bell on the ears might serve as a remedy
for deafness. One of the workmen, who had habitually breathed with
great difficulty, was completely cured shortly after undertaking work
in the bell. (P. 14.)
The diving bell today is completely abandoned. It has been
replaced by caissons filled with compressed air by the Triger
method.
Interesting attempts have been made repeatedly to invent
submarine boats in which men would live either in compressed
air or in air at normal pressure. These attempts began in the
seventeenth century; Father Mersenne, the friend of Descartes,
did not scorn to apply himself to the subject; more recently R.
Fulton in the port of Brest made attempts which perhaps should
have been encouraged; then came Payerne, whpse submarine
hydrostat operated with some success. In our own time, M. Villeroi,
358 Historical
then Rear-Admiral Bourgeois invented cigar-boats which might be
used in case of war. But since no observation of a physiological
nature has been made with the help of these contrivances, and
since I have no desire to write a history, no matter how short, of
the industrial applications of compressed air, I now come without
other transition to the numerous data relating to the digging of
mine shafts and to the sinking of bridge piers by the Triger
method.
2. Apparatuses Constructed by the Triger Method.
It is, in fact, to M. Triger, a French engineer, that we owe the
valuable invention of the use of air compressed to high pressures
for boring mine shafts and sinking bridge piers. It was a question
of working in the grant of Haye-Longue (Maine-et-Loire) coal-
bearing strata covered with alluvial deposits over which flowed
the waters of the Loire. It was impossible to drain off the water
which seeped through and prevented them from extending the
galleries: M. Triger conceived the simple but brilliant idea of
driving it back and holding it by pumping compressed air in
through the upper part of the shaft; protected by the drainage
thus secured, workmen could stop the leaks by vaults of masonry.
M. Trouessart, whose report on this wonderful discovery we
shall quote later, comments that Denis Papin had already had an
idea of this sort, in 1691, and he quotes the following passage,
which is indeed very noteworthy:
Fresh air could be injected constantly into the diving bell by-
means of a strong leather bellows furnished with valves, by a tube
passing under the bell and opening into its upper part. And so, since
the bell would always remain empty and rest entirely on the ground,
the bottom in this place would be almost dry and one could work
there just as if he were out of the water, and I have no doubt that
it would save much expense when construction must be carried on
under water. Moreover, in case the leather bellows were not strong
enough to compress the air as much as would be necessary at great
depths, one could always meet this difficulty by using pumps to com-
press the air.
But from this idea to the complete invention of M. Triger is a
long way; in 1839, he solved the problem from a practical stand-
point, and listed the numerous applications which would later be
made of it.
The complete explanation of this invention is in a Memoir 8
presented to the Academy of Sciences in 1841.
We naturally omit all details of the construction of the appara-
Diving Bells and Suits 359
tuses and come to the mention of physiological phenomena, not
much considered, as we shall see, by the celebrated engineer.
An interesting fact appears at once; M. Triger wished to try
upon himself the effect of compressed air. Now:
At the moment when the manometer had hardly risen to the
height of 40 inches (total pressure), there was a report, and we were
struck with icy cold and plunged into the most complete darkness,
because of the instantaneous formation of a thick mist: a windowpane
of the apparatus had burst.
This explosion had no other result that to cause us a great
surprise.
M. Triger next mentions, ascribing them quite accurately to
their cause, the pains in the ears that accompany compression and
decompression. Then he adds, and this is all his Memoir contains
on the subject which interests us:
At the pressure of three atmospheres, it is not possible to whistle
in compressed air: but the power is lost only when one reaches this
pressure.
In compressed air, everyone talks through his nose, and this
becomes increasingly noticeable with increase in pressure.
The workmen have noticed that while they were climbing the
ladders, they were less out of breath in compressed air than in free air.
I shall end with a rather interesting observation, which I was in
a position to note personally: namely, that a miner, named Floe, who
had been deaf since the siege of Antwerp, invariably heard more
distinctly in compressed air than any of his comrades. (P. 892.)
Professor Trouessart,7 commissioned by the Industrial Society
of Angers to investigate the practical results of the apparatus of
M. Triger, gave an account of his researches in an interesting
Memoir.
There is very little mention of physiology in it; however, we
do find in it a few observations which deserve to be reported here,
particularly because they were the first made on man at pressures
of 3 atmospheres above the normal atmosphere:
It is with a certain apprehension, we admit, that one goes down
for the first time into the apparatus to be subjected to a pressure
of three atmospheres there. These 32,000 kilograms above the former
pressure which you will have to endure are enough to terrify the
stoutest shoulders.
First comes the description of the pains in the ears, which are
thoroughly studied and explained:
A phenomenon which is more difficult to understand is that deaf
persons not only hear better in compressed air than in free air, but
that they hear better than persons whose ears are normal ....
360 Historical
One of the strangest results is that one suddenly loses the power
of whistling under the pressure of 2% to 3 atmospheres.
The functions of nutrition, respiration and circulation do not seem
perceptibly altered in compressed air. At the time of our first visit,
we thought that we found an increase in the pulse rate of every one
subjected to the experiment; but on our second visit, the result of a
more accurate observation, made by a member with much experience
in taking the pulse, was completely negative ....
The respiration is neither slower nor faster. It seems that it is not
more active and that the animal heat is not increased. The blood too
gushes out under normal conditions. In a word, the most surprising
thing is that there are very few changes in the vital functions. The
workmen assert that they climb the ladder more easily and are less
out of breath when they reach the top. This cannot result from the
rather slight loss in their weight. Is it possible that they can hold
their breath longer because of the greater density of the gas inhaled
at each respiration? On the other hand, they maintain that they
become much more tired when working in compressed air than in
open air. We think that this is the result of the very great humidity
of the atmosphere of the shafts, which hampers the insensible perspi-
ration and promotes the more rapid secretion of sweat in those who
have to exert their muscular powers in such a medium. Perhaps this
humidity would also explain the somewhat severe pains in the ar-
ticulations experienced by some workmen a few hours after leaving the
shaft ....
We may conclude that there is no serious danger in staying several
consecutive hours for several successive days in air compressed to 3
atmospheres.
Our author says nothing of the duration of the decompression;
he seems, moreover, to pay more attention to "the passing from a
low to a high pressure": he only says that they opened the cock
gradually.
In a second communication to the Academy of Sciences, M.
Triger s repeats his former observations. He adds to them the
following data:
Everyone talks through his nose and loses the power to whistle
at 3 atmospheres. To ascertain the effect of compressed air on a
stringed instrument, I had a violin taken down into the shaft and it
was found that at the above pressure the sound lost at least half
of its intensity.
Then comes the first suggestion of the rather serious symptoms
of decompression:
I should say here that two workmen, after passing 7 consecutive
hours in compressed air, experienced rather keen pains in the arti-
culations, half an hour after leaving the shaft. The first complained
of a very sharp pain in his left arm, and the second experienced a
similar pain in his knees and left shoulder; rubbing with spirits of
Diving Bells and Suits 361
wine soon relieved this pain in both men; they kept on working the
following days.
In 1846, M. de la Gournerie,9 getting his idea, he said, from an
apparatus suggested in 1778 and approved by the Academy of
Sciences in 1779, used for the extraction of rocks in the channel
of the port of Croisic a boat with a metal chamber open at the
bottom, from which the water was expelled by compressed air.
He submerged it only 3 or 4 meters; it is not surprising then
that
The workmen never found that the air pressure inconvenienced
them. It merely gave them a slight discomfort in the ears for a few
seconds.
The pulse rate is not noticeably increased. (P. 308.)
In the mines of Douchy (Nord) the method used by M. Triger
on the banks of the Loire was first imitated. The difficulties were
greater, because here it was not a matter of penetrating permeable
sands with a sheet-iron tube 1.50 meters in diameter, but of
digging a shaft 3 meters in diameter through limestone.
We shall shortly quote the important Memoir which the physi-
cians Pol and Watelle devoted to the study of the symptoms which
attacked numerous workmen in this undertaking. The first ac-
count of them was given by a report of the engineer Blavier,10
sent to examine this new invention.
He first mentions the pains in the ears and the inability to
whistle. A certain effort must be made in speaking:
It seemed to us also that in the diatonic scale the voice lost a tone
or a tone and a half in the upper notes without gaining in the lower
ones.
He found no difference in the pulse rate before entering the
apparatus and while within it:
If the effects of compressed air upon the animal organism do not
appear during the whole time that one is subjected to it, at least
during one shift of workmen, the same thing is not quite true if we
try to consider subsequent effects .... Most of the workmen, although
selected from the most robust and healthy, have frequently felt
heaviness in the head or pains in the legs a few hours after leaving
the caisson. Only one of them experienced complete paralysis of
arms and legs for 12 hours. The superintendent of the mine assured
us that the effects felt almost always coincided with some excess
committed between shifts. (P. 361.)
However, Blavier himself, after being subjected to the total
pressure of 2.6 to 3 atmospheres, was attacked by a fairly severe
symptom:
362' Historical
The day after our visit of December 5, keen pains appeared in
the left side, and we felt a rather severe painful discomfort for several
days afterwards. Since a chill or some other cause not connected with
the compressed air might have been acting, after we were quite free
from these pains, December 28, we were anxious to try the experiment
again, and when we left the shaft, we took the greatest precautions to
protect ourself from any chill. In spite of these precautions, the
next day, very noticeably at the same hour, that is, 20 hours after our
exit from the medium of compressed air, we felt in the right side pains
just like the former ones, which kept us numb for four or five days.
(P. 362.)
We now come to the important Memoir, the first written by
physicians about these symptoms, in which MM. Pol and Watelle 1X
recount the effects of compressed air upon the miners during the
excavating at Avaleresse-la-Naville, at Lourches, in the grant of
Douchy (Nord).
The authors took care to warn the reader that since their notes
were made without any intention of publication, they made their
observations without plan, without program, and consequently
without system. But they thought, and with good reason, that
their work would nevertheless present some interest and some
utility.
During the exploitation, the total pressure rose to 4V4 atmos-
pheres. The compression was made in a quarter of an hour, the
decompression in a half -hour; 64 workmen took part in the work;
they usually stayed four hours consecutively in the apparatus,
twice a day.
The authors described separately the physiological effects
which they observed in themselves and the pathological effects
experienced by the workmen:
1. Physiological effects: Pains in the tympanic membranes;
slowing of the respiration and particularly a decrease in the
amplitude of the thoracic expansion, which became hardly per-
ceptible; slowing of the pulse, (from 70 to 55) ; increase of urinary
secretion.
The authors also mention a "muscular sensation of a resistance
to be overcome, as if the unusual density of the ambient atmos-
phere hindered movement; the inability to whistle, experienced
above 3 atmospheres, is also attributed to an unexpected resistance,
experienced by the muscles of the tongue in compressed air.
On the return and during the decompression, they experienced
a keen sensation of cold, a kind of panting; the pulse rose to 85.
Pathological effects. Taking the observations as a whole, we
Diving Bells and Suits 363
see that out of 64 men, 47 withstood the work fairly well; 25 had
to be discharged; 2 died. Taking them in detail, we see that 14
felt slight symptoms, 16 more or less severe symptoms, sometimes
even threatening life; 2 died.
On the other hand, 2 benefited by a certain improvement. One
(First category, obs. I) was asthmatic, and breathed better in the
shaft; the other (Third category, obs. 3) chloro-anemic, having had
frequent blood-spitting, found that his oppression /disappeared
and his mucous membranes became redder:
We see dawning, (MM. Pol and Watelle said in this connection)
without concealing the difficulties of application, a new resource of
palliative therapeutics in the treatment of most dyspneas. •
The universal rule without exceptions was that the symptoms
appeared at the time of decompression:
The danger does not lie in entering a shaft containing compressed
air; nor in remaining there a longer or shorter time; decompression
alone is dangerous: pay only when leaving.
Let us see now what these more or less serious symptoms are.
They are, first, pains in the eardrum, more or less severe and
lasting, and M. Pol states that they can be checked much more
quickly by blowing one's nose than by going through the motion
of swallowing.
As for the other symptoms, as MM. Pol and Watelle had the
good sense to give the complete observations, I think I cannot do
better than to summarize each in a few words, following the order
in which they presented them:
First Category. Workmen on the Job from the Beginning.
Observations. I. Asthmatic, breathes better in the shaft. On
decompression, violent oppression with exaggerated circulatory re-
action. Discharged.
II. Went up to 4V2 atmospheres. Respiration hampered, decrease
of appetite, indigestion, pains in the limbs. Stools dark. Lost much
weight.
III. Same effects.
IV. Same.
V. Did well up to 3 atmospheres. After that, dizziness, muscular
pains, cramps or general numbness, vomiting of dark matter. All
this on the return to open air.
One day, an hour after leaving the shaft, having eaten, he com-
plained of distress; when placed in bed, he lost consciousness. Pulse
full and rapid, face congested, respiration short and stertorous; obscure
sound everywhere, bronchial murmur, mucous rale; muscular reso-
lution. Bled, purged, plastered. After four hours, return to conscious-
ness. In three days, cured. Discharged.
364 Historical
VI. Taken to 4V4 atmospheres without accident. One evening,
after going to bed apparently well, at 11 o'clock seized by muscular
pains accompanied by contractions like tetanus spasms.
Skin cold, pulse small and slow, urine abundant and clear. Respi-
ration uneasy; same results of auscultation as V.
Baths at 32° so aggravated the pains that the patient could not
remain in them. Friction, strong sudation, quiet. Recovered next day,
back at work.
VII. At a pressure of 3.3; cerebral disturbances, like intoxication
with coma, hebetude, stuttering. Respiration accelerated, pulse rapid.
Pupils dilated.
Two similar attacks, cured one in nine days, the other in fifteen.
Continuance of double vision and vertigo, with deafness oh one side.
Discharged.
VIII. Presented an excessive form of two common phenomena:
1. suppression of the functions of the skin and increase of the urinary
secretion during the compression: 2. increased rapidity of the heart
beats after decompression; his pulse rate rose from 58 to 130.
IX to XVII. Nothing important to be noted.
XVIII. Healthy and vigorous. Experienced repeatedly keen pains
in the limbs and chest. Respiratory disturbances increasing with the
pressure, as well as the muscular pains which were very acute.
Was discharged. During the last days went down into the shaft
without permission. Worked there without complaining; went out
with his companions, washed himself like them, immediately fell
unconscious and died in a quarter of an hour. Autopsy shows only
obstruction of the lungs, congestion of the liver, the spleen and the
kidneys; nothing in the brain except gritty congestion.
XIX. Violent oppression with dullness on percussion and bronch-
ophony; rapid pulse, cold skin, continual cough; clonic contractions
of the limbs; more sensitive after five hours of treatment.
Then, at another time, to these symptoms are added: dilation of
the pupil, relaxing of the limbs, subdilerium, coma. Three bleedings in
rapid succession; blood bright red on leaving the vein; cured. Dis-
charged.
XX. Same symptoms as VII. Also, remained deaf on one side, with
vision much weakened. Discharged.
XXI. One day, sight affected and double, hearing gone; respiration
hampered, cough frequent, pulse hard and galloping. Blood red,
recovered.
XXIV and XXV. Nothing important.
XXVI. Usual thoracic and cerebral symptoms; recovered after
profuse sweatings. (P. 250 to 259.)
Special Category of men who worked only one day and without
preparation at 2.8 atmospheres.
Nine men left the shaft without making any complaint. But
shortly afterwards, eight experienced very severe muscular pains,
which disappeared during the night, except in one, in whom they
persisted several days.
Diving Bells and Suits 365
Second Category. Workmen who worked only above 2.9 atmos-
pheres.
I. No effect.
II. Only muscular pains in the left thigh, which yielded to cold
water.
III. IV. Nothing.
V. Moderate muscular pains, but persisting from one shift to the
next; recompression relieved them immediately.
VI. Nothing.
VII. 28 years old. Athletic. Pressure of 3.8 at the beginning. After
10 days, loss of consciousness, violent lockjaw. Rapid pulse.
Reddish bleeding eight hours afterwards, purging, blisters.
Two days after, consciousness suddenly returned: the patient
opened his eyes, seemed to awaken from a dream, said a few aston-
ished words.
Recovers, but remains extremely deaf.
Third Category. Workmen who began at 4.154 atmospheres.
I, II. Nothing.
III. Had previous hemoptysis. Improvement.
IV, V, VI. Nothing, except rather severe muscular pains.
VII. 40 years old. Very robust. Went down into the shaft only
once. On coming out (decompression in twenty minutes) died almost
immediately.
Autopsy held 36 hours after death: generalized subcutaneous
emphysema (existed before putrefaction began, the authors note) ;
nothing in the meninges, in the brain, or the cerebellum; congestion
of the lungs with generalized darkish tint (underlined by the authors) ;
blood fluid and dark in the heart; liver, spleen, and kidneys congested.
VIII. Nothing.
IX. Moderate muscular pains.
X. At his first trial, very severe muscular pains, persisting for
several days. Discharged.
XI. Same.
XII to XIX. Nothing, except insignificant muscular pains. How-
ever, they sustained the pressure of 4y4 atmospheres for three
months.
XX. At his first trial, too rapid decompression. A few minutes
after his leaving the lock-chamber, looked like a corpse: face pallid,
icy cold, eyes dull, pupils enormously dilated, respiration uneasy; on
listening to the heart, heard only a vague quivering; pulse impercep-
tible; perception gone; involuntary urination; dark vomit; complete
loss of muscular power.
Warm bath, blankets, friction. After a half-hour, the pulse begins
to be perceptible, the respiration is deeper, a little warmth appears
in the body; the patient stammers disconnected words. During the
night, hardly has warmth been reestablished when acute pains appear
in the muscles; keen pains in the head, blindness and deafness;
wretched pulse, 50.
366 Historical
Evident improvement two days afterwards; the patient sees
vaguely. Vision remains weak and pupils are abnormally dilated.
XXI. At his first trial, too rapid decompression. Severe muscular
pains persisting for six days.
XXII. At his first trial, too rapid decompression. Loss of con-
sciousness, resolution of limbs; respiration embarrassed, pulse full,
hard, 130.
Bleeding blood red, blistering; after four hours, consciousness
returns. During the night, cramps and muscular pains of terrible
violence.
Survives, but with great weakness of vision and extreme deafness.
(P. 265-275.)
I shall now quote the description of the complication whicch
attacked M. Pol himself, because it contains the account of a very
strange symptom, upon the importance of which we shall dwell
later. The pressure undergone had been 3.48 atmospheres:
At 11 o'clock, he reached his lodging; he felt keen pains in his
left arm and shoulder; the walls of the thorax were also painful. It
seemed to him that emphysema existed in these regions .... About
midnight, he had a few chills, followed by vomiting. He took a cup
of tea and went to sleep; soon abundant sweat broke out. The next
day, he was in his usual condition. (P. 250.)
In summary, the symptoms noted, at the time of decompression,
are as follows:
Respiratory difficulties, which may go as far as anxiety;
Acceleration and hardness of the pulse;
Muscular pains which are often very severe: "none of the
effects of decompression appeared so general; sole symptom in
many cases, it is the initial symptom in almost all .... It is the
first and the largest link in a chain which includes successively,
by ascending order of severity and descending order of frequency,
non-permanent or clonic spasm, resolution, and finally sideration"
(P. 227) ;
Cerebral symptoms, dullness of intellect, loss of sensitivity and
consciousness, coma. Deafness, blindness, very often permanent;
Finally, sudden death.
The reading of the observations abstracted above shows what
a variety of form and intensity is presented by the symptoms, even
for the same pressures, in different individuals, and sometimes in
the same individual.
MM. Pol and Watelle noted that young men from 18 to 26
resisted much better than mature men; out of the 25 who were
discharged, 19 were more than 40 years old, and 5 were more than
30; the other was 28 years old.
Diving Bells and Suits 367
These symptoms are attributed by the physicians of Douchy
exclusively to pulmonary, hepatic, renal, or cerebral congestions.
In the special chapter devoted to the enumeration of theoretical
explanations, we shall see what theories of these pathological
phenomena were given by MM. Pol and Watelle.
I have wished to review at length their important Memoir, the
first study of high pressures to appear, not only because of the
numerous interesting observations reported in it, but also because
truths of great importance are clearly revealed by it:
1. "Compression, up to 4%, atmospheres, is not dangerous in
itself; it is endured very well and infinitely better than a rare-
faction which is proportionately much less." Only the return to
normal pressure is dangerous; its danger is proportional both to
the amount of the compression and the speed of the decom-
pression: the decompression must therefore be very gradual;
2. In compressed air, the venous blood becomes bright red. This
effect lasts a short time after return to normal pressure;
3. We are "justified in hoping" that a sure and prompt means
of relief would be to recompress immediately, then decompress
very carefully;
4. Chlorotic or anemic persons and those who have respiratory
difficulty will be benefited by a stay in air compressed to a variable
degree.
During the work at Douchy, an explosion occurred at a time
when the total pressure was 3.20 atmospheres. It was the subject
of a report by M. Comte,12 chief engineer of the mines. Eight men
were in the apparatus at the time; four were crushed to death;
two others, after beginning to climb the ladder to leave the cylin-
der, let go of it, without anyone ever being able to find out why or
how; a seventh workman felt no ill effects; the eighth, who was
overtaken by the water, also managed to escape. In regard to him,
M. Comte suggests a strange and interesting hypothesis, interesting
because it shows how easily the best minds go astray in these
questions:
Perhaps he found some help in rising above the water .... in
the specific lightness given him by the compressed air with which
certain parts of his body were still more or less filled. (P. 130.)
The new method quickly became general. Other shafts were
sunk, and data similar to those reported by MM. Pol and Watelle
were observed.
That happened, for instance, according to the report of Bouhy 13
in the mine of Strepy-Bracquegnies (Belgium) :
368 Historical
At Strepy-Bracquegnies, all the laborers, except one, who worked
in air compressed to 3.70 atmospheres, and from 4 to 5 hours conse-
utively, were attacked, after leaving the apparatus, by more or less
acute pains .... These pains, the seat of which was chiefly in the
articulations, such as the knees, the shoulders, and the joints of the
arms, appeared in certain persons so severely that they sometimes
went more than forty-eight hours without being able to sleep ....
It was noted that some laborers who had had rather severe attacks
and who had gone down to work were completely relieved of pain as
soon as they were in compressed air, but that the pains came on again
some time after they had left the apparatus.
Besides these effects, the author again mentions unpleasant sting-
ing over the whole surface of the body and especially on the ex-
tremities.
But compressed air is used chiefly on the foundation of bridge
piers, and it is under these conditions that hundreds of workmen
are exposed to its effects every year. It is therefore of interest
for us to explain briefly the mode of application of the Triger
method in this particular case.
Figure 6 will permit us to be very brief in our explanations; it
is a cross-section which we borrow from the memoir of Dr. Foley,
which will be reviewed later.
A cast-iron tube MM composed of concentric rings fastened
together by bolts m, and ending at the bottom of a widened cham-
ber or "crinoline," is let down upon the bed of the river in the
spot which the bridge pier is to occupy. It is topped at its upper
end by a room with 3 compartments; the one in the middle, F, is
in constant communication with the cast-iron tube; a blowing
machine, through a tube G, constantly pumps into it air which is
sufficiently compressed to drive all the water out of the cast-iron
cylinder, and escape constantly bubbling all around; the bottom
then becomes dry, as happens in a glass tube into which a child
blows after immersing it in water.
Under these conditions, the workman who is coming to work
opens the door of one of the lateral chambers, E, and closes it
behind him, and by a cock communicating with the central cham-
ber F, equalizes the pressure of the air about him with that of the
air in the cylinder. When this has been done, he easily opens the
inner door, hitherto held shut by the pressure, and goes down to
the bottom of the shaft by a ladder. There he works and fills with
the earth which he digs out buckets which are hauled up and
emptied outside. Does he wish to leave? He goes to the other
lateral chamber C in which the air has remained under pressure,
goes in, closes the door, and by a cock communicating with the
Diving Bells and Suits
369
exterior allows the excess of compressed air to escape. He can
then easily open the outer door and leave the apparatus.
Fig. 6— (borrowed from the thesis of M. Foley). Diagram representing
the construction of a bridge pier by caissons with compressed air.
As the work progresses and the excavation becomes deeper,
the cast-iron tube sinks of its own weight and that of the masonry
nn in which it is loaded; then more cast-iron rings are superposed
370 Historical
until the digging is finished; then there is nothing more to do but
fill the whole cylinder with masonry and the pier is finished.
It is by this method, which is so simple and yet which is much
more complicated in practice than the preceding description seems
to indicate, that a great many bridges have, been constructed since
1851.
The idea of this application of his system of drainage to the
foundation of bridge piers belongs to M. Triger 14 himself. But this
idea was not put into execution until 1851, by an English engineer
Hughes, in the construction of the Rochester bridge over the
Medway in the county of Kent.
An engineer of French descent, Brunei, constructed by this
system the bridge of Chepstow, over the Wye (1849-1851) and that
of Saltash (1854-1859) ; for the latter, the maximum depth reached
was 26.68 meters below high water. Only in connection with this
one did a fatal accident occur; a man died on leaving the cylinder
in which he had remained a very short time. I could not get
detailed information on these facts, however.
In 1856, M. Cezanne 15 was charged with the construction of a
bridge at Szegedin (Hungary), to permit the Austrian railroad
from the south-east to cross the Theiss, a tributary of the Danube.
He used the system of caissons with compressed air. The work
of excavating was "stopped at about 20 meters below high water,
so as not to expose the men to the pressure of 3 atmospheres,
beyond which work is very difficult." (P. 355)
A special section of the memoir of my regretted colleague is
devoted to the study of the physiological effects of compressed air:
There are three phases to be distinguished: the entrance, the stay,
and the exit.
When the cock admitting the air is opened, the ears are immediately
attacked by a violent buzzing accompanied by pains the intensity of
which varies with the individuals ....
The stay at the bottom of the caisson, in a pressure of three
atmospheres, may be prolonged for several hours without ill conse-
quences; the tone of the voice is somewhat impaired, and the
respiration hastened as if by rapid walking; if a cigarette is waved
about, it burns with a flame; candles burn rapidly, but with smoky
flame
The time of exit, though not very painful for the great majority
of individuals, is the most dangerous for the workmen .... Sometimes
there is an issue of blood from the nose and the throat; some persons
experience violent, but brief neuralgia; others have headaches and
toothaches for several days
Laborers who usually work in the caissons look ill; however, they
resist the ill effects very well. (P. 369.)
Diving Bells and Suits 371
December 12, 1859, there was an explosion at a bridge pier at
Bordeaux, and consequent instantaneous decompression; seven
of the laborers working there felt no ill effects. Two were killed,
but by purely mechanical causes.
M. P. Regnauld,1" who gave a report of the work, does not say
at what pressure this accident took place, but we conclude from
his Memoir that the caisson at that time had certainly been sunk
more than 12.90 meters, (p. 82)
In 1859, the bridge of Kaffre-Azzyat was built over the Nile:
the piers were excavated to a depth of 26 meters below the water.
Five Arabs died from the effects of the pressure: one in the cage,
as he was leaving, but before he had reached the open air; the
pressure was 36 English pounds per square inch.17 The others felt
ill in the caisson and died during the decompression; the pressure
then was more than 30 pounds. Blood issued from their mouths,
noses, and ears.
The Memoir of Babington and Cuthbert,1* from which I have
borrowed the preceding data, is particularly devoted to the medi-
cal study of symptoms observed during the laying of the founda-
tion of the bridge of Londonderry, in October, 1861.
The depth reached was 75 feet below water level:
The pressure sustained by the laborers was, at the maximum, 43
pounds per square inch, in all. They suffered from pains in the ears,
headaches, pains in the legs, nosebleeds, and general distress. These
symptoms increased greatly when the cocks were opened wide and
the change in pressure was therefore too rapid .... These symptoms
appeared first when the men entered the compressed air; but they
were much worse when the change was made from the caissons to the
open air: serious, even fatal, symptoms appeared then.
I am copying in abridged form the six observations of the au-
thors:
I. October 3, 1861. Man 28 years old, who had worked four hours
under a pressure of 23 pounds; when he came out, he fell unconscious.
Cold and livid; total insensibility, facial paralysis on the right side;
strabismus of the right eye; pupils almost motionless; pulse 150, small
and irregular; heart sounds hardly perceptible; respirations very
irregular, 24 to 44 per minute; inspiration abrupt, expiration pro-
longed.
Bleeding: blood dark, viscous and sticky .... Died 24 hours after
leaving the cylinder.
II. Case absolutely similar, occurred at the same time .... Died
also in 24 hours.
III. 23 years old. When we visited him, he was completely pros-
trated, but was conscious, and complained of pains in his legs and
thighs. Unable to walk, hands and feet cold and without sensation.
372 Historical
Was seated with his feet in the fire, so that several of his toes were
burned without his feeling the heat.
He had not become sick immediately, and as he had had pains
in his legs for days before, he had not called the doctor until several
hours after leaving the cylinder.
Two days afterwards he was cured except for his burns.
IV. Similar case. Hemoptysis. Cured.
V. 18 years old, October 3. Four hours under pressure; fell
unconscious while being decompressed .... In a semi-comatose state,
responded when stimulated and fell back into unconsciousness. The
symptoms of coma passed in 18 hours; he was then totally paralyzed
from the fourth rib. Retention of urine, loss of sensation, and other
symptoms of diseases of the cervical medullary region.
Died in the hospital 162 days afterwards; never regained sensi-
bility or movement.
VI. 30 years old. Identical symptoms; except that the paralysis
began only with the eighth dorsal vertebra. Lived 30 days.
Many other cases of slight paralysis, muscular pains, and other
nervous affections were also observed.
Unfortunately no autopsy could be made.
We shall see later the explanation which the two English physi-
cians gave of these data.
In 1859, a work of the greatest importance, the bed of the piers
of the bridge from Strassburg to Kehl, was carried out with the
use of compressed air. Two interesting Memoirs, one more 'par-
ticularly pathological, the other more physiological, reported to
us the sensations felt, the phenomena observed, and the symptoms
which appeared. The first in date is that of Dr. Francois; 19 we shall
discuss that one first.
The author begins by describing briefly the apparatuses used
in the construction of the bridge. One shift lasted four hours, and
there were eight hours of rest between shifts. The total pressure
rose to 3V2 atmospheres. According to the rules, the decompres-
sion should have taken from 6 to 8 minutes up to 2 atmospheres;
from 12 to 15 minutes up to 3 atmospheres; but the carelessness
of the laborers almost always prevented strict carrying out of this
rule.
Physiological effects. Easier, less frequent respiration; greater
expansion of the chest, "which explains itself;" circulation accel-
erated during the compression, then slowing at the time of the
return to open air; perceptible loss of weight, even in the work-
men who had no pains.
The author does not give much time to these data, and says
that they will be discussed in the work of M. Bucquoy which we
shall review presently.
Diving Bells and Suits 373
Pathological effects. These are first earaches and inflammations
of the ear, after which the hearing often remains much impaired.
Then pains in the muscles or the joints: there were 133 cases
of this sort. They disappeared after a few days. Sometimes there
was a rather evident local swelling, but without crepitation. In
one of the cases, the left breast of one of the workmen suddenly
swelled so as "to resemble the well-formed breast of a woman;"
this painful swelling quickly yielded to the application of cupping-
glasses with scarification. (P. 307.) In another case, the patient
was left unable to use his left leg.
M. Francois also mentions as frequent the itching of the skin,
fleas, as the workmen call it; it yields, he says, to washing with
cool water.
He explains, by congestions about the lungs, the heart, the liver,
and the spleen, some rather vague symptoms, in which suffocations,
palpitations, etc. are involved; one of the patients, who was, more-
over, subject to hemoptysis, died a few months afterwards.
Finally, the violent headache and the loss of consciousness are
attributed to a cerebral congestion; these congestions began only
after a quarter or a half an hour. In one of these cases, the work-
man, who left the caissons (3 atmospheres) without experiencing
anything but a very uncomfortable prickling over the whole body,
walked to the citadel with a nimble step; when he reached there,
he fell as if struck by lightning: repeated bleedings, purgings, etc.;
he recovered, except for a considerable weakness of the lower
limbs for a rather long time.
This brings us to the description of some functional lesions
of the spinal cord: retention of the urine, violent pains in the
limbs, and, for one patient, paraplegia persisting on the left side;
the pressure was 3 atmospheres.
Let us finally say that slight nasal and even pulmonary hemorr-
hages have sometimes been noted.
I mention only for the record a work of M. Willemin,20 which
is only a simple report of that of M. Francois, all of whose conclu-
sions the author seems to accept, for he does not give any attention
to the theoretical explanations.
The thesis of M. Bucquoy LM is, on the contrary, an original work
of real importance. His observations, as I have said, were made
at the time of the construction of the bridge of Kehl.
At the beginning of his exposition we find a bit of information
from which we shall perhaps later derive some profit, namely,
that the air in the caissons in which the laborers were working
374 Historical
contained on the average (six analyses at different periods) 2.37%
of carbonic acid.
Reaching the study of the physiological phenomena, M. Bucquoy
first describes the pains in the ears.
In regard to the circulation, he gives the following table:
Number Pulse Pulse
of in the during the different periods Increase
Observations open air of the compression
10 77.85 While the air was entering 100.05 22.20
9 77.08 After a quarter hour stay 90.12 13.04
7 75.39 After 25 minutes 86.80 11.41
28 76.05 After a half-hour 81.57 5.32
11 76.59 After 1 hour 83.58 6.99
3 76.50 After 2 hours 83.30 7.00
So, in compressed air, the pulse rate is higher than in open air,
and that is true for all degrees of pressure and especially up to 2Vz
atmospheres. M. Bucquoy, who states here that he disagrees with
the authors who observed the patients, adds:
I have, nevertheless, one observation which seems to confirm
what M. Pravaz says as to the sedative effect of compressed air. One
of my friends, M. Ritter, who went down into the caissons with me
in spite of a very high fever, found that his pulse fell from 95 to 75
after an hour's stay. (P. 24.)
The respiratory capacity also increases, as Pravaz had already
said (see the following chapter) ; the following summarizing table
gives the average measurement of this modification:
Number of Time Respiratory capacity
Observations when they were made in cubic centimeters
103 10 minutes before entering the lockchamber 2950
103 After a halfhour stay in compressed air 3224
103 A quarterhour after return to open air 3075
10 After three quarters of an hour 3004
10 After 2 hours 3000
10 After 10 hours 2980
10 After 15 hours 2950
So the increase, which is constant, and which, as other tables
show, keeps growing up to 2 atmospheres, persists for a fairly long
time after the decompression.
So M. Bucquoy adds with reason:
Showing that this effect is not passing, that it does not cease with
the compression, my experiments make us anticipate the efficacy of
treatments of compressed air for patients whose vital capacity is too
small. (P. 29.)
Diving Bells and Suits 375
In regard to the general phenomena of metabolism, M. Bucquoy,
after analysing all works preceding his and showing their contra-
dictions, at least apparent, declares that he:
Is inclined to believe that in compressed air the respiratory com-
bustions increase; but the bases on which they have tried to establish
this idea lack solidity, and the question must be re-examined.
Dr. Foley 2L> has written an odd pamphlet on our subject, which
is often quoted and praised. He had observed the symptoms of
the caisson-workers at the time of the construction of the bridge
of Argenteuil over the Seine in 1861; the maximum pressure had
not gone above 3V2 atmospheres. I shall begin by quoting a few
of the most characteristic passages in which M. Foley describes
and at the same time explains the phenomena experienced in com-
pressed air:
In the caissons all sounds have a metallic tone which shakes your
brain; and when one speaks, he makes the base of his skull vibrate as
a trumpet would do.
Let us explain these phenomena. By flattening all of our mucous
membrane which is exposed to the air, the compressed air makes" our
pharyngo-laryngial and bucco-nasal cavities larger and more sonorous
through the bones.
Moreover, for the vibration, it gives to the edges of the larynx,
the tongue, the lips, the soft palate, and even the nostrils, tensions
which are greater in proportion to the increase in its density. We
must therefore not be surprised that all these organs raise the pitch of
the sounds which they produce .... Because of the weakness of our
lips, we all lose the power to whistle in compressed air.
Some persons feel that taste and the sense of smell are weakened
or entirely lost in compressed air.
The flattening of the mucous membrane which is exposed to the
air, which makes impossible any hemorrhage of the respiratory tracts
and cures suddenly (though not without pain) coryza and hoarseness,
explains all these data perfectly. How could a withered, shrivelled
organ collect any savors?
Our skin is more substantial than our mucous membrane; in spite
of that the caissons affect it. Its papillae, like those of the nose and
tongue, become less sensitive, and many workmen, whose hands, how-
ever, are very callous, find their sense of touch less sure in compressed
air ... .
In this same medium, our pulse soon becomes filiform and even
imperceptible. The venous pressure soon fails, our circulation flags,
but our tissues do not become livid; the contrary is more likely to
take place.
That is because the great tension of the air, favoring the combin-
ation of the oxygen with the blood, as with all the other combustibles,
makes it so rich that it comes out of our veins as ruddy as out of our
arteries. What loss of color would be possible with such a liquid?
376 Historical
In compressed air, our pulmonary capacity increases, and the
movements of our ribs lessen. The excessive pressure which dissolves
the oxygen in our finest vasculo-sanguine ramifications makes the
action of the thorax unnecessary, and for this reason, our coordinating
nervous center reduces it to its minimum of amplitude.
Economy of strength and time, such is the law which the human
spirit follows in the numerous combinations which it makes to keep
us in harmony with the world, even when it is a matter of our
vegetative life.
The laborers, when they are working in the caissons, feel fatigue
less than in the open air, and do not become so breathless. Hunger
seizes them quickly; they sweat a great deal and yet are never thirsty.
This is the reason for all these phenomena, which are contra-
dictory only in appearance.
The absence of thirst, in spite of enormous loss by sweat, is the
result of the great quantity of water which the compressed air holds
in solution and forces into the organism.
The sweat is due to the assistance which our outer tegument
never refuses to the lungs, especially in a warm atmosphere, when it
is a matter of throwing off much of the muscular materials broken
down by work.
Hunger results from the enormous consumption of our various
tissues by the excess of oxygen which penetrates them and by the
more energetic contractions of some of them.
The lessened breathlessness is caused by the circulatory slacken-
ing which brings back (towards the lungs, the liver, and the spleen)
only a very little venous blood, since there is hardly any, to tell the
truth.
Finally, the absence of fatigue results precisely from the richness
of this same nourishing liquid, which unceasingly repairs our muscles
at the same time that their own contractions destroy them.
In compressed air, our secretions are modified; those of the lungs
and the skin increase considerably. Those of the alimentary canal,
the kidneys and the liver, their converse in many circumstances, do
not change, or rather, generally diminish. (P. 12 and 13.)
When leaving the compressed air, when no illness is to follow,
one immediately has a feeling of comfort. It seems as if one breathes
as if in spite of himself, that one's chest is full of air, and that one
is lighter. That is because there is no longer the heavy weight upon
you. (P. 17.)
Such are the effects produced by the passing action of com-
pressed air. According to M. Foley, the workmen who are frequently
subjected to it experience phenomena of another sort:
Any too long period of work within the caisson is divided into
two stages: one of benefit, the other of organic loss ....
As long as the first lasts, the caisson worker has an increased
appetite, leaves his work without fatigue, and returns to the open air
more alert, more lively, and more eager than usual. He feels stronger
and boasts of it with reason, for then the richness of his blood profits
him.
Diving Bells and Suits 377
As soon as the second begins, the contrary takes place. The work-
man loses appetite, and, more and more, reaches his work as he leaves
it, melancholy and tired. His skin becomes flabby, loses color, be-
comes almost clay-colored. The conjunctiva takes on a wine-colored
hue. His gaze is dull. His face and body grow thin. Indecision, dis-
taste for movement, stupor almost, appear in all his motions, and
gradually the time comes when, outside the caisson, he seems to have
lost strength; when the normal atmosphere is no longer sufficient to
aerate his blood.
In the compressed air, all these painful symptoms disappear;
unfortunately they reappear as soon as he goes out, and more and
more quickly too. Soon even the excess pressure fails to revive him.
He is then on the point of being able to regain the strength he loses,
every time he works, only by the intervention of morbid phenomena.
(P. 18.)
So much for the purely physiological phenomena. As for the
symptoms, the fleas, or excruciating itching of the skin, hardly
ever begin to appear before the pressure of 2.5 atmospheres; be-
yond 3 atmospheres, "everyone has them;" the muscular swellings
(sheep) are frequent at about 3 atmospheres, as are the "synovial
swellings;" but the joints themselves are attacked only later and
more rarely. The muscle symptoms affect particularly those which
have been tired by repeated contractions.
The number of days during which the laborers have worked
in the caissons seems to M. Foley a very important consideration;
under an almost equal pressure, the symptoms would become more
and more frequent and severe the longer one worked.
No fatal ending or paralysis, however, has been observed at
Argenteuil. The most serious symptoms are muscular pains, which,
judging by the details of the observations, seem to have been of
extreme violence.
M. Foley disagrees with all the other authors on two main
points, which are of the highest practical importance. According
to him, in the first place, when the workmen prolong their stay in
the caissons beyond 12 hours, they come out without harm: that
results, he says, from the fact that "the nervososanguine reaction
is general" (p. 49) ; but this so-called explanation is of little im-
portance.
In the second place, curiously enough, he considers that the
speed of the decompression is of little importance. One minute per
atmosphere of compression seems to him long enough:
For pressures above 3V2 atmospheres (decompression in 2 min-
utes 30 seconds), would it be necessary to follow the same progres-
sion? I do not think so; two and a half minutes are a long while in
an icy lock-chamber. (P. 56.)
378 Historical
If one is to use these high pressures, M. Foley advises that
the men be decompressed in "three minutes." Furthermore, he is
so far from the idea that a rapid decompression can be dangerous,
and so persuaded that it is merely a matter of chilling, that he
summarizes his thought by this precept:
If the thick and icy mist which is sure to appear seems too pene-
trating to you, make haste! (P. 53.)
Constructing foundations by the use of compressed air was
used in 1862 on the viaduct over the Scorff, at Lorient, and in 1864,
on the bridge over which the railroad of Napoleon-Vendee crosses
the Loire at Nantes. The chief engineer Croizette-Desnoyers,23
who gives the most minute details about the construction and the
operation of the apparatuses set up by the Gouin Company, does
not mention the condition of the workmen; he is satisfied with
admitting that "at great depths, the system of laying foundations
by the use of compressed air may injure the health of the work-
men." (P. 392)
And yet serious accidents had occurred at the bridge over the
Scorff.
The list of sick workmen, drawn up by Dr. Nail, contains 16
names; the accidents, all due to the compressed air, include: 1 case
of deafness, 6 cases of pains in the joints, 1 of muscular pains, 6
cerebral congestions, 2 deaths.
The two deaths were not simultaneous. The first occurred
March 17, 1862; the workman died "of asphyxia on leaving the
caisson;" the second, June 3, in another pier; the medical note
says: "died after four hours of cerebral congestion and asphyxia."
I could get no details about either the symptoms which pre-
ceded death or the results of the autopsies, if there were any, or
even the pressure reached. I know only that the decompression
was made regularly in 10 seconds and that the maximum exca-
vation for the first pier was 18 meters, for the second only 12
meters.
There were, therefore, 8042 shifts of workmen, among whom
there were only 16 accidents serious enough to be noted. Other
workmen who were in the lock-chamber with the two victims
experienced no symptoms.
This double disaster was the cause of a court summons against
the company officials, accused of homicide by carelessness; they
were acquitted by the court of Lorient (September 30, 1862) and
by the court of Rennes (December 11, 1862). The preambles of
of the judgment and the decree are very interesting, because they
Diving Bells and Suits 379
reveal the vague ideas of the doctors about the real cause of the
accidents, and these uncertainties inspired the acquittals given:
Another accident, followed by another court instance, took
place at the bridge over the Scorff. M. Gallois, civil engineer, an
agent of the company, who went down into the caissons May 12,
1862, on his return to open air was attacked by symptoms of
paralysis "as a result of cerebro-spinal congestions, spells of dizzi-
ness, and nervous shocks," so that he had to be sent to a watering-
place; he died two years afterwards.
His request for damages was refused by the tribunal of the
Seine (August 18, 1861); the Orleans company produced an
opinion of M. Dufaure, which reveals, like the legal documents
which I mentioned a moment ago, the uncertainties of medical
science. The celebrated lawyer combats the opinion of Pol and
Watelle about the necessity of making the decompression very
slowly with that of M. Foley. The tribunal gave no decision as to
the scientific question, but declared that Gallois had not received
an order to go down into the caisson, and that consequently the
company could not be held responsible.
Here is the condition in which Dr. Hermel,"4 a homeopathic
physician living in Paris, found M. Gallois, who had him called in
consultation a few days after the accident:
May 21, 1862, we were called in Paris in the case of M. Gallois,
a civil engineer, aged 24. We found the patient suffering from incom-
plete paralysis of the lower limbs, permitting him neither to stand
upright nor to walk without support; he could advance only in a very
awkward manner, placing both hands on all the surrounding objects;
the movements of his limbs were irregular, jerky, trembling; he
dragged his feet; if he tried to stand upright, a violent trembling
immediately shook his legs and forced him to sit down. After three
or four steps, the same convulsive trembling stopped him, because it
kept increasing and would have made him fall. Over his whole body
cutaneous sensitivity was exaggerated, it was hyperesthesia, the skin
was the seat of an annoying pruritus, without any trace of an erup-
tion. The movements of the tongue were so difficult that the patient
could not pronounce all the words distinctly. Both memory and
ideas were confused. As a result of the suffocation, a frequent
cough tired him when he talked and produced a profuse expectoration
of mucus with the appearance of the white of an egg. Auscultation
of the chest and percussion showed that the lungs, though permeable
to air in their whole extent during deep inspirations, did not possess
their full elasticity; one could hear, especially on the left side, the
expansion of the pulmonary vesicles beginning and stopping suddenly
before the movement of inspiration was finished. This expansion of
the pulmonary vesicles was therefore incomplete, which hampered
normal respiration. The abdominal functions were interrupted; the
380 Historical
constipation could be overcome only by enemas; there was paralysis
of the rectum. The bladder was also paralyzed; urination could take
place only by use of the catheter. He had lost appetite, and the cough
often caused vomiting.
Knowing the perfectly regular life of this young man, we asked
him about the date and the mode of onset of this disease.
He told us that while he was employed at the railroad works at
Lorient, he had gone down into a caisson under a pressure of three
atmospheres (including the outer pressure), where he had remained
three hours to check the progress of the work in the foundation of a
pier. Three or four minutes after his exit, he felt an icy cold, sudden
and penetrating, as a result of the enormous rarefaction of the air in
proportion to the inner pressure. When he tried to wash his hands,
he perceived that movements of the arms were impossible, he could
not put his hands into the tub because he could not lift them higher
than his waist.
Taken home by two men who supported him under the arms and
placed his feet on the steps he had to descend, he went to bed; after
four or five hours he wished to get up, but he was completely paral-
yzed. An energetic treatment was given him and made him able to
come to Paris after a fashion. On the tenth day he was in the
condition which we described above.
For ten days we gave belladonna (twelfth) and bryonia, which
checked the cough a little. June 2, we began to apply every other day
the rheophores of an electro-galvanic machine over the hypogastrium,
to overcome the paralysis of the bladder. After the third treatment,
he began to urinate without the catheter, but the next day, he was
forced to have recourse to it again. After the fourth treatment, he
urinated voluntarily only during the day. After the fifth, the urine
resumed its natural course. The constipation persisted. We electrified
the walls of the abdomen and the anus. Defecation, although some-
times difficult, was reestablished about the eighth treatment. After
the tenth treatment, the abdominal organs had gained strength and
activity, especially on the left. The right leg was still dragging, and
in certain positions it was still affected by convulsive trembling; he
could not have stood up on one leg; he used a cane in walking.
In July, he went to the baths of Balaruc, from which he returned
August 1. His condition was improved, but there was still a faltering
in the right leg. The cough persisted, although not so bad; respiration
was still incomplete. Soundness of speech, ideas, and memory was
reestablished. He no longer experienced pruritus or hyperesthesia
of the skin. Six more applications of electricity caused a great im-
provement in the movements; he could walk without support.
Today, January 12, that is, after eight months of treatment, he
has at times tiring fits of coughing; his respiration is almost normal,
he becomes breathless if he walks too far or too quickly. He walks
without support, but there is still stiffness in the right leg, and we
cannot say when he will be completely cured. (Vol. XVII, p. 198-200.)
Also in 1862, a bridge was constructed over the Adour, in
Bayonne, in the construction of which the pressure had to be
Diving Bells and Suits 381
raised to more than 4 atmospheres. The civil engineer who super-
vised the work, M. Counord, twenty years old, who up to that
time had felt no symptom, on December 31, a few minutes after
leaving the lock-chamber, in which the decompression had been
made in 4 or 5 minutes, was attacked by vertigo, dizziness, and
complete loss of consciousness. The pressure was 4 atmospheres,
the length of the stay in compressed air was one hour; the day
before, he had remained in the caisson for two hours. Three hours
afterwards, when he regained consciousness, he was completely
paralyzed in both sensation and movement in the lower limbs,
with loss of sensation in the arms.
The detailed observation of the beginning of this strange case
was given by Dr. Limousin,25 of Bergerac, who does not hesitate
to attribute the symptoms to a hemorrhage of the spinal cord:
I called upon M. C, who had been brought from Bayonne to
Bergerac, on January 12, 1863: complete paralysis of the lower limbs,
involuntary excretion of the feces! and urine, normal sensitivity
everywhere, a little exaggerated in the lower limbs; if they were"
struck suddenly, or touched with a cold body, a sudden extension
was produced. Intelligence normal. In the epigastrium and the hypo-
chondria, pains which were checked by the application of morphine
on the bare skin. Up to January 20, two doses of cathartic were given;
nothing new appeared except very painful convulsive movements of
the abdomen.
January 28. Excruciating pains appeared yesterday in the belly;
it is flaccid, pressure does not change it. The patient's condition is
terrible: constant moaning, voice faint, cold sweat, face cadaverous,
pulse imperceptible, 48. Dry cuppings, enemas with laudanum have
no effect. I then prescribed 20 centigrams of extract of opium in four
pills, one every hour.
On January 29, with the second pill, the pains stopped; the
patient fell into a profound sleep; he awoke quite free from pain. In
the first few days, a small erosion had formed on the sacrum, today
there was a huge scab; the buttocks, and the lumbar region were dull
red; the patient could lie only on his back.
February 20. The sore on the sacrum, sprinkled with gray cinchona
bark, has shrunk to the size of a 5 franc piece; it is pink and granu-
lated; painful contractions have yielded to the application of metallic
armatures. Movements can be made by the paralyzed limbs; they are
executed more freely on the right side; on the contrary, sensitivity
is very dull on the right, and keener on the left side in the same parts;
there are formications over the whole body; one day sight was entirely
gone for a few instants; erections, rare at first, have become more
frequent. Finally defecation and urination are voluntary.
It is hard to find a better example of medullary apoplexy: sudden
attack, lesions of contractability, sensation, a special sense, and the
eye; reflex movements caused by the slightest stimulus; great lowering
of the vitality of the tissues, manifested by the rapid mortification of
382 Historical
the regions sustaining the weight of the body; finally, erections not
accompanied by any stimulus of the genital impulse. There was never
any considerable sensitivity along the spine.
The improvement did not make very rapid progress. In May,
1870, M. Counord took several steps without support; he still had
very unusual reflex movements when his lower limbs were
pinched; the sensitivity of the left leg was much diminished. I
saw him again in May, 1876; he could climb one flight of stairs with
great difficulty and with the aid of an arm; formications in the
upper limbs seemed to indicate a morbid action in the upper
regions of the spinal cord; the functions of urination and defecation
had become normal again.
A few days later, a terrible accident, in which three men died,
saddened the Bayonne works; the caisson had burst, as happened
at Douchy, and later at Chalonnes. The suggestion 26 was made
that the death of the workmen had been caused by the decom-
pression; that is probably a mistake, as is shown by the following
extract . from a letter written me by the engineer Bayssellance,
who was kind enough to make a little investigation of the matter,
at my request:
The pier, being deeply imbedded in the sand, measured in all
more than 30 meters from base to the water level. The inner pressure,
therefore, was about 4Vi atmospheres. The upper surface, not being
constructed with a view to such a high pressure, buckled perceptibly:
this buckling caused a deformation of the cast-iron cylinder of the
equilibrium chamber. One of the bolts having yielded to the uneven
tension, a shock was produced which made the whole upper part of
the equilibrium chamber fly to pieces. The decompression in this
small portion of the apparatus was therefore sudden; in the interior
of the pier, the capacity of which was 200 to 300 cubic meters, it
must have been more gradual, and brought a violent current of air
upwards from below, bringing with it the planks and the sand of the
resting stages.
According to the foreman, the results were quite different from
what was reported. No man was killed by the change of pressure.
Since the wet sand from the bottom was no longer restrained, it
rose rapidly, reached and passed over one of the men who was climb-
ing the ladder; he was found seventeen days afterwards when the
caisson was being cleared out, clinging to the ladder rungs in the
position of climbing. Another was carried away by the air current
and found himself at the top without really knowing what had hap-
pened to him. Two others who were on the intermediary stages were
carried up and crowded against the under side of the floor of the
equilibrium chamber, and were almost suffocated, with their mouths
full of sand; they were taken to the hospital, and died the next day,
I think. Finally, five men who were in the equilibrium chamber itself
Diving Bells and Suits 383
were covered with sand, which even penetrated the skin, and remained
for a few moments as if stupefied, but none of them was seriously ill.
This result does not agree with what had been told me; but M.
Wolff was on his rounds at the moment of the accident; and M.
Counord was ill; it seems more certain to trust the version of a witness
though it is almost the opposite. Moreover, this man was present at
a similar accident, at the time of the construction of the bridge of
Bordeaux; there too, no death was caused by the sudden decom-
pression; two men only were killed by fragments of iron.
But if a sudden decompression of more than three atmospheres
was not fatal, this change, though moderated by a stay of 4 or 5
minutes in the equilibrium chamber, was none the less dangerous in
the long run. According to M. Counord, 90% of the workmen were
ill, all attacked by violent pains in the joints, oppression, disturbance
of vision, etc. The foreman whom I saw was attacked three times,
and suffered greatly, but never more than a day. One morning, out
of eleven men who were leaving, nine were seized with pains after
a few moments.
Certainly it is not impossible that the decompression had some-
thing to do with the death of the two workmen who were buried
in the wet sand; but that is not proved. The strangest thing in this
observation is to see men experiencing almost no symptom after
an instantaneous decompression from at least 4 atmospheres.
In 1865, there was a similar foundation under the Louet, at
Chalonnes (Maine-et-Loire) , for the bridge of the line from Angers
to Niort. A catastrophe as yet unexplained killed two workmen:
February 20, 1865, when pier number 2 had reached bed rock,
at a depth of 14 meters below the low-water mark, when everything
seemed finished, when the work-chamber was already filled with
concrete, and when the caisson, like a chimney, was also filled up to
a depth of 5 meters, suddenly a violent explosion occurred and half
of the metal roof of the equilibrium chamber " was hurled about 30
meters away. Two laborers, who were in the work-room, were
crushed. No explanation for this terrible accident has yet been found.
(Lectures on Bridges by M. Morandiere)
It is probable that in this case, for some unknown reason, the
tension of the compressed air had risen far above that required by
the depth reached; the force of the explosion proves that.
I am endebted to Dr. Gallard for some interesting details about
this distressing accident:
The death of the two workmen (this learned colleague writes me)
was almost instantaneous, like a thunderbolt for one of them, a little
slower for the second, who still breathed for a few seconds, but had
already lost consciousness.
The autopsy (made by M. Gallard under bad conditions, after
exhumation and previous autopsy by the physician of Chalonnes)
384 Historical
showed numerous patches of interlobar and vesicular emphysema on
the lungs of the two victims. There were besides numerous ecchy-
moses in spots under the pleura and the pericardium .... I seem to
remember that the blood .... contained a few bubbles of gas .... The
notes of the autopsy were lost by the physician of Angers to whom I
had dictated them.
Should we attribute the death to the decompression? It is hard
to decide, in view of an unsatisfactory autopsy and especially the
fact which we reported above in discussing the bridge of Bayonne.
M. Triger was disturbed by the accidents caused by the appli-
cation of his method, and sent to the Minister of Public Works a
Memoir on this subject, which was submitted to the examination
of MM. Combes, Hennezel, and Feline-Romany.
The report 2S of these engineers, after briefly reviewing the
works carried out by the Compagnie du Midi over the Tech, at
Bordeaux and Bayonne; by the Compagnie de l'Ouest at Argen-
teuil, at Elbeuf and at Orival over the Seine, at Briollay over the
Loire; by the Compagnie d'Orleans over the Scorff at Lorient, over
the Louet at Chalonnes, and over the Loire at Nantes, states that:
The accidents to which laborers working in compressed air are
exposed rarely endanger their lives, cause only rather short inter-
ruptions of work, and, especially, are very few, compared to the
number of men passing through the lock-chambers in each job.
The diseases caused by these accidents can be prevented by the
use of the means specified in the course of this report.
These means are the use of woolen garments in the lock-
chamber and a decompression for which no uniform rule could be
given:
There is no rule to be observed other than the one which common
sense indicates, namely, not to open the cock too quickly, for com-
pression as well as for decompression, so as to give the organism time
to place itself in equilibrium with the medium in which it is immersed.
M. Triger requires that the decompression last 7 minutes, and
states that then the symptoms disappear completely. It seems to us
that this time should vary with the constitution of the workman.
(P. 125.)
The excavation of the shaft of a coal mine at Trazegnies, in
Belgium, at about this same time, was the subject of a very inter-
esting work by M. Barella.29
The total maximum pressure was 3V2 atmospheres. The decom-
pression was made in about 20 minutes.
According to M. Barella, in addition to pains in the ears one
experiences:
Diving Bells and Suits 385
Dryness of the pharynx, a considerable decrease of the urinary
secretion, a sensation of respiratory improvement, for it seemed to
me that I had never breathed so freely, and so easily.
As for the pulse, we did not obtain a very definite result; how-
ever, in most of our workmen, it seemed to us that the rate had de-
creased by a few beats. (P. 598.)
The symptoms observed were:
1. In seven workmen, epistaxis, not serious;
2. In eleven workmen, pains in the thoracic and abdominal
members, sometimes crushing, lancinating, excruciating.
3. Severe itching on the legs, unaccompanied by pain, a very fre-
quent symptom. (P. 605.)
M. Barella calls attention to the fact that none of these symp-
toms occurred during the stay in compressed air; they were ob-
served only when the workmen were leaving the apparatuses.
Moreover, they began to appear only above 2.8 atmospheres.
M. Barella says that the little wounds which the laborers
inflicted on themselves while at work did not bleed, "which is
explained by the pressure on the cutaneous teguments."
A student at the School of Mines of Liege, who went down
into the shaft April 15, experienced' on his exit very serious symp-
toms, which he describes himself in the following words:
During the decompression, I felt a discomfort which I attributed
to the cold.
After I had come out, when I wished to raise my right arm, I
could not make it reach a definite point without making the effort
two or three times. My sight was affected, and I saw my arm moving
much as one perceives objects after he has whirled about several
times.
The paralysis grew worse and it became impossible for me to
move my arm which hung inert, I could not even make motions with
my hand. The phenomenon was rather like that of an arm which has
gone to sleep. It appeared progressively and in the same manner in
my right leg.
They placed me on a bed, for I could not walk, I sank down.
They rubbed me. I was dazzled and my eyes refused to serve me at
all. I saw only at long intervals, and for a second at the most, then
everything disappeared to reappear only after a few moments in the
same way. My eyes were dull and glassy, they told me, and perceived
only a white, vaporous light.
I recovered the use first of my leg, then of my arm; the instants
during which I could see grew closer together, and I saw distinctly
for longer periods.
Finally no symptom was left except a violent headache and the
usual signs of a fit of indigestion. I threw up my food. My headache
disappeared in the open air, and I went home, having nothing but
fatigue to remind me of my former experiences.
386 Historical
The friend who accompanied me, who had eaten the same meal
as I, had no unusual sensation. (P. 612.)
Among the conclusions of M. Barella, we shall quote two:
1. It is best not to go beyond a pressure of three and a half
atmospheres above normal pressure.
2. We may take as a standard of the duration of the decom-
pression 10 minutes per atmosphere.
The others have only a purely medical interest: lymphatism,
heart ailments, etc.
In America, the first bridge constructed by compressed air was
over the Great Peedee River, for the railroad from Wilmington to
Columbia and Augusta. I have found in my reading no information
about this work from the point of view which interests us here.
In 1869, a truly gigantic work was undertaken at Saint Louis
(United States). A bridge with two piers was built over the
Mississippi. On the east pier, the depth reached was 33.70 meters
below the usual water mark; it was a depth without precedent in
the applications of the method, which was to be increased by the
occasional floods of the river. The total pressure rose to 4.45 at-
mospheres. The total number of workmen employed there was
352; about 30 were seriously affected: 12 of these died.
Here is an extract from the report made by the chief engineer
of the work, M. Eads:30
When the depth of 60 feet was reached, some of the workmen
were affected by muscular paralysis of the lower limbs. It was rarely
painful, and went away in two or three days. As the caisson sank
deeper, the paralysis went away more slowly. In some cases, the arms
were affected, and more rarely the' sphincters and the intestines. The
patients also had much pain in the joints when the symptoms were
very severe. Nine tenths of the patients felt no pain and got well
very quickly.
The duration of the stay in the air chamber was gradually short-
ened from 4 hours to 3, to 2, and finally to 1 hour. The use of
galvanic plates or rings seemed, in the opinion of the director of
construction and the workmen, to give a remarkable immunity against
attacks. Finally, they all had them. They were made of alternate
rings of zinc and silver, and placed on the chest, the arms, the elbows,
the waist, and under the soles of the feet. The acidity of the perspi-
ration was sufficient to establish a galvanic current, and the opinion
of those with the greatest experience in these matters was quite
favorable to this remedy. Captain Eads is strongly inclined to believe
it to be valuable
The engineers of the port, who very often visited the caisson,
have never been ill.
Physicians have differed greatly about the cause of the symptoms.
Diving Bells and Suits 387
Some maintained that a slower return to normal pressure would have
been less dangerous; others blamed too rapid compression for all the
trouble. The fact that the workmen employed to operate the doors
were never affected, although during the two hours of their work they
were very frequently in extreme and alternating conditions of pres-
sure — one moment at normal pressure, and 5 minutes afterwards
sustaining a weight of 50 pounds per square inch of the surface of
their bodies — would seem to prove that these two theories are wrong,
and makes us believe that the real cause of danger lies in the long
duration of the stay in this air where the body endures so great a
pressure, and not in the rapid changes to which it is exposed
The transitions lasted from 3 to 4 minutes
Considering that thousands of persons, even delicate ladies, had
visited the air chambers for a short time without harm, after the
caisson had reached bed rock too, and that no serious symptom
attacked the workmen after the reduction of the working time to 1
hour, M. Eads concluded that the real cause lay in the prolonged
labor .... Too long a stay was invariably followed by paralysis. Dr.
Jaminet, physician at the job, after staying one day for 2% hours
when the depth was 90 feet, was severely affected after returning
home.
Dr. Bauer,"1 surgeon at the City Hospital, to which were taken
the 25 workmen affected during the laying of the foundation of
the Saint Louis bridge, presenting what he calls "Bridge cases,"
gave some interesting information about the symptoms observed in
these patients:
Respiration becomes more laborious, and the pulse more rapid at
the beginning of the compression, which passes off rather quickly in
persons who are in good health. The voice takes on a nasal tone
which it retains even after leaving the compressed air.
When they leave, all the workmen are very pale and extremely
weary, even to the point of stretching out on the ground. In others,
one sees involuntary, choreic muscular contractions with bleeding from
the nose and lungs.
In serious cases, there is paralysis in different degrees, from slight
paresis to a complete loss of movement and sensation.
Very often, urination is rendered difficult or wholly impossible,
so that the urine must be drawn with a catheter: it is often bloody.
Respiration is not affected; fever rarely appears and then it brings
on a fatal ending. Death occurs in a state of coma, with delirium,
hiccuping, stertorous respiration, and muscular cramps; the pupils are
dilated towards the end
Among the patients observed, only a few were cured in the course
of the first week; others remained under treatment for a month; four
died. In the paralytics, there are found congestions of the cerebral
and medullary meninges, edema of the arachnoid, softenings of the
brain and the spinal cord without definite localization. In one case,
the softening covered the anterior horns and lateral column the whole
338 Historical
length of the spinal cord. Baumgarten found in this focus abundant
cells of the neuroglia attacked by fatty degeneration.
The same facts were told by the chief engineer of bridges and
highways, Malezieux,32 in his fine report on the public works of
the United States of America in 1870. He copies verbatim (p. 91-93)
the passage from the report of the engineer Eads which we quoted
above.
M. Malezieux has also given details about the foundation of the
bridge which was to connect New York to Brooklyn. At the time
of his visit, they were only at the beginning of this work. But the
plans were gigantic; the foundation caisson was 52.46 meters long
by 31.11 meters wide, that is, more than 16 ares in area.
In the second Memoir,33 M. Malezieux gives the depth actually
reached. The Brooklyn pier had a foundation 15 meters deep; the
New York pier, 24 meters.
For the latter, steam-heating was installed in each of the air-
locks, so as to prevent the chill produced by the sudden escape
of the compressed air (p. 385.)
As to the physiological effects, M. Malezieux states:
That he has little to add to what he reported previously about
the Saint Louis bridge. M. Roebling (that is the engineer and con-
structor), however, notes this fact, that the action of the lungs is
changed involuntarily in compressed air; the number of times one
breathes in a given time is reduced 30 to 50 per cent; which would
indicate that the organism reacts against the introduction of oxygen
in a proportion two or three times greater than in normal atmosphere.
The natural conclusion to be drawn from this observation is the
one which M. Eads had made at Saint Louis; to shorten the duration
of work in compressed air as the pressure increases. (P. 395.)
I shall quote in conclusion some information which I owe to
the kindness of the managers of a great industrial company, which
does a great deal of work on the foundations of bridges with the
use of compressed air. These documents refer to works executed
very recently outside France; a discretion the motives of which
everyone will understand prevents me from giving more definitely
the details of date and place.
First, here are general specifications about the manner in which
the works were carried on, and which resulted in the accidents;
these specifications come from the superintendent of the job him-
self:
1. At a depth of 20 to 22 meters, the shifts still lasted 8 hours,
and our men were not too tired, none of them felt any ill effects
from the pressure, they were merely inconvenienced by the evil
odor of the mud and by the hot air, which, however, we took care to
Diving Bells and Suits 389
renew frequently through the hoisting-shaft; under this pressure of
two atmospheres, the workmen underwent decompression in 4 or 5
minutes.
2. From 22 to 25 meters, the shifts lasted 4 hours; under this
pressure, the men began to feel rather severe symptoms; the decom-
pression took 10 minutes, the opening of the discharge cock was only
25 millimeters, then afterwards 18 millimeters.
3. From 25 to 28 meters, the workmen relieved each other every
3 hours, and were decompressed by means of a cock, the opening
of which was reduced to 10 mm.; it took 16 to 17 minutes, and it was
while working under this pressure, that our men were most fatigued;
very often it happened that 4 out of 7 were affected by the pressure
in their legs, heads, and stomachs; in others, the decompression caused
paralysis of the bladder or of vision; some of these workmen expe-
rienced horrible sufferings for two or three days and then three or
four days of convalescence before being able to go back to work;
these were the ones most seriously affected; as for those who had
lighter attacks, they also experienced great pain for twenty-four hours
and then 1 or 2 days of inability to work. (July 22, 1875)
As a sequel to my letter of the 22nd, I wish you to know that in
the last four days we have had only two workmen affected by the
pressure; only slightly, but enough to keep them from working; we
still have in the hospital 2 workmen seriously affected by the pressure
since the 21st on coming off duty at 6 o'clock in the evening; they
are paralyzed in the lower parts of their bodies, and their urine must
be drawn by the catheter.
The decompression lasts on the average 18 minutes; the shifts
work 3 hours. (July 28)
To continue my letter of the 28th of this month, I wish to inform
you that a man named R, one of the two working in the excavation
who were hospitalized as a result of the pressure, died today at half
past twelve. The second workman is out of danger, the doctors think;
he has recovered except that his legs are paralyzed, and they hope
that this trouble will soon clear up.
The doctors claim that the death of R. is due to the pressure,
which probably affected the spinal cord; this man had worked before
in excavations with compressed air, but had never gone beyond 2.1
or 2.2 atmospheres. (July 30.)
The first of the two workmen who were seriously affected and
whom we have just discussed returned to his home; we have had
no further information about him.
As to the said R., his autopsy was performed. It resulted in
noteworthy findings which Dr. L. describes in a letter addressed
i the company, and a translation of which follows:
r
After opening the spinal canal, I found that at the height of the
thoracic vertebrae the spinal cord was very soft; for some inches it
was transformed into a soft, flowing mass, yellowish gray in color,
which above and below merged into the healthy part.
390 Historical
The cord in general was much congested, as was the brain, but
I saw nothing else abnormal, there or in the other organs.
3. Diving Suits.
As we said when we began this chapter, the diving bell has
been entirely abandoned for the diving suit, an apparatus which
is infinitely simpler and less costly, and which allows each man to
work by himself with a certain liberty.
I have no intention of going back to the origin of this invention
although it is very recent; the French word itself scaphandre
(o-Ka'/'os, boat, avSpos, man) dates from the end of the last century,
and was given to a simple life preserver. It is only during the last
fifty years that Siebe of London, then M. Cabirol, and finally MM.
Rouquayrol and Denayrouze have made a practical apparatus of
it, easy to use in fishing for oysters, coral, pearls and sponges, in
saving sunken objects, in cleaning and inspecting the hulls of ships,
etc.
However, I cannot keep from mentioning a strange invention of
Borelli, which had some connection with the diving suit and is
interesting in the history of the theories of respiration; I borrow
the description of this apparatus, very poorly planned because it
did not provide for renewing the air for the diver, from Brize-
Fradin who quotes it without telling where the celebrated doctor-
mathematician described his apparatus. He expresses himself in
these words:
Borelli, inventor of the machine called diver's bladder, prefers
it, for some reason or other, to Halley's bell. It is a globe of brass or
copper about two feet in diameter, placed over the head of the diver;
it is fastened to -a goat-skin garment made to fit the diver. In this
globe are the tubes by which the circulation of the air is maintained;
at his side the diver carries an air-pump, by means of which he can
make himself heavier or lighter, as fishes do, compressing or expand-
ing their air-bladder: in this way he thinks he can meet all the objec-
tions made in regard to other machines, and especially the objection
in regard to lack of air, since the air which has been breathed is,
according to him, deprived of its harmful qualities by circulation in
the tubes. (P. 44.)
Let us recall that in Halley's diving bell a man could take
several steps outside the bell and continue to breathe by means of
a sort of helmet and a tube which ended in the air of the bell; he
was therefore almost in the conditions of the modern diving suit.
The principal part of the present apparatus (Fig. 7) consists of a
heavy metal helmet, with glass portholes, which the diver places
over his head; a tube which communicates with a compressing
Diving Bells and Suits
391
pump placed on the bank or on the deck of the boat furnishes him
compressed air which escapes through orifices contrived for this
purpose. The pressure to which the air breathed by the diver is
Fig. 7 — Diver equipped with the Denayrouze regulator, complete suit.
subjected is therefore practically equal to that which the water
exerts on the rest of his body. This condition absolutely must be
met, as we shall see in the following part of this work, and very
392
Historical
serious symptoms must have been the result, under certain circum-
stances, of forgetting this fundamental rule.
It is scrupulously observed in the apparatus of MM. Rouquayrol
Fig. 8— Diver equipped with the Denayrouze regulator, helmet removed.
and Denayrouze. The diver dressed in their suit does not breathe
directly the air furnished him by the pump; on his back there
is a metal reservoir in which the compressed air is constantly
Diving Bells and Suits 393
stored up and from which, thanks to a very ingenious mechanism,
it escapes only to meet the needs of the diver at the pressure
absolutely necessary at the depth reached. When the reservoir is
full, the diver can detach the tube which leads to the pump, and
move about freely for a certain time. He can even, for work of
short duration, remove the helmet and take in his mouth the tube
which comes from the regulator (Fig. 8) .
To return to the surface, the divers sometimes climb a rope
ladder, and sometimes are hoisted on board by means of a rope
fastened to the belt. In both cases, they hardly ever take more
than one or two minutes to return to normal pressure.
The diving-suits are now used very frequently in all our sea-
ports; but the depths reached are generally rather shallow and do
not exceed 20 meters. They are also used considerably in the seas
of the Archipelago for sponge-fishing. There, the depths reached
are as much as 40 meters; I even have it from M. Denayrouze that
divers have reached 48 meters; in that case the total pressure was
therefore 5.8 atmospheres.
According to M. Leroy de Mericourt, divers with suits in the
employ of English companies have ventured to the depth of 54
meters, the pressure therefore being 6.4 atmospheres.
It is not with impunity that such pressures have been endured,
or to speak more exactly, it is not with impunity that divers have
risen from such depths in a few minutes to the surface of the
water. Many accidents have been reported, a large number of
which have ended in death. Their frequency and their severity
are such that the accounts telling us of them seem to scorn and
omit whatever does not amount to paralysis or death. However,
the financial returns are so great that the use of suits keeps
increasing every year. They were introduced only about twelve
years ago in the Archipelago, where their appearance caused
regular riots in 1866; and in 1867, about a score of machines were
operating in sponge-fishing. I have been told that today there are
more than three hundred of them,— and that the deaths have risen
to about thirty per year!
The first document which informs us of these strange and
dangerous accidents we owe to M. Leroy de Mericourt,34 and bears
the date of 1869. This article is based, the author says, on infor-
mation contained in an unpublished memoir of M. Auble, agent
of the Society for sponge fishing by means of the Rouquayrol and
Denayrouze diving apparatuses:
During the 1867 cruise, no serious accident occurred among the
men who were equipped with this apparatus for fishing. But in the
394 Historical
same season, out of 24 men who used 12 suits of English manufacture,
10 died.
The lack of doctors at the fishing places and the difficulty of get-
ting information from the fishermen of the Archipelago, who are of
a very distrustful nature, did not allow us to determine, as would
have been desirable, the nature of the symptoms which preceded the
death of the 10 men we have just mentioned. We could learn only
that three of them died suddenly as they were leaving their subma-
rine work, and that others had languished from one to three months,
paralyzed in their lower limbs and bladders. Because of the existence
of paraplegia in the 7 divers who lived for a time, we may assume,
up to a certain point, that this symptom must also have been present
in the 3 who died rapidly.
What are the injuries which caused the death of these unfortunate
fishermen during the cruise of 1867, and how can we explain the
mechanism of their production? The lack of medical observations
and especially of autopsies requires that we express an opinion on
this subject only with considerable reserve. Paraplegia, it is true, is
a symptom so characteristic and apparent that one does not need to
be a physician to observe it. In one of the victims, a very daring
young Greek diver, there was such a distention of the bladder that
the father, in the hope of relieving this unfortunate young man,
tried to catheterize him; he caused disturbances which were followed
by a peritonitis which was soon fatal.
We shall see in Chapter III the explanation which M. Leroy de
Mericourt suggests for these symptoms, which he attributes to
medullary hemorrhages.
The rest of the note is devoted to very accurate remarks about
the superiority of the Denayrouze apparatus and the necessity of a
slow decompression:
Whereas the group of divers among whom the symptoms appeared
reached the considerable depths of 45 to 54 meters and consequently
endured pressures varying from 5V2 to 6.4 atmospheres, M. Denay-
rouse with a prudence which does him honor, had given the order not
to go beyond 35 meters, not to stay more than 2V2 hours, per diver
and per day, and finally to come up very slowly, taking one mmute
for each meter of depth. Moreover, the apparatus used offers greater
safety than the diving suit: the air is given out in proportion to the
needs of respiration, and at a pressure mathematically equal to that
of the ambient medium.
But it was not possible to make the Greeks observe these strict
precautions. The decompression to which M. Denayouze had as-
signed a duration of 15 minutes began to be made in one or two
minutes again. The symptoms reappeared also. A private letter
from M. Denayrouze, dated July 9, 1872, gives me the following
information on this point:
Diving Bells and Suits 395
For 6 months, I have had about a hundred men diving at depths
varying from 30 to 40 meters. 200 other foreign divers were working
under my supervision under the same conditions. All these men were
breathing air at the pressure of the ambient medium, about 4 or 5
atmospheres.
Five men died at these pressures, a great many others were
attacked by different affections, the most frequent of which were
paralyses of the lower limbs and the bladder, deafness, and finally
anemia.
The men subjected to sudden decompressions were really more
affected by the symptoms than the others. Those who died never
expired at the bottom of the water, they came up complaining of
inward pains, particularly of the heart, lay down in their boat, and
died after a few hours.
July 19, 1872, a young doctor who in 1868 had made a cruise on
board a boat bound for sponge fishing on the coast of Turkey,
Alphonse Gal,35 sustained before the Faculty of Montpellier a very
interesting thesis on the data which he had observed.
In the first part of his work, he discusses the modifications in
the physiological functions caused by a stay in compressed air.
Naturally I am reporting only the part of the observations which
come from his experience.
Speaking first of respiration, he says:
It is impossible to use a spirometer in a diving suit; and it is rather
difficult to appraise sensations of the type that we were studying.
However, at pressures varying from 15 to 25 meters, I observed myself
from the point of view of respiratory movements and I think that the
expansion is less than in the normal state. No doubt the pulmonary
capacity, which M. Bucquoy calls the vital capacity, increases, in the
inspirations in which the lungs are called upon for their full strength;
no doubt when one is making an experiment and tries to produce the
fullest expansion, the results are better in the compressed air; no
doubt also the patient subjected to the air treatment and quickly
experiencing a sensation of well-being "due to the greater efficiency
of hematosis, instinctively takes deeper inspirations; but the diver,
subjected to a pressure of 2, 3 and 4 atmospheres, does not feel the
necessity of increasing his pulmonary expansion, and like Foley, I
believe in the action of the nervous centers in moderating the extent
of the inspiration, since this extent has become useless because of
the greater quantity of oxygen brought in contact with the capillaries
of the pulmonary plexus in a volume which merely equals the normal
volume.
And so in summary, for forced respirations the pulmonary capacity
increases with the atmospheric pressure; but for ordinary inspirations,
especially in a healthy man, this rule no longer holds, for one is more
likely to observe — at least I think I noted it, especially at pressures
of 2 to 3 atmospheres — a decrease in the pulmonary amplitude (P. 17).
In regard to the number of respiratory movements:
396 Historical
For my part, I have been able to make a rather large number of
observations on this point; when a diver was on the bottom a short
distance from the boat, and when the sea was calm, I clearly saw
the bubbles of air from each respiration coming to the surface. As
one could see in the description of the regulating air bag, the diver
with the Denayrouze suit breathes through his mouth air contained in
a reservoir, and he expires also through the mouth. The air thus ex-
pired escapes through a valve which closes immediately after the
expiration. The time separating two respiratory acts can therefore be
measured in this way, and during this time the diver is under the
normal conditions of work and does not know that he is being
observed. I have thus been able to note individual differences, but
within very narrow limits. The minimum number of respirations was
12; the maximum 30; but we should not think that the average is the
number halfway between these two numbers. Taking all the obser-
vations I have made, the average is 18, but it is too high and cannot
give the normal number of inspirations in compressed air. In fact,
every time I observed in a diver a respiratory rate higher than 20,
I am sure that this respiratory acceleration resulted from a chance
cause (emotion, muscular effort, rapid walking, etc.). In many cases,
after following the respiration of the diver for a few minutes, I saw
it dropping little by little and finally getting below 20.
In summary, the physiological modifications of the respiratory
apparatus affect the extent and the rhythm of the movements. Let us
add to what we have said on this subject that respiration is always
very easy in compressed air. In this we agree with all who have
carried on experiments under good conditions of ventilation. Under
the water, whatever the depth, one breathes easily and freely (P. 19) .
We have seen in divers that the respiratory movements increase
in number as the men ascended the ladder and were consequently
decompressed. A great part of this acceleration must no doubt be
attributed to the very act of decompression, for the ascent is extremely
easy for the divers; and because of the air contained in their suit,
which expands as the ascent continues, they need rather to hold
themselves down than to make efforts to ascend. But however great
is the pressure undergone, this acceleration of the respiratory move-
ments never goes as far as panting (P. 21.)
Let us turn to the circulation:
In diving suits, only inexact observations can be made in this
regard; the pulse is very hard to take and there is no way of meas-
uring exactly the time occupied in the observation. Nevertheless I
tried to find the rhythm of my circulation, and I think that its rate
never dropped.
We may say, without trying to explain it, that in compressed air,
at pressures used by sponge divers, the circulatory rhythm does not
seem altered.
This is not true of the amplitude of the pulsations; in this all
experimenters, except Junod alone, agree. They all admit that in
compressed air the pulse becomes filiform and sometimes impercep-
tible ....
Diving Bells and Suits 397
Evidently the superficial capillaries and the arteries which are
nearest the skin are more subject to the effect of the outer pressure
and their caliber lessens. If one goes into compressed air with a
part of the mucous membrane or the outer tegument congested, the
congestion quickly disappears. In the diving suit, in spite of rubber
rings which clasp the wrists tightly, the hands are pallid. But al-
though the quantity of blood in the periphery is diminished, the
organs which by their position are less directly subjected to the action
of the compressed air have a more abundant circulation. Since the
lungs - are under the same conditions as the skin, they must receive
less blood than in the normal state. (P. 22-23)
If one returns from a higher pressure to normal pressure, the
pulse rate accelerates, the pulse which was filiform regains its full-
ness, and if the difference in pressures was considerable, slight hem-
orrhages are sometimes observed.
The agreement of authors on this question is perfect. We were
not able to follow the changes in the circulation during the act of
decompression, but we noted by a great number of observations that
at the moment of reaching the deck the pulse rate of the divers was
almost always more than 80 per minute. Out of 240 observations we
found it to be:
Below 80 heartbeats 11 times
From 80 to 90 heartbeats 103 times
From 90 to 100 heartbeats 124 times
From 100 to 109 heartbeats 2 times
Half an hour afterwards, 203 times the pulse had returned to
nearly normal; 3 times it had fallen definitely below, and 34 tirnes it
was still between 75 and 80.
Here, as in regard to respiration, we cannot attribute the accel-
eration of the rhythm to the act of ascent. As we have said, mus-
cular fatigue is almost absent because of the expansion of the air in
the suit and the slowness with which the diver ascends. (P. 24.)
The secretions furnish him with the following observations:
All authors, except MM. Foley and Frangois, note a greater secre-
tion of urine; I think that this opinion is correct. The divers whom
I have observed could not remain more than an hour and a half sub-
jected to a pressure of 20 meters of water without feeling the need
of urinating; sometimes they even urinated in their suits. The increase
of the salivary secretion was noted only by MM. Eugene Bertin and
Junod; as for me, I cannot form an opinion on this matter; in all the
French divers and in myself the salivary secretion was more abund-
ant than in the normal state; but the presence in the mouth of a rubber
apparatus intended to admit air accounts satisfactorily for this phe-
nomenon.
After this series of purely physiological observations, M. Gal
reaches the study of dangers of high pressures. He divides the
diseases which one may attribute to the effect of compressed air
398 Historical
into two categories: diseases which begin suddenly, which never
occur while the diver is in the compressed air, and which are the
result of the decompression; and diseases with an insidious begin-
ning, which must be directly connected with the action of the
compressed air.
Diseases with a sudden beginning. In the first rank M. Gal
places the "fleas":
This disorder disappears without any treatment and ends when a
hypersecretion of perspiration occurs. (Foley, p. 33) Is it then because
our divers were always covered with sweat when they reached the
deck that I have never had the opportunity to observe it? That seems
to me more than probable. (P. 33.)
Then come the muscular pains, the attacks of arthritis:
Among all these disorders, I have seen only extremely acute pains
appearing suddenly, soon after the exit from the compressed air;
affecting particularly the parts of the body in which muscular effort
was longest exerted, generally the left deltoid in divers; almost always
a little swelling in the part affected, but with no redness. These pains
never lasted more than two days, and generally they disappeared
after a few hours.
All the divers, except two named Thepot and Paugarn, expe-
rienced them repeatedly.
I have not listed any observations on this subject, because these
disorders, which were always slight, showed me nothing abnormal,
either in their course or in their ending. Rubbing with soothing balm
or application of a poultice with laudanum always dispelled them.
Then pains and inflammation of the ears, of which M. Gal
mentions some examples, and gastric disturbances, the cause of
which lies perhaps in the nervous centers. A case of hemorrhage
was observed, which offers this rare circumstance of having begun
during the compression:
December 15, a man by the name of Feroc, 28 years old, a diver
trained to the use of the suit, went down to a depth of 14 to 15 meters,
stayed at the bottom three quarters of an hour and came up with a
nosebleed which began while he was subjected to the pressure. His
face was slightly flushed, his pulse was 70. He told me that it was the
third noseblood he had had, and that it always began on the bottom.
Like the former ones, it stopped without treatment.
January 12, this same diver went down again for the first time
since December 15, to a depth of 20 meters. Another hemorrhage
under the same conditions; only the pulse was 90 a quarter of an
hour after he came up, and an hour afterwards it was 70, weak and
easily depressed. At the same time, an acute headache.
Stimulating friction; rest. The next day he was quite well. (P. 41)
In regard to serious symptoms, M. Gal observed only one para-
Diving Bells and Suits 399
plegia, which, strangely enough, began only twenty-four hours
after the decompression. Here is the complete observation:
Quidelleur, 28 years old, given to drink. January 18, 1869, descent
to a depth of 28 meters.
After staying on the bottom for an hour, he came up deaf in
one ear; it was his first symptom, he had no pain, and merely noticed
a buzzing, accompanied by deafness in the left ear.
January 19, he went to a depth of 16 meters, finished his shift
of an hour and a half, and told me when he came up that his deafness
disappeared at the bottom.
January 20, he went down to a depth of 28 meters. That day,
while four divers were in the sea, and among them Quidelleur, the
ship made a complete turn around its anchor, and this accident
resulted in rolling around the ship's chain the four air tubes and the
four signal cords of the divers.
There was a moment of confusion, during which the signals could
no longer be felt; and when Quidelleur reached the deck, he com-
plained that at three different times he was raised from the bottom
to a depth of about 10 meters, and each time he fell back suddenly,
with great injury to his ears. In all, he remained for one hour at an
actual pressure of 3.8 atmospheres; and he complained only of pains
in his ears, especially the left one.
I had him rubbed with dry flannel, as was always done after a
descent of more than 20 meters, and I noticed nothing abnormal
about him.
On January 21, diving was interrupted all day, and Quidelleur
like the other sailors worked at different jobs on board. In the evening
at 5 o'clock, he came to take me on shore, and I noticed that he did
not look well; when I inquired about it, he assured me that he had
no pain except a little in his left ear. One hour afterwards, I was
sent for; he was complaining of violent pains, without a definite loca-
tion, extending over his whole body. I had great difficulty in making
him talk, but his attitude showed me that the chief pain was in the
abdomen. The patient was doubled over, all his members were bent
against the front of his body. The pains were so great as to make
him weep; he finally told me that the pain was as great as if some-
one were tearing open his belly and his chest. I noted no swelling
and no redness of the skin. His pulse was 70; it was greatly depres-
sed. The rather hasty respiration was jerky ....
At eleven o'clock in the morning (January 22), I was told that
the patient was complaining again of not being able to urinate; I
noted the presence of liquid in the bladder, and warned by this
symptom, I tested for a lessening of sensitivity and motility. Both
were weak in the lower limbs, without being entirely gone. The penis
was in a semi-erection. The introduction of a catheter into the bladder
gave a half-liter of urine. It flowed slowly; muscular contraction was
not present; the bladder was paralyzed. The pulse was quite normal,
the pains of the day before were gone, the respiration was good.
Friction on the spinal column and on the lower limbs with
opodeldoc balm. Elder tea.
400 Historical
January 23. The patient, less stiff, tried to rise, but his legs could
not support him, although when he was in the hammock, he could
move them as on the day before; lessened sensitivity.
Pulse 70, easily depressed. Respiration normal, no pains; the
hearing which on the day before was rather weak on the left, had
returned to normal.
I had plasters put on the lower limbs and along the spinal column.
Elder tea. Catheterisms in the morning. Soup.
In the evening, the paralysis had gone; the patient urinated easily.
Nothing new in his condition; he had not defecated since the day of
the accident, that is, January 20.
January 24. Legs in the same condition; pulse and respiration
normal. No movement of the bowels. The patient wished to eat ....
January 27. Slight improvement, movements of the lower limbs
a little easier, although there was not much strength ....
From that day to January 30, the improvement progressed very
slowly; then suddenly, February 1, the patient came up on deck and
one could hardly tell by his gait that his lower limbs were paralyzed.
During the following days, the improvement was maintained; the
rectum alone was still paralyzed. There were no results unless enemas
were used.
The patient was very intractable as long as his illness lasted; I
could testify that he was of a very weak character, and that he was
easily prostrated by pain.
I wanted to purge him the very first day; but in spite of all my
persuasion, he would not consent.
Up to February 5, he did not defecate and suffered greatly from
his constipation. I administered to him, without his knowing it, 80
centigrams of calomel in some milk; this purge brought on an
evacuation which was the signal for his complete recovery. From
that day, the rectum resumed its normal functions, and the health of
this diver was excellent.
M. Gal gives three more observations of the same sort, the
details of which he gathered himself, although he did not see the
patients at the time of the accident. In the first case, death occur-
red as a result of the doctor's ignorance:
August 5, 1869, a man named Nicolas Theodoros was seized by
paralysis of the lower limbs.
This diver had been fishing on the shores of Crete since the
beginning of May, that is, for three months. He was a man of great
height and at the same time of an enormous corpulence, due chiefly
to the very considerable development of adipose tissue.
August 5, he was fishing near Sitia, and for a week he had been
working in depths of twenty fathoms and more, that is, 30 to 35
meters. No serious symptom, no pain, gave him any warning, when
August 5, a quarter of an hour after coming up from a depth of 37
meters, he was seized by complete paralysis of the lower limbs.
I learned from the Greeks who were diving from the same boat
that he had remained on the bottom more than a half-hour, that he
Diving Bells and Suits 401
had been hoisted up, according to the bad habit of the Greeks, and
that consequently the decompression had been very rapid.
He had taken off his diving clothes and was going to rest on the
deck of his caique, when the illness began gradually by general dis-
comfort, and soon he perceived that he could no longer move his legs,
and that they were completely without sensation.
Unfortunately, at that time I was in Kanea, that is, more than a
hundred miles from the place where this unhappy diver was. His
boat went to the nearest point where they hoped to get help; that was
at Sitia. There was there only an Italian physician completely ignor-
ant of the symptoms which may appear in divers.
Finding no fever and no pain, he did not know what could be the
cause of the illness and remained completely inactive. The death
certificate which he gave to the comrades of the diver simply said
that he died: From intestinal strangulation and constipation.
Although these words indicate that he had recognized the inabil-
ity of the diver to urinate and defecate, he did not heed the first
indication, did not catheterize the patient, and merely gave him a
cathartic; he did not even do that until the eighth day of the illness,
the day before he died.
To the paralysis, which had been painless at the beginning, soon
were added the ordinary symptoms of paralysis of the bladder and
the rectum, when the former is not emptied and the bowels are not
kept open.
When I reached Sitia, August 16, the patient had been dead for
two days, after terrible sufferings located in the abdomen and accom-
panied by a considerable increase in the volume of that part of the
body. The information given me by his comrades was quite recent,
and I am convinced that Theodoros succumbed to the paraplegia only
from want of care. It will be seen by the observations which I shall
give that when the paralysis reaches only the lower limbs, cure is
quite frequent, or at least if the paralysis persists, the patients do
not die, or at least die only after several months. (P. 48.)
In the other two cases, the paraplegia was half cured:
At Symi I saw two divers, Foti Kazi Foti and Yanni, who, during
the cruise of 1867, were both completely paralyzed in the lower part of
their bodies. Both of them returned immediately to Symi, where they
were attended by a doctor who had had his medical course at Paris,
M. Migliorati. I had an opportunity to talk with him; unfortunately,
he was very ill, in the last stages of pulmonary tuberculosis, and he
could give me only a little information.
The two divers remained three months without being able to use
their lower limbs; little by little, however, it became possible for them
to make some movements; the paralysis of the bladder and the rectum
disappeared first. M. Migliorati exhausted all the resources of thera-
peutics on them: friction, blisters, cupping-glasses with scarification,
tincture of nux vomica rubbed in or given internally, etc. However,
he did not try cauterization or faradization:
When I saw them, I noted that the paralytic lesion of the lower
402 Historical
limbs still persisted; they had been ill for more than a year. However
they were able to walk, provided that they used two sticks, but they
did not need crutches. It was evident that it was difficult to them to
lift their feet, and they did so only as much as was absolutely
necessary.
I tested the sensitivity and found a marked weakening on both
sides of tactile sensitivity, sensitivity to heat and cold, and sensitivity
to pain.
All the other mechanisms and all the other functions were normal.
I observed, however, a little anemia in Yanni, but it had no connection
with the paralysis; in 1868, he had had obstinate intermittent fevers,
from which he had recovered only a short time before I saw him.
The muscles of the lower limbs were not manifestly atrophied.
These two men continued to use the diving suit. They resumed their
work, one in the month of October, 1868, the other in the month of
May, 1869, and they found that walking was easier in the water than
in the open air.
In the month of January, 1870, their condition was unchanged.
(P. 50.)
Next comes a series of 9 observations, in which 2 divers died
very quickly, one after twenty-four hours, the other after three
months, from the sequelae of paraplegia. The last five recovered
more or less completely. I reproduce in full these observations,
which are very brief:
I. June 23, 1868, at Navarin, Jorgieos Koutchouraki, who had gone
down to a depth of 40 to 45 meters, remained on the bottom for a
quarter of an hour. According to the custom of Greek divers, he had
himself hoisted up after this time; he reached the deck of the boat in
perfect health; a few minutes afterwards, he complained of dizziness,
and fell upon the deck. Loss of speech and intelligence; face red;
sudden death.
II. July 10, 1868, in the Greek Archipelago, Manolis Couloumaris,
went down to a depth of 25 fathoms, that is, about 40 meters, and
remained on the bottom about three-quarters of an hour. He then
gave the signal agreed upon and was hoisted up. He had been on deck
about a quarter of an hour, and, according to his comrades, he was
squeezing out the sponges which he had brought up, when he was
suddenly attacked by severe pains, and almost immediately by com-
plete loss of consciousness. He rapidly succumbed.
III. June 15, 1869, on the coast of Bengasi, a man by the name of
Joannis Xippas went down 20 fathoms, that is, 30 to 35 meters. This
diver had gone down five days in succession, and several times each
day, in depths always more than 30 meters, and until that time had felt
no symptoms, except a little pain in his left arm. June 15, he had
gone down for the second time when the attack came. Coming up
after a stay of more than a half-hour, at first he did not seem ill,
and went down to the deck of his caique to rest. Only an hour after-
wards one of his comrades, going down to him, found him uncon-
Diving Bells and Suits 403
scious, his face red, his limbs completely inert and covered with cold
sweat. They tried to warm him, but could not succeed.
They set sail for Alexandria, where they hoped to find help;
but death came after 24 hours. The patient had remained all this
time absolutely motionless. He had not defecated or urinated. Those
present at his death stated that shortly before he died, he gave certain
signs of consciousness and pain; but the paralysis of his limbs re-
mained complete.
IV. July 1, 1869, on the coast of Rhodes, a man named Nicolas
Roditis, who had been diving in a suit for about three months, came
up from a depth of 35 to 40 meters. After a half-hour, he was seized
by severe pains in the epigastric region, and at the same time per-
ceived that he could no longer stand up. They took him to Rhodes,
where he first consulted a quack, who had him put in an oven. He
was not relieved, as one may well imagine; the pains in his stomach
persisted; the paralysis of the lower part of his body was complete,
and affected the legs, thighs, bladder, and rectum. To the pains of
the epigastric region was added the tension of the belly; for three days
he had not urinated or defecated, and then an Italian physician was
summoned, who catheterized him at once and then tried to cure his
paraplegia. They gave him various remedies and had him rubbed;
but it was impossible to find out exactly what treatment was given
him.
One month after the accident, he came to Calymnos, where Dr.
Pelicanos attended him. At that time, he was completely paralyzed
in the whole lower half of his body, both in motility and sensitivity.
The bladder and the rectum shared in this paralysis.
Moreover, he had on the back and lower part of the trunk a large
sore 14 by 15 centimeters. All the soft parts were ulcerated and the
sacrum was bared. At the level of the two great trochanters, there
were also two sores; one had destroyed the skin; in the other, the
bone was -bared. Scab on the right calcaneum. Scab on the lower and
outer part of the fifth left metatarsal and on the sole of the same
foot. Excruciating pains in the region of the stomach; persistent con-
stipation. The patient was very anemic.
He was first given syrup of lactate of iron, cinchona bark, old
wine of Cyprus, and a diet as nourishing as possible. The sores were
washed with a decoction of camomile and cinchona; they were dressed
with aromatic wine. From time to time a cathartic with castor oil
or jalap powder.
No improvement; the sores grew larger; a fever of the daily inter-
mittent type, growing worse every evening, appeared. It was evi-
dently hectic fever.
Appetite was almost wanting, the general condition grew worse;
a gangrenous sore spread over the prepuce, and finally the patient
succumbed in marasmus three months after his accident.
The paralysis of the bladder had disappeared one month before;
but there had been no improvement in the motility and sensitivity
of the lower limbs.
V. In the early part of September, 1868, a man named Nicolas
Kardachi, on the coast of Bengazi, was seized by paralysis of the
404 Historical
lower limbs, the bladder, and the rectum. He showed complete paral-
ysis of movement, hyperesthesia of the skin, and severe pains from
the region of the kidneys to the ends of the toes.
The disturbance had appeared very shortly after he had come up
to the deck of his caique.
He was taken as quickly as possible to Calymnos, where he arrived
five days after the beginning of his illness. He had not urinated or
defecated; the bladder, which was much distended, caused him acute
pain. Catheterization, the use of cathartics, and the application of a
large blister to the spine in the region of the loins were the first
measures used by Dr. Pelicanos.
The patient was wholly free from fever; his appetite was good;
the regimen was tonic from the first.
The blister in the lumbar region was renewed, and motility re-
turned little by little, at the same time as normal sensitivity. The
paralysis of the bladder was the first to yield, and after a month and
a half the patient could walk a little, dragging his feet. First he was
given frictions along the spinal column with tincture of nux vomica,
and then with the following liniment:
Olive oil 250 grams
Essence of turpentine 30 grams
Camphor 4 grams
Tincture of cantharides 4 grams
Liquid ammonia 20 grams
Dr. Pelicanos is well satisfied with the use of this last remedy;
motility returned little by little, and at the end of three months the
patient was perfectly cured.
VI. September, 1868. The history of this patient, named Nomikas
Sissois, is exactly the same as that of the preceding one. Like him, he
was attacked while fishing at Bengazi, at the end of the fishing season,
in depths of 35 to 45 meters; he was slower in going to Calymnos,
and the disease lasted longer, although he could walk, dragging him-
self about, at the end of a month.
The treatment was the same, the duration of the disease six
months; and in January, 1870, that is, fifteen months after the begin-
ning, there was only a slight hesitation in his gait. They tried with
him an injection into the bladder of a dilute solution of sulphate of
strychnine; but this measure did not give satisfactory results.
VII. In the month of August, 1869, on the coast of Crete, a man
named Philippe Karantoni was paralyzed in his lower limbs after
diving to a depth of 35 to 40 meters. The bladder and the rectum were
not affected. They used as treatment only the stimulating liniment
already indicated, and he was cured in two weeks.
VIII. In the month of September, 1869, in the Greek Archipelago,
a man named Georges Ervloia was paralyzed in the whole lower part
of his body; the bladder and the rectum were affected; the patient
also had violent pains all through his body. He reached Calymnos
the day after the beginning of his illness.
Catheterization, a cathartic, and the use of the stimulating lini-
ment brought a complete cure in twenty days.
Diving Bells and Suits 405
IX. In the month of September, 1869, a man named Georgios
Baboris was diving at Candia; he was slightly affected by paralysis.
Treated at Megalo-Castro, he was very soon on his feet and only a
slight weakness of his lower limbs remained.
After this interesting enumeration, M. Gal adds:
What we have just shown by these observations, the frequency of
functional lesions of the spinal cord, appeared also in the ten divers
who died in 1867. Only three died suddenly; the other seven dragged
on a longer or shorter time. The latter were all paraplegic. I had
another purpose in listing these observations, that is, to show tiiat
with precautions one can lessen the number of accidents considerably.
So in 1867, there were in Greece 12 diving suits manned by 24
divers; there were ten deaths. The Greeks went down to depths of
more than 45 meters, had themselves hoisted up rapidly when they
wished to come up, and made a considerable number of dives during
the day.
In 1868, there were at least ten suits at Calymnos alone. They
used 30 divers; there were two deaths, and two cases of paraplegia
ending in recovery.
In 1869, more than 15 suits, using more than 45 divers. Three
deaths and three cases of paraplegia.
I could get these statistics only for the island of Calymnos; but
one can see how much the number and the severity of the accidents
diminished. The precaution of taking three divers for each suit, to
lessen the daily work of each one, and a little greater care in regard
to the depth were enough to bring about this result. A little book
published in Greek by M. Denayrouze and distributed liberally among
the divers has no doubt had its share in bringing about this improve-
ment. (P. 56.)
And now we come to the second category of diseases obser-
ved among the divers. M. Gal calls them by the name of Diseases
with gradual beginning; according to him, they are the multiple
manifestations (emaciation, loss of strength) of a peculiar anemia:
Like Foley, we attribute the emaciation to the effect of the com-
pressed air and what we have noted many times, that after several
days of work, all the divers without exception showed evident symp-
toms of anemia, and a much more definite susceptibility to attacks of
the diseases with a sudden beginning. It was then that almost all
experienced more or less keen muscular pains, and that prudence
required us to make them take a restorative rest. (P. 57.)
I owe to Dr. Sampadarios of Egina a series of interesting and
unpublished observations which I copy without omitting anything;
I am glad to be able to thank him here for his interesting com-
munications:
Observation I. During the summer of 1866, they called me to
attend one L. This man had for some time been diving in a suit in
406 Historical
sponge fishing; he was forty years old. The day before, after he had
come up from the bottom, he had fallen into a state of coma; when I
saw him, he was in his last moments, his face puffed up and bluish,
as if he were dying of asphyxia.
Observation II. In 1867, I observed another patient; he had gone
down three times in one day to fish, he said; the third time, he had
felt an oppression in his chest at the bottom of the sea, and he had
hardly had time to give the signal to be raised. When he was in the
boat, he had fallen into a state of coma, quite insensible, from which
he had recovered after three hours. He then had dyspnea, complete
paralysis of the lower limbs and the bladder, constipation, incomplete
paralysis (paresis) of the upper limbs, on one side especially. The
dyspnea had soon disappeared; they were forced to empty the bladder
with a catheter. The progress of the patient had been followed for a
month, there was an improvement, then they lost sight of him.
Observation III. N. B., attended by another colleague; for some
months he had had a paralysis of the lower limbs and the bladder,
with constipation; the urine was always drawn with a catheter. There
was only a slight flexion of the coxofemoral articulation and that of
the knee; more or less advanced paralysis of sensitivity. When the
patient had been drawn up from the bottom, he remained for several
hours in a state of coma; when he had recovered from this, he had
dyspnea and his members were paralyzed.
Observation IV. N. A., a sturdy young man, aged 25, in good
health till now; for some time he had been connected with a company
of sponge fishermen, and he was diving in a suit. I had been sum-
moned to attend him July 20, 1870, and he told me that two days
before, he had worked too long, because he had stayed, he said, for
five hours on the bottom, collecting sponges, and consequently he had
had a sort of fainting fit. However he had gone down again to work;
but after working a half -hour, he felt ill, gave the signal to be drawn
up, and was pulled up very quickly, as usual, when there is a sign
of danger; the diving suit was also taken off him very quickly, and
after that, he fell into a state of insensibility. He had felt a numbness
of the limbs and dizziness, and his mouth foamed, he said. They had
not called a doctor, because the divers had had such symptoms several
times, and had recovered after several hours through the use of
frictions and revulsives on the extremities. He too had recovered
from this comatose state after five hours, after he had vomited several
times; but for twenty-four hours he was dizzy whenever he opened
his eyes; the lower limbs and the bladder were paralyzed. At the
beginning there was also a sort of paresis of the upper limbs, which
quickly disappeared, but the complete retention of the urine persisted,
and that is why they called me on the third day.
I found the bladder rising as far as the navel; there was consti-
pation and the lower limbs were paralyzed; on the right side there
was complete paralysis of movement and sensitivity; on the left, sensi-
tivity was partly present with weak flexion of the coxofemoral
articulation; there was no other disturbance, no pain in the spinal
column. We emptied the bladder with the catheter; the next day a
purge with castor oil gave evacuations. We continued to catheterize the
Diving Bells and Suits 407
patient; finally, after twenty-one days, the patient could urinate with-
out assistance. We should note that after the eighth catheterism a
very severe attack of intermittent fever came on, for which we gave
quinine, and which did not recur.
The paralysis of the limbs yielded also to stimulating frictions,
and on the fortieth day the patient could walk with crutches. We gave
him extract of nux vomica, pains appeared along the limbs, but no
improvement resulted. Not knowing the nature of the illness, we
gave a symptomatic treatment; we gave iodide of potassium intern-
ally.
October 24. The lower limbs were still weak, especially on the
left, where we noted at the same time, in the leg and the foot, lack
of sensitivity to pain and touch, and a moderate sensation of cold.
On the right, where at the beginning there was complete paralysis of
sensation and movement, the insensibility persisted only on the outer
part of the back of the foot. The active movements were carried out
well, except a weakness on the left at the tibio-tarsal articulation,
especially in flexion. The passive movements were natural.
Examination by electricity (induction apparatus) found at the
right the electrical contractility lessened in the muscles which depend
upon the peroneal nerve. On the left, not only these, but also the
tibial muscles showed lessened electrical contractility. The other
muscles reacted well, like those of the belly.
We continued to faradize the skin and the muscles of the limbs
and the belly. There was an improvement. For two hours after the
faradization the patient felt that his movements were free, as if he
were quite well.
November 28. Lack of sensitivity to pain, touch and cold on the
left halfway along the thigh, even half of the penis, on the right only
lack of sensitivity to pain and touch on the foot; weakness of the
limbs, however, extension of the foot on the right was very incom-
plete. If the patient closed his eyes, he tottered and began to fall.
Lack of coordination or irregularity of movements during walking,
involuntary, convulsive contractions, through reflex action of the
lower limbs, for example, from the bite of a flea on the buttocks or
the loins. Sometimes retention of the urine, at other times, incontin-
ence. We applied two cauteries on the spinal column, and gave him
internally iodide of potassium.
December 10. Improvement, he wants to go away.
After my publications on this subject, in 1871, in the month of
September, Dr. Cotsonopoulos, of Nauplia in Morea, published an
observation, followed by an autopsy in the Greek Journal Asclepios
(Esculapius), in which my observations are also published. I will
make a translation of it for you.
D. N, aged 30, a sailor in good health, strong, who had been
working for a year with the English diving suit, was taken to the
hospital of Nauplia on May 2. Six days before he had been working
on the shore of the Argolic gulf, at a depth of 30 meters on a muddy
bottom. When he was drawn up, he felt a pain in the loins and great
numbness in the lower limbs, movement of which after an hour was
wholly impossible. His companions rubbed him and cauterized his penis.
408 Historical
A physician bled him before he entered the hospital and several
times placed on his loins cupping-glasses, a blister sprinkled with
strychnine, and cauteries with the cautery already there. When he
entered the hospital, the paraplegia was complete; no movement of
the lower limbs; no contraction even by electricity, they said; loss of
sensitivity, even electrical sensitivity. The upper third of the thigh a
little sensitive; the patient sometimes had spontaneously a burning
sensation in the legs; paralysis of the bladder, sluggishness of the ali-
mentary canal, the belly swollen: the bladder was emptied twice a
day. Pressure on the spinal column was not painful. A painful
erythema existed in the sacral region, that was the beginning of the
gangrene of decubitus, which developed later. No fever. In the pres-
ence of such symptoms which came on suddenly with pain in fne
loins, a hemorrhage in the spinal column was assumed, and orders
were given again for cupping-glasses and leeches on the anus, cath-
artics, and vinegar enemas, since the cathartics were not effective.
There was a slight improvement: sensitivity increased a little on the
upper part of the thighs, but soon the disease made progress; a
cystitis developed with gangrene of decubitus, fever, chills, incon-
tinence with retention, involuntary evacuations; finally, on account of
the progress of the gangrene, the sacrum was wholly bared. During
the last days of the sickness sores appeared on the heels.
Death occurred on the fortieth day from the beginning of the
sickness. The patient had preserved his mental faculties intact up to
the end.
Autopsy. There was some difficulty in getting the permission of
the relatives for the autopsy. Dr. Jeanopoulos was present. The dorsal
canal was opened and blood was found in quantity, half-coagulated,
reddish-black, between the dura mater and the canal of the bone and
extending from the first lumbar vertebra to the end of the meningeal
sac. The outer surface of the dura mater, which was wet with blood,
was reddish black and infiltrated with extravasated blood. Its inner
surface after being sectioned was found to be whitish and slightly
bloodshot. In the lower part of the subarachnoid cavity there also
existed an effusion of dark red blood, half-coagulated in a fairly large
quantity around the nerves forming the cauda equina. Having made
incisions in different parts of the spinal cord, we found that a large
part of the lumbar portion and the upper third of the thoracic portion
had undergone the white softening to a considerable degree, because
hardly was the pia mater cut or torn when the substance of the
marrow flowed out, so to speak. The other parts of the marrow, even
those which were situated between the softened parts, had the natural
consistency; no congestion in either the marrow or the pia mater.
Since the relatives of the patient had arrived, no examination was
made of the other cavities; only the hypogastrium was opened for
an examination of the bladder, the walls of which were much hyper-
trophied.
Such are the observations published in our country up to the
present concerning this question.
If we analyze these different data, we see that death occurred in
two manners: either immediately or by lesion of the spinal cord.
Diving Bells and Suits 409
When the nature of this disease has been determined, we shall know
whether there are two different causes which produce these two kinds
of morbid manifestations, or whether they are different degrees of
one affection.
I shall merely remark that if one tried to explain these symptoms
solely by the change in the atmospheric pressure, that would not be
enough; because very certainly the disturbance of health began at
the bottom of the sea. The fisherman felt ill and gave the signal to
be hauled up. M. Cotsonopoulos mentions a case in which the diver
was hauled up almost dead, and died after a few movements. The
patient whom I attended also told me of a similar accident. I am
not sure whether death came to my patient in the same way (obser-
vation I). These people say that they are sick when they work at a
great depth for four or five hours, when there are wind and waves
(and perhaps the pressure of the machine cannot be regulated then),
and finally when they are too tired. It must be noted that when the
diver gives the signal that he is ill, haste is made to draw him up
very quickly, and to the first disturbance perhaps that of sudden
decompression is added. When they go down to a depth greater than
30 meters, they cannot work there very long; the deeper they go, the
shorter a time do they remain. Moreover, sometimes the pressure of
the machine is not strong or regular enough, and the diver feels the
column of water beginning to press the suit around his hands and
feet; then he makes the signal agreed upon and air is sent him. It
seems that they were working in our country, at least at first, with
the English suit.
As for the persistent paraplegia, we see that it is a remnant of
a disturbance which acted upon the whole organism (observations 2,
4), but which, not having caused death, leaves material disturbance
only in the spinal cord, because we cannot accept the idea that this
affection of the marrow alone caused death or that general state
observed at the beginning. But what is the nature of this affection?
M. Le Roy de Mericourt thinks that capillary hemorrhages occur in
the spinal cord during the deebmpression. In our patient, (observation
4), we saw at the beginning a paraplegia, a complete failure of the
functions of the spinal cord; a very great improvement occurred after
a few days, and later we had the syndrome of myelitis. The seat of
the affection must be in the thoracic portion, since the bladder and
the rectum were more or less paralyzed, for when the lumbar region
is affected, there is merely paralysis of the lower extremities.
The autopsy of the other patient showed us diffused softening of
the spinal cord and a hemorrhage. But it is the softening of
the cord, which did indeed affect the thoracic portion, which can
explain the symptoms of paralysis of the bladder and the rectum,
and not the hemorrhage which affected the lumbar portion. As for us,
we think that the ecchymoses of the membranes are related to the
gangrene of the sacrum. Let us say in addition that our patient had
felt no pain, and pain would have been produced in case of hemorr-
hage of the membranes of the cord.
But how is this inflammation of the cord produced? Is it by cap-
410 Historical
illary hemorrhages? Is it by expansion of the capillaries by gases
and, as a consequence, by faulty metabolism (softening)?
Microscopic examinations in men and animals may settle this
question.
Samsoun (Turkey in Asia), June 6, 1875.
- 1 quote this opinion of Panthot frcm Brize-Fradin, p. 31.
3 La Chimie pncumatique apptiquee aux travaux sous I'eau Paris, 1SOS _
4 Lettre au professeur Pictct sur la clothe du plongeur. Btbl. univ. de Geneve, Vol. Alii.
j 230-234 1820
5 Relation d'nne descentc en mer dans la cloche du plongeur. Paris, 1826.
6 Triger, Memoir e sur un appareil a air comprime, pour le percement des pints de mine
et autrcs travaux, sons les caux et dans les sables submerges: Compt. rendus Acad, des sciences.
■'Rapport sur' les puhs a air comprime de M. Triger. Bull, de la Soc. indust. d' Angers et
du depart, de Maine-et-Loire, 1845.
8 Lettre a M. Arago. Comptes rendus de I' Academic des sciences, Vol. XX, p. 445-44y; IMS.
9 Memoir e sur V extraction des roches de la passe d'entree du port du Croisic. Ann. des
ponts et chaussees, 184S, First semester, p. 261-315.
10 Rapport sur le precede suivi, a Douchy, pour traverser des nappes d eau considerables.
Ann. des mines, Fourth series, Vol. IX, p. 349-364; 1846. ,
u Mcmoirc sur les effets de la compression de 'air apphquee au creusement des pints a
houille. Ann. d' hygiene publique et de medicine legale. Second series, Vol. I, p, 241-279: 18o4.
Memoir written at the end of the year 1S47, and presented to the Societe de Douchy shortly
12 Rapport sur V explosion d'un cylindre a air comprime sur I'avaleresse No. 7, situee dans
la concession de Douchy (Nord). Ann. des mines, Fourth series, Vol. II, p. 121-148, 1847. _
13 Creusement a travers les sables motivants d'un puits de la mine de Strepy-bracquegnies.
Ann. des trav. publ. de Belgique, Vol. VII, 1848; quoted by Barella, p. 621
14 Lettre a M. Arago. Comptes rendus de V Academic des sciences, Vol. XX, p. 445. 1S4&.
^Notice sur le pont de la Theiss et sur les fondatiens tubulaircs. Annales des ponts et
chaussees, 1859, First semester, p. 334-3S2.
16 Memoire sur la construction du pont metallique sur la Garonne, a Bordeaux. Ann. aes
ponts et chaussees, 1867, Second semester, p. 27-145.
17 One atmosphere corresponds to 15 pounds per square inch.
15 Paralysis caused bv working under compressed air in sinking the Foundations of London-
derry New Bridge. The Dublin quart, journal of medical science, Vol. XXXVI, p. 312-318, 1SG3.
19 Des effets de I'air comprime sur les ouvriers travaillant dans les caissons servant de base
auv piles du pont du grand Rhin. Ann. d'hyg. publ. et de med. leg., 1860, Second series, Vol.
XIV, p. 289-319. . , , „ ., , c, „
20 Remarques sur I'emploi de Van comprime dans les travaux dart. Gaz. med. de Stras-
bourg, 1860, p. 179.
21 De I'air comprime. These de Strasbourg, 1861.
22 Du travail dans I'air comprime. Paris, 1863.
23 Memoire sur I'etablisscment des travaux dans les terrains vaseux de Bretagne. Ann. des
Ponts et Chaussees, 1864. First semester, p. 275-396. ;
24 Symptoms produced by the use of caissons in underground and undersea works. Art
Medical, Vol. XVI, p. 428-452, 1862; Vol. XVII, p. 27-48. 105-124, and 194-213. 1863
23 Action de I'air compnmes apoplexie de la moelle epimcrc. Union medicate de la Uironde.
1863, p. 269-270. ,,. - vv
26 Soc. des Sc phys, et nat. de Bordeaux, year 1874-1875. Minutes of the sessions, p. XX.
27 Weighing nearly 500 kil., says the report of the engineer Dubreil.
™ Ann. des Ponts et Chaussees, 1867, Second semester, p. 116-131. .
29 Du travail dans I'air comprime. Observations recueillies a Trazcgnies. lors de I enfonce-
ment d'un nouveau puits houiller. Bull. acad. de med. de Belgique, Third series, Vol. II, p.
3» The' effects of compressed air on the human body. The Med. Times and Gazette, Vol. II.
31 Pathological effects upon the brain and spinal cord of men exposed to the action of a
largely increased atmospheric pressure. St. Louis Med. and Surg, journ.. May, 18.0. Extract
in Canstatt's Tahr., Vol. I, p. 178. 1870. .
32Travai:v publics des Etats-l'nis d'Amcrique en 1.^73. 1 avis, is,.).
33 Fondations a I'air comprime. Ann. des Ponts et Chaussees, 1S74. First semester, p. 329-
402
34 Considerations sur I'hygiene des pecheurs d'eponges- Ann. d'hygiene publique et de
medecine legale, Second series. Vol. XXXI, p. 274-'2>6. 1><1!>.
35 Des dangers du travail dans I'air comprime et des moyens de les preventr. theses de
Montpellier, 1872.
Chapter II
LOW PRESSURES
The pressures discussed in this chapter have never reached
one atmosphere above normal pressure. Workmen employed on
the foundations of bridge piers, and divers in suits are evidently
also subjected frequently to these moderate pressures; but since
they do not experience any distress there (except pains in the ears
at the beginning) and since they come from them with no ill effects,
the attention of engineers or physicians has almost never been at-
tracted to the phenomena which they might have observed under
these conditions.
The case is quite different for the low pressures which physi-
cians use frequently today for therapeutic purposes. Here, on the
contrary, delicate observations, of a purely physiological order,
have been accumulated, and a study has been made of the effect
of slightly compressed air with the same care and following the
same method as that of any medicinal substance: that is, on man
in good health at first, then in different pathological cases.
To three French physicians, Junod of Paris, Tabarie of Mont-
pellier, and Pravaz of Lyons, is due the honor of having introduced
into therapeutics an agent the efficiency of which is noted every
day by practitioners and the use of which will become, we are
safe to state, more and more frequent. I do not wish to take sides
in the quarrel which has arisen among them on the subject of
priority of invention; as far as I can judge, it belongs to M. Junod;
at least it is he who first had publications on this subject.
Today, the apparatuses intended for treatment by compressed
air are fairly numerous. Establishments are now found: in France,
two in Paris, others in Lyons, Montpellier, and Nice; in Germany,
at Hanover, Stuttgart, Wiesbaden, Johannisberg, Reichenhall, and
Ems; in Denmark, at Altona; in Sweden, at Stockholm; in Scot-
411
412
Historical
Fig.
9— The aerotherapeutic establishment of Dr. Carlo Fornanini, at
Milan. Horizontal cylinder containing two chambers; the front
wall of the chamber at the right has been removed.
land, at Ben Rhydding; in England, at London; in Italy, at Milan.
Figure 9 represents the apparatus which Dr. Fornanini has in-
stalled in the last-mentioned city.
The various directors of these establishments have different
opinions as to the pressure which should be used or rather as to
the degree at which they should begin. There are some who ap-
prove of high pressures, 30 centimeters at least; in Paris, M. Leval-
Piquechef prefers to begin very moderately, 10 centimeters at the
most. It is not for me to discuss these different points in practice;
nor shall I give any time to the therapeutic applications of the
method, limiting myself to saying once for all that its efficacy has
been considered very great in emphysematous asthma, chronic
bronchitis, chloro-anemia, and passive hemorrhage; it seems to be
both tonic and sedative, to use the language of the School.1 (of
Medicine)
Before listing the evidence collected by physiologists and phy-
sicians, I think I should report, acccording to Jaeger,2 the account
of a catastrophe which made a great stir at the time, and in which
workmen and physicians maintained that compressed air increased
Medical Apparatuses 413
the sufferings of the victims, a point which is far from being proved,
in my opinion.
February 28, 1812, at 11 o'clock in the morning a gallery of the
coal mine of Beaujeu, near Leodium, was overrun by water; there
were 127 workmen at a depth of 270 meters. Ninety of them were
cut off at the end of a gallery, in compressed air "capable of hold-
ing water at 64 feet in a metallic tube, so that its density was
double that of the atmosphere." They remained in this critical
position for 7 days; only 70 survived:
As it was impossible for these unfortunate men to communicate
with the rest of the gallery, they remained confined in a narrow space,
deprived of air and everything. But their foreman Coffin and his son
showed heroic courage ....
It was not possible to reach them before the seventh day. So,
for seven days and as many nights, they were deprived of light and
food, and exhausted by constant work. They suffered incredibly from
hunger and thirst; respiration was difficult, and the candles went out
for lack of air. They felt suffocating heat; their skin was dry and
burning. They said that the enormous pressure of the air was very
painful to them .... Some became mad, and the others had to aid
them and protect themselves against them ....
In my opinion, the amazing density of the air was the cause of
these phenomena. There is no doubt that the air produced more
heat by its condensation, for, we know, condensation can produce fire
.... And therefore the processes of combustion were so accelerated
in the lungs that the sensation of heat can be explained. (P. 98.)
The first publication relating to symptoms experienced by men
placed in compressed air was made by M. Junod.3 He reports his
observations in the following words:
When we increase by one half the natural pressure of the atmos-
phere on the body of the man placed in the receiver, this is what we
observe:
1. The membrane of the eardrum, pushed back towards the inner
ear, becomes the seat of a rather unpleasant pressure. However, this
sensation disappears as equilibrium is reestablished.
2. The respiratory movements go on with new ease, the capacity
of the lungs for air seems to increase, the aspirations are deep and
less frequent; after 15 minutes, one feels an agreeable warmth within
the thorax, one would say that the pulmonary areolae, which for a
long time had not known contact with the air, are expanding to receive
it again, and the whole system with each inspiration drinks in
increased life and strength.
3. Increase of the density of the air seem to modify the circulation
considerably; the pulse has a tendency to become rapid; it is full and
not easily depressed; the caliber of the superficial venous vessels
414 Historical
lessens and may even be entirely obliterated; so that the blood, on
its return towards the heart, follows the deep veins. If the caliber
of the superficial vessels increases or diminishes because of the tension
of the atmospheric elasticity, the same thing must be true in the pul-
monary organs, which are under the same conditions in this respect;
the inevitable result of this must be that when the pressure of the
air is increased, the quantity of venous blood contained in the lungs
must decrease; no doubt that is why a much greater quantity of air
can be inhaled at each inspiration than at normal atmospheric
pressure.
If the increasing density of the air lessens the caliber of the
venous vessels, the necessary result must be that the blood flows in
greater quantity in the arterial system, and towards the principal
nervous centers, especially in the brain, which is protected from the
direct pressure of the atmosphere by the resistance of the bony case
in which it is contained. So the functions of the brain are activated,
the imagination is lively, thoughts have a peculiar charm, and in some
persons symptoms of intoxication are evident. This increase of inner-
vation acts also upon the muscular system; movements are easier
and more assured.
4. The functions of the alimentary canal are expedited: thirst
is wanting;
5. The salivary and renal glands secrete their fluids abundantly.
(P. 159.)
The report made by Magendie on the work of M. Junod, from
which we quoted earlier (page 229) the part relating to the effect
of decrease in atmospheric pressure, says nothing new on the sub-
ject, about either symptoms or theories.
It was not until 1838 that Tabarie 4 published his researches,
which, he said then, nevertheless dated back to a considerably
earlier period.
His note ^hows that he had planned a series of very complex
problems, since the processes which he had used included:
1. General compression of the air over the whole body;
2. Local compression over the limbs;
3. Local rarefaction over the limbs.
4. Alternate and local compression and rarefaction or oscillation
on the limbs;
5. Rarefaction over the whole body except the head;
6. Use of alternate compressions and rarefactions over the whole
body except the mouth, resulting in an artificial and complete respir-
ation to be used in cases of asphyxia.
The rest of his note contains only a very short summary of
applications of these different methods. It contains nothing definite
either in regard to physiological phenomena or relating to the
theoretical ideas he formed about the action of compressed air.
Medical Apparatuses 415
But in a later work 5 he is a little more explicit in the description
of the phenomena.
The effect of compressed air, he says, is marked by two chief
points:
1. Compressed air acts upon the circulation by slackening it; and
while it lessens the number of heartbeats, it regularizes their rhythm.
These phenomena, which are hardly noticeable in a normal state
of health and under the effect of short or incomplete experiments,
become very marked in case of inflammatory or feverish diseases,
provided that the experimental conditions are properly fulfilled and
sufficiently maintained ....
2. Compressed air does not affect general heat production as air
with higher oxygen content would do; for far from stimulating this
function, as has been supposed through analogy, it moderates it, and
in certain cases even depresses it.
This fact, which I stated with some hesitancy in 1838, has been
proved since then by new evidence. Not only does the use of the
compressed air treatment develop no unusual heat within the thorax,
but, on the contrary, it tends to produce a general sensation of cold,
even when the temperature within the apparatuses is higher than
that outside; and in some subjects in whom this chilly feeling is more
marked, we note that it increases with the length and the degree of
compression of the treatment.
Better results are obtained at moderate pressures (% of an atmos-
phere) than at higher degrees (% of an atmosphere).
However, Tabarie's note contains no theoretical explanation.
The first attempts of Pravaz to apply compressed air treatments
to therapeutics date back to 1836. In 1837,6 he began to publish
the result of his observations. He summarized his previous notes
and memoirs in the work which we are taking as our guide.7
His apparatus measured 9 cubic meters. The pressure used was
generally from 30 cm. to 35cm. Pravaz describes as follows the phe-
nomena displayed by the subjects of his experiments:
In most of the subjects of good constitution and in a healthy
state, the arterial circulation does not show great modifications, no
doubt because the respiration which was sufficient for hematosis under
ordinary pressure keeps about the same rhythm in compressed air;
but this is not true when there is a morbid acceleration of the pulse;
then it drops considerably, except in a few exceptional cases which
will be discussed later.
The congestion of the capillaries of the skin and the mucous
membranes is evidently decreased by the increase in pressure exerted
upon the periphery of the body. This effect becomes very apparent
upon the surface to which a vesicant is applied or the conjunctiva,
when the latter is red and inflamed.
The stimulation of the digestive organs, noted by MM. Colladon
and Junod, is not always limited to producing a simple increase of
416 Historical
appetite; sometimes this stimulation, after a certain time, reaches the
point of causing a real bulimia, which forces one to discontinue or
make less frequent the use of the compressed air treatment.
Among the secretions the increase of which has been mentioned
by the authors whom I have just quoted, that of the urine displays,
in quantity and nature, changes which seemed to me most remarkable;
and that would naturally result from the greater activity brought to
the metabolism of the tissues by a greater absorption of oxygen.
The feeling of easier, deeper respiration is not experienced in the
same degree by all subjects placed in compressed air. Those who
usually breathe deeply hardly notice it, but the same thing is not true
of patients or valetudinarians attacked by a more or less pronounced
dyspnea, either on account of an affection of the thoracic organs, or
on account of a state of venous plethora; in general they experience a
sensation of extraordinary well-being which would persuade them
that they are cured, if it continued after the treatment. (P. 112.)
Another doctor of Lyons, Milliet,8 who had founded the estab-
lishment at Nice, a few years afterwards published observations
which partly agree with those of Pravaz:
One of the most remarkable phenomena produced by increase in
pressure of the air breathed is the considerable slackening of the
circulation caused in most of the subjects. The circulatory rhythm
drops 10, 15, and even 45 heartbeats .... In a woman 74 years old,
suffering from a subacute catarrhal affection, the pulse, which had
risen to 120, fell to 60 and remained there. (P. 13.) ....
In compressed air, the movements of inspiration slacken; they are
repeated with less frequency in a given time to maintain regular
pulmonary nutrition. (P. 15.)
However the new method of treatment had made progress; ap-
paratuses had been installed at Stockholm, by Dr. Sandahl,9 who
in 1862 reported the physiological phenomena which he had
observed.
After indicating, discussing in detail, and explaining the usual
pains in the ears, Sandahl comes to the respiratory and circulatory
phenomena:
In 1454 observations, dealing with 75 persons, the respiratory
movements were slowed in 1362 cases, including 64 persons; in only
11 persons, who took in all 102 treatments, was respiration more rapid
than before ....
In general, we find that the decrease in the number of respiratory
movements not only comes during the treatment, but also lasts after
the treatment ....
The heartbeats also become slower .... So the pulse in the
treatment where the air was compressed a half-atmosphere, dropped
9.94 beats on the average.
Medical Apparatuses 417
Similar observations were made at Nice. Tutschek 10 declares
that the effect of compressed air is shown by:
1. Enlargement of the pulmonary alveoli; 2. decrease of the num-
ber of respirations; 3. slackening of the arterial circulation; 4. accel-
eration of the venous and capillary circulation; 5. stimulation of
organic expenditures and of assimilation, evidenced by greater excre-
tion of carbonic acid and urea, and by hunger reaching the point of
gluttony; 6. greater stimulation of the nervous system by a blood
richer in oxygen, evidenced by activity of mind and a sensation of
lightness of movement.
He does not give the pressure used. Everything leads us to
think, moreover, that this summary of symptoms is merely bor-
rowed from former authors; Tutschek made observations on only 3
healthy persons and 6 sick ones. In the former, the number of
respirations decreased by 3 to 5 and that of the heartbeats by 0 to
10; the changes were greater in the invalids.
In Germany, Dr. G. Lange, physician at the spa of Johannisberg,
had installed in this establishment an apparatus for the use of com-
pressed air. In collaboration with Rudolph von Vivenot, he there
made numerous observations which we shall discuss, and published
a memoir, translated into French by M. Thierry-Mieg, about the
results of his practice. The interesting extracts from this memoir
will be better placed in the chapter devoted to the study of theoreti-
cal explanations.
I shall quote here only the summary which he gives of the
phenomena observed in persons subjected to the action of com-
pressed air:
Slackening of the respiration and the circulation; very probably,
greater absorption of oxygen by the skin and the lungs; increase of
exhalation of carbonic acid; decrease of cutaneous transpiration and
pulmonary exhalation; increase of the urinary secretion, which elimin-
ates more uric acid and less phosphate; improvement in hematosis
and nutrition; increase in the energy of the muscular apparatus and
in the vital capacity of the lungs. (P. 33.)
In 1860 von Vivenot began the series of his publications on the
physiological and therapeutic effect of compressed air. His numer-
ous notes and memoirs 1X led him to write a lengthy work,12 which
appeared in 1868; it is by far the most important work which has
been published on this subject.
The larger part of his researches were made at the baths of
Johannisberg. Since the altitude was fairly great, the average
barometric pressure was only -741.17 mm.; as the compression used
rose to 318.07 mm., the total pressure was 1060.24 mm. This pres-
418 Historical
sure was reached in the apparatus in 20 minutes; it stood there
for 1 hour; 40 minutes were used for the return to normal pressure.
Respiration. The most important of Vivenot's memoirs is the
one which he devoted to the study of the changes in the mechan-
ical and chemical reactions of respiration. Since in his long work
he added to it only details of observation of moderate interest, I
cannot do better than to reproduce the principal passages of the
original work, published in 1865; it is a sort of analysis of Vivenot
by Vivenot himself.
We shall, however, limit ourselves here to reporting the obser-
vations relating to changes in the respiratory rhythm and the pul-
monary capacity; the chemical part, since it is much more closely
connected with questions of theory, will be better placed in the
following chapter:
If we examine a person first under normal pressure, then under
compressed air, we may detect, by percussion, auscultation, and pal-
pation, changes in the size and location of different organs, corre-
sponding to the new conditions of pressure. If we have noted, under
normal pressure, the position of the diaphragm and the upper limit
of the liver corresponding to as deep an inspiration and expiration as
possible, as well as the boundaries of the dullness of the heart, we find,
in both cases, the diaphragm and the liver situated lower under com-
pressed air; the drop is from 1V2 to 2 centimeters under an increase of
pressure of 3/7 of an atmosphere; the dullness of the heart has become
less extensive and has taken another form (that of a sickle, the con-
vexity of which is turned towards the sternum). At the same time,
the cardiac impulse seems less vigorous to a palpating finger, and
the ear in auscultation finds the heart-sounds weaker, as if they were
further away. There is sometimes produced in compressed air a me-
chanical expansion of the lungs, as a result of which the diaphragm
and the liver are pushed down, while the anterior lobe of the left
lung places itself above the corresponding half of the heart. For this
reason the dullness of the heart diminishes, its form is changed, and
the impulse and sounds of this organ seem weakened.
The increase in capacity of the lungs, shown by these facts, is
demonstrated in another manner. In compressed air, the spirometer
shows us a rather considerable increase of the respiratory capacity. The
average of a great number of experiments, made during a stay of an
hour and a half under the pressure of 1 and 3/7 atmospheres, gave in
me an increase of 108.07 cubic centimeters, in Dr. G. Lange 133.3, in
Dr. Mittermaier (after a single experiment) 121.0 and in M. H. .y
99.2. Now since my pulmonary capacity on the average is 3425 cubic
centimeters, that of Dr. Lange 3950 cc, that of Dr. Mittermaier 4159
cc, and that of M. H. .y 2910 cc, it follows that the increase in lung
capacity was in me 1/31.7, in Dr. Lange 1/29.7, in Dr. Mittermaier
1/35.4 and in M. H. .y 1/29.3.
We see that these results do not differ perceptibly from each
Medical Apparatuses 419
other and they indicate an average increase of pulmonary capacity
equal to 1/31.5 of the volume of the lungs, or 3.3%. As the maxi-
mum of this increase, I found in myself 254 cc, in Dr. Lange 200
cc, in M. H. .y 223 cc, in M. R. 270 cc. and even 500; 686 in a patient
with emphysema, M. G., whose average respiratory capacity was 2268
cc, that is, about 2/9 to 2/7 of the total respiratory capacity.
The effect obtained, as we see, is doubled; on the one hand, we
have in the same volume more atmospheric air, and on the other
hand, our enlarged lungs are capable of receiving a greater volume
of this compressed air. If then my average respiratory capacity is
3425 cc. under normal pressure, the same volume of compressed air
at 1.37 atmospheres would represent by itself 4893 cc. of normal air.
And as, under increased pressure, my lungs inspire an average of
108.1 cc more, which is equivalent to 154.5 cc. of normal air which
I inspire, then 3425 + 108.1 cc. = 3533.1 cc of compressed air, it fol-
lows that the volume of air drawn in by the deepest inspiration
under the effect of compression is equal to 5047.5 cc. of air at normal
pressure ....
Experimentation has proved that after a stay of 2 hours in com-
pressed air, the pulmonary capacity, even under normal pressure, does
not return to its original volume, but retains an increase which, in
me, rose on the average to 50.53 cc, at the maximum to 183 cc;
in M. H. .y on the average to 57.6 cc, at the maximum to 124 cc.
It next gave this interesting and astonishing result that the sub-
sequent effect is not a passing effect, but that it is partly permanent,
so that as a result of the use of compressed air for two hours every
day, one enters the pneumatic apparatus with a pulmonary capacity
which, naturally disregarding physiological variations, every day
exceeds what it was the day before by 20 to 30 cc. For instance,
from April 30 to September 19 inclusive, that is, in 143 days, after
122 treatments with compressed air taken during this time, my pul-
monary capacity under normal pressure had risen successively from
3051 to 3794 cc (under compressed air even to 3981 cc), a figure
which it had already attained August 12 after 91 air treatments, and
at which it remained almost constantly. The vital capacity of the
lungs therefore in me in three and a half months had made a progres-
sive increase of 743 cc, that is, nearly a quarter of its original volume
(24%). A similar result was observed in other persons. In M. H. .y,
the respiratory capacity had risen after 11 days use of compressed
air from 2900 cc. to 3085 cc; in M. de K., in 4 days, from 3252
cc. to 3664 cc; in M. G., a patient with emphysema, in 17 days,
from 2202 cc. to 2550 cc; the respiratory capacity of the latter had
even reached 2836 cc. in compressed air.
A suspension, even for several days, showed no retrogressive effect,
and three weeks after my last stay in compressed air, the spirometer
showed that my respiratory capacity had remained at 3800 cc. Like-
wise percussion, by Professor Duchek, revealed after 3 weeks that
the forcing downward of the diaphragm and the liver for 2 centi-
meters and the decrease of the dullness of the heart, matters dis-
cussed above, were maintained.
420 Historical
It is quite evident that such changes in the pulmonary capacity
must have some effect upon the sum total of the respiratory func-
tions, and particularly upon the number, the depth, and the rhythm
of the respirations.
The number first:
In my first experiments published several years ago, I had al-
ready found the number of inspirations diminished; my long present
series of experiments has confirmed this result, as being constant, one
may almost say. The decrease in the number of inspirations varies
with the individual. On the average, it increases proportionately
with the original number of respirations; in general, it is 3, 2, 1,
to Vz respirations per minute. As a maximum, I have observed in
two patients with emphysema, whose inspirations rose to 33 per
minute, a decrease which was respectively 16 and 11 inspirations.
Upon the return to normal pressure, the number of inspirations
increases again a little, but without reaching its original figure. In
that also, the effect of the compressed air is not merely temporary,
but has a somewhat permanent quality. This is more evident when
we consider the frequency of the respiration in a longer series of
observations. Then we note that the respiration is always less -fre-
quent the day after than on the day before. As it undergoes a new
decrease as a result of each new treatment with compressed air, the
result is this certain and constant fact that the continued use of com-
pressed air lessens the frequency of the respiratory movements every
day, up to a certain limit.
My own respiration, after three months of daily use of com-
pressed air for two hours every day, had fallen from 20-16 per min-
ute to 4.5 under normal pressure, and even to 3.4 in compressed air.
When it had reached this degree of slackening, it remained
stationary during the subsequent experiments (still slackening a little
under the influence of pressure) and even now, while I am writing
these lines, although 5 months have passed since then, my respira-
tion does not exceed the noteworthy figure of 5.4 inspirations per
minute. The same result, though less remarkable, because the series
of experiments was shorter, was noted in observations made on other
people. In M. H. .y, the number of inspirations had fallen in 12 days
successively from 21 to 16 and in compressed air to 13 per minute.
In Dr. Lange, after 4 treatments taken in 11 days (in spite of interrup-
tions of several days) from 19 to 16, and in compressed air from 14
to 6; in M. G., an emphysematous patient, after 14 treatments taken
in 19 days, from 20.5 to 15.5; in Dr. D., also emphysematous, from 33, on
the second day, to 18, and in 5 days to 10.4.
It is during the first days that the respiratory frequency lessens
most noticeably and most promptly; later, the decrease becomes
slower and the differences less great.
If we compare the result obtained as to the frequency of the
respiration with the result given us by the spirometer, it will be dif-
ficult not to observe that there is between the two a well-founded
relation, that the frequency of the inspirations is inversely propor-
Medical Apparatuses 421
tional to their amplitude, so that while this amplitude increases, the
frequency of the respiration diminishes. The increases of the capacity
of the lungs, under the effect of compressed air, is the cause of the
slackening of the -respiration; or, in other words, the slackening of the
respiration is an inevitable consequence of the increase of the pul-
monary capacity, because the inspiration and expiration of a greater
volume of air necessarily require more time.
Then the depth:
We could imagine three different methods as possible. A com-
pensation might be established between the frequency and the depth
of the inspirations by the fact that the amplitude of the respiration
could be less than under normal pressure, since a greater quantity of
air enters in the same volume, and the frequency of the respiration
could nevertheless be reduced also; or, in the second place, the com-
pensation could be established, for the same reasons, by less numerous
inspirations, keeping the same amplitude. Finally, in the third place,
there might be, in spite of the supplying of a greater quantity of air,
as a consequence of the compression, a slowing down and an increase
in depth of the inspirations. This last condition appeared a priori
most probable if we took into account the increase in amplitude of
the respiration, as we had observed it, and it should occur particularly
in persons whose pulmonary capacity had been pathologically reduced.
To settle these questions, I used an apparatus constructed for the
purpose, which could be attached around the thorax, and followed
its movements of inspiration and expiration, the increase of the cir-
cumference of the thorax being indicated in millimeters by the sep-
aration of two movable needles. This greater or smaller increase in
the thoracic circumference served to measure the greater or smaller
depth of the inspirations. In each of the thirty-nine experiments
made with this thoracometer, the depth and the number of the in-
spirations were noted for fifteen consecutive minutes, long enough
for the effect of the will or a slight error of observation to be negli-
gible. The experiments were always made comparatively in atmos-
pheric air and in compressed air; and as the frequency of my inspira-
tions was then from 7.67 to 4.40 per minute, from 115 to 66 observa-
tions were needed in each experiment, making a total of about 3000
numbers concerning the mobility of the thorax.
The measurement made as explained above justifies the state-
ment that in me, on the first day of the experiment, the thoracic
expansion, that is, the increase of the thoracic circumference produced
by an ordinary inspiration was 12.39 mm. at normal pressure, and
at the beginning of the maximum pressure 15.68; after an hour of
this same pressure 17.22; and at the end, under normal pressure
18.14, whereas the frequency of the inspirations had dropped from
7.67 to 6.07, 5.80, and even 5.60; there had been produced therefore
under the influence of the compressed air a progressive decrease of
frequency at the same time as a progressive increase in the depth of
the inspirations, which continued even after ordinary pressure had
been restored. The next day, the thoracic expansion under normal
pressure was 14.92; the third day, 17.84; the fifth day, 18.98; a fort-
422 Historical
night later it had risen to 21.86, while the number of inspirations un-
der atmospheric pressure had dropped respectively from 7.67 to 7.07,
6.40, 6.53, and 5.00 per minute, and the respiratory capacity on the
contrary had risen from 3350 cc. to 3400, 3474, 3498, and 3644.
The experiments made on MM. de K. . . and Dr. M. . . gave the
same result. In the latter, the frequency of the inspirations had
fallen during a single experiment in compressed air from 7.6 to 6.5
per minute, whereas his thoracic expansion had risen from 19.28 to
23.02 mm., and his respiratory capacity had likewise risen from 4159
to 4280 cc. This result proves that under the influence of compressed
air the depth of the inspirations as well as the capacity of the lungs
increase, whereas the frequency of the inspirations diminishes in in-
verse proportion.
The expansibility of the thorax, as it has been investigated up
to the present, is only that which corresponds to an ordinary inspira-
tion, not modified by the will, and as it is produced as an effect of the
prolonged influence of the compressed air.
However, the modifications already noted suggest also a change
in the conditions of the voluntary inspirations, and this change is to
be verified by the increase of the total circumference and of the volun-
tary expansion of the thorax before and after the prolonged action of
the compressed air. If the capacity of the lungs had really been in-
creased, the last measurements should indicate an increase in the
circumference of the thorax, not only during the greatest expirations,
but also during the deepest inspirations; and if by a prolonged stay
in compressed air the ease of a habitually more vigorous respiration
had been gained, the maximum expansibility of the thorax should
also have increased. This result is also verified by the figures. My
thoracic circumference, which on April 30 after the deepest inspira-
tion had been 85 centimeters, was 86.5 on September 1; and after the
strongest expiration, it was 77 cm. on April 30, and 78 cm. on Septem-
ber 1; so that my pulmonary expansion was 8 centimeters on April 30,
and 8.5 cm. on September 1.
The general increase of the lung capacity, as it was indicated by
the spirometer, and the increase of the vertical diameter of the lungs,
as it was determined by percussion, receive an additional demonstra-
tion by the increase of the thoracic circumference.
Finally, the proportions of the respiratory periods:
The inspiration is made more easily, being favored by the increase
of pressure, by the extensibility of the pulmonary tissue, and by the
compressibility of the intestines, whereas more force is needed for
the expiration so as to contract the lungs which are more distended
and to expel the greater quantity of air expired. That is why the
expiration is made with more difficulty and more slowly than in the
normal state. While under atmospheric pressure the duration of the
inspiration is to that of the expiration almost as 4:3, this ratio be-
comes in compressed air almost as 4:6, 4:7, and even 4:8 and 4:11.
However the resistance to the expiration finds partial compensa-
tion in the more powerful contraction of the abdominal muscles
Medical Apparatuses 423
which the compression supports in their action. Through the effect
of this contraction, the first half of the expiration is made quickly
and energetically; but the second half is made so slowly and so im-
perceptibly that there is a sort of pause between the inspiration and
the expiration. This pause which should in any case be added to the
expiration and the length of which has been, according to my ob-
servations, from two to six seconds, is increasingly longer as the in-
spirations are fewer.
Vivenot has tried to express these different modifications of the
respiratory rhythm by the following graph (Fig. 9) , which I borrow
from his long work (p. 251), and in which the solid line indicates
the normal respirations, and the dotted line the respiration under
compressed air, the whole during fifty-some seconds.
Circulation. The memoir published by Vivenot in 1865 in the
archives of Virchow contains detailed information about the modi-
fications in his pulse under the influence of compression. These
explanations are accompanied by numerous graphs obtained by
means of the sphygmograph of M. Marey; I reproduce here the
most characteristic:
A rapid glance at the curves shown below reveals that under
the influence of compressed air they undergo considerable modifica-
tions in their original forms; closer attention shows that all parts of
Fig. 9— (bis).
the curve are so essentially changed that their analysis requires care-
ful dissection of separate segments of the curve.
We see that in all the curves without exception, under the in-
fluence of compressed air, the height of the curve decreases. The line
of ascent, more or less abrupt originally, becomes more oblique;
the apex seems more rounded, and because of the lessening of the
amplitude, the line of descent, still less abrupt, finally is bent into the
form of a wave which is more or less convex on the right. Because
of the decrease in the height of the curve, the angle formed by the
intersection of the ascending line and the descending line of the pulsa-
tion inscribed and which under normal atmospheric pressure measures
about 45° is considerably blunted; and also, because of the more
oblique direction of the line of ascent, the apex of the top of the
424
Historical
curve is further prolonged backward ... so that the curve as a whole
assumes the form of the segment of a sphere.
The changes which we have just described are proportional to
the strength of the air pressure and to the duration of the stay in
compressed air and consequently are more marked and more pro-
nounced as the air pressure is carried higher and the stay in the ap-
Fig. 10
paratus is lengthened. We find then that the indications produced
after twenty minutes of maximum pressure, that is, the visible ob-
liquity of the line of ascent, the shortening of the wave, the rounded
flattening of the top, and the transformation of the wavy line of
descent into a straight line or a simple convex line, after an hour
and a half, that is, after an hour of exposure to the constant maxi-
mum pressure, take on a still more evident character, so that the
tracing of the pulse finally presents, so to speak, only a straight line.
Fig. 11
In these four figures letter a indicates the sphygmographic
tracing obtained under normal pressure; b is the tracing while the
pressure is rising in the apparatus; c, during the period of constant
compression; d, after return to normal pressure. Fig. 11, ai was taken
while the pressure was increasing; Ci while it was decreasing.
Upon return to normal atmospheric pressure, immediately after
the treatment, the curve resumes its original form, or only partially
returns to it, or, somewhat frequently, the change when it has once
begun in the blood curve undergoes a downward movement. Figure
9 expresses all these different phases.
Medical Apparatuses
425
In no case did I find this change in the curve lasting, but this
effect, agreeing with. the results which we obtained for the pulse rate,
in favorable cases is prolonged for a few hours. Curve d, in Figure
12, furnishes an example of a curve rising and regaining its original
form, not immediately, but twenty minutes after the return to nor-
mal pressure.
Fig. 12
To establish the truth of the assertion which we have already
accepted, that the vestige, remaining after the treatment, of an
effect upon the tracing has already disappeared after several hours,
one may use curves obtained upon myself May 26, a day on which I
had had two experimental treatments in compressed air. If we com-
pare the curve obtained on that day before the first treatment, at
eight o'clock in the morning (Fig. 12, a) with the corresponding
Fig. 13
curve of the second treatment, that is, taken at half-past two in the
afternoon (Fig. 13, a), one can note no essential difference between
these two pulse tracings. After this period of four hours and a half
there is no perceptible sign of the effect still noticeable at ten o'clock
on curve b of Figure 13; still less should we expect to find the persist-
ence of this effect from one day to another.
Now, to grasp the value of the differences so far found, we should
picture the different elements of the curves as the expression of these
changes.
The irregularity in the ascending line which coincides witn the
systole of the heart is produced by the blood wave expelled by the
contraction of the heart, and this wave, tending to spread in all direc-
tions, partly urges on the blood current and partly exerts an excentric
pressure upon the walls of the vessels which it stretches. The ascend-
ing part of the curve (line of ascent) therefore corresponds to the
arterial diastole. The more easily the blood flows in the capillaries,
426 Historical
the more quickly does it move in the arteries, and the more easily
does the heart contract, since the blood pressure representing the
resistance opposed to the systole of the heart becomes weaker. It is
well known that every muscle contracts so much the more easily and
quickly, in proportion as the execution of this movement requires less
expenditure of energy. Consequently, in such a case, the arterial
expansion will take place in so much less time; and if the time from
the rise of the blood pressure to its maximum increase is very short,
that will be expressed in the steepness of the ascending line of the
curve; and if the period of time is so short that it cannot be measured,
then the line of ascent will appear completely vertical, as is almost
always the case in the normal state.
When, on the contrary, on the tracings made in compressed air
we observe that the line of ascent is becoming oblique, we conclude
that the resistance opposed to the blood wave produced by the systole
of the heart has increased at the same time that the flow of blobd is
checked in the capillaries; that consequently the systole of the heart
is less rapid, that the blood wave reaches the arteries slowly, and
that consequently also the dilatation of the arteries does not take
place suddenly, but progressively.
The apex of the curve which we do not wish to consider as a
mathematical point, but as the convergence of the ascending and
descending lines, shows us the moment when the artery, having
reached the maximum of its dilatation by the blood distending it,
resists by means of its own contractility the pressure of the blood
which acts upon it, and by its contraction exerts a new impulse on
the blood.
If the resistance which the blood wave meets in the arterial
trunks at a distance from the heart decreases a little, then the flow
of the blood in the direction of the current, from the heart to the
periphery, becomes easy and rapid, and the pressure of the blood
in the arteries decreases rapidly, and the arteries can contract rapidly.
The more marked this tendency is, the more acute the apex of the
tracing appears, as we can see, for example, in the normal pulse.
The contrary takes place in compressed air, and the original
acute angle changes, as we have seen, into a more or less obtuse angle,
and even into an arch, which takes place, if, on account of the con-
siderable obliquity of the line of ascent, the highest vertical point
intersects the middle of the curve.
Consequently the increase of resistance already expressed in the
ascending part of the curve, by its obliquity under the influence of
the compressed air, is communicated or transmitted also to the apex
of the curve (p. 557-560) ....
The descending wave of the curve of the pulse, which corresponds
to the diastole of the heart, shows us the decrease of the blood
pressure in the arteries, coinciding with the closing of the semilunar
valves, and with the simultaneous flow from the large arteries into
the capillaries, that is, the arteries gaining the victory in their struggle
against the pressure of the blood, and by means of their elasticity,
through the transformation of their expansive energy into active
energy, contracting to the minimum limit of their caliber. The vary-
Medical Apparatuses 427
ing appearance of the line of descent, according as it bends, becomes
straight, or oblique, or convex, or falls perpendicularly, shows us how
much more or less easily the blood passes through the capillaries.
The tracings of the pulse taken at normal atmospheric pressure, be-
fore entering the compressed air (tracings I - XVII of Vivenot)
show this more or less accentuated characteristic oscillation which the
finger detects only in the most pronounced cases, which is called
dicrotism, and which consists of two or, more often, three oscillations
of the wave. (P. 562)
Whereas we have found polycrotism as a more or less marked
peculiarity of the normal pulse at ordinary pressure, it appears from
our curves that the compression of the air causes the polycrotism to
disappear and transforms the wavy line of descent into an almost
straight line or one which is more or less convex.
So we find the proof of a congestion of blood in the vessels and
of a hindrance of the capillary circulation, in the descending line of
the curve as well as in its ascending part and its apex.
Whereas, as Marey has shown and has proved by an example in
a tracing made in a case of heart disease (Fig. 86 of Marey), the
dicrotism is proportionately greater as the wave expelled by the
ventricle is smaller in proportion to the caliber of the artery, we con-
firm, for our part, this proposition in regard to the dicrotism, be-
cause, as it appears from the preceding discussion, the arteries, which
are compressed by the outer pressure and therefore convey very little
blood, are nevertheless very full of blood in proportion to their les-
sened caliber.
Upon return to normal pressure, at once the original figure of the
line of descent reappears, and the simply convex line resumes its
previous polycrotism, or rather the form which has been produced per-
sists for a time, one or two hours, and then yields and gradually re-
gains its original appearance (See above, Fig. 9).
In our analysis of the pulse tracings we have hitherto omitted
one circumstance, that is, the somewhat important change in the
amplitude of the curve under the influence of compressed air.
For the sake of clarity, we have delayed analysis of it until we
reached the subject of the energy of the pulse, better named the size
of the pulse, which refers to the vertical height of the blood wave,
that is, the maximum height, and which, according to Marey, is pro-
portional to the energy of the pulsation. As we have concluded from
the agreement in the tracing of the curves which we have collected
for far, the amplitude of the pulse is lessened by the stay in com-
pressed air, and often loses from 4/5 to 5/6 of its original height, so
that the whole series of pulsations traced is often changed into a line
in which the separate waves are hardly perceptible.
This decrease of amplitude is proportional to the compression of
the air and to the length of the stay in the compressed air, and so
the minimum amplitude is noted particularly at the end of the stay
in the compressed air; it happens by exception that after the return
to normal pressure the amplitude remains stationary, and returns
to the normal state after a long stay under ordinary pressure. It is
also exceptional to see the amplitude, after reaching its minimum,
428 Historical
begin to rise gradually during the period of constant maximum
pressure, without reaching its original height, however.
Moreover, the changes which the pulse undergoes here are ex-
plained by and are perceptible to the touch, because in most cases the
pulse which is normal before the entrance into the pneumatic ap-
paratus is almost imperceptible to the touch of the finger in com-
pressed air; it is really the pulsus debilis. We should note in regard
to this last point that the changes of the pulse described above
in a pulsus longus, such as we have seen appear in the pneumatic
apparatus, and Which are observed in normal air pressure in certain
morbid processes, such as aneurisms and embolisms, give a deceptive
sensation to the finger, so that even when the vertical height of the
pulse remains identical, as Marey observed (p. 243), the pulse will ap-
pear stronger in proportion as the blood wave is more gradual, which
is expressed by the rise and fall of the blood pressure in the vessels;
but since in our case, in compressed air, the decrease of the strength
of the pulse indicated by touch is also confirmed by the decrease in
vertical height of the tracing, the decrease of the strength of the
pulse in itself must be considered certain.
We should now have to show the cause of this decrease of the
strength of the pulse in compressed air, as it appears from our re-
searches; we might well think first of the weakening of the action of
the heart itself, and of the occasional circumstance of the decrease
of the strength of the pulse in compressed air, a weakening which
perhaps is caused by the rise in resistance, which the increase of
the atmospheric pressure, compressing the whole of the peripheral
vessels, produces in the arterial system; in support of this hypothesis
we might mention data which I reported under other circumstances
and in another place; in fact, inspection and palpation of the heart
show its weaker impulse; auscultation of the heart gives an identical
result, and the sound appears further away, so to speak.
However, these data in no way show and prove that a change
has taken place in the strength of the heart impulse, for, on the one
hand, we find it extremely difficult to get an almost certain and
demonstrated proof of the changed intensity of the contraction of the
heart, and, on the other hand, the weakening of the heart impulse
and of the heart sounds, noted by sight, hand, and ear during the stay
in compressed air, can be only apparent; and, as I have already shown
in the dissertation mentioned above, can be only a simple effect of a
displacement of the heart, caused by the compression of the air and
connected with the increase of the capacity of the lungs and the pass-
ing of the anterior layer of the left lung in front of the heart. (P. 564-
567).
So far we have discussed only the form of the isolated wave, with-
out taking into account the combination of the successive waves, and
yet this complex phenomenon requires some explanations.
Let us draw a line from the beginning to the end at the base
of the wave or across its apex; we shall then have what Marey called
a line of the whole (gemeinsame linie), which may give us some in-
formation about certain changes in the pressure of the blood and in
the distention of the vessels. This line which, as we have said, varies
Medical Apparatuses 429
according to certain changes in the attitude of the body, may display
a total or partial change in its form and in its direction. The first
case appears following a change of long duration in the blood pressure
and in the distention of the vessel, and is evidenced by a consider-
able modification of the whole line in reference to the original form
of the pulse, whereas a frequent change in blood pressure and vascu-
lar distension, such as takes place, for example, under the influence
of an irregular respiration, finds expression in the more or less
marked and more or less frequent incurvations in a series of rises
and drops of the pulse line. Now since this line, according to Marey,
indicates that an obstacle to the blood flow increases the distension in
the arterial system at some point, we had to investigate whether that
took place in compressed air because of the compression of the super-
ficial vessels, and whether the obstacle or the difficulty recognized
by us in the arterial circulation by the change in the line of ascent
also produced a change in our line of the whole, and found its ex-
pression in its rise (oblique ascent of the whole line) in compressed
air.
After preparing the instrument for this purpose, according to the
rules established in our preceding experiments made with the use of
the sphygmograph, and arranging things in such a way that the reg-
istering stylus should be placed just in the middle of the band of
paper, at an equal distance from the upper and the lower edge, and
after releasing the clockwork, I thus made in the open air a tracing
of the pulse in the exact middle of the paper; but I did not have the
same success with operations in compressed air. Although the in-
strument had not been lifted, and no change had been made in the
attitude of the arm or the position of the instrument, the registering
stylus under the influence of the compressed air moved from its
original situation and rose; it even rose so high that it passed above
the upper edge of the paper band, and it had to be lowered, by a
slight movement of the hand, to the level of the paper so that a
tracing could be obtained. By this experiment we demonstrated:
for the radial artery a general rise of the blood tension and of the
vascular distention independent of that which can be observed in an
isolated pulsation.
As far as concerns the influence of the respiratory movements
shown by the arched incurvations of the pulse line, it is slight and
imperceptible enough to go unnoticed by superficial observation. It
is very apparent only when one takes deep inspirations and when
there is a difficulty in respiration.
In consequence of changes produced in the size of the thorax
by the inspirations and expirations on the one hand, and, on the
other, as a result of the rising and falling of the diaphragm, which
alternately contracts and enlarges the abdominal cavity and Ihe
thoracic cavity, and of the consequent change in distention of the
abdomen, a stronger pressure is produced alternately in the thoracic
aorta and the abdominal aorta; the result is a variable distention in
these vessels which is then communicated to the remote arteries.
And so, as I have shown elsewhere, under the influence of com-
pressed air, we observe a slackening of the frequency of the respira-
430 Historical,
tion which, maintained by the daily repetition of this same influence
of the pressure of the air, increases from day to day to a certain
figure; moreover, the respiration is easier in compressed air; it be-
comes calmer and more complete; and thus certain respiratory dis-
turbances are quieted. So whereas in the open air the influence of
•the respiration was shown in the curve of the pulse, in compressed
air this influence should be weakened,, that is, the curves and arches
of the line of the pulse should, under this influence, lose frequency
Fig. 14
and intensity, as, moreover, we can see in Figure 14, which, made May
1 on an emphysematous patient aged 44, in a at normal pressure
shows noticeable variations in the curves expressing the pulsations,
which show great difficulty in respiration, whereas, under the in-
fluence of compressed air in b, the intensity of the curve has fallen
so considerably that the pulse line almost becomes horizontal, and
that at the same time there is a greater number of pulsations for
one respiration than in a, and by this change the abatement of the
previous respiratory difficulty is indicated.
The existence of this change in the respiratory curve under the
influence of compressed air may be considered the rule, and we rarely
find the opposite state. (P. 578-580.)
As to the number of pulsations, Vivenot summarizes in the fol-
lowing words 423 observations made upon himself:
In the morning between 6 and 7 o'clock, when I awoke, my pulse
rate was 65.22. After I had breakfasted in bed, this number rose to
its maximum, 81.20; at the time of entering the pneumatic apparatus
it was only 79.03. Under the influence of compressed air, it fell to
between 75.43 and 71.66; on return to normal pressure it was still
72.41, and in the course of the day my pulse did not rise to the figure
given before my entering the apparatus.
This decrease in the pulse rate in compressed air was noted 375
times in my 423 observations; 18 times there was no change; 30
times, an increase in the pulse rate. (P. 532).
Vivenot observed that the congestion of the vessels of the con-
junctiva disappeared wholly or partially through compression.
The examination of the retina in a person who had been given
atropine also showed him that the vessels of the eye are emptied
of blood in compressed air.
Besides, he made five direct observations upon a tame white
Medical Apparatuses 431
rabbit in regard to changes in the circulation in the ears and the
conjunctiva. I copy the details which he gave on this subject,
because they do not seem to me to justify the conclusions which
he drew from them and which were accepted on his authority.
I. (a). Normal pressure:
The rabbit quiet and free. The ears erect, swollen with blood.
The vessels of the conjunctiva congested. The iris and particularly
the pupil very red.
(b). During the increase of pressure:
Vessels of the conjunctiva thinner and paler. Loss of. color in the
iris and the pupil.
(c). During the constant maximum pressure:
By transparency, the vessels of the ears empty of blood; the
largest are hardly visible; shortly after, the ear is quite pale and limp
and the vessels have completely disappeared,
(d). During the decrease of pressure:
The ear and the conjunctiva remain pale.
(e). Under normal pressure, immediately after treatment:
After the treatment, even an hour after, the ears are empty of
blood, pale and limp.
II. (a). The vessels- of the ears are moderately congested.
(b). At the beginning, a greater congestion of the arteries and
the veins of the ear; later the iris first grows pale and then loses its
color.
(c). The ears remain pale; the iris is darker; the pupil redder.
III. (a). The vessels of the ears are moderately congested; the
iris and the pupil are a beautiful red.
(b). Swelling of the vessels and particularly of the veins of
the ears, the largest of which are dilated.
(c). At the beginning, no change noticeable in the color of
the iris and the pupil. The vessels of the ear alternately grow pale
suddenly and fill up again; however, some time afterward, they are
definitely pale and remain empty of blood,
(d). The ears are still pale and limp.
(e). Some hours after the treatment, the ears are still quite
empty of blood, pale, and limp.
IV. (a). Long before the treatment, the ears are rather empty of
blood.
(b). The vessels of the ears are alternately congested and pale;
finally they remain pale.
(c). Because of the darkness in the apparatus, the color of the
pupil cannot be observed.
(d). The ears still pale.
(e). The pupil seems to become dark red. The ears are well
filled with blood.
V. (a). The conjunctiva congested at isolated places. The vessels
of the ear moderately congested.
(b). The congestion of the conjunctiva and the vessels of the
ear partly disappears.
432 Historical
(c). Vessels of the ear and the conjunctiva obliterated; the
ears pale; sometimes congested in an instant. Because of the increas-
ing darkness, the color of the pupil and that of the iris cannot be de-
termined.
(d). The ear and the conjunctiva remain pale; finally, no vessel
can be perceived. (P. 587).
So, Vivenot concluded, under the influence of compressed air
the blood diminishes in the vessels of the periphery of the body.
After the details which I have just reported about the changes
in the two great physiological functions of respiration and circula-
tion, changes which are at the same time the most important and
the easiest to verify, I think it will be sufficient to reproduce the
summary which Vivenot himself gives of all his observations.
Unfortunately, the statement of the data in it is so thoroughly
mingled with the theoretical ideas which the author conceived to
explain them that it would be impossible to separate them from
each other; but the difficulties resulting from this confusion will be
settled in reading the following chapter.
Summary of the Physiological Phenomena.
1. Impressions in the ear.
2. The change in the tone of the voice, the tones rise in pitch;
the difficulty in pronunciation, the impossibility of whistling, some-
times slight stammering.
3. Smell, taste, and touch' lose their keenness.
4. The negative pressure in the inspiration and the positive
pressure in the expiration increase.
5. The convexity of the abdomen decreases because of the
compression of the intestinal gases.
6. For the same reason, the diaphragm and the base of the lungs
fall.
7. The lung, during inspiration as well as during expiration,
comes around in front of the heart.
8. Thence comes the decrease of the cardiac impulse upon pal-
pation and the faintness of its sounds upon auscultation.
9. The pulmonary vital capacity increases. At 3/7 of com-
pression, it is increased in a half-hour by 73.40 cc. on the average,
and in 1V2 hours by 105.27 cc, that is, 3.30% of their original
dimensions.
10. On return to normal pressure, the increase in pulmonary
capacity decreases, but the lungs do not regain exactly their orig-
inal volume.
11. Repeated treatments bring every day an increase of the
pulmonary capacity; more at the beginning than at the end. After
3V2 months of air treatments my pulmonary vital capacity had be-
come greater by 743 cc, that is, increased one quarter without any
loss of the contractile power of the lungs.
Medical Apparatuses 433
12. The changed activity of the diaphragm and the thorax per-
sists after the end of the experiments.
13. These increases do not take place solely in extreme respira-
tions; they are observed in the regular respiration, and the diaphragm
then is also lower than in the normal state.
14. The respiration becomes less frequent. The number of the
movements decreases by 1 to 4 per minute. This effect continues a
little while after the return to normal air.
15. 16, 17, 18. These sections repeat for frequency what was
said about depth in 10 to 13.
19. The inspiration is faster, the expiration slower; the first
part of the latter is rather short, but the second becomes so slow
that there seems to be a pause.
20. The proportion of carbonic acid contained in the expired
air increases; a respiration with 3/7 of an atmosphere above the
normal contains on the average 22.26% more carbonic acid than at
normal pressure.
21. This increase therefore is not in exact proportion to that
of the pulmonary capacity, which is 3.3%.
22. It takes place not only in exaggerated respiratory move-
ments but also in quiet respiration.
23. Upon comparing this increase of carbonic acid with the de-
crease of respiratory frequency, we see that there is definitely a
greater quantity of carbonic acid given off and consequently of
oxygen absorbed.
24. The result of this is that after a series of treatments in com-
pressed air, the venous blood appears brighter, the temperature of
the body increases (from 0.1° to 0.4°), the muscular energy is
greater, hunger appears, and, in spite of a larger amount of food,
the weight of the body lessens through emaciation; however, if the
pressure is not too great and if one eats a great deal, one may, on
the contrary, grow fat.
25. The pulse rate drops by 4 to 7 per minute; this decrease
is still more marked when there was an abnormal acceleration.
26. On return to open air, the pulse resumes its normal rhythm.
27. However, when the frequency of the pulse was due to some
respiratory difficulty, a permanent drop may be the result of treat-
ment by compressed air.
28. The decrease of the frequency of the pulse seems to be the
result of the purely mechanical action of the compressed air; the
increased pressure on the surface of the boody increases the re-
sistances met by the blood waves sent out by the systole of the
heart; the systole then becomes more difficult, with the result of a
decrease in the number of pulsations.
29. The curve of the radial pulse undergoes changes in form;
its height lessens, the line of ascent is less steep, more oblique, the
apex more rounded, the line of descent loses its wavy form and be-
comes straight or slightly convex. There is therefore a shrinkage
of the vessels, and consequently of the quantity of blood which
they contain, an increase in resistance to the systole of the heart,
and a greater difficulty in the capillary circulation.
434 Historical
30. On return to normal air, the tracing gradually regains its
original form.
31. The radial pulse seems changed to the touch; it becomes
small, filiform, almost imperceptible.
32-33. These sections relate to an experiment which will be re-
ported in the following chapter.
34. The action of the heart in compressed air is not stronger;
but we do not know whether it diminishes, although that is probable.
35. The sphygmographic curve, while the pressure is increasing,
is above that obtained in normal air. There is, therefore, in this
phase an increase in the total pressure of the blood, at least in the
radial artery.
36. Experiments made on animals, on the pressure of the
blood in the carotid artery, by means of the hemo-dynamometer gave
no result. It is probable that when the air pressure has become
constant, a new degree of equilibrium is reached, the action of the
heart which has become less strong brings a decrease in the aortic
system.
37. The decrease in caliber of the vessels of the conjunctiva,
of the retina ,and of the ears of rabbits, the loss of color in the
pupil and the iris of white rabbits, the pallor of workmen who
labor in compressed air, directly prove the ebbing of the blood from
the periphery towards the center.
38. Thence come the decrease, of the intra-ocular pressure,
the contraction of the pupil, the lessened sensation of the pulse in
the ear and the jaw, the decrease of the redness in the membrane of
the tympanum, the improvement in cases of erysipelas, and finally
the decrease in size of scrofulous strumae.
39. A manometer placed in the jugular vein showed that the
venous pressure diminishes in compressed air. (Vivenot did not
make any experiments on this; he depends upon an experiment of
Panum, which he himself finds unsatisfactory and poorly carried out.
(P. 414).
No direct experiments have been made in regard to the effect
of compressed air upon the venous and lymphatic systems. But
it is certain that it can only be stimulating; moreover, the negative
pressure, which is increased, acts also on the heart and the large
vessels.
40. The temperature in the armpit increases while the air is
being compressed, it reaches its maximum with the compression. Dur-
ing the stage of constant pressure, there is also an increase of rectal
temperature.
41. It is shown by our experiments that a part of the blood is
driven back from the periphery of the body; the organism has there-
fore at its disposal a quantity of blood which must rush to the organs
which are more deeply situated, such as the brain, the spinal cord, the
muscles, the alimentary canal, the liver, the spleen, the kidneys, and
the uterus. Thence result, for the brain, the heaviness of the head,
the slight deafness, and the yawning; for the alimentary canal, the
hunger and the increased rectal temperature; for the muscles, the
increase of muscular energy and of the axillary temperature; for the
Medical Apparatuses 435
kidneys, the greater quantity of urine. Those complex symptoms, in
which the outer cold also has some influence, act only within physi-
ological limits.
42. That is why the compression of the air causes no serious dis-
turbance in the circulation of the blood, even when it is carried to 4%
atmospheres.
43. The same thing cannot be said of the stage of decompression,
which, when.it is too sudden, causes annoying and even very danger-
ous disturbances in the distribution of the blood.
44. The stay in compressed air is therefore less dangerous than
the return to open air, which causes congestions, hemorrhages, pains
and particularly disturbances of equilibrium of different sorts in the
circulatory system, which, by the development of gas in the blood,
may even cause a stoppage of the circulation and consequently a
sudden death.
45. The means to be used in the case of these symptoms is a
rapid return to compressed air. (Zur Kenntniss, etc. P. 489-495.)
The series of Vivenot's works attracted the attention of physi-
ologists and physicians to the interesting symptoms which he was
the first to note or which he described with more accuracy than
the preceding authors. The publications followed each other
rapidly.
Freud 13 noted a considerable increase in his pulmonary capacity.
After 30 air treatments, it had risen from 3100 cc. to 3600 cc; this
increase still persisted 5V2 months later. There were only four
respirations per minute.
Elsasser,14 who did his research in the apparatus of Gmelin, at
Stuttgart, summarized the observations of his predecessors and
his own in regard to the respiratory rhythm in the following
statements:
1. The total value of the respiratory movements in a given time
is diminished . . . . ; 2. The decrease affects partly the frequency,
and partly the amplitude of the movements; the more nearly the
frequency approaches the normal, the less deep the respirations are;
if they are very rare, they become deeper; 3. In very deep inspirations,
a greater quantity of air enters the lungs than at normal pressure.
(P. 26.)
Moreover, his memoir seems to be only a sort of summary of
the former works of Vivenot. It is especially devoted to thera-
peutics.
But in the front rank of the authors who, after Vivenot, con-
sidered these questions, we must mention Professor Panum. The
work of the Danish scientist is exclusively of a physiological
nature.15 We shall give it an important place in the following
436
Historical
chapter; here, we shall mention only observations relating to the
physico-mechanical phenomena of circulation and respiration.
Respiration. The first phenomenon discussed is the enlarge-
ment of the pulmonary cavity in compressed air:
Respiration is always deeper than at normal pressure. This effect
often lasts for 24 hours or more and increases with the repetition
of the air treatments. In one person whose inspiration, under normal
pressure, amounted to 400 to 700 cc. (an average of 480 cc), the first
treatment of 35 cm. raised it from 650 to 800 cc. (average 750 cc); the
second took it on the average to 900 cc.
The frequency of the movements had fallen from 13 - 14.5 to 11.5
per minute. (P. 153)
Here, moreover, is a table which expresses the modifications
shown by respiration in normal air and in compressed air, follow-
ing different voluntary rhythms of respiration:
COMPRESSED AIR
NORMAL PRESSURE
Quantity of
Number
Quantity of
Number
air in each
of
air in each
of
respiratory
respira-
respiratory
respira-
movement.
tory
movement.
tory
In cubic
move-
In cubic
move-
centimeters.
ments.
centimeters.
ments.
Quiet respiration
631.8
13.5
563.5
14.2
Quiet respiration
745.6
10.8
679.5
11.9
Deep and strong
respiration
1326.4
8.4
1314.6
. 9.9
Respirations as
deep and as
rapid as
possible
2301.6
6.4
1846.7
12.7
Respirations as
slow and
creating as
little circu-
lation of air
as possible __
1216.4
4.2
930.3
5.8
As for the respiratory rhythm properly so-called, Panum states
that "the relative duration of the inspiration and the expiration
is similar in compressed air and at normal pressure." And in sup-
port of this statement, which contradicts what we previously re-
ported on the authority of Vivenot, he gives a tracing of respiratory
movements directly recorded.
Circulation. Panum reports the observations of Vivenot and
Sandhal, and admits the slowing down of the pulse. He tried to
make experiments on two dogs to study the modifications of the
manometric pressure of the heart; but they gave no result.
The decrease of the blood flow in the capillaries is proved,
Medical Apparatuses 437
according to him, by the fact that a toothache disappeared in
compressed air. However, observations on the conjunctiva and
the ears of rabbits showed nothing definite; besides, he says, there
are too many causes of complications. But what is the immediate
cause of these modifications in the circulatory acts?
The decrease of the pulse and of the tension must be due to an
effect on the heart action. Is this effect the result of respiratory-
changes? Does it depend on the pressure exerted on the muscles and
the ganglia of the heart? Or on some other circumstance? I do not
venture to give an authoritative opinion.
The work of G. von Liebig 1G contains the account of the experi-
ments made at Reichenhall in the apparatuses of the Mack brothers.
The average pressure at Reichenhall is 72 to 73 centimeters; in the
apparatuses it varied from 100 to 130 centimeters.
G. Liebig first observed, as did so many others, that respiration
slackened in compressed air. In Kramer, one of the persons whom
he observed, it fell from 10 to 7 per minute, and remained at this
figure under normal pressure: but in the other, Mack, one of the
proprietors of the establishment, who was accustomed to com-
pressed air, the difference was only from 4.3 to 4.1.
The respiratory amplitude was also modified in the first subject.
It rose from 0.819 liters to 1.073 liters, and remained at 1.068 liters.
But in the second, the change was only from 1.437 liters to 1.489
liters and we may consider it as non-existent.
Mayer ,7 made similar observations on a lady affected with
dropsy and on himself:
He noted the usual phenomena. But (contrary to Vivenot) he
found a constant slackening of the pulse, which he explains by in-
creased circulatory resistances (increased pressure on the heart and
the vessels); the respiration was also slowed down. The vital capacity
of the lungs increased in a perceptible manner which seemed to be
persistent. The increased combustion raised the temperature in the
patient from 37.3° to 37.7°.
The work of Marc 18 is more interesting, although it deals only
with an observation which Dr. Stachelhausen, who had been suf-
fering from hemoptysis and emphysematous asthma for four years,
made upon himself.
After treatment for a month, a considerable improvement was
made; but I have no intention of dwelling on pathological details.
The most striking detail of the observation is the marked change
caused in the number of heart beats and of respiratory movements;
I have summarized the author's figures in the following table:
438
Historical
JUNE
T23|24|25|26|27I28I29130
(Out of apparatus |80|78|76I80|80|72|80|80
Pulse I I I I II I I
(In apparatus |64|60|60|68|68|68|75|74
I I I I I I I I
Respiratory (Out of apparatus ^|24|24|20|20|20|17|18|18
Movements (In apparatus |12|12|13|12|13|13|12|12
JULY
>| 3| 4| 5| 6| 7| 8| 9]10|11|12|13|14|15|16|17|18|19|20121
7<5170|76|76|7
I I I I
18 18 18|18|16
riTi
)|80|80176|80|80|80
S0|7S76]80]
75|68|66|75|80|72|7e
I II I I I I I I I
16|l4|15|14|16|16|16|14|14|16|14|14|14|14|14|14
12|12|14ll2i|12|12|12in|10|12|ll|12.|ll|12|ll|ll|12|12|l2|lO|10
So two things are to be noted: first, the sudden decrease of the
number of heart beats and of respiratory movements by the effect
of compressed air; the decrease in the number of the latter, even
in the open air, as long as the treatments were being given, where-
as the pulse rate did not change.
The pulmonary capacity measured on the spirometer was in-
creased 550 cc.
June 22, before the beginning of the treatments 1450 cubic cent.
June 29, during the treatments 1600 cubic cent.
July 8, during the treatments _ 1800 cubic cent.
July 15, during the treatments r 1900 cubic cent.
July 21, during the treatments F 2000 cubic cent.
It is regrettable that Marc specified neither the degree of the
air compression nor the length of time his patient stayed in the
apparatus.
1 Here is a list of the chief works published on the therapeutic use of compressed air.
I did not include those which I am quoting and analyzing in the present and the following
chapter. This list shows the astonishing variety of ailments in which the new treatment has been
Pravaz, Mem. sur V emploi du bain d'air comprime dans le traitement des affections tuber-
culeuses, des hemorrhagic capillaircs et des surdites catarrhales. Acad, de Med. de Paris, Dec.
6, 1837. Cpt. R. Acad, des Sciences, Vol. VII, p. 283, 1838.
Id., De I'influence de la respiration sur la sante et la vigueur de I'howme. Lyon, 1842.
Id., Memoire sur V emploi de la compression au moyen de I'air condense dans les hydarth-
roses, et sur la possibility de reduire certaines luxations spontanees de la hanche. Lyon, 1843.
Dubreuil, Bains d air comprime. Marseille, 1848. # .
De la Prade, Rapport sur le memoire relatif aux bains d'air comprime, in Essai sur I emploi
medical de I'air comprime, par Pravaz. Lyon, 1850.
Poyser, On the treatment of chronic and other diseases by baths of compressed air. Asso-
ciation Med. Journal, September 9, 1853. . .
Devay, Du bain d'air comprime dans les affections graves des organes respiratoires. Gazette
hebd.. 1853.
Schtitz, Brief liche Mittheilungen aus Nizza. Deutsche Klinik, February, 18o7._
Bottini, Dell' aria compressa come agente tcrapeutico. Gaza. med. italiana, Stati Sardi. 185i.
A. Simpson, Compressed air as a therapeutic agent. Edinburgh, 1857.
Haughton, On the use of the compressed air baths. Dublin, Hosp. Gaz.. 1S58.
Pravaz fils, Des effets physiologiques et des applications therapeutiques de I'air comprime.
Lyon, 1859. ,
Gindrod, The compressed air-bath, a therapeutical agent in various affections of the respira-
tory organs and other diseases. London, 1860.
Lippert (in Nizza), Ueber Paris nach Nizza, medicinishe Reiscskizze. Deutsche Klinik.
October, 1861.
Trier, Om Bode i fortoettet luft. Copenhagen, 1863.
G. Lange, Der pneumatische apparat. Vienna Med., Wochenschift, August, 1863.
Levinstein, Beobachtungen iiber die Einivirkung der verdichtcten Luft bei Krankheiten der
Respirations-und Circulations-Organ e. Berl. W ochenschrift, 1864. _ .
Freud, Der pneumatische apparat. Wirkung und Anwendung der comprimirten Luft tn
verschiedenen Krankheiten. Vienna, 1864.
Fischer, Errichtung eines Luft compression Apparates zu Hannover. 1864. _
Josephson, Die therapeutische Auzvendung der comprimirten Luft. Deutsche Klinik, 1864.
Levinstein. Grundzuge zur practischen Otiartie mit Berucksichtigung der neucsten thera-
peutischen Technik, etc. Berlin, 1865.
Smoler, Die Anwendung der comprimirten Luft in Krankheiten der Gehororganes, Osterr.
Zeists. f. pract. Heilkunde. Vienna, 1865.
Storch, Jagttagelser over Virkningen af comprimirct Luft ved behandhngen af Brysttidelser.
meddelte fra Rasmussens medico-pneumatiskc Austalt. Hospitals-Tidende VIII. Aarg. Copen-
hagen, 1865.
Medical Apparatuses 439
Sandahl, Nyare undcrsdkningar och iakttagelscr rorandc de fysiotogiska och tcrapentiska
verkningarne of bad i fbrtdtad luft. Hygiea. Stockholm. 1865.
Id., Bertittelse om den mcdiko-pncnmatiska anstaltens verksamhet i Stockholm under aren
1863 och, 1864. Stockholm. 1865. ,
Freud, Vortrag iiber der pneumatisch Apparat, ilnd seme liirkungcn vn I icnna Doctoral
colleg. Zeitsch f. pract. Heilk., 1865. . ,.
Bertin (Emile). Analyse de trois brochures sur I'air comprime. Montpellier medical. 1866.
Kryszka, £><?r atmosphdrische Druck. Voch. d. Zeitsch der K. K. Gesellsch. der Aerzte in
Wien, 1866. ,. - , ,
Pravaz fils, De f application de I'air comprime an traitment de la surdite catarrhale.
Grenoble, 1866. . ..„„«, „-,,-. L c
Brunniche. Berctning om A. Rasmussens medico-pncumatiske Anstalt t 1866. Bibhotek for
Lager. Copenhagen, 1867.
George v. Liebig, Der pneumatische Apparat su Rcichcnhall und andere Fortschrttte des
gen. Kurorts. Bayer, arstl, Intell. Blatt; 1867.
Td., Der pneumatische Apparat su Reichenhall wahrend der Saison von 1867. Ibid., 1868.
Sandahl, Des bains d'air comprime. Court apcrcu de leurs cffcts physiologiques et thera-
pcutiques. Stockholm, 1867.
Roussaux, De I'aerotherapic. These de Paris, 1868.
Levinstein, Zur Casuistik der Anwcndung der verdichteten Luft bci Lungcnkrankcn. Kisch s
Bain. Zeitung; 1868, Bd. II.
Gent, Emploi therapeutique de lair comprime. Bull. Acad, de Med., November 20. i860.
Freud, On the effects of compressed air on the organism in general and especially upon
diseased organs of respiration. New York Med. Gas., February, 1871.
G. v. Liebig, Die Wirkung der crhorten Luftdrucks der pneumatischen Kammen auf der
Menschen. Deutsche Klinik, 1872, No. 21 and 22.
Id., Ueber Blutcirculation in den Lungcn und ihrc Bcsiehungen cum Luftdruck. Arch. f.
klin. Med., June, 1872. ■ .
Runge, Zur Theorie der Wirkung der comprimirten Luft auf den Orgamsmus. Wien. allg.
tned. Zeit.; Vienna, 1868, Nos. 12 and 13. ...
Pundschu. Ueber den pnuematisch. Apparat als Kunnittcl fur Brustkrankc. Vienna Medical
Press.; Nos. 48 and 49. Vienna, 1S68.
Franchet, Du bain d'air comprime. Theses de Paris, 1875.
Fereol, Applications therapeutiques de I'air comprime. Gaz. tned., 1S75, p. 258.
2 Tractatus physico-medicus de atmosphera et acre atmospherico. Cologne, 1816.
3 Loc. cit. Arch. gen. de Med.; Second series, Vol. IX. p. 157-172 1835.
4 Recherchcs sur les effcts des variaitons dans la prcssion atmosphcrique a la surface du
corps. Cpt. R. Acad, des Sciences, Vol. VI, p. 896; 1S38.
5 Sur faction therapeutique de I'air comprime. Cpt. R. Acad, des Sc, Vol. XI, p. 26; 1840.
6 See list of works on therapeutic use of compressed air_ in Note 1.
7 Essai sur V emploi medical de I'air comprime. Lyon-Paris, 1850.
8 De I'air comprime comme agent therapeutique. Lyons, 1854.
9 Om verhningarne af fartatad luft pae den mcnskliga organismen, i fysiologiskt och tcra-
peutiskt hdnseendc. Medicinskt Archiv utgivet of L'drare vid Carolinska Institut et in Stockholm.
Vol. I, Chap. I; p. 1-205; 1862. Since I was unable to procure the original memoir, I quote
from the extensive analysis of it given by Von der Busch in Schmidt's Jahrbucher der Gesamm-
ten Mcdicin, Vol. CXX, p. 172-180; 1863.
™ Die comprimirtc Luft als Hcilmittel. Aerztl, Intel!. Bl. 16, 19. Extract in Canstatt s Jahr.,
1863; Vol. V, p. 135. .
11 a. Ueber den Einfluss der verdnderten Luftdruckes auf den menschlichen Orgamsmus.
Virchows Archiv fur pathol. Anat. und Physiol, und Klin. Medicin, Vol. XIX, Berlin, 1860, p.
492-521.
b. Ueber die therap. Anwendung der verdichteten Luft, und die Errichtung eines Luft
Compressions Apparates in Wien. Wochenblatt der Zeits. der K. K. Gesellschaft der Aerate
su Wien. Numbers of July 9, 16, and 23, 1862.
c. Ueber die Aufstcllung eines pneumatischen Apparates in Wien. Allgememe Wiener
Medic Zeit. Numbers of February 13 and 10, 1863.
d. Ueber der Einfluss der verstdrkten und verminderten Luftdruckes auf der Mechanismus
und Chemismus der Respiration. Medic. Jahrb. der Zeitsch. der K. K. Gesellschaft der Aerste
zu Wien. May, 1865. Translated in part by Thierry-Mieg; Gas. Med de Paris. 1868.
e. Ueber die Zunahmc der Lungen capacitdt bei thcrapeueischer Anzvendung der verdich-
teten Luft. J-irchozv's Archiv. Vol. XXXIII; Berlin, 1S65, p. 126-144.
f. Ueber die Vcrdnderungen im arteriellcn Stromgebiete unter den Einfluss der verstdrk-
ten Luftdruckes. Virchoiv's Archiv. Vol. XXXIV; Berlin, 1865; p. 315-391. Translated by Lorain:
Le Pouls, Paris, 1870.
g. Ueber die Uerdnderungn der Korpenvdrme untcr den Einfluss der verstarkten Luft-
druckes. Medicinische Jahrb. der Zeitsch. der K. K. Gesellsch. der Aerste su Wien. February.
1866.
h. Ueber Luftdruckcuren. Der Cursalon. Vienna, 1867. Nos. 6 and 7.
i. Beitrdge sur pneumatischen Respirationstherapie ; Allgem. Wien. med. Zeitung. Vienna.
1868.
12 Zur Kenutniss der physiclogischen Wirkungen und der therapcutischen Anwendung
der verdichteten Luft. Erlangen, 1868; octavo of XII-626 pages.
13 Erfahrungen iiber Anzvendung der comprimirten Luft. Wiener Med. Press, 1866.
14 Zur Theorie der Lebenscrscheinungen in comprimirten Luft. Stuttgart, 1866.
15 Panum's memoir appeared first in Danish, in 1866. I quote from the German translation
published by the author himself: Untersuchungen iiber die physiologischen Wirkungen der com-
primirten Luft. Pfluger's Archiv' f. Physiologie ; Vol. I, p. 125-165, 1868.
16 Ueber das Athmen unter erhbhtcn Luftdruck. Zcitschrift f. Biologic; Vol. V, p. 1-27,
Munich, 1869.
17 Bericht uber eine Versuchs-Sitsung in comprimirten Luft. Petcrsburgh med. Zeitsch.,
XII, extract in Gurlt's und Hirsch's Jahr. 1870, Vol. I, p. 210.
13 Beitrdge sur Erkenntniss der physiologischen und therapeutischen Wirkungen der
Bdder in comprimirten Luft. Berliner Klinischc Wochenschrift, 1871, p. 249-251.
Chapter III
THEORETICAL EXPLANATIONS AND
EXPERIMENTS
Even if the experiments and the theories which we reviewed in
speaking of the effect of diminished pressure were numerous,
varied, contradictory, sometimes strange and almost incompre-
hensible, at least their purpose was to answer a single question:
What is the cause of the symptoms of decompression? It is other-
wise with those which we shall summarize in the present chapter,
and their discussion will necessarily betray the confusion into
which those who expressed them have fallen.
The data which we have hitherto reported show that in truth
the phenomena displayed by persons subjected to the effect of
compressed air are extremely varied and appear under conditions
which can hardly be compared, perhaps are absolutely unlike. In
fact, we must take account, at least when the compression has
risen to a certain degree, not only of the phase of compression but
also of that of decompression, the dangerous effects of which were
soon shown by observations made by the workmen themselves.
It was these effects which first attracted attention by their strange-
ness and their severity. The changes which the compressed air
itself causes in the different physiological functions' are not very
great, within the limits hitherto observed, and to verify them
attentive and sustained observation was required, aided by the in-
strumental resources used today by physiology and pathology. Some
physicians have distinguished between the two classes of phe-
nomena, and have tried to explain them by different reasons; but
others have confused them in common theories, so that it would
not be possible to subdivide this chapter, as personally we should
like to do.
Let us add that laboratory experiments on animals have been
440
Theories and Experiments 441
much rarer than for decreased pressure. The reason is not hard
to find; on the one hand, the problem seemed much less interest-
ing, since it was not connected with questions of temporary or
permanent habitat for man; on the other hand, the necessary in-
strumental apparatus is more complicated and more expensive,
and the experiments entail some dangers.
The first author in whom I found theoretical suggestions about
the manner in which compressed air should act on living beings is
the physician-mathematician Borelli, who, in his celebrated treatise
De motu Animalium,1 sets down the following proposition:
Prop. CXXV. Probable causes of the suffocation produced in
different ways in air which is thick and too much condensed.
Following the knowledge of his time, Borelli here confuses the
effect of compressed air with that of air laden with "ethereal,
earthy, aqueous, oily, igneous, saline, etc., particles, as happens in
the vapor of coal .... and in the cavern of Lake Agnanus Puteolis."
. . . However, he devotes a special section to the effect of "pure air,
brought to the highest degree of compression, ut in folle lusorio sit;"'
I will not deny (he says) that it might be dangerous to breathe,
because the extremities near the bronchial tubes and the delicate
Malpighian vesicles might be distended and torn by the excessive
elasticity, from which dangerous disturbances might result. Moreover,
the passage and circulation of the blood would be prevented by it,
because the expiration could be made only with great difficulty be-
cause of the excessive resistance of the ambient air. (P. 246.)
Borelli made no experiments.
It is in the notes which van Musschenbroeck added to the
translation of the Memoirs of the Academy del Cimento 2 that we
find the first indication of experiments made on animals subjected
to the action of compressed air:
I shall first report (the Dutch physicist says) what happened to
animals placed in air much denser than it is at about sea level. M.
Stairs shut up a rat in air twice as dense; it lived for five hours;
however, after five more hours, it died. But when he had put another
rat in air much denser, he observed that it died suddenly. He reports
that a fly, in compressed air which made the mercury rise sixty inches
above its usual height, was in good condition the third day, and even
flew about; but its other companions died.
M. Derham placed a sparrow in a receiver, in which he com-
pressed the air; because it did not hold the air tightly, he repeated the
compression from time to time; the sparrow lived for three hours;
then, when set at liberty, it seemed to have suffered no harm. Next he
put in a titmouse and a sparrow, he compressed the air twice as much;
after an hour these birds were as well as when they were put in; then
442 Historical
they began to pine, in two hours more they were sick, and three
hours afterwards they died.
I also placed a duck in a receiver, in which I made the air three
times denser than that of the atmosphere; however it remained gay
for an hour, and seemed to have suffered no inconvenience.
I next shut in three perches and a trout with a great quantity of
water together with some living earthworms; I made the air in the
receiver three times denser; prolonging the experiment for six hours
I observed the following things: the first hour all the little fishes
swam very well, often took new air at the surface of the water, and
yet did not eat any worms; after an hour, the trout seemed less
lively, and was more quiet; half an hour afterwards it shook its
fins, yet its back was turned upwards as in the natural state; the
perches during this time were swimming gayly; five hours afterwards,
the trout, still having its back turned upward and resting freety in
the water, had died; one perch became more quiet; after the sixth
hour, it also was near death, but was lying on the bottom with its
back turned upward; then after I had opened the vessel and let the
air out, the two perches were alive and very gay; but the two dead
fish were floating lying on their backs; the worms all this time had
lived under water, and being taken from it, they were quite sickly.
This experiment was made November 10, 1730.
I call attention to the interesting conclusions which Musschen-
broeck draws from the experiments which he has just reported:
It follows from these experiments that animals can live longer in
compressed air than in natural air without its being renewed; for
although the enclosed animals consume a little air, a portion of its
elasticity is lessened; nevertheless, in compressed air there is enough
air left, and the elasticity is great enough: so that in the inspiration
the vesicles of the lungs expand well and easily, and the blood circu-
lates very freely in the arteries and the veins of the lungs. However,
animals finally die in this compressed air; but what is the cause of
that? It is not the lack of air, it is not the loss of its elasticity; :Cor
the mercury shows by the index that there is still enough of it left.
But they die because the exhalations from the body of the animal
are harmful to its lungs, or to its life, or because something is con-
sumed out of the air which is necessary to the maintenance of life,
and which must be constantly mingled with the blood. This last idea,
however, can hardly be well founded, because the celebrated M.
Boerhave has proved by irrefutable arguments that no air inspired
into the lungs can pass from the vesicles into the blood vessels: that
is why we must conclude that the particles which we exhale are
harmful to us, and that those which issue from other animals are also
harmful to them and act like a poison; and so we understand why
divers shut up in a bell, a cask, or other vessel must always be
refreshed with new air so that they may breathe comfortably; and
why miners who work in deep mines are very uneasy if new air is
not constantly sent them in the mines by means of blowers or some
other ventilators. (P. 58.)
Theories and Experiments 443
Hallery gave space in his physiology to experimental data and
those already revealed by observation of diving bells; he explains
them in the following manner:
If the air is much denser .... the blood, which flows in vessels
which are themselves more compressed, undergoes more friction there;
this air will inflate the lungs better, and will bring to the left heart
the stimulus which will make it contract better ....
A condensed air is useful and increases the energies of the body.
Animals have lived without discomfort in air reduced to a quarter
and an eighth of its volume. Under the diving bell, in a denser air,
one can live, and a slower respiration is sufficient. A rat lived longer
in compressed air than in ordinary air ... .
Yet there are limits beyond which compressed air is harmful.
That happens in the diving bell; in which, when the depth increases,
the water enters and compresses the air again. Then respiration is
hampered, the belly is compressed, the air enters the auditory meatus
painfully, the arms are bound as if with a rope, the membrana
tympani is sometimes broken, and blood issues from the ears and the
nostrils; finally the heart experiences such resistances that the flow of
the blood is almost checked, and some have died thus. A rat died in
air reduced to a twentieth of its volume. (P. 194.)
Experiments similar to those of Stairs, Derham and Musschen-
broeck were made at the beginning of this century by Achard,4
who reports them in the following words:
I have made some experiments on the germination of seeds in
compressed air. The result is that the more compressed the air is,
the more quickly do the seeds germinate; the difference is considerable.
At the same time I made experiments on the length of life of animals
in air condensed to different degrees, and I found that in air three
times as dense as the atmosphere an animal lives, under circumstances
otherwise similar, and in equal volumes of air, five times longer than
in atmospheric air. It should be noted that when the air is suddenly
compressed to a density about triple, the animal falls into a state of
inactivity and lethargic sleep, which apparently is a consequence of
the pressure exerted on the brain. After this state has lasted a ldhger
or shorter time, the animal regains its natural activity, and then falls
into a state of great uneasiness which increases gradually until death.
It is also noteworthy that the animal economy feels no ill effect from
this state of compression; I have kept birds for an hour in air reduced
to one fourth of its volume, and then returned them to the open air;
they were in very good condition and showed no sign of inconvenience.
(P. 223.)
Brize-Fradin, after writing the history of diving apparatuses,
as we have seen, and after reporting the sensations experienced
there, tries to explain these phenomena, and to form a clear idea of
the situation in which the man breathing in compressed air is
444 Historical
placed, from the physical and physiological points of view. The
passage below is truly very interesting:
The diver is placed in a medium which compresses the whole
system.
How does he get into equilibrium with these combined powers?
How can he surmount them?
The logical solution is found in the characteristics and the prop-
erties of the vital force. It is necessary to consider in man what forms
the essence of life, that is, this energy which often modifies the laws of
nature, and reduces them to what they should be to constitute life;
it is the primordial law of the action, the conservation and the har-
mony of organized beings.
Analysis does not permit us to resolve into its elements the nature
of this vital force attributed to a subtle, invisible spirit; but it is
enough that its existence should be proved by its properties, its con-
stant relationships. (P. 176.)
To do justice to Brize-Fradin we must say that he is not satis-
fied with this vague declaration, and that, not content with meta-
physics, he tries to determine the effects of this vital force upon
the diver:
The denser air, enclosed in the bell, brings to the lungs a greater
quantity of oxygen; immediately a greater quantity of heat is produced
there: this air, endowed with elastic force, rushes into the lungs; the
respiratory organ, the walls of which touch the pleura on all sides,
gains a greater capacity; the gas opens the angles which the vessels
form there and makes the passage of the blood through them freer
and easier; it increases the speed of the circulation, and multiplies in
the fibers of the muscles these inner frictions which are powerful
causes of heat. The levators and the intercostals contract quickly;
the ribs rise; the diaphragm falls; not only is the equilibrium de-
stroyed, but the elastic power of the air is repelled by this inner
energy which raises the muscular contractility to the highest degree,
and which follows the effects of the caloricity.
We know that the pressure of the air upon a surface is equal to
a column of water thirty-one feet high; it has been calculated that
the effect of the pressure, in a man of average height, is equal to a
weight of 36,000; but this weight is counterbalanced by the vital force
and by the reaction of the elastic fluids which are part of our organ-
ism. Since the variations of the atmosphere are successive, they affect
us in a hardly perceptible way; but if a sudden change occurs, the
rupture of equilibrium has a very marked effect upon the animal
economy; if a man mounts to great heights, he experiences discomfort,
fatigue, drowsiness: so if we wish to account for the difference be-
tween the effects of the weight of water and those of the elastic force
of the compressed air at a depth of sixty feet, we must again resort to
this force whose principle is unknown, but which changes and modifies
the general laws, and puts into the class of demonstrated truths that
which at first glance seemed hard to explain. (P. 177.)
Theories and Experiments 445
We see that his physiological attempt has been unsuccessful
and that he must return to explain, not the symptoms, but the re-
sistance of the diver to "this force whose principle is unknown,
but which changes the general law." It was really useless then
to take so much trouble to try to apply these laws.
Further on, mentioning the two principal inconveniences of the
diving bell, the pains in the ears and the confinement of the air,
Brize-Fradin proposes as remedies:
1. To put cotton in the auditory canal, to imitate "the Creator,
omniscient in his works, who distributed in the organ of hearing
this cerumen which . . . assists the harmony of the sound waves"
(p. 131);
2. To bring oxygen into the bell by means of a force-pump
"when the sea has been drained out of the bell by these air-
drums"; but he recommends "that only exact quantities should be
introduced, which should never exceed a tenth of the quantity of
vital air ... . for an excess would produce a harmful sensitivity and
disturbance" (p. 183).
I mention only for the sake of the record the passage in which
Halle and Nysten 5 speak of the effect of compressed air; in fact,
they merely say:
In deep mines, the effects resulting from the compression of the
air would be more wholesome than harmful, because of the increased
quantity of air in the same volume. They would make respiration
less frequent, because each inspiration would take effect upon a
greater mass of this fluid.
The increase in the weight of the atmosphere should, it seems,
produce less perceptible effects than its decrease, and the pressure
which tends to compress all its parts seems less harmful to our
organism than their excessive expansion.
For the same reason I report the opinion of Jaeger,0 who does
not seem to base it on any direct observation:
Air compressed to a very high degree may cause sudden death,
because it produces apoplexy with hemorrhage and prevents the re-
turn of the blood to the upper parts and the heart. (P. 97.)
The experiments of Poiseuille 7 are much more important.
In the course of his researches, so conspicuous for the scientific
spirit and the accuracy which he manifests in them, this author
asks himself whether variations in pressure have an effect upon
the circulation of the blood. To settle this important question, he
uses a pneumatic object-holder composed of an unyielding box,
446 Historical
furnished with glass plates, in which the pressure can be increased
or diminished:
The animal prepared so that the capillary circulation can be seen
is placed in the instrument, and the apparatus itself is placed under
the object-glass of the microscope; then one can observe the changes
which a greater or less ambient pressure can cause in the capillary
circulation. In salamanders, frogs, their tadpoles, very young rats,
and young mice, the arterial, capillary, and venous circulations showed
no change when enduring pressure, even sudden pressure, at 2, 3, 4, 6,
and 8 atmospheres, and conversely. Moreover, the circulation continued
to go on with the same rhythm under a pressure of several centi-
meters of mercury in salamanders, frogs, and their tadpoles. Upon
placing in the apparatus very young rats and very young mice (we
know that mammals, during the first days of their lives, can remain
a few hours without breathing), we could see by the perfect sound-
ness of circulation in these animals then placed in a vacuum, how
unfounded was the opinion of the physiologists who think that with-
out atmospheric pressure circulation is not possible; but the atmos-
pheric pressure and the respiratory movements in conjunction are the
accessory causes of the flow of the blood, as M. Poiseuille demon-
strated in one of his preceding memoirs.
Poiseuille, we see, considers at the time the effect of the increase
and that of the decrease of pressure upon the rapidity of the circu-
lation; he states that they are non-existent.
The explanations of M. Maissiat 8 also tend to consider the two
questions simultaneously. We saw, in Title I (page 234), that he
thinks that the principal factor is the intestinal gases, the volume
of which must change with the pressure of the air. After consider-
ing their expansion as speeding up circulation and respiration, and
as forcing the blood to the skin, he adds:
Opposite effects and a return of the blood towards the vessels in
deeper positions will be caused, if, on the contrary, the outer pressure
on the animal increases; the effect will be medically sedative, soothing
both the respiration and the circulation. (P. 254.)
A few years later, Hervier and St.-Lager,9 at the suggestion of
Pravaz, made the first experiments attempted with the purpose of
finding out whether the organic combustions are expedited during
the stay in compressed air.
The authors reach the singular result formulated in the follow-
ing conclusion, a result which they do not support by any figures;
the method by which it is obtained and which gives not the quan-
tity of carbonic acid exhaled, but only its proportion in the air
expired, is, I must say, very faulty: 10
The quantities of carbonic acid exhaled in compressed air rise
Theories and Experiments 447
above the proportions of the normal state up to the pressure of 773
thousandths; above this figure, the lungs exhale less carbonic acid
than before.
And here is the rather vague explanation which they give for
this contradiction:
At a low pressure, since the chemical effect dominates the me-
chanical influence, endosmosis finds in the conditions of pressure a
circumstance favorable to the development of the respiratory functions
without exosmosis being hampered by too strong a pressure .... and
therefore a growing increase in the exhalation of carbonic acid follows.
At a higher pressure the mechanical effect neutralizes and destroys
the chemical influence, to the point of preventing gaseous exosmosis
in the compressed air, without hindering the absorption of gases,
however.
It is this storing of carbonic acid by the blood, under the in-
fluence of the compressed air, which would explain, according to
our authors, how:
The baths of compressed air increase the exhalation of carbonic
acid outside the bath; this effect, which persists for several hours
after the treatment, is more perceptible two or three hours after-
wards than immediately after the bath.
This would be owing to the fact that:
The abnormal expansion of the pulmonary vesicles, as an effect
of a sufficiently strong pressure in compressed air, lessens the energy
and elasticity of the respiratory organs .... whereas, when after
the bath the mechanical influence suspends its action, the energy of
the lungs soon returns to its normal state, and by means of the gaseous
exosmosis which is no longer hampered, casts off in the form of
carbonic acid all the oxygen which it had absorbed in the bath under
the influence of endosmosis.
Pravaz,11 from whose book we have already quoted (page 415) ,
after listing the favorable changes which the stay in compressed air
brings to the exercise of several important physiological functions,
finds that these considerable advantages have three causes of dif-
ferent types:
A. The amplitude of the inspirations is increased for two
reasons:
1. If it is certain that, under the ordinary conditions of life, the
inspiration is far from having the extent which the anatomical posi-
tion of the thoracic walls would permit, we cannot doubt that in a
great number of persons, and particularly in those who, because they
lead a sedentary life, need only a moderate encounter with the atmos-
phere for the purpose of hematosis, the retractility of tissue has
448 Historical
considerably reduced the maximum capacity which the lungs can
attain under ordinary pressure, and consequently the usual expansion
of the pectoral cavity; then is it not manifest that in increasing this
pressure and thus raising to greater power the energy which struggles
against the reaction of the lungs, we should extend the upper limit of
its own development and consequently that of the expansion of the
thoracic framework under the effort of the inspirator muscles, an effort
which promptly loses its power when the tendency towards a vacuum,
which takes place between the two pleura during the inspiration,
passes a certain limit?
2. Since the increase of the atmospheric pressure has the effect
of compressing the abdomen, of increasing the elasticity of the intes-
tinal gases and consequently their reaction against the effort of the
diaphragm, this muscle meets a more stable point of support and
changes the usual mode of respiration, forcing the ribs and the
sternum to take a greater part in the mechanism of this function. In
fact, the expansion of the thoracic cavity vertically is thus diminished;
but this reduction is more than compensated for by the expansion of
the chest, following its antero-posterior and lateral diameters, and, far
from being lessened, the volume of air admitted by each inspiration
is increased. In fact, in the mode of respiration which takes place
principally by the descent of the diaphragm, the capacity of the chest
increases only according to the simple proportion of the successive
vertical diameters, measured laterally, for the middle part of the dia-
phragm remains almost stationary; whereas in the costo-sternal respi-
ration, the enlargement of this cavity takes place in the compound
proportion of the product of the original horizontal diameters to the
product of the same diameters expanded. (P. 11-12.)
B. Hematosis is expedited:
Is it, as is generally thought, because the compressed air contains
in a given volume a greater absolute quantity of oxygen that it expe-
dites and improves the oxygenation of blood? (P. 21.)
Pravaz then compares the recent experiments of MM. Regnault
and Reiset with the former statements of Allen and Peppys, and
he adds:
If, between these contradictory statements, one leaned towards the
former, as guaranteed by experimenters with the reputation of greater
exactness, one would not be puzzled for an explanation of how com-
pressed air can give other results than pure oxygen, or oxygen merely
offered in greater quantity for pulmonary absorption.
In fact, Lavoisier and MM. Regnault and Reiset collected their
observations at ordinary pressure; now we know, on the authority of
M. Biot, that the quantity in weight of gases dissolved in a liquid
increases proportionately to the pressure which these gases support.
There is therefore in the action of compressed air on the organism
an element other than the multiplication of the molecules of oxygen
in a given volume; this element is a mechanical force greater than
that which acts upon the gases under experimentation at the ordinary
Theories and Experiments 449
pressure of 0.76 meters; this difference between the conditions of
absorption makes us anticipate a corresponding difference between
the results given by an inspiration of pure oxygen and one of merely
compressed air. (P. 23.)
Experimentation, according to him, confirms this idea of the
theory. This experiment is the one of Hervier and St.-Lager
(page 446) , whose conclusions Pravaz accepts, and whose apparent
contradictions he explains as follows:
The endosmosis of oxygen, which is the principal duty of respira-
tion, is aided by all circumstances which increase the solubility of this
gas in the blood; now the increase of atmospheric pressure is evidently
included in these circumstances, according to the experiment reported
by M. Biot; so in compressed air there must be a supersaturation of
the venous blood by oxygen, but this phenomenon cannot manifest
itself immediately by a greater exhalation of carbonic acid, for the
exosmosis of this gas is kept down by the same mechanical force
which increases the absorption of oxygen.
When the respiration is once more taking place in normal atmos-
phere, the superoxidation of the blood corpuscles which was produced
during the compressed air bath necessarily gives rise to symptoms of
vital exaltation and to the elimination in greater quantity of the
gaseous product of the combustion of carbon, which has become
more active because this gas is no longer subjected to the increased
pressure which restrained its expansibility ....
Analogy leads us to think that the same thing is true of nitrogen
as of oxygen. Has its increased absorption some advantage for metab-
olism? I am inclined to think so, judging by the observations of
Regnault and Reiset upon the absorption of nitrogen from the air by
animals in a state of inanition ... so that this gas ... . would seem
to be intended .... to supply the place, in a certain degree, of
alimentation by the digestive organs. If one admitted this very plau-
sible hypothesis, he would have a new datum to explain the good
effects obtained by the use of the compressed air bath in cases where
there is weakness of the digestive functions through debility. (P. 28.)
C. Compressed air aids the return of the venous blood to the
heart.
Pravaz states first that compression decreases the number of
arterial pulsations: he has even seen it reduced 2/5, "especially
when a feverish state existed previously." Then he stresses the
fact that the suction "exerted by the right auricle and the thoracic
cavity" is one of the most active causes of the venous circulation,
and he adds:
The capillary system, as a result of the increase of the barometric
pressure, must empty into the veins more easily, for not only has the
peripheral action of the force which compresses this network and the
veins into which it empties become more energetic, but also the
450 Historical
tendency towards a vacuum produced in the pericardium and the
mediastinum during the inspiration, and intended to assist the concen-
tric effort of impulsion towards the heart, must be more pronounced.
(P. 52.)
The book of Pravaz ends with the discussion of the favorable
effect of compressed air in the treatment of phthisis, rickets, chlo-
rosis, anemia, deafness, chronic congestions of the nervous centers,
and different neuroses.
In explaining the numerous successes which he lists in this
connection, Pravaz gives especial emphasis to the effect of the
chemical reason of the superoxygenation of the blood, and the
greater activity thus imparted to the phenomena of metabolism.
But he likewise refers to the mechanical action, the pressure of the
compressed air. So, in speaking of the cure of coxalgia by the
compressed air bath, he says, in a work preceding the one from
which we have just quoted: 12
In compressed air, one can carry out the indicated compression of
the swelling of the hip in the most uniform and harmless manner,
because not only the articular head but also the capsule, which pro-
jects abnormally out of its adherences, is pushed inward from without.
This compression, the force of which upon the area corresponding to
the cotyloid cavity can be reckoned as twenty kilograms per atmos-
phere, must cause the absorption, at least partial, of the liquids which
have escaped, as we see in cases of dropsy and hydrocephalus, when a
more or less tight bandage is placed around the abdomen or the
skull. (P. 8.)
Further on, mentioning the case of a girl cured by compressed
air of a wryneck "due to cephalic hyperemia," he declares that the
freeing of the cerebrum is due to the mechanical pressure:
The vacuum which is caused in the jugular veins during the
inspiration and which draws thither the blood from the head and the
spine tends to be filled more rapidly in proportion to the strength of
the outer pressure; and on the other hand, the increase of this pres-
sure must provide a greater obstacle to the ebbing movement which
the expiration causes in the afferent vessels; then we cannot be sur-
prised that the capillary system of the brain and the spinal cord, in
communication with the veins subjected to a sort of suction which has
become more vigorous than in the normal state, can free itself of the
excess of blood which choked it. (P. 13.)
Pol and Watelle 13 are the first authors who have tried to explain
the symptoms of decompression, the time of which they had also
been the first to determine definitely. They are the ones who re-
ported to us .this characteristic saying of the workmen: "Pay only
when leaving."
Theories and Experiments 451
Let us note, in passing, as a sort of curiosity, the idea suggested
by these authors that "the unaccustomed density of the compressed
air would hamper walking," and that the difficulty in talking in the
cylinders, which they had observed, would also result from "this
unexpected resistance to muscular contractions instinctively gauged
by habit." (P. 250.)
Now comes the explanation of the symptoms produced by de-
compression. The physicians of Douchy attempt, according to their
expression, "to discover the meaning of the symptoms observed,
and to determine, by interpreting them, the nosologic individuality
which they characterize." Now they say:
This task is easy to accomplish, or rather it is already accom-
plished.
In fact, if we except the muscular pains, at least in the cases in
which, being isolated, and unaccompanied by any indication of a dis-
turbance of the nervous centers, they were probably produced by the
impression upon the capillaries of this system of a blood with an
excessive oxygen content;
If we also except the gastric symptoms, which have sometimes
seemed purely sympathetic, and sometimes, in our opinion, have been
caused by the very copious ingestion of the products of combustion,
it seems very clear that they have always been above all the expres-
sion of a state of congestion of the brain and the lungs.
We shall not strive to demonstrate, with symptoms at hand, this
proposition in regard to which the autopsy of Heraut admits no doubt,
and which will gain an over-abundance of evidence from the results
of a second autopsy.
Pulmonary and cerebral congestion is therefore the principal re-
sult of the compression of the air; it is its most important morbid
result, the source from which the fundamental therapeutic indications
are derived.
We purposely omit mention of the congestions of the liver, the
spleen, and the kidneys, noted in the autopsy reported above, and
which will be repeated in the following one; they were not revealed
by symptoms, except that of the kidneys which caused excessive
secretion. (P. 259.)
So the serious symptoms experienced by workmen are the con-
sequence of visceral congestions. But what can be the cause of
these congestions? The compression, they reply, as an agent of
the mechanical class; at least, that is what is clearly expressed by
the following passage:
Since, when the atmospheric pressure is much decreased, the
blood flows towards the exterior and escapes from the capillaries,
there should result from the compression of the air visceral conges-
tions, deep hyperemias. For contrary influences, opposite effects:
contraria contrariis.
452 Historical
Thence comes this conclusion, as yet wholly theoretical, that if a
constantly increasing pressure were exerted, we should see occurring
to a degree at present indeterminable intra-organic hemorrhages,
apoplexies, instead of the peripheral hemorrhages caused by the rarity
of the air. (P. 272.)
But if it is the compression itself which causes the congestions,
why is it that they display their dangerous effect only at the time
of the decompression? Here is the odd reply made by the two phy-
sicians to this objection which might seem unanswerable:
Rasori thought that congestions are invariably venous, and that is
beyond doubt when they are caused by an obstacle to the return of the
blood. But is this also true when they are the result of an arterial
afflux; would the circulatory stoppage which constitutes them be
located exclusively in the venous capillaries then also; in a word,
would the dark blood be the agent of the congestions under all circum-
stances, as the Italian physician thinks?
The observations of M. Andral do not contradict this opinion; on
the contrary, they justify it, since the consequence is that the congested
tissues, red in the first phase, which according to M. Dubois of Amiens
is only an inflammatory stage preceding congestion, are brown in the
second phase and black in the third.
Now let us admit by hypothesis that their harmful effect is due
rather to the narcotic effect of the dark blood than to the compression
resulting from an exaggerated supply, and it will follow that if the
inspiration of an excess of oxygen should arterialize the venous blood,
congestions, depending upon the quantum, should lose all or part of
their harmful power.
Well, that is exactly what happened in our miners; on the one
hand, congestion without any symptoms; on the other hand, brignt
red venous blood.
And as a counter-test, when the agent of the redness was removed
and its action destroyed or lessened to a certain degree, which took
a variable time, serious symptoms occurred which might be fulminant.
So the congestions which result from the compression of the air
do not reveal their existence as long as this compression is exerted.
The compression consequently has its corrective within it.
The decompression in a way reveals the congestions; it lets them
exert their full and complete effect; we might say that it makes them
effective instead of latent and potential.
From that, we imagine that it must appear more dangerous in
proportion to its speed, and that to make it harmless, probably one
would need only to make it very slow, much slower than it has been
at Louches most of the time. (P. 260.)
So the physicians of Douchy give to the superoxygenation of
the blood a role which is surely strange, but very important. It is
interesting to see, however, how vague an idea they had of the
conditions which in compressed air cause this superoxygenation.
Theories and Experiments 453
In fact, speaking of the inspirations of oxygen which had formerly
been attempted, they protest against any comparison between the
use of this gas and that of compressed air:
Certainly it is a very different thing to breath pure oxygen, or
even oxygenated air, and to breathe air which is merely compressed,
without any quantitative modification of its elements, air in which the
oxygen is still diluted with nitrogen in the natural proportions.
(P. 269.)
The lengthy note which A. Guerard 14 placed after the impor-
tant memoir of Pol and Watelle in the Annales d'Hygiene is only a
compilation. It contains nothing new, either from the point of view
of phenomena observed or from the point of view of physiological
explanations. Only its author stresses, more than anyone had done
up to that time, the enormous changes which the increase of pres-
sure made in the weight supported by the body. He drew up a
detailed table of them, from which, as a curiosity, we extract the
following figures:
At 1 atmosphere the weight supported varies from 15,500 to 20,600 kg
At iy2 atmosphere the weight supported varies from 23,250 to 30,400 kg
At 2 atmospheres the weight supported varies from 31,000 to 41,200 kg
At 3 atmosphere the weight supported varies from 46,500 to 60,800 kg
At 4 atmospheres the weight supported varies from 62,000 to 82,400 kg
At 5 atmospheres the weight supported varies from 77,500 to 103,000 kg
At 6 atmosphere the weight supported varies from 93,000 to 123,60ff kg
And he assumed that there were terrible extra weights, since
at 5 atmospheres they would vary from 77,500 to 100,000 kilograms!
Guerard supposes besides that, under the influence of the pres-
sure, the oxygen and the nitrogen are dissolved in the blood in
greater quantity, and that the result is an increase of interstitial
combustions, and consequent emaciation.
As to the muscular pains, he considers them as being of a rheu-
matic nature, and due to the chill which accompanies the decom-
pression.
Then, admitting as general the greater facility of movement
which Pol and Mathieu had thought they noted in some of the
workmen in compressed air, he says:
It might be that the influence exerted on walking by the atmos-
pheric pressure would be magnified by the increase of this pressure.
For the rest, he accepts the conclusions of Pol and Watelle and
those of Pravaz.
With Dr. Milliet,15 we return to observations of a purely medical
nature. In the opinion of this physician, the action of compressed
454 Historical
air is exclusively physical; he protests against the idea of a chemical
change in the respiratory acts; but, aside from this protest, he
furnishes no clear idea:
When the organs of respiration are plunged, so to speak, into a
more condensed atmosphere, the lungs will find in the same volume a
considerably greater quantity of atmospheric air; after that, they will
come in contact, at every inspiration, with a larger mass of atmos-
pheric air ... . What will be the result of this addition? This single
effect, a greater ease of operation. (P. 15.)
This reduction of rhythm in the operation of the respiratory
movements is purely physical, and in spite of the generally accepted
ideas, it is certain that no chemical modification, either an increase or
a decrease, is produced in the process of the oxidation of the blood.
The air has not been changed in its chemical composition, and the
laws which govern our organism have not ceased in their natural
action.
So, whether the atmospheric air is rarified or condensed, there is
no modification in the chemical action of respiration; there is only a
physical effect upon the performance of this function. But the
situation is very different if you change the chemical proportions of
the gases of the air.
One of the effects of the use of compressed air is the increase of
the secretions and of absorption. The nervous activity in the excretory
and absorbent organs has seemed to me to be derived from the venous
circulation, which is always more ample and more complete while
the body is being subjected to a higher pressure. (P. 16.)
In 1855, there appeared the first edition of the book which
Eugene Bertin,110 who was using the apparatuses installed at Mont-
pellier by Tabarie, devotes to the study of the therapeutic use of
compressed air. This work, as its title indicates, is of particular
interest to physicians. Moreover, the author declares in the begin-
ning of his book "that he will not discuss physiological consider-
ations." And so we shall not pause long over it.
However, he summarizes his opinions in the following words:
Compressed air, to whatever degree the compression is carried,
can be sustained without danger because of the equilibrium of pres-
sure which is established in all parts of the body, exactly as in ordi-
nary atmosphere.
Experimentation demonstrates that at a pressure carried far be-
yond the degree needed to cause all therapeutic effects, no modifi-
cations in the phenomena of life occur which might interfere with
their regularity.
It is logical to admit that since the decrease of pressure can delay
the return of the venous blood to the heart and thus promote stases
in the capillary system, an increase of pressure should, on the con-
trary, facilitate this return and dissipate these congestions.
Respiration which is carried on in compressed air, because it
Theories and Experiments 455
brings the blood in contact with a greater quantity of the two constit-
uent elements of the air in the same volume, must of necessity
decarbonize a greater quantity of blood than under ordinary condi-
tions. For the same reason, the part which the nitrogen may play in
the body should also be more completely filled. Every inspiration
therefore should have a more extensive effect in compressed air than
in ordinary atmosphere: hence the necessity of less frequent inspi-
rations to satisfy the customary needs; hence a decrease, often very
great, in the action of the pulmonary organs, and the source of a rest
which is so useful and yet so hard to secure in any other way for
organs whose action must be incessant.
Because of relations uniting respiration with the heart beats, the
slackening of the former must cause a similar change in the circu-
lation; many data, moreover, permit us to attribute to compressed air
a direct sedative effect on the circulatory system; under this double
action, the slowness of the pulse becomes a permanent condition, not
only during the continued use of compressed air baths, but even a
long time after their discontinuance ....
At the same time, the appetite increases, the digestive functions
go on regularly, and therefore good nutrition, the undoubted source
of an increase in the general strength, is assured ....
The secretions show few signs of the effect of compressed air. I
have noted a perceptible increase of the saliva while the baths were
being given. (P. 60.)
In his second edition, published in 1868, Eug. Bertin reproduces
purely and simply (p. 97) the summary which we have just quoted.
Moreover, if- we exclude the medical observations, much more
numerous than in the first edition, we find very few changes from
the original text.
The most important addition is the criticism of the opinion of
Vivenot about the slowing of the heart rate. Bertin first remarks
that he has rarely observed this decrease in the apparatus; on the
contrary, he noted it after the bath, almost always several hours
after, or even the next morning before the patient had risen. Often
it does not exist at all. Finally, it is not proportionate to the pres-
sure, he says, for then it would be enormous in caisson workers.
We saw above that Hoppe,17 in a notable work on the causes of
the death of animals killed suddenly by rarified air, had found in
their blood vessels bubbles of free air, to which, in his opinion, the
death was due. He did not fail to apply to the symptoms of sudden
decompression the observation which he had made:
If, after an animal has remained for some time in compressed air,
the pressure is suddenly lowered, the lungs will not have time to
allow the gases which have been freed in the large veins to escape.
That is why sudden deaths, without anatomical lesions, have occurred
in the coal mines of France. (P. 72.)
456 Historical
We should note that Hoppe never made direct experiments on
this point, and that he reasons only by analogy.
As to the effect of the compression itself, he says merely:
The increase of the air pressure must increase the capacity of
the blood to absorb gases; the blood will then contain more oxygen,
from which will result a greater production of heat and a decrease
of the quantity of air breathed in a given time. The observation of
Pravaz of a lessened quantity of carbonic acid excreted in compressed
air is explained by the small volume of air used in his experiments.
(P. 71.)
Dr. Frangois,18 after the account which we have quoted of the
symptoms appearing in the workmen at the bridge of Kehl, in-
quires into their cause. He first rejects the opinion of Guerard
about rheumatism, and one of the reasons he gives is that "the
muscular pains disappear spontaneously if the workmen go back
into the compressed air." The explanation which he gives of these
pains is very strange:
They are (he says) the evident result of introduction into the
tissues of compressed air, forced in by the blowing machines, and this
air blends with the cellular tissue in its innermost parts, as, for ex-
example, mercury blends with hog's lard after a careful trituration, so
that not a molecule of metal is perceptible to the naked eye.
This air, thus accumulated beyond measure in our tissues, must
seek to establish an equilibrium with the ambient atmosphere at the
time of leaving the compressed air, and the more hasty is this depar-
ture from the air chamber, the less gradual it is and the less prolonged
is the elimination, the more pronounced the pathological effects must
be, for the reason mentioned above.
He explicitly rejects, as Pol and Watelle had done, any com-
parison between superoxygenated air and compressed air:
We cannot agree that these pains are produced by the presence
of an air with a higher oxygen content, as has been suggested; in fact,
every atmosphere of compressed air contains, with all its other ele-
ments, only the same proportion of oxygen that it contains on the out-
side: it is not an excess of oxygen that is forced into the caissons,
but rather an excess of atmospheric air.
We are therefore inclined to admit that the muscular pains are
the result of a constant effect exerted upon the tissues by an excess
of atmospheric air, an irritation sometimes rising to the most acute
pain, when this air seeks too suddenly to find an equilibrium with a
less dense medium. (P. 309.)
So much for the muscular pains. As to symptoms affecting the
respiration, these are pulmonary congestions, M. Frangois says:
Theories and Experiments 457
Their method of production is easily ascertained; in fact, we know
that the increase of the pulmonary capacity is very great under the
influence of compressed air; that the cells of the respiratory organs
are considerably distended: at the time of leaving the caissons and
especially after a hasty and poorly managed decompression, a vacuum
is too quickly made in the thoracic cavity, and this vacuum must nec-
essarily be replaced by a speedy afflux of blood and the other liquids;
hence these congestions; hence also this spitting of blood, as a result
of the rupture of vessels in the pulmonary parenchyma.
Therefore one may understand that full-blooded, plethoric persons
are more subject to these affections than persons with lymphatic or
nervous temperament.
The cerebral symptoms, examples of which we have mentioned,
are also in his opinion the result of congestions. And here, M.
Franqois tries to explain why they appear exactly at the time of
decompression:
It is undeniable that these cerebral congestions, like those of the
pulmonary tissue, do not result from the same causes as congestions
attacking persons in the course of ordinary life, in which they are
produced generally by a stasis of venous blood occasioned by an
obstacle to the return of the blood; at other times, but less frequently,
they are the result of a great arterial impulse; but then there always
occurs a subsequent stasis which may become harmful when the
congested blood changes from red to dark and becomes a depressant,
that is, when it becomes less and less rich in oxygen.
Is the same thing true in congestions produced by compressed air?
Evidently not, for here there is no congestion as long as the increased
atmospheric pressure lasts; then when the workman leaves the in-
creased pressure, the excess of air contained in his body seeks to
establish an equilibrium with the outer air; this tendency operates
immoderately, as would be expected; hence, a surge of blood, but a
red blood, towards the nervous center, a surge which sometimes is
overpowering, especially if the decompression has not been made
gradually and carefully, but which up to the present has not produced
any fatal case.
In all cases, when the patient was bled, the blood issued from
the vein very red; no dark blood has been observed in bleeding.
(P. 313.)
Finally paraplegias, retention of urine, etc., would be due to
medullary congestions produced by a similar cause.
It is likewise, as we said, upon the workmen employed at the
bridge of Kehl that M. Bucquoy 19 made his observations. His work
is extremely noteworthy, especially from the point of view of
physiological explanations. ,
He first discusses the increase in the quantity of oxygen con-
tained by the blood. But the hypothesis which might have ap-
458 Historical
peared very simple to Pravaz becomes strangely complicated after
the work of M. Fernet. (See page 249.) M. Bucquoy, who dwells
at length on the difference established by this physicist between
the oxygen chemically combined in the corpuscles and the oxygen
dissolved in the serum, says also:
It is to the oxygen in simple solution that the changes in hematosis
observed in compressed air are due.
In fact, the blood corpuscles in compressed air do not absorb a
greater proportion of oxygen than in the open air, because this pro-
portion has been shown to be independent of the pressure.
On the other hand, the expenditure of oxygen which the blood
must make for the benefit of the respiratory combustions is as great
in compressed air as in open air, because these combustions are no
less active there than under ordinary atmospheric pressure.
If then, in compressed air, the blood corpuscles supplied alone
and without compensation all the oxygen necessary for the combus-
tions, they would lose, as at ordinary pressure, a quantity of oxygen
sufficient to cause their arterial color to disappear, and when they
left the general capillaries, they would have the color of venous blood.
Now this is not the case; the corpuscles of venous blood are bright red
in the man who is subjected to compressed air.
This fact, important from the physiological point of view, can be
explained in only two ways:
Either the blood corpuscles supply for the respiratory combustions
under compressed air too small a portion of oxygen for their red color
to be perceptibly altered; in this case, the complement of oxygen
necessary for the combustions is taken directly from the portion of
this gas which is in simple solution in the serum, the quantity of
which, however, increases with the pressure.
Or the corpuscles furnish all the oxygen necessary for the com-
bustions; in this second case, we are obliged to admit that they take
it from the serum as they lose it, since their color is hardly altered;
this hypothesis is the more probable.
However it may be, the portion of oxygen dissolved in the serum
plays directly or indirectly an important part in the phenomena of
hematosis which go on under pressures greater than that of the atmos-
phere. It is this portion of oxygen which alone can explain the redness
of the venous blood always found by MM. Pol and Watelle, and by
M. Frangois too. It is wrong, therefore, that this portion of oxygen
absorbed should now be neglected and that variations in pressure
should be considered immaterial in regard to hematosis. (P. 50.)
After this noteworthy page, I am sorry to find the adoption,
timid, it is true, and full of reservations, of the unsound theory of
the physical compression of the outer tissues, and of the conse-
quent ebbing of the blood into the interior of the body. Here is the
way, very original I admit, in which M. Bucquoy words it:
Theories and Experiments 459
The increase in pressure of the ambient medium produces its
maximum effect upon the tissues of the periphery. These tissues be-
come more compact, but they resist the outer pressure to a certain
degree, and neutralize a fraction of it. The remaining pressure com-
presses the layers lying below the first ones, but it meets a new
resistance from them which decreases its intensity still more, and so
on. In proportion as one goes from the surface towards the central
parts, the tissues are less and less compacted, and the pressures more
and more weakened. But the blood contained in the superficial tissues
transmits the outer pressure to the whole mass of the blood, in all
directions, to all depths, and almost equally. Consequently, in all parts
of the body, the blood exerts against the walls of its vessels, from
within outwards, and tending to expand them, a pressure almost equal
to the pressure it sustains from without.
To resist this expansion of the vessels, each tissue has its own
resistance and the fraction of outer pressure which has penetrated as
far as that through the more superficial layers. The result is that the
different tissues resist this expansion of the vessels very unequally,
and that the deeper the tissues lie the greater is the expansion, because
the outer pressure transmitted to the tissues by the tissues decreases
with the depth. Consequently: expansion of the vessels in the deep
tissues, where the pressure coming from the exterior is weak; decrease
of the diameter of the vessels in the superficial layers where the outer
pressure is strong; all that in a suitable measure so that equilibrium
may be established everywhere. At each new increase of pressure, a
similar effect is produced; a new distribution of blood and a new
equilibrium are established. The total effect is a greater mass of blood
in the tissues and the deep-lying organs; in a word, the visceral con-
gestions and the hyperemias, which all the authors mention, appear.
(P. 52.)
But M. Bucquoy finds solid ground again when he speaks of
the painful effects of decompression. He does not have much
trouble in managing the theories of Pol and Watelle on the slow
effects of superoxygenation of the blood, and of Guerard on the
rheumatic nature of the pains. Considering the question as a
physicist, he says:
If one enters compressed air, the oxygen, carbonic acid, and nitro-
gen, held in simple solution in the blood, must increase with the pres-
sure; and if the compression has lasted long enough, Dalton's Law
requires that the quantity of each of these gases absorbed by the
blood should be proportional to its pressure in the compressed air
which one is breathing. Under ordinary conditions, the carbonic acid
and nitrogen of the blood are not drawn in with the air inspired; they
are engendered by the physical phenomena of life. Because of their
origin, these two gases no doubt do not follow Dalton's Law strictly,
but their ponderable quantity in the blood necessarily varies in the
direction indicated by this law.
That being granted, what must happen when one leaves the com-
pressed air apparatus?
460 Historical
During and after the decompression, all the gases dissolved in
excess in the blood, because of the compression of the air, will tend
to escape from the blood with a force the amount of which will be
greater in proportion to the increase in the pressure undergone, the
stay in compressed air being equal. That is a necessary result of the
laws of physics dealing with the solution of gases in liquids, and we
have a common and frequent example of it in the speed and force
with which the carbonic acid escapes from a charged water when
the cork is removed from the bottle containing it. (P. 58.) ....
The particles of gas which have regained the aeriform state all
through the blood system remain mechanically blended with the
liquid molecules which held them in solution before; it follows that the
blood becomes an expansible mixture which constantly struggles to
distend these vessels and to increase in volume. The ultimate result
is a general and more or less important turgescence of the blood
vessels and a more or less threatening imminence of hemorrhages.
And as the gases dissolved in excess separate from the humors as they
do from the blood, a general tendency to emphysema will result.
Let us now attribute to the expansive power of the liberated gases
a sufficient intensity, and it does not need to be great, if it is favored
by individual peculiarities, and then the threat of hemorrhage and
the tendency to emphysema will become facts. We shall have all the
cases of hemorrhage and emphysema observed in ascents of lofty
mountains, or in balloon journeys, or in compressed air apparatuses.
(P. 59.)
Supported by this excellent basis of reasoning, M. Bucquoy
easily explains the emphysemas observed at Douchy, the hemor-
rhages, and the muscular and articular pains, in regard to which he
quotes the following very interesting observation:
One day when I was observing a workman who was having severe
pain in one knee, I saw the dry cupping-glasses placed around the
articulation falling off one after the other, although they had been
carefully applied by the orderly, a very skillful man. They were
replaced several times and remained in place only a certain time; the
patient was then considerably relieved. The elimination of the free
gases explains both the falling of the first cupping-glasses and the
prompt disappearance of the pain through their repeated application.
(P. 62.)
M. Bucquoy finally with good reason advises the engineers to
take all precautions necessary to make the decompression suffi-
ciently slow.
We reported above (page 379) the story of the patient of M.
Hermel,20 who was seized by paralysis when he was leaving the
caissons of the bridge piers of the Scorff*, near Lorient. The author
attempted, when he summarized the preceding observations, to
explain the symptoms noted; we shall see that he is not very suc-
cessful in his attempts.
Theories and Experiments 461
He first dwells at great length on the confinement to which the
laborers working in the caissons are subjected. The carbonic acid
which is produced there must, in his opinion, play a great part,
and recalling the tinglings and the burning of the skin described
by Herpin (of Metz) he thinks:
That this phenomenon might very well be the cause of the burning
and itching of which the workmen complain and which MM. Pol,
Mathieu, and Frangois have noted, which the workmen call their fleas.
Likewise, the effects of the bath of carbonic acid which accelerates
the circulation may give us the reason for the divergence of opinions
which we have reported between MM. Pol, Mathieu, and Blavier, on
the one hand, (the first two having observed a slowing down of the
circulation in compressed air, the third having noticed no difference
in three persons) and on the other hand, M. Franqois, who noted a
constant acceleration of the circulation. (Vol. XVI, p. 445.)
As to the redness of the venous blood, observed by Pol and
Watelle, he refuses to accept their shrewd explanation. He repeats
with Francois that "it is not an excess of oxygen which is sent into
the caissons but an excess of atmospheric air." He even goes
further:
As we have proved, the oxygen of the caissons was considerably
diminished by the respiratory absorption and combustion; since the
carbonic acid is a hindrance to hematosis, how could the venous
blood be oxygenated? We must seek some other reason for the
redness of the blood. The conditions of the medium which we are
discussing give reason to assume the formation of carbon monoxide,
which would explain this phenomenon. (P. 447.)
This carbon monoxide would be produced, according to our
homeopathist, by respiration in air with a low oxygen content.
Such is the cause of the symptoms attacking the workmen:
Since the authors saw these symptoms appear only after decom-
pression, they have attributed them all to this transition.
He then reaches the study of decompression; and he compares
what takes place in workmen with the effects of ascent into the
lofty regions of the atmosphere. There is a great difference, how-
ever, he says, namely:
As it is the normal pressure of the air which keeps the fluids in
the vessels, it is rare that the hemorrhages which are frequent in
ascents appear when the men leave the caissons. (Vol. XVII, p. 37.)
Besides, the effects are more serious than those of ascent because
the compression is greater, because the decompression is more
rapid, because it acts upon men in a manifestly morbid condition,
462 Historical
and because this sort of rarefaction takes place in a confined air
mingled with harmful gases.
In regard to the muscular pains, he rejects the explanation of
Pol and Watelle:
Because we did not find that the blood absorbed a greater pro-
portion of oxygen than normally. (P. 112.)
But we admit with Francois that the compression of the air forces
a certain quantity of air into the tissues. This fact is demonstrated by
the cases of subcutaneous emphysema. (P. 114.)
As to the serious symptoms, they are, in the opinion of M.
Hermel, pulmonary, medullary, and cerebral congestions, which
he explains by the rebound produced by decompression; moreover:
The decompression in itself (he says) does not produce all the
symptoms noted; the compression of the air in the caissons and the
harmful environment have much to do with it. (P. 203.)
The work of M. Foley 21 is certainly the most original from the
standpoint of theory of all those we have already found and sum-
marized. Reading it is very stimulating, though not very easy; in
it, in fact, are found not only the account and the explanation of
the symptoms which attack the workmen in caissons, but also the
theory of the respiration of birds in the lofty regions of the air, the
operation of the swimming bladder in fishes, etc. Setting aside
these questions, which concern us only indirectly, we find M. Foley
trying to cast light on the inner cause of the symptoms which he
has observed by a study, which is hard to understand, of metabo-
lism, hematosis, and the physiology of the three nervous systems
by means of which "man (plant, animal and soul) governs his
multiple being."
An example will indicate the nature of these considerations and
their conclusions. The author remarks that engineers go a long
time before feeling the ill effects of compressed air:
That is because (he says) usually the former (engineers) nourish
their spinal cord and consequently stimulate their whole being with
memories, retained sensations, and because after that, to crush their
senses is to favor (so to speak) their ordinary mode of life.
On the other hand, the second (workmen), forced to live and
work from day to day, to fashion and expend stimulation from hour
to hour (because they have never had time to accustom the primary
source of our organic activity to retained impressions), can nourish
their spines only with the materials of atmospheric contacts, always
real, always positive, always immediate: the very materials which
the excessive pressure prevents them from collecting. (P. 24.)
Theories and Experiments 463
I confess that I think I must give up the task of summarizing in
a definite and intelligible statement the theories of M. Foley. Here
are a few quotations which I try to coordinate so as to cast a
little light on these obscurities of thought and style:
As soon as the workmen are in the compressed air, their blood
becomes superoxygenated and their circulation tends toward its mini-
mum. At the same time, their nervous reserve, already so low, ....
falls still more.
However they work, or in other words, their muscles and their
different mechanical organs, while being nourished by the blood, re-
quire stimulation from the spinal cord and plastic energy from their
controlling ganglia; from this triple compound of brain, spinal, and
sympathetic pulp; from this triple mixture of coordinating, vegetative,
and stimulating substances, the sympathetic chain first decides the
course of the blood, then regularizes it, and finally transforms it into
human flesh.
How do the mechanical and metabolic governors, thus questioned,
reply to their subjects?
But the spinal cord which no longer produces enough stimulation
refuses to give any, perhaps even demands to have some back from
the ganglia or plexus of the sympathetic chain! In their turn then,
they refuse to give any to their subjects, which nevertheless continue
to work, become empty of blood, then deteriorate, and finally are
unable to continue to operate. (P. 27.)
So much for the phenomena caused by compression; now let us
turn to the decompression:
We shall have the inverse of what the compression caused. (P. 44.)
Little by little, the blunted senses of the caisson- worker revive;
little by little they send to the spinal cord more complete sensations;
little by little the apparatus of the spinal cord regains its power.
Little by little, it sends to the parts of the sympathetic chain, upon
which have been made such strong demands, the stimulation which
they need for their own recovery; and little by little, but in the final
step, these controlling nerves give the order which will send the
restorative tide to the muscles or other exhausted organs.
Finally this command is dispatched. It leaves like a thunderbolt.
But generally too obedient to the principle (the reaction must equal
the action), it almost always causes an arterial congestion, the degree
and speed of which are proportional to its delay. (P. 28) . . .
In summary, for the caisson-worker who has returned to open
air, we need to fear only too strong a nervoso-circulatofy reaction, a
shock to the circulation in this excessively violent change. (P. 45.)
That is what M. Foley calls by the name of "post-caisson con-
gestion."
"Thus," still according to M. Foley, "we have all the necessary
keys to the understanding of the different morbid phenomena which
may arise when one has left compressed air." (P. 29.)
464 Historical
Here, for example, is the key to the discharge of blood which
occurs rather frequently from the nose or mouth:
The mucous membrane, almost bloodless as long as the compressed
air acts upon it, fills with blood as soon as the tension ceases, ruptures
if it is too thin .... then, momentarily surprised, it recovers its
normal thickness after a few painful oscillations. (P. 30.)
And now for the sensations of heat in the skin, and for the
"painful, burning, intolerable itching, which forces one to scratch
himself with both hands with impatience, uneasiness, fury, or
delirium, which the workmen call fleas":
As soon as one enters the caissons, he is flattened; the arteries
diminish in caliber, and there is abundant perspiration. By all these
effects our skin empties and withers.
As soon as one leaves, on the contrary, merely through the me-
chanical power of its elastic fibers, this envelope expands. Unfortu-
nately the retractility of their yellow coats keeps our nutritive vessels
at their minimum diameter. The result is that a sort of vacuum forms
around them.
Matters being thus situated, when the reaction begins, or in other
words, when the blood waves become strong again, our arteries, which
previously were isolated, yield easily, regain their former diameter,
and even increase it. At the same time, our innumerable cutaneous
papillae are considerably swollen by a superoxygenated blood. Then
within the thickness of the skin the nerve meshes which are inter-
woven with our nutritive vessels, suddenly tugged about inordinately,
cause cruel and lacerating pains, whereas on the surface of the skin
any contact causes both itching and burning. It is all these simulta-
neous pains that cause the "fleas." (P. 33.)
Finally, the symptoms which attack "the muscles, then their
synovial auxiliaries, aponeurotic or articular," are explained in the
same way; they are tumefactions, as we have already seen
(page 377) :
Are these swellings of a gaseous, hemorrhagic, or rheumatic
nature, as has been stated? No!
The recompression which always dispels them immediately, the
absence of crepitation, of rale, of any coloration under the skin, and
of peregrination, and finally the excessive richness of the blood, which
excludes any idea of excess fibrin, or, in other words, of an inflamma-
tory malady, do not allow us to doubt. These are simply arterial con-
gestions without extravasation. (P. 35.)
M. Foley does not hesitate to predict the brightest future for
treatment by compressed air:
Make (he says) a sedan chair closing hermetically .... Attach
to it a safety valve, a blower, and a manometer: in a word, arrange
Theories and Experiments 465
everything so that in this little chamber the air pressure may reach
2.5 atmospheres, at the most.
And certainly you will possess a piece of furniture which will
allow you to relieve many asthmatic old men, to save many children
attacked by croup, and also to cure many adults afflicted with conges-
tional, toxicohemic diseases. (P. 135.)
Without discussing the value of these hopes, we must call the
attention of the "realizers," as M. Foley calls them, to the fact that
the construction of the apparatuses is considerably more compli-
cated and more expensive than he seems to think.
M. Caffe 22 was commissioned by the Societe Medicale d'fimula-
tion to investigate the work of M. Foley. He took advantage of
the opportunity to study the effect of compressed air in his turn.
He first accepts the ideas of Dr. Frangois about the mechanical
effect of compressed air and about the "amalgamating" of the air
and the tissues; he summarizes them in the following words:
M. Frangois attributes the muscular and arthritic pains to the
penetration into the tissues of compressed air, which becomes a cause
of irritation, designated as "caisson pain"; abscesses sometimes follow.
An experiment seems to confirm the opinion of M. Frangois; at the
time when the caissons were being sunk, when the oak timbers, which
had been subjected to the compressed air, were removed from within
the caissons, these beams, when plunged into water, gave off consider-
able quantities of air bubbles.
The danger of cerebral congestions is likewise referred to the
exit from the lock-chamber; when the blood has been freed from the
pressure of the compressed air, it tends to establish an equilibrium
with the outer air; it therefore is urged towards the nervous centers,
brain, and spinal cord; even the urinary bladder loses its contractility.
(Page 2.)
Then after reporting the observations and theories of M. Foley,
he declares himself a very ardent partisan of his "sedan chair," and
cries out enthusiastically:
We shall then possess an ingenious apparatus which will become a
valuable therapeutic resource for the solace and prolongation of the
life of many catarrhal and asthmatic old men, and for relieving pains
so hard to witness and to endure in adults afflicted with angina
pectoris, who turn blue and suffocate while seeking the air which
eludes them.
Without any effort of the imagination, but proceeding with the
logic of data and reasoning, we can picture the hope of saving from
imminent death the victims of the last stages of croup. The compressed
air will depress and flatten the false membranes, and will restore
free passage of the air in the respiratory tracts. Cerebral congestions
and predispositions to apoplexy will be warded off as long as the nerve
influx controls the circulation; perhaps* we may even hope that typhus,
466 Historical
glanders, and all diseases of a blood-poisoning nature will be cured,
or at least considerably shortened in their course and checked in their
severity by respiration in compressed air, which arterializes and
oxygenates the blood without any effort; experiments can easily be
carried out on animals.
The venom of the viper, the virus of the rabies, of smallpox, etc.
perhaps will be neutralized locally some day, since they will encounter
in compressed air a very rich, essentially vital blood, which will
consequently refuse to serve as a vehicle for the poison, and they will
therefore be annihilated on the spot. What physician does not know
that contagious or transmissible diseases become so only when they
encounter persons who are predisposed, and who therefore form a
suitable breeding-ground for them? (P. 7.)
The English authors, Babington and Cuthbert,-3 who were wit-
nesses of the accidents at the bridge of Londonderry, tried like all
their predecessors to explain them. They too were surprised to
see that these symptoms occur exclusively in the phase of decom-
pression:
The idea of a dangerous element in compressed air must be aban-
doned, because the workmen felt no ill effects during the period in
the cylinder, which lasted 3 or 4 hours. All cases of serious sickness
occurred when an excess pressure was removed more or less rapidly.
It seems reasonable, in the absence of any other cause, to suppose that
the sudden transition from compressed air to open air occasions all
these serious symptoms.
But why does this change attack the nervous system? The brain
and the spinal cord, encased in their bony cavities, and having their
vessels protected thereby, cannot yield to the atmospheric pressure as
easily as the more elastic parts. So when the workman is under an
excessive pressure, if this pressure is removed from the surface, the
brain cannot adapt itself to this change as rapidly as the other organs;
the excess pressure on the brain and the spinal cord must be removed
through the narrow passages by which the blood leaves these organs.
The bony channels in which the blood vessels lie make this escape
more difficult, and the excess pressure presses upon the delicate nerv-
ous parts rupturing the little vessels, and producing the series of
dangerous symptoms which we have reported. (P. 318.)
Dr. Sandahl -4 is very definite in his explanations. In his opin-
ion, the physiological modifications observed are principally the
result of an increase in the quantity of oxygen contained in the
blood. The mechanical effect of the compression is exerted only
through the medium, so to speak, of the dissolved gases:
The greater oxygen content of the compressed air naturally acts
more energetically upon diseased lungs than upon healthy lungs. Let
us assume that a healthy man makes 20 inspirations per minute, eacn
absorbing 30 cubic inches of air; if his lungs become diseased, and
Theories and Experiments 467
then inspire only 20 cubic inches, he will have to make 30 respirations
per minute to bring the same quantity of oxygen into his body. If
he is given air with a half-atmosphere of compression, his lungs will
make only 20 respirations, because 20 cubic inches of this compressed
air will be equivalent to 30 of ordinary air.
If the total mass of blood in a healthy man passes through the
lungs in 4 minutes and absorbs a certain quantity of oxygen there,
in case the lungs are shrunk by disease, it will have to pass through
more quickly to absorb the same quantity of oxygen, and for this
reason there is a necessary increase in the pulse rate. If compression
has made the oxygen content of the air greater in the same volume,
the blood will obtain more oxygen from it, and the circulation will not
need to be so rapid ....
An essential action of compressed air is its effect upon the free
gases contained in the blood. The presence of these gases permits
the mass of the blood to be compressed by the air, so that the vessels
contract. This effect at first must be produced particularly upon the
vessels on the surface of the body. The capillaries of the skin and the
lungs will therefore contract ....
The increased production of carbonic acid in compressed air needs
to be demonstrated by new researches ....
Since the compression brings more oxygen into the blood, we
might expect to see the temperature of the body rise. But that did not
take place under observations made with the greatest care .... More-
over, the slackening of the respiration and the circulation should
compensate for the greater quantity of oxygen contained in the blood.
A discussion of the perspiration, urine, and nutrition follows,
from which no definite conclusion is drawn.
Tutschek 25 makes a more concise statement of similar opinions.
In his opinion, the action of compressed air has two factors:
The increased mechanical pressure, which modifies the flow of
the blood; the increased oxygen content of the blood, which exerts a
great influence upon the metabolism.
We now come to the works of Rudolph von Vivenot.26 The part
describing the changes in the respiratory rhythm as a result of the
stay in compressed air has been reported in the preceding chapter.
(See page 420.) As to the explanation of the increase in the pul-
monary capacity, Vivenot finds it in the following theory:
Although the increased pressure is exerted equally over all parts
of the surface of the body, the effect produced by this pressure is by
no means equal everywhere, because of differences in texture, con-
sistency, and position of the different organs.
The pulmonary tissue, which is delicate and elastic and yields
easily, will resist the increased pressure less at the base of the lungs,
where it rests only on the intestines, which are very compressible,
than at the thoracic walls, which are formed of firmer and more com-
468 Historical
pact tissues. That explains the increase in the vertical diameter of
the lungs and their displacement downward.
The modifications which the action of compressed air can cause
in the gaseous exchanges of respiration were studied by Vivenot
with a profusion of detail; the paramount importance of this phase
of the question compels us to quote here a great part of his memoir
of 1865:
As a basis of observations, it was necessary to determine the
quantity of carbonic acid exhaled in respiration, in order to see
whether the quantity of oxygen absorbed and the quantity of oxygen
consumed differ as a result of the compressed air.
A priori, one might expect an increase in the absolute and relative
quantities of oxygen absorbed; in the absolute quantity, because of
the increase of the pressure exerted upon the lungs, and also because
of the previously mentioned increase of the pulmonary capacity; in
the relative quantity, because the number of respirations is decreased,
and because it has been proved that the carbonic acid exhaled, and
sometimes also the oxygen absorbed, are in inverse proportion to the
frequency of the respiration. (Vierordt)
Vivenot then describes the spirometer which he used, and into
which "was exhaled the air coming from an expiration as strong as
possible, but made without great effort":
If we are to have any confidence in the result, the expiration, as
previous attempts have proved to us, must always be made in almost
identical circumstances. That is why the greatest precautions have
been taken, and experiments were made on inspirations as deep as
possible, made at intervals of one hour and under absolutely similar
conditions.
In my case, the volume of air was on the average 3,700 cc. The
duration of the respiration was from 15 to 18 seconds. The first test
was made one hour before entering the compressed air, that is, at
eight o'clock in the morning; the figures obtained at that time are not
important, since they were to serve only as a point of departure for
the experiment. The second test was made at nine o'clock, imme-
diately before entering the pneumatic apparatus; the third at ten
o'clock, under the influence of compressed air, after one hour of
compression; the fourth at eleven o'clock, at normal pressure, imme-
diately after leaving the apparatus; the fifth and the sixth at noon
and one o'clock, also at ordinary pressure.
Observations made in this way, daily, from August 26 to Septem-
ber 13 inclusive, gave the following figures, as quantities of carbonic
acid expressed in grams, contained in each expiration, and correspond-
ing quantities of carbon exhaled.
Theories and Experiments
469
Observer,
Vivenot
Under normal
pressure
Under
increased
pressure
10
o'clock
Under normal pressure
8 I 9
o'clock 1 o'clock
11 1 11
o'clock 1 Noon 1 o'clock
Quantity of car-
bonic acid con-
tained in one
expiration ex-
pressed in grams
Quantity of car-
bon in one expir-
ation expressed
in grams
0.1983
0.05408
0.2236
0.06098
0.2676
0.07298
0.2183
0.05954
0.2177
0.05937
0.2106
0.05744
This result evidently proves that one expiration in compressed
air contains from 0.0440 to 0.0570 grams, on the average 0.050 grams,
that is, 1/4.352 of carbonic acid more than at normal pressure.
The figures obtained for normal pressure (with the exception of
the observation made at eight o'clock), the average of which is 0.2176
grams, show remarkable agreement; however, we cannot disregard a
slight progressive decrease of carbonic acid from eleven o'clock, that
is, after return to normal pressure, until noon or one o'clock. The
maximum quantity of carbonic acid found in my case under normal
pressure rose to 0.2890, and in compressed air to 0.3215 grams.
The data obtained from other persons gave similar results. In
M. H . . . t, an expiration of 3,000 cc. under ordinary pressure con-
tained an average of 0.1305 grams of carbonic acid, but in compressed
air 0.1735, with an excess of 0.0430 grams, that is, 1/4.04 of the total
and normal quantity of carbonic acid. In Mile. B., a single experiment
made under normal pressure gave 0.138 grams for 3,000 cc. of air
expired at normal pressure, and in compressed air 0.170 of carbonic
acid, that is, an increase of 0.0320, or 1/4.31.
Starting with the idea that at the beginning of the stay in com-
pressed air there was perhaps a greater quantity of oxygen absorbed
than towards the end of the stay, as if the blood was saturated with
oxygen, Dr. Lange made experiments upon himself, and modified my
own method of experimentation. He determined the content of car-
bonic acid in his respiration immediately before the treatment, then
he made another test after half an hour in the compressed air, that
is, when the pressure was reaching its maximum, then after an hour
of the continuous effect of this maximum pressure, that is, after a
stay of an hour and a half in compressed air. For a quantity of 3950
cc. of expired air, he obtained the following results:
Observer, I
Lange
Quantity of carbonic acid
contained in one expiration |
expressed in grams.
Quantity of carbon in one
expiration, expressed in
grams.
Under increased pressure
Under normal I On reaching I After an hour"
pressure I maximum pres- I of maximum
I sure (after a I pressure (that
I half-hour). I is, after VA hrs.]
0.2506
0.06827
0.2959
0.08070
0.2211
0.06300
470 Historical
Here also therefore, on reaching the maximum pressure, after a
half-hour in compressed air, there is an increase of the quantity of
carbonic acid exhaled, similar to that observed in me. This increase
was 0.0453 grams, that is, 1/5.53. The absolute maximum in Dr.
Lange, at normal pressure, was 0.3770 grams, and in compressed air
0.4345 grams. But we find here, after an hour of maximum pressure
a decrease of 0.0295 grams in the carbonic acid exhaled.
However the figure obtained in the last place is doubtful, as was
evidenced by tests made later, and that is explained by the fact that a
part of the expired air was lost, because the rubber tubes had not
been hermetically closed. Tests made afterwards by Dr. Lange gave
the following figures, as the total quantity of carbonic acid exhaled
in two ordinary expirations (of about 3000 to 4000 cubic centimeters)
and also as the quantity of carbon eliminated:
Observer Lange
At normal
pressure
On reaching maxi-
mum pressure
(after a half hour)
After an hour
at maximum
pressure (after
V,A hours)
Carbonic acid | 0.2460 gm. j 0.2910 gm. | 0.2920 gm.
Carbon | 0.06709 gm. 1 0.07936 gm. 1 0.07964 gm.
Which agrees with the results which I had obtained myself as
increase in the quantity of carbonic acid exhaled in compressed air.
If now I compare the figures obtained from several persons, I find
as the excess of the carbonic acid exhaled in compressed air, in com-
parison with the total quantity:
1
In myself _ =22.99%
4.35
1
In M. H . . . t =24.75%
4.04
1
In Mile. B. : =23 20%
4.31
In Dr. Lange . = 18.08%
5.53
1
Average =22.26%
4.50
We should note here that the excess of carbonic acid expired in
compressed air cannot be attributed to an increase in the quantity of
carbonic acid which might have been contained in the pneumatic
apparatus. A test of the air in the apparatus made by Dr. Lange after
three persons had stayed there for two hours gave as an average of
4 experiments on 3,500 cc. of air 0.0391 grams of carbonic acid. The
air of the waiting-room, where the spirometer was placed and where
the tests described above of the carbonic acid expired under normal
pressure were made, likewise gave, as an average of 4 tests on 3,500
cc. of air, 0.0392 grams of carbonic acid, that is, exactly the same
quantity.
Theories and Experiments 471
So it is proved, in the opinion of Vivenot, that in one expiration
there is more carbonic acid in compressed air than at normal pres-
sure. But on the other hand, the respiratory capacity is greater
in the first case than in the second. Is there a proportion between
these two increases, and can one perhaps be considered as the
result of the other? Vivenot replies to this question as follows:
If we compare the proportions of the quantities of carbonic acid
exhaled under normal pressure and in compressed air and the respec-
tive proportions of increase of the pulmonary capacity, we find:
Respiratory capacity Quantities of carbonic acid
I produced
I In normal I In com- I In normal | In compressed
air I pressed airl air air
In myself | 3425 cc. | 3533 cc.
In Dr. Lange | 3950 cc. | 4083 cc
0.2176 gm.
0.2505 gm.
0.2676 gm.
0.2959 gm.
On the average j 3687.5 cc. [ 3809.5 cc. j 0.23410 gm. | 0.28175
An increase of 1 122.0 cc. j 0.04765 gm.
Or, representing by 1 the values corresponding to normal proportions
I 1
In myself
In Dr. Lange
1 : 1 +
31.7
1 +
4.35
1 I 1
1 : 1+ I 1 : H
29.7 I . 5.53
111 1
On the average „_ 1 : 1H 1 : 1 +
| 30.80 j 4^91
So, while the increase of the pulmonary capacity in compressed
air rises to 1/30.80, the quantity of carbonic acid exhaled has risen
1/4.91. The ratio of the increases is therefore about 1:6. If I calcu-
late what the quantity of carbonic acid exhaled would be, if the
increase observed in the compressed air was proportional to the
increase of the pulmonary capacity, I find the proportion 3687.5 cc:
3809.5 cc. = 0.23410 gm. : x, hence x = 0.24197 gm. The increase cal-
culated in this case is 0.00787 instead of 0.04765 gm. which the experi-
ment gives.
This considerable difference between the calculation and the
experiment shows clearly that the increase in the quantity of carbonic
acid exhaled in compressed air is not proportional to the increase in
pulmonary capacity, which can have only a small share in causing this
increase. It would therefore seem permissible to state that the increase
in the quantity of carbonic acid exhaled would be produced by the
compression itself, acting partly according to Dalton's Law and caus-
ing a greater absorption of oxygen, under the direct influence of the
compression on the one hand, and of the fact that the compressed air
itself contains 3/7 more oxygen in the same volume.
A calculation still had to be made of the total increase in the
carbonic acid produced in a given time. To do this, Vivenot in his
calculation takes into account both the number of respirations
472
Historical
which he makes in one minute, and the quantity of carbonic acid
contained in one expiration. He explains his method of procedure
as follows:
The air exhaled by myself in one expiration contained, as was
said above, 0.2176 grams under normal pressure, and 0.2676 grams of
carbonic acid in compressed air. Now since at the time when the
analyses were made (from August 26 to September 13) the average
of my respirations was 4.15 in normal air and 3.76 per minute in
compressed air, we can draw the following conclusion from this series
of experiments:
Quantity of carbonic
acid exhaled, expressed
in grams
Quantity of carbon
consumed, expressed
in grams
I Normal | Compressed I Normal | Compressed
I pressure | Air pressure air
In one minute
In one hour __
In 24 hours __
0.903040 | 1.006176 |
54.18240 | 60.37086 |
1300.37760 | 1449.49350 I
0.24628 | 0.27441
14.7770 | 16.4647
354.6480 | 395.1528
If we compare the figures obtained for normal air with those
given by the most trustworthy authors, we find that the quantity of
carbonic acid exhaled in one hour by persons from 20 to 28 years old
has been estimated by Andral and Gavarret at 44.55 grams on
the average and at 51.7 grams at the maximum, and by Valentin on
the average at 39.146. Reduced to carbon, these figures, in the calcu-
lation of Andral and Gavarret, correspond to an average quantity per
hour of 14.1 grams, and in that of Valentin, to 10.665 grams. Dumas
specifies 10 grams as being the probable average consumption of
carbon per hour, and 15 grams for men of exceptional strength.
We see by this that figures obtained for myself at normal pressure,
although my constitution is not very robust, correspond to the highest
figures obtained by the authors, but that the results obtained in com-
pressed air still exceed these quantities considerably. The calculation
made for a stay of twenty-four hours in compressed air gives only an
ideal result, because the stay in reality lasted only two hours per day,
and therefore in this case one should take only the results of com-
pressed air for two hours and add to them those of normal air for the
22 hours remaining. When we make the calculation in this way, we
find as the real quantity of carbonic acid exhaled in 24 hours, after a
daily treatment of two hours in compressed air, 1312.7539 grams, and
as the corresponding quantity of carbon consumed during the same
time 358.0234 grams. Whence it follows that even after this reduction
the production of carbonic acid found by me still considerably exceeds
that found by other observers under normal conditions.
The explanation of the high figures which I obtained at norm.al
pressure lies in the fact that the analyses of the expired air could not
be made at the time of the first treatments for lack of suitable appara-
tuses and reagents, and were made only after I had already taken
more than a hundred treatments in compressed air. Whence it follows
that in the figures obtained upon myself at normal pressure the effect
of a prolonged use of compressed air is already a factor, that is, an
Theories and Experiments 473
increase in the quantity of carbonic acid; and analyses made before
the beginning of my series of compressed air treatments would cer-
tainly have given a production of carbonic acid corresponding
perfectly with that of the authors, that is, a smaller quantity.
The result then establishes indubitably as a -fact that the direct
effect of the compression of the air as well as the delayed effect of a
daily two-hour treatment in compressed air, repeated for a certain
time, produces a greater exhalation of carbonic acid, and consequently
also an increase in the quantity of oxygen absorbed.
From this increase in the quantity of oxygen absorbed, which
Vivenot considers proved, he draws general conclusions of the
greatest importance:
Two facts which agree perfectly with what precedes are:
1. The greater need of nourishment which is shown as an effect
of the compressed air by a noticeable increase of appetite, which I
noted in myself and in others, and which is observed especially and
without exception in laborers working in compressed air; 2. the very
considerable increase in the urinary secretion, observed again in my-
self during this series of experiments and in several other persons,
and evidenced especially in the first treatments with compressed air.
Therefore there is produced in the body a greater exchange of
materials, and that also explains apparently contradictory results,
observed by different authors.
There is an increase in the weight of the body, noted by several
authors as a result of the stay in compressed air: for instance, J. Lange
(of Utersen), who says he observed a weight increase of 5 kilograms
in thirty-eight days (from 58 to 63 kilograms) in one person, and of
5 kilograms in 21 days in another. I can confirm this observation by
what I noted in myself; for my weight had increased in four months
(from April 30 to September 1) 3% pounds (from 127.5 to 130 pounds),
which is all the more conclusive because it was in the middle of the
warm season when, as is well known, the weight of the body usually
decreases.
But on the other hand, there is one fact which cannot be disputed
either, and that is the considerable decrease in weight of laborers
working under a pressure of three to four atmospheres (in coal mines
or in the construction of bridges). Sandahl has observed the same
fact as a result of the therapeutic use of compressed air, so that this
treatment has already been advised rather frequently as a means of
combating obesity.
The apparent contradiction of these effects resulting from the
increase of the air pressure, is explained by considering the connection
between the need, the supply of materials, and the combustion. The
need of increased nourishment is felt. If then the increase in appetite
and the possibility of getting more food can not only counterbalance
but even exceed the increased combustion of the materials of the
blood (which will be the case with only a slight increase in pressure
and relatively short daily treatments), an increase in the body weight
will necessarily result. But if in the case of a combustion of carbon
474 Historical
as great as that produced in laborers working six to eight hours a
day under a pressure of three to four atmospheres, the replacement
of the materials consumed cannot be made completely, combustion
will necessarily take place at the expense of the body, which will
cause loss of weight.
We have quoted above (page 423 et seq.) the most interesting
parts of the long study made by Vivenot of the changes which
compressed air causes in the circulation and particularly in the
characteristics of the pulse.
He asked himself whether these changes in the form of the
pulse can be explained by the direct, local action of the pressure
on the arterial system. To get the answer to this question, he car-
ried out the following experiment, in which he eliminates, he says,
all the complex elements of the problem, in order to concentrate
on "the contractility of the vessels and the pressure of the blood":
A rubber balloon with a tube about 50 centimeters long is filled
with water, without being stretched, and the end of the tube is tied
shut with a thread. The heart is represented by the balloon, the
arteries by the tube, and the blood by the water.
A sphygmograph is placed over the tube. A weight falls regularly
and always from the same height upon the balloon, representing in
this way the impulse of the heart. Thus a sphygmographic tracing is
obtained.
At normal pressure, this tracing displays the characteristic appear-
ances of the normal pulse under these conditions: rapid, vertical
ascent, acute apex, descent in the form of waves, all the signs of weak
tension in the vessels.
If the apparatus is placed in compressed air, nothing else being
changed, the curve of the sphygmograph is much altered. It then
resembles very closely the tracing given by the pulse itself under
compression. The line of ascent has become oblique, the apex has
changed into a plateau, the height of the impulse is only half as great,
and the polycrotism of the descending line has disappeared completely.
When the weight is allowed to fall from a greater height, so as to
have a stronger pressure upon the artificial heart, the line of ascent
will become straighter, the amplitude of the oscillation will increase,
but there will be no polycrotism. If the apparatus remains a long
time in compressed air, a few drops of liquid will escape near the
ligature, a thing which never happens at normal pressure. At this time,
the sphygmograph gives a tracing which is very similar to that
obtained with the first impulse.
On return to normal air, the original curve appears again, except
with a still steeper ascent and a more pronounced polycrotism.
Zur Kenntniss, etc., P. 373-374.)
He concludes from this experiment and from the similarity of
the tracings obtained both from the arteries and with his apparatus,
in compressed air, that:
Theories and Experiments 475
The changes displayed by the curves in both cases have the same
causes and result from a purely mechanical influence exerted by the
increase of the pressure upon the elastic vessels filled with liquid.
The obliquity of the ascending line, which has become more pro-
nounced in compressed air, indicates a greater resistance of the walls
of the arteries to the impulse of the heart.
The lessened amplitude of the oscillation has two causes:
The diminution of the excursion, of the arterial vessels, the
diastole of which is less because of the increased resistance of the
walls, and the systole is less because, on account of the pressure, the
arteries contain more blood in proportion to their caliber, and cannot
contract as much;
The decrease in volume of the arteries which, in compressed air,
become smaller and contain less blood absolutely; which is shown
clearly by the escape of the liquid from our apparatus after a long
stay in compressed air ... .
Now there are compressed gases in the blood, which are liberated
by the decrease in the air pressure, and which consequently are kept
there by a high atmospheric pressure: and this is a reason why the
mass of the blood, remaining constant, is reduced under high air
pressure to the smallest volume possible ....
From these facts it follows that the action of the compressed air
is exerted most strongly upon the peripheral vessels. (Ibid., p. 375.)
In the following chapter we shall see the value of this odd ex-
periment, the only one which Vivenot performed in the course of
his researches, and what importance the conclusions which he
draws from it may have.
The ideas of G. Lange 27 agree perfectly, as one might have
expected, with those of his collaborator Vivenot. He adds, how-
ever, a few original explanations; this one, for example, which has
reference to the decrease in the number of respiratory movements:
The need of breathing does not result from the influence exerted
upon the outstretched spinal cord by a blood with a reduced oxygen
content; it is the carbonic acid of the blood which produces this need,
the intensity of which grows proportionately to the quantity of this
acid which the blood contains. That is why every increase in the
quantity of carbonic acid exhaled will decrease the need of breathing,
and consequently the number of inspirations, unless a more active
combustion of the blood restores an excess of carbonic acid equal or
superior to the quantity exhaled.
The decrease in frequency of the respiratory movements would
therefore be explained by a greater exhalation of carbonic acid in
compressed air, at least during the stay under the bell and the time
immediately following this stay. (P. 23.)
But G. Lange knows very well that this hypothesis, then agree-
ing with the theory of Brown-Sequard, cannot account for the per-
476 Historical
manent slackening of the respiratory movements. So then he
resorts to another kind of explanation:
I can explain this fact (he says) only by the unquestionable
increase in the strength of the respiratory muscles, which can alone
account also for the increase of the vital capacity of the lungs notice-
able even at the first treatment.
Here he relies upon the conclusions of a memoir by J. Lange,28
which I could not procure:
Dr. J. L., in his work on the physiological and therapeutic effects
of compressed air, concluded from a series of experiments, the accu-
racy of which I can vouch for, that in it the negative pressure increased
considerably during the inspiration, and the positive pressure during
the expiration. If then the respiratory muscles gain strength, we are
justified in assuming that all the rest of the muscular apparatus shares
in this increase of strength. This Dr. J. L. proved by a series of
experiments, and he established it as a fact that if patients have been
subjected to the effect of compressed air for some disease of the lungs,
they feel their strength increasing after a few treatments, and muscu-
lar exercise becomes easier and less tiresome for them from day to
day.
The same author says also: It is difficult, if not impossible, to
measure this increase in strength. Experiments do not give us results
of absolute quantity. They show us, however, that an increase in
power of the whole muscular system is produced, and that it is fairly
large ....
The increase of muscular strength in compressed air may be con-
sidered a proof of the absorption of a greater quantity of oxygen.
This absorption is carried on especially by the lungs, but partly also
by the skin. Sandahl justly states that the skin has a respiratory
power and that under the influence of a strong pressure, which pro-
motes endosmosis, it would absorb more oxygen. (P. 27.)
G. Lange comes next to the slackening of the circulation, and
quotes the explanation of Vivenot:
Could one not somehow explain (he says) the slackening of the
pulse by the fact that the pressure exerted over so large a part of the
capillary system and the small arteries makes the passage of the blood
there more difficult?
The presence of free gases in the blood makes a compression
possible, and the vessels, especially those which are situated on the
surface, contract so much that sometimes even slight hyperemias dis-
appear rapidly.
The observations relating to the effect of the compressed air on
the functions of the nervous system are interesting enough to be
quoted in full; we find again in their explanation the idea already
suggested by different authors, and particularly by M. Junod
Theories and Experiments 477
(page 414) , that the organs contained in the cranial cavity escape
more or less completely the effect of the compression exerted on
the rest of the body:
If more activity and clearness of mind are observed under
increased atmospheric pressure, this phenomenon may be attributed
to another cause than the rise of the barometer of an inch or an
inch and a half, and we cannot draw any conclusion from it in favor
of the increase of pressure. When Junod maintains that under a
certain pressure the sphere of ideas enlarges, and that one becomes
capable of writing verses, his claim seems extravagant to me. More-
over, my observations conflict with those of Dr. J. Lange. He says
that under the influence of compressed air the central nervous system
is stimulated in a peculiar way, that in particular the functions vested
in the cerebral hemispheres are carried on with greater activity, that
in many persons one observes more or less definitely an elasticity
and brilliancy of mind which did not exist before. The patient sub-
jected to the treatment is supposed to experience a mental well
being, and his mind is clearer and freer. In addition, he thinks that
he can consider these phenomena as constant effects of compressed
air.
In my numerous observations, I have noted nothing of the sort.
On the contrary, I have observed in myself and others a feeling of
calmness, generally followed by a tendency to sleepiness.
Compressed air cannot act directly upon the organs contained in
the cranial case, whereas all the other parts of the body undergo its
effects: so one might assume that even a slight increase of the atmos-
pheric pressure brings more blood to the brain. The tendency to
sleepiness would also suggest such a conclusion. Dr. Vivenot con-
ceived the idea of observing this increase of pressure by means of
the dilatation of the pupil.
He placed in a spectacle frame a thread divided into milimeters,
and measured by means of a concave mirror the size of the pupil
before and during the treatment, using candles in both cases, in order
to have equal lighting. Strangely enough, he most frequently observed
a contraction of the orifice of the pupil, which must be attributed
to a stimulation which, as I have already said, was not indicated in
myself by any other sign. (P. 29.)
Let us quote also an interesting discussion of the changes in the
lymphatic circulation:
An increase of appetite is usually observed in persons who have
taken treatments of compressed air for some time. Some of them lose
a little weight at the beginning, but soon their appearance improves
and they gain weight. Dr. J. Lange gives the following explanation
of this fact: The blood contained in the subclavian vein undergoes
suction and therefore the lymph which comes from the thoracic canal
would flow there more abundantly, and besides, the thoracic canal
itself, which is hermetically inclosed in the chest, would also be sub-
jected to negative pressure, and consequently the lymph contained in
478 Historical
it would undergo a suction from which would result a stronger cur-
rent and the presence in the canal of a greater quantity of lymph.
Whether or not this explanation is true, I think that the weakness and
emaciation caused by a disease of the respiratory organs should lessen
as the cure proceeds, and that when the respiration is better, the
appetite is improved. The emaciation at the beginning probably
results from the greater absorption of oxygen, and the effects of this
gas are no longer depressing when the appetite increases. (P. 31.)
The opinions of Elsasser 2<J are evidently only a reflection of
those of Vivenot:
The effect of compressed air depends upon two principal factors:
1. The increased mechanical pressure (a) on the exterior surface of
the body, (b) on the respiratory cavities; 2. the greater quantity of
oxygen and nitrogen breathed in a given volume.
The first factor shows its effect first on the gases contained in the
body, then on the blood capillaries of the skin and the mucous mem-
branes, the walls of which are flattened. The second will act upon the
respiratory exchanges and movements. (P. 9.)
And farther on, developing these principles:
The pressure of an atmosphere and a half results in a compression
of the tissues, a contraction of the diameter of the blood vessels; the
supply of blood in the skin is diminished; slight cases of conjunctivitis
are cured, blistered surfaces and the ears of white rabbits grow pale.
Similar changes are noted in the respiratory mucous membranes;
they become more compact, thinner, less rich in liquids and blood
From this fact, cures of inflammation of the lungs, etc. result ....
What is the result of this forcing back of the blood? Does it not
cause interior congestions? Experience shows that the heart is not
affected by it, but works more quietly; there is no cerebral congestion
. . . . ; but the increase of appetite, of urinary secretion, and of
strength seems to be consistent with a greater quantity of blood.
The second factor, the greater quantity of oxygen, has been too
much neglected hitherto .... If, at normal pressure, a healthy man
breathes 16 times per minute, and absorbs each time 30 cubic inches
of air, he will have consumed 480 cubic inches in one minute. But
under the pressure of 1V2 atmospheres, these 480 cubic inches which
he needs become 320; if he still breathes 16 times, each inspiration will
include only 20 cubic inches; with 12 respirations, it will rise to 26.6
cubic inches; with 8, to 40 cubic inches .... If therefore the proportion
thus calculated is not observed, more oxygen will be introduced into
the lungs in a given time, which explains the statements of the
authors about the greater absorption of oxygen, the increased hema-
tosis, the stimulated organic combustion, etc. (P. 13-17.)
Panum,30 in the work which we have already quoted (pa^e 435) ,
justly criticizes the method employed by Vivenot in measuring the
quantity of carbonic acid produced in a given time;
Theories and Experiments 479
The enormous quantity of carbonic acid found by Vivenot (he
says) results from making the expirations too strong; in fact, taking
his figures, we find that the pulmonary ventilation for 24 hours at
normal pressure is 21,111.2 liters, and in compressed air 19,745.5
(Panum in one experiment gets 1152 liters for himself at normal
pressure). In respiration so greatly forced as that, he finds a produc-
tion of carbonic acid of 1300 grams in normal air and of 1449.5 gm. in
compressed air (Panum gets 816.2 gm. in himself).
As to him, he made his analyses on 60 or even 120 liters of air
expired in a spirometer at different periods in the experiment.
Moreover, he does not give very clear specifications of the manner
in which he carried out this experiment; I can find only that the
compression was 24 centimeters:
I have found no trace in my experiments of this increase in the
production of carbonic acid after the air treatments, of which Vivenot
speaks .... I consider the opinion of Vivenot a mistake, because his
method had no solid basis and could not be used to estimate the
quantity of air which passes regularly through the lungs in a given
time, with quiet and natural respiration; his respiratory rhythm was
forced, not natural ....
If we compare in. my tables the cases in which equal volumes of
compressed air and normal air were breathed, we find that the
quantity of carbonic acid exhaled has increased absolutely and rela-
tively in compressed air. But if we compare the cases where there
was the same volume of air, when reduced to the same pressure,
breathed in free air" or under the bell, we see that a little less carbonic
acid was produced in the compressed air than at normal pressure. In
other words, the quantity of carbonic acid exhaled increases during
respiration in compressed air because of the increase in the mass of
air which passes through the lungs, as a result of this pressure, but
in a proportion a little less than the latter. (P. 143-146.)
But this is exactly the result which Vivenot reached, in spite
of the faulty method which he had used. Panum is surprised at
this agreement:
The experiments of Regnault and Reiset, in which the respiration
of an air with greater oxygen content had not brought a greater
excretion of carbonic acid, seemed to prove a priori that the same
would be true in compressed air. Yet my results were the same as
those of Vivenot, and were contrary to my expectation, which makes
them all the more convincing.
What causes such a difference between the respiration in air with
high oxygen content at normal pressure, and that in normal air at
higher pressure?
We might ask whether it is the oxygen chemically united with
the corpuscles of the blood, or that which is simply absorbed, which
in one case oxidizes more energetically than in the other. If one
breathes superoxygenated air at normal pressure, then the increased
480 Historical
partial pressure also increases the proportion of oxygen in simple
solution in the blood, whereas that which is in a state of chemical
combination there very probably does not vary. This shows that it is
not the oxygen simply dissolved, but the oxygen combined which pro-
duces the carbonic acid, since in the experiments of Regnault this
production did not increase.
We can see likewise that the increase of oxidation and of carbonic
acid production which we observed in compressed air is caused by
the combined oxygen of the blood. (P. 147.)
Passing to another class of phenomena, the Danish physiologist
studies the changes in the respiratory rhythm. We have quoted
in the preceding chapter the data which he obtained. To explain
the increase of the pulmonary capacity, he makes the following
experiment:
I immerse under water in a flask a bladder half full of air; a
second bladder provided with a tube is placed upon the first; the tube
passes through a stopper which hermetically closes the flask, which
therefore is full of water except for the space occupied by the bladders.
The lower bladder represents the intestinal tube and its gases, the
upper one represents the lungs with the trachea, the flask and the
water representing the closed thoracic cavity. If this very simple
apparatus is carried into compressed air, we see that the lower bladder
decreases while the upper one increases in volume.
This result is not at all changed if we use a flask the bottom of
which is replaced by an elastic membrane. The closed bladder behaves
in the same way; but only a part of the space which it leaves free is
filled by the upper bladder; the membrane at the bottom rises.
This shows that it is the compression of the air contained in the
intestine which is the cause of the increase in the lung capacity and
the greater lowering of the diaphragm.
The changes in the respiratory rhythm could not be explained,
Panum says, by the increase in the oxygen of the blood, since this
increase leads to apnea; now in apnea, not only the number but
also the amplitude of the respiratory movements decrease. He
also rejects the hypothesis accepted by Vivenot and G. Lange of
an increase in the power of the inspirator muscles; he justly con-
siders that these authors gave no proof of their assertion. In his
opinion, it is the increase in the average capacity of the lungs,
under the direct, mechanical influence of compressed air, which
causes the deeper inspirations.
In regard to the changes in the pulse and the increase of the
arterial pressure, Panum finds quite contrary to the laws of physics
("ganz unphysikalisch") the explanation of Vivenot, G. Lange,
Sandahl and Elsasser, which attributes them to an alleged decrease
Theories and Experiments 481
in the volume of the blood, as a result of the decrease in volume,
under the influence of the pressure, of the gases contained in it.
Finally, in reference to the symptoms of decompression, our
author, though not having made any experiment on data of this
kind, reaches this conclusion, that:
The morbid symptoms chiefly result from the fact that the air
which has suddenly been liberated in the blood vessels is drawn along
by the circulatory current, and forms embolic obstructions in different
vascular regions. (P. 149.)
The chief purpose of G. von Liebig 31 was to find whether the
quantity of carbonic acid formed is the same in free air and in
compressed air. He describes minutely the complicated apparatuses
which he used; I shall merely say that the analysis of the air was
made on the quantity expired in 15 minutes, by means of a solution
of baryta proportioned by oxalic acid. It goes without saying that
all the figures are accompanied by numerous decimals; but, to com-
pensate for that, the author does not tell whether the subjects were
put on a regular schedule, both of diet and of exercise, which, how-
ever, is far more important than discussions of the length of time
one should shake the vessels to secure complete absorption of the
carbonic acid.
The carbonic acid, the proportion of which was decided in eight
experiments of which Kramer was the subject, really seems to have
been decreased as a result of the compression. At normal pressure,
first, the subject produced in 15 minutes, the first day 8.442 gm. of
C02, the second 7.955 gm.; in the apparatus, successively, 7.614 gm.,
7.784 gm., 7.747 gm., 7.136 gm.; finally, on return to open air, 7.791
gm. and 7.287 gm., that is, an average of 8.198 gm. before the com-
pression; 7.570 gm. during the compression; and 7.539 gm. after the
compression. The decrease then was, during the compression, for
15 minutes, 0.628 gm., or in 24 hours, assuming that it would have
remained the same, 60.3 gm.
G. Liebig, who blends in a common average the experiments in
the open air, before and after the compression, reaches a difference
of only 28 grams, which he declares to be within the order of
physiological differences. I grant this willingly, even for the 60
grams, because he gives none of the indispensable information
about the schedule of his subject.' But then we must admit that of
his numerous analyses nothing is left which could be useful to us
on physiological ground, in spite of the accompaniment of discus-
sions from the standpoint of physics about the effect of water
vapor and of the slightly increased proportion of carbonic acid in
482 Historical
Compressed air over open air (0.197% instead of 0.147%, for ex-
ample) .
G. Liebig also takes up the explanation of the changes in the
rhythmic phenomena Of respiration.
In regard to the increase of pulmonary volume, he expresses
himself as follows:
The barometric pressure acts at the same time upon the surface
of the body and that of the lungs. As it rises, it opposes more vigor-
ously the elasticity of the pulmonary tissue; this elasticity, which is
equal to 35 mm. of mercury, corresponds to 1/24 of the pressure 720
mm. (average pressure of Reichenhall), but is only 1/34 of 1030 mm.
(pressure of the apparatus) ; so that in compressed air the contraction
of the inspiratory muscles has less resistance to overcome. The dia-
phragm is also assisted in its action by the decrease in volume of the
intestinal gases. The inspiration is therefore easier and stronger; for
the same reasons the expiration is slightly delayed, so that one cannot
breathe as quickly in compressed air as at ordinary pressure. The
lungs also collapse less, so that their volume is greater in a state of
repose. (P. 16.)
As for the increased capacity of the chest, which persists after
the treatments are over, like G. Lange, he considers that to be the
result of the helpful exercise undergone by the inspiratory muscles
because of the new position of the thoracic cage in compressed air.
The authors still left to be mentioned were particularly inter-
ested in the symptoms of decompression.
M. Gavarret,32 in the article which we have already quoted
(page 274), also discusses the symptoms affecting workmen:
The return to open air often produces buccal and nasal hemor-
rhages, which generally are not accompanied by any pain. In our
opinion, these discharges of blood are the result of ruptures of capil-
laries caused by the tension of the gas with which the blood is super-
saturated.
The changes caused in the cutaneous circulation at the time of the
decompression seem to us sufficient to explain these symptoms. The
blood, supersaturated with free gases at high tension, flows into the
capillaries, distends them, twitches the innumerable nerve net-
works which surround them, and causes, depending upon the speed
and the intensity of the vascular congestion, sometimes a simple
sensation of heat, sometimes real pains. (P. 156.)
M. Leroy de Mericourt,33 after describing the paralyses which
attack divers using the diving suit, explains them by saying:
We think that we may state that in these cases a lesion of the
spinal cord is produced, and that this lesion must have been a hemor-
rhage. According to the seat and the severity of this hemorrhage, death
Theories and Experiments 483
occurred very quickly, as happened to three cases, or occurred only
after a variable time, as in the other seven cases.
Then, after accepting this hypothesis, he asks himself what the
cause of the spinal hemorrhage can be:
After due reflection (he answers himself), we are inclined to
believe that it is the result of the exaggerated tension of the free
gases, in solution in the blood, as a result of the high pressure to
which the divers may be subjected. In the diving-suit, as we know,
the man is completely isolated from the water by a suit of strong
impermeable fabric and a metal helmet fastened upon the collar of
the suit. Air is admitted to this covering by means of a pump which
communicates with it by means of a flexible tube ending at the back
of the helmet. Nothing regulates the quantity or the pressure of the
air pumped into the suit. Consequently, the workman often receives
too much or too little air; he is compelled to remedy partially the
difficulty in breathing which he experiences by being in constant
communication with the pumptenders by means of signals consisting
of a certain number of tugs given to a signal cord. Nevertheless, by
means of this atmosphere which the man keeps around him, he can
maintain his respiration and remain whole hours under water. But
the greater the depth, and the more prolonged the stay, the more must
the blood be laden with an excess of free gases in the state of solu-
tion. The lack of regulating mechanism for the pressure must often
cause the atmosphere of the suit to be at a pressure greater than is
necessary. From the point of view of physics, the man is really in the
situation of a bottle of water which is charged with carbonic acid gas
to obtain artificial Seltzer water.
When he rises to the surface, if the decompression is not gradual
enough, the gases with which the blood is supersaturated tend to es-
cape with effervescence. Now experimenters who make injections into
the venous system of horses, for example, know that if they intention-
ally allow a small bubble of air to enter with the liquid injected, as
soon as this bubble of air penetrates the cerebral circulation, the
experimental animal falls as if struck by lightning. The effect, in this
case, is only momentary, but if the quantity of bubbles of air ad-
mitted is great, death occurs very soon.
We have thought it best to quote in full this noteworthy passage
which recalls what M. Bucquoy had already said (see page 459),
and which contains in the form of a hypothesis an exact description
of what really takes place, as we shall show in the second part of
the present book. But by a strange inconsistency, which shows
what influence the old ideas about the mechanical effect of the
decompression had gained over the best intellects, M. Leroy de
Mericourt, instead of adhering to the idea of intravascular gaseous
obliterations, remains imbued with the hypothesis of hemorrhages,
resulting from the forcing back of the blood. He then asks himself
484 Historical
why "they occur in the special nervous center rather than in the
cerebral mass," and he answers:
The cranial case and the vertebral column form two coverings
which are equally incompressible; consequently, when the blood is
driven from the entire surface of the body and the compressible
splanchnic cavities, it must tend to congest the cerebro -spinal axis.
The circulatory system of the spinal cord, compared to that of the
brain, is infinitely richer, as the congestions show; finally, in the
sponge fisherman, it is the legs which become most weary, because
during his stay under water, he must constantly walk and climb up
and down the rocks. Perhaps these are the causes which account for
the fact that the spinal cord is the favorite seat for the symptoms.
We give this explanation, of course, with the greatest circumspection.
M. Bouchard,34 in his study of the Pathogeny of Hemorrhages,
includes the symptoms of compression and decompression, which
he considers as due to abdominal, spinal, and cerebral congestions
and hemorrhages. The manner in which he imagines they are pro-
duced is very interesting; it is borrowed, he says, from M. Marey:
When the compressed air makes its way into the lungs, there is
no longer any tendency for a vacuum to be made in the chest, as in
the case of naked divers; pulmonary congestions are no longer to be
feared. However the abdomen is normally distended by gases; since
the outer air does not enter the intestine, these gases are compressed
and occupy a volume which is in inverse proportion to the intensity
of the compression. The volume of the abdomen will become four
times less, if the pressure is four atmospheres. Then the wall is
everywhere crowded against the spinal column and thus forms an
anterior concavity. But this wall is not inert; it tends to become
straight again, through its tonicity and even its contractility, and con-
sequently to lessen in the abdomen the pressure which had been
counterbalanced by this pushing back of the wall; it acts like a huge
cupping-glass, which would attempt to accumulate in the abdomen
the blood from the other organs. And in fact, general anemia is
produced.
This plethora of blood in the abdominal organs is not, however,
the cause of hemorrhages, except perhaps in the spleen.
So much for the explanation of the visceral congestions during
the compression. But at the time of the decompression, an inverse
phenomenon would take place:
It is at the time of the decompression that the hemorrhages occur,
at the moment when the intestinal gases, regaining their volume and
distending the abdominal wall in the opposite direction, cause the
organs of the belly to undergo a positive pressure which will drive
out the blood stored in their interior, and direct it suddenly towards
the other organs, the vessels of which, since they have lost their
tonicity, .... do not adapt themselves quickly to this sudden inroad.
Theories and Experiments 485
Then appear the cases of epistaxis and hemoptysis, sometimes passing
or fatal apoplexies, accompanied in certain cases by temporary or
permanent hemiplegias, and finally these fleeting or persisting para-
plegias, which M. Barella observes in laborers working in caissons, and
which, according to M. Leroy de Mericourt, would be one of the most
common causes of death in sponge fishermen.
This explanation, however, does not satisfy M. Bouchard, who
then quotes the ideas of MM. Rameaux and Bucquoy on the gases
of the blood:
But this sudden congestion, at the time when the blood flows
back from the abdomen towards the other organs, is perhaps not the
only cause or the real cause of these hemorrhages, or at least of a
certain number of them: of those, for example, which take place in
the incompressible cavities, the skull and the spine. Another inter-
pretation has been given, which seems probable. Gases are dissolved
in liquids in proportion to their tension; the blood of a man who has
remained for several hours under a pressure of four atmospheres
should therefore contain a much greater proportion of carbonic acid
than in the normal state; and this dissolved carbonic acid will re-
turn to the gaseous State as soon as the outer pressure lessens. If
the decompression takes place slowly, the blood as it passes through
the lungs, can release the surplus carbonic acid, and no symptom will
appear; but if the decompression is sudden, the carbonic acid will
tend to break out in gaseous form even into the vessels, and by its
sudden expansion, or by the obliteration of small vessels in which it
cannot circulate, will cause ruptures and extravasations. (P. 99.)
M. Bouchard applies this idea to the formation of painful mus-
cular swellings, of which the authors whom we have previously
quoted have spoken:
These swellings are not inflammatory, they are not exudates nor
extravasations. They disappear immediately simply through return
to compressed air, and are never followed by ecchymotic spots. When
the swelling exists, it is not accompanied by throbbing or redness, so
that we can hardly attribute it to an exaggerated arterial dilatation,
as M. Foley has done. If it is true that muscular labor is an important
source of carbonic acid, might we not assume that the muscles which
have exercised most are laden with carbonic acid dissolved in the
very tissue, and that, at the time of decompression, this acid is liber-
ated in gaseous forms, and then is redissolved by a new compression?
(P. 101.)
We now have to speak of an author who wrote after our first
personal researches; but we place him here because he seems to
have given little heed to the experiments which we had already
published.
After reporting the data which he observed, the summary of
486 Historical
which we gave in the first chapter (page 395, et seq.), M. Gal35
comes to the theoretical explanations, or, as he says, to the pa-
thogeny of the diseases caused by work in compressed air.
He shrewdly distinguishes the cause of diseases with slow be-
ginning from that of symptoms which come on suddenly. For the
first, he accepts, he says, the explanation of M. Foley; but at least
he has the undeniable merit of expressing it in a comprehensible
form:
We have seen that the blood of the caisson worker and the diver
is richly oxygenated, and it seems as if it would be hard for anemia
to occur under such conditions. But on the other hand, we have seen
that sensations perceived by the sense organs are much less distinct in
compressed air; therefore the spinal cord and the brain, since they
receive fewer stimuli, will produce less nervous energy, and the effect
of the sympathetic system upon the metabolism of the tissues will be
weaker than in the normal state.
As long as the workman has not exhausted his reserve of nervous
influx, he will not suffer; the increase of his appetite will furnish/ his
blood with the materials which it needs to consume its oxygen; but
when he has exhausted his reserve, since production is less than the
expenditure, the functions of the sympathetic system will be carried
on imperfectly, and the patient will become mortally ill. Then he will
be most subject to the other diseases with sudden beginning and
immediate danger.
As for the other diseases, they are all "due to congestion." On
that, says M. Gal, everyone is in agreement; but this is not the case
when their method of production is to be explained.
On this point, he appears very eclectic. He considers as "pos-
sible," after my experiments, the opinion which attributes symp-
toms to a liberation of gas in the blood. But he prefers the ex-
planation of M. Foley about:
The too violent reaction caused either by too sudden a decom-
pression, or by the lack of reaction in places where it usually takes
place, and where it is harmless, especially the skin. (P. 60.)
We confess that this is anything but clear. A little farther on
he adds:
In regard to the divers who died suddenly, the opinion of M.
Bucquoy and M. Leroy de Mericourt (he is referring to the efferves-
cence of gas) is very probably true.
As for the other divers, who died sooner or later after the acci-
dent, they all had paraplegias. In all of them the lesion of the spinal
cord had occurred suddenly, which one can connect only with a con-
gestion, a hemorrhage in the substance of the spinal cord, or a
compression by hemorrhage in the vertebral canal.
The cases of rapid cure observed and the invariability of double
Theories and Experiments 487
paraplegia make me incline towards congestion in most cases; but
we have no proof that the gaseous tension did not sometimes cause
hemorrhages.
Finally, in the case which we observed, in which paralysis began
more than 24 hours after the last dive, we can see only a condition
rather abnormal in divers, a passive congestion in which the effect of
the gases of the blood cannot be admitted.
We have laid stress on severe congestions; all that we have said
can be applied to all diseases of divers, depending on varying degrees
of severity. The afflux of blood and perhaps the effect of the gases
which it contains takes place at different points, and the severity of
the attack depends upon the importance of the organ. The "fleas,"
the muscular and arthritic pains, the hemoptyses or nasal hemorrhages,
the inflammations of the ear, and the visceral congestions are always
the result of the same cause: a reaction of the blood which is too
violent or badly directed, whether this reaction is due, as Foley thinks,
to the nervous influence which revives during the decompression, or
whether the action of the gases dissolved in the blood must be
involved. (P. 60.)
From the practical and prophylactic point of view, like all the
authors who preceded him (except M. Foley), M. Gal draws this
conclusion that the decompression must be made slowly; he also
makes the recommendation that the greater the depth reached, the
shorter the time under water should be. Here, in fact, is the
schedule followed under his supervision:
Up to 25 meters, even in uniform depths, the period of work under
water was an hour and a half. From 25 to 30 meters, the time was
reduced to one hour. From 30 to 35 meters, only a half-hour. Between
35 and 40 meters the divers stayed on the bottom only a quarter of an
hour.
Our fishermen never went below 35 meters. The Greeks, who are
more daring, went to 54 meters, in 1867.
At the same time that the length of the shift was decreasing, the
time spent in the decompression was increasing. A half-minute per
meter was the rule first established; but the fishermen were never
willing to submit to it. They ascended at about 4 meters per minute.
(P. 72.)
iPars altera. Rome, 1681.
2 hoc. cit. Collect, acad., foreign part, Vol. I, p. 46-61, 1755.
3 Elementa physiologiae corporis hutnani, Vol. Ill, 1761.
4 Extrait d'une lettre de M. A. an citoven Van Mons. Ann. de Chimie, Vol. XXXVII.
1801.
5 Article Air in the Diet, des Sc. med. Vol. I, p. 218, 1S12.
6 Tractatus physioo-medicus de atmosphera et acre atmospherico. Cologne, 1816.
7 Recherches sur les causes du m&uvement du sang dans les vaisseaux capillaires. C. R.
Acad, des Sc, Vol. I, p. 554-560, 1835. These different experiments are reported in detail in the
memoir of this same author, included in Volume VII of the Memoires des savants etrangers.
8 Etudes de physique animate. Paris, 1843.
9 Note sur la carbonometrie pulmonaire dans I'air comprime. Gas. med. de Lyon, 1849, p.
168.
10 This method is explained in a previous work by the same authors, entitled: Recherches
sur les quantites d'acide carbonique exhale per le povmon a I'etat de sante et de maladie. Ibid.,
p. 39-50.
11 hoc. cit. Essai, etc.; 1850.
12 hoc. cit. See above, Title II, Chapter I, section 2. ,
488 Historical
13 Note sur tes effets physiologiques et pathologiques de I'air comprime. Ann. d'hyg. publ.
et de med. leg., 1854, Second series, Vol. I, p. 279-304.
14 Loc. cit. De I'air comprime, etc. Lyons, 1854.
15 Etude clinique de I'emploi et des effets du bain d'air comprime dans le traitement des
diverses maladies. Paris, 1855.
M Loc. cit. Ueber dcr Einfluss, etc. Muller's Arch., 1857.
"Loc. cit. Des effets de I'air comprime, etc.; 1860.
18 Loc. cit. De I'air comprime; 1861.
19 Loc. cit. Des accidents, etc.; 1862, 1S63.
20 Loc. cit. Du travail, etc.; 1863.
21 Rapport sur le travail de M. Foley, lu a la Soc. med. a" emulation de Paris, session of
August 1, 1863.
22 Loc. cit. Paralysis caused, etc.; 1863.
23 Loc. cit. Ueber die Wirkungen, etc.; 1862.
24 Loc. cit. Die camprimirte Luft, etc.; 1863.
23 Loc. cit. See the list of Vivenot's works, in Chapter II.
28 Mittheilungen iiber die physiologischen Wirkungen und theropeutische Bedeutung dcr
comprimirten Liift. Wiesbaden, 1865. Translated from the German by Dr. Thierry-Mieg.
Paris, 1867.
27 Ueber comprimirten Luft, Hire physioligischen Wirkungen and Hire theropeutische
Bedeutung. Gottingen, 1864.
28 Loc. cit. Untersuchungen, etc.; 1868.
29 Loc. cit. Zur Theoric, etc.; 1866.
30 Loc. cit. Ueber das Athmen, etc.; 1869.
31 Loc. cit. Article Atmosphere; 1867.
32 Lac. cit. Considerations, etc. 1869.
33 De la Pathogenie des Hemorrhagics. Paris, 1S69.
34 Loc. cit. Des dangers, etc.; 1872.
Chapter IV
SUMMARY AND CRITICAL COMMENTS
I shall now summarize, as I did for decreased pressure, first the
physiological symptoms brought on by the use of compressed air
and the more or less serious conditions which have often followed
it, and finally the theories which the authors have advanced to
explain all these phenomena.
1. Physiological effect of compressed air.
It appears very clearly from the data given in Chapter I that
the phenomena which are to be reported here are divided into two
categories very different in their origin, and which we should, for
fear of confusion, separate in the exposition, although the distinc-
tion has not always been made by the authors. Some, in fact,
appear even during the compression, and are the result of the stay
in compressed air; others occur only at the time of return to normal
pressure; they are the result of the decompression, and their in-
tensity is in proportion to the speed of the decompression and
the degree of the compression. This differentiation, which was first
suggested in a rather vague manner by Pol and Watelle, will
govern our summary.
A. Phenomena Due to Compression.
Pains in the ears. Pains in the ears have been noted by all
observers during the process of compression as well as during the
decompression. All have given the exact explanation of them; they
have shown that since the Eustachian tube, obstructed for different
reasons, does not permit the compressed air to enter the tympanic
cavity, the tympanic membrane is pushed back and distended,
causing pains which may be unendurable. Sometimes it is even
ruptured, as happened to M. Cezanne, at the bridge of Sgedezin.
489
490 Historical
Similar symptoms, but less severe, accompany decompression.
They can be checked by opening the tube, either by the movements
of swallowing, or, and this is a more certain method, by making
a strong expiration with the nose and mouth closed.
These repeated procedures result in reestablishing the per-
meability of the tube, the obliteration of which is a frequent cause
of deafness; hence come, no doubt, the improvement in this in-
firmity which is often observed in compressed air, and the effec-
tiveness of the treatment originated by Pravaz. But the question
is complicated by the direct effect of the compressed air upon the
mucous membranes, of which I shall speak presently.
Voice. The voice is impaired in compressed air: one talks
through the nose, Triger says; it rises in pitch, and in this regard
Vivenot made an exact observation upon a well-known woman
singer who gained a half-tone in the apparatus. The act of whis-
tling becomes impossible beginning with 3 atmospheres, as Triger
had already noted; it even takes a certain effort to talk, according
to Pol and Watelle. All of this is quite evidently due to the in-
creased density of the air.
Respiration. It has been very definitely determined that the
maximum respiratory capacity increases considerably during the
stay in compressed air. The diaphragm and the base of the lungs
drop; respiration therefore goes on in a certain constant state of
enlargement of the thorax. No doubt that is one of the causes of
the improvement in asthmatic patients, in whom pulmonary expan-
sion then takes place more fully. This change, which increases
with each of the first treatments, persists for a longer or shorter
time after return to open air.
The frequency of the respiratory movements decreases con-
siderably; everyone agrees on that; their amplitude increases in
inverse proportion. But after all, a smaller volume of air under
pressure passes through the lungs in a given time than of ordinary
air. At least that seems to be the conclusion to be drawn from the
figures of Vivenot and Panum; but it must be said that no direct
experiment has been made, and that these conclusions have been
drawn from calculations in which one had to take into account
the amplitude of one or several respirations and the number of
respiratory movements per minute: complex calculations strewn
with causes of errors of a physiological order.
As to the rhythm itself, Vivenot and Panum contradict each
other completely in their statements; however, the point is of little
importance.
Summary and Discussion 491
Circulation. The decrease in the pulse rate is also a matter of
general observation; M. Bucquoy alone (page 374) has made a
contradictory statement. In highly compressed air, Pol and Watelle
observed the rate to fall from 80 to 50; the change is especially
great when there was an abnormal acceleration. On return to
ordinary pressure, the usual rate is restored.
The pulse undergoes still other changes, in regard to which
the tracings of Vivenot give us definite information (Fig. 10-13,
pages 424, 425); its amplitude is much lessened, and it shows all
the characteristics of exaggerated arterial tension.
No direct experiment has been made to measure in animals
the changes in the blood pressure and the speed of the blood flow.
The capillary circulation is evidently much changed. The skin
and the mucous membranes grow pale, especially when they were
the seat of congestion or inflammation; in regard to this important
point in therapeutics, the observations of physicians are more con-
vincing than the experiments made by Vivenot on the ears of
white rabbits.
The blood becomes a brilliant red in color; this has been ob-
served particularly in caisson workers. The venous blood drawn
from the arm, as Pol and Watelle were the first to note (page 367) ,
looks as if it were arterial, a certain indication of the greater pro-
portion of oxygen which it contains: according to these authors,
this redness of the blood persists for some time.
Secretions. The only important observation which has been
made concerns the increase in the urinary secretion; but no exact
measurement has been taken, and no analysis of the urine has been
made.
Some observers have spoken of the dryness of the skin,- but it
is difficult to get exact estimates on this point.
Nutrition. Very different estimates of the variations in the
weight of the body have been made by different authors. The
physicians of caisson workers and divers declare that there is a
loss of weight; those who used compressed air with a therapeutic
purpose consider that there is an increase in weight. Besides the
fact that there may be a great difference in this regard between
the effect of a pressure of 3 atmospheres and that of the pressure
of a few centimeters of mercury, one can hardly compare caisson
workers, men who are exhausted by their hard labor, who seek
dangerous assistance in alcoholic beverages, and who are generally
much undernourished, with subjects who are in excellent hygienic
conditions and who can satisfy completely the increased appetite
492 Historical
which a stay in the bells seems to produce. On this point then, it
hardly seems possible to reach any conclusion.
The observations of Vivenot on an increase in body tempera-
ture, of from 0.1° to 0.4°, do not seem to me at all convincing.
As to the production of carbonic acid in a given time, we shall
speak of that in the next section.
Innervation. It is very difficult to see, in the accounts of the
authors, any clear indications in regard to sensory functions. Taste
and smell are disagreeably affected by the impurities in the air
of the caissons, and the ear is affected by the distention of the
tympanic membrane.
They do not agree in regard to the functions of the brain. Col-
ladon (page 357) mentions a stimulation which resembles intoxi-
cation; M. Junod (page 414) states that "the functions of the brain
are stimulated;" M. Foley, when he left the caissons, it is true, was
attacked by an excessive cerebral excitation which made him
"catch himself in the very act of babbling, in spite of all his
efforts." J. Lange (page 477) states that constantly, even in the
apparatus, "one experiences an activity and coolness of mind which
did not exist before." On the opposite side, Dr. Francois says that
especially at the beginning one feels a sort of drowsiness, and
according to G. Lange, the only phenomenon which one can note
is "a feeling of calmness generally followed by a desire to sleep."
B. Phenomena Due to Decompression.
Their severity depends, as we have said, upon two factors to
which it is proportional: the degree of pressure reached, the speed
of the decompression.
Up to 2 atmospheres, no symptom seems to appear in the work-
men. Above that, there appear more and more frequently
cutaneous itchings, "puces" (fleas) , which finally cause very keen
pains; they are much more common in caisson workers than in
divers. Then come painful swellings of the muscles, particularly,
according to the accurate note of M. Foley, of those, muscles which
worked hardest during the stay in compressed air; at the same time,
periarticular pains. Not until the pressure is above 3 atmospheres
do really serious symptoms occur: sensory disturbances, blind-
ness, deafness, disturbances of locomotion and general sensitivity,
especially paralysis of the lower limbs, the bladder, the rectum,
and, much more rarely, the thoracic members; cerebral disturb-
ances, loss of consciousness; finally, sudden death.
These symptoms do not appear until after a few minutes and
Summary and Discussion 493
sometimes a few hours after leaving the caissons or the diving
suits; in one case observed by M. Gal, the paraplegia did not begin
until twenty-four hours after the decompression had been made.
The time given to decompression is, moreover, extremely variable;
in divers, it takes place with a speed which the good advice of M.
Denayrouze could not reduce; for the caisson workers, it was at
most three or four minutes per atmosphere.
Slight disturbances, cutaneous, muscular, and articular pains
always disappear in a rather short time. The same thing is often
true of more serious symptoms, and even of loss of consciousness.
But too frequently the paralyses of the lower limbs are persistent,
and we have reported numerous observations which make a sad
picture of these unhappy men whose sufferings death almost always
ends after a period of variable length. In none of the cases which
we reported was a paraplegia which lasted more than two days
ever completely cured.
The irregularity between different persons in regard to the
effects of decompression is one of the strangest circumstances
revealed to us by this study. We have seen by many examples
that, of several persons subjected to the same pressure and de-
compressed at the same rate, some remained absolutely immune,
others had only slight symptoms, whereas one among them might
be attacked severely. Similar variations occur in many other cir-
cumstances, even a mere departure from the ball shows similar
irregularities. But the strange fact about the present case is that
these symptoms are attributed, and justly, as we shall prove, to a
purely physical cause, and physics should be the same for everyone.
But the irregularity does not exist merely between different in-
dividuals; it exists in the same person, following circumstances
not well determined. It is not rare to see a workman, hitherto
spared, attacked when leaving a pressure the same as, sometimes
even lower than, those the removal of which he had already
endured without any ill effect. The commonplace and ready excuse
of alcoholic or other excesses has often been advanced to explain
these facts; but sometimes this explanation, which is not one at all
from the standpoint of physics, was completely wanting. The only
circumstance on which observers agree is the length of the stay in
compressed air; the longer it is, the more are the symptoms to be
feared, so that certain authors have concluded that the shifts, that
is, the intervals of work in the caissons, should be made more
numerous, without considering that the decompressions, which
cause the symptoms, would thus be increased in number also.
494 Historical
The rule to decompress slowly, aside from any theoretical idea,
has been accepted by all authors and proclaimed by the workmen
themselves, although in practice the intense cold which accom-
panies the decompression urges the latter to make haste. M. Foley
alone seems not to consider it important, and, on the contrary, ad-
vises rapid decompression (page 377).
2. Theoretical Explanations.
Here again we must separate the symptoms observed during the
stay in compressed air from the symptoms of decompression.
A. Phenomena Due to Compression.
Of course, there could be no question here of seeking elsewhere
than in the compressed air the cause of the symptoms reported
by experimenters or workmen; the strange hypotheses which we
have discussed in regard to mountain sickness could not be sug-
gested here. But this effect of compressed air was considered by
some from the physico-mechanical point of view, by others from
a purely chemical standpoint. I recall only for the record the
so-called explanation given by Brize-Fradin (page 444) , which ad-
vances the theory of "vital force," and then has recourse to it to
"change general laws" and settle things according to his desire.
Physico-mechanical Explanations. Let us set aside, first as
really not worthy of discussion, the idea that air compressed to
several atmospheres would hinder the movements of locomotion,
and, second as too apparent, the effect of compressed air on the
tympanic membrane, of which we have already spoken. We are
first faced by the explanation which we have had to combat in
speaking of decompression, that is, the difference in the weight
sustained by the body.
We have quoted the calculations which Guerard took pains to
make to show to what a crushing weight a man would be exposed
who is working under a pressure of several atmospheres. So the
workmen of the Kehl bridge would have had to sustain an addi-
tional weight of 54,000 kilograms. In fact, if, as we have already
shown (page 341), elementary physics did not pass sentence on
these ideas in the name of the incompressibility of liquids and
solids, these figures alone should have warned the authors of the
enormity of the error which they were committing. However,
almost all have accepted this explanation; M. Foley expresses it in
striking words: "As soon as one enters the caissons, one is flat-
tened" (page 464).
Summary and Discussion 495
Almost all the authors, I repeat, even the shrewdest and the
best qualified, even Pravaz, Bucquoy, Vivenot, etc., believe in the
direct and mechanical effect of the pressure. What could draw
such keen intellects into such an error? A very accurate observa-
tion, made by all observers: the pallor of the skin and the mucous
membranes in workmen or experimenters, and especially in
patients, when the mucous membrane was inflamed. In rarified
air, we have seen, the veins and the superficial capillaries are filled,
as if the blood was forced to the periphery; in compressed air,
these vessels are emptied, as if the blood was forced back into the
interior. Thence came, in the first case, the theory of the general
cupping-glass; in the second, that of the crushing weight; "the
compressed air," says M. Foley again, who frequently returns to
this idea with singular energy, "everywhere flattens the mucous
membrane which is exposed to the air" (page 375).
The other authors are generally more prudent; they feel em-
barrassed by physics, which protests against their theory. Nothing
is more curious than the attempts of M. Bucquoy to escape from
this contradiction; but his theory of pressure decreasing pro-
gressively from the skin to the deep tissues is not tenable (page
459) . I also call attention to the ideas of M. Junod, G. Lange, and
M. Leroy de Mericourt about the supposed forcing of the blood into
the brain, due to the fact that since it is protected by the cranial
case, the brain cannot be compressed directly like the rest of the
body; these authors have forgotten that the pressure is applied
instantaneously to the spinal cord and the brain by other paths
than the blood vessels, so that there is equality of pressure in this
organ as there is elsewhere, and the circulation of the blood in it
cannot be changed at all.
But even if we can understand that the complexity of the con-
ditions presented by the human body, considered as a whole, has
drawn distinguished intellects into such astonishing physical errors,
we can hardly explain why, when the question was reduced to its
simplest terms, they did not immediately recognize what a mistake
they were making. And yet we have seen Vivenot, with the aim
of explaining the changes which a stay in compressed air causes
in the form of the pulse, carry out the strange experiment reported
above (page 474), and maintain that a pressure of a third of an
atmosphere is enough to change the volume and the elastic reaction
of a rubber ball filled with water.
I was curious enough to repeat this experiment, not to enlighten
myself in regard to it, but to learn what could have given Vivenot
496 Historical
graphic tracings different in normal air and in compressed air;
from my attempts I concluded that very probably Vivenot had not
closed his apparatus tightly, and that besides he had left air in it.
We understand that it is absolutely useless to dwell on conclusions
which are "ganz unphysikalisch," as Panum says very truly. The
strangest part of the matter is that this experiment, so oddly con-
ceived and so poorly carried out, has been accepted and praised
on both sides of the Rhine. Vivenot has made an experiment! they
said. And that is enough for many people; for there is a whole
school of medicine, the followers of which, of course, have never
frequented laboratories, for whom the word "experiment" answers
for everything, like the "cream tart" of the comedy.
Pravaz did not fail to apply to compression the theory which
we have already quoted (page 345) in regard to decompression.
According to him, the blood is forced more energetically into the
interior organs at the time of the inspiration in compressed air,
because the exterior pressure acts more vigorously upon the venous
system. But, as we have already said, it must be proved that in
compressed air the intra-thoracic negative pressure is stronger than
at one atmosphere. The conclusions of Vivenot say so, it is true,
but I was unable to find the proof of it in his book.
Finally I shall mention the interesting theory developed by
M. Bouchard (page 484). According to him, the abdominal wall,
crowded in by the pressure on account of the decrease in volume
of the intestinal gases, would tend to resume its shape through its
elasticity, and thus would exert upon the abdominal organs a sort
of suction, which would cause a storing up of the blood there: the
result being visceral congestions and general anemia. For my part,
I cannot accept this original idea; it is not only the abdominal wall
which is pushed inward; the diaphragm is in the same situation,
and we have seen that the vertical diameter of the chest increases.
Now it seems to me impossible to admit that these muscular mem-
branes present sufficient elasticity to resist the compression and
thus act as a cupping-glass: on the contrary, they should, especially
the diaphragm, yield to it very passively.
Nevertheless it is true that, for various reasons, the blood seems
to be pushed back from the periphery towards the more deeply
situated organs; the result is important modifications in the cir-
culation and the metabolism of the different parts of the body,
modifications which may have been of great therapeutic value, but
from which the health may suffer, when they continue too long.
Summary and Discussion 497
Variations in the respiratory amplitude and rhythm have also
been explained by the mechanical action of compressed air.
Some, like Pravaz, have thought that compressed air promotes
pulmonary expansion, by opposing more energetically the elastic
reaction of the tissues. That is the converse of the theory sug-
gested in regard to decompression, the inexactness, or at least the
great exaggeration, of which we have shown.
Others, with much better reason, have cited the effect of intes-
tinal gases. In fact, they form the only part of the organism upon
which the pressure of the air can act directly. Even though their
volume cannot increase in the phase of rarefaction, as we have
seen, because of the two orifices which allow an excess to escape
so easily, it can and evidently must decrease following the Law
of Mariotte, and indefinitely, as the outer air is more compressed.
And this really does take place; caisson workmen, whom I have
questioned, have told me that they were compelled, when once in
the caissons, to pull up the buckle of their pantaloons because of
the retraction of the belly.
Although this fact has been established, I cannot accept the
conclusion which Pravaz draws from it (page 448), that the in-
creased elasticity of these gases hampers the action of the dia-
phragm, and decreases the vertical expansion of the thorax, but
increases the expansion of the chest in the other two directions.
Besides the fact that this hypothesis hardly seems tenable, the
measurements obtained directly by Vivenot by means of percus-
sion and auscultation show that in compressed air the lungs drop
lower than in the normal state.
To disclose the mechanism of the increase of the thoracic cavity,
Panum performed an experiment which we reported above (page
480). It has only one defect, namely, that it was useless to make
it; certainly, if we are given a tube closed at its ends by two mem-
branes of unequal thickness, filled with water and containing be-
sides a bladder full of air, if this apparatus is put under pressure,
we shall see the bladder decrease in volume and the two mem-
branes pushed into the tube in inverse proportion to their thick-
ness. Very evidently something similar must take place in the
abdomen, between the gases of the intestines on the one hand and
the diaphragm and ventral wall on the other. The whole interest
of the question lies in knowing in what proportions these last-
mentioned organs tend to invade, pushing from without inward,
the space which was occupied by the intestinal gases, now dimin-
ished in volume. But Panum's experiment says nothing about that.
498 Historical
Chemical explanations. The idea that under a greater baro-
metric pressure the blood, as it passes through the lungs, is laden
with a greater proportion of oxygen, is a very natural idea, which
was accepted by all the authors, up to the time of and including
Brize-Fradin (page 444). It found an obvious confirmation in the
observation made by Pol and Watelle, Frangois, Foley, and all the
physicians who attended caisson workers, that the blood drawn
from the veins during the compression, or even some time after
the decompression, is red and arterial in color. The apparently
contradictory experiments of M. Fernet (page 249) did not make
much impression on the authors in the face of this very obvious
fact. Only M. Bucquoy (page 459) tried to discuss them; in his
opinion, it is only the dissolved oxygen whose proportion increases,
because M. Fernet has proved that the blood corpuscles do not
absorb a greater quantity of oxygen in compressed air than in free
air. The other authors merely state that the blood is richer in
oxygen, and draw from that all the conclusions which they think
inspired by logic, a .guide which one must always distrust in these
complex matters.
For M. Foley, for example, "the hyperarterialization" of the
blood cannot be doubted, and it results in "an enormous consump-
tion of the different tissues, because of the excess of oxygen which
penetrates them." But the existence of this increase in the intra-
organic combustions would have to be proved.
But the experiments of MM. Regnault and Reiset, showing
that animals which breathe in a medium with very high oxygen
content do not absorb more of this gas and do not form more car-
bonic acid there than in ordinary air, showed that the idea of an
increased chemical activity was not very probable. Pravaz, the
only one who with Panum (page 480) seems to have understood
the import of the objection, makes a rather unsatisfactory reply to
it (page 448) in such a way as to compromise his reputation as a
physicist a little. But he did have two of his plipils, Hervier and
Saint-Lager, perform experiments tending to settle the difficulty
directly.
We know what complicated conclusions (page 449) these ex-
perimenters reached when they tried to determine the modifica-
tions which a stay in compressed air makes in the excretion of
carbonic acid and consequently in the consumption of oxygen. I
shall not try to discuss them, because such researches are of value
only because of the method employed; I have already stated that
this method was extremely faulty. In so delicate a matter, in
Summary and Discussion 499
which one may assume that the differences will be very slight,
it is indispensable to observe scrupulously both chemical precision
and above all physiological exactness.
It is not the first one of these conditions which is missing, at
least apparently, in the work of Vivenot. If we may believe his
figures, the analysis he made of the carbonic acid contained in one
expiration was exact down to the sixth decimal, and that by itself,
I confess, would be enough to make me distrustful. Thus the
quantity of carbonic acid exhaled in 24 hours at normal pressure
being 1300.37760 gm., in compressed air it would be 1449.49350 gm.
That seems very conclusive. But how were these figures obtained?
By analyzing the product of one expiration "as strong as possible,
but made without great efforts" at normal pressure, which gave
0.2176 gm. of carbonic acid, and of one expiration under compres-
sion, which gave 0.2676 gm.; by taking into account the average
number of respiratory movements per minute, which was 4.15 for
the first case and 3.76 for the second; and finally, by multiplying
the number thus found by 60 then by 24.
As for me, I refuse to grant any sort of value to figures ob-
tained by a method so absolutely contrary to what true precision,
physiological precision, requires. To take as a basis one expira-
tion, made at the rate of 3.76 respiratory movements per minute,
certainly extraordinary conditions, is to expose oneself in the name
of the experimental method to the severest criticisms. I do not
hesitate to say, without going into the details of the experiments,
without laying stress on the "rubber tubes not hermetically closed"
(page 470) , that all this part of Vivenot's work, in spite of his in-
numerable tabelles and his columns of figures in which the table
of logarithms has "worked wonders," should be considered null
and void.
This is also the opinion of Panum, who studied the same ques-
tion, under conditions which are better, no doubt, but are still open
to reproach. However, his experiments give evidence in the same
direction, and tend to show that in compressed air there is more
carbonic acid produced in a given time than at normal pressure.
I admit that to my mind this fact is not proved; a glance at the
table published by Panum is enough to justify my doubts even
about the results of his experiments; for we see that after all there
are only four of them which are comparable and under normal
conditions, and that of these four only one was made at ordinary
pressure. Moreover, the respiration was carried on for only 10
500 Historical
to 12 minutes; finally, nothing was said of the diet to which the
subject of the experiments was limited.
The increase in the quantity of carbonic acid exhaled in com-
pressed air, admitted without argument by Pravaz, M. Foley, and
the German physiologists, led them to conclude that a greater
quantity of oxygen was absorbed even during the compression.
Hence a whole series of conclusions, already glimpsed by the earlier
authors: nervous stimulation, muscular energy, combustion of the
tissues are easily deduced from it. Hence the increase in the quan-
tity of urine excreted (?), the slight rise in temperature (?), the
insatiable appetite, which causes an increase in weight if it can
be satisfied, and a loss of weight under opposite conditions. All
that links up very well, one must admit; but the method which
bases the accuracy of the premises upon their harmony with the
conclusions is a very dangerous one: it never proves anything to
the mind of an experimenter. Therefore I do not dwell upon these
data, all the details of which I have given above.
B. Phenomena Due to the Decompression.
Physicians who have attended caisson workers and divers work-
ing in suits have been unanimous in attributing to congestions of
the blood, sometimes going as far as hemorrhage, the symptoms
following decompression: congestion of the lungs, the abdominal
viscera, and particularly the encephalic and spinal nervous centers.
But they have not clearly determined the method of producing
these congestions, far from it.
Pol and Watelle believe that the congestion is produced during
the very act of compression by the centripetal driving back of the
blood; if it does not produce its effect then, it is because the super-
oxygenated blood has no harmful effect upon the organs. At the
time of decompression, the blood loses oxygen, and the usual con-
sequences of congestion appear (page 452). I confess I do not
understand very well how the physicians of Douchy could reconcile
their theory with the cases which they observed themselves in
which the most serious symptoms existed at the exact time when
the venous blood was brilliantly red.
M. Foley, in his explanation of the "post-caisson congestion,"
is so vague that I prefer to refer the reader to the word-for-word
quotations which I made from his memoir (page 463). Babington
and Cuthbert (page 466) do not express themselves much more
clearly: in their opinion, the protection of the skull and the spinal
column would prevent, at the time of the decompression, "the
Summary and Discussion 501
excess pressure on the brain and the spinal cord from escaping
rather rapidly by the narrow passages through which the blood
leaves these organs:" and hence the congestions, or rather the
nervous compressions. This error in physics really does not de-
serve refutation.
On this subject M. Bouchard has conceived an idea worthy
of attention. It might be the sudden expansion of the intestinal
gases, originally compressed, which would suddenly expel the
blood contained in the abdominal viscera, would drive it into the
general circulation, and produce the congestions and the hemor-
rhages in the nervous organs (page 486). I confess that I cannot
admit that an expansion of gas, in a canal open at both ends, when
dealing with walls as extensible as the diaphragm and the ab-
dominal muscles, can expel the blood from the liver, the spleen,
etc., so violently as to produce such - disturbances.
Another explanation of the symptoms of decompression has
been suggested by M. Bucquoy, and prompted by the lectures of
Professor Rameaux, of Strassburg (page 459). Under the effect
of pressure, the gases of the blood would increase in quantity, the
oxygen following Dalton's Law, the nitrogen and the carbonic acid
following a lessened progression, "since they are not drawn in in
the inspired air, but engendered by the physical phenomena of
life." As a result, at the time of decompression, these gases tend
to be liberated again, just as "the carbonic acid escapes from
charged water, when the stopper is removed from the bottle con-
taining it." And M. Bucquoy mentions, to support this hypothesis
so probable in its general features, the emphysemas observed at
Douchy, the cure of muscular swellings by recompression, and a
very interesting observation which we have reported in full (page
460)
F. Hoppe, as we have seen, had already had the same idea; but
he based it only on experiments made on decompression by the
pneumatic machine, and brought no personal observation to sup-
port his hypothesis (page 455) .
The idea of M. Bucquoy was accepted by M. Frangois, who,
however, seems not to have had a very clear understanding of it,
because he speaks of "an amalgamation of the cellular tissue with
the air from the blowers, like that of mercury with hog's lard"
(page 456) , and by all the authors who followed him, Vivenot (page
435), Panum (page 480), M. Gavarret (page 482), M. Leroy de
Mericourt (page 483), etc.; M. Foley alone did not believe in it
(page 463) . M. Bouchard (page 484) , M. Gal (page 486) , and others
502 Historical
admit both the visceral congestions and the escape of the free gases
from the blood.
But no one has seen this escape, since no experiment has been
made. And what are these free gases? The three gases of the
blood and especially the oxygen, as M. Bucquoy indicates? Nothing
proves it; how can we believe that the oxygen, which combines so
easily with the tissues, can become gaseous again, and present a
serious, unconquerable obstacle to the circulation of this blood
which usually absorbs it so rapidly, and into which one can inject
it in large quantities without danger? Then how does the gas act
when it is freed? By obliterating the vessels? By causing hemor-
rhages? And how can it be that the symptoms are only the excep-
tion, even above four atmospheres? Could one not deny the truth
of the hypothesis itself, by maintaining that, if it must be admitted,
all the workmen decompressed at the same time should have their
blood like the charged water which escapes from the uncorked
bottle of which M. Bucquoy speaks, and should consequently be
stricken simultaneously?
We see, although it is probable a priori, and true as stated in
advance, the theory of free gases is far from being proved today.
Even for those who expressed and supported it, it is mingled with
other theories, and nothing very definite is evolved from the sum-
mary which we have just made.
Part II
EXPERIMENTS
Chapter I
CHEMICAL CONDITIONS OF THE DEATH
OF ANIMALS SUBJECTED TO DIFFERENT
BAROMETIC PRESSURES IN CLOSED
VESSELS
The numerous researches I formerly made on the final composi-
tion of the air contained in closed vessels in which animals were
kept till death1 decided me to begin the study of the influence
exerted on living organisms by modifications in the barometric
pressure, by analyzing the air which had become incapable of
supporting life in consequence of confinement, when this air is
subjected to pressures differing from the normal pressure.
A certain number of preliminary experiments, details of which
it would be useless to give here, had already given me the idea
that the principal, if not the sole cause of this influence, of which
aeronauts on one hand and men in diving apparatus on the other
present the most striking examples, was the different composition
of the gases contained in the blood, as a result of the different
pressures. It seemed, therefore, that the shortest and best way of
settling the question would be to begin by installing and operating
the apparatuses necessary for studying these gases of the blood.
However, I gave up this idea, though it seemed the simplest, and
determined to attack the problem by the indirect method of study-
ing the confined air; for this I had two reasons. In the first place,
I thought that I should thus find some new ideas on the question
of asphyxia, in which I had long been interested; secondly, the
problem which I was undertaking to solve seemed to me to present
such apparent complexity that I thought it best not to go straight
to what it seemed a priori should give me the general solution for
fear of being too quickly satisfied, and letting escape certain ele-
ments which perhaps were very important. I hoped, if I may be
505
506 Experiments
permitted this comparison, that in going across lots instead of
following the highway, I should find out something useful and
strange. The reader may judge whether my hope was deceived;
I merely wish to clear myself in advance of the charge of lacking
logic which might appear well founded, without daring never-
theless, in spite of my great desire to do so, to declare that this
indirect, and as it were oblique approach should be in many cases
adopted as the general method of research.
Now that this first question was given, I had to consider it from
all its points of view, and they are numerous. I could first consider
animals of the same species dying in closed receptacles under
pressures higher or lower than the normal barometric pressure. 1
could next compare to each other animals of different species in
similar barometric conditions. Finally, I must examine the action,
under different pressures, of respirable media the chemical com-
position of which differed from that of atmospheric air, because
this last consideration, applied to the theory of asphyxia, had given
Claude Bernard data of great interest.
I therefore adopted these various points of view, and I shall
give an account successively of the results which experimentation
gave me. I shall begin with the study of ordinary air and end with
that of air of different composition, and in both cases I shall take
up first decreased, then increased pressure. Each part of my
research will furnish the text of individual discussions; but it is
clear that general conclusions can be drawn only from their
simultaneous study, since the different data will so complete each
other and will be so intermeshed, so to speak, as to lead to a general
result which even now I can state in this rather paradoxical form:
pressure in its greatest variations, for example, from 10 centimeters
of mercury to 20 atmospheres, when these variations are made
with sufficient slowness, acts on living beings not as a direct
physical agent, but as a chemical agent changing the proportions
of oxygen contained in the blood, and causing either asphyxia,
when there is not enough of it, or toxic symptoms when there is
too much. It is upon the demonstration of this truth that all the
experimental data, the details of which I shall now give, converge.
Death in Closed Vessels 507
Subchapter I
PRESSURES BELOW ONE ATMOSPHERE
1. Experimental Set-Up.
The apparatus with which I made my experiments on the com-
position of the confined air in which animals die under pressures
less than one atmosphere, is very simple.
On a table four glass discs are fixed, mounted on copper plates
like those of pneumatic machines (Fig. 15) A, so that four experi-
ments can be carried on side by side. Since the four parts of the
apparatus are absolutely alike, only one need be described.
The disc is pierced in the center by an orifice through which
passes a lead tube topped with a movable cap B, which will prevent
the animal from being moved by the air suction. This tube leads to
a cross-pipe CC, which communicates with a suction pump oper-
ated by a steam engine; a cock D permits or cuts off communica-
tion. Between the cock and the mouth B extends a long glass
tube with two bends EFGH, which contains mercury. It is clear
that when the bell-jar I is fixed on disc A and the suction pump
is set in motion, the mercury will rise in the closed arm of the
glass tube, and that the difference between the levels tin' meas-
ured on the divided rule K will show exactly the amount of
decompression; e is a bulb intended to hold the mercury which
a piston stroke that was too strong might suck into the lead tubes.
The bell- jar I ends in a neck closed with a rubber stopper through
which pass a thermometer L and a cock M; the lower extremity of
the latter has a rubber tube, so that the air, which is extracted
by the process I shall explain in a moment, comes from the middle
of the bell- jar.
If these experiments are to give a satisfactory result, the ap-
paratus must be hermetically sealed and must keep exactly the
degree of vacuum to which it has been brought; the least opening,
permitting a little air to enter, may be the cause of serious errors,
as I found to my expense. To obtain the necessary hermetical
sealing, I immersed in water all the cracks through which the air
might enter. And therefore, the glass disc, on which the bell-jar
is fastened by tallow as usual, is surrounded by a projecting circle
of zinc N, into which water is poured; likewise, rubber capsules
O and P form a hydraulic seal for the adjusting of the cock M
and the manometric tube E; the cocks D and Q are immersed in
water in the receptacle R and the zinc gutter SS'. This device
insures that, if the closing was not perfect, water would enter
508
Experiments
instead of air, which would be a danger signal and show the place
where the apparatus was faulty.
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The animals placed under the bell-jar can be kept at a specified
height by means of a screen T, if it appears necessary.
When everything is ready, the pump is started, and the reader
will easily understand how one can, by varying the opening of
the cock M, diminish more or less rapidly the pressure in the
Death in Closed Vessels 509
bell-jar, while maintaining a current of pure air. This precaution,
as will be seen later, permits animals to become accustomed to a
certain degree to rather low pressures, which they seem unable to
endure at first. When I needed diminutions of pressure which
the pump could not give me, as soon as it stopped working, I
closed cock D (cock M having been closed some time before) and
put cock M in communication with an ordinary air pump by a
thick rubber tube, being able in this way to secure a vacuum
of about 1 cm. However, I rarely needed to resort to this procedure.
Now I must explain how I procured for analysis at a given
moment, especially after the death of the animal, a certain quantity
of the air contained in the bell-jar.
For this purpose I used the little model of mercury pump con-
structed by MM. Alvergniat. I think I should give here a descrip-
tion of this instrument which will be mentioned often in this work.
The mercury pump (Fig. 16) consists of a barometric tube
whose chamber A forms a large bulb and has on top a cock R,
which I shall discuss shortly, the cock being surmounted by a
little mercury bowl C. The barometric tube is connected below
by a very thick rubber tube with a reservoir B, whose capacity
exceeds a little that of chamber A. This reservoir is fixed on a
piece of wood which can slide up or down in a double groove by
means of a system of gears whose arrangement the figure shows.
The whole operation of the apparatus really depends on the
different positions of cock R. This is a three-way cock; the glass
ring in which it turns communicates by three orifices with the
barometric chamber, the mercury bowl, and the lateral tube lead-
ing to the exterior.
The cock itself is pierced by two channels meeting at right
angles. It is easy to understand the significance of its different
positions, which are represented above at the left in Figure 16.
In 1, all communication is cut off, and the barometric chamber is
hermetically closed; in 2, communication is made between the
chamber and the mercury bowl; in 3, communication between the
chamber and the lateral tube.
This glass cock, when properly greased, keeps the vacuum per-
fectly. However, for fear that air bubbles, penetrating between the
cock and its ring, should vitiate results, I had the whole enclosed
in a jacket of iron and rubber, which is kept full of water.
The last detail of construction is the graduated rule, which
allows the height of the mercury column to be measured, which is
often useful; the whole apparatus is mounted on a wooden case
510
Experiments
equipped with casters and supporting screws and surrounded by
ledges intended to catch the mercury which often falls and would
be lost in considerable quantity during the different operations.
It is clear that by pouring mercury into reservoir B previously
set at its highest point, and bringing cock R to position 2, one can
expel the air contained in the barometric tube and its chamber
Fig. 16 — Mercury pump set up for the extraction of the gases of the blood.
A. Barometric chamber. B. Movable bulb, in communication with
A by rubber and glass tube. C. Mercury bowl with graduated
tube to collect gases. R. Three-way cqck which can completely
close the barometric chamber (position 1), or connect A with C
(position 2), or A with D (position 3).,
Death in Closed Vessels 511
and replace it by mercury, which then rises into the bowl C. If
then the cock R is closed (position 1) and the reservoir B is set
at the bottom of the groove, the mercury will fall in the tube and
remain at 76 cm. above the level of reservoir B; in other words,
there will be a barometric vacuum in chamber A. If then cock R
is turned (position 3) to put this chamber in communication with
the lateral tube which, in our figure, communicates with a system
of sleeve and balloon serving only for the extraction of blood gases,
a certain quantity of outside air is introduced, and the mercury
descends in the barometric tube. When the cock is closed (position
1), a quantity of this air is imprisoned; and if any is needed for an
analysis, one needs only to raise reservoir B and shift cock R to
position 2, and the air driven out by the rising mercury passes
through the little bowl C and enters the inverted tube which is
ready to receive it.
The invention of the mercury pump is usually attributed to
German technicians, and with the love of foreign advertising cus-
tomary to us we often decorate this instrument with the name of
"Geissler pump." The truth is that the invention belongs in prin-
ciple to M. Regnault. Long ago this famous professor of the Col-
lege de France invented a similar pump, equipped with a three-way
cock, which is the most important part of the instrument. But
instead of using a movable reservoir, since at that time rubber
was seldom used in the construction of- apparatuses, he put his
barometric tube in communication with two reservoirs, one above
and one below; this required, of course, a rather complicated sys-
tem of tubes and cocks. But the principle was the same, and the
addition of a rubber tube is certainly not of sufficient importance
to make us forget the real inventor.
And now it is very simple to understand how this instrument
can be applied to extracting the air contained in the bell-jars of
the apparatus represented in Figure 15. The only thing necessary
is to add to the lateral tube, which in Figure 16 communicates with
the balloon D, a rubber tube which can sustain a vacuum, and
which covers with its other end the cock M, which is at the top
of the bell- jar in which the experimental animal is contained.
When this cock has been closed and a vacuum has been made in
chamber A, I put cock R in position 3 so as to exhaust the air from
the rubber tube S; then close cock R (position 1), raise reservoir
B as high as possible, place the cock in position 2, and the air
passes out over the mercury in the bowl, over which the tube has
not yet been inverted. When this procedure has been repeated
512 Experiments
two or three times, a complete vacuum has been made in the whole
apparatus, including the rubber tube, as is proved by the sharp
click of the mercury (the "mercury hammer") against the closed
cock R, the force of which must be lessened by raising the reservoir
carefully.
When this has been done, and when reservoir B has been
lowered as far as possible and cock R has been placed in position
3, I open the communicating cock between the bell-jar from which
I wish to take an air sample and the rubber tube. Evidently, a
certain quantity of air from the bell-jar rushes out and fills bulb A. "
As a precaution, I let out this air for fear that the vacuum has not
been perfect in the lateral tube and the barometric chamber, and
begin the same procedure again. But this time I invert over bowl
C a graduated tube full of mercury, and the gas which has been
compressed in chamber A as a result of raising reservoir B comes
into the tube bubble by bubble through a passage carefully con-
trolled in shifting from position 1 to position 2 of the cock. The
gas thus collected can easily be removed for analysis.
The analysis is made over the mercury bowl by means of a
solution of potash to absorb the carbonic acid, then by another
solution of pyrogallic acid to absorb the oxygen. The differences
of level, measured in the graduated tube, by a very simple calcula-
tion give the percentage composition of the gas. This method of
analysis, extremely convenient and rapid when one is careful to
shake the tube vigorously, especially after the introduction of the
pyrogallic acid, seems to me superior to any other.
A German physiologist, who visited my laboratory one day, re-
proved me severely for measuring the differences of level without
using a cathetometer; for not using the Bunsen method, by bubbles
of potash and phosphorus, which gives more exact results; for not
having deducted the value of the column of liquid, which lessens by
two or three centimeters of water the tension of the air contained
in the graduated tube; and for not having taken into account the
small quantity of oxide of carbon which may be formed during
the absorption of oxygen by the pyrogallate. I should not mention
these petty criticisms here if they did not furnish a very character-
istic example of a common mistake in method from the other side
of the Rhine, which affected pedants would like to import into
France. I have already had the opportunity to express my opinion
of this useless and dangerous- search for false exactness. I mention
• it in reference to the present analyses merely to state that the
causes of errors pointed out affect only the third decimal, which I
Death in Closed Vessels 513
took care never to record. The reader will see, when I discuss the
results of the experiments, how circumstances which it is impos-
sible to foresee and very often impossible to explain can cause
variations in the numbers furnished by the analyses in the first
decimal or even in the units. Worrying about a third decimal
would be silly.
These observations refer, of course, to all the gas analyses enu-
merated in the present work, whether of compressed or expanded
air, gases extracted from the blood, etc.
2. Experiments.
A. Experiments on Birds.
These are much the most numerous.
Sparrows (house sparrow, Fringilla domestica, Lin. and moun-
tain sparrow, Fringilla montana, Lin.) were chiefly used in these
experiments and in those relating to increased pressure.
I will begin by giving details of experiments in which death
in confined air took place at normal pressure. They will serve as
comparison for the others.
Experiment I. March 21, temp. 15°. House sparrow, vigorous,
weighing 31 gm. Placed on the mercury reservoir in a bell measuring
1 liter; a cork ring separates it from the mercury.
Entered at 1:40; died at 2:45; duration of life, 1 hour 5 minutes.
Composition of lethal air : O2 3.0; CO 14.8,
Addition of oxygen remaining and carbonic acid formed:
CO + O* = 17.8
Proportion of carbonic acid formed to oxygen disappeared:
CO 14.8
= = 0.82
O 17.9
Experiment II. March 18. House sparrow.
Bell of 1.9 liters. Entered at 1:10, dead at 3:05. Final decompres-
sion results from absorption of 2.3 cm. There is no bloody spot on
the head.
Lethal air : O 4.2; CO- 14.6
CO2
CO + O = 18.8; = 0.87
O2
Experiment III. July 20; temp. 24°. House sparrow.
Bell of 1.3 liters. Entered at 3:15, normal pressure. Not dead at
6:15, dies about 7.
Lethal air : O2 3.3; CO2 16.0
CO
CO + 02 = 19.3; = 0.86
O
514 Experiments
I now come to the experiments made with the apparatus pic-
tured in Figure 15.
Experiment IV. March 24, temp. 15°, pressure 75 cm. House spar-
row. Bell of 5 liters.
Entered at 2:04. Began current of air with steam engine, cock M
being open. At 2:10, decompressed 10 cm.; at 2:12, 15 cm.; at 2:14, 20
cm.; at 2:17, 25 cm.; at 2:20, 30 cm.
The cock is closed and the decompression continued. At 2:23,
32 cm.; at 2:30, 40 cm.; at 2.37, 52 cm.; actual pressure 23 cm.
Cock D is then closed. The pressure is perfectly maintained at
23 cm. with absorption of about 1 half-centimeter. The bird dies at
3:55, and therefore lived in 5 liters of air at 22.5 cm., which represent
about 1.4 liters at normal pressure, for 1 hour 35 minutes.
Composition of lethal air: O 10.3; COa 7.5.
CO*
CO2 + O* = 17.8; = 0.70.
O2
Experiment V. March 25; temperature 15°; pressure 75 cm. House
sparrow. Bell of 3.200 liters.
Entered at 1:50; current of air. At 1:53; pressure down 10cm.;
at 1:59, 21 cm.; at 2:02, 33 cm.; at 2.05, 45 cm.; cocks closed: actual
pressure 29 cm.
Lethal air: O2 9.3; CO2 11.2.
CO
CO2 + O = 20.5; = 0.96
O2
Experiments VI to IX, simultaneous. May 6; temperature 16°;
pressure 76.4 cm. Vigorous male mountain sparrows.
VI. Bell of 2.5 liters.
Entered at 3:42. Left at normal pressure. At 6 o'clock, very sick;
respiratory rate 128; at 6:25, respiratory rate 120. Dies at 7:05. Lived
three hours 23 minutes.
Lethal air: O* 3.5; CO2 14.6.
CO=
CO + O2 = 18.1 ; = 0.84
O2
VII. Bell of 3.2 liters.
Entered at 3:42. Current of air; at 3:55, pressure down 6 cm.; at
4 o'clock, 16 cm.; at 4:04, 21.4 cm. Cocks closed. Actual pressure 55 cm.
At 4:19, fairly calm, respiratory rate 120; at 5:08, respiratory rate
116; at 6 o'clock, respiratory rate 112, does not seem sick; at 6:25,
respiratory rate 108, still well enough. Dies at 8:35.
Lived 4 hours 31 minutes, in 3.2 liters of air at 55 cm., which
represent 2.3 liters at 76 cm.
Lethal air: O2 4.5; CO2 14.4.
CO*
CO* + O2 = 18.9; = 0.84
02
Death in Closed Vessels 515
VIII. Bell of 5 liters.
Entered at 3:42: current of air. At 3:55, pressure down 8 cm.; at
4 o'clock, 16 cm.; at 4:04, 19 cm.; at 4:07, 40 cm. Actual pressure 36.4
cm. Cocks closed.
At 4:19, respiratory rate 150, calm; at 5:08, respiratory rate 126;
at 6 o'clock, very sick, respiratory rate 128; at 6:25, respiratory rate
150; dies at 7:10.
Lived 3 hours in 5 liters of air at 36.4 cm., which represent 2.4
liters at 76 cm.
Analysis lost.
IX. Bell of 11.5 liters.
Entered at 3:42: current of air. At 3:55, pressure down 14 cm.; at
4 o'clock, 29 cm.; at 4:04, 38 cm.; at 4:07, 52 cm.; at 4: 11, 59 cm. Cocks
closed. Actual pressure 17.4 cm.
Very sick afterwards. At 4:19, respiratory rate 140; at 4:22, dies
with convulsions. Lived 11 minutes.
Lethal air: O? 19.6; CO? 0.6.
Experiments X to XII, simultaneous. May 11; temperature 16°;
pressure 75.5 cm.
X. Male mountain sparrow. Bell of 2.2 liters.
From 3:20 to 3:22 the pressure is dropped suddenly to 20 cm.
Immediately, collapse of bird, and death at 3:24, after convulsions. It
was not thought necessary to take an air sample for analysis.
The left heart contains dark blood; no gas in the blood.
XI. House sparrow. Bell of 3.2 liters.
Brought from 3:15 to 3:17 to a pressure of 24.5 cm. Collapses
a moment, then recovers very well. Dies at 3:52. Lived 38 minutes
in a bell the capacity of which, when reduced to a pressure of 76 cm.,
represented 1.03 liters of air.
Lethal air: 0* 12.8; CO? 6.2.
CO?
CO? + O? = 19.0; = 0.76
O?
XII. House sparrow. Bell of 4.6 liters.
Brought in a few minutes to a pressure of 34.3 cm.; hardly seems
to notice it. Cocks closed at 3:09.
At 4:50, very sick, but still on its feet. Dead at 5:45. Lived 2
hours 34 minutes in a quantity of air representing 1.89 liters at 76 cm.
Lethal air: O? 8.2; CO? 10.8.
CO?
CO? + O? = 19.0; = 0.85
O2
Experiments XIII to XV, simultaneous. May 24; temperature 17°;
pressure 76.5 cm. House sparrows.
XIII. Bell of 2.5 liters.
Entered at 3:31: current of air. At 3:35, actual pressure 37 cm.:
cocks closed. The bird does not seem uncomfortable.
Dies at 5:20. Lived 1 hour 45 minutes in a quantity of air which repre-
516 Experiments
sents 1.22 liters of air at 76 cm. Slight absorption of about Vz cm. of
mercury; the final pressure therefore is only 36.5 cm.
Lethal air: O 7.2; CO 11.5.
CO.'
CO + O = 18.7; = 0.84.
o
XIV. Bell of 3.2 liters.
Begun at 3:24. At 3:27, actual pressure of 28.3 cm.; the bird does
not fall; the cocks are closed.
Dies at 4:56. Lived 1 hour 30 minutes in a quantity of air corre-
sponding to 1.19 liters; absorption of about Vz cm.; the actual pressure
therefore is 27.8 cm.
Lethal air: O 7.9; CO 10.3.
CO-
CO.- + O* = 18.2; = 0.79.
O
XV. Bell of 4.6 liters.
Begun at 3:10. At 3:15, drop in pressure of 51 cm., the bird falls.
At 3:17, drop of 55 cm.; cocks closed; actual pressure, 21.5 cm.
At 3:25, the bird rises and appears much less uncomfortable. At
4:42, fairly violent convulsive struggling. Last movement at 4:55.
Lived 1 hour 40 minutes in a quantity of air corresponding to 1.3
liters.
Lethal air: O 11.8; CO 7.
CO
CO- + O; = 18.8; = 0.77.
O
Experiments XVI to XIX, simultaneous. May 31; temperature
19°. Pressure 75.8 cm. Young, but vigorous sparrows.
XVI. Bell of 5 liters.
Begun at 3:43. At 3:53, the actual pressure is only 19.7 cm. The
cocks are closed.
The bird has remained motionless; but when the pressure has
dropped 45 to 50 cm.; it becomes uneasy, then sick. At the moment
when the cocks are closed, it seems likely to die soon. But about 4
o'clock it is considerably better.
Dead at 5:30. Lived 1 hour 45 minutes in a quantity of air corre-
sponding to 1.30 liters.
At 5:42, the rectal temperature is 25.6°; there is no rigor mortis.
At 5:55, the temperature is 22.8° and there is rigor, which therefore
came in less than 25 minutes.
Lethal air: O? 12.9; CO? 7.0.
CO?
CO- + O = 19.9; = 0.87.
O
XVII. Bell of 4.6 liters.
Begun at 3:45. As soon as it was under the bell, the bird struggled
continuously; the same thing was true during the first part of the
Death in Closed Vessels 517
decompression; at about, a drop of 40 cm., it grew calm, began to pant
and grew sicker and sicker. At 3:53, the pressure was only 20.8 cm.
Cocks closed. The bird was very sick, struggled violently and convul-
sively, and died at 3:55, that is, in 2 minutes, in a quantity of air
corresponding to 1.27 liters.
At 4:15, its rectal temperature was still 31.6°, and the rigor mortis
was very pronounced.
Lethal air: O 20.5; CO 0.3.
XVIII. Bell of 3.2 liters.
Begun at 3:47. The bird struggled as did the preceding one, then
grew calm at a drop of about 40 cm. and immediately became quite
sick. At 3:51, the pressure was only 27.8 cm.; cocks closed.
The bird was then very sick, and seized by vomiting. But he
quickly recovered and was fairly well about 4 o'clock. At 6:30, died
without convulsions. He therefore lived 2 hours in a quantity of air
corresponding to 1.15 liters.
At 6:42, his rectal temperature was 21.4°; no rigor mortis. At 6:45,
21°; beginning rigor. At 6:47, that is, after 17 minutes, complete
rigor; temperature 20.5°.
Lethal air: O- 8.5; CO 10.9.
CO
CO + O- = 19.4; = 0.88.
O
XIX. To examine the natural course of the decrease of temper-
ature and the onset of rigor mortis, at 5:07, I cut off the head of a
sparrow like the preceding. The rectal temperature was 42.8°; the
reflex movements disappeared immediately; the eye lacked sensitivity,
although the beak still opened spontaneously several times. After 3
minutes, the temperature was 41.7°; after 15 minutes, 35.5°; after 23
minutes, 32.9°; after 38 minutes, 29.5°. At that time there was no rigor
mortis yet.
Experiments XX to XXIV, simultaneous. June 3; temperature
20°; pressure 76.3 cm. House sparrows.
These experiments were made with the purpose of finding out
whether the dimensions of the bells have a considerable effect upon
the composition of the lethal air when the decompression is the same
in all.
XX. Bell of 11.5 liters.
Begun at 2:51. At 2:57, the pressure is only 30.8 cm. The sparrow
has not struggled, he is hardly sick. Cocks closed.
At 3:05, he staggers and vomits, but recovers rather quickly; at
5:40, a little sick; at 9:30, very sick: air is extracted with the mercury
pump, which decreases the pressure about 1.5 cm. more; the bird's
discomfort seems increased immediately.
Dies at 9:50; lived 6 hours 53 minutes in a bell the capacity of
which, reduced to normal pressure, would represent 4.66 liters, or 1
hour 28 minutes per liter.
The rectal temperature, taken at 9:55, is 28.4°; there is no rigor
mortis, but it is present at 10:05, the temperature being 26.7°.
518 Experiments
The air sample taken at 9:30 contained 0-> 8.8; CO 9.4.
The lethal air contained O* 8.3; CO 9.8.
CO
CO + O. = 18.1 ; = 0.78.
O
XXI. Bell of 7 liters.
Begun at 2:51. At 2:55, pressure is 30.3 cm. The bird, which has
been struggling a good deal, is quite sick, and has difficulty in stand-
ing up. Cocks closed. At 5:25, very sick.
Dies at 7:20. It therefore lived 4 hours 25 minutes in a quantity
of air corresponding to 2.79 liters, or 1 hour 34 minutes per liter.
At 7:30, its temperature is only 25°; no rigor; at 7:40, found stiff.
Lethal air: O 8.2; CO* 10.1.
COs
CO2 + O2 = 18.3 ; = 0.79.
O
XXII. Bell of 5 liters.
Begun at 2:47. Struggles a great deal. At 2:51, the pressure is
only 26.1 cm. The bird is very sick and crouched against the rim of
the bell.
Dies at 2:53. At 3:10 is very stiff. Its temperature is 34.7°.
Lived 6 minutes. No air sample taken.
XXIII. Bell of 5 liters.
Begun at 3:20. Struggles a great deal. At 3:24, the pressure is
30.3 cm.; the bird does not seem sick; cocks closed. At 5:25, very sick.
The time of death was not noted.
Lethal air: O 8.3; CO' 10.3.
CO
CO- + O = 18.6; = 0.81.
O
XXIV. Bell of 2.5 liters.
Begun at 2:51. At 2:59, the pressure is 30.5 cm. Struggled a
great deal, vomits, but does not fall. Cocks closed.
About 3:05, a little struggling. Dies at 4:30.
At 4:50, temperature 27°; pronounced rigor. Lived 1 hour 31 min-
utes in the bell the capacity of which corresponds to 1 liter.
Lethal air: O- 10; CO 10.4.
CO*
CO= + O* = 20.4; = 0.95.
O
The average of the four experiments in which the air was ana-
lyzed is for the pressure of 30.5 cm.: O2 8.7; CO2 10.1.
Experiments XXV to XXVIII, simultaneous, made with the same
purpose as the preceding ones. June 8. Temperature 20.5°; pressure
76 cm. House sparrows.
Death in Closed Vessels 519
XXV. Bell of 11.5 liters.
Begun at 3:45. At 3:53, the pressure is 24.2 cm. Struggled; some-
what sick; lying down, yawns frequently; cock closed.
At 4:15, gets up on its feet; at 6 o'clock, in fair condition; at 7:30,
somewhat sick; found dead at 9:30.
Therefore lived about 5 hours in a bell the capacity of which
represents 3.66 liters; or about 1 hour 22 minutes per liter.
Lethal air: O 13.7; CO* 5.4.
CO,
CO, + O, = 19.1 ; = 0.75.
O,
XXVI. Bell of 7 liters.
Begun at 4 o'clock. At 4: 10, pressure of 24.2 cm. Struggled a great
deal; has convulsions and seems near death. Cocks closed.
At 4:15, gets up on its feet; at 4:30, very lively, struggles a good
deal at 5 o'clock, becomes sick; at 6 o'clock, drowsy; at 6:20, dies after
violent convulsive struggling.
Lived 2 hours 10 minutes, in a quantity of air corresponding to
2.22 liters; or 58 minutes per liter.
At 6:32, rectal temperature 30.3°, is not quite stiff; at 6:45, stiff,
temperature 26.5°.
Lethal air: O, 12.6; CO, 7.0.
CO,
CO, + O, = 19.6; = 0.84.
O,
XXVII. Bell of 5 liters.
Begun at 4:15. At 4:21, reached a pressure of 24.2 cm.; struggled
at first, then grew calm at a pressure drop of about 42 cm. as the pre-
ceding ones did; did not fall. Cocks closed.
At 4:22, staggers, vomits, crouches down; but soon gets up and
seems fairly well.
At 5:30, very sick; at 6:10, dies. Lived 1 hour 50 minutes in a bell
the capacity of which corresponds to 1.55 liters of air; or 1 hour 10
minutes per liter.
At 6:21, stiff; temperature 27.2°.
Lethal air: O, 11.6; CO, 7.8.
CO,
CO, + O, = 19.4; = 0.84.
0*
XXVIII. Bell of 2.5 liters.
Begun at 4:16. At 4:26, the pressure is 24.2 cm. Struggled, but
does not seem in danger.
Dies at 5:30; lived 1 hour 4 minutes in a quantity of air corre-
sponding to 0.79 liters; or 1 hour 21 minutes per liter.
At 5:50, found stiff; temperature 27.5°.
Lethal air O, 12.6; CO, 5.9.
CO,
CO, + O, = 18.5; = 0.71.
O,
Average of the four experiments: O, 12.6; CO, 6.5.
520 Experiments
Experiments XXIX to XXXII, simultaneous. June 10. Tempera-
ture 21°; pressure 75.5 cm. House sparrows.
XXIX. Bell of 11.5 liters.
Begun at 2 o'clock. Struggles a great deal; at 2:08, a pressure drop
of 40 cm.; grows calm for a moment, then struggles again. At 2:12,
the pressure drop is 47 cm.; no longer moves; a little out of breath.
At 2:16, drop of 55 cm.; more out of breath, vomits. At 2:17, the pres-
sure is only 17.5 cm. Cocks closed.
The bird is breathing with great difficulty, and remains lying
down. It dies with convulsions at 2:20, that is, after 3 minutes. The
air hardly contains traces of carbonic acid.
XXX. Bell of 11.5 liters.
Begun at 2:45; struggles a good deal. At 2:50, the pressure is
decreased 42 cm.; the bird grows calm; at 2:53, a decrease of 44 cm.;
staggers, vomits, but begins to struggle again. At 2:56, a decrease of
52 cm.; suffers greatly. At 3:05, a decrease of 56 cm.; falls and seems
about to die. A little air is admitted until the decrease is only 49
cm. At 3:08, since the bird seems to have recovered fairly well, the
decompression is resumed; at 3:11, a decrease of 58 cm.; convulsive
struggling, death imminent; we return to a decrease of 49 cm. At 3:16,
fairly well recovered; at 3:18, a decrease of 56.5 cm.; not too sick.
Cocks closed.
At 3:35, the bird vomits; at 3:55, as it is not too sick, the decom-
pression is carried to 57.5 cm.; that is, an actual pressure of 18 cm.; it
immediately becomes uneasy, but death does not occur until 4:30.
Therefore it lived 1 hour 4 minutes in a quantity of air represen-
ting 2.70 liters; or 23 minutes per liter.
Lethal air: Cb 17.7; CO2 2.8.
CO
CO-» + 0= = 20.3; = 0.87.
O
XXXI. Bell of 1.9 liters.
Begun at 3:35. At 3:45, the pressure is 41.3 cm. Cocks closed.
Dead at 5:23; at 5:30, rectal temperature 28°.
Lived 1 hour 45 minutes in a bell corresponding to 1.03 liters;
or 1 hour 40 minutes per liter.
Lethal air: O2 6.5; CO 12.9.
CO
CO + O2 = 19.4; = 0.89.
o=
XXXII. Bell of 1.5 liters.
Begun at 3:35. At 3:45, a pressure of 48.5 cm. Closed.
Dead at 5:10. At 5:20, temperature 24.8°. Lived 1 hour 25 min-
utes; the capacity corresponded to 0.92 liters, or 1 hour 32 minutes
per liter.
Lethal air: O 5.2; CO-* 14.1.
CO*
CO* + Os = 19.3; = 0.89.
Oa
Death in Closed Vessels 521
Experiments XXXIII -XXXIV, simultaneous. June 14. Tempera-
ture 22°; pressure 76.5 cm. House sparrows.
XXXIII. Bell of 3.2 liters.
Begun at 4:16; moderate agitation. At 4:21, pressure decrease of
43 cm.; vomits, is tired; at 4:22, pressure is 23 cm.; very sick. Cocks
closed.
At 4:26, still on its side; rises later. Dies at 5:20. At 5:31, tem-
perature 32°, not stiff. At 5:40, 30.7°.
Lethal air: O2 11.2; CO* 7.6.
CO,
CO* + O2 = 18.8; == 0.78.
O2
XXXIV. Bell of 2.8 liters.
Begun at 4:19; moderate agitation. At 4:25, pressure of 25 cm.;
vomits. Cocks closed.
Not so sick as the preceding bird. At 4:27, pressure dropped to
24.5 cm.; panting hard. At 5:27, dies with convulsions. At 5:40, the
temperature is 31.6°; at 5:52, it is 29.4°. Lived 1 hour 2 minutes in the
equivalent of 0.9 liter of air; or 1 hour 7 minutes per liter.
Lethal air: O2 11.3; CO2 8.1.
CO2
CO2 + 02 = 19.4; = 0.84.
O2
Experiments XXXV - XXXVI, simultaneous. July 26. Temperature
22°; pressure 76 cm. House sparrows.
XXXV. Bell of 2.25 liters.
Brought in a few minutes to a pressure of 55 cm. Cocks closed
at 1:45.
Dead at 3:25. Therefore lived 1 hour 40 minutes in a bell the
capacity of which represented 1.6 liters at normal pressure; or 1 hour
3 minutes per liter. At 3:33, rectal temperature 28°.
Lethal air O2 4.6; CO2 13.4.
CO'
CO2 + O2 = 18.0; = 0.81.
O2
XXXVI. Bell of 3.2 liters.
Brought to a pressure of 47 cm. Cocks closed at 2 o'clock. Dead
at 3:53. Lived 1 hour 53 minutes in a capacity equivalent to 2 liters;
or 57 minutes per liter.
At 4 o'clock, rectal temperature 27°.
Lethal air: O2 5.5; CO-' 12.4.
CO2
CO.- + 02 = 17.9; = 0.80.
O2
Experiment XXXVII. March 18. Pressure 76 cm.
House sparrow, placed at 1:45 under a bell of 3.2 liters. The pres-
sure is lowered to 38 cm. Dead at 3:15. A few spots in the cranial
522 Experiments
diploe, in the occipital region. Lived 1 hour 30 minutes in the equiva-
lent of 1.6 liters of air, or 56 minutes per liter.
Lethal air: O 8.2; CO? 11.6.
CO.
CO + O* = 19.8; == 0.91.
O2
I have purposely given in the preceding pages an account of a
great number of experiments so as to show what is indefinitely
variable in the phenomena and at the same time what stands out
as general in this variety, which defies both deceptive averages
and sham precision of decimals. Certainly, when a sparrow dies
under a bell at a certain pressure, the air of this bell has a com-
position which the best methods of modern chemistry could per-
haps permit us to determine to about one ten-thousandth. But
what would be the use of this precision when our experiments show
us that another sparrow exactly like the first, placed in apparently
identical conditions, dies with a composition of ambient air which
may differ from the first by 4 or 5 tenths of oxygen or carbonic
acid, or even more? It is evidently better to multiply experiments
to try to find the explanation of these differences and to adhere to
convenient methods of analysis which permit one to work rapidly.
But the height of absurdity — and this, unfortunately, is found
rather frequently in German work — is to claim to give to these
other methods an appearance of precision which they do not pos-
sess, carrying calculations to the second and third decimal and
even resorting to a table of logarithms to get more decimals. This
charlatanism of decimals which leads one to claim exactness for
the thousandths in a number which is wrong beyond the units, is
an illusion which must be avoided. Let us make our criticism
specific by applying it to the present case.
Let us imagine, in a tube graduated to tenths of cubic centi-
meters, inverted over the mercury bowl, our usual gaseous mixture
of nitrogen, oxygen, and carbonic acid. To avoid taking account
in the first determination of a convex mercurial meniscus and in
the other two of a concave aqueous meniscus, I first introduce into
the tube some drops of pure water, and try to determine the level.
Now admitting that the greatest precautions have been taken, it is
impossible to estimate the height of the liquid column with a closer
approximation than five hundredths. Let us suppose that I have
found that it is between 25.3 cc. and 25.4 cc; but I cannot be sure
whether it is 25.32 cc. or 25.37 cc, for example. I now add the
potash, shake it vigorously and repeatedly, and again plunge the
tube into the mercury to bring it to its original temperature.
Death in Closed Vessels 523
Again I make a supposition: the present level will be, let us say,
between 20.2 cc. and 20.3 cc. and I must choose between 20.23 cc.
and 20.28 cc. According to whether I take my meniscus level
higher or lower — and we know how difficult the estimate is for a
colorless liquid, without mentioning the fact that the meniscus
of pure water in a tube which is necessarily rather dirty is not
the same as the meniscus of a potash solution which wets the glass
perfectly, — there will have disappeared in an average quantity
of 25.35 cc. either 5.04 cc. or 5.14 cc. of carbonic acid, which gives
for the percentage composition in the first case 19.88 cc. per 100
(25.35 : 100 = 5.04 cc. : x = 19.88) ; and in the second case, 20.27 cc.
per 100 (25.35 : 100 = 5.14 cc. : x = 20.27) .
That is, without taking into account the cause of error due to
the operation itself, which here involves the second decimal, my
analysis, though made as well as possible by the volumetric method,
exposes me to an error which in this present , case may equal
0.39 cc. In other words, the first decimal can and must be con-
stantly vitiated in the necessary speed of the analyses.
It is with this consideration that we must examine all the
results of our analyses; and therefore no one will reproach me
for having prudently stopped at this figure which indicates exactly
the degree of precision which one can expect from this volumetric
method of analysis, any more than for not having used other
methods, when the experimental differences, over which we have
no control, are at least of the same order, as I said above.
With these reservations, let us examine the results of the ex-
periments which, in order to shorten tiresome reading, I have
grouped in a summarizing table, arranging them in the order of
the pressures.
If we examine Column 8, which gives the proportion of oxygen
remaining in the air which has become irrespirable, we see that
the numbers which it contains increase proportionately as the
pressure diminishes. This rule, however, has apparent exceptions,
as the table shows. But if we consider the results given by the
analyses of air which has become incapable of supporting life
made at the same pressure, we see that the exceptions mentioned
are of the same order as the differences which separated the re-
sults of these analyses. Thus at normal pressure, the proportion
of oxygen remaining varied between 3.0 and 4.2 per cent; similarly
at 24.2 cm., it varies between 11.6 and 13.7 per cent.
The general tendency of the phenomenon is shown still more
clearly in the curve represented by O, Figure 17. Here the pres-
524 Experiments
sures are measured on the axis of the abscissae, in increasing order,
and the quantities of oxygen are represented on that of the ordi-
nates. We shall see presently that this curve, if we set aside the
Fig. 17— Composition of confined air which has become lethal at pressures
below 1 atmosphere. O. Proportions of oxygen remaining. CO2.
Proportions of carbonic acid. CO'-f-O. Sum of oxygen consumed
and carbonic acid formed.
little irregularities of which we have spoken, takes a precise geo-
metric form, which is exactly a branch of a hyperbola.
The proportion of carbonic acid produced naturally follows an
opposite course, as is shown by curve C02, which represents its
modifications.
Therefore, the weaker the pressure, the less the confined air
needs to be altered in its chemical composition to become irre-
spirable. At very low pressures it becomes irrespirable even
though perfectly pure, for a reason which we shall give presently.
But the general fact which we have just mentioned is enough to
show that the carbonic acid given off in the confined space plays
no part in the death, since its proportion decreases progressively
Death in Closed Vessels
525
Table I
Q.CD
CJ
O
•o
CD
o <" 3
°-^T3 (D
02
■^ <u
c*l ti
Composition
d
coa
■si
■a
Zi Si
33
0 w
6 gl
al Z V
can, °
>>
UoJ
c
o
2 v
3^1
g Si 3
O Si Cfl
02*26
of lethal
air
d
+
d"
u
Oo
|h.m.
h.m.
co2
O, 1
1
I
15
76
1 115
1 5
3.0
14.8 1 3.0
17.8
0.82
2
II
15 | 76 1 1.9 | 1 55 | 0 57
4.2
14.6 | 4.2
18.8
0.87
3
VI
16
75
2.5 | 3 23
1 20
3.5
14.6
3.5
18.1
0.84
4
III
24
75
1.3 | 3 45
2*50
3.3
16.0
3.3
19.3
0.86
5
VII
16
55
3.2 | 4 31
1 57
4.5
14.4
3.2
18.2
0.84
6
XXXV
22
55
2.2-1 1 40
1 03
4.6
13.4
3.3
18.0
0.81
7
XXXII
21
48.5
1.5 1 1 25
1 32
5.2
14.1
3.3
19.3
0.89
8
XXXVI
22
47 | 3.2 | 1 53
0 57
5.5
12.4
3.4
17.9
0.80
9
XXXI
21
41.3 | 1.9 | 1 45 | 1 45
6.5
12.9
3.5 | 19.4
0.89
10
XXXVII
—
38 I 3.2 I 1 30 1 0 56
8.2
11.6
4.1
19.8
0.91
11
XIII
17 | 37 | 2.5 | 1 45 | 1 27
7.2
11.5
3.5
18.7
0.84
12
VIII
16 | 36.4 | 5 | 3 00 | 1 15
—
13
XII
16 1 34.3
4.6 | 2 34 | 1 21
8.2
10.8
3.7
19.0
0.85
14
XX
20 | 30.8
11.5 | 6 53 | 1 28
8.3
9.8
3.4
18.1
0.78
15
XXIV
20 ] 30.5
2.5
1 31 | 1 31
10.0
10.4
4.0 | 20.4
0.95
16
XXIII
20 | 30.3
5
1
8.3
10.3
3.3 | 18.6
0.81
17
XXI
20 | 30.3
7
4 25 | 1 34
8.2
10.1
3.2
18.3
0.79
18
V
15 j 29
3.2
9.3
11.2
3.5
20.5
0.96
19
XIV
17 | 28.3
3.2
1 30 | 1 15
7.9
10.3
3.0
18.2
0.79
20
XVIII
19 | 27.8
3.2
2 00 | 1 44
8.5
10.9
3.1
19.4
0.88
21
XXII
20 | 26.1
5
0 06 |
—
22
XXIV
22 | 25
2.8
1 02
1 07
11.3
8.1
3.6
19.4
0.84
23
XI
16 | 24.5
3.2
0 38
0 38
12.8
6.2
4.1
19.0
0.76
24
XXV
20 | 24.2
11.5
5 00
1 22
13.7
5.4
4.3 | 19.1
0.75
25
XXVI
20 | 24.2
7
2 10
0 58
12.6
7.0
4.0
19.6
0.84
26
XXVII
20 | 24.2
5
1 50
1 10
11.6
7.8
3.6
19.4
0.84
27
XXVIII
20
24.2 | 2.5
1 04
1 21
12.6
5.9
4.0
18.5
0.71
28
IV
15
23 | 5
1 35
1 08
10.3
7.5
3.1
17.8
0.70
29
XXXIII
22
23
3.2 |
11.2
7.6
3.4 | 18.8
0.78
30
XV
17
21.5
4.6 | 1 40
1 17
11.8
7.0
3.3 | 18.8
0.77
431
XVII
19
20.8
4.6 I 0 02
—
32
X
19
20
2.2
0 02
—
33
XVI
19 1 19.7 I 5
1 45 | 1 20
12.9
7.0
3.3
19.9
0.87
34
XXX
21
18
11.5
1 04 | 0*25
17.7
2.8
4.2
20.3
0.87
35
XXIX
21
17.5
11.5
0 03 |
— |
36
IX
16
17.4
11.5
0.11 |
1 avg
| lhr.
| 16 min.
19.6
0.6 | 4.5 | 20.2 |
|avg| I
| 3.5
| sxcept
exper
iments marked with
an as'te
risk
to minimum amounts. Furthermore, direct experiments, in which
this acid was largely absorbed by a solution of potash as rapidly
as it was formed, have shown that the composition of the lethal
air, from the point of view of its oxygen content, was not changed
at all. It is this content, or rather this lack of oxygen which is the
cause of death, and which we must consider carefully.
526 Experiments
It really seems very difficult at first glance to attribute death to
a lack of oxygen in experiments where 12, 15, or 17 per cent of
it remained in the air. But this difficulty disappears after suffi-
cient reflection.
Indeed, we know that when a bird dies at normal pressure in
confined air, this death is due (for the most part, at least; we shall
give a longer explanation later) to a lack of oxygen, or to speak
more exactly, to the too weak proportion, and more exactly still,
to the too weak tension of this gas in the ambient atmosphere.
This tension can be expressed at normal pressure precisely by the
figure which indicates the percentage. One may say, for example,
that at one atmosphere the tension of the oxygen of ordinary air
is 20.9; and likewise that the tension of the oxygen of confined air
which has become lethal varies somewhere between 3 and 4
per cent.
According to this, the tension of oxygen at a pressure lower
than one atmosphere will evidently be represented by a number
obtained by multiplying the percentage by the proportion of this
pressure to normal pressure, both expressed for greater simplicity
in centimeters of mercury. Thus the pressure of the oxygen of
ordinary air at 30 cm. of pressure will be represented by the
30
number 20.9 x — = 8.2.
76
Applying now this simple calculation, whose formula is
02xP
-, to all the figures listed in our table, we reach the results
76
given in Column 10. We see that at whatever pressure our birds
were placed, their death came when the pressure of the oxygen
was lowered to values varying between 3.0 and 4.3, which are
precisely the values with which air becomes irrespirable at normal
pressure. The table shows that, even at very low pressures, we
find figures (numbers 28, 30, and 33) which indicate the most com-
plete exhaustion and the weakest tension, when we have taken
sufficient precautions, to which we shall refer in a moment.
The differences between the results of the analyses at different
pressures are exactly of the same order as those which separate
the results obtained at the same pressure. This stands out in the
most striking manner in the graph in Figure 18, which expresses
the results in Column 10. Thus at the same pressure of 24 cm.,
Death in Closed Vessels
527
there are deviations as great as those of the whole tracing, as the
little crosses show. These are differences which experiments made
in apparently identical conditions always display.
T3 0>
as
o ^
J3 CO
+j o
'■J3 -£ S1
.2 £ 8
►> "3 ca
CO
Summing up, we arrive at this very simple statement: In con-
fined air, at pressures less than one atmosphere, the death of spar-
528 Experiments
rows occurs when the tension of the oxygen, measured by the
method that has just been specified, is represented by a number
varying between 3 and 4, which we can call k.
If we refer now to line O of Figure 17, we see that each of its
points corresponds to the equation — = k, therefore xy = 76k.
76
Now k having a value which varies from 3 to 4.3, taking 3.6 as an
average, for the point which corresponds to 41 cm. of pressure, for
41 x 6.5
example, the equation will be = 3.6. In other words, it is
76
the equation of a hyperbola having for asymptotes the axis of the
x's and a parallel to the axis of the y's at the zero of pressures, or,
to use an exact expression, of an equilateral hyperbola.
These facts show us under a new aspect the action of the diminu-
tion of pressure upon the organism. They tend to show that it
consists principally of diminishing the exterior tension of the
oxygen, and, consequently, of placing the animal in conditions
similar to those which would be given it by respiration at normal
pressure in a medium containing less oxygen than the air. We
could even state already that no other important element is in-
volved, since at pressures from 20 cm. to 25 cm. we find again in
the table the figures 3.1 or 3.3, which indicate an exhaustion as
great as at normal pressure.
Continuing this reasoning, we can determine the lower limit of
pressure which it will not be possible to pass without killing the
animals (we are still speaking of sparrows) . It will be given by
x x
the formula 20.9 x — = 3 and 20.9 x — = 4.3, since 3 and 4.3 are
76 76
the extreme numbers given us by the experiments reported above.
4.3 cm. x 76
We reach thus the equation x = = 15.6 cm. for the
20.9
highest figure, and for the lowest, x = 10.9 cm.
But it is clear that, to reach such low pressures, we must take
the greatest precautions, and slowly accustom the animal to this
asphyxia of a new kind. A sudden change surprising it with too
great an oxygen consumption would kill it, and that very thing
Death in Closed Vessels 529
happened (numbers 21, 31, and 32 of the table) at pressures of 20
and even 26 centimeters. We must not forget that the birds which
die in containers of confined air die very slowly, grow cold, and
therefore can live a long time with a very slight consumption of
oxygen. Claude Bernard- showed with admirable sagacity the
difference existing between a vigorous and a weakened animal from
this point of view.
It was with the purpose of reaching the lowest possible point,
by going slowly, that the following experiments were made.
Experiment XXXVIII. March 30. House sparrow. Bell-jar of 50
liters.
Entered at 2 o'clock. Current of air maintained by the steam
pump. At 2:04, 51 cm. of pressure; at 2:05, 39 cm.; at 2:06, 33 cm.;
uneasy, panting a little. At 2:07, 25 cm.; falls with its beak forward,
panting, does not get up again. Pressure rises to 28 cm.; the bird does
not stir; pressure falls suddenly to 24 cm. (2:09 o'clock), and the bird
hops about staggering and falls immediately. At 2:11, 22 cm., same
condition; at 2:13, 16 cm.; violent convulsion; pressure restored to 20
cm.; at 2:25, still 20 cm.; pressure lowered again; at 2:27, only 17 cm.;
and at 2:30, only 16.5 cm. At 2:32, the mercury suddenly goes to 8
cm.; convulsions and death. Rectal temperature is 32°.
Experiment XXXIX. Same day, same apparatus.
Entered at 2:40. In one minute brought to 22 cm.; falls on its side
and does not get up. At 2:43, 20 cm.; at 2:45, 17 cm.; at 2:54, 16 cm.;
at 3:15, 15.5 cm. In the intervals, the pressure was lowered two or
three times suddenly to 10 cm., and raised immediately. The bird
remained motionless, bristling, breathing with difficulty. Taken out
at 3:15, is very cold.
Recovers very well after a quarter of an hour and survives. At
4:30, has a normal temperature.
Experiment XL. January 2. House sparrow, vigorous. Barometric
pressure 753 mm.; bell-jar of 4.5 liters.
Decompression begun, with air flowing through chamber, at 2:35.
At 2:55, the pressure under the bell-jar is only 58 cm.; the bird
is calm.
At 3:05, pressure, 48 cm.; at 3:15, 40 cm.; at 3:25, 30 cm.; at 3:35,
23 cm.; the bird is crouched on its tarsi.
At 3:45, pressure, 17 cm.; the bird is lying on its side, , but does not
appear very sick.
From 3:50 to 3:55 the pressure is lowered to 15 cm.; from 3:55 to
4 o'clock, to 14 cm.; from 4 o'clock to 4:05 to 11 cm.; from 4:05 to
4:10, to 10 cm.; the bird is on its side but fairly quiet.
Air is admitted suddenly; the bird gets up on its feet immediately;
its rectal temperature is 28°. It is warmed by the stove, and gets up
on the perch in its cage. But it dies during the night.
Here are sparrows with which we proceeded slowly enough to
bring on weakness and chill, and which underwent diminutions of
530 Experiments
pressure quite comparable to those which the preceding calcula-
tions indicated. It is a matter of care and patience.
If now we examine Column 11 of Table I, we find numbers
representing the result of the addition of the carbonic acid pro-
duced and the oxygen remaining at the moment of death. They
are represented by the line C02 + 02 in Figure 17. We see that
these different numbers vary between 17.8 and 20.5: the general
average is 18.9. And so we find at all diminutions of pressure the
fact observed by earlier authors, which caused them to make such
strange hypotheses on the nature of asphyxia in closed vessels, that
is, the diminution of the elasticity of the air, or, in other words,
the disappearance of a certain quantity of oxygen which is not
recovered in the carbonic acid given off. Furthermore, — and this
is very evident on the graph — this amount keeps increasing when
the pressure diminishes; above one half atmosphere, it is on the
average 18.7, and below, it is 19.2. So, at very low pressures, there
is given off a greater proportion of carbonic acid in comparison to
that of the oxygen absorbed. In studying the gases of the blood
under diminished pressure, we shall easily understand this
phenomenon.
That is not all: a careful inspection of Column 11 shows us
another interesting fact. If we group on one side all the cases in
which the number indicated in Column 10 is between 3 and 3.5, and
on the other all those in which this number is above 3.5, we shall
find that for the first series the average is 18.6, while for the second
it rises to 19.5. That means that the greater the exhaustion of
oxygen, the greater has been the quantity of this gas not recovered
in the carbonic acid exhaled. Hence we can draw the conclusion
that in asphyxia in closed vessels, whatever the pressure may be,
towards the end of the animal's life, the oxygen, which it continues
to absorb in very small quantities, remains in the tissues under
some form or other, without giving rise to carbonic acid.
This conclusion is corroborated also by the examination of
Column 12 of the table, containing for each experiment the ratio
between the carbonic acid produced and the oxygen consumed.
We see that these numbers are in a general way proportionately
smaller as the pressures become lower. In the first eleven experi-
ments (above a half-atmosphere) the average is 0.85, and for the
others only 0.80. We conclude then that at very low pressures the
proportion of oxygen that is absorbed without producing carbonic
acid is greater than at more moderate pressures.
I tried to ascertain whether some relation existed between the
Death in Closed Vessels
531
numbers contained in Columns 5, 7, and 10, which express different
important elements of our experiments. To grasp these relation-
ships, I drew three graphs in which the experiments are arranged
Fig. 19 — Relations between oxygen tension (graph A), duration of life (B)
and actual capacity of the vessels (C) in death in closed vessels
under decreased pressure.
532 Experiments
according to their numbers in Column 1 of Table I on the axis of
the abscissae, so that pressures decrease from left to right. To
each of these experiments correspond three values plotted on the
vertical ordinate; the first, A, expresses the final tension of the
confined air (Column 10) ; the second, B, the duration of life
(Column 7) : this duration is calculated by reducing the volume
of the rarefied air to 76 cm. and seeing how long the birds lived
for each liter of air: the third, C, represents the volume of rarefied
air reduced to the pressure of 76 cm. of mercury and permits us
to compare the true quantities of air that the birds had at their
disposal.
We do not see very clear relations between the line A which
expresses the oxygen tension at the end of the experiment and line
B which expresses the duration of the lives of the birds. We con-
clude from comparing the two graphs that the greater or less
exhaustion of air (A) is by no means in constant relation to the
length of life (B), since a very short duration may coincide with
considerable exhaustion (Experiment 8) or inversely (Experiment
15). However, if we take the average of the duration of life cor-
responding to very low oxygen tensions (below 3.5, Column 10) ,
we have the figure of 1 hour and 11 minutes; whereas in making
the same calculations for higher oxygen tensions we find 1 hour
and 23 minutes (the general average being, Column 7, 1 hour 16
minutes). And so in a general way, the longer the animal lives,
the more it exhausts the air, very naturally.
Inquiring next into the duration of life in its relation to the
capacity of the bell-jars in which the animals died, and setting
aside the wholly exceptional cases like those of Experiments 16,
21, 31, 32, and even 35 and 36, we see that at first glance graph C,
which expresses these varied volumes, has nothing in common
with graph B. A very considerable capacity may coincide with
a moderate duration of life (Experiments 13 and 24) or inversely
(Experiment 9) . But if, as in the preceding case, we consider
capacities corresponding to longer than average durations of life
(1 hour 16 minutes), we find that their average volume is 2 liters,
while for the more rapid deaths the volume is only 1.5 liters.
Generally speaking, then, life is longer when the capacity of the
vessels is greater (the whole evidently related to the unit of
volume and the unit of pressure).
Thus we confirm, unmodified by the influence of the diminution
of pressure, a law which was earlier formulated by M. Claude
Bernard, who, however, mentions numerous exceptions; the prin-
Death in Closed Vessels 533
cipal ones are due to the calmness or the agitation of the animal
enclosed, which uses up more or less quickly the quantity of air
left at its disposal.
We now have to compare graphs A and C, that is, the capacity of
the vessels with the exhaustion of oxygen. Here again the curves
have little agreement. We even find strongly opposed results, as
in that of Experiment 19, in which maximum exhaustion corre-
sponds to a small vessel, and that of Experiment 24, where in a
very large vessel there was little exhaustion compared to Experi-
ments 14 and 16, which give opposite results. But if we take an
average, we see that numbers less than 3.5 (graph A) correspond
to an average of 1.8 liters, while those that are greater correspond
to 1.6 liters. There is then some advantage in vessels of large
capacity, another conclusion agreeing with those of Claude Bernard.
But the differences are very slight, and when we examine these
numerous results, we can understand the apparent contradictions
of investigators.
Therefore, whatever point of view we take, we find that the re-
sults of the experiments under diminished pressure agree with all
that we know about asphyxia in closed vessels. We are then
more and more led to see in the rarefaction of the air only a physical
process which leads to the same end as the impoverishment of
oxygen, a chemical process. The following data also corroborate
this view.
We know that at very low temperatures and under normal
pressure animals exhaust much less the oxygen of the air in
which they are confined than they do at an average temperature.
Is the same thing true for death in closed vessels at low pressure7
The following experiments give the answer to this question.
Experiments XLI to XLIII, simultaneous. December 12. Pressure
77 cm. The temperature of the laboratory is +6°. After the sparrows
had been placed under the bell-jars, the latter were packed in snow,
and the temperature dropped to about + 2°.
XLI. Bell-jar of 2.25 liters.
Entered at 2:40. Pressure brought to 54 cm., and the cold lowers
it to 52 cm. The bird is found dead at 4 o'clock.
Lethal air: O 8.3; CO,' 11.4.
CO.
CO. + 0* - 19.7; = 0.90.
O.
XLII. Bell- jar of 3.2 liters.
Entered at 2:50. Pressure brought to 44 cm. by vacuum and cold.
At 4 o'clock is breathing with great difficulty; at 4: 15, dead. Lived 1
534 Experiments
hour 20 minutes in a quantity of air corresponding to 2 liters, at
normal pressure, that is, 40 minutes per liter. At 4:35, rectal tempera-
ture 18°.
Lethal air: O. 7.6; CO. 12.0.
CO.
CO. +C = 19.6; = 0.90.
O.
XLIII. Bell- jar of 5 liters.
Entered at 3 o'clock. Pressure brought to 27.5 cm. Living at 5:35.
Found dead at 5:05.
Lethal air: O. 10.4; CO. 8.8.
CO.
CO. + Os = 19.2; = 0.83.
O.
Experiment XLIV. December 13. Outside temperature -\-6°. Pres-
sure 77 cm.
Sparrow placed under bell-jar of 3.2 liters, at 2:45. Pressure
brought to 30.5 cm. including the following action of the cold. The bell-
jar is surrounded by a mixture of ice and salt.
At 3:35, still living; at 3:45, dead. Lived about 55 minutes in an
equivalent of 1.28 liters of air, that is, 43 minutes per liter.
The temperature of the bell-jar is then — 5°. Rectal temperature
of the bird + 16°.
Lethal air: O. 11; CO. 8.8.
CO.
CO. + 0. 3= 19.8; = 0.89.
O.
Experiments XLV to XLVI, simultaneous. December 14. Temper-
ature + 6°. Pressure 76.5 cm. House sparrows.
XLV. Bell-jar of 3.2 liters.
Placed under bell-jar at 12:50, total reduction of pressure 29.5 cm.
The bell-jar is surrounded with ice and salt. The interior ther-
mometer registers + 1° at 1 o'clock; at 1:20, it is — 2°; at 1:35, — 4°;
at 2:05, —4°.
At 2:05, the bird is still alive; dead at 2:10. Lived 1 hour 20 min-
utes in the equivalent of 1.24 liters of air, that is, 1 hour 4 minutes
per liter. At 2: 17, rectal temperature 15°.
Lethal air: O. 10.3; CO. 7.4.
CO.
CO. + O. = 17.7; = 0.70.
O.
XLVI. Bell-jar of 3.2 liters.
Entered at 2:42. Pressure brought to 29.5 cm. No cooling mixture.
The interior temperature of the bell-jar at 3:05 is +8.5°, and at the
time of death, +6.5°. At 4:15, very sick; at 4:25, dead. Lived 1 hour
Death in Closed Vessels
535
40 minutes in the equivalent of 1.24 liters of air; that is, 1 hour 20
minutes per liter. At 4:30, rectal temperature is 19°.
Lethal air: CX 9.2; CO 9.2.
CO
CO + O = 18.4; = 0.79.
O
Table II
1
■i
3
4
5
6
7 8
9
v f
"a!
<D
* w
m ft°
Composition of
c
3
O o
C
o
° O Oto
lethal air
PL,
<u
a
S
4)
H
3i
Is
ft.
« is
Ed
5 V 0) 3
O, CO,
0 1
XLI
+2°
52
2.25
| 8.3 | 11.4 | 5.9
XLII
+2°
44
3.2
1 h. 20m.
40m.
7.6 | 12.0 | 4.4
XLIV
-5°
30.5
3.2
55m.
43m.
11.0 | 8.8 | 4.4
XLV
—4°
29.5
3.2
1 h. 20m.
1 h. 20m.
10.3 | 7.4 | 3.8
XLVI
+6.5°
+2°
29.5
3.2
1 h. 40m.
1 h. 20m.
9.2 | 9.2
3.5
XLIII
27.5
5.0
10.4 1 8.8
3.7
average
57 m.
avg.
4.3
1
Table II, which summarizes these results, shows clearly that
at low temperatures the exhaustion of air really is less complete.
One needs only to compare the figures with the corresponding ones
for the same pressures in Table I. The averages themselves are
enlightening enough; the oxygen tension rose from 3.5 to 4.3.
Moreover, the average duration of life dropped from 1 hour 16
minutes to 57 minutes.
In this double comparison we see that the parallel I made still
continues exactly. We can find many other agreements when we
examine the general phenomena displayed by the animals: changes
in respiration, circulation and temperature; presence or absence
of convulsions, etc. I prefer to devote a special chapter to this
subject.
For the moment we must take another step and pass from the
realm of inductions to that of decisive experiments. The problem
appears in the following terms.
We have seen that, in a confined atmospheric medium, at any
pressure (below one atmosphere), the sparrows die when the
tension of the oxygen in the surrounding air is lowered to an aver-
age of 3.6. When the pressure is sufficiently high, the tension figure
goes thus low only after a certain time, after an exhaustion due to
536 Experiments
the animal's breathing; but the chemical alteration of the air
which is the consequence becomes less and less important, as we
have seen, in proportion as the pressure diminishes; and so, at
about 15 centimeters of pressure, death occurs in pure air: it even
occurs as I have often observed, in an air current, and the con-
finement, the chemical change, are evidently not factors.
If the various disturbances, whose details will be given later,
which begin to appear when the pressure is lowered to 30 centi-
meters; if the serious symptoms, which occur at about 25 centi-
meters; if death, which ensues at about 18 centimeters, are all really
due to the weak oxygen tension at these various periods, we should
be able to avert them by increasing this tension suitably, without,
however, changing the barometric pressure.
Super-oxygenated air: very low pressures. This is easily se-
cured by using artificial air sufficiently rich in oxygen. If, in the
02 x P
expression which represents the oxygen tension, the per-
76
centage of O, increases in the same proportion as pressure P de-
creases, the amount of the tension will remain constant; if this
amount is sufficient, it should produce no disturbance in the ex-
perimental animal. For example, if we pass to a half-atmosphere,
to keep the oxygen tension in ordinary air at normal pressure, we
must double the amount 20.9 and use an artificial air containing
41.8 per cent oxygen.
I shall give details of this important point in another part of
this work. But here, where we are considering nothing but death
in closed vessels, under different low pressures, the result should
be expressed in another way. If our hypothesis is true, we shall
arrive at the following formula: Whatever the pressure employed,
whatever the composition of the artificial air, the death of the
sparrows will always occur when the final tension of the oxygen
falls to about the average amount previously established, that is,
3.6.
The experimental procedure was as follows: After the bird
had been placed under one of the bell- jars of the apparatus repre-
sented in Figure 15, I lowered the pressure in the bell-jar 30 to 40
cm., which seems to have no immediate harmful effect on the birds,
as we saw above. Moreover, I immediately connected cock M with
a gasometer filled with oxygen, and allowed this gas to enter so as
to restore normal pressure. Then I began again to lower the
pressure of this mixture already more oxygenated than ordinary
Death in Closed Vessels 537
air, and again filled up with oxygen. After three or four such
manipulations, the bell-jar was full of a mixture sufficiently oxy-
genated for the purposes of the experiment, that is, causing the
bird to die under the diminution of pressure deemed desirable.
I then took a certain quantity of the mixture for analysis.
I shall now give the details of the experiments; I shall discuss
here only those made at very low pressures. We shall see, in the
chapter dealing with death from carbonic acid, that this element
complicates the question for normal pressure and for moderate
decompressions when super-oxygenated air is used. I shall elimi-
nate it here; besides, the proof we seek will be all the clearer, the
lower the pressures fall.
Experiment XLVII. January 29. Bell- jar of 1.9 liters.
Mountain sparrow. Pressure lowered 50 cm., sick, oxygen admit-
ted; lowered 60 cm., hardly affected, oxygen admitted; lowered 66.5
cm., quite sick, oxygen admitted to 40 cm., pressure lowered 52 cm.
Cocks closed at 3:15; after sample of air is taken, the decompres-
sion is 54 cm., at 3:45, in good condition; at 5 o'clock, panting; the
actual pressure is 19 cm. Dies at 6:30, without a motion.
Actual pressure, 18 cm. Original mixture, O-' 85.9.
Lethal air: CO, 68.1; O2 15.4.
18
CO; tension = 68.1 x = 15.2.
76
18
Oxygen tension = 15.4 x = 3.6.
76
Experiment XLVIII. April 23. Bell-jar of 1.5 liters.
Pressure lowered successively 54 cm., 57 cm., 62 cm., 67 cm.; each
time oxygen admitted, then air admitted until the decompression
equalled 61.5 cm. Cocks closed at 4:12. Found dead at 6:15. Thin layer
of bloody suffusion in the cranial diploe. Pressure is 14 cm.
Lethal air: CO* 48.0; O2 23.8.
CO2 tension = 8.8. Oxygen tension = 4.3.
Experiment XLIX. February 6. Bell-jar of 1.9 liters.
Pressure lowered 30 cm., 50 cm., 50 cm., with successive admis-
sions of oxygen; then to 14 cm. Entered at 2:20; very restless; dead at
4:45. Bloody suffusion.
Actual pressure 12.5 cm. Original mixture O2 88.4.
Lethal air: CO* 66.0; O2 22.2.
CO2 tension = 10.8. Oxygen tension = 3.6.
Experiment L. January 29. Bell-jar of 2.30 liters.
Pressure lowered 48 cm., 52 cm., 64.5 cm., following successive ad-
missions of oxygen; cocks closed at 2:40.
At 2:50, sample of air taken, which lowered the actual pressure
to 10 cm. At 3:30, still moving; at 4:45, dead.
538
Experiments
Actual pressure 8 cm. Original mixture: O 82.3.
Lethal air: CO 37.2; O 41.8.
COs tension = 3.9. Oxygen tension = 4.4.
Experiment LI. February 1. Bell-jar of 1.55 liters.
Pressure lowered 44 cm., uneasy, oxygen admitted; lowered 52
cm., same effect; lowered 65 cm., struggled and vomited; same pro-
cedure again. Lowered 65 cm., then sample of air taken, which lowers
the pressure 68.7 cm., and the actual pressure to 6.6 cm. The bird
moves at every stroke of the pump; very sick at once, and dies in an
hour at the most. Cranial suffusion.
Original mixture: On 87.0.
Lethal air: CO? 17.3; O2 66.7.
CO-- tension = 1.5. Oxygen tension = 5.8.
The results of these different experiments are summarized in
the following table.
Table III
l
2
3
4
5 6
7
0
£
G
+j m
>>
— 0
Composition of
X
O u
0
81
Om
lethal air
O
O <u
nsion
letha
x P
76
X 3
<°£
X'S
<U X
<" r--?
Wfl
Wo,
Oo
HO
o2 co2
H.SO 1
XLVII
18.0
85.9
20.3
15.4 1 68.1
3.6
XLVIII
14.0
23.8 | 48.0
4.3
XLIX
| 12.5
88.4
14.5
22.2 | 66.0
| 3.6
L
8.0
82.3
8.6
41.8 | 37.2
4.4
LI
6.6
87.0
7.5
66.7 1 17.3
5.8
A glance at Column 7 shows that my expectations were realized;
the numbers given are not far from the average previously found.
The last, however, is noticeably higher. But an easy explanation
of this difference is found in the number given in Column 4. In
the very beginning, the bird was placed in an air which was cer-
tainly very rich in oxygen, but in which the actual tension of this
gas was nevertheless extremely low. It was really "exhausted"
air, and the bird was in asphyxiating conditions at the beginning
of the experiment; and so it was in great distress immediately.
The verification of the hypothesis which had guided us comes
likewise, and perhaps with still more evidence, from the considera-
tion of the pressures to which it was possible to bring the birds
without killing them immediately. While with ordinary air I
could hardly go below 16 cm., we find here, in Column 2, pressures
of 14, 12, 8, and even 6.6 centimeters. And what makes this fact
Death in Closed Vessels 539
still more remarkable is that I could not use the precautions the
importance of which I stressed above, and that the decompression
was therefore always very sudden.
Applying to oxygen the reasoning used on page 528 and fixing
as limits of minimum tension of oxygen compatible with life the
numbers 3 and 4.2, we find for the lowest barometric pressures to
which it would be possible theoretically, in pure oxygen, with all
necessary slowness and precautions, to bring sparrows without
x
killing them the numbers taken from the equations 100 x — = 3
76
x
and 100 x — = 4.2. Whence x = 2.3 cm. and x = 3.2 cm. It is
76
evident that in practice one cannot go so low.
The ultimate phenomenon, that is, death, is not the only one
whose barometric limit varies with the oxygen percentage of the
medium. The other disturbances, uneasiness, cessation of move-
ments, vomiting, general weakness, are in the same category. It
has always been easy to prove that the bird which seemed sick at
first diminution of pressure, when it reached 40 cm. for example,
gave no sign of uneasiness when, after admitting oxygen, I de-
creased the pressure again and reached the same level. I had to
go farther, to 50 cm. for example, to get the same morbid
phenomena.
The experiments with super-oxygenated air have therefore com-
pletely proved what the experiments with ordinary air showed to
be certain. It would have been possible to get a counter-verifica-
tion from experiments in which we would have used air poor in
oxygen. I could give with details some data of this sort; but the
proof must already be thoroughly convincing in the reader's mind,
and I shall merely say that with air containing only 10.2 per cent
of oxygen, I could not reach a pressure lower than 28 cm., the
oxygen tension then being 3.7.
It is then established that either in a closed vessel by respiratory
depletion, or in a current of air, death occurs in rarefied air in
consequence of a lessening of the tension of the ambient oxygen.
Diminution of barometric pressure is only one method of obtaining
this insufficient tension. But there is a second method which con-
sists of lowering the percentage of oxygen; we need only consider
02 x P
the equation mentioned s -> often already = 3.6.
76
540 Experiments
The general conclusion from all this is that all disturbances,
symptoms, and death, which occur in consequence of diminution
of pressure, are due entirely to asphyxia; an animal subjected to an
increasing diminution of pressure is like an animal which smothers
in closed vessels in ordinary air, with the unimportant reservation,
as we shall see later, of the action of the carbonic acid produced.
When an animal in a closed vessel is subjected rapidly to a certain
decompression, and allowed to die, as in the preceding experiments,
the gradual depletion of the oxygen of the air in which it is con-
fined acts exactly as if one continued in a pure air to diminish the
barometric pressure around it.
Oxygen tension is everything; barometric pressure in itself does
nothing or almost nothing.
I shall stress these facts and the conclusions to be drawn from
them in another chapter, and I shall also indicate elsewhere the
practical results which may be deduced from them.
I shall not now dwell upon the exterior phenomena displayed
by the sparrows subjected to the lowering of pressure. This study,
generalized and supported by precise observations made on animals
of different species, will be taken up in a special chapter. I shall
merely mention today three principal facts: 1, the increase in
number of respirations; 2, the drop in temperature; 3, the convul-
sions which precede death, and which will give us an opportunity
to judge the theory which attributes the convulsions to the action
of excess carbonic acid in the blood.
I shall now give the results of experiments made on birds other
than sparrows.
Experiments LII to LV, simultaneous. July 2. Temperature 20°;
pressure 76 cm. Owls (Stria; psilodactyla, Lin.)
LII. Young, weighing 125 grams. Bell-jar of 2.25 liters.
Entered at 3:07; left at normal pressure.
Seemed affected at about 3:50, dies at 5 o'clock, with 3.8 cm. dim-
inution of pressure due to absorption. Dead after 1 hour 20 minutes
of distress. After 15 minutes, the rectal temperature is 31.3°; no
rigidity.
Lethal air: O 3.3; CO 13.4.
CO.
CO. + O. = 16.7; 0.76.
O;
LIII. Like the foregoing. Bell-jar of 7 liters.
Began at 3:15. At 3:20, pressure has been lowered 22 cm., some-
what uneasy. At 3:22, pressure has been lowered 41 cm., the bird is
calm; at 3:25, staggers; cocks closed. Actual pressure 27.7 cm.
Death in Closed Vessels 541
Soon closes its eyes and seems to sleep. Dies at 4:30, after 1 hour
of uneasiness. Ten minutes after death, rectal temperature is 35.0°;
after 25 minutes, it is 33.8°: no rigidity.
Lethal air: O 13.4; CO 6.4.
CO,
CO + O = 19.8; = 0.87.
O
Oxygen tension = 4.8.
LIV. Similar. Bell-jar of 7.5 liters.
Began at 3:18; at 3:20, decompression of 33 cm., no uneasiness; at
3:27, 51 cm. of decompression, vomits; at 3:28, actual pressure 22 cm.
Cock closed.
At 3:32, falls and seems about to die; a little air admitted and the
pressure rises to 32 cm.; the bird gets up. Same procedure repeated
twice. At 3:58, pressure is 23.5 cm., the bird has half risen; cocks
closed.
At 4:10, pressure lowered to 22.5 cm. Dead at 4:35, without con-
vulsions, after about 1 hour 10 minutes of respiratory embarrassment.
After 20 minutes, the rectal temperature is 30.2°; after 30 minutes,
29.7°: no rigidity.
Lethal air: O 17.1; CO 3.3.
CO.
CO. + O = 20.4; .= 0.87. Oxygen tension = 5.0.
O2
LV. Owl five years old, weighing 170 grams. Bell-jar of 11.5
liters.
Began at 3:08; considerable agitation, which lasts until 3:13, when
the pressure has been lowered 36 cm., the bird then grows calm. At
3:16, pressure has been lowered 44 cm., vomits twice. At 3:21, 48
cm., at 3:26, 57 cm., that is, approximately 19 cm. of actual pressure.
Falls and is about to die; pressure raised to 28 cm., the bird gets up
after a few minutes. Same procedure repeated twice, but each time
the bird is evidently less affected. At 4:03, pressure is 20.2 cm.: bird
falls; cocks closed.
At 4:10, lowered to 19 cm., bird is still prostrate, beak forward.
Dead at 4:45, without convulsions, after about 1 hour 20 minutes of
respiratory embarrassment. Twenty-two minutes after death, rectal
temperature 30.2°; after 30 minutes, 29.6°: no rigidity.
Lethal air: O 17.6; CO. 2.6.
CO
CO= + 0 = 20.2: =0.79. Oxygen tension = 4.4.
' O2
We see that our rule is verified, in spite of an irregularity
greater than usual, presented by the experiments made at normal
pressure. The value of the oxygen tension in the lethal air was,
in fact: at 76 cm., 3.3; at 27.7 cm., 4.8; at 22.5 cm., 5; at 19 cm., 4.4.
542 Experiments
These last barometric pressures are very low, and quite evidently
the transitions had not been careful enough.
Experiment LVI. August 3, hawk (Falco tinnunculus, Lin.). Pres-
sure 75.5 cm. Bell-jar of 13.5 liters.
Began at 3:25; current of air. The decompression at 3:30 is 8
cm.; at 3:35, 16 cm.; at 3:45, 30 cm.; at 3:50, 40 cm.; at 3:53, 50 cm.;
that is, actual pressure about 25.5 cm. Bird vomits and falls; pressure
raised to 31.5 cm., then slowly lowered to 25.5 cm.; the bird, which
had recovered a little, falls again, seems about to die, and the pres-
sure has to be raised to 27.5 cm.
At 4:05, pressure is 25 cm.; at 4:10, 24.5 cm.; at 4:15, 21.5 cm.;
the bird vomits, staggers, and reels, but seems to recover a little, while
remaining weak. At 4: 17, the pressure is only 20 cm.; at 4:20, 19.5 cm.
Cocks are closed, and the bird dies at 4:32. Lived about 40 minutes
with respiratory embarrassment. Eight minutes after death, rectal
temperature was 37.4°.
The air, as one might expect, is hardly altered; C^ 20.0; CO 0.8.
Oxygen tension = 5.1.
The interesting point of this last experiment is that a bird of
prey, zoological neighbor of the vultures and the condors which
mount to prodigious heights, was at least as sensitive to the lower-
ing of pressure as a simple sparrow.
B. Experiments on Mammals.
These have been rather few, since the principal point of the
question had been settled by the experiments on sparrows. They
have shown me, as a general fact, that mammals can be brought
to pressures considerably lower than birds. One might have con-
jectured as much anyway, since mammals deplete the oxygen of
the confined air more than birds do. (See my Lessons on the
Physiology of Respiration, page 510.)
They are, besides, more pliable, so to speak, that is, easier to
reduce to the state of cold-blooded animals, enduring then as the
latter do, extremely low pressures (See later) ; this is especially
true of rodents. A remarkable example of this fact (Exp. LVII)
was shown by a guinea pig, which, having been placed for four
hours in a current of air (temperature 15°) , continued to live under
a pressure constantly lower than 20 cm., which was repeatedly
lowered to 11 cm. for four or five minutes. It is true that after this
time the unfortunate animal remained motionless, almost uncon-
scious, with a rectal temperature of 20°, and that it died several
hours after the experiment.
In another case (Exp. LVIII) , a guinea pig was brought to and
maintained at a pressure of 12 cm. for about a quarter of an hour,
Death in Closed Vessels 543
by a gradual lowering of the pressure lasting an hour and a half
The animal was then very weak, and its rectal temperature was
only 25°; but three minutes after the animal was restored to nor-
mal pressure, the temperature rose to 31°, and the guinea pig could
already get up on its feet. This animal survived.
CATS. Experiments LIX to LXIII, simultaneous. July 11; pres-
sure 75 cm. Cats from a month to a month and a half old.
LIX. Cat weighing 280 grams. Bell- jar of 3.2 liters. Entered at
3:15; normal pressure; died at 4:35, without convulsions.
280 grams lived 1 hour 20 minutes in 2.920 liters of air, which
gives per liter and per kilogram
80 m. 280
x = 7.7 m.
2.92 1000
Lethal air: O* 4.4; CO-' 13.4.
CO
CO^ + O-" = 17.8; = 0.81. Oxygen tension = 4.4.
LX. Weight 380 grams. Bell-jar of 7 liters.
Began at 3:20; at 3:25, the pressure is 51.2 cm.; cocks closed; died
at 4:45.
380 grams lived 1 hour 20 minutes in 6.62 liters of air at a pres-
sure of 51.2 cm.; reducing to 76 cm. of pressure and to 1000 grams,
we get the value.
80 m. 380 80 m x 380 x 76
x = = 7.1 m.
6.62 x 51.2 1000 6.62 x 51.2 x 1000
76
Lethal air: O? 7.2; CO^ 11.4.
COs
CO- + 0? = 18.6; = 0.81. Oxygen tension = 4.9.
O
LXI. Weight 460 grams. Bell-jar of 13.5 liters.
Began at 3:25; at 3:44, pressure is 21.8 cm. The animal is very
sick, 250 respirations per minute. At 4 o'clock, violent convulsive
movements, falls back, and dies at 4: 13.
460 grams lived 29 minutes in 13.04 liters of air at 21.8 cm., which
gives 3 minutes per liter at 76 cm. and per 1000 grams.
Lethal air: O* 15.5; CO* 5.1.
CO2
CO2 + 02 = 20.6; = 0.94. Oxygen tension = 4.4.
O2
544 Experiments
LXII. Weight 665 grams. Bell-jar of 15.5 liters.
Began at 3:22; at 3:40, the pressure is 27 cm.; vomits, defecates.
At 3:48, pressure is only 16 cm.; very uneasy. Cocks closed. Dies
at 3:53, without convulsions.
Duration of life, per kilogram and per liter, 1 minute.
Lethal air: O* 19.0; CO* 1.0. O* x P = 4.
LXIII. Weight 485 grams. Bell-jar of 15.5 liters.
Pressure reduced in 15 minutes to 16 cm. Lying down, panting;
dies in 20 minutes.
Duration of life, per kilogram and per liter, 3 minutes.
Experiment LXIV. August 4. Cat weighing 2.57 kilos; bell-jar
of 21.5 liters.
Began at 4:10. At 4:22, the actual pressure is 29.5 cm. Cocks
closed; the animal does not seem in much pain.
At 4:37, violent struggles and cries. At 4:45, convulsions, with
quivering of the cutaneous muscles. Dead at 4:47.
Duration of life, per kilo and per liter, 8.7 minutes.
Lethal air: O* 10.3; CO 9.6.
CO*
CO* + O* = 19.9; =0.90. Oxygen tension = 4.
O*
The value of the oxygen tension in these experiments was: at
76 cm., 4.4; at 51.2 cm., 4.9; at 29.5 cm., 4; at 21.8 cm., 4.4; at 16 cm., 4.
If now we find the duration of life taking as base a liter of air
and reducing the calculation to one kilogram of body weight, the
result is: at 76 cm., the duration of life was 7.7 minutes; at 5.12 cm.,
7.1 minutes; at 29.5 cm., 8.7 minutes; at 27 cm., 3 minutes; at 16 cm.,
3 minutes. We must not forget that the cat at 29.5 cm. was very
different from the others, and being much bigger, should consume
less oxygen in a given time, and consequently live longer in a
given space.
I thought it would be interesting to experiment on new-born
animals, which resist asphyxia much longer than adults, as is
known. However, I could not go noticeably farther with them in
decompression than with adults. Kittens born two days before,
brought rapidly to 8 to 12 centimeters of pressure, died in seven
or eight minutes.
Here are the results of experiments in which the air was
analyzed.
Experiments LXV to LXVIII, simultaneous. July 4; pressure 76 cm.
Kittens born July 1, weighing an average of 125 grams.
LXV. Bell-jar of 675 cc, subtracting displacement of animal, 550 cc.
Entered at 2:42; brought rapidly to a pressure of 58 cm. At 3:40
seems dead, but does not really die until 4:35.
Lethal air: O* 3.0; CO* 17.1.
Death in Closed Vessels 545
CO*
CO -j- O2 = 20.1; = 0.95. Oxygen tension = 2.2.
O2
LXVI. Bell- jar of 2.5 liters.
Entered at 3 o'clock; at 3:06, pressure is 25.5 cm.; cocks closed;
dies at 5:40.
Lethal air: O* 7.1; CO2 13.5.
CO2
CO + 02 = 20.6; = 0.98. Oxygen tension = 2.4.
O2
LXVII. Bell-jar of 3.2 liters.
Entered at 2:54. At 3 o'clock, pressure 20.5 cm.; mews. Cocks
closed. Dies at 7:15.
Lethal air: Oa 8.5; CO* 12.0.
CO2
CO* + 0* = 20.5; = 0.97. Oxygen tension = 2.2.
O2
LXVIII. Bell- jar of 5 liters.
Entered at 2:38; at 2:48, pressure is 22 cm.; cat still walks and
mews; at 2:53, pressure is 16.2 cm.; animal is lying flat. Cocks closed.
At 3:08, pressure lowered to 13.4 cm.
Dead at 7:35.
Lethal air: O* 13; CO2 7.
CO2
CO^ + O- = 20.0; = 0.98. Oxygen tension = 2.2.
O2
O, x P
The ratio is maintained here with remarkable regu-
76
larity at 2.2, a number about half that given by adult cats.
Already, in my Lessons (page 510), I had found that, while
adult cats leave on the average 5.3 per cent of oxygen in confined
air, when they die at normal pressure, new-born kittens left only
3.0 per cent. For adult rats, the average was 2.0 per cent, and for
a new-born rat, 0.75 per cent.
If now we make the calculations necessary to find the duration
of life of these new-born kittens, reduced to a liter of air at 76 cm.
and to a kilogram of body weight, as we did for the adults, we find
that this duration is: at 58 cm., 33 minutes; at 25.5 cm., 24 minutes;
at 20.5 cm., 37 minutes; at 13.4 cm., 32 minutes.
We see that the duration of life was obviously the same at very
low pressures as at average pressures. Moreover, comparing these
figures with those obtained from the study of adult cats, we see
546 Experiments
that the duration of life of the new-born kittens was about four
times greater. These two facts agree with what is known about
the vital resistance of new-born animals.
Finally, it is interesting to note that the ratio between the
oxygen consumed and the carbonic acid produced was considerably
higher in the new-born than in the adults: its average, in fact, is
0.97, while for adults it is only 0.86.
DOGS. Experiment LXIX. March 11. Dog weighing 4.3 kilos.
Bell- jar of 31 liters.
Entered at 1:40 at a pressure of 43 cm. Uneasy; lies down at 2
o'clock; found dead at 2:20.
Air at 2 o'clock: O2 5.5; CO2 16.1.
Air after death, O 5.4; CO 16.7. Oxygen tension = 3.0.
RABBITS. Experiment LXX. March 15. Rabbit. Bell-jar of 11.5
liters.
Entered at 2:28. Left at normal pressure.
At 3:50, standing, panting; at 3:55, struggles; at 4 o'clock, falls;
at 4:30, last breath, without convulsions. Fifteen minutes after, its
rectal temperature is 34°.
Lethal air: O2 3.7; CO2 15.2.
CO2
C02 + ©2=18.9; = 0.96. Oxygen tension = 3.7.
O2
Experiment LXXI. March 16. Rabbit weighing 1.900 kilos. Bell-
jar of 20.75 liters.
Began at 2:05; at 2:25, the pressure is only 41 cm. Cocks closed.
At 2:55, uneasiness; at 3:20, great uneasiness; at 3:35, falls; at 3:50,
dead without convulsions; 5 minutes after, the rectal temperature is
35.3°.
Lived 1 hour 25 minutes in 18.85 liters of air at 41 cm., which
gives, per liter and per kilogram, a duration of 16 minutes.
Lethal air: O2 5.9; CO2 13.3.
CO*
CO2 + O2 = 19.2; = 0.81. Oxygen tension = 3.2.
O2
Experiment LXXII. March 14. Pressure 76.6 cm.; temperature
13°. Rabbit weighing 1.340 kilos. Bell-jar of 31 liters.
At 2:27, began the current of air; the manometer rises slowly;
at 2:58 pressure lowered 41 cm.; up to that point the animal remained
perfectly quiet. At 3:02, pressure lowered 50 cm.; rabbit becomes
uneasy; the inlet cock is closed, and pumping continued. At 3:07, the
pressure is only 15.6 cm.; the animal lies down. At 3:12, it is 16 cm.
Dead at 3:20.
Lethal air: O2 19; CO2 1.6.
CO.-
CO2 + O2 = 20.6; = 0.84. Oxygen tension = 4.0.
O2
Death in Closed Vessels 547
Experiment LXXIII. March 15. Rabbit weighing 1.650 kilos.
Bell-jar of 20.75 liters.
Began at 3:48. At 4:05, the pressure is 29 cm. Cocks closed.
The animal dies at 6:42; ten minutes after, its temperature is 32°.
Nothing can be said about its duration of life, because a little air
entered during the experiment.
Lethal air: Oa 11.0; CO, 9.0.
CO,
CO* +0=20; =0.90. Oxygen tension = 4.2.
O,
The value of the ratio O x P in these four experiments is: at
76
normal pressure, 3.7; at 41cm., 3.2; at 29 cm., 4.2; at 16cm., 4.0.
GUINEA PIGS. Experiments LXXIV-LXXV, simultaneous. Aug-
ust 5.
LXX7V. Weight 420 grams. Bell- jar of 3.2 liters. Entered at
3:45, at normal pressure. Dead at 5:05, after uneasiness, sudden leaps,
etc. . . . Never remained quiet. A quarter of an hour later, its rectal
temperature is 37°.
420 grams lived 1 hour 20 minutes in 2.78 liters of air, that is,
12 minutes per liter and per 1000 grams.
Lethal air: O* 2.3; CO, 16.4.
CO,
CO- + Os = 18.7; = 0.88. Oxygen tension = 2.3.
02
LXXV. Weight 470 grams. Bell-jar of 5 liters.
Began at 3:55, and brought in 2 minutes to 46.5 cm. of actual
pressure.
Remains perfectly quiet. At 5:17, convulsive trembling. Dies at
5:20; 17 minutes after, the rectal temperature is 34°.
470 grams lived 1 hour 24 minutes in 4.53 liters at 46.5 cm., repre-
senting at 76 cm., 2.10 liters. Therefore 1000 grams lived 14 minutes
per liter.
Lethal air: O, 3.5; CO, 16.0.
CO,
CO, + O, = 19.5; = 0.92. Oxygen tension = 2.1.
O,
Experiments LXXVI — LXXVII, simultaneous. June 23.
LXXV7. Weight 580 grams. Bell of 13 liters.
Began at 1:45. Reduced to a pressure of 16 cm. with current of
air at 2:45. Dead at 3:10; 27 minutes after, its rectal temperature is
31.5°.
Lived 1 hour 12 minutes in a volume of air corresponding to 2.6
liters at 76 cm., that is, 16 minutes per 1000 grams per liter.
548 Experiments
Lethal air: O. 14.5; CO 9.8.
CO.
CO- + Oa = 24.3; = 1.51. Oxygen tension = 3.0.
O*
LXXVII. Weight 490 grams. Bell- jar of 10 liters.
Began at 1:45. Brought to a pressure of 12 cm. at 2:45.
Dies at 3 o'clock; 17 minutes after, temperature is 33.3°. Lived 15
minutes in 1.5 liters of air at 76 cm.; that is, 4.9 minutes per liter and
per 1000 grams.
Lethal air: O. 14.5; CO? 16.0.
CO.
CO, + 0, = 24.3; =1.51. Oxygen tension = 2.1.
O.
Experiment LXXVIII. Weight 485 grams. Bell-jar of 13.5 liters,
pressure 76 cm.
Began at 3:24; no uneasiness. At 3:30, pressure lowered 50 cm.:
staggers, then recovers; respiratory rate 100, walks a little. At 3:34,
pressure lowered 56 cm.; respiratory rate 135; at 3:35, pressure low-
ered 58.5, lies down on its belly. At 3:40, actual pressure 13.6 cm.;
respiratory rate 80, violent, painful. Cocks closed.
3:45, still lying down, pupils dilated; 3:46, little convulsive shud-
ders; 3:47, fallen on its side; convulsive movements; rigidity; belly
enormously swollen. 3:49, dies, having lived 9 minutes.
After 13 minutes, rectal temperature is 34.6°: after 36 minutes,
31.8°; after 1 hour 16 minutes, 28.4°, and rigidity begins; after 2 hours
11 minutes, 25.4°; slight rigidity.
Lethal air: O. 19.1; CO. 2.3.
CO.
CO. + O. = 21.4; = 1.27. Oxygen tension = 3.4.
O.
Experiments LXXIX-LXXXI, simultaneous. May 28. Pressure 76.3
cm.
LXXIX. Weight 620 grams. Bell-jar of 16 liters.
Began at 2:32; at 2:35, pressure lowered 41.3 cm., that is, 35 cm.
of actual pressure; cocks closed.
At 4:50, falls on its side; at 5:30, dies; 30 minutes after, its rectal
temperature is 28°.
620 grams lived 2 hours 55 minutes in 4.44 liters of air at 76 cm.
Which gives 24 minutes per, 1000 grams and per liter of air at 76 cm.
Lethal air: O. 4.9; CO. 17.2.
CO,
CO. + 0. = 22.1; =1.07. Oxygen tension = 2.2.
O,
LXXX. Weight 520 grams. Bell-jar of 13.5 liters.
Began at 2:37. At 2:44, pressure 27.8 cm.; cocks closed.
At 4:10, fallen on its belly; at 4:55, on its side; dead at 5:05; 15
minutes after, its rectal temperature is 28°.
Death in Closed Vessels 549
520 grams lived 2 hours 20 minutes in 4.76 liters of air at 76 cm.;
which makes 17 minutes, per 1000 grams and per liter of air at 76 cm.
Lethal air: O* 5.4; CO2 15.7.
CO2
CO, _|_ 02 = 21.1 ; =1.01. Oxygen tension = 2.2.
O2
LXXXI. Weight 620 grams. Bell- jar of 19 liters.
Began at 2:40; at 2:49 the pressure is 19.5 cm.; the animal stag-
gers. Cocks closed.
At 2:55, falls; at 3:20, a little better; at 4:15, still making efforts
to rise; at 5:10, convulsive jerks; dies at 5:30; 20 minutes after, the
rectal temperature is 23°.
Lived 2 hours 40 minutes in 4.71 liters of air; which gives 21
minutes, per 1000 grams and per liter at normal pressure.
Lethal air: O* 8.1; CO2 15.6.
CO2
CO + 02 = 23.7; = 1.21. Oxygen tension = 2.0.
O2
The value of the oxygen tension in these different experiments
was:
At normal pressure, 2.3; at 46.5 cm., 2.1; at 41.3 cm., 2.2; at
27.8 cm., 2.0; at 19.5 cm., 2.0; at 16 cm., 3.0; at 13.6 cm., 3.4; at
12 cm., 3.0.
It will be noted that at very low pressures the sum C02 + 02
was: 21.1; 21.4; 22.1; 22.1; 23.7; and 24.3, that is, higher than the
original proportion of oxygen. The excess is due, no doubt, to the
carbonic acid contained in the intestines of these rodents, whose
bellies balloon out at the beginning of very low pressures, and
which probably then let escape a part of their expanded gases.
As to the duration of life, reducing it to 1000 grams of body
weight, it was, per liter, : at normal pressure, 12 minutes; at
46.5 cm., 14 minutes; at 41.3 cm., 24 minutes; at 27.8 cm., 17 minutes;
at 19.5 cm., 21 minutes; at 16 cm., 16 minutes; at 13.6 cm. and at
12 cm., death came much more rapidly. We find here a regularity
not displayed by the birds, which were extremely variable in their
behavior under the bell-jars. The two extremes 12 and 24 are
explained by the incessant movement or the complete calm of the
experimental animals.
If we compare these numbers with those furnished us by the
other mammals, we see that they are about double those given by
adult cats/about equal those of rabbits, and much lower than those
of new-born kittens. Let us say in conclusion that for sparrows,
whose ordinary weight is about 30 grams, making the same calcula-
550
Experiments
Table IV
1
2
3
4
5
6
7
8
9
10
01
■3« |
g
,i,
o £J2
§
<u
uS'JS
a
~ £ u
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o
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Composition
01
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W
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S
o
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U
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o
^2 c-
| s 5 «
of lethal air
5
Mrv
>> | to
81"
6 1
LII
Strix psilo-
gm.
c.
lit.
h.m.
m. | 02
CO,
dactyla
125
76
2.25
1 53
6.2
3.3
13.4
3.3
LIII
Id.
125
27.5
7
1 10
3.4
13.4
6.4
4.8
LIV
Id.
125
22.5
7.5
37
2.1
17.1
3.3
5.0
LV
Id.
170
19
11.5
35
2.1
17.6
2.6
4.4
LVI
Falco Tin-
nunculus
19.5
13.5
12
20
0.8
5.1
av3.4|
1
av.4.5
MAMMALS |
1
LIX
LX
LXIV
LXII
LXI
LXIII
Cat 1 mo.
old
Id.
Adult cat_
| Cat 1 mo.
| old
I Id
Id
280
380
2570
460
665
485
76
51
29.5
21.8
16
16
3.2
7
21.5
13.5
15.5
15.5
LXV
LXVI
LXVII
LXVIII
Cats 3
days old
Id
Id.
Id.
125 I
125 |
125 |
125 |
58
25.5
20.5 |
13.5 |
10.5
2.5
3.2
5
1 20
1 20
25
29
05
20
7.7
7.1
8.7
4.4
7.2
10.3
13.4 I 4.4
11.4 I 4.9
9.6 | 4
3 15.5 5.1
— I 19 I 1
3
av. 5.9
1 55
2 35
4 15
4 30
33
24
37
32
av.31|
4.4
4
av. 4.4
0.3
7.1
8.5
13
17.1
13.5
12
7
| 2.2
| 2.4
| 2.2
| 2.2
| av.2.2
LXIX | Dog
4.3K. | 43 1 31
5.4 I
| 3.0
LXX | Rabbit .
LXXI | Id
LXXIII | Id. _-__.
LXXII | Id. ___.
I
| 11.5
I 20.7
I 20.7
I 31
I
2
1 25
13
16
3.7
5.9
11
19
15.2
13.3
9
1.6
3.7
3.2
4.2
4.0
av.3.8
LXXIV | Guinea pig
LXXX
LXXIX I
LXXX |
LXXXI |
LXXVI |
LXX VIII | Id.
LXX VII | Id.
I
Id.
Id.
Id.
Id.
Id.
420
76
470
46.5
620
35
520
28
620
19.5
580
16
485
13.5
490
12
3.2
5
16
13.5
19
13
13.5
10
20
20
55
20
40
12
9
15
Av.
17.3
2.3
3.5
4.9
5.4
8.1
14.5
19.1
19
16.4
16
17.2
15.7
15.6
9.8
2.3
3.1
2.3
2.1
2.2
2.0
2.0
3.0
| 3.4
| 3.0
| av.2.5
Death in Closed Vessels 551
tions, we should find an average of about two minutes per kilogram
and per liter. Now, if we refer to the celebrated and classic work
of Regnault and Reiset on respiration, we shall find analogous
results, that is, the greater consumption of oxygen in a given time
by carnivores than by herbivores, by birds than by mammals, by
small animals than by large ones, etc.
All the data which have just been given are summarized in
Table IV.
I add, in conclusion, the account of an experiment (Exper.
LXXXII) made on a hedgehog July 6, with the purpose of trying
to put this animal into a state of hibernation by keeping it for a
certain time at very low pressure. But we could not, without
imminent danger, pass below a pressure of 18 cm.; at 26 cm., the
animal uncurled and vomited. After two hours, during which the
pressure varied between 28 cm. and 18 cm., we removed the ani-
mal, which recovered rapidly and survived. This hedgehog there-
fore behaved like a cat or any other animal not endowed with the
remarkable power of hibernation.
C. Experiments on cold-blooded animals.
I made only a few experiments on cold-blooded animals. Frogs,
so useful for other researches, often manifest a strange unevenness
in duration of life, composition of lethal air, etc., when they are
allowed to die in closed vessels, even at normal pressure. However,
here is a series of simultaneous experiments, in which, by taking
great precautions and choosing my subjects with great care, I suc-
ceeded in getting an interesting result:
Experiments LXXXIII-LXXXVII, simultaneous. June 15, at 3
o'clock; temperature 22°.
LXXXIII. Normal pressure, vessel of 275 cc; dies at 5 o'clock
in the evening, June 17.
Lethal air: O 2.7.
LXXXIV. Pressure of 20 cm.; vessel of 1.350 liters, representing
355 cc. at normal pressure; it dies June 16 at 2 o'clock.
Lethal air: O- 8.4. Oxygen tension = 2.2.
LXXXV. Pressure of 14 cm.; vessel of 1.9 liters, representing
350 cc. at normal pressure, dies June 16 at 2:50.
Lethal air: O 15.3. Oxygen tension = 2.8.
LXXXVI. Pressure of 10 cm.; vessel of 2.2 liters, representing
290 cc. at normal pressure; lived 4 hours.
Lethal air: O? 18.5. Oxygen tension = 2.4.
LXXXVII. Pressure of 5.5 cm.; vessel of 2.8 liters, representing
200 cc; lived 2 hours.
Lethal air: Oa 18.6. Oxygen tension = 1.3.
552 Experiments
Finally I report the results of an experiment made on an insect,
the poplar beetle (Chrysomelida) :
Experiment LXXXVIII. August 3, 4 o'clock in the evening;
temperature 24°. 10 grams of beetles entered:
A. In a bell- jar of 60 cc. at normal pressure.
B. In a bell-jar of 800 cc. at a pressure of 9 cm.
C. In a bell-jar of 1.5 liters at a pressure of 4 cm.
On August 4, at noon, the insects are motionless and seem dead;
the air of the bell- jars no longer has a trace of oxygen; there as 18
to 20 per cent of CO--. The insects return to life about an hour after-
wards.
3. Conclusions.
The results which the data given in the present subchapter
have brought us can be summarized in the following conclusion:
In a closed vessel, at pressures below one atmosphere, death
occurs when the tension 0.2 x P of the oxygen of the air is reduced
to a certain value which is constant for each species, or at least
varies within narrow limits around an average (4.4 for adult cats;
3.6 for sparrows; 2.5 for guinea pigs; 2.2 for newborn kittens) .
This average remains the same, whatever the initial composition
of the air used; but for super-oxygenated air the carbonic acid
must be absorbed as it is produced.
Subchapter II
PRESSURES ABOVE ONE ATMOSPHERE
1. Experimental Set-up.
After studying the composition of confined air which had be-
come irrespirable under pressures less than one atmosphere, it
was quite natural to find out what would happen if one used higher
pressures. We have seen that, the weaker the pressure, the greater
is the proportion of oxygen remaining in the lethal air, or, in other
words, the less the air is exhausted. Would this law hold good at
higher pressures? Would there come a moment when a sparrow
would exhaust the oxygen of the air under pressure, as the beetles
of which I gave an account above did at weaker pressures? Apply-
ing the law and taking as an average of the exhaustion in oxygen
at normal pressure the figure 3.6, at 3.6 atmospheres we should find
only 1 per cent of oxygen in the air which had become lethal by
Death in Closed Vessels 553
confinement, at 7.2 atmospheres only 0.5 per cent, and so on. We
shall see how far this hypothesis is from the truth.
In the experiments which I shall report, I used sparrows almost
exclusively. Their small size allowed me to use glass apparatuses
whose advantages are evident, but whose dangers, when highly
compressed air is used, are no less evident. In fact, glass has this
serious disadvantage, that one is never sure that an apparatus
which withstood a certain pressure at a certain moment, will be
able to withstand it again. Furthermore, under the influence of
atmospheric changes, the metallic pieces in which it must be held
expand or contract in lengthy experiments, following a law dif-
ferent from that of the glass, which is thus subjected to pulls in
opposite directions which threaten its solidity and may even crack
it without the application of any pressure, since these glasses are
very thick. At any rate, thanks to the precautions we used, the
accidents which occurred never had serious consequences.
One of the apparatuses which I used most frequently and which
allows me to compress air up to 25 atmospheres, consists of a glass
cylinder, of a capacity of 650 cc. and a thickness of 18 millimeters,
protected by a large-mesh jacket. This reservoir is topped with a
bronze part, which exactly fits its orifice, or rather fits another
fixed bjonze plate which is fastened to the stand on which the
reservoir rests by four steel columns which pass through both the
fixed part and the movable part. These two parts are solidly held
by four movable nuts which screw on the steel columns. All of
this is plainly visible in Figure 20.
A Bourdon manometer, which indicates the pressure of the air
in the reservoir, is fixed on the immovable plate. A screw cock
with a very small opening at the right of the cylinder permits one
to take a sample of this air whenever he wishes. To do so, one fits
to this cock a rubber tube which dips into a mercury basin below
a graduated tube; if then this cock is opened carefully, the com-
pressed air escapes from the apparatus and enters the graduated
tube; I always took care, of course, to let out a certain quantity
before taking what I intended to analyze.
The air is compressed in the reservoir by means of a small force-
pump; I had this pump enclosed in a metal jacket through which
a constant stream of water passes; the operation of it is then less
painful and — which is more important — no hot air is pumped to
the animal. I can thus reach a pressure of 25 atmospheres in about
20 minutes. Finally, a large cock fastened to the movable part
topping the cylinder opens or closes the apparatus hermetically.
554
Experiments
It establishes or cuts off communication with the pump, and, when
the tube surmounting it is taken away, permits sudden decom-
pression of the air in the reservoir, when necessary.
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In the experiments in which I simply compressed the air, the
bag pictured in the figure was not present, of course, and the suc-
tion of the pump was directly outside.
Death in Closed Vessels 555
I used even more often an apparatus made in a similar manner,
whose reservoir was a simple receiver of a Seltzer water generator.
I could take this only to 10 atmospheres; but the rounded form of
the apparatus gave the animals more liberty.
Finally, I used a mercury bottle, mounted like the glass cylinder,
The extreme solidity of this instrument would have allowed me to
carry the pressure to 40 atmospheres without difficulty. Its capac-
ity of 3 liters also has great advantages; the only inconvenience is
that of not being able to see what is going on inside.
2. Experiments.
A. Compression with Ordinary Air.
I now come to the experiments. I shall list them, as I have done
hitherto, in the order in which they were performed. What I said
at the beginning of this sub-chapter indicates sufficiently why I
began with a pressure of 3.75 atmospheres. The apparatus which
I used in this first series is a Seltzer water receiver, of a total
capacity of 1060 cc.
Experiment LXXXIX. July 18; temperature 26°. House sparrow,
young. In 10 minutes the sparrow is taken to 3.75 atmospheres; it
does not seem affected; but, an accident making the pressure fall sud-
denly, it bristles up and hides its head under its wing. The increase
of the pressure to its original level restores its healthy appearance.
Cocks closed at 2 o'clock. At 2:20, sick; at 3:10, very sick; at
5:20, seems to be dying; at 6:30, the same. At 10 o'clock in the eve-
ning, thinking it dead, I withdrew air so that the pressure fell to 2
atmospheres; it was breathing then, and I left it until 10:30. Taken
out then, it was still living, with a rectal temperature of 28° (the
same temperature as that of the receiver) ; it died during the night.
The air which I took at 10 o'clock, and which probably would
have changed but little afterwards, contained: CCb 7.2; O2 11.1.
Experiment XC. July 19; temperature 25°. House sparrow, young.
In 10 minutes, taken to 7 atmospheres; closed the cock at 2: 10. At
4:45 very sick, eyes closed. At 10 o'clock in the evening, found dead.
I made the decompression rapidly and on examining the jugular
vein, I found the blood red and frothy like foam.
The lethal air contained CO2 3.7; O 16.2.
Experiment XCI. July 20; temperature 21.5. House sparrow,
young. Taken rapidly to 2V2 atmospheres. Closed cocks at 5:30.
Sick at 5:55; seemed dead at 9:45. I took out an air sample and
opened the apparatus.
Taking the bird in my hand, I perceived that it was still breath-
ing a little, and was still a little sensitive. The rectal temperature
was 23.5°, probably equal to that of the receiver. I cut its head off;
it had very energetic reflex movements. The bird therefore lived
556 Experiments
about 4V2 hours, in a quantity of air corresponding to 2.650 liters at
normal pressure.
The blood was very red in the left heart; less dark than in the
ordinary condition in the right jugular; no free gases in the blood.
Lethal air: CO* 11.2; O. 8.5.
Experiment XCII. July 21; house sparrow, young. Put in a pres-
sure of 5 atmospheres at 10 o'clock in the morning; found dead at 1
o'clock.
Lethal air: CO. 6.0; O 14.2.
Experiment XCIII. July 24; temperature 21°. House sparrow.
Placed in a pressure of 1V2 atmospheres at 5:10. Died at 8:45. Rectal
temperature 25.5°; venous blood fairly red; no free gases. Lived 3
hours 35 minutes in 1.580 liters of air, at normal pressure.
Lethal air: CCb 15.2; O* 2.6.
Experiment XCIV. July 25; temperature 23°. House sparrow,
rather old. At 4:35 taken to 2 atmospheres. Found dead at 7:45.
Lethal air: CCh 13.7; O? 5.0.
Experiment XCV. July 26; temperature 23°. House sparrow. At
1:25, taken to 5 atmospheres.
Died at 4:15. Rectal temperature 23°; blood and tissues red; the
heart was still beating after removal. Lived 2 hours 50 minutes in
the equivalent of 5.300 liters of air.
Lethal air: CO 5.1; O* 13.4.
Experiment XCV I. August 4. House sparrow. At 4:35 taken
to 6 atmospheres. At 5:30, very sick; found dead at 9:30. Venous
blood red; gas in the right heart and the jugulars, but not in the left
heart.
Lethal air: CO2 4.2; O 16.0.
Experiment XCVII. August 11. House sparrow. At 2:55, placed
at IV2 atmospheres. Very sick at 5:30. Found dead at 9 o'clock;
venous blood, dark.
Lethal air: CO* 15.4; O2 2.5.
Experiment XCVIII. August 17. Yellow-hammer (Emberiza cit-
rinella, Lin.). At 4:45, at 1 and % atmospheres. Sick at 6 o'clock;
found dead at 8 o'clock; venous blood dark; no gases.
Lethal air: CO2 12.9; O* 4.9.
Experiment XCIX. August 19; 22°. Linnet (Fringilla cannabina,
Lin.).
Taken to 8.8 atmospheres. Closed the cock at 2:50; at 3:45, dis-
tressed, made efforts to vomit. At 4:45, fell on its side, respirations
grew slower and weaker; no convulsions. At 6 o'clock a quivering
in one foot, then extension: it was the last movement.
Rectal temperature 25.5°. The venous blood was very red, with-
out gas; the heart was still beating, auricles and ventricles. Lived
3 hours and 10 minutes in 9.330 liters of air at normal pressure.
Lethal air: CO* 2.8; O* 17.4.
Death in Closed Vessels
557
Experiment C. August 19; temperature 22°. Linnet.
At 6:20, taken to 95 centimeters pressure; at 9:55, found dead.
Venous blood dark, without gas.
Lethal air: CO* 13.3; O* 3.7.
Experiment CI. August 20; mountain sparrow. Placed at llA
atmospheres.
Lethal air: CO= 14.3; O* 3.4.
The results of these experiments are grouped in the increasing
order of pressures in the following table.
Table V
1
2
3
4
5 •
6
7
8
9
10
n
01
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13.3
3.6
15.6
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77
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26.1
14.3
3.4
17.9
4.2|17.7
81
XCIII
1.5
3h 35m
2h 15m
31.3
15.2
2.6
22.8
3.9|17.8
83
XCVII
1.5
31.3
15.4
2.5
23.1
3.7117.9 83
XCVIII
1.75
from 2 to 3 h.
36.5
12.9
4.9
22.5
8.6|17.8|80
XCIV
2
less than 3 hr.
41.8|13.7
5.0
27.4
10 118.7186
XCI
2.5
4h 30m
| lh 42m|
52.2|11.2|
8.5|28.0
21.2|19.7|90
LXXXIX
3.75
more than 8 h.
78.3| 7.2
11.1
27.0
41.3
18.3|73
XCII
5.0
2h 55m
33m
104.5
5.5
13.8
27.5
69
77
xcv
5.0
XCVI
6
125.4
4.2
16.0
25.2
96.0
20.2
85
xc
7
146.3
3.7
16.2
25.9
113.4
19.9178
XCIX
8.8
3h 10m
20m
183.9
2.8
17.4
24.6
153.1
20.2180
If now we consider these results, occupying ourselves first with
the composition of the air which had become irrespirable — and the
preceding table makes this bird's-eye view easy — we see at once
that the hypothesis suggested as a heading for this sub-chapter,
far from being verified, is exactly opposite to the truth. The
greater the pressure, the less the oxygen of the air was exhausted,
as Column 7 of Table V shows. At 8.8 atmospheres, the highest
pressure I used in this first series of experiments, there remained
after death 17.4 per cent of oxygen.
This observation, already strange, becomes absolutely aston-
ishing when we take account not only of the figure expressing the
percentage, but also the number, hitherto constant in our experi-
ments, which indicates the oxygen tension in the lethal air. We
saw in the first chapter that this number oscillates between 3 and 4.
558 Experiments
In the present experiments, Column 9 furnishes us analogous fig-
ures only for the pressures between 1 and 2 atmospheres. And
even here there appear already the numbers 8 and 10, which soon
become 20 and 40, and finally 113 and 153 at the pressures of 7 and
8.8 atmospheres.
So then, above 2 atmospheres, death in confined air cannot be
attributed to lack of oxygen; we must seek some other cause.
My first thought naturally turned to carbonic acid.
Now considering Column 8, in which are listed numbers ob-
tained by multiplying the percentage of carbonic acid by the num-
ber of atmospheres, and which consequently represent the car-
bonic acid tension in the lethal air, we see that, from 2 atmospheres
on, these numbers oscillate between 25 and 30.
If now we refer to what M. Claude Bernard" said formerly about
the conditions of death of birds confined at normal pressure in
superoxygenated air, we see that they die when they have formed
a proportion of carbonic acid which corresponds precisely to that
which we have just indicated. The numerous experiments which
I myself4 have carried on in this field have led me to similar results,
and I have confirmed the accuracy of the explanation given by
CI. Bernard of this strange asphyxia in a medium much richer in
oxygen than ordinary air. It is a real poisoning due to the carbonic
acid of the blood, which cannot be eliminated because of the
pressure exerted upon it by the carbonic acid contained in the
ambient atmosphere.
The cause of death, then, is the pressure exerted by this carbonic
acid, a pressure measured exactly at one atmosphere by the per-
centage of carbonic acid present. At pressures above one atmos-
phere, the real pressure, the tension of the carbonic acid, is
obtained by multiplying the percentage by the number of atmos-
pheres, and in this way we obtained the figures in Column 8.
We can now give, for death in closed vessels, at pressures greater
than one atmosphere, a formula quite analogous to the one wa
gave earlier (see page 552) for pressures lower than one atmos-
phere, and say: The death of sparrows occurs when the tension
of the carbonic acid, measured as I have just specified, is repre-
sented by a figure which oscillates between approximately 24 and
30; hereafter we shall take 26 as an average number.
The result of this fact is that, if we represent our results by a
curve resembling that of Figure 17, in which the abscissae would
represent the pressures, and the ordinates the proportions of car-
bonic acid, this curve would correspond to the formula xy = 25 to
Death in Closed Vessels 559
30, and consequently would also be a branch of an equilateral
hyperbola.
But we must note immediately that this formula begins to be
true only from IV2 and especially from 2 atmospheres. Below
that, the figures of Column 8 are much lower. In this case the
quantity of oxygen at the bird's disposal was not sufficient to per-
mit the production of a quantity of carbonic acid fatal in itself.
Of course the carbonic acid tension was not negligible, especially
when it reached the value of 22 or 23; but in this case we must
take into account the exhaustion of the oxygen, whose very ad-
vanced state is shown us by Column 9. In fact, we find here again
the figures varying from 3 to 4, which we recognize as expressing
the oxygen tension which is too low to support life.
Influence of the temperature. The preceding results were ob-
tained at temperatures above 20°. I wished to find out whether
considerable cold would have much effect on the figures obtained.
Here is what occurred.
Experiment CII. December 12; temperature of the laboratory
+ 6°. House sparrow. Placed at a pressure of 6 atmospheres; closed
cocks at 2 o'clock. Surrounded the apparatus completely with a mass
of snow at 0°.
At 4:20, sparrow found dead. At 4:25, his rectal temperature was
+ 4°.
Lethal air: CO.- 2.9; O* 17.4.
CO. x P = 17.4.
Experiment CHI. December 13; temperature +6°. House sparrow.
At 2 o'clock, placed at 5 atmospheres. Surrounded the apparatus with
a mixture of ice and salt whose temperature dropped to 2°. The inside
thermometer could not be read. At 3:35, found dead. Rectal tempera-
ture, +8°; venous blood red, without gas bubbles.
Lethal air: CO. 3.4; O. 15.2.
CO. x P = 17.0.
Experiment CIV. December 14; outside temperature +5°. House
sparrow. At 2:50, taken to 4 atmospheres. Surrounded by a mixture
of ice and salt.
At 4:20, very sick; at 4:30, dead. Inside temperature of apparatus
+1°; rectal temperature, -\-11.5°.
Lethal air: CO. 5.0; O. 13.3.
CO, X P = 20.
We see that the effect of the cold was very important, and that
the birds could not in these conditions form as much carbonic acid
as at high temperatures. That is easily understood, because of
the chilling of the animal, which was not compatible with the
560 Experiments
exercise of the bodily functions and no longer permitted respira-
tory movements.
I even think that it is to the temperature that we must attribute
results somewhat different from those I reported above, obtained
with the same apparatus, but during a cooler season.
Experiment CV. January 31. House sparrow. At 3:50, taken to 4
atmospheres. Died at 5:50. No cranial suffusions.
Lethal air: CO* 5.8; O* 13.2.
CO x P = 23.2.
Experiment CVI. March 18. House sparrow. At 2: 10 taken to 6
atmospheres. Very sick at 3:30; found dead at 4:50. Red dots on
cranium.
Lethal air: CO. 3.9; O* 14.9.
CO* x P = 23.4.
B. Superoxygenated air: pressures below one atmosphere.
It is here that I think I should place the account of the experi-
ments made by the method discussed on page 536 (Sub-chap. 1), in
which the sparrows were kept in closed vessels, at pressures less
than one atmosphere, but in superoxygenated air. Here, down to
the low limits indicated, death took place not through too low
oxygen tension but through too high carbonic acid tension, that
is, through a mechanism identical with the one we are discussing
now.
Here are the details of these experiments, all made with spar-
rows; the first two are a repetition of the classic experiments of
Claude Bernard.
Experiment CVII. January 16. Bell-jar of one liter.
The bird was brought successively three times to a 40 cm. drop
in pressure, the pressure each time being restored to normal by the
admission of oxygen. The, mixture then contained 91 per cent of
oxygen. I left the bird at normal pressure, and closed the cocks at 3
o'clock.
Died at 6:15; lived 3 hours 15 minutes.
Lethal air: CO* 24.8; O* 64.5.
CO= + O2 = 89.3. The ratio of the carbonic acid formed to the
oxygen consumed was:
CO, 24.8
= = 0.93.
O2 26.5
Experiment CVIII. January 16. Bell- jar of 1 liter.
Brought three times in succession to a 40 cm. drop in pressure;
actual pressure, 36 cm.
Closed cocks at 2; 30; death at 6:15. Pressure 34 cm. Original mix-
ture: O* 82,
Death in Closed Vessels 561
Lethal air: CO. 63.3; O 17.5.
CO + Oa = 80.8; CO. = 0.98. CO=xP = 28.3.
Experiment CIX. January 29. Bell-jar of 675 cc; mountain spar-
row.
Pressure lowered 50 cm., the bird became sick; oxygen admitted;
second decompression carried to 60 cm., sick; oxygen admitted. Closed,
cocks at 3:35.
Left at normal pressure. At 5 o'clock, panting; at 6 o'clock, died
without convulsions; a slight bloody suffusion on the cranium.
Lethal air: CO* 24.8; O. 63.3.
Experiment CX. January 30. Bell-jar of 1.3 liters.
Pressure lowered 44 cm., 58 cm., 36 cm., then 48 cm. Closed cocks
at 3:50; dead at 6 o'clock.
The inner pressure was 25 cm.
Original mixture: O. 89.2.
Lethal air: CO. 72.1; O. 15.3.
CO.
CO. -!- O* = 87.4; = 0.97.
O.
CO. tension: 23.7.
26
Oxygen tension: 15.3 x — = 5.0.
76
Experiment CXI. January 31. Bell-jar of 675 cc.
Pressure lowered 40 cm., 50 cm., 50 cm., and compensated by oxy-
gen. The last time, the pressure was lowered 55 cm. Closed cocks at
3:20. Died at 5:15; no bloody suffusions on the skull.
Original mixture: O. 79.6.
Lethal air: CO. 35.3; O. 42.3.
CO.
CO. + O. = 77.6; = 0.94. CO. x P = 25.5.
O.
Experiment CXII. January 31. Bell-jar of 1.3 liters.
Pressure lowered 40 cm., 50 cm., 50 cm., the last time, 43 cm.
At death, the pressure is only 36 cm.
Original mixture: O. 89.8.
Lethal air: CO* 57.6; O. 30.1.
CO.
CO. + O. = 87.7; = 0.96. CO. x P = 27.2.
O.
Experiment CXIII. February 2. Bell- jar of 1.350 liters.
Pressure lowered 30 cm., 50 cm., then 50 cm., and compensated by
oxygen; the last time pressure lowered 58 cm.
Closed cocks at 3:45; died at 6:45; the pressure was lowered only
51 cm.
562 Experiments
Original mixture: O* 91.5.
Lethal air: CO 36.0; O* 54.9.
CO
CO + O* = 99.6; = 0.98. CO x P = 24.2.
O
Experiment CXIV. February 5. Bell-jar of 1.3 liters.
Pressure lowered 30 cm., 50 cm., 50 cm., the fourth time left at
45 cm.
Entered at 4 o'clock. Dead at 8:15; the pressure was 38 cm.
Lethal air: CO* 49.3; O 36.6.
CO x P = 24.6.
Experiment CXV. February 6. Bell- jar of 675 cc.
Pressure lowered successively 30 cm., 50 cm., and 50 cm., and
compensation made each time with oxygen. Closed cocks at 2:35; the
pressure was 57 cm. Dead at 5:45. Cranial suffusions in places.
Actual pressure 55 cm.
Mixture before the experiment: O* 87.8.
Lethal air: CO> 36.3; O 50.1.
CO>
CO + O = 86.4; = 0.97; CO* x P = 26.2.
O*
Experiment CXVI. February 19. Bell-jar of 675 cc.
Pressure lowered once 30 cm., and twice lowered 50 cm.; each
time, oxygen admitted. Actual pressure finally 64 cm. Closed the cocks
at 1:50.
Dead at 3:35; little bloody mottlings on the cranium. Jugular
blood red.
Lethal air: CO* 27.7; O* 54.7.
64
The CO* tension is CO* x P = 27.7 x = 23.3.
76
Experiment CXVII. February 19. Bell-jar of 1.35 liters.
Pressure lowered 30 cm., 50 cm., 50 cm.; the last time left at 46
cm.
Cocks closed at 2 o'clock; at 4:15, very sick. At death, the pres-
sure is 43 cm. Slight cranial suffusions.
Lethal air: CO* 42.4; O* 29.8.
CO* x P = 24.5.
Experiment CXV III. February 19. Bell-jar of 2.2 liters.
Pressure lowered 30 cm., 50 cm., 50 cm., then to 34 cm. of actual
pressure.
Closed at 2:15; died at 6:45; enormous cranial suffusions.
Actual pressure, 29 cm.
Lethal air: CO* 66; O* 13.1.
CO* x P = 25.2.
29
The pressure of the oxygen remaining is only 13.1 x — = 5.
76
Death in Closed Vessels
563
Experiment CXIX. February 22. Bell-jar of 2.5 liters.
Pressure lowered 30 cm., 50 cm., 50 cm., then to 38 cm. Closed
at 1:05. Dead at 7 o'clock. Slight suffusion on the cranium; venous
blood red.
Actual pressure, 34 cm.
Lethal air: CO 60; O 27.4.
CO x P = 26.8.
All these results are summarized and grouped, following the
descending order of barometric pressures, in the following table;
I have added to it the experiments reported on page 537.
Table VI
1
•2
3
4
5
G
7
8
9
o
c
~o~
o
II
P
ID
>1
X
o
Compos
tion of
6
u
c
El
« £
Crt
CO £
leth
jl air
Ofc
jjfc
X2 l~
S3
ftia
S§
^ 1 N
C X
c x
Sa
M'tfi
8[°
o M
MO
£W
ffl &
OO
02
co2
oa
S"
h
O
CVII
76 cm.
91
91
24.8
64.5
0.93
24.8
64.5
CIX
76
91
91
24.8
63.3
0.93
24.8
63.3
CXVI
64
91
91
27.7
54.7
0.93
23.3
46.0
cxv
55
87.8
63.5
36.3
50.1
0.97
26.2
36.2
CXI
55
79.6
57.6
35.3
42.3
0.94
25.5
30.6
CXIII
51
91.5
61.4
35.7
54.9
0.98
24.2
36.8
CXVII
43
91.5
61.4
42.4
29.8
0.98
24.5
16.8
CXIV
38
91.5
61.4
49.3
36.6
0.98
24.6
18.3
CXII
36
89.8
45.9
57.6
30.1
0.96
27.2
14.2
CVIII
34
82
36.7
63.3
17.5
0.98
28.3
7.8
CXIX
34
82
36.7
60
27.4
0.98
26.8
12.2
CXVIII
29
82
36.7
66
13.1
0.98
25.2
5.0
ex
25
89.2
29.3
72.1
15.3
0.97
23.7
5.0
XLVII
18
85.9
20.3
68.1
15.4
0.96
15.2
3.6
XLVIII
14
85.9
20.3
48
23.8
0.96
| 8.8
4.3
XLIX
12.5
88.4
14.5
66
22.2
0.99
10.8
3.6
L
8
82.3
8.6
37.2
41.8
0.92
1 3.9
4.4
LI
| 6.6
87
7.5
17.3
66.7
0.85
1 1.5
5.8
In this table a glance at Columns 5 and 8 are enough to prove
that our expectations are realized and that, at these pressures less
than one atmosphere, poisoning by carbonic acid comes when the
tension of this gas can be expressed by numbers varying from
24 to 27. That is the result obtained earlier for pressures greater
than IV2 atmospheres.
This is deduced, as Column 5 shows, from the proportions of
carbonic acid which may rise to 72 per cent. At very low pressures,
below 20 centimeters, for example, the law below no longer holds;
but that is easily understood. Let us take, for example, the pressure
564 Experiments
of 14 centimeters, noted in Experiment XLVIII. To reach the
average figure of 26, the percentage of carbonic acid in the lethal
76
air must rise to 26 x — = 141, which is evidently impossible. In
14
other words, before the bird can reach the lethal tension of carbonic
acid, it exhausts the oxygen of the surrounding medium, so that it
succumbs to the kind of death customary in diminished pressures,
when ordinary air is used. That is why we shifted to Sub-chapter
I the experiments made under these conditions.
The analogy between these two kinds of experiments, apparently
so different, is seen again in a rather interesting experimental de-
tail, which, at first glance, seemed to me somewhat paradoxical.
When I supplied pure air to a bird which was beginning to suffer
from the effect of increased pressure, I did not relieve it at all;
on the contrary, an evident improvement appeared when I allowed
a part of its air to escape. This is easily explained; let us suppose
that the bird is under a pressure of 3 atmospheres and that it has
already formed 6 per cent of C02; the pressure of this gas, 6 x 3=18,
is enough to make the bird ill. If I admit 3 atmospheres of pure
air, the C02 tension becomes 3 x6=18, that is, it does not change
at all, since although the pressure increases one-half, the percentage
diminishes one-half; the bird is therefore not relieved. If, on the
contrary, I let out one-half of the air, the tension becomes 6 x 1.5
=9, so that an immediate betterment results. So this apparent
paradox confirms again, in an indirect way, what I have already
demonstrated.
The same thing holds good for experiments at low pressures
with a superoxygenated atmosphere. Here, if the bird has been
made ill by the carbonic acid it has formed, it is not relieved if air
or oxygen is admitted; on the contrary, if the barometric pressure
is lowered, it is relieved. Let us take the case of a bird at 38 cm.,
that is, at a half-atmosphere. Let us assume that it has already
formed 30 per cent of CCX; the CO, tension is 30 x ¥2 =15 and the
bird begins to suffer from it. Let us admit air until the pressure
is 57 cm., that is, three-quarters of an atmosphere. The percentage
will be only 30 x %=20, but the tension will be 20 x 3/4 = 15, and
the bird will be in the same state as before. If, on the contrary,
we remove air and drop the pressure, for example, to 19, V\ of an
atmosphere, the percentage of carbonic acid will not have changed,
and its tension will be only 30 x 1/4=7.5, a tension almost harmless
to the bird, which will be relieved immediately.
Death in Closed Vessels 565
C. Compressed air at very high pressure: fatal action of oxygen.
The study of the alterations of compressed air which has be-
come lethal through confinement was to give me a result that was
interesting in a very different way.
When we examine carefully Column 8 of Table V, we see that,
from 6 atmospheres on, the number of the carbonic acid tension
is a little lower than one finds at a pressure from 2 to 5 atmos-
pheres, and seems to continue diminishing as the pressure in-
creases. This slight difference did not impress me at first; but
when I made experiments at pressures higher than those of Table
III in the cylindrical glass reservoir capable of supporting a pressure
of 25 atmospheres, I obtained numbers which showed me the ap-
pearance of a new element in the question.
Here is the report of these experiments.
Experiment CXX. April 16.
Linnet; taken to 20 atmospheres, from 4:55 to 5:10.
Slight convulsions appear at 5:15; the feet, the head, the body
quiver in spasms. Dies at 5:35. Lived 25 minutes.
Lethal air: CO* 0.4.
CO* x P = 8.
Experiment CXX I. April 23.
Sparrow; at 9:45 taken to 6 atmospheres. Dies at 11:10; lived
about 1 hour 20 minutes.
Lethal air: CO* 3.5; O* 16.
CO* x P = 21.0.
Experiment CXX II. April 23.
Sparrow; taken at 3:10 to 3 atmospheres. At 4:05, very sick; at
4:50, dying. Dead at 5 o'clock; lived about 1 hour 50 minutes. Spot on
the scalp; dark blood in the jugular; no gas.
Lethal air: CO* 7.8; O* 10.7.
CO* x P = 23.4.
Experiment CXXIII. April 24.
Mountain sparrow; taken at 1:40 to 5 and % atmospheres. At 3
o'clock still alive; found dead at 3:50; lived about 1 hour 30 minutes.
Large scalp suffusions.
Lethal air: CO2 3.8; O* 15.5.
CO* x P = 21.8.
Experiment CXXIV. April 26.
House sparrow; at normal pressure has respiratory rate of 144.
Taken to 3 atmospheres at 1 o'clock; respiratory rate 132. At 1:03, to
6 atmospheres, respiratory rate, 130; at 1:06, to 9 atmospheres, respir-
atory rate 120. Closed the cocks; at 1:11, respiratory rate 106; at 1:20,
80; at 1:50, 50, very sick; found dead at 2:25. Lived about 1 hour 10
minutes.
566 Experiments
Red blood in the jugular; bloody suffusions on the scalp.
Lethal air: CO 2; O 17.5.
CO* x P = 18.
Experiment CXXV. April 26.
'House sparrow; at 4:23, normal pressure, respiratory rate 135.
Began the compression. At 4: 27, 6 atmospheres, respiratory rate 96.
At 4:29, 9 atmospheres, respiratory rate 90; at 4:31, 12 atmospheres,
respiratory rate 90. At 4:53, very sick. Each inspiration, which is very
deep, is accompanied by a quivering of the wings. At 5:10, still a
few respirations; at 5: 15, dies.
Lived 45 minutes. Scalp suffusions in spots; red blood in the
jugular.
Lethal air: CO* 1.2; O 18.4.
CO* x P = 14.4.
Experiment CXXVI. May 7.
Sparrow taken to 15 atmospheres; closed cocks at 2:15. At 3:20,
found dead.
Lethal air: CO* 0.8; Cb 19.5.
CO x P = 11.2.
Experiment CXXV II. May 17.
Sparrow at 4 atmospheres; closed cocks at 4:45.
Sinks down at 5:34; dies at 6:20. Lived 1 hour 35 minutes. Red
foam on the beak; scalp suffusions in blackish patches; venous blood
of normal color; no gas.
Lethal air: CO 5.6; Cb 13.2.
CO* x P = 22.4.
Experiment CXXV III. May 18.
Sparrow at 8 atmospheres; 3:17.
Dead at 4:55; lived 1 hour 38 minutes. Red foam on the beak;
bloody suffusions in reddish patches; venous blood red and containing
some gas.
Lethal air: CO* 2.4; O 16.8.
CO x P = 19.2.
Experiment CXXIX. May 21.
Sparrow at 14 atmospheres; closed the cock at 4:55. Found dead
at 6 o'clock; lived less than one hour.
Venous blood very red, with gas. Scalp suffusions very extensive.
Lethal air: CO 0.9; O 18.5.
CO2 x P = 12.6.
Experiment CXXX. May 22.
Sparrow; at 12 atmospheres, at 2:45. Found dead at 3:40; lived
less than 55 minutes.
Red blood in the jugular, with gas. Scalp suffusions.
Lethal air: CO 1.3; O 19.1.
CO* x P = 15.6.
Death in Closed Vessels
567
Experiment CXXXI. June 18.
Sparrow; taken to 14 atmospheres at 3:33. Dead at 4:12. Lived 39
minutes. Struggling, but no convulsions.
Venous blood very red, with gas. Scalp suffusions very extensive,
of a bright red.
Lethal air: CO* 0.93.
CO* x P = 13.2.
Experiment CXXXII. June 19.
Sparrow; taken at 3:04 to 2 atmospheres. Dead at 6:53 without
convulsions, without foam on the beak; lived 3 hours 49 minutes. The
cranial diploe contains bloody suffusions in small blackish patches.
The color of the venous blood is normal; no gas.
Lethal air: CO* 12.6; O* 3.2.
CO* x P = 25.2.
Experiment CXXXIII. June 19.
Sparrow; taken to 17 atmospheres from 2:04 to 2:15. Dead at 2:54.
Lived 39 minutes; respiration very slow, no convulsions, red froth on
beak.
Very extensive bloody suffusions; venous blood very red, con-
taining much gas.
Lethal air: CO* 0.6; O* 18.6.
CO* x P — 10.2.
Table VII
1
2
3
4
5
6
7
8
9
10
in 4>
<w U
0*3
a
o
'55
c
*^ 4J
Composition of
d.
SI
.o u
C 41
2w
u
3
41
Po
.2 il o
co^-1 to
3S^
P an
2 >>
.5 x
mO
Oo
lethal air
6
u
6
8 Id
CO,
o3
1
h. m.
h. m.
CXXXII
2
3 49
3 4
41.8
12.6
3.2
25.2
6.4
0.72
CXXII
1 3
1 50
1
62.7
7.8
10.7
23.4
32.1
0.75
CXXVII
4
1 35
39
83.6
5.6
13.2
22.4
52.8
0.72
CXXIII
5 %
1 30
27
120.1
| 3.8
15.5
21.8
89.1
0.70
CXXI
1 6
1 20
22
125.4
| 3.5
16
21.0
96
0.71
CXXVIII
8
1 38
20
167.2
2.4
16.8
19.2
134.4
0.60
CXXIV
9
1 10
14
188.1
2
17.5
18.0
157.5
0.59
cxxv
12
45
6
250.8
1.2
18.5
14.4
222.8
0.50
cxxx
12
45
1
250.8
1.3
18.7
15.6
224.4
0.59
CXXIX
14
45
1
292.6
0.9
18.5
12.6
263.2
0.43
CXXXI
14
39
4
292.6
0.9
18.5
13.2
263.2
0.43
CXXVI
15
39
1
313.5
| 0.8
19.4
11.2
291
0.53
CXXXIII
17
39
3
355.3
| 0.6
18.8
10.2
319.6
0.30
cxx
| 20
25
2
418.0
| 0.4
18.8
8
319.6
0.30
Before passing to the study of the results of these experiments,
grouped in Table VII in increasing order of pressure, I think I
should call attention to the fact that the preceding analyses of the
568
Experiments
gases were made meticulously from a very special necessity which
is easily seen. In fact, the least error in the calculation of the
proportion of carbonic acid would cause an enormous error in the
product C02 x P in the high pressures. The agreement in the
results announced, on which I shall dwell now, is only the more
remarkable.
A glance at Column 8 of the table, which contains the numbers
expressing the carbonic acid tension in the air which had become
■
■i
■
||
n
a
s
Bi
1 EZi
Fig. 21 — Confined air which has become lethal under pressure; carbonic
acid content: A, calculated proportions; B, proportions found
experimentally; C, superoxygenated air.
irrespirable, completely confirms the suspicions which we had con-
ceived on examining Table V in points relating to high pressures.
In fact, the number CO, x P, when closely inspected, is never
constant. It diminishes from 3 atmospheres on, and this diminu-
tion is extremely rapid beginning with 8 atmospheres.
Death in Closed Vessels 569
The smaller and smaller quantity of carbonic acid, following
the law expressed above, is shown very clearly in the graphs in
Figure 21, in which the quantity of carbonic acid is measured on
the vertical axis, while the atmospheres are reckoned on that of
the x's. The solid line B expresses the figures of Column 6, and the
dotted line A connects the points which are calculated from the
equation CO, x P = 26, an average number taken from Table VI,
26
whence CO., = — . This line, like that of the lethal proportions of
P
oxygen in low pressures, is a branch of equilateral hyperbola, hav-
ing the coordinates as asymptotes.
This constant drop of the graph below the curve which the
theory indicates led me to think of the intervention of another
agent than carbonic acid. Tentative experiments had already
shown me that oxygen under a certain pressure is a cause of symp-
toms and death. Its fatal effect seemed manifest to me here.
Before trying to render this prime factor evident, I wish to call
attention to a secondary point, which is, however, quite interesting.
Columns 3 of Tables V and VII show that, disregarding a few
exceptions which are hard to explain, the duration of life from 1
to 9 atmospheres did not increase with the pressure, or, in other
words, with the quantity of air which the birds had at their dis-
posal. And that is easily understood, since they did not die from
having exhausted this air, but simply when they had formed a
certain quantity of carbonic acid always the same, or approximately
so. The annoying interference of the oxygen which I have just
mentioned even lessens the duration of life, as is clearly seen from
10 atmospheres on; death comes very quickly at very high
pressures.
This is manifest in quite another way when we compare the
duration of life not to the volume, but to the actual quantity of air
contained in the receiver, or, which amounts to the same thing, to
a liter of air at normal pressure; the duration of life is then ex-
pressed by numbers which decrease with a truly extraordinary
rapidity. This is shown by Columns 4 of Tables V and VII; we see
that, even at 4 atmospheres, the duration of life is reduced by about
one-half, and that at 20 atmospheres, it is only 2 minutes per liter
instead of 76 minutes, as we found it at normal pressure (See Table
I, Column 7). This enormous difference cannot be attributed to
the carbonic acid, whose tension diminishes equally; another factor
570 Experiments
evidently interferes here, and this dangerous factor is nothing but
oxygen.
D. Compression with air of low oxygen content.
Let us now examine this hypothesis of a fatal action of the
compressed oxygen with the effect of killing the bird before it has
formed the percentage of carbonic acid required by the formula
C02 x P = 26. Let us refer to Table VII. If the explanation I have
just given of the lowness of the numbers of Column 8 (C02 x P)
measuring the tension of the carbonic acid is correct, that is, if this
lowness is due to the high value of the numbers of Column 5
(02 x P) , measuring the oxygen tension, the first will increase if
I lower the second by lessening the factor O. without changing
factor P.
It was enough then to repeat the experiments, injecting into the
compression apparatus not ordinary air, but air of low oxygen
content. This was done in the following experiments.
Experiment CXXXIV. April 20.
Greenfinch (Loxia chloris, Lin.) Put into the apparatus for 5
minutes, then raised to 6 atmospheres of air; cock closed at 2:50. At
3 o'clock, we began to inject air very low in oxygen, and at 3:11,
reached 22 atmospheres.
The moment of death cannot be clearly determined, but the bird
had no convulsive movements at any time.
Considerable cranial suffusions.
Lethal air: CO^ 1.1; O* 9.
Initial oxygen tension: 226.
* Final CO tension: 24.2.
Experiment CXXXV. June 27.
A sparrow is placed in the apparatus, and air in which phosphorus
has burned and which has become very low in oxygen is pumped in;
the pressure is taken to 5 atmospheres.
The cock is closed at 3:55; the bird dies at 5:50. It lived therefore
1 hour 55 minutes; bloody suffusions, not very extensive; some gas
bubbles in the right heart.
Composition of lethal air: CO 4.5; O 5..
Initial oxygen tension: 50.
Final CO- tension: 22.5.
Experiment CXXXVI. June 29.
Sparrow at 12 atmospheres, 1 of air and 11 of air in which phos-
phorus has burned.
Entered at 2:45; dead at 3:15; lived 30 minutes; cranial suffu-
sions; gas in the right heart.
Lethal air: CO* 2.1; O 4.8.
Initial oxygen tension: 84.
Final CO tension: 25.2.
Death in Closed Vessels 571
These results entirely justify our explanation, and show that
the decrease of the product CO, x P, when the pressure increases,
must be attributed to the intervention of the oxygen playing a fatal
part.
We see furthermore that the points a and b, which represent
on Figure 21 the numbers furnished by Experiments CXXXIV and
CXXXVI, are placed very exactly on line A, which was plotted
according to the theory.
E. Compression with superoxygenated air.
This fatal effect of oxygen under a sufficiently high pressure
was so remarkable a phenomenon that I felt I must try to exhaust
all means of proving it indisputably.
Now a new method occurred to me, the opposite of the one
which has just been used. I had only to make the compression with
superoxygenated air, still in closed vessels. The influence of oxy-
gen, if it is as serious as I thought, should bring death to animals at
a moment when they were far from having furnished the same
percentage of carbonic acid as at corresponding pressures in the
case of ordinary air. This, indeed, happen in the following ex-
periments.
Experiment CXXXVII. January 16.
Sparrow at 5 atmospheres, 4 of which are oxygen.
Entered at 3:25; at 3:40, falls with violent convulsions; at 3:48,
on its back; the cranium, previously bared of feathers, shows abun-
dant bloody suffusions. At 4:35, still breathes slowly; the convulsions
lasted about 15 minutes.
At 4:50, dead. Rectal temperature is 18°, that of the laboratory
air being 9°. Venous blood red; no gas; the heart is beating when
in the outer air.
The original mixture contained O: 83.
The tension of this oxygen = 83 x 5 = 415, corresponding to that
of 415 = 19.7 atmospheres.
20.9
Lethal air: CO 1.4; Oi 80.5.
CO2 tension = 1.4 x 5 = 7.0.
Experiment CXXXVIII. January 17.
At 3:30 taken to 3 atmospheres, 2 of which are oxygen.
At 3:50 breathes with great difficulty; uneasy. At 4:45, dead.
Lethal air: CO 5.6; Cb 78.9.
CO? tension = 5.6 x 3 = 16.8.
The tension of the original oxygen was about 86 x 3 = 258, corre-
sponding to 12.1 atmospheres,
572 Experiments
Experiment CXXXIX. January 19.
The sparrow being in the apparatus, a little air was removed by
the pump, and replaced by oxygen which was raised to 2 atmospheres.
When air was taken for analysis, the pressure fell to 1 and % atmos-
pheres.
Closed cocks at 2:40; dying at 4:45; found dead at 5:30.
Original mixture contains 83.6 per cent of oxygen.
Tension of this oxygen = 83.6 x 1.75 = 146.3, which corresponds
to 7.3 atmospheres.
Lethal air: CO 11.9; 0= 67.8.
CO2 tension = 11.9 x 1.75 = 20.8.
Experiment CXL. January 22.
Put at 2 atmospheres, one of which is oxygen.
Entered at 3:05; at 5:30, still breathing; found dead at 6:30.
The original mixture contains O2 58.8.
The oxygen tension was 117.6, corresponding to 5.6 atmospheres.
Lethal air: CO 13.4; O2 44.4.
CO tension = 13.4 x 2 = 26.8.
Experiment CXLI. February 1.
Raised to 4 atmospheres, 3 of which are oxygen. After about a
half hour, slight convulsions; dies in about an hour.
Cranial suffusions and venous blood very red; no gas in the blood.
Original mixture: O2 75.6.
Tension of this O2 = 75.6 x 4 = 302.4 corresponding to 14.4 atmos-
pheres.
Lethal air: CO2 2.1; O2 71.1.
CO2 tension = 2.1 x 4 = 8.4.
Experiment CXLII. February 17.
Raised to 5 atmospheres of air, to which are added 3 V2 atmos-
pheres of oxygen. After 5 minutes, convulsions ensue; the bird dies
in 20 minutes.
Blood red everywhere, even in the liver; no gas (cranium not
examined).
Lethal air: CO2 0.8; O2 47.8.
CO2 tension = 0.8 x 8.5 = 6.8.
The oxygen tension in the original mixture must have been about
51 x 8.5 = 433.5, corresponding to 20.7 atmospheres.
Experiment CXLIII. February 19. Seltzer water apparatus.
Put into the air to which V4 atmosphere of oxygen was added;
closed at 4:25; dead about 6 o'clock.
No bloody suffusions on the cranium; venous blood black.
Lethal air: CO2 22.1; O2 3.5.
CO2 tension = 22.1 x 1.25 = 27.6.
The original oxygen tension must have been about 26 x 1.25 = 32.5,
which corresponds to 1.5 atmospheres.
Experiment CXLIV. February 20.
I atmosphere of air; plus V2 of oxygen.
When the bird, thought dead, is withdrawn, it still exhibits some
Death in Closed Vessels
573
slight respiratory movements. Red blood in the jugular. Red spots
in the cranial diploe.
Lethal air: CO* 16.7; O 28.6.
CO* tension = 16.7 x 1.5 = 25.1.
The original oxygen tension must have been about 46 x 1.5 = 69,
corresponding to 3.3 atmospheres.
Experiment CXLV. February 20.
At 5V2 atmospheres, 4 of which are oxygen.
After 5 minutes, trembles, the head oscillates. After 10 minutes
great convulsions, the feet are doubled against the belly; the convul-
sions last 5 to 10 minutes, then the feet stretch out repeatedly. The
bird remains prostrated; after 20 minutes, dead.
Enormous cranial suffusion. Rectal temperature 26.5°.
Lethal air: CO* 1; O* 82.5.
CO* tension: 5.5.
The oxygen tension in the original mixture was about 85 x 5.5 =
467.5, corresponding to 22.3 atmospheres.
Experiment CXLVI. February 22.
Raised to 2V2 atmospheres, of which V2 is oxygen.
Closed at 12:55; dead at 3:55. Bloody suffusions in the thickness
of the cranial diploe; red blood in the jugular vein, rapidly becomes
black.
Lethal air: COa 11.1; O* 33.3.
CO* tension = 11.1 x 2.5 = 27.7.
The original oxygen tension was about 46 x 2.5 = 115.5, which
corresponds to 5.5 atmospheres.
The results of these experiments are grouped in Table VIII, fol-
lowing the increasing order of the oxygen tensions.
Table VIII
1
2
3
4
5
6
7
8
9
10
g
|3
1
u
be
5 «)
3 in <L>
OSS
Composition
3 >,
tfl v
'u
_c
SOJ
c
S 1. rt
of lethal air
Ph
5
V E
.0 'u
Em a
3 0 X
E 3
0 !/>
x° *
O.S E
J c « 0
0 u
3 —
Q 0
.2 u
3>£^
6
C1 c-
|atm.
atm.
h.m.
h.m.
CO*
O*
CXLIII
1.25
32.5
1.5
1 30
1 36
22.1
3.5
27.6
No cranial
suffusions
CXLIV
1.5
69.0
3.3
16.7
28.6
25.1
Red dots on
cranium.
CXLVI
2.5
115.5
5.5
3
53
11.1
33.3
27.7
Cranial
suffusion.
CXL
2.0
117.6
5.6
3
52
13.4
44.4
26.8
"
CXXXIX
1.75
146.3
7.3
2 20
31
11.9
67.8
20.8
CXXXVIII
3.0
258.0
12.1
1 15
10
5.6
78.9
| 16.8
Convulsions,
suffusions.
CXLI
4.0
301.6
14.4
1
7
2.1
71.1
8.4
"
CXXXVII
5.0
415.0
19.7
1 20
6
1.4 | 80.5
7.0
CXLII
8.5
433.5
|20.7
20
2
0.8 | 47.8
6.8
CXLV
5.5
467.5
| 22.3
20
1
1.0 1 82.5
5.5
574 Experiments
If we examine Column 9, we see that the carbonic acid obeys the
law given, up to a pressure corresponding to 5 or 6 atmospheres of
air; but from there on. the product CO., x P decreases rapidly. On
comparing Columns 7 and 9 with Columns 6 and 8 of Table VII,
we find numbers that are quite analogous, and that indicate a simi-
lar intervention of the fatal action of oxygen. It becomes very
evident, when the tension of this gas can be represented by 150,
that is, when it corresponds to an atmosphere and a half of pure
oxygen, or 7 atmospheres of air.
In Figure 7, the lower line C expresses the numbers of Column
9; we see that for the same barometric pressures it remains far
below line B, which represents the results of the experiments in
which ordinary air was used.
Finally, Column 6 shows, as did Column 4 of Table VII, that the
duration of life, referred to a liter of ordinary air under normal
pressure, continues to decrease with astonishing rapidity, when the
pressure, or rather the oxygen tension, increases.
It is therefore overwhelmingly proved that oxygen, under a
certain tension, is a dangerous agent which, in compressed air in
closed vessels, first joins its action to that of the carbonic acid
produced, and which for high tensions is the principal, soon the
only, cause of death; this tension, measured by the expression
O. x P, can be reached, according to the statement already made
so often, by increasing either the barometric pressure P, or the
percentage of 02.
But it is established at the same time that the formula previously
given, The death of sparrows occurs when the tension of the car-
bonic acid, measured as I have specified, is represented by a figure
which oscillates between approximately 24 and 30, expresses the
truth. To prove it experimentally one need only guard against the
excess of oxygen.
F. Compression with ordinary air: elimination of carbonic acid.
The presence of carbonic acid had prevented me, as we have just
seen, from finding the real law which determines the exhaustion of
the oxygen of compressed air for animals allowed to die in closed
vessels.
But the fatal action of compressed oxygen which the studies
just discussed had revealed to me no longer permitted me to think
that the simple law, established for pressures lower than one at-
mosphere, could continue to be applicable to higher pressures.
It was, however, necessary to determine the facts. Apparently
Death in Closed Vessels 575
nothing could be simpler; I needed only to plan the experiments so
that the carbonic acid would be eliminated as it was formed, so
that it could not interfere with the result. But the very low
capacity of the receivers which I had at my disposal made the task
quite difficult, because the bird, as it stirred about, almost always
finally came in contact with the potash, with resultant burns, con-
siderable uneasiness, and often premature death.
I did not get a series of satisfactory results until I used an
apparatus whose receiver is a mercury bottle; it then was easy for
me to perform a large number of experiments, thanks to the
capacity and the wide opening of my receiver. Besides, its great
strength permitted me to carry the compression much higher than
in glass apparatuses. The only inconvenience was the opacity,
which prevented me from following the phases of the experiment
and determining the precise moment of the death of the birds.
I filled a part of the cylinder with water containing potash in
solution. The sparrow, enclosed in a little wire mesh ball, was
suspended above the liquid. Under these conditions, there was
no trace of carbonic acid in the air in which it stayed and died.
I report here a series of experiments that are quite character-
istic.
Experiment CXLVII. September 18. Sparrow at 3Vi atmospheres.
Left in the air in which it died 1 per cent of oxygen.
Oxygen tension: O* x P = 1 x 3.25 = 3.25.
Experiment CXLVIII. September 22. Sparrow at 6V4 atmospheres.
Left 0.8 per cent of oxygen.
0=xP = 5.
Experiment CXLIX. October 3. Sparrow at 9 atmospheres.
Left 2.2 percent of oxygen.
O2 x P = 20.8.
Experiment CL. October 7. Sparrow at 12 atmospheres.
Left 5.6 per cent of oxygen.
OaP = 67.2.
Experiment CLI. January 6. Sparrow at 15 atmospheres.
Left 14.5 per cent of oxygen.
O2 x P = 217.5.
Experiment CL1I. September 30. Sparrow at 20 atmospheres.
Left 18.3 per cent of oxygen.
02 x P = 366.0.
Experiment CLIII. October 1. Sparrow at 24 atmospheres.
Left 20.3 per cent of oxygen.
Os x P = 487.2.
576
Experiments
Table IX
1
2
3
4
c
4)
5
c
>>
O
s
<u
60
Experiment Numbers
3
w
w
01
X
o
_ c
-J? ,
o
k
2°
« 0)
wM
Atm.
||
J a
1-
E-i o
CXLVII
3y4
67.9
1
3.2
CXLVIII
6\k
130.6
0.8
5.0
CXLXIX
9
188.1
2.2
20.8
CL
12
250.8
5.6
67.2
CLI
15
313.5
14.5
217.5
CLII
20
418.0
18.3
366.0
CLIII
24
501.6
20.3
487.2
Line A of the following graph expresses the results of these
last experiments; the oxygen content of the air in which the birds
died is marked on the axis of the y's; the manometric pressures are
K
3ii
■H
■ii
«
MM
—■
Ml
■■1
fc»
mm
Fig. 22 — Confined air which has become lethal under pressures of 20
cent, to 24 atmospheres; oxygen content: A, without carbonic
acid; B, with carbonic acid.
Death in Closed Vessels 577
marked on that of the x's. I added the results already obtained
for pressures lower than one atmosphere.
We see that the exhaustion of the air reaches its maximum at
about 6 atmospheres. At higher pressures, it diminishes rapidly,
so that at 24 atmospheres, the bird dies in an air that is almost pure.
The dangerous action of oxygen is shown very clearly, especially
towards 15 atmospheres.
Line B expresses the results of Columns 7 of Tables V and VII,
that is, the proportion of oxygen remaining in compressed air when
carbonic acid is allowed to act on the experimental bird. We see
that the two curves coincide only at \xk atmospheres; above that,
the acid acts strongly and brings on death in air that is hardly
impoverished.
3. Conclusions.
The conclusions to be drawn from the data reported in the pres-
ent subchapter are more complex than those of the preceding sub-
chapter; the intervention of the carbonic acid and of the oxygen,
for very high pressures, complicate them. We shall therefore make
a distinction:
1. In confined air, at pressures higher than one atmosphere, if
care is taken to eliminate the carbonic acid as it is produced, death
occurs in the same conditions as for pressures lower than one at-
mosphere, that is, when the oxygen tension drops to a determined
value (3.6 on the average for sparrows) .
This is true only up to about 6 atmospheres; beyond that, the
compressed oxygen acts to prevent the exhaustion according to
the formula.
2. When the carbonic acid is not absorbed, it becomes a cause
of death at the moment when its tension rises to a certain value
(from 25 to 28 for sparrows).
This is absolutely exact only on condition of using, for rather
high tensions, air with low oxygen content, so that the oxygen
tension may not rise to the point where it is dangerous to the very
life of the birds.
578 Experiments
Subchapter III
SUMMARY AND CONCLUSIONS
Summarizing, if we clear the principal results from the inci-
dental questions which we have brought up and settled in the
course of our research, the study of death in confined air under
different pressures brings us to the following formulae.
In ordinary air:
A. — At pressures lower than one atmosphere, the death of ani-
mals occurs when the oxygen tension of the air is reduced to a
certain constant value (which for sparrows equals on the average
O, xP = 3.6).
B. — For pressures included between 2 and 9 atmospheres, death
occurs when the carbonic acid tension rises to a certain constant
value (which for sparrows equals on the average CO, x P = 26) .
C. — For very high pressures, death is due exclusively to the too
great tension of the ambient oxygen. It comes quickly when the
tension of this gas reaches 300 or 400.
D. — For pressures of 1 to 2 atmospheres, death seems to be due
especially to the lowering of the oxygen tension, but in part also to
the rise of the C02 tension.
E. — Starting with 3 or 4 atmospheres, the fatal effect of the
oxygen begins to be felt, and becomes very evident at about 9 or
10 atmospheres.
Experiments made either with gaseous mixtures more or less
rich in oxygen, or in the presence of alkalis capable of absorbing
the carbonic acid as it is formed, cause us to give to these laws an
even greater character of generality, and we can formulate them in
the following manner (applying them, for greater clearness, to
sparrows) :
The tension of a gas being represented by the product of its
percentage multiplied by the barometric pressures, we see that
death occurs:
A. — When the oxygen tension drops below 3.6, whether the
barometric pressure is above or below the normal pressure; of
course, in the first case, the carbonic acid must be removed by an
alkali.
B. — When the carbonic acid tension rises above 26, whether the
pressure is above or below the normal pressure; of course, in the
latter case superoxygenated mixtures must be used.
Death in Closed Vessels 579
What we say of carbonic acid is general for all poisonous gases
(CO, HS, etc.) ; only the numerical value of the lethal tension will
change. We shall return to this point when we speak of the
hygiene of workmen in compression tubes.
C.— When the oxygen tension reaches about 300, whatever the
percentage and the pressure are (the latter evidently cannot be
lower than 3 atmospheres, with pure oxygen).
D.— These kinds of death can be combined by twos, A with B
and B with C, according to the pressures and gaseous compositions
used.
Death A is a real asphyxia for lack of oxygen; death B is a poi-
soning by carbonic acid; death C can be called, for convenience and
in spite of the strangeness of the expression, a poisoning by oxygen.
We see— and this is the most general result reached— that in
all cases the barometric pressure in its variations is never directly,
of itself, the cause of the phenomena. It is only one of the condi-
tions which alter the tension of the gases, and the other factor, the
percentage, can completely offset its effects, if its progress is in
the other direction, just as it will increase them rapidly, if its
progress is in the same direction.
If now we leave out the carbonic acid produced, to place our-
selves in conditions nearer those in which our present problem ap-
pears in nature or industry, setting aside certain phenomena which
are quite secondary and to which we shall return at the appropriate
time, we reach these conclusions:
1. That three animals, the first of which exhausts by its respira-
tion a closed space full of air, the second of which is compelled to
breathe in a current of air of diminishing oxygen content, the third
of which is subjected to a gradual decrease of pressure, are all three,
by these different procedures, threatened by the same symptoms
and the same death, a death from lack of oxygen, a real asphyxia;
2. That two animals, one of which breathes in a current of air
of increasing oxygen content while the other is subjected to a
barometric pressure increasing from 1 to 5 atmospheres, are in
identical conditions. That, besides, the animal which breathes pure
oxygen at 2, 3, 4 atmospheres, etc., is in the same conditions as the
one which breathes pure air at 10, 15, 20 atmospheres; both are, by
these different procedures, threatened by the same symptoms and
the same death, a death from excess of oxygen, a poisoning of a
sort hitherto unknown.
All the influence which barometric modifications exercise on
580 Experiments
animals is summed up in these terms: too low an oxygen tension
or too high an oxygen tension.
Such is the very simple explanation given us by experiments in
which we considered the ambient medium much more than the
animal. But this too low or too high tension of the oxygen must
be studied now, not only in its measure, but in its immediate con-
sequences; the animal itself must also be examined with more care.
The first question which I shall now consider is that of the com-
position of the gases contained in the blood of animals subjected
to different pressures.
1 See my Lecons sur la physiologic comparee de la respiration. Lessons XXVII ami
XXVIII, p. 496-526. Paris, 1870.
3 Lecons sur les effets des substances toxiqucs ct medicamentcuses. Paris, 185., p. 125.
3 Lecons sur les substances toxiques, p. 140.
* Lecons sur la physiologie de la respiration, p. 51".
Chapter II
GASES CONTAINED IN THE BLOOD AT DIF-
FERENT BAROMETRIC PRESSURES
Subchapter I
OPERATIVE METHODS AND EXPERIMENTAL
DISCUSSION
I think I should, at the beginning of this chapter, describe the
apparatuses used for the extraction of the gas of the blood, and
indicate with a few details the manner in which I use them. I
shall also place here the account of the control experiments which
I made to study the degree of precision which can be attained by
such researches.
The first of the indispensable instruments is the syringe by
means of which one takes from the blood-vessel a measured quan-
tity of blood to be conveyed to the extraction apparatus.
The model upon which I fixed after many attempts is repre-
sented in Figure 23.
Its body is of thick glass, with ground bore and fittings, for
without this precaution the glass bursts spontaneously at the least
change of temperature. This body is held by and solidly cemented
into two steel end-pieces, fitted with leather gaskets and fastened
to each other by 4 strong rods of steel.
The piston, so arranged as not to turn of itself, is mounted on a
rod equipped with a special screw thread, which in its whole course
makes only one turn and a half. The upper part, closed by a screw,
can be removed and the syringe opened so that the piston can be
completely withdrawn for cleaning. This upper part is pierced
by a small orifice, through which is introduced a little water which
581
582
Experiments
will form a hydraulic seal above the piston. Finally, on one of the
sides, a graduated rule shows the quantity of blood that has been
extracted. At the bottom of the syringe
is screwed in a connecting piece with a
cock, on which can be mounted tubes of
different forms. The total capacity is
from 80 to 100 cubic centimeters.
Such a syringe, which I have described
in detail because it is the model on which
I fixed after many attempts, as being the
simplest, the most convenient, the strong-
est, and the least expensive, holds a
vacuum perfectly. However, through ex-
cess of precaution, I never used it without
introducing water above the piston, and
submerging the whole lower part in water
to a point above the end-piece; not a
bubble of air can then enter.
A cannula being placed in the animal's
artery, part F is connected to it, and when
the serre-fine which closes the artery is
opened, the blood rushes into the syringe
with a pressure sufficient to raise the pis-
ton; I usually take 33 cubic centimeters for
each analysis.
The blood extracted and held in the
syringe is immediately taken to the ap-
paratus for the extraction of gases. The
most important part of this consists of the
mercury pump whose description has been
given above.
To the lateral tube, which I advise
should be placed obliquely, as Figure 24
shows, is fastened, by means of a rubber
tube with thick walls, a large glass tube
about 75 centimeters long, whose lower
extremity fits very tightly in the neck of
a tubular balloon D, whose capacity is
about 1 liter. From the tubulation of
this balloon extends a glass tube of very small caliber, twice bent,
whose end is closed by a cock r.
Fig. 23 — Graduated sy-
ringe for extracting
blood.
Gases of the Blood 583
To obtain a perfect seal in the whole of this apparatus, all the
connections of the different parts are submerged in water, strong
ligatures with rubber bands cut off the air completely, and besides,
a zinc cuff full of water forms a hydraulic seal at the union of the
Fig. 24 — Mercury pump set up for the extraction of blood gases. A. Baro-
metric chamber. B. Movable bulb, communicating with A by
rubber and glass tube. C. Mercury reservoir for collecting the
gases. D. Balloon immersed in warm water, into which the blood
is conducted through cock r, after a vacuum has been made. The
large glass tube leading from D is surrounded by a current of
water which cools the gases and forms a hydraulic seal. R. Three-
way cock which can completely close the barometric chamber
(position 1), or connect A with G (position 2) or A with D
(position 3).
584 Experiments
tube and the balloon. The cock r and the rubber tube on its end
are also submerged.
Through the zinc cuff passes a current of water going upwards
from below, intended to cool the glass tube. This arrangement, the
idea of M. Grehant, has this considerable advantage of stopping
or at least of lessening considerably the coagulable froth which
rises from the blood under the influence of the vacuum, a froth
which may reach the chamber of the pump, mingle with the ex-
tracted gas or at least dirty the whole apparatus.
To make a vacuum in the system described above, I first fit to
the rubber fastened on cock r another tube which connects with
an ordinary pneumatic machine. In this way I shorten the proceed-
ing considerably; the vacuum is next secured perfectly by means
of the mercury pump, according to the method described pre-
viously.
However, one would not secure a perfect vacuum, leaving the
system at the ordinary temperature of the laboratory; I assured
myself of that by very simple experiments, on the details of which
I need not dwell here. Now the presence of a small quantity of
air at the beginning of the experiment may cause difficulties. To
remove it completely, I allow a few cubic centimeters of water to
enter balloon D, by opening cock r; then I warm the balloon until
the bath begins to bubble; at the same time I cut off the current of
cold water which was circulating in the zinc cuff. In this way,
the very hot steam which escapes from the balloon drives out all
the remaining gas, when the pump is operated, and after the fire
is lowered and the current of cold water is allowed to flow, we
have reached a vacuum as perfect as is necessary.
Then after the syringe full of blood is fitted to the rubber tube
of cock r, submerging its lower part in the water and opening the
cock, the suction due to the vacuum forces the blood into balloon
D; then I close the cock and take out the syringe. As a certain
quantity of blood remains in the siphon and as it would be difficult
to exhaust its gases, I plunge the flexible tube into a little dish
full of mercury, and allow the mercury to rise to the point where
the tube curves to enter the balloon.
The blood which has reached the balloon D is subjected there to
the temperature of the bath, which I raised successively from 75°
to 100°. Now I always boil this bath; I am very well satisfied with
the use of this high temperature, and the extraction of the gases
has always been much more rapid and complete than when I
limited myself, as my predecessors did, to keeping the blood at the
Gases of the Blood 585
temperature of the living body, or about that. The only incon-
venience is that the froth is increased by this method; but, thanks
to the length of the communicating tube and the current of cold
water, this froth very rarely enters the pump; furthermore, one can
easily check this froth by the skillful use of the three-way cock;
but these are skillful tricks that cannot be described easily.
Introducing in this way, as I ordinarily did, 33 cc. of blood, the
gases are extracted by three strokes of the pump on the average;
I have seen them all come at the first stroke, and in other cases,
after the third stroke which hardly brings two or three centimeters,
I succeeded in getting one or two more by continuing the operation;
but that is the exception.
I fairly often introduced in advance into balloon D, not merely
a few drops of water, as I said above, but 30 or 40 cubic centimeters
of water, which, of course, I boiled, and from which I extracted all
the gases before introducing the blood. This procedure has the
advantage, by diluting the blood, of lessening its coagulability and
checking the froth which issues from it from persisting and stop-
ping up tube DR, as sometimes happens; but this froth is then
easier to remove by a stroke of the pump, and rises to the top of the
tube; that is why I advised giving the tube a very decided slant
from the cock on, so that the froth may fall back easily instead of
remaining in the angle of the tubes.
I had made a certain number of experiments by this procedure,
and I had assured myself by the comparative method, that it has no
disadvantage from the standpoint of quality and quantity of gases
extracted, when I read with surprise in the Proceedings of the
Academy of Sciences1 a memorandum from MM. Estor and Saint-
Pierre in which the presence of water is charged with causing
enormously important differences in the extractions.
According to the experimenters of Montpellier, the mixture of
water with the blood would facilitate the extraction of the oxygen
so much that the average quantity of this gas would be increased
from 4 cc. to 6 cc. per 100 cc. of blood. If it were so, one should, in
the first place, always use this mixture, and secondly, never com-
pare with each other results obtained with or without water.
Unfortunately, MM. Estor and Saint-Pierre, instead of making
themselves comparative analyses made simultaneously with the
same blood, preferred, following a method which seems to be fa-
miliar to them, to compare to each other analyses made on the
blood of different animals and in entirely different conditions. Just
one of the experiments reported in their memoir (Experiment
586 Experiments
XVI) was made on the same blood, divided into two parts: one,
treated with carbon monoxide, gave 6.66 volumes of oxygen per
100 volumes of blood; the other, added to water and brought to a
boil, released 27.72 volumes. The announcement of these results is
almost enough to prove that both analyses are equally bad.
I might have limited myself to referring the reader to the ex-
periments which I am about to report and in which water has
often been added to the blood without making any change in the
result. But, through excess of scruple, I shall report two experi-
ments which were carried out with great care with the special
purpose of checking the strange statement of the physiologists
of Montpellier.
Experiment CLIV. January 15. Dog of medium size, exhausted by
suppurations resulting from numerous operations.
Drew from the carotid 33 cc. of blood which were immediately
introduced into the pump .... A
Immediately afterward, again drew 33 cc. of blood; but previously
50 cc. of water, from which the gases had been exhausted by vacuum
and by boiling, had been introduced into2 the pump . . . . B
Blood A contained, per 100 volumes, 7.1 of oxygen.
Blood B contained, per 100 volumes, 6.2 of oxygen.
Experiment CLV. January 18. Large dog, intact.
Two pumps for extraction of gases were prepared; into one of
them 33 cc. of water were introduced, then exhausted.
About 70 cc. of blood were drawn from the femoral artery; 33 cc.
were introduced into pump A, 33 cc. into the second B, in which is
the water.
Blood A contains, per 100 volumes, 19.7 of oxygen and 45.0 of CO.
Blood B contains, per 100 volumes, 19.8 of oxygen and 44.2 of CO-.
We see that, whether we are handling a blood extremely low in
oxygen, or a normal blood, the addition of water did not alter at
all the quantity of oxygen extracted from the blood.
Furthermore, the so-called verification of this difference had
as its first purpose an explanation of the strange persistence of
MM. Estor and Saint-Pierres in maintaining that there is, from the
standpoint of oxygen content, a considerable difference between
the blood of the carotid and that of the femoral; an enormous dif-
ference, according to them, since when the blood of the carotid
contains 21.06 volumes of oxygen, that of the femoral would con-
tain only 7.62. They use this difference to support a theory of
their own about the almost instantaneous combustion of the ma-
terials of the blood as it leaves the lung. I should certainly not
have returned to this subject, which I thought I had previously
exhausted, without new communications from MM. Estor and Saint-
Gases of the Blood 587
Pierre. But I must speak of it, since I have happened, in some of
the experiments which are reported below, to compare analyses
of the blood of the carotid with analyses of the blood of the femoral.
I shall therefore repeat here what I have already said else-
where:4 MM. Estor and Saint-Pierre have made no direct com-
parative experiment; if they had made even one, they would have
seen how mistaken their statement is. They have preferred to
search in books, and to compare results obtained by M. Claude
Bernard at different epochs, on dogs placed in the most varied gen-
eral conditions, using carbon monoxide as the means of extracting
the oxygen, with others for which they are indebted to several Ger-
man physiologists who used mercury pumps of different models,
and operated sometimes on dogs, sometimes on sheep. I showed
in detail, in the work quoted above, how truly faulty such a method
is; if one can give the name of "method" to such a procedure. I
might today present the result of my own experiments, made
simultaneously on the same animal and with the same apparatus.
But I prefer to invoke the aid of two experimenters who have
studied these questions with what I consider an exaggerated preci-
sion, but which is a sure guarantee of painstaking in the experi-
ments. Now MM. Mathieu and Urbain,5 investigating whether
there are differences in the blood of the various arteries, reached
the following results, in regard to the carotid and the femoral (page
192):
Carotid— 20.45- 20.99- 15.06- 13.25- 12.75- 18.25- 15.00- 15.75- 14.93
Femoral __ 18.03- 17.69- 13.81- 13.25- 13.50- 18.00- 15.75- 15.75- 14.48
We see, as the authors say correctly, that if there is a slight
difference in favor of the blood of the carotid, it is infinitely less
great than MM. Estor and Saint-Pierre claimed. Let us add that,
according to the experiments of MM. Mathieu and Urbain, the dif-
ference would increase greatly when, instead of taking arteries of
about the same caliber, one examines comparatively the blood of
the carotid and that of an artery of small dimensions, whether it
is close to or far from the heart.. But we cannot dwell on these
data; for our present purpose, it is enough for us to conclude that,
even if it is preferable to take the blood always from the same
artery, there is no serious disadvantage about taking it successively
from the carotid and the femoral, in the same animal, when one
is forced to it.
Furthermore, before expressing ourselves on the importance of
the different causes of errors which may come from physiological
588
Experiments
causes, it is best for us first to get an accurate idea of the exactness
one may hope to secure by using the apparatus which we have
described. Let us consider that the vacuum is made, and that we
are bringing to the cock r the syringe containing, for example,
50 cc. of blood. Let us say first that it is impossible, considering
the caliber of the syringe, to determine this quantity very exactly;
we shall be below the truth in taking as possible errors either
49.8 cc. or 50.2 cc. Furthermore, there will remain in the rubber
tube and the cock r at least 0.5 cc. of blood which will escape
analysis: the truth is then that when we say we
have tested 50 cc, we have really introduced into
the apparatus 49.3 cc. or 49.7 cc. Let us now make
the extraction, and let us suppose it perfectly
complete: at least we have no means of measur-
ing the very small residue which may remain in
the apparatus. We shall obtain on the average
30 cc. of gases which will have to be collected
in two different tubes, if we wish to use narrow
tubes so that the readings may not bring too great
a cause of error. At the same time as the gases,
water vapor has penetrated into the pump and
has condensed; each of our tubes always contains
1 or 2 cubic centimeters of water. How much
carbonic acid in solution has this water absorbed?
We do not know. That is not all; since the gas
is at a high temperature, before measuring it, we
must immerse the tubes completely in little glass
mercury basins, narrow and deep, constructed for
^JBL^ this purpose (Fig. 25); during this time, and
lyij W& under pressure, a new quantity of carbonic acid
.^*™^^^ must enter into solution. Perhaps we can, for
each tube, estimate at 0.2 cc. or 0.3 cc. the total
quantity of this gas of which no account can be
taken.
Now we have two tubes, one of which contains, I suppose, 20 cc,
the other 10 cc; if we refer to what has been said on the possible
errors of analysis by potash and pyrogallic acid, we shall see that
we can vouch for the exactness of the composition only between
limits analogous to the following:
Fig. 25 — Small
mercury reser-
voir.
Gases of the Blood 589
First tube
Second tube
cc.
cc.
Carbonic acid
12
1
11.9
6.9
Oxygen
6.9
2.5
7
2.6
Which, following the combinations, may give us the following
extreme total results:
Carbonic acid __. 19 or 18.8
Oxygen 9.6 or 9.4
Let us add to this the quantity of carbonic acid contained in
the condensed water, and the direct measure may give us a result
for this gas which is below the truth, from 0.4 cc. to 0.6 cc.
We must now double all these figures, to get the total quantity
of gas contained in 100 cc. of blood, the amount which is commonly
used; so that, in spite of the greatest precautions, and supposing
that the extraction of the gases has been perfect, it is impossible
to say that the number obtained is not too high or too low for the
oxygen and the nitrogen by 2 or 3 tenths, and for the carbonic
acid by nearly a unit.
After that we can judge the value of these second and third
decimals, which the tables of analyses almost always display fol-
lowing their whole numbers. I am strongly inclined towards this
truth that, if the decimals are exact from the arithmetical point of
view, the number of units itself is false from the chemical point of
view, for to the different causes of error mentioned above, we
should add the imperfection of the apparatuses which most of the
operators use.
And what is to be said now from the physiological point of view?
The analysis of which we have just spoken gives us, for a deter-
mined case, an absolute result, error excepted. But how many
things cause complications, if we wish to compare it to another
analysis made by the same experimenter, with the same instru-
ment, on another animal belonging however to the same species! I
have specified before0 the differences which, from the point of view
of the oxygen content, may be presented by the blood of an animal
placed in different conditions, as in digestion and fasting, etc. Since
then, MM. Mathieu and Urbain, repeating with the gas pump the
experiments which I had performed simply with carbon monoxide,
and which, consequently, applied only to oxygen, have multiplied
and varied the conditions in which the animals can be placed.
590 Experiments
Their work, which develops, confirms, or rectifies my former at-
tempts, has shown that the absolute and relative proportion of the
gases of the blood is subject to numerous variations.
But I limit myself for the moment to the study of those varia-
tions that may be important in the subject with which I am con-
cerned at present.
Now we are considering here experiments made in the lapse of
two or three hours at most. The only influences which can act in
this case are: (1) the former bleedings; (2) the animal's respiratory
rate; (3) its state of repose or agitation.
MM. Mathieu and Urbain (loc. cit., page 14 et seq.) attach
much importance to the former bleedings. According to them, if
20 cc. of arterial blood are extracted from a dog, in a second bleed-
ing of 20 cc. there will be considerably less oxygen and carbonic
acid; successive bleedings would increase these differences. On the
average, for bleedings of 20 cc. made at intervals of an hour and
a half, we should have total diminutions of 1.25 cc; 2.25 cc; 3.00 cc;
3.50 cc; 3.75 cc After a bleeding of 60 cc, the difference would be
on the average 2.50 cc, and after a bleeding of 150 cc, 3.91 cc
According to them, these modifications would be due principally
to the diminution in vascular tension; in fact, they would not be
noted if after the first bleeding a quantity of water equal to the
quantity of blood removed were injected into the vessels.
The carbonic acid would vary under the influence of successive
bleedings in the same direction and following a higher proportion
than the oxygen.
As for me, I have never noticed such considerable differences
in the gaseous content of blood drawn repeatedly from the vessels.
Often the numbers obtained remained absolutely identical, when
the animal was at rest. This happened, for example, in the follow-
ing experiment.
Experiment CLVI. July 18. Large shepherd dog.
At 2 o'clock, drew 44 cc. of blood from the femoral; animal per-
fectly quiet .... A
Drew next 43 cc. of blood from the same artery . . . . B
At 3:30, drew 42.5 cc. from the same artery . . . . C
Blood A contains per 100 volumes: O2 21.4; CO 39.5.
Blood B contains per 100 volumes: O 21.2; CO 40.1.
Blood C contains per 100 volumes: O2 21.5; CO 38.6.
The numerous experiments which will be reported in the present
chapter show frequently that successive bleedings do not give such
unlike results as one might think from the conclusions of MM.
Urbain and Mathieu.
Gases of the Blood 591
To study the influence of the number of respirations by isolating
it from that of the general movements of the body, which is always
involved, I poisoned the animals by curare, and when they were
completely paralyzed, I made use of artificial respiration by means
of a bellows introduced into the trachea.
This bellows (Fig. 26) has an intake valve A, furnished with a
tube permitting any gas to be pumped into the lungs, and with a
graduated guide bar provided with a slide to control the move-
ments of the bellows. The variable position of the slide determines
the quantity of air injected. With this instrument, nothing is
easier than to measure exactly the amplitude and the number of
Fig. 26 — Bellows for artificial respiration (A, pipe with valve which per-
mits the use of any gas).
the artificial respirations. When the cannula has been introduced
into the trachea, which it does not quite fill, the little space left
between it and the walls is sufficient for the expiration to be made
easily; besides, in this respect conditions are always identical.
I also used the apparatus construed according to the specifica-
tions of M. Grehant, which in my laboratory is operated by a small
water motor.
Here is the result of an experiment, taken as an example.
Experiment CLVII. February 19. Dog weighing 18 kilograms.
At 4:05, lethal dose of curare subcutaneously; falls at 4:25; trachea
opened and artificial respiration carried on, the bellows delivering
350 cc.
At 4:40, the artificial respiration is fixed at 16 per minute; the
pulse is 90. At 4:50, 72 cc. of blood taken from the femoral
artery ... A
592 Experiments
Immediately after, respiration increased to 70 per minute; the
pulse rises to 140; the rectal temperature is 38.5°. At the end of 10
minutes, 72 cc. of blood taken from the same artery . . . B
The pipe of the bellows is fitted to a bag of carbonic acid; after
15 minutes of artificial respiration, the heart stops. 55 cc. of blood
immediately taken from the left heart by a cannula inserted through
the left carotid . . . . C
The rectal temperature is then 36°.
Blood A contains per 100 volumes: O 19.7; CO 36.7.
Blood B contains per 100 volumes: Os 20.7; CO 30.1.
Blood C contains per 100 volumes: Oa 5.2; CO2 90.2.
We see that the rapidity of the respiratory movements, or more
generally, that the passage through the lungs of a greater quantity
of air in a given time has a double result: an increase in the pro-
portion of the oxygen of the blood, and a decrease in the propor-
tion of carbonic acid, the increase of the oxygen being much less
than the decrease of the carbonic acid.
In order to study the influence of the state of repose or of the
muscular contractions of the animal, and to isolate it from all cir-
cumstances of another sort, I killed a dog by section of the medulla,
and then carried on artificial respiration in a regular manner. At
the end of some time, the animal being naturally in complete im-
mobility, I drew blood; then, by means of a strong induced current
passing through the body from the mouth to the anus, I obtained
general energetic movements that were more or less numerous,
after which I drew blood again.
Here are the results of an experiment carried on in. this way.
Experiment CLVIII. November 12. Strong dog weighing 15 kilo-
grams. Medulla cut; artificial respiration fixed at 15 per minute for
5 minutes. Then drew 25 cc. of blood from the carotid ... A
Spinal cord then excited from medulla to anus by strong induced
currents which cause general convulsions, especially in the posterior
members. Artificial respiration is continued in the same rhythm.
After 5 minutes of excitation, 25 cc. of carotid blood drawn . . . B
Blood A contains per 100 volumes: Oj 26.6; CO^ 31.2.
Blood B contains per 100 volumes: Oa 18.2; CO* 28.8.
But we must realize that in the ordinary and natural state of
things the two phenomena which we have artificially separated
are combined, mingle, and superadd their effects, which then coun-
terbalance each other. In the vast majority of cases, indeed, an
animal which struggles breathes more frequently and deeply, and,
conversely, repose accompanies a calmer and slower respiration.
Gases of the Blood 593
Experiment CLIX. January 24. Large hunting dog. Left femoral.
75 cc. of blood taken; the analysis was lost by accident.
74 cc. then taken; the animal, which had been tied down for a long
time, had been perfectly quiet (A) ; at the end of an hour, the ani-
mal excited struggled violently, howling loudly, for some minutes,
after which 76 cc. of blood were taken (B).
Blood A contains per 100 volumes: O* 18.6; CO* 37.0.
Blood B contains per 100 volumes: O* 19.4; CO 35.2.
Experiment CLX. March 5. Small dog, whose laryngeal recurrents
were cut March 1, but in good shape. Femoral artery.
The animal being very calm, 40 cc. of blood were drawn (A) ;
then the dog is made uneasy by placing a little ammonia under its
nose, and the same quantity of blood was drawn (B).
Blood A contains per 100 volumes: O* 11.7; CO 33.6.
Blood B contains per 100 volumes: O 12.4; CO* 32.7.
The dog was then poisoned by curare; the excitation of a sciatic
nerve made the blood pressure rise 2 cm., to 4 cm., even after the
section of the two pneumogastrics. The peripheral end of these no
longer acting on the heart, the central end, when excited, increased
the blood pressure. After having cut transversely the right half of
the lumbar cord, an increase of pressure was obtained by excitation
of the right sciatic; the left gave a doubtful result.
Here are two experiments that indicate that in most cases one
does not need to give much consideration to any modifications in
the behavior of the animal at different moments of the experiment.
The comparative analyses show that for oxygen the causes of error
hardly reach unity, and that for the carbonic acid they hardly
exceed two units.
But in certain exceptional circumstances, the differences may
reach values that are much higher. That happens sometimes, for
example, when the trachea of an animal is opened and a cannula
is inserted. All physiologists have noticed that in these conditions
the animals are often seized by an extraordinary panting, which
usually ceases at the end of a few minutes. Now if blood is drawn
during this period, we find that its gaseous composition is very dif-
ferent from what it was before.
I shall offer as examples the two following cases, the most re-
markable I have found.
Experiment CLXI. December 20. Vigorous dog, weighing 16.5
kilos.
At 3:55, I drew from the carotid 33 cc. of blood, which is quite
dark .... A.
At 4 o'clock, I placed a tube in the trachea; the respirations
became extremely rapid for 5 minutes; then calm returned and shortly
after, a new acceleration, which ended at 4: 10, the very moment when
594 Experiments
33 cc. more of blood was being drawn, which was evidently not so
dark . . . . B
Blood A contains per 100 volumes: O 15.1; CO 40.8.
Blood B contains per 100 volumes: 0 20.3; CO 24.0.
Experiment CLXII. January 24. Bulldog.
At 2:30, I extracted 32 cc. of blood from the carotid, the animal
breathing through the natural channels ... A
I opened the trachea to place a tube in it; the respirations became
extraordinarily hasty; at the end of 5 to 6 minutes of this rhythm, I
took 33 cc. of blood, considerably redder . . . . B
Blood A contains per 100 volumes: O, 16.0; CO, 41.5.
Blood B contains per 100 volumes: O 23.4; CO 15.2.
But, I repeat, this is an extreme; nothing quite comparable ap-
peared in animals breathing through natural channels. A great
number of experiments permit me to state that the circumstances
depending upon the animal's behavior, although not negligible, are
not such as to forbid the drawing of conclusions. Of course, I could
not always prevent interference from them, but when it was very
manifest, I abandoned the experiment.
Finally, without dwelling on the differences which may appear
in the blood of a dog, depending on whether the animal is fasting
or digesting such and such kinds of food, I shall say that all of my
dogs had eaten food with very little meat about eight o'clock in
the morning; the experiments were generally performed from two
to six o'clock.
We see that definitely the sources of error contained in our
analyses, which have both chemical and physiological causes, are
about one unit for oxygen and three or four units for carbonic
acid. I maintain that in practice one cannot attempt to obtain
greater accuracy than this without mistaking a systematic error
for the truth.
Subchapter II
GASES OF THE BLOOD UNDER PRESSURES
OF LESS THAN ONE ATMOSPHERE
1. Experimental Set-up.
Extraction of blood from the vessels of an animal subjected to
the influence of diminished pressure was not an easy problem.
The apparatus at my disposal, which I used in my researches in
diminished pressure, is composed of two vast cylindrical chambers
(Fig. 27) which can be isolated from each other by a communicat-
ing door. These chambers are 2 meters high and 1 meter in
Gases of the Blood
595
diameter, which gives them a capacity of about 1.550 cubic meters:
I say "about" because of the convex dome which tops them. They
are suitably lighted by glass portholes as seen in the figure. The
doors opening outward and resting on rubber gaskets close quite
tightly, atmospheric pressure tending to fit them more closely to
the gaskets as the pressure within diminishes. An exterior
manometer, a sort of barometric tube whose chamber communicates
Fig. 27 — Large apparatus for the study of low pressures. A. A'. Cylinders
of riveted sheetiron, with glass portholes. B. Cylinder in which
the pressure can previously be lowered to 5 centimeters, so as to
obtain a rapid decompression in the large cylinders. C. Large
glass bell-jar in which an instantaneous decompression can be
made by using cylinder B. R. R'. Cocks which communicate each
with one of the cylinders A and A', which are separated by an
inner door, shown by the dotted line. p. Communication cock for
C; r, r', d, d'; s, s', s", openings and cocks for taking air samples,
extracting blood, etc. a, a'. Thermometers, m, m'. Manometers.
with one of the two large reservoirs, indicates immediately the
amount of the inner decompression; thermometers pass through
the wall.
The pressure is diminished by a pump moved, in the beginning,
by a little steam engine, as the figure shows. I replaced it by a
gas motor of the Lenoir system, a machine much easier to handle
in a laboratory, and better adapted to tasks which one must under-
take and leave according to circumstances over which one has no
control.
596
Experiments
I can thus diminish the pressure 20 centimeters in 5 minutes,
40 centimeters in 10 minutes. I can get a pressure of 25 centimeters
easily enough in 20 minutes; but I have had the greatest difficulty
in going below this figure, and could not get below 17 centimeters.
We see in the figure an independent cylinder B. I used it as a
vacuum reservoir, if I may use this term, in certain experiments.
Finally, the tube, which in the figure communicates with a glass
bell-jar C, is the one which I later fitted to the table with pneumatic
plates represented in Figure 15.
Fig. 28 — Dog prepared to be placed in the cylinders of Figure 27 and to
serve for the extraction of blood under diminished pressure.
The extraction of the blood of a dog placed in such an apparatus
is a rather difficult enterprise.
The animal is first securely attached on its back, as shown in
Figure 28, to the uprights of a sort of cage of solid wood, curved
so as to conform exactly on its convex edge to the concavity of
the cylinder, and capable of being fastened to it by holes which fit
over the hooks of strong staples screwed to the sides of this cylin-
der. The head of the animal is held in a sort of movable muzzle,
which allows the neck to be extended according to the require-
Gases of the Blood 597
ments of the experiment and to be held completely motionless. The
front feet are fastened to the bars of this cage, and for the hind
feet, two bars mounted in grooves in an arc can be separated more
or less according to the size of the animal.
In this position one can draw blood either from one of the
carotid arteries or from one of the femorals. The carotids are more
convenient on account of both their size and their nearness to the
wall of the cylinder, and I almost always used them.
This wall, opposite the place where the artery has been exposed,
is pierced by several holes, like the head of a watering-pot; through
one of these holes is passed the cannula used to extract blood; the
other holes are closed by a handful of modeling wax firmly pressed
over them.
And now how to extract the blood? In the artery it is subjected
to a pressure equivalent to about 15 to 18 centimeters of mercury,
which makes extraction very easy when the operation takes place
in normal pressure. But the animal is placed in an apparatus in
which the pressure is to be diminished and we are to expose the
artery to the outside air. It is quite evident that when the pressure
is lowered 15 to 18 centimeters, the blood will no longer have any
tendency to flow from the vessel, and that when the pressure is
carried still lower, the outside air will tend to rush into the ani-
mal's artery and from there to spread through the whole circulatory
system.
There is the danger and there lies the difficulty. To avert the
one and solve the other, I used (Fig. 29) first a cannula A forked
at its free extremity, into which slipped a stylet ending in an olive.
The latter was arranged so that it could exactly cover the orifice of
the cannula when it was placed in the animal's artery. When I
wished to extract blood, I pulled the stylet until the olive reached
the fork. All this time the cavity of the cannula was completely
closed, the stylet sliding tightly in a pierced rubber stopper which
a head a fastened closely. Then, by fitting the syringe in Figure 23
to the orifice a' by means of a rubber tube with thick walls, and by
opening the cock, blood could be extracted without danger.
But in spite of all the precautions taken, I have had difficulties
resulting from the entrance of a certain quantity of air. Indeed,
a microscopic orifice is enough to let bubbles enter, and these,
reaching the left heart and being pumped thence into the arteries,
can, as you will see, cause very serious troubles. Sometimes the
quantity of air admitted thus was even enough to bring on imme-
diate death.
598
Experiments
I then had another cannula made, all of metal, formed of two
pieces joined at b, of which Figure B gives a sufficient idea. I still
had difficulties, and finally developed an arrangement pictured in
Fig. 29 — Different forms of cannulae A, B, C, and of serres-fines D, E,
for extracting blood under decreased pressure.
C which gave me excellent results, and which, as often happens,
is the simplest of all.
The experiment is performed in the following manner: After
the animal's carotid has been exposed and litigated at its upper
extremity, I hook upon the walls of one of .the compartments of the
Gases of the Blood
599
apparatus the framework which holds the dog. The operator enters
the cylinder at the same time, and passes through one of the holes,
with which the wall is riddled at that point like the head of a
watering-pot, the serre-fine D, whose long handle d remains out-
Fig. 30 — Extraction of blood from an animal under decreased pressure: A
artery; P wall of the apparatus; S serre-fine; a cannula placed in
the artery; s syringe extracting the blood (its lower armature
must be entirely immersed in water).
side. Then spreading apart the two jaws of the serre-fine, so as to
make the little guide-rods leave their holes, he brings the carotid
in to the space d," from which it cannot slip, thanks to the bolts;
the movable lever d, controlled from the outside by the handle d,
permits him to compress the artery as low as possible. He then
opens the artery, and inserts in it the metal cannula, the end of
600 Experiments
which he passes through one of the holes in the wall. Next the
rubber tubing and the cock are fastened on.
The cylinders having been closed and the decompression
reached, when one wishes to draw blood, he arranges things as
shown in Figure 30. The serre-fine is opened, the syringe whose
piston is covered by a layer of water is applied, and suction is made.
Since all the connections are immersed in water, no accidents can
happen.
But after the extraction, there remains in the cannula a long
clot which generally prevents a new extraction. It was to avoid
this difficulty that I devised the stylet of the cannula A, which
drove blood back into the animal; only, as I said, I could not be sure
of complete closing. I must add that when the extractions were
not too far apart, I could sometimes suck out by the syringe the
clot which was still diffluent. At other times, immediately after
drawing blood, I injected into the cannula a little sodium carbonate
solution, to prevent coagulation.
I drew out thus, as I said, each time, from 30 to 40 cc. of blood.
I waited until the decompression had been maintained for several
minutes before making the extraction. The blood at normal pres-
sure was sometimes taken in advance; but the tendency towards
coagulation, which resulted from this practice, caused me usually
to take it afterwards. I then took care to wait rather a long time.
The account of experiments carried on thus will indicate these
details.
2. Experiments.
Experiment CLXIII. June 22. Pressure 76.4 cm.; temperature 23' .
Large dog, which had been operated on several times the day before:
does not seem sick.
Drew from the femoral artery 46 cc. of blood, at normal pressure;
blood quite red .... A
Placed in the large apparatus; brought down 45 cm., in a half hour;
real pressure 31.4 cm.; after 10 minutes, drew from the carotid 46.5 cc.
of blood; blood considerably less red . . . . B
Blood A (76.4 cm.) contains per 100 volumes: O 18.8; CO. 39.7.
Blood B (31.4 cm.) contains per 100 volumes: O 12.0; CO. 31.0.
Therefore at a pressure of 31.4 cm., there has disappeared 36.2
per cent of the oxygen existing at normal pressure, and 21.9 per cent
of the carbonic acid.
Experiment CLXIV. June 24. Pressure 76 cm., temperature 21°.
Large dog.
Normal pressure: drew from the femoral artery 46 cc. of blood,
very red .... A
Pressure lowered 54 cm., in about three quarters of an hour (real
Gases of the Blood 601
pressure 22 cm.). Drew from the same artery 40 cc. of blood, very
dark . . . . B
Blood A (76 cm.) contains per 100 volumes: O 21.5; CO 41.9.
Blood B (22 cm.) contains per 100 volumes: O 10.7; CO 22.0.
50 per cent of the oxygen has disappeared and 47.5 per cent of
the original carbonic acid.
Experiment CLXV. June 28. Pressure 76 cm.; temperature 21.8°.
Dog of the preceding experiment, quite recovered, vigorous.
While ligating the left carotid in preparation, the femoral ligated
three days before opens, and blood issues; the animal thus loses about
50 cc. of blood.
Then put into the apparatus, pressure is lowered 19 cm. in 5
minutes (real pressure 57 cm.); left there for a half hour. Then 42.3
cc. of blood drawn from the left carotid, not very red .... A
The animal, brought back to normal pressure, breathes quietly
for an hour. Then 42.3 cc. of blood drawn from the same carotid;
evidently redder . . . . B
Blood A (57 cm.) contains per 100 volumes: O 18.6; CO^ 35.4.
Blood B (76 cm.) contains per 100 volumes: 0^> 21.6; CO 36.3.
Experiment CLXVI. July 4. Pressure 76 cm.; temperature 22°.
Female dog of moderate size.
At 3 o'clock, 45.3 cc. of blood, not very red, drawn from a
femoral .... A
Animal put into apparatus; howls and is very uneasy; pressure
lowered 52 cm.; then 47 cm.; then 50 cm.; all in about a quarter of an
hour. The real pressure is 26 cm. 43.1 cc. of very dark blood then
drawn from the same artery . . . . B
Blood A (76 cm.) contains per 100 volumes: O 18.3; CO 32.8.
Blood B (26 cm.) contains per 100 volumes: O^ 9.8; CO 24.5.
Experiment CLXVII. July 6. Pressure 76 cm.; temperature 24.5°.
Dog of the preceding experiment, in good condition.
Put into the large apparatus; in a quarter of an hour brought to
44 cm. of actual pressure; very uneasy; kept at this pressure for 20
minutes, and then 32.6 cc. of rather dark blood drawn from the left
carotid .... A
The animal having been brought back to normal pressure, which
took about 5 minutes, 42.3 cc. of blood, evidently redder, were drawn
from the left carotid immediately . . . . B
Blood A (44 cm.) contains per 100 volumes: O 16.3; CO 23.3.
Blood B (76 cm.) contains per 100 volumes: O* 19.8; CO 29.1.
Experiment CLXVIII. July 8. Pressure 75.9 cm.; temperature 25°.
Very large dog.
Put into the apparatus; has a new cannula of Model A (Fig. 29) in
the left carotid. Pressure lowered 20 cm. in a quarter of an hour, and
left there a quarter of an hour. 39 cc. of blood then drawn with
difficulty .... A
Pressure lowered 30 cm., and an attempt is made to extract blood;
but it is impossible, the cannula is twisted.
602 Experiments
Brought back to normal pressure, the dog continues to howl and
breathe very quickly and very noisily, as it has done since blood A
was extracted. 48 cc. of very red blood then extracted . . . . B
The animal when untied, cannot walk; it is not paralyzed in any
limb, and yet cannot stand up on all-fours.
Next day, same condition, except that the respiration is easy.
It dies at the end of several days, having remained drowsy and
unable to walk. In the autopsy a gray cerebral softening is found.
Evidently bubbles had entered the circulatory system, some of which
penetrated the nervous centers and cut off the circulation.
Blood A (56 cm.) contains per 100 volumes: O 20.9; CO 35.3
Blood B (76 cm.) contains per 100 volumes: Ch 26.4; CO* 22.7
I shall not include in the general discussion of the experiments
the preceding curious result; but I thought I should not omit it.
I call the reader's attention to the localized cerebral softening due
to the penetration of the air.
Experiment CLXIX. April 30. Pressure 77 cm.; temperature 16°.
Dog weighing 11.5 k.
At 4:25, put into the apparatus, and brought in 10 minutes to 36
cm. of actual pressure. At 4:45, 46 cc. of very dark blood drawn from
the right carotid .... A
5 o'clock. Returned to normal pressure; at 5:05, 46 cc. of very red
blood drawn . . . . B
Blood A (36 cm.) contains per 100 volumes: O 11.9; CO* 25.2
Blood B (77 cm.) contains per 100 volumes: O 20.6; CO 39.0.
Experiment CLXX. May 1. Pressure 76 cm.; temperature 16°.
Dog of preceding experiment, quite recovered.
4:15. 41 cc. drawn from left carotid; respiratory rate 60 .... A
4:30. Put into the large receiver; at 4:45, pressure lowered 33 cm.,
air admitted to 30 cm. (pressure 46 cm.). At 4:45, 38 cc. of blood
drawn . . . . B
Brought to 56 cm. of actual pressure; at 5:15, respiratory rate 100;
41 cc. of blood drawn . . . . C
Brought slowly to normal pressure; at 6:20, respiratory rate 60;
41 cc. of blood drawn . . . . D
Blood A (76 cm.) contains per 100 volumes: O 21.9; CO^ 34.7.
Blood B (46 cm.) contains per 100 volumes: O 20.3; CO 30.5.
Blood C (56 cm.) contains per 100 volumes: O 21.1; CO 34.7.
Blood D (76 cm.) contains per 100 volumes: O 21.1; CO 35.2.
The average between A and D is: O^ 21.5; CO 34.9.
Experiment CLXXI. May 3. Pressure 76 cm. Young dog, very
lively, weighing 4 k. Right carotid.
4:32. Put into the receiver; at 4:45, lowered 45 cm., respiratory
rate 24, divided into periods of 3 or 4 medium and 1 very deep; then
rest.
4:58. The decompression has varied between 44 cm. and 47 cm.;
at present it is 45 cm.; 31 cm. of actual pressure. 41 cc. of blood drawn,
darker than ordinary venous blood .... A
Gases of the Blood 603
Brought slowly to normal pressure.
At 5:07, at 25 cm.; 16 respirations of the same type. At 5:13,
normal pressure; 41 cc. of blood drawn, lost; at 6:20, 16 respirations,
same type; 41 cc. of blood of ordinary color drawn . . . . B
Blood A (31 cm.) contains per 100 volumes: O 13.6; CO* 36.5
Blood B (76 cm.) contains per 100 volumes: O 19.4; CO 48.4
Experiment CLXXII. May 7; pressure 75 cm.; temperature 18°.
Female dog weighing 11 k.
3:12. Put into receiver; at 3:25 lowered 40 cm.
3:45, a decrease of 39 cm. (36 cm. of actual pressure); 21 to 24
respirations; 41 cc. of very dark blood drawn .... A
3:50. Brought to 46 cm. pressure and maintained there. At 4:05,
41 cc. of blood, not so dark, drawn; 18 to 21 respirations . . . . B
Brought to normal pressure, at 4:15; at 4:35, 30 respirations; at 5
o'clock, 41 cc. of not very red blood drawn . . . . C
This dog, before blood was drawn, and after she was untied,
developed strange tonic and clonic convulsions, with corneal lack of
sensitivity and howls; the second attack was very severe, lasted 15
minutes at least, and was followed by a state of stupor, with little
plaintive cries; hysteria? epilepsy?
Blood A (36 cm.) contains per 100 volumes: O- 8.9; CO 34.3.
Blood B (46 cm.) contains per 100 volumes: O 13.2; CO 40.7
Blood C (76 cm.) contains per 100 volumes: O 20.1; CO 41.1
Experiment CLXXIII. May 8. Pressure 75.5 cm.; temperature 17°.
Little dog, weighing 5 k.
At 4 o'clock, 33 cc. of very red blood drawn from the right carotid
. . . . A
At 4:28, put into the receiver. At 4:35, pressure dropped 34 cm.;
13 respirations, deep; at 4:50, pressure dropped 50 cm.; 20 respirations,
shallower. At 5:05, pressure still at a diminution of 50 cm.; 18 respi-
rations; 35 cc. of very dark blood drawn . . . . B
Blood A (75.5 cm.) contains per 100 volumes: O 22.6; CO 39.7.
Blood B (25.5 cm.) contains per 100 volumes: O 9.8; CO? 23.1
Experiment CLXXIV. May 9. Pressure 75.5 cm.; temperature
16.5°. Dog of Experiment CLXXI, still somewhat sick. Left carotid.
At 3:30, drew 27.5 cc. of blood .... A
At 3:50, put into receiver; at 4:03, the pressure is at 36 cm.; at
4:18, the same; 33 respirations, medium. Drew 41 cc. of very dark
blood . . . . B
Blood A (75.5 cm.) contains per 100 volumes: O, 13.3; CO= 34.9.
Blood B (36 cm.) contains per 100 volumes: O 8.5; CO 21.4.
Experiment CLXXV. May 15. Pressure 76 cm.; temperature 17°.
Fat and strong female dog, which had eaten at noon.
At 3:10, drew 34.5 cc. of blood from the right carotid; animal
quiet .... A
At 3:20, put into the apparatus, howls, is uneasy; at 3:25, pressure
is 56 cm. At 3:35, pressure maintained; drew 34.5 cc. of blood, animal
quiet, 30 respirations; but has been very uneasy . . . . B
604 Experiments
At 3:40, pressure lowered 30 cm.; at 3:55, the same; drew 34.5
cc. of blood; animal quiet, but had been uneasy . . . . C
At 4 o'clock, pressure lowered 40 cm.; animal in the same condi-
tion; drew 34.5 cc. of dark blood . . . . D
Blood A (76 cm.) contains per 100 volumes: O^ 17.4; CO 33.8
Blood B (56 cm.) contains per 100 volumes: O 15.5; CO 28.0
Blood C (46 cm.) contains per 100 volumes: O 12.5; CO2 26.4
Blood D (36 cm.) contains per 100 volumes: O2 10.8; CO 22.8
Experiment CLXXVI. May 22. Pressure 76 cm. Medium-sized dog,
which had eaten at noon. Right carotid.
At normal pressure, 13 respirations.
3:35. Put into apparatus.
4:05, pressure lowered 40 cm., maintained.
4:07, 15 respirations, somewhat irregular.
4:25, the same; drew 33.3 cc. of blood, very dark .... A
4:33, air admitted; pressure lowered 20 cm.
4: 50, drew 33.3 cc. of blood, redder than A .... B
4:55, normal pressure.
5:25, drew 33.3 cc. of blood, quite red .... C
Blood A (36 cm.) contains per 100 volumes: 0^ 9.6; CO 33.9
Blood B (56 cm.) contains per 100 volumes: O 12.4; CO 35.0
Blood C (76 cm.) contains per 100 volumes: O 16.9; CO 45.7
Experiment CLXXVII. June 21. Female dog of average size, never
having been used before. Cannula in the right carotid artery.
4:15, decompression begun.
4:45, decompression of 54 cm.; great uneasiness from the begin-
ning.
5:15; 56.5 cm.; 120 respirations.
5:30; 57.5 cm.; I draw 50 cc. of blood, very dark A.
Air admitted until the decompression is only 36 cm., then the
decompression is resumed.
6:08, pressure down 50 cm.; I draw 35 cc. of blood, very dark. . B
6:20, 56 cm.; 40 cc. of blood, also very dark . . . . C
6:20, air admitted; normal pressure restored at 6:55.
7: 10, drew 57 cc. of blood, quite red . . . . D
Blood A (19 cm.) contains per 100 volumes: O 4.9
Blood B (26 cm.) contains per 100 volumes: O 6.5
Blood C (21 cm.) contains per 100 volumes: O 4.5
Blood D (76 cm.) contains per 100 volumes: 0= 14.8; CO 22.1
Experiment CLXXVIII. July 3. Dog which has never been used,
weighing 11 k.
2:30, I draw from the right carotid 35 cc. of blood moderately red;
the animal howls and struggles .... A
2:40, decompression begins.
3 o'clock, decompression of 55 cm.
3: 11, decompression of 57 cm.; drew 35 cc. of blood, very dark . . B
Admitted air.
Blood A (76.5 cm.) contains per 100 volumes: 19.2 of oxygen.
Blood B (19.5 cm.) contains per 100 volumes: 4.2 of oxygen.
Gases of the Blood 605
Experiment CLXXIX. July 5. 76.5 cm. Dog weighing 10 k.
Drew from the right carotid 35 cc. of very red blood; 38 respir-
ations, with little howls .... A
3:25, put into the apparatus.
3:45, pressure 30.5 cm., struggles, howls. At 3:55, pressure 24.5;
the gas machine stops.
4:05, pressure 38 cm.; machine started again; 26 respirations, quiet.
4:12, 26.5 cm.; 60 respirations, interrupted by hiccoughs; at 4:26,
19.5 cm.; 74 respirations, also with hiccoughs.
4:30, pressure 18 cm.; drew 35 cc. of very dark blood . . . B
4:42, pressure 17 cm.; 80 respirations; drew 35 cc. of very dark
blood . . . . C
Opened the cock; at 4:55, the pressure had risen to 26 cm.; it was
maintained there, and at 5: 10, 35 cc. of dark blood drawn . . . D
5:13, returned to normal pressure.
6:00, took 35 cc. of blood, very red . . . E
Blood A (76 cm.) contains per 100 volumes: O. 20.8; CO* 46.1
Blood B (18 cm.) contains per 100 volumes: O 7.6; CO 12.9
Blood C (17 cm.) contains per 100 volumes: Ch- 7.1; CO2 11.9
Blood D (26 cm.) contains per 100 volumes: O. 9.2; CO. 13.7
Blood E (76 cm.) contains per 100 volumes: O? 20.8; CO. 40.5
When, after having followed the preceding experiments, we
examine Table X, which summarizes them and in which they are
arranged in the order of decompression, one of the first facts to
attract our attention is the remarkable variation presented by the
figures in Columns 3 and 4, which express the quantities of oxygen
and carbonic acid gas contained at normal pressure in 100 cc. of
blood. The variations for oxygen (setting aside Experiment
CLXXIV for reasons which I shall specify shortly) were from 16.9
to 22.6; those of carbonic acid, from 29.1 to 48.4. I should note that
there is no proportion, either direct or inverse, between the in-
creases or diminutions of these two gases, so that the variations of
the total (Col. 5) , which were from 48.2 to 67.8, are not the expres-
sion of any distinct law.
The explanation of these variations cannot be found in the
details of the experiments. All my dogs were in good health, fed
on the same diet and at the same length of time before the experi-
ment; I took care, as I said, to draw blood from them during a quiet
period: they were, in short, as similar as possible. I am therefore
led to believe that these results agree with the true state of things
and that there are important differences between individuals in the
oxygen content of the arterial blood, although all circumstances
are similar. Furthermore, these variations are quite as apparent
in the tables of analyses published by other authors; it would be
a real delusion to get rid of them by getting some sort of an average.
606
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Gases of the Blood 607
In my experiments, just one of the differences observed is ex-
plained by the state of the animal, in Experiment CLXXIV. Here
we were handling a small dog (4 k.) , from which five days before
I had drawn 110 cc. of arterial blood, that is, about half of the
amount the loss of which would have killed it immediately, and
which had remained sick and without appetite ever since. In the
first experiment, its blood had given 19.4 per cent of oxygen and
48.4 of carbonic acid; in the second, there was only 13.3 of oxygen
and 34.9 of carbonic acid: the two gases had therefore diminished
considerably.
The variations of the carbonic acid are, as I said a while ago,
considerably more extensive than those of the oxygen, but are no
easier to explain: there is involved a collection of problems analo-
gous to those which we (MM. Mathieu and Urbain and I) have
already studied, and which would require very numerous experi-
ments.
And now having come to the point which should interest us
especially, a glance at the figures in Columns 8 and 9 of Table X,
compared to the corresponding figures of Columns 3 and 4, show us
that in all cases, under diminished pressure, the oxygen and the
carbonic acid have diminished in the arterial blood. There was no
exception to this general rule.
This is expressed very clearly in Figure 31 by the graphs com-
posed of dashes connecting the little circles o — o — o — . In this graph,
the quantities of gas are measured on the axis of the y's and the
pressures on that of the x's; the points on it have been determined
by the following procedure.
I took the figures which express the averages and which are
placed at the bottom of Table X. I assumed that the initial value,
at normal pressure, of the oxygen (Col. 3) was always 20, and that
that of the carbonic acid (Col. 4) was always 40. Then the values
at different pressures (Cols. 8 and 9) were modified by operations
like the following:
Average of the experiments from 1 to 4 —
Oa 19.3 (col. 3) : 20 = 16.9 (col. 8) : x = 17.5
CO2 37.7 (col. 4) : 40 = 33.2 (col. 9) : x = 35.2
Similarly, at each pressure, I made the same calculation, not
for the averages, but for the extreme values of the modifications,
and obtained thus the points marked by the little isolated circles
which accompany the two curves representing the averages.
The same data are expressed under a different form, perhaps
more simple, by Columns 12, 13, 14 and 15. Columns 12 and 13
608
Experiments
indicate the absolute quantity of the gases which have disappeared.
Columns 14 and 15, more instructive, express the proportion which
has disappeared and not the absolute quantity. They were ob-
tained by operations like the following:
Experiment No. 1 —
O2 . . 21.6 (col. 3) : 3.0 (col. 12) = 100 : x = 13.8 (col. 14)
CO . . 36.3 (col. 4) : 0.9 (col. 13) = 100 : x = 2.5 (col. 15)
Examining first Column 8, we see that the quantity of oxygen
IS
Fig. 31 — Decrease in amount of O and CO2 in the arterial blood, when
the barometric pressure is diminished.
Gases of the Blood 609
contained in the arterial blood could, at pressures of 30 or 40 cm,
drop to 9 cc. per 100 cc. of blood; that is, at these pressures the
arterial blood contained considerably less oxygen than ordinary
venous blood.
The diminution of the carbonic acid was likewise (Col. 9) very
considerable; the figures expressing the proportion of this gas have,
in fact, dropped almost to 20 cc. per 100 cc. of blood. We shall
refer later to the conclusions derived from these data.
In comparing the experiments made at the same degree of de-
compression, we find that the decreases in oxygen and in carbonic
acid have varied peculiarly. The lowest figures of Columns 8 and
9 are not at the end, but towards the middle of the table. The re-
sults of this fact are still more evident in Columns 14 and 15; there,
for example, at a pressure of 36 cm., that is, about a half atmos-
phere, the arterial blood has lost, in the different experiments,
from 36.1 to 55.6 per cent of its oxygen, and from 16.8 to 38.6 of
its carbonic acid.
It is difficult to explain these differences by the different be-
havior of the animals observed while the pressure was being
lowered. This element may be important; but it cannot be the only
one, and very probably animals with the same behavior may differ
in the result for the same decompression, some losing more and
others less oxygen or carbonic acid. This has interesting practical
results which I shall stress in their place.
Laying aside these individual differences, still more difficult to
study here than in the case of normal pressure, and blending them
in averages, we see (Col. 14) that on the average, the arterial blood
at a pressure of 56 cm. contains 13.6 per cent less oxygen than at
normal pressure; that at 46 cm., it contains 21.1 per cent less; at
36 cm., 43 per cent, and at 26 cm., 50.7 per cent. So at 26 cm., on
the average, half of the oxygen of the blood has disappeared.
These figures show that the diminution of this gas is far from fol-
lowing Dalton's Law, which would give, for the same decompres-
sions, losses of 26.3; 39.4; 52.6; 65.8 per cent.
• The losses of carbonic acid (Col. 15) for the same decompres-
sions, on the average, are 10.9; 14.0; 29.2; 38.2 per cent of the gas
existing at normal pressure; that is evidently still farther from
Dalton's Law.
These figures even show that the average loss of carbonic acid
is less than that of oxygen. The greatest proportion of loss, for the
former gas (Col. 15) was 41.8 per cent; for the second, we twice
had (Col. 14) 55.6. In one case, (Exp. CLXXII), at a pressure of
610 Experiments
46 cm., the quantity of carbonic acid had remained almost the
same as at normal pressure. These results are expressed in another
form in Columns 6 and 11, indicating the proportion of carbonic acid
and oxygen under different pressures. We see that at normal
pressure this proportion varied from 1.5 to 2.7, with an average of
1.9, whereas at low pressures it varied from 1.5 to 3.8, with an
average of 2.3. In almost all cases, the figure of Column 11 is
higher than the corresponding figure in Column 6, whether the
latter is high or low: the exceptions (Exp. CLXXV, CLXX,
CLXVII, CLXXIV) are cases in which the blood at normal pressure
contained small quantities of carbonic acid, varying from 29.1 to
35 cc.
These data can be expressed in a more precise manner by the
following formula:
The combination of oxygen with the hemoglobin is likely to
be partially destroyed, to be dissociated, at low pressures; this
dissociation becomes evident at a decrease of 20 cm. (pressure of
56 cm.). It increases as the decompression goes lower. At inter-
vals of 10 cm., we find the averages: from 56 to 46 cm., a loss of
7.5 per cent; from 46 to 36 cm., a loss of 21.9 per cent; from 36 to
26 cm., a loss of 7.7 per cent. The greatest loss then comes at
about a half atmosphere.
The graph Ox of Figure 32 shows at the first glance the course of
this gradual loss of oxygen; on the horizontal axis are counted the
pressures, and on the vertical axis the percentages of the gases
which have disappeared (Cols. 14 and 15 of Table X) .
As to the carbonic acid, it behaves in about the same way; only
its diminution is always less than that of the oxygen; this is
easily seen on the graph C02.
The graph shows again that the decrease in gases does not
follow Dalton's Law (which would be represented by a line bisect-
ing the angle of the coordinates). The carbonic acid is farthest
from it. Yet I must say that the deviation is not very great for
either gas.
That is very remarkable if we refer to current opinions about
the state of gases in the blood, according to the researches of M.
Fernet, classic today. First, the oxygen, chemically united to the
hemoglobin, could not be changed as to its proportion by decreased
pressure (or increased) ; now what happens is quite different, since
the decrease in oxygen is very evident and is quite near the re-
quirement of the law governing simple solutions.
The difficulty appears under an inverse aspect when we con-
Gases of the Blood 611
sider the carbonic acid. The experiments of M. Fernet have in-
spired the belief that most of the carbonic acid of the blood (0.964)
is in the state of simple solution in the liquid, and that a rela-
tively small proportion (0.597) is alone in the state of combination.
Now what we have just said makes this interpretation of M.
Fernet's experiments rather improbable. If the larger part of the
Fig. 32 — Percentage decrease of O and of CO2 in the arterial blood when
the barometric pressure is diminished.
carbonic acid was dissolved, the escape of the carbonic acid would
take place more easily and more regularly under the influence
of the decompression, and the graph C02 would be closer to the
bisecting line. Besides, we shall find in another part of this work
other reasons for thinking that the carbonic acid of the arterial
blood is, in the greater proportion, combined with carbonates and
phosphates, and that only a very small part exists in a state of
solution. However, these combinations are easily dissociated under
the influence of a decrease in pressure.
These contradictions to the conclusions of M. Fernet do not
imply any criticism of his important work. For we must note that
the experiments of this physicist were made in vitro, and at a low
temperature, whereas mine had as instrumental apparatus the
living animal itself. The presence of tissues, the continual con-
sumption of oxygen, the multiplicity of surfaces of contact with
612 Experiments
the blood and the air, the circulatory movements, the probable
formation during the absorption of oxygen of substances capable
of acting on the elimination of the carbonic acid, the increased
temperature of the living body, are conditions which existed in
one case and not in the other. Without mentioning the still en-
tirely unknown elements of the complex problem of respiration,
we have enough to give us an understanding rather than an ex-
planation of the differences in our results.
Furthermore, I wished myself to make experiments in vitro,
in which I should make changes in pressure much greater than
those obtained by M. Fernet. The report of these experiments will
form subchapter V of the present chapter.
The reader may have noticed that I studied the composition of
the blood gases beginning with 56 cm. Between 56 cm. and 76 cm..
I thought I should not take account of any of my experiments.
Here the value of the modifications found is precisely of the order
of the errors of analysis. To draw any conclusions, one would have
to make a considerable number of experiments and draw an aver-
age which would express the direction if not the real value of
the modification. Now this direction seems to me sufficiently de-
termined by what we know already. The decrease of the oxygen
and the carbonic acid of the blood, evident and constant at 56 cm.,
although very variable as to its value, surely begins considerably
sooner, but at barometric levels and with an intensity which must
vary from one animal to another, or in the same animal under
different circumstances.
On the other hand, all the experiments show that the oxygen
is always given off in greater proportion than the carbonic acid.
That should be enough to make us think that this rule extends to
the period included in the first 20 centimeters of lowered pressure,
a period which has this special importance of being the one to
whose influence the majority of dwellers in high places are sub-
jected.
If our table of experiments shows that we did not begin at the
outset of the decompression, it also shows that we did not go to the
end, that is, until the diminution of pressure becomes incompatible
with animal life. That was because my apparatuses did not permit
me to do so, since leaks which could not be avoided in such huge
receivers stopped the decrease of pressure at 17 cm., as I have said.
I tried to fill this gap by an indirect means. I put a dog under
the large glass bell- jar, and let it die there from decreased pressure.
Gases of the Blood 613
Then, taking it out as quickly as possible, I drew blood from its
left heart by means of a cannula.
Here are two experiments carried out in this way.
Experiment CLXXX. May 15. Dog weighing 5 k.; bell- jar of 31
liters. Left carotid exposed in advance.
5:40, put under the bell-jar, and the decrease of pressure begun,
maintaining a current of air.
5:47, pressure 45 cm.; was struggling, but now remains quiet.
5:50, 45 cm.; 17 respirations, deep; remains motionless; trembles.
5:53, 35 cm.; 17 respirations; motionless, head lowered; at 5:55, 12
respirations.
5:58, pressure 25 cm.; at 6 o'clock, 22 respirations; motionless.
6:05, 16 respirations; pressure brought to 15 cm., at 6:07, can no
longer remain half crouching, as it has done till now; lies down, its
nose resting on the floor to support its head; takes 28 enormous
respirations per minute. Pressure maintained at 15 cm.
6:10, 39 respirations less ample.
6:13, 35 cm.; at 6:15, 44 respirations; evacuation of fecal matter
without apparent effort; at 6:19, 40 respirations.
6:20, I close the intake valve; the pressure drops at once to 7 cm.
The dog rises on all fours, stiffens violently, but with slow regularity,
ceases to breathe, and sinks down dead.
I admit air: the animal's sides collapse. When taken out, it takes
two or three little inspirations while the cannula is being inserted into
the left heart. The heart is still beating a little; with much difficulty
32 cc. of very dark blood is drawn.
The lungs are red in wide patches, sinking in water, but unfold-
ing completely with insufflation. They are in a sort of fetal state. No
blood in the trachea or in the bronchioles.
The extracted blood contains per 100 volumes: CO 19.0; Oa 4.9.
Experiment CLXXXI. May 23. Dog weighing 4 kilos.
Took from the left carotid 33.3 cc. of blood.
6 o'clock. Put under the 31 liter bell-jar; pressure decrease begun.
6:06, pressure 40 cm.; at 6:08, 35 cm.; 14 respirations.
6:12, brought up to 45 cm.; 10 respirations.
6:15, pressure 31 cm.; rises, sits down, turns around.
6:17, pressure 26 cm.; seated with its head lowered, 15 respirations;
raises its head when the bell- jar is struck.
6:20, pressure 15 cm.; falls down, urinates, barks faintly and
plaintively.
6:21, pressure 13 cm.; gets up, barks, and falls back.
6:25, pressure 13 cm.; lying down, 9 respirations, medium.
Cock closed; the pressure falls slowly to 7 cm.; the animal seems
dead, when suddenly (6:27) it stands upright, stiffens slowly and
strongly, and falls back.
Pressure raised to 15 cm.; it seems better, moves a little; pressure
dropped to 7 cm.; dies without moving.
Withdrawn immediately. I extract without difficulty from the left
heart 50 cc. of very dark blood . . . . B
614 Experiments
At the first stroke of the pump, nothing comes. At the second,
about 3 cc; at the third, a considerable quantity of gas, and at the
fourth, almost nothing. The blood has not frothed perceptibly. Besides,
this is the same result as in the preceding experiment and is explained
by the small quantity of gas.
Blood A contained per 100 volumes: CO,' 35.0; O* 19.2
Blood B contained per 100 volumes: CO? 16.2; O- 8.1
These experiments do not permit us to draw any conclusions
as to the oxygen, because evidently at the return to normal pressure,
the oxygen of the air contained in the pulmonary vesicles was
partly dissolved in the blood of the lungs, which was then pumped
into the left heart. Moreover, the arterial blood was very red,
which had already perplexed F. Hoppe very much, as we saw in
the historical part of this book. But the carbonic acid is another
matter, and we can see that it was reduced to 19.0 cc. and 16.2 cc.
The proportion which had disappeared was, in Experiment
CLXXXI, 53.7 per cent.
Now, referring to Table X, we find at the pressure of 17 cm.
(Exp. CLXXIX) a much greater loss of 74 per cent. But in the first
place, this loss is not an average, since it is the result of only two
analyses made on the same animal, in the same experiment, one
at 18 cm., the other at 17 cm., with a 12 minute interval. Further-
more, to reach this enormous decompression, which I have not
been able to reach since, I had to keep an animal for one hour at a
pressure below 30 cm.
I will again call attention in this Experiment CLXXIX to the
very small proportion of carbonic acid which the blood retained
in passing from 17 to 26 centimeters pressure (analysis D) , in spite
of a quarter hour interval. I thought I should not include this
figure, Number 17, Table X, in the average of Column 15 and in the
graph of Figure 32, which expresses it.
Another interesting point, on the contrary, is the return of nor-
mal proportions of oxygen and almost normal proportions of CO.
when the animal was restored to the pressure of 76 cm. (three
quarters of an hour afterwards). I have had numerous examples
of this return of the gases, examples still more rapid.
As for the figures of the analyses B, C, D (Numbers 20, 21, 17
of Table X) , I think we must consider them as minima for carbonic
acid, and I preferred to set down on the graph C02 of Figure 31
the results furnished by the experiments at 7 centimeters, which
seem to be nearer the average and to comply better with the law of
the graph.
It would be easy for me now to draw practical conclusions from
Gases of the Blood 615
the consideration of the preceding data, and show what happens
to the blood of travellers who, either in a balloon, or on a mountain
side, are subjected to considerable diminutions of pressure. But I
think that these reflections will be better placed in the third part
of this work, when I shall deduce from the whole collection of ex-
perimental data the explanation of the symptoms produced by the
modifications of pressure. I shall here merely summarize in this
simple formula the results obtained above:
When the pressure is lowered, the quantity of gases contained
in the blood is equally diminished, but in a proportion a little less
than that which Daltoji's Law would indicate; the blood thus loses
relatively more oxygen than carbonic acid.
Subchapter III.
GASES OF THE BLOOD AT PRESSURES GREATER
THAN ONE ATMOSPHERE
1. Experimental Set-up.
The apparatus which I use for extracting the blood of animals
subjected to pressures above that of the atmosphere consists (Fig.
33) of a straight cylinder of sheet steel 4 millimeters thick. The
middle part of the cylinder is circular while the extremities are
elliptical. The joints are fastened by many very small bolts. The
elliptical form permits the insertion of the doors which close the
extremities of the cylinder and which turn on the short axis.
These doors consist of a cast-iron frame in the middle of which
is fastened a glass porthole 18 millimeters thick, with a diameter
of 10 centimeters. They are put in place by holding them obliquely
and inserting them into the cylinder; then pulled back, they meet
the edge and close hermetically by use of a rubber gasket. Two
arms furnished with screws keep them in place; the inner pressure
towards the outside does the rest.
The total length of the cylinder is 1.50 meters; its diameter, in
the circular part, is 40 centimeters; the total capacity therefore is
about 153 liters.
Compression is made by a compression pump C of the Rouquay-
rolle and Denayrouze system, operated by a gas engine whose
coupling gear A works the gears B; the air laden with water vapor
which is thrown off by this pump and whose temperature rises
616
Experiments
considerably, is conveyed through a coil immersed in cold water D,
furnished with a reservoir E for the condensed water.
A cock a makes or closes connection with the pump.
Another cock c, whose opening can be enlarged progressively,
permits one to extract air from the receiver for analysis, to main-
tain a current of pure air under pressure, or to obtain a very sudden
decompression. The manometer b indicates the pressure.
Gases of the Blood 617
The cock d, placed on the slope of the inner lining of zinc,
allows urine or the condensed water to be extracted. Finally, in f
is a large orifice, which can either be closed by a screw-head, as
the figure shows, or allow the insertion of a thermometer, a serre-
fine with a handle, a cannula, etc. To prevent the air from escap-
ing around these instruments, they are put through a rubber ball,
(B. Fig. 34) held in a copper ring, whose screw thread closes it at
will. This arrangement, while completely shutting out the air,
gives the instruments a mobility which may be useful.
When one wishes to see what is going on in the apparatus, he
puts a candle opposite one of the glass portholes, and looks through
the other; a dangerous proceeding, for it was under these conditions
that the explosion occurred of which I shall speak in another
chapter.
The dog on which the operation is to be carried out is tightly
fastened, the nose held in a muzzle, on a framework of iron and
wood, whose form fits the inner wall of the apparatus, so that the
animal, once placed within it, cannot change its position. Into one
of its carotid arteries A is introduced a metal cannula S, which
can, when the animal is in position, be joined to a copper tube,
which screws through the wall of the apparatus, and is provided
on the outside with a cock R.
These arrangements having been made, cock R is closed, and
the serre-fine SF is placed in the carotid, thus preventing the blood
from entering the cannula. Then the door of the cylinder is ad-
justed and the compression begun; it rises easily at the rate of
about one atmosphere every four minutes, when all the cocks are
tightly closed. It therefore takes about 40 minutes to reach 10
atmospheres, the maximum pressure which I have attained with
this apparatus.
Nothing now is more simple than to extract the blood of the
animal, when the desired pressure has been reached. One needs
only to open cock R and remove the serre-fine SF to see the carotid
blood gush out with extraordinary force. In these conditions, in-
deed, the animal is like a sponge powerfully squeezed by a force
corresponding to 1.03 kilos, multiplied by the number of atmos-
pheres and by the exterior surface of its body. The whole proce-
dure then consists of fitting the glass syringe of Fig. 23 to the thick
rubber tubing which adheres to the cock. Opening the cocks with
precaution, one sees the plunger of the syringe raised vigorously by
the pressure of the blood. One must not fail to fit its own cock to
the syringe, and to close it immediately when one has secured the
618
Experiments
desired quantity of blood, so as to prevent the gases, which are
often given off, from escaping. When this discharge was con-
siderable, I weighed the syringe to get the quantity of blood,
volume readings then becoming very inexact.
2. Experiments.
fig. 34 — Extraction of blood from an animal placed in compressed air.
Here now is the detailed account of the experiments made in
the conditions specified above.
Experiment CLXXXII. July 23. Dog weighing 12 kilos.
Drew from left carotid 36 cc. of blood .... A
4:30. Put into compression apparatus, and air compressed with
current passing through; at 5:08, pressure of 10 atmospheres reached.
Gases of the Blood 619
5:15, drew 36.7 gm. (cc?) of very red blood; gases escape in the
syringe, and the blood begins to coagulate very quickly . . . . B
Brought in 2 minutes to 6 atmospheres, and kept at this pressure
under a current of air; at 5:45, drew 39.7 cc. of blood a little less
red; no free gas . . . . C
Brought suddenly to 3 atmospheres, and kept under a current
of air.
6:33, drew 38.2 cc. of blood; no free gases . . . . D
Decompression made slowly. At 7 o'clock, the animal is well; it
survives without ill effects.
Blood A (1 atm.) contains per 100 volumes: O^ 19.4; CO 35.3; N 2.2
Blood B (10 atm.) contains per 100 volumes: O 24.6; CO 36.4; N 11.3
Blood C (6 atm.) contains per 100 voolumes: O2 23.7; CO 35.6; N 8.1
Blood D (3 atm.) contains per 100 volumes: O 20.9; CO- 35.1; N 4.7
Experiment CLXXXIII. July 27. Female dog weighing 9 kilos.
Drew 29.5 cc. of blood from the carotid .... A
Put into compression apparatus; before each blood extraction, I
maintain the determined pressure, under a current of air, for several
minutes.
3:21, drew 29.5 cc. of blood at 2 atmospheres . . . . B
3:48, drew 34.3 cc. of blood at 5 atmospheres . . . . C
4:35, drew 38.2 cc. of blood at IV2 atmospheres . . . . D
Up to this time, no discharge of gas in the syringe.
5:15, drew 30.7 cc. of blood at 10 atmospheres; here, small bubbles
of gas .... E
Decompressed in 30 minutes; died.
The rest of its story will be told in Chapter VII.
Blood A (1 atm.) contains per 100 volumes: 0= 18.3; CO^ 37.1; N 2.2
Blood B (2 atm.) contains per 100 volumes: O 19.1; CO 37.7; N 3.0
Blood C (5 atm.) contains per 100 volumes: O 20.6; CO? 40.5; N 6.1
Blood D (7V2 atm.) contains per 100 volumes: O 21.1; CO^ 36.8; N lost
Blood E (10 atm.) contains per 100 volumes: O- 21.4; CO 36.8; N 11.4
Experiment CLXXXIV. August 5. Female dog weighing 11 kilos.
Drew 29.5 cc. of blood from the carotid .... A
Put into the apparatus at 5:33. Same precaution as in the pre-
ceding experiment.
5:53, 3 atmospheres; drew 29.5 cc. of blood; the discharge of gas
is evident . . . . B
6:28, 6 and 3A atmospheres; drew 29.5 cc. of blood; further dis-
charge of gas . . . . C
The animal cries and whimpers.
7:10, 9V4 atmospheres; drew 36 cc. of blood; gas in abundance . . D
The cock of the cannula is opened wide; there issues 250 gm. of
very red blood, which coagulates immediately; much gas is discharged.
Decompressed rapidly, the animal dies immediately. The rest of
its story in Chapter VII.
Blood A (1 atm.) contains per 100 volumes: O? 18.4; CO* 47.7; N 2.5
Blood B (3 atm.) contains per 100 volumes: O 20.0; CO 42.2; N 4.4
Blood C (6% atm.) contains per 100 volumes: O2 21.0; CO2 41.3; N 7.1
Blood D (9y4 atm.) contains per 100 volumes: O 21.2; CO 39.8; N 9.3
620 Experiments
Experiment CLXXXV. August 7. Female dog weighing 8.5 kilos.
Drew at normal pressure 31.9 cc. of blood; the animal loses also,
by accident, about 35 cc A
5:25, 5 atmospheres; drew 30.7 cc. of blood, from which bubbles of
gas are discharged . . . . B
6:05, 8 atmospheres; drew 31.9 cc. of blood; numerous bubbles . . C
6:33, 10 atmospheres; drew 33.8 gm. of blood; gases were dis-
charged in abundance, and coagulation threatened to take place rap-
idly . . . . D
Decompressed; the end of its story in Chapter VII.
Blood A (1 atm.) contains per 100 volumes: O 22.8; CCh 50.1; N 2.3
Blood B (5 atm.) contains per 100 volumes: O* 23.9; CO 35.2; N 6.0
Blood C (8 atm.) contains per 100 volumes: O 25.4; CO* 37.6; N 9.5
Blood D (10 atm.) contains per 100 volumes: Cb 25,2; CO 39.0; N 10.0
Experiment CLXXXVI. August 8. Dog weighing 12.5 kilos.
Drew 33.8 cc. of blood at normal pressure, from right carotid . . A
Put into apparatus at 4:45.
5:33, 5V2 atmospheres; drew 32.9 cc. of blood; discharge of gas . . B
6:41, 10 atmospheres; drew 36.1 gm. of blood; gas in abundance in
the syringe . . . . C
Decompressed; the end of its story in Chapter VII.
Blood A (1 atm.) contains per 100 volumes: Ch 20.2; COa 37.1; N 1.8
Blood B (5V2 atm.) contains per 100 volumes: O* 23.7; CO 35.5; N 6.7
Blood C (10 atm.) contains per 100 volumes: O2 24.7; CO 37.9; N 9.8
These different results are arranged in Table XI, by increasing
order of pressures.
If now we examine the figures it contains, which is easily done
by an inspection of Columns 12, 13, and 14, in which are indicated
the modifications in percentages of the volume of the gases ex-
tracted from the blood under pressure, we see at first glance: 1)
that the oxygen and nitrogen have always increased; 2) that the
carbonic acid has sometimes increased and sometimes diminished.
This can be shown in clearer form by making the following
calculation on the different numbers.
We shall assume that, at normal pressure, the blood always
contains 20 volumes of oxygen, 40 volumes of carbonic acid, and
2.2 volumes of nitrogen; the quantity contained at the other pres-
sures will be easily deduced from a proportion.
And so, for the first experiment listed in the table, the propor-
tions will be at 2 atmospheres:
CO
N
18.3 : 20 = 19.1 : x = 20.9
37.1 : 40 = 37.7 : x = 40.7
2.2 : 2.2 = 3.0 : x = 3.0
Gases of the Blood
621
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622
Experiments
Making averages for identical pressures, we can draw up the
following table:
Table XII
1
1 2
3
4
Atmospheres
| Oxygen
co2
N
1 _ .
20
40.0
2.2
2
20.9
40.7
3
3
21.6
37.2
3.9
5 (Exp. 4, 5, 6)
22.7
35.7
6
7 (Exp. 7, 8, 9, 10)
23.1
35.5
7
10
23.4
36.6
9.4
The results of this table are expressed in a very striking way
by the following graphs (Fig. 35), in which the pressures are
plotted on the horizontal axis, and the quantities of gas on the
vertical scale.
Let us now examine the data for each of the three gases of the
blood, using the figure and the two tables.
1. Oxygen. Its increase, we have said, is constant. But the
comparison of Columns 3, 8, and 12 of Table XI shows us that this
increase is, at the same time, very variable for the same pressure,
and very small even under the enormous pressure of 10 atmos-
pheres.
The variety of results should not surprise us, after what we
have already seen in speaking of decreases in pressure, and after
the inequalities indicated by the diverse figures in Column 3. It is
impossible for us to connect this variety of results to any known
condition; but it is very interesting to observe, because it can
serve to give account of the intensity, very variable according to
the subjects, with which the air compression acts.
As to the amount of this increase, it is really very curious to
see how slight it is. Its maximum, under a pressure of 10 atmos-
pheres, was 26.7 per cent, that is, in volume the quantity of oxygen
contained in 100 cc. of arterial blood rose from 19.4 cc. to 24.6 cc.
The figures relating to intermediary pressures have the same bear-
ing. The graph Ox and Column 2 of Table XII show this slowness
of increase with great definiteness.
We had already seen, moreover, by experiments made in ex-
panded air, that the influence of barometric pressure, relative to
the quantity of oxygen absorbable, is less for pressures near 76 cm.
than for those which are much lower. So the figures in Column 14
of Table X show that in passing from 76 cm. to 56 cm. the oxygen
lessens only by 13.6- per cent, whereas in passing from 56 cm. to
36 cm. it lessens 43—13.6=29.4 per cent. So the graph Ox (Fig. 31) ,
Gases of the Blood
623
which shows the changes in the oxygen content of the blood with
changing pressure flattens out in the neighborhood of normal
pressure.
Fig. 35 — Variations of blood gases at pressures higher than one atmosphere.
We can show this in a still clearer manner in another graph
(Fig. 36). Let us take as the zero the barometric vacuum, let us
plot the pressures in atmospheres on the axis of the x's, and let us
put on the axis of the y's values proportional to the oxygen content
624
Experiments
at different pressures, and we thus obtain a curve Oab (graph and
vertical lines dotted) which, after rising very rapidly in the region
BBSS
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of zero to xk atmosphere, a little less in the region of Vz to 1 atmos-
phere, levels off considerably, beyond that pressure.
The figures are no less clear; assuming that the zero of the
oxygen corresponds to the lethal decompression of 7 to 8 centi-
Gases of the Blood 625
meters, equal to 1/10 of an atmosphere, we see, by combining
Tables X and XI, that:
From 1/10 to V* of an atmosphere, the proportion of oxygen has increased 7.5
From Va to Vz of an atmosphere, the proportion of oxygen has increased 5.7
From Vz to % of an atmosphere, the proportion of oxygen has increased 4.3
From % to 1 of an atmosphere, the proportion of oxygen has increased 2.5
From 0 to 1 atmosphere, the proportion of oxygen has increased 20.
From 1 to 2 atmospheres, the proportion of oxygen has increased 0.9
From 2 to 3 atmospheres, the proportion of oxygen has increased 0.7
From 4 to 5 dividing by 2 the difference from 3 to 5 = 1.1 increased , Q'5
From 5 to 6 atmospheres, the proportion of oxygen has increaed 0.2
From 6 to 7 atmospheres, the proportion of oxygen has increased 0.2
From 7 to 8 atmospheres, the proportion of oxygen has increased 0.1
From 8 to 9 atmospheres, the proportion of oxygen has increased 0.1
From 9 to 10 atmospheres, the proportion of oxygen has increased 0.1
Total 23.4
In other words, these data show that, in the living organism,
the absorption of oxygen by the blood increases very rapidly for
pressures less than one atmosphere, but very slowly, on the con-
trary, for pressures of several atmospheres. Everything seems to
indicate that there exists, in the neighborhood of normal pressure,
a point of chemical saturation of the oxy-hemoglobin, and that be-
yond this point there is added to the blood only the oxygen dis-
solved in the serum according to Dalton's Law. This will be veri-
fied when I speak of the experiments performed in vitro on blood
taken from the vessels.
At the proper time we shall return to the reflections inspired
by these interesting data. For the moment, let us be satisfied
with observing that a laborer who works at a pressure of 2 to 5
atmospheres has not much more oxygen in his blood than at normal
pressure. Moreover, — and this is not to be overlooked in explain-
ing the unevenness of the phenomena displayed by the different
workmen — I have seen animals which normally had in their blood
at normal pressure more oxygen than others at 10 atmospheres;
and also in the experiments at diminished pressure certain of my
dogs had at normal pressure (See Table X, Experiments 4 and 11)
less oxygen than others at a pressure of 56 centimeters and even
of 44 centimeters (Experiments 1, 2, 5, and 8).
2. Carbonic acid. As Table XI shows (Columns 4, 9, 13) , some-
times it increases, sometimes it diminishes. Its increase is always
very slight (at the most, 9.2 per cent, that is, in actual quantity,
3.4 cc. per 100 cc. of blood) ; its decrease was very great (up to 29.7
626 Experiments
per cent, that is, 14.9 cc. per 100 cc. of blood [in original French,
110 cc.]) . All that the figures permit us to say is that the carbonic
acid always diminished when its original proportion exceeded 38 cc.
per 100 cc. of blood.
The averages, represented, according to the agreement fixed
above, by Column 3 of Table XII and by graph CO2 of Figure 35,
indicate a decrease, irregular, it is true, but constant. However,
one may say that it is established, as a general fact, that the increase
of pressure above normal pressure does not change very consider-
ably the carbonic acid content of the blood. The result was quite
different, as we have seen, for pressures below one atmosphere;
but we had already seen, in the neighborhood of 76 cm., that the
carbonic acid varies little, and in the figures of Column 14, for the
pressure of 56 cm., we find the very low ones of 2.5 per cent and
0.8 per cent. On the contrary, at the pressure of 36 cm., for ex-
ample, the blood contains an average of 29.2 per cent of carbonic
acid less than at normal pressure, which corresponds to an average
loss of 11.4 cc. per 100 cc. of blood.
The important practical conclusion derived from this fact is
that the symptoms observed in men and animals subjected to high
pressures cannot be attributed to the effect of carbonic acid. We
shall return to this point.
If now we ask ourselves how it happens that the carbonic acid
diminishes for very low pressures, without increasing above one
atmosphere, the answer is hard to find. I have, however, settled
upon the following explanation.
The respiratory exchanges are not made, as we say in common
parlance, between the blood of the lungs and the air of the atmos-
phere. If it were so, this air, containing only very slight traces of
carbonic acid, would play in respect to the blood with reference to
the carbonic acid the role of a vacuum, and only a very small
quantity would remain in the blood. But the exchanges are made
between the venous blood and the air of the pulmonary vesicles.
Now I found earlier 7 that this air, even after an inspiration, still
contains from 6 to 8 per cent of carbonic acid. M. Grehant,8 who
later did the same research by a method quite different from mine,
reached a result as near mine as one could desire in such a subject.
It is therefore the normal presence of this important proportion of
carbonic acid in the air of the alveoli which maintains the usual
quantity in the blood; this gas is thus its own obstacle, and one can
easily see how an exaggerated pulmonary ventilation, lessening the
Gases of the Blood 627
proportion of C02 in the alveolar air, lessens it at the same time in
the blood.
This carbonic acid which remains thus in the lungs represents
the regular excess of the carbonic acid formed in our tissues over
that which is exhaled through the trachea. This quantity will not
vary, if no change is made in the conditions of metabolism and of
pulmonary ventilation. Now this seems to be the case during
respiration in compressed air, at least for the phenomena that are
gross and apparent. If then there is produced during the same
time the same quantity of CO,, the quantity which will remain in
the air of the lungs will be the same; but as this quantity is com-
pressed, its volume decreases inversely as the pressure, and it is
clear that then its percentage in the air of the lungs, whose total
volume does not change, will diminish directly as the volume. So
if the air in the lungs of an animal at normal pressure contained
6 per cent of C02, at 2 atmospheres it will contain only 3 per cent,
at 3 atmospheres 2 per cent, at 6 atmospheres 1 per cent, etc.
Now since the pressure exerted by this carbonic acid upon the
carbonic acid of the blood evidently has as a measure the product
of the percentage by the barometric pressure, it will be expressed
in the different cases mentioned above: at normal pressure, by
6x1 = 6; at 2 atmospheres, by 3x2 = 6; at 3 atmospheres by
2x3 = 6; etc., that is, its value always remains the same. It is
therefore not astonishing that the carbonic acid content of the blood
does not vary either.
But why does it diminish in very low pressures? In this case,
the same reasoning, the same conclusions, apparently. But here
the question becomes complicated. First, if we assume that the
animal is at a pressure of a half -atmosphere, the proportion of car-
bonic acid in the lungs will rise to 12 per cent; the oxygen content
of the air in the pulmonary vesicles is thus diminished, and the
animal is forced to maintain a more active ventilation which, les-
sening the tension 12 x % = 6, lets more acid escape from the blood.
But the principal reason lies elsewhere than in the decrease of
barometric pressure; we shall see later, in fact, that the carbonic
acid content of the blood diminishes merely from breathing an air
with a smaller oxygen content. It is therefore in the troubled
chemical conditions of the formation of CO, that we must seek the
most important cause of this diminution. No doubt the same thing
is true of the diminution which coincides with pressures above one
atmosphere.
3. Nitrogen. For this last gas, matters should take place with a
628 Experiments
great simplicity, and, in fact, they do so. As it enters into no com-
bination, its proportion in the blood depends solely on pressure; so
Columns 5, 10, 14 of Table XI show us that it increases considerably.
We shall see what is the importance of this considerable quantity
of nitrogen when we speak of the effects of sudden decompression.
And yet, strangely enough, the increase is far from following
Dalton's Law. In fact, at 5 atmospheres, for example, we find in
Column 5 the average number 6, instead of 11 required by Dalton's
Law; at 10 atmospheres, the average number is 10.4 instead of 22.
There is therefore about half as much nitrogen as the law would
require. That is very striking in the graph Az in Figure 35, in
which the straight line shows what the law would require.
This fact is very instructive, because it shows how incomplete
the intrapulmonary agitation is, at least at high pressures. Now
the results given by the oxygen tend in the same direction. Ad-
mitting that the hemoglobin is saturated chemically with oxygen
in the neighborhood of normal pressure, the quantity of oxygen
dissolved should be much greater at high pressures than experience
indicates. At 10 atmospheres, for example, we should find, not
23.4 per cent, but about 29. The insufficient mixing of the air in
the lung should be considered here; furthermore, this insufficiency
is evident at normal pressure, because blood extracted from the
artery always gains considerably in oxygen content from agitation
with the air. We shall see that the same thing is true in the case
of high pressures.
All this can be summed up in the following sentence: in the
living animal, when the barometric pressure increases, the oxygen
increases in the arterial blood, but very slowly; the nitrogen in-
creases more quickly, but in a quantity far from that required by
Dalton's Law; as for the carbonic acid, it almost always diminishes.
Subchapter IV
GASES IN THE BLOOD IN ASPHYXIA COMPARED
TO DECREASED PRESSURE
I think I demonstrated in the first chapter that the symptoms
and death in expanded air are the result of weak pressure of out-
side oxygen, and that, in a word, it is a matter of simple asphyxia
from lack of oxygen.
If this is so, one should, in the blood of a dog subjected to
Gases of the Blood
629
asphyxia, find the same low gas content as in the blood of dogs
subjected to decompression.
To verify this hypothesis, two methods are possible: 1) to place
an animal in a current of air, which becomes progressively poorer
oj
o
< &
CO
X2 <u
•° .2
tuo "3
Q °
in oxygen; 2) to have the animal exhaust a certain quantity of air,
getting rid of the carbonic acid, of course, as it is formed.
The first method seemed to me impractical. To use the second,
I fitted to dogs a muzzle which communicated with a bag contain-
630 Experiments
ing from 130 to 150 liters of air; at the expiration as at the inspira-
tion, the air bubbled through a potash solution intended to rid it
of its carbonic acid, in which, let me say in passing, I was not
entirely successful: the air of the bag always contained from 1 to 2
per cent of this gas.
Figure 37 shows the set-up of the experiment. The inspired air
and the expired air pass through the flasks A and B, where a
potash solution acts as a valve; in A, the tube which communicates
with the dog ends at the top of the flask; through it the inspiration
is made; in B, it descends and dips down a little into the liquid;
through this the expiration is made.
The experiment having been set up in this way, from time to
time I took samples of air from the bag and blood from the carotid
for analysis.
Here are the results of some experiments.
Experiment CLXXXVII. April 1; mastiff dog, weighing 11 kilos.
Bag containing 137 liters of air. Temperature 15°. Experiment begun
at 2:35.
2:36; 16 respirations; pulse 144; arterial pressure varying from
12.5 cm. to 17 cm.; rectal temperature 39°. Took 25 cc. of blood from
the carotid, light red; contains per 100 cc. 19 of oxygen and 48 of
carbonic acid.
The animal is very calm and remains very calm all through the
experiment.
2:55; respirations, 16; pulse, 96.
3 o'clock; took air from the bag; contained 02 18.1; C02 0.8.
3:05; respirations, 15; pulse, 78; temperature 39°. Took 25 cc. of
blood, very red; contained 02 17.0; CO, 49.0.
3:30; respirations, 20, long; pulse, 64; pressure of 13 cm. to 20 cm.;
temperature 38.8°. . •
3:35; took air from the bag; contained O, 15.9; CO, 1.0. Took
25 cc. of blood, red; contained O, 15.0; CO, 46.5.
4 o'clock; respirations, 12; pulse, 52; temperature 38.5°.
4:05; air contained 02 14.1; CO, 1.3. Took 25 cc. of blood, less
red; contained 02 13.6; CO, 46.3.
4:20; cardiac pressure from 11 to 18 cm.
4:30; respirations, 12; pulse, 40; temperature 38.2°. Air contained
O, 12.2; CO, 1.7. Took 25 cc. ofblood; analysis lost.
5 o'clock; respirations, 12; pulse, 40; temperature 38.0°.
5:10; air contained O, 9.6; CO, 2.0. Blood 25 cc, still quite red;
contains 02 12.0; CO, 46.3.
5:20; pressure from 12 to 18 cm.
5:36; respirations, 12; pulse, 64, very irregular; temperature 37.5°.
Air from the bag contained 02 7.1; CO, 2.2.
6 o'clock; respirations, 14; pulse, 104; temperature 37.5°. Took
blood, 25 cc, quite dark; contained 02 7.1; C02 42.8.
6:10; air of the bag contained 02 5.9; CO, 2.1.
Gases of the Blood 631
6:25; cardiac pressure, from 11 cm. to 15 cm.
6:30; respirations, 20; pulse, 92, very irregular; temperature 36.6°;
the expirations become more abrupt; the animal's feet are still sensi-
tive.
6:35; air of the bag contains O, 4.6; C03 2.2. Blood 25 cc, dark;
contained O, 5.0; CO, 36.7.
7 o'clock; respirations, 24, with very abrupt expirations; pulse, 84;
temperature 35°. Feet still sensitive.
7:05; air of the bag contains 02 2.7; C02 1.9.
7:15; the phenomena are appearing rapidly; the dog has just lost
sensitivity of the eye suddenly. Respirations, 4; pulse, 56; temperature
34.5°; cardiac pressure, about 4 cm. Took 25 cc. of blood, very dark;
contains O, 0.; CO. 20.6.
Last breath at 7:17.
We shall return to the different details of this protocol; but
limiting ourselves for the moment to what concerns the gases of
the blood, we can summarize the results of the analyses as follows:
The air contains 100 cc. of blood contain
Oxygen Oxygen CO,
At the beginning i 20.9 19 48
After V2 hour 18.1 17 49
After 1 hour 15.9 15 46.5
After 1V2 hours 14.1 13.6 46.3 .
After 2 hours 12.2 •
After 2% hours 9.6 12. 46.3
After 3 hours 7.4 7.6
After 3 hours, 20 minutes 7.1 42.8
After 3V2 hours 5.9
After 4 hours 4.6 5. 36.7
After 4 hours, 40 minutes 2.7 20.6
Experiment CLXXXVIII. April 4. Dog weighing 10.600 kilos. Bag
containing 137 liters of air. Temperature 15°. Experiment begun at
2:05.
2:07; respirations, 24; pulse, 92; temperature 38.5°; cardiac pres-
sure from 12.5 cm. to 18.5 cm. Took 25 cc. of blood, very red; con-
tained per 100 cc. O, 18.2; CO. 50.8.
Slight agitation.
2:35; respirations, 20; pulse 100, irregular; temperature 38.2°
Took air which contained: O^ 17.9; CO- 0.9.
3:05; respirations, 18; pulse, 90; cardiac pressure has not changed;
temperature 38°. Took air: O, 16.3; CO, 1.6; drew 25 cc. of blood,
very red; contained: O^ 16.6; CO^ 47.7.
3:35; respirations, 18, expirations prolonged; pulse, 72; temperature
37°. The air contained O? 14.8; CO^ 1.7.
4:05; respirations, 16; pulse, 90; pressure of 12.5 cm. to 17.5 cm.
Air, O, 13.4; C02 1.9. Red blood, 25 cc, contains O, 15.9; CO.- 45.1.
4:35; respirations, 16; pulse, 112; temperature 37°. Air, O2 10.4;
CO2 1.7.
632 Experiments
5:05; respirations, 24; pulse, 94; temperature 36.2°. Air, O 8.3;
CO* 2.5. Took blood, quite dark; O2 9.8; CO 40.2.
5:35; air, O2 6.2; CO* 1.7.
5:50; respirations, 28; pulse, 148; temperature 34°. Very dark
blood, 25 cc, contains O 6.7; CO 37.9.
5:58; Sudden violent struggling, after which the animal falls back,
as if conquered, and thenceforth remains quiet.
6:05; air, O2 4.0; CO 1.6.
6:20; pulse, 68; pressure from 8 cm. to 17 cm.; feet sensitive.
6:30; respirations, 16; pulse, 68; temperature 34°.
6:35; air, O 3.0; CO 0.8.
6:40; took 25 cc. of blood, very dark, which contained: O 0.7;
CO 25.0.
The respirations slacken when I begin to draw blood; they cease
at 6:45; I immediately draw blood which shows no trace of oxygen.
Summary:
The air contains The blood contains
Oxygen Oxygen CO2
At the beginning 20.9 18.2 50.8
After V2 hour 17.9
After 1 hour 16.3 16.6 47.7
After IV2 hours 14.8 ■
After 2 hours 13.4 15.9 45.1
After 2V2 hours 10.4
After 3 hours 8.3 . 9.8 40.2
After 3V2 hours 6.2 .
After 3% hours 6.7 37.9
After 4 hours 4
After 4V2 hours 3 0.7 25
The results of these two experiments are expressed on the fol-
lowing graph (Fig. 38), whose lines show the simultaneous vari-
ations of the oxygen of the air and the gases of the blood. The
solid line relates to Experiment CLXXXVIII; the dotted line to
Experiment CLXXXVII.
Here now is an experiment in which from the very outset a dog
was made to breathe air low in oxygen:
Experiment CLXXXIX. May 20. At 3:30, the animal breathing
ordinary air, 28 respirations, pulse 136; cardiac pressure, from 18 to
20 cm.
Its blood contains: O2 21.5; CO2 47.3.
4:30; the dog is made to breathe through the potash valves, from
a bag containing air with only 10 per cent of oxygen; it remains quiet.
5 o'clock; respirations, 16; pulse, 128; pressure, 16 to 19 cm.
5:30; respirations, 16; pulse, 116. Dark blood, contains: O2 5.3;
CO2 45.7.
6 o'clock; respirations, 16; pulse, 80; pressure, from 8 to 13 cm.
6:30; respirations, 16; pulse, 56.
6:45; respirations, 8; pulse, 24.
Gases of the Blood
633
Dies at 6:53; I immediately draw with a cannula 25 cc. of blood
from the left heart, which contains 02 0; C02 29.
The air of the bag contains 2.5 of oxygen.
Let us refer now, from the special point of view which interests
us, to the two experiments CLXXXVII and CLXXXVIII. The pre-
ceding graph shows us that the oxygen of the blood diminished just
as fast as the tension of the oxygen of the air; that is not surprising,
no
JO 40
1
in so
10 20
5 10
1
1
^H
X"4;
\
\
£
,' Ji
I
"^
%,\ Co? du
\ Sana
"^
~~~+\
X
\
j
^T\S
X
0 0
V* VAir
\ Ox.Ju
1
> lh 2h 3h 4K .0 V?
Fig. 38 — Variations in the gases of the blood and the oxygen of the air in
asphyxia in closed vessels, the carbonic acid being absorbed: to
make the figure clearer, the ordinates corresponding to the oxy-
gen content of the air are twice the height of the others.
634 Experiments
but it is stranger to see that the carbonic acid diminished equally,
although a considerable quantity remained in the air of the bag,
which should have increased the proportion of this gas.
If we wish to compare, not the trend, which quite evidently is
the same, but the exact value of the variation of the blood gases in
diminished pressure on the one hand, and in asphyxia on the other,
we need only take the graph in Figure 31 and add to it the average
results of the last experiments, making the same calculation of the
numbers to bring the original value of the oxygen to 20, and that
of the carbonic acid to 40.
This has been done in Figure 39.
On the ordinates are plotted, as usual, the numbers relating to
the percentages of the gases extracted from the blood.
The abscissae measure both the percentage of ambient oxygen
and the barometric pressure. So 20.9 corresponds to 76 centimeters;
20.9
a half-atmosphere, 36 centimeters, corresponds to , etc. . . .;
2
that will permit us to see whether or not there is agreement be-
tween the results of the two kinds of experiments.
The points relating to diminutions of pressure are marked, as
we have already said, by little circles connected by dashes and dots
— . — .o. — . — . — o. The dotted lines express the average of
the two experiments of simple asphyxia which I have just reported.
Now in regard to the oxygen, we notice at once the remarkable
agreement existing between the two curves; only for the rarefied
air, as I have already indicated, I could not go below a pressure of
17 centimeters, corresponding to about 4.7 per cent of oxygen. Here
is the first point gained.
For the carbonic acid, the agreement is less perfect. But we
must note first that there remained in the air on the way to ex-
haustion a certain quantity of carbonic acid, without which the
dotted graph would certainly have dropped more than it has.
Furthermore, the irregularities between the averages connected by
the line — o. — .o are very great for the carbonic acid, as is shown
by the little isolated circles, which correspond to each of the ex-
periments. It is therefore probable that from a very great number
of experiments we should obtain averages which would be closer
together; but it seemed to me unimportant to continue this investi-
gation.
The great interest lay in showing that, even at normal pressure,
if the proportion of oxygen in the respirable air is low, we find in
Gases of the Blood 635
the proportions of oxygen and carbonic acid in the arterial blood
the same modifications as in the case of respiration under dimin-
ished pressure. From this survey, as from that in the first chapter,
91 HI M HSSBI HHB
Fig. 39 — Variations in the blood gases in asphyxia compared to decreased
pressure,
636
Experiments
there appears once more the proof that decompression acts as a
simple asphyxiating agent.
When this truth had been established, it became possible for
me to find out how the gases of the venous blood vary during de-
compression. I had tried repeatedly to extract the venous blood
of a dog placed in my large cylinders; difficulties which all experi-
menters will divine had prevented me from succeeding; clots
formed in the cannulas, air bubbles, which the pressure of the
blood no longer opposed, rushed into the right heart, etc.
But respiration in an air whose oxygen content was gradually
lessened allowed me to avoid these difficulties. And so I did in the
following experiments.
Experiment CXC. July 30. Dog weighing 12 kilos. Muzzle hermeti-
cally closed.
2:05; Forced to breathe with the potash valves from a bag con-
taining 90 liters of air.
2:10; respirations, 26; pulse, 100. Drew from the carotid 25 cc.
of blood, not very red .... A
2:20; Drew from the left jugular, peripheral end, 25 cc. of blood,
rather dark .... A'
The animal, whose eyes are covered, remains perfectly quiet.
3:07; 22 respirations; pulse, 100.
3:10; Drew 25 cc. of blood from the carotid, almost as red as
A .... B
3:15; Took sample of air from the bag . . . . b
3:20; Drew 25 cc. of venous blood . . . . B'
4: 10; Drew 25 cc. of arterial blood, dark . . . . C
4:15; Took air from the bag . . . . c
The animal suddenly makes a violent effort and pulls off the
rubber bag for an instant (takes one inspiration of outer air) ; con-
tinued efforts and considerable panting.
4:22; 25 cc. of very dark venous blood . . . . C
4:30; pulse, 60; 18 deep respirations.
4:38; dies; a few very weak heart beats. Drew arterial blood,
very dark . . . . D
Took air from the bag . . . . d
Summary of the Experiment
Cor-
spond-
Arterial
Venous
Diff . in
Airs
mg
Pres-
sure
Bloods
Blood
O, | COo
o2 | co2
oa
Normal
76
AA'
21.6 | 45.0
12.4 | 46.8
9.2
b (11.5 of 02; 2.0 of C02)
41.8
BB'
19.6 | 42.7
10.2 | 49.1
9.4
c (4.7 of 02; 2.1 of C02)
1 17.1
I CC*
8.8 | 34.4
2.2 I 36.5
6.6
Lethal d (2.7 of 02;
1
1.9 of C02)
1 9.8
D
0.4 | 23.6
Gases of the Blood
637
Experiment CXCI. October 15. Female dog weighing 13 kilos.
Breathing free air; respirations, 20; pulse, 148; rectal temperature,
39.8°.
2:50; Drew 25 cc. of blood from peripheral end of jugular vein. A'
2:55; 25 cc. from carotid artery .... A
3 o'clock; Forced to breathe from a rubber bag containing 130
liters of air, through the double potash valves; the animal is very
calm although it struggled considerably at the beginning of the
experiment.
4 o'clock; 25 cc. of arterial blood . . . . B
4:12; 16 respirations; pulse, 86; temperature, 37.4°.
4:15; 25 cc. of venous blood . . . B'
Air from the bag . . . . b
Animal very quiet.
5:15; 25 cc. of venous blood . . . . C
Air from the bag . . . . c
Respirations, 16; pulse, 92; temperature, 36°.
6:10; 25 cc. of venous blood . . . . D'
Air from the bag . . . . d
Respirations, 16; pulse, 96; temperature, 35.5°.
7:10; 25 cc. of arterial blood . . . . E
25 cc. of venous blood . . . . E'
Air from the bag . . . . e
Respirations, 16; pulse, 100; temperature, 35.1°.
Death comes at 8:45; temperature 33°.
An accident prevents making an analysis of the blood.
The air of the bag contains per 100 O 4.9; CO; 1.2.
Summary of the Experiment
■ w>?>
m
<u
Airs
fed
Arterial
Venous
S C
1 <u
Bloods
Blood
Blood
J.gM
H
O 0 U
s &
V «
O &a
H %
O., 1 CO,
o.. i co2
Q O
Normal | 76 | AA'
22.2 | 29.4
17.2 | 40.3
I 5.0
39.8°
b (16.3 of 02 1.7 of C02) _| 59 | BB'
16.9 1 39.0
12.8 1 39.2
1 4.1
37.4°
c (13.6 of 02; 2.4 of CO,>) _| 49 | C
' '
11.3 I 43.0
36.0°
d (10.6 of 02; 3.1 of C02)| 38 | D'
1
8.8 | 45.8
I —
35.5°
e (7.7 of 02; 3.0 of CO.>) | 28 | EE'
10.2 | 34.5
6.0 1 45.8
1 4.2
35.1°
Lethal (4.9 of Os; 1.2 of CO>)| 17 |
1
1
33.0°
Experiment CXCII. November 13. Dog weighing 16 kilos. Breath-
ing free air; temperature 38.5°.
2:45; Took 30 cc. of carotid blood .... A
2:54; Took 30 cc. of blood from the peripheral end of the jugular
vein .... A'
2:56; We begin to force the dog to breathe from the bag containing
130 liters of air through the potash valves.
3:40; Rectal temperature 38°.
3:53; The animal is much hampered in its breathing, and has been
struggling for a few minutes. Took 30 cc. of venous blood . . . . B'
4:05; Took 30 cc. of arterial blood . . . . B
Air from the bag . . . . b
4: 15; Rectal temperature 36°.
638
Experiments
5 o'clock; Took 30 cc. of venous blood . . .
5:07; Took 30 cc. of arterial blood . . . . <
Air from the bag . . . . c
5:15; Rectal temperature 34°.
5:20; Arterial blood, 30 cc; animal dying .
5:30; Venous blood, animal dead . . . . D'
C
Summary
of Experiment
Airs
■ be <u
°o £
cm.
Bloods
Arterial
Blood
o, i co2
Venous
o5 i co2
<u
C e
a ft
P o
l 4)
iNormai
b (10.3 of O,; 0.3 of CO,.)
c (4.7 of O ; 0.3 of CO.)
At death
76 1 AA'
38 | BB'
17 | CC
— | DD'
18.0 I 49.0 | 14.7 | 54.0
6.0 1 42.3 1 4.7 1 49.0
3.7 1 29.7 1 2.8 | 37.0
0.33 I 24.0 | 0.15 | 28.7
3.3
1.3
0.9
0.18
38°
36°
34°
Figure 40 makes it still easier to comprehend the results of
these three experiments in regard to the variation of the gases of
the blood; as usual, the quantities of gas are plotted on the vertical
axis, the oxygen content and the barometric pressure which cor-
responds to it are plotted on the axis of the x's. The results of
Experiment CXC are marked by dotted lines ; those of
Experiment CXCI by dashes ; those of Experiment CXCII
by dashes and dots — . — . — . — .
We see at first glance that in both the venous and the arterial
blood the oxygen and the carbonic acid diminish when the tension
of the oxygen breathed diminishes.
We see also that the difference in gaseous content between the
arterial and the venous blood remains almost constant until the
oxygen in the air is about half exhausted, that is, in the neighbor-
hood of a half-atmosphere. Beyond that, the graphs draw closer
together.
So, up to a certain degree, the venous blood loses oxygen in the
same quantity as the arterial blood; that deserves some attention.
Let us take, for example, Experiment CXC. At the beginning,
the arterial blood contains 21.6 of 02; the venous blood, 12.4; differ-
ence, 9.2; which means that the tissues needed for their regular
maintenance and consumed as it passed 9.2 volumes of oxygen for
each 100 volumes of blood.
We drop to a pressure of 41.8 cm., and on account of the de-
creased capacity of the blood for oxygen at this pressure (See below
in Subchapter V) there is now only 19.6 of this gas in the arterial
blood; we find only 10.2 in the venous blood: difference, 9.4. The
consumption of oxygen by the tissues has then remained the same,
Gases of the Blood 639
in spite of the decrease in the proportion of 02 in the blood, and we
understand that the animal finds no serious trouble in its different
functions: respiration, circulation, etc., as the detailed report of
the experiment shows.
But we continue the decompression; the pressure now is only
17 cm., and in the arterial blood there are only 8.8 volumes of oxy-
Fig. 40— Decrease of the gases of the arterial blood and the venous blood
when the tension of the oxygen breathed decreases; the lower
group corresponds to the oxygen of the blood, the upper to the
carbonic acid.
640 Experiments
gen. Quite evidently, the oxygen consumption by the tissues
could not have remained at the same value, which we have seen
to be above 9; now the analysis of the venous blood shows that it
dropped to 6.6, that is, that there still remains in the venous blood
2.2 volumes of oxygen, which the tissues cannot easily extract.
From this, there result for the animal evident metabolic disturb-
ances, a lowering of temperature, a general depression of the
muscles, particularly the heart, which adds still more to the dis-
tressing effect, lessening the oxygen consumption by lessening the
circulatory activity.
The increasing difficulty of the dissociation of the oxy-hemo-
globin of the venous blood when its proportion of oxygen is les-
sened considerably seems to be the cause of the distress of the ani-
mal, which can no longer extract from its blood the quantity of
oxygen necessary for its metabolic equilibrium in a given tem-
perature. Now, the proportional quantity of oxygen consumed by
animals varies greatly from one individual to another, as, for ex-
ample, is shown by Experiment CXC, in which it is 9.2, compared
to Experiment CXCII, in which it is 3.3. Furthermore, the absolute
quantity of oxygen contained in a given volume of blood varies
decidedly also, as we have learned from the numerous analyses
already reported. Finally, the quantity of the blood itself likewise
appears very variable. It is not at all surprising then that the be-
havior of different individuals of the same species and even more
of representatives of different species should be very variable under
the effect of the same decompression, one being much affected while
the other experiences almost no effect. One can easily grasp this
idea by assuming two animals in which two of these three condi-
tions are identical and the third very different; it is useless to con-
tinue with this reasoning because we perceive a series of combina-
tions whose effect makes the problem very complex and makes it
impossible to predict the outcome with certainty.
We shall refer again to these facts in the third part of this book
when we come to the explanation of the symptoms known by the
names of balloon sickness and mountain sickness.
Gases of the Blood 641
Subchapter V
THE QUANTITY OF OXYGEN WHICH CAN BE
ABSORBED AT DIFFERENT BAROMETRIC PRESSURES
BY THE BLOOD DRAWN FROM THE VESSELS
The analyses of the gases contained in the blood of living ani-
mals subjected to pressures lower than one atmosphere gave me
for oxygen, as I remarked before, results far different from the con-
clusions which could have been drawn from classic researches,
particularly those of M. Fernet.
Magnus had already shown that when blood is placed under the
belljar of the pneumatic machine and the pressure is gradually
diminished, gases begin to escape only at very low pressures, and
the blood turns dark (that is, loses a considerable part of its oxy-
gen) only in the neighborhood of 10 cm. of mercury.
M. Fernet had intended, as we saw in the historical part of this
book, to find out whether the gases of the blood were in a state of
simple solution or bound in a chemical combination. In the first
case, he said with reason, the capacity of the blood for these gases
should be proportional to the barometric pressure, following the
well-known Law of Dalton. In the second, there will be no relation
between this law and the proportion absorbed at different pres-
sures. And if a gas is partly dissolved and partly combined in this
liquid, it will be possible, by a simple calculation, to determine the
proportional value of these two parts.
Now,— speaking only of oxygen— by agitating blood in contact
with this gas under pressures varying from normal pressure to 647
mm., M. Fernet reached this double conclusion: 1) that there is
dissolved in the blood plasma a quantity of oxygen (coefficient of
solubility at 16°, that is, volume of gas dissolved per unit of volume
of liquid under normal pressure: 0.0288) nearly equal to that which
is dissolved in pure water (coefficient of solubility at 16°, according
to Bunsen: 0.0295) ; 2) that the blood corpuscles combine chemically
with a quantity of oxygen, independent of the pressure, much
greater than the preceding, because it is on the average 0.0958 per
unit of volume of blood. We see then that, according to these ex-
periments, the barometric pressure, in these various modifications,
can hardly modify the proportion of oxygen contained in the blood.
In fact, it could act only on the simply dissolved gas, which is to the
combined gas in the proportion of 0.0288 to 0.0958, that is, of 1 to 3.3,
when the absorption experiments are performed with pure oxygen.
642 Experiments
Now, as M. Fernet remarks, since the respirable air contains only
one-fifth of oxygen, the proportion dissolved in the serum must be
diminished in the same proportion; whence it results that in the
blood the proportion chemically combined independent of the
pressure will be 3.3 x 5 = 16.5 times greater than that which follows
the changes of the barometric column. And therefore, he con-
cludes, "the absorption of oxygen is very nearly the same, whatever
the atmospheric pressure, on mountain tops and in the plains."
To this conclusion, which considered only the quantity of oxy-
gen absorbed by an animal in a given time under different pres-
sures, and which agreed with facts previously noted by Regnault
and Reiset, Vierordt and Lehmann, the physiologists have added a
second, — which seems wholly justified, a priori, by the very re-
searches of M. Fernet, — namely, that in the blood of the living ani-
mal, the quantities of oxygen are almost independent of the baro-
metric pressure. "Otherwise," says Longet,9 for example, "we
would reach this conclusion, that the blood of inhabitants of regions
where the atmospheric pressure is half the normal would contain
only half as much oxygen as the blood of those dwelling at sea
level, where the pressure is 0.760 meters. How can we believe that
observers would not have been struck by the profound modifica-
tions which such variations would not fail to produce in the manner
of existence of these populations?"
This conclusion and the reasoning on which it is based were ac-
cepted by all the physiologists. It is very interesting to note that
when M. Jourdanet stated, basing his assertions on a long medical
practice, that in the lofty regions of the Mexican Republic, "the
mode of existence of the population is profoundly modified," the
very argument of Longet was turned against him, and the exact-
ness of his observations was denied as contrary to the data of
physiological chemistry.
The explanation given by M. Jourdanet of the special patho-
logical state which he had noted on the plateaux of Anahuac was
entirely based upon the lessened absolute quantity of oxygen con-
tained by the blood of men and animals under so low a pressure.
Now we have just seen in the first subchapter that he was abso-
lutely right, and that, in spite of the natural astonishment of Longet.
it is correct to say that if one lowers the barometric pressure one
half, the oxygen content of the blood will be reduced almost one
half.
There was then, between the result of M. Jourdanet's observa-
tions and our experiments on the one hand, and the logical conclu-
Gases of the Blood 643
sions from the analyses of M. Fernet on the other, a contradiction
which could be only apparent, and which demanded explanation.
But in the first place, M. Fernet could change the pressure only
in very narrow limits; for whole blood, the pressures had varied
from 741 to 580 millimeters. I should inquire what would happen
in experiments in which the pressure was diminished to the neigh-
borhood of a vacuum on the one hand, and increased several
atmospheres on the other.
The problem was infinitely easier to solve than in the time of
M. Fernet; in fact, I had at my disposal means of extracting all the
gases of the blood, which the physicist had not been able to obtain,
in spite of all his efforts. He therefore had had to use direct meas-
urement of the gases absorbed, that is, measuring the decrease in
volume of gases agitated with blood which had previously been
deprived of those which it contained at first; a series of very deli-
cate operations, which required a very complicated set of tools, and
the use of glass apparatus which would not permit high pressures.
On the contrary, thanks to the mercury pump, after agitating the
blood in a large quantity of air, under determined pressures, I
could extract the dissolved gases easily and completely. I could
thus make a large number of analyses, which, without claiming the
exactness of second decimals, are quite accurate enough to reach
the goal I had set for myself.
I shall report some of them; but I must first thank M. Grehan'c,
who was then taking my place on the Faculte des Sciences of Paris,
and who, at my request, consented to carry out a great number of
them.
1. Pressures Lower Than One Atmosphere.
My first experiments were simply made by placing in a flask
with a wide mouth (Fig. 41) a certain quantity of defibrinated
blood which I then agitated vigorously, without completely closing
the flask. When the blood was thus saturated with oxygen, I fast-
ened the flask to the end of a long cord and whirled it like a sling,
which procedure brought out very rapidly the air bubbles which
had remained suspended in the viscous liquid. I then took with a
graduated syringe a certain quantity of blood, from which I ex-
tracted the gases by the mercury pump.
The mouth of the flask was then carefully closed by a rubber
stopper through which passed a thermometer and two glass elbow
tubes. One of these tubes dipped into the blood, so that one could
obtain samples of the blood through it by means of cock R. Cock R'
644
Experiments
of the second tube led to a forked piece through which at the same
time communication was made in a with the pneumatic machine
and in b with a tube dipping into a reservoir full of mercury, which
tube formed a barometer.
Fig. 41 — Flask arranged for the saturation of blood by oxygen at different
decompressions.
With my set-up thus arranged, I lowered the pressure to the
desired point, closed cock R', took off the forked tube, and shook
the flask vigorously for a quarter of an hour. Under these con-
Gases of the Blood
645
ditions, the oxygen which would have been present in excess be-
cause of the reduced pressure could escape from the blood, which
was supersaturated at this new pressure. The flask was large
enough in proportion to the quantity of blood, so that the oxygen
thus set free was absolutely negligible. Furthermore, I made sure
by a simple procedure that the pressure had not varied perceptibly
during the agitation.
Fig. 42 — Water motor shaking the flask containing the blood to be satu-
rated with oxygen.
When this was done, I took a new sample of the blood for
analysis of the gases.
Since I placed in the flask about 200 cc. of blood, it was possible
for me to make several analyses with the same blood at different
pressures.
Later, a useful improvement was added to this method, whose
principal cause of error lies in the difficulty of shaking hard enough
with the hand. The flask was firmly fixed on a plank which was
vigorously moved by a little water motor (Fig. 42). Under these
conditions, the saturation of the blood was accomplished with great
rapidity, and a few whirls of the sling were enough to dispel the
froth and the bubbles of gas in suspension.
646 EXPERIMENTS
And now we come to the experiments.
Experiment CXCIII. December 1. Flask of 3 liters; 180 cc. of
defibrinated dog blood.
After agitation at normal pressure, the blood contains per 100
cc. of liquid: oxygen, 19.0; carbonic acid, 35.2.
After agitation at a pressure of 56 cm.: O, 17.2; CO, 28.4; N 2.4.
At 36 cm.: O* 16; CO 27.6; N 1.6.
At 6 cm.: O 12.4; CO* 23.2; N 1.0.
Experiment CXCIV. January 7. Dog blood, agitated at 76 cm.,
containing per 100 cc. of liquid: oxygen, 25.3; carbonic acid, 35.7; nitro-
gen, 2.3.
Agitated at a pressure of 38 cm., still contained O* 23.4; CO* 27.5;
N 1.4.
Experiment CXCV. January 9. Blood of sick, weak dog.
CO*
Shaken at 75 cm., contains: O. 12.3; CO, 41.6; N 2.4. = 3.4.
O*
CO*
Shaken at 34 cm., contains: O. 11.3; CO, 41; N 1.4. = 3.6.
O*
CO*
Shaken at 18 cm.: O, 10.4; CO, 35.6; N 0.9. = 3.4
O*
CO*
Shaken at 12 cm.: O. 10; CO, 28.7; N 0.6. = 2.8
O*
Experiment CXCV I. January 15. Dog blood.
CO*
Shaken at 77 cm., contains O* 20.2; CO* 28.4; N 2.4.— =1.40.
O*
CO*
Shaken at 34 cm., contains O., 18.9; CO, 24.9; N 1.3. =1.31.
O*
CO*
Shaken at 6 cm., contains O, 17.7; CO, 19.8; N 0.4. =1.12.
O*
Experiment CXCVII. January 21. Ox blood.
Shaken at 770 mm., contains: O, 19.3.
Shaken at 83 mm., contains: O, 18.5.
Shaken at 22 mm., contains: O, 13.3.
Experiment CXCVIII. February 2. Blood of a dog subjected for
several days to repeated hemorrhages and having on its thigh a large
festering sore.
The blood was agitated twice; in one case, the temperature was
that of the laboratory, 11.4°; in the other, the flask and the plank
Gases of the Blood 647
were submerged in water at 37° long enough for a temperature
equilibrium to be established.
1.) Temperature, 11.4°.
At 760 mm., the blood contains O. 8.1; C02 27.6; N 2.0.
At 9 mm., the blood contains O 5.1; CO 17.5; N 0.1.
2.) Temperature, 37°.
At 760 mm., O 7.9; CO 23.9; N 1.2.
At 407 mm., O 7.1; CO 22.4; N 0.8.
Experiment CXCIX. March 6. Large hunting dog, in good
health; 500 gm. of blood drawn from the carotid, shaken in the air,
and filtered through linen. Flask of 2 liters.
Shaken for a half hour at the pressure of 775 mm. (762 mm.
after a deduction of the tension of the water vapor) and at the tem-
perature of 15.5°, the blood contained: 02 23.2; CO, 30.2; N 2.4.
CO
= 1.30.
O2
CO
At 349 mm.: Oa 22.6; CO 27.4; N 1.0. =1.21.
O
CO
At 167 mm.: O 21.5; CO 25.1; N 0.6. =1.12.
O
CO
At 88 mm.: O 20.0; CO 21.0; N 0.4. =1.05.
O
Experiment CC. March 12. Dog blood; temperature 12°. Flask of
4.330 liters.
Shaken at 749 mm. (deduction made of the water vapor tension
CO
at 12°) contains: Oxygen 23.1; CO, 27.5; N 2.6. =1.18.
O
CO=
At 361 mm.: O 23.0; CO 22.0; N 2.0. = 0.95.
O^
CO2
At 99 mm.: O 22.3; CO. 18.9; N 0.3. = 0.84.
O?
CO^
At 53 mm.: O 20.8; CO 15.4; N 0.2. = 0.74.
o>
Experiment CCI. May 29. Dog blood; temperature 24°; flask of
4.330 liters.
648 Experiments
At 738 mm. (deduction of the water vapor tension), the blood
CO
contains: Oxygen 25.6; CO, 23.0; N 2.6. = 0.89.
O
CO
At 318 mm.: 02 23.7; C02 18.9; N 1.8. = 0.79.
O
CO
At 128 mm.: O. 23.0; C02 16.2; N 0.5. = 0.70.
O
CO
At 78 mm.: 02 23.0; CO* 13.7; N 0.5. = 0.59.
O*
co2
At 38 mm.: O, 19.3; CO, 10.8; N 0.3. = 0.55.
o2
The accompanying graph (Fig. 43, A) summarizes and ex-
presses the average of the results of the preceding experiments, in
Fig. 43— Capacity of the blood for absorbing oxygen at pressures below
one atmosphere. A. Laboratory temperature. B. Body tempera-
ture. C. Living animals.
Gases of the Blood 649
everything relating to oxygen. It was obtained by assuming that
the initial proportion of oxygen at normal pressure was always 20
volumes per 100 volumes of blood, and by determining the value of
the other numbers by proportions like the following, which applies
to Experiment CXCIII: 19 (normal pressure) : 20 = 17.2 (pressure
of 56 cm.) : x = 18.1.
A simple glance will show that, from normal pressure to that of
10 to 15 centimeters of mercury, the blood absorbs quantities of
oxygen that are almost the same; one or two volumes less, and that
is all. It is even very possible that this difference affects only the
oxygen dissolved in the plasma, which rises, according to M. Fernet,
to 2.88 per 100 volumes of liquid. So our analyses, which go to pres-
sures considerably lower than those used by M. Fernet, give results
which tend in the direction of the conclusions of this physicist.
But from 15 centimeters of mercury on, the oxygen escapes from
the blood in a far greater proportion than the Law of Dalton would
require. There occurs a dissociation of the combination of the
oxygen with the hemoglobin, a dissociation whose intensity in-
creases rapidly.
I have made a sort of control experiment using a method nearer
that of M. Fernet, since instead of extracting the oxygen progres-
sively by agitation at lower and lower pressures, I measured the
quantity absorbed by blood that had previously been entirely de-
prived of gas.
Here are the results of three experiments carried out in this
way. It will be seen that they agree, in their general trend, with
those obtained by the first method.
Experiment CCII. December 30; pressure 762 mm.
We prepare two mercury pumps and two apparatuses for extract-
ing the gases of the blood, in which absolute vacuum is made.
From the jugular vein of a dog by means of a syringe 138 cc. of
blood is drawn, and this blood is injected into a flask full of air; the
blood is defibrinated and oxygenated by long shaking in the flask.
89.5 cc. of blood measured in a graduated test tube is passed into one
of the pumps; this blood has been filtered through linen and freed of
fibrin and air bubbles; the gases are extracted from the blood heated
to a temperature of 35° to 39°, until a dull click is heard; the blood
is completely reduced. When the extraction has been made, the blood
is cooled in cold water to about 10°.
The analysis of the gases extracted shows that 100 cc. of blood
shaken in the air at a pressure of one atmosphere has absorbed 19.8
cc. of oxygen.
Air at a pressure of a half atmosphere is admitted to the empty
apparatus; to do this, a long vertical tube, T (Fig. 44) is used, into
650
Experiments
which mercury is poured; it is closed by a stopper with two holes,
through which two glass tubes pass. One, a, is dipped into the mercury
to a depth of 381 mm., half of 762 mm.; it opens into the air and has
a cock r. The second tube, b, which reaches merely to the upper part
of the tube full of mercury, curves outside into a siphon which is
joined by a rubber tube, c, to the central tube which projects from the
middle of the little mercury basin C which tops the cock R of the gas
Fig. 44 — Apparatus to bring blood into contact with the air at a specified
decrease in pressure.
pump; when this cock is turned as the figure shows, and cock r is
opened carefully, the outer air is admitted bubble by bubble through
the mercury, and when the air which has come in contact with the
blood has a pressure equal to a half atmosphere, the outer air ceases to
enter through tube a.
The blood then is agitated by raising and lowering the balloon of
the extraction apparatus, and the agitation is made 25 times with air
and with mercury; the blood becomes a very bright red.
Gases of the Blood 651
By working the pump and holding the balloon containing the
blood above the horizon, the blood is made to pass into the barometric
chamber and then into a syringe. In this way 69 cc. are obtained
which are introduced into the second mercury pump. The extraction
of the gases gives 14.5 cc. of oxygen; that is, per 100 volumes and
after corrections, 19.8, exactly like the preceding.
So the blood absorbs exactly the same quantity of oxygen in both
cases.
Experiment CCIII. December 31.
100 cc. of dog blood absorbed at the ordinary pressure of 760 mm.
32.4 cc. of oxygen. 100 cc. of the same blood, first deprived entirely of
gas, absorbed under the pressure of 24 mm., that is, at a pressure 32
times less, 26.1 cc. of oxygen.
Experiment CCIV. March 20 and 21. From a branch of the femoral
artery of a terrier in good health 500 gm. of blood were taken and
defibrinated by agitation in a flask.
In a large flask whose interior volume is equal to 4.335 liters, a
vacuum is made by means of the pneumatic machine; next, the air
is extracted by a mercury pump so as to bring the pressure of the
remaining air to about 2 centimeters; 68 cc. of blood completely freed
of gas by means of a mercury pump at 40° are injected into the flask
by means of a syringe, and the blood is shaken with the rarefied air
for a half hour by the hydraulic motor. After the agitation, the
pressure of the rarefied atmosphere is measured and the ascertained
pressure of the water vapor tension at the temperature of the labora-
tory air is deducted, so as to obtain the pressure of the air assumed
to be dry; it is only 152 mm. The gases are extracted from the blood
agitated with the air under this low pressure by passing the blood
directly from the flask into an evacuated gas pump (the flask being
weighed before and after).
2.) By means of a syringe, 68 cc. of blood freed of gas and 68 cc.
of air are injected into the flask; agitation for a half hour, etc
In the following experiments, each time in the same way, 68 cc. of
blood and 68 cc. of air are injected. Here are the results obtained
after the necessary corrections:
100 gm. of blood first freed of gases
At the pressure of 15 cm. absorbed 7.3 cc. of oxygen.
At the pressure of 29 cm. absorbed 9.9 cc. of oxygen.
At the pressure of 40 cm. absorbed 12.3 cc. of oxygen
At the pressure of 51 cm. absorbed 13.2 cc. of oxygen.
At the pressure of 75.6 cm. absorbed 18.5 cc. of oxygen.
We conclude then from these data that down to low pressures
the contradiction noted between experiments made in vitro on the
capacity of blood for oxygen and the analyses of the blood of living
animals exists entirely as it appeared to us at first. At all pressures,
the blood, agitated in a flask, contains an almost equal quantity of
oxygen (graph A of Fig. 43) , whereas in the living animal the pro-
652 Experiments
portion of oxygen diminishes rapidly, as is shown by graph C,
which reproduces graph Ox of Figure 31, and the analyses sum-
marized in Table X.
Considering this difficulty, I asked myself whether the high tem-
perature of the animal's body could not cause some changes in the
results I obtained at low temperatures. We knew already that to
extract the oxygen of the blood completely we must add to the
action of the vacuum that of a rather high temperature. I will
report here an experiment which demonstrates this truth.
Experiment CCV. June 24. 65 cc. of defibrinated dog blood are
placed at 4 o'clock in the receiver of a pump for the extraction of
gases, in which an absolute vacuum had previously been made. The
temperature is only 19°.
The blood is shaken repeatedly in the balloon and all the gas
which will come out is extracted, but without warming it. We obtain
thus, per 100 cc. of liquid, 11.2 cc. of oxygen, 20.0 cc. of carbonic acid,
and 2.0 cc. of nitrogen.
This procedure is repeated until 6 o'clock; no more gas has come
after several pump strokes, and the blood has remained bright red.
The double-boiler is heated to the boiling point, and then, with a
single pump stroke, the rest of the gas is extracted; the blood turns
dark immediately. The quantity just extracted represents, per 100 cc.
of blood: Oxygen 13.2; CO 13.0; N 0.6.
So the blood contained in all: O* 24.4 cc; CO 33.0; N 2.6.
If this blood had been subjected to the experiments performed
by the method previously described, and if a complete vacuum had
been made in the agitation flask, at 19°, 13.2 cc. of oxygen could
have still been extracted by the heat. Temperature has, therefore,
a great importance.
And so I set up the experiment in a slightly different manner.
The agitation flask, instead of being fastened on the plank of
Figure 42, was solidly fastened underneath at a certain distance, so
as to dip into a bath of lukewarm water whose temperature was
kept at a fairly constant degree all through the agitation.
Here are the results of experiments made under these conditions.
Experiment CCV I. June 3. Dog blood; shaken for xk hour, the
flask of 4.330 liters being submerged in water at 40°.
At 725 mm. (deduction of water vapor tension) it contains: Os 15.4
At 280 mm.: 02 13.8.
At 100 mm.: Oa 8.5.
Experiment CCVII. July 10. Dog blood; shaken for 20 minutes, the
flask of 4.330 liters being submerged in water at 40°.
At 738 mm. (with the usual deduction), the blood contains:
Q2 20.1; CO, 18.8; N 1.5.
Gases of the Blood 653
At 290 mm.: 02 16.4; C02 13.0; N 0.6.
At 87 mm.: O* 11.3; CO 8.6; N 0.4.
At 26 mm.: CK> 7.2; CO* 7.0; N 0.2.
Experiment CCVIII. February 18. Defibrinated dog blood, interior
temperature of the flask 38°. Agitation at normal pressure; blood con-
tains O2 20.2.
At 38 cm.: 02 17.7.
At 19 cm.: 0» 16.4.
Experiment CCIX. February 26. Defibrinated dog bleod. Agita-
tion at normal pressure; interior temperature of the flask 38°; the
blood contains 02 18.2; C02 10.1.
At 38 cm.: 02 14.8; C02 6.8.
At 19 cm.: 02 10.6; C02 7.0.
These four experiments, when we get the averages, setting the
origins of the graphs at 20, give us graph B of Figure 43.
We see that the curve B dips much more rapidly than the
preceding A, and more nearly approaches the one which, taken
from Column 8 of Table X, expresses the oxygen changes in the
living animal, and is represented here in C. In other words, the
contradiction noted loses much importance when we supply the
temperature conditions given by the bodies of warm-blooded
animals.
However, our analyses show that the arterial blood of a living
animal subjected, for example, to a half atmosphere, could absorb
a quantity of oxygen much greater than that which it really
contains.
That is because the intra-pulmonary agitation of the blood with
the air is no longer carried on in satisfactory conditions. Even at
normal pressure, as we have seen, the arterial blood is not saturated
with the oxygen which it can hold; it reaches that point of satura-
tion— or nearly so— only after exaggerated respiratory efforts,
which bring on an exaggeration of circulatory rapidity. At a half
atmosphere, to obtain the same result as at ground level, the activity
of intra-pulmonary mixing would have to be doubled; the respira-
tory movements must be doubled in amplitude and rapidity; the
heart movements must be doubled in strength and number. That
is evidently impossible.
Summarizing, the conclusions of M. Fernet's work are legitimate
only under the conditions of pressure and temperature (16°) at
which he worked. At lower pressures, at body temperature, the
part of the oxygen which he considers as chemically combined in
the blood because it is independent of the pressure, really follows
the pressure changes, although considerably less quickly than a
654
Experiments
gas in simple solution would do. But in the living organism, this
is complicated by an insufficient agitation of the blood in contact
with the air, and so there results a much more rapid decrease of
the oxygen of the blood than ex-
periments in vitro would lead one
to think.
2. Increased Pressure.
To study the absorption of oxy-
gen by the blood at pressures
greater than one atmosphere, I had
made a bronze receiver, of a ca-
pacity of 175 cc, capable of resist-
ing 25 atmospheres easily. (Fig.
45.) The procedure was very
simple. In the apparatus, whose
lower part could be unscrewed,
was placed the defibrinated blood
to be analyzed; I used about 100
cc. of it. Then, after the cylinder
had been closed, I compressed the
air by screwing on the compres-
sion pump, and closed cock R when
the manometer indicated that the
desired pressure had been reached.
I next agitated the apparatus by
fastening it on the plank of Fig-
ure 42. Finally, to extract the blood
into the graduated syringe, I had
only to fit its extremity to the
capillary cock r, which I half-
opened; the air pressure immedi-
ately drove the blood out; a few
strokes of the pump kept a con-
stant pressure in the apparatus
while the blood was being taken
out. When I was dealing with
very high pressures, when nitro-
gen dissolved in quantity was
given off in the syringe, I substi-
tuted weight for volumetric mea-
sure, since the froth did not per-
mit me to determine volume
exactly.
When I wished to make an analysis
at a certain compression, I began by supersaturating the blood by
Fig. 45 — Apparatus to saturate
blood with air at high pres-
sures. R. Large cock by which
compression is made. r. Capil-
lary cock by which blood sam-
ples are taken.
Gases of the Blood 655
shaking it at a higher pressure, so as to be sure, when I had brought
it to the desired pressure, that it really contained all the oxygen it
could absorb. If several analyses at different pressures were to be
made of the same blood, I followed the same procedure, beginning
with the highest; this was quite legitimate, because the quantity of
oxygen introduced into the apparatus under compression was al-
ways much greater than the blood could absorb. The pressure re-
corded in the experiment was the one read after the agitation and
the absorption had been finished.
An important point was first determined: namely, that the in-
crease of the oxygen contained in the blood was quite temporary
and disappeared rapidly when the compression was over. The
following experiment proved this.
Experiment CCX. June 20. Defibrinated dog blood.
At normal pressure, after long agitation, contains O 20.0.
100 cc. were put into the apparatus, and the compression was
carried to 12 atmospheres, with superoxygenated gas, so that the
oxygen tension corresponded to 44 atmospheres of air. After an agita-
tion which was insufficient for complete saturation, the blood con-
tained, per 100 cc: 02 37.7.
I then placed in a flask the rest of the compressed blood, which
was very red and contained much gas in suspension; the flask was
whirled like a sling once, and 10 minutes after being taken from the
apparatus, the blood contained only 20 vol. of oxygen, as at the
beginning of the experiment.
We now come to the experiments carried on with care that the
saturation should be complete; the pressure was made with ordi-
nary air.
Experiment CCXI. June 20. Defibrinated dog blood.
At normal pressure contained Oa 20.0.
At 12 atmospheres contained 0-> 30.0.
At 8 atmospheres contained O 25.7.
At 4 atmospheres contained O- 22.8.
Experiment CCXII. January 22. Defibrinated dog blood.
At normal pressure contained O 20.2.
At 18 atmospheres contained O- 28.2.
At 9 atmospheres contained O- 25.9.
I particularly call attention to the following experiment, which
was carried out with the greatest precautions.
Experiment CCXIII. January 12. 500 cc. of blood taken from the
femoral artery of a very large dog. This blood is defibrinated, filtered
through linen, then shaken for a half hour with air at normal pres-
sure; it contains 14.9 volumes of oxygen.
It is then placed in the apparatus; for each experiment, the agita-
tion lasts a half hour. The findings were:
At 6 atmospheres, Os 19.2.
At 12 atmospheres, O 26.0.
At 18 atmospheres, O* 31.1.
656
Experiments
Let us discuss the results of this last experiment.
Let us call x the volume of supposed oxygen combined with
the hemoglobin contained in 100 cc. of blood, a volume which, by
hypothesis, would be independent of the pressure; let us call y the
volume of oxygen which 100 cc. of blood would absorb in a state
of simple solution as a result of agitation in the air at normal
pressure; we shall have:
At 1 atmosphere x + y = 14.9 (1)
At 6 atmospheres x + 6y = 19.2 (2)
At 12 atmospheres x -f 12y = 26.0 (3)
At 18 atmospheres x + 18y = 31.1 (4)
Let us subtract (1) from (4), and we get 17y = 16.2; whence
y = 0.95; from the equation (1) we then get x = 14.9 — 0.95 = 13.95.
Substituting these values in equations (2) and (3), we find
the figures 19.6 and 25.4, instead of 19.2 and 26, differences which
are quite in the order of experimental errors.
:^H
I
■-;-'■
•
1
-
■
I
■
- mm • -; ■
Fig. 46 — Capacity of the blood for oxygen, from a vacuum up to 18 atmos-
pheres of air.
Gases of the Blood 657
So the hypothesis is verified, and above 1 atmosphere, the
pressure adds to the blood only the oxygen dissolved, whose in-
creasing proportion follows Dalton's Law.
If then we take 20 as average proportion of oxygen contained
in the blood at normal pressure, and if we assume, to make the
calculation easy, that there is one volume dissolved, we shall find
that at 6 atmospheres there will be 25 volumes; at 12 atmospheres,
31 volumes; at 18 atmospheres, 37 volumes.
These last results are marked on the graph of Figure 46 by
points whose series naturally forms an absolutely straight line.
Now if we had drawn on the same scale the graph of Experiment
CCXIII and had then traced back the whole to its point of origin
(14.9) on the line marked 20, the four points of this graph would
be represented by the little crosses on the graph. We see how
close they are to the theoretical points.
There has been added between 1 atmosphere and vacuum a
reduction of graph A of Figure 43, which completes the survey of
the capacity of blood for oxygen, from the lowest to the highest
pressures.
The question arose whether for high pressures the temperature
would cause any important difference in the capacity of the blood
for oxygen. Since the experiments which I have just reported
were carried on at the temperature of the laboratory, I performed
another, shaking the blood in a bath kept at 40°. As the results
agreed with the preceding, I thought it unnecessary to gather more
data.
Here is the experiment.
Experiment CCXIV. January 15. 300 grams of arterial blood were
drawn from a large dog, and were defibrinated and filtered through
linen.
I placed 130 grams in the apparatus of Figure 31; I compressed
the air to 22 atmospheres, and agitated the blood and the air for a
half hour, the apparatus being submerged in water at 40°.
I lowered the pressure to 18 atmospheres, and 5 minutes after,
I removed 28 grams of blood .... A
The pressure being lowered immediately to 12 atmospheres, I
agitated the blood again and removed 33 grams . . . . B
A similar procedure gave me at 6 atmospheres 41 grams of blood.
. . . . C
Finally, at normal pressure, I had left 20 grams of blood . . . . D
The analysis by the pump showed that:
A (18 atmospheres) contains, per 100 volumes: O^ 35.7; N 19.2.
B (12 atmospheres) contains, per 100 volumes: O 30.9; N 15.1.
C (6 atmospheres) contains, per 100 volumes: O- 27.1; N 7.8.
D (1 atmosphere) contains, per 100 volumes: O^ 23.0; N 1.3.
658 Experiments
Using on these figures the calculations which have just been
applied to Experiment CCXIII, we find for the coefficient of the
oxygen dissolved 0.75 and for the values of B and C 31.2 and 26.7.
The difference between the calculation and the experiment is,
therefore, in the first decimals, and should not disturb us.
And so at body temperature, as at laboratory temperature, when
the pressure is increased, the increase in the oxygen proportion
follows Dalton's Law.
On the other hand, if we refer to what was observed directly
in the living animal (Fig. 36, solid line) , we see that the quantity
of oxygen contained in the blood is considerably less than its maxi-
mum capacity in vitro.
This is in part due to the fact that the oxygen in simple solutior
in the serum tends to penetrate also by simple solution into all tht
organic liquids and the tissues bathed by the blood, until an
equilibrium of solution is established between them and this
serum.
The slowing up of the respiratory movements and the circula-
tion of the blood, so easy to observe in cold-blooded animals at
high pressures, certainly is an added factor in the diminution of
the quantity of oxygen introduced into the blood, by modifying
the conditions of the air-blood agitation taking place in the lungs.
There would be, on the part of the organism, a struggle for
equilibrium, working inversely to that which we stressed above.
If we now refer to this observation already made several times
that the blood in the conditions of normal respiration is never satu-
rated with the oxygen that it can absorb, we shall perceive that
when the increase of pressure introduces a little more oxygen into
the blood, this oxygen will first be rapidly condensed by the blood
corpuscles, so that the hemoglobin of the blood is completely satu-
rated before a larger proportion remains in the serum.
But from the purely chemical point of view, the data which I
have just reported present a new interest when they are compared
with those recently obtained by MM. Risler and Schutzenberger.10
According to these chemists, the blood, or rather the hemoglobin,
from which all possible oxygen has been removed by the action
of the vacuum or of carbon monoxide, would still contain a quan-
tity almost equal to what it has just lost.
There would therefore be here a sort of protoxy-hemoglobin,
which the vacuum, even when aided by heat, and which the carbon
monoxide could not reduce, and a deutoxy-hemoglobin, from which
the vacuum and the carbon monoxide could take its second equiva-
lent of oxygen. Beyond that, the hemoglobin, completely saturated,
could take up no more oxygen, whose proportion would increase
Gases of the Blood 659
only by simple solution in the ambient serum. That strongly
recalls the mode of union of the carbonic acid with the alkaline
bases, whose protocarbonates are indecomposable by a vacuum,
whereas the deuto-carbonates at very low barometric pressures
lose their second equivalent of acid, as we have known since the
research of H. Rose. The whole blood then would behave towards
oxygen as a solution of bicarbonate of soda does towards carbonic
acid. In both cases, it is 1.) in solution in water and its proportion
there can be indefinitely increased according to Dalton's Law; 2.)
in union easily dissociated by a vacuum aided by heat; 3.) in union
unaffected by a vacuum and heat.
This resemblance is very striking if we note the manner in
which this gas leaves the blood when the blood is agitated with air
at different barometric pressures.
The agitation of blood with pure air, at normal pressure, very
slowly takes from it a part of its carbonic acid, without being able
to take it away altogether. If the air is expanded, the gas escapes
a little more quickly. However, the experiments which have just
been reported above show that, even at quite low pressures, the
blood does not lose its carbonic acid quickly. However, this gas
leaves the blood in slightly larger proportions than the oxygen;
C02
so we see the proportion lose value directly as the decompres-
o2
sion is increased (Exp. CXCIX, CC, and CCI) .
On the other hand, when I brought about a progressive vacuum
on blood placed in the mercury pump, I found that the acid left
the blood in considerable proportions only at very low pressures,
almost at the same time as the oxygen. In other words, the bicar-
bonates and the alkaline phospho-carbonates behave in the vicinity
of a vacuum like the deutoxy-hemoglobin of which I was speaking
a little while ago.
1 Note sur les analyses du ga? du sang; influence de I'eau.— Proceedings, vol. LXXIV,
p. 330; 1872. The memoir is published in full in the Journal de I'Anatomie et de la Phvsiologie,
vol. VIII, p. 187-200; 1872.
2 The numbers expressing the volumes of the blood gases have always been reduced to the
temperature of 0° and the pressure of 76 cm.
* Du siege des combustions respiratoires. Journal de I'Anatomie et de la Phvsiologie,
vol. II, p. 302-322; 1865.
4 Lecons, etc., p. 119.
5 Des gas du sang. Archives de Phvsiologie, vol. IV, p. 5-26, 190-203, 304-318, 447-469, 573-587,
HO -731; 1871.
• Lecons, etc., p. 130 et seq.
7 Lecons sur la physiologic de la respiration, p. 161.
s Comptes rcndus de la Societe de Biologie for 1871, p. 61.
»Trait6 de physioloqie, Third edition, vol. V, p. 592; 1868.
10 Comptes rendus de I'Academie des sciences, vol. LXXVI, p. 440; February, 1873.
Chapter III
PHENOMENA PRESENTED BY ANIMALS
SUBJECTED TO PRESSURES LESS THAN
THAT OF THE ATMOSPHERE
The phenomena presented by animals subjected to a decrease of
pressure are exactly those which were noted in mountain travellers
and aeronauts; however, I have some interesting details to add to
what is already known. But I do not hesitate to confess that since
these phenomena are of a purely descriptive nature, it seems to
me that an exact analysis of them should be made only after a
sufficiently detailed study of their cause; interest in them was
obviously a minor matter.
I think, however, that I should report here the details of some
experiments. It will then be easier to analyze the observations
made and to group them around the principal physiological func-
tions. But the conclusions which we draw from them will be sup-
ported equally by the numerous experiments reported in the first
subchapter of Chapter I, and the second subchapter of Chapter II,
experiments which I thought it unnecessary to describe again here.
After detailing these symptoms, I shall compare them with those
presented by animals asphyxiated in closed vessels at normal
pressure; I shall then deduce from all these facts the method which
must be used in warding off the dangers of decompression, and I
shall report the experiments carried out according to this method
upon animals and even upon man.
660
Symptoms of Decompression 661
Subchapter I
SYMPTOMS OF DECOMPRESSION
Experiment CCXV. March 2. Little dog, put into the big cylinder.
2:05; Normal pressure; respiratory rate 16.
2: 15; Pressure 40 cm. respiratory rate 16.
2:20; Pressure 26 cm. respiratory rate 24.
2:26; pressure 22 cm. respiratory rate 40. Lies down; respiration
dicrotic; it breathes first by the thorax, and then the abdomen rises.
2:36; Pressure 20 cm.; respiratory rate 44.
2:42; Pressure 19 cm.; respiratory rate 36.
2:47; Pressure 18 cm.; respiratory rate 40.
2:55; Inlet cock opened a little; pressure rises to 21 cm. Respira-
tory rate falls to 30. Cock closed. At 3:00, the pressure is only 19 cm.;
respiratory rate remains 30.
3:05; Pressure 18 cm.; Respiratory rate 28.
3:10; Pressure 22 cm.; Respiratory rate 18.
3:14; Pressure 23 cm.; Respiratory rate 16.
3:16; Pressure 25 cm.; Respiratory rate 14.
3:18; Return to normal pressure.
3:24; Respiratory rate 14.
The animal is in good condition.
Experiment CCXVI. March 21. Large spaniel at 3 o'clock in the
large decompression cylinder. Its rectal temperature is 38.5°. At
4:58, pressure is only 25 cm. Normal pressure rapidly restored; tem-
perature of the animal dropped to 36.5°.
Experiment CCXVII. April 2. Female bulldog, having already had
some operations; fastened in the same apparatus.
4:40 at normal pressure respiratory rate 24, pulse 125, rectal
temperature 39°.
4:45; pressure 46 cm.; respiratory rate 24, pulse 110.
4:55; pressure 36 cm., respiratory rate 22, pulse 100.
5:05; the pump is stopped and the air returns to normal pressure;
respiratory rate 20, pulse 120.
The femoral artery has been bared and around it has been placed
a copper wire which records its movements and allows the pulse to
be counted.
5:35; the pump is set in operation and has brought the pressure to
46 cm.; respiratory rate 18, pulse 104.
5:45; pressure 36 cm., respiratory rate 24, pulse 100.
6:15; pressure 41 cm., respiratory rate 18, pulse 100.
6:20; normal pressure; rectal temperature 38.8°.
Experiment CCXV HI. April 23. Dog, which has been given a hypo-
dermic injection of 5 centigrams of morphine hydrochloride.
At 4:30, put into the large cylinder with a manometer in the left
femoral artery. Respiratory rate 20, pulse 126.
At 4:32, pressure is 60 cm., respiratory rate 24 and pulse 120.
At 4:35, pressure is 45 cm., respiratory rate 33 and pulse 184.
662 Experiments
At 4:40, pressure normal; respiratory rate has fallen to 24 and
pulse to 160. The arterial pressure cannot be ascertained exactly
because of clots.
Experiment CCXIX. May 27. Dog, fastened in the big apparatus,
femoral artery exposed and cardiometer inserted.
5:40. Normal pressure; respiratory rate 30; pulse 134; arterial
pressure 16 to 18 cm.
5:55. Pressure 36 cm.; respiratory rate 60; the animal has been
struggling occasionally.
6:05. Pressure 26 cm.; respiratory rate 70, uneven. Connection
made between artery and manometer; mercury rises and oscillates
between 16 and 18 cm. Pulse rate 160 to 180 per minute.
Return to normal pressure in five minutes; respiratory rate 20.
The animal returns to normal state rapidly.
Experiment CCXX. April 22. Cat brought rapidly to 26 cm. of
pressure under a current of air at 2:30. Cannot stand up, lies down
mewing.
3:20. Respiratory rate 33.
3:30. Brought back to 36 cm. because it seemed too sick.
5:30. Still lying curled up.
Taken out at 6 o'clock; did not urinate.
Kept under bell, but at normal pressure, under continued current
of air.
April 23. 10 o'clock in the morning, taken out. Has urinated; its
urine contains no sugar.
Recovers entirely.
Experiment CCXXI. May 14. Cat weighing 3.500 k. Hypodermic
of 10 centigrams of morphine hydrochloride. It is placed under a large
glass bell with a volume of 31 liters; its femoral artery is exposed, and
a copper wire passed around it records the pulse. The animal remains
quiet all through the experiment.
At 4:30, at normal pressure, respiratory rate 25; pulse 105.
Lowering of the pressure is then begun, leaving a current of air,
weak but sufficient to maintain the chemical purity of the air of the
bell.
At 4:50, pressure 56 cm.; respiratory rate 40, pulse 120.
At 5:10, pressure 46 cm.; respiratory rate 40, pulse 120.
At 5:20, pressure 36 cm.; respiratory rate 48, pulse 132.
At 5:30, pressure 26 cm.; the animal is much affected, weak, with
frequent convulsive starts; drools; respiratory rate 56, pulse 140.
Pressure is lowered slowly to 20 cm.; the animal pants, shows
general convulsive movements, and dies at 5:45.
The lungs are collapsed, without crepitation; superficial emphy-
sema; no pulmonary apoplexy.
Dark blood in the left heart.
Experiment CCXXII. February 28. Temperature 13°.
Three rabbits of the same litter are placed at 2 o'clock under large
bells, on the apparatus in Figure 1. A current of air is maintained
under different pressures.
Symptoms of Decompression 663
A: the rabbit weighs 770 gm.; pressure is maintained between 70
and 76 cm.
B weighs 770 gm.; pressure oscillates between 45 and 50 cm.
C weighs 840 gm.; pressure oscillates between 38 and 40 cm.
At 2:30: for rabbit A, respiratory rate 70; for B, 80; for C, 120.
They are removed at 6 o'clock without having shown any remark-
able phenomena.
Temperature of A, 39.5°; of B and C, only 38°.
March 3, experiment repeated with the same results. Rabbit B,
which was brought to 36 cm., then shows convulsive movements, which
do not last. It urinates under the bell; this urine contains no sugar.
Experiment CCXXIII. March 18. Rabbit under a large bell of 31
liters.
3: 15, for a quarter of an hour has been under a current of air at
diminished pressure; it has remained perfectly quiet, with a respira-
tory rate of 94, the pressure being 56 cm.
3:20, pressure 46 cm., respiratory rate 86.
3:25, pressure 42 cm., respiratory rate 66.
3:30, pressure 42 cm., respiratory rate 64.
3:38, pressure 35 cm., respiratory rate 70.
3:50, pressure 15 cm., respiratory rate 90.
3:53, pressure 16 cm., respiratory rate 45, shallow.
Dies at 4 o'clock. Air admitted; the animal, which was swollen,
collapses. Dark blood in the left heart; a few pulmonary ecchymoses.
Experiment CCXXIV. March 20. Rabbit of 2.7 kilos under the large
bell; temperature 20°.
Placed at 2:26 under a current of air with diminishing pressure.
2:30, pressure 56 cm., respiratory rate 105.
2:36, pressure 41 cm., respiratory rate 99.
There is a leak, air enters, and the pressure falls to O; respiratory
rate 81.
2:46, pressure back at 50 cm., respiratory rate 138.
2:50, pressure 44 cm., respiratory rate 105.
2:54, pressure 36 cm., respiratory rate 120.
3:10, pressure 27 cm., respiratory rate 102.
Remains between 27 and 24 cm. until 4: 18; respiratory rate 84.
The animal kept at the same pressure struggles violently at 6:20,
falls on its back, makes 3 or 4 deep respiratory movements, then
remains motionless, dies.
Interior temperature of the bell is 20°; that of the rabbit 32°.
Experiment CCXXV. May 22. Free rabbit in the large bell of 31
liters. At the beginning, respiratory rate 56.
Pressure is rapidly lowered to 56 cm., and the animal is kept there
20 minutes; its respiratory rate increases to 60.
Pressure lowered to 36 cm.; respiratory rate rises to 100. But the
animal remains quiet, without apparent inconvenience.
Pressure lowered to 26 cm., to 22 cm., without the rabbit seeming
much affected. At 16 cm., symptoms appear. At 12 cm., it struggles
violently, is seized with general convulsions, and dies in a minute.
664 Experiments
The lungs are the seat of great congestion, with hemorrhagic
spots and scattered emphysema. Their density is greatly increased,
but they still float.
Experiment CCXXVI. May 23. Rabbit. Same bell, same decom-
pressions, same general results.
Experiment CCXXVII. March 10. Temperature 15°. Guinea pig
weighing 320 gm. placed in the bell of 27 liters. At 2:50, I open the
communicating cock between this bell and a large cylinder in which
the pressure has been greatly lowered; the pressure in the bell in-
stantly falls to 16 cm. The animal does not appear to suffer. Respira-
tory rate 129.
Since the bell is not entirely air-tight, the pressure rises slowly.
At 3:13, it is 21 cm.; respiratory rate 104. I then open the cock";
the pressure drops to 17 cm.; the animal falls on its side, and rises
almost instantly; respiratory rate 112.
At 3:32, pressure 19 cm., respiratory rate 120; animal quiet.
At 3:35, third opening of the cock; pressure drops to 16.5 cm.;
staggers slightly.
At 3:42, the pressure has risen to 18 cm. Fourth opening of the
cock; pressure falls to 13.5 cm.; the guinea pig falls on its side; respir-
atory rate 108.
At 3:45, pressure 14 cm.; respiratory rate 78; on its side.
At 3:51, pressure risen to 17 cm. Fifth opening of the cock; pres-
sure falls to 11.5 cm.; the animal, which had risen slightly, lies down
slowly; respiratory rate 36.
At 3:55, pressure 13 cm.; respiratory rate 69; on its side.
4:01, pressure 14.5 cm.; respiratory rate 92; recovered considerably.
4:08, pressure 14.7 cm., respiratory rate 90. Violent jerking of the
feet, the subcutaneous muscles, and the head; from this point to the
end, the jerking keeps increasing.
4:13, 16 cm.; respiratory rate 93.
4:15, sixth opening of the cock; pressure falls to 13.5 cm.; a little
more jerking, but the animal remains on its feet; respiratory rate
rises to 108.
4:21, pressure 15 cm.; respiratory rate 85.
4:30, pressure 16 cm., respiratory rate 90; seventh opening of the
cock; pressure 11.5 cm.; the animal, which has been crouching, raises
its head twice, then lies down slowly. The violent jerking stops for a
few minutes.
4:33, pressure 13 cm.; respiratory rate 52.
4:39, pressure 15 cm.; the animal has remained lying down. Pres-
sure lowered to 12 cm.; does not seem to notice it.
4:46, pressure 14.5 cm.; respiratory rate 66.
4:53, ninth opening of the cock; pressure falls to 11.5 cm.; the
animal raises its head, but remains lying down.
4:55, pressure 12 cm.; respiratory rate 84.
4:58, pressure 13 cm., respiratory rate 60.
4:59, tenth opening, which lowers the pressure to 10.7 cm.; the
animal struggles considerably, and gets on its side.
5:00, pressure 11 cm.; respiratory rate 55.
Symptoms of Decompression 665
5:03, pressure 12 cm.; respiratory rate 60.
5:12, pressure 13 cm.; I lower it to 11.7 cm.; no apparent effect.
5:20, pressure 14 cm.; respiratory rate 65.
5:22, twelfth opening; pressure falls to 10.8 cm.
The animal twists and rolls on its side, with tonic and clonic
convulsions.
5:24, pressure 11.7. The convulsions have ceased; only slight quiv-
ering of the feet; it remains lying down, and never gets up again.
5:37, pressure 14.7 cm.; respiratory rate 80.
5:40, pressure 15 cm.; lowered to 11.7 cm.; the animal does not
move but is evidently swelling.
5:53, pressure 15.5 cm.; same state. Fourteenth opening of the
cock; lowered to 12.5 cm.
6:45, pressure 19 cm.; animal in same condition. Communication
with outside air opened wide. Swelling diminishes, but the animal
breathes no better; it is almost insensible; its rectal temperature has
fallen to 20°.
It remains lying on its side and dies in the night.
No ecchymoses in the lungs.
Experiment CCXXVIII. June 11; temperature 21°. Guinea pig,
weighing 485 grams; put under a bell of 13.5 liters.
From 3:24 to 3:30, the pressure is lowered to 26 cm.; the animal
has not been struggling; but then he staggers, then recovers fairly
well, scratches his nose, etc.
At 3:32, same state; respiratory rate 100; walks a little.
At 3:34, lowered to 20 cm.; respiratory rate rises to 135; the
animal remains motionless.
At 3:35, pressure 17.5 cm.; lies down on its belly.
At 3:40, pressure 13.7 cm.; respiratory rate 80, deep, painful;
pupils soon dilate; slight convulsive jerking comes on.
At 3:45, same pressure maintained; the animal falls on its side;
convulsive movements, with rigidity. Belly enormously swollen.
Dies at 3:49.
At 4:02, rectal temperature is 34.6°.
Experiment CCXXIX. June 17; temperature 22°. Guinea pig in
the large bell; current of air.
From 2:50 to 3:45, pressure is lowered to 36 cm.
Then, progressively, from 3:45 to 4:20, to 13 cm.; respiratory rate
is then 20, and the animal remains lying on its side.
At 4:25, pressure lowered for an instant to 10 cm.
The animal makes convulsive movements of the feet and head; the
breathing is difficult and jerky.
Pressure maintained at 12 cm. until 4:40, then returned to normal.
Its rectal temperature is then 25°. Very soon it rises on its feet;
regains strength, gets warm; at 4:50, its rectal temperature has risen
to 31°.
It dies.
Let us now examine the results of these experiments successively
from the point of view of the different physiological functions.
666 Experiments
1. Respiration.
In general, the respiration quickens when the pressure is
lowered. But nothing is more irregular than these modifications in
the respiratory rate. Here the effect of the suddenness of the
phenomena is of greatest importance. The animal is startled, stirs
about, struggles; it is irritated by the expansion of gases of which
I shall speak under the heading of digestion, and all these effects
accelerate its breathing. But it often happens that the respiration
grows slower and becomes deeper; that is almost the rule at very
low pressures. This is noticed particularly when the animal re-
mains quiet; agitation has always seemed to me to speed up the
breathing.
In a word, here as in all the other circumstances, lessening of
pressure acts the same as asphyxia. We know that in asphyxia in
a closed vessel there is also a phase of respiratory acceleration,
followed by a phase of retardation in which the thoracic move-
ments are made slowly and painfully. The experiments reported
in Chapter I also show frequent examples of this respiratory
acceleration in animals kept at various low pressures.
But to show how difficult it would be to include all these facts
in a general formula, it is sufficient to study the experiments closely,
being careful especially to show by graphs the results in which
comparison is difficult.
In Figures 47 and 48, in which the graphs show only respira-
tory movements, and in Figures 49, 50, and 51, in which the pulse
rate is also plotted, the direction of the arrows indicates the series
of successive alterations in pressure to which the animals were
subjected. When the arrow points to the right, the pressure de-
creases; towards the left, it increases. Pressures are reckoned on
the axis of the abscissae; on the vertical axis are written the num-
bers corresponding to the respiratory movements R and to the
pulse P.
Line B (Fig. 47) gives the details of Experiment CCXV, made
on a dog. We see that here effects were produced in a simple and
regular manner, the number of respirations increasing or decreas-
ing inversely as the pressure.
Line A, on the contrary (Exp. CCXVII, another dog), shows
a singular complication; in a general way, the number of respira-
tory movements decreases as the pressure decreases.
We note similar differences with rabbits. While Experiment
CCXXV shows a simple relation between the pressure and the
number of respiratory movements, Experiment CCXXIV, repre-
Symptoms of Decompression 667
sented by line C, and Experiment CCXXIII, represented in D, seem
to defy any generalization.
But the maximum of complication imaginable is furnished by
Fig. 47 — Modification of the number of respiratory movements under the
influence of decompression: A, B, dogs; C, D, rabbits,
668 Experiments
the graph of Figure 48, representing Experiment CCXXVII, made
on a guinea pig.
Indeed, we find all possible combinations and the most astonish-
ing differences in both the direction and the amount of the modi-
fications in respiratory rate. Let us remember that this experi-
ment had an exceptional duration, and that the animal had been
m
■
i
m
m
I
Fig. 48 — Modification of the number of respiratory movements under the
influence of decompression: Guinea pig, Experiment CCXXVII.
Symptoms of Decompression 669
chilled to the point of death before being returned to normal
pressure.
These facts, which I might have multiplied, serve to show that
outside the general rule are found numerous exceptions, which
explain the lack of agreement on this subject among observers on
mountains and aeronauts. We shall return to this point later.
Finally, let us note that besides the rate, respiration is affected
in its rhythm; it becomes irregular, often dicrotic, sometimes
deeper, and I have seen it in dogs at very low pressures separated
into two parts: thoracic inspiration and then diaphragmatic in-
spiration. Moreover, every general movement is accompanied by
a sort of anhelation. All that agrees with what has been observed
in man.
The lessening of the maximum of respiratory capacity was
shown by an experiment made upon myself, the details of which
will be given in Subchapter III. At normal pressure it was repre-
sented by the number 17.3, arbitrary value; at 430 mm. of pressure,
it had fallen to 11.8, and after a half-hour stay under pressures of
about 420 mm., it was only 9.9.
2. Circulation.
Besides the experiments reported above, I think I should give
the details of one which I made upon myself.
Experiment CCXXX. July 29, the temperature being 23.5°, the
pressure 75.5 cm., I enter the large cylinder, and sit down there,
remaining very quiet.
At 2:35, my pulse rate was 64, at normal pressure.
At 2:45, pressure 72 cm.; pulse rate only 60; perhaps resting
alone was enough to cause this drop.
At 2:55, pressure 63 cm.; pulse 63.
At 3 o'clock, pressure 60 cm.; pulse 67. I am now forced, by the
expansion of the intestinal gases, to open my garments wide.
At 3:08, pressure 55 cm.; pulse 67. I now rise and take two or
three steps in the cylinder; my pulse immediately rises to 80.
I let the pressure slowly rise.
At 3:15, pressure 62 cm.; pulse 63.
At 3:24, pressure 72 cm.; pulse 60.
At 3:28, return to normal pressure; pulse only 59.
I leave the cylinder and walk rather rapidly in the laboratory;
my pulse rises only to 67.
I have experienced no disagreeable sensations, except the tension
of intestinal gases, and a need of swallowing my saliva frequently to
clear the Eustachian tube.
The experiments upon myself, whose details Subchapter III of
the present chapter will recount, give the same results.
670 Experiments
We see that in the decompression chamber the circulatory ac-
celeration appears quickly, as aeronauts had already observed. It
increases considerably at the slightest movements.
Experiments on animals give evidence of the same sort. They
usually show remarkable agreement between the variation of the
number of respiratory movements and that of the cardiac beats.
Fig. 49 — Simultaneous modifications of the number of respiratory move-
ments R and the pulse P under the influence of decompression.
Cat, Experiment CCXXI.
Figure 49 gives a remarkable example of this, taken from Ex-
periment CCXXI, made on a cat. The line of the pulse is marked
P; it corresponds to Column P of the ordinates. The line of the
respiration is indicated by the letter R, as is the value of its ordi-
nates. The pressures are reckoned on the axis of the abscissae.
The same agreement, though less constant, is observed in Figure
50, which shows the observations made during Experiment CCXVIII.
Finally, in Figure 51, which gives the strange results of Experi-
ment CCXVII, we see that if the number of respiratory movements
diminishes with the pressure, the same is approximately true of
Symptoms of Decompression
671
the heart beats. The latter even follow this general rule much
more exactly than the former.
Because of the clots which formed in the arteries and the ap-
paratuses, it has been almost impossible for me to measure in a
consistent manner the modifications of the cardiac pressure. The
Fig. 50— Dog, Experiment CCXVIII. Fig. 51— Dog, Experiment CCXVII.
Simultaneous modifications of the number of respiratory move-
ments R and the pulse P under the influence of decompression.
rare observations which I could make showed only slight diminu-
tions; it seemed to me that it would be necessary to go very far to
obtain noteworthy differences in animals which must be kept
motionless. At a pressure of 26 cm., the heart had retained the
same strength as at normal pressure (Exp. CCXIX). The results
would no doubt be different, if the animals were performing labor
comparable to that of travellers climbing a mountain.
672 Experiments
I add that under the influence of pressures which are very weak
and very quickly reached, I have sometimes seen nasal and pul-
monary hemorrhages. But this is a very rare symptom in animals;
in fact, it is not as common in man as is ordinarily stated.
3. Digestion.
As a certain degree of decompression is approached, travellers
have experienced nausea; I have likewise seen my animals stagger,
wag their heads with evident distress, and vomit. Almost all birds
showed this symptom.
Animals subjected to extreme decompressions, and especially
herbivores, were swollen in a very remarkable way by the expan-
sion of their intestinal gases. It seemed to me, in some cases, that
this swelling was great enough to act even on the respiration and
hamper its movements.
I have verified upon myself this disagreeable swelling, in Ex-
periment CCXXX and in several others of the same sort reported
in Subchapter III; but it never brought serious inconvenience,
when the garments which confined the waist were unfastened and
opened; besides, the gases easily found vent through the two in-
testinal orifices.
I even tried direct experiments, to obtain ocular evidence of
this evacuation of gas.
Experiment CCXXXI. December 10. A dog, which had just been
killed by direct application of electrical stimulation to the heart, was
fastened on a trough and placed in the decompression cylinders. Into
its rectum was inserted a glass elbow tube, which by means of rubber
packing completely closed the anus. The other end of the tube was
immersed several centimeters deep in a glass full of water.
The decompression was then begun, and as fast as the barometer
fell, bubbles of gas burst on the surface of the water, and the greater
the speed of the decompression pump, the more rapidly the bubbles
followed each other.
However, the belly was visibly swelling.
On return to normal pressure it suddenly collapsed, and water
entered the rectum.
Experiment CCXXXII. February 27. Dog killed by hemorrhage,
and prepared like the dog in the preceding experiment. It had also
in its esophagus a tube immersed a little way in the water.
At the very first strokes of the pump, the air left the anus con-
stantly; several times the machine was stopped, and the gaseous evac-
uation ceased immediately. But no gas left by the esophagus.
The pressure was lowered to 30 cm. in 2 hours and 20 minutes.
On return to normal pressure, the belly collapsed.
Symptoms of Decompression 673
So the expanded gases leave very easily by the anus; but the
last experiment shows, strangely enough, that they cannot, in a
cadaver, escape by the cardia, nor probably by the pylorus, so that
the stomach is distended. But in the living being this is not the
case, and eructation is produced, thanks to muscular action.
This influence of decompression upon the intestinal gases is not
very important, but is interesting as being the only effect (or
nearly so) that it causes as a purely physical agent.
On several occasions in my cylinders I have also felt nausea
and sickness caused by decompression.
4. Nervous and Muscular Effects.
When the pressure is lowered considerably, we have seen the
muscular strength of animals diminish rapidly. Birds refuse to
attempt to fly. They all quickly become and remain motionless,
no matter how much one excites and threatens them, or how fierce
or frightened they seemed at first; at lower pressures, they are
no longer able to remain upright but crouch; at still lower pres-
sures, they fall on their sides.
In Subchapter III, I shall give the details of experiments in
which I underwent quite low pressures. I mention here this inter-
esting note that, when I wanted to raise my leg which had been
bent for some time, it was seized by convulsive jerks which I
could not control, but which ceased as soon as I rested it once more
on the floor. Similar quiverings have been reported by aeronauts,
who generally attributed them to the cold. M. Sivel, who has
experienced them, compares them to the period of chill in attacks
of intermittent fever.
Animals subjected to rather low pressures become, as it were,
insensible and indifferent to everything; it seems evident to me
that sensibility as well as strength of reaction fail them at the same
time. Furthermore, in man, sensorial impressions are strangely
lessened in keenness; we shall see the proof of that in the story of
the ascent of Croce-Spinelli and Sivel. The same thing is true of
moral energy, of intellectual activity; in one of my experiments,
I was surprised at not being able to multiply 28, the number of my
heart-beats in a third of a minute, by 3. I had to be satisfied with
writing down these numbers in my notebook; this weakness, more-
over, left me quite indifferent.
When decompression approaches the fatal limit, when it has
lasted a long time, or when it has been brought on very suddenly,
we often see occurring in the animals convulsive jerkings which
674 Experiments
recall, in an exaggerated way, the trembling I myself felt. At the
extreme limits, when death comes, real convulsions appear, whose
violence is in proportion to the strength which the animal then
retains.
When the decompression has been brought on slowly, when it
has lasted a long time, when the animal is much weakened and
chilled, no convulsions are observed, or they are very slight. I
have shown elsewhere that the same thing is true in ordinary
asphyxia, in closed vessels. For example, here is an experiment.
Experiment CCXXXIII. September 17. Two starlings.
A. One is placed under a bell of 900 cc, inverted over a basin of
water. At the end of three quarters of an hour violent convulsions
occur, and the bird dies.
B. The second is put under a bell of 14 liters, also inverted over
water. At the end of about 6 hours, respiration seems much affected.
Death occurs after 9 hours and 25 minutes, with gradual phenomena,
without convulsions.
The convulsions produced by decompression, by asphyxia, and,
I add, by hemorrhage, are merely a violent response of the spinal
cord, over-stimulated by a sudden change in the conditions of its
nutrition. If the transitions are carefully managed, if there are
only slow and progressive changes, we see no more violent symp-
toms, no more convulsions.
The experiments reported in Chapter II, Subchapters I and IV,
show that in decompression carbonic acid diminishes considerably
in the blood. When death is reached, when convulsions occur, the
animal has lost more than two-thirds of it. Very evidently the
convulsive phenomena must not be attributed to this gas, as is
stated in the theory propounded in 1850 by M. Brown-Sequard, and
accepted today by a great number of physiologists.1 We shall see
directly, in another chapter, that carbonic acid is a narcotic of the
nerves and the muscles, far from tending to over-stimulate them.
Here, I simply wish to call attention to the fact that in all the
experiments which this learned physiologist has brought to sup-
port his statement, the oxygen diminished rapidly to the point of
disappearing, while the carbonic acid itself hardly increased in the
blood and the tissues. What we have just said is enough, without
further insistence, to prove that it is to this sudden decrease of
oxygen that we should attribute the medullary excitations and
the muscular contractions.
I think I should add here that in animals killed by decompres-
sion, as in animals rapidly asphyxiated or bled to death, one can
Symptoms of Decompression 675
see, in the moments which precede death, the intestines twisting
in the belly in violent peristaltic movements.
5. Nutrition.
All the phenomena which we have just reviewed are only the
consequences of disturbances of the nutrition of the tissues, dis-
turbances due to the lessened quantity of oxygen in the blood. Our
experiments on superoxygenated atmospheres have shown, in fact,
that decompression as a physical agent plays a role that is almost
negligible, and that the question is exclusively of a chemical
nature.
We ought therefore to study carefully these nutritive dis-
turbances, which manifest themselves so clearly to us by the lower-
ing of temperature. We shall therefore inquire into the modifica-
tions undergone by the chemical phenomena of respiration: 1.)
oxygen absorption, which is the primary factor; 2.) carbon dioxide
excretion, which measures the energy of the intra-organic combus-
tions; and 3.) the renal excretion, which can also serve as a measure
of the chemical activity of the living body.
1. Chemical phenomena of respiration. The numerous experi-
ments reported in Chapter I on the death in closed vessels of ani-
mals subjected to more or less weak pressures make it possible
for us to calculate easily the quantity of oxygen consumed and the
quantity of carbonic acid exhaled, per unit of time, for each animal
species, or for each kilogram of animal. I shall do so in a moment,
taking into account only the experiments in which the behavior
of the animal has been noted, for it is quite evident that results can
be modified, even reversed in their general direction, by the
single fact of a considerable uneasiness compared to an absolute
repose.
But it seemed to me desirable, for this delicate verification, to
carry out special experiments, in which special precautions should
be taken. Besides, the experiments of Chapter I end in death, and
although comparable in this respect, they cannot be as convinc-
ing as those in which the animals survive.
Here are some of these new data.
Experiment CCXXXIV. June 30. Rats of the same litter, each
weighing 50 grams.
A. Confined from 4:16 to 4:58 (42 minutes) under an airtight
bell, containing 3.2 liters; normal pressure.
B. Confined from 4:34 to 5:18 (42 minutes) under a bell of 7.1
liters, in which the pressure is rapidly brought to 34 cm. The volume
of the bell corresponds to 3.17 liters at normal pressure.
676 Experiments
C. Confined from 4:30 to 5:12 (42 minutes) under a bell of 11.5
liters, in which the pressure is rapidly brought to 20 cm. The volume
of the bell corresponds to 3.03 liters at normal pressure.
The three animals remain quiet, except B, which moves a little.
C lies on his belly, but gets up when we excite him a little; he is
better towards the end of the experiment; none of them appears then
to suffer from the confinement.
When the experiment is over, the rectal temperature of A is 38.1°;
of B, 33.1°; of C, 32.0°.
The composition of the air is as follows:
A. O 14.8; CO* 5.2.
B. O 16.0; COa 3.9.
C. O 17.2; CO* 3.2.
So the oxygen consumed, in vessels containing about the same
quantity of air, was for A, 6.1 per cent; for B, 4.9 per cent; for C,
3.7 per cent.
Establishing now the absolute value of oxygen consumption and
carbonic acid production during the 42 minutes of the experiment, we
find that:
Oxygen CO.
A, who had at his disposal 672 cc, has consumed 195 and produced 166 cc.
B, who had at his disposal 666 cc, has consumed 155 and produced 123 cc.
C, who had at his disposal 636 cc, has consumed 112 and produced 97 cc.
Experiment CCXXXV, June 3. Rats of the same litter. Outside
temperature 25°.
a. Placed from 2:20 to 4:50 (2 hours, 30 minutes) at normal pres-
sure, under a bell of 7.6 liters.
b. Placed from 2:40 to 5:15 (2 hours, 35 minutes) at a pressure of
50 cm., under a bell of 11.5 liters, whose capacity at this pressure
corresponds at normal pressure to 7.57 liters.
c Placed from 2:55 to 5:30 (2 hours, 35 minutes) at a pressure of
37 cm., under a bell of 15.5 liters, whose capacity at this pressure
corresponds at normal pressure to 7.53 liters.
The animals remain very calm, and do not seem inconvenienced.
At the end of the experiment, the temperature of a is 35°; that of b,
34°; that of c, 32.5°. (The thermometer was not exact, and these values
should be considered not as absolute, but as comparative.)
Chemical analysis gave:
For a, : O? 11.3; CO* 8.1.
For b, : 0= 12.5; CO* 7.8.
For c, : O? 13.1; CO.- 5.9.
Making the same calculations as for the preceding experiment, we
find that in 2 hours and 35 minutes
Oxygen CO?
a, who had at his disposal 1596 cc, consumed 729 and produced 615 cc.
b, who had at his disposal 1589 cc, consumed 636 and produced 590 cc.
c, who had at his disposal 1581 cc, consumed 587 and produced 452 cc.
Symptoms of Decompression
677
If we calculate the oxygen consumption for one hour, to com-
pare the results of these two experiments more easily, we find that
Oxygen CO
A, at normal pressure, consumed 278 cc, and formed 237
a, at normal pressure, consumed 282 cc, and formed 246
b, at 50 cm. pressure, consumed 246 cc, and formed 237
c, at 37 cm. pressure, consumed 227 cc, and formed 180
B, at 34 cm. pressure, consumed 221 cc, and formed 175
C, at 20 cm. pressure, consumed 160 cc, and 'formed 138
The remarkable agreement between experiments A and a on
the one hand, c and B on the other, shows that, in spite of the
causes of error inherent in our experimental procedure, — causes
of error which compel us to disregard the third figure in the num-
bers reported above, — we can state definitely that the oxygen con-
Fig. 52 — Consumption of oxygen and production of carbonic acid at differ-
ent pressures.
678 Experiments
sumption in a given time diminishes when the pressure itself
diminishes; this fact is shown very clearly in graph A of Figure 52,
which indicates the average of the results of the two preceding
experiments.
The production of carbonic acid gives rise to similar conclu-
sions. Graph A' expresses its different stages.
Let us refer now to the experiments of Chapter I, Subchapter I,
and particularly to Table I, which summarizes them. We find here
all the elements necessary for our calculation. Now if, without
following all the details of the experiments, we take averages at
different decompressions, we see that, in one hour, a sparrow:
Oxygen CO
At normal pressure (Exp. 1, 2, 3, 4) consumed 147 cc. and produced 122 cc.
At about 50 cm. (Exp. 5, 6, 7, 8) consumed 118 cc. and produced 97 cc.
At about 30 cm. (Exp. 13, 14, 17) consumed 80 cc. and produced 65 cc.
At about 24 cm. (Exp. 24,25,26,27) consumed 72 cc. and produced 57 cc.
At about 20 cm. (Exp. 33) consumed 60 cc and produced — —
These results are indicated by Graphs B and B' in Figure 52.
We see that, in spite of the important difference of methods (since
here the sparrows remained until death, and consequently towards
the end of life were all subjected to the same oxygen tension, the
tension which produces death) , the results have remarkable agree-
ment with the preceding ones, not only as to the general direction
of their variation, but even as to the proportion of this variation.
I am therefore quite justified in drawing from this collection
of data the conclusion that, at low barometric pressures, an animal
consumes, in a given time, a considerably smaller quantity of oxy-
gen, and produces a considerably smaller quantity of carbonic acid
than at normal pressure. This diminution, which increases propor-
tionately as the pressure is lowered, is clearly apparent at a diminu-
tion of a third of an atmosphere, which corresponds to a height
of more than 3000 meters above sea level.
We shall refer frequently to the consequences of this important
principle, which is sufficient explanation, evidently, of all the symp-
toms caused by lowered pressure.
2. Urinary excretion. After having ascertained that oxygen
consumption and the intra-organic combustions which result in a
production of carbonic acid are considerably diminished by a stay
in decompressed air, I had to investigate whether these modifica-
tions of nutrition do not also appear in the urinary excretion.
I have given particular attention to urea. The analyses were
made sometimes by the method of M. Grehant (use of the Milon
Symptoms of Decompression 679
reagent and a vacuum), sometimes by that of M. Yvon (by hypo-
bromide of soda) .
Dogs were used as subjects of my experiments. The animal,
enclosed in advance in the cylinders in which the decompression
was to be carried on, was fed on a definite diet for two or three
days; then we calculated the quantity of urea excreted in 24 hours,
drawing the urine two mornings in succession, because dogs which
are confined urinate at very irregular intervals. Of course, the
urine voided spontaneously by the animal was carefully collected.
The decompression having been maintained for several hours, we
made a new analysis including the urine of the day from the
morning of the experiment to the next morning. Sometimes, we
also collected in the same way the urine of the 24 hours following.
Here are some of the results obtained.
Experiment CCXXXVI. July 3. Dog weighing 12 kilos; eats every
day, between 7 and 8 in the morning, 250 gm. of bread and 250 gm.
of meat boiled together with 500 gm. of water.
July 4, at 10 in the morning, dog's bladder emptied.
July 5, bladder emptied again at the same hour; he has not uri-
nated spontaneously; we obtain thus 260 cc. of urine, which treated
by the Yvon method give 7248 cc. of nitrogen.
We conclude then that he voided 19.4 gm. of urea.
On that day, from 11 to 6, the animal was subjected to a pressure
of 38 cm.
After he had left the apparatus, catheterization brought 100 cc. of
urine, containing 7.4 gm. of urea. The next day at 11 in the morning,
another catheterization, giving 80 cc. of urine, with 4.4 gm. of urea.
Produced then in these 24 hours only 11.8 gm. of urea.
The next day (July 7), catheterized at 1:15; the urine, added to
what he voided during the night, amounts to 240 cc, containing 15.4
gm. of urea.
Experiment CCXXXVII. Same dog, kept on the same diet.
Catheterized July 7 at 1:15, as has just been said, then July 8 at
10:30 (21 hours), gives 246 cc. of urine containing 19.6 gm. of urea.
July 8, from 10:55 to 4:45, is kept at 38 cm. pressure.
July 9, at 1:15, has given (in 27 hours) 385 cc. of urine containing
24.7 gm. of urea.
If we reduce these secretions to their proportionate value for 24
hours, we find:
At normal pressure: 22.4 gm.
At a half-atmosphere, 21.9 gm.
Experiment CCXXXVIII. July 13. Same dog, subjected to same
procedure. But he is tired of being confined.
From July 13, at 7:45 in the morning (fasting) to July 14 at 8 in
the morning (fasting) voided 200 cc. of urine, giving 13 gm. of urea.
July 14, from 8:30 in the morning to 5:45 in the evening, kept
at a pressure varying from 30 cm. to 35 cm. Does not seem weakened.
680 Experiments
July 15, at 8 in the morning (fasting), all the urine collected,
amounting to 211 cc. with only 7 gm. of urea.
In the following 24 hours, he voids 130 cc, with 8.2 gm. of urea.
Experiment CCXXXIX. June 9. Dog weighing 19.3 kilos. Kept for
4 days on a ration of 375 gm. of bread, 375 gm. of meat, and 500 gm.
of water.
From June 9, at 10 o'clock in the morning to June 10, at 10:45,
voided 276 cc. of urine, which analyzed by the Grehant method con-
tains 27.9 gm. of urea.
June 10, from 11:30 in the morning to 6:30 in the evening, kept
between 25 and 30 cm. of pressure. On leaving the apparatus, he is
very much weakened, almost refusing to stand up. Catheterization
extracts only a few drops of urine.
June 11, at 10:30 in the morning, the catheter brings 390 cc. of
clear urine, containing neither sugar nor albumen. It gives 20.7 gm.
of urea.
Experiment CCXL. June 17. Same dog, kept on the same diet, but
not confined. June 17, at 10 in the morning, placed in the apparatus;
June 18, at the same hour, gave 370 cc. of urine, containing 27.5 gm.
of urea (Yvon method).
June 18, from 11 to 5:30 kept between 36 and 38 cm. pressure.
Respiratory rate rises from 16 to 24 and even 30. Leaves the appara-
tus a little weakened; rectal temperature has fallen from 39.2° to 39.0°.
Catheterization yields 100 cc. of urine, without sugar, containing
7.5 gm. of urea; the next day at noon produces 130 cc. of urine con-
taining 6 gm. of urea; about 13.5 gm. in the 24 hours.
Experiment CCXLI. June 23. Same dog; regular diet, but a some-
what smaller quantity.
At normal pressure, in 24 hours, yields 250 cc. of urine contain-
ing 20 gm. of urea (Yvon method).
From 1 o'clock to 6:30 subjected to a pressure of 38 cm. Voids
in the 24 hours 220 cc. of urine containing 14.4 gm. of urea.
The next day, at normal pressure, yields in 24 hours 36.8 gm. of
urea in 600 cc. of urine.
Experiment CCXLII. October 26. Dog weighing 20.5 kilos; kept for
preceding 10 days on the following daily ration: 250 gm. meat, 250
gm. bread, 500 gm. water.
From October 26, at 9 in the morning, to October 27, at 9:30,
voids 336 cc. of urine containing 23.4 gm. of urea (Yvon method).
October 27, from 9:45 to 5, subjected to a pressure varying from
30 to 40 cm. The next day, at 9:45, yields 570 cc. of urine, with 23.5
gm. of urea.
In the following 24 hours, yields 330 cc. of urine with 17.3 gm. of
urea.
The day after, 390 cc. of urine, with 21.8 gm. of urea.
These experiments show conclusively that a stay of several
hours in an atmosphere whose pressure has been lowered by more
Symptoms of Decompression 681
than half diminishes considerably the quantity of urea excreted
in 24 hours. Whatever may be the various causes of error inherent
in the experimental procedures, the exact agreement in direction,
if not in absolute value, of the variations in all the experiments
established satisfactorily a degree of certainty.
This decrease has not been proportional to the decrease in pres-
sure; it has varied with circumstances generally unknown; its
maximum was 50.8 per cent in Experiment CCXL.
In examining the record of these experiments, we notice that in
number CCXLII, the decrease in urea was not seen on the day of
the decompression, (23.4 gm. to 23.5 gm.) but the next day (17.3
gm.) ; the day after, normalcy was almost established (21.8 gm.) .
In another case, Exp. CCXLI, on the day after the stay in decom-
pressed air, the quantity of urea yielded was much increased, and
rose considerably above the original figure, under normal pressure.
These are questions of detail for the study of which we should be
forced to increase the number of experiments, taking as subject
man, in whom uniformity of diet, uniformity of movement, etc., can
be more exactly obtained.
Disregarding these secondary points, it is established that at
low pressures the decrease in activity of chemical phenomena af-
fects not only those which produce carbonic acid, but also those
which cause the excretion of urea. The whole combination of
intra-organic acts of oxidation is therefore considerably decreased
when the air is sufficiently expanded.
We must note that uric acid did not seem to be increased in the
urine of the dogs, when the urea diminished; at least we did not
note any precipitate, either spontaneous or following the acidifica-
tion of the urine. This fact supports many others in showing that
urea is not a product of the oxidation of uric acid, but that these
two substances proceed from different chemical transformations.
3. Sugar of the liver and of the blood, glycosuria. I have re-
peatedly established the presence of sugar in the urine of animals
kept for several hours at low pressures. But the phenomenon
always appeared in an irregular manner, so that I have not been
able to reproduce it at will in comparable experiments.
On the other hand, when the decompression is great and acts
for a long time, sugar is more or less decreased in the liver; it may
even wholly disappear. Example:
Experiment CCXLIII. August 1. Rat, kept in a large bell, with air
renewed from time to time, at a pressure oscillating between 30 and
40 cm., from 1:10 to 6:45.
682 Experiments
Pressure is then lowered to 8 cm.; the animal dies at the end of 5
minutes.
The liver is removed immediately, thrown into boiling water, then
crushed with charcoal; no trace of sugar.
Here then the chemical process which transforms the glycogen
of the liver into sugar is also hampered by the decreased pressure.
Here again, we find the absolute similarity between death by de-
compression and slow asphyxia in closed vessels. We knew that
in asphyxia also glycosuria is a phenomenon which is sometimes
but not always observed. We understand that multiple conditions
control its appearance. In fact, it is necessary that at a certain
moment the liver should still be furnishing a great quantity of
sugar to the blood, and that oxidation within the blood should at
the same time be greatly hindered. These are conditions which
are very complex and hard to produce at will.
The amount of sugar in the arterial blood should also be care-
fully ascertained. Here are some experiments performed for this
purpose; the analyses were made by M. Dastre, who has had great
experience in this kind of research.
Experiment CCXLIV. February 26. Small Havanese dog.
Its arterial blood contains per kilogram 0.95 gm. of glucose.
It is placed under a large bell, at a pressure of about 20 or 25 cm.;
at the end of a quarter of an hour it dies, the pressure having perhaps
gone too low through carelessness.
The blood of the right heart contains 3.48 gm. of glucose per
kilogram.
Much glycogenic material in the liver.
Experiment CCXLV. February 27. Small dog, puny, sickly.
Its arterial blood contains 1.80 gm. of glucose.
Placed for three hours, under a current of air, at a pressure vary-
ing between 15 and 25 cm. Then killed by sudden decompression
falling to 5 cm.
Blood of the right heart contains 1.84 gm.
Much sugar and glycogenic material in the liver.
No urine in the bladder; the kidneys and bladder, crushed in
water, do not reduce to copper reagent.
The temperature was not measured; but the animal did not seem
to have grown perceptibly colder.
Experiment CCXLVI. March 3. Small dog.
Arterial blood contains 1.5 gm. of glucose.
Brought in 20 minutes to a pressure of 17 cm., where it remained
for 10 minutes. Then killed quickly by decompression (9 cm.).
Arterial blood, taken from the heart during the last beats, con-
tains 3.3 gm. of glucose.
Rectal temperature 38°.
Symptoms of Decompression 683
Much sugar and glycogenic material in the liver .
No urine; the bladder and kidneys, crushed with water, give no
sugar.
And so, when the decompression has not lasted long but has
been great, sugar increases in the blood; it returns to its normal
value when the decompression has been sufficiently prolonged. This
difference I think can be explained in the following manner: the
liver, irritated by the action of blood that has suddenly lost its
oxygen, pours into the circulation a large quantity of sugar which
is shown by analysis, if the animal is killed in a short time; if, on
the contrary, there is some delay, this sugar disappears, and since
the liver is producing less and less of it, it returns to its usual value,
then lessens and finally disappears, even from the liver, as is shown
by Experiment CCXLIII on the rat.
4. Temperature. It is not surprising to see the temperature of
the body fall, in consequence of this lessening of the chemical
phenomena of the organism.
This phenomenon had already been observed in mountain as-
cents. Some attributed it to the surrounding cold, others to the
labor performed, and in this connection I spoke, in the historical
part, of the theory of M. Lortet.
But the experiments reported above, show, by many examples,
that the temperature of animals subjected to decompression falls
without their doing the least work, without the air being chilled,
and without the possibility of attributing the phenomenon to the
current of air which must be kept around them to avoid the ac-
cumulation of carbonic acid. The loss is generally 2 or 3 degrees
for a drop of a half or two-thirds of an atmosphere in a half-hour,
for example. But that depends on the degree of the decompres-
sion, its duration, and the animal species.
Thus, in a large dog (Exp. CCXVI), brought in two hours to
25 cm. pressure, the temperature had dropped 2 degrees.
All the experiments give similar results. I shall mention par-
ticularly, because it eliminates the effect of the current of air (Exp.
CCXXII), that in which three rabbits were subjected, one to a
current of air at normal pressure, the second to a current under a
pressure of 50 to 55 cm., the third to a current under a pressure of
40 cm., all of them for four hours. At the end of this time, the
temperature was, for the first, 39.5°; for the other two, 38°. The
birds mentioned in Chapter I, Subchapter I, present phenomena of
the same sort, whose details it would be useless to stress.
But it is with guinea pigs that I have succeeded in getting the
684 Experiments
greatest drops in temperature. One of them (Exp. CCXXIX) , kept
for an hour at a pressure of 35 cm., and for an hour more at 25 and
even 22 cm., had a rectal temperature of only 25°, on leaving the
bell. But after a few minutes the temperature rose to 31° and the
animal survived. The, guinea pig of Experiment CCXXVII, whose
respirations furnished the graph in Figure 48, which remained
nearly four hours oscillating between 21 and 11 cm., had a tempera-
ture of only 20°; it is true that he died during the night after the
experiment.
Decompression then is in itself a cause of a drop in body tem-
perature. In balloon ascensions, this cause is added to the direct
action of an extremely low environmental temperature. In moun-
tain journeys, these two causes take on a more serious importance
because of the expenditure of energy required by the ascent. It is
within these limits that the idea of Lortet can a priori be exact;
but the decompression certainly must hinder the internal oxidation
from acting as it would at normal pressure; no one will ever have
mountain sickness from climbing a hill 1000 meters high, even if
he were loaded with the heaviest burdens.
5. Development. I think I should report here an experiment
which shows that the development of chrysalises is considerably
impeded by lowering the pressure.
Experiment CCXLVII. June 23. Silkworm cocoons, within a day
of the same age, sent from Alais by M. Raulin, are placed:
A. 12 in a bell open above, and consequently at normal pressure;
B. 18 in a bell of 3.2 liters, at a pressure of 50 cm.;
C. 18 in a bell of 7 liters; pressure of 38 cm.;
D. 18 in a bell of 13 liters; pressure of 25 cm.;
E. 5 in a bell of 6 liters; pressure of 5 cm.
Bell D is broken June 25; the water of the hydraulic seal enters
with the air; it is left unchanged. Every other day the air is changed
in bells B and C; every day that in bell E is changed.
July 8, the experiment is stopped, everything is thrown open to
the air, and the cocoons are opened.
The cocoons of A and D have been open since morning; the moths
have issued.
Of the chrysalises in B, 3 are metamorphosed, but the moths have
remained in the cocoon.
The others show considerable signs of life but are not metamor-
phosed.
Those of C show some signs of life, but are not metamorphosed.
The cocoons of E are not opened.
July 15, 3 more chrysalises in B are metamorphosed; but all are
dead.
Symptoms of Decompression 685
C: all are dead too; but under the case of the chrysalis, meta-
morphosis is already far advanced.
D: all dead, with a considerably lower degree of development.
It would be interesting to make experiments with the eggs of
frogs, the larvae of insects, etc.
6. Lower limit of pressure.
The degree of decompression at which the different symptoms
I have just enumerated occur, that of the lower limit incompatible
with life, varies according to the species. The variation depends
also upon whether the animals remained calm or were restless
during the experiment.
In sparrows, uneasiness generally begins to appear at about a
half -atmosphere. The bird becomes restless; it stops hopping about,
and its breathing becomes more rapid; about 25 cm. it begins to
vomit and waver on its feet; soon it falls, and if the decompression
approaches the fatal limit, it whirls about and jerks convulsively.
We saw above that this limit was ordinarily from 17 to 18 cm.
It may vary, between rather narrow limits, for the same species,
in different animals, even when all the conditions of life appear
quite identical. Here is an experiment in proof.
Experiment CCXLVIII. June 18. 4 sparrows: A, old, vigorous
male; B, C, D, females, in good health; all together in the same cage
for several days. Placed together in a large bell of 30 liters, under a
current of air. A cloth covering the bell keeps them from being
frightened and stirring about unequally; they remain very calm dur-
ing all the first part of the experiment, that is, until they are affected
by the rarefied air.
Decompression begins at 4:45.
At 4:49, pressure is only 38.8 cm.; B and D vomit repeatedly.
At 4:52, pressure 29.8 cm.; A also vomits.
At 4:53, pressure 27.8 cm.; C vomits; D is very sick.
At 4:54, pressure 26.8 cm.; all panting and crouched down, except
C, which is standing on its feet.
At 4:55, pressure 24.8 cm.; all are walking, dragging themselves
this way and that, except that A remains motionless, its beak on the
floor.
At 4:56, pressure 23.8 cm.; A is evidently the sickest; then come
D, then B, and finally C, considerably better than the others.
At 4:58, pressure 21.3 cm.; A and D seem dying; they have fallen
over, panting and in convulsions.
At 4:59, pressure 20.3 cm., then the cocks are opened wide; A and
D remain for some time on their backs, and do not recover until
after the others.
At 5:30, all are well.
They survive.
686 Experiments
I have shown that it is possible, with suitable precautions, to
reach 10 cm. (Exp. XXXIX) , a limit which agrees with that indi-
cated by the calculation for the minimal pressure of oxygen. This
limit must be reached very slowly. On the other hand, if the drop
is sudden, the symptoms appear much sooner, and for example,
death occurs suddenly between 25 and 30 cm. The same thing is
true when the animal struggles.
Inversely, it often happens that an animal which appears very
uneasy, near death, under a very low pressure, recovers, gets up,
and becomes fairly well accustomed to it.
All these data, which complicate the numerical solution of the
problem, agree perfectly with the observations of mountain travel-
lers and with what we know of the conditions of asphyxia.
The more carefully the transitions are managed, the more easily
the experimental animals become accustomed to them; the greater
the consumption of oxygen, the more quickly the effect of its lack
will be noted. Travellers, like birds under decompression, like
asphyxiated animals, in a general way, suffer more in proportion to
their activity; we have had many examples of travellers being
forced at certain heights to stop in order to become accustomed to
conditions, and to lie down in order to lessen the consumption of
oxygen. The data I have given agree with this perfectly.
Add that, after a certain number of experiments, summarized
in Table II, the resistance is considerably less when the tempera-
ture is very low. This is an important consideration, for travellers,
like aeronauts, are generally exposed to this depressing condition.
Now nothing is more natural than that the consumption of oxygen
should be increased by the cold, if the temperature of the body is
not to be considerably lowered.
Different species. If we consider the average resistance pre-
sented by the different species, we find that in birds, birds of prey
appear almost as sensitive to decompression as sparrows. This is a
strange fact, when we consider the considerable atmospheric
heights reached by the large birds of prey.
The following experiment, if we compare it with the preceding
one, made the same day, gives a clearer proof than those taken
from Table IV.
Experiment CCXLIX. June 18. Gull (Larus ridibundus Lin.)
and hawk (Falco tinnunculus Lin.).
Decompression was made in the same conditions of speed as for
the sparrows in Experiment CCXLVIII. I summarize in the follow-
ing table the phenomena presented by the three species under the
same pressure.
Symptoms of Decompression 687
Pressure Hawk Gull Sparrows
38.8 cm B, D vomit
34.8 cm Vomits B, D vomit
31.8 cm Staggers, vomits B, D vomit
29.8 cm Staggers, vomits A vomits
27.8 cm. Vomits Staggers, vomits C vomits; D very-
sick.
20.3 cm. Lying down, very sick. Lying down, sicker
than the hawk. A and D dying.
18.8 cm. Lying down, very sick. Dying; cock opened Cock opened
17.8 cm. Dying; cock opened.
And so the hawk is hardly more than a centimeter ahead of the
gull, and two or three ahead of the sparrows. It would be very
interesting to run an experiment not merely on a zoological repre-
sentative of the high-flying birds of prey, but on one of these
birds itself, a condor, for example; unfortunately, physiologists are
not likely to have such luck.
Among the mammals, cats seem almost as susceptible as spar-
rows. They are certainly more so than dogs, for whose death the
pressure must be lowered to 10 or 8 centimeters. Furthermore we
have seen in the historical part that cats are hard to raise at high
altitudes and even die soon there.
Guinea pigs and rabbits are very easy to bring to low pressures,
and since their temperature drops very quickly, they reach the
state of cold-blooded animals, so to speak.
New-born kittens are nearly in this state; and so they die a little
later than adults.
I had hoped, by subjecting to decompression an animal which
hibernated, to bring it to very low pressures also, thinking that it
would hibernate, so to speak; but the only experiment which I
tried, on a hedgehog, disappointed me. I could not go below 18
centimeters without the life of the animal seeming immediately in
danger.
Finally I add that, as might have been expected, cold-blooded
animals resist extremely low pressures.
7. Death.
I have shown above that sometimes the animal dies without any
movement, sometimes rises and stiffens violently before dying, and
sometimes has real convulsions. All that, we have seen, depends on
the state of exhaustion of the animal, the time which the experi-
ment has lasted, etc.
Autopsy shows hardly any interesting results. The blood is dark
everywhere, except in the pulmonary veins, where it absorbs
oxygen during the return to normal pressure. It never contains
free gases.
688
Experiments
In mammals, the lungs are sometimes a little emphysematous;
almost always they are ecchymosed in places, sometimes, but
rarely, with real hemorrhage; in other cases, following sudden
decompressions, I have seen them practically carnified, returned
to the fetal state, and sinking in large fragments to the bottom of
the water. When I discuss sudden decompressions, I shall try to
explain this strange phenomenon.
One curious fact is the suddenness with which rigor mortis
appears. I have observed this result carefully in sparrows. If one
cuts off the head of one of these birds, rigor mortis does not appear
for about three-quarters of an hour, whereas it comes between 10
and 20 minutes after death in rarefied air.
I shall take as examples a certain number of experiments re-
ported in Chapter I. They give the data for the following table.
Table XIII
Experiment
3
Rigor mortis
Temp, of animal
Observations
E s
° £
U
a
E
H
appeared after
at time of rigor
XIX
76
19°
More than 38 min.
I Head cut off.
XVI
19.7
19°
Less than 25 min.
24° (about) | Lived 1 h. 45m.; calm.
XVII
20.8
19°
Less than 20 min.
31.6° | Died in 2 m. Convuls.
XVIII
27.8
19°
17 minutes
26.7°
Lived 2 h. No convuls.
XX
30.8|20°
15 minutes
20.5°
" 6 h. 53 m. Calm.
XXI
30.3120°
Less than 20 min.
24° (about)
" 4 h. 25 m. Calm.
XXII
26.l|20°
1
Less than 17 min.
34.7°
Died in 6 m. No great
convulsions.
XXIV
30.3|20°
1
Less than 20 min.
27°
Lived 1 h. 31 m.
Agitation.
XXVI
24.2|20.5°
About 15 min.
28° (about)
Lived 2 h. 10 m. Great
agitation and violent
convulsions.
XXVII
24.2|20.5°
11 minutes
27.2°
Lived 1 h. 50 m. Ver>
calm.
Lived 1 h. 4 m.
XXVIII
24.2
20.5°
Less than 20 min.
28° (about)
Agitation.
We see that this is a phenomenon that is absolutely constant
and independent of the speed of death, the quiet or agitation of the
bird, and the degree to which its temperature has fallen.
It does not exist in asphyxia in closed vessels, at normal pres-
sure (except in the conditions of Experiment CCL) and I think it
can be attributed only to the exhaustion of the carbonic acid of the
blood and the tissues, by breathing in rarefied air. We shall see
in Chapter VIII that this exhaustion is real.
Symptoms of Decompression 689
Subchapter II
COMPARISON OF THE PHENOMENA OF DECOMPRES-
SION WITH THOSE OF ASPHYXIA IN CLOSED VESSELS
I have repeatedly stressed the parallel between the phenomena
of decompression and those of asphyxia in closed vessels, a paral-
lel continued even in the smallest details. I did so in the first
chapter, comparing the duration of life of animals in both situa-
tions, under the influence of different conditions. I did so again
in regard to the gases contained in the arterial blood in animals
under low pressures and in those asphyxiated in closed vessels,
when the carbonic acid is removed as it is produced (Chap. II,
Subchap. IV).
The descriptions given by countless authors who have killed
animals by asphyxia agree in every point with the phenomena
which we have just enumerated. The respiratory rate is shown
becoming generally faster at first, then slowing up and appearing
very painful when the animal suffers considerably. The pulse
rate, in its number and strength, has been much less studied. But
the nausea, the frightened movements, the final convulsions in the
circumstances which we have specified elsewhere have all been
noted. If the phenomena of nutrition have not had sufficient at-
tention, we have not forgotten the drop in body temperature, and
M. Claude Bernard mentioned the disappearance of the sugar of
the liver in slow asphyxia.
We must note, however, that in the conditions of asphyxia in
which these experimenters placed their animals, the carbonic acid
was stored up in the surrounding air, without their having deter-
mined the influence exerted by this gas, some denying it com-
pletely, others exaggerating it grossly.
The phenomena relating to the decrease in oxygen absorbed,
and in the carbonic acid and urea excreted by animals breathing
an atmosphere low in oxygen content, have not been studied care-
fully enough up to the present. I do not even know any study re-
lating to urinary excretion, and that lack is easily understood; it
would be exceedingly difficult to keep animals on which such an
experiment could be made for a considerable length of time in
rarefied air that was suitably renewed.
As to the absorption of oxygen, while making several successive
analyses of the air of a bell in which an animal was slowly
asphyxiated, I have very often observed that the animal consumed
690 Experiments
less and less oxygen for equal units of time in proportion to the
progress of the experiment towards its fatal conclusion.
Experiment CLXXXVII furnishes an example of this: here,
carbonic acid was absorbed by potash as it was formed, so that
comparison with pure expanded air is quite legitimate; in the first
two hours the dog had consumed 41 per cent of the oxygen of the
closed sack in which he was breathing, while in the following two
hours he consumed only 36 per cent, the total volume of the sack
being moreover much reduced in consequence of the absorption of
the carbonic acid.
The experiments which will be reported in Chapter VIII (Sub-
chap. II) will give the same sort of evidence. So the lack of oxygen
in the air gives the same result as its expansion.
As to the lowering of temperature, the experiments of Chapter
II, Subchapter IV, give us interesting figures. In Experiment
CLXXXVII, in which asphyxia lasted 4 hours and 45 minutes, the
temperature had fallen from 39° to 34.5°. In Experiment
CLXXXVIII: duration 4 hours 30 minutes; temperature, from
38.5° to 34°. There also the two terms which we are seeking to
compare at present are identical.
If we consider respiratory and circulatory phenomena from
the simple point of view of number of movements, we find the
same general tendency and the same irregularities, in asphyxia
as in decompression.
Figure 53 gives an idea of their trend: the unbroken line gives
the results of Experiment CLXXXVII, the dotted line those of Ex-
periment CLXXXVIII. The oxygen content of the air is inscribed
on the axis of the abscissae. The number of respirations (R) and
of the pulse (P) on the axis of the ordinates, on different scales.
We see that in these graphs is shown, after a phase of uncer-
tainty and irregularity, a period of acceleration in the two types of
movement, followed by a period of sudden slowing up.
In some cases, at the end of life, the heart again begins to beat
rapidly, but its beats are very weak. This occurred in one of the
experiments reported in Subchapter II of Chapter VIII, in which
the beats, after having fallen from 120 to 14 at the moment when
insensitivity of the eye appeared, rose suddenly to 60 for some
minutes, when respiration ceased.
As to blood pressure, it drops slowly at first, then rapidly.
Figure 54, whose graphs relate to Experiment CLXXXVII, shows
the course of the maxima and minima, in proportion to the oxygen
content of the air.
Symptoms of Decompression
691
All these phenomena prove once more that the effects of de-
compression are identical with those of slow asphyxia, or, in better
terms, of breathing an air with low oxygen content.
This identity is indicated again by an interesting coincidence.
The details of the experiments reported in, the present book show
that not only death but also the different symptoms appear in
Fig. 53 — Asphyxia without carbonic acid. Number of heart beats P, P',
and of respiration R, R', in relation to the gradual impoverishment
of the air.
692
Experiments
asphyxia at a degree of oxygen lack and in expanded air at a de-
gree of decompression in which the oxygen tension is identical.
So, in dogs, respiratory disturbances appear in confined air at
about the time when there is only 12 per cent of oxygen; in pure
air, they appear at about the pressure of 43 cm., a pressure which
is met at about 5000 meters altitude; in both cases the oxygen ten-
sion is the same, for 12 x 76 = 20.9 x 43.6. As to serious symptoms,
nausea, etc., the proportion of oxygen in the confined air must
drop to about 8 per cent, or the barometric pressure of the pure
air must be reduced to about 30 cm., which corresponds to a height
of 7300 meters; the oxygen tension is the same in both cases.
Fig. 54 — Maxima and minima of cardiac pressure in asphyxia without
carbonic acid.
Now — new confirmation — , it is at these altitudes approximately
that the symptoms and disturbances which constitute "balloon
sickness" occur in aeronauts, motionless in their basket.
The agreement becomes still more interesting when it concerns
observations on man himself.
The most important are contributed by M. Felix Leblanc,2
who had the opportunity to analyze the air of the mines of Poul-
laouen and Huelgoat, in Brittany, whose treatise contains valuable
information about the sensations of the miners.
The pyrites which are present in abundance in the veins being
worked combine with a part of the oxygen in the air, which is
thus lessened without being tainted at the same time by carbonic
acid or other gases, as happens in confined places.
From the data reported by M. Leblanc we extract the following:
A: In a place where there is only 16.7 per cent of oxygen,
respiration is only slightly affected, but the air is considered
"weak" by the miners;
Symptoms of Decompression 693
B: With 15.3 per cent of oxygen, breathing is continuous and
not very difficult.
C: With 9.8 per cent of oxygen, the air is asphyxiating, and at
the end of one or two minutes, fainting fits occur. M. Leblanc,
who went in suddenly, almost fainted, and the master miner who
accompanied him was seized by vertigo and nausea.
Now, in observation A, the oxygen tension equals that existing
in pure air at 60.4 cm. of pressure; which corresponds to a height of
1800 meters. For observation B, the equivalent pressure is 55.3
cm., and the altitude 2500 meters. For C, the pressure is 35.4 cm.,
and the altitude 6000 meters.
It is absolutely certain that a dweller in the plains, suddenly
transferred to heights of 1800 and particularly 2500 meters, and
driven immediately to the hard work of miners, would, like them,
find the air weak and breathing rather difficult. It is absolutely
certain that an aeronaut who was transferred to a height of 6000
meters as suddenly as in the observation of M. Leblanc and who,
like this chemist, tried to make the effort necessary to climb a
slope and empty a flask full of mercury, would also experience
decidedly serious symptoms.
Finally— the last resemblance to which we shall call attention
—the strange rapidity with which rigor mortis appears in animals
dying in rarefied air is found also in death by asphyxia, when the
carbonic acid formed is eliminated by absorbing it with potash.
Example:
Experiment CCL. March 20. At 3 o'clock, a finch is placed under
a bell of 3 liters on a tripod which isolates it from a crystallizing pan
full of a potash solution. An elbow tube connects this bell with an-
other which rests on the water basin, and in which the water will
rise proportionately with the absorption of CO., so that the pressure
will always remain the same.
At 4 o'clock, the bird, which was a little uneasy at the beginning,
lies down and remains quiet; pants.
It dies at 6:23; rectal temperature 31°.
Rigidity begins in the wings at 6:34; it is complete at 6:45.
Our parallel between the symptoms of decompression and those
of asphyxia is therefore complete, and continues even to the least
details with remarkable precision.
In both cases, the whole thing is summarized in this formula:
nutritional disturbances due to the introduction into the organism
of an insufficient quantity of oxygen in a given time.
694 Experiments
Subchapter III.
MEANS OF AVERTING THE SYMPTOMS OF
DECOMPRESSION
The numerous data now enumerated have shown very clearly
that the symptoms of decompression are due, not to the lessening
of atmospheric pressure, but to the diminution of the tension of
the oxygen, which no longer enters the blood, or consequently the
tissues, in sufficient quantity to maintain the vital combustions at
their normal rate. The preventive measures for these symptoms
are naturally derived from this very idea.
The tension of a gas, we have often said already, is expressed
by the product P x Q, in which the barometric pressure P is multi-
plied by the percentage of Q of the gas in the surrounding mixture.
If then we increase the factor Q at the same time that we diminish
factor P by the use of the pneumatic pump, there will be no
change in the tension, and the symptoms should be averted. At
the same time, if the result justifies our expectations, the theory
which serves as the base will once more be verified.
But the experiment, under the form I have just indicated, is
very hard to carry out. We reach the same conclusions by ex-
ecuting it in the conditions of the experiment whose details I
shall now give.
Experiment CCLI. April 23. Sparrow, under a bell of 1.5 liters,
on the plate of the pneumatic machine. Outside pressure is 75 cm.
3:20, brought in a few minutes to 25 cm. pressure; respiratory
rate 212.
At 21 cm., whirls, falls head over heels, about to die. I restore
normal pressure by admitting air very rich in oxygen (by accident,
outer air enters at the same time) ; the bird recovers immediately and
seems lively and well.
3:30, the air then contains 35 per cent of oxygen. I bring the
bird to 18 cm. pressure; he is then very sick, with a respiratory rate
of 176; I admit oxygen again, he recovers immediately.
3:40, the air contains 77.2 per cent of oxygen. The bird under
13 cm. pressure has a respiratory rate of 168, but he falls only at
10 cm. Likewise recovers immediately after the admission of super-
oxygenated air.
3:50, the air contains 87.2 per cent of oxygen. The sparrow, at
10 cm., has a respiratory rate of 176, and seems in no danger; but
at 8 cm., he falls on his back and is about to die. New admission of
oxygen, recovers again.
4:05, the air contains 91.8 per cent of oxygen. We continue to the
Symptoms of Decompression
695
pressure of 7.5 cm.; the bird is very sick, and we have barely time
to open the cocks.
The minimal tensions of oxygen have been successively 5.8; 6.3;
10; 9.2; 9.1.
The bird survives.
And so dangerous decompressions have become successively
harmless, because the percentage of oxygen in the air has been
sufficiently and progressively increased. We reached 12.5 cm. be-
fore the symptoms which announce imminent death reappeared,
and we saw a bird survive after having undergone the pro-
digiously low pressure of 7.5 cm. I do not doubt that we could go
even farther if we proceeded slowly enough.
I have often repeated in public this very simple experiment,
which can be carried out in all physics laboratories, and which is
at the same time very conclusive and very impressive. Figure
55 shows the experimental set-up.
By itself, it would be enough to bring conviction; but to in-
crease the convincing effect, one can complete it by the following
crucial experiment.
Fig. 55— Bird in air increasingly expanded and increasingly oxygenated.
A. Bell-jar communicating at B with the pump, at C with a
barometric tube, at D with a bag full of oxygen O.
696 Experiments
Experiment CCLII. April 24. Under a bell of 2.5 liters, placed
on the plate of the pneumatic machine, and previously filled with
air very rich in oxygen, a sparrow is placed. Outside pressure 75 cm.
The air then contains 82.2 per cent of oxygen; the pressure is
lowered. At 5:30, the pressure is only 13.5 cm.; the bird is uneasy
and flutters in the bell. At 9.5 cm., it is very sick and about to die.
Air somewhat superoxygenated is admitted. The bird recovers im-
mediately.
5:38, the air contains 55.7 per cent of oxygen; we begin to lower
the pressure again, without being able to go lower than 11 cm. Air
somewhat superoxygenated is admitted; bird quite recovered.
5:45, the analysis of the air has been lost. In the decompression
we reached only 13 cm. This time too, the bird is so sick that it re-
mains some seconds motionless on its back after normal pressure is
restored with ordinary air.
5:55, the air contains only 22 per cent of oxygen; so that we
cannot pass below 18 cm.
6:05, this time we use ordinary air; at 20.5 cm., the bird is very
sick; but he recovers perfectly under normal pressure. He has a
large bloody spot on his head.
The oxygen tension at the moment when pressure had to be
restored was successively 10.7; 8.0; 5.0; 5.6.
This last experiment can be made still more simple.
Experiment CCL1II. June 5. Green grosbeak (Fringilla chloris
Lin.). Put under the bell of the pneumatic machine.
Pressure slowly decreased; sick at 30 cm. of actual pressure, and
as it stirred about somewhat, was quite sick at 22 cm.
I then let pure nitrogen enter the bell to restore normal pressure.
The bird, far from recovering, dies almost immediately.
It has in the cranial diploe a huge dark effusion.
Whatever the operative procedure used, these different experi-
ments show clearly both the cause of the symptoms resulting from
decompression and the means of averting them.
Evidently I could not limit myself to experiments made on
animals, however convincing, when I was issuing practical precepts
intended for mountain travellers and aeronauts.
I resolved to begin by experimenting on myself. I had already
undergone, in my large sheet-iron cylinders, rather considerable
decompressions, to the point of experiencing certain discomforts.
I then thought of trying the test again, so as to remove the symp-
toms by breathing a superoxygenated air.
I placed beside me in the apparatus a large rubber bag, con-
taining air whose oxygen content was in proportion to the degree
of decompression. Figure 56 shows the set-up of the experiments.
I give here the details of three of them, and of a fourth which
Symptoms of Decompression 697
was carried on by my regretted colleagues and friends, MM.
Croce-Spinelli and Sivel.
Fig. 56 — Respiration of superoxygenated air, expanded by decrease of
pressure.
Experiment CCLIV. February 20, 1874. Outside pressure 758 mm.
2:30, I enter and seat myself comfortably in the cylinders, hav-
ing with me a bag filled with air extremely rich in oxygen; beside
me, a sparrow in a cage.
. My pulse rate is 64; my temperature taken under the tongue
with great care is 36.5°; an expiration in a Hutchinson spirometer
gives me a value fixed on the arbitrary scale as 17.3.
2:37, the door is closed, the decompression begins.
2:45, pressure 710 mm.; pulse 68.
2:58, pressure 590 mm.; pulse, 70; I am at a decompression cor-
responding approximately to the elevation of Mexico, 2150 meters.
3:02; 535 mm.; pulse, 73.
3:06; 500 mm.; intestinal gases escape.
3:08; 465 mm.; pulse, 78.
3:12; 450 mm.; pulse, 84; it is the barometric pressure of Cala-
marca, at 4150 meters; I have slight nausea.
Experiments
3:14; 450 meters.; pulse drops to 80; nausea disappears; the ab-
domen is slightly distended; my face feels congested and I have
slight dizziness .
3:17; 430 mm.; pulse, 84. I breathe oxygen three times; my pulse
falls to 78; dizziness.
3:21; pressure is only 418 mm.; which corresponds to the eleva-
tion of Mont Blanc, 4800 meters; my pulse rate continues to drop
after some breaths of oxygen; it is only 70; at each respiration, dizzi-
ness.
3:23; 420 mm.; I rise breathing air; my pulse rate rises im-
mediately to 96, then to 100; I have outright vertigo; I sit down
again.
3:25; 445 mm.; pulse rate drops to 90, then after a breath of
oxygen, to 70, at 3:26, at a pressure of 460 mm.
3:28; 450 mm.; the bird falls in its cage.
3:30; 440 mm.; pulse, 76; belching of gas.
3:32; 435 mm. Wishing to raise my right leg without leaving my
chair, it was seized with convulsive trembling in the muscles of
the calf and thigh, a trembling which I could not control with
my hand; it ceased when I placed my foot firmly on the floor; tem-
perature under the tongue is 36.8°.
3:34; 443 mm.; pulse, 80; a breath of oxygen.
3:35; 445 mm.; pulse rate falls immediately to 70; trying to
whistle at this moment, I note that it is impossible.
3:37; 436 mm.; pulse, 80.
3:39; 430 mm.; I breathe into the spirometer; dizziness; I am now
only 11.8 (on the arbitrary scale mentioned above).
3:43; 435 mm.; pulse, 80.
3:45; 423 mm.; pulse 90. I take several breaths of oxygen; dizzi-
ness.
3:47; 423 mm.; pulse rate has fallen to 69.
3:48; 423 mm.; I move about on my chair; slight dizziness.
3:49; 425 mm.; pulse 78.
3:50; 420 mm.; pulse 86.
3:51; 418 mm.; pulse 87; I take a breath of oxygen.
3:53; 426 mm.; pulse 78.
3:55; 430 mm.; pulse 80; some breaths of oxygen; dizziness.
3:57; 430 mm.; pulse 72.
3:59; 420 mm.; pulse 84. I am quite uncomfortable; having found
that the number of my heart beats for 20 seconds was 28, I have
very great difficulty in multiplying this number by 3, and I write
in my notebook "hard to calculate."
4:01; 413 mm.; pulse 88.
4:03; 408 mm.; pulse 92; painful nausea; dizziness; congestion in
the head; convulsive trembling when I raise my leg.
4:04; 415 mm.; pulse 90; I breathe oxygen; dizziness.
4:05; 416 mm.; pulse only 75.
4:07; 420 mm.; I breathe into the spirometer, and go only to
9.9; dizziness and vertigo after having breathed.
4:09; 430 mm.; temperature under the tongue, 36.7°.
Symptoms of Decompression
699
4:14; 445 mm.; pulse 78; I take three breaths of oxygen; dizziness;
the pulse rate falls at once to 63.
4:18; 452 mm.; pulse 79; five times I take breaths of oxygen, each
separated by two breaths of air.
4:20; 450 mm.; the pulse has gone down to 63. The bird, thrown
into the air, falls whirling, and lets itself be caught in the hand.
4:24; 465 mm.; pulse 72; I make an effort and rise; the pulse
rises immediately to 84.
4:26; 490 mm.; pulse 72; I take some breaths of oxygen; dizziness.
4:29; 495 mm.; pulse 60.
4:33; 500 mm.; pulse 65; several breaths of oxygen; the pulse
falls to 64; I try in vain to whistle.
4:37; 540 mm.; pulse 69; the bird refuses to fly from above the
cage, but is quite revived.
4:38; 555 mm.; I cannot whistle.
4:40; 590 mm.; pulse 63; I begin to be able to whistle easily
enough.
4:45; 759 mm.; pulse 58; temperature under the tongue, 36.6°.
The interior temperature of the apparatus has not varied.
In this first experiment, the breaths of oxygenated air were
intermittent, and the effect of each appeared immediately. Nausea
Fig. 57 — Sudden modifications in the pulse rate by intermittent respira-
tions of superoxygenated air. Upper graph, progress of decom-
pression; lower graph, pulse rate; O, inspiration of oxygen.
700 Experiments
disappeared and well-being was restored immediately. The pulse
rate— and this is a very exact indication— dropped immediately, to
return soon to its former figure.
The graphs of Figure 57 show very clearly these curious
changes. The hours are marked on the horizontal axis. The upper
graph represents the downward course of the barometric pressure,
with the elevation corresponding to certain decompressions; the
lower graph indicates the variations in heart rate. At every breath
of oxygen, marked O, we see an instant fall of this latter line;
the demonstration is very clear.
Such sudden modifications in the circulatory rhythm must
necessarily have ill consequences; it is to them that I attribute the
dizziness which accompanied each breath of oxygen. I add that on
the evening of this experiment for several hours I felt symptoms
of cerebral congestion which continued to annoy me somewhat.
I wish the reader also to note the muscular trembling and the
strange state of mental weakness from which I suffered on reaching
the pressure of 420 mm., that is, about that of the elevation of
Mont Blanc; with a pencil in my hand, I was almost incapable of
multiplying 28 by 3.
On the ninth of March, the next month, MM. Croce-Spinelli and
Sivel, who were planning ascents to a great height, came to my
laboratory with the purpose of studying upon themselves the dis-
agreeable effects of decompression and the favorable influence of
superoxygenated air.
I can do no better than to reproduce the account which M.
Croce-Spinelli drew up for me immediately, from the notes which
he and M. Sivel took constantly in the apparatus, of phenomena
which they both experienced.
Experiment CCLV. The diminution of pressure went on regu-
larly; in 35 minutes they were brought to 304 mm.; the return to
normal pressure was made in 22 minutes. They therefore re-
mained for 25 minutes below a pressure of 450 mm.
Paris, March 10, 1874.
Sir:
I am transmitting to you the data which M. Sivel and I collected
and the impressions we felt in your decompression bells, March 9,
1874.
Emotion did not appreciably affect these observations, for I think
that none existed in M. Sivel, and it was extremely weak in me during
the whole experiment. The constant preoccupation of observing data
explains that well enough.
The experiment began at 10:31.
Symptoms of Decompression 701
The first moments of the decompression gave rise to no dis-
agreeable impression. At 10:34 at a pressure of 70.5 cm. of mercury
I found a pulse rate of 80 in M. Sivel; and very shortly after, at G8
cm., 92 in myself. At 1:40, pressure 56 cm., the pulse rate of M. Sivel
was 100; mine was also. At 1:44, pressure 51 cm., my pulse was
116, M. Sivel's 108.
Beginning with a pressure of about 48 cm., oppression begins
to be quite perceptible. I become lazier and am satisfied with con-
sidering what effects I feel. My face feels hot, and so does M. Sivel's
at a pressure of about 44 cm. Besides, I have prickly sensations in
my head, an itching which feels like a scalp affection. Mental energy
is not at all weakened, for we are gay and talkative.
At 1:40, about 41 cm., M. Sivel breathes oxygen from the bag,
not from necessity, but to lessen the considerable tension of the con-
tainer, which is ready to burst. At a pressure of 40 cm., I feel un-
comfortable, my head seems to be in a vise, and I feel as if I were
pressing my forehead hard against a bar of small diameter. My pulse
rate is 135.
At 1:57, at a pressure of 39 cm., I breathe some gulps of oxygen
from the bag which M. Sivel holds out to me. I feel better and my
pulse rate falls to 128, although the decompression is continued.
We pass each other the oxygen bag. My companion uses it un-
til the maximum decompression, 5 or 6 times, often very freely, and
I do 3 or 4 times, in a way that is generally more moderate and
even awkward, for, feeling at first a certain distaste for breathing
this gas which smells of rubber, I lose a fairly large quantity of it.
However, as the pressure lowers, I overcome this repugnance more
easily, and feel instinctively the necessity of absorbing this gas. At
38 and 37 cm., my pulse rate is 128 after breathing oxygen; at 35
cm., it is 132. It is certain that if oxygen were not inhaled, it would
be higher.
In M. Sivel, the absorption of the oxygen produced the follow-
ing effects: the bell seemed to him to be moving as if he were drunk,
and this effect lasted for several seconds; he had a slight sensation
of seasickness. Then this discomfort vanished and his mind became
keener than before the oxygen was inhaled.
In me, the same impressions were present, but in a greater de-
gree. Moreover, below 35 cm., my vision, which was growing dull,
became very noticeably keener after the absorption of oxygen. I
saw clearly after having seen dimly; the interior of the bell seemed
suddenly to become lighter.
At these low pressures, the mind had become very dull in both
of us, but particularly in me. During the four minutes preceding the
time when we reached 30.4 cm., I could only note down the pressures
which M. Sivel dictated to me very loudly, and the simplest calcula-
tions seemed very difficult to me. I was very deaf and had to have
the pressure figures repeated several times. The air no longer seemed
to conduct sound.
At 11:08, at a pressure of 30.4 cm., neither M. Sivel nor I was
saying a word. However, we had been very gay, very talkative and
active to about 37 cm. It is true, we no longer had any oxygen, and
702 Experiments
this fact caused a sort of instinctive regret in me. M. Sivel's mind
then wavered a bit, and I was in a state of decided prostration. The
weakness, however, had not yet reached such a point that we could
not have endured (with some difficulty, it is true) two or three centi-
meters more of decompression, especially M. Sivel, who throughout
showed himself less affected than I.
During the whole experiment, neither of us noted anv abdominal
distention or pulmonary oppression, which astonished me in myself,
since I have very sensitive lungs. Our faces had finally purpled.
M. Sivel had become deep violet, and I, who am ordinarily pale,
light violet. My right ear was very red.
M. Sivel, having noted my state of great discomfort, asked me
whether I thought that the decompression should be stopped. I
answered yes, because there was no more oxygen. The memory of
this fact did not return to me immediately after the experiment, and
it is only at this moment when I am writing that it becomes very
clear to me.
They stopped the machine then and opened the intake cocks.
Here is the pulse rate noted during the period of recompression: in
me, at 52 cm., 104; at 59 cm., 100; at 66 cm., 96. In M. Sivel, at 62 cm.,
98.
In 7 minutes, we returned to 45 cm., and in spite of the speed of
the rise in pressure, we not only felt no discomfort, but on the con-
trary, experienced a very agreeable sensation, I in particular. It was
not until afterwards that buzzing in the ears began in both of us. M.
Sivel drank some water and ate a little, and twice felt relief when
his ear suddenly became unstopped. I was more sensitive to the
buzzing than he; my ear was unstopped only once, and I had severe
pain. This pain increased at about 70 cm., when the operators, seeing
on the outer manometer only a few centimeters of decompression left,
opened the intake cock wide. That probably caused the earache which
persisted in me after the experiment.
On leaving the bell at 11:30, after a 59 minute experiment, I felt
as if there were cotton in my ears, tightly wedged in, but I was not in
pain. My head was free, but my mind a little feverish. All day I felt
my ears, especially the right one, very dull. In the evening the right
ear ached. I went to bed at 11, but could not get to sleep till 4 in the
morning. I had not only twinges and a neuralgia in my temples, but
the inner ear seemed swollen, and a pressure of the hand caused pain.
I soothed the pain by wrapping my head up. As for M. Sivel, this
experience left him no ill effects.
I should say that my "bell companion" is of a sanguine tempera-
ment, that he enjoys excellent health, and that he has a very
vigorous appearance. He is used to long journeys, on land and sea,
and he has made two balloon ascensions. Although of a good consti-
tution, I am evidently less strong than he. I have a "lymphatico-
nervous" temperament.
It seems a good idea to compare the sensations felt in the bell
with those I experienced in the ascent to 4600 meters, under a baro-
metric pressure of 429 mm., in the company of MM. Jobert, Penaud,
Dr. Petard, and Sivel. In this ascent, I felt no disagreeable sensation
Symptoms of Decompression 703
caused by the decompression, nor did my companions. Now in the
bell, about 50 cm., my face prickled, and M. Sivel had the same sensa-
tion at 44 cm. Before 429 mm., the discomfort was already very
considerable, and I had the feeling of a bar across my forehead,
whereas there was nothing of the sort during the ascension. In the
bell, my pulse rate was 116 at 51 cm., 135 at 40 cm., and in the basket
of the balloon, it was 116 between 43 and 44 cm. The pulse rate of M.
Sivel was 108 at 46.5 cm. in the bell, and 110 at 43 cm. in the basket.
I noted the ear buzzing in the ascension exactly as in the bell.
As the balloon descended, it seemed as if there were cotton in my ears.
This impression lasted till the next day, but the pain was never more
than very slight. As in the bell, the pain increased during the last
centimeters of recompression, because of the rapidity of the descent.
In this experiment, the two aeronauts went to a pressure of
304 mm. of mercury, corresponding to an elevation of 7300 meters.
They were, consequently, much more greatly affected than I had
been, not having passed 418 mm., an elevation of 5100 meters;
nervous phenomena dominated the scene in them; dimness of
vision, . intellectual indolence were very noticeable in M. Croce-
Spinelli. M. Sivel, who entered the apparatus fasting, began to eat
during the decompression; he soon stopped, and as I signed to him
through the glass portholes to continue, he replied by a gesture of
disgust.
The favorable action of oxygen was also very evident; after
several inhalations the distressing symptoms disappeared. At one
time, at very low pressures, the lips and the right ear (the only one
I saw) of M. Croce-Spinelli had become so purple that I was pre-
paring to open the cocks, when he put the oxygen tube to his
mouth; the effect, that is, the return to normal color, was in-
stantaneous. M. Croce-Spinelli told me when he had left the ap-
paratus, that he resorted to oxygen at that time because he could
hardly see his paper, which suddenly at the first inhalation ap-
peared to him very white, as if he were dazzled.
In these two experiments, oxygen had been used only intermit-
tently, to lessen for some instants the severity of the symptoms of
decompression. I wanted to operate a little differently, letting the
discomforts come on to a certain degree, then breathing super-
oxygenated air continuously, still decreasing the barometric pres-
sure, and seeing what would happen.
Here is the account of two experiments carried on according to
this procedure.
Experiment CCLVI. March 28. I enter the apparatus at 10:55; the
door is closed at 11:04; my pulse rate is 58. Barometric pressure,
761 mm.
704 Experiments
11:10; pressure 715 mm.; pulse 62.
11:20; 580 mm.; pulse 63.
11:23; 535 mm.; pulse, 63; slight nausea.
11:25; 510 mm.; gas escaping above and below.
11:27; 495 mm.; pulse, 66.
11:31; 455 mm.; pulse, 64; nausea; gas escapes, and yet the abdo-
men remains somewhat distended.
11:33; 435 mm.; pulse, 70; act of whistling, which I manage very
well at normal pressure and which had become difficult at 520 mm.,
is completely impossible.
11:35; 425 mm.; pulse, 72; a little trouble with vision, which is less
clear.
11:37; 412 mm.; pulse, 76; I am quite uncomfortable, with my eyes
somewhat affected.
I begin then to inhale continuously from the bag full of super-
oxygenated air which I have beside me; the exhaled air goes outside.
Occasionally I am dizzy, then every symptom disappears, and until
the end of the experiment, I am in a state of perfect comfort.
The pulse rate, which had fallen instantly to 63, is still falling,
although the decompression progresses.
11:41; pressure, 408 mm.; pulse, 60.
11:46; 382 mm.; pulse, 63.
11:47; 380 mm.; gas escapes by the mouth and anus; perfect com-
fort.
11:48; 369 mm.; pulse, 58; more gas.
11:51; 355 mm.; pulse, 59.
11:52; 350 mm.; more gas.
11:55; 338 mm.; I make efforts to open and close a flask; the pulse
rises to 63; pressure begins to rise again.
11:59; 400 mm.; pulse, 60.
12 (noon); 440 mm.; impossible to whistle.
12:02; 490 mm., pulse, 60; impossible to whistle; I stop breathing
superoxygenated air.
12:03; 520 mm.; impossible to whistle; pulse, 56.
12:05; 540 mm.; I begin to be able to whistle.
12:07; 570 mm.; I whistle very well; pulse, 59.
12:10; return to normal pressure; pulse, 52.
This experiment shows very clearly that continuous inhalations
of oxygen, after having checked painful symptoms, prevent them
from reappearing, although the barometric pressure continues to
fall. Nothing is more conclusive. The decompression reached was
338 mm., corresponding to the elevation of about 6500 meters, that
is, a little more than that of Chimborazo.
Figure 58 shows the different phases through which the heart
beats passed before and during inhalations of oxygen, whose begin-
ning is marked by 0.
Among other phenomena which continued in spite of the in-
haling of oxygen, because they depend entirely upon the decrease
Symptoms of Decompression
705
of the density of the air, I shall mention the evacuations of gas and
the inability to whistle, which had already been noted in the pre-
.5 u
™ tuo
ft X
o
T3 O
o 3
ceding experiment, but of which neither aeronauts nor mountain
climbers speak; it was observed below 500 mm.
706 Experiments
The following experiment, conducted in the same manner, is
even more striking because of the enormous decompression to
which I subjected myself without harm.
Experiment CCLVII. March 30. I enter the apparatus at 10:15;
pressure 759 mm. I have with me a sparrow, whose rectal temper-
ature is 41.9°, a rat, and a candle.
10:22; they close the door; pulse rate, 60.
10:29; pressure 710 mm.; pulse, 63.
10:34; 665 mm.; pulse, 64.
10:40; 640 mm.; pulse, 65; I see bubbles of gas appearing in the
water I have beside me in a glass.
10:43; 605 mm.
10:46; 580 mm.; pulse, 66.
At 555 mm., I whistle easily enough; the flame of the candle grows
rather blue, the wick lengthens; it is almost half the length of the
flame.
At 510 mm., impossible to whistle high notes.
10:53; 480 mm.; pulse, 70; a little discomfort.
10:55; 455 mm.; pulse, 78; a feeling of congestion in the head; gas
escaping above and below.
10:58; 430 mm.; pulse, 80; the bird vomits, appears quite sick,
but remains perched; the rat seems quite calm.
11:00; 410 mm.; pulse, 86; I place before my mouth the tube of
the oxygen bag, which the decompression has distended, and breathe
a very highly superoxygenated mixture; dizziness.
11:02; 400 mm.; pulse has dropped to 64; the bird vomits again;
the rat seems very uneasy.
11:05; 378 mm.; pulse, 66; impossible to whistle.
11:09; 360 mm.; pulse, 72; a little discomfort, although I have
breathed oxygen continuously, but at a distance, it is true. I then
take the discharge tube in my mouth, without closing the nostrils, and
keep it there until the end of the experiment. The discomfort dis-
appears immediately.
11:11; 348 mm.; pulse, 66; the sparrow's respiratory rate is 126.
11:14; 323 mm.; pulse, 64; the sparrow, which is vomiting hard,
nevertheless remains on its perch.
11:17; 310 mm.; I have a little discomfort, with a pulse of 75.
11:19; 300 mm.; the sparrow is very sick.
11:22; 295 mm.; pulse, 64; my discomfort has entirely disappeared.
11:24; 288 mm.
11:27; 280 mm.; pulse, 66; the flame of the candle is very blue; the
wick is about % the length of the flame.
11:33; 258 mm.; pulse, 70; the bird vomits and seems extremely
sick, but it still remains on its perch.
11:34; 255 mm.
11:36; 248 mm.; pulse, 64; I let the pressure increase.
11:38; 290 mm.; pulse, 63.
11:40; 340 mm.; the rectal temperature of the sparrow is only
36.4°.
11:43; 390 mm.; pulse, 54; I stop breathing oxygen.
Symptoms of Decompression
707
11:44; 420 mm.; impossible to whistle; the bird is still very sick,
crouching on its perch.
11:46; 480 mm.; impossible to whistle.
11:47; 550 mm.; still impossible to whistle; pulse, 66.
11:48; 580 mm.; I can whistle the low notes, but not the high ones.
11:49; 630 mm.; I can whistle very well.
11:51; returned to normal pressure; pulse, only 52. The rectal
temperature of the sparrow is 36.1°; that of the rat, 34°; my tempera-
ture under the tongue is 36.5°.
At 3:30, the sparrow's rectal temperature is still only 38.7°.
Here is an experiment in which in an hour and a quarter I
reached a minimum pressure of 248 millimeters, that is, less than a
third of normal pressure, during which experiment I remained 45
minutes below 400 millimeters, without having experienced dis-
comfort from the moment when I began to breathe the super-
oxygenated air regularly. My pulse, as the lower graph in Figure
59 shows, remained from then on at its normal figure; it even
dropped towards the end, either because of the long rest in a
seated posture, or under the influence of breathing superoxy-
genated air. Beside me, a sparrow and a rat were very sick, and
™~1
70 -
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60 —
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V
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40 —
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70
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Fig. 59 — Modifications in the pulse rate, during decompression, by contin-
uous breathing of oxygen. (Exper. CCLVII.)
708 Experiments
their temperature dropped several degrees. As for me, far from
running any risk, I felt none of the slight discomforts of decom-
pression, nausea, headache, or congestion of the head, nor did I
feel any after leaving the apparatus. It even seemed to me as if I
could have gone lower yet, with no inconvenience, and I was
quite ready to do so, had not my steam pumps, weary with work,
refused to continue exhausting the air of the cylinders. Perhaps I
must blame the complicity of the people witnessing the experiment,
who frequently came and looked at me through the portholes and,
in spite of the quite natural appearance of my face, seemed
greatly terrified at seeing me exposed to this enormous diminution
of pressure. In fact, it corresponded to more than 8800 meters,
that is, an elevation greater than that which mountain travellers
and aeronauts, except MM. Coxwell and Glaisher, have ever been
able to reach. I felt no discomfort at this pressure which was
nearly fatal to the two brave Englishmen, and at which a few
months later MM. Croce-Spinelli and Sivel were to perish.
1 See his experimental researches on the physiological properties and the uses of red blood
and dark blood. Journal dc la physiologic de I'homme et dcs animaux; 1858, p. 90, 101, 105.
3 Recherches sur la composition de I'air de quelqucs mines (Annates de chimie et de
physique, Third series, vol. XV),
Chapter IV
ACTION OF COMPRESSED AIR
ON ANIMALS
Subchapter I
TOXIC ACTION OF OXYGEN AT HIGH TENSION
The experiments reported in Chapter I, Subchapter II, have
brought us to this remarkable conclusion, that compressed air, or,
to speak more exactly, the oxygen which has reached a certain
tension constitutes a dangerous element, often even fatal, for ani-
mal life.
This unexpected revelation, which is deduced from all our
series of experiments in such a way as to be convincing to the
most suspicious mind, deserved deep study. The symptoms of this
unknown sort of poisoning in its different degrees had to be
analyzed; the concentrations at which oxygen becomes dangerous
had to be determined, both as to its tension in the exterior respira-
tory medium and as to its proportion in the interior respiratory
medium, the blood; an explanation had to be found for its inner
mode of action upon the different anatomical elements.
This new problem left far behind it in scientific interest the
analysis of some modifications in the respiratory and circulatory
rhythms hitherto studied by the authors who gave their atten-
tion to compressed air. I devoted myself to it at the very beginning
with all the concentration of which I was capable. Having demon-
strated successively that compressed air acts only by the tension
of the oxygen which it contains, and that this oxygen can kill
animals rapidly with convulsive symptoms, following the usual
709
710 Experiments
method of physiologists, I had to set aside for the moment the
effects of low concentrations of oxygen, which are hard to esti-
mate, and study first the violent symptoms caused by high concen-
trations. In the first place, I investigated the action of oxygen
under high tension, generally adding to the manometric pressure
a percentage of oxygen sufficient to produce a value much greater
than that in the air which we breathe.
I think it advisable to report here a certain number of experi-
ments which will permit me to give first a description of the symp-
toms resulting from what I shall call, if only for convenience in
nomenclature, poisoning by oxygen.
Already we have noted the convulsions which had attacked
sparrows subjected to this dangerous agent. The following ex-
periments, almost all performed in the Seltzer water apparatus,
will furnish us new examples.
Experiment CCLVIIK January 29. House sparrow subjected to 6
atmospheres, 5 of which were oxygen, from 3:50 to 3:58. The mix-
ture contained 81 per cent of oxygen, and the tension of this gas was
486
therefore equivalent to 81 x 6 = 486, which corresponds to = 23.2
atmospheres of air. 20.9
At 4:03, violent convulsions, the head hanging down; whirling.
I lower the pressure and bring it to 3.5 atmospheres. During the
decompression, new convulsions.
Immediately after, third attack; then new attacks, weaker and
weaker, at 4:06, 4:11, 4:14.
During the attacks, and in the intervals, the respirations are very
deep and very hasty; the beak is wide open.
The attacks come oftener at intervals of 1 to 2 minutes, becoming
weaker and weaker. They subside about 4:40; the bird remains lying
on its back, its respirations become rarer and rarer, and cease at 5
o'clock, without any other movement.
At 5:10, the rectal temperature is 24°.
Experiment CCLIX. February 2. House sparrow, subjected to 6
atmospheres, 5 of which are oxygen. The oxygen tension is about 450.
After 5 minutes, strange tremors, a quivering through the whole
body; then it remains motionless, its beak down.
After 10 minutes, an attack of strong convulsions; another at 12
minutes; a third, weaker, at 17 minutes. The bird is very sick, breathes
from 50 to 70 times a minute, its beak wide open.
Brought back carefully to normal pressure; recovers a very little;
rectal temperature, 34° to 35°. In its cage it has new convulsive
attacks; at the end of a quarter of an hour, gets up on its feet; but
when it is threatened with the finger, it draws back walking on the
whole tarsus, and falls backwards.
Compressed Air; (X Poisoning 711
After 2 or 3 hours, seems fairly well recovered, but dies in the
night.
Experiment CCLX. February 5. Sparrow subjected to 5 atmos-
pheres, 4 of which are oxygen. The oxygen tension is about 400. After
about 15 minutes, strong convulsions occur; I allow 2 or 3 attacks, then
restore normal pressure.
The rectal temperature is 32°.
The bird has evidently retained all its intelligence; it pecks
viciously when a finger is presented to it, and uses its wings and feet
strongly.
One hour afterwards, its temperature is 34°. It has had more of
the slight convulsive attacks, and cannot keep on its feet.
3 hours afterwards, its rectal temperature has risen to 39.5°.
Survives.
Experiment CCLXI. February 26. Sparrow; rectal temperature
40.5°.
Subjected to 5 atmospheres, 4 of which are oxygen (tension of
about 400).
At the end of 5 minutes, beginning of uneasiness. I restore normal
pressure rapidly by the capillary cock.
The temperature is 40.3°, but it rises rapidly to 40.5° after respi-
ration in the air. The bird is very vigorous and very vicious. Red
cranial suffusions, in abundant spots.
The bird walks, runs, climbs about the cage, but does not fly. If
it is tossed into the air, it has great difficulty in flying and soon falls;
it then refuses to fly up from the ground.
Survives; the next day, it flies very well; the suffusions persist for
several days.
Experiment CCLX1I. March 2. Sparrow at 5 atmospheres, 4 of
which are oxygen.
After 5 or 7 minutes, convulsions begin; at the first appearance,
I open the little cock. The rectal temperature rises to 41°, but very
slowly after 38°.
Small bloody suffusions.
Experiment CCLXIII. May 23. At 4 o'clock, sparrow taken to 5
atmospheres, 4 of which are oxygen. Tension about 400.
After 15 minutes, slight convulsions; at 20 minutes, severe con-
vulsions, two or three attacks. At 30 minutes, taken out.
Rectal temperature, 33°.
At 5:45, rectal temperature, 35°; still trembling, quite sick.
At 7 o'clock, dead; muscular contractions singularly slow.
Experiment CCLXIV. February 12. Sparrow; cylindrical appara-
tus.
At normal pressure, respiratory rate, 135. Raised to 3 atmospheres
of air, respiratory rate, 115.
At 4:20, I pass a current of oxygen into the apparatus, and raise
the pressure to 2 superoxygenated atmospheres.
712 Experiments
At 4:30, new ventilation, and pressure raised to 3 atmospheres.
At 4:40, the same; pressure at 4 atmospheres.
At 4:55, the same, 5V4 atmospheres; little convulsions begin to
appear.
At 5:06, new ventilation carried to 6 atmospheres. Convulsions
return, in spasms.
Dead about 6:50.
The air then contained 73 per cent of oxygen and 0.5 per cent of
carbonic acid.
The oxygen tension P x 0-> = 438 corresponds to 21 atmospheres
of air.
Blood very red in the jugular. Bloody suffusions extending over
the whole cranium.
Experiment CCLXV. March 29. Sparrow placed in the small
Seltzer water apparatus.
At 2:50 we begin to compress oxygen up to 8 atmospheres; the
capillary cock being open, the compression maintained is carried on
in a current of air delivering more than a liter per minute.
At 3:15 great convulsions occur; I allow two attacks to succeed
each other, at three minutes interval. Then, rapid decompression. The
bird pecks the finger which I offer it, and appears intelligent.
Its rectal temperature is 32°. When out of the apparatus, it has a
third attack, and dies at 3:22. The blood of the jugular vein is dark
and contains no free gases.
Experiment CCLXVI. July 9. Sparrow taken to 7 atmospheres of
superoxygenated air.
After 10 minutes, seized by tonic convulsions. Taken out after
15 minutes; the convulsions continue, or rather the bird is in constant
opisthotonos. From time to time, the stiffness increases; the bird cries
out, spreads its wings, and wraps itself in them; the tail feathers are
spread out. Remains sensitive and appears intelligent. The attacks of
rigor are some of them spontaneous, others clearly provokable by
stimuli.
It dies 20 minutes afterwards.
Experiment CCLXVII. July 18. Sparrow taken to 5 atmospheres
of superoxygenated air.
After 5 minutes, vomits, and appears in very bad shape. But the
convulsions do not come until about 20 minutes after, and they are
violent.
Taken out 5 minutes afterwards, it continues to have convulsions
and stiffness with opisthotonos. Pecks the finger presented to it. Its
rectal temperature is 37°.
Two hours after, is perfectly recovered; its temperature has risen
to 41°.
Experiment CCLXVIII. May 24, 1874. Experiment made before a
Committee of the Academy of Sciences.
Sparrow taken to 6 atmospheres, superoxygenated. It is 4 o'clock.
After about 15 minutes, slight convulsions occur, soon followed
by severe attacks.
Compressed Air; O, Poisoning
713
The bird is removed; it has large ecchymoses on the cranium.
Its rectal temperature is only 30°.
Remains very sick and dies in the night.
The data which have just been given permit us from now on
to describe the violent symptoms due to compressed air, to too
high oxygen tension, and to prepare the physiological analysis of
this poisoning.
The first question which we should ask ourselves is as follows:
at what oxygen tension do the convulsive symptoms appear?
Let us collect in a table (Table XIV) the experiments of Chapter
I and those which precede.
Table XIV
1
2
3
4
5
6
_
C u
■§!
C
a
Experiment
a
a
u
3
Numbers
t>u
£&
CO
Symptoms and observations
lid
CQ Cu re
Sic
*2
Equiva
atmosp
of air
atm.
CXXXIX
1.75
150
7
No convulsions
CXXXVIII
3
260
13
Id.
CXLI
4
300
15
Convulsions.
CXX
I 20
abt. 420
20
Convulsions; the apparatus leaks.
Convulsions; withdrawn, survives.
CCLX
5
id.
I abt. 21
32°
CCLXI
5
id.
id.
40.2°
Withdrawn after first conv., survives
CCLXII
5
id.
id.
38°
Id.
CCLXVII
5
id.
id.
37°
Id.
CCLXIII
5
id.
id.
33°
Conv.; withdrawn after 30 min., dies.
CXXXVII
5
id.
id..
18°
Violent conv., dies in 25 minutes.
CXLII
8.5
430
21.5
Id.; dies in 20 min.
cclxiv
6
440
22
Id.
CXLV
5.5
460
23
27°
Id.; dies in 20 min.
CCLXVIII
6
30°
Id.; dies during the night.
CCLVIII
6
480
24
Id.; dies.
CCLIX
6
id. (?)
I id.(?)
35°
Id.; withdrawn; dies during night
CCLXV
1 8
32°
Id.; withdrawn; dies at once
We see from an examination of this table that the convulsions
begin to appear with an oxygen tension expressed by the figure
300, which, if we used pure air, would correspond to about 15
atmospheres.
The harmful effects were observed much sooner, as graph A of
Figure 22 shows, which expresses the proportion of oxygen re-
maining in the compressed air in which the birds died, when we
took care to eliminate the carbonic acid formed. The harmful
effects are very clear beginning with 6 and especially with 12
atmospheres.
But the convulsions appear surely only between 15 and 20
atmospheres. Experiment CXX, in which a linnet was taken to
20 atmospheres of air, shows their appearance; only they were
714 Experiments
considerably weaker than those obtained with superoxygenated
air. Furthermore, in Experiment CXXXIII, in which the pressure
was 17 atmospheres, there were no convulsions. This apparent
contradiction is explained by the simultaneous influence of the
carbonic acid produced, which, being stored in the organism, plays
a very pronounced anesthetic part there, as we shall see in a spe-
cial chapter. Now we shall show in a moment that anesthetics
stop or hinder the convulsions due to oxygen.
Let us give now a brief description of these convulsions; we
shall have to return to them when we have studied them in dogs.
These convulsions occur at the end of a variable time, generally
from 5 to 10 minutes; the bird shakes its head and feet as if it
were walking on hot coals. There are strange tremblings, quiver-
ings through the whole body. Soon, in more serious cases, it half-
opens its wings, moves them quickly, and falling on its back, it
whirls rapidly in the receiver, beating the air with its wings
violently, its feet curled up against its belly; these phenomena
last for a few minutes, then grow calm, then reappear in attacks
which are more and more frequent and less and less strong until
death. During the attacks, and in the intervals, the respirations
are very deep and very hasty; the beak is very wide open. At
very high pressures, death comes at the first attack.
These remarkable symptoms continue to appear after the bird,
removed from the influence of oxygen, has been restored to the
open air under normal pressure; they may even then end in death.
These attacks are often very clearly provokable, like those of
strychnine (See Experiment CCLXVI) ; their general appearance
recalls at the same time the irregular quiverings of poisoning by
phenol,1 and the tonic and clonic convulsions of convulsive strych-
nine attacks.
Neither sensitivity nor intelligence seems affected; the bird,
taken from the receiver, looks at and tries to peck the finger
which threatens it; it closes its eyelids when some object approaches
its eye.
General locomotion is evidently much affected, besides the
convulsive attacks, of course; the bird has ataxic movements; in
certain cases, it can hardly stand on its feet; in others, it can
walk, but not fly.
Finally — and this is the most important point of this research,
after the observations of these symptoms — the inner temperature
drops in all cases rapidly and considerably. It falls 10 and 15
degrees; I call particular attention to Experiment CCLV, in which,
Compressed Air; 02 Poisoning 715
although the temperature had fallen to 32° in less than a half-
hour, it rose rather quickly to nearly 40° and the bird survived.
I shall later dwell upon this remarkable fact, to which at present
I merely call attention; it shows very clearly that the symptoms
of oxygen poisoning are not due to an exaggerated activity im-
parted to the intra-organic combustions.
The first idea which would come to mind, and I admit freely
that it came to mine immediately, is that under the influence of
this super-saturation of oxygen the animal tissues would be con-
sumed excessively, that an increase in the temperature would re-
sult, and that the convulsions which appeared could be compared
to those which precede the death of animals over-heated in a
drying-oven. Now we can state immediately that this is not true,
although later I shall analyze this important phenomenon thor-
oughly.
Finally I shall say a few words of a symptom always present
in birds in cases of oxygen poisoning, a symptom which I have
designated by the expression "bloody suffusions of the cranium."
They are hemorrhages which fill the cranial diploe; in the
mildest cases they consist only of very small dots; these dots
are replaced by wide spots which become confluent in severe
cases, and the spongy tissue of the bone fills with blood. They
always begin in the occipital, but may affect the whole cranium.
They appear before the convulsions, and when the bird does not
die, they are not absorbed for several weeks. Although they
always exist when the symptoms due to oxygen become serious,
they are not especially characteristic of this poisoning. Since my
attention was called to their existence, I have found them quite
often in asphyxia and death by decompression. In fact, they were
noted in some of the experiments reported in Chapter I; when
they are not mentioned, it simply means that no one looked for
them. I should add that I never saw them so extensive or so deep
as in oxygen poisoning. I have no understanding of their mech-
anism; they appear without any convulsive phenomenon, and
autopsies have not shown any apoplexies in any other part of the
body.
Let us now analyze a little more deeply the phenomena just
described. Upon what anatomical element does excessive oxygen
act? What is the cause of the convulsions? Is the heart directly
attacked, as it is by such a great number of poisons? The data
which have just been reported would be insufficient to permit
us to reply completely to these different questions.
716 Experiments
We have had to use the best physiological reagent, the frog.
Experiment CCLXIX. February 27. Frog subjected at 2 o'clock to
7 atmospheres, 6 of which were oxygen. The oxygen tension corre-
sponds to 505. In the evening, at 7 o'clock, nothing particular; seems
a little uneasy.
February 28, at 9 o'clock in the morning, dead. No reflex actions
of any sort; the motor nerves and the muscles are excitable. The
heart, of a fine carmine red, beats slowly when exposed. Free gases
in the blood.
The lethal air contains no trace of carbonic acid.
Experiment CCLXX. March 4. Frog subjected at 4 o'clock to 5
atmospheres, 4 of which were oxygen; the tension of this gas is about
300.
At 10 o'clock in the evening, swollen.
On March 5, at 2 o'clock, seems dead. The heart no longer beats
spontaneously, but is excitable; the motor nerves and the muscles are
excitable. By cutting through the spinal cord in the back, movements
in the lower limbs are caused.
Experiment CCLXXI. February 29. Frog subjected at 6 o'clock
to 4 atmospheres, 3 of which were oxygen.
The tension of this gas is 254.
The next day, March 1, at 3 o'clock, it is rigid and swollen, seems
to have convulsive movements when one raps on the table. At 7
o'clock in the evening, is much weaker.
March 2, at 1 o'clock, dead, stiff. The heart beats, the nerves and
the members are excitable; no movement is produced when the spinal
cord is cut.
The lethal air contains no trace of carbonic acid.
Experiment CCLXXII. April 18. Frog subjected at 6 o'clock in
the evening to 4V2 atmospheres of superoxygenated air. The oxygen
tension is represented by 335. Temperature 15°.
The next day, nothing especial in the appearance of the frog.
April 20, found dead at 1 o'clock. The heart, very pink, is still
beating a little. The muscles are perfectly contractile.
Experiment CCLXXIII. June 17. Frog subjected at 4:30 to a pres-
sure of 5 superoxygenated atmospheres. The heart is laid bare,
temperature 20°.
June 18, at 11 o'clock in the morning, very weak, prostrated. No
respiratory movements. Pulsations of the ventricles, rare, irregular;
but the auricles alone beat 40 times per minute.
At 3 o'clock, decompression. A few weak heart beats yet. There
are no reflex acts, but the motor nerves and the muscles are quite
excitable.
Sugar in the liver, in a rather large quantity.
We conclude from all these experiments that oxygen does not
kill by acting on the heart, the motor nerves, or the muscles. But
Compressed Air; 02 Poisoning 717
the reflex acts of the spinal cord,- after being considerably excited,
are checked.
The fact that the convulsions come from the spinal cord, com-
municating its excitation to the muscles by means of the motor
nerves, is abundantly proved by experiments in which the motor
nerve has been cut: Example:
Experiment CCLXXIV. June 20. Frog; left sciatic nerve cut.
3 o'clock in the afternoon; subjected to 3 superoxygenated atmos-
pheres, containing 60.5 per cent of oxygen, 3 x 60.5 = 181.5 = 9 atmos-
pheres of air.
Respiration ceases for a moment.
June 21. Respirations very rare; eyes protruding with widely
rounded pupils; frog is swollen, rather weak; no convulsions.
June 22. 11 o'clock in the morning. No respiration; weak; eyes
closed by the transparent lid. Clonic convulsions beginning in the
right front leg, then becoming generalized, except in the left hind
foot; then general stiffness; then weakness.
These attacks are excitable at will, by shock; but the frog soon
seems insensible, as if dead.
Sudden decompression; no effect. In the outer air, does not
breathe; the heart, exposed, beats 50 times per minute; the blood,
which was red at first, grows progressively darker.
After about a quarter hour, excitation brings on new convulsive
attacks, like the preceding. On exciting the right hind foot, move-
ments of the right front leg are produced, but not of the left.
Frequently fibrillary contractions, in the muscles of the chest
especially and also in the limbs, except the left hind foot.
During the convulsions, the heart does not seem altered.
Dies about 2 o'clock.
So section of a motor nerve prevented all convulsive move-
ment, fibrillary or generalized, from appearing in the correspond-
ing muscles.
Since oxygen injures the spinal cord, like strychnine, phenol,
etc., convulsions should be prevented by chloroform, which, as I
have shown before,2 acts particularly on the spinal cord. In fact,
this very thing happened in the following experiment.
Experiment CCLXXV. February 26. Etherized sparrow, put into
the receiver; rouses during the compression. I put some drops of ether
into the vessel in which the oxygen sucked in by the pump is bub-
bling in the potash, and raise the pressure to 5 atmospheres, 4 of
which are oxygen.
The bird becomes unconscious again, after some quiverings of the
feet; he dies slowly, in 25 minutes, without any convulsion.
Huge cranial suffusions.
The lethal air contains CO, 2; O? 76. The original pressure of the
oxygen was therefore about 78x5 = 390, corresponding to 19 atmos-
pheres of air.
718 Experiments
This experiment shows not only that anesthesia prevents con-
vulsions from oxygen, like those of other poisons of the spinal
cord, but also that it does not prevent death from coming, al-
though it comes calmly. The following experiment, in which the
animal was removed after the action of the oxygen, its convul-
sions appearing gradually as consciousness returned, is still more
convincing.
Experiment CCLXXVI. February 24. Chloroformed rat, nearly
died during anesthesia.
Begins to be sensitive after about a half-hour. Rectal temper-
ature 35°.
Subjected to 5 atmospheres, and after 10 minutes to 6V2 atmos-
pheres of oxygen.
At the end of 20 minutes of compression seems very sick; a few
slight quiverings; the convulsions not appearing, it is withdrawn.
Rectal temperature 34°.
Put back into the cage, remains stretched out; it is soon seized
by convulsions; stiffening of the tail, etc. They appear spontaneously
or as soon as the animal is touched.
One hour after, same condition; temperature 32°.
2V2 hours after, very slight convulsions; temperature 28°. Evi-
dently dying.
February 25. Found dead and cold.
I do not dwell upon this point, because the experiments made
on dogs will give us analogous data.
Before coming to the experiments on dogs, I think I should
report one more which was performed on sparrows, and in which
we see demonstrated the important part played by the blood in
oxygen poisoning.
Experiment CCLXXVIL July 17. Two sparrows are subjected,
from 5:02 to 5:07, to 8 atmospheres of superoxygenated air, in which
the oxygen tension is equivalent to 424, that is, 20 atmospheres of air.
One, A, is in good shape; the other, B, which weighs 20 gm., was
bled at 4 o'clock of 0.7 cc. of blood from the jugular; it is still very
weak; its rectal temperature is only 32°, while A's is 42°.
At 5:10 or 5:12, A shows slight convulsive shivers, and about 5:20
real convulsions, which last until 5:33, when he dies. B is not affected
until 5:25 and then slightly; no general quiverings, but great efforts
in breathing, stiffness, etc., which become true convulsions, of the
feet, if not of the wings, about 5:35; he has a few of them, then
remains on his back as if dead.
Decompression at 5:45.
A, rectal temperature 31°.
B, rectal temperature 28°.
Enormous cranial suffusions on the two birds.
B is still breathing; his rectal temperature drops and is 25° at 6
Compressed Air; CX Poisoning 719
o'clock; he dies then. When the muscles were pinched, they con-
tracted slowly and strongly as if with cramps.
So in the animal which had been bled the symptoms appeared
much more slowly than in the healthy animal. That is the effect
both of the general weakening he had undergone and of the di-
minished quantity of blood, which, since it contained a smaller-
quantity of oxygen, could carry this dangerous agent to the spinal
cord only in smaller proportion.
It would be premature to dwell at this moment on the part
played by the blood in oxygen poisoning. This question will recur
in a much more significant manner when we have studied the
experiments made on dogs, which I shall now report in detail.
When I used dogs as experimental animals, my special purpose
was to investigate the proportion of oxygen contained in the
blood when the convulsive symptoms occurred. I intended also to
continue at the same time, thanks to the use of superoxygenated
compressed atmospheres, the research of the proportions estab-
lished in the living animal between the tension of the oxygen in
the respiratory medium and the oxygen content of the arterial
blood, proportions studied in Subchapter III of Chapter I up to 10
atmospheres of air only.
The experimental animal was fastened on his board as is ex-
plained in the subchapter just mentioned. To succeed in making
him breathe compressed oxygen, I had recourse to a special device,
not having at my disposal the quantity of oxygen necessary to
compress this gas to several atmospheres in a receiver of 150
liters capacity.
I fixed in the dog's trachea a metallic tube as wide as possible,
and connected it with a rubber bag having a capacity of about 30
liters. This bag was placed beside the animal, and the air injected
into the chamber by the pump compressed both the oxygen and the
animal at the same time. The experiment never lasted long
enough for the dog to exhaust the oxygen entirely. But as the
expirations were made into the bag, carbonic acid was stored up
there, which consequently accumulated also in the blood. And so
we should not take account of the proportion of this gas shown
by the analyses; I thought, however, that I should indicate it as
a matter of information in the account of the experiments. In
a certain number of cases, to avoid this accumulation, I attached
to the tube which went from the trachea to the bag, a flask in
which the superoxygenated air bubbled in a solution of potash; in
other cases, the solution was in the bag itself. These experiments,
720 Experiments
compared to those in which no such precaution had been taken,
allow me to state that in the latter the influence of the carbonic
acid was quite negligible; that will be explained naturally, when
we discuss poisoning by carbonic acid in Chapter VIII.
Here now is the report of a certain number of experiments.
Experiment CCLXXVIII. November 16. Black dog, short-haired,
new subject, weighing about 12 kilograms.
It is fastened on its back, and in its trachea is inserted a metal
tube, at the end of which is a rubber tube considerably narrower.
Respiration is carried on in series of extreme frequency, separated
by a few intervals of calm.
At the end of about a half-hour, the rectal temperature is 36°
(in a healthy dog the same thermometer gives 38.5°).
Then from the left carotid 35 cc. of blood is drawn, which is imme-
diately taken to the pump for extracting gases .... A
The dog is next placed in the compression apparatus; to the tube
in its trachea is then fitted a rubber bag containing oxygen; then the
animal is fastened as explained above.
Pressure is begun at 3:56.
At 4:21, the pressure is 5 atmospheres; I draw 38 cc. of very red
blood, not letting gas escape . . . . B
At 4:40, at 7 atmospheres, drew 31 cc. of very red blood, in which
escape of gas is at least doubtful . . . . C
Pressure is raised to 8 atmospheres, and at 4:45 decompression is
made suddenly in 3V2 minutes.
The animal is immediately withdrawn from the apparatus; there
are no free gases in either the arterial or the venous blood; the heart
sounds are normal, without any gurgling indicating the presence of
gas. The rectal temperature is 30°. There has been an evacuation of
fecal matter, and the mouth is full of froth.
The paws are much stiffened; when the animal is unfastened, he is
in very pronounced opisthotonos; the whole body is in tonic convul-
sion. Fecal matter continues to be discharged. The eye closes when
the cornea, but not when the conjunctiva, is touched; the pupils, much
dilated, do not contract in light.
The arterial pressure in the carotid varies between 9 and 12
centimeters.
The symptoms continue to increase in intensity. About 5 o'clock,
the convulsions are extremely violent; in the midst of continuous
stiffenings, there appear clonic convulsions of the limbs, the neck, and
the jaws. The eyes are convulsed. The penis is so retracted that to
catheterize the animal the prepuce has to be slit its whole length; no
urine in the bladder. The animal froths terribly.
About 5:30, the temperature is 29 degrees. Vomiting begins. The
convulsions appear like fits, with no real rest in the interval; it appears
much like successive strychnine attacks, except for the almost com-
plete permanency of the stiffenings and the opisthotonos. Clonic
convulsions are caused by touching the animal, by hitting the table,
Compressed Air; (X Poisoning 721
by inserting the thermometer into the depths of the rectum. During
the attacks, the respiration stops, but the heart continues to beat.
Gradually intervals of comparative repose appear. The animal
begins to grind its teeth with such extraordinary force that one would
expect them to break. The temperature rises again; at 6 o'clock it
is 31°.
6:15; now and then, the stiffness disappears; the respiration is
better; the tail moves.
6:45; the animal is still lying on its side; the clonic convulsions
are like those of phenol, in that they almost imitate the motions of
walking; they follow each other in attacks separated by an interval
of relative repose. At each attack, violent opisthotonos, with quiv-
ering of the jaws, then a snapping of the teeth; from time to time,
general stiffening with motionlessness, the stiffening less than at the
beginning. The pupils are still insensitive to light. The temperature
is 32 degrees. The heart beats hard and fast.
The next day, at 11 o'clock in the morning, the animal, in whose
trachea the cannula has been left, is lying as on the day before; it is
in opisthotonos with permanent contractions of the limbs; the anal
sphincter is closed; weak, but almost continuous quiverings. Viscous
salivation, as well as watering of the eyes, has continued; the pupils
are dilated; the cornea is sensitive, but not the conjunctiva. Respira-
tion quite calm; pulse 80, weak; temperature 27°.
I administered chloroform until the cornea lost sensitivity; the
stiffening and quivering disappear to reappear soon.
The animal dies during the day.
Now here is the result of the analyses:
A: Ordinary air, normal pressure; 100 cc. of blood contain
O, 15.5 cc; CO? 22.9.3
B: 5 atmospheres of superoxygenated air: 100 cc. of blood con-
tain 02 24.0; CO 63.
C: 7 atmospheres of superoxygenated air: 100 cc. of blood con-
tain 02 31.5; C02 54.6.
The air of the bag, after the experiment, contained per 100, O, 66;
CO, 5.4. The original composition was therefore about 75 per cent of
oxygen.
The oxygen tension in B was about 70 x 5 = 350.
In C, it was about 68 x 7 = 476.
It was raised to 66 x 8 = 528, which corresponds to about 26
atmospheres of air.
This experiment is particularly remarkable; here is an animal
which, after being exposed for three-quarters of an hour to an
oxygen tension corresponding to nearly 26 atmospheres of air, died
after about 24 hours of violent convulsions.
Experiment CCLXXIX. November 20. Rather young dog, weigh-
ing about 8 kilograms.
Tube placed in the trachea.
~% After a quarter of an hour, the rectal temperature is 39.4°; pulse
722 Experiments
144, respiratory rate 24; blood pressure in the carotid varies between
15 and 17 cm. of mercury.
At 3:38, drew 38 cc. of blood .... A
Placed in the apparatus at 4: 10, with a bag full of a mixture with
89.5 per cent of oxygen.
At 4:30, pressure is 5 atmospheres, maintained there.
At 4:38, drew 43 cc. of very red blood; no gas escapes . . . . B
At 4:40, decompression in 1% minutes.
The animal is immediately withdrawn, the bag is removed, and
it is noted that it has already vomited in the apparatus. It vomits
again. It shows attacks of stiffening without clonic jerks. The temper-
ature is 36.5°: the arterial pressure from 11 to 12 cm.; pulse is 140,
respiratory rate 24.
These attacks of convulsive stiffening last about 20 minutes.
At 6 o'clock, the temperature is 35°, the arterial pressure 12 cm.,
the pulse 140. The dog begins to be able to stand on its feet.
At 6:30, the animal, whose cannula has been removed, remains
lying down with a sort of muscular trembling, resembling that of
phenol poisoning. Its eyes are sensitive, and the pupils contract and
dilate as if by tremors which are related to the quivering of the
limbs. There are occasional stiffenings of the front feet, but they can
easily be bent.
The next day, in good health.
The analyses gave the following results:
A: Air, normal pressure; 100 cc. of blood contain: O, 17.0; CO:
39.0.
B: 5 atmospheres of superoxygenated air: 100 cc. of blood con-
tain: CX 24.8; CO, 75.0.
The gas in the bag after the experiment contains 76.2 of oxygen
and 8.1 of carbonic acid. The oxygen tension in B was then about
77 x 5 = 385.
Experiment CCLXXX. November 25. Dog of average size.
Tube in the trachea; left carotid exposed.
Rectal temperature 38. IV
3:12; drew 33 cc. of blood; the animal breathes quietly .... A
Placed in the apparatus at 3:55, with oxygen bag; between the
bag and the tube in the trachea a flask is placed, at the bottom of
which are bits of potash; by this means I intend to diminish the
proportion of carbonic acid stored in the bag.
4:25; pressure 7 atmospheres; at 4:28, with great difficulty drew
23 cc. of blood . . . . B
4:38, pressure 7 xk atmospheres; sudden decompression.
Withdrawn at 4:45, the animal's eyes are sensitive; its tempera-
ture is 36°; there are stiffenings of the hind legs and the neck; the
respiration seems suspended, the heart beats very feebly.
After 10 mmutes the stiffenings increase, but the respiration re-
turns, and the heart beats more quickly and strongly. Soon after,
the animal again becomes limp, as it was when it was taken from the
apparatus; its respiration is weak; it dies at 5:50, without moving.
At 5:20, its temperature was 34.5°; at 5:50, it had fallen to 33.5°.
Compressed Air; 02 Poisoning 723
At 5:05, I drew 33 cc. of blood from the carotid . . . . C
At 5:30, drew 33 cc. of blood also from the carotid . . . . D
The autopsy shows the heart full of dark blood on the right, a
little red on the left. There are in the bladder some drops of urine
with an exceedingly high sugar content. The liver contains much
sugar.
Blood A (air, normal pressure) contained . . O, 14.4; C02 41.0
Blood B (oxygen, 7 atmospheres) contained . . O, 24.1; C02 68.5
Blood C (air, normal pressure, 40 min. after decompression) con-
tained . . O, 15.8; CO, 16.5
Blood D (air, 70 min. after decompression) contained O, 15.8;
C02 28.3
The gas in the bag contained before the experiment 79 per cent
of oxygen; the oxygen tension in B was probably 74 x 7 = 518; it rose
to a maximum of 550 at 4:38.
Experiment CCLXXXI. November 27. Shepherd dog, weighing
16 kilos.
Tube in the trachea; rectal temperature 38.5°.
At 4:50, drew 33 cc. of blood from the left carotid A
Placed at 5:08 in the compression apparatus with the oxygen
bag, without the potash flask.
At 5:12, pressure is 1% atmospheres; drew 33 cc. of blood, very
red B
At 5:48, 7 atmospheres; this pressure maintained, and at 5:50,
drew 39 cc. of very red blood, without free gases C
At 5:53, decompressed in 2 minutes.
Withdrawn; temperature 38.5°. Is stiffened, and every three or
four minutes, enormous tonic convulsion, with very violent opis-
thotonos, suspension of respiration, the heart continuing to beat, al-
though more slowly. The eye lacks sensitivity. The excitability is
much less evident than in strychnine poisoning. There are 4 or 5 of
these frightful convulsions during which it seems as if the animal is
going to fall from the table.
At 6:10, I administer to the dog a mixture of chloroform and
ether; at the beginning, it seems as if the convulsions grow worse.
But at the end of 2 or 3 minutes they disappear, and there are only
quiverings of the front legs, like those caused by phenol, which dis-
appear in their turn, as does the stiffening; the animal becomes re-
laxed and calm.
6:15, the anesthetic withdrawn. Sensitivity returns, then some
fits of stiffening; but there are no more great convulsions. Tempera-
ture 39°.
6:22; drew 33 cc. of blood, medium red D
6:45; the temperature is 38.5°.
7 o'clock; drew 33 cc. of blood, very dark E
The next day, the animal is quite recovered.
Blood A (air) . . contains, in 100 cc. . . 02 16.9; CO, 33.1
Blood B (oxygen, 1% atm.) contains, in 100 cc. 02 21.4; CO, 36.6
Blood C (oxygen, 7 atm.) . . contains, in 100 cc. 02 32.5; CO,
73.8; N 4.1
724 Experiments
Blood D (air, 27 min. after decompression) . contains, in 100 cc.
02 16.9; C02 21.0
Blood E (air, 67 min. after decompression) . contains, in 100 cc.
O, 17.0; CO, 31.5
The bag contained after the experiment a mixture of CO2 10.7
and 02 70 per cent.
Therefore the oxygen pressure when blood B was drawn was
about 1.75 x 79 = 138, and when blood C was drawn, about 7 x 71
= 497.
Experiment CCLXXXII. December 3. Dog.
Tube in the trachea; rectal temperature 38°; respirations extraor-
dinarily rapid.
3:20; blood drawn from the left carotid, 33 cc A
The oxygen bag is attached to the cannula in the trachea; a flask
at the bottom of which there are a few bits of potash is placed where
the air will pass over it.
3:30; drew 33 cc. of blood considerably redder; respiration has
become much slower B
3:45; placed in the large compression apparatus.
4 o'clock; pressure is 3% atmospheres; drew 33 cc. of very red
blood; no gas C
A series of petty accidents occur; at 4:40, I wish to decompress
suddenly; but the rubber bag gets in front of the opening, and the
decompression is not finished until 5:45.
The animal has neither convulsions nor quiverings; its tempera-
ture is 36°.
Blood A (air, normal pressure) . . contains . . . 02 18.1; CO, 24.9
Blood B (oxygen, normal pressure) contains . . . O2 20.9; CO, 33.7
Blood C (oxygen, 3V2 atmospheres) contains . . . 02 27.5; C02 56.5
The air of the bag contained before the experiment 85 per cent of
oxygen; when blood C was drawn, the tension was about 80 x 3.5
= 280.
Experiment CCLXXXIII. December 10. Vigorous dog, weighing
12.5 kilos.
At 3:45, tube placed in the trachea; the respiration becomes
panting.
3:55; drew 33 cc. of blood; the temperature is 38.5° A
4:10; forced to breathe from the rubber bag containing oxygen.
4: 18; drew 33 cc. of blood, redder B
4:35; placed in the large apparatus with the rubber bag, in which
a potash wash has been placed.
5:05; the pressure is 6 atmospheres; drew 38 cc. of blood. . . C
5:35; the pressure is 9 atmospheres; drew 35 cc. of blood. . . D
Some very small bubbles of gas appear.
5:38; decompression in 3 or 4 minutes.
When the animal is taken out, it is dead. The right auricle is still
beating. The venous blood is quite red, and when it is caught in a
glass, small bubbles of gas escape which come to the surface or re-
main clinging to the walls of the glass. Same phenomenon for the
Compressed Air; 02 Poisoning 725
arterial blood, only the bubbles are much smaller. The muscles and
the motor nerves respond to electricity.
When I drew blood D, the blood came with great difficulty into
the syringe in slow spurts. Probably the animal was dying at that
very moment; he had been observed to breathe up to that time; after-
wards, not.
At 7 o'clock, no rigor mortis.
Blood A (air, normal pressure) O. 19.8; C02 20.9; N 2.1
Blood B (oxygen at 88%, normal pressure) . O. 20.9; CO, 34.5; N 1.5
Blood C (oxygen, 6 atmospheres) 02 26.3; C02 63.5; N 3.9
Blood D (oxygen, 9 atmospheres) 02 30.7; CO, 61.5; N 5.5
The air of the bag, before the experiment, contained 88 per cent
of oxygen. So, taking account of the respiratory alteration, the oxygen
tension, when blood C was drawn, could be expressed by 80 x 6
= 480, and when blood D was drawn, by 78 x 9 = 702.
Experiment CCLXXXIV. December 17. Young dog, weighing.
7.5 kilos.
3:30; rectal temperature 39°.
Tube placed in the trachea; respirations very rapid.
3:40; drew 33 cc. of blood from the carotid, not very red. ... A
3:42; forced to breathe from the oxygen bag, with a potash wash
in the bag.
3:50; rectal temperature, 38.8°; drew 33 cc. of very red blood. B
Placed in the compression apparatus at 4:05.
4:50; 7 atmospheres; we try in vain to extract blood.
Taken to 7 and % atmospheres, and decompressed suddenly.
Withdrawn; temperature 37°. A few stiff enings and clonic con-
vulsions. The heart beats slowly, the blood is very dark.
Dies at 5: 10, without a last sigh, with complete resolution.
No urine in the bladder. But the kidneys, crushed with sulfate
of soda and animal charcoal, give a yellow precipitate with very
good Bareswill's reagent. The blood, treated in the same way, gives
a similar enormous precipitate; the potash browns the boiling liquid.
Blood A (air, normal pressure) contains O* 12.1; C02 29.6
Blood B (oxygen at 91%, normal pressure) contains 02 14.1; CO, 24.5
The oxygen tension was about 7.75 x 80 = 620.
Experiment CCLXXXV. December 20. Very vigorous dog, weigh-
ing 16.5 kilos. Rectal temperature 38.5°.
3:55; drew 33 cc. of rather dark blood. Respirations a little
slow A
4 o'clock; tube in the trachea; very much exaggerated respira-
tions for 4 to 5 minutes; then, period of calm, followed by other ex-
aggerated respirations. At 4: 10, while I am preparing to draw blood,
the respirations grow calm and return to normal type. At 4:12, drew
33 cc. of blood, less dark B
4:30; placed in the compression apparatus, with rubber bag.
5:05; pressure is 6 and % atmospheres; drew 40 cc. of very red
blood, from which very small bubbles of gas escape C
5:12; decompressed suddenly.
726 Experiments
When placed upon the table, has abundant froth in the mouth;
is in very violent opisthotonos, replaced from time to time by a
pleurosthotonos on the right side; at times strong clonic convulsions,
with a few intervals of complete repose. During the attacks, respira-
tion stops, and it is very difficult to detect the heart beats. The eye
remains sensitive.
At 5:15, the temperature is 36.7°, and the pulse only 20.
At 5:30; respiratory rate 48, pulse 112.
At 5:38, a little while after a strong convulsion, I draw 33 cc.
of very red blood D
At 5:45, temperature 35°.
I had the dog inhale chloroform through the trachea; respiration
is very active; the feet are then stiffened. Soon the respiration stops
in its turn; the eyes are very much swollen.
I use artificial respiration; the heart resumes strongly enough,
and respiration returns; then everything stops in spite of artificial
respiration, and the animal dies about 6 o'clock.
The serum of the blood, treated by sulfate of soda and animal
charcoal, gives with copper reagent a very abundant yellowish-red
precipitate.
Blood A (air, normal pressure, normal respiration) 02 15.1; CO, 40.8
Blood B (air, normal pressure, tracheal respiration) O, 20.3; CO; 24.0
Blood C (oxygen, 6% atmospheres) 02 34.6; C02 92.5; N 3.6
Blood D (during convulsions) O, 19.0; C02 14.8
The composition of the air of the bag, before the experiment, be-
ing 80% of oxygen, the tension at the time of drawing blood was
about 6.75 x 84 = 567.
Experiment CCLXXXVI. January 22. Temperature 16°. Large
dog.
At 3:10, tube placed in the trachea; rectal temperature 39.5°.
At 3:30, the animal breathing slowly and deeply, 33 cc. of carotid
blood drawn A
At 3:40, dog is placed in the compression cylinder, with the
rubber bag containing air with 88.6% oxygen.
At 4 o'clock, pressure is 4 atmospheres; then 33 cc. of very red
blood drawn B
At 4:15, pressure is 6V2 atmospheres. Drew 38 cc. of very red
blood, which coagulates very rapidly C
At 4:17, decompressed in 2 minutes.
Taken out in strong convulsions. They consist of attacks of stiff-
ness of the paws and of the body in opisthotonos, so strong that the
dog can be carried by one paw, like a piece of wood. (See Fig. 61.)
They can be brought on at will.
Rectal temperature 37°.
At 4:40, drew 33 cc. of moderately red blood; the temperature
has dropped to 36° D
The convulsions continue to decrease; the cannula is removed.
At 5:35, the convulsions have stopped. I draw a little carotid blood,
which, boiled with charcoal and sulfate of soda, gives a very strong
Compressed Air; O, Poisoning 727
reduction of the copper reagent. Nothing by sulfate of lime or
nitric acid.
The animal is placed in a cage fitted to collect the urine.
This urine, the next day, reduces copper reagent, giving an
abundant yellow precipitate.
Blood A (air, normal pressure) . . . . O, 15.8; CO, 43.0
Blood B (oxygen; 4 atmospheres) O, 23.9; CO, 59.0
Blood C (oxygen; 6V2 atmospheres) O, 28.7; CO, 69.4
Blood D (air; returned to normal pressure, convulsions) 02 12.4; CO,9.9
The bag contained at the beginning air with 88.6% of oxygen.
At the moment when blood B was drawn, the oxygen tension was
about equivalent to 320, representing 16 atmospheres. For blood C,
the figures would be 480 and 24 atmospheres.
Experiment CCLXXXVII. January 23. Temperature 16°. Large
dog.
Rectal temperature 39°. Tube placed in the trachea at 3:15. Its
respiratory rhythm does not change noticeably; it was very rapid.
At 3:53, its temperature dropped to 38.5°. 33 cc. of moderately
red blood drawn from the carotid A
At 4:02, placed in the apparatus with the bag containing super-
oxygenated air.
At 4: 15, pressure is 2 and % atmospheres.
I drew 45 cc. of very red blood, containing no free gases, with
a manifest tendency to coagulation. An accident prevents me from
analyzing it for its gaseous content.
At 4:38, pressure is 7% atmospheres.
I again draw 45 cc. of very red blood, coagulating rapidly, in
which no free gases appeared B
At 4:40, decompression in 2 minutes.
Taken out in strong convulsions. Rectal temperature 37°.
The convulsions, at first rather moderate, with intervals of
flaccidity, continue to increase in strength. In the intervals of tonic
convulsions, the animal moves its feet as if it were walking. The
tonic convulsions are so strong that the animal can be lifted like a
piece of wood, by one foot. Its feet are stiff, its body in right
pleurosthotonos, with opisthotonos of the neck, its eyes open, pro-
truding; the pupils dilated; it is vomiting.
At 5 o'clock it dies. The heart continues to beat for some
minutes.
At 5:10, drew 33 cc. of very dark blood with a catheter from the
left heart, which is no longer beating C
There is no urine in the bladder; very severe pulmonary con-
gestion.
Blood A (air, normal pressure) O, 17.2; CO, 22.3
Blood B (oxygen, 7Va atmospheres) 02 30.1; CO, 72.3
Blood C (after death) O, 1.4; CO, 29.0
The air of the rubber bag, analyzed after the animal had been
taken from the apparatus, contained O, 74%; CO, 10%.
At the moment when blood B was drawn, the oxygen tension
was about 540, equivalent to 27 atmospheres.
728 Experiments
Experiment CCLXXXVIII. January 24, temperature 17°. Vigor-
ous bulldog.
Rectal temperature 38.5°.
At 2:30, 33 cc. of carotid blood drawn; the animal breathes
quietly, by natural channels A
Tube placed in the trachea; respiration becomes much more
rapid.
At 2:45, 33 cc. of blood drawn B
At 3:25, the animal is placed in the apparatus, with the bag
containing superoxygenated air.
At 3:45, pressure 4 atmospheres, 41 cc. of blood drawn C
At 4:03, pressure has risen to 6 and % atmospheres; 57 cc. of
blood drawn D
At 4:07, decompression in 3 minutes. Rectal temperature 37°;
the animal is in strong convulsions.
At 4:33, the rectal temperature has fallen to 36°.
At 4:35, I administer chloroform; the first application causes con-
vulsions, which soon cease, and the animal becomes insensible and
in resolution. I stop administering chloroform at 4:45. Up to 5:55,
there are no more convulsions. Then they reappear.
The animal survives.
Blood A (air, normal pressure, respiration by natural channels)
02 16.0; C02 41.5
Blood B (air, normal pressure, tracheal respiration) 02 23.4; CO. 15.2
Blood C (oxygen, pressure 4 atmospheres) . . . 02 28.5; CO, 68.3
Blood D (oxygen, pressure 6% atmospheres) . . . 02 30.7; C02 82.0
Since the bag from which the animal had breathed contained
after the experiment 74.5% of oxygen and 8.6% of carbonic acid, we
can reckon at 300 the oxygen tension at the moment when blood C
was drawn, that is, 15 atmospheres of air, and at 510 at the moment
when blood D was drawn, that is, 25 to 26 atmospheres.
Experiment CCLXXXIX. January 28. Large dog, fasting since
the morning of January 27.
At 2:35, I draw 33 cc. of carotid blood, moderately red. ... A
I mix a few cubic centimeters of it with distilled water, to ex-
amine it for sugar (a). The rectal temperature is 38°.
The trachea is not opened, but the muzzle, pictured in Figure 37,
is fitted to the animal, and at 3:15 the dog is placed in the apparatus
with the oxygen bag.
At 3:50, the pressure is 6% atmospheres. Decompression is made
in 5 minutes.
The animal is in strong convulsions; tonic stiff enings, clonic con-
vulsions. Attacks provoked at will.
At 4 o'clock, I draw during the convulsions 23 cc. of dark carotid
blood B
Rectal temperature is only 36.5°.
At 4:25, drew 33 cc. of moderately red blood; the animal has
just had an attack C
At 4:50, the temperature is only 36".
Compressed Air; 02 Poisoning 729
At 5:10, another 33 cc. of blood, which is redder; the convulsions
had ceased a few minutes before D
At 6 o'clock, the animal is no longer in convulsions; when com-
pletely unfastened and placed on the floor, it walks like a hyena,
hind quarters very low. It is set aside for the collection of the urine.
It does not urinate until the next day at 3 o'clock; no sugar. At
that time, its temperature has risen to 39.5°.
Blood a, boiled with charcoal, does not reduce Fehling's solution.
On the contrary, a mixture of bloods B, C, D, boiled in a similar
way, gives a very considerable reduction. A part of the colorless
liquid obtained by boiling this blood with the addition of water and
much charcoal, being placed on the drying-stove, with brewer's yeast,
in a tube inverted over mercury, ferments and gives off a gas which
is absorbed by potash. Another part, cooled with copper reagent, dis-
colors it and precipitates.
Blood A (air, normal pressure) contained 02 16.0; C02 44.5
Blood B (in open air, convulsions) .... contained 02 9.7; C02 48.2
Blood C (after 25 min. in the open air) contained 02 13.9; CO, 10.5
Blood D (after 1 h. 10 min. in the open air) contained 02 18.5; C02 19.0
The air of the bag after the experiment contained 61.5% of
oxygen and 12.9% of carbonic acid. The oxygen tension had risen to
nearly 420, that is, 21 atmospheres of air.
Experiment CCXC. February 4. Large dog, which had not eaten
since the day before in the morning. Rectal temperature 37.5°.
At 3:15, 33 cc. of rather red blood drawn from the carotid. . . A
A small quantity of this blood is boiled with water, sulfate of
soda, and charcoal.
The animal, furnished with the muzzle and the oxygen bag, is
placed in the apparatus at 4 o'clock.
At 4:40, I make the decompression in a few minutes; the pressure
had reached 7 Vz atmospheres.
The animal is in excitable convulsions; its temperature is only 36°.
At 5:20, drew 33 cc. of very red blood B
The animal had just had convulsions, and in the interval breathed
very rapidly.
At 5:40, drew another 33 cc. of blood C
The convulsions are over at the time; the animal, when unfastened,
cannot walk.
It survives; the urine which it voids during the night contains no
sugar; the very abundant saliva found in the muzzle did not con-
tain any either. On the other hand, blood B was certainly richer in
sugar than blood A.
Blood A (before the experiment) contained 02 18.7; C02 44.0
Blood B (afterwards, during the convuls.) contained 02 23.2; C02 19.4
Blood C (convulsions over) contained 02 20.3; CO. 22.0
The air of the bag, after the experiment, contained 57.6% of
oxygen and 7.4% of carbonic acid.
The oxygen tension had therefore risen to about 440, that is,
22 atmospheres.
730 Experiments
Experiment CCXCI. February 5. Terrier, medium size, fasting
since the preceding evening.
Rectal temperature 39.5°.
At 5 o'clock, put into the apparatus with the muzzle and the
oxygen bag.
At 5:40, pressure is 7 and Vz atmospheres.
From 5:40 to 5:45, decompression.
Is in strong convulsions, with violent snapping of the teeth.
Temperature 38°.
Dies at 6 o'clock.
The air of the bag, after the experiment, contained 77.2% of
oxygen and 8% of carbonic acid.
The oxygen tension had been about 560, corresponding to 28
atmospheres of air.
Experiment CCXCII. February 7. Vigorous poodle.
Temperature 39.8°.
Took blood from the carotid to analyze for sugar a
At 4 o'clock, muzzle and oxygen bag; the compression begins.
At 4:43, the pressure is 7% atmospheres; rapid decompression.
Taken out of the apparatus, the dog has 2 or 3 convulsions; its tem-
perature is 38°; it dies while we are drawing a little very dark arterial
blood, which is treated with sulfate of soda b
a and b are treated in the same way, with the same addition of
water and according to the method of CI. Bernard. Now 5 cc. of
the filtered liquid furnished by a reduce only 10 drops of copper
reagent, while the same volume of the liquid in b reduces 15.
The air of the bag before the experiment contained 90% of
oxygen. After the experiment, there was only 76.5% with 10.7% of
carbonic acid.
The oxygen tension had therefore risen to about 600, which cor-
responds to 30 atmospheres of air.
Experiment CCXCIII. February 18. Dog weighing 10 kilos, fast-
ing since the morning of February 17. Rectal temperature 40°.
At 1:30, I put a tube in its trachea.
At 2 o'clock, its rectal temperature is only 39.8°.
From 2:05 to 2:20 (15 minutes), I force it to inspire and expire
in a rubber bag containing 41 liters of air; towards the end, the ani-
mal experiences a certain respiratory difficulty, takes great inspira-
tions, and struggles a little. I call the air of this bag a.
At 2:45, I take 25 gm. of blood from the carotid and mix it with
25 gm. of sulfate of soda and 10 gm. of distilled water . . . . x
At 2:55, put into the compression apparatus, with the oxygen
bag, in which is a little alkalinized water.
At 3:16, pressure is 5% atmospheres; decompression in 2V2 min-
utes. The dog displays only slight convulsions, lasting hardly quarter
of an hour. He has salivated very abundantly; his temperature is 38°.
At 3:25, drew 25 gm. of carotid blood which is treated like
blood x y
At 3:40, drew 33 cc. of blood; the animal' has been breathing
quietly for some time A
Compressed Air; O. Poisoning 731
From 3:43 to 3:58 (15 minutes), I make the dog breathe in a bag
containing the same quantity of air as bag a; I call this air b. The
animal suffers also at the end of this respiratory period.
At 4:20, the animal being very quiet, I draw 33 cc. of carotid
blood B
At 4:45, rectal temperature 36.5°.
At 6 o'clock, drew 33 cc. of blood C
Immediately after, his temperature is 37°.
At 6:15, I draw more blood which I treat like x and y z
Rectal temperature 37°.
I remove the tracheal cannula; the dog can walk a little. At
7: 10, his temperature has risen to 39°. He survives.
Since the air of the bag contained before the experiment 90.8%
of oxygen, and after the experiment, 77.3% of oxygen and 8.4% of
carbonic acid, the tension rose to 440, that is, 22 atmospheres of air.
Blood A (22 min. after the decompression) contained 02 17.5; C02 20.0
Blood B (1 hour after the decompression) contained O, 17.2; C02 17.0
Blood C (2 hours 40 minutes after the decompression) contained
O, 16.3; CO, 26.5
The liquids produced by boiling bloods x, y and z give the follow-
ing results:
5 cc. of the liquid furnished by x (before the compression) dis-
color 15 drops of copper reagent.
5 cc. of the liquid furnished by y (10 minutes after the decom-
pression) discolor 35 drops of copper reagent.
5 cc. of liquid furnished by z (3 hours after the decompression)
discolor 15 drops of copper reagent.
The analyses of airs a and b show that:
1. In a, before oxygenated compression, the dog consumed in 15
minutes 4.89 liters of oxygen, and produced 2.99 liters of CO.; that
is, in one hour 15.56 liters of oxygen and 9.98 liters of CO2.
2. In b, after the compression, the dog consumed in 25 minutes only
3.37 liters of oxygen, and produced only 1.88 liters of CO?; that is,
in one hour 8.88 liters of oxygen and 4.51 liters of CO,.
Experiment CCXCIV. February 23. Strong female spaniel.
Rectal temperature 39°.
At 2:15, I put a tube into the trachea; the respirations become
•very rapid, 110; pulse 120.
At 2:40, took from the carotid 25 gm. of blood, which is treated
as usual in the test for sugar x
At 2:40, the rectal temperature is 38°. The respiration grows
calm, and falls to 40 per minute.
From 2:45 to 3 o'clock (15 minutes), the animal breathes in a
closed bag, containing 47.14 liters of air. The breathing, calm at first,
becomes difficult at the end of 7 or 8 minutes. I call the air of this
bag a
At 2:45, the rectal temperature is still 38°.
At 3:15, put into the apparatus with the oxygen bag.
At 3:40, pressure is 6 and % atmospheres; decompressed sud-
732 Experiments
denly. Is in quite strong convulsions. White foam very abundant in
the mouth.
Rectal temperature 37°.
At 3:45, drew a little blood for sugar analysis; the animal is in
convulsions y
At 4 o'clock, the animal is calm; respiratory rate 14, pulse 60.
From 4:12 to 4:27 (15 minutes), made to breathe in the same
quantity of pure air as above b
The respirations remain calm the whole time.
At 5 o'clock, rectal temperature still 37°. The animal, when put
on the floor, walks quite well. It survives.
The air of the oxygen bag contained at the beginning of the ex-
periment 86.4% of oxygen; at the end, it contained only 68.1% with
10.4% of carbonic acid. The oxygen tension then must have risen
to about 460, or 23 atmospheres.
The liquid furnished by blood x discolors per 5 cc. between 10
and 15 drops of copper reagent; that of blood y discolors between
15 and 20.
As to the consumption of oxygen, it was in experiment a 3.95
liters, and in experiment b it fell to 2.15 liters. The production of
carbonic acid also dropped from 2.41 liters to 1.99 liters.
Experiment CCXCV. February 24. Female dog weighing 17 kilos.
2:55; respiration by natural channels, calm; vaginal temperature
40°. I draw 33 cc. of carotid blood A
3:12; I place a tube in the trachea; rapid respirations; then 1
take 500 gm. of arterial blood.
3:47; took 25 cc. of blood (temperature 39°) B
From 4:10 to 4:40, placed in the apparatus with a bag contain-
ing air with 93% oxygen. Pressure rises to 6 and % atmospheres.
Decompressed suddenly, found dead, limp, temperature 37°.
The oxygen tension had risen to about 580, that is, 29 atmos-
pheres of air.
Blood A (natural respiration) Oz 17.0; CO> 38.5
Blood B (tracheal respiration, copious bleeding) O, 16.5; C02 14.4
Experiment CCXCV I. February 25. Dog weighing 15 kilos.
While he is breathing by the natural channels, I draw 33 cc. of
carotid blood A
Rectal temperature is 40°.
I then place a tube in the trachea, and extract in one hour 400 cc.
of arterial blood. He does not make any extraordinary or rapid
respirations, but his temperature drops to 37.5°; I take the last 33 cc.
of blood for analysis B
From 3:45 to 4:40, raised to the pressure of 6V2 atmospheres,
with a bag containing air with 90% of oxygen.
Taken out in strong convulsions, excitable by the introduction
of the thermometer into the rectum. Temperature 36°.
The convulsions continue, and the animal dies during the night.
The maximum oxygen tension was about 520, corresponding to
26 atmospheres of air.
Compressed Air; O, Poisoning 733
Blood A (natural respiration) 02 19.0; C02 42.0
Blood B (tracheal respiration, copious bleeding) . . 02 13.1; C02 13.2
Experiment CCXCVII. May 24, 1874. Experiment made before the
committee of the Academy of Sciences.
Female dog of moderate size. Tube in the trachea. Oxygen bag.
Compression taken to 7 atmospheres. At that time (5:30), I draw
35 cc. of carotid blood, from which some free gases escape. This
blood contains 33.2 cc. of oxygen per 100 cc. of blood, 76 of carbonic
acid, and 6.6 of nitrogen.
Sudden decompression at 5:35; the animal has no convulsions.
A quarter of an hour afterwards, they occur in fits, and can be pro-
duced; at certain moments, the dog becomes as stiff as wood.
She is chloroformed; the convulsions cease, but reappear when
consciousness returns. At 6:30, lying on her side, constantly makes
the movements of walking with her two front feet.
At 7:30, rigidity again.
The next day, at noon, this rigidity persists. The animal has re-
mained all night lying on the ground, without having moved from
the spot. The eye lacks sensitivity, the pupil does not react to light;
the rectal temperature is 23°, that of the room being 19°.
The dog dies during the day.
I hope that the reader will not object to this long series of
descriptions. The symptoms which I am studying at present
seemed to me so important that it was necessary to give many
examples in detail. The questions which present themselves are
numerous. We are now well enough informed to settle almost all
of them.
But first, according to our custom, we should draw up a table
(Table XV) which summarizes the principal results of the data
which we have just reported. I listed the experiments according
to the increasing oxygen tension, expressed in Column 4 by its
real value, and in Column 5 by the equivalent in atmospheres.
We are now ready to make a complete description of the fatal
effects of oxygen, to describe its symptoms, and even to analyze
the mechanism of the poisoning.
Let us first discuss the concentrations.
The convulsive symptoms, as Columns 5 and 10 of the table
show us, did not appear clearly until about 19 atmospheres. Dogs,
then, seem a little less sensitive than birds, upon comparing this
result with that in Table XIV. That would not be surprising,
but I do not hesitate to say that on this point my experiments do
not furnish sufficiently definite information.
I can only say that the duration of the compression has much
to do with the intensity of the symptoms of oxygen poisoning.
734
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Compressed Air; 02 Poisoning 737
I have sometimes seen them occur at pressures hardly over 10
atmospheres of air, and even result in death. Here, for example,
are three experiments.
Experiment CCXCVUI. April 26. A rabbit and two sparrows are
placed in the large compressed air receiver.
From 1:45 to 2:45, the pressure is raised to 10 atmospheres.
About 5 o'clock, on looking through the windows of the apparatus,
we see the animals are dead.
Experiment CCXCIX. April 30. Dog weighing 4.300 kilos. At
9:45, placed, free, in the large receiver.
The pressure is raised to 10 atmospheres at 10:30; then the little
exhaust cock is opened, so that a current of air under 10 atmospheres
is maintained; the pressure even rises to 11 atmospheres at 10:45; at
that time we look in through the portholes and see the dog lying on
its back, in a kind of convulsion. The pressure is lowered to 10,
and almost immediately the animal recovers, stands up on his feet,
and barks wildly.
At noon, the pressure is still 10 atmospheres; the dog has remained
standing and begins to bark furiously when anyone approaches the
apparatus.
The current of air under pressure is maintained.
At 2: 15, the animal is lying down, struggling half convulsively.
It dies at 5 o'clock; as the cock has been closed for some time, a
sample of air is taken which appears practically pure (O. 19.8; C02
0.4).
Experiment CCC. February 15. Two mountain sparrows are kept,
from 11:30 to 5:30, under a pressure of air varying from 8x/2 to 9V2
atmospheres; constant current of air.
One of them (A), at the end of a stay of several hours, gives
increasing signs of discomfort.
Very slow decompression. A is much weakened, has convulsive
movements of the wings, feet, and tail; its temperature, which was 41°
at the beginning, is only 33.8°. At 7 o'clock in the evening, it still
has convulsive movements, leans backward on its tail.
The other sparrow seems quite well. Its temperature is 39°.
Both die during the night.
I do not dwell on these last experiments. To return to those
summarized in Table XV, we see that though for compressions
of short duration convulsions begin to appear with an oxygen
tension a little lower than the value of 19 atmospheres of air,
they are strong and constant above 20 atmospheres, and always
entail a very rapid death when above 27 atmospheres. In the only
experiment (Experiment CCLXXXIII) in which the oxygen ten-
sion rose to the value of 35 atmospheres, the animal was already
dead when taken from the apparatus.
Let us consider now the oxygen content of the arterial blood,
738 Experiments
as shown in Column 7 of the table. We find rather large differences
there. Whereas, for example, in Experiment CCLXXXI, in which
the oxygen proportion rose from 14.9 to 32.5, although seized by
violent convulsions, the animal survived, the dog in Experiment
CCLXXXVII died in 20 minutes, without having in its blood more
than 30.1% of oxygen, the initial proportion being 17.2. All the
results show that it would be impossible to fix exactly either the
absolute quantity of oxygen with which convulsions and death
occur or its proportional increase. Yet whenever the animal died,
the quantity of oxygen always exceeded 30 volumes per 100 vol-
umes of blood.
The average increase is, we see, very slight, since it oscillates
between a third or a half above what exists normally.
If, in order to examine their general course with more profit,
we express by graphs, in our usual manner, the results contained
in Column 7, we get Figure 60. The many variations which we
noted are shown here very clearly.
But if we slide all these lines up vertically, making the origin
of each the number 20, and if we take the average of the different
points corresponding to about the same pressure, we get definitely
a line of remarkable regularity, that is, a straight line.
So, in the living animal, we find confirmed the experiments in
vitro included in Subchapter V of Chapter II: from one atmosphere
on, there is added to the biood only dissolved oxygen.
It is a fact worth noting that convulsions may appear when the
blood has an oxygen content appearing sometimes in healthy ani-
mals, which they may almost reach after rapid respiration. We see
first then that it is not the proportion oi oxygen contained in the
blood which is of itself dangerous; we see next that the increase
of this proportion, even to a high degree, does not constitute the
danger. This increase must be permanent, must be the result, not
of a better saturation of the corpuscles as an effect of more com-
plete aeration, a saturation which the reducing action of the
tissues soon restores to the normal degree, but of a saturation due
to the fact that the tissues themselves are saturated with oxygen
and in equilibrium with the blood.
That is why the convulsions occur only after the compression
has lasted some time. The tissues must be impregnated with
oxygen in addition to what the blood, loaded with it in the lungs,
brings them and incessantly gives over to them.
At the beginning of these experiments I asked myself whether
the blood was not directly altered by the excess of oxygen, and did
Compressed Air; O, Poisoning
739
not thus become the cause of the convulsive symptoms. Inspection
of the corpuscles through the microscope, it is true, showed me no
alteration of forms and dimensions; but that did not satisfy me. I
Fig. 60 — Dogs poisoned by oxygen: increasing oxygen content of their
arterial blood.
740 Experiments
resolved then to inject into a healthy dog blood which had been
greatly superoxygenated. I did so in the following experiments.
Experiment CCCI. June 30. Defibrinated dog blood, shaken in
the apparatus pictured in Figure 45, under a pressure of 10 atmos-
pheres of air with 65% of oxygen. Next the excess of gas was expelled
by whirling the flask containing the blood at the end of a cord, like
a sling. It then contained 24 volumes of oxygen per 100 volumes of
blood. I injected 200 cc. of it into the femoral vein of a female dog
weighing 6 kilos.
No symptom, not even apparent discomfort.
Experiment CCCII. July 23. Defibrinated dog blood; treated like
the preceding at 10 superoxygenated atmospheres; it contained 34
volumes of oxygen.
I bled a little dog weighing 1640 gm. from the carotid; I took
from him 20 cc. of very red blood (this blood clotted with extraor-
dinary rapidity), containing only 7.3% of oxygen, with 33% of car-
bonic acid; the arterial pressure was 13 cm.
I injected into his jugular vein 35 cc. of the blood supersaturated
with oxygen, which had been whirled like a sling.
No effect.
Experiment CCC1II. August 10. Defibrinated dog blood, treated
as above, at 10 superoxygenated atmospheres; contained 33 volumes
of oxygen.
Little dog weighing 2085 gm.; rectal temperature 36°; pulse 160;
respiratory rate 50. I took 100 cc. of blood from him; he became very
weak; his temperature fell to 34.5°; pulse 128; respiratory rate 30.
I then injected into his jugular 110 cc. of superoxygenated blood;
immediately the animal revives, and when put down on the floor,
seems only a little weak.
No after-effect.
And so in conditions of compression, that is, oxygen saturation,
similar to and even greater than those which caused death, the
blood acquired no dangerous quality, and can be substituted safely,
in a very great proportion (1/19 of the weight of the body) for
the blood of another animal. I must add that the agitation in
compressed oxygen had lasted only a very short time, less than
one hour. We shall see in Subchapter III of Chapter VI other
experiments made from another point of view with blood shaken
for several hours with compressed oxygen.
But let us come to the description of the convulsive attack itself.
It is truly curious and terrifying.
Let us take a case of average intensity. When the animal is
taken from the apparatus, it is generally in severe tonic con-
vulsions; the four feet are stiff, the trunk is bent back or a little to
Compressed Air; O., Poisoning
741
one side, the eyes protrude, the pupils are dilated, the jaws are
clenched. Ophthalmoscopic examination shows copious hemor-
rhage at the back of the eye. Soon there occurs a sort of relaxing
to which succeeds a new fit of stiffness with clonic convulsions re-
sembling both a strychnine crisis and an attack of tetanus. These
fits during the intervals of which the dog does not relax completely,
but remains in opisthotonos, breathing with great difficulty, check
the respiration, the heart still continuing to beat, although often
with surprising slowness; the arterial pressure drops considerably.
Sensitivity remains and one can excite new convulsions by it. After
some time, these convulsive periods, which at first appear every
five or six minutes, become rarer, then less violent; the stiffness
'J.iSjifip^uh
Fig. 61 — Dog during the tonic convulsions of oxygen poisoning.
742 Experiments
lessens in the intervals, and finally all symptoms disappear at the
end of a few minutes or, at the most, a few hours.
In lighter cases, instead of attacks so violent that one can lift
the animal by a single foot, stiff as a piece of wood, as Figure 61
shows, we observe irregular movements, local convulsions, symp-
toms, in a word, which are much like those of poisoning by phenol.
We sometimes see acts which seem to indicate a certain mental dis-
turbance.
In very serious cases, on the contrary, the stiffness is continual,
with a few clonic increases from time to time; the teeth grind
and clench so as to appear nearly ready to break, and death may
occur after one or two attacks, separated by a few minutes. We
then find the blood red, even in the portal system; then it turns
dark. When the animal no longer makes any movement, the heart
still continues to beat for a few minutes. At other times, as in
Experiments CCLXXVIII and CCXCVII, the convulsions last
nearly 24 hours before ending in death.
We find no congestions or ecchymoses in the lungs and the
nervous centers. Only consistently in sparrows, we see the cranial
diploe filled with a hemorrhage in dots, in smaller or larger spots,
or even in a sheet covering the occipital region, and, in the most
violent cases, the whole extent of the cranium. These bloody
suffusions, the cause of which does not seem to me easy to explain,
are invariably present in oxygen poisoning. They appear some
time before the moment of death. But they are not peculiar to
this kind of death, and in the preceding experiments we find them
noted, even in simple asphyxia, under diminution of pressure (See
Experiments CCLII and CCLIII).
The appearance of the symptoms which we have just described
seems to indicate that the toxic action produces its effect on the
nervous centers, as do strychnine, phenol, and other poisons which
cause convulsions. This conjecture is corroborated by the fact
that inhalations of chloroform stop the convulsions momentarily,
although they reappear when the anesthesia has worn off. Let us
remember that, according to our experiments on frogs, if the
sciatic nerve has been cut in the hind leg, there are no convulsions
in the muscles animated by this nerve.
To summarize all these facts, I shall quote here the con-
clusions of the report which I had the honor to make on this subject
to the Academy of Sciences, February 17, 1873.
Compressed Air; 02 Poisoning 743
1. Oxygen acts like a poison which is rapidly fatal, when its
quantity in the arterial blood rises to about 35 cubic centimeters per
100 cubic centimeters of liquid;
2. The poisoning is characterized by convulsions which, according
to the intensity of the symptoms, represent the different types of
tetanus, strychnine, phenol, epilepsy, etc.;
3. These symptoms, which are quieted by chloroform, are due to
an exaggeration of the excito-motor power of the spinal cord;
4. They are accompanied by a considerable and constant drop of
the body temperature.
It is this last point, purposely set aside until now, that I shall
discuss next.
2. The Diminution of Oxidations by Oxygen Poisoning.
When for the first time I saw a sparrow struggling in violent
convulsions under the influence of compressed oxygen, I imagined
at first that the intra-organic oxidations had been so overstimulated
in this bird that it was dying from burning itself out too quickly,
producing thus a quantity of exaggerated heat, which perhaps be-
came the direct cause of death. I thought therefore that the
thermometer would show me a rise in the bird's temperature.
Great was my surprise when I noted an absolutely opposite result.
In fact, in all the experiments, as the numbers listed in Column
5 of Table XIV and Column 9 of Table XV show, the temperature
of the experimental animals dropped considerably, before and
during the convulsions due to the oxygen.
At the beginning of the poisoning, when the convulsive symp-
toms were just commencing to appear, the temperature fell (Ex-
periments CCLXI, CCLXII, CCLXVII) . During the convulsions, it
falls more, and when the convulsions are to end in death, it reaches
very low figures (Experiments CCXCIII, CCLXXXI, CCLXXVIII,
CCXCVII), especially in birds, in which it goes below 30, and
sometimes even below 20 degrees (Experiment CXXXVII).
If, on the contrary, the animal is to survive, its temperature rises
and returns in a few hours to its normal value (Experiments
CCLX, CCLXII, CCLXVII, CCLXXXIX, CCXCIII) .
It is, therefore, a firmly established fact that the excess of oxy-
genation of the organism results in a diminution of intensity in the
chemical acts which produce the animal heat.
If the falling of the temperature of the body has given us a
certain though indirect demonstration of this strange fact, we
should find the direct proof when we examine either the absorp-
744 Experiments
tion of the oxygen or the two important excretions of urea and
carbonic acid.
Pulmonary exchange. Let us speak first of the consumption of
oxygen and the production of carbonic acid, which are measured by
the same experiment.
The experiments reported in Chapter I on birds which died in
confined and compressed air show that these two phenomena less-
ened in intensity during the compression. But it is not possible to
draw any conclusion, because the carbonic acid which is stored up
in the tissues of the animal adds its action to that of the oxygen,
and we shall see in Chapter VIII that carbonic acid also diminishes
the oxidations.
As to the experiments reported in the present chapter, they can-
not furnish any information as to what takes place during the com-
pression.
I therefore had to plan special experiments; unfortunately, the
problem presented more serious difficulties than one might have
supposed at first glance.
In dealing with animals kept in closed vessels, as the idea was
to turn out, for the reason which has just been stated it was neces-
sary to eliminate the carbonic acid and keep to the measurement of
the oxygen consumed. Now under the influence of pressure, there
must be dissolved, in the very body of the animal, a certain
quantity of oxygen which it is impossible to estimate and subtract
from the total quantity of oxygen that has disappeared.
That is not all. In the numerous experiments which I have tried
by this method, I took care always to act comparatively, to put
simultaneously two identical animals, one under a bell of known
capacity at normal pressure, the other in a compression receiver at
a determined pressure, with a potash solution which absorbed the
carbonic acid as it was formed. After a certain time had elapsed,
I analyzed the two airs, and I could easily determine the quantity
of oxygen absorbed by each of the two animals during a certain
unit of time. Unfortunately, the percentage analyses made neces-
sarily upon a small volume taken from the total mass of air in the
experiment have to be multiplied by this mass, to get the total con-
sumption, and the causes of error of either chemical or physiologi-
cal nature then assume a value so great that they exceeded the
differences noted between the two analyses.
I therefore had to give up this type of experiment completely.
I used two others, which are not subject to the same criticism.
The first is a little indirect. It consists of comparing the quantity
Compressed Air; O. Poisoning 745
of carbonic acid given off by the same animal placed successively
in a closed vessel, in ordinary air or in a superoxygenated air at the
same degree of compression. The special action of the carbonic acid
is thus eliminated, because it is obviously the same in both cases.
Here are the details of an experiment conducted in this way.
Experiment CCCIV. Albino rat. Rectal temperature 38°. May 10.
Placed from 4:05 to 6:35 (2 hours 30 minutes) in the large receiver
made of a mercury bottle (containing 3 liters), under a pressure of
3V4 atmospheres of air. When he is taken out, his temperature has
fallen to 30°; he is quite sick, breathes slowly and deeply, but recovers
quite quickly.
The air of the flask contains 12.5% of oxygen, and 6.6% of car-
bonic acid.
May 12. The animal has recovered perfectly; we begin again the
same experiment, as to pressure and length; but this time we use air
containing about 60% of oxygen. The tension of this gas corresponds
then to that of compressed air from 9 to 10 atmospheres.
At decompression, the animal is found very low, not sensitive to
pinching, but sensitive in the cornea. His rectal temperature is only
23.8°. He does not move, and dies at the end of a half-hour; no gas
in the blood vessels.
The air in the receiver contained only 5.3% of carbonic acid.
Experiment CCCV. July 1. A. Two sparrows weighing together
38 gm. are subjected to a pressure of 5 atmospheres of air for 32
minutes, in the Seltzer water receiver.
Taken out after sudden decompression, seem very well, with
slight bloody suffusions on the cranium.
During this time they consumed 3.9% of oxygen, and produced
2.8% of carbonic acid.
B. Two other sparrows, weighing together 39 gm., are placed next
in the same apparatus, at the same pressure, but in air containing
72.6% of oxygen; the tension, 5 x 72.6 = 363.0, corresponds to about
that of 18 atmospheres of air. They remain in the apparatus for 27
minutes.
At the end of 5 minutes there occurred in the two birds convul-
sions which lasted with intensity for 15 minutes. Then the sparrows
remain lying on their backs, panting heavily.
One of them dies at the end of an hour; the other, after seeming
to recover, but keeping up incessant muscular quiverings, is seized
with convulsions after an hour and a half, and dies in a half hour.
Both immediately take on rigor mortis; moderate bloody suffu-
sions.
In 27 minutes they consumed 2.05% of oxygen, 1.07 in the 'first
17 minutes and only 0.35 in the last 10; they produced in the first 17
minutes 1.07% of carbonic acid, and 0.28 in the rest of the time, in
all 1.35.
We see from these figures that in 10 minutes at 3 atmospheres of
air 1.2% of oxygen was consumed and 0.8% of carbonic acid was
746 Experiments
formed, while at a tension corresponding to 18 atmospheres of air
the consumption was only 0.7 and the production 0.5.
These experiments show very clearly that the absorption of
oxygen and the production of carbonic acid decrease when the
oxygen tension increases; the difference increases in proportion to
the length of the experiment. Experiment CCCVI shows that at 9
or 10 atmospheres of air this effect is produced clearly, and that at
this low pressure death may occur after an exposure that has been
prolonged enough.
The second experimental method I used consisted of collecting
and measuring all the carbonic acid produced by an animal during
a certain time under different pressures but in a current of air that
is always pure.
Experiment CCCVI. Rat weighing 160 gm.
July 28. Placed for a half hour in the Seltzer water apparatus,
at normal pressure, under a current of air providing 2 liters per min-
ute. The apparatus is immersed in water at 20°. The air which escapes
is collected in a bag, and then connected with the potash bubbler of
Figure 65, which absorbs all the carbonic acid from it; the carbonic
acid is then extracted by one stroke in the mercury pump.
The temperature of the animal dropped from 38° to 37.5°.
It produced 247 cc. of carbonic acid.
August 2. Same animal, same general arrangements.
Kept under a current of air but this time at a pressure of 9
atmospheres, during the same length of time.
On being taken from the apparatus, its temperature has dropped
from 38.1° to 34.6°.
Produced 176 cc. of carbonic acid.
In two of the experiments (CCXCIII and CCXCIV) made on
dogs, which were reported in the preceding subchapter, I measured
the oxygen consumption, and at the same time the production of
carbonic acid, not during the compression, but during the moments
following the decompression, and even in the midst of an attack of
convulsions.
This measurement was interesting only from the comparative
point of view. The method which I used, which makes no claim to
absolute accuracy, allows me to compare what a dog was capable of
absorbing and producing before being subjected to compressed air
with what he consumes and produces when he has been taken from
the cylinder.
The experimental animals had a tube in the trachea. I con-
nected this tube with a bag filled with a known volume of air and
let the animal breathe into the bag for a certain time. Since the
Compressed Air; 02 Poisoning 747
operation was repeated several minutes after the decompression,
two chemical analyses allowed me to determine the quantity of
the gases absorbed and given off in both cases.
Experiment CCXCIII shows that although before the compres-
sion the dog had consumed in a quarter of an hour 4.89 liters of
oxygen and produced 2.99 liters of CO., after he had been taken
from the apparatus in the same time he consumed only 2.02 liters
and formed only 1.12 liters. Similarly, in Experiment CCXCIV, the
consumption of oxygen fell from 3.95 liters to 2.15 liters, and the
production of carbonic acid from 2.41 liters to 1.99 liters.
The decrease in the production of carbonic acid through the
superoxygenation of the organism is indicated again by the study
of the numbers listed in Column 8 of Table XV. If we examine
Experiments CCLXXX, CCLXXXI, CCLXXXV, CCLXXXVI,
CCLXXXVII, CCLXXXIX, CCXC, CCXCIII, we see that some
minutes after the decompression we find in the blood only minimal
proportions of carbonic acid. And this fact is all the more remark-
able because, in the conditions in which the experiments were
made, carbonic acid had been stored up in the blood in consider-
able quantity during the compression. Now when the animal was
restored to the open air, this acid lessened to far below the normal
proportion; in Experiment CCLXXXIX, it fell to 10.5 volumes per
100 volumes of blood, although its regular proportion, before the
compression, was 44.5; in Experiment CCLXXXVI, the proportion
before the compression being 43.0, it became 69.4 during the com-
pression, and dropped to 9.9, 20 minutes after; in Experiment
CCLXXXV, the same figures were 40.8, then 92.5, and finally 14.8.
It is quite clear then that, in consequence of the exaggerated
superoxygenation of the organism, carbonic acid ceased to be pro-
duced in the tissues, and to pass into the blood, or at least that these
phenomena were considerably slackened. This would have been
manifest even during the compression, if I had been able to keep
the animals in a current of compressed oxygen, to avoid the storing
up of the carbonic acid due to the confinement. Furthermore, the
experiments reported in Chapter II, in which we were dealing with
pressures which were rather low but were made with almost pure
air, showed, as we have noted, a diminution of the carbonic acid of
the blood (See Table XII).
It appears from these data that the pulmonary ventilation would
be capable of removing from the blood much more considerable
proportions of carbonic acid than one would have thought, of al-
most exhausting, in a word, the bicarbonates and the phospho-car-
748 Experiments
bonates, if the organism did not unceasingly furnish the venous
blood with a constant source of this gas. We shall return to these
data in another chapter, but it would be interesting to see, by a
simple experiment, in which the same blood would be forced by a
pump to pass constantly through the lungs, in which artificial res-
piration would be maintained, how much carbonic acid this blood
could lose.
Before leaving this subject, let us say that the carbonic acid re-
appears but slowly in normal proportion in the arterial blood, when
the superoxygenated animal recovers and lives. In Experiment
CCLXXXIX, at the end of 1 hour and 15 minutes the proportion of
carbonic acid was only 19.0; in Experiment CCXCIII, after 2 hours
and 40 minutes, it had risen only to 26.5; but in Experiment
CCLXXXI, at the end of 67 minutes it had returned to its original
figure, 31.5. Let us note that this tendency to return to the normal
proportion does not always indicate that the animal will survive,
as Experiment CCLXXX shows.
Excretion of Urea. I now come to the urea. The experiments
were conducted like those in the case of diminished pressure. The
animal, subjected to a fixed diet for several days, was kept for
several hours in compressed air, with a suitable current of air. The
urine voided spontaneously or collected with a catheter in the pre-
ceding 24 hours was compared with that given in the 24 hours in
which the compression took place. The account of the experiments
will give the necessary details.
Experiment CCCVII. Dog weighing 12 kilos, eats every day at 7
o'clock in the morning a soup composed of 250 gm. of bread, 250 gm.
of meat, and 500 gm. of water.
July 25, at 8 o'clock in the morning, catheterized the animal,
which was then placed in a cage where the urine can be collected;
he does not urinate, and July 26, at 8 o'clock, another catheterization
gives 280 cc. of urine. This urine, analyzed by the Yvon process,
gives 4500 cc. of nitrogen, that is, 12.1 gm. of urea.
July 26, from 9 o'clock to 3 o'clock, is subjected to a pressure of
8 atmospheres, under a current of air. Decompressed from 3 o'clock
to 5 o'clock, is taken out in good condition. His rectal temperature
is 35.5°.
July 27, at 8 o'clock in the morning (rectal temperature 35.7°)
he is catheterized and the urine thus obtained is added to what he
voided spontaneously. The total is 350 cc. of urine, which gives only
1398 cc. of nitrogen corresponding to 3.7 gm. of urea. I must add that
the animal would eat only half his meal.
July 28, at 8 o'clock in the morning, catheterized again; there are
520 cc. of urine giving 3838 cc. of nitrogen, that is, 10.3 gm. of urea.
During this day, the animal had absolutely refused to eat.
Compressed Air; 0_, Poisoning 749
Experiment CCCVIII. Dog weighing 16 kilos; since July 31, eats
every day 250 gm. of bread, 250 gm. of meat.
August 3, at 8:30, catheterized.
August 4, at 8:30, catheterized, and this urine added (100 cc.) to
what was voided in the 24 hours (475 cc.) It gives, by the Yvon pro-
cedure, 8062 cc. of nitrogen, that is, 21.6 gm. of urea. Rectal temper-
ature 35.8°. At 9 o'clock in the morning, placed in the apparatus,
where the pressure rises to 8 atmospheres; decompression begun at
4:50, still under a current of air; the animal is removed from the
apparatus at 6:20; he is in good condition; his temperature is 35.5°.
August 5, at 8:30 in the morning, the catheter drew 245 cc. of
urine; there was none in the apparatus. It gave only 6329 cc. of
nitrogen, corresponding to 16.9 gm. of urea.
These examples are enough to show that the chemical
phenomena on which depend the formation of urea and analogous-
products are impeded in the same manner as those which determine
the production of carbonic acid.
Sugar of the Blood; Glycosuria. A search for sugar in the blood
and the urine shows us another chemical transformation, the de-
struction of this sugar, impeded by the action of oxygen under ten-
sion. In Experiment CCLXXXVI, the dog, which survived after
convulsions of extreme violence, voided after the decompression
urine with great sugar content; in Experiment CCLXXXI, which
ended in rapid death, the few drops of urine which the bladder
contained had high sugar content. This glycosuria, however, is not
constant (Experiment CCXC) .
Experiments CCLXXXV, CCLXXXVI, CCLXXXIX, CCXC,
CCXCII, CCXCIII, and CCXCIV, that is, all in which the blood
was tested for sugar, showed first that there is always much glucose
in the arterial blood of a dog which has been subjected to com-
pression. But as we always find glucose in arterial blood when it is
treated according to the method of M. CI. Bernard by boiling with
sulfate of soda, comparative experiments CCLXXXIX, CCXC,
CCXCII, CCXCIII, CCXCIV had to be made on the blood before
and after compression, which showed very clearly that the latter
contains more sugar than the former. Experiment CCXCIII proves
besides that this excess of sugar disappears at the end of some time.
So the sugar which comes from the liver is much less rapidly
broken down in the organism under the influence of compressed
oxygen than at normal pressure, so that it is stored up in the blood
to the point of producing glycosuria.
As to the production of the hepatic glucose itself, it is hampered
by the sufficiently prolonged action of oxygen at high tension, as
the following experiments prove.
750 Experiments
Experiment CCCIX. March 7. Albino rat.
Rectal temperature 39.6°.
Kept for three hours in compressed air at 12 atmospheres, above
a potash solution which absorbs the carbonic acid as it is formed.
Withdrawn suddenly, its rectal temperature is only 35.5°; it dies
quickly with air in its heart.
Its liver does not contain sugar; much glycogenic material.
Experiment CCCX. March 15. Albino rat; rectal temperature
39.9°.
At 12 atmospheres of air for 3 hours, with potash.
Withdrawn; temperature 37.2°; dies like the rat in the preceding
experiment.
No sugar in the liver.
In summary, consumption of oxygen, production of carbonic
acid and urea, breaking down of glucose in the blood, all chemical
phenomena which can be measured easily, appear to be consider-
ably slowed down by the action of oxygen under high tension. And
as these are the phenomena which determine the production of
heat, it is not surprising to see that the temperature of the animals
drops considerably. Nor is it astonishing to see that death is the
consequence of such a depression in the intensity of the physico-
chemical acts of nutrition.
But the violent excitation, the constant convulsions which ac-
company this death are still unexplainable by the depression alone;
still less explainable is the persistence of the symptoms after nor-
mal pressure has been restored. In fact, in studying diminished
pressure, we have noted a diminution of the chemical acts,
analogous to what increased pressure revealed, and yet the con-
vulsive struggling which precedes death by rapid decompression is
in no way comparable to the violent convulsions due to oxygen and,
furthermore, the return to free air marks irrevocably the end of all
these symptoms.
This shows then that during compression the regular chemical
acts of nutrition have been not only slowed up, but also modified; it
is supposable that the result of this deviation has been the forma-
tion of some substance capable of playing a toxic part, a substance
which, persisting after decompression, would continue to cause the
symptoms and might bring on death, a substance the elimination or
destruction of which would be necessary for a return to the state
of health.
The chapter especially devoted to the study of fermentations
will confirm us in this idea, and will even permit us to express it
with more precision and clarity.
Compressed Air; CX Poisoning 751
3. Aquatic or Invertebrate Animals.
The experiments reported up to this point were made only with
vertebrate air-breathing animals: mammals, birds, frogs. It was in-
teresting to study the action of oxygen at very high tension on in-
vertebrate air-breathing animals and on aquatic animals.
Experiment CCCXI. April 25. Beetles, flies, caterpillars; centi-
pedes; woodlice; arranged in two similar groups.
A. Placed in a corked flask; ordinary air, normal pressure.
B. In the compression apparatus, and taken to 6 superoxygenated
atmospheres; the pressure falls to 2 atmospheres.
April 26. All alive except the flies in B.
Experiment CCCXII. May 12.
Lizard; golden beetles; carpenter bee, loaded with mites; drone,
red fleas; flies; spiders; woodlice; centipedes.
At 5 o'clock in the evening, taken to 6 superoxygenated atmos-
pheres.
May 13; 10 o'clock in the morning, decompressed.
The drone, the flies, the woodlice are dead, as are several red
fleas; the others still move their feet a little, as does the carpenter
bee.
The lizard has spontaneous and excitable convulsions; he dies
some hours afterwards.
The beetles, the spiders, the mites, the centipedes are in good
condition and survive.
Experiment CCCXIII. May 14.
Golden beetle, bees, ants, red fleas, wood fleas; flies; woodlice;
spiders; snails; earthworms.
At 5 o'clock in the evening, placed in the cylindrical glass appara-
tus, with branches, earth, etc., to allow them to separate from each
other. Taken to 5 superoxygenated atmospheres.
May 15, 2 o'clock. All dead except the spiders, the earthworms,
which are twisted and intertwined, and the snails.
,A11 die in the open air.
Experiment CCCXIV. May 16.
A Capricorn beetle, 1 dragon fly, 1 blue butterfly, several bees,
drones, ants, red fleas, flies, syrphus flies; centipedes, geophiles; wood-
lice; spiders.
At 11 o'clock in the morning, taken to 5 superoxygenated atmos-
pheres; at 1 o'clock raised to 6; at 2 o'clock to 11 atmospheres.
Almost immediately all fall to the bottom, motionless, except the
ants and the centipedes, which run up and down.
The flies die in a half hour at most.
4 o'clock; none of the insects are moving. Decompression made.
The bees, the flies, the syrphus flies, and the butterfly are dead.
The Capricorn beetle, the dragon fly, the drones, the fleas, the ants,
the woodlice are still moving a little.
The myriapods and the spiders are in good condition.
752 Experiments
The next day, all are dead except the myriapods.
Experiment CCCXV. June 23.
Silkworm cocoons, sent by M. Raulin, from Alais, all of the same
day.
A. 12 are placed in an open bell-jar.
B. 6 in the cylindrical glass apparatus, at 5 superoxygenated
atmospheres.
C. (By some mistake, probably of the proof-reader, the conditions
in C were not given; the pressure was probably much higher than in
B. Translator.)
The air was changed every other day.
July 8. A. All have emerged.
B. No motion.
C. All dead; the skin of the chrysalises is not separable; they evi-
dently were killed very soon.
So the formidable influence of compressed oxygen is felt by in-
vertebrate animals as well as those belonging to the higher types.
The animals which in the simultaneous experiments first felt the
fatal effects of oxygen were the flies; after them the bees and the
butterflies; then the dragon flies and the fleas; considerably later,
the ants and the coleoptera (longicorn and carabic) . The woodlice,
and especially the arachnids (spiders, acaridae) and the myriapods
(centipedes, geophiles) are much more resistant. Then come the
earthworms and the snails, at least for length of life, if not for
lethal concentration.
The great importance of this kind of research is to show that
death from excess of oxygen does not depend upon a mechanism
peculiar to animals with red corpuscles, but is a general fact. There
is present a profound modification in the metabolism of the tissues.
We should note that these animals never seemed excited; on the
contrary, they quickly become motionless and fixed in some corner
of the apparatus, and die without showing any convulsion.
As a type of aquatic animal to be studied, I generally used young
eels, called "de la montee", the hearts of which one can easily see
beating.
Experiment CCCXV I. April 1. Small eels "de la montee", trans-
parent, temperature 15°.
A. 5 are placed in a well-corked test tube;
B. At three o'clock, 5 are placed in the cylindrical apparatus and
raised to 11 atmospheres of an air with 50% of oxygen. Oxygen ten-
sion 550, corresponding to about 26 atmospheres of air.
In the evening at 7:30, nothing particular apparent.
April 2, 1 o'clock. A: in good condition.
B: dead, stiff, not transparent, and not contractile when stimu-
lated electrically.
Compressed Air; 02 Poisoning 753
Experiment CCCXVII. April 2. Similar eels.
A: these are the same ones as A of the preceding experiment.
B: at 3 o'clock, 5 are placed in the apparatus at 5% atmospheres
of air with 57.5% of oxygen. The tension is therefore 316, correspond-
ing to 15 atmospheres of air.
April 3, 10 o'clock in the morning; A, very lively; when quiet,
respiratory rate 78 and pulse 40.
B: move when the apparatus is shaken, but not spontaneously.
Pulse 20 at the most; respirations, when eels are quiet, are not visible;
after they were shaken, I counted 22. From time to time, violent
struggling.
6 o'clock in the evening; in convulsions and are twisted in the
shape of an 8.
April 4, 1 o'clock. B: all dead, opaque.
Experiment CCCXVIII. April 4. Similar eels.
A: These are the eels of the two preceding experiments.
B: at 4 o'clock, 5 are placed under pressure of 10 atmospheres
of air.
April 5, 9 o'clock in the morning: A: very lively, 66 very ample
respirations; pulse 26.
B: at the bottom of the apparatus, hardly moving; respirations
invisible; pulse 20.
April 7. Same, all living; rapid decompression.
Experiment CCCXIX. July 8. Eels, not transparent.
At 5 o'clock in the evening, under compression of 10 atmospheres
of air containing 50% of oxygen; the apparatus is shaken to saturate
the water containing the eels.
July 9, 1 o'clock; all dead, opaque.
I tip the apparatus so that not the air but the water will escape;
this water, when collected in the syringe, froths, and is taken to the
mercury pump.
It contains 14 volumes of oxygen per 100 volumes of liquid, and
the same quantity of nitrogen.
Much weaker pressures are enough to kill aquatic animals
when their action is continued long enough.
Experiment CCCXX. May 20. Frog tadpoles, several days out of
the egg and in very good condition in the laboratory.
A: 5 in a little corked flask, with water, at normal pressure.
B: 5 in a flask with water, all in the glass compression apparatus,
at 7 atmospheres of air.
May 22: all living.
May 24: all living in A, all dead in B, probably since the day
before.
Experiment CCCXXI. May 24. Same experiment, with similar
animals; 7 atmospheres of air.
May 27; all the tadpoles in the compressed air are dead.
So aquatic animals are killed like air-breathing animals, when
754 • Experiments
oxygen is dissolved in the water in sufficient quantity. A pressure
of 15 atmospheres kills them quickly and they cannot live in 7
atmospheres. The transparency of the eels allowed us to note a con-
siderable slowing down of the heart beats, while the respirations
weakened so as to be almost invisible.
In another part of the book we shall draw conclusions from
these last experiments from the point of view of the physics of the
earth. It is enough here to note the generality of the fatal action
of compressed oxygen, which acts upon warm-blooded animals as
well as upon cold-blooded animals, upon vertebrates and inverte-
brates, upon animals which live in the water and those which
breathe air, upon adult animals and those in the process of develop-
ment. Chapters V and VI will permit us to extend this formula to
plants, to ferments, in a word, to every living thing.
Subchapter II
ACTION OF COMPRESSED AIR AT LOW PRESSURES
(FROM 1 TO 5 ATMOSPHERES)
The great interest attached to the toxic action of oxygen at
high tension has caused me, as I said when I began this chapter, to
begin this exposition as well as my research by a detailed analysis
of the effects of this poison of a new type. I confess that I have
long neglected, almost scorned, this study of the effects of slightly
compressed air which French and German doctors have so long
been testing, as we saw in the first part of this book. I could not,
however, help being somewhat interested in it. My researches even
gave it a new interest, unknown to former experimenters.
In fact, the experiments which have just been reported have
shown that poisoning by oxygen at high tension first checks the
intra-organic combustions, lessens the quantity of oxygen absorbed,
of urea excreted, and consequently lowers the temperature of the
body in warm-blooded animals. Now it is evident from the experi-
ments contained in Chapter III, that the same physiological effects
also result from diminished pressure, or, to speak more exactly,
from too low tension of the oxygen breathed.
Quite naturally then it was desirable to know where between
these two extremes, which are equally dangerous, is the point
where the organic combustions are at their maximum intensity.
Besides, it was proved by the same experiments that prolonged
Compressed Air; Low Pressures 755
exposure to a much rarefied air on the one hand, or to a very much
compressed air on the other is fatal to animals, even if the modifi-
cations of pressure are not such that they bring on the rapid symp-
toms of asphyxia or of poisoning by oxygen. It is very important to
determine what barometric pressure is most favorable to life. And
it is by no means proved that this favorable point coincides with
the maximum of combustion which we shall try to determine at the
same time; this even seems improbable a priori.
It was with the purpose of settling these two questions that the
experiments reported in the present subchapter were undertaken.
However, I must remind the reader again that I am acting as an
experimental physiologist and not as a hygienist or a doctor. To
study the continued effect of compressed air, I used the lower ani-
mals exclusively, because they are much better adapted to experi-
ments in which a prolonged stay in almost confined air is indis-
pensable, and because they do not present the physiological in-
equalities which so seriously complicate researches on the metabo-
lism of higher animals.
Everything seemed to indicate to me that the maxima which I
was seeking were included between normal pressure and 5 atmos-
pheres. This is suggested by graph A of Figure 22, which expresses
the oxygen content of the compressed and confined air in which
animals died without the interference of carbonic acid. It was be-
tween these limits then that I made my investigations.
In fixing these limits I had a reason of another sort, which is
also important. It was absolutely proved by the experiments on
diminution as well as on increase of pressure that the latter acts
only as modifier of the oxygen tension, so that an air rich in oxygen
and below one atmosphere in pressure produces the same effects as
an air poor in oxygen but sufficiently compressed. In the preceding
subchapter I repeatedly obtained the oxygen tension (02 x P) by
multiplying the factor pressure (P) by the factor of oxygen per-
centage (02) . So ordinary air at normal pressure has as its value,
from the point of view which interests us, 20.9; at two atmospheres,
this value becomes 2 x 20.9 = 41.8; at five atmospheres, 5 x 20.9 =
104.5. That is, one can use either ordinary air at two atmospheres
of pressure or air with 41.8% of oxygen under normal pressure (if
care is taken to remove the carbonic acid, the toxic acid of which
might complicate the symptoms) ; and ordinary air at 5 atmos-
pheres, or, obviously, pure oxygen.
This observation presents very great practical interest, because
it permits experimentation at normal pressure, that is, in material
756 Experiments
conditions easy to realize which do not require, as do high pres-
sures, the use of expensive and fragile glass apparatuses.
Finally, it seemed to me that I simply could not neglect these
modifications in the circulation and the respiration, which before
my time interested so many observers, whose statements, as we saw
in the historical part, are far from being always in harmony. I was
particularly anxious to measure the mechanical action of com-
pressed air, acting upon the gaseous reservoirs of the organism, that
is, the intestine and the lung.
In consequence, the experiments reported in this subchapter
will naturally be divided into two categories: in some, the super-
oxygenated air will act for only a short time, several hours, a day
at the most; in others, its action will be continued until it is ascer-
tained whether or not it has any effect.
1. Short Stay in Compressed Air.
A. Experiments Made Upon Myself.
I shall first report the experiments made upon myself with the
purpose of investigating on the one hand the respiratory and cir-
culatory phenomena, and on the other hand the action of com-
pressed air upon the excretion of urea, that is, upon one of the
evidences of intra-organic combustions.
For this part of my researches, Dr. Jourdanet lent me a chamber
which he has had made for therapeutic applications, and in which
an ingenious arrangement allows one to secure at will an increase
or a diminution in pressure.
This chamber, the general aspect of which is given in Figure 62,
measures 2.58 meters in height and 1.46 meters in diameter, and
consequently contains about 3*4 cubic meters of air; it is closed by
two doors, one inside and the other outside, on rollers guided by
grooves; these doors are fastened together, when they are closed,
by three long screws, which pass through holes cut through their
walls. As they are fitted tightly on the walls of the cylinder by
rubber gaskets, there is always one of them closed hermetically, for
compressed as well as for expanded air. A rubber tube communi-
cates with one or the other of the decompression or compression
pumps; communication with the outer air is secured by openings
which are not seen in the figure and which are controlled by inner
cocks, which the experimenter manages; another cock permits his
assistants to make the decompression if any accident happens to
him. On both the inside and the outside are precision thermometers
and manometers.
In this apparatus, operating at full speed, in one hour I can
Compressed Air; Low Pressures
757
reach one atmosphere of pressure above normal, at the same time
being under a current of pure air which is sufficiently strong to
keep the temperature in the chamber from rising more than 2 or. 5
degrees.
Fig. 62 — Apparatus of M. Jourdanet for the therapeutic use of compressed
or expanded air.
The number of heart beats was counted for five minutes, to
avoid causes of error against which often no precautions are taken.
The number of respirations was counted for 5 and often 10 minutes.
758 Experiments
To measure the quantity of air expired, I found nothing more
convenient or more accurate than a gasometer. The one I had made
especially for this purpose and which is pictured in Figure 63, has
several dials, by means of which one can estimate the volume of
air which has passed through the apparatus to within 50 cc.
Fig. 63 — Gas meter for measuring respiratory movements.
When it was necessary to measure the maximum expirations, I
stood up, with my garments loosened, and after the inspiration, I
took in my mouth, without any supplementary tube, the pipe leading
to the gasometer and exhaled rather slowly until the lungs were
empty, my nose, of course, being closed tightly by my left hand; I
thus made at least 10 expirations, of which I took the average.
The same arrangement was used when I wished to exhale into
a rubber bag to check the quantity of carbonic acid produced in a
given time. I generally breathed for 10 minutes into the bags; then
the air from them was passed for a whole night through the potash
bubblers which I shall describe later; there it was completely freed
Compressed Air; Low Pressures
759
of its carbonic acid; the potash solution was then analyzed in the
mercury pump.
But to measure the regular respirations, the arrangement was
more complicated; I had to have an apparatus which operated
without the least attention, for we know how easily the respiratory
movements are modified, when one wishes to examine them. The
arrangement in Figure 64 gives excellent results, as many test ex-
periments have shown me.
A rubber mouthpiece, which is applied to the dental arches and
760 Experiments
which the lips support without inconvenience or effort, is con-
nected by a large rubber tube and a Y-shaped piece of copper to
two glass tubes, each of which contains a membraneous valve, like
those used by MM. Denayrouze in their well-known apparatuses;
these valves are excellent, very delicate, and hold very well, if they
are kept wet. As they are placed in opposite directions, one per-
mits only the intake of inspired air, the other the escape of expired
air, which a rubber tube suitably placed conducts to the gasometer.
Of course the nose is closed the whole time by a sort of pincer to
which one easily becomes accustomed.
I breathed thus for 10 and sometimes 20 minutes, remaining in
perfect calmness, reading, and merely looking at the time or count-
ing my respirations; sometimes the assistant did this for me, look-
ing in through one of the glass portholes.
Besides, I regulated all the other conditions of my life very care-
fully; every day I went to the laboratory and sat there from 2 to 6
hours in or out of the apparatus; I took no other exercise.
It was with all these precautions that the following experiments
were carried on.
Experiment CCCXXII. November 6. I begin by putting myself
regularly on the following diet, which previous tests showed me was
suitable. My weight is 73 kilos; height, 1.73 meters.
At lunch (12:15); two medium sized eggs, 70 gm. of lean mutton,
140 gm. of bread, 800 cc. of a mixture half wine and half water.
At dinner (7 o'clock) : 120 gm. of lean beef, 200 gm. of mashed
potatoes, 6 brandied cherries, bread and wine as at lunch.
November 7. After having emptied my bladder at noon, I keep
my urine until Nov. 8, at noon .... A
I do the same the following days.
This day I remain at normal pressure.
November 8. I place myself in the cylinder from 3 o'clock to 6
o'clock; but I keep a current of air at normal pressure.
Urine from Nov. 8 to Nov. 9 B
November 9. Seated at 2:45 in the open apparatus; pulse 78;
respiratory rate 8; maximum expiration 3.7 liters.
At 3:18, compression begun.
At 3:45, pressure +30 cm.
At 4 o'clock, pressure +45 cm.; pulse 80; maximum expiration 4
liters.
At 4:12, pressure +53 cm.
At 4:42, same pressure; pulse 72.
At 5:10, same pressure; respiratory rate 8.2; maximum expiration
4 liters.
At 5:32, the pressure was maintained at the same level; I begin
the decompression; I leave the apparatus at 6:53.
At normal pressure, maximum expiration 3.7 liters.
Compressed Air; Low Pressures 761
Urine from Nov. 9 to Nov. 10 .... C.
November 10. Seated in the apparatus at 2:35.
Maximum expiration 3.8 liters; calm respiration is 7.6 per minute,
equivalent to 6.3 liters, or 0.83 liters for each expiration; pulse 68.
Closed the doors at 2:55.
At 3:20, compression of +37 cm.; maximum expiration 3.8 liters.
At 3:38, +56 cm.; maximum expiration 4 liters.
At 3:50, same pressure; 8.1 respirations per minute, equivalent to
6.7 liters, or 0.82 liters per expiration.
At 4:25, same pressure; calm expirations give 6.2 liters per minute,
without counting the number.
At 4:50, same; 6.5 liters per minute.
At 5 o'clock, the same; pulse 69.
At 5:10, the same; maximum expiration 4 liters.
At 5:37, the same; began the decompression.
At 5:45, pulse 63.
At 6:15, pressure +15 cm.; pulse 60.
At 6:20, pressure +10 cm.; calm expirations give 6.2 liters per
minute.
Normal pressure at 6:30.
Urine from Nov. 10 to Nov. 11 .... D
November 11. End of the experiment at noon.
The urine was analyzed by the Grehant method, but the analysis
was lost.
Experiment CCCXXIII. November 15. I enter the apparatus with
a rather severe cold in the head, a cough, and tracheal pains showing
the beginning of a cold in the chest.
At 2:40, at normal pressure, my maximum expiration gives 3.75
liters.
At 2:50, pulse 77.7.
From 2:55 to 3:05 ,breathed quietly into a bag .... A
Ordinary expirations as reckoned on the gasometer give 6.5 liters
per minute.
Respiratory rate 9.
At 3:10, compression begun.
At 3:55, compression of +52 cm.; pulse 65.
At 4 o'clock, compression +60 cm.; maximum expiration 4.08
liters.
At 4:20, compression +56 cm.; respiratory rate 7.5.
At 4:30, same; pulse 62.5.
Calm expirations give 5.86 liters per minute.
From 4:45 to 4:50, breathed quietly into a bag . . . . B
At 4:52, began the decompression.
At 5 o'clock, pressure +40 cm.; calm expirations give 5.93 liters
per minute.
At 5:15, pressure +32 cm.; the snuffles which had left me begin
again as does the heaviness in the head; some minutes after, (pres-
sure +20 cm.) the cough reappears.
At 5:55, normal pressure. Pulse 65; the pulmonary ventilation
gives 6.28 liters per minute; maximum expiration is 3.8 liters.
762 Experiments
The cold in the head stops in the night and the cold in the chest
disappears.
Gas A gives for 10 min. 2.643 liters of C02, that is, for 1 hour 15.858 liters
Gas B gives for 10 min. 2.710 liters of CCX, that is, for 1 hour 16.260 liters.
Experiment CCCXXIV. December 17. Barometric pressure 74 cm.;
I begin again the diet of Experiment CCCXXII.
The urine was collected from noon December 17.
December 11. Remained at normal pressure.
Urine from Dec. 17 to Dec. 18 noon .... A
December 18. At normal pressure, from 2:30 to 3 o'clock, the
maximum expiration is 3.76 liters; quiet pulmonary ventilation is
6.54 liters per minute; pulse 81.
At 3 o'clock, began the compression.
At 3:44, compression +48 cm.; the maximum expiration gives
3.96 liters.
At 4:30, same pressure; pulse 79; pulmonary ventilation 6.74 liters
per minute; 8.3 average respirations per minute.
At 5:12, compression -4-52 cm.; decompression begun.
At 6: 15, normal pressure; pulse 59; 8 average respirations; maxi-
mum expiration 3.81 liters.
At 7:30, pulse 60.
At 8:15, pulse 83.
Urine from Dec. 18 to Dec. 19 at noon . . . . B
December 19. Barometric pressure 74 cm.
At 9:30 in the morning, pulse 64, and respiratory rate 8; at noon,
same.
At 2 o'clock, still normal pressure, pulse 68.
At 2:20, compression begun.
At 3:10, compression -(-45 cm.
At 3:35, compression +54 cm.
At 3:50, compression +56 cm.; pulse 82; maximum expiration 3.92
liters.
At 4 o'clock, same; began the decompression.
At 4:45, compression +37 cm.
At 5:50, normal pressure; pulse 68; maximum expiration 3.80
liters.
Urine from Dec. 19 to Dec. 20, at noon . . . . C
December 20, pressure 74 cm.
At 4 o'clock, normal pressure; pulse 85; respiratory rate 6.5.
At 4: 10, began the compression.
At 5:10, compression +50 cm.; 6.6 calm expirations; I begin the
decompression.
At 5:30, compression +41 cm.; pulse 66; 6 respirations.
At 6:15, normal pressure; pulse 58; 5.6 calm expirations per
minute.
Urine from Dec. 20 to Dec. 21, at noon . . . . D
December 21, normal pressure; same diet.
Urine from Dec. 21 to Dec. 22 at noon . . . . E
December 22, normal pressure; same diet.
Urine from Dec. 22 to Dec. 23, at noon . . . . F
Compressed Air; Low Pressures
763
The analysis of the urines by hypobromite of soda gives:
A (normal pressure) 1650 cc. containing 20.15 gm. of urea.
B (compressed air) 2010 cc. containing 24.72 gm. of urea.
C (compressed air) 1990 cc. containing 26.04 gm. of urea.
D (low compression) 2255 cc. containing 21.18 gm. of urea.
E (normal pressure) 2080 cc. containing 20.80 gm. of urea.
F (normal pressure) 2125 cc. containing 22.50 gm. of urea.
Experiment CCCXXV. February 9. M. Regnard, one of my assist-
ants, 27 years, weighing 75.5 kilos, height 1.83 meters.
At 1:45, normal pressure; pulse 70; respiratory rate 15.6; pulmon-
ary ventilation of 12.28 liters per minute. Maximum expiratory
capacity 4.15 liters.
At 2 o'clock, began the compression.
At 2:45, compression of +52 cm., left until 4 o'clock. At that time,
pulse 57, respiratory rate 14.6; pulmonary ventilation 13.22 liters;
maximum expiration 4.64 liters.
At 4:20, began the decompression.
At 5:30, normal pressure; pulse 56; respiration 16; pulmonary
ventilation 13.02 liters; maximum expiration 4.60 liters.
Let us see now in summary what these experiments have given
us in regard to each important physiological function. The follow-
ing table will aid our survey.
Table XVI
1
2 3 4 5
6 7 8 9 10 11 12 13
Before the compression
During the compression
After the compression
G
E
a
P
. 5 -
3
3
Experiment
o>N
1 r
i>§
6 c
o>%
R r
numbers
« C
ao
4>m
cues
Si
01
P
CA o
2 <u u
0)
"3
J. C
ao
in 13
1*5
3^3
2 as
WSffl
2 <u u
0)
3
«2
liters
liters
a,
k2
liters
liters
0,
«2
liters
liters
CU
CCCXXII
CCCXXII
CCCXXIII
CCCXXIV
CCCXXIV
CCCXXIV
I 78
I 7.6 |
13.7
6.3 [3.8 |68
I 9 | 6.5 I 3.75 I 78
| | 6.54 |3.76 |81
__|____| |68
■5 1 | ___ 1 85 | 6.6 |
8.2
8.1
7.5
8.3
|4.0 |72|____ | . |3.7 I
6.5 | 4.0 I 69 I
5.86 | 4.08 | 62 |
6.74 | 3.96 | 79 |
, | 3.92 ! 82 |
- I - I -
6.2 | .___ I 60
_ | 6.28 | 3.8 I 65
8 I |3.81|59
| I 3.80 | 68
5.6 I f I 58
Averages
CCCXXV
I 7.7 | 6.4 | 3.75 | 76
I 15.6 112.28 14.15 I 70
| 7.7 | 6.4 | 3.99 | 73
I 14.6 | 13.22 I 4.64 I 57
16.
| 6.2 |3.78|62
I 13.2 I 4.60 I 56
Respiration. The number of respirations (Columns 2 and 6),
which is, as we know, always very difficult to measure exactly on
one's self, has sometimes slightly increased, sometimes diminished;
the average is the same for compressed air and for normal pressure
at the beginning; I do not count Column 10 in which only two fig-
ures are listed.
The amount of pulmonary ventilation (Columns 3 and 7), that
is, the quantity of air which passes through the lungs during a
minute when the respirations are calm, also remained the same.
764 Experiments
We may conclude that variations are in a general way very slight.
This point, which had not been clearly determined by the authors
who preceded me, is of great importance, as we shall show later.
Finally, my experiments show, as all observers had already noted,
a considerable increase of the maximum pulmonary capacity (Col-
umns 4, 8, 12) . On the average, the strongest expiration which I can
make rose from 3.75 liters to 3.99 liters; this is an increase of 240 cc.
that is, 6.9%. In M. Regnard it was 450 cc, or 11%. After the de-
compression I rapidly returned to the normal state.
Circulation. The average pulse rate decreased considerably dur-
ing the stay in compressed air; from 76 at the beginning, it became
73 at the maximum of the compression and 62 when I left the cylin-
der.
But I must say that the apparent clearness of this result is de-
cidedly lessened by the fact that at normal pressure my pulse, when
taken at the same hours, that is, at the same time after lunch and
after a seated rest of several hours, gave variations which were ab-
solutely of the same order.
Metabolism. My experiments are very few; but they have been
conducted with the greatest physiological precautions. The analysis
of the air expired quietly for 10 minutes gives me (Experiment
CCCXXII) for one hour at normal pressure 15.858 liters of carbonic
acid; at the maximum of the compression (56 cm.), it gave 16.260
liters, an increase of 0.418 liters, or 26%.
The production of urea (Experiment CCCXXIII) gave a more
interesting result; under the influence of compressed air, it in-
creased considerably (from 20.15 gm. it rose to 24.72 gm., then to
26.04 gm.) to fall again under normal pressure to amounts near its
original rate (21.18 gm.; 20.80 gm.; 22.50 gm.). So that, on the aver-
age, at normal pressure it was 21.9 gm. and rose to 25.3 gm. in air
compressed to -4- 53 cm.
I shall take the opportunity, in the third part of this book, to
compare these figures with those obtained by M. G. Liebig and
M. Pravaz in recent investigations.
B. Production of Urea: Experiments on Dogs.
I tried again to measure the modifications caused in the produc-
tion of urea by experimenting on dogs. I kept them, of course, on a
strict diet; the urine was collected by catheterization once every
24 hours and added to what the animal voided spontaneously.
Here are the results of one of these experiments, which no
accident hindered.
Compressed Air; Low Pressures 765
Experiment CCCXXVI. February 9. Dog weighing 10.8 kilos, kept
on a diet and used to staying in cages and in the compressed air
apparatus in Figure 33.
February 12 at 6 o'clock in the evening, catheterized.
February 13. Remained at normal pressure; catheterized at 6
o'clock in the evening; in 24 hours gave 650 cc. of urine .... A
February 14. From 9 o'clock in the morning to 5:45, kept under
current of air at the total pressure of three atmospheres. Catheterized
at 6 o'clock; gave in all 610 cc. of urine B
February 15. Same pressure; urine of 24 hours, 1080 cc C
February 16. Normal pressure; urine of 24 hours, 1350 cc D
February 17. Normal pressure; urine of 24 hours, 1370 cc E
Analysis of urine by the Yvon method.
A (normal pressure) contained 7.9 gm. of urea.
B (3 atmospheres) contained 10.4 gm. of urea.
C (3 atmospheres) contained 9.0 gm. of urea.
D (normal pressure) contained 9.1 gm. of urea.
E (normal pressure) contained 8.4 gm. of urea.
It is quite evident that since the catheterization was made im-
mediately after the decompression, urine D contained a part of the
products of katabolism formed during the stay in compressed air;
it ought therefore to be included in the urine of the compression.
Taking this into consideration, we see that the urea increased as a
result of the daily stay of 9 hours in air at 3 atmospheres; indeed,
it rose then on the average to 9.5 gm., while at normal pressure it
was on the average only 8.1 gm.
C. Chemical Phenomena of Respiration.
I made a certain number of attempts to estimate the quantity of
carbonic acid formed by an animal placed sometimes at normal
pressure, sometimes at increased pressure without exceeding 5
atmospheres. But I encountered experimental difficulties which
prevented me from reaching a conclusion.
To obviate these difficulties, instead of compressed air I used
superoxygenated air, and adapted slightly the apparatus set up in
my laboratory by my two assistants, MM. Jolyet and Regnard, an
apparatus which is both a simplification and an improvement of
the Regnault and Reiset apparatus.
Here is a short description of it, which Figure 65 will allow the
reader to follow easily.
The experimental animal is placed under the bell C, which is
provided with a thermometer t, a manometer m, and a little rubber
bag v, intended to offset the influence of outside modifications of the
barometric pressure, which must be taken into account in experi-
ments which may last several days.
766
Experiments
The air of this bell is constantly purified of the carbonic acid
produced in it by the respiration of the animal, by action of pipettes
P and P' and the washbottle A. Bottles and pipettes contain a very
much concentrated solution of potash, the C02 content of which
was previously determined by the mercury pump and an acid; they
Jjg
T3 c
3
o £
jC a;
o cc
a o
I
are operated by a little water motor M, and a set of pulleys and
eccentrics which can be understood by a mere inspection of the fig-
ure; the agitation of flask A is so energetic that it seems filled with
foam. The air which passed through the alkaline solutions follow-
ing the course iP'PpAp'K, returns to the bell absolutely freed
of its CO,.
Compressed Air; Low Pressures 767
But the animal consumes oxygen, and consequently there is a
tendency towards a diminution of pressure in the apparatus. Now
pure oxygen, obtained by decomposition of water by a battery, is
contained in the graduated flask O, and by means of an apparatus
with constant level H, filled with a concentrated solution of calcium
chloride, the oxygen comes bubble by bubble to replace what was
removed by respiration.
When the experiment is over, a simple reading on the graduated
bell gives the quantity of oxygen consumed; for the carbonic acid
produced, the potash solution is collected, and analyzed in the pres-
ence of an acid in the vacuum of the mercury pump.
Experiment CCCXXVII. Rat weighing 360 gm., accustomed for
about ten days to living in the bell under a current of air, with its
food and its box.
1.) December 23, at 3 o'clock, the experiment begins in ordinary
air.
At the end of 24 hours, the experiment is stopped; we find that
the animal has consumed 12.360 liters of oxygen, and formed 7.310
liters of carbonic acid.
The temperature of the rat before the experiment was 38.5°;
afterwards it was 38°.
2.) December 25, at 4 o'clock, a current of oxygen is passed
through the bell in which the rat is kept and through the apparatus.
Then, since the system is closed, the pipettes are operated for a quar-
ter of an hour to mix the air of the different receivers. Then a sample
is taken which gives 87.5% of oxygen.
After 24 hours, experiment stopped; the oxygen consumption was
11,352 liters; the carbonic acid production was 6.964 liters.
Temperature of the rat: before, 38°; after, 37.5°.
3.) January 3, at 3 o'clock, performed the experiment again in
ordinary air.
In 24 hours, the oxygen consumption was 12.840 liters; the pro-
duction of carbonic acid 6.820 liters.
4.) January 5, at 3 o'clock, experiment in air with 48.7% of
oxygen.
In 24 hours, the oxygen consumption was 13.724 liters; the car-
bonic acid production 10.320 liters.
Summarizing, if we change oxygen percentages to their equiva-
lents in barometric pressure, we shall say that there were
At 1 atmosphere, 12.60 liters of oxygen consumed, 7.06 liters of
CO, formed.
At 2.3 atmospheres, 13.72 liters of oxygen consumed, 10.32 liters of
CO; formed.
At 4.2 atmospheres, 11.35 liters of oxygen consumed, 6.96 liters of
C02 formed.
768 Experiments
The activity of organic combustions then increased at first, and
then diminished, after passing a certain maximum which is prob-
ably above 2 atmospheres.
Cold-blooded animals gave me a similar result. But for them it
was not necessary to use such a complicated apparatus, considering
the low level of their respiration. The arrangement of the equip-
ment was the same as in the experiments made on tissues (Chapter
VI), represented in Figure 74; the animal was placed in the flask,
raised on a little tripod which prevented it from touching the pot-
ash solution.
Experiment CCCXXVIII. January 11. Three frogs (A, B, C), nim-
ble and healthy, are placed each in one of these apparatuses. The
temperature is 15°.
A weighs 28 gm. and is placed in ordinary air;
B weighs 20 gm., air with 56.3% of oxygen;
C weighs 20 gm.; air with 92.5% of oxygen.
The animals are left in these conditions until January 15.
We then made the analysis of the potash solutions and read the
graduated bells. The result was
A consumed 205 cc. of oxygen and produced of CO=.
B consumed 157 cc. of oxygen and produced 71.8 cc. of CO2.
C consumed 114 cc. of oxygen and produced 62.8 cc. of C02.
If we take account of the different weights of these different
animals and if we reduce them all to 20 gm., we see, when we reduce
the oxygen content of the air to corresponding values in barometric
pressure, that there was:
At 1 atmosphere, 146 cc. of oxygen consumed and of C02 pro-
duced.
At 2.7 atmospheres, 157 cc. of oxygen consumed and 71.8 cc. of CO?
produced.
At 4.4 atmospheres, 114 cc. of oxygen consumed and 62.8 cc. of CO:
produced.
This experiment brings us to the same conclusions as the preced-
ing in regard to the intra-organic combustions.
D. Pulmonary Capacity.
The experiments which I reported some pages back corroborated
the statement of the earlier authors that the maximum inspiration
is greater in compressed air than at normal pressure.
Since this modification is rather considerable and since it is the
instantaneous result of the increase of the ambient pressure, I was
led to believe that it is due to a mechanical action, acting, of course,
upon the only compressible part of our body, that is, the intestinal
gases. The mere diminution in volume of these gases should, in my
opinion, have as its result an increase of the thoracic cavity, since
Compressed Air; Low Pressures 769
the diaphragm drops at the same time as the abdominal wall, fol-
lowing the retreat of the intestines.
For the purpose of confirming this and of measuring the in-
crease thus gained, I made the following experiment:
A dog was killed by section of the medulla; immediately after,
his thoracic capacity was measured by the accurate procedure de-
vised by M. Grehant; 5 then there was introduced into his
trachea a tube in the shape of a Y, one of the branches of which
opens into the air, while the other communicates with a rubber bag
carefully emptied of air; two valves arranged in opposite directions
permit the outer air to enter by the first branch, whereas it cannot,
once it has entered the lungs, escape except through the second
branch into the bag. When these arrangements had been made,
the body of the animal was placed in a compression apparatus. Its
lungs, in communication with the air, could undergo the changes
in capacity the existence of which we were seeking to verify. Then
a sudden decompression was made; the air in the lungs, which was
then in excess, escaped and lodged in the bag, where we could
measure its volume, which would indicate whether there was an
increase in the thoracic capacity.
Here is the simple formula which serves to find and calculate
this increase.
Let us call the pulmonary capacity at normal pressure C, the
compression (total number of atmospheres) to which the animal
was subjected P, and the volume of air found in the bag after the
C + V
decompression V. It is evident that the formula will repre-
P
sent the pulmonary capacity during the compression, and the com-
parison of the number thus obtained with C will show the value
of the increase.
When this had been established, I ligated the intestinal tube at
its two ends, anus and esophagus, and collected the gases from it
under water; it was interesting to see the relation between their
volume and that of the thoracic variations.
Experiment CCCXXIX. June 27. Dog of 4.250 kilos, which had
just been poisoned by curare.
It was placed, prepared as was just explained, in the cylindrical
apparatus, and the pressure was raised to 3 atmospheres; after the
decompression there were 260 cc. of air in the bag.
The lungs and trachea of the animal, carefully extracted, and
macerated under water, after being cut into pieces so small that the
fragments sank to the bottom of the water, gave up only 115 cc. of air.
770 Experiments
There was, therefore, a 15 cc. increase in volume.
The digestive tube contained 60 cc. of gas, 45 cc. of which was
in the small intestine. At 3 atmospheres, the volume would be only
20 cc. So the 40 cc. decrease was filled about one third by the
diaphragm and two thirds by the abdominal wall.
Experiment CCCXXX. June 28. Dog weighing 8.7 kilos, killed by
section of the medulla.
The pulmonary capacity was 300 cc.
After the pressure had been raised to 3 atmospheres, there were
750 cc. in the bag.
According to the formula given above, the increase in the tho-
racic capacity was 50 cc.
The compression was begun again and raised to 6 atmospheres.
At the decompression there were in the bag 2000 cc; the increase in
this case was 83 cc.
There were in the alimentary canal 160 cc, which at 3 atmospheres
was reduced to 53 cc. (decrease of volume: 107 cc), and at 6 atmos-
pheres amounted to only 27 cc. (decrease: 133 cc).
Experiment CCCXXXI. July 3. Dog weighing 8.4 kilos, killed the
day before.
The pulmonary capacity was 369 cc.
Compression made to 100 cm. of mercury (total pressure). The
bag then contained 157 cc.
The real volume is derived from the proportion 100 : 76 =
(369 cm. + 157 = 526 cc.) : x = 399 cc; that is, an increase of 30 cc.
Experiment CCCXXXII. July 13. Dog weighing 6.63 kilos.
The pulmonary capacity is 196 cc.
Compression made to 3 atmospheres, then there was in the bag
512 cc. of air.
The pulmonary capacity then was 236 cc; an increase of 40 cc.
Experiment CCCXXXIII. July 26. Dog weighing 5.5 kilos, killed
by curare.
Pulmonary capacity 232 cc.
Taken to 3 atmospheres; the bag contained 627 cc; the capacity
then was 286 cc, an increase of 54 cc
Taken to 6 atmospheres; the bag contained 1535 cc; therefore the
capacity was 294 cc, or an increase of 62 cc.
So our anticipation was realized; the pulmonary capacity in-
creased in compressed air, by a simple physical effect, without any
active intervention of the respiratory muscles. But this increase
represented only a fraction of the decrease in volume of the in-
testinal gases. Furthermore, my experiments show that it is far
from increasing proportionally to the pressure; so in Experiment
CCCXXX, at 3 atmospheres it was 16% of the initial capacity, and
at 6 atmospheres only 26%; in Experiment CCCXXXIII, at 3
atmospheres, it was 23%, and at 6 atmospheres only 26%; even
Compressee Air; Low Pressures 771
more, in Experiment CCCXXXI, with only a third of an atmos-
phere, it was 8%. That is easily understood, because in its descent
upon the abdomen the diaphragm must meet more obstacles than
the walls of the belly.
E. Intra-Pulmonary Pressure.
We have known for a long while that at the beginning of the
inspiration, the air contained in the chest is a little rarefied, and
that it is a little compressed at the beginning of the expiration, that,
in other words, as I have said elsewhere, "the glottis does not suf-
Fig. 66 — Apparatus for the observation of variations of the intrapulmonary
air tension.
fice for the output of the respiratory pump." Are these variations
in the intra-pulmonary pressure, which have such an important
influence on the course of the blood the same in compressed air as
in normal air? We have seen that Pravaz did not hesitate to con-
sider them increased; but he did not furnish, any more than
Vivenot and the other doctors who adopted his opinion, any ex-
perimental proof to support his word. To study this difficult ques-
tion, I used an experimental method which I published long ago.6
An animal is placed under a tubular bell which is well ground
to fit its base (Figure 66), through the stopper of which passes an
elbow tube, which is attached to a Marey polygraph by a rubber
772
Experiments
tube. The oscillations of the needle, which correspond to the re-
spiratory movements, are, as I have shown, caused by the changes
of the intra-thoracic pressure, and their size gives a relative meas-
ure of it.
It is very simple then to examine the tracings one obtains, either
at normal pressure or in compressed air. The only precautions to
Compressed Air; Low Pressures
773
be taken are to ventilate the bell properly before inserting the
stopper, to make a record only when the animal is very calm, and
for compressed air, to avoid variations of pressure during the
recording.
Experiment CCCXXXIV. February 12. A cat is placed under the
bell.
At normal pressure it gives the tracing in Figure 67.
We take it into the compression cylinder and in about an hour,
reach a compression of +53 cm. (total pressure 128 cm.) We then
obtain the tracing in Figure 68.
Examination of these two tracings shows: 1) that the number
of respirations has diminished (in the proportion of 10 to 7) ; 2) that
the amplitude of the oscillations has likewise diminished, that is,
that the variations of the intra-thoracic air pressure were less in
compressed air than at normal pressure.
F. Arterial Pressure.
The increase of the arterial pressure under the influence of com-
pressed air has been admitted on the strength of the sphymographic
tracings of Vivenot; but no direct experiment had been made, or
rather had succeeded, in the aim of ascertaining by the manometer
the direction and the amount of the modification.
I have tried to fill this gap by the following experiments.
Experiment CCCXXXV. February 17. Dog of average size, new
subject, fastened upon the dog board.
Ludwig's recording manometer, attached to a cannulated femoral
artery, gives the tracing of Figure 69, in which the low points are
5.5 cm. above the zero line, which indicates a pressure of 11 cm., and
Fig. 69 — Tension of the blood in the femoral artery. Normal pressure.
Fig. 70 — Tension of the blood in the femoral artery. Compressed air.
774 Experiments
the highest points at 6.7 cm., or a pressure of 13.4 cm., so that the
amount of the respiratory oscillation is 2.4 cm., and the average pres-
sure L2.2 cm.
The animal is then placed in the compression apparatus, and a
pressure of +53 cm. is reached in 45 minutes. Then we obtained with
the same artery the tracing in Figure 70; low pressure 12 cm.; high
pressure 15.6 cm.; average 13.8 cm.; amount of oscillation 3.6 cm.
Fig. 71 — Tension of the blood in the carotid artery. Normal pressure.
Fig. 72 — Tension of the blood in the carotid artery. Compressed air.
Fig. 73 — Tension of the blood in the carotid artery. Normal pressure.
The pulse rate dropped from about 216 to 200, and the respiratory
rate from 41 to 29 per minute.
Experiment CCCXXXVI. February 23. Large dog, new subject,
strong, in which a subcutaneous injection of 10 eg. of chlorhydrate
of morphine had been made to quiet its constant struggling. It slept
during the entire experiment.
At normal pressure we obtained the tracing of Figure 71 from a
carotid artery.
After the doors had been closed and the pressure raised in three
quarters of an hour to 53 cm., we got the tracing in Figure 72.
Finally, after return to normal pressure in 5 minutes, we traced
Figure 73.
Compressed Air; Low Pressures 775
The experiment is summarized as follows.
Minimum Maximum Average Respiratory Number of
Pressure Pressure Pressure Oscillations Respirations
Tracing A 5.2 cm. 7.2 cm. 5.8 cm. 3 to 10 mm. 48
Tracing B 8.8 cm. 13.4 cm. 10.4 cm. 16 to 23 mm. 28
Tracing C 8.0 cm. 11.0 cm. 9.8 cm. 3 to 14 mm. 40
Now comes the question: What is the reason for these variations
in the circulatory phenomena? Should they be attributed to the
action of the superoxygenated blood on the heart and the nervous
system which controls this organ and the movements of respira-
tion? Or, on the contrary, are they the consequence of the decrease
in volume of the intestines, reacting on the play of the intra-
thoracic organs?
We might discuss this point at length. The surest method is to
experiment. If we take the arterial pressure tracings of a dog
which breathes first ordinary air and then air with an oxygen con-
tent of about 35%, which corresponds nearly to the tension obtained
in our compression apparatuses, we find that in spite of a certain
slowing down of the respiratory movements, when the animal is
breathing the superoxygenated air, the arterial pressure is not mod-
ified, and that the play of the thorax influences it equally in both
cases.
It becomes evident by comparison of these results that:
1). The pressure of the blood (maximum, minimum, average)
has increased in compressed air;
2) . The variation due to the respiratory influence has increased
considerably in compressed air, which is contrary to the conclusions
of Vivenot, which were based, moreover, on observations made on
emphysematous patients;
3) . These variations were accompanied by a slowing down of
the respiration;
4) . They are due not to the action of the oxygen absorbed in
greater quantity by the blood, but to the pressure, as an agent of
the mechanical type.
2. Prolonged Stay in Compressed Air.
In this second section I shall enumerate the experiments which
were designed to determine whether a slight increase in the oxygen
tension can act favorably or unfavorably on the life of animals, on
their development, in a word, on the phenomena of their existence
as a whole, outside all physiological analysis. To study this im-
portant question, I experimented upon eggs, cocoons, small air-
776 Experiments
breathing or aquatic animals; I used sometimes compressed air, but
more often, for ease in arranging the experiments, air in which
the oxygen content had been increased.
Let us now discuss the experiments.
Experiment CCCXXXVII. July 31. Placed in two large balloon
flasks, a certain number of fly pupae of the same age.
A, the balloon flask is full of air.
B, the balloon flask is full of oxygen.
August 9. 6 emergences of flies in A, none in B.
August 10. All emerged in A, almost all in B.
Experiment CCCXXXVIII. June 23. Silkworm cocoons, of the
same day (this experiment was made at the same time as Experiment
CCCXV).
A, 12 were placed under an open bell.
B, 12 in a flask of 3 liters, at a pressure of 2 atmospheres.
C, 6 in a Seltzer water receiver with a capacity of 1 liter, at 5
atmospheres of air.
The air in B and C was changed every other day.
July 8. A, all emerged.
B, all the chrysalises were very active; 2 were transformed but
remained in their cocoons.
C, the chrysalises were motionless; but when the skin was re-
moved from some of them, the butterfly was almost complete, with
some reflex movements.
B and C were placed in the open air.
July 15. B, one butterfly out of the cocoon and alive; a few others
transformed, but remaining in the cocoon and dead; under the skin
of the remaining chrysalises, the butterfly was found ready to emerge,
but dead.
C, all the chrysalises were dead, without having made any move-
ments in the open air; under the skin of the chrysalis, the butterflies
were downy, but not far advanced.
Experiment CCCXXXIX. April 15. Frog eggs already some-
what bilobed, placed in equal numbers in a similar quantity of water;
in addition, 5 tadpoles which had emerged 4 days before.
A and A', under closed bells, ordinary air.
B and B', under bells with 95% of oxygen, recently prepared by
chlorate of potash, well washed over potash and having remained
2 hours over pure water.
These 4 bells were inverted over plates full of water and I
placed in the water outside, several tadpoles which were to serve
as controls.
April 25. A and A', all emerged and very lively.
B and B', all dead, after the eggs had developed almost to the
point of emerging.
The controls are all in good shape.
Compressed Air; Low Pressures 777
Experiment CCCXL. April 28. Frog tadpoles that had emerged
8 or 10 days before, in equal numbers.
A, A', bells inverted over water, full of ordinary air.
B, B', bells arranged in the same way, filled with 95% oxygen,
well washed.
Controls outside the bells as in the preceding experiment.
May 1. All living.
May 3. The controls and the tadpoles in A and A' are living;
those in B and B' are all dead.
Experiment CCCXLI. May 8. Tadpoles; experiment prepared like
the two preceding, with the same oxygen kept over very clean water.
May 10, two tadpoles dead in the oxygen.
May 11, all dead in the oxygen, all alive in the air.
Experiment CCCXLII. April 26. Frog eggs, not yet bilobed. In
equal numbers, in the same quantity of water, under closed bells.
A in ordinary air.
B in air containing 24% of oxygen.
C in air containing 28% of oxygen.
D in air containing 51% of oxygen.
E was to contain at least 80% of oxygen; but the analysis could
not be made on account of an accident.
May 4. A, large number of tadpoles emerged.
B, almost as many as in A.
C, far less.
D, only 5 or 6.
E, only 2.
Later (bell E having been turned over), the development became
equal.
May 21, all the tadpoles in all the bells are well and similar.
Experiment CCCXL1II. May 28. Frog tadpoles; water.
A, in 'flask in probably 90% of oxygen.
B, in glass apparatus at 5 atmospheres of ordinary air.
The tadpoles in B die May 30.
Those in A die May 31.
Experiment CCCXLIV. June 2. Little eels "de la montee"; placed
3 in each jar.
A, under bell full of air.
B, under bell with more than 90% of oxygen.
C, in the glass apparatus, at 5 atmospheres of ordinary air.
June 4. A, all alive.
B, 1 dead, 2 very sick.
C, 2 dead, the third very sick.
Experiment CCCXLV. April 7. Frog eggs, in nearly equal quanti-
ties, in water.
A, under bell full of air.
B, under bell full of air with about 55% of oxygen.
C, under bell full of air with about 65% of oxygen.
D, under bell full of pure oxygen 90% to 95%.
778 Experiments
April 10. The young tadpoles are moving in A and B; some are
free in A.
April 20. All dead in C and D; the tadpoles are alive and free
in A and B.
May 1. Same.
May 4. As neither water nor air was changed, there was begin-
ning to be a little putrefaction in the eggs of A and B; however the
tadpoles are still alive.
May 10. All dead; foul odor in A; a little less in B; no odor of
putrefaction, but a sort of fishy smell in C and D.
Experiment CCCXLVI. April 13. Tadpoles.
A, free air.
B, 5 atmospheres of air.
April 20. All alive.
May 1. A, living; B, dead.
Experiment CCCXLVII. June 26. Carp and larvae of midges in
great number, in water with algae.
A, under bell full of air.
B, under bell full of air with 85% of oxygen.
July 5. The animals in B are less lively than those in A; the
algae look sick.
July 11. All, algae, carp, larvae, dead in B; on the contrary, all
are quite alive in A, the air of which still contains all its oxygen.
Experiment CCCXLVIII. October 4. Larvae of mosquitoes, in
great numbers, in water.
A, under a bell full of ordinary air.
B, under a bell full of air with 52% of oxygen.
C, under a bell full of air with 62% of oxygen.
D, under a bell full of air with 89% of oxygen.
November 8. All the larvae are alive under the different bells;
in A, a great many are transformed, none in B, C, D.
The experiments which have just been reported were made on
vertebrates (fish, tadpoles, and frog eggs) and on invertebrates
(chrysalises, larvae of aquatic insects, little aquatic crustaceans) ;
they gave similar results, and this fact permits one, I think, to de-
duce generalized conclusions.
To me, they seem first to prove that compression to 4 or 5
atmospheres, or, to speak more exactly, oxygen at a tension of 80
and above, has a fatal effect on animals, which is apparent in a few
days on cold-blooded animals, and which, of course, would give
fatal results much more rapidly in warm-blooded animals.
The second conclusion to be drawn from the experiments is
that increase in the oxygen tension above its normal value in ordi-
nary air seemed to bring no advantage, far from it. When any
difference is noticeable, it is in favor of normal air; life persists
Compressed Air; Low Pressures 779
longer there; the development of tadpoles or the larvae of insects
takes place more quickly there.
It seems then to be demonstrated that, for healthy animals, the
ordinary atmospheric pressure provides the best condition of life,
and that an increase, if at all considerable, is more to be feared
than to be desired.
c- £Pf 1y.ct,ion- toxi(i"e de lacide phenique, by MM. Paul Bert and Tolyet. Memoires de la
Societe de biologie, 1870. p. 63-88.
2 Comptes rendus de I'Academie des Sciences, vol. LXIV, p. 622, 1867.
These numbers and those of the following experiments are reduced to 0° and 76 c. pressure
Ihese temperatures, recorded by my thermometer in this experiment and in several others,
are certainly too low, speaking absolutely. But that is of little importance, since only the com-
parison is of interest.
r r, 1 ?hysical researches on the respiration of man. Journal de Vanatomic et de la phvsioloqic
of Robin; l<irst year. p. 524; 1864. '
'Lecons sur la physiologie de la respiration, p. 384.
Chapter V
INFLUENCE OF CHANGES IN BAROMET-
RIC PRESSURE ON PLANT LIFE
It was impossible not to wonder whether barometric pressure
has some direct or indirect effect upon the phenomena of vegeta-
tion.
Everyone knows that as one ascends mountains, the vegetation
is modified. Certain species disappear, others appear which do not
grow in the plains. At great heights, vegetation becomes scanty,
and finally disappears.
These changes in the flora have been carefully studied by
botanists who realize that not only altitude, but also latitude in-
fluence this geographical distribution of a new type. The habitats
of certain species or certain groups vary in altitude according to
the nearness to or the distance from the equator of the mountain
under consideration.
These observations added to the fact that as one ascends the
temperature drops and the other fact that certain plants called
alpine are found at sea level in cold regions have led botanists to
think that the influence of altitude is only the influence of tempera-
ture; so that temperature alone is considered by the classic authors
as the determining factor of the characteristics of the flora of high
altitudes.
There is no proof, however, that diminished pressure in itself
is not a factor in these differences; there is no proof that plants
of the plain would live at a very low barometric pressure, even if
the temperature there satisfied their needs. For plants, in fact,
to the absorption of oxygen is added the daily intake of carbonic
acid, and the effect of pressure upon these gases is not negligible.
On the other hand, when we investigate the depths of the ocean,
we find that plant life ceases at depths which are not very great,
780
Experiments on Plants 781
and that different groups of algae correspond to different levels.
Here, it is not to warmth but to light that changes in the bathy-
metric distribution are usually attributed. The problem is also
complicated by the varying content of free oxygen and carbonic
acid in the depths. But besides these conditions ordinarily con-
sidered, we must not forget the pressure, which may perhaps have
some effect.
We realize that these questions cannot be solved by direct ob-
servation and that they demand the assistance of experimentation.
But we also understand that it is extremely difficult to carry on
such experiments. Plants do not betray by immediate signs, as ani-
mals do, the painful effects of new conditions. They must be kept
under these conditions for a long time to give results. Besides, to
live they must have light. Glass apparatuses capable of sustaining
decreased pressures are difficult and costly to install. It is still
more difficult when we wish to use increased pressure; the small
dimensions, the thickness of the glass, the use of cast-iron pieces
and protecting grillwork make it almost impossible to carry on ex-
periments under satisfactory conditions.
There is, however, one plant phenomenon which lends itself to
experimentation at different pressures, because it takes place in
darkness and requires little room; that is germination. It is to
such experiments that I have devoted myself almost exclusively.
For vegetation properly so-called, I have often used sensitive
plants. This valuable plant was used thus as a reagent, as a kind
of warm-blooded plant, as I once called it.1
In my bibliographical research, made earlier at the end of my
experiments when I was beginning to write the present volume, I
found that an early experimenter had already investigated this
question, and I quote here his account of his attempt to settle it.2
To study the influence of different pressures of the air on vegeta-
tion, or rather on the size and form of plants, at the same time I
sprouted barley in air rarefied by one half, in which the barometer
stood at 14 inches, and in air compressed to double the ordinary
pressure, that is, a pressure of 2 x 28 = 56 inches of mercury. In both
experiments the seeds were sown in heather compost and equally
moistened. Each of the two bells in which the germinating process
took place contained about 320 cubic inches of air, and consequently
the first contained 320 = 160 cubic inches of atmospheric air, and the
2
second 320 x 2 = 640 cubic inches.
The germination of the barley took place at about the same time
in both receivers, and the budding leaflets showed about the same
782 Experiments
shade of green; but at the end of two weeks, there were the follow-
ing differences in the two bells.
In rarefied air the shoots had reached the height of 6 inches, and
in the compressed air 9 to 10 inches. The former were unfolded and
soft; the latter were rolled around the stem and were firm. Finally,
the former were moistened on the surface, and especially towards the
tip, with drops of water, two of which were always opposite each
other, whereas the latter were almost dry, especially on the surface.
This difference surprised me and my classes; I am inclined to believe
that the decrease in the height of plants, as one ascends mountains,
is the result rather of decreased pressure than of decreased tempera-
ture.
We see that really no conclusion can be drawn from this at-
tempt, since the point of comparison, the control, that is, germina-
tion under normal pressure, had been forgotten; a derogation of the
rules of the experimental method which is unfortunately too com-
mon in naturalists.
Subchapter I
PRESSURES LOWER THAN ONE ATMOSPHERE
1. Germination.
Let us begin with experiments made at pressures less than that
of the atmosphere, and first, by experiments on germination.
Experiment CCCXLIX. May 21. Wheat. Sown on damp earth, in
about equal numbers of seeds and covered by bell-jars.
A. Bell of 2.2 liters. Left at normal pressure.
B. Bell of 7.1 liters. Taken to 50 cm. pressure.
C. Bell of 11 liters. Taken to 25 cm. pressure.
May 11. A. The shoots are about 20 cm. high; they are very fine,
very green, very numerous.
B. The shoots are not more than 15 cm. high; they are much less
numerous, but quite green and erect, although rather sickly in ap-
pearance.
C. Not more than 10 cm.; shoots scanty, yellow, drooping.
May 27. A: all up and growing green and thick-set.
B : germination much less advanced.
C: Much less yet.
Several times during the experiment there was a leak and a
vacuum had to be restored; the air therefore was sufficiently renewed.
The earth was well watered and the air saturated with moisture.
Experiment CCCL. June 17. Barley.
Sown in pots full of earth, in equal number of seeds, and placed
immediately:
A. Under a bell of 2.2 liters. Left at normal pressure.
B. Under a bell of 7.1 liters. Taken to 50 cm. pressure.
C. Under a bell of 11 liters. Taken to 25 cm. pressure.
Experiments on Plants 783
June 20. They begin to sprout everywhere.
June 21. Already an evident difference.
June 22. A. The numerous, very green, and very stiff sprouts
measure about 10 cm.
B. Less numerous, less green; about 8 cm.
C. Still less; about 6 cm.
June 23. I cut all the shoots even with the barley seed; there are
76 in A, 36 in B, 25 in C. I put these shoots in the drying-oven and
dry them at 100 degrees for 2 days.
After this time, each shoot in A weighs 8.8 mg.; each shoot in
B, 7.1 mg.; each shoot in C, 6.2 mg.
Experiment CCCLI. June 11. Barley and cress on moistened
earth.
A. Normal pressure. Bell of 1 liter.
B. Air at a pressure of 12 cm. Bell of 6 liters.
C. Air at a pressure of 8 cm. Bell of 8 liters.
The air is renewed every day.
June 16. The shoots in A are very fine and vigorous; nothing
in B or C.
June 20. B: a few radicles and white molds; C: only molds.
I bring B and C to normal pressure; the seeds germinate, those in C
being delayed during the first few days.
I think it unnecessary to report a larger number of experiments;
each of the preceding experiments is really multiple because of the
number of seeds sown together. The following experiments cor-
roborate their results, which are certainly sufficiently clear.
They permit us to draw the indubitable conclusion that the
lower the pressure, the less energetic and rapid is the germination.
I call particular attention to the results of Experiment CCCL, to
which the system of weighing gave especial precision. They show
that at normal pressure each of the barley shoots weighed more
than 8 milligrams, whereas at the pressure of 50 cm., they weighed
only 7, and at 25 cm., only 6.
Furthermore, a much smaller number of seeds germinated at
low pressure than at normal pressure. It is rather difficult to un-
derstand the reason for this inequality, which was very evident in
each experiment; 'in the same experiment, CCCL, in which the
shoots were counted, we found 76 at normal pressure, 36 at 50
cm., and only 25 at 25 cm.
. It is even now, therefore, quite evident that germination must
take place less rapidly and less surely, for seeds like barley, at high
altitudes than on the plain, if we assume that all conditions of
humidity, temperature, and the electrical state of the atmosphere
are similar.
And now there appears the question which we had to settle
784 ' Experiments
when we were speaking of animals. Are the slowness and the
checking of germination due to the low pressure as a physical con-
dition, or should these phenomena be attributed to the lowered
oxygen tension of the air? All that I have said hitherto justified
me in maintaining the truth of the latter hypothesis. Nevertheless
I wished to test it again by double experimental control, although,
it is true, I limited myself to a small number of experiments.
There are two methods to be used, as we have already seen. We
can study germinations at normal barometric pressure, but in
atmospheres with low oxygen content. Evidently, if in this case
we see that germination takes place more quickly in air than in a
medium with less oxygen, the lack of oxygen must be the cause.
We can also compare with germinations in air, at normal pres-
sure, other germinations at low pressures but in superoxygenated
media, so that the real tension of the oxygen is about equal to that
in air under ordinary barometric conditions.
Here first is an experiment made by the first of these methods.
Experiment CCCLII. July 12. Barley sown on wet filter paper;
20 seeds in each plate.
A. Bell of 13 liters; left in air at normal pressure.
B. Bell of 20 liters; I make a vacuum, and admit air in which
the oxygen content has been made very low by burning phosphorus.
The mixture contains 10% of oxygen.
It will be noted that the capacity of the bells varies inversely
with the quantity of oxygen.
July 16. The sprouts in A are stronger than in B.
July 18. The sprouts in A (air) are 12 cm. on the average; those
in B (nitrogen) 10 cm.
July 22. A on the average 21 cm.; B on the average 19 cm.
This experiment shows very clearly that in air with low oxygen
content, even if the total quantity is quite sufficient, germination
takes place less quickly than in ordinary air.
I did not think I should dwell on this sort of experiments, be-
cause the former researches of Senebier, Saussure, Lefebure, etc.,
although they lack precision from the point of view of chemical
analysis of the atmospheric medium, give clear testimony for the
same conclusion.
Here are some experiments made by the second method.
Experiment CCCLIII. October 9, 1872. Barley and cress, sown
on wet paper.
A. Air at normal pressure.
B. Air at a pressure of 16 cm.
Experiments on Plants 785
C. A vacuum is made, then oxygen is admitted until normal
pressure has been restored; then the same operation was repeated;
finally this superoxygenated atmosphere (the sample of which in-
tended for analysis was unfortunately lost) is brought to a pressure
of 16 cm.
October 12, a few seeds begin to germinate in A.
October 14, germination begins in C.
October 16, the sprouts are a little finer in A than in C.
October 19, a few sprouts appear in B; A is still a little ahead
of C.
October 23, in A, the barley is 8 cm. high, the cress 3 cm.; in C,
the barley is 7 cm. high, the cress 3 cm., but its sprouts are not quite
so fine as in A; B has only one barley sprout 6 cm. high at most, and
the cress is only 1.5 cm. high.
Experiment CCCLIV. November 4. Sowing of barley and cress
on wet paper (a score of seeds).
A. Air at normal pressure.
B. Air at a pressure of 15 cm.
C. 71% of oxygen, brought to a pressure of 20 cm., which cor-
responds to 18% at normal pressure.
November 7, a few sprouts appear in A.
November 8, a few in C.
November 11, beginning of germination in B.
November 25, conditions are as follows:
A. The seeds have all sprouted, the sprouts are very green; the
cress is about 2 cm. high, the barley 12 cm.
B. Has risen to 25 cm. pressure. Cress longer, but not so green
as in A. Only 3 sprouts of barley, as long as, but thinner and less
green than in A.
C. Has risen to 40 cm. pressure (consequently is less oxygenated).
The sprouts, very numerous and very fine, are quite like those in A.
These experiments bring us to the same conclusions as the pre-
ceding ones. We see, in fact, that seeds sown in superoxygenated
atmospheres have sprouted as quickly as in air at normal pressure,
in spite of the low barometric pressure to which they were sub-
jected. The low pressure therefore has no effect when the percent-
age of oxygen is sufficient to maintain the real tension of this gas
at a value approximating that in ordinary air at 76 cm.
It is proved then that the delay in germination noted in all the
preceding experiments when the barometric pressure is very low
is due to low oxygen tension. The seeds do not absorb enough, even
though they have at their disposal very great quantities of oxygen
in weight. As in the case of blood corpuscles, absorption of oxygen
by plant cells is in proportion to the outer tension of this gas.
It was interesting to find out the lower limit of pressure at
which germination can take place. The preceding experiments
786 Experiments
show already that it still takes place, though very slowly, at the
pressure of 15 cm., a pressure much lower than that of the atmos-
phere at the summit of the highest mountain, Mount Everest in the
Himalayas.
The following experiments answer this question.
Experiment CCCLV. December 14. Barley (about a dozen seeds)
and cress on wet paper. Bells of 1.5 liters.
A. Air; normal pressure.
B. Air; pressure of 6 cm.; the oxygen tension corresponds to
76 : 6 = 21 : x = 1.6% at normal pressure.
December 17. A. A few seeds of cress have split their coverings.
December 20. A. All the seeds of cress have split their cover-
ings; a few seeds of barley have sent out radicles.
B. Pressure of 7 cm.; nothing has appeared.
January 14. A. The cress seeds have germinated; the barley
shoots are 12 cm. high.
B. Two barley seeds have sprouted; they are 6 cm. high. All
the seeds of B, both cress and barley, sprout when brought to nor-
mal pressure.
Experiment CCCLV I. March 11. 40 seeds of barley and cress sown
on wet filter paper.
A. At normal pressure.
B. In a bell of 7 liters, brought to a pressure of 4 cm.
March 28. A. All sprouted; the barley has sprouts 4, 5, and 6 cm.
high; B, in which the air was changed March 15, 18, 23 and 26, shows
no sign of germination. Pressure is raised to 8 cm.
April 26. The air in B was changed March 31, and April 6, 8,
and 11; nothing has appeared yet except molds.
Sown in the air on wet paper.
May 20. Fine shoots of cress, but the barley has not sprouted.
It is therefore at a pressure of about 7 cm. that germination can
no longer take place. It is interesting to note that this decom-
pression is exactly that at which warm-blooded animals succumb
rapidly, no matter what precautions are taken, and at which cold-
blooded vertebrates cannot live long.
If we look for the percentage of oxygen to which the oxygen
tension at this pressure of 7 cm. corresponds at normal pressure, we
find it by means of the following proportion 20.9: 7 = 76: x = 2.5.
This is very close to the experiments of Lefebure, who showed that
germination of the turnip still takes place, although slowly and in-
completely, when the air contains only 1/32 of oxygen, that is,
3.4%.
Experiments on Plants 787
2. Vegetation.
I made also a few attempts to obtain effects on vegetation prop-
erly so-called.
Experiment CCCLVII. June 15. Barley.
Seeds of barley in the same quantity sown in three similar pots,
full of earth; all left under similar conditions.
June 25. All three sowings have sprouted, but rather unevenly;
in the first, the sprouts measure on the average 14 cm.; in the second,
15 cm.; in the third, 16 to 17.
They are placed under three bells.
A. The least satisfactory sowing; left at normal pressure.
B. The intermediate sowing; taken to a pressure of 50 cm.
C. The best; taken to 25 cm.
June 27. The three sowings have kept their original differences.
July 3. Same result.
Experiment CCCLVIII. July 24. Sensitive plants of the same
sowing; one in each pot, about 10 cm. high.
A. 4 pots under a bell of 3.5 liters at normal pressure.
B. 4 pots under a bell of 7.1 liters; brought to a pressure of 50 cm.
C. 4 pots under a bell of 11 liters; brought to a pressure of
25 cm.
All are set on plates full of well-moistened earth, and are placed
in sufficient light.
The pressure is lowered carefully; the folioles closed when the
pressure had been lowered about 20 cm., then opened again later.
In the evening, C closes its folioles much later than the other two.
July 25. Air has leaked into C; the pressure is about 40 cm. It
is lowered to 25 cm. Some folioles and even some leaves are already
falling; one or two sensitive plants seem dead.
B. Rather sickly.
A. In good shape.
July 26. C. The pressure has risen to about 45 cm.; nevertheless
the sensitive plants are all dead.
B. All sickly, some dead.
A. In very good shape; they are growing.
July 27. B. All dead.
A. In good shape.
Experiment CCCLIX. August 1. Sensitive plants like those of
the preceding experiment. Two in each bell.
A. Taken to a pressure of 60 cm.
B. Taken to a pressure of 50 cm.
C. Taken to a pressure of 25 cm.
August 3. A few folioles and leaves fall in C.
August 6. 3 o'clock. A. Folioles sensitive and open; B. Half-
closed or not very sensitive; C. Completely closed.
August 7. Brought back to normal pressure.
All are sensitive; C. Much less than the others; C does not close
well in the evening.
August 9. A. In good shape; very sensitive; B. Not very sensitive;
sickly; yellowish; C. Leaves are falling; dying.
788 Experiments
It is quite certain then that under the influence of low baro-
metric pressures, sensitive plants quickly lose their sensitivity and
die. Now we should learn the cause of this death. Should we
attribute it, as we have been accustomed, so to speak, to do hitherto,
to low oxygen tension? Should we merely blame the expansion of
the gases within the plant, an expansion which is due to the de-
compression and which would be great enough to affect such a deli-
cate plant fatally?
The following experiment answers this question.
Experiment CCCLX. July 25. Two pots, each containing 3 young
sensitive plants.
A. Taken to a pressure of 25 cm.
B. Pressure lowered 50 cm., and oxygen admitted then pressure
brought to 25 cm. The oxygen tension in this bell corresponds about
to that of the air at normal pressure.
July 26. A. Sick.
July 27. A. Dead; B. In good health.
Here again the too low oxygen tension killed the sensitive
plants subjected to low pressure.
Finally here is an experiment which, although it was made on
an almost microscopic plant, has a certain interest.
Experiment CCCLXI. April 8. Fragments of frog eggs, with a
little of Priestley's "green matter."
A. Flask at normal pressure.
B. Flask at a pressure of 25 cm.
April 25. Green matter abundant in A; nothing in B.
So a lowering of the pressure is harmful to vegetation as it is
to germination; it kills plants at the same degree at which it kills
cold-blooded animals, and completely checks the life of seeds, with-
out, however, killing them entirely.
The unity of the phenomena of respiration in the two kingdoms
is emphasized here very clearly.
Subchapter II
PRESSURES ABOVE ONE ATMOSPHERE
1. Germination.
Let us now take up experiments made under increased pressure;
and first, germination. I have always made my sowings on wet
paper, because previous experiments have shown me that the pres-
ence of earth complicates the results.
Experiments on Plants 789
Experiment CCCLXII. July 7. Sowings of barley on wet filter
paper.
A. Receiver of 1 liter, taken to 1 and % atmospheres.
B. Similar receiver; normal pressure; well corked.
July 9. B. Begins to sprout; A. Nothing.
July 10. B. The sprouts are about 2 cm. high; they begin to ap-
pear in A.
The air is renewed every day.
July 13. B. Sprouts about 12 cm. high; A. Only 8 to 10 cm. high.
Experiment stopped.
Experiment CCCLXIH. July 13. Sowings of barley on wet filter
paper. 20 seeds in each sowing.
A. Cylindrical receiver holding 650 cc, taken to 5 atmospheres.
Air changed every day.
B. Test glass of about the same dimension; left at normal pressure;
well corked.
July 16. Germination begins in B.
July 18. In B, the sprouts are about 7 cm. high; germination is
beginning in A.
July 20. B. 13 cm.; A. 3 to 5 cm.
July 26. B. 18 cm.; A. 3 to 5 cm.
Decompression made, the different seeds removed carefully and
placed on wet earth.
A. Grows rapidly and nearly overtakes B.
Experiment CCCLXIV. July 31. Sowings of barley on wet paper.
A. Cylindrical receiver taken to 10 atmospheres.
B. Test glass of same volume; normal pressure; well corked.
August 3. Germination begins in B.
I decompress A; but on recharging it, I cannot get it above 7
atmospheres.
August 5. The sprouts in B are 5 to 6 cm. high; in A, only a few
radicles have sprouted.
August 7. 13 cm. in B; in A, only a few radicles.
I stop the experiment; the air in A, when analyzed, contains no
carbonic acid.
A. Sown on wet paper; has not begun to germinate August 10.
Experiment CCCLXV. March 1. Sowings of 30 barley seeds.
A. In the cylindrical reservoir, ordinary air, pressure of 2%
atmospheres.
B. Closed test glass; normal pressure.
March 4. Air changed.
March 8. Shoots greener and longer in B than in A. Air changed.
March 10. A. 9 seeds not germinated; 11 with radicles only; 10
with pale shoots 2 cm. long.
B. 11 seeds not germinated; 5 with radicles only; 11 with fine
green shoots 4 cm. long.
790 Experiments
Experiment CCCLXVI. March 30. Sowings of 20 barley, seeds on
the same quantity of paper wet with 10 cc. of water.
A. Small Seltzer water receiver; 2 atmospheres of air changed
every day, sometimes twice a day.
B. Similar receiver, corked at normal pressure.
April 3. Radicles appearing in both.
April 7. A. Is a little slow, in comparison with B.
Experiment CCCLXVII. April 16. Sowings of 20 barley seeds.
Same quantity of paper and water.
A. Small Seltzer water receiver without a wire jacket; taken to
2V2 atmospheres. As this receiver leaks a little, I recharge it at least
twice a day, sometimes to 3 atmospheres; this gives sufficient ven-
tilation.
B. Similar receiver, with a jacket, corked; normal pressure; air
changed every day.
April 19. Radicles appear in A and B.
April 24. No very clear difference; the shoots are about 6 cm.
high, but they are a little paler in A than in B.
April 28. The two sowings are almost identical, measuring 10 to
12 cm. The shoots in A are not as green as those in B, and yet they
receive considerably more light.
Experiment CCCLXVIII. April 28. Sowings of 20 barley seeds
and radish seeds.
A. In the cylindrical receiver, at 10 atmospheres of air; the
air is changed every day, morning and evening.
B. In a vessel poorly corked; normal pressure.
May 7. A. No apparent development; B. The radish sprouts are
1.5 cm. high; the barley sprouts 3 cm. high.
May 12. A. A very few radicles of radish and barley.
B. The radish shoots are 3 to 5 cm. high; the barley, 5 to 8 cm.
I make the decompression and sow A on wet paper; the radishes
begin to sprout May 16; the barley molds.
Experiment CCCLXIX. June 11. Sowed 20 barley seeds and 20
cress seeds.
A. In the cylindrical receiver, at 5 atmospheres of air; air changed
twice a day.
B. In a closed test glass; normal pressure.
June 13. A few radicles of barley and cress in A and B.
June 16. A. The cress has germinated; the barley has not sprouted.
B. Cress finer than in A; barley measuring 1 to 2 cm.
June 18. A. The cress sprouts are 1.5 cm. to 2.5 cm. high; the
leaves are not yet unfolded and do not smell of cress; the barley
sprouts, to the number of 16, are beginning to leave their cover, and
are 1.5 cm. to 4 cm. high.
B. The cress sprouts, 3 cm., very green, spread out in a rosette,
smelling very strong of cress; 20 barley shoots from 8 to 9 cm., some
as high as 12 cm.
Experiments on Plants 791
Experiment CCCLXX. June 19. Barley and cress on wet paper.
A. Under a bell; normal pressure.
B. 6 atmospheres of air.
Air changed every day.
June 22. A. Cress germinated; little stalks of barley started.
B. Cress hardly shows any sign; a few barley radicles to be seen.
June 29. A. Cress, 3 cm., very green and smelling strong; barley
from 12 to 20 cm.
B. Cress, 2 cm., very green and smelling strong; barley, stalks
1.5 cm. high.
Experiment CCCLXXI. August 17. Sowings on wet paper of
seeds of marvel-of-Peru, castor beans, and melon, which were
decorticated after being kept for two days in water.
A. Cylindrical apparatus at 2 atmospheres of air.
B. Open vessel.
August 18. 9 o'clock in the morning; in A and in B, some mar-
vels-of-Peru have germinated.
I raise A to 6 atmospheres, and change the air every day.
August 23. A. Same condition.
B. The radicles of the melon and castor bean seeds are appear-
ing.
August 26. A. Nothing has sprouted.
B. The marvels-of-Peru are 2 to 3 cm. high; the melon and cas-
tor bean seeds have sent out all their roots.
B continues to sprout in the open air, whereas nothing sprouts
in A.
These experiments show very clearly that, beginning with a cer-
tain pressure, germination is delayed, and that at a higher pressure
it does not take place. Furthermore, certain seeds die then and
cannot develop when brought back to normal pressure.
But before studying these results in detail, we must once more
settle the question which we have encountered several times, and
find out whether this fatal effect is due to the pressure itself or to
the increased chemical tension of the oxygen.
And here, once more we have the different methods which we
are accustomed to using: 1). to make the compression with air with
low oxygen content, so that the tension of this gas is equivalent to
that of the oxygen in the air at normal pressure; 2). to make ex-
periments at normal pressure with air which has a greater oxygen
content than ordinary air; 3). to use both low pressure and air
which is superoxygenated, so that we obtain high tension with
low pressure.
792 Experiments
A. High Pressures with Air of Low Oxygen Content.
Experiment CCCLXXII. July 13. Sowings of barley on wet paper.
A. Receiver at normal pressure, well corked.
B. Similar; taken to 4 atmospheres, 3 of which are of air with
very high nitrogen content.
July 14. Raised to only 2 atmospheres. Renewal has been made
and is made every day with air of very high nitrogen content.
July 16. 3 atmospheres. Nothing in either A or B.
July 17. A little germination in both.
July 19. A. Sprouts a little stronger than those in B.
July 22. Same.
The air in B. contains 1.7% of carbonic acid and 11.9% of oxygen.
The oxygen tension at the end was therefore 13.6 x 3 = 40.8.
Experiment CCCLXXIH. November 4. Barley and cress on wet
paper.
A. Glass receiver at normal pressure.
B. Cylindrical apparatus, at 8 atmospheres of air with low oxygen
content; the mixture contains 5.7% of oxygen, the tension of which
5.7 x 8 = 45.6 corresponds to about 2 atmospheres of air.
November 7. A, a few seeds have germinated.
November 8. A, a few more; B, nothing. The apparatus leaks, the
pressure has fallen to 6 atmospheres; it is raised to 8 with the same air.
November 9. A few barley seeds are germinating in B; in A, the
sprouts are already fine.
November 11. Same condition; decompression is made, and the
seeds from B are sowed on wet earth. The gas in the apparatus con-
tains CO, 3.2; O, 1.6; the CO tension is therefore 3.2 x 8 = 25.6.
November 20. The cress is 3 cm., the barley 5 or 6.
Experiment CCCLXXIV. August 2. Sowings of barley and cress.
A. Cylindrical apparatus taken to 10 atmospheres of an air which
contains 9.8% of oxygen; the tension of this gas is therefore 98, cor-
responding to about 5 atmospheres of air.
B. Test glass, normal pressure.
August 3. I bring A down to 7 atmospheres; the oxygen tension
is only 7 x 9.8 = 68.6, or a little more than 3 atmospheres of air.
August 4. The cress and barley have sprouted in both, but A is
evidently more delayed than B.
It is already plain from these experiments that the oxygen is
to blame. In fact, in Experiment CCCLXXII, if we had used ordi-
nary air, germination would have been considerably delayed,
whereas it was hardly delayed at all; in the other two experiments,
it would have been completely stopped by pressures of 8 and 10
atmospheres, whereas there was only a delay explainable by the
oxygen tension, which was already equivalent to 2 atmospheres
(Exp. CCCLXXIH) or 3 atmospheres (Exp. CCCLXXIV) .
In Experiment CCCLXXIH a new element, the high tension of
Experiments on Plants 793
carbonic acid, was introduced and complicated the results. That
is why I did not make more experiments by this method, in which
it is quite difficult to renew sufficiently an air with low oxygen
content.
B. Normal Pressure: Superoxygenated Air.
I now come to the more numerous and much more conclusive
experiments conducted by the second method.
Experiment CCCLXXV. July 12. Barley sown on wet paper; 20
seeds.
A. Bell of 7 liters; air containing 65% of oxygen, which cor-
responds to 3 atmospheres of air.
B. Bell of 13 liters; ordinary air.
July 18. A, the shoots are 8 cm. high; those in B, 12 cm.
July 22. A, an average of 15 cm.; B, an average of 21 cm.
Experiment CCCLXXV I: November 4. Sowings of barley and
cress on wet paper.
A. Air with 79% of oxygen, equivalent to about 4 atmospheres
of air.
B. Ordinary air.
November 7. A few seeds germinating in B.
November 9. A few seeds germinating in A.
November 25. A. Only two barley seeds have sprouted, and
measure 4 cm.; the cress is about 2 cm.; none of the shoots are very
green.
B. All the seeds have germinated and are very green; the cress
is about 2 cm. high, the barley 12 cm.
Experiment CCCLXXVII. December 7. Twenty seeds of barley
and cress on wet paper. Bells of 2 to 3 liters.
A, in air with 65% of oxygen.
B, in air with 40% of oxygen.
C, in air with 31% of oxygen.
D, in ordinary air.
December 17. The cress has sprouted in all quite equally. The
barley is sending out radicles in all.
January 1. A. The barley shoots are 9 cm. high, the stalks are
half open, slender, not many; the cress is 2 cm. high; not all of the
seeds have germinated.
B. Barley 12 cm., stalks green; cress 2 cm.
C. Barley 13 cm., stalks slender, but closed; cress 3 cm.
D. Barley 10 cm., stalks thick, unfolded, green; cress 2 cm., thick,
very green.
January 14. A. Barley 11 cm., stalks faded, slender, scanty;
cress 2 cm.
B. Barley 14 cm., stalks green, unfolded; cress. 3 cm.
C. Barley 16 cm., stalks long, slender, folded; cress 4 cm.
D. Barley 13 cm., leaves open, very green; cress 3 cm.
794 Experiments
January 20. A. Barley 11 cm., all yellow, dying; B and C, barley
20 cm., stalks yellowish; D, 14 cm., very green.
So B and C sent out stalks longer than D, but not as healthy;
A is in very bad condition.
Experiment CCCLXXVIII. March 11. 40 seeds of barley and
of cress are sown on wet filter paper, and placed:
A. In a bell of 2.5 liters, full of air at normal pressure.
B. Bell of 2.25 liters; normal pressure; air containing 30.2% of
oxygen, which corresponds to about W% atmospheres of air.
C. Bell of 2.6 liters; normal pressure; air containing 43% of
oxygen, or a little more than 2 atmospheres of air.
D. Bell of 2.5 liters; normal pressure; air with 58.3% of oxygen,
or 2% atmospheres of air.
March 29. Experiment stopped; the barley and the cress have
sprouted in all four bells; in A and B the sprouts are a little greener
and from 1.5 to 2 cm. longer than in C and D. Besides, the air in B
contains only 17.5% of oxygen, with 13.4% of carbonic acid; the
air in C contains 28.2% of oxygen and 12.3% of C02; that in D, 44.8%
of oxygen and 11.2% of CO,; the air in A has been renewed.
Experiment CCCLXXIX. May 6. Sowings of barley.
A. Air with 94% of oxygen, that is, 4M> atmospheres of air.
B. Ordinary air.
May 13. The barley has sprouted in both; A seems a little better
and is greener.
But on the following days, B has the advantage, and on May 20,
the sprouts in A are only 2 to 3 cm. high, whereas those in B are
8 to 9 cm. high.
However, the analysis of the air in B discloses no more oxygen,
and there is 25.4% of carbonic acid; in A, there is 19.9% of C02, and
only 71.6% of oxygen.
The average oxygen tension then was about 4 atmospheres of air.
C. Low Pressures : Superoxygenated Air.
Experiment CCCLXXX. November 4. Sowings of barley and
cress on wet paper.
A. At a pressure of 3 atmospheres of an air containing 86.9%
of oxygen. The tension of this gas is then 260, corresponding to
about 12 Vz atmospheres of air.
B. Normal pressure, ordinary air.
November 7. Nothing in A; a few sprouts in B.
November 11. Nothing in A; all have germinated in B. The air
in A still contains 86.2% of oxygen, with 0.7% of carbonic acid.
The seeds in A are sown on wet earth. November 20, the cress
begins to sprout, but the barley is dead.
Experiment CCCLXXXI. May 31. Sowings of barley seeds on
wet paper.
A. 5 gm. in the cylindrical reservoir at 3 and Vs atmospheres of
an air containing 54% of oxygen; the tension corresponds to 180, that
is, about 9 atmospheres of air.
Experiments on Plants 795
B. 8 gm., normal pressure, ordinary air, bell of 1840 cc.
June 3. No germination. Air changed in B. and oxygen changed
in A. After this, the air in A contains 46.2% of oxygen, the pressure
is dropped to 3 atmospheres; the tension then is 138, that is, a little
less than 7 atmospheres.
June 7. A. A very few radicles; the pressure has fallen fo 2
atmospheres; the air contains 2% of CO, and 41.2% of oxygen.
B. The shoots are 3 to 5 cm. high and are very green. The air
contains 8% of CO, and 11.2% of oxygen.
Assuming for A an average pressure of 2 V% atmospheres, we find
that in 4 days, the seeds in A have consumed, per 10 gm., 136 cc. of
oxygen, and those in B 225 cc.
The seeds in A are sown on wet earth and develop.
Table XVII summarizes the principal results of the experiments
above. They are arranged by the increasing order of oxygen ten-
sions expressed in atmospheres.
The different methods used agree in showing that even a slight
increase in oxygen tension acts unfavorably on germination; be-
ginning with two atmospheres or 40% of oxygen, it is manifestly
delayed.
At 5 atmospheres, which corresponds to pure oxygen, the delay
in germination is very great.
Above 7 atmospheres, the seeds merely send out a few radicles,
no stalk appearing.
Finally, at about 10 atmospheres, the barley seeds, when brought
back to normal pressure, are dead and do not germinate, whereas
cress seeds are resistant and sprout, although somewhat slowly
(Exp. CCCLXXX) .
Now cress seeds have thin, dry cotyledons and contain no albu-
men. I wondered whether the death of the barley seeds did not
result from some chemical change in their considerable albumen
content.
My experiments on fermentation, which will be reported in this
chapter, have convinced me of the truth of this hypothesis. Besides,
we see by Experiment CCCLXXI that fleshy seeds like those of the
castor bean and melon were much more affected by the pressure
than those of the marvel-of-Peru, which are more like cress seeds.
In conclusion, I call attention to the fact that to obtain conclu-
sive results, the seeds must be wet. Otherwise, the oxygen, in
spite of the high tension, would not kill them. Example:
Experiment CCCLXXXII. July 19. Dry wheat placed in a flask;
in another, wheat previously moistened, which however is not covered
with water,
796
Experiments
The two flasks are subjected to 15 atmospheres of an air containing
70% of oxygen.
July 31. Decompression and sowing.
The dry wheat sprouts very well; the other rots in the ground
without sprouting.
TABLE XVII
Experiment
Number
e-a
PQ a
o3g£
>.ja in
3'££
ra c <"
QS.
Species
Tested
Comparison with
normal pressure
CCCLXXVII1
CCCLXXVII
CCCLXII
CCCLXXVIII
CCCLXXVII
CCCLXXII
CCCLXVI
CCCLXXVIII
CCCLXVII
CCCLXV
CCCLXXV
CCCLXXVII
CCCLXXIV
CCCLXXVI
CCCLXXIX
CCCLXIX
CCCLXIII
CCCLXXX
CCCLXXI
CCCLXIV
CCCLXXXI
CCCLXVIII
H
U
I 1%
U
U
13
2
II
I 1V2
I iy2
1 1% l 6
|2 |18
|2 |43
12 I 9
12 I 8
I 2V2 I 18
2V2 I 21/2 I 12
2% I 2% I 10 I
3V4
4
4%
5
5
16 |S
101
43|
I
21
HI
I
7
HO
[13
10
CCCLXX
7
3
7
7
8 1
7 1
10
10
14|
3
12V2
7 1
Barley and cress
Barley and cress
Barley
id.
Barley and cress
Barley
id.
id.
id.
id.
id.
Barley and cress
id.
Barley
Cress
Barley
Barley and cress
Barley
Barley and cress
I Four o'clocks
I
-j Castor bean
[ Melon
Barley
id.
id.
Cress
Barley
Cress
As well as in air
Longer; but less healthy
Somewhat backward
Slightly delayed
Longer, but less healthy
Somewhat backward
id.
id.
A little paler
Evident delay
Delayed
Delayed and very un-
healthy
Delayed
Only a few seeds
sprouted
Sprout, not very green
Very much delayed
Very much delayed
Very much delayed,
but sprouts wefl in
open aii-
Very much delayed,
especially the barley
Germinate, but do not
grow, even in open air
Does not germinate,
even in open air
A few rootlets
A few rootlets; sprouts
in open air
Does not germinate,
even in open air
Germinates after being
taken into open air
Nothing; dead.
Nothing sprouts at nor-
mal pressure.
Experiments on Plants 797
2. Vegetation.
Experiments on vegetation are very hard to perform, as is
easily understood, because of the small size of the glass receivers
and their lack of transparency. Yet here are a few which are suf-
ficiently conclusive.
Experiment CCCLXXXIII. April 28. Barley sprouted 10 to 12 cm.
high in the large Seltzer water receivers (2 liters).
A, which is in the receiver with a wire jacket, is closed and left
at normal pressure.
B, in a receiver without a jacket, which lets more light through,
is taken to 3 superoxygenated atmospheres, changed tv/ice a day.
May 7. In A, the sprouts have more than doubled their length; B
has not changed: left in open air, the stalks turn yellow and die.
Experiment CCCLXXXIV. July 25. Little sensitive plants 6 to 8
cm. high, healthy, in a pot.
A. Placed, in the pot, in a receiver of 1 liter, with wire mesh
jacket; left at normal pressure, well corked.
B. Another pot in a similar receiver, without the wire mesh
jacket, and consequently under better lighting conditions. Carried to
6 atmospheres of air.
By evening B has lost sensitivity.
July 26. The leaves in B are falling.
July 27. B completely dead; A healthy.
Experiment CCCLXXXV. August 1. Sensitive plants like those in
the preceding experiment. Same receivers.
A. At 3 atmospheres.
B. Under normal pressure.
August 5. Both sensitive and healthy.
Experiment CCCLXXXVI. July 25. Small sensitive plants, quite
sensitive.
A. Cylindrical apparatus at 4 atmospheres with 80% of oxygen;
tension 320, equivalent to nearly 16 atmospheres of air.
B. Normal pressure, air.
July 27. A, dead; B quite sensitive.
So sensitive plants die quickly at 6 atmospheres of air, and it
is more than probable that the other green plants would die at the
same pressure, although much less rapidly. Plants, therefore, seem
to dread excessive oxygen tension still more than animals, even
warm-blooded animals.
798 Experiments
Subchapter III
SUMMARY
The experiments included in the present chapter prove in sum-
mary that at pressures above or below one atmosphere, the germi-
nation and the vegetation of green plants are delayed, even ar-
rested. Just as for animals, this fatal effect is due not to the pres-
sure itself, but to the oxygen tension, either too weak, whence there
results a kind of asphyxia, or too strong, killing the seeds or the
plants.
In the third part of this book, we shall draw from these data
the conclusions which they permit in regard to the geographical
distribution of plants and the appearance of plant life on the sur-
face of the earth.
1 P. Bert. Sur les mouvements de la sensitive, Second memoir. Societe des sciences
physiques et naturelles de Bordeaux, Vol. VIII, p. 1-58, 1870.
2 Dobereiner, Experiences sur la germination dans fair condense ou rarefie. Biblioth. univ.
de Geneve, Vol. XXII, p. 121, 1823.
Chapter VI
EFFECT OF CHANGES IN BAROMETRIC
PRESSURE ON FERMENTS, POISONS,
VIRUSES AND ANTOMICAL ELEMENTS
The admirable researches of M. Pasteur have shown that the
phenomena known by the name of fermentations belong to two
very distinct categories. Some are related to the development of
microscopic living beings, vegetable or animal, such as alcoholic,
acetic, and butyric fermentations and putrefaction. Others are
caused by the action, still not understood, of substances produced
by living beings, but soluble in water, and keeping their power
after being isolated from the liquids in which they existed, and
even after being dried; such is the transformation of starch into
glucose under the influence of animal or vegetable diastase; or the
formation of the essence of bitter almonds by synaptase acting on
the amygdalin, etc.
It was quite natural to inquire whether changes in the baro-
metric pressure (we can now say in the tension of the ambient,
oxygen) would have any appreciable effect on these phenomena.
In the first place, for true fermentations, it was simply a question
of whether an agent which according to its concentrations is both
so necessary and so dangerous as oxygen, the lack of which ends
life and the excess of which kills animals and plants which are
visible to the naked eye and are of a rather complex anatomical
organization, would have no effect upon microscopic beings, re-
duced to cellular structure. As for the false fermentations, the
zymotic fermentations, since they surely play a very great part in
the chemical phenomena of metabolism in all living beings, it was
interesting to find out whether oxygen tension could act upon them.
Poisons and viruses, which resemble the ferments of these two
classes from so many points of view, also deserved to be tested.
799
800 Experiments
And finally, after studying these varieties of free anatomical ele-
ments, I thought I should investigate the effect of changes in the
oxygen tension upon the different anatomical elements, which in
combination constitute a living being.
The strange effects of increased pressure were to engage my
attention particularly. Nevertheless I made a few experiments
with rarefied air; but I combined my report of them with that of
the others, since generally they were made simultaneously.
Finally I should say that I employed in turn according to the
best interest of the experiments either ordinary air compressed, or
superoxygenated air compressed, or superoxygenated air at normal
pressure. I consider that all my previous researches have suffi-
ciently demonstrated this truth, that the effect of the compression
is nothing but the effect of oxygen at high tension. Furthermore,
for the questions discussed in this chapter, the experiments con-
stitute a control which is proof in itself.
Subchapter I
FERMENTATIONS BY ORGANISMS
1. Putrefaction.
As a type and as a subject of study I selected the fermentations
of putrefaction in particular. Certainly, from the standpoint of
chemistry, the phenomena presented by putrefaction are extremely
complex and hard to follow. But its consistency, the facility with
which it is produced, and its characteristic outward signs which
are easy to observe seemed to me very advantageous for my pur-
pose. And so I shall begin by reporting the principal experiments
which I performed on this important subject.
I shall first take up the putrefaction of meat.
A. Meat.
Experiment CCCLXXXVI. July 21. Temperature 22°. Muscles of
a dog killed some hours before. 100 gm., cut in pieces, are placed:
A, in a flask of 2 liters, at normal pressure;
B, in a flask of 4.250 liters, at a pressure of 38 cm.;
C, in the Seltzer water receiver, containing 1050 cc, in which I
compress to 5% atmospheres a superoxygenated air containing 75.7%
of oxygen.
Oxygen tension: 75.7 x 5.5 = 416, equivalent to about 20.8 atmos-
pheres.
Fermentations by Organisms ' 801
July 25. A. The manometric tube attached indicates about 1 cm.
(mercury) excess pressure. The meat is evidently very rotten. The
air of the flask is horribly foul; it contains 38% of carbonic acid, but
no trace of oxygen. Therefore 410 cc. of oxygen were consumed and
760 cc. of carbonic acid produced.
B. The pressure has dropped 1 cm. at the most; the meat looks
rather rosy. The air of the flask is a little less foul than that in A;
it contains 30.9% of C02, but no trace of oxygen. Therefore 440 cc.
of oxygen were consumed and 649 cc. of C02 were produced.
C. Pressure maintained well. The meat is amber colored. The air
of the receiver has no odor; it contains 7.2% of C02 and 69% of oxygen.
Therefore about 357 cc. of oxygen were consumed and 396 cc. of CO?
were produced.
Experiment CCCLXXXVII. July 27. 7 o'clock in the evening.
Temperature 23°. A small dog having died the evening before, its hind
feet, weighing 95 gm., were placed:
A, under a bell of 3.200 liters, full of air at normal pressure; the
bell being tightly closed.
B, in the Seltzer water apparatus (1050 cc), with 4 superoxygen-
ated atmospheres.
July 28. At 5 o'clock, the air is changed in A and in B, which is
kept at 7 atmospheres.
July 29. 2 o'clock. A. The air, which has no odor, contains: 02 17.1;
CO, 1.8. The meat is reddish.
B. The air has no odor, and contains: 02 65.5; C02 0.8. The oxygen
tension therefore was at the beginning about 66 x 7 = 462, equivalent
to 23 atmospheres of air. The meat is yellowish. I change the pressure
to 6V4 atmospheres.
July 31. 5 o'clock in the evening. Temperature 23°. A. The air
smells very bad; it contains: 02 3.8; CO., 17.2; therefore, since July 29,
534 cc. of oxygen has been consumed and 117 cc. of C02 has been
formed.
B. No odor. 32 cc. of oxygen has been consumed, and 50 cc. of C02
formed.
A is taken out and the air changed, with the same bell; the meat
has a terrible odor; the hairs and the epidermis are coming off.
B is taken to 6 atmospheres.
August 3. 2 o'clock. Temperature 21°. A. Air has a disgusting
stench; covered with mold. The air contains no trace of oxygen, but
23.9 of CO.; since July 31, 651 cc. of oxygen has been consumed and
741 cc. of CO.. has been formed.
B. No odor, no mold. The air contains 59.2 of oxygen and 5.2 of
C02. Therefore 348 cc. of oxygen has been consumed, and 212 cc. of
CO, formed.
B is taken out and put on a plate in the laboratory. The next day
it begins to smell bad; on August 7, mold appears on it.
Experiment CCCLXXXVIII. November 14. Temperature 14°.
A. I place in the cylindrical glass apparatus two mutton cutlets,
and subject them to a pressure of 11 atmospheres, with air containing
802 • Experiments
79.9% of oxygen. The tension of this gas is therefore 879, correspond-
ing to about 44 atmospheres of air.
B. Another cutlet is hung up in a huge closed bell.
November 19. B is foul.
A looks good. The manometer has fallen to 7 atmospheres. The
air, which has absolutely no odor, contains 78.4% of oxygen and not
a trace of carbonic acid.
I raise the pressure again to 11 atmospheres with new oxygen.
November 21. Still no bad odor in A; appearance good.
I take a fresh cutlet C, and hang it in a bell absolutely full of
water. I then admit to this bell a certain quantity of compressed air
coming from A; some water remains at the bottom of the bell. A
then drops to 6.5 atmospheres.
November 24. No odor in A. A very slight leak is permitted so
that on November 25 the pressure is normal; the cutlets have a yel-
lowish color.
B is then in complete putrefaction. C is yellowish, and the water
has risen in its bell.
December 13. I open the apparatus and end the experiment.
A. Meat, rose colored, a little acid; faint odor of pickle. I have
the cutlets broiled; they have an insipid, but not repulsive taste.
B had to be disposed of December 10, reduced to absolute decay.
C. Meat flabby, pink, a little acid; disagreeable odor, not that of
ordinary putrefaction.
Experiment CCCLXXXIX. November 22.
A. In the Seltzer water receiver (1050 cc.) are placed two cutlets,
which are taken to 8 superoxygenated atmospheres.
B. Another cutlet is placed in oxygen under a bell.
C. A third, under a bell, in air.
November 24. A has dropped to 2 atmospheres; I take it back to
8 atmospheres; the meat is a dull red.
B is bright red.
C is of ordinary color.
December 1. A has no bad odor; normal consistency; alkaline
reaction; yellowish appearance.
B. Bad odor; alkaline reaction.
C. Absolutely foul odor; flesh diffluent; acid reaction; darkens
paper with lead acetate.
Experiment CCCXC. December 11.
Under two bells inverted over water, one of which, A, contains
air, the other, B, oxygen, fragments of muscle are hung.
January 8. The air is foul in both bells; A shows a great deal of
mold; B, only a little.
Experiment CCCXCI. December 19. Three pieces of lean meat are
cut as nearly alike in iorm as possible.
A. One, weighing 45 gm., is hung under a closed bell, of 11.5
liters, full of ordinary air.
B. The second, weighing 40 gm., is hung in a bell of 3.2 liters,
which contains air with 90% oxygen.
Fermentations by Organisms 803
C. The third, weighing 35 gm., is placed in the cylindrical glass
apparatus, and subjected to the pressure of 10 atmospheres of air con-
taining 88% of oxygen; the oxygen tension therefore is 880, corre-
sponding to 44 atmospheres of air.
December 26. Samples of air are taken from the three bells with-
out the air being renewed.
A. The meat looks bad; the lower part is evidently putrefied.
The air has an insipid odor, slightly gamy. The air contains: O, 12.2;
C02 6.4.
B. The meat has about the same appearance. Insipid odor. The
air contains: 02 70; CO, 12.9.
C. The meat looks good but rather brown. No odor. The composi-
tion of the air has not changed.
January 8. Samples of air are taken again, and the experiment
is stopped.
A. Meat very acid, with a horrible odor; softened. The air con-
tains 7% of oxygen and 12.3% of CO..
B. Meat very acid; odor very bad, but not as strong as A. The
air contains 40% of oxygen and 38.2% of CO..
C. Meat a little acid, grayish, firm, with a slight sourish odor,
which is not disagreeable. Cooked, it is insipid, but without a bad
taste.
The composition of the air has not changed. If we try to deter-
mine, in these two periods, the quantity of oxygen which has been
consumed, and the quantity of CO. which has been produced by the
meat placed in these different conditions, we get the following results,
in which all are reduced to an equal weight, 100 gm. of meat.
From December 19 to 26:
A (ordinary air, normal pressure) has consumed 2.2 liters of
oxygen and produced 1.6 liters of C02.
B (air with 90% of oxygen, normal pressure) has consumed 1.7
liters of oxygen and produced 1.2 liters of C02.
C (air with 88% of oxygen, 10 atmospheres) has consumed 0 liters
of oxygen and produced 0 liters of CO..
From December 26 to January 8:
A (air with 12.2% of oxygen) consumed 1.3 liters of oxygen and
produced 1.4 liters of C02.
B (air with 70% of oxygen) has consumed 2.6 liters of oxygen
and produced 2 liters Of C02.
C (air with 88% of oxygen, 10 atmospheres) has consumed 0
liters of oxygen and produced 0 liters of CO,.
I call particular attention to this experiment. It shows that in
twenty days the meat in compressed oxygen consumed no oxygen
and produced no carbonic acid; it showed no sign of putrefaction.
We see, furthermore, that the meat consumed less oxygen in
air with 90% of oxygen than in air with 21%, but more in air with
70% than in air with 12.
804 Experiments
Experiment CCCXCII. January 17. Pieces of meat equal in weight
and similar in form.
A. Placed in a bell of 15.5 liters, in which the pressure is lowered
to a half-atmosphere.
B. Bell of 7.1 liters; ordinary air, at normal pressure.
C. Bell of 2.6 liters; air at normal pressure, containing 59% of
oxygen.
D. Bell of 3.2 liters; air at normal pressure, containing 59.8% of
oxygen.
All these bells are hermetically closed, with hydraulic seal.
January 23. The meat least altered in appearance is that in A;
those most altered are in C and D. Air samples are taken:
B contains 13.5% of oxygen and 7.2% of carbonic acid.
A contains 16.4% of oxygen and 5.3% of carbonis acid.
C contains 25.2% of oxygen and 19.1% of carbonic acid.
D contains 36.0% of oxygen and 17.3% of carbonic acid.
We can calculate easily by means of these data that in 6 days:
A (ordinary air, at V2 atmosphere) had consumed 343 cc. of oxy-
gen and formed 418 of CO2.
B (ordinary air, at 1 atmosphere) had consumed 524 cc. of oxygen
and formed 514 of CO».
C (superoxygenated air, corresponding to 2x/2 atmospheres) had
consumed 642 cc. of oxygen and formed 496 of C02.
D (superoxygenated air, corresponding to 3 atmospheres) had
consumed 761 cc. of oxygen and formed 556 of CO2.
The consumption of oxygen then consistently increased from V2
atmosphere to 3 atmospheres.
Experiment CCCXCIH. January 14. Pieces of beef are placed in
two small flasks (A and A'), through the stoppers of which a capil-
lary tube passes; they are then placed in the cylindrical apparatus
under a pressure of 10 superoxygenated atmospheres.
January 27. Decompression; the meat, slightly brownish, does not
seem spoiled. The capillary tubes are rapidly sealed with boiling wax,
and the two flasks are inverted in vessels full of water. Two pieces of
meat are placed in the same way beside them (B and B').
February 10. B and B' are evidently rotten, and smell bad through
the corks.
A has admitted a little water; since then, the meat has become
red again; the water is slightly bloody and covered with mold. A', on
the contrary, is very firm, very wholesome, amber in color.
March 25. Same appearance; the water has continued to rise in
A. This flask is opened; it smells very bad.
May 22. End of the experiment. The controls B and B' are in
foul decay; through the microscope we see in it many vibriones, but
no more distinct muscular fibers; only a few of Bowman's disks.
For some days we have noticed that bubbles of gas are escaping
through the pores of the cork in A'. The meat has become red, but
it is firm and stiff. It smells bad and is negative to reagents. Through
the microscope we see a few scattered vibriones; the muscular fibers
have remained well striated. The air of this flask contained 75% of
gas soluble in a potash solution.
Fermentations by Organisms 805
Experiment CCCXCIV. June 19. Temperature 18°.
Placed in two flasks with cork stoppers water in which fragments
of meat have been macerated:
A. Kept as control.
B. Cork pierced by a hole, flask shaken until all its walls are wet,
then placed in the large mercury receiver, in which compression is
made to 20 atmospheres with 88% of oxygen. The pressure therefore
corresponds to 88 atmospheres.
June 24. Temperature 19°. The pressure is still 13.5 atmospheres.
A is red and smells bad. Decompression is made and B is immediately
sealed; it is amber colored and seems to have no odor.
July 6. A is very red, rather alkaline; its odor is foul; there is no
mold on the surface of it; the very abundant precipitate contains
great numbers of very active vibriones, whose extremity ends in a
refracting enlargement, and also very active bacteria termo. (The
microscopic observations are made with the aid of M. Gayon, assistant
to M. Pasteur, at the Normal School.)
B had begun to redden a few days before; the cork was evidently
imperfect. The liquid is covered with greenish mold, consisting of a
penicillium with elliptical glossy spores (virens?); it is very slightly
alkaline. It exhales a faint odor of mold, but not of putrefaction.
There are no vibriones in it, but very small and very active bacteria,
and besides, long filaments of unknown nature.
Experiment CCCXCV. June 26, 1874. Temperature 19°.
Two thin pieces of meat are placed each in a flask:
One, A, is corked and kept as control.
The second, B, is corked, the cork pierced by a hole, then taken
to 15 superoxygenated amospheres. I added a little water, then shook
it so as to wet the walls and the cork.
July 21. Decompression made. A has smelled very bad, for some
time, through the cork, and is evidently entirely decayed. B is yel-
lowish, seems wholesome, and exhales no odor. The cork has been
almost entirely driven in. However I cover the whole orifice of the
flask with boiling wax.
August 3. Same condition.
The flasks are kept the rest of the year, and the meat in B keeps
the same appearance.
January 16, 1875, I show A and B to the Society of Biology. A
is completely rotten. B has exactly the same appearance as on July
21.
June 28, 1875, I show these flasks to the Academy of Sciences;
same appearance.
August 3, opened in the chemistry laboratory of M. Chevreul,
before M. Cloez; sourish, agreeable odor; slightly acid reaction. The
flask being broken, right in the laboratory I place the meat, without
precautions, in a flask with a ground stopper.
August 7, same odor and same appearance; no trace of putre-
faction.
Experiment CCCXCV I. June 25. Two pieces of meat, weighing 31
gm., are cut in similar form.
806 Experiments
One, A, is hung in a bell of 11.5 liters full of air, with hydraulic
seal.
The other, B, is placed in the glass cylindrical apparatus (capacity
650 cc.) at the bottom of which are a few cubic centimeters of water.
Compression is made to IOV2 atmospheres, with air containing 81.1%
of oxygen (tension 850 = 42.5 atmospheres of air), and then the
apparatus is shaken so as to wet all its walls.
June 30. A, horribly rotten, covered with mold; the air contains
16.3% of oxygen, and 2.8% of carbonic acid.
Therefore 522 cc. of oxygen were consumed, and 328 cc. of car-
bonic acid were formed.
B. Amber colored; no odor. The air has retained almost exactly
its original composition, since it contains 80.4% of oxygen and no
carbonic acid.
Therefore 49 cc. of oxygen were consumed. Pressure lowered to
2.75 atmospheres; oxygen tension: 220 = 11 atmospheres.
July 12. B left in the same air; same appearance; still the same
odor.
But the air contains only 69% of oxygen, with 12% of CO,.
Therefore 210 cc. of oxygen were consumed, and 21 cc. of car-
bonic acid freed.
The pressure is lowered to 2.5 atmospheres; the tension is only 172
= 8.6 atmospheres.
July 21. Same pressure, same air. The appearance is the same;
there is no odor.
The air contains only 57,2% of oxygen, with 23% of CO2.
Therefore 1583 cc. of oxygen were consumed.
July 27, same appearance; still no odor.
Without uncorking the apparatus, I empty it completely, ventilate
it with oxygen, and raise the pressure again to 10 V2 atmospheres. The
air then contains 77.6% of oxygen, and 1.2% of CO=, oxygen tension
814 = 40.7 atmospheres of air.
At the same time, I suspend in a bell of 15.5 liters a piece of meat
weighing 20 gm. C.
August 3. B. The pressure has been maintained; the meat has
still the same appearance. The air, which has no odor, contains 74.9%
of oxygen and 3.2% of CO..
We see easily that, applying it to 100 gm. of meat, 390 cc. of
oxygen have been consumed, and 397 cc. of CO- formed.
C. The meat is alkaline, foul. The air contains 16.2% of oxygen
and 3.6% of CO,.
Therefore, per 100 gm. of meat, 2295 cc. of oxygen have been
consumed and 3605 cc. of CO, freed.
August 5. Decompression made for the meat which was at 10
atmospheres. It is yellow, quite firm, and has no odor.
I put it in a test glass which had been kept in boiling water, and
close it with a rubber stopper which also had been kept a long time
in boiling water.
January 18, 1875. The meat has kept nearly its original appear-
ance. When opened, it is hardly softened, but smells very bad. Nega-
tive to reagent papers.
Fermentations by Organisms 807
Experiment CCCXCVII. July 21, 1874. 6 o'clock in the evening.
Pieces of meat placed:
A. In a corked matrass;
B, in a similar matrass, the neck of which I draw out in a flame,
leaving only a little orifice. I put it into the iron apparatus, and raise
the pressure to 15 superoxygenated atmospheres.
July 22. The pressure has fallen; I take B out, and shake it so that
all the walls are wet. Then I put it back and raise the pressure to 8V2
superoxygenated atmospheres.
A begins to smell bad.
July 23. Taken to 12 superoxygenated atmospheres.
July 24. Taken to 15 superoxygenated atmospheres.
July 30. The pressure is 14 atmospheres; I make the decompres-
sion, and close the tapering end of B with a flame; no odor, amber
color.
A smells simply horrible.
January 17, 1875. Presented to the Society of Biology. A is a mass
of decay horrible in appearance and odor.
B, which I do not open, has retained its original form and appear-
ance. One merely sees some white spots which seem to be fat.
May 27, 1875. A is horrible; no fibers recognizable through the
microscope.
B has burst in the night; the meat is amber colored; it has kept
its consistency, its fibers with their striae; slightly alkaline; rather
weak odor of decay.
Experiment CCCXCVIII. January 22. Strips of meat, each weigh-
ing 20 gm., suspended:
A. In the glass compression apparatus at 5 atmospheres of air,
which represent 3250 cc. of air.
B. In a bell containing 2500 cc. of air, at normal pressure.
C. In a bell of 7100 cc, at a half -atmosphere.
January 26. The three pieces of meat have an alkaline reaction. A
has a slight odor. B smells considerably worse than C.
The air of A contains 20.4% of oxygen; that of B 16.5%; that of
C 19.2%.
From these figures we draw the conclusion that in apparatus A
100 grams of meat have consumed 81 cc. of oxygen; in bell B, 550
cc, and in bell C, only 300 cc
Experiment CCCXCIX. January 28. Strips of meat, each weigh-
ing 39 grams, placed in the same apparatuses as in the preceding
experiment:
A. At 3 atmospheres of air, potash solution in the bottom of the
apparatus.
B. Normal pressure.
C. A third of an atmosphere.
February 2. A little odor in all; all the meat alkaline.
A contains 12.9% of oxygen. B 16.1%. C 18.2%. Therefore per
100 grams there was a consumption of -oxygen: in A of 405 cc; in
B of 313 cc; in C of 103 cc.
808 Experiments
We must note that the oxygen tension had diminished in A, since
at the end of the experiment it was only 12.9 x 3 = 38.7, that is, less
than 2 atmospheres of air.
Experiment CCCC. February 3. Strips of meat weighing 39 grams.
Same bells; but a solution of potash at the bottom of the bells, and
papers saturated with potash on the walls:
A. Normal pressure.
B. A third of an atmosphere.
February 8. The air in A contains 10.9% of oxygen; that of B
15.6%. No carbonic acid.
Whence, per 100 grams, consumption of 249 cc. in A; of only 141
cc. in B.
Experiment CCCCI. February 10. Strips of 43 grams. Same appa-
ratuses. Potash in both.
A. Normal pressure.
B. 3 atmospheres of air.
February 13. The air in A contains 20.1% of oxygen; that in B
18.9.
Whence a consumption, per 100 grams: in A of 1'9 cc. of oxygen; in
B, of 38 cc.
Experime7it CCCCII. February 16. Strips of meat weighing 50
grams each. Potash in the receivers.
A. Normal pressure. Bell containing 2.450 liters of air, that is,
512 cc. of oxygen.
B. Cylindrical glass apparatus, at 4 atmospheres of air, containing
a quantity of oxygen corresponding to 504 cc, at normal pressure.
February 19. A. Bad odor; its air contains 16.8% of oxygen.
B. Odor not quite so bad; the air contains 16.4% of oxygen.
Whence, per 100 grams, consumption in A of 101 cc. of oxygen;
in B of 109 cc.
Experiment CCCCIII. February 22. 30 grams of meat. Same
apparatuses as in the preceding experiment. Potash in both:
A. Normal pressure.
B. 4 atmospheres of air.
February 24. No odor in either.
The air of A contains 21.0% of oxygen; that in B 20.8%.
Experiment CCCCIV. March 17. Pieces of meat and water; in 2
small matrasses tapered in a flame.
A. At normal pressure.
B. B'. At 15 atmospheres of a compression made with air con-
taining 80% of oxygen.
March 26. Decompression. A rotten, foul. B has no odor and is
negative to reagent papers. I close B' with the flame.
May 15. B' has a good appearance; the liquid in which the meat
is lying has the natural light red color.
June 10. The appearance of.B' changed a few days before; it has
lost its light red color. During the night of June 9 - 10, the matrass
burst; the pieces of meat have a foul odor, with a slightly alkaline
Fermentations by Organisms 809
reaction; but they have kept their form, and the muscular striae are
easily seen through the microscope. A, on the contrary, is a mass
of horrible decay, and the striae cannot be recognized.
Experiment CCCCV. May 28. Meat in pieces, in 2 matrasses
drawn out in a flame and open at the extremity.
A. Left in open air.
B. Placed at 8 superoxygenated atmospheres.
Since the apparatus has a leak, compression is made several times,
up to 23 superoxygenated atmospheres; for several days the pressure
remains at 15 atmospheres.
June 26. A has been horribly decayed for a long time.
B. Has no odor; is amber colored.
June 28. I present the matrass B to the Academy of Sciences; I
open it in the meeting; the meat is negative and has only a slight sour-
ish odor, not disagreeable.
I recork the matrass without special care, with a hollowed out
cork, and take it to the laboratory.
July 3. No odor.
July 11. Very slight odor.
July 19. The meat is covered with mold, but does not have an
odor of decay.
Experiment CCCCV I. November 29. Barometric pressure 758 mm.;
temperature 14°. From the top of three bells pieces of meat are hung,
each weighing 25 gm. A solution of potash at the bottom of each bell
will absorb the carbonic acid as it is produced.
The cork of the bell allows passage of an elbow tube, the extrem-
ity of which, being immersed in mercury, will serve as a manometer.
Bell A (4.6 liters) contains normal air.
Bell B (1.9 liters) contains air with 45.5% of oxygen.
Bell C (1.5 liters) contains air with 91.7% of oxygen.
December 4. The bells are opened and the air analyzed; the b'aro-
metric pressure is 735 mm.; temperature 14°. The meat in bell C
does not smell as bad as the others.
The absorption of C02 has caused a drop of 2.7 cm. in bell A,
one of 10 cm. in B, and 10 cm. in C. There is no carbonic acid in any
of the bells.
The air in A now contains only 17.2% of oxygen; that in B only
35.3%; that in C still contains 91.5%.
Simple calculations, in which account is taken of the barometric
pressure and the difference in tension in the bells, show that:
A, which had at its disposal 961 cc. of oxygen, consumed 258 cc. of it
B, which had at its disposal 867 cc. of oxygen, consumed 284 cc. of it
C, which had at its disposal 1376 cc. of oxygen, consumed 183 cc. of it
If we consider first those of our experiments which dealt with
decreased pressure, we see clearly that in rarefied air putrefaction
was considerably delayed and oxidation diminished.
In Experiment CCCXCII, whereas a certain weight of muscles
had, in a certain time, at normal pressure consumed 524 cc. of
810 Experiments
oxygen and formed 514 cc. of carbonic acid, the consumption of
oxygen at a half-atmosphere had dropped to 343 cc. and the pro-
duction of carbonic acid to 418 cc. The same result in Experiment
CCCXCVIII, in which the consumption of oxygen had dropped
from 550 cc. to 300 cc, for the same change in pressure; further-
more, meat kept in decompressed air did not smell nearly as bad
as the other. Finally, in Experiment CCCXCIX, at a third of an
atmosphere, the consumption of oxygen was exactly a third of
that at normal pressure.
But these results are not very extraordinary; it has been known
for a long time that putrefaction does not take place in a vacuum,
and it was quite natural to think that it would become less active
in proportion as the air was more rarefied.
The effects of increased oxygen tension were much more inter-
esting to study.
The most salient fact shown me by the experiments is that in
air which is sufficiently compressed putrefaction does not take
place, that no disagreeable odor appears, and that the muscle keeps
its normal appearance, except its color; its microscopic structure is
not perceptibly altered (Exp. CCCXCIII and CCCCIV) .
Almost all the experiments reported above present remarkable
examples of this fact.
But that is not all; when the excess pressure is reduced, and
when sufficient precautions are taken to protect against germs
brought from outside, putrefaction does not appear; so that for
weeks, for months, meat in a fresh state can be kept at normal
pressure. I call particular attention to this point of view in the
experiments in which I cooked and ate meat kept thus .for 20 days
(Exp. CCCXCI) , or a month (Exp. CCCLXXXVIII) .
To secure conclusive and constant results, the greatest precau-
tions in detail are necessary. I did not always take them at the
outset; whence there result, in certain of the preceding experi-
ments and in others on blood, milk, etc., apparent exceptions, which
I included nevertheless, because they are instructive.
And so, in my first experiments, when I wished to preserve a
substance, after subjecting it to compression, I closed with a good
cork stopper the flask in which it was placed; this stopper was
pierced by a hole, and when I had withdrawn the flask from the
apparatus, I applied over this small orifice a drop of melted wax,
with which, moreover, I sealed the whole stopper.
I soon found out that this precaution was insufficient. The
stoppers, even when new, well washed, and heated, too often con-
Fermentations by Organisms 811
ceal germs which are still active. I then had recourse to matrasses,
balloons, tubes, which I tapered in a flame, after having placed the
experimental substances within; the almost capillary hole of the
part tapered out permitted an equilibrium of pressure to be
established.
I next perceived, at my cost, that the germs which remained in
a dry state on the walls of the little receiver were sufficient, espe-
cially when we were dealing with putrefaction, with which my dis-
section laboratory was crammed, to affect the phenomena. I could
guard against these with certainty only by adding a little water
and shaking the receiver carefully, before subjecting it to com-
pression, so as to kill at the same time both the germs contained
in the substance and those on the walls which were wet.
It must not be thought, however, I make haste to say, that this
method of preservation has a practical value; meat which has been
compressed has an insipid taste which makes it disagreeable. This
taste is probably due in part to the acid developed in it during
the compression, an acid which is not volatile, nor odoriferous, and
which is probably lactic acid.
This meat, which does not decay, absorbs infinitely less oxygen
than that which remains under normal conditions. That was studied
particularly in Experiments CCCLXXXVI and CCCLXXXVII.
But the most remarkable example is furnished by Experiment
CCCXCI, in which in 20 days meat placed under a compression of
oxygen equivalent to 44 atmospheres of air consumed no oxygen
and produced no carbonic acid; whereas a similar weight of the
same meat left at normal pressure had consumed 3.5 liters of oxy-
gen and formed 3 liters of carbonic acid.
If pressure is lowered to normal, and sufficient precautions are
taken to keep out the dust of the air, the meat, which will be pre-
served without decay indefinitely, as we have just said, will con-
sume only very small quantities of oxygen. The following ex-
periment shows this clearly.
Experiment CCCCVII. February 20. 15 pieces of meat, each
weighing 1 gm., are placed in 15 tubes. Then these tubes are drawn
out in a flame and subjected to 15 superoxygenated atmospheres in
the iron apparatus.
March 3. Decompression is made carefully and the 15 tubes are
closed by the flame. The analysis of 3 of them, made immediately,
gives 70 to 80% of oxygen.
March 13. One of the tubes is broken under mercury; meat amber
in color, no odor, acid reaction. There is 6.2% of carbonic acid and
77.8% of oxygen.
812 Experiments
The piece of meat is then placed without precautions in a tube
closed with a cork (a).
In the same way, in another tube, is placed 1 gm. of fresh muscle
(b).
March 19. The piece (a) has produced very little CO2 and con-
sumed little oxygen. The piece (b) has consumed all the oxygen of
the tube, that is, 7 cc.
March 27. Another tube, opened in the same way under mercury,
contains 11.0% of CO, and 74.2% of oxygen.
The piece of meat is placed in a graduated tube full of air and
well corked (c) ; another piece, fresh, of the same weight, is placed in
the same way in a graduated tube of the same capacity (d).
April 10. Tube c contains 1.6 cc. of COa and 2.8 cc. of oxygen,
that is, 7.3% of CO, and 12.7% of oxygen; tube d contains 6.2 cc. of
CO, and 0.2 cc. of oxygen, that is, 28% of CO, and only 0.6% of
oxygen.
These results agree with those of the experiments of M. Pasteur,
showing that the consumption of oxygen by organic substances
is extremely low, when microscopic living beings are kept from
developing there. To the proofs he has furnished I shall add the
following experiment, in which the action of antiseptics has given
the same result as that of oxygen at high tension.
Experiment CCCCVIII. June 26. A. 14 grams of muscles with a
little water are placed in a corked flask, containing 590 cc. of air, and
inverted over water.
B. 40 grams, in a flask of 750 cc. are moistened with a few drops
of phenol and then shaken. The flask is corked and inverted beside A.
C. 40 grams; flask of 780 cc; I add to it 2 grams of chloral, which,
as it dissolves, whitens the meat; well shaken, corked, inverted near
the others.
July 12. A. Is decayed; exhales a foul odor; the air (strong explo-
sion when it is uncorked under mercury, so that a part of the gas
cannot be collected under the test glass) contains 35% of CO, but no
trace of oxygen.
B. No odor of putrefaction; the air contains 18.6% of oxygen and
1.1% of CO,.
C. No odor; the air contains 18.1% of oxygen and 0.9% of CO,.
And so, proportioning the figures to 100 grams of muscles, we
see that those which have putrefied have exhausted the 880 cc. of
oxygen which they had at their disposal, and formed 1512 cc. of
CO. (without counting that which escaped when the flask was
uncorked) ; on the contrary, 100 grams preserved by phenol have
consumed only 35.1 cc. of oxygen and formed 21.9 cc. of CCX; 100
grams preserved by chloral have consumed 35.3 cc. of oxygen and
formed 15.0 cc. of CCX.
Let us return now to the action of the oxygen, and let us take
Fermentations by Organisms
813
as the measure of the intensity of the phenomena of putrefaction
the consumption of this gas in a given time.
We shall state here that we are relying both on experiments
made in compressed air, and on those in which high oxygen ten-
sion was obtained by increasing not the pressure, but the percentage
under ordinary barometric pressure. We are sufficiently justified
in this identification by all that we have hitherto observed.
Experiment CCCXCII shows us that the quantity of oxygen
consumed increases with a tension corresponding to 2 and even
to 3 atmospheres of air; Experiments CCCXCIX and CCCCI give
the same result for 3 atmospheres; but Experiment CCCXCI shows,
in its first part, that there is a decrease at the tension of 4V2 at-
Fig. 74 — Oxygen consumption and carbonic acid production by a piece of
meat in an atmosphere of constant oxygen content.
mospheres; finally, Experiment CCCCII shows equality of con-
sumption at 4 atmospheres.
It seems then, at first, that the maximum consumption of oxygen
occurs between 3 and 4 atmospheres. But the question is more
difficult to settle than one would think at first, and requires experi-
ments carried on with special precautions. In fact, in Experiment
CCCXCII, for example, the air of bell D, in which the oxygen ten-
sion corresponded at first to 3 atmospheres of air, and in which
there was more active oxidation, corresponded to less than 2 at-
mospheres at the end of the experiment. One must use here an
814 Experiments
experimental device which allows one to keep the same oxygen
tension for the whole duration of the experiment and to dispose of
the carbonic acid as it is produced.
For this purpose, I set up the apparatus pictured in Figure 74.
It is a flask C (sometimes a bell) full of superoxygenated mix-
ture, proportioned in advance; at the bottom is a solution of potash
whose carbonic acid content has also been determined by means
of the mercury pump. A piece of meat, of known weight, is sus-
pended in it. The absorption of the oxygen and the fixation of the
CO. cause pure oxygen contained in a graduated test tube E to
enter the flask, bubble by bubble; a flask-valve P prevents the air
of the flask from flowing back in case its volume changes (tem-
perature, decrease of pressure, etc.). Several apparatuses are
placed thus which operate simultaneously and in identical condi-
tions, except the oxygen content of the air of the flasks. When the
experiment is over, analysis of the air of the flasks, the height of
the column of water in the test tube, and the quantity of C02 con-
tained in the potash give all the elements of the problem.
But first I had to determine the degree of accuracy of this
experimental method. It was easy to make the test by using ordi-
nary air and making several simultaneous experiments under iden-
tical conditions. Here is the result.
Experiment CCCCIX. January 18. Pieces of meat weighing 25 gm.,
in 4 bells of equal size with ordinary air.
January 22. The analysis of the potash solutions shows that the
production of carbonic acid was 195.8 cc; 197.8 cc; 204.8 cc. and
206.8 cc.
The margin for error, then, for carbonic acid is about 5%. Let
us see now the results of the experiments.
Experiment CCCCX. January 4. Pressure 745 mm.; temperature
16°. Piece of meat weighing 25 gm., at the top of 2 bells.
A contains normal air.
B contains air with 49.6% of oxygen.
January 7. We find by analysis of the bells and the potash solu-
tions that:
A has produced 232 cc. of C02.
B has produced 245 cc. of CO,.
Experiment CCCCXI. January 24. Pressure 761 mm.; temperature
12°. Same experimental set-up, 3 bells. They contain: A ordinary
air, B air with 53% of oxygen, C air with 79.7% of oxygen.
January 29. Analyzed the potashes.
A produced 223 cc. of carbonic acid.
B produced 270 cc. of carbonic acid.
C produced 250 cc. of carbonic acid.
Fermentations by Organisms 815
Experiment CCCCXII. February 1. Instead of bells, of unequal
volumes, we use flasks of small dimensions, as is represented in Figure
74.
In flask A is ordinary air; in B, air with 37.3% of oxygen; in C,
air with 61.2%; in D, air with 81%.
February 7. Experiment ended; the analysis of the potash solu-
tions shows that:
A has produced 317 cc. of carbonic acid.
B has produced 326 cc. of carbonic acid.
C has produced 393 cc. of carbonic acid.
D has produced 328 cc. of carbonic acid.
Experiment CCCCXIII. February 14. Temperature 16°. Same
apparatuses.
In flask A, ordinary air.
In flask B, air with 41.5% of oxygen.
February 17. Ended the experiment.
A produced 130 cc. of carbonic acid.
B produced 178 cc. of carbonic acid.
If we call the quantity of carbonic acid produced under normal
pressure 100 in each of these experiments, we shall obtain by
simple proportions the following figures, which show the course
of the production of carbonic acid.
Ordinary air (1 atmosphere) there are 100 cc. of C02
CCCCXII Air with 37.3% of O, (1.8 atmospheres) there are 103 cc of CO,
CCCCXIII Air with 41.5% of O, (2 atmospheres) there are 129 cc. of C02
CCCCX Air with 49.6% of Oa (2.3 atmospheres) there are 106 cc. of CO,
CCCCXI. Air with 53% of 02 (2.5 atmospheres) there are 121 cc. of CO.
CCCCXII Air with 61.2% of O, (2.9 atmospheres) there are 124 cc. of CO,
CCCCXI Air with 79.7% of 02 (3.8 atmospheres) there are 112 cc. of CO,
CCCCXII. Air with 81% of O, (3.9 atmospheres) there are 103 cc. of CO,
It appears from these figures that the maximum of combustion
in tissues takes place above normal pressure, at about three atmos-
pheres. This was the conclusion which we had already reached
in Subchapter II of Chapter IV, for combustions investigated in
living beings.
When pressures become very high, the decrease of oxidations
in the tissues becomes extremely clear. At 23 atmospheres, the
proportion of oxygen consumed has lessened in the ratio of 534 to
32 (Experiment CCCLXXXVII). In Experiment CCCXCVI, con-
sumption at normal pressure in 5 days was 522 cc. of oxygen,
whereas it was only 49 cc. in compressed air at a tension equivalent
to 42.5 atmospheres of air, and in the 9 following summer days,
although the tension had been lowered to 11 atmospheres, only
210 cc. of oxygen were consumed.
816 Experiments
We see then that the tension figure, at which the rapid oxida-
tions due to the ferments of putrefaction begin to decrease, coin-
cides exactly with that at which the fatal effect of oxygen begins
to appear. Therefore the anatomical elements of a complex organi-
zation are susceptible to the same concentration as those which live
isolated, under the form of microzoa and microphytes. We shall
gain new confirmation of these facts when we take up the effects
of compressed oxygen on plants and germination.
Similarly, Experiment CCCLXXXVI shows us that the pressure
of 21 atmospheres completely kills the microscopic beings of putre-
faction, as it kills higher animals.
Let us add finally that meat which was preserved thus intact
during compression and after compression is none the less an ex-
cellent medium for the development of microscopic organisms, and
that putrefaction occurs rapidly in it, when germs brought by the
air come in contact with it in sufficient quantity. Experiment
CCCXCIV, in which germs penetrated into the flask through an
imperceptible crack in the cork, is quite characteristic. But for
microscopic beings, as for those of great size, the crop is propor-
tional to the sowing; it is not surprising therefore that under these
conditions putrefaction in meat which has been subjected to high
compression takes place rather slowly (Exp. CCCCVII), and that
in certain cases (Exp. CCCCV) , when the chances of the experi-
ment have allowed the germs of molds, and not the vibriones of
putrefaction, to enter the tubes, putrefaction was replaced by a
microscopic vegetation.
I have sometimes seen meat kept in vessels closed by the flame
after the phase of oxygenated compression, remain in a state of
good preservation for weeks and months, then begin to putrefy;
Experiments CCCXCVII and CCCCIV give examples of this. In
this case, in my opinion, the oxygen did not kill all the vibriones of
putrefaction; it left some, merely sick, numbed, as it were, which
regained new activity in time. That happens, too, when meat has
been heated to a temperature considerably below the boiling point;
it happens in an apparatus in which a vacuum has been made by
boiling, when air is admitted through carded cotton, if the filter
is insufficient; it happens, in a word, whenever the ferments are
either in very small numbers or altered by some strange circum-
stance.
Of course I had to study the putrefaction of some other sub-
stances. I record my experiments here.
Fermentations by Organisms 817
B. Blood.
Experiment CCCCXIV. June 9. Defibrinated dog's blood.
A. 30 cc. placed in a flask at normal pressure.
B. 30 cc. in another flask closed by a cork with a hole. Placed in
the iron apparatus and taken to 12 superoxygenated atmospheres.
The pressure falls in the days following, and cannot be kept above
8 atmospheres.
June 13. B is decompressed and sealed.
June 18. A. Horrible odor; B. slight odor.
Experiment CCCCXV. June 19; 1874. Dog blood, fresh, defibri-
nated.
A. In a corked flask, ordinary air.
B. Flask closed by a stopper of cork with a hole, subjected after
agitation to 20 superoxygenated atmospheres, equivalent to 88 atmos-
pheres of air.
June 24. A. Smells very bad.
B. Decompressed, no odor, is translucent, as if varnished; I seal
the orifice of the flask with wax.
July 6. A. Wrinkled layer on the surface; repulsive odor. No
globules visible; vibriones with a shiny terminal point, quite numer-
ous, and also motionless bacilli; crystals of hemoglobin.
B. The blood has become slightly turbid; no white layer on the
surface; strange odor, very slightly putrid. Blood corpuscles pink and
extraordinarily pale; no crystals; some few vibriones with shiny point.
July 12. B. Still no putrid odor.
The stopper is merely put back on B, without being sealed again.
In the following months, it is opened frequently and closed without
precaution; the stopper even happens to fall on the floor and is put
back without any care. Nevertheless the putrid odor does not appear
clearly.
January 16, 1875. Presented to the Society of Biology.
A. Is horribly putrid.
B. Can be sniffed without disgust, but does have a slight odor.
Experiment CCCCXV I. July 21. Dog blood, defibrinated.
In equal quantities in:
A. Matrass closed with a cork stopper.
B. Similar matrass drawn out in the flame; it is subjected to 15
superoxygenated atmospheres.
July 22. A. Begins to smell bad.
B. Pressure has fallen; I take B out and shake it to moisten the
walls of the matrass; then I take it to 8V2 superoxygenated atmos-
pheres.
July 23. Raised to 12 atmospheres.
July 24. Raised to 15 atmospheres.
July 30. A. Smells horribly bad.
B. Still 14 atmospheres; decompressed; no odor; closed the pointed
end of the matrass with the flame.
A drop of this blood, examined through the microscope, shows no
corpuscles; it looks as if it were varnished.
818 Experiments
And so, as a result of compression, when the experiment has
been well conducted, the blood is preserved without putrefying,
both in the compressed air, and on being removed from the com-
pressed air. The only change consists of the varnished appearance
which it takes on, due to the fact that the hemoglobin leaves the
corpuscles and is dissolved in the serum. This always occurs,
moreover, in dead blood, and even in blood which has putrefied
in closed vessels, after the putrid fermentation is over.
Not only are the vibriones killed thus before beginning their
work, but when blood in the process of putrefaction is compressed,
the putrefaction ceases, and the characteristic odor decreases to
the point of disappearing.
But experiments on blood present a difficulty about which I
should like to say a few words now, because it caused failure in a
number of my experiments at the beginning, and because it might,
if I did not mention it, cause uncertainty in the minds of those
who would like to run control experiments on my work.
I often saw blood which had kept well in the apparatus decay
rapidly at normal pressure, even in vessels carefully closed by the
flame. When I examined these data carefully, I found that this
happened only in experiments made in tubes, never in those made
in matrasses. This peculiarity results, as I suspected immediately,
from the fact that the thickness of the layer of blood is different in
the two operative methods.
I then perceived that oxygen, even at the highest tensions, pene-
trates the blood only a little way. Example:
Experiment CCCCXVII. December 2. 100 cc. of blood are placed in
a test tube with a foot; they rise to a height of 10 cm.; compression
in the mercury bottle to 20 superoxygenated atmospheres.
December 6. Instantaneous decompression; very little gas escapes
from the liquid; no froth.
The floating serum rises to a height of 3 cm.; below is a layer
of very red blood 3 cm. thick; the rest of the blood is quite dark.
It is then quite evident that there can be an excess of oxygen
only in the superficial layers of the liquid, and that consequently
vibriones in the deep layers will not be affected by the oxygen, or
at least only slightly. Thence arises the putrefaction which ap-
pears more or less quickly, and which in one case I saw appear
during the compression; the variations result from many circum-
stances in the multiplicity of which the height of the column used
stands out definitely. One should never use blood in a thickness
of more than a half-centimeter, if one is to be absolutely certain
of succeeding.
Fermentations by Organisms 819
C. Eggs.
Experiment CCCCXVIII. June 19. Eggs beaten and well shaken.
Placed in equal quantities in:
A. Flask with stopper, ordinary air.
B. Flask closed with a cork stopper with a hole, subjected, after
agitation, to 20 superoxygenated atmospheres, equivalent to 88 atmos-
pheres of air.
June 24. A. Foul, with mold on the surface.
B. Decompressed, no odor. The flask has been uncorked by the
expansion of gases; the stopper has to be cut and replaced. The flask
therefore remains open to the outer air for about 5 minutes. I seal it
carefully.
June 28. A. Is completely mottled.
B. Appears wholesome, the yolk clearly floats on top.
July 6. A. Horrible odor; the stopper pops out when the flask is
opened; the egg is all mottled and greenish.
B. There are still two layers; yolk greenish; no odor; there is mold
on the lower surface of the stopper.
July 12. B, which was recorked without precaution, has no putrid
odor.
Experiment CCCCXIX. July 21, 1874. Beaten egg.
A. In a matrass closed with cork stopper.
B. In a similar matrass, drawn out in a flame. Subjected to 15
superoxygenated atmospheres, shaken.
July 30. A. Smells horribly bad and is mottled.
B. Decompressed; has no odor, and its two layers are very clearly
separated. I close it with the flame.
At the end of several months, B begins to coagulate in a mass.
January 18, 1875. A. Horrible odor; is only a greenish pulp, very
alkaline.
B. I open the matrass; the egg is entirely coagulated; yolk reddish;
no disagreeable odor; reaction clearly acid.
Experiment CCCCXX. May 29. Beaten egg.
A. In an open matrass, covered with a paper cone; normal pres-
sure.
B. In a matrass drawn out in a flame. Taken to 23 superoxygen-
ated atmospheres.
June 5. A. Exhales a horrible odor.
The compression apparatus has leaked; I make a recompression
several times; it finally drops to 5 atmospheres.
June 26. Decompression.
A. Is coagulated, foul, with a dark layer at the bottom of the glass.
B. Is divided into two very definite layers, not coagulated, with-
out odor.
Experiment CCCCXXI. March 17. Beaten eggs, in 2 tubes.
A. Closed with a stopper, free air.
B. Drawn out in a flame; at 15 atmospheres of air containing 80%
of oxygen.
820 Experiments
March 26. Decompression.
A. Foul odor; coagulation; I close it with a flame.
B. No odor; liquid in two clearly distinct layers; closed with a
flame.
May 15. A. Explosion when the tube is opened; foul odor; vege-
tation on the surface.
B. Not coagulated; no explosion when the tube is opened; very
slight acidity; agreeable sourish odor, like that of cider; no vegetation
on the surface; closed with a flame.
June 10. Spontaneous explosion of tube B; however, little odor.;
matter acid, coagulated.
Eggs then do not decay either during or after decompression
when they are protected from the germs of the air. But they
finally have an acid reaction, which, without developing an odor,
causes their albumen to coagulate. That would be an exceedingly
interesting chemical phenomenon to study in detail.
These different experiments then show very clearly that when
the experimental precautions which I have stressed are taken,
meat, eggs, blood, that is, the most corruptible of substances, are
preserved without putrefaction by oxygen at high tension. When
withdrawn from the apparatus and kept in closed vessels, they
remain indefinitely without putrefying, but at the same time under-
going certain changes which would make them unfit for customary
uses.
2. Coagulation of Milk.
Milk, upon which I experimented from the double point of view
of putrefaction and coagulation, caused me a good deal of trouble
on the latter score.
Experiment CCCCXXII. August 8. Milk, placed in 3 small well-
washed bottles.
A. Left at normal pressure.
B. Placed in a compression receiver and taken to 4 atmospheres
of air.
C. Taken to 7 atmospheres of air with 70% of oxygen, equivalent
to 24 atmospheres of air.
August 15. A. B. C. Milk sour; all clotted.
Experiment CCCCXXIII. January 27. Milk placed in 2 small simi-
lar bottles.
A. Closed with a cork stopper.
B. The same, but the stopper has a glass capillary tube through
it; the bottle is subjected, in the glass cylindrical receiver, to a pres-
sure of 10 atmospheres, with air containing 84% of oxygen. The oxy-
gen tension, 840, is therefore equivalent to 42 atmospheres of air.
B. Appears to be curding a little more slowly than A.
Fermentations by Organisms 821
February 3. Decompressed B and closed the hole with burning
wax. A and B have the same appearance.
May 22. A. The stopper blows out when I open the flask. Very
strong butyric odor; very acid reaction. Numerous very active vib-
riones, some of which are oval and wide, are to be seen in it.
B. The stopper does not blow out; very slight butyric odor, very
acid reaction. A few bacillus vibriones, very small and active.
Experiment CCCCXXIV. May 22. Temperature 18°. Boiled milk,
placed in four flasks well-washed with hot alkaline water.
A, A', two flasks well corked and sealed.
B, B', two flasks, closed with a cork stopper pierced by a hole,
taken to 10 atmospheres of air with 70% of oxygen, which is equiv-
alent to 35 atmospheres of air.
May 24. Decompressed B and B' and closed the holes with melted
wax.
The four flasks appear curded to the same degree.
Experiment CCCCXXV. May 26. Boiled milk, with the addition of
water alkalinized by carbonate of soda.
A, A'. Two flasks are closed and sealed.
B, B'. Two others, whose stoppers are pierced by a hole, are
placed in the cylindrical glass apparatus under a pressure of 10 atmos-
pheres of air with 70% of oxygen, or about 35 atmospheres of air.
June 1. AA' is partly coagulated.
BB' is hardly coagulated at all.
June 3. Decompressed BB' and closed the holes with melted wax.
The liquid is less clearly coagulated in BB' than in AA'.
June 26. BB' are less clearly coagulated than AA'.
BB' are neutral or hardly acid.
AA' are extremely acid.
Experiment CCCCXXVI. August 7, 1874. Boiled milk, placed in
two matrasses, in which the liquid occupies only a small part.
A, closed with a stopper of new and well heated cork.
B, drawn out in a flame, except a little hole in the extremity;
taken to and kept at a pressure of between 8 and 12 superoxygenated
atmospheres.
August 17. A, yellowish clot with mold; foul.
B, decompressed, closed with a flame; white clot.
January 18, 1875. A, yellowish mass with deep yellow skin. Smells
bad; alkaline reaction.
B, very white and very clean clot; has no bad odor.
Experiment CCCCXXVII. August 7, 1874. Boiled milk, with the
addition of alkalinized water; arranged as in the preceding experi-
ment; one of the matrasses, B, placed beside the one of the experi-
ment above.
August 17, at decompression, same difference in the general
appearance.
January 18, 1875. A, foul; yellowish with a yellow skin; alkaline.
B, fresh odor, sourish; white, clean clot; reaction quite acid.
822 Experiments
Experiment CCCCXXVIII. January 20. Boiled milk, in tubes,
diluted with water.
A, normal pressure.
B, 21 superoxygenated atmospheres; tube drawn out in the flame.
The pressure falls repeatedly.
January 25. Decompression made.
May 17. A, foul odor; thick mold on the surface; liquid yellowish
with clots.
B, very slight butyric odor, not disagreeable; acid; liquid very
white with lumps; a few globules of milk recognizable through the
microscope.
Experiment CCCCXXIX. January 20. Milk with the addition of
a solution of soda.
Experiment made at the same time as the preceding one.
May 17. The milk which was not compressed has a foul odor; the
other has no odor.
Experiment CCCCXXX. March 16. Boiled milk, in tubes.
A, normal pressure.
B, at 10 superoxygenated atmospheres, in the cylindrical glass
apparatus.
March 18. The milk is clotting perceptibly at the same time in
A and in B.
We see that for milk as for the other substances putrefaction
has been checked by compressed air; on the condition of giving
up corks and using exclusively tubes or matrasses closed with a
flame.
But coagulation was not prevented, nor was rapid acidification;
these changes did not even seem delayed appreciably. A previous
strong alkalinization of the milk did not check them either; how-
ever, in this case, an evident delay resulted.
Could it be that oxygen under high tension really has no effect
on the lactic vibriones discovered by M. Pasteur: Or could it be
that coagulation of milk is not the work of these microscopic beings,
but instead of some agent invulnerable to oxygen, as soluble fer-
ments are, as we shall see?
Before giving an answer to these questions, I had to reflect on
the experimental cause of error revealed to me by my experiments
on blood. The thickness of the layers of the liquid which com-
pressed oxygen must saturate to carry out its destructive work
might play an important part here.
I had to eliminate this harmful influence; and so I did, for ex-
ample, in the following experiments.
Fermentations by Organisms 823
Experiment CCCCXXXI. August 10. Boiled milk; placed in a layer
2 to 3 millimeters thick in two new, well- washed crystallizing pans:
A, in the open air, under a glass which kept out dust;
B, at 25 atmospheres of superoxygenated air.
August 14. Decompressed.
A has been coagulated since August 11, and smells very bad.
B is liquid, has no odor, and seems quite normal.
Experiment CCCCXXXII. May 25. On the bottom of 6 tubes a few
drops of boiled milk (depth y2 centimeter) are carefully dropped.
A. 2 tubes are closed with a flame and kept as controls.
B. The other 4, drawn out in the flame but open, are subjected to
15 superoxygenated atmospheres in the glass cylinder.
June 1. Decompressed.
A has been coagulated since May 27.
B is not coagulated; closed with the flame.
June 6. B not yet coagulated.
These experiments prove very clearly that oxygen under high
tension prevents the coagulation of milk, that is, kills the vibriones
which cause lactic fermentation. As the action of these vibriones
takes place very rapidly, to check it oxygen must be used in a
very high concentration upon a thin layer of liquid, which must
be saturated rapidly. For putrefaction, which works much more
slowly, these excessive precautions are not necessary; since milk
does not, like blood, consume the oxygen as it penetrates the liquid,
the oxygen has time to go to the bottom of the tubes and kill there
the agents of putrefaction. That explains why it is so easy by
compressed air to prevent milk from putrefying, and so hard to
prevent it from coagulating.
3. Alteration in urine.
Since the research of M. Van Tieghem, we know that the trans-
formation of urea to carbonate of ammonia is a true fermentation,
due to the development of a microphyte, of a torula.
Therefore I studied it somewhat in detail.
Experiment CCCCXXXI1I. August 8. Temperature 27°. Urine of
the day before, quite acid; in equal quantities in three small bottles
covered by paper cones, and placed:
A, at normal pressure, under a bell;
B, in the small Seltzer water receiver, at 4 atmospheres of air;
C, in the cylindrical glass receiver, at 7 atmospheres of an air
containing 70% of oxygen, which corresponds to 24 atmospheres of air.
August 11. A, quite turbid, foul, but still acid.
B, decompressed; a little turbid, a little bad odor. Taken to 5
atmospheres of air.
C, decompressed; no turbidness; fresh odor. Taken to 5 atmos-
pheres with 71% of oxygen, that is, about 18 atmospheres of air.
824 Experiments
August 15. A, completely turbid, very alkaline, horribly foul.
B, turbid, fairly alkaline, not quite so foul.
C, slightly turbid, a little alkaline, begins to smell bad.
Experiment CCCCXXXIV. May 13. Fresh urine, very acid, in
two similar flasks.
A, corked, at normal pressure;
B, taken to 10 atmospheres of superoxygenated air.
May 18. A, turbid, neutral.
B, clear, acid.
Experiment CCCCXXXV. June 19. Mixture of fresh urine and
urine already spoiled.
A, flask with a stopper.
B, flask with a cork stopper with a hole, taken to 20 atmospheres
of superoxygenated air, corresponding to 88 atmospheres of air.
June 24. A, turbid, smells bad; I close the hole in the stopper
with wax.
B, decompressed; clear, no odor.
July 6. A, strong odor; turbid; a film on the surface, in which
there are myriads of moving organisms and rounded crystals. Strongly
alkaline; to acidify a certain quantity, it is necessary to add 4 drops of
sulphuric acid.
B, no odor; turbid; film; moving protozoa, but no crystals. Not
very alkaline; a single drop of sulphuric acid acidifies the same
quantity as in A.
July 30. A is horribly foul and very alkaline; B, which had the
stopper replaced without care, has no odor and is not very alkaline.
However the two urines give, by the Yvon method, the same
quantity of nitrogen (3.5 to 3.7 per cubic 'centimeter) .
Experiment CCCCXXXVI. July 21, 1874. Fresh urine, in equal
quantities in two equal matrasses:
A, closed with a cork stopper;
B, drawn out in a flame, with a tiny orifice. Placed at 15 super-
oxygenated atmospheres; matrass shaken.
July 30. A, turbid, very bad odor.
B, clear and has no odor. While I was trying to close the matrass
with a flame, it broke; I decanted the urine into a similar matrass
which also broke, then finally into a closed tube well washed with
boiling water, and then closed with a flame.
In the following months, the turbidness in A keeps increasing;
foul odor; color deeper and deeper.
On the contrary, B remains limpid and pale in color.
January 16, 1875. Presented to the Society of Biology. A, very
dark-colored, turbid, foul; B, clear, with a slight flaky deposit.
January 18. A, dark-colored, turbid, foul, very alkaline. Analysis
by the Yvon process gives 5.8 cc. of nitrogen for 1 cc. of urine; but
by the Grc'hant process we get only 2 cc. of nitrogen, that is, 0.5
centigrams of urea; that is because the Yvon process includes the
carbonate of ammonia.
Fermentations by Organisms 825
B, clear; odor quite fresh; normal acidity. The Yvon process
gives 6.1 cc. of nitrogen for 1 cc. of urine; the Grehant process gives
6.0 cc, that is, 1.6 cgm. of urea.
May 17. Urine B, which was closed with a flame, is neutral, with
hardly any smell; there is a thick vegetation on its surface. Analysis
by the Grehant process gives 1.5 cc. of nitrogen for 1 cc. of urine,
corresponding to 0.4 cgm. of urea.
Experiment CCCCXXXVII. May 20. Fresh urine, in three tubes;
to each of them I add a small piece of Musculus paper, laden with
urinous ferment, which M. Pasteur sent me; this paper, prepared
more than six months before, is still very powerful:
A, in open air;
B and B', at 21 atmospheres of air with 81% of oxygen.
May 24. Decompression.
A, strong odor; very alkaline.
B, B', slight odor; B neutral, B' very slightly alkaline.
Experiment CCCCXXXVIII. May 28. Fresh urine, in two mat-
rasses closed with a cork stopper which is hollowed out;
A, in open air;
B, at 23 superoxygenated atmospheres, which fall slowly to 5.
June 26. Decompression.
A has been foul and turbid for some time.
B, clear with a slight deposit, no odor, closed with wax.
June 28. Presented to the Institute, closed without care, and taken
back to the laboratory.
July 11. Is covered with a green mold, but has no odor of
ammonia.
So urine is preserved with all its qualities, its color, its odor, its
normal acidity, and urea is kept in it in its original proportion.
Experiment CCCCXXXVI, which was performed with particular
care, is quite conclusive in reference to all of these properties. The
agreement of the figures given by the Grehant process and the
Yvon process for the quantity of nitrogen extracted from the com-
pressed urine shows that there was no carbonate of ammonia
formed in it, whereas there was much in the urine left at normal
pressure.
But if, as in Experiments CCCCXXXV and CCCCXXXVII, a
considerable quantity of ferment is added to the fresh urine, altera-
tion will begin. That evidently, as we have already decided in
regard to blood and milk, is the result of the fact that the oxygen
does not have time to kill the ferments before they have begun
to act upon the fermentable matter; however, even in these cases,
their action is delayed.
I must say, however, that these experiments on urine should be
resumed with special persistence; when the Musculus paper is used,
826 Experiments
there seems to be something complex, the simultaneous action of
an organic ferment and a soluble ferment.
4. Brewers Yeast.
Brewers yeast is killed by compressed air, as is shown by the
following experiment.
Experiment CCCCXXXIX. June 26. Pieces of very active brew-
ers yeast are placed:
A, in a closed flask, normal pressure.
B, in a flask taken to 15 superoxygenated atmospheres.
July 21. A, decayed, with a foul odor; no recognizable trace
through the microscope.
B, decompressed; good, fresh odor; seems wholesome outwardly
and through the microscope. However, when placed in water with
glucose in it, it decays without fermenting, turning acid.
So the yeast lost all its power and life; yet it was preserved
from putrefaction by the very agent that killed it.
It is not surprising then that at normal pressure, fermentation
by yeast proceeds more energetically than in compressed oxygen.
Examples:
Experiment CCCCXL. August 6. Brewers yeast is added to equal
quantities of a solution of glucose, at the bottom of four similar
tubes:
A, 2 left at normal pressure;
B, 2 taken to 10 superoxygenated atmospheres.
August 8. A, 5 cc. of liquid reduce between 20 and 30 drops of
blue reagent.
B, 5 cc. reduce between 40 and 45 drops.
So compressed yeast consumed much less sugar than the other.
Experiment CCCCXLI. May 13. 50 cc. of glucose solution are
placed in two flasks, with a piece of brewers yeast of the same weight.
A, closed, left at normal pressure.
B, taken to 10 atmospheres of an air with 76% of oxygen; tension
corresponding to 38 atmospheres of air.
May 18. A, 5 cc. of the liquid reduce 1.3 cc. of Fehling's solution.
B, 5 cc. reduce 5 cc.
The liquid in which the yeast was subjected to compression
therefore contained much more glucose than the other.
Experiment CCCCXLII. December 2. Into each of four tubes are
poured 3 cc. of a weak glucose solution and a piece of brewers
yeast as big as the head of a pin.
A and A', drawn out in the flame, are kept at normal pressure.
B and B' are taken to 18 superoxygenated atmospheres.
December 8. Decompression; A and A' contain no trace of glu-
cose.
B and B' contain 15.6 mg. of glucose.
Fermentations by Organisms 827
5. Wine Ferments.
The same thing is true for the two fermentations which appear
so often in wine, and follow the development of mycoderma aceti
and mycoderma vini. In the following experiments, the two myco-
derms are generally used simultaneously.
Experiment CCCCXLIII. August 8. Temperature 27°. Wine de-
cidedly acid, placed in equal quantities in 3 small bottles; I add to
each a small quantity of acetic ferment in full activity:
A, left at normal pressure, covered with a paper cone turned
over it.
B, taken to 4 atmospheres of ordinary air.
C, to 7 atmospheres of air with 70% of oxygen; tension equiv-
alent to 24 atmospheres of air. •
August 11. A. The wine is covered with a very definite white
membrane.
B, very slight film over almost the entire surface.
C, a few very slight small spots.
B and C remain under compression.
August 15. A, very thick membrane.
B, pellicle a little thicker than on August 11.
C, spots as on August 11.
Experiment CCCCXLIV. August 15. I add to wine placed in a
thin layer at the bottom of two matrasses films of mycoderm of
vinegar.
A is closed and inverted over water.
B is agitated for a long time by a current of almost pure oxygen;
then I close the matrass, and invert it beside A.
August 17. A is covered with a white film of mycoderms.
B has nothing on the surface.
August 19. A, thick pellicle.
B, slight film.
August 21. A, quite thick membrane.
B, the film slightly thickened.
Experiment CCCCXLV. January 27. Ordinary wine placed in
two vials; on the surface is spread a little mycoderm from wine ex-
posed in the laboratory, on which had been sown mycoderma aceti.
This wine contained 11.9% of alcohol and its equivalent' of
acidity was 0.08.
A, with a cork stopper, and left at normal pressure;
B, closed similarly with a stopper with a hole, and taken to 10
atmospheres of an air with 84% of oxygen; tension equivalent to 42
atmospheres of ordinary air.
February 3. A, slight film on the surface.
B, decompressed; nothing on the surface; stopper sealed with
wax.
February 17. A, thick membrane.
B, nothing on the surface.
May 24. Shown to the Committee of the Academy of Sciences.
828 Experiments
A, turbid, with a thick layer of mold on the surface; micro-
scopic examination shows that there are present only mycoderma vini
and some ferments of bitters.
When filtered and tasted, it is a horrible parody of wine. It has
only 9% of alcohol and its equivalent of acidity is only 0.045.
B, very clear, but very much "faded"', with a slight deposit of
coloring matter, in which are present a little mycoderma vini and
numerous filaments of ferment of bitters.
As for the taste, it is not acid, but rather a little bitter, arid is
like good Burgundy which is too old; it was a very mediocre wine.
It still contains 11% of alcohol and its equivalent of acidity
is 0.07.
When exposed to the air, the next day it is extremely acid and
quite unfit for prinking.
(The chemical analyses were made in the laboratory of M.
Schutzenberger, and the microscopic examinations were made by M.
Gayon.)
Experiment CCCCXLVI. February 24. Fine Burgundy wine.
A, kept as control in a full flask, well corked and lying on its
side.
B, flask almost full, at normal pressure; I sow on top of it myco-
derm of vinegar, and close it.
C, large test glass with a strong stopper of new cork with a hole
in it. I sow on top of it more mycoderms than on B. Taken to 10
superoxygenated atmospheres.
March 1. B is covered with mycoderms.
C, which I decompress in 24 hours has no sign of them; I seal
the hole in the cork.
May 17. The three flasks are taken to the laboratory of M. H.
Ste.-Cl. Deville, and uncorked before MM. Deville, Boussingault,
Debray, etc.
A, fine red color; no deposit. Very firm in taste, no bitterness.
B, horrible weak wine, turbid, pale.
C, color very fine, a little amber. Deposit abundant, very adher-
ent. Agreeable odor. Taste not acid, but a little flat and definitely
bitter, although not too disagreeable. Absolutely like our good Bur-
gundy wines, when they begin to be slightly bitter.
Experiment CCCCXLVII. June 19. Ordinary wine; placed in two
flasks and in it are sown mycoderms very active in the laboratory.
A, well closed; normal pressure.
B, closed, with a hole in the cork; taken to 20 atmospheres of air
with 88% of oxygen, corresponding to 88 atmospheres of air.
June 24. A, covered with mycoderms.
B, decompressed, without mycoderms, but with a deposit of color-
ing matter; so it is "faded". Well sealed.
July 6. A, clear wine, rosy, with a film of mycoderma vini on the
surface, and a gelatinous, flaky deposit, containing much mycoderma
aceti. Strong odor of vinegar. To neutralize the acidity, I had to use
a quantity of lime water 2.3 times greater than for B.
Fermentations by Organisms 829
B, clear, pale; on the surface, iridescent film, without organisms;
deposit of coloring matter. Very weak acid odor.
Experiment CCCCXLVIII. June 26. Good Burgundy wine in a
flask taken to 15 atmospheres of superoxygenated air.
July 21. Decompressed. Very pale color of Rancio wine. No longer
has any bouquet. No acidity; very weak, with a slight taste of boiled
wine.
Experiment CCCCXLIX. July 21, 1874. Ordinary wine, in two
matrasses one quarter full.
A, sowed mycoderms of wine; closed, sealed, at normal pressure.
B, sowed similarly; the matrass is drawn out in the flame, and
taken to 15 superoxygenated atmospheres.
July 30. A, covered with mycoderms.
B, without mycoderms, but pale, with adherent deposit. Decom-
pressed, closed with a flame.
January 18, 1875. A, very thick membrane on the surface; very
pronounced acetic odor; taste of vinegar. The acidity, measured by
soda and litmus, is 6 times stronger than in B. It turns the solution
of potassium bichromate green in sulphuric acid; therefore it still
contains alcohol.
B, color very pale; very thin films on the surface and on the
walls of the vessel; definite winy odor, taste not very acid, an
extremely weak wine. Still contains alcohol.
Experiment CCCCL. May 20. Wine in tubes, on the surface of
which mycoderms have been sown;
A, in open air, covered with an inverted cone.
B, at 21 atmospheres of an air with 81% of oxygen.
May 24. Decompressed.
A, thick layer of mycoderms, liquid turbid.
B, "faded", yellowish; precipitate of coloring matter; no myco-
derms; clear liquid.
I boil wine in balloon flasks; during the boiling, I close each flask
with a stopper furnished with a long tube curved and drawn out,
through which the air enters slowly, cooling as it enters.
When the liquid is cool, I open the flasks for an instant and throw
into one, A', the contents of tube A; into the other, B', the contents
of tube B.
May 31. A', thick pellicles.
B', no mycoderms.
Experiment CCCCLI. May 28. Wine in a matrass; mycoderms
sowed on the surface;
A, open air;
B, at 23 superoxygenated atmospheres, which in the last days of
the compression, fall to 5.
May 31. A is covered with a continuous film.
June 26. Decompression.
A, thick layer of mycoderms; liquid very turbid.
B, liquid very clear, with deposit of coloring matter; nothing on
the surface.
830 Experiments
So under the influence of oxygen at high tension, the mycoderm
which consumes the alcohol entirely and the one which merely
transforms it into acetic acid are absolutely killed. The wine thus
retains its alcohol and its acid content (Exp. CCCCXLV) .
The effect of the oxygen begins to appear before the tension
which corresponds to 5 atmospheres of air (Exp. CCCCXLIV.)
However the wine undergoes certain alterations. The coloring
matter is precipitated in the form of films adhering to the vessel,
it "fades" more or less completely, and sometimes has a beautiful,
slightly amber color (Exp. CCCCXLV) , sometimes a tint like
Rancio wine (Exp. CCCCXLVIII) or finally an almost entire loss
of color (Exp. CCCCXLIX).
In taste, the wine appears to age rapidly (Exp. CCCCXLVI) ; it
even becomes quite bitter (Exp. CCCCXLV) or very much weak-
ened (Exp. CCCCXLVI) . It loses its bouquet, and sometimes has
a slightly cooked flavor (Exp. CCCCXLVIII) .
In a word, the wine appears to undergo the alterations produced
by excessive heating, brought on by contact with the air.
I will call attention to the fact that in all these experiments
the pressure was extremely high, carried no doubt far beyond
what would be needed to kill the germs. A weaker pressure per-
haps would not change the wine, and yet would preserve it from
harmful fermentations. Perhaps it would even be slightly im-
proved, as happens in the case of harsh and raw wines when they
are heated in accordance with the rules established by M. Pasteur.
Besides, the wines were tasted after a fairly long time. Possibly
if they had been tasted immediately, a certain improvement would
have been noted.
All these questions, moderately interesting from the scientific
point of view, take on a considerable importance when considered
from another point of view. However, I could not turn aside unduly
from my general studies to investigate them, and after noting the
preceding facts, I had to postpone until another time detailed re-
searches and practical applications, if possibly there are any.
I merely report here an experiment which proves that the limit
at which oxygen at high tension acts unfavorably on wine is quite
low; hence we conclude that its favorable concentration, if there
is one, as the preceding experiments seem to indicate, might be ob-
tained industrially, since ordinary air could be used.
Experiment CCCCLII. July 15. Good red wine in two sealed bottles
the corks of which are pierced by a hole.
A, in the air, upright,
Fermentations by Organisms 831
B, at 10 atmospheres of air, upright.
July 29. Decompressed. The appearance of A has not changed.
B is violet colored, with a colored precipitate, abundant, adhering
to the vessel.
October 4. Tasted. A, good taste, quite good bouquet.
B, colorless, bouquet lost, smells flat.
6. Molds.
In a great number of experiments, generally made with another
purpose, several of which have already been reported, I have ob-
served that oxygen at high tension kills microscopic organisms,
animal or vegetable, besides ferments. Liquids suited to the de-
velopment of infusoria contain no trace of them after a certain time
in compressed oxygen; they are completely purified of them, when
they already contained them, both animal and vegetable, both
simple monads and the highest infusoria in the series.
Evidently these facts have only a slight importance, considering
all those which we have already enumerated, and so we shall not
give a report of any special experiment. The universality of the
fatal effect of oxygen at high tension has been sufficiently estab-
lished by all the experiments reported hitherto. It would be a
strange philosophy to imagine — and yet eminent intellects have
made this serious mistake in the matter of so-called spontaneous
generation — that microscopic dimensions can give special powers
to beings of that size, and authorize in their favor infringements
of the most general rules of nature.
Quite naturally molds have behaved like the so-called higher
plants. And yet it seems worth while to report here a few experi-
ments which deal principally with them. These data may be useful,
in fact, in solving questions relating to the general theory of fer-
mentations.
Experiment CCCCLIII. June 26, 1874. Two pieces of wet bread,
measuring a few cubic centimeters, are placed:
A, in a large flask closed with a cork stopper.
B, in a small flask closed similarly but with a cork pierced by a
hole. Taken to 15 superoxygenated atmospheres.
July 21. A has for several days been in deliquescence and is cov-
ered with green mold.
B, white, firm, very fresh in appearance; no vegetation.
January 18, 1875. A is only shapeless fragments, in which there
is no sugar left; neutral to litmus.
B presents exactly the same appearance as on July 21. When
opened, it has a slight acid odor, agreeable, which is not that of acetic
acid, but is like that of lactic acid. It turns litmus a deep red ,and
owes this effect to an acid which resists prolonged boiling and com-
832 Experiments
plete dehydration. It precipitates copper reagent in abundance; it is
turned completely blue by iodine.
Experiment CCCCLIV. July 21, 1874. Bread cut in small pieces,
moistened, and placed:
A, in a closed matrass;
B, in a matrass drawn out in a flame; it is subjected to 15 super-
oxygenated atmospheres.
July 30. A, covered with mold.
B, has not changed in appearance.
January 18, 1875. A, in decay.
B, which I do not open, looks the same as on July 30.
August 3. B is opened m the laboratory of M. Cloez and in his
presence; the appearance has not changed; the reaction is slightly but
clearly acid; odor sourish, agreeable.
I call attention to this acid reaction presented by the bread in
spite of its apparent preservation and the complete lack of mold.
We had already noted a similar reaction in meat and egg, protected
against putrefaction by compression.
I observed it when I used cooked starch instead of bread to
simplify experimental conditions.
Experiment CCCCLV. July 21, 1874. I scatter over starch cooked
with a good deal of water various dusts taken from a corner of the
laboratory.
A, closed matrass, normal pressure;
B, matrass drawn out in a flame, 15 superoxygenated atmos-
pheres.
July 30. Decompressed B; while it was being closed with a flame,
the matrass broke. I immediately poured the contents into a tube
washed in boiling water, which I closed at once with a flame.
January 18, 1875. A, covered with mold, contains neither sugar
nor starch.
B, clean, without mold, contains much glucose, and is colored very
blue by the aqueous solution of iodine.
Experiment CCCCLV I. August 7, 1874. Starch cooked and much
diluted with water:
A, in a matrass closed with a stopper.
B, in a matrass, drawn out in a flame, maintained between 8
and 12 superoxygenated atmospheres, until August 17, when I decom-
press it and close it with a flame.
January 18, 1875. A, foul, neutral;
B, no change in outer appearance; sourish and perfumed odor,
recalling that of cider.
Very acid, it is colored blue by iodine and contains glucose.
M. Schutzenberger, who consented to examine this substance,
found in it volatile acids, acetic and formic, and a fixed acid, giving,
with zinc, crystals of the same form as the lactates.
Fermentations by Organisms 833
Experiment CCCCLVII. July 5, 1875. Cooked starch and water;
glass tubes.
A, closed with a flame, ordinary air;
B, drawn out in a flame; taken to 15 superoxygenated atmos-
pheres.
July 17. Decompressed; B closed with a flame.
November 16, 1876.
A, neutral, contains much glucose; no odor.
B, clearly acid; much glucose; no noticeable odor.
FRUITS. Experiment CCCCLVIII. June 26, 1874.
A, 3 entire cherries, very ripe, are placed in a small flask with a
little water.
Taken to 15 superoxygenated atmospheres.
B, unfermented juice of cherries left at normal pressure, in a
closed flask;
C, unfermented juice of cherries, placed beside A.
July 21. B, evidently spoiled, covered with mold.
A and C, in very good condition, have a rather deep color.
January 18, 1875. B is a horrible magma.
A. The cherries are very fine and very firm, absolutely just as
they were July 21.
November 30, 1876. The cherries in A still look the same.
May 1, 1877. Same.
Experiment CCCCLIX. May 28. Matrass containing: A and B,
whole cherries; A' and B', pears.
A and A' are left in the air, covered by an inverted paper cone.
B and B' are placed in 23 superoxygenated atmospheres; the
pressure gradually falls to 5 atmospheres.
Beginning with May 31, A and A' are covered with mold.
June 26. A and A' are molded, the pears in shapeless pulp.
B and B' have no mold; the cherries are brown, the pears amber
colored.
Experiment CCCCLX. January 20. Juice of pounded onion with
powdered chalk added; tubes:
A, normal pressure;
B, at 21 superoxygenated atmospheres.
January 23. Decompressed; the tubes closed with a flame.
May 17. A, neutral; abundant vegetation on the surface.
B, neutral; no mold.
Experiment CCCCLXI. July 5, 1875. Stoned cherries, to which a
little glucose is added. Placed in columns about 10 cm. high in three
tubes, taken to 15 superoxygenated atmospheres.
July 17. Decompressed; the cherries taste like cooked cherries but
too acid. Tubes closed with a flame.
November 16, 1876. The appearance of the cherries has not
changed; no explosion when the tubes are opened; cherries taste like
brandied cherries, but too acid.
By the method of oily drops, M. Dastre finds much alcohol in
them; he estimates the proportion of it at 1%.
834 Experiments
Experiment CCCCLXII. July 5. Apricots and cherries in flasks.
A, in open air;
B, at 8 superoxygenated atmospheres.
July 9. A, covered with mold.
B, without mold; the apricots have a strange pungent odor.
Experiment CCCCLXIII. July 15. Apples, pears, grapes, in separate
bottles, closed by sealed stoppers which are pierced by holes.
A, in the open air.
B, at 10 atmospheres of air.
July 29. Decompression.
A, the apples and pears are spoiling; liquid is issuing from them;
the grapes are putrefying; all of the grapes have fallen from the stalk,
which is left hanging; mold; closed with wax.
B, apples and pears have become brown, and seem cooked; grapes
well preserved; no mold; closed with wax.
October 4. A: fruits completely decayed;
B, apples and pears softened, taste like cooked fruits; grapes with
mold, but the fruit still clings to the stalk.
Experiment CCCCLXIV. September 23. Reine-daude plums, ripe,
very wholesome:
A: normal pressure;
B: 15 superoxygenated atmospheres.
September 29. A: intact; normal taste;
B: also intact in appearance; taste of cooked plums.
Fruits then are perfectly preserved, as far as form is concerned,
in oxygen at high tension; they are protected from mold. The
cherries in Experiment CCCCLVIII, kept unchanged in appearance
for 3 years, after return to normal pressure, give a striking ex-
ample of that. But their color changes, their taste especially, which
is more or less like cooked or brandied fruit. This research should
be continued from the chemical point of view, especially consider-
ing the production of alcohol noted in Experiment CCCCLXI. The
relation of these data to those noted by MM. Bellamy, Lechartier,
and Pasteur should be investigated.
Subchapter II
DIASTATIC FERMENTATIONS
I now come to the study of the effect (if there is one) of oxygen
at high tension upon the ferments which are soluble in water and
precipitated by alcohol, which are called diastatic ferments,
zymotic, or false ferments, etc.
Diastatic Fermentations 835
1. Saliva and Diastase.
The zymotic fermentation upon which I was to experiment most
frequently is that by which diastase transforms starch into glu-
cose. Besides the considerable interest presented by this phe-
nomenon, which plays so great a part in the digestion of animals
(saliva and pancreatic juice) , in their nutrition (hepatic glyco-
genosis), that of plants and germination, I was influenced by the
ease with which one can measure its effects exactly.
The first question to be settled was whether the diastatic ferment
is killed by oxygen at high tension, as the organic ferments so
surely are. The following experiment will give the answer.
Experiment CCCCLXV. June 26. Diastase is dissolved in a little
water and placed in two tubes:
A: normal pressure.
B: at 15 superoxygenated atmospheres.
July 21. Decompressed B, which has no odor and has retained the
most energetic transforming power, whereas A smells bad and no
longer has any effect on cooked starch.
Experiment CCCCLXVI. February 16. Diastase and water in a
tube drawn out. Placed at 15 atmospheres of superoxygenated air.
May 5. Decompressed, has retained all its effect. I make a new
solution of diastase in a tube which I close with a flame, as 1 also do
with the first.
May 17. The diastase which was compressed still acts upon starch;
it has no odor. The other has a butyric odor and no strength left.
So diastase, far from being spoiled by oxygen at high tension,
is preserved perfectly in it. It even appears that it remains power-
ful almost indefinitely, in all probability because of the destruc-
tion by the compressed air of the organic ferments, which would
have caused it to putrefy at normal pressure.
We get the same result when we experiment upon, not pure
diastase dissolved in water, but the complex mixture which con-
stitutes the buccal saliva. Example:
Experiment CCCCLXV II. July 21, 1874. Human saliva diluted with
water and placed in a matrass drawn out in a flame, and subjected
to 15 atmospheres of superoxygenated air.
July 30, I make the decompression and close the end of the tube
which was drawn out.
January 18, 1875. This saliva, which has no odor and appears
quite normal, neutral to reagents, has a powerful transforming effect
upon starch cooked in glucose.
So saliva is preserved in compressed air; but I must confess
that it keeps very well in open air also. Unfiltered human saliva,
836 Experiments
placed in a closed tube January 18, was still active February 12;
although a very small orifice was left open in the tube then, the
saliva still had considerable activity May 17.
The same thing is true of the pancreatic juice and in general of
the soluble ferments, which even resist beginning putrefaction.
But now, even if it is preserved in compressed air, does the
ferment retain its activity there? And does it act there with more
or less energy than at normal pressure?
Experiments will give the answer. I call attention to the fact
that I took raw starch in suspension in water, because cooked
starch is transformed instantaneously on contact with saliva.
Experiment CCCCLXVIII. July 18. My saliva, filtered, is mixed
with a certain quantity of water holding raw starch in suspension;
it is mixed carefully and placed in 3 open tubes:
A. Left at normal pressure.
B. Taken to a half-atmosphere.
C. At 8 superoxygenated atmospheres.
The tubes and apparatuses are placed in identical conditions of
temperature.
July 20. Withdrew the tubes, filtered the liquids rapidly, and
tested them with Fehling's reagent.
A. 5 cc. reduce from 75 to 85 drops of copper reagent.
B. 5 cc. reduce from 65 to 75 drops of copper reagent.
C. 3 cc. reduce from 50 to 60 drops of copper reagent.
Experiment CCCCLXIX. May 26. Filtered saliva, mixed with raw
starch in suspension in an equal volume of water. The liquid, well
mixed, is placed in equal quantities in 2 tubes, one of which, A, is
left at normal pressure, the other, B, is subjected to 15 superoxygen-
ated atmospheres.
June 3. A evidently contains much more sugar than B.
However the deposit at the bottom of tube A is colored an intense
blue by iodine, whereas that in B gives only a greenish discoloration.
Experiment CCCCLXX. January 20. Saliva, raw starch, and water.
Well mixed and placed in tubes. We make sure that the mixture
contains no glucose.
A. At normal pressure, covered with an inverted paper cone.
B. At 21 atmospheres of superoxygenated air.
Both are placed in the drying-oven, at 30 degrees.
January 25. Tested with copper reagent.
A. 7 cc. reduce 35 drops.
B. 7 cc. reduce only 14 drops.
Experiment CCCCLXXI. March 22. Saliva, raw starch, and water.
Mixture placed in tubes.
A, A'. At normal pressure.
B, B'. At 9 superoxygenated atmospheres.
March 24. Tested with copper reagent.
Diastatic Fermentations 837
A and A' contain a little more glucose than B and B'; slight, but
evident difference; examinations made with great care on white paper.
Experiment CCCCLXXII. May 25. Saliva, raw starch, and water.
Equal quantities in six tubes.
A. Three are drawn out in the flame and left at normal pressure.
B. Three at 15 atmospheres of superoxygenated air.
May 27. Analyses of the tubes by M. Dastre.
A. Contain 2.2 mg.; 2.9 mg.; 1.7 mg.; an average of 2.3 mg. of
glucose.
B. Contain 1.6 mg.; 1.9 mg.; 1.7 mg.; an average of 1.7 mg. of
glucose.
In these experiments, the transformation of starch into sugar
continued to operate in compressed oxygen, but its intensity has
evidently diminished.
But to obtain this result, one must not wait too long, but must
examine the liquids after a very few days. Otherwise, especially
if diastase was used, the result would be just the opposite, and the
compressed liquid would be richer in sugar than the other. This
happened, for example, in the following experiments.
Experiment CCCCLXXIII. June 26. Raw starch in suspension in
water, mixed with a certain quantity of diastase. Well shaken; placed
in 2 tubes:
A. Normal pressure.
B. 15 superoxygenated atmospheres.
July 21. A, 5 cc. reduce 25 drops of copper reagent.
B left under compression till then; 5 cc. reduce 40 drops.
In both there is still some starch.
Experiment CCCCLXXIV. March 1. Saliva, raw starch, water,
equal quantities in 12 tubes:
A. Six are drawn out in the flame and left at normal pressure.
B. Six are placed at 15 superoxygenated atmospheres.
March 28. Analysis of the tubes by M. Dastre.
A. 2 tubes contain quantities of glucose proportional to the num-
bers 45 and 39; hence, an average quantity of 1.7 mg.
B. 3 tubes analyzed contain quantities of glucose proportional to
the numbers 111, 119, 115; hence an average quantity of 4.6 mg. of
glucose.
That is easily explained; the diastase which had been left in the
air had altered a little, whereas that which was under compression
had kept its properties and continued to act.
2. Pepsin.
Experiment CCCCLXXV. February 16. Boudaut pepsin; three
tubes, in each of which are placed 2 grams of pepsin with 5 cc. of
distilled water.
838 Experiments
A. In the air, covered with a paper cone.
B and B'. In 15 atmospheres of superoxygenated air.
March 5. Decompression.
A. Smells rather strong and is covered with mold which forms
a stopper; very acid.
B and B'. No odor; no mold; acid.
I put B and B' each in a glass with 10 grams of cooked white of
egg which has been cut into pieces; the glasses, which are of the
same size, are next filled with water acidulated with hydrochloric
acid.
I take 2 grams of powdered pepsin, place them in 5 cc. of dis-
tilled water, and add 10 grams of the cooked white of egg, and the
same quantity of acidulated water.
The three glasses are placed in the drying oven at 38 degrees.
March 8. There remain in each glass 2 grams of insipid white of
egg.
So pepsin, after being subjected to the effect of oxygen at high
tension, behaved absolutely as before.
3. Inversive Ferment of Yeast.
The ferment which I used, like the myrosine and emulsine to be
discussed in the following sections, had been prepared by M
Schiitzenberger, then head of the laboratory of chemical research
of the Faculty of Sciences.
Experiment CCCCLXXV (2). February 16. Placed 5 cc. of liquid
in three tubes drawn out in the flame.
A. In open air, covered by a paper cone.
B and B\ At 15 atmospheres of superoxygenated air.
March 5. Decompression; I close the three tubes with the flame;
but first I make sure that the ferment in tubes A and B transforms
cane sugar rapidly into glucose.
March 15. Placed in the drying oven, in which the temperature
varies from 25 to 40 degrees.
March 25. Withdrawn from the drying oven; A, B, and B' ai*e still
potent.
May 17. A is alkaline and foul; has no potency.
B and B' are acid, have no odor, and have kept their power.
4. Myrosin.
Experiment CCCCLXXV I. February 16; in 3 tubes drawn out in
the flame; liquid to a height of 5 cm.
A. Free air, covered with a paper cone.
B and B'. At 15 atmospheres of superoxygenated air.
March 5. Decompressed; A and B act perfectly upon potash my-
ronate to give essence of mustard.
March 15. Placed in the drying oven, from 25 to 40 degrees.
March 25. Taken from the drying oven; A and B are still potent.
May 17. A, B, and B' are still potent, but the last two have more
energetic action.
Anatomical Elements 839
5. Emulsin.
Experiment CCCCLXXVI (2). February 16. This experiment was
performed at the same time and under the same conditions as the
three preceding ones.
March 15. There is much mold on the emulsin which was not
compressed; no molds on the other, any more than on the other tubes.
The formation of the essence of bitter almond on contact with
amygdalin takes place in both liquids, March 25, when taken from
the drying oven.
May 11. The emulsin which was not compressed is covered with
mold, alkaline, foul, and impotent.
The other seems fresh, has no odor, is slightly acid, and acts
energetically and rapidly.
In summary, all the soluble false ferments upon which we ex-
perimented, salivary diastase, pepsin, inversive ferment, myrosin,
emulsin, have given us the same result and have kept their char-
acteristic power after the prolonged effect of oxygen at high
tension. And even more, since the oxygen frees them of the germs
of mold, vibriones, etc., which sooner or later destroy them in the
open air, they remain themselves for an apparently indefinite time.
This remarkable power can perhaps be used in practice, and
especially in therapy. It would be a good idea, I feel sure, to
substitute for powders and extracts, so harmful to the digestive
juices, the juices themselves, previously subjecting them to a
sufficient pressure, to prevent putrefaction in them. But I can
merely suggest this idea here.
Subchapter III
EFFECT OF OXYGEN AT HIGH TENSION UPON THE
ANATOMICAL ELEMENTS
After noting, in Chapter IV, the rapidly fatal effect of oxygen at
high tension upon the higher animals, we tried to analyze this
effect, according to the methods introduced by M. Claude Bernard
in toxicology. Sectioning of the nerves, examination of the heart,
use of anesthetics, and the injection of the blood of animals killed
by oxygen into the veins of other animals have showed us that the
violent symptoms which precede and bring on death, are the result
of an over-excitement of the nervous centers, so that I was led to
compare the effect of oxygen with that of strychnine and phenol.
After death, the muscles are still contractile, the nerves are
840 Experiments
excitable, the reflex acts are possible, and the heart is still beating.
But does this mean that the nervous anatomical elements alone are
attacked by oxygen? All that we have said hitherto is opposed to
that hypothesis; the considerable decrease of the intra-organic
oxidations, the death of lower animals, the death of plants and
ferments, all these phenomena show a universality of effect which
evidently must extend to the anatomical elements of the higher
animals.
Yet I could not be satisfied in this case, any more than in any
other, with conclusions drawn from analogy. I thought direct
experiments necessary; but I confess that, seeing how well they
agreed with what appeared so probable, I did not make their
number very great.
Experiment CCCCLXXVII. February 20. The hind-quarters of a
frog are cut in two, following the vertebral axis.
A. One of these parts is left at normal pressure, hung in a closed
test glass, at the bottom of which water is placed to prevent desic-
cation.
B. The other is hung similarly in the cylindrical glass apparatus,
in which the pressure is raised to 10 atmospheres of air with 80% of
oxygen.
February 24. A. The sciatic nerve is no longer excitable; the
muscles still contract under the influence of a rather weak current;
they are neutral in reaction.
B. Neither the muscles nor the nerves are excitable by the strong-
est currents. There is evident rigidity, and the muscles are very acid.
Experiment CCCCLXXVIII. March 2, 2 o'clock. Halves of frogs
arranged as in the preceding experiment; A at normal pressure, B
at 15 superoxygenated atmospheres.
March 3. 4 o'clock. A: sciatic nerve quite excitable; muscular
contraction very strong and very sudden, as in the normal state.
B: The sciatic nerve can no longer be excited by any current.
The muscles still contract; but the contraction is slow, resembles a
kind of a cramp, and lasts after the stimulus has ceased.
Experiment CCCCLXXIX. April 8. Experiment still arranged in
the same way; A at normal pressure, B at 3 atmospheres of air con-
taining 50% of oxygen, which corresponds in tension to 7.5 atmos-
pheres of air.
April 10. A. Muscular contractions obtained with the inductor-
ium, the movable coil being 16 cm. from the exterior of the fixed coil.
B. To get contractions, it is necessary to bring the coil to 5 centi-
meters. The contraction is accompanied by contracture.
Experiment CCCCLXXX. June 12, 4 o'clock. The hearts of 4 frogs
are removed. These hearts are placed 2 by 2 in a capsule in which
they lie in the vitreous humor of a dog.
A. Left at normal pressure.
Anatomical Elements 84]
B. Compressed in the cylindrical glass apparatus to 10 superoxy-
genated atmospheres.
6 o'clock. A. The hearts are still beating occasionally, especially
the auricles; they can be stimulated.
B. They have completely stopped, and cannot be revived by stim-
ulation.
These data show that muscular contractility, motor nerve ex-
citability, and the rhythmic action of the nerve ganglia of the heart
stop much sooner in oxygen under high tension than under normal
pressure with ordinary air. In other words, the muscular, nerve,
and ganglionic anatomical elements, like the free elements which
constitute the ferments, are killed by compressed oxygen.
Other researches, in which I used the method of animal grafting,
the only one which could inform us on this point, show that not
only the vital properties of the higher order, the animal order, are
destroyed in the muscular and nervous elements, but that all the
anatomical elements are killed by oxygen at high tension. In
fact, the grafts carried out with parts subjected in advance to its
effect were absorbed without having become adherent.
Experiment CCCCLXXX1. March 15. Tails of rats, with skin re-
moved, are hung in closed glass tubes, with a little water at the
bottom.
One of them, A, is left at normal pressure.
The other, B, the stopper of which is pierced by a hole, is subjected
to 10 atmospheres of superoxygenated air, from March 16 to March
20. Temperature 12 degrees.
March 20. A smells rather bad. B no odor.
Grafted under the skin of the back of two rats.
No complication.
July 16. Graft A has taken root perfectly.
B is almost entirely absorbed.
Experiment CCCCLXXXI (2). March 22. Tails of rats, with skin
removed, hung in tubes, above a little water.
A. Normal pressure.
B. At 9 superoxygenated atmospheres.
March 24. Grafted on two rats.
No complications.
June 1. A, graft has taken root perfectly.
B. Almost entirely absorbed.
The transfusion of blood, which is only a particular case of the
general method of animal grafting, also shows that the blood
which has undergone the prolonged action of compressed oxygen is
incapable of maintaining life; its anatomical elements, its cor-
puscles, are killed and their introduction into the organism even
causes death. Example:
842 Experiments
Experiment CCCCLXXXII. April 20. 100 cc. of dog blood, defibri-
nated, are shaken continuously for 18 hours in the apparatus pictured
in Figure 45, with oxygen compressed to 18 atmospheres.
April 21, from a little dog (weighing 5 kilograms) 100 cc. of blood
are taken, a loss of blood which certainly would 2 not have killed him,
and into his femoral vein is slowly injected the 100 cc. of blood which
had been shaken and deprived of free gases.
The injection is made at 11 o'clock. Immediately after, the animal
begins to run; but he soon retires to a corner, falls into a sort of
somnolence, and dies at 5:30; his rectal temperature at this time is
29.5°.
So the anatomical elements of the bones and the cellular tissue
were killed by the oxygen at high tension; the blood acquired
toxic properties; grafts were absorbed without having made vas-
cular adherences. If they did not cause cellulitis, that is probably
because the oxygen had killed all the atmospheric germs which
might have lodged there; besides, I obtained similar results before.
We conclude from these data that the death of higher animals
in compressed oxygen, although its immediate cause is the super-
excitation of the central nervous system, as we have demonstrated,
is really due to a general effect of the oxygen upon the whole
organism. But the nervous elements, which are more susceptible,
react first, disturb the vital mechanisms, so that death occurs before
the other elements are noticeably affected.
Hence we draw again the conclusion that the death of the
anatomical elements has nothing to do with putrefaction; it is not
the first stage of putrefaction, as might have been thought with
apparent reason; it is quite a different thing, because pressure,
which hastens death, prevents putrefaction.
Subchapter IV
ON THE USE OF OXYGEN AT HIGH TENSION AS AN
EXPERIMENTAL METHOD
The data which have just been reported in the two preceding
subchapters seem to me to present considerable interest, not only
in themselves, but from the point of view of the use of oxygen at
high tension as an experimental method. We have seen, in fact,
that the microscopic organisms which constitute the true ferments
and that anatomical elements, isolated or grouped in tissues, are
killed by oxygen; that on the contrary the unformed ferments, the
Dry-rot; Venoms; Viruses 843
soluble ferments, the diastases, resist it perfectly and are even
preserved by it.
We possess then a valuable instrument of differentiation to dis-
tinguish what belongs to one or the other of the two classes of
fermentations.
If we are dealing with a true fermentation, it will be checked
completely by compressed oxygen, under a tension corresponding
to about 30 atmospheres of air, and since the ferment is killed, it
will not appear again, even when the pressure becomes normal
once more. If the fermentation is due to the presence of a sub-
stance analogous to diastase, this substance, when subjected to
compressed air, should keep its active properties there almost in-
definitely, as a subsequent experiment will show.
I make haste to say, however, that although it is very easy to
decide in this way whether a given phenomenon is a true fermenta-
tion, the method will not distinguish between a pseudo-fermenta-
tion and the result of a simple oxidation. An example taken from
the dry rot of fruit will explain my idea.
1. Dry Rot of Fruit.
Certain fruits, for example medlars and service-apples, are com-
monly attacked by dry rot, so that, since they can be eaten only in
this condition, it is generally confused with ripeness. Is dry rot
the final stage in a vital evolution of the cells of the fruit? Is it
the result of the reaction of a diastatic matter previously formed
on the tannin, which disappears during the dry rot? Or, finally,
the result of an oxidation of this tannin, the disappearance of
which takes from the fruit its disagreeable taste? Let us see first
what experiments say.
Experiment CCCCLXXXIII. September 29. Service-apples not
affected by dry rot, in good condition, placed carefully in test glasses.
A, left in open air.
B, subjected to a pressure of 10 superoxygenated atmospheres.
October 4. Decompressed.
A, beginning to rot.
B, evidently still more rotten.
Experiment CCCCLXXXIV. November 5. Medlars not affected by
dry rot.
A, at normal pressure.
B, at 17 atmospheres in air containing 78% of oxygen.
November 11. Decompressed.
A, still very hard, do not suffer dry rot until a week after.
B, completely rotten, and consequently, from the sudden decom-
pression and the escape of gases, cracked and burst.
844 Experiments
So not only was dry rot not checked by the effect of oxygen at
high tension, but, on the contrary, it was accelerated. That alone
is enough to show us that we are not dealing with an act of
cellular life.
But is it a diastatic act? Are we dealing with a direct oxida-
tion? Oxidations of this sort are not checked by oxygen at high
tension; at least, that is the case with pyrogallate of potash.
Experiment CCCCLXXXV. February 10. At the bottom of a glass
is a solution of pyrogallic acid; a little capsule containing potash
floats on the surface. The whole is subjected to 10 superoxygenated
atmospheres in the cylindrical glass apparatus.
February 13. The apparatus is shaken without being opened; as
soon as the potash touches the acid, the liquid reddens instantaneously,
certainly more rapidly than it would have done at normal pressure.
The acceleration of dry rot in compressed oxygen seems to indi-
cate that it is the result of an oxidation. The following experiment
seems to demonstrate this fact.
Experiment CCCCLXXXVI. November 12. Very hard medlars are
pounded in a mortar, and the paste thus obtained is poured into a
glass.
Two hours after, dry rot has begun on the surface of the pasty
mass.
In summary, we see, thanks to the use of oxygen at high tension,
that dry rot is certainly not an act in the life of the cells of the
fruit, but very probably the result of a direct oxidation.
2. Ripening of Fruits.
The same question can be asked about the regular ripening of
fruits. If this is a phenomenon of diastatic type, it will continue
in compressed oxygen; if it is an act of cellular life, it will be
checked. The experiment is quite difficult to carry out, because
we must use fruits which ripen easily and quickly off the tree,
which are not too subject to harmful changes, and which are small
enough to be penetrated by the oxygen rapidly.
Experiment CCCCLXXXVII. July 9. Gooseberries which are
hardly pink, beginning to ripen.
A, at normal pressure.
B, in the cylindrical glass apparatus.
July 17. Decompressed.
A, very red, sweet, tender, quite ripe.
B, have not changed color; are firm and hard, acid, with the taste
of rather tart cooked gooseberries.
Dry-rot; Venoms; Viruses 845
Experiment CCCCLXXXVIII. July 19. Plums beginning to ripen.
A, normal pressure.
B, 15 superoxygenated atmospheres.
July 26. Decompressed.
A, are eatable, softened, and quite yellow.
B, have become a dark brown color; remained very hard, ex-
tremely acid, with the odor and taste of cooked plums.
The two examples are sufficient to show very clearly that the
ripening of fruits is a vital act, due to a certain cellular evolution,
and consequently essentially different from dry rot, with which it
is often confused.
I call attention to this cooked taste which fruits acquire under
the influence of compressed oxygen. It was noted in the experi-
ments of Subchapter I, in reference to the development of mold.
It is evidently due either to an exaggerated oxidation or to the
effect of a diastatic pseudo-ferment.
3. Venoms.
The only venom upon which I could experiment is scorpion's
venom, the dried vesicles of which I kept for several years; it came
from the Buthus occitanns (Amor.) and had been sent me from the
south of Algeria.
Experiment CCCCLXXXIX. December 2. Twelve dried scorpion's
vesicles; they are crushed with a little water; then they are subjected
to the pressure of 18 superoxygenated atmospheres. (The liquid is
neutral, and has no effect upon starch.)
December 8. Decompression. The liquid part (A) is inoculated
under the skin of a big rat, and a part of the solid fragments, crushed
in water (B), is inoculated subcutaneously on the left thigh, at the
level of the sciatic nerve, of a young rat.
A quarter of an hour later, I look at rat A, and am much sur-
prised to see it already on its side, its eyes are watering and lack
sensitivity, its breathing is slow and difficult, its heart is beating
irregularly. It has, especially in the hind legs, very strong tonic
convulsions, which become remittent, and the animal dies in about a
half -hour. The muscles for some moments have exhibited very strange
fibrillary movements. The nerves no longer have any power over the
muscles.
The lungs are quite healthy; the blood in the heart is dark, on
the left as well as on the right; the heart is in diastole; the blood
turns red in the air and coagulates very well; the corpuscles are
intact; rigor mortis comes on very quickly.
Rat B is affected a half-hour after the inoculation.
At first, cries indicating local pain; then general palsy, slowness
of motion; respiration very irregular, sometimes remains 5 or 6 seconds
without breathing; the pulse follows the respiration.
846 Experiments
The left hind leg remains almost constantly stiff (local action?).
Sensitivity continues to decrease, disappearing in the eye (the cornea
- last) before the limbs. Slight convulsions, which seem to be excited
by pinching.
After three quarters of an hour, it remains' lying on its side; the
temperature drops rapidly; after an hour and a half, it is 29°.
It dies in about 2 hours.
Hemorrhage in the brain and the cerebellum; no local inflamma-
tion.
So the effect of scorpion's poison persists with all its character-
istics which I noted before,3 after the venom had been subjected
to oxygen at high tension. Besides, I was not at all surprised, be-
cause venom resists (the venom of the scorpion, without even being
dissolved by it) even the action of pure alcohol.
4. Viruses.
I was able to make a greater number of experiments on viruses.
A. Vaccine.
Experiment CCCCXC. November 10. Twelve newly born babies
are vaccinated with vaccine taken from the same child; two leave
the hospital before pustules develop; in a third, the vaccine does not
take; in the other 9, pustules develop to the number of 35 (from
1 to 6) per 54 punctures.
From the same vaccine-bearing child and from the same pustules,
Bretonneau tubes are filled, which from November 11 to November 18
are subjected to a pressure of 23 superoxygenated atmospheres.
November 18. With the compressed vaccine seven newly born
children are vaccinated. Four of them leave the next day but one,
before any development could be noted; on the other three the vaccine
takes, and produces 13 pustules (6, 6, 1) from 18 punctures.
(Operations performed by Dr. Budin, then an intern.)
So clear an experiment seems to me sufficient for drawing con-
clusions. And my conclusion is that the vaccine virus, which re-
sists so completely the action of oxygen at high tension, does not
owe its special power to living organisms (bacteria, vibriones) or
to cells (leucocytes, special corpuscles), acting like true ferments.
And yet I am far from denying that the corpuscles, irregular in
form and dimensions, which float in the vaccine, contain in them
the virulent principle, as seems very probable since the research
of M. Chauveau. But I am certain that living organisms are not
there.
Perhaps the virulent material is thus precipitated in insoluble
flakes; perhaps these corpuscles are endowed with the power of
fixing the active principle, as the blood corpuscles fix the hemo-
Dry-rot; Venoms; Viruses 847
globin and the amylaceous corpuscles of the green cells fix the
chlorophyll.
B. Glanders.
Experiment CCCCXCI. July 15. Pus of glanders sent from Alfort
by Professor Trasbot.
Equal quantities are placed in two small bottles, to a depth of
about 1 centimeter.
A, at normal pressure.
B, taken to 20 superoxygenated atmospheres.
July 21. Decompressed.
A is decayed.
B has no odor.
The same day, these two puses are inoculated in two horses.
A, has only local symptoms, evidently due to the putrid inocu-
lation, loosening of the skin and abscess; gets well.
B, dies of the glanders, after showing, M. Trasbot writes me, "as
complete an eruption as possible."
Our conclusions for the virus of glanders and the corpuscles
which it contains, upon the virulent role of which M. Chauveau
has dwelt, will be identical therefore to those which we drew from
the experiments on the vaccine-virus. Here too it is not a matter
of microscopic organisms acting like true ferments.
C. Anthrax.
The researches of M. Davaine have called attention to the part
which may be played in the infection of the virus of anthrax by
microscopic organisms, the "bacteridies," which he found exist and
are constantly present in virulent liquids. Experiments made by
dilutions, nitrations, and precipitations have led this learned phy-
sician to declare that these "bacteridies" were really the agents
of the virulence, and that, when introduced into the blood of a
healthy animal, they bring on death by their prodigiously rapid
development. So that anthrax would definitely be a true parasitic
disease.
But all these methods are open to one objection. These micro-
scopic organisms, whose nature is not yet clearly understood, may
be only the vehicle, not the original cause of the virulent agent
with which they might be merely laden.
I therefore had to begin experiments following the new method,
but taking the greatest precautions: 1). that the layer of blood be
thin enough to be penetrated by the oxygen; 2). that there should
not remain within the limits of the blood any isolated spots which
would dry out and then resist perfectly the action of the oxygen.
848 Experiments
Experiment CCCCXCII. October 6. Blood from a sheep sick with
the anthrax (sent by Professor Trasbot). This blood inoculated in
guinea pigs was followed to the fourth virulent generation,
Subjected in a thin layer to 20 superoxygenated atmospheres.
October 9. Decompressed; inoculated in a guinea pig.
October 10. The animal dies at 1 o'clock p. m.
Experiment CCCCXCIII. November 20. Professor Trasbot sends
me serum taken from a sheep which had been inoculated with the
blood of a horse which had died of anthrax; many "bacteridies."
I inject Vz cc. under the skin of a guinea pig.
November 21. The animal was found dead in the morning.
I take a little of its blood, which contains "bacteridies," mix it
with the serum which flowed from the spot of inoculation, and subject
it, in a thin layer (about 3 mm.), to the action of 20 atmospheres of
superoxygenated air.
November 30. Decompression; the blood is red to the bottom.
Injection into two guinea pigs.
December 1. Both found dead in the morning.
I give a subcutaneous inoculation with their blood to a guinea
pig and a dog.
December 2. The guinea pig and the dog are dead.
Here are experiments in which the "bacteridies" must have
been killed by the compressed oxygen, and in which nevertheless
the blood kept all its virulence; the second is particularly conclu-
sive, for in Experiment CCCCXCII the duration of the compres-
sion perhaps had not been sufficient. They prove then that this
dangerous property was not due, at least in the blood which I used,
to the existence of these tiny organisms. I also saw them corrobo-
rated by experiments which cannot be reported here but in which
I saw the virulent matter precipitated from the same blood by
alcohol, filtered, then dried, without losing its dangerous power,
which it could still transmit, as before, from generation to genera-
tion.
And yet I think it would be unwise to apply this conclusion to
all the bloods called "charbonneux" (containing the germs of
anthrax) , and that it would be necessary first to make many more
experiments, using bloods from various sources, for it might be
that several diseases are confused under the common name charbon
(anthrax) .4
Ferments, etc., Summary 849
Subchapter V
SUMMARY
As a result of these numerous experiments, we are now in a
position to state the first cause of the death of animals and plants
subjected to a fairly high oxygen tension. Let us set aside the
violent convulsions displayed by the higher animals and go to the
bottom of the phenomena.
Life is only the result of a complex and harmonious combination
of chemical changes belonging to the group of fermentations; some
are due to the direct intervention of the formed elements of the
body; others are the consequence of the action of unstable and
soluble substances, like diastase, previously formed by the action
of the formed elements. In the interior of each of the anatomical
elements the vital activity is maintained only by the action of these
substances which are created, act, are transformed, and are de-
stroyed there.
But that life may be maintained, the multiple phenomena must
go on with constant regularity, or rather harmony. When their
intensity alone is modified, without their relations being altered,
vital activity decreases, sometimes is even halted, possibly for a
long time, and then reappears when more favorable conditions
occur. This happens through cold, through desiccation, and, to
return to our subject, through decreased pressure. Seeds, pre-
served intact in a vacuum, germinate when returned to the air;
meat, which has remained fresh in a vacuum, decays when oxygen
restores activity to its vibriones.
When, on the contrary, it is not merely the quantity, but also
the quality of the chemical changes that is altered, symptoms
appear, the details of which are far from being known and which
have such consequences that even if normal conditions are re-
stored, the vital activity is not resumed. This happens through
heat, through excessive moisture, and through increased pressure.
Seeds kept apparently intact in compressed air do not germinate
when returned to normal pressure, and it is in vain that oxygen
at its usual tension comes in contact with the definitely dead vibri-
ones which swarmed upon the meat previously subjected to com-
pressed oxygen.
We do not need to go as far as death to show these important
differences. An animal subjected to decompression is seized, at a
certain moment, by convulsions, which a return to normal pressure
checks immediately: Sublata causa, tollitur ejfectus (If the cause
850 Experiments
is removed, so also is the effect) . But the convulsions due to ex-
cessive pressure continue even when the apparent cause has been
removed; that is because the real cause, the chemical change, still
exists, still operates, and excites the nervous centers.
Under the influence of oxygen at high tension, within the in-
terior of the anatomical elements, either isolated in individual cells
or grouped in tissues, chemical alterations take place, which pro-
duce lasting substances, the presence of which disturbs the harmony
necessary for the continuance of life, in the element first, then in
the complex being.
These are, indeed, rather vague terms, but this vagueness results
from the general condition of science and should not be made a
reproach against me. What do we know about the molecular
transformations which take place regularly in the tissues and in
the interior and on the surface of the anatomical elements? The
little knowledge we have I have subjected to experimentation; 1
have seen that the transformation of starch into glucose, that the
reduction of glucose into its primary elements are delayed by
oxygen under high tension. Now these are general acts which
appear, we know, in the life of a mycoderm cell, as in the cell of a
mammal or a bird. They are delayed, but yet the soluble ferment
which produces them is not altered at all, and will resume all its
activity later, at normal pressure. Why then, after this return to
normal pressure, does not life reappear, as after the suspension
due to a vacuum or to cold? Can it be that the ferment, whose
regular action has diminished, has acquired a new one, which has
produced this lasting substance the origin of which we are seeking?
Has the fermentable matter, on the contrary, changed so that now
it withstands the action of the preserved ferment?
It is very difficult to answer these questions today. All that I
can say is that the substances subjected to compression: meat, eggs,
milk, and bread, soon give an acid reaction, due probably in part
to lactic acid. It is not impossible that the presence of this acid in
the interior of the anatomical elements is the cause of death.
But without discussing any longer phenomena the inner signifi-
cance of which we cannot explain, we are justified by the numer-
ous experiments, the report of which has filled so many pages, in
saying that, under the influence of oxygen at high tension, within
each anatomical element chemical alterations take place which are
incompatible with the life of this element. When this is granted,
all the varied phenomena which we have enumerated are easily
connected and explained.
Ferments, etc., Summary 851
Are we dealing with a living being reduced in its elementary
structure to a single cell or a small number of cells? Since its
vital activity is generally manifested to us by phenomena known
by the name of true fermentations (alcoholic, acetic, lactic, and
putrefactive), its death will result in the permanent stoppage of
these phenomena, unless new ferments are sowed.
Or, to go at once to the opposite extreme, are we dealing with
an animal which is very complex in its structure? The anatomical
elements which form its tissues are threatened with death. Those
among them which in biochemistry played the part of formed fer-
ments cease to act, or lose energy of action. The phenomena of
zymotic fermentation which take place both without and within
them lose intensity and degenerate. Their personal qualities, their
contractility, their power of transmitting stimuli or of changing
them into reaction become modified and tend to disappear.
Hence come the general lessening of the chemical phenomena
of life; the decrease in oxygen consumption, in carbonic acid pro-
duction, and in excretion of urea; the appearance in the urine of
sugar which is no longer sufficiently broken down; and finally, an
enormous lowering of the temperature.
And at the same time, — since whenever a great and rapid dis-
turbance affects the equilibrium of the functions of a higher animal
(hemorrhage, asphyxia, etc.) , it is the central nervous system
which, as it is the first to be stimulated, shows by its violent reac-
tions the danger which threatens the whole organism, — there appear
these convulsions which give evidence by their persistence after a
return to normal pressure that a profound chemical change has
taken place in the tissues of the spinal cord or in the blood which
supplies them and would thus bring them a kind of poison. Last
come the muscular contractions modified in their behavior, like
cramps, such as occur in every dying muscle.
Between these two extremes, the isolated cell and the warm-
blooded vertebrate, all the intermediaries: on the one hand, molds,
algae, seeds, vascular plants; on the other, annelids, mollusks, in-
sects, fish, reptiles. The whole aggregation of living beings, in a
word, dies absolutely when the oxygen tension rises high enough.
Not one, we can affirm, would withstand a tension corresponding
to the pressure of 20 atmospheres of air. We shall return to the
inferences suggested by this unexpected phenomenon.
iSee my Memoire sur la -vita-lite des tissus anlmaitx (Annates des sciences natureltes.
Zoologie, 1866). , , . , .. A , . ,' ., ,
2 Paul Bert. Note on a certain sign of approaching death in dogs subjected to rapid blood-
letting (Memo-ire de la Societe des sciences de Bordeaux, Vol. IV, p. 75, 1866).
3 Contributions to the study of venoms: scorpion venom. Comptes rendus de la bocxeU de
biologie pour 1865, p. 136. . . . ^ , , „, ,, .
4 See the discussions of MM. Davaine, Jaillart, and Leplat: Comptes rendus de I Acadimte
des sciences, Vol. LXI, 1865.
Chapter VII
EFFECTS OF SUDDEN CHANGES IN
BAROMETRIC PRESSURE
Hitherto, I have spoken. only of the phenomena following grad-
ual changes in the amount of the barometric pressure, which are,
as we have seen, phenomena of the physico-chemical type, result-
ing from the presence in the blood of larger or smaller quantities
of oxygen. But it is only in these conditions of gradual change
that I could be brought to deny the effect of the pressure as a direct
agency, of the physico-mechaniccu1 type. Of course it may be dif-
ferent when we are dealing with sudden and considerable changes.
The experiments reported in this chapter were intended to settle
this question.
Subchapter I
EFFECT OF SUDDEN INCREASES IN PRESSURE
This part of the work will not be long. The sudden increase of
pressure seems to have no appreciable effect on animals.
At first, when it was a matter of animals previously subjected
to a very low pressure, like that discussed in Chapters I and III,
the restoration of normal pressure had no apparent ill consequence.
But on the contrary, when the decompression was very great, its
favorable effect appeared immediately, and the animal returned at
once to a normal state. We could see it then perceptibly "deflate,"
especially in the case of a herbivorous mammal, as a result of the
return to their original volume of the intestinal gases, which the
decompression had expanded.
The experiments on sudden increase of pressure were made on
rats or birds placed in the Seltzer water receiver. This receiver
852
Sudden Changes in Pressure 853
by means of a copper tube was put in communication with the large
metal receiver (Fig. 33) in which the pressure had been raised to
10 atmospheres, then the communication cock c was opened, and
the equilibrium of pressure suddenly established. The animal then
seemed to cower, to crouch, as if frightened; but after a few
minutes, regained all its liveliness.
There is no reason for surprise at these negative results, because
we have seen that workmen in caissons and divers in suits are
subjected to sudden pressures of several atmospheres without feel-
ing other inconveniences than more or less keen pains in the ears,
which pains animals do not seem to feel, since in animals, no
doubt, the Eustachian tube opens more easily than ours.
The effect of sudden increases of barometric pressure, almost
non-existent in air-breathing animals, is, on the contrary, very con-
siderable in fish provided with a swimming bladder. Whether
the bladder is closed or not, as soon as the pressure of the air
above the water in which the fish is swimming is increased a little,
the fish drops to the bottom of the vessel, from which the greatest
muscular efforts can raise it only for an instant. But after several
days during which the pressure has been maintained, it regains
complete freedom of action. That is because during this interval a
new secretion of oxygen has restored to its swimming bladder its
original volume and to its body its original density. All these facts,
which I have often witnessed, have been completely described and
explained by Dr. Armand Moreau.
Subchapter II
INFLUENCE OF SUDDEN DECREASE OF PRESSURE
BEGINNING WITH ONE ATMOSPHERE
The study of this influence presents great difficulties without
being particularly interesting. As a matter of fact, for slight de-
compressions, no matter how suddenly they are produced, the result
is almost negligible in air-breathing animals; for great decompres-
sions, it is combined with that of anoxemia, beside which it is of
only slight importance.
When a sudden drop to a half-atmosphere is made, the animals
tremble, leap, sometimes whirl, but soon recover, or at least show
only the symptoms of asphyxia due to the low oxygen content of
their blood.
854 Experiments
These evidences of distress are no doubt due to the sudden ex-
pansion of all the gaseous reservoirs of the organism, and we can
see that they are especially important in birds, in which these
reservoirs extend through the whole body; but equilibrium is re-
established almost immediately in the latter, because of the com-
munication of the air sacs with the trachea and consequently with
the interior. Mammals, and especially the herbivores, are a little
swollen by the expansion of the intestines and the stomach, but
they quickly expel the gases which distress them. This is shown
by the following experiment:
Experiment CCCCXCIV. June 9. Dog, just killed by electrical
stimulation of the heart. There is introduced into the rectum, by the
help of a little bladder which completely covers the anus, a glass
elbow tube, the end of which is immersed several millimeters in a
glass full of water. The animal is thus placed in one of the large
cylinders of Figure 27. Then decompression to 34 cm. is made as
rapidly as possible; during this time bubbles of gas quickly follow each
other escaping from the anal tube; however the abdominal wall is
evidently swelling. Air is admitted; the wall collapses; there is still
a considerable quantity of gas in the intestine.
The same effect is produced, as has been known for a long time,
in fish provided with a swimming bladder opening into the esopha-
gus, like the carp. If the decompression is not made too quickly,
one can see bubbles of gas from the bladders escaping from their
mouths; then, when normal pressure is restored, they drop to the
bottom of the water, since their density has become too great.
Under these conditions they return with difficulty to the surface
to swallow air and thus fill their bladders again; to get definite
information on this direct absorption, which might be doubted, I
made the following experiment:
Experiment CCCCXCV. June 1. A carp weighing a half-pound is
subjected, in the water, to a decompression of two-thirds of an atmos-
phere. It throws off a great quantity of air. The crystallizing dish in
which it is swimming is then placed under a bell containing a mixture
of air, oxygen, and hydrogen in proportions not fixed.
June 3. The fish dies; its swimming bladder contains 11.4 cc. of
gas of the following composition per 100: hydrogen 33.3; oxygen 16.7;
nitrogen 50.0.
Let me say in passing that carp, in the natural state, when com-
ing to the surface of the water to swallow air, do not admit it to the
bladder, and probably use it only to aerate their gills more thor-
oughly. For example:
Experiment CCCCXCVI. June 5. Carp weighing 200 gm. The ves-
Sudden Changes in Pressure 855
sel in which it is swimming is placed under a bell containing a mix-
ture of oxygen and hydrogen unproportioned.
June 9. The fish is killed. There is no hydrogen in the swimming
bladder.
Fish with closed bladders, becoming lighter than the water when
decompression is made, come to the surface and die on account of
the bursting of the overinflated bladder. This fact has long been
well known to fishermen, who pierce the bladder with a pointed
piece of iron or wood, so that the entrails may not burst and soil the
fish.
The same phenomenon (I mention this so as not to return to this
type of data again) may be observed in fish with closed bladders
kept for several days under increased pressure:
Experiment CCCCXCVII. May 4. Sticklebacks in the glass cylin-
drical apparatus. Subjected to a pressure of 2 atmospheres, they sink
to the bottom immediately.
May 10. Swim freely. Decompression made; come to the surface
immediately. When removed, they die.
So these fish had formed in their bladders a sufficient quantity
of gas to regain freedom of movement, with their original density.
But the decompression was fatal to them.
The closed air bladder is therefore very unsuitably called "swim-
ming" bladder, because it is harmful to the fish and compels it to
remain at a certain depth of water, under pain of bursting at the
surface or sinking indefinitely into the depths, if it passes the
narrow limits between which it is permitted to move vertically.
I succeeded in getting a result similar to that of Experiment
CCCCXCVII with frogs rapidly decompressed from 5 to 6 atmos-
pheres to normal pressure. When the air of the lungs expanded
enormously, the tracheal opening closed; the stomach issued
through the mouth, the lungs burst, and the body was transformed
into a sort of overinflated balloon. All that is simple and to be
expected.
But let us return to air-breathing animals. When very rapid
decompression is made, they too die almost at once. Can an im-
portant part in this death be attributed to the suddenness of the
decompression? That almost reverts to the question which we
have already asked. Is the purely mechanical or physical effect
of the decompression perceptible? The experiments reported in
the preceding chapters show that it is very slight at any rate, be-
cause an animal can, for example (Experiment CCLI), be brought
856 Experiments
very rapidly without inconvenience to a pressure of 7 cm., if the air
has a high oxygen content.
Let us now examine the results of a few experiments made
especially with a view to sudden decompression:
Experiment CCCCXCVIII. March 2. Dog weighing 2.300 kilos,
placed in a bell of 31 liters capacity. This bell (Fig. 27, C) is con-
nected by a rubber tube with thick walls to a huge receiver of sheet-
iron (B) in which the pressure has been brought to a 10 cm. A commu-
nication cock is opened, and the pressure falls immediately in the bell
to 12 cm. Immediately convulsive struggling, howls, foamy nasal hem-
orrhage; dead in 3 or 4 minutes. The lungs display ecchymoses which
do not disappear entirely after insufflation. Bronchi and trachea full
of bloody foam. Dark blood in the left cavities of the heart, very
dark blood on the right, without free gases.
Experiment CCCCXCIX. March 7. Large cat. Same experimental
procedure. Pressure is brought suddenly to 16 cm.; the animal rears up
almost immediately, struggles violently, yawns. At the end of 2 min-
utes, falls on its side, its tongue is dark; at 3 minutes, its pupils dilate,
shivers occur in the cutaneous muscles. Dead after 6 minutes. With-
drawn immediately, the animal, which is much swollen, collapses
when normal pressure is restored; no gas in the blood; dark blood
in the left heart, still more in the right heart; pulmonary veins red;
pulmonary ecchymoses.
Experiment D. March 15. Sparrow placed immediately by a sim-
ilar arrangement at 12 cm. pressure.
Struggling; very speedy death without true convulsions. No free
gases in the blood.
Experiment DI. June 18. Cat brought very rapidly to a pressure of
12 cm. Dies after a very rapid phase of convulsions. Lungs congested,
expand and become blanched when insufflated; the most congested
parts do not sink in water. No gas in the blood, examined with great
care.
Experiment DII. December 16. Two rats, placed in a bell of 2
liters, are brought as rapidly as possible (2 or 3 minutes) to a pres-
sure of 4.5 cm. They whirl, leap, die without true convulsions. With-
drawn immediately, and opened, one, A, in the air, the other, B, under
water: the hearts are still beating.
A. Blood examined by a magnifying-glass in the vessels ,then with
a microscope; no gas bubbles. Lungs very red in places, the red pieces
sink in water; they expand with insufflation.
B. No bubbles of gas can be seen escaping under water.
Experiment Dili. December 16. Rat killed by the same process, at
the same pressure; but kept for 10 minutes at 4.5 cm. No gas in the
blood, meticulous examination. Lungs adherent to the thorax, but
regain normal position when it is opened; reddish with small dots, all
parts float. The liver macerated with charcoal shows an enormous
quantity of sugar.
Sudden Changes in Pressure 857
When we compare these few data with those which have already
been reported and in which the decompression was made very sud-
denly, we see that the physical phenomena amount to very little,
even when the rapidity of the experiment should have increased
their importance. We have already spoken of the expansion of the
intestinal gases; when the vacuum is made suddenly, they do not
have time to escape, and must contribute a part, though small, to
the distress of the animal.
The pulmonary ecchymoses mean nothing, because we find
them in simple asphyxia, at normal pressure.
The pulmonary hemorrhages are not a constant fact; besides,
we see them occur in certain cases when the pressure was dimin-
ished slowly; it is therefore difficult to ascribe them to the sud-
denness of the decompression. I should rather think that the sud-
denness caused the strange appearance of the lungs of the dog in
Experiment CLXXX, "The lungs are red in large patches, sinking
in water, but expanding completely after insufflation."
This sort of fetal state seems to me to be due to a sort of suction
exercised in spots by the pressure of 7 cm. under which the animal
died.
We saw in the historical part of this work that former authors
attached much importance to this phenomenon which some of them
considered constant and extending to the whole lung. We have
reported on this point the observations of Musschenbroeck, Guideus,
and Veratti.
I myself have never seen the lungs of animals which were killed
by sudden decompression completely collapsed and heavier than
water in their entire mass. No doubt, as the ancients thought with-
out expressing themselves very clearly, when the weight of the air
is reduced to an amount below the strength of pulmonary elasticity,
the lung should collapse and a relative vacuum be made in the
pleura. But in the first place, this can happen only at pressures
lower than those at which animals die, because the pulmonary
elasticity of a dog, even in the condition of maximum inspiration,
even added to the negative pressure, does not go beyond 5 or 6
centimeters of mercury; this value is still less for smaller animals.
Finally, even supposing this empty space exists in the pleura, it is
evident that, when normal pressure is reestablished, the lungs will
be retracted to their original position, or the ribs would be broken
under the atmospheric pressure, as I formerly showed experi-
mentally; so that, even if this phenomenon occurred, there will be
no trace of it in the autopsy. For the pulmonary retraction to
858 Experiments
persist, either at the time of the sudden reestablishment of normal
pressure some vesicle must be broken, thus allowing the air to
penetrate the pleura; or after a long stay in the vacuum, gas or
liquids must be emitted, and it is probably for this reason that,
according to Veratti, the lungs are found in this state only when
the animals have remained some time under the pneumatic bell.
As to the escape of gas into the blood, to which former authors,
since Robert Boyle, have attributed such an important part, and
which F. Hoppe considered the principal cause of death, I must
say that I have found no free gases in the blood vessels when the
decompression was sudden any more than when it was more care-
fully controlled. And yet in vitro the liberation of the gases of the
blood begins under low decompression. For instance:
Experiment DIV. June 23. Two glass tubes are filled, one with
blood, defibrinated and settled, the other with water. Two hours
after, no gas bubble having escaped, we begin to lower the pressure,
stopping for 5 minutes every 10 centimeters.
At a pressure of 66 cm., no bubbles of gas escape; at 56 cm., noth-
ing; at 46 cm., bubbles appear on the walls of the tubes, both in the
water and in the blood; at 36 cm., the escape is abundant in both tubes.
An escape of gas must therefore take place in the blood vessels,
and first in the venous system where the pressure is less. But we
must note that the oxygen, granting that it leaves the blood, must
be immediately absorbed by the tissues, which are eager for it;
that the carbonic acid must pass through the pulmonary membranes
with the greatest ease; and that the escape is limited to the nitro-
gen, the proportion of which (from 1 to 2 per 100 volumes of blood)
is so slight. And, as the escape is very slow, it no doubt has time
to diffuse by way of the lungs. So that whether blood is drawn
from the living animal, as we succeeded in doing at a pressure of 17
centimeters (Experiment CLXXIX) or the blood of an animal
killed by sudden or slow decompression is examined, no free gases
are found in it. (See particularly Experiments DI, DII, and Dili,
in which search for gases was made with the greatest care.)
Sudden Changes in Pressure 859
Subchapter III
EFFECT OF SUDDEN DECREASE OF PRESSURE
BEGINNING WITH SEVERAL ATMOSPHERES
The subject of our researches here becomes much more interest-
ing. Indeed, it draws nearer the phenomena which we mentioned
in the historical part, in speaking of laborers who work on the
piers of bridges and of divers in suits.
I shall begin, as usual, by a detailed account of a certain number
of experiments. I report first those in which the decompression
was made without interruption and as rapidly as possible.
1. Decompression without Interruption.
A. Experiments Made on Sparrows.
Experiment DV. July 20. House sparrow. Seltzer water receiver.
Brought in 20 minutes to 8 atmospheres; left for 5 minutes under
pressure. Opened the large cock first, and made the decompression
in a few seconds. Struggled at the moment of decompression, then
did not appear sick, and survived.
Experiment DVI. August 3. House sparrow. Same apparatus.
Taken to 8 atmospheres at 12:30.
At 2 o'clock, sick; at 2:45, very sick. Took a sample of air which
contained 2.1% of CO.. Tension: 2.1 x 8 = 16.8.
Opened the large cock suddenly; the bird fell backward violently;
rose immediately: its rectal temperature was 25°, that of the outer
air being 20°, blood of the jugular veins very red; no gas seen. Re-
mained on its back and died in 10 minutes. At death, the venous
blood is dark; bubbles of gas seen in the jugulars.
Experiment DVII. May 1. House sparrow. Glass cylindrical re-
ceiver .
2:05, raised to 10 atmospheres; surrounded by papers wet in
potash solution so that the C02 is absorbed as it is produced.
At 3:40, the bird appears dead; the pressure is 9Vz atmospheres;
the air contains 14.1% of oxygen, and no doubt very little carbonic
acid. Decompression made rapidly. Almost immediately, the bird,
which raised its head at the moment when the cock was opened,
became very lively; bloody suffusions on the cranium. Survived.
Experiment DVIII. May 10. House sparrow. Cylindrical appara-
tus.
From 4:15 to 4:20, raised to 16 atmospheres. After 5 or 6 min-
utes shows quiverings with great distress, slight convulsions, etc.
characteristic of poisoning by oxygen, the tension of which was
16 x 20.9 = 334. At 4:30, decompression made in 1 minute; did not
860 Experiments
seem to suffer from the decompression; no gas in the jugulars, in
which the blood was very red. Enormous bloody suffusions on the
cranium. Rectal temperature 35°. At 4:35, great convulsions, died.
Rectal temperature 34°. The blood was very red in the left heart,
without gas. In the right heart and the jugulars, it was dark with
gas in very small bubbles; these bubbles were present in the portal
system.
Experiment DIX. October 27. Sparrow (cylindrical receiver).
Taken to 8 atmospheres. Decompression made in 5 seconds. Taken
from the apparatus, did not seem at all inconvenienced.
Experiment DX. October 27. Sparrow (cylindrical receiver).
Taken to 10 atmospheres. Decompression made in 5 seconds. No
symptom, survived.
Experiment DXI. October 27. Sparrow (cylindrical receiver.)
Taken to 12 atmospheres. During this time remained motionless
at the bottom of the apparatus. When sudden decompression was
made, darted to the top of the cylinder, then fell back. Was dead
before being taken from the apparatus. Air in quantity in the jugulars
and the right heart.
Experiment DXII. October 27. Sparrow (cylindrical receiver).
Taken to 14 atmospheres. Sudden decompression; died in a few
minutes. Air in quantity in the jugulars and the right heart.
Experiment DXIII. October 27. Sparrow (cylindrical receiver.)
Taken to 14 atmospheres. Sudden decompression, without symp-
toms. Found dead the next day.
Experiment DXIV. October 27. Sparrow; cylindrical apparatus.
Taken to 15 atmospheres, and suddenly decompressed immediately.
Removed from the apparatus, could not walk, flapped its wings, had
convulsions, and soon died. Air in quantity in the jugular veins and
the right heart.
Experiment DXV. June 29. Two sparrows were taken in one hour
to a pressure of 7 atmospheres under a current of air maintained by
the large sheet-iron cylinder. At this moment, the rubber communi-
cation tube burst; the decompression was instantaneous. The two
birds died in a quarter of an hour.
We must add to these experiments made on sparrows the results
of a great number of others already reported with another purpose
in the subchapter of Chapter I. We shall return to them later.
For the moment I set aside the discussion which these experi-
ments deserve and report those made on mammals.
First, rats, for which we generally used the small glass appa-
ratuses.
Sudden Changes in Pressure 861
B. Experiments Made on Rats.
Experiment DXVI. August 9, 1871. Rat. Seltzer water receiver.
9:25, placed at 7 atmospheres. 10:10, pressure fell to 6V2; the
animal is rolled up in a ball, with hair bristling; respiratory rate 75.
1 open the large cock suddenly; the animal arouses immediately, and
does not seem to be in pain.
Experiment DXVII. August 10. Same animal, same apparatus.
4:10, placed at 6 atmospheres. 5:25, respirations difficult, dicrotic;
the animal is lying curled up on the bottom of the vessel. Took sample
of air, which contained 5.2% of CO,. Tension: 5.2 x 6 = 31.2. The
pressure then falls to 5V2. I open the large cock suddenly. The animal
almost immediately stands up on his feet, and seems quite well.
Experiment DXVI II. August 12. Same animal, same apparatus.
At 4:15, placed at 6V2 atmospheres. The apparatus leaks; at 6
o'clock, the pressure is 4V2 atmospheres; the animal is very sick. I
take a sample of air, which contains 6.1% of CO,.
Tension: 6.1 x 4.5 = 27.4. I open the cock wide; the rat does
not recover immediately, but he is well the next day.
All the experiments reported next were made in the large
cylinder of sheet-iron pictured in Figure 33. The large cock which
is opened suddenly is the one lettered c:
Experiment DXIX. May 24. Two rats in the large cylindrical
apparatus (experiment made before the Committee of the Institute).
They are taken to 8V2 atmospheres; the decompression is made in
2 minutes. The rats run about when taken from the apparatus; a
few minutes after, they become paralyzed and die. Gas is found in
the whole venous system.
C. Experiments Made on Rabbits.
Experiment DXX. June 22. Rabbit.
Taken to 8 atmospheres. Decompressed in 3 minutes. Ears bright
red; no symptom either immediate or later.
Experiment DXXI. November 7. Two rabbits.
Taken to 7 atmospheres. Decompressed in 2V2 minutes. No
symptoms.
Experiment DXXII. November 10. Same animals.
Taken to BVs atmospheres; decompressed in 2V4 minutes.
No symptom either immediate or delayed.
Experiment DXXIII. November 15. Rabbit.
Taken to 6V2 atmospheres. Decompressed in 412 minutes. No
effect.
D. Experiments Made on Cats.
Experiment DXXIV. May 23. Male cat, extraordinarily vigorous
and wild. Taken to 10 atmospheres. Sudden decompression. Leaps
862 Experiments
out of the apparatus, apparently well, and hides under a piece of
furniture. Half an hour later, it is found there paraplegic. The hind
legs are stiff, with the claws extruded; they are sensitive, as is the
tail, but are no longer under voluntary control. Bloody urine con-
taining spermatozoa is drawn from the animal. The anal sphincter
is contracted.
May 24. Same condition; except that the tail and the hindquar-
ters are entirely without sensitivity and are relaxed. By pinching a
foot, very distinct reflex movements are obtained, which, however, do
not pass from one member to the other.
The bladder is enormously distended by urine containing much
blood.
The anal and vesical sphincters are strongly contracted.
The animal mews faintly; it is very weak, drags itself along with
difficulty by its front feet; rectal temperature 33°.
Killed by section of the medulla.
Vesical mucous membrane shows hemorrhages in dots; no blood
in the ureters or in the pelvis of the kidneys. Nothing unusual in the
lungs, heart, or brain. No hemorrhage or congestion of the spinal
cord; but on the level of the last two thoracic and the first two lumbar
vertebrae there exists a softening of the spinal cord so advanced that
at certain points (last thoracic), the spinal marrow runs like cream.
The microscope shows the nervous elements intact, without a trace
of bloody effusion.
Experiment DXXV. June 17. Cat.
From 12:20 to 1:30, taken to 10 atmospheres. At 1:39, decom-
pressed suddenly in 3 minutes. When taken from the apparatus, runs
in all directions as if panic-stricken. At 1:48, begins to be paralyzed
in the hindquarters; at 1:50, lies on its side, unable to rise. Pupils
contracted, the left more than the right; rectal temperature 39.5°;
pulse 140, regular; respiratory rate 36, difficult, irregular. Motility
and sensitivity completely gone in the hindquarters and the tail. 2
o'clock. No respirations; action of the heart still regular.
Immediate autopsy. Auricles still contract; on pricking the right
auricle, frothy blood containing air issues; the left auricle, on the
contrary, contains no air. On exposing the spinal marrow, we see in
veins of the meninges a great quantity of small air bubbles; these
bubbles also issue from the vessels of the spinal marrow when it is
cross-sectioned. No sign of hemorrhage or congestion in the cord.
Experiment DXXVI. June 22. Cat of Experiment DLXVII (placed
with the rabbit of DXX). 3:20, began the compression. At 4 o'clock,
5V2 atmospheres; the motor stops. Began again at 4:20; at 4:45, 8
atmospheres. Current of air maintained under pressure.
At 4:50, decompression in 3 minutes. The cat leaps out of the
apparatus and flees. At 5 o'clock, it is seized by an attack of con-
vulsions, with violent struggling which lasts about 5 minutes. During
these disordered and indescribable movements, the hindquarters pro-
gressively stiffen and become motionless, while the forequarters and
the head are prey to the strangest contortions. Repeatedly the animal,
Sudden Changes in Pressure 863
which is curled up, turns backwards and bites his hind legs and
thighs with a kind of fury.
After 5 minutes, relatively calm; the left pupil dilated inordinately;
almost complete paraplegia. Defecation by intestinal contraction, the
anal sphincter not being paralyzed. Urination; no blood or sperm.
5:30. I show the animal to the Society of Biology; the paraplegia is
complete as to movement and sensitivity. The pupils are in their
normal state. 5:45. Apparent improvement; the left leg is sensitive,
and the animal moves it a little, and when I support it, even leans on
it a little; nothing in the right leg. 6:15. The right leg recovers a
little in its turn; the tail begins to be sensitive.
June 23. The paraplegia has become complete again, and has even
spread a little into the lower dorsal region. The following days, paral-
ysis still more complete and extending a little higher. Dies June 26,
the bladder distended; it could not be made to urinate; it ate.
Autopsy. All the spinal marrow is softened a little; it is diffluent
below the cervical enlargement. At this precise point, it is a little
yellowish, and contains a little altered blood and some granular bodies
in the process of formation; the veins of the meninges contain a mix-
ture of air and blood; air escapes from the vessels of the spinal cord.
Sugar in the liver, a little in the urine, which also contains a little
blood.
E. Experiments Made on Dogs.
Experiment DXXVII. May 17. Dog weighing 4 kilos. Pressure
raised to 4 atmospheres. After about Va of an hour, opened the large
cock suddenly; decompression in less than 2 minutes. The animal is
in good shape.
Experiment DXXVIII. June 18. Small dog. Taken in one hour to
10 atmospheres; stays there about 1 hour; decompressed in 3 minutes.
The animal cannot get out of the apparatus; there are no other move-
ments than those of respiration; constant cries of pain.
Placed on the autopsy table, gas is observed in the jugular which
has been exposed. Through the jugular a cannula is passed into the
right heart, from which is extracted 33.9 cc. of gas containing 20.8%
of CO. and 79.2% of nitrogen, with some traces of oxygen. The right
heart and the veins are full of gas and frothy blood; the same thing
is true of the veins of the pia-mater and the choroid plexuses. Stom-
ach much distended by gases.
Experiment DXX1X. July 9. Dog weighing 12 kilos.
1:45: taken to 5 atmospheres; left 30 minutes under a current of
air. Decompressed in 2 minutes. No immediate or delayed symptom.
Experiment DXXX. July 13. Dog which has lost much blood.
Taken to 6 atmospheres and decompressed in 2 minutes. The animal
drags its hind legs and walks on its nails; after an hour, walks better,
but lies down again as soon as we stop stimulating him. Better {he
next day.
864 Experiments
Experiment DXXXI. July 17. Dog of Experiment DXXIX and
Experiment DLXXI (slow decompression).
From 1:36 to 2 o'clock, taken to 6 atmospheres; left 30 min.
Decompressed in 2 minutes; comes out in good condition, shakes
himself, and walks very well. No symptom.
Experiment DXXXII. July 22. Dog.
From 5:30 to 6:10 taken to 6V2 atmospheres. I then draw blood
from which no free gases escape in the syringe. However this blood
contains 7.7% of nitrogen. At 6:40, reached 8V2 atmospheres; decom-
pressed in 3 minutes. At 6:50, I draw blood from the carotid; this
blood contains 2% of nitrogen.
The animal has remained fastened on the operating table; while
sewing up the wound in the neck, I see bubbles of air in the jugular;
it begins then to take deep breaths, which end in death at 7:15. No
gas is found in the blood of the right or left heart; but there are nu-
merous bubbles in all the little veins of the general and the portal
systems. The stomach is enormously distended; 550 cc. of gas is drawn
from it; the intestine contains much gaseous froth and is swollen
with it.
Experiment DXXXI1I. July 24. Dog of Experiment DXXXI.
From 3:30 to 3:55, taken to 6 atmospheres; left 2 hours under a
current of air. Decompressed in 2 minutes, no symptom.
Experiment DXXX1V. July 25. Dog of preceding experiment.
From 2 o'clock to 2:45, taken to 7 atmospheres.
Decompressed immediately in 2 minutes: jumps alone from the
top of the apparatus. Five minutes after, falls on its side, its hind-
quarters paralyzed; sensitivity much dulled. The front feet are in
forced extension and quiver at each breath.
July 27. Complete paraplegia of movement; muscles relaxed;
tail and feet insensible, but with reflex movements of the tail. The
anal sphincter is relaxed, but the introduction of a thermometer pro-
vokes violent reflex movements; temperature 39.5°. Bladder para-
lyzed; when the belly is pressed, the urine issues in jerky spurts; it
overflows regularly; no sugar.
August 1. The animal has remained lying on its right side; the
paralysis has made ascending progress; the ribs are motionless, and
the respiration is purely diaphragmatic; we then see clearly the lifting
of the lower ribs by the diaphragm.
On pinching the right hind foot, it draws away, as does the tail:
no movement in the left hind foot. The left sciatic, when exposed
and pinched vigorously, causes some slight movements in the flexor
muscles of the leg, but the animal feels nothing. The right sciatic
gives marked movements, and the animal shows pain when it is
pinched. The muscles tested by electricity require for contraction a
current a little stronger on the left than on the right, which is no
doubt due to the different action of the nerves. The toes of the hind
feet, when taken in the hands, are warmer than the toes of the front
feet; the latter are sensitive and are drawn away when pinched. The
anal sphincter contracts convulsively when touched; the rectal temper-
Sudden Changes in Pressure 865
ature is 38°. The urine issues when the right sciatic nerve is stimu-
lated: no sugar. I kill the animal, which is very sick, by opening
the thorax.
The left sciatic nerve is reddish, its vessels are bloodshot; in most
of its fibers the myelin is a little turbid and is beginning to separate.
The right sciatic nerve is intact.
The spinal cord is softened in the region of the lumbar enlarge-
ment. Transverse sections show the following changes. Below the
enlargement, red dots in the gray matter; in the upper part of the
enlargement, where section is possible, we find complete suffusion of
the left posterior horn of the gray matter and suffusion in parts of
the horn on the right side; the antero-lateral and posterior columns
on the left are of a very marked yellowish-gray; all of it is very soft.
Below the dorsal region, uniformly red appearance of all the gray
matter, which is less soft, with coloration spreading into the posterior
white matter, especially on the left; yellowish gray softening of the
left antero-lateral column and the posterior column.
The alteration lessens as it goes upward and ceases above the
brachial enlargement; the cord there is firm, but a little suffused.
Experiment DXXXV. August 3. Dog.
At 8 atmospheres, the little apparatus, which supports the cannula
for drawing blood (Fig. 34, E), is violently thrown forward: the
pressure falls in 3 or 4 minutes.
The dog comes out, runs a few steps, then falls and dies rapidly.
Gas in abundance in the right heart, but not in the left heart.
Experiment DXXXVI. August 5. Pregnant bitch taken to 9V4
atmospheres, bled of 375 cc. of blood (See Exp. CLXXXIV)1; decom-
pressed rapidly: takes a few breaths and dies.
Both sides of the heart are full of gases almost completely free:
the stomach contains little gas.
The hearts of the foetuses and their veins contain both gas and
a very dark blood. In the allantoid liquid abundant bubbles are float-
ing; the placenta is all torn by the gases; no gas in the amnion.
Experiment DXXXV II. October 16. Dog which has already served
for Experiments DLXXVII and DLXXVIII (10 atmospheres, slow
decompression). From 1:10 to 1:45, taken to 7 atmospheres, decom-
pressed at 1:55 in 2 Vz minutes.
Taken from the apparatus, is lively and seems to feel no painful
symptom. 7>Vz minutes after the decompression, raises its right front
foot and seems to be in pain. After 5 minutes, struggles, wavers in
its hindquarters, has an almost sudden erection. After 7 minutes,
enormous convulsive stiffening of the hindquarters, which one can
hardly bend. The tail moves and the front legs are not affected.
The animal is recompressed to 7 atmospheres and decompressed
very slowly. (See Exp. DLXXXVIII.) Dies the next day.
Experiment DXXXV III. October 18. Dog.
From 2:25 to 3:10 compressed to 7 atmospheres, and left 7 min-
utes. Decompressed as rapidly as possible, in 2 minutes, from 3:17 to
3:19. Withdrawn from the apparatus, comes, goes, fawns; but at 3:21
) Experiments
is seized by paralysis of the hindquarters; he soon remains lying
down, and his sufferings are shown by howls.
Taken to 7 atmospheres again, and then to an extremely slow
decompression. (See Exp. DLXXXVII.) Dies in the evening.
Experiment DXXXIX. October 20. Dog.
Subjected to 3% atmospheres. Arterial blood drawn under mer-
cury in a test tube. Very small bubbles of gas are plainly escaping,
and collecting at the upper part of the tube.
Decompressed in 1 minute, shows no symptom; the heart sounds
are normal.
Experiment DXL. October 23. Same animal taken to 4% atmos-
pheres, and left 10 minutes. Decompressed in 1V4 minutes, expe-
riences no symptoms immediate or delayed.
Experiment DXLI. October 25. Same animal taken to 5 atmos-
pheres; left 10 minutes and decompressed in 1% minutes. Still no
symptom.
Experiment DXLII. October 31. Dog.
Taken to 7% atmospheres. Decompressed in 1V4 minutes. Taken
out at 2:07, without immediate symptoms.
At 2:15, is found weak, staggering, has vomited several times. At
2:35, enormous gurglings heard in the heart, and the animal dies
suddenly.
Gas in the heart and the whole venous system, even the portal
vein. Nothing in the left heart.
Experiment DXLIII. October 31. Dog.
Placed beside the former; has no immediate symptom. But at
2:15 is found lying on its side motionless; respiration is difficult,
whistling, as if the animal were going to die soon. There are gurglings
in the heart.
He is made to inhale oxygen (See conclusion, Exp. DLXXXIX).
He dies during the night.
Experiment DXLIV. November 12. Dog.
Taken to 7x/4 atmospheres. Decompressed in 2 minutes. Dies in
about 25 minutes. Free gas in all the little veins; right heart full of
foam; bubbles less numerous in the left heart.
Experiment DXLV. November 12. Dog.
Placed beside the former. Seized by symptoms of paralysis and
dies after about 1% hours, after he has been given oxygen. (See
Exp. DXC.)
Experiment DXLVI. November 15. Dog.
Taken to 6V2 atmospheres; decompressed in 4 ¥2 minutes. No
symptom; no gas in the blood of the jugular vein, which I examined
with the microscope to make more certain.
Experiment DXLVII. November 25. Bitch.
From 2:25 to 3 o'clock taken to 7Y2 atmospheres.
At 3:14, decompressed in 2 V2 minutes.
Sudden Changes in Pressure 867
At 3:23, is paralyzed in the hindquarters, then falls; in a few
minutes, respiration stops, and the heart beats only 20 times per
minute; loud gurgles heard in the heart; eye lacks sensitivity, pupils
dilated.
Oxygen administered, but the animal dies at 3:35. (See Exp
DXCI.)
Experiment DXLVIII. November 27. Very small poodle.
Raised to 7 atmospheres from 3 o'clock to 3:53.
Decompressed in 2J/4 minutes.
Taken from the apparatus, seems gay for a few minutes, then,
at 4:10, begins to limp, is paralyzed in the hindquarters, and sud-
denly falls on its side. Very loud gurgles in the heart.
Oxygen administered, but the animal dies at 4:27. (See Exp.
DXCII.)
Experiment DXLIX. December 6. Short-haired dog, very lively.
Put under pressure from 2:30 to 4:20 and taken to 7% atmos-
pheres.
At 4:20, decompression in 2 minutes.
Leaves the apparatus. At the end of 10 to 15 minutes, is paralyzed
in the hindquarters, and seems quite ill with perhaps gurgling in
the heart (?).
Then recovers a little, but yet cannot stand on its hind legs, which
have retained sensitivity.
December 7. Is still paraplegic and can hardly stand on its front
legs. Reflex movements, reflex sensitivity in the hind legs, which are
warmer than the front legs.
December 11. Scab on the left shoulder, on which it is lying; odor
of urine; hyperesthesia in the front feet; dying.
Experiment DL. December 6. Spaniel, placed beside the preced-
ing animal.
Remained in the apparatus from which it was removed para-
plegic, with very loud gurgles in the heart. It was given inhalations
of oxygen. (See the continuation of its history, Experiment DXCIII.)
Experiment DLL December 22. Dog.
Taken to 8V2 atmospheres. Decompressed in 2V2 minutes.
Taken from the apparatus, is already limp, and dies in 5 or 6
minutes. Air in great quantity in the right heart and the veins. Some
bubbles in the left heart. Gas in abundance in all the vessels of the
lower region of the spinal cord.
Experiment DLII. January 16. Bitch weighing 6.5 kilos, in bad
state generally.
Taken to 71/2 atmospheres, then decompressed suddenly. No
symptom immediate or delayed.
Experiment DLIIL January 23. Same animal.
Taken again to IV2 atmospheres and decompressed suddenly.
About 10 minutes afterwards, bites its hindquarters, as if it felt keen
pains there; it then seems to have some trouble in locomotion, but
this disappears quickly.
868 Experiments
Experiment DLIV. January 25. Same animal.
Taken to 8 atmospheres, and decompressed suddenly. No ap-
parent effect.
Experiment DLV. January 29. Same animal.
Taken to 8V2 atmospheres, and decompressed suddenly.
Experiences a little irregularity and difficulty in the hindquar-
ters, but seems very gay, with no uneasiness; no gurgles in the heart;
no gas observed in the jugular, which has been exposed.
Experiment DLV I. February 11. Same animal.
Compressed to 8 atmospheres and left under pressure 5 minutes,
then decompressed in exactly 3 minutes.
At the fifth minute, after the beginning of the decompression,
blood is drawn from the carotid; no gas found in it.
At the tenth minute, blood drawn from the right heart with a
cannula: no gas there either.
No symptom.
Experiment DLVII. February 12. Sickly dog, very thin, weigh-
ing 8 kilos.
From 4:30 to 5:32, taken to 8 atmospheres; decompressed in 3
minutes.
Placed on the floor, does not seem at all uneasy, and walks.
At 5:42, the hindquarters become stiff and motionless.
At 5:55, the forequarters are similarly affected; great respiratory
distress.
Dies at 6:05. Air in the veins.
Experiment DLVIII. February 27. Poodle weighing 7 kilos.
Placed in the apparatus at 8 o'clock in the morning, at 9:30 is
at 10 atmospheres; the pump is stopped.
At 10 o'clock, the pressure is only 9%.
At 10:30, I look at the animal; it is well, and puts its nose against
the porthole; the pressure is 9 ¥2 atmospheres.
I enter the laboratory again, and immediately a violent explosion
is heard. The porthole glass has burst and its fragments had enough
force to cut a lead water pipe one meter away; the apparatus was
lifted, torn from its supports by the recoil, and overthrown.
I take the animal out with great difficulty, for it has become
cylindrical, and is hard to pull through the door. General sub-
cutaneous intra- and submuscular emphysema. I open the belly; the
gas which distends it escapes whistling.
The right heart is full of gas, as are all the veins, the pulmonary
artery, and the pulmonary veins. But there is none in the left
auricle or the aorta. There is gas in the anterior chamber of the eye,
and in the cerebro-spinal liquid. The nerve fibres of the spinal cord
are dissociated by bubbles of gas, which are not in the vessels.
There is no hemorrhage in the brain or the cord; the lungs are
a little congested: no blood in the trachea.
I extract 50 cc. of gas from the right heart (there is much more
of it) taking all precautions to prevent entrance of air. This gas con-
tains per 100 parts: O, 1.9; CO, 15.1; N 83.0.
Sudden Changes in Pressure 869
Experiment DLIX. May 6. Dog weighing 11 kilos.
From 1 o'clock to 1:58, compressed to 7% atmospheres.
I maintain a current of air under pressure until 7 o'clock, when
I make the decompression in 3 minutes.
On leaving the apparatus, the animal staggers, then stops, falls,
and dies.
There are abundant bubbles of air in the right heart and the
veins, tiny bubbles in the left heart.
No gas in the subcutaneous cellular tissue, except in the hollows
of the armpits; gas is also found in small bubbles in the tissue of the
epiploon.
The intestines do not appear more swollen than under ordinary
conditions.
Experiment DLX. June 3. Bitch of Experiments DLII to DLVI.
Well fed, has become fat and very well.
From 3:05 to 4:05 was taken to 8 atmospheres and decompressed
immediately in 1% minutes.
Taken from the apparatus, it runs everywhere, apparently gay,
and wagging its tail.
But after 3 or 4 minutes, utters pitiful howls and tries to bite its
hindquarters, which begin to be paralyzed.
Auscultation of the heart shows considerable gurgling on the
right, but not on the left.
Two or three minutes later, the howls cease, the paralysis, both
of sensibility and movement, is complete.
It increases, affects the whole body, with rigors in the legs and
neck. The respiration, which for a long time has been merely
diaphragmatic, becomes very difficult; the heart slows down and the
animal dies about 4:30.
I find gas in the general venous system and the portal vein, but
not in the arteries.
There is emphysema in the subcutaneous tissue of the armpits;
there are innumerable little bubbles in the fatty tissue under the
muscles of the thorax, and in the sub-aponeurotic layer all along the
back, in the epiploon, the mediastinum, the furrow of the heart, and
the fatty tissue of the medullary canal.
Index of air in the vessels of the medullary and cerebral pia-
mater: nothing in the velum interpositum, or the cerebro-spinal
liquid.
No blood effusion in the brain; rather large dotting on the
spinal cord. Lungs healthy, without congestion or emphysema; con-
gestion of the spleen; little suffusions of the great epiploon.
Experiment DLXI. July 21. Dog weighing 6.5 kilos.
From 2:30 to 4 o'clock, taken to 8 atmospheres.
At 4:10, decompressed in l1/* minutes.
Dies at 4:22, with air in quantity in the whole venous system;
small bubbles in the left heart.
Lungs blood-shot, edematous.
870 Experiments
Experiment DLXII. May 24. Large spaniel.
(Experiment made before the Committee of the Academy of
Sciences.)
Compression raised to 8V2 atmospheres, and decompression made
in 2 minutes.
The dog appears gay and runs about wagging his tail. After a
few minutes, he sits down and becomes sad. Some minutes later, he
falters on his front legs and falls down.
Gurgles can be heard in the right heart.
The animal seems to be in great pain and bites violently at what-
ever is held out to him. He soon dies.
Gas in fine bubbles in the whole venous system; none in the
arteries.
Experiment DLXIII. June 4. Young dog in good health, weigh-
ing 4.500 kilos.
The jugular vein is exposed without being opened; the animal,
fastened on the operating board, is carried to the compression ap-
paratus, and rapidly taken to 6 atmospheres, and this pressure is
maintained under a current of air for 3V2 hours. It howls a great deal.
Decompression in 20 seconds. The animal is taken from the
cylinder and unfastened. Complete paralysis of movement and of
sensibility in the four legs; rapid pulse, accelerated respiration; no
howls.
Put back immediately on the operating table; 50 cc. of blood are
drawn from the peripheral end of the jugular; no gas to be seen;
blood is slowly ejected under water; no gas bubbles. A cannula is
inserted into the right auricle; 50 cc. of blood is drawn and treated
in the same way; no bubbles.
The dog is attacked by diarrhea and involuntary urination.
It dies during the night.
The autopsy shows the presence of large bubbles of gas in the
venous system (vena cava, azygos vein, mesenteric veins). Much is
found in certain lobes of the liver and in the kidneys, a little in the
spinal cord, no trace of it in the brain, the meninges, or the muscles.
Experiment DLXIV. June 12. Young white dog of small size, in
very good health. Placed in the large cylinder; brought rapidly to
5 ¥2 atmospheres of pressure. Maintained under this pressure with a
current of air for 4 hours.
The animal seems very quiet during all this time.
Decompressed in 20 seconds.
When taken from the apparatus, it runs away, and we have great
difficulty in catching it. When the right jugular and femoral veins
are exposed, we see passing a long series of gas bubbles which keep
growing larger.
After a few minutes, by means of a syringe, we draw from the
peripheral end of the jugular a certain quantity of blood which is
gently ejected under water: immediately numerous bubbles are seen
escaping to the surface.
Dog, kept under observation for several days, shows no delayed
symptom.
Sudden Changes in Pressure 871
I summarize in the following table the principal results fur-
nished by the experiments just read. I have listed them here by
increasing order of pressures.
I have included in this table the results of experiments in which
I attempted to save the animals, either by recompressing them or
by administering oxygen. (See Subchapter IV.)
Table XVIII
Duration
Gv
Duration
Experiment
of
a, 2
of
number
compression
Decompression
Sparrows
DXV
slow compr.
1
1 7
instan-
taneous
1
| Dead in a quarter of an hour.
I Two animals.
DV
5 min.
8
a few sec.
1 No symptoms.
DIX
2 min.
8
id.
1 id.
DVI
2 hours
8
1
id.
I Died in 10 min. Gas in the
1 blood.
DVII
1 h. 35 min.
9V2
id.
I No symptoms.
DX
a few min.
10
id.
id.
DXI
id.
12
1
id.
| Died almost immed. Gas in
| abundance.
DXII
id.
14
id.
| Died in few minutes. Gas
| in abundance.
DXIII |
id.
14 |
1
id.
| No immediate symptoms.
| Dead next day.
DXIV |
1
id.
15 I
1
id.
| Died quickly. Gas in abun-
| dance.
DVIII
1
5 min.
16
1
1
id
| Died in a few minutes. Gas:
| convulsions from oxygen had
| begun.
Rats
1
DXVII |
iy4 h.
5% |
a few sec.
1
| No symptoms.
DXVIII
1% h.
6V2|
| id.
DXVI |
% h.
6% I
a few sec.
I No symptoms.
DXIX
1
1
|
8V2 |
I
1
2 min.
| Two animals. Dead in a few
| minutes. Gas in the blood.
1
Rabbits
i
DXXIII
1
1% h.
6V2 |
4V2 min.
| No symptoms.
DXXI
a few min. |
7
2 to 3 min.
| Two animals.
DXX |
5 min.
8
id.
I id.
DXXII |
!
|
1
8% I
1
id.
| Two animals.
1
872
Experiments
Table XVIII— Continued
c£
Experiment
Duration
Duration
of
fn
of
Condition of animal
compression
3 §•
$ o
Decompression
Cats
DXXVI
5 min.
8
2 to 3 min
!
Paraplegia, dies in 4 days;
medullary softening. Exp.
1 made at the same time
! as Exp. DXX.
DXXV
9 min.
10
id.
I Dies in 15 min. Gas in the
I blood.
DXXIV
10
id.
I Killed next day. Medullary
! softening.
1
Dogs
DXXXIX
DXXVII
DXL
DXXIX
DXLI
DLXIV
DXXXI
DXXXIII
DXXX
DLXIII
DXLVI
DXXXIV
DXXXVIII
DXXXVII
DXLVII
DXL VIII
15 min.
30 min.
4 hours
30 min.
2 hours
a few min.
3 h. 30 min.
a few min.
id.
7 min.
10 min.
15 min.
a few min.
I I
3 Vz I 1 to 2 min. | No symptom, yet tiny bubbles
I of gas escape from the blood.
4 ! 2 to 3 min. | No symptoms.
4V2 I id. | id. Same animal as in
| Exp. DXXXIX.
5 I id. |id.
5 id. | id. Same animal as in
I Exp. DXL.
5V2 | 20 sec. | Gas in the veins; no
i symptoms.
6 id. I id. Same dog as in
I Exp. DXXIX.
6 id. [ id. Same dog as in
! Exp. DXXXI.
6 id. I Drags hind-quarters a little.
! Recovers.
6 I 20 sec. I Immediate paralysis; no gas.
I Dies; gas everywhere.
6V2 I 4V2 min. | No symptoms. No gas in
! jugular blood.
7 I 2 min. | Paraplegia, medullary sof-
| tening. Dies in a week. Same
I dog as in Exp. DXXXIII.
I Paraplegia; recompressed and
I decompressed slowly. Dies in
I the evening.
(Paraplegia; recompressed and
I decompressed slowly; dies
I next day. No gas in blood.
! Small bloody spots in spinal
! marrow.
I Paralyzed, much gas in heart;
I dying. Oxygen inhaled; res-
I piration restored; accident;
I death.
! 2V4 min. | Paralyzed; oxygen inhaled;
I dies.
7 I 2 min.
I
7 I 2V2 min.
I
I
7V2 I 2 min.
I
I
Sudden Changes in Pressure
Table XVIII— Continued
873
Experiment
number
Duration
of
compression
Ko
<u e
Duration
of
Decompression
Condition of animal
DXLIV
DXLIII
DXLIV
DXLV
DXLIX i
|
DL
I
I
I
DLII
DXXXV
DLVII
DLI
DLIII
DLIV
DLVI
DLV
DXXXII
7V4 I IVa min.
I
I IV4 I IV4 min.
I 7y4 I 2 min.
I
7V4 j 2 min.
I
I
I
I
I IV2 i 2 min.
I !
I 2V2 I 2 min.
!
I
7V2 I 2 min.
7% I 3 min.
8 3 or 4
i
8 I 3 min.
I
8V4 I 3 min.
8V2 i 2V2 min.
IV2 I 2 min.
8 2 min.
8 2 min.
•2 2 min.
8V2 I 3 min.
I
I Paralyzed, dies after 25 min.
i Gas in heart.
i Paralyzed, inhales oxygen,
respiration resumed, gurgles
disappear. Remains para-
lyzed, dies; no air in blood
vessels.
Dies in 25 min. Gas in right
and left heart.
Paralyzed, dying; breathes
oxygen; better, gurgles disap-
pear; moves, uneasy, dies
after 1% hours; no gas in
blood vessels.
Slightly sick, recovers,
slightly paraplegic.
Paralyzed; gurgles. Oxygen.
Gas disappears, animal sur-
vives, paraplegic. Dying on
third day.
No symptoms.
Oxygen inhalations. The be-
ginning paralysis is checked,
but dog remains paralyzed
several days.
Dies quickly. Gas in right
heart.
Dies in quarter of an hour.
Gas in veins.
Oxygen inhalations. Paraple-
gia, no gas in heart; better;
dies during night.
Dies quickly. Air everywhere.
Animal of Exp. DLII. Slight
locomotor and sensory dis-
turbances.
1 Same animaL Nothing.
I Same animal. Nothing. No
! gas in blood.
I Same animal. Slight loco-
I motor disturbances. No gas
in the blood.
Rapid death (25 min.). No
I gas in heart; gas in all small
I veins, portal vein, and ves-
| sels of the medulla; 550 cc.
I of gas in the stomach.
874
Experiments
Table XVIII— Concluded
Experiment
number
Duration
of
compression
Duration
of
Decompression
DXXXVI |
DXXVIII
id.
| 9V4 I 3 min
10 | 3 min
Condition of animal
DLVIII | 1 hour | 9V2
DLIX
DLX
DLXII
DLXI
5 hours
a few min.
id.
10 min.
Explosion
Blood drawn at 3 atm. re-
leased free gases. Died after
a few breaths. Gas every-
where. She is pregnant; gas
in blood of foetuses and al-
| lantois; placenta torn.
| 34 cc. of gas drawn from
| right heart (CO, 20.8; N 79.2;
| 02 traces) . Gas in vessels of
| pia mater.
| Instantaneous death. Huge
subcutaneous and submuscu-
lar emphysema, gas in belly,
in epiploon, the anterior
chamber of the eye, the cere-
brospinal liquid, the spinal
cord. No hemorrhage in spinal
cord, brain or lungs. No gas
in left heart. Right heart full
of gas (CG. 15.2; N. 82.8; G
2.0).
Rapid death; subcutaneous
emphysema. Gas all through
blood.
1 m. 45 sec. | Animal of Exp. DLII to DLVI.
I Dies. Gas in venous system;
I subcutaneous emphysema.
| Dies. Gas in veins.
| Dies in 12 min. Gas in veins
| and left heart.
I
7% I 3 min.
8V2 I 2 min.
8 I IV4 min.
2. Slow Decompression or Decompression in Stages.
The preceding data furnish ample material for a fairly complete
account of the curious phenomena due to sudden decompression
and for an explanation of them. However, there is such variety in
the details that it seems best to report in addition a certain number
of experiments of the same type, in which, however, the decom-
pression was made more slowly, for the purpose of finding out the
precautions that must be taken if the decompression is to be
harmless.
Here are these experiments:
Experiment DLXV. June 20. Guinea pig. From 2:45 to 3:50
brought to 10 atmospheres; I establish a current of air under pressure.
Sudden Changes in Pressure 875
At 4:04, opened the cock wide; in 1 minute, the pressure falls to
5 atmospheres; I then keep the cock open a little; the pressure is
down to normal at 4:30.
Opened the apparatus: the guinea pig seems in good condition;
but at 4:40, he struggles, rolls up, is paralyzed in ascending progress,
the respiration is disturbed, and stops at 4:45.
Gas in abundance in the right heart, in the veins of the legs and
the arteries. No gas in the left heart, the pulmonary and coronary
veins, and the portal system.
No gaseous distention of the stomach and the intestines.
Experiment DLXVI. June 20. Cat, placed beside the guinea pig
of the preceding experiment.
Taken to 10 atmospheres. Dropped in 1 minute to 5 atmospheres,
then in 25 minutes to normal pressure.
No immediate or delayed symptom.
Experiment DLXVII. June 29. Cat and rabbit brought in 1V2
hours to 10 atmospheres. Pressure maintained under a current of air
for 5 hours.
Decompression in 2 hours.
They are taken out all wet, trembling (the cat was trembling in
the apparatus in the compressed air), they did not cry out; no
paralysis; they recover rapidly and survive.
The temperature of the cat has fallen from 39.5° to 34.3°; that
of the rabbit from 39.6° to 36.7°.
Experiment DLXVIII. July 2. Rabbit of Experiment DXX. From
2:50 to 3:55, raised to 10 atmospheres; current of air for 30 minutes.
The decompression is begun at 4:27; it is made with calculated
slowness, watch in hand, at the rate of about 1 atmosphere per 2
minutes; it is finished at 4:47.
The rabbit seems well. However, it is seized by paraplegia about
6 o'clock, still preserving its sensibility; still living at 7:30; found
dead the next day.
Experiment DLXIX. July 2. White cat placed beside the rabbit
of the preceding experiment.
Taken to 10 atmospheres, decompressed regularly in 20 minutes.
The white cat cries out, breathes with difficulty; at the end of
a few seconds, seems furious, bites itself, bites the gray cat of the fol-
lowing experiment, which is stretched out near it. Has convulsive
quiverings; its pupils are very much dilated. Dies in 5 minutes. With
the greatest precaution I draw gas from the right heart; the 23.8 cc.
of gas which I obtain thus contain 15.9% of CO,, the rest is nitrogen,
without a trace of oxygen.
Gas in all the circulatory system: veins, arteries, portal system,
inner vessels of the spinal cord. The latter is very hard and shows
no sign of tearing.
Experiment DLXX. July 2. Gray cat, placed beside the animals
of the two preceding experiments.
Is dying when taken out, and dies immediately afterwards.
876 Experiments
I draw from its right heart 33.1 cc. of gas, which contains 17%
of CO,.
Same results at autopsy as in the preceding experiment.
Experiment DLXXI. July 10. Dog of Experiment DXXIX.
From 2:40 to 3:40, taken to 10 atmospheres. As it approaches 10
atmospheres, has a sort of convulsion.
Under pressure for 30 minutes.
Decompressed from 10 to 6 atmospheres in 1 minute; then from
6 to 1 in 1 hour. Same convulsions during the decompression.
As it leaves the apparatus, it cannot stand-up on its hind legs;
howls and whimpers; lies down on its side; trembling and strong
extension of its front feet at every inspiration. Hind legs flexed,
motionless, but sensitive.
About 5:30 gets up, walks a little, slowly, then lies down again,
still weak in the hindquarters.
July 11. Well.
Experiment DLXXII. July 23. Dog of Experiment CLXXXII.
At 5:08, dog taken to 10 atmospheres; at 5:15, dropped in 2 min-
utes to 6 atmospheres; at 5:45, dropped in 2 minutes to 3 atmos-
pheres; at 6:33, decompressed in less than 30 minutes.
No immediate or delayed symptom.
Experiment DLXXIII. July 27. Dog of Experiment CLXXXIII.
Taken to 10 atmospheres, 143 cc. of blood drawn.
Decompressed at the rate of 1 atmosphere per 3 minutes, very
regularly.
The operation is over at 5:45.
Removed at 6 o'clock, is paraplegic: right leg almost insensible,
left one slightly sensitive, tail sensitive.
At 7 o'clock, difficult breathing. Ascending paralysis which has
invaded the whole body; the ribs no longer move; breathing purely
diaphragmatic.
Found dead the next day.
Experiment DLXXIV. August 7. Bitch taken to 10 atmospheres,
128 cc. of blood drawn. (See Exp. CLXXXV.)
I make the decompression by means of the graduated cock; in 20
minutes, the pressure drops 2Vz atmospheres; in the following 20 min-
utes, it drops 1V4 atmospheres, and 1% atmospheres in the following
16 minutes; it is then 4V2 atmospheres, and I open the large cock,
which restores normal pressure in 3 minutes.
It is all finished at 7:31.
Removed at 7:40, the animal is completely paralyzed; gurgling
heard in the heart: 80 extremely irregular heartbeats; 80 to 100
respirations, still operated somewhat by the ribs; no apparent un-
easiness; great quantity of froth in the mouth.
Dies at 8 o'clock.
Left heart: dark blood with a little gas. Right heart: dark blood
frothy with fine bubbles of gas.
Gas in all the veins and arteries, except the veins of the portal
system, while the mesenteric arteries are full of it.
Sudden Changes in Pressure 877
Abundant foam in the stomach and intestine, but not enormous
or dangerous from its volume. Foam in the bronchi: lungs healthy,
without congestions and effusions.
Experiment DLXXV. August 8. Dog taken to 10 atmospheres,
and bled of 133 cc. (See Exp. CLXXXVI.)
Decompressed in 50 minutes, very regularly, that is, about 5 min-
utes per atmosphere.
Normal pressure established at 7:30.
At 7:35, very loud gurgling heard in the heart. The animal,
when placed on the floor, is paralyzed in the hindquarters and the
ribs. Rectal temperature 39°.
8:30, very loud gurgling on the right, much less on the left;
progressive paralysis; the animal is conscious and raises its head
when called; rectal temperature 36°.
9:30, state still more serious; temperature 35°; the eyes are al-
most the only movable parts. Still loud gurgling on the right, less
on the left.
Found dead the next day.
Experiment DLXXVI. August 9. Dog.
Taken from 8 o'clock to 9:12 to 10 atmospheres; seems to undergo
a sort of convulsive struggling in the apparatus.
Decompressed very regularly in 1 hour and 30 minutes, that ::s,
10 minutes per atmosphere.
Taken out at 10:42, gay and well.
At 10:47, the left front leg stretches out, then is paralyzed in
movement but remains sensitive.
At 10:50, the animal falls, the right hind leg is stretched out,
paralyzed in movement.
10:55, this leg is better, but the left hind leg is .affected in its turn.
11 o'clock, the whole left side is paralyzed, but sensitive.
Experiment DLXXV II. October 25. Vigorous dog placed free in
the large apparatus.
From 2:30 to 4 o'clock, the pressure is taken to 10 atmospheres.
About 3:50 the dog, which has howled all the time it has been in
the apparatus, is seized by an attack of tonic and clonic convulsions
which lasts some 20 seconds.
After this, it remains weak and staggering for some minutes.
At 4:10, the animal seems well; decompression is made by pass-
ing abruptly from 10 atmospheres to 8, from 8 to 6, from 6 to 4, from
4 to 2, from 2 to 1. At each stage, a pause of 15 minutes is made.
The whole decompression lasts 1 hour and 10 minutes.
No symptom has appeared during the decompression. The
cylinder is opened, and the animal comes out freely. But after 2 or 3
minutes, it utters cries of pain.
At 5:45, it lies down; the hindquarters are stiff; when it is forced
to stand up, it lifts the left front foot, which seems to give it pain.
At 6: 15, is howling less, but is still in the same state.
Well the next day.
878 Experiments
Experiment DLXXVIII. October 28. Dog of the preceding ex-
periment, quite recovered.
Taken to 10 atmospheres; after 5 minutes, has an attack of con-
vulsions. At the end of 15 minutes, decompression is made at the
rate of 8 minutes per atmosphere, very regularly, the whole requir-
ing 1 hour 12 minutes.
Shows no symptom either immediate or delayed.
Experiment DLXXIX. November 14. Dog.
Taken to 9 atmospheres. Decompressed in about 1 hour.
When taken from the apparatus, its rectal temperature is 20°.
It has loud gurgles in the heart and soon dies.
Experiment DLXXX. June 27. Dog weighing 19.3 kilos.
From 1 o'clock to 2 o'clock is raised to IVz atmospheres, with
a current of air. A leak develops; at 3 o'clock, the pressure is 6
atmospheres; at 6:45 it is only AVz atmospheres, in spite of the con-
stant pumping.
Decompressed from 6:45 to 7:45.
When taken out, the big dog is very wet, cold, dying; it dies after
a few breaths. Pulmonary ecchymoses are found, and gas everywhere
in the blood.
Experiment DLXXXI. June 27. Two puppies, very young, weighing
about 1.5 kilos. n
Placed beside the animal of the preceding experiment.
The puppies are also very wet; but they show no symptom, either
immediate or delayed.
I summarize in Table XIX the data relating to the progressive
and slow decompression.
3. Summary and Conclusions from the Preceding Experiments.
Let us now consider these experimental results in their entirety.
The first striking fact when we examine Table XVIII is that sudden
decompression is much less dangerous to birds than to mammals.
A sparrow, in fact, (Exp. DX) survived the decompression from 10
atmospheres, another (Exp. DXIII) did not die for a long time
after a decompression from 14 atmospheres.
On the contrary, in mammals, symptoms began to appear at 6
atmospheres (Exp. DXXX) ; death struck almost all the animals
decompressed from 8 atmospheres, and all of those decompressed
from 9. Dogs and cats seemed even more susceptible than rabbits;
Experiments DXX and DXXVI made simultaneously on a cat
which died and a rabbit which survived, are characteristic, except
for individual differences.
In the same species, in fact, we notice differences which are
very important. In dogs, for example, we have always had severe
Sudden Changes in Pressure
Table XIX
879
Species
of
animal
Duration of
decompression
Condition of animal
DLXVII | Rabbit | 10
| Cat
(DLXVIIII Rabbit
DLXIX I Cat
I
DLXX
DLXV
Cat
Guinea 1
1 Pig
[ DLXVI | Cat
j DLXXXI
| DLXXX
Puppies
Adult
dog
DLXXIX | Dog
DLXXIII | id.
I
DLXXV I id.
DLXXVIII I id.
DLXXVI
DLXX
DLXXIV
DLXXVII
DLXXII
id.
id.
id.
id.
id.
10
5 hours of compression;
decompressed in 2 hrs.
2 m. per atm. 20 min.
2 m. per atm.; 20 min.
2 m. per atm. 20 min.
From 10 to 5 atm. in 1
min.; from 5 to 1 in 30
min.
1 hour from 7V2 to 6; I
3 h. 45 min. from 6 to
4V2; l h. from 4V2 to 1.
In about an hour
3 min. per atm. 27 min.
5 min. per atm. 50 min.
I
10
I
I I
8 min. per atm. 1 h. 12|
min.
10 min. per atm. 1 h.
30 m.
From 10 to 6 in 1 min.;|
from 6 to 1 in 1 hour.|
I
From 10 to 7V2, 8 m.
per atm.; from IVi to
6V4, 15 m. per atm.;
from 6y4 to 4%, 9 m.
per atm.; from 4 ¥2 to
1, 3 m. per atm. In all,
1 hour.
Abruptly from 10 to 8;
from 8 to 6; from 6 to
4; from 4 to 2; from 2
to 1. At each stage, 15
min. pause. In all, 1
hour, 10 min.
From 10 to 6 in 2 min.;!
left 30 min. at 6. From
6 to 3 in 2 min.; left
45 min. at 3. From 3
to 1, about 15 min. In
all about 1 hour, 30
min.
No symptoms.
No symptoms.
Paralyzed after 1 hour,
lived more than 3 hrs.
Dies in 5 min. 23 cc.
of gas in heart (CO,
17, N. 84.1).
Taken out dying. 33 cc.
of gas in heart (CO,
17, N. 83).
Dies in 15 min.; gas in
venous system only.
No symptom.
No symptom.
Withdrawn dying. Gas
everywhere.
Dies quickly.
Paraplegia. Died dur-
ing night.
Gurgling; progressive
paralysis. Dies during
night.
No symptom.
Slight symptoms; sur-
vives.
Slight locomotor dis-
turbances; recovers.
Animal of Exp.
DXXIX.
Completely paralyzed;
gurgling; dies in 20
min. Gas in all the
blood.
Comes out of the ap-
paratus without help:
soon howls.
Locomotor disturb-
ances.
Recovers and survives.
No symptom.
380 Experiments
symptoms, often death, at 7 atmospheres, except the animals of
Experiments DXLIX and DLII which resisted the decompression
of 7V2 atmospheres, and that of DLV which survived even SV2.
This last animal, from this point of view, is particularly interest-
ing. In a series of sudden decompressions, beginning with IV2 at-
mospheres (Exp. DLII and DLIII) , then with 8 atmospheres (Exp.
DLIV and DLVI), and even 8V2 atmospheres (Exp. DLV), it
showed no sign of sickness. Then four months later, decompressed
from 8 atmospheres, it died in less than a half -hour (Exp. DLX) .
During the first series of experiments, it was thin and in very bad
shape; at the time of the last, on the contrary, good care had made
it fat and healthy.
Must we attribute the difference in results to this difference in
condition? The cause, purely physico-chemical, which we shall be
compelled to attribute to the symptoms of decompression, does not
lend itself to this interpretation. Furthermore, Experiment DLVII
shows us a dog in just as bad a condition, at least, which at the first
trial, died from a decompression beginning with 8 atmospheres.
No less inexplicable is the resistance of the puppies of Experi-
ment DLXXXI when the adult dog placed beside them during more
than 5 hours (Exp. DLXXX) died immediately after a slow decom-
pression, beginning with IV2 atmospheres.
But setting aside these irregularities which may suggest im-
portant considerations in practice, let us now examine the symp-
toms in themselves.
In sudden decompression beginning with 8 atmospheres and
above, we have seen almost always a practically instantaneous
death. It appeared also, but more rarely, in decompressions begin-
ning with 7 to 8 atmospheres. Generally then the symptoms con-
sisted of a paralysis of the hind legs, a paralysis sometimes slight
and transitory, sometimes persisting for several days, sometimes,
finally, rapidly ascending and involving death by asphyxia after
several hours.
The cases in which the paralysis receded were, as one might
expect, the limited cases (Exp. DXXX, DLXXI, DLXXVI) ; the
limbs alone had been affected; voluntary movement alone had been
lessened. These symptoms disappeared of themselves in less than
an hour; all that I saw last longer continued till death.
When death occurred, we usually found to explain it and to
explain the more or less complex phenomena which had preceded
it, a more or less extensive softening of the spinal cord, much ad-
vanced in the lumbar regions, and making progress in the rest of
Sudden Changes in Pressure 881
the organs, in which inflammatory lesions like those described in
Experiments DXXVI and DXXXIV preceded it.
There now remain to be explained at the same time the initial
cause of these cases of paralysis of greater or less length, and the
reason for the almost immediate death which so often occurred.
Let us say next that the hypothesis of M. Bouchard is not at all
verified. We have indeed sometimes found the stomach and intes-
tines slightly distended by gases; but, besides the fact that this
distention has never been very great, we have never seen in the
lungs or nervous centers the congestions and hemorrhages to which
sudden death is due, according to this author. Furthermore, in all
cases, we have noted the persistence of the heart beats, and there-
fore we must set aside also the idea of syncope.
We can go still further. The evident proof that the symptoms
which attack decompressed animals are not due to abrupt oscilla-
tions of the blood which has been driven back by sudden expansion
of the intestinal gases is easily drawn from the experiments re-
ported in Chapter IV. We see indeed that dogs could be brought
in a few minutes from 7 or 8 atmospheres to normal pressure with-
out showing symptoms similar to those which have just been de-
scribed, with which it is impossible to confuse the phenomenon of
oxygen poisoning, of which they presented the strange and terrible
picture.
But the true cause of all these symptoms was shown very clearly,
and the hypothesis of MM. Rameau and Bucquoy (see page 501)
received the strongest confirmation from our experiments. The
gases of the blood, as the professor of Strasburg had foreseen, are
liberated under the influence of sudden decompression, and then
cause symptoms comparable to those of an injection of air into the
veins. But the phenomenon is more varied and complex than the
learned physicist could have thought it.
In the first place, it is not the three gases of the blood, as he
thought, that thus regain their gaseous form. We might have
foreseen this result, because our previous researches (Chapter II,
Subchapter III) had showed us that the proportion of the oxygen
is hardly increased by pressure, and that of the carbonic acid is not
increased at all. We were therefore in a position to state, and
we might have thought that we had the right to do so, that the
gas which would threaten life on being liberated would be ex-
clusively the one the proportion of which was considerably in-
creased in the blood, that is, nitrogen.
This conclusion could also be drawn from the experiments of
882 Experiments
Chapter IV to which I alluded a moment ago; here no symptom
appeared, no gas bubble was freed in the vessels, because the air
which the animals were breathing had a very low nitrogen content.
But there is better proof; I could, as Experiments DXXVIII,
DLVIII, DLXIX, and DLXX show, extract the gases collected in
quantity in the heart and analyze them. I did indeed find them
composed chiefly of nitrogen; but I must confess that I was much
surprised to find, besides the nitrogen, a quantity of carbonic acid
which varied from 15% to 20% and even, in one case (Exp. DLVIII) ,
a little oxygen.
The explanation of these facts should probably be drawn from
the circumstances that the liberation of the nitrogen takes place in
little bubbles, which the circulatory movements stir up before they
can collect in the heart in vast collections of gas, so that the blood
is, as it were, traversed by a current of nitrogen. Now we have
known for a long time that such a current carries with it much
carbonic acid.
As for Experiment DLVIII in which I found 2% of oxygen, that
is the one in which the apparatus exploded, and in which the ani-
mal, which was killed instantly, had not consumed the slight excess
of oxygen which had been liberated in its blood.
At any rate, most of the free gas is made up of nitrogen, and
from this fact a very serious danger results; for carbonic acid and
even oxygen might be redissolved rapidly, and Nysten - long ago
demonstrated that their presence in the venous system is not dan-
gerous, unless enormous quantities, especially of carbonic acid, are
introduced. It is true that in our experiments there is gas in the
arterial system itself.
It is probable that all the excess nitrogen thus passes to the
gaseous state. Now we have seen that at 10 atmospheres there are
about 8 cubic centimeters of nitrogen in excess in 100 cubic centi-
meters of blood. Supposing that a dog weighing 14 kilograms con-
tains 1 kilogram of blood, we find that there may be liberated in
the arterial and venous vessels 80 cubic centimeters of nitrogen,
bringing with them about 20 cubic centimeters of carbonic acid;
that is sufficient to bring on symptoms that are immediately fatal.
Now we can picture the effects of sudden decompression. Let
us first represent things as bad as possible; let us suppose an animal
brought in 2 or 3 minutes from 10 atmospheres to normal pressure.
Immediately, in the whole vascular system, gases escape in abun-
dance; there is frothy blood in the veins, in the arteries, in the
portal system, even in the vessels of the placenta and the foetuses,
Sudden Changes in Pressure 883
when the animal was pregnant (Exp. DXXXVI) . The heart, which
continues to beat for a few minutes more, pumps into the arteries
the gases which its left cavities contained, although they are rarely
found there; the course of the venous blood, which continues a
little while, brings to the right cavities tiny bubbles of gas which
collect there in such quantity that a cat (Exp. DLXX) furnished
me with 33 cubic centimeters of it, and a little blood freed of
gaseous bubbles proceeds to the left heart by some of the pul-
monary arteries. The others are obstructed by the foam sent out
by the right heart. We find here the effects of this difficulty which
gases have in passing through the capillaries, difficulties which so
often cause the injections of anatomists to fail: we see bubbles of
gas refusing to pass through the lungs, and in certain experiments
we have seen the mesenteric arteries full of bubbles of gas without
the blood of the portal vein containing any.
Let us suppose now the lightest case, either of an animal decom-
pressed from only 6 atmospheres (Exp. DXXX) , or, beginning with
10 atmospheres, of one decompressed very slowly (Exp. DLXXI,
DLXXVI, and DLXXVII) . In these cases, bubbles of gas will be
liberated, though smaller and much less numerous; those of the
venous system will stop in the lungs, and will cause some respira-
tory difficulties; then when they have been agitated and made ex-
tremely small (one sometimes needs the microscope to see them) ,
they will reach the left heart and thence be pumped into the
arteries, where they will join those which spontaneously developed
there and which the circulation has not yet driven into the veins.
It may be that they will finally be redissolved without causing
any very definite symptoms; but if, unfortunately, some of them,
drawn by the circulation into the capillaries of the nervous sys-
tem, check locally the course of the blood there, immediately, in-
stantaneously, as in the experiment of Stenon, a paralysis or a
local excitation is the result; only in the case in point, the bubble
is so small that it soon disappears and everything returns to the
normal state.
We understand that between these two extremes there must lie
many intermediary cases, and the experiments reported above pre-
sent plenty of examples. Nothing is more startling than to see
animals decompressed from 6 to 8 atmospheres leaping out of the
apparatus, as if delighted with their liberty, then seized after a few
minutes by a paralysis which always begins in the lower limbs,
but which often invades next all the rest of the body.
Another surprising thing is this interval of 5 to 10 and even 15
884 Experiments
minutes which almost always elapses between the moment of de-
compression and that of paralysis, either because the gas does not
escape immediately in the whole body, or because a certain time
is needed for the bubbles of air to cut off the medullary circulation.
It is no less strange to see, in certain experiments, for instance
DLXXV, life persisting for hours when the almost general paraly-
sis of the animal left free only the movements of the diaphragm,
and gurgling could be heard in the heart, revealing at the begin-
ning the presence of a great quantity of gas in the right heart and
the lungs.
In this case, the animal is slowly asphyxiated, as is proved by
the increasing darkness of the blood flowing in its arteries. It is
evident that the pulmonary output is insufficient to provide an
adequate quantity of oxygenated blood in the arteries.
If now we ask why the nitrogen thus liberated is not finally
redissolved in the blood, or why it does not escape through the
lungs, the reply is easy.
As a matter of fact, the blood circulating through the vessels
under normal conditions is almost saturated with nitrogen through
the respiration of air; when arterial blood is shaken with air, it can
be made to absorb only some tenths of a cubic centimeter of nitro-
gen more than it already contained. There is no reason then why
the excess which has been liberated should be redissolved. Now
the free nitrogen does not escape through the lungs because it is
in an atmosphere which is four-fifths nitrogen, and nothing urges
it out.
Continuing this reasoning, we begin to think that there might
be an advantage in causing the animal to inhale pure oxygen or a
mixture of oxygen and hydrogen, to stimulate at the same time
the dissolving of the nitrogen in the blood and its diffusion through
the pulmonary membranes. And this I did with some success in
the experiments which I shall report later.
Finally, a third strange fact, the paralysis always began in the
hindquarters (except in Experiment DLXII) . Why is this place
selected? Is it a sufficient explanation to say: the lumbar region
of the spinal cord is the part which works hardest when the ani-
mal jumps and runs? I merely remind the reader that paraplegia
is also the most frequent symptom in divers and workmen in
caissons.
When death occurs shortly after the beginning of the paralysis,
it is evidently under the influence of the same cause as the paralysis;
the bubbles of gas, after cutting off the circulation in the lumbar
Sudden Changes in Pressure 885
enlargement, check it in higher points (where autopsy finds them)
until finally respiration ceases; during this time, besides, the pul-
monary arteries are filled with free gases; asphyxia comes every-
where at the same time.
But it has happened sometimes that the paralysis was localized
in the lower limbs, or at least has made only rather slow ascending
progress; so that death occurred only after several days (Exp.
DXXIV, DXXVI, DXXXIV) . If we consider the lack of care for
the animals, we may think that some might survive, though para-
lyzed, as happens to some divers.
At death, there was found, as we have already noted, a more
or less extensive softening, in the midst of which bubbles of gas
(Exp. DXXVI) were sometimes seen even after 4 days, and which
were surrounded by the inflammatory processes which had caused
death. I call attention to the rapidity with which a softening oc-
curred so great that the spinal marrow was liquid like cream; in
Experiment DXXIV, it was less than 24 hours.
I shall only mention to the reader the remarkable physiological
symptoms which accompany these interruptions of the medullary
circulation and the following changes in metabolism. Those who
have had the patience to read the preceding experiments must have
noted the strange occurrences of an emission of bloody urine and
sperm, of contraction of the limbs, of constriction with exagger-
ated reflex movements of the anal and bladder sphincters, of sensi-
tivity retained after the loss of motility, etc. I shall only recall
here the curious point of the afferent and efferent conductivity of
the sciatic nerve, so much affected by the change in the corre-
sponding region of the spinal cord (Exp. DXXXIV) . I consider
that these softenings produced experimentally might contribute
greatly to the progress of the physiology of the spinal cord, and
render useful services to the medical diagnostician: it is a mine to
be worked which would be as prolific as the one which gave so
many useful results in the skillful hands of Professor Charcot.
Some of the experiments reported above show that the presence
of bubbles of gas in the blood is not a necessary cause of death or
even of symptoms manifest to the eyes of the observer. Thus in
Experiment DXXXIX, in which the pressure was 3V2 atmospheres,
from the blood received under mercury in a test tube very small
bubbles of gas escaped, and yet the animal, decompressed in 1
minute, did not seem at all affected. Looking very closely and
using a magnifying glass, I even saw in one case (Exp. CLXXXIV)
886 Experiments
the bubbles of free gases escaping under mercury from the blood
of a dog placed at 3 atmospheres.
It is evident that in the dog of Experiment DXXXIX, which
was some days afterwards decompressed from 5 atmospheres with-
out symptoms, the blood in circulation contained fine bubbles. But
they could pass through the capillaries without obstructing the cir-
culation, and probably were dissolved more or less rapidly.
The presence of such bubbles would be enough, I think, even
if there were no stoppage of the circulation, to explain, on the
basis of irritation of the tissues, the slight symptoms of workmen
in caissons, the "puces" (fleas) and the "moutons" (sheep), dis-
cussed in the historical part. We therefore understand the risks
run by these workmen, whose paralysis or death at these limits
depends upon the size of a bubble of gas. It is not surprising then
that symptoms, slight in some and fatal in others, appeared after
too sudden decompression from about 4 atmospheres.
But the presence of bubbles of nitrogen in the blood, irritating
the tissues in contact with them, when they are small enough to
traverse the capillaries, or causing more serious and more lasting
symptoms, when they interrupt the circulation, does not constitute
the only danger to which animals rapidly decompressed are ex-
posed, nor is it perhaps the most dangerous.
Indeed, the very tissues of the organism, which are impregnated
with liquid, and the liquids other than the blood are laden with a
growing proportion of nitrogen, from contact with the blood which
is supersaturated with it. And when the decompression occcurs,
these gases must necessarily return to a free state, distending and
even lacerating the tissues from which they escape. Experiments
DXXXVI, DLVIII, DLIX, DLX, and DLXIII have shown us gases
in the subcutaneous or intermuscular tissue, in the liquids of the
eye, in the cerebro-spinal liquid, in the spinal cord, etc. Experi-
ment DLVIII, in which the explosion took place, is quite remark-
able in this reference; the subcutaneous emphysema was such that
the dog had become absolutely cylindrical. Let us mention par-
ticularly also Experiment DXXXVI, in which in a pregnant bitch
we found gas not only in the blood vessels and tissues of the ani-
mal, but also in those of the foetuses, and even in the allantoid
liquid; the amnion, which is much less vascular, contained none.
These gases, imprisoned in the meshes of the tissues, must, when
they do not cause death, be the cause of pains and local swellings,
and it is evidently to them that we must ascribe the muscular
Sudden Changes in Pressure 887
swellings, the swelling of the breasts, etc., of which we have given
several examples in the chapter devoted to history.
In summary, sudden decompression causes many more or less
severe symptoms, all of which are easily explained by the libera-
tion in the blood plasma as well as in the interior of the tissues,
of the nitrogen which was dissolved in excess under the influence
of the pressure.
I admit that, in this collection of data which, although infinite
in variety, still has a single simple cause, one point still surprises
me. I cannot understand why, m certain dogs subjected to high
pressure, the blood extracted from the vessels did not contain free
gases: for instance, in Experiments DXLVI and DLVI, in which
the pressure was 6V2 and 8 atmospheres. Experiment DLXIII is
particularly interesting in this connection: the dog, decompressed
after a long stay at 6 atmospheres, was paralyzed, and yet no free
gas appeared in its blood; but the symptoms having grown more
serious, gas was found after death not only in the blood but also
in various organs, and particularly in the spinal cord: this was
probably the cause of the immediate paralysis.
It was also somewhat difficult at first to understand why dogs
suddenly decompressed from 5 or 6 atmospheres, rabbits from 6,
7, 8, and sparrows from 8, 9, 10, did not die, and did not even show
any symptoms, though they certainly had free gases in the blood,
since I sometimes observed the presence of gas in an experimental
animal, as in Experiments DXXXIX and DLXIV. I think that this
apparent anomaly should be explained by the fact that the escape
of bubbles which were very small at the time permitted them to
pass without hindrance through the system of capillaries and to
gather in the venous system. Now if all the gas thus set free is
collected in the veins, it cannot constitute a serious danger for the
animal.
Let us consider again a calculation which we have already made.
At 5 atmospheres, for example. Table XII shows that a dog has an
average of 6 volumes of nitrogen per 100 volumes of blood, that is,
about 4 volumes more than the blood can dissolve at normal pres-
sure. Let us take a dog weighing 10 kilos, and let us suppose that
it has in its blood and lymph vessels 1 liter of liquid; there will
be 40 cc. of nitrogen, with about 10 cc. of C02 which, as a maximum,
will collect in the hollows of the right heart. This collection will be
made progressively, for it is well known that in a liquid super-
saturated with gases by pressure, the gases will not escape instan-
taneously at the time of the decompression.
888 . Experiments
Now the 10 cc. of carbonic acid will be dissolved again or will
be given off at once by the lungs; as for the 40 cc. of nitrogen,
which corresponds to what would be present in 50 cc. of air, we
know that although such a volume of air, injected suddenly into
a vein of the heart, can check the contractions of this organ, espe-
cially when this air is cold, one can, on the contrary, introduce
without harm into the circulatory channels much larger quantities
of air, if moderate and successive injections are made.
Nysten" long ago demonstrated this fact; but since misapprehen-
sions on this point are still common, I think I should report a few
very convincing experiments in this connection:
Experiment DLXXXII. February 24. Little dog, weighing 4 kilos,
sick. Injected into the jugular vein in 4 minutes 14 cc. of air. The
animal dies in 10 minutes.
Bloody foam in the right heart and the pulmonary artery; no gas
in the left heart.
Experiment DLXXX1II. July 25. Dog weighing 5 kilos. Outer
temperature 21°.
At 3 o'clock, single injection -in the left femoral vein of 20 cc.
of air.
Immediately the heart is heard to beat with the noise of a dry
sponge being squeezed under water. The animal ceases to breathe;
the heart seems to stop; the conjunctiva, but not the cornea, becomes
insensible.
Then the respirations begin again, at first very rare and very
deep, then hasty. The heart sounds reappear, normal.
3:15; new injection of 20 cc. Same phenomena, although less
pronounced: sensitivity, respiration, heart beats do not completely
disappear; stiff enings of the front legs; little cries.
3:25; the animal seems quite recovered. Injection at one time of
40 cc. of air. Immediately stiffenings of the legs, heart sounds, respir-
atory difficulties; the whole condition becomes worse, and at 3:35
the heart can no longer be heard.
Autopsy at 3:50. Right auricle and ventricle full of blood frothed
with air, with clots full of air; a little gas in the vena cava. No air
in the pulmonary arteries or the left heart.
Experiment DLXXXIV. February 14. Bulldog weighing 12 kilos.
Progressive injection in 9 minutes of 130 cc. of air, into the left
jugular vein.
Seems rather uneasy during the injection, but released imme-
diately after, is in good condition.
Experiment DLXXXV. February 24. Vigorous hunting dog, weigh-
ing 15.5 kilos. Outside temperature 14°.
3:15. Every two minutes, an injection of 65 cc. of air in 30 seconds
into the right jugular vein, with an excellent glass syringe.
At each injection the animal moans, and immediately, even at a
distance, the sounds of heart gurgles are heard.
Sudden Changes in Pressure 889
After the 10th injection (650 cc), the animal does not seem to be
in danger. At the 24th minute, injections are resumed, but this time
every minute.
After the 17th injection (1100 cc), the animal groans, urinates,
stretches out its legs with force. The heart beats grow slow, the
respirations are very rare, and the animal dies at 3:55. Its temper-
ature dropped 1°.
1 found the right heart full of foam, blood frothed with air, with
a large quantity of free air; it was present also in the venae cavae
and the pulmonary arteries.
Numerous bubbles of air in the left heart and the cardiac arteries
and veins; there was none in the arteries of the limbs and the portal
•vein.
In Experiment DLXXXII, a dog, which was small, it is true, and
sick, was killed by an injection of 14 cc. of air, while in Experi-
ment DLXXXV, it was necessary to go as high as 1100 cc. to kill
a large dog. These experiments, in short, show us as many differ-
ences for artificial injections of air into the veins as for the sort of
physiological injection which takes place during sudden decom-
pression.
One of the most important elements to be considered in regard
to the appearance of morbid symptoms following decompression is
the length of the stay in the compressed air. This plays the prin-
cipal part, after the degree of compression and the speed of the
decompression. So, whereas for dogs decompressed immediately
after the desired degree had been reached there are no serious symp-
toms, as Table XVIII shows, before reaching 7 atmospheres, in Ex-
periment DLXIII, we see a dog dying quite rapidly after leaving
the apparatus in which the pressure of 6 atmospheres had been
maintained for 3V2 hours. Experiment DXV made on a sparrow is
still more remarkable. However, Experiment DLXIV shows us a
dog which had no symptoms after a stay of 4 hours under 5V2 at-
mospheres; but he had in his blood abundant bubbles of gas, and
was consequently under the threat of an imminent morbid attack.
In conclusion, it is possibly interesting to note that aquatic ani-
mals are killed by sudden decompression for the same cause as
terrestrial animals and by the same mechanism. But it will no
doubt seem enough to report one experiment to support this state^
ment which presents true interest in regard to the conditions of life
of these creatures:
Experiment DLXXXVI. April 6. Eels "de la montee" (young),
transparent, subjected for two days to a pressure of 10 atmospheres
of air.
2 o'clock, decompressed suddenly; emit from their mouths bubbles
of gas.
90 Experiments
6 o'clock, all dead; the hearts, which are full of air, can be seen
beating; because of the transparency, bubbles of gas can be seen in
all the vessels.
Subchapter IV
PROPHYLAXIS AND TREATMENT OF SYMPTOMS
OF SUDDEN DECOMPRESSION
Considering these dangerous symptoms, a double question is
naturally suggested: how to prevent them, and how to cure them.
They will be prevented, as common sense suggests and ex-
perience proves, by making the decompression slow enough. On
this point the experiments summarized in Table XIX give very
clear indications. We see, for example, that from 10 atmospheres
on, we avoided serious symptoms by giving more than 1 hour and
10 minutes to the decompression (Experiments DLXXI, DLXXII,
DLXXVII, DLXXVIII). But this is the minimum time, since an
hour, in Experiment DLXXIV, did not prevent death. I set aside
Experiments DLXXX and DLXXXI, which show a peculiarity that
I still cannot explain.
I did not perceive great differences between the cases in which
the decompression was made continuously at the rate of 8 minutes
per atmosphere (Exp. DLXXVIII), or 10 minutes (Exp. DLXXVI),
and those in which it was made by sudden drops with intervals of
rest (Exp. DLXXII, DLXXVII) . Besides, the data are not numer-
ous enough to permit conclusions in favor of either of these
methods.
But it is certain that beginning with 10 atmospheres one cannot
be sure that a dog will be out of danger unless the decompression
is given a duration of at least 12 minutes per atmosphere. We
shall return to these data in the third part of this work.
And now for the second question. The decompression was made
too quickly. Gases escape into the blood, which obstruct certain
vessels and threaten the experimental animal with death. Evi-
dently I should have thought of causing them to be redissolved by
subjecting the animal to a new compression with the purpose of
decompressing him with controlled slowness. And that is what I
did in the two following cases:
Experiment DLXXXVII. October 18. Dog of Experiment DXXXVIII.
It is paraplegic as a consequence of a sudden decompression from
7 atmospheres; the paraplegia began at 3:21.
Prophylaxis of Sudden Decompression 891
From 3:25 to 4:05 was taken again to 7 atmospheres, and kept
there until 4: 12. Then decompressed slowly; normal pressure was
reestablished at 6 o'clock.
On leaving the apparatus, the animal is still paralyzed in the
hindquarters, or rather, its hind legs, stiff and contracted, no longer
are controlled by the will; sensitivity remains, and we obtain reflex
movements by pinching, but very slowly.
Dies during the night.
Experiment DLXXXVIII. October 16. Dog of Experiment DXXXVII.
Paraplegic and stiff since 2 o'clock, as a consequence of a decom-
pression from 7 atmospheres. Recompressed to 7 atmospheres from
2: 15 to 3:02, then decompressed in an hour.
The animal seems better and calmer; but it is still paraplegic
though not stiff; the temperature of the hind legs has risen.
Dies the next day.
No gas is found in the vessels; but the spinal cord presents, from
the lumbar enlargement to the middle of the dorsal region, little
bloody spots scattered in the antero-lateral fasciculi. There is no
softening.
I did not multiply these experiments; it is evident that the
recompression was managed here too slowly for it to be possible
to draw any conclusion from these results. However, I do not
doubt the effectiveness of this method, on condition that one could
obtain a very rapid recompression. We saw in the historical part
that it was already used by workmen and recommended by the
physicians who had attended them.
The considerations already presented (Page 884) had put me on
the track of a quite different method, which aimed not at redissolv-
ing the bubbles of free gases in the blood, but at forcing them to
escape through the respiration.
These bubbles are composed, I have said, of nitrogen; when
they reached the pulmonary capillaries, there is not much likeli-
hood that they will be diffused and mingle with the air of the
lungs, because that air also is four-fifths composed of nitrogen.
Considering this, I thought that if the animal were caused to
breathe a gas containing no nitrogen, pure oxygen, for example,
the diffusion would take place much more rapidly, and perhaps
would even be rapid enough to cause all the gas to disappear from
the blood, and thus save the animal. I' give here the results of some
experiments performed in this way:
Experiment DLXXXIX. October 31. Dog of Experiment DXLIII.
Decompressed from 7 V4 atmospheres, lying down, very sick since
2: 15, with gurgling in the heart.
At 2:20, pure oxygen administered to him continuously.
At 2:30, the sound of gurgling has ceased, respiration is freer,
892 Experiments
the animal tries to rise using its front feet; its eyes are no longer wild.
At 4:30, use of oxygen discontinued. The animal is quite recov-
ered in regard to respiration and heart.
But it is still paralyzed, or at least cannot stand up on its feet,
although it moves its limbs and head spontaneously.
Found dead the next day. No gas in the heart or the vessels.
Experiment DXC. November 12. Dog of Experiment DXLV.
3:12. Decompressed from IV4 atmospheres, paralyzed, with loud
gurgles in the heart, and great respiratory difficulties.
3:20. We begin administering pure oxygen.
3:35. The respirations are very deep and frequent; there are no
sounds of heart gurgles. The animal makes general movements, and
tries to take off the muzzle with its paws.
The respirations become regular for a certain time, then they
decrease in intensity, and about 4:30, it is clear that the animal is
becoming exhausted and is going to die.
It is opened at 4:45, when about dead. No gas in the veins or
heart.
Experiment DXCI. November 25. Bitch of Experiment DXLVII.
Decompressed from 7% atmospheres, paralyzed at 3:23, gurgles,
lack of sensitivity, etc.
3:28. Since the respiration has stopped, we are obliged to give
artificial respiration with oxygen. After 6 to 7 artificial respirations,
spontaneous movements return, the heart begins to beat distinctly,
the gurgles diminish, insensibility disappears.
But at this moment the supply of oxygen fails and we cannot
continue the experiment; the animal dies almost immediately after-
wards.
We find the right heart much distended with blood, with only a
little foam.
Experiment DXCII. November 27. Dog of Experiment DXLVIII.
Paralyzed, very loud gurgles, decompressed from 7 atmospheres.
At the moment when oxygen inhalation has begun, the heart gurgles
seem to increase a little, then the heart almost completely ceases to
beat; gradually it becomes quite strong and frequent. But gas does
not cease escaping from the upper end of the jugular vein, which
has been exposed, and the animal dies after a half-hour.
Blood very red, and without gas in the left heart; blood fairly
red with tiny bubbles in the right heart.
Experiment DXCIII. December 6. Dog of Experiment DL.
Decompressed from IV2 atmospheres at 3:22. Immediately para-
plegic, front legs a little stiffened, but pulling back when pinched;
hind legs stiff and insensible; very loud gurgles.
I give oxygen inhalations and expose its jugular vein, which is
full of gas.
Immediately the respirations grow regular; little by little the gas
bubbles become smaller in the jugular, sensitivity returns a little to
the hind legs; the animal is evidently better.
Prophylaxis of Sudden Decompression 893
About 5 o'clock, the gases have completely disappeared from the
jugular, the animal raises its head when called by a whistle. The
oxygen inhalations are continued until 9 o'clock in the evening.
December 10. Is no longer completely paralyzed in the hind-
quarters; can stand up and drags its feet on the back of its toes when
walking. Exaggerated sensitivity in the hind legs. Disposition be-
comes bad.
December 11. Lying down, paralyzed; slight reflex movements of
the hindquarters. Very much exaggerated sensitivity in the front
legs. Rectal temperature 37.9°.
December 12. Dies.
Nothing noteworthy in the thoracic and abdominal viscera.
No medullary softening. Cross sections of the spinal cord show in
the white and the gray substances red dots which diminish progres-
sively from the lumbar region to the cervical region.
Experiment DXCIV. December 11. Dog.
Compressed to 8 atmospheres. Decompressed very slowly to 7%.
Then in 3 minutes to normal pressure; 5:15.
The animal is withdrawn immediately and given oxygen inhala-
tions.
5:25. Pulse 120; the rectal temperature, which before the experi-
ment was 38.5°, is 37.5°. Respiration regular; bubbles of gas are
visible in the jugular, which has been exposed.
5:30. Placed on the floor a moment; is paraplegic.
5:50. Pulse 90; there have been no gurgles in the heart; no more
gas is seen in the jugular; temperature 37.2°.
6:15. Use of oxygen discontinued; placed on the floor; is no longer
paralyzed, and drags the left hind foot on the toes only a little; the
hind legs seem insensible.
It is affected by a peculiarity of movement which makes it turn
to the right; its head is bent strongly towards the right, its eyes turn
in the same way. It has strong nystagmus and quiverings of the neck
muscles. When it wants to walk, it takes many precautions, then at
the least obstacle it falls, turning on its right side.
6:30. Manifest improvement; the hind legs and the tail are sensi-
tive; the animal walks much better and appears intelligent.
6:45. The improvement does not continue; the animal again drags
its left foot.
December 12. More paralyzed than the day before, can hardly
walk, and still turns towards the right.
Stimulus of the hind legs causes energetic reflex movements; but
the dog does not seem to notice it. The hind legs, especially the left,
are warmer than the others.
December 14. Still paraplegic, cannot stand up even an instant.
December 18. Same condition; urinates easily; energetic reflex
movements.
Experiment DXCV. December 13. Dog.
Taken to 8V4 atmospheres: decompressed in 3 minutes. Imme-
diately, at 3 o'clock, oxygen administered.
894 Experiments
It is not paralyzed; but after some minutes, paraplegia begins
and becomes complete, with reflex movements persisting.
No gurgles in the heart heard at all, and respiration goes on fairly
well.
4:50. Oxygen discontinued. The animal cannot stand on its hind
legs.
Respiration maintained well, heart beats are unaltered.
6:30. Same condition; sensitivity in the hind legs dulled.
December 14. Lying down, cannot stand on its hind legs, although
it can move them spontaneously, and perceives pricks in them. Dies
during the night of December 14-15.
The data which have just been reported, and the results of
which had already been listed in Table XVIII, show that one of
our anticipations was completely realized. Under the effect of
inhalation of pure oxygen, the gases contained in the veins and
the right heart diminished, then disappeared; the heart gurgles
either did not appear or stopped when the respiration of oxygen
began early. The danger of an immediate death, through stoppage
of the pulmonary circulation, was therefore averted.4
But yet we could not save our animals; the paralysis persisted,
and in spite of a real immediate improvement, ended in carrying
off our experimental subjects.
That is because the inhalation of oxygen could not bring back
into the blood stream and dispose of the bubbles of gas which
had stopped here and there in the capillaries of the central nervous
system. And it could not, for an even better reason, cause the
absorption of the bubbles which, as we have seen, escape into the
interior of the tissues.
Upon them, only recompression can have a beneficial effect.
But, on the other hand, recompression cannot cause a considerable
collection of gases in the right heart to be redissolved.
We are, therefore, led to recommend the successive use of the
respiration of oxygen, to eliminate the nitrogen stored up in the
right heart, and recompression to dissolve the bubbles which have
stopped in the capillaries or are scattered through the tissues.
Even so, we cannot be sure of a cure, because the bubbles of gas,
when they pass to a free state in the interior of delicate tissues, like
those of the spinal cord, may have caused disturbances or lacera-
tions there, the fatal effects of which cannot be averted by the dis-
appearance of the bubbles.
It is, then, upon preventive measures, that is, slow decompres-
sion, that industry must depend, and that is a point to which we
shall return in our third part.
Prophylaxis of Sudden Decompression 895
Subchapter V
SUMMARY
In summary, sudden decompression, beginning with several
atmospheres, brings on symptoms of varying severity depending
upon the degree of compression, the speed of the decompression,
the animal species, the individuals, and the state of the experi-
mental animal at the time.
These symptoms must be attributed to the escape of nitrogen
which had been stored up in excess in the organism, following
Dalton's law.
This gas changes to a free state in the blood vessels, the different
organic liquids, and even the interior of the tissues; it may there-
fore/ according to circumstances, check the pulmonary circulation,
soften and cause anemia in certain regions of the nervous centers
and especially the lumbar enlargement of the spinal cord, lacerate
the tissues, and produce swellings or a more or less extensive
emphysema. The severity of the symptoms depends upon both the
seat and the extent of these multiple disorders.
A controlled decompression of 12 minutes per atmosphere is
necessary to prevent these symptoms in dogs, when the compres-
sion has risen to about 10 atmospheres.
A recompression, either immediate or following the inhalation
of oxygen in case heart gurgles are observed, is the only means
of combatting successfully the symptoms of decompression.
1 At 3 atmospheres, gas escapes in the syringe from the blood drawn. ,
2 Recherches de physiologie et de chimie physiologique. Paris ,1811, p. 55 and 81.
3 hoc. cit., p. 15 et seq.
4 Consequently the inhalation of oxygen would be an effective means of checking the effects
of the introduction of air into the veins. With this in view, I have made a number of experi-
ments quite encouraging for surgeons.
Chapter VIII
VARIOUS QUESTIONS
In this chapter I deal with a number of questions which have
only a somewhat indirect connection with the subject of my re-
searches, but which are not, however, foreign to it. Such are the
questions of asphyxia and the toxic action of carbonic acid, which
has been so often mentioned, especially in the first chapter of
this work.
Subchapter I
ACTION OF CARBONIC ACID UPON LIVING BEINGS
The experiments reported in Chapter I, subchapter II, have
shown me that the death of animals confined in closed vessels, in
air compressed to several atmospheres, occurs when the tension
of the carbonic acid which they have formed by respiration rises
to a certain constant value.
This first observation attracted my attention particularly to the
study of the effects of carbonic acid upon living beings, so that
this study is connected indirectly to my project. It is the results
of these researches that I shall report here.
1. The Lethal Tension of Carbonic Acid in the Ambient Air.
I first remind the reader that the tension of a gas T is the
product of the two factors, the percentage C and the barometric
pressure P.
In sparrows, as we have seen, death occurs when the carbonic
acid tension rises to a value of 24 to 28, when, in other words, one
has the equation
C x P = 24 to 28.
896
Action of Carbonic Acid 897
And so, the higher the pressure, the lower may be the per-
centage necessary to cause death, and vice versa. Likewise, at
normal pressure and pressures below normal, to produce death, the
animals must have been confined in superoxygenated air, for ordi-
nary air could not furnish the 24 to 28 per cent lethal at one at-
mosphere, the 48 to 56 per cent lethal at a half-atmosphere, etc.
This is, in fact, what the numerous experiments listed in Chapter
I showed us.
1 have made a good many experiments upon animals of different
species, from which it appears that the value of the lethal tension
of carbonic acid varies according to the species.
Here, for example, are two experiments on rats:
Experiment DXCVI. August 5.
Rat placed at 3 o'clock in the small Seltzer water receiver, at 7
atmospheres.
Found dead at 6 o'clock; the muscles still contract.
Lungs inflated to the maximum, not retracting when the chest
was opened; gases expanded in the stomach.
Gas in the blood of the right heart, but not in the left heart.
Lethal air, CO, 4.4; O, 14.8.
CO, tension = 30.8.
Experiment DXCVII. August 19.
Rat weighing 180 gm., placed at 11:45 at 7J/2 atmospheres.
Same apparatus; dies at 2 o'clock.
Enormous expansion of the gases of the stomach.
No gas, even in the right heart.
Lethal air, C02 4; O, 14.3.
CO, tension = 30.0.
We see here that the lethal tension of carbonic acid is, for rats,
a little higher than for birds.
That is, furthermore, a general fact in mammals, as will be
proved presently by the experiments made on dogs, which experi-
ments will give in addition the explanation of the apparent irregu-
larities in the value of the lethal tension. I did not think I should
dwell on these differences from species to species; only one, which
I mentioned before,1 deserves to be recalled here, as I shall recall
elsewhere the general conclusion. This difference is that batra-
chians and reptiles find carbonic acid much more dangerous than
do warm-blooded animals. Here are some experiments to support
this important proposition. Some were made by using superoxy-
genated air at normal pressure:
898 Experiments
Experiment DXCVIII. February 13. Collared adder, placed in a
bell of 875 cc, with air with 77% of oxygen.
Dies February 21.
The air contains 13.5% of carbonic acid, and 61% of oxygen.
Experiment DXCIX. March 16. Frog placed in a bell of 400 cc,
with pure oxygen.
Dies March 23. The temperature was from 6° to 7°.
The air contains: O, 81, CO, 17.
Experiment DC. March 16. Frog placed in a bell of the same di-
mension, in the same air as the preceding.
Dies March 25.
The air contains: O, 84, CO, 13.7.
For others, to the superoxygenated air there was added in ad-
vance a certain proportion of carbonic acid.
Experiment DCI. August 3. Gray lizard, placed at 4: 15 in a bell
containing 570 cc. of an atmosphere with 78.9% of oxygen, the rest
being nitrogen.
August 4. Yawns a great deal, is very uneasy; the distress keeps
increasing, and the animal dies August 6, about 2 o'clock (70 hrs.).
The temperature varied from 23° to 29°.
There is 15.7% of CO, in the bell.
Experiment DCII. August 3. Gray lizard, placed at 5:15 in a bell
containing 550 cc. of an atmosphere with 90% of oxygen and 10%
of CO,.
August 4. Still somewhat sensitive at 4 o'clock in the evening;
found dead at 9 o'clock (about 28 hours).
The temperature varied from 23° to 29°.
The air contains 16% of CO,.
Experiment DCIII. August 3. Frog placed at 5:45 under a bell of
550 cc. containing 90% of oxygen and 10% of CO,.
August 4. 10 o'clock in the morning, seems to be hardly breath-
ing. Dies at 2 o'clock (lived 20 hours). The temperature of the lab-
oratory varied from 23° to 29°.
There is 17% of CO, in the bell.
For others the experiment was made in compressed air.
Experiment DCIV. July 28. Temperature 22°. Two frogs are
placed at 3 o'clock in the small Seltzer water receiver ,and subjected
to a pressure of 5 atmospheres.
Nothing special during the two or three days following.
August 1. 1 o'clock. Are evidently very sick.
Die about 3 o'clock.
The air contains 3.2% of CO,; the tension therefore is 3.2 x 5 = 16.
And so, by one or another of these multiple methods, we see that
the lethal tension of carbonic acid for reptiles varies between 13.5
Action of Carbonic Acid 899
and 17, that it is from 24 to 28 for sparrows, and that it reaches
and passes 30 for mammals.
2. The Lethal Concentration of Carbonic Acid in the Blood.
In the experiments the report of which follows, I tried first to
determine the lethal concentration of carbonic acid, not in the
exterior medium, but in the blood; next, to ascertain the relations
which exist between the increasing amount of this gas in the air
in which the animal is confined, and the quantity in the blood.
Evidently these experiments could be made only on dogs and I
could not try in practice to keep them in closed vessels in com-
pressed air. I therefore had to use the method of respiration in
superoxygenated air at normal pressure.
The set-up of the apparatus was very simple. The animal, which
was securely fastened, was forced to breathe either through a
tightly closed muzzle or directly through the trachea into a very
large rubber bag slightly inflated with oxygen. A small opening
permitted us to draw air samples at various intervals, taking great
precautions that the sample might represent the average composi-
tion of the air in the bag.
Let us now consider the report of these experiments:
Experiment DCV. February 14. Dog weighing 6.5 kilos: sick, its
pneumogastric having been cut 4 days before.
3 o'clock. Placed a tube in the trachea. Caused to breathe into
the rubber bag in which air is introduced. After 10 minutes, I draw
70 cc. of blood from the femoral artery .... A
Removed to free air.
3:35. Caused to breathe into the bag, which then contains a mix-
ture with 94% of oxygen. After 15 minutes, drew 70 cc. of blood . . . B
5:15. The animal draws deep breaths. Drew 44 cc. of blood . . . . C
9 o'clock. The eye is hardly sensitive; 15 to 16 respirations, in
groups of three, like those of tortoises; rectal temperature 27°.
The gas of the bag contains CO. 28; 02 60; C02 + O* = 88; there
has very evidently been absorbed a quantity of oxygen corresponding
to 6%.
I draw 37 cc. of blood, which comes with difficulty . . . . D
I let the animal breathe in the open air.
A (air) contains per 100 cc. of blood O, 16; CO, 29.5
B (oxygen) contains per 100 cc. of blood O, 18.4; CO, 20.6
C contains per 100 cc. of blood O, 17.5; CO. 50.1
D (CO,: 28; O,: 60.) contains per 100 cc. of blood O, 17.9; CO, 68.4
At 10 o'clock, the animal is still breathing in the same way, and
at the same temperature.
Found dead the next day.
Experiment DCV I. February 16. Very sturdy dog, weighing 15
kilos.
900 Experiments
Tube in the trachea; carotid artery exposed.
2:40. Caused to breathe into a bag containing about 30 liters of air;
at the end of 3 minutes, I draw 50 cc. of blood .... A
Allowed to breathe free air.
2:50. Again adjusted to the rubber bag, which contains 35 liters
of a mixture with about 90% oxygen. At 3 o'clock, drew 50 cc. of
blood evidently redder . . . . B
4:05. Respiration becomes deeper; took air from the bag, which
contains 21.4% of CO.; drew 50 cc. of very red blood . . . . C
4:35. Rectal temperature 35°.
5:25. Rectal temperature 33°; at 5:30, took 50 cc. of blood . . . . D
5:45. Took from the right heart, through the right jugular, 30 cc.
of very red blood . . . . E
5:50. Drew air from the bag, which contains CO, 37..3; 02 48.8.
A little air probably entered the heart, for the dog is seized by
trembling, convulsions, rigor; it is unfastened.
6:15. Rectal temperature 34°.
At 9 o'clock in the evening, is quite recovered; survives.
A (air) contains per 100 cc. of blood 02 21.0; CO= 43.5
B (oxygen) contains per 100 cc. of blood O^ 22.4; C02 43.9
C (02 for 1 hr. 15 min.: C02 21.4) contains per 100 cc. of blood
Os 22.0; CO= 89.0
D (02 for 2 hrs. 35 min.: CO. 35) contains per 100 cc. of blood
O. 19.9; CO= 87.2
E (venous blood, CO, 37.3; 02 48.8) contains per 100 cc. of blood
02 16.5; CO= 82.3.
Experiment DCVII. March 1. Large dog; muzzle.
While it is breathing in the open air with extraordinary rapidity,
I draw 70 cc. of blood from the femoral artery .... A
And from the vein, 40 cc A'
3:45. Caused to breathe into a bag full of oxygen.
3:50. Venous blood from the femoral. 40 cc B'
3:55. Gas from the bag . . . . x
3:58. Arterial blood, 40 cc B
5:25. 30 or 40 calm respirations per minute; rectal temperature 37°;
took 40 cc. of arterial blood . . . . C
The air of the bag contains CO, 32.8; 02 53.3 . . . . y
At 6 o'clock, the animal is very sick; we inject carbonic acid care-
fully into the bag through a small orifice, taking pains by agitation
of the bag to obtain a mixture as perfect as possible.
About 7 o'clock, it becomes evident that the animal is about to
die; we stop injecting the acid; rectal temperature 36°. The animal
breathes several times more. During the last respirations, I draw with
difficulty 47 cc. of very dark blood from the right heart . . . . D'
Drew next, with just as much difficulty, from the left carotid 40
cc. of very red blood . . . . D
Immediately after, took gas from the bag . . . . z
I immediately place a tube in the trachea and collect under water
the air from the lungs, opening the thorax. It contains per 100: CO-
60.8; O, 18.8.
p2
CO,
24.8
19.5
10.0
29.0
23.4
33.6
11.9
31.3
66.7
17.5
79.5
4.4
73.3
Action of Carbonic Acid 901
Summary of the Experiment
A (free air; respirations very rapid; arterial blood)
A' (free air; respiration very rapid; venous blood)
B (air x: O 81.8; CO, 3.8; arterial blood)
B' (air x: 02 81.8; CO, 3.8; venous blood)
C (air y: 02 53.3; CO* 32.8; arterial blood)
D (air z: 02 37.6; CO, 51.5; arterial blood)
D' (air z: O* 37.6; CO, 51.5; venous blood)
Experiment DCVIII. March 4. Dog weighing 3.950 kilos.
Placed under a glass bell of 31 liters; brought the pressure to 17
cm.; is very uneasy, sits up anxiously: oxygen admitted. I then take
the pressure to 8 cm.: same symptoms, and oxygen admitted up to
normal pressure.
The cock is closed at 2:45; the air contains 81% of oxygen.
4:05. Animal uneasy, breathing with difficulty, sitting up in the
bell, air sample taken .... a
5:30. The animal has just fallen on its side; air sample taken . . . b
6:10. Lying down, does not heed raps on the bell, seems insensible;
16 enormous respirations, very painful; took air sample . . . . c
9:30. Found dead; there has been absorption considerable enough
for the pressure to have diminished from 4 to 5 cm. in the bell; air
sample taken . . . . d
So, in summary:
Uneasy, with air a: O, 64.9; CO, 15.7.
Falls, with air b: O, 60.5; CO, 20.2.
Insensible, with air c: O, 53.8; CO, 27.0.
Dead, with air d: O, 46.3; C02 34.1.
Taking into account the diminution of pressure in the bell, we
easily calculate that there was about 1300 cc. of oxygen absorbed
without reappearing in the gaseous state as carbonic acid.
Experiment DCIX. March 8. Medium-sized dog; cannula in the
trachea; femoral artery exposed.
3:30. Caused to breathe in the bag containing air; respiration calm;
drew 50 cc. of blood from the femoral artery .... A
3:53. Caused to breathe in the bag containing about 90% oxygen.
Shows almost complete apnea: merely a few slight respiratory move-
ments. At 4: 10, drew 50 cc. of very red blood . . . . B
5:20. Forced respirations, very difficult; took air sample from the
bag; it contains CO, 9; Os 80.8. Drew 40 cc. of red blood . . . . C
6:15. Rectal temperature 33°; respirations very uneasy; eye sensi-
tive.
The air of the bag contains CO. 18; 02 70; drew 40 cc. of red blood
. . . . D
Blood A (air) contains per 100 cc. of blood: O, 18.9; CO, 36.5
Blood B (oxygen) contains per 100 cc. of blood: O, 23.0; CO, 42.8
Blood C (O* 80.8; CO, 9) contains per 100 cc. of blood: 02 24.7;
C02 60.8
Blood D (O, 70; CO, 18) contains per 100 cc. of blood: <)■-■ 17.6;
CO; 71.6
902 Experiments
Experiment DCX. March 12. Dog weighing 9 kilos. Tube in the
trachea.
Femoral artery exposed.
2:20. Breathes air from the rubber bag, from two to three minutes;
respirations very calm; drew 45 cc. of arterial blood .... A and
35 cc. of venous blood from the lower vena cava .... A'
2:55. Caused to breathe mixture with about 90% of oxygen.
3:10. Drew 45 cc. of arterial blood redder than A .... B
Drew 35 cc. -of blood from the lower vena cava . . . . B'
3:20. Air from the bag: Os 81.7; CO, 7.9.
5:45. 16 respirations, very uneasy; 100 weak heart beats; eye lacks
sensitivity; rectal temperature 30°; took venous blood from the lower
vena cava at the level of the kidneys . . . . C
6:35. The air of the bag contains CO, 32.5; O, 55.
6:45. 12 respirations; pulse 87; rectal temperature 28.5°; took 45 cc.
of very red arterial blood . . . . D
Next drew from the right heart 35 cc. of blood . . . . D'
Was not dead at 7:30; rectal temperature 28°. O, CO,
Blood A (air, arterial blood) 22.0 46.7
Blood A' (air, venous blood) 16.1 57.3
Blood B (about 83% of Oa and 6% of C02, arterial
blood) l 24.2 54.1
Blood B' (about 83% of O, and 6% of CO?,
venous blood) 9.8 70.6
Blood C (about 60% of O,, venous blood) 6.7 73.1
Blood D (about O, 53%; CO, 33%, arterial blood) ___18.0 93.8
Blood D' (about O, 53%; CO? 33%, blood from the
right heart) 12.3 101.4
The next day, the animal having died during the night, the stom-
ach is much distended by gases which contain 50% of CO? and 5%
of oxygen.
The air of the bag contained O, 50.6; C02 34.8; that of the lungs:
O, 23.5; CO? 57.7.
I take 45 cc. of urine from the bladder, and put it into the pump
for the extraction of gases, in which there is already a little sulphuric
acid diluted and thoroughly cleared of gas. I thus find that 100 cc.
of urine contains 106 cc. of carbonic acid.
Experiment DCXI. April 17. Dog weighing 9 kilos; tube in the
trachea.
11:05. Caused to breathe into the bag containing 28 liters of
oxygen.
No apnea visible.
11:20. Rectal temperature 37.5°.
3:05. Eye insensitive; respiratory rate 10; pulse 64, rectal tem-
perature 30°.
3:45. Pulse 51, 6 respirations; 29°.
4:05. Pulse 48, 1 respiration every 2 minutes.
4:15. Blood drawn from the right heart, 50 cc, fairly red .... A
4:40. Pulse 45; respirations every 2 or 3 minutes; temperature
27.8°.
Action of Carbonic Acid 903
4:50. The heart is still beating; no respiration for about 10 min-
utes.
Drew 50 cc. of blood from the left heart, not very red . . . . B
5 o'clock. The heart has not been beating for several minutes;
drew 50 cc. of very dark blood from the right heart . . . . C
5:15. The air of the bag contains C02 45.4; CL 39; this composi-
tion could not have changed perceptibly since death, by endosmosis,
for at 6:45, I find in it 44.6% of carbonic acid.
A. (right heart; breathing oxygen for 5 hrs. 10 min.) contains
O, 16.6; CO, 101.4.
B. (left heart; 02 39; CO, 45.4) contains O. 10.8; CO 116.6.
C. (right heart; O, 39; CO, 45.4) contains O, 0.7; CO. 120.4.
Experiment DCXII. March 15. Temperature 13°. Young bitch,
weighing 8.5 kilos.
Vaginal temperature 39°.
2:25. Caused to breathe through the trachea into the bag contain-
ing 40 liters of air with 83% of oxygen.
Respirations extremely rapid.
2:30. Took 25 cc. of arterial blood from the carotid; pulse then
was 100; the blood is extremely red .... A
2:55. 72 deeper respirations; vaginal temperature 36.1°.
3:05. Took air from the bag . . . . x
3:07. 60 respirations, quite deep; temperature 35°; took 25 cc. of
arterial blood . . . . B
4:04. 56 respirations; temperature 31°; air from the bag . . . . y
4:06. 25 cc. of blood, very red . . . . C
4:20. Respirations 44; pulse 51; temperature 30°.
4:50. Respirations 28; pulse 32; urine.
5:15. Respirations 20; pulse 24; temperature 27°.
5:25. Respirations 16; pulse 16; temperature 26.5°; one eye insen-
sible; still a little sensitivity in the other.
5:32. Took 15 cc. of carotid blood, very red . . . . D
5:38. Temperature 25°; respiration in the bag stopped, sample of
the air taken . . . . z
After a few minutes, the animal, which still lacks eye sensitiv-
ity, is seized by rigor in the legs and neck, with a certain uneasiness
in the limbs; it is unfastened. It then makes slow and languid move-
ments like those of a marmot waking up.
6:20. Animal calm; respirations 24; pulse 32; temperature 25°. I
draw 25 cc. of very red blood, then I take out the tracheal tube . . . E
The next day, the animal is perfectly recovered; its vaginal tem-
perature has risen to 40°. Survives.
Summary of the experiment: O,
Blood A (83% of oxygen) __^ 24.7
Blood B (air x: O^ 71.6; CO, 13.3) 23.4
Blood C (air y: 03 61; CO, 21.5) 22.6
Blood D (air z: O, 55; CO, 29.6) 20.3
Blood E (40 minutes after, breathing free air) 23.0 40.6 25'
CO?
Temp.
27.5
39°
51.1
35°
69.5
31°
72.3
25°
904 Experiments
Experiment DCXIII. March 19. Temperature 18°. Terrier bitch
weighing 9 kilos.
2:25. Tube placed in trachea; vaginal temperature 38°.
2:32. Caused to breathe into a bag containing 40 liters of air with
89.4% of oxygen.
Respirations extremely rapid.
2:43. Drew from the carotid 25 cc. of moderately red blood .... A
100 respirations, pulse 108, temperature 37.5°.
3:10. Took sample of air from the bag .... a
3:13. Drew 25 cc. of blood . . . . B
3:20. Respiration 36; pulse 76; temperature 37°.
3:38. Respiration 36; pulse 72, irregular; temperature 36.8°, urine;
sample of air from the bag . . . . b
3:48. Temperature 35.9°.
4 o'clock. Respiration 36; a cardiometer placed in the carotid
oscillates from 11.5 cm. to 19 cm.
4:10. Temperature 35.2°; took sample of air from the bag . . . . c
4: 18. 25 cc. of blood . . . . D
4:30. Temperature 34.5°; legs insensible, eye still sensitive; respi-
ration 56; pulse 72.
4:59. Temperature 33.5°; sample of air from the bag . . . . d
5:05. Absolutely without sensation except in the eye.
5:20. Respiration 68; pulse 80; temperature 32.8°; air from the
bag . . . . e
5:35. Temperature 32.2°.
5:45. Air .... f
5:48. Respiration 52, somewhat irregular; pulse 58, very weak;
temperature 32°; 30 cc. of blood . . . . G
The cornea becomes insensible; the conjunctiva still retains some
sensitivity.
6 o'clock. Respiration 44; pulse 44; temperature 31.2°.
6:10. 25 cc. of blood . . . . H
The bag is removed, after a sample of air for analysis has been
taken . . . . g
After a few respirations in the open air, the animal displays
rigor, which lasts only a short time. When placed on the floor, it
twists slowly, without apparent consciousness.
I remove the tracheal tube.
About 6:30, consciousness returns very clearly. At 7 o'clock,
when stimulated, stands up, and tries to walk.
The next day, quite recovered; survives. 02
Blood A (Air with 89.4% of oxygen) 25.5
Blood B (Air a; 02 78.4; CO, 8.7) 23.7
Air b; O, 71.2; CO, 14.8 ___
Blood D (Air c; O, 66.0; CO, 19.4) _ 22.9
(Air d; O, 58.4; CO, 27.3) _
(Air e; O, 53.3; CO. 32.1) _ __
Blood G (Air f; O, 50.4; CO, 34.9) ____ 18.3
Blood H (Air a; O, 47.0; CO, 38.1) 17.2
CO,
Temp.
28.9
38°
52.6
37°
36.8°
72.2
35°
33.5°
32.8°
72.6
32°
82.8
31.2°
Action of Calbonic Acid
905
Experiment DCXIV. Dog weighing 7.7 kilos. Temperature 16°.
10:30. Placed a tube in the trachea. At 10:45, its rectal temper-
ature is 38.2°.
11:35. Caused to breathe in the bag containing 40 liters of air . . a
11:43. Took 28 cc. of carotid blood .... A
12:45. Respiration 60, uneven; pulse 120; temperature 38.1°; took
air .... b
1:50. Took air .... c
Respiration 40, uneven; pulse 96; the animal is almost insensible.
2:25. Respiration 36; pulse
sensitive.
2:55. Respiration 30; pulse
temperature 31°; eye not very
double; temperature 29.8°; took
air . . . . d
3:23. Took air .... e
3:25. Respiration 28; pulse 60; temperature 28.8°; took 26 cc. of
blood . . . . B
3:45. Respiration 28; pulse 52; temperature 28.2°; carotid pressure
oscillating from 12 to 14 cm.; eye still slightly sensitive.
4:05. Respiration 20; pulse 44; temperature 27.8°; eye still some-
what sensitive; took air . . . . f
4:37. Eye lacks sensitivity; respiration 20; pulse 43; temperature
27°; took air . . . . g
5:05. Respiration 22; pulse 48; temperature 26°; took air . . . . h
5:21. Temperature 25.2°.
5:35. Respiration 4; pulse 40, very weak; temperature 25°; took
air .... i
5:50. Temperature 24.5°.
5:55. Respiration 3; pulse 36; temperature 24°; took blood from
the left heart with the cannula; very red . . . . C
6:15. Respiration 2; pulse 36; temperature 23.5°; took air . . . . j
The respirations become more and more rare, then cease some
minutes before the heart. The latter ceases at 6:35; temperature 23°.
6:45. I take blood from the left heart; it is very dark . . . . D
Also took air from the bag . . . . k
The sciatic nerve still causes the muscles to contract at 7:25.
The table below gives the results of the experiment:
Oxygen
of the bag 70.5
C02 5.2
A
O- of arterial
blood —
CO* 61.8
Rectal Temp. __38.2°
Respirations —
Pulse —
I b
d | e | f | g | h | i | j t k
58.6 | 47.9
14.4 | 24.3
42.7
28.6
39.7
30.4
IB
37.1 | 34.8
32.5 | 33.9
I I
34.9
33.9
38.1
60
120
| 29.
I 30
166
| 18.7 | —
I 90.5 | —
| 28.8 | 27.8 | 27
I 28 | 20 | 20
| 60 | 44 | 43
34.2 | 33.7 | 32.5
34.2 | 35.4 | 35.4
| C D
I
- | 18.2 0.0
-| 103.6 106.7
| 25 | 23.5 | 23
I 4 |2 |0
I 40 | 36 |0
906 Experiments
Experiment DCXV. March 26. Temperature 14°. Mastiff, very
sturdy, weighing 16 kilos.
At 11 o'clock, placed a wide tube in the trachea: the animal
struggles, breathes with very great rapidity, then falls, after a series
of unusual hasty respirations, into a state of complete apnea which
lasts a minute.
11:25. Caused to breathe into a bag containing 60 liters of super-
oxygenated air .... a
Immediately shows a slight apnea which lasts 15 seconds; tem-
perature 37.6°.
11:40. Took 25 cc. of very red blood A
11:57. 21 deep respirations; pulse 152; temperature 37.3°.
12:30. The animal has been struggling for a quarter of an hour;
took air .... b
12:35. Temperature 35.8°; urine; took very red blood . . . . B
12:45. Respiration 43; pulse 100; temperature 35°.
12:50. Arterial pressure varies between 13 cm. and 15 cm.
1 o'clock. Respiration 40; pulse 92; temperature 33.8°.
1:34. Respiration 38; pulse 88; temperature 32.2°; took air .... c
1:40. Arterial pressure varies from 14 cm. to 16 cm.
2:05. Respiration 36; pulse 72; temperature 31.2°; took blood . . . C
The animal is unfastened; the ends of his toes can be squeezed
and his skin cut, without causing the slightest sign of pain, the slight-
est movement, the slightest change in respiratory rhythm. However,
the eye is sensitive.
2:30. Respiration 28; Pulse 60; temperature 30.8°; took sample
of air . . . . d
3 o'clock. Respiration 24; pulse 56; temperature 30°.
3:15. Eye lacks sensitivity; took sample of air . . . . e
3:18. Respiration 20; pulse 48; temperature 29.5°; drew 25 cc. of
carotid blood, very red . . . . D
3:30. Arterial pressure varies from 12 cm. to 14 cm. with occa-
sional extremes of 11 and 15 cm.
4 o'clock. Respiration 16; pulse 32; temperature 28.5°; took sample
of air .... f
4: 10. Took 25 cc. of very red blood . . . . E
4:30. Respiration 8; pulse 28; temperature 28°.
4:45. Respiration 8; pulse 28; temperature 28°; pressure of 8 to
10 cm.; took sample of air . . . . g
5:15. The animal has just stopped breathing; its last respiratory
movements were recorded by the pneumograph (See Fig. 78) ; tem-
perature 27°; the heart is still beating a little; however, blood has to
be drawn by a cannula . . . . F
Took air from the bag . . . . h
6:30. There is still a little muscular contraction after very strong
stimulation of the sciatic; nothing at 7 o'clock; duration of about 1
hour and 20 minutes.
At 11:45 and 3:45, I took arterial blood and boiled it with sulfate
of soda and charcoal to test for sugar; there were only traces of it.
The summarizing table follows.
Action of Carbonic Acid
907
<a
<~
<N
| b | c r | d I " e- • I f | |g|h
Oxygen of the I I 1 I III.'
bag 182 |66.2 | 51.7 | I 42.5 | 39.0 | 35.0 | | 32.9 | 31.8
CO, | 0 |15.5 |29.7 | 1 37.3|40.3 | 42.1 1 | 45.2 | 45.7
Oxygen of the | A B | | C I | D | | E |
blood | 21.4 | 20.7 | | 21.0 I 1 23.2 | 18.7
CO, of the | | ||
blood | 42.7 | 66.8 | | 88.7 I
Rectal
temperature |37.6° |35.8°
Respiration | 21 | 43
Pulse |- | 100
Arterial
pressure | 1 13-16
I
-| 95.4
j I I
32.2° |31.2°| 30.8° | 29.5'
38 | 36 | 28 | 20
88 | 72 | 60 | 48
I
14-161
11-151
97.5 |
I I
|28.5°| | 28°
116 | I 8
| 32 | | 28
I I
I I 8-10
9.7
114.2
27°
0
D
Experiment DCXVI. March 28. Dog weighing 11.5 kilos.
2:58. I cause the dog to breathe through a muzzle in a bag in
which there has been left the air remaining from the dog of the pre-
ceding experiment. This air still contains 40% of carbonic acid.
The dog then has a respiratory rate of 20; pulse 132; I have just
taken 25 cc. of blood from its carotid, before adjusting the bag .... A
3 o'clock. Respiration 33; pulse 108; then suddenly the respira-
tion is speeded up remarkably, and rises to 168.
3:03. Appears insensible; the skin of its leg is cut and its toes
are squeezed without any sign of sensibility.
3:05. The pressure in the carotid varies between. 19 and 23 cm.;
I take 25 cc. of carotid blood B
3:06. Respiration 24, very deep; the diaphragm not acting ,the
hollow of the stomach is flattened at each inspiration; pulse 180.
3:12. Legs absolutely lacking sensitivity; the eye is sensitive; the
pupils contract in the light; but squeezing the toes causes no change
either in the state of the pupils or the arterial pressure.
3:17. Respiration 22; pulse 126; arterial pressure from 15 to 20
cm.; temperature 39°.
3:25. Respiration 24; pulse 104; temperature 39°; eye almost lack-
ing sensitivity.
3:26. I remove the bag and allow the animal to breathe the free
3:28. Respiration 44; deep; pulse 165.
3:30. Sensitivity in the legs restored.
Put down on the floor, cannot stand up, and shows signs of rigor.
3:50. Begins to stand up, tries to walk, but shows a peculiar
type of movement, turning towards the left, with its hind part on
the floor.
The head is turned, the left ear lowered, the left pupil dilated;
nystagmus of both eyes.
These phenomena last about ten minutes, gradually lessening;
then the dog recovers completely.
908 Experiments
Blood A (at the beginning) contained 19.1 of oxygen and 44.8 of CO,.
Blood B (insensibility) . . . contained 18.0 of oxygen and 81.2 of CO,.
The, air of the bag, after the experiment, contained per 100:
CO, 43.6; 02 23.1.
Experiment DCXVII. December 22. Bitch weighing 12.5 kilos.
At 4:50, the animal is forced to breathe through a muzzle into
a bag containing a mixture of CO, 20%, oxygen 60%, nitrogen 20%.
Before the experiment, the animal had a respiratory rate of 20,
pulse 80; the arterial pressure oscillated from 16 to 18 cm.; its tem-
perature was 38.5". I took 20 cc. of blood from its carotid A
At the beginning of respiration in the bag, the animal took a
few very deep breaths, but soon became calm.
5 o'clock. Quite sensitive everywhere; 44 deep respirations; the
pressure is 18 to 20 cm.
5:30. Sensitivity when the paws are pinched is somewhat
blunted; respirations 36; pulse 64; pressure from 14 to 17 cm.
5:40. I take 20 cc. of arterial blood B
5:48. Sensitivity much dulled, even when the sciatic nerve is
stimulated; eye sensitive.
6 o'clock. Respirations 28; pulse 80; temperature 36°.
The insensibility is making progress.
6:30. Respirations 36; pulse 100; temperature 34.5°.
Completely insensible to the piniching of the paws and the ears
and the electrical stimulation of the sciatic nerve. The eye is per-
haps a little sensitive yet.
The arterial pressure oscillates between 11 and 17 cm.; I draw
air from the bag and 25 cc. of arterial blood C
6:37. I unfasten the animal, remove the muzzle, and place the
animal on the floor. It is almost immediately seized by a great at-
tack of tonic, then of clonic convulsions, much like those of phenol.
These convulsions diminish little by little. 25 minutes later, the
animal begins to stand up, but it is weak and tottering.
7:20. Temperature 35°. The animal is stronger and more sensi-
tive.
The next day it is quite well.
Blood A (outside air) contained. ....... Oa 22.5; CO, 39.5
Blood B (beginning of insensibility) 02 22.5; CO, 68.2
Blood C (complete insensibility; air CO, 34.4; 02 43.8) O, 21.6; CO* 77.0
Experiment DCXVIII. December 26. Dog; rubber muzzle.
Respirations 20; pulse 88; arterial pressure from 18 to 19 cm.;
temperature 39.5°.
At 5:07, caused to breathe into a bag containing a mixture of
52.8% of CO,; 36.7% of oxygen; and 11.5% of nitrogen.
Almost immediately is seized by struggling with convulsive trem-
bling, which soon ceases.
Anesthesia is complete 2 to 3 minutes afterwards; I then take
25 cc. of arterial blood .... A
5:15. Removed the bag; immediately the respirations become
deeper and more frequent.
5:18. Sensitivity has reappeared; I take 25 cc. of blood . . . . B
Action of Carbonic Acid 909
Placed on the floor, the animal totters and seems drunk; temper-
ature 39°; but it has no convulsive movements. It has wholly recovered
after 15 or 20 minutes.
Blood A (insensibility) contained ._ Oa 23.7; CO, 98.4
Blood B (sensitivity restored) contained CX 20.8; C02 31.7
The air of the bag, at the end of the experiment, contained only
52.2% of CO, and 38.5% of oxygen.
Experiment DCXIX. December 28. Dog.
Respiratory rate 48, pulse 80; the carotid pressure varies from 15
cm. to 19 cm.; rectal temperature 39°. I take 25 cc. of arterial blood . . A
At 3:30, caused to breathe through a muzzle into a bag containing
air with 40.9% of carbonic acid, with 45.6% of oxygen.
The inspirations become deeper; but there is no struggling. At
3:33, pinching the sciatic nerve gives no reaction as to sensitivity; the
arterial pressure is from 18 cm. to 21 cm., there are 44 respirations,
pulse 152. I take 25 cc. of arterial blood . . . . B
3:35. Muzzle removed. Almost immediately convulsive struggling
occurs. Sensitivity returns at 3:40, and I take 25 cc. more of carotid
blood . . . . C
The pressure is then from 14 cm. to 16 cm., and the temperature
is 39\ No delayed symptom.
Blood A (free air) contained 21.8 of oxygen and 44.6 of CO.
Blood B (insensibility complete) contained 23.2 of oxygen and 78.6 of
CO,
Blood C (sensitivity restored) contained 22.1 of oxygen and 51.5 of CO,
The preceding experiments show first that, in the cases when
they ended in death, it occurred when the respiratory medium
contained 35.4% of CO, (Experiment DCXIV), or 39% (Experi-
ment DCXI) , or 45.7% (Experiment DCXV) . These numbers dif-
fer from each other considerably, as is evident.
On the other hand, some animals survived when the air which
they were breathing already contained 34.8% of C02 (Experiment
DCX), 37.3% (Experiment DCVI). and even 38% (Experiment
DCXIII) .
Without dwelling for the moment upon these peculiar varia-
tions, let us consider what happens to the carbonic acid contained
in the blood.
In the fatal cases, the proportion of CCX contained in 100 vol-
umes of arterial blood rose to 106.7 (Experiment DCXIV), 114.2
(Experiment DCXV) and 116.6 (Experiment DCXI); in the last
case, the venous blood contained 120.4 of CO,.
On the contrary, in the experiments when death did not occur
in spite of the large proportion of carbonic acid in the air, there
was in the arterial blood only 82.8 of CO, (Experiment DCXIII),
910 Experiments
87.2 (Experiment DCVI) , and 93.8 (Experiment DCX) ; yet, in the
last case the animal died during the night.
And therefore, as one might have thought a priori, it is not so
much the tension of the carbonic acid in the outer air as its tension
in the blood that causes death. And besides, the first acts only in
causing the second.
This explains why animals which at the very outset were made
to breathe a superoxygenated air containing 40% of carbonic acid
(Experiments DCXVI and DCXIX) , or even 52.8% (Experiment
DCXVIII), did not die immediately. They had to have time to
store up in their arterial blood a sufficient quantity of C02, and
this process was carried out in two different ways: 1) by hindering
the escape of the carbonic acid of the venous blood as it passed
through the lungs; 2) by absorbing the excess carbonic acid con-
tained in the inspired air; this absorption, moreover, is proved by
Experiment DCXVIII, in which the respirable mixture, after 11
minutes of the experiment, contained less carbonic acid than be-
fore, and more oxygen.
3. The Accumulation of Carbonic Acid in the Tissues.
But the question is still more complex. It is not only in the
blood that the carbonic acid must be stored up progressively, the
tension of which in the respired air hinders its regular excretion.
The carbonic acid of the blood comes from the tissues; in the nor-
mal state, a certain equilibrium of tension is established between
the proportion of this gas which remains in these tissues, and that
which remains in the blood, after the elimination due to a regular
respiration. If some cause maintains an excess of carbonic acid in
the blood, an excess of it must remain in the tissues. The whole
organism then must be completely impregnated with this gas,
which is highly soluble.
To inform myself about this delicate point, I resorted to the fol-
lowing experimental procedure. A determined weight of the tis-
sues of the experimental animal, which had been cut into small
pieces, was placed in a measured flask, of about triple capacity.
The flask was then quite filled with a rather strong solution of
potash or caustic soda; a similar solution was kept as control in
another flask quite full and well corked; I let the whole thing stand
for twenty-four hours, shaking it quite often, and I considered
that in this length of time, the alkali had taken up all the carbonic
acid which the tissues might contain.
I then took a certain quantity of the liquid, and introduced it
Action of Carbonic Acid 911
into the receiver of the mercury pump, in which a solution of
sulphuric acid had previously been placed and purified of its gases.
The carbonic acid, immediately removed by the sulphuric acid,
was easily extracted and collected, and a very simple calculation
informed me how much carbonic acid was contained in 100 grams
of the experimental tissues.
I also subjected to the same treatment the alkali solution which
had been kept as control, because it still contained a certain quan-
tity of carbonic acid, which, of course, had to be subtracted.
This very simple method, for which I claim no accuracy in the
decimals, seems to me to give sufficiently exact results; it has the
great advantage of not requiring complicated equipment, and of
enabling me to complete a large number of comparative experi-
ments easily.
Experiment DCXX. March 5. Dog of Experiment DCVIII, which
died the day before in a bell filled with oxygen.
80 gm. of muscles, 80 gm. of liver, 70 gm. of brain, 35 gm. of
kidneys are placed in flasks of suitable size, which were then filled
with a potash solution.
The next day, the liquids subjected to analysis, as has just been
explained, show that:
100 grams of muscles contained 42 cc. of carbonic acid.
100 grams of brain contained 26 cc.-of carbonic acid.
100 grams of kidney contained 62 cc. of carbonic acid.
100 grams of liver contained 64 cc. of carbonic acid.
Experiment DGXXI. March 21. 7 o'clock: muscles of the dog of
Experiment DCXIV, which had died at 6:45; 100 gm. are placed in a
flask with 477 cc. of a potash solution.
March 23, at 2 o'clock, analysis shows that these 100 gm. contained
66 cc. of CO,.
Now the tissues of an animal killed by true asphyxia, that is,
by lack of oxygen without increase of carbonic acid, contain a much
smaller proportion of this gas.
Example:
Experiment DCXXII. April 4. 7 o'clock in the evening. Muscles
of the dog in Experiment CLXXXVIII, which died at 6:45, exhaust-
ting the oxygen of a bag full of air, with a solution of potash. 100 gm.
are placed in 430 cc. of a solution of potash.
April 5, at 9 o'clock, these 100 gm. have released 13.2 cc. of CO,.
Even when animals have died simply in confined air, and when
the carbonic acid has not been removed as it was formed, we find
that their tissues contain very little carbonic acid. I think I should
912 Experiments
report here the experiments which prove this assertion, from which
I shall draw conclusions of another sort when I discuss asphyxia:
Experiment DCXXIII. March 11. Dog died at 2:20 in a bell filled
with air at a pressure of 43 cm.
At 4 o'clock, 80 gm. of muscle and 30 gm. of kidney are placed in
potash solutions.
March 13. We find, by the procedure described above, that 100 gm.
of muscle contain 12 cc. of CO,; 100 gm. of kidney contain 35 cc.
Experiment DCXXIV. March 5. 7 o'clock. Dog, which died at 6: 15
(Experiment DCXXXVIII), asphyxiated in compressed air.
100 gm. of muscle immersed in 900 cc. of potash solution.
March 6, 10 o'clock in the morning. These 100 gm. contained 22
cc. of CO,.
Experiment DCXXV. March 7, 5:30. A. Dog which had died at 5
o'clock (Experiment DCXXXIX), asphyxiated in compressed air.
B. Dog killed the day before at 5 o'clock by sectioning of the
medulla.
100 gm. of muscles of each animal are immersed in 500 cc. of
potash solution.
March 8, 3 o'clock. We find that the 100 gm. of A contained 23
cc. of CO?, and those of B 19 cc.
Experiment DCXXV I. March 10, 6 o'clock. Dog which was killed
by asphyxia at 5:20 (Experiment DCXL).
100 gm. of muscle placed in 585 cc. of potash solution.
March 11, 5 o'clock. 24.8 cc. of carbonic acid given off.
In other experiments, in which I analyzed the whole body of
sparrows which had died under various circumstances, I obtained
results which were quite similar:
Experiment DCXXVII. April 24. Sparrow which had died during
the night at 10 atmospheres of air.
The next day, the entire body (13 gm.), with the skin removed,
is placed in the potash solution (110 cc).
We find thus that 100 gm. of such an animal would have set free
40 cc. of carbonic acid.
The following experiment is very noteworthy in this connection:
Experiment DCXXVIII. March 18. Sparrows which died under the
following circumstances:
A died at 6 atmospheres of air (lethal air: 02 16.6; CO, 3.1)
B died at 34 cm. in superoxygenated air (lethal air: 02 12.9; C02 52.4)
C died in the air (lethal air: O, 4; CO, 14.6)
D died in the air, at 38 cm. (lethal air: 02 8.2; CO, 11.6)
These sparrows are immediately skinned, I cut off their heads,
feet, and the ends of their wings; the bodies, cut in pieces, weigh
from 20 to 22 gm. I place them in similar solutions in similar flasks.
Action of Carbonic Acid 913
The next day we find that the whole bodies furnished, if pro-
portioned to 100 gm.:
A (killed by carbonic acid) 33 cc. of CO:
B (killed by carbonic acid) 36 cc. of CO.
C (died of asphyxia, at normal pressure) 17 cc. of CO.
D (died of simple lack of oyxgen, at Mj atmosphere __0 cc. of CO.
We now understand the phenomenon in its entirety and its
simplicity. When an animal breathes in a confined medium in
which it will not lack oxygen, the increasing tension of the carbonic
acid which it excretes maintains in its arterial blood a proportion
of this same gas, which also increases. Since a similar equilibrium
is established between the blood and the tissues, in which the true
source of the carbonic acid exists, this gas is gradually stored up
in the whole organism. From this fact arise general disturbances,
the symptoms of which we shall presently discuss in detail.
Under these conditions, the blood is finally burdened with an
enormous quantity of carbonic acid; we have found as high as
116.6 volumes of it per 100 volumes of arterial blood and 120.4 per
100 volumes of venous blood. This last proportion is approaching
saturation. This saturation, which must vary from one blood to
another, is, in fact, approximately determined by the following
experiments, rather rough no doubt, but which can give us a gen-
eral idea sufficient for our purpose.
Experiment DCXXIX. February 22. Temperature of the laboratory
14°. Defibrinated dog blood.
I place 100 cc. of it in two test tubes inverted over mercury, and
then add to each one 200 cc. of carbonic acid. Energetic repeated
shaking; immediate and considerable absorption; much foam. Left
the two test tubes in the ambient temperature.
The next day, shaken again. 3 hours afterwards, made the anal-
ysis by means of the gas pump.
The extraction and analysis give the following results (gaseous
volumes reduced as usual to 0°):
One of the bloods contained CO, 123 cc; O, 16.6.
The other blood contained CO, 132 cc; O, 11.0.
Experiment DCXXX. March 10. Defibrinated dog blood. Temper-
ature of the laboratory 15°. Pressure 764 mm.
100 cc. are placed at the bottom of two flasks, through which
passes a current of carbonic acid for 24 hours. One of the flasks is
immersed in water at 41°.
We find thus that
The blood at 15° contains 177.6 cc of CO,.
The blood at 40° contains 138.4 cc. of CO;.
914 Experiments
After blood comes urine, which, as Experiment DCX showed,
may contain as much as 106 volumes of CO, per 100 volumes of
liquid.
Finally, the tissues in analysis show that their C(X content is
proportionate to the amount of blood they contain; Experiment
DCXX is quite characteristic in this regard; the kidneys and the
liver, which are very vascular organs, contained per 100 volumes
62 and 64 volumes of CO.,; the muscles had 42, the brain only 26.
The combined experiments made on the muscles of dogs or the
entire bodies of sparrows seem to show that from the bodies of
animals killed by carbonic acid one can extract about 40% of its
volume of this gas; on the other hand, they give us the idea that in
the normal state there exists there only about 10% to 15%. It
would then be about 25% to 30% of the total volume of the animal
which would represent the quantity of carbonic acid formed and
not exhaled during the stay of the animal in closed vessels. Now
Experiment DCVIII shows us definitely that a dog weighing 3.950
kilos removed from the superoxygenated medium in which it died
about 1300 cc. of oxygen, which must have been transformed into
carbonic acid and remained in its blood and tissues.
These results, we see, agree very well, but we must not at-
tribute to them extreme accuracy: from a third to a half of the
volume of the body seems to be the quantity of carbonic acid re-
tained in the tissues by an animal before dying from the action of
this gas.
This explains why, as I saw in the early experiments, the details
of which it would be useless to report here, if a dog is caused to
breathe oxygen contained in a bag of small dimensions, the animal
absorbs all the gas from the bag and then dies from simple lack of
air. All the oxygen of the bag has remained in the tissues in the
form of carbonic acid.
4. Symptoms and Mechanism of Poisoning by Carbonic Acid.
Now that this important point is established, we should study
the symptoms and mechanism of this poisoning by gradual ab-
sorption of carbonic acid in all the tissues.
Let us first consider the progressive course of the change in the
superoxygenated air which the animal is breathing. The graphs
of Figure 75, which express the results of Experiment DCXV, show
us very clearly what is taking place.
On the horizontal axis are marked in hours the time elapsed
Action of Carbonic Acid
915
since the beginning of the experiment; on the vertical axis, the
percentage of the gases contained in the bag.
We see very clearly that the consumption of oxygen and the
production of carbonic acid are not proportional to the time elapsed.
Fig. 75 — Death by carbonic acid; changes in the air of the bag.
DCXV.)
(Exp.
The longer the experiment lasts, the more the value of these
phenomena diminishes. The intersection of the graphs with the
coordinate lines shows that there were, in percentages:
In the 1st hour 15.8 of oxygen consumed, and 15.5 of C02 excreted
In the 2nd hour 14.5 of oxygen consumed, and 14.2 of C02 excreted
In the 3rd hour 9.2 of oxygen consumed, and 7.6 of C02 excreted
In the 4th hour 4.5 of oxygen consumed, and 4.0 of C02 excreted
In the 5th hour 4.0 of oxygen consumed, and 2.7 of C02 excreted
916 Experiments
In the last
50 min. 2.2 of oxygen consumed, and 1.7 of C02 excreted
As a total,
in 5h. 50m. 50.2 45.7
Experiment DCXIV gives similar results: there were, in fact:
In the 1st hour 11.9 of oxygen consumed and 9.2 of CO, excreted
In the 2nd hour 9.0 of oxygen consumed and 8.8 of CO, excreted
In the 3rd hour 5.9 of oxygen consumed and 4.6 of CO, excreted
In the 4th hour 5.2 of oxygen consumed and 3.3 of C02 excreted
In the 5th hour 3.7 of oxygen consumed and 2.8 of C02 excreted
In the 6th hour 0.8 of oxygen consumed and 0.4 of CO, excreted
In the 7th hour 1.5 of oxygen consumed and 1.1 of CO, excreted
As a total,
in 7 hrs. 37.0 of oxygen consumed and 30.2 of CO, excreted
So the consumption of oxygen diminishes progressively: and so,
in spite of the high proportion of oxygen contained in the arterial
blood, the chemical phenomena of oxidation slacken. It is not
surprising, therefore, to see that the temperature of the animal
drops progressively until, at the moment of death, it reaches the
values of 27.8° (Exp. DCXI), 27° (Exp. DCXV) (line 0 of Fig. 75),
and even 23° (Exp. DCXIV). In this connection I mention Experi-
ment DCX in which the temperature dropped from 39° to 25 3, and in
which, however, the animal, when returned to the free air, sur-
vived without symptoms. I shall refer later to the importance of
this drop in temperature, as a result of the decrease of the inner
combustions.
Let us now examine the gases of the blood at different moments
in the experiments. Let us take again, for example, Experiment,
DCXV, the most complete we have performed. The summarizing
table-' and lines Ox and CO- of Figure 76 show these results clearly.
We see first that in spite of the increasing proportion of carbonic
acid, both in the respired air and in the blood, the proportion of
oxygen was not much modified during the first four hours of the
experiment; not until then did it decrease progressively, although
death cannot be attributed to it, since at the last heart-beats, when
the respiration had ceased, there still remained 9.7 volumes of
oxygen in 100 volumes of arterial blood.
As to the carbonic acid, I have already mentioned the enormous
proportion which it reached at the moment of death. But the course
of its storing up in the arterial blood is not regularly progressive.
Action of Carbonic Acid
917
Fig. 76 — Death by carbonic acid; modifications in the composition of the
gases of the blood, the respiration, and the circulation. (Exp.
DCXV.)
We draw from the table following Experiment DCXV and from
the line CO2 the following figures:
In the 1st hour, the blood gained 20.0 volumes of CO._,
In the 2nd hour, the blood gained 16.8 volumes of CCX
918 Experiments
In the 3rd hour, the blood gained 11.0 volumes of C02
In the 4th hour, the blood gained 5.0 volumes of C02
In the 5th hour, the blood gained 5.5 volumes of CO,
In the last
50 minutes, the blood gained 13.2 volumes of C02
And so, except during the last hour, the CQ2 content of the
blood increased less and less quickly, whereas the animal was
being poisoned. And that is easily understood, since we have seen
that the absorption of oxygen was growing slower in the same
way, so that the production of carbonic acid in the tissues was less
and less active and its discharge into the blood less and less con-
siderable.
But in the last hour the blood suddenly acquires a considerable
quantity of CCX (See Fig. 76, line CO-) . A glance at the lines P
and R of the same figure, which express the number of the heart-
beats and of the respirations, explains this singular fact perfectly;
at the moment, in fact, the heart slowed down considerably, and
the respiratory movements, reduced to 10 and 8 per minute, ceased
for an instant: the blood must have lost less C02 in passing through
the lungs and have gained more in passing through the tissues.
Furthermore, the oxygen of the blood was consumed on the spot
and must have furnished a certain quantity of carbonic acid.
Since the carbonic acid content of the blood has as its cause
the increasing tension of this gas in the confined air which the
animal was breathing, it was interesting to determine the ratio
between these two variable values. This is easily done by com-
paring the lines C02 (which have the same coordinates) of the
two figures 75 and 76, which express the two columns C02 of the
bag and CO. of the blood in the table summarizing Experiment
DCXV.
We thus find first that when the air of the bag contained 10 %
of C02, 100 cc. of arterial blood contained 55 volumes of the same
gas, and we are led, by similar comparisons, to draw up the fol-
lowing table:
With 0 of C02 in the air, there was 40 of it in the blood.
With 10 of CO., in the air, there was 55 of it in the blood. Dif-
ference 15.
With 20 of COL> in the air, there was 70 of it in the blood. Dif-
ference 15.
With 30 of COL, in the air, there was 82 of it in the blood. Dif-
ference 12.
Action of Carbonic Acid
919
With 40 of CO. in the air, there was 95 of it in the blood. Dif-
ference 13.
With 45 of CO, in the air, there was 114 of it in the blood. Dif-
ference 19.
We see that increases in the arterial blood which do not differ
much correspond to equal increases in the respirable air; this re-
sult conforms to the laws of physics. But we should not attribute
to it too great an exactness, because important changes in the
Fig. 77 — Death by carbonic acid; relation of the respiration and the circu-
lation to the carbonic acid content of the blood. (Exp. DCXV.)
respiratory rhythm may modify considerably the quantity of car-
bonic acid contained in the arterial blood.
Let us now drop these chemical considerations and discuss the
changes which occurred in the various functions.
The number of heartbeats decreases progressively; the tables
summarizing Experiments DCXIV and DCXV show that clearly,
and line P of Figure 76 still more clearly, at least for Experiment
DCXV. If we draw up graphs with the results of this experiment,
taking for abscissae, not the time elapsed since the beginning of
920 Experiments
the experiment, as in Figure 76, but the quantity of carbonic acid
contained in the blood (Fig. 77), we see that this decrease in the
number of heartbeats follows quite regularly the increase in the
carbonic acid of the blood.
The detailed account of the different experiments shows that
the heartbeats persist after the respiratory movements have ceased;
in Experiment DCVI, the heart continued to beat for about ten
minutes.
On the other hand, we see that the blood pressure in the arteries
is modified only very slowly by the accumulation of carbonic acid
in the blood and the tissues. At the very beginning it seems in-
creased a little (Exp. DCXV and DCXVI) ; but it is still from 12 to
14 cm. at a time when there is more than 90 volumes of carbonic
acid in the blood (Exp. DCXIV) , and from 11 to 15 when there is
95 (Exp. DCXV), and even from 8 to 10 when there, are only 8
respirations to the minute, when the temperature has fallen to 28°,
and when the arterial blood contains more than its own volume of
carbonic acid (Exp. DCXV) .
Fig. 78 — Death by carbonic acid; last respiratory movements. (Exp. DCXV.)
So, in progressive poisoning by carbonic acid, the heart is the
ultimum moriens (last to die), and its beating is the last sign of
life which one can observe in the dying animal.
The number of respiratory movements decreases equally; at the
beginning of the experiment it often increases, but when the car-
bonic acid of the blood reaches a proportion above 90 volumes,
the slackening assumes considerable intensity. For Experiment
DCXV, these phenomena are easy to study in the summarizing
table and in the lines R of Figures 76 and 77. In Experiment
DCXIV, during the last hour of life, there were only 2 to 4 respira-
tions per minute; at the very end, there was only one every two
or three minutes, and in Experiment DCVI, one every three or
four minutes. At the end, their depth decreased like their number,
Action of Carbonic Acid 921
and the tracing in Figure 78 which was made by the pneumograph
(Exp. DCXV), shows that the cessation of the respiratory move-
ments took place without a last sigh: this in itself as I proved
elsewhere', indicates that carbonic acid is not a heart poison.
During the whole duration of this progressive poisoning, the
animals remain perfectly calm. At the beginning, only a few
struggles, which soon are quieted. If the animal is unfastened
when the arterial blood contains 60 or 70 volumes of CO., it makes
no attempt to escape. Later, it becomes insensible to stimuli, to
pinching, even to electrical stimulation of the sensory nerves:
finally the eye itself becomes insensible.
This curious anesthesia deserves our attention for a few
minutes.
Let us say first that insensibility to pinching occurs long before
the animal is threatened by death. In Experiment DCVI, the eye
was insensible two hours before death, when there were still 10
respirations, and 64 heart beats, the temperature having fallen to
30 degrees; in Experiment DCXIV, the paws became insensible
more than four hours before death, and the eye two hours (respira-
tions 20; pulse 43; temperature 27°); finally in Experiment DCXV,
absolute insensibility of the paws was observed more than three
hours before death, and the eye became insensible two hours before
(respirations 20; pulse 48; temperature 29.5°).
This insensibility is very complete; stimulation of the sciatic
nerve by pinching or electric currents causes no general movement,
no change in the respiratory rhythm (Exp. DCXV) , in the arterial
pressure or the state of the pupils (Exp. DCXVI) , even when they
still contract under the direct influence of light. The eye, as I have
just said, keeps its sensitivity for a long time yet, and this sensi-
tivity disappears last in the conjunctiva (Exp. DCXIII).
Now when the eye has become absolutely insensible, the animal
is by no means in danger. If it is taken from the altered medium
and brought into the air, it always recovers (Exp. DCXII, DCXIII,
DCXVI, DCXVII, DCXVIII, DCXIX), generally after displaying
strange symptoms, to which I shall call attention presently.
If we investigate the proportion of carbonic acid in the air and
the arterial blood at which insensibility of the feet or of the eye
occurred, this is the average we obtain: insensibility of the feet
appeared when the air contained about 28% of carbonic acid,
and insensibility of the eye when the proportion rose to 35%; for
the blood, the extremes are much wider, since they vary from 72.3
(Exp. DCXII) to 95.4 (Exp. DCXV) .
922 Experiments
This complete anesthesia of the limbs, when the eye is still
sensitive, when the heart still beats frequently and strongly, and
when the animal is still so far from serious danger, naturally in-
spired the idea of a possible surgical application.
But an important difficulty appeared. In the experiments which
I have just reported, the animal itself forms the carbonic acid
which it stores up in its blood and tissues; that requires a very long
time. In Experiment DCXIII, insensibility of the paws was ob-
served only after two hours; it took more than three hours in Ex-
periments DCXIV and DCXV. Nothing would be less practical
than this long preparation, which would be a long torture. On the
other hand, and this is still more important from another point of
view, in these long experiments the temperature had dropped sev-
eral degrees at the time when insensibility of the paws appeared,
and that might have serious consequences for the patients.
I then asked myself whether I could obtain results similar to the
preceding ones by making the animals breathe a more or less rich
mixture of carbonic acid and oxygen early in the experiment. I
did this in Experiments DCXVI, DCXVII, DCXVIII, and DCXIX.
When the mixture to be breathed contained 207c of carbonic
acid (Exp. DCXVII), insensibility appeared only after IV2 hours,
at which time the temperature had dropped 4°, the respirations
numbered 36, and the pulse rate was 100; the arterial blood then
contained 77 volumes of CCX. But with 40% of C02 (Exp. DCXVI,
DCXIX) insensibility occurred after 3 or 5 minutes, of course
without a change in the temperature, the heart having singular
strength, (19 to 23 cm., Exp. DCXVI; 18 to 20 cm., Exp. DCXIX)
greater than in the normal state: the arterial blood contained 78.6
volumes (Exp. DCXIX) or 81.2 volumes (Exp. DCXVI) of carbonic
acid.
Finally, with a mixture containing 52.8% of C02, insensibility
was almost instantaneous, and the arterial blood was laden with 98.4
volumes of CO, (Exp. DCXVIII) .
These last results show that the surgical use of carbonic acid,
in a proportion of about 40%, the rest of the gas being nearly pure
oxygen, might give good results, and would not at all affect arterial
pressure, as do the compounds of carbon and hydrogen and the
chloro-carbon compounds of hydrogen.
But this proportion of carbonic acid in the respirable medium
must not be much exceeded. I showed in 18644 that if two new-
born rats were placed, one in carbonic acid, the other in nitrogen,
the heart of the latter continues to beat more than a quarter of an
Action of Carbonic Acid 923
hour, whereas the heart of the former stops in 2 or 3 minutes. But
these conditions are quite different from those of my present ex-
periments. Here we are dealing with carbonic acid slowly formed
by the organism itself, and not with a flood of acid reaching the
blood of the left heart suddenly.
There is one last point left to study. When the animal is
brought back to free air, even though its blood and its tissues are
laden with an enormous proportion of carbonic acid, it recovers.
And so the dogs in Experiments DCVI, DCXII, DCXIII, survived,
although their arterial blood contained 73.3, 82.8, and 87.2 volumes
of C02, and the body temperature had dropped to 25° (Exp.
DCXII) .
They recover gradually; their respiration accelerates, as does
the heart; their temperature rises, and strength returns with sen-
sitivity, which reappears in 10 or 15 minutes.
But very strange nervous symptoms always appear at this time;
these are rigors with a few clonic convulsions, or slow and languid
movements, like those of a hibernating animal which is warmed
and which is awakening. That lasts a few minutes, during the
phase in which insensibility still persists.
One might think that these phenomena are due in part to the
considerable loss in temperature of the experimental animals. That
is not the case, for in Experiments DCXVI and DCXIX, in which
insensibility was obtained early by respiration of supercarbonated
air, and in which there was no loss of temperature, the same symp-
toms appeared.
They are therefore related to the elimination of excess carbonic
acid; the return to its normal state of the anesthetized spinal cord
is shown by disconnected stimuli which for some minutes cause
convulsive symptoms.
We know that, according to M. Brown-Sequard, carbonic acid
is a poison which causes convulsions; the violent symptoms which
mark the end of asphyxias and quick hemorrhages are explained,
according to him, by the action of the carbonic acid accumulation in
the tissues. Long ago I replied to this theory, which, I hope will
not return for discussion today. But here, by a singular coincidence,
these convulsions, which the carbonic acid was accused of pro-
ducing, are absolutely the sign of its elimination.
I do not think that these convulsive symptoms of the return to
sensibility constitute a serious obstacle to the use of carbonic acid
by surgeons. They are surely much less terrifying than the violent
struggles which so often mark the beginning of the action of chloro-
924 Experiments
form, and which have mistakenly been named the "period of exci-
tation." And besides we might very probably avoid them by
lessening the speed of the elimination of the carbonic acid.
But while I call attention of the surgeons to this anesthetic,
which has often been considered but which has never been studied
with sufficient care, I am far from believing that the preceding
researches are precise and detailed enough to authorize immediate
application: an experimental table upon which a dog is fastened
is one thing, and the bed of a patient is another.
While trying to give myself a precise idea of the inner action
of carbonic acid, I reach the following considerations:
The excretion of the carbonic acid which is constantly being
formed in the interior of the tissues is a necessary condition on
account of the continued metabolic exchanges which give rise to it.
Here, as in so many other chemical phenomena, the product of the
reaction must be eliminated constantly so that this reaction may
maintain its maximum activity. When, through respiration in
closed vessels, under conditions specified above, the carbonic acid
is stored up in the tissues, it delays all the oxidations there, as is
proved by the rapid drop in the temperature. As for the nervous
system, if it seems affected first, that is because it is the first to
show the general effects which disturb the whole organism; and
because the spinal cord fails in its reflex functions of sensitivity
and respiration, just as it is the first to show the organic disturbances
which occur when we bleed, diminish or increase the 02 of the
blood, chill, or overheat an animal.
But when the carbonic acid is artificially brought from outside,
and when it is inhaled in a gaseous mixture, it is not the whole
organism which is affected as in the first case. The carbonic acid,
absorbed by the arterial blood in passing through the lungs, is
immediately carried by it to the nervous center, the metabolic
changes of which are therefore suddenly disturbed, delayed, and
altered: hence the anesthesia. Finally, when the proportion is
great enough in the respiratory mixture, the cardiac ganglia them-
selves are immediately affected in their metabolism and the heart
stops, paralyzed.
5. Action of Carbonic Acid upon the Lower Living Beings.
The universality of action of carbonic acid upon all tissues is
shown very clearly when we experiment upon lower animals. Long
ago, for example, I showed in my courses that frogs or new-born
mammals die sooner in carbonic acid than in carbon monoxide.
Action of Carbonic Acid 925
And that is easily understood, I said: carbon monoxide acts like
a simple hemorrhage or an asphyxia in nitrogen, by suppressing
the oxygen of the blood, whereas carbonic acid poisons the tissues
themselves. Only if the experiment is stopped before the animals
are quite dead, the frog with the C02 recovers quite quickly, but the
one with the CO dies, on the contrary, since it is definitely de-
prived of its red corpuscles.
It seemed to me interesting to try to determine the proportion
of carbonic acid dissolved in the water, which would be incom-
patible with the life of fishes. Here are the details of the experi-
ment:
Experiment DCXXXI. May 22. At 12:15. Golden carp of the same
size are immersed in flasks with stoppers, full of a well aerated water
to which have been added growing proportions of water saturated
with carbonic acid so that
A contained pure water (which holds in solution 4.4 volumes of
CO. per 100 volumes of liquid)
B contained water with 11% of C02
C contained water with 18% of CO,
D contained water with 30% of C02
E contained water with 45% of C02.
At 12:35, fish E was breathing very feebly, whereas B was breath-
ing more strongly than A.
12:45. E is on its side, very sick; D is evidently sick too.
1:05. E is dead; D, very sick; C and B are breathing with diffi-
culty; D dies about 10 o'clock in the evening.
The next day, A, B, and C are still alive.
The proportion of free C02 which is rapidly fatal is therefore
in the neighborhood of 30%. That is much above the quantities
which exist in all waters not charged with saline elements.
Carbonic acid manifests its action not only on animals, but also
on plants.
In a medium with high C02 content, green plants die rapidly,
when we prevent the light from permitting them to decompose
the dangerous gas rapidly.5
Germination is delayed and checked, when the proportion of the
gas is sufficient; the seeds themselves may be killed by it. As an
example of these facts, I quote the two experiments following:
Experiment DCXXXII. April 8. Sowed, under a large bell of 11
liters, a few seeds of barley and of cress upon well moistened paper.
The bell is filled with a mixture containing: 02 16; CO, 20; N 64.
May 2. Nothing has developed; the air of the bell contains:
02 12.9; C02 29. I leave the seeds in the open air; on May 7, some
shoots appear, and on May 20 all has sprouted well; the barley already
measures 12 cm.
926 Experiments
Experiment DCXXXIII. March 30. A. 20 barley seeds are sowed
on wet paper, under a bell of 11 liters containing 50% of carbonic
acid and 50 of ordinary air.
B. As controls, other seeds are sowed under a bell of 2.5 liters full
of ordinary air.
April 3. Evident germination in B.
April 9. The shoots in B are 3 to 4 cm. high; nothing in A. On the
seeds in B abundant mold has appeared; there is nothing in A.
April 22. There are fine shoots in B, and its air contains C02 4.4;
O, 13.6. No shoots in A, the air of which still contains 9.3 of oxygen.
A, when left in the open air, does not sprout.
And so, with 20 % to 30% of carbonic acid, there is merely sus-
pension of germination; but with 50%, the seeds are killed. And
what is true of seeds of barley is true of molds, as we see in the
very experiment which has just been reported.
It is not surprising then to see that putrefaction itself is greatly
delayed and even checked in an atmosphere laden with carbonic
acid.
That is what happened in the following experiments:
Experiment DCXXXIV. December 14. Fragments of muscles placed
in bells filled:
A, with air;
B, with almost pure carbonic acid.
January 8. A is foul, in full decay, covered with mold; B has no
odor and no mold is apparent.
Experiment DCXXXV. January 14. Fragments of muscles placed
in bells filled:
A, with air;
B, with a mixture (O, 14.4; N 54.6; CO, 31%).
January 17. The air of A now contains only 18.1 of oxygen, with
3 of CO,; it smells bad.
The air of B has not changed its composition and has no odor.
Experiment DCXXXVI. July 29. A thin slice of beef weighing 100
gm. is hung in the glass apparatus, under a pressure of 6 atmospheres,
5 of which are carbonic acid.
August 10. Decompression.
The meat has no odor; its color is rather dull. I cook it; it has
no putrid odor or taste; but its flavor is disagreeable, insipid, sweetish,
like that of meat kept in compressed oxygen.
Finally, the muscular contractility is rapidly destroyed by car-
bonic acid and very probably the same thing would be true of the
other vital characteristics.
Action of Carbonic Acid 9^7
Experiment DCXXXVII. June 4. Two feet of the same frog are
hung each at the top of a test tube:
A in air;
B in almost pure carbonic acid.
June 5. A, nerve not excitable; muscle very contractile;
B, no muscular contractility.
6. Summary and Conclusions.
We have now reached the end of this long study. It is sum-
marized in the following propositions:
A. When an animal breathes in a closed vessel, either in com-
pressed air, or in a superoxygenated air, at normal pressure, so that
it never lacks oxygen, the increasing tension of C02 in the air
maintains an increasing proportion of the same gas in the blood,
so that the carbonic acid produced within the tissues remains in
these tissues.
B. From this accumulation there results a progressive slacken-
ing of the intra-organic oxidations, and consequently, a consider-
able lowering of the body temperature.
C. The central nervous system, in this general effect upon the
organism, is the first to show that it is attacked, by the loss of
the reflex transmissions, first in the limbs, then in the eye, finally
in the respiratory center, from which death results.
D. No struggle, no convulsive movement precedes death.
The heart, though slackening its beats, retains its full strength
for a very long time, and remains the ultimum moriens (last to die) .
These two facts definitely disprove the theories which make of
carbonic acid either a poison which causes convulsions or a poison
of the heart.
E. The anesthesia produced by carbonic acid apparently de-
serves to attract the attention of surgeons again; it is complete at
the moment when the life of the animal is far from being in danger.
F. Plant life, germination, the development of molds, and putre-
faction are slowed, suspended, and definitely checked by carbonic
acid at a sufficient tension.
G. Therefore, carbonic acid is a universal poison, which kills
animals and plants, large or microscopic; which kills the anatomical
elements, isolated or grouped in tissues. And that is not at all
surprising because it is the product of universal excretion of all
living cells; its presence hinders excretion, and consequently by
interposing a terminal obstacle stops the whole series of the con-
stituent chemical transformations of life, which begin with the
absorption of oxygen and end with the discharge of carbonic acid.
928 Experiments
Subchapter II
ASPHYXIA
The researches of which I have given an account in the pre-
ceding chapters have naturally led me to the study of asphyxia in
closed vessels, in ordinary air, at normal pressure. Here, at the
moment of death, are very low oxygen tension and fairly high C02
tension; to which of the two influences is death due? Do both
have an effect?
I have already treated this question in my "Lessons on Respira-
tion" (page 525) , and basing my belief exclusively on the chemical
composition of the lethal air, I had arrived at the following
conclusions:
A. For warm-blooded animals, death occurs from lack of oxygen;
B. For cold-blooded animals, from poisoning by carbonic acid.
I was brought to consider this question from another point of
view, upon observing the modifications undergone by the gases of
the blood, and comparing them on one hand with those reported in
Chapter II, Subchapter IV, and ok che other hand, with those
which are the result of carbonic acid poisoning.
The experiments were made by the same method as in the
chapters mentioned: respiration with a hermetically closed muzzle,
or by the trachea, in a bag containing a certain quantity of air.
The report of a few experiments follows:
Experiment DCXXXVIII. March 5. Spaniel weighing 12 kilos.
5:35. Drew 40 cc. of blood from the carotid .... A
5:37. Caused to breathe -through a muzzle in a rubber bag con-
taining about 20 liters of air.
5:52. The animal, which has struggled a great deal, and which has
lost air around the sides of the muzzle, is very sick.
Took air from the bag .... a
5:55. Drew 33 cc. of very dark blood from the carotid . . . . B
6:15. The animal dies, without convulsions or rigor. With diffi-
culty I draw from the left heart blood which is beginning to coagu-
late . . . . C
Air from the bag . . . . b
Blood A (in the open air) contained 02 15.9; CO, 44.8
Blood B (air a: O, 4.8; CO, 12.1) contained O, 2.4; CO, 44.5.
Blood C (lethal air b: O, 3; CO, 15.8) contained O, 0.8; CO, 39.9
Experiment DCXXXIX. March 7. Spaniel weighing 13 kilos.
I expose the carotid and the trachea.
3 o'clock. Respirations 45; pulse 90; rectal temperature 38.5 D.
Asphyxia 929
3:05. Drew 33 cc. of blood from the carotid, moderately red ... A
3:15. Placed a tube in the trachea.
The respirations become extraordinarily rapid.
3:20. Respirations 124; temperature 38.5°; drew 33 cc. of blood
from the carotid, redder than A .... B
3:22. Placed the trachea in communication with a rubber bag con-
taining 60 liters of air.
Much struggling; respirations very frequent.
3:43. Temperature 38°.
4 o'clock. Respirations 84; pulse 96; took air and 33 cc. of blood,
not so red as A .... C and a
4:05. Very deep respirations, 56 per minute; pulse 96.
4:15. Temperature 36.5°.
4:35. Respirations 28; pulse 52, very irregular.
Temperature 36°. Air from the bag . . . . b
Cornea sensitive; drew 25 cc. of very dark blood . . . . D
4:40. Cornea without sensitivity; pupils dilated; respirations 16;
pulse too weak to be felt; temperature 35.5°.
The respirations become slower and slower, and the last takes
place at 4:46; there is no convulsion.
4:48. The heart still pumps a little blood into the carotid, and
with a cannula I succeed in extracting 40 cc. of very dark blood from
the left heart . . . . E
Then I take a sample of air from the bag . . . . c
4:55. I collect under water the gases of the lungs . . . . d
The urine, treated with sulphuric acid in the pump, gives about
15 volumes per 100 of C02.
Blood A (free air, respiration by natural channel) 02 19.8; C02 40.1
Blood B (free air, respiration very rapid, by the trachea) 02 21.5;
CO 18.3
Blood C (air a: 02 9.3; CO, 7.0) O2 14.4; CO. 32.0
Blood D (air b: 02 1.8; CO, 12.0) O. 2.1; C02 54.3
Blood E (lethal air c: O* 1.5; CO. 12.6) O, 1.2; C02 42.5
The air from the lungs d contained; 02 0; C02 14.6.
Experiment DCXL. March 10. Brach-hound, weighing 16 kilos.
Rectal temperature 39.5°.
3:15. Placed a tube in the trachea; breathes calmly.
3:20. Caused to breathe in the bag, which contains 137 liters of
air.
3:23. Respiration calm; drew 33 cc. of blood from the carotid,
moderately red .... A
3:49. Deep respirations, 58; took air from the bag .... a
3:50. Drew 25 cc. of blood, not so red as A .... B
4:05. Deep respirations, agitated, 48; temperature 37.8°.
4:12. Violent struggling; temperature 37.5°.
4: 15. Air from the bag . . . . b
4: 16. Respirations ample, 52; drew 25 cc. of blood, considerably
less red . . . . C
4:38. Air from the bag . . . . c
930 Experiments
4:40. Respirations, 48; temperature 35.5°; drew 25 cc. of dark
blood . . . . D
5 o'clock. Respirations fairly deep, 40; pulse 36; temperature 35°.
5:03. Air from the bag . . . . d
5:07. Drew 25 cc. of very dark blood . . . . E
5:08. The eye, till then sensitive, becomes insensible; the pupil
dilates.
5: 10. Respirations 6; pulse 30.
5: 15. Urine; the respirations become slower and slower and weaker
and weaker; the heart also is failing.
5:20. Died without convulsions. Took air from the bag . . . . e
Took blood from the left heart . . . . F
The urine contains 18 cc. of C02 per 100 cc. of liquid.
The sciatic nerve remains excitable by electricity until 6:40, that
is, for 1 hour 20 minutes.
Blood A (free air) contained 02 21.8; C02 42.9
Blood B (air a: 02 12.5; CO: 6.8) O2 21.0; C02 48.2
Blood C (air b: 02 7.6; C02 9.8) O. 15.4; CO. 57.8
Blood D (air c: O. 4.0; CO, 10.3) 02 6.9; CO, 58.3
Blood E (air d: <D2 2.8; CO2 14.7) O2 1.0; CO, 52.4
Blood F (lethal air e: 02 1.9; -CO, 14.7) _•__. 02 — ; CO2 50.2
Experiment DCXLI. March 28. Dog weighing 11.5 kilos; rectal
temperature 39°.
4:10. Took 25 cc. of blood from the carotid, moderately red ... A
I immediately cause it to breathe through the muzzle in the bag
which contains about 100 liters of air.
Respirations 28.
4:40. Respirations 36; pulse 92; temperature 37.5°; took air from
the bag .... a
4:41. Drew 25 cc. of blood not so red as A .... B
5:10. Respirations 36; pulse 100; temperature 36°; took air from
the bag . . . . b
5:11. Drew 25 cc. of very dark blood . . . . C
Feet still sensitive.
5: 15. Suddenly stops breathing, without convulsive struggling.
5:20. Drew 45 cc. of very dark blood from the left heart . . . . D
Took air from the bag . . . . c
The sciatic nerve is excitable until 6:30, that is, for 1 hour, 10
minutes.
Blood A (respiration in free air) contained 0= 15.7; CO. 36.5
Blood B (air a: O, 19.2; CO. 1.9) contained 02 12.8; CO. 49.3
Blood C (air b: analysis lost) contained O2 2.5; C02 53.8
Blood D (lethal air c: 02 4.3; CO. 13.1) ___contained O2 0.5; CO, 53.6
Experiment DCXLII. April 2. Young terrier, weighing 7.5 kilos;
tube in the trachea.
6 o'clock. Caused to breathe in the bag containing about 40 liters
of air.
6:01. Drew 20 cc. of very red blood; the animal remains quiet
while the blood is being drawn .... A
Asphyxia 931
6:05. Respirations 136; pulse 120; temperature 36.5°.
6:30. Respirations 50; pulse 106; temperature 35.8°; took air from
the bag .... a
6:31. Drew 20 cc. of dark blood . . . . B
The animal struggles; respirations deep and irregular; eyes and
feet sensitive.
6:45. Respirations 52; pulse 76; temperature 34.2°; took air . . . . b
6:58. Respirations 9; pulse 14; temperature 33.8°; eye lacks sensi-
tivity; took air . . . . c
And very dark blood . . . . C
7:06. Respiration has stopped; we count 60 more heartbeats, very
weak; the intestines move in the abdomen; the heart stops beating
at 7:09.
Took air from the bag . . . . d
Blood A (respiration in the open air) contained 02 14.6; CO: 46.7
Blood B (air a: O, 7.4; CO. 9.1) contained 02 9.1; CO, 52.3
Blood C (air c: O. 2.6; C02 13.3) contained 02 0.8; CO. 51.8
The lethal air d contains: O. 2.4; CO. 12.9.
[Analysis of air b not given. Translator]
I shall not dwell upon the symptoms shown by the animals the
history of which I have just reported: slowing down of the respira-
tion and of the circulation, final insensibility, dilation of the pupil,
progressive fall of temperature, these are well-known phenomena.
Besides, I have spoken of these symptoms in the chapter in which
I discussed asphyxia in closed vessels, the carbonic acid being
eliminated.
I shall merely state that the final phenomena, that is, the in-
sensibility of the eye and the dilation of the pupil, occur at the
time when there are only about 1 to 2 volumes per 100 of oxygen
in the arterial blood (Exp. DCXXXIX and DCXL) . The animal,
therefore, is then in great danger of death, since the quantity of
oxygen found in this same blood after death varied from 0.5 to 1.2.
Let us now give our attention to the progressive changes in the
confined air in which my animals were breathing. The graphs of
Figure 79 express the results of Experiment DCLX, the most com-
plete of those which we reported.
On the axis of the x's are measured the periods elapsed since
the beginning of the experiment; on the axis of the y's, the existing
proportions of oxygen, and C02, and the sum 02 + CO„ of these
two values, the variations of which sum present here, as we shall
see, a true interest.
We see that the oxygen consumption kept decreasing in pro-
portion as the asphyxia progressed; in the first hour, it was 13.3%;
m the second and last, only 5.7%. Similarly, in the first hour,
9.8% of carbonic acid was produced, and only 4.9% in the second.
932
Experiments
These data are identical with those on which I dwelt in Sub-
chapter IV of Chapter II.
I can say the same relating to the final composition of the lethal
air. The variations were, for the oxygen, from 4.3 (Exp. DCXLII)
to 1.5 (Exp. DCXXXIX), and for carbonic acid, from 12.6 (Exp.
DCXXXIX) to 15.8 (Exp. DCXXXVIII).
Fig. 79 — Death by asphyxia in a
in a closed vessel; gases
of the air. (Exp. DCXL.)
Fig. 80 — Death by asphy-
xia in closed vessels;
gases of the blood.
(Exp. DCXXXIV.)
Let us now take up the gases of the blood. Here too the accom-
panying graph (Fig. 80) (the volume of the gases was not reduced
to zero) shows the facts very clearly (Exp. DCXXXIV) .
As we know, the oxygen continues to diminish in the arterial
blood. But it does not diminish in a manner regularly propor-
tional to the time; in the first hour, in fact, we see that the propor-
tion of oxygen dropped only 6.6 volumes, whereas it fell more than
14 in the second hour.
Asphyxia
933
This agrees with what our former studies taught us. The
greater absorption of the exterior oxygen at the beginning results
in a relative persistence of the oxygen content of the arterial
blood.
If now we construct a graph (Fig. 81), taking for the abscissae
the quantities of oxygen contained in the outer air at the various
moments of asphyxia, and plotting on the ordinates the quantities
of oxygen contained in 100 volumes of arterial blood, we reach a
result which is absolutely like line Ox (dotted line) of Figure 39,
furnished by asphyxia without carbonic acid. The carbonic acid
then seems to have had no effect.
Fig. 81 — Relation between the oxygen content of the air and that of the
blood.
And as to the carbonic acid, its proportion at first increases in
the blood, as we might have expected, since it increases in the air
which the animal breathes. But suddenly it decreases, and the
curve (Fig. 80) presents a point of retrogression corresponding to
1 hour 20 minutes; and so, in the last moments of life, there is in
the blood less C02 than there was a few instants before. When I
observed this fact for the first time, I thought that acid had been
absorbed by the tissues at the moment when the heart beats very
slowly. But if we, compare the line of the CCX of the blood (Fig.
79) with that of the C02 + (X of the air (Fig. 80) , we see a similar
point of retrogression which shows that, at the precise moment
934 Experiments
when COo diminishes in the blood, it increases considerably in the
expired air, that, in a word, it leaves the animal. In all my
analyses I have found this fact, unknown until now: a glance at
the summarizing tables is enough to convince anyone.
We must not then continue to say, as was too easily admitted
a priori, that in asphyxia in closed vessels the quantity of CO,
contained in the blood keeps increasing until death; quite to the
contrary, it always diminishes in the last moments of life.
Furthermore, when the volume of air in which the animal is
asphyxiated is small, the carbonic acid diminishes in the arterial
blood from the beginning, in spite of its increase in the air. This
is shown by Experiment DCXXXVII, for example, in which
although a large dog was given only 20 liters of air, the carbonic
acid content of its blood fell from 44.8 to 39.9.
But when the carbonic acid is prevented from reaching the
outer air, as is the case with animals that are strangled or drowned,
it increases in the blood, but in a very small proportion.
Examples:
Experiment DCXLIII. April. Dog weighing 15.8 kilos. Drew 33 cc.
of arterial blood from the carotid .... A
Placed a tube in the trachea, and immediately afterwards, a
stopper in the tube. Struggling, dead in 4 minutes.
A cannula was inserted into the left heart; at the moment when
the heart stopped, 33 cc. of very dark blood was drawn . . . . B
A contains per 100, CO, 33.9.
B contains per 100, CO, 40.8.
This answers most decisively the question which we asked our-
selves at the beginning of this chapter: Does the carbonic acid
produced during asphyxia play any part in causing death?
All that we had learned showed us already that its role in all
cases must be decidedly limited. In order that carbonic acid may
bring on death in dogs, its proportion in the air must be more
than 30%; now in the confined air in which the animal is asphyxi-
ated, it never rises above 17 to 18. On the other hand, the dis-
turbances of circulation, locomotion, calorification, etc., and the
variations of the oxygen of the air and the oxygen of the blood are
the same in the cases in which the carbonic acid was eliminated
from the confined air in which the animal is breathing (Chapter
III, Subchapter II) and in ordinary asphyxia.
But the experiments which we have just reported show that
the increase of carbonic acid in the arterial blood of asphyxiated
animals, when it exists, never reaches a figure much higher than
Gases of the Blood 935
that found sometimes in the blood of animals breathing free air;
the maximum was 53.6 (Exp. DCXLI), and the visible symptoms
of poisoning by carbonic acid do not appear before the blood con-
tains 70 to 80 volumes of this gas. Finally, the question cannot
even be asked in cases where carbonic acid, far from increasing,
diminished in the blood and the tissues.
This is the time to recall Experiments DCXXIV, DCXXV,
DCXXVI, reported in the matter of poisoning by carbonic acid, in
reference to the quantity of this gas dissolved in the tissues. They
show, in fact, that in the animals of Experiments DCXXXVIII,
DCXXXIX, and DCXL, the tissues contained only a small quantity
of carbonic acid, hardly, if any, greater than is found there nor-
mally. Finally, the urine of asphyxiated dogs released, in presence
of an acid, only 15 to 20 volumes of C02 (Exp. DCXXXIX, DCXL) ,
that is, the quantity found on the average in dogs given a mixed
diet.
All this collection of facts shows decisively, then, that carbonic
acid plays no part in the death of dogs, which are drowned,
strangled, or asphyxiated in a very small quantity of air, and that
this part is negligible when asphyxia takes place in larger spaces.
Perhaps it would be unwise to apply this last conclusion to ani-
mals in which, as in sparrows, the lethal tension of carbonic acid
in the air is only from 22% to 26%; here again, however, Experi-
ment DCXXVIII C shows that carbonic acid has no great im-
portance.
However, its decrease in the tissues when the asphyxia took
place in air freed of carbonic acid or in expanded air (Experiments
DCXXVIII D and DCXXIII) may perhaps explain the few differ-
ences we noted between asphyxia in closed vessels and asphyxia by
decompression, mentioning particularly rigor mortis.
Subchapter III
OBSERVATIONS ON THE GASES OF THE BLOOD
The numerous analyses of the gases of the blood which I have
reported in this book deserve to occupy us some moments, even
disregarding considerations relating to barometric pressure.
I shall say at the very beginning that the high temperature to
which I raise the blood in the gas pump permitted me to extract
the gases of the blood much more rapidly and much more com-
pletely than my predecessors could manage to do. Of course, at
936 Experiments
40°, under a vacuum, one finally obtains almost all the oxygen
and all the C02 contained in the blood; but it takes a long time,
the successive pump strokes bring only small quantities of gas,
there comes at the same time water vapor in which the carbonic
acid is dissolved again at the time of the condensation, and finally,
a more serious matter, a small quantity of oxygen may be consumed
during the operation. On the contrary, at the temperature of
boiling water, all the gases are immediately extracted by the
vacuum, and it has sometimes happened that I extracted all of
them with a single stroke of the pump.
Nitrogen. According to the researches of Fernet, 100 volumes
of blood, at 15°, can dissolve 1.4 volumes of nitrogen. I have often
found figures a little higher than this, which signifies nothing,
because some bubbles of air may have been left in the whole ap-
paratus; but I have also found some a little lower, and this is more
interesting. Setting aside possible causes of error, we find in this
the suggestion that the blood, as it passes through the lungs, is not
sufficiently agitated with the air to become saturated with the
gases which it is capable of dissolving.
This becomes a certainty when we consider the results of the
experiments on the gases of the blood of animals placed in com-
pressed air. In fact, nitrogen is very far from following Dalton's
law, because at 10 atmospheres, for example, I found as a maxi-
mum only 11.4 volumes (Exp. CLXXXIII).
I shall return in a moment to this important observation.
Oxygen. The proportions of oxygen which we have found in
the same volume of blood, in animals of the same species and in
equally good health, have varied within limits of astonishing
extent.
I am presenting here a table as much for carbonic acid as for
oxygen, using, of course, only experiments made on animals breath-
ing ordinary air at normal pressure. I placed in parentheses and.
I do not include in the average of the analyses those in which the
animals were sick or breathed under abnormal conditions: the
necessary specifications are given in the column of observations.
And so, eliminating extraordinary circumstances, the extremes
were for oxygen 24.0 (Exp. DCLXVI) and 14.4 (Exp. CCLXXX) .
There are 8 analyses giving from 14 to 15, 9 giving from 16 to 18,
29 giving from 18 to 20, 25 giving from 20 to 22, and 9 from 22 to 24;
the general average was 19.4. But we see that I was right to take
often in the course of this book as an average the proportion of 20
volumes per 100.
Gases of the Blood
937
Table XX
Experiments
0.
CO Observations
CLIV
(17.7)
— Exhausted by suppuration
CLV
19.7
45.0
CLVI
21.4
39.5 1
CLVI bis
21.2
40.1 [Same animal
CLVI ter
21.5
38.6 J
CLVII
19.7
36.7 Curare
CLVIII
(24.6)
(3 1.2) Medulla sectioned, at rest
CLVIII bis
(18.2)
(28.8) Medulla sectioned, struggling
CLIX
18.6
37.0 Quiet
CLIX bis
19.4
35.2 Struggling
CLX
(11.7)
(33.6) Animal in state of traumatism
CLX bis
(12.4)
(32.7)
CLXI
15.1
40.8 Normal respiration
CLXI bis
20.3
(24.0) Trachea; exaggerated respiration
CLXIII
18.8
39.7
CLXIV
21.5
41.9
CLXV
21.6
36.3
CLXVI
18.3
(32.8) After the decompression
CLXVII
19.8
(29.1) After the decompression
CLXVIII
(26.4)
(22.7) After the decompression
Very rapid respiration
CLXIX
20.6
39.0
CLXX
21.9
34.7 Before the decompression
CLXX bis
21.1
35.2 After the decompression
CLXXI
19.4
48.4 After the decompression
CLXXII
20.1
41.1 After the decompression
CLXXIII
22.6
39.7
CLXXIV
(13.3)
(34.9) Sick, same as CLXXI
CLXXV
17.4
33.8
CLXXVI
(16.9)
45.7 After the decompression
CLXXVII
(14.8)
(22.1) After the decompression
CLXXVIII
19.2
. —
CLXXIX
20.8
46.1 Before the decompression
CLXXIX bis
20.8
40.5 After the decompression
CLXXXI
19.2
35.0
CLXXXII
19.4
35.3
CLXXXIII
18.3
37.1
clxxxiv
18.4
47.7
CLXXXV
22.8
50.1
CLXXXVI
20.2
37.1
CLXXXVII
19.0
48.0
CLXXXVIII
18.2
50.8
CLXXXIX
21.5
47.3
cxc
21.6
45.0
CXCI
22.2
(29.4)
CXCII
18.0
49.0
CCLXXVIII
15.5
(22.9) Respiration by tracheal tube,
exaggerated
CCLXXIX
17.0
39.0
CCLXXX
14.4
41.0
CCLXXXI
16.9
33.0
CCLXXXII
18.1
(24.9) Respiration by tube,
exaggerated
CCLXXXIII
19.8
(20.9) Respiration by tube, exaggerated
CCLXXXIV
(12.1)
(29.6) Respiration by tube, exaggerated
CCLXXXV
15.1
40.8 Natural channels
CCLXXXVI
15.8
43.0 Tube in the trachea
CCLXXXVII
17.2
(22.3) Tube in the trachea
CCLXXXVIII
16.0
41.5 Natural channels
CCLXXXVin bis
(23.4)
(15.2) Trachea
938
Experiments
Table XX— Concluded
Experiments
CLXXXIX
CCXC
CCXCV
CCXCVI
CCCII
DCV
DCVI
DCVII
DCVIII
DCIX
DCXVI
DCXVII
DCX1X
DCXXXVIII
DCXXXIX
DCXXXIX bis
DCXL
DCXLI
DCXLII
DCXLIII
DCXLIV
DCXLV
DCXLVI
DCXLVII
DCXLVIII
DCXLIX
DCL
DCLI
DCLII
DCLIII
DCLIV
DCLV
DCLVI
DCLVII
DCLVIII
DCLIX
DCLXI
DCLXII
DCLXIII
DCLXIV
DCLXV
DCLXVI
Average
O- CO- Observations
16.0 44.5
18.7 44.0
17.0 38.5
19.0 42.0
( 7.3) (33.0) Little dog weighing 1640 gm.
(16.0) (29.5) Sick with traumatism
21.0 43.5
(24.8) (19.5) Breathing by natural channels
but with extraordinary rapidity
18.9 36.5
22.0 46.7
19.1 44.8
22.5 39.5
21.8 44.6
15.9 44.8
19.8 40.1 Natural channels
(21.5) (18.3)Trachea; exaggerated respiration
21.8 42.9
15.7 36.5
(14.6) 46.7 Young animal
19.0 33.9
( 9.4) (27,6) Little dog weighing 1850 gm.
15.5 37.2
22!5 38'.9 Fasting s flnirnal
20.2 36.5 Digesting bame animal
17.9 33.0
19 3 34 '3
(15.0) 34^9 Animal of DCXLIX, sick.
20.9 39.1
21.0 40.3
2i,2 -
(16.8) (35.3) Animal of Exp. CLXXII, sick
18.0 —
18.1 (25.0) Very rapid respiration through
tracheal tube
20.8 33.3
19.6 39.4
20.4 36.6
22.1 36.1
19.3 38.7
22.6 42.4
20.0 40.4
16.7 36.1
24.0 50.3
19.4 40.4
These variations may be due either to the presence of a les-
sened quantity of hemoglobin in the same volume of blood (even
if there should be the same number of corpuscles), or to a les-
sened saturation of this hemoglobin in the conditions in which the
animal is breathing, or finally to an inner difference in the nature
of the hemoglobin and its lessened capacity for absorbing oxygen.
But here, the thought suggested a moment ago by the study of
nitrogen appears with much more importance. Almo"st never, in
Gases of the Blood 939
the usual conditions of respiration, is the arterial blood saturated
with oxygen, nor does it contain all the oxygen that it can absorb
by agitation with air. Nothing is more variable than this differ-
ence between the amount of oxygen which the arterial blood does
contain and that which it can contain.
There are therefore individuals in whom a certain increase in
the rapidity and amplitude of the respiratory movements can in-
crease considerably the oxygen of the blood, and others, on the
contrary, who can get almost no advantage from it. These two
classes will, therefore, not be in identical conditions, from the point
of view, for example, of diminution of pressure. Inversely, there
are individuals who, being more saturated already, will be far
more able than others to bear a certain slowing down of respira-
tion, without having the proportion of the oxygen of their blood
fall to too low a figure.
In a general way, the oxygen content of the blood is shown by
the red coloration, and the redder a blood is, the more oxygen it
contains. But that is absolutely true only of the same blood. My
analyses have very often shown me, on the contrary, that certain
light red bloods were poor in oxygen, compared to other bloods
with a dark shade.
That is because the redness shows only the oxygen content of
the hemoglobin (oxy-hemoglobic combination). If we imagine two
bloods containing the same quantity of oxygen, the one which is
very rich in hemoglobin will be considerably less red than the other.
I have indeed after a copious bleeding found a blood redder than
or as red as before, although with a considerably lower oxygen
content; only the tint was lighter, because the blood was less laden
with corpuscles.
This occurs in young animals. Experiments CCCII and DCXLV
showed us in puppies a light red blood which contained only 9.4
and even 7.3 volumes of oxygen. This explains the low resistance
of young animals (I am not speaking of new-born animals, of
course) to asphyxia, chilling, etc. They are, in the highest degree,
anoxyhemic.
My analyses show also that in sick animals the quantity of
oxygen contained in the arterial blood is very small. Indeed, it
dropped, for example, to 13.3 in the dog of Experiment CLXXIV, an
animal which was suffering from a festering wound resulting from
bleedings, and which, when healthy, had given 19.4 (Exp. CLXXI) .
It seems to me extremely probable that in certain cases of sick-
ness, the lessened quantity of oxygen contained in the blood must
940 Experiments
result, not only from a lessened quantity of corpuscles or even of
hemoglobin, but from an alteration in the latter, which becomes
less fitted to absorb oxygen. This is a very important subject for
research, the study of which, at my suggestion, Dr. Legerot6 has
begun.
At any rate, setting aside very young animals and sick ones, it
is certain that great differences exist between different animals of
the same species in regard to the oxygen content of their blood.
On the other hand, in the same animal, considerable changes in
the circulatory and respiratory rhythms may greatly change this
oxygen content. I have already noted these facts in the chapter
which deals with the discussion of my method of analyzing the
gases of the blood. Experiments CLVI, CCLXXXVIII, and
DCXXXIX, listed in the preceding table, are quite characteristic
from this point of view.
Carbonic Acid. Carbonic acid has been extracted from the blood
in proportions even more variable than those of oxygen. The
extremes, eliminating exceptional data, have been 50.8 (Exp.
CLXXXVIII) and 33 (Exp. CCLXXXI). There were 36 analyses
giving from 30 to 40, 32 giving from 40 to 50, 3 above 50? and the
general average was 40.4.
The acceleration of the respiration, especially when it is carried
on directly by the trachea, lessens the quantity of C02 in the
blood in a proportion that is often enormous. I have already men-
tioned these facts in dealing with the experimental criticism and
the degree of accuracy which may be attributed to the analyses of
the gases of the blood. The data given by our experiments are
reproduced in the table above: these are Experiments CLXI bis,
CCLXXVIII, CCLXXXII, CCLXXXIII, CCLXXXVII bis, DCVII,
DCXXXIX bis, DCLVI. I call attention particularly to Experi-
ment CCLXXXVIII, in which the quantity of CO. fell from 41.5
to 15.2 by tracheal respiration; and Experiment DCVII, in which
an exaggerated respiration, through natural channels however,
brought this gas to 19.5.
So the diminution of the carbonic acid of the blood through
exaggerated respiration under normal pressure may reach almost
the same degree as in animals subjected to the lowest atmospheric
pressures, since Table X gives as averages 29.3 at the pressure of
34 cm., 23.2 at that of 25 cm., and even 12.4 at that of 17 cm.
If we refer to the circumstances of the extraction of the gases
by the pump, we shall see that the ease of this extraction depends,
as one might have expected, on the quantity of them which exists
Gases of the Blood 941
in the blood. In this reference I made a fairly large number of
experiments to see in what proportions oxygen and carbonic acid
escape from the blood, when the pressure is gradually lowered.
The experiment was set up in the following manner: after a
partial vacuum had been made in the barometric pump, I placed
in it the blood to be analyzed; then I extracted, by successive
strokes of the pump, a part at the same time of the air which
remained and the gases which had escaped from the blood; I con-
tinued thus until nothing more came out. The gases extracted by
each of the successive strokes of the pump were then subjected to
just as many analyses. Here are the results of one of these analyses
by stages:
Experiment DCLX. January 23. 100 cc. of blood taken from the
brachial artery of a large shepherd dog.
The gas pump was brought to 16.5 cm. of actual pressure; I
introduce the blood, agitate it for a moment, and with the first stroke
of the pump extract 92 cc. of gas .... A
At a second extraction, I secure 85 cc. of gases . . . . B
At the 3rd (pressure 12.5 cm.) 61 cc. of gases . . . . C
At the 4th (pressure 5 cm.) 25 cc. of gases . . . . D
At the 5th (up to a vacuum) 2.5 cc. of gases . . . . E
The hot bath was boiling; I then placed in the receiver a little
sulphuric acid diluted with boiled distilled water. 1 cc. more of C02
was extracted.
The analyses show that:
Gas A contained neither On nor C02, coming from the blood.
Gas B contained 02 1.9 cc. and CO, 1.9 cc.
GasC contained 02 13.9 cc. and C02 17.8 cc.
Gas D contained 02 4.6 cc. and C02 12.0 cc.
Gas E contained O, 0.4 cc. and C02 1.6 cc.
The total contained Oa 20.8 cc. and C02 33.3 cc.
CO.
The ratio between the carbonic acid and the oxygen was
02
then successively: in B, 1; in C, 1.3; in D, 2.6; in E, 4. The total ratio
being 6, it results that during the first phase of the experiment, there
escaped from the blood proportionately more oxygen than carbonic
acid; the contrary took place in the second phase.
Other similar experiments give the same evidence, and it would
be useless to give the details of them. Furthermore, when I placed
the blood in a perfect vacuum and analyzed separately the gases
obtained by successive strokes of the pump, I always got a similar
result. Experiments made on animals subjected to low pressures
did the same (See Table X, Col. 4, 5) .
And so, from whatever side we approach the problem, we see
942 Experiments
that under the influence of decreased pressure, the blood first ioses,
proportionately, its oxygen more quickly than its carbonic acid;
then equilibrium is established; then the carbonic acid escapes in
larger proportion; and finally, the pump brings only carbonic acid.
The same thing is true even when it is a question of blood in
which the proportion of carbonic acid is much higher than the
average. The experiments on carbonic acid poisoning give us
numerous examples.
In Experiment DCXIV, in Blood C which contained C02 103.6
co2
and O., 18.2, the ratio being 5.7, the first strokes of the pump
o2
co2
brought a gas in which the ratio was 5.2, whereas the last
strokes gave the ratio 6.0. Similarly, in Experiment DCXV, for
CO,
Blood E (CO, 97.5; 0„ 13.7), the ratio being 5.2, we had for
o2
the first tubeful of gas the ratio 4.7, and for the second, the ratio 9.
The vacuum of the gas pump, used as I specified, combined with
the temperature of boiling water, removes almost all the carbonic
acid contained in the blood. The later addition of a strong acid
sets free only minimal quantities, sometimes none at all: the ex-
periment which I have just reported gives a satisfactory example of
that.
We know how much the opinions of physiologists and chemists
have varied in regard to the carbonic acid which can be extracted
by the pump (acid which is "free", "dissolved", "ausgepumpen" of
the Germans) and that which resists a vacuum aided by heat (acid
which is "combined", "bound", "gebunden"). Earlier authors
thought the latter very abundant (Lothar Meyer estimated it at
28.58 as against 6.17 of the free acid) ; but the analyses of Schoffer,
Setschenow, Pfliiger, etc., have successively reduced the proportion
to what we have observed ourselves.
In blood artificially saturated with carbonic acid, this gas is in
three forms: simply dissolved, weakly combined (bicarbonates and
phosphocarbonates) , or strongly combined (carbonates). But in
what form does it exist in normal blood, both arterial and venous?
In these natural conditions is there simply dissolved carbonic
acid? M. Fernet (loc. cit., page 209), had concluded from his ex-
periments that in saturated liquid, that is, containing 156.1 cc. of
Gases of the Blood 943
CO, per 100 cc. of blood (beef blood at 16°), the largest part (96.4
cc.) of this acid is dissolved in the blood, since it follows Dalton's
Law in its relation to the barometric pressure, and since the rest
(59.7 cc.) is combined in the form of bicarbonate or phosphocar-
bonate, because it escapes this law.
Now our analyses have shown us that in arterial blood only
very rarely are there 50 volumes of C02. We may say then that
regularly the arterial blood contains only C02 in combination, both
weak and strong. On the contrary, in the blood of the right heart
we have found, on the average, higher proportions of C02; this
blood then seems to contain in addition C02 simply dissolved.
This leads us then to think that respiration, so far as carbonic
acid is concerned, consists chiefly and perhaps exclusively of an
exhalation of the excess of carbonic acid simply dissolved, the part
combined in the state of bicarbonate or phosphocarbonate being
only slightly or not at all modified. In perfect respiration, at its
regular rhythm, no dissolved acid should remain in the arterial
blood.
With the purpose of gaining light upon this point, which is im-
portant for the general theory of respiration, I began experiments
with the following method. I draw from an animal arterial blood,
the carbonic acid tension of which I determine immediately by
means of a vacuum and heat. Then for two hours, by means of the
water motor (See Fig. 42), I agitate another sample of the same
blood in a flask full of pure carbonic acid: a rubber bladder, also
full of C02 and communicating with the flask, prevents absorption
from lessening the gaseous tension. After this time, another an-
alysis. I then subtract from the number found the quantity of CO,
which the blood would be capable of dissolving at the actual tem-
perature (the observations of M. Fernet permitted me to use Bun-
sen's tables for the coefficients of solubility), and the remainder
should show whether there is still dissolved C02 in the arterial
blood. For greater clarity, let us take an example: let us suppose
that the arterial blood has given 40 volumes of C02, and that after
agitation at 16° it contains 138; the coefficient of solubility being
96.4, we see that the salts of the blood required for saturation
138 — 96.4 = 41.6; therefore, in the blood they were not at the maxi-
mum of carbonization, because for that they lacked 1.6 volumes
of C02.
Here are some experiments made by this simple method. The
first two include in addition the analysis of the gas of the blood
of the right heart:
944 Experiments
Experiment DCLXI. July 4. Dog.
Drew 25 cc. of blood from the femoral artery.
It contains O. 22.1; CO- 36.1. Simultaneously 25 cc. of blood from
the right heart. It contains 02 5.5; CO 56.4.
100 cc. of blood are shaken for 24 hours with pure CO; (tempera-
ture 20°).
They then contain 127.4 of CO;.
Coefficient of solubility at 20°: 91.5. Then, 127.4 — 91.5 = 35.9.
Therefore, the salts of the arterial blood are exactly saturated. As for
the venous blood, it contains 20.5 volumes of dissolved C02, saturation
being perfect.
Experiment DCLXII. July 9. Dog, digesting, weighing 8 kilos (it
dies during the night as a consequence of the hemorrhage).
Drew from the femoral artery 25 cc. of blood, which contains
O, 19.3 and CO,- 38.7 (at 0° and 760 mm.).
Drew at the same time from the right heart 50 cc. containing CO,
49.0. Then 350 cc. of arterial blood are taken and shaken all night
with pure C02.
The next day (temperature 20°), this blood contains 172.1 volumes
of CO=.
The coefficient of solubility of C02 at 20° was 91.5; 172.1 — 91.5 =
80.6. It results that the arterial blood lacked 41.9 of being chemically
saturated with CO., and that the venous blood itself lacked 31.6 cc.
Experiment DCLXIII. June 26. Large dog; I draw from the ca-
rotid 25 cc. of blood, which contains O. 22.6; CO. 42.4.
Agitation for 18 hours with pure C02. Contains then (tempera-
ture 23°) 146.8 volumes of CO?.
Coefficient of solubility at 23°, about 87; 146.8 — 87 = 59.8. There-
fore, for saturation, the bases of the arterial blood lack about 17.4
volumes.
Experiment DCLXIV. July 11. Dog, fasting, weighing 10 kilos.
Drew 25 cc. of blood from the femoral artery; it contains 0= 20.0;
CO. 40.4.
100 cc. of the same blood are shaken with twice its volume of pure
CO2. The next day (temperature 22°), analysis shows that the blood
contains 155.9 volumes.
Coefficient of solubility at 22° : 90.1. Therefore there are lacking
for saturation 25.4 volumes of CO=.
Experiment DCLXV. July 18. Dog, fasting, weighing 13 kilos.
Experiment similarly conducted; arterial blood 02 16.7; CO? 36.1.
After agitation (40 hours) in CO, contains 147.6 (temperature 20°).
Coefficient of solubility at 20° : 91.5. Therefore, lack for saturation
of 20 volumes of CO,.
Experiment DCLXVI. July 22. Dog, fasting, weighing 11 kilos.
Arterial blood: O, 24.0; CO. 50.3.
July 26. After agitation: CO. 167.0 (temperature 22°).
Coefficient of solubility at 22°, about 88.5. Therefore, lack for
saturation of about 28.2 volumes of CO..
Gases of the Blood 945
Experiment DCLXVII. August 20. Dog, fasting.
Arterial blood: CO. 54.0.
After agitation for 5 hours with pure carbonic acid, the blood con-
tains 166 volumes of CO, at 22°.
The coefficient of solubility being 90.1, we see that the bases lacked
22 volumes of CO, for saturation.
Experiment DCLXVIII. July 24. Old horse, exhausted, paralyzed
in the hind quarters; one of the sympathetic nerves in the neck has
just been cut.
Drew carotid blood on the side of the sympathetic that was cut.
It contains O. 11.8; CO, 44.8.
At the same time took venous blood from a branch of the jugular;
it contains O- 11.8; C02 54.0.
Before sectioning, the venous blood had given C02 50.1. Shaken
for 24 hours, with pure C02 contains (temperature 19°) 178.2 volumes
of CO;. It has taken on a very strange dark color, which I have never
seen.
Coefficient of solubility at 19° : 92.5. Therefore, there is lacking
for complete saturation of the bases of the arterial blood 40.9 volumes
of CO;, and for that of the venous blood before any nervous section,
31.7.
We see that in none of our- experiments did the arterial blood
contain carbonic acid that was simply dissolved; only once were
the alkaline bases exactly saturated (Exp. DCLXI) . Furthermore,
the venous blood itself, in Experiments DCLXII and DCLXVI, con-
tained only carbonic acid in combination; but in Experiment
DCLXI, there were 20.5 volumes of dissolved CO.,
Perhaps, before drawing definite conclusions, we should make a
larger number of experiments; however, for the arterial blood, the
agreement of our analyses is perfect, and I think we can consider
that it is proved that all the dissolved carbonic acid (when it exists
in the venous blood) escapes in passing through the lungs, and that
the supercarbonated alkaline salts are, moreover, dissociated there
from a part of their acid, hardly exceeding one third.
But this last limit may be exceeded, and a larger proportion of
combined carbonic acid may escape through respiration and no
longer be found in the arterial blood. This happens particularly
at the time of exaggerated respirations through a tube placed in
the trachea; it happens in curare poisoning, when artificial respira-
tion is given, even with precautions; it happens after or during the
convulsions due to compressed oxygen (see particularly from this
point of view Experiment CCLXXXVI, in which the proportion of
CO,, dropped to 9.9 volumes in the arterial blood) ; it happens,
finally, through respiration in rarefied air. The alkalinity, of the
946 . Experiments
blood must increase considerably in these circumstances, which
could not fail, if the circumstances continued for some time, to
exercise a considerable influence on the state of health of the ex-
perimental animal; we shall return to this last point when in the
third part of this work we study the conditions of life of dwellers
in high places.
1 Lecons sur la physiologic comparee de la respiration, page 521.
2 In these lines, as in those of Figure 75, the volume of the gas was not reduced to 0°.
3 Lecons sur la respiration, p. 431.
4 Bull, de la Sociite philomatique, 186), p. 13.
» See the recent work of J. Boehm, Ueber den Einfluss der Kohtensaiire auf das Ererunen
und IVachstum der Pftansen. (Zitzb. der k. Akad. der Wissensch., LXVIII Bd. Wien. 3873.
n-L* -.ege£Dt'. Etudes dh&motoltgie paVwlugique basics sur I' extraction deSga£ da saw*
Iheses de Paris, 1875. * ■
Part Three
RECENT DATA, SUMMARY AND
CONCLUSIONS
Chapter I
DECREASED PRESSURE
Subchapter I
OBSERVATIONS, THEORIES, AND RECENT
DISCUSSIONS
The principal results of the experiments reported in the second
part of this book, and the theory drawn from them in regard to the
influence of high elevations were submitted to the judgment of the
public several years ago.1 The idea that symptoms produced by a
sojourn in rarefied air, particularly mountain sickness, are caused
solely by the lessening of the oxygen tension in the air, and are in
fact only a form of asphyxia, has aroused much criticism, generally
not very instructive, which it would be tedious to reproduce here.
Among those who took it upon themselves to oppose my conclu-
sions, some seem not to have an exact knowledge of them, and
particularly not to have read the experiments on which they are
based. For instance, M. Bouchut 2 wrote the following lines in 1875:
One might question whether it is really the diminution of the
oxygen of the blood that causes mountain sickness, and not rather
a carbonhemia due to the accumulation of carbonic acid in the blood,
which dulls the organs and disturbs their functions; but that makes
no difference in the fact itself, which is incontestable. In my opinion,
and according to my experiments, the nervous phenomena of asphyxia
are all due to the dulling action of the carbonic acid retained in the
blood. In fact, I have demonstrated that all animals that die asphyx-
iated for want of oxygen have previously a more or less pronounced
anesthesia, and I am surprised that aeronauts have not announced
this fact, since it is so easy to verify it on a mammal placed beneath
the receiver of an air pump.
949
950 Summary and Conclusions
I have read many strange articles on this subject. I shall quote
only one, however, because it had the honor of insertion in the
Official Journal,3 and because it can serve as a model in this common
art of hiding ignorance behind pompous scientific terms:
To have a satisfactory explanation of mountain sickness, we must
use modern knowledge of human physiology and physics. The cause
of these phenomena was at first thought to be the increasing rarefac-
tion of the air as one ascends.
The diminution of density of atmospheric strata does indeed pro-
duce an acceleration of pulse and respiration; but these symptoms
remain isolated and are often unnoticed by aeronauts at heights much
greater than those at which mountain sickness appears. Increase in
frequency and depth of respirations compensates for the rarefaction
of the air. Furthermore, oxygen in this case, though it is less abun-
dant, appears to be better fixed and dissolved in the blood, a fact which
lessens by so much the inconveniences of its rareness.
However this may be, ascent into the upper regions of the air,
if it has a certain effect, possesses it only in a secondary way as if to
make more noticeable and more speedy the effect of the increased
labor which walking requires; for it is in the increase of mechanical
labor that we find the real reason for mountain sickness.
To maintain animal warmth and life, man in repose requires a
determined quantity of heat, furnished by hydrogen and carbon. Ac-
cording to modern theories, all mechanical labor is the result or the
transformation of an equivalent quantity of heat supplied by inner
combustion.
This heat, transformed into labor, does not raise the temperature
of the body; but it cannot be produced without giving the usual
residues, which are, we know, carbonic acid and water vapor. The
increase in labor caused by exhausting ascents consumes in the blood
the materials of heat production, and produces an excess of carbonic
acid, of which the system rids itself by speeding up respiration. Even
this outlet is often insufficient; and hence the phenomena which we
have described, and which are all the more marked because the trav-
eller is in a cold region; and hence too the speed with which they
disappear when the traveller rests, and requires from his breathing
only the heat necessary for his existence.
The excess of carbonic acid is removed and everything becomes
normal.
There are some who have protested in the name of the ancient
theories, and have revived the unfortunately classic ideas about the
decrease of the weight supported by the body, hemorrhages by
suction, and the peripheral cupping-glass. I reported earlier the
strange discussion begun in the Academy of Medicine, and the
opinion of M. Colin on the role played by expanded intestinal gases.
Dr. Chabert,4 in a recent thesis, after reporting and adopting
Decreased Pressure 951
our theory, cannot refrain — though not without remorse — from sac-
rificing also to the ancient gods, the false gods:
The acceleration of respiration and circulation really has as its
principal cause the more pressing need of oxygen .... But certain
secondary causes also favor this acceleration. Among others, we admit,
as a possible aid towards this result, the greater tension of liquids
and gases of the blood, an increase in tension which is generally con-
sidered to appear in lofty regions, and is due to the diminution of
surrounding pressure. It would give the blood greater fluidity, while
the diminution of atmospheric pressure would permit the capillaries
to dilate, they say, and consequently give the blood freer passage.
But has not the influence of the latter cause been somewhat exagger-
ated? Should not the intense cold of the regions where air is rarefied
amply counterbalance this effect, already doubtful, on the peripheral
circulation? The cold, in fact, produces a state of stasis of the blood
in the capillaries on which its influence can manifest itself, that is,
on those which lowering of pressure might influence. Now, this effect
of cold should lessen greatly the action (perhaps still problematical)
of atmospheric decompression in this case; and to support our opinion
we see in the observations that we have reported that this peripheral
circulation is far from being speeded up as much as is said. M. Glaisher
complains that his hands grew blue; in another ascent, he was forced
to pour brandy over the hands of his companion, Coxwell, which had
become black and numb, and we have seen the same thing take place
on other occasions. (P. 28.)
These old hypotheses ought not to stop us now; a word or two
will be enough presently to summarize definite disproof.
■ But we are far from treating with the same scorn the interesting
theory developed by M. Dufour. We have seen, in the historical
part of this book, that in 1874 this scientist, without yet knowing
of our experiments, had expressed the opinion that mountain sick-
ness is due to the exhaustion, through exaggerated muscular con-
tractions, of the ternary materials of the blood and the tissues,
materials necessary for the production of heat and work. The reply
to this theory appears of itself and we have expressed it in a few
words (page 340). The discussion which took place in the bosom
of the Medical Society of Switzerland having informed M. Dufour
of the results of my experiments, he somewhat modified his point
of view, and finally decided that one must distinguish between
"height sickness" and "fatigue sickness," the combination of these
two factors producing "mountain sickness." Here are his own
words:5
A. Height Sickness. The blood loses its oxygen supply according
to rules established by M. Bert for some animals. And so, if one can
• apply to man the results obtained in animals, at 4200 meters the blood
952 Summary and Conclusions
would already have lost a fifth of the oxygen which it ought to con-
tain, at 6400 meters almost a half, and so on.
It is clear that this constitutes a pathological state, which comes
from the simple fact that one breathes at too low a pressure, or in an
air containing too little oxygen. Height sickness is the only harm ex-
perienced by aeronauts, if we do not take into account the influence
of the cold.
B. Fatigue sickness. This is the consequence of muscular labor.
If labor is repeated or violent, as after the rapid ascent of a long
flight of stairs, fatigue sickness will be an asphyxia for lack of oxygen
and excess of carbonic acid in the blood. If the muscular labor is long
and not compensated by food, the organism will suffer from inanition.
Asphyxia by muscular labor will hardly be produced on the plains,
if the labor is not too rapid; it will be easily produced on the heights,
according to the findings of M. Bert. But prolonged labor, whatever it
be, will always finally produce pathological symptoms. These must be
very hard to determine exactly; it is probable, however, that it is to
fatigue sickness that most of the pathological symptoms observed in
the mountains are due.
Mountain sickness then would be a combined effect of height
sickness and fatigue sickness, or rather a fatigue sickness appearing
more quickly on account of the altitude. The more mountain sickness
appears at a low level, the more it depends on the factor of inanition
on which I have laid stress; the more it appears at a high level, the
more important the role which M. Bert's anoxyhemia plays.
Mountain sickness appears to us therefore as a complex phenom-
enon depending on altitude, fatigue (the latter in its turn depending
on labor and food) and the mental impressions which MM. Javelle and
Forel (Bulletin, March and June) have proved by interesting exam-
ples. (P. 263.)
The conclusion of this is:
That it is impossible for M. Bert to study mountain sickness under
the pneumatic bell. Why? Because he experiences only the influence
of rarefaction, that is, height sickness pure and simple. (P. 264.)
We make no change in our reply. Does the fatigue to which
mountain climbers are subjected have as its imminent cause the
exhaustion of carbon compounds of the muscles and blood, as M.
Dufour says? That hypothesis is probable, though not proved and
certainly incomplete. Much has been written and many experi-
ments have been made on muscular and nervous fatigue, and the
question is still full of obscurities. But after all, it does not matter
much whether this fatigue following excessive walking and con-
tinuous efforts of climbing is the result of excursions on hills 500
or 600 meters high, or in mountains over 4000 meters high. Now
the manifestations will be quite different in the two cases; and the
very name mountain sickness is highly characteristic. It appears
Decreased Pressure 953
only at a certain level, and that where the oxygen lack of the blood
has reached a sufficient degree, and we shall make this expression
exact in a moment. If aeronauts are not attacked until long after
mountain climbers, it is not because their reserve of ternary mate-
rials is intact, for they have only to make some efforts and they too
become sick, it is because their muscles in repose do not demand
of the impoverished arterial blood a quantity of oxygen which it
would be unable to furnish them. Does that mean that the dif-
ferent causes of fatigue play no part in the conditions of the ap-
pearance of mountain sickness? I have already replied to that
question; but it is doubtful that it is a matter of the using up of
the ternary materials, since a sleepless night, an indigestion, some
indisposition or other have the same unpleasant consequences. A
tired man presents the best conditions for the development of
mountain sickness; but it does not recognize fatigue as its cause,
since if fatigue operates alone, mountain sickness never appears.
M. Forel, whose works were discussed in our first part, wholly
adopted my ideas in his third Memoire.6 I reproduce here the
interesting account of an excursion made by this physicist into a
grotto in which the air was very poor in oxygen, an account which
we must compare with that of M. F. Leblanc and also, because of a
remarkable coincidence of symptoms, with my experiment CCLIV.
On June 23, 1864, I made an exploratory tour of the Grotte-des-
Fees of St-Maurice, a very profound cavern, which, among other
peculiarities, has an atmosphere very poor in oxygen; here is the result
of one of the analyses which Professor Bischoff made on air collected
1000 meters from the entrance of the cavern.
Nitrogen 82.66
Oxygen 15.33 7
Carbonic acid 1.99
If I calculate the oxygen tension in this air, I see that it is 14.7%,
the normal tension on the seashore being 20.9. This number corre-
sponds to the air tension at an altitude of more than 2000 meters.
After a stay of several hours in this cavern, studying my physio-
logical state, I observed: acceleration of pulse, acceleration of respira-
tory rate, and mental disturbances which I described then in the
following terms: When I wanted to count my pulse, I was obliged
to try seven times; I was often mistaken, I skipped numbers, I counted
twice in succession the same group of ten, or I counted a group of ten
beginning at the end.
The almost complete similarity of symptoms of mental disturb-
ances observed by M. Bert and myself, at such a great interval and
under such different outer conditions, seemed to me worthy of being
noted. (P. 88.)
954 Summary and Conclusions
M. Forel sees, as we do, the cause of the weakness of muscular
contractions during mountain sickness, in the exhaustion of the
oxygen of the muscle, and not in the consumption of the carbon
compound reserves of the organism, and he expresses himself excel-
lently on this subject:
We can reproduce the special fatigue of mountain sickness on the
plain by running rapidly up a very steep slope, a hundred stair steps;
for example, l'Escalier-du-Marche, at Lausanne, often served me for
this experiment. Getting near the top, one stops out of breath, inca-
pable of taking a step, a prey to violent palpitations, asphyxiated,
worn out, but especially incapable of taking a step, or raising the leg.
One is suffering from mountain sickness in all its perfection. Now in
this case, the work performed is not very considerable; it is far from
exhausting the reserve of combustible materials of the organism. But
this work is done very rapidly; this expenditure of strength is com-
pleted in a few minutes; it exhausts the reserve of oxygen, and even
though the air is not rarefied as it is on a high mountain, we are
asphyxiated. (P. 92.)
The memoir from which we have borrowed this contains the
very interesting accounts of ascents made by M. Forel at the
Gorner-Graat (July 4, 1873; 3136 meters), and at the Sattel Tolle,
on Monte Rosa (July 7, 1873; 4300 meters). It is a strange thing,
but one which will not surprise our readers too much, that our
traveller suffered very definitely from mountain sickness in the
first ascent, and was only slightly indisposed during the second, in
which, however, he mounted much higher.
Here, in fact, is what he says of his journey to the Gorner-Graat:
5:45. In my bed at Zermatt, temperature 36.75°.
11:45. Arrival at the hotel of the Riffel: 38.62°.
1:45. After lunch, 37.70°.
Excursion to the Gorner-Graat. Very slow walk to the col of the
Riffel (2780 meters). I am much affected by mountain sickness. Diffi-
culty in breathing. Flatulence. Nausea. Headache. Sleepy. Very weak
pulse. Respiratory rate 24, very deep. Pulse 93.
I make a sphygmographic record. (Fig. 82.)
Heart impulse very weak, very slow, dicrotism. Wretched pulse.
Siesta for a half -hour.
On the way to the Gorner-Graat, pulse 144. I drink some drops
of cherry water and the uneasiness disappears.
4:20. Arrived at summit of the Gorner-Graat (3136 meters).
38.36°.
Pulse 126, respiratory rate 30. (P. 109.)
On the contrary, the ascent of the Sattel Tolle was hardly pain-
ful at all:
Decreased Pressure 955
1:20. 2509 meters. Awoke at the hotel of the Riff el; temperature
37.10°.
4:30. 2850 meters. Temperature 38.14°; pulse 80; respiratory rate
34.
6:00. 3300 meters. Above this point, I begin to suffer from respir-
atory inconvenience and headache, my head seems encircled in a ring.
Our ascent is very slow partly because of this oppression, partly
Fig. 82— Pulse at the Riff el Pass (2780 m.), during mountain sickness
(ascent of July 4).
Fig. 83— Pulse at the Sattel-Tolle (4300 m.): on arrival (a); after a half-
hour of relative rest (b) (ascent of July 7).
because of the horrid state of the snow into which we sink at every
step up to the knees.
6:35. Respiratory distress increases; temperature 38.44°; pulse
100; respiratory rate 32.
7:45. 3700 meters. During the climb; temperature 38.25°; pulse
102; respiratory rate 42.
8.07: 3800 meters. Nausea; third lunch; pulse 80; respiratory rate
24; dyspnea.
956
Summary and Conclusions
We begin the ascent of the Botzer Tolle, which we make at one
stretch, except for a halt of a few minutes half way up. As we climb
I see disappearing one after the other most of the symptoms of moun-
tain sickness from which I had been suffering.
9:50. 4300 meters. At the Sattel Tolle, halt; temperature 38.59°;
pulse 80; respiratory rate 38.
10:00. The same; pulse 70.
10:35. Pulse, 104 to 120; fourth lunch.
10:50. Great irregularity of pulse which is at 86; that of my
guides is 102 and 108, irregular.
Descent.
3:00. Arrived at the Riff el.
4:00. Temperature 37.87°; pulse 93; respiratory rate 28.
3:45 in the morning at Zermatt (1620 meters) in my bed; tem-
perature 37.32°. (P. 102.)
Fig. 84 — Pulse at the Riffel (2569 m.), rest on the return trip (ascent of
July 7).
Fig. 85 — Pulse at Morges (380 m.), absolute repose (July 10)
I add here, for the sake of comparison, a sphymographic record
taken by M. Forel on his return to Morges (380 meters) July 10.
M. Forel attributes the differences between the sufferings of the
two ascents to becoming accustomed to the mountains, to the train-
ing due to the three days stay at the Riffel (2500 meters) :
Each year (he says) I suffered more in my first ascent of the
summer than in following expeditions. So, in 1865, I was very much
affected by mountain sickness on the col of the Geant at 3400 meters.
It was my first ascent; but six days after, trained as I was by succes-
sive passages of the cols of the Geant, of Joux, of Ranzola, of Ollen
and of Turlo, I made the passage of Weissthor, 3610 meters, without
suffering at all from the altitude. (P. 108.)
We ourselves made similar reflections (see page 324). The
disappearance of symptoms during the ascent of the Botzer Tolle
is a very interesting fact; M. Forel explains it in a very original
manner:
Decreased Pressure 957
In preparing for my expedition, I had taken care to get informa-
tion from everyone familiar with Monte Rosa as to the point where
the greatest suffering from mountain sickness is experienced. It is
well known that each mountain has its special locality in reference to
this; it is not generally on the summit, which is very airy and windy,
or on the dangerous or interesting ridges that the sickness is most felt;
it is particularly on snowy slopes, hollowed out, well protected
against the winds, and tiresome; as example I shall mention the
corridor of Mont Blanc. All the reports made to me were unanimous;
it was on the Botzer Tolle, before reaching the Sattel, that all the trav-
ellers, and even the guides often, were affected. On the ridge of the
summit, on the contrary, no one has the slightest idea of suffering
from mountain sickness. I prepared therefore to study carefully this
Botzer Tolle. I had its beginning indicated by the guides, and forced
myself from that point to climb rapidly and without stopping, so as
to heighten by fatigue the symptoms from which I was suffering be-
fore approaching it. But — strange thing — I saw these symptoms dis-
appear one after the other; as soon as I directed my attention espe-
cially to one of them, I felt it lessening. Fatigue, lassitude, depression,
headache, left me one after the other, and I made this tiresome
passage in perfectly good condition, to the amazement of my guides,
who had seen me painfully affected in regions much less dangerous
to other travellers. Attention, scientific interest then had for me in
this case the same curative effect that danger possesses; no one suffers
from mountain sickness in dangerous passages.
This effect on mountain sickness of the morale and of particular
attention ought to be pointed out, and deserves to have much more
consideration than it has received until now in the study of this
malady. I merely indicate it here. (P. 110.)
The temperature of the body, we see by the figures given above,
was maintained at its original degree, or even rose above it, during
muscular efforts; at any rate, no decrease has been observed. But
we must mention the fact that, precisely during the attack of moun-
tain sickness, that is, at the interesting moment, the temperature
was not taken. M. Forel, who mentions this omission himself, gives
"this negligence as a proof of the physical and mental distress
which he was feeling then." (Page 109.)
Two English travellers, having read the work of Dr. Forel, pub-
lished the notes which they had previously taken on the variations
of their buccal temperature during mountain ascents.
M. Thorpe * reached negative results. His ascent consisted of
climbing from Catana to Zaffarana: the buccal temperature showed
itself invariably 98.4 F.; the pulse rose from 78 to 83.
M. Tempest Anderson,9 on the contrary, said that he had ob-
served a considerable drop in the buccal temperature during the
very act of ascent; he asserts that he guarded against all causes of
958 Summary and Conclusions
error and had previously trained himself in thermometric readings;
the thermometer remained five minutes under the tongue. Here is
the summary of his observations, made in the hills of Yorkshire:
Table of M. Tempest Anderson.
Time Height Temp. F.
(Eng. feet)
In bed 7:30 900 97.7°
Before starting, being cold 9:40 900 97.6°
After a mile walk on the plain, and a rapid
ascent of 1000 feet, tired, hot, sweating, and
before stopping 11:20 1900 96.4°
Seated, after 10 minutes, neither hot
nor cold 11:30 1900 98.2°
Rapid ascent to the summit, which I reach
sweating, unable to breathe 12:00 2414 97.0°
Seated, having eaten a little, and finding
the wind cold 12:37 2414 99.3°
Rapid descent of 1000 feet, hot, without
stopping 1:10 1400 98.0°
Crossed the valley to climb Grageth; after
an ascent of 500 feet, hot, sweating, and
without stopping 2:17 1900 96.4°
Seated 2:24 1900 97.6°
Seated, cold 2:33 1900 98.6°
At the top of Grageth, walking slowly __ 2:52 2250 98.2°
Seated, cold *. 3:12 2250 98.4°
After descending rapidly 1000 feet 3:55 1200 98.0°
Seated 4:05 1200 98.0°
At the inn of the "George and Dragon" __ 9:50 500 97.9°
So the minimum temperature of 96.4 was observed during the
ascent, sweating freely, with a sensation of heat.
I agree with Dr. Marcet, that it is the fact of the ascent and not
the altitude in itself that influences the temperature.
A single theory can, according to M. Anderson, include appar-
ently contradictory cases, like those of M. Marcet and M. Forel.
The human machine, he says, has not the same output in all men.
The quantity of heat necessary for the work of the ascent can in
certain individuals be developed through greater activity in com-
bustion; it may be that others are incapable of this increase of
oxidation:
In the first class one would place M. Forel; in the other, that of
persons with weak powers of combustion, I place myself in the hon-
orable company of Doctors Marcet and Lortet.
Decreased Pressure 959
Table XXI
Elevat:
on
rs
Time
Temp.
of air
Calberla Age 26 Peter Bohren
Age
54 Peter
Muller.
32
mete
lemp.
Fuise
lemp.
Pulse
R.
Temp.
Pulse
R.
1638
12:30
37.0°
80
76
16
80
18
2799
3:15
+ 2.0°
104
36.8°
100
28
37.4°
108
28
3081
4:50
— 1.4°
37.4°
100
96
30
108
28
3302
5:55
—1.6°
112
37.0°
104
30
37.2°
104
30
3521
6:50
+ 1.8°
37.2°
108
108
30
112
32
3780
8:00
+ 2.0°
108
36.8°
112
26
37.0°
112
30
3817
8:50
+ 4.5°
37.4°
112
108
26
112
28
4008
9:37
+ 4.8°
124
36.8°
116
32
37.5°
120
30
4358
10:45
+ 3.6°
37.5°
132
116
30
120
28
4271
11:0(
(halt)
+ 4.1°
92
36.4°
88
20
37.0°
100
22
4462
11:50
+ 0.2°
37.2°
112
112
28
116
30
4553
12:06
— 0.4°
136
36.8°
120
30
37.2°
124
34
4695
(Summit)
12:55
+ 3.8°
37.4°
124
37.2°
120
28
37.2°
124
34
4663
(after
rest) 2
+ 4.8°
36. S°
88
36.8°
80
18
36.8°
96
20
4374
3:55
+ 4.6°
124
37.0°
96
24
37.2°
116
28
3012
5:20
+ 5.2°
37.4°
140
128
32
128
36
1644
9:30
36.8°
92
36.9°
88
18
37.2°
92
18
A German traveller, Calberla, published observations of the
same sort 10 taken on Monte Rosa. The table above (Table XXI)
summarizes the observations made on himself and two guides; the
temperatures were taken in the rectum, even while walking.
The variations in respiratory and pulse rate agree with all that
was already known. As for the temperatures, we see that they
varied, for Calberla and P. Muller, from 36.8° to 37.5°; for P. Bohren,
from 36.4° to 37.2°. During the ascent, the temperature kept rising;
the minimum observed was during a halt, at 4371 meters, or after
the rest on the summit of Monte Rosa, the temperature of the air
being + 4.8°.
Professor L. Thomas, in a note joined to the Memoire of Calberla,
says that he had measured his temperature under the tongue for
several years at Roccia Melone (3550 meters), at Levanna (3750
meters) , at the Grand Pelvoux (3954 meters) , without ever having
observed a lowering of temperature from the ascent.
But we must note that all these observations leave out entirely
the question of what would happen if the observers had really
suffered from the altitude; one point then still remains obscure, to
which I call the attention of scientific travellers: does the tempera-
ture decrease from the act of ascent during a really pronounced
attack of mountain sickness? But I must insist again on the pre-
cautions to be taken in the use of the buccal thermometer: at least
two minutes of application under the tongue are necessary, accord-
ing to the observations of M. Thorpe. And even so, the causes of
error are such that it is best to take the temperature in the rectum,
using maximum thermometers.
I shall quote also, as a document interesting for our subject,
some extracts from a letter which I received from Dr. Ward, who
960 Summary and Conclusions
was attached as physician to the railroad construction over the
Andes, from Callao to Oroya:
Almost all the men who worked on the tunnel, except natives
born on the mountain, suffered more or less severely from the de-
crease of pressure; however almost all became accustomed to this
influence quite rapidly, that is, after one or two weeks. Animals suf-
fered as did the men.
The natives are short, stocky men, with an immense lung capacity,
as is proved by the following measurements, taken on the bare skin,
on the level of the nipples.
Age Height Circumference of the chest
14 years 1 4 feet, 10 inches 36 inches
24 years 5 feet, 6V2 inches 35 inches
21 years 5 feet, 4 inches 35 inches
16 years 5 feet, 34V2 inches
30 years 5 feet, AV2 inches 30V2 inches
These men eat dry wheat, coca, coarse sugar, potatoes, with little
or more often no meat. With a handful of grain and coca, they can
work a whole day without giving any sign of fatigue.
M. Malinowski, engineer at Lima, sending me the letter from
Dr. Ward, adds:
A North-American, assistant engineer, having made a visit to the
tunnel one day, was attacked there by the sorroche very violently.
He was hurried to a place about 1000 meters lower in elevation, but
he soon died.
Dr. Vacher X1 has published an interesting study on the medical
stations of Davos (1650 meters) , in the Grisons, and of Mont Dore
(1050 meters) in Auvergne. He observes, as many of his prede-
cessors have done, the immunity to consumption of the population
of these elevated regions, and studies the question of the treatment
of this dreadful disease by the height cure. For our present topic,
we shall quote only the following observations:
1. At Davos, the heart rate is noticeably higher than on the plain;
at Paris, my pulse rate is 69; at Davos, 78. It is to this phenomenon
that the unsuitable name of "altitude fever" is given .... It continues
during the whole stay in this station, which distinguishes it from the
phenomena of excitation produced by mineral waters.
2. The functions of the lung are equally modified in this rarefied
medium, where a considerable amelioration of respiratory movements
is observed. Dr. Spengler asserts that in the atmosphere of Davos the
lung makes up for the deficiency of oxygen by deeper and slower
inspirations than in normal conditions of pressure. It is quite true
that at the altitude of 1650 meters there is a considerable lack of
oxygen in the air, but observation proves that it is not by deeper or
Decreased Pressure 961
more prolonged inspirations that the lung makes up for this deficit, but
by more frequent respiratory movements. At Davos, where I observed
myself carefully for several days, I noted 18.2 respiratory movements
per minute, while at Paris I have only 16.6. (P. 12.)
As first sign of improvement in the thoracic symptoms of con-
sumption, we observe at Davos an increase of respiratory capacity,
measured by aid of the spirometer, an instrument used at present in
this station (P. 13.)
On March 22, 1874, Croce-Spinelli and Sivel made their first
flight at great height, in which, encouraged by the result of trials
made in our cylinders, they took along bags of oxygen, so as to
overcome the effects of the decompression by breathing this gas.
The Polar Star, in which they made the ascension, a balloon of
2800 cubic meters, took them in two hours to a height of 7300
meters. I quote here the part of their account 1J which applies to
our subject:
We felt in our flight impressions similar to those which we had
experienced in the decompression bells of M. Bert, in which several
days before the ascension we were taken down to a pressure of 304
millimeters. However, in the basket, in which we reached 300 milli-
meters, the discomfort was much keener than in the bell, which should
be attributed to the harder work done, to the great drop in temper-
ature, and to the duration of our stay in the upper strata. While in
the basket we underwent cold of — 22 to — 24 degrees, we had a con-
stant temperature of +13 during the decompression on earth; further-
more, the sojourn in the bell lasted only an hour, which is almost the
duration of that part of lofty ascensions which is above 7000 meters,
whereas we remained in the air 2 hours and 40 minutes, and one hour
and 45 minutes above 5000 meters. Moreover, in the bell, the pure
oxygen which we were breathing caused dizzy spells like those of
drunkenness, whereas on the contrary we were very comfortable with
the two mixtures, one of 40% oxygen and 60% nitrogen, and the other
of 70% oxygen and 30% nitrogen, which M. Bert had furnished us
for our ascent.
We began to breathe the 40% mixture at 3600 meters, and con-
tinued to 6000 meters; we resorted to that of 70% for the great
heights, because the less rich was insufficient, particularly for M.
Croce-Spinelli. In the most rarefied regions, we both had to leave in
our mouths the rubber tubes connected with the gas bags. We
breathed thus from time to time, taking care to grip between our
teeth the elastic tube when we felt better. When M. Sivel threw out
ballast, which prevented him from breathing gas, the 15 kilogram
bags seemed to him to weigh 100.
For M. Croce-Spinelli, of lymphatico-nervous temperament, the
effects were quite different than for M. Sivel, a very vigorous man, of
sanguine temperament. When the former was no longer breathing
oxygen, he was obliged to sit down on a bag of ballast and make his
observations, motionless in that position. During the absorption of
962 Summary and Conclusions
oxygen, he felt revived, and after about ten inhalations, he could rise,
chat gaily, look at the ground attentively, and make delicate observa-
tions. His mind was keen and his memory excellent. To look into
the spectroscope he had to breathe this gas, rightly called vital; the
lines, at first confused, then became very clear.
The oxygen also produced in M. Croce-Spinelli an effect whose ex-
planation is easy, after what has just been said. To react against the
combined effects of cold and rarefaction, he tried to eat. The result
was not favorable at first; but when he had the idea of breathing
oxygen at the same time, he felt his appetite return and his digestion
working smoothly. As for his pulse, it was 140 beats before absorp-
tion and 120 immediately - after, between the elevations of .6560 and
7400 meters. His pulse on the ground is 80, on the average.
Neither of us had the bleeding from the nose, lips, and ears of
which Gay-Lussac 13 had complained, although our faces were very
red and the mucous membrane almost black. At times, as in the bell,
we felt heat in our faces and pricklings in our heads. At times, our
foreheads seemed clamped in a vice, and there was a sensation of a
solid bar of small size pressing hard above the eyebrow. An inha-
lation of oxygen dispelled most of these painful sensations.
The descent was made almost without ballast and without oxygen;
the provision, of which M. Croce-Spinelli had absorbed almost two
thirds, was exhausted. About 4000 meters, when the temperature had
risen to — 7°, M. Sivel was seized with a very strong tremor and
extreme discomfort. His face was contracted, and his mouth was
opened in a kind of rictus. His companion, though less vigorous, at
the time felt only a very keen cold produced by the rapid passage
through the air. While at — 22°, we both felt only a rather slight
sensation of cold, because the air was calm; we were shivering in the
rapid descent. Besides there was certainly another cause of the dis-
comfort of M. Sivel; perhaps he had worked too hard. This discomfort
disappeared at 2500 meters.
We had companions in the basket; we took along carrier pigeons,
which had been lent us by M. Van Roosbecke. Four pigeons, chosen
among the best carriers, were in a cage, with the feather prepared
which was to receive the dispatch. They seemed very uncomfortable
at lofty elevations; they leaned on their bellies and had their eyelids
closed.
The first pigeon was thrown out at 5000 meters, half an hour
after the start. At first it flapped its wings, and tried for some time to
get up on its cage, then, seeing that its efforts were in vain, it de-
scended with its wings spread out, describing circles of 200 to 300
meters in diameter, with a terrifying speed of about 40 to 50 meters
per second. That is the only one that returned with its dispatch, and
it took more than 30 hours to get to its destination. The second,
thrown out after the start, at about 5200 meters, behaved in the same
way. However, it had the strength to fly up on its cage.
We call special attention to the favorable effects of inhalations
of oxygen. Return of strength and appetite, decrease of headache,
restoration of clear vision, calmness, presence of mind, all the phe-
Decreased Pressure 963
nomena already observed in the cylinders of my laboratory were
reproduced with a certainty that, under the dramatic circumstances,
was very striking and inspired in the two aeronauts a reckless con-
fidence, which proved fatal to them.
April 15, 1875, they began another ascent to great heights, taking
with them M. Gaston Tissandier. To the ring of the balloon were
fastened three gas bags filled with a mixture of 72% of oxygen.
These gas bags, I can say today, were quite insufficient in capacity.
I was then absent from Paris, and warned by a letter from Croce-
Spinelli of their coming expedition, a letter in which he specified
the quantity of oxygen which they were going to take with them
(it was to be, I think, 150 liters) , I warned him of its insufficiency.
"In the lofty elevations where this artificial respiration will be
indispensable to you," I said to him, "for three men you should
count on a consumption of at least 20 liters per minute; see how
soon your supply will be exhausted!" My letter arrived too late, it
seems; the day of the ascension was set, and they drew from my
observations only this conclusion which was so fatal, that they
should wait for absolute necessity to make use of the gas bags. We
know what happened; when the aeronauts, feeling asphyxia over-
come them, tried to seize the life-giving tubes, their arms were
paralyzed.
M. Gaston Tissandier, the only survivor of the Zenith catas-
trophe, wrote 14 a powerful account of it from which I shall borrow
freely:
Thursday, April 15, 1875, at 11:35 in the morning, the balloon
Zenith rose from the ground at the gas works of La Villette. Croce-
Spinelli, Sivel, and I had taken our places in the basket. Three gas
bags filled with a mixture of air with 70% of oxygen were fastened to
the ring. At the lower end of each of them, a rubber tube passed
through a wash-bottle filled with an aromatic liquid. This appara-
tus, in the upper regions of the atmosphere, was to furnish to the
travellers the oxygen necessary to maintain life. An aspirator bottle
filled with petrol, which the low temperature cannot solidify, was
hung outside the basket; it was to be suspended vertically at a height
of 3000 meters to force air into the potash tubes intended for the
determinations of the carbonic acid ....
We start, we rise in the midst of a flood of light, emblem of joy,
of hope!
Three hours after the departure, Sivel and Croce-Spinelli were
inanimate in the basket! At 8000 meters altitude, asphyxia had struck
with death these disciples of science and truth!
It is for their travelling companion, who miraculously escaped
death, to close his heart to grief for a moment, to drive away sad
memories and gloomy visions, so that he can report the data gathered
964 Summary and Conclusions
during the expedition, and tell what he knows of the death of his
unfortunate and glorious friends ....
At 4300 meters, we begin to breathe oxygen, not because we feel
as yet the need of resorting to the gaseous mixture, but merely be-
cause we wish to convince ourselves that our apparatuses, so well
arranged by M. Limousin, according to the proportions specified by M.
Bert, are functioning properly.
I should say that my dear and regretted Croce-Spinelli had in-
sisted energetically that I should take part in the high elevation
ascension that he was at first to make with Sivel alone. M. Herve-
Mangon, president of the Society of Aerial Navigation, and M. Hureau
de Villeneuve, secretary general, did not approve this project, simply
because they feared, I hasten to add, that Sivel would be deprived of
the necessary amount of ballast, since my presence would cause its
amount to be lessened. However these gentlemen yielded to the in-
sistence of Croce-Spinelli. Who could have resisted the charm of his
captivating speech and his gaze? "My friend Tissandier", said Croce
to me a few days before the first ascension of the Zenith, "don't worry,
you shall go with us. I won't leave you behind", he added, embrac-
ing me. "It takes three to make a high elevation ascension to verify
the results. And who knows? Something might happen. Six arms
are better than four! Besides, you must breathe oxygen in the upper
strata to bear witness with us that it is both effective and necessary."
Croce-Spinelli had an ardent love for the truth, and was so frank
and loyal that he could not permit anyone to doubt his statements.
At the height of 7000 meters, at 1:20, I breathed the mixture of air
and oxygen, and felt my whole being, already oppressed, revive un-
der the action of this cordial; at 7000 meters, I wrote in my notebook
the following lines: I breathe oxygen. Excellent effect.
At this height, Sivel, who had unusual strength and a sanguine
temperament, began to close his eyes at times, to grow drowsy, and
to become a little pale. But this valiant soul did not long abandon
itself to weakness: he drew himself up with an expression of firm-
ness; he had me empty the liquid contained in my aspirator after
my experiment, and he threw out ballast to reach loftier heights.
The year before, Sivel had reached 7300 meters with Croce-Spinelli.
This year he wanted to mount to 8000 meters, and when Sivel used his
will-power, it took very great obstacles to hinder his designs.
Croce-Spinelli had for some time been consulting the spectro-
scope. He seemed to be beaming with joy, and had already cried:
"There is complete absence of the lines of water vapor." Then, after
having uttered these words, he continued his observations with such
ardor that he begged me to write in my notebook the result of his
thermometer and barometer readings.
During this rapid ascent, in the midst of numerous occupations,
it was difficult for us to give to physiological observations the at-
tention they required. We were saving our strength in this regard for
the time when we should have entered the upper regions, without
suspecting the fatal outcome which was to paralyze our efforts. It
was possible for us, however, to obtain the following results, which
we take from the notebooks:
Decreased Pressure 965
Time Altitude
12:48 4602 meters . . . Tissandier, pulse 110
12:55 5210 meters . . . Croce, buccal temperature 37.50°.
1:03 5300 meters . . . Croce, pulse 120.
1:05 5300 meters . . . Tissandier, number of inspirations
determined by Croce, 26.
1:05 5300 meters . . . Sivel, pulse 155.
1:05 5300 meters . . . Sivel, buccal temperature 37.90°.
Here is the average of the observations which had been taken
previously on the ground for several days in succession:
Pulse Respiratory Rate Buccal Temperature
Croce-Spinelli 74 to 85 24 37.3°
Sivel 76 to 86 unknown 37.5°
Tissandier 70 to 80 19 to 23 37.4°
I come to the fatal hour when we were about to be seized by the
terrible influence of the atmospheric decompression. At 7000 meters
we are all standing in the basket; Sivel, numbed for a moment, has
revived; Croce-Spinelli is motionless in front of me. "Look", he says
to me, "how beautiful these cirrus clouds are!" The sublime spectacle
before our eyes was indeed beautiful. Cirrus clouds, in different
forms, some long, others rounded, formed a circle of silvery white
around us. And leaning out of the basket one could see, as if at the
bottom of a well, whose walls were formed by the cirrus clouds and
the vapor below, the surface of the earth which appeared in the
abysses of the atmosphere. The sky, far from being dark or black,
was a clear and limpid blue; the glowing sun burned our faces. How-
ever the cold had already begun to be felt, and we had already
wrapped ourselves up. Numbness had seized me; my hands were cold,
icy. I wanted to put on my fur gloves; but without my realizing it, the
action of taking them from my pocket demanded an effort which I
could no longer make.
At this height of 7000 meters, however, I was writing in my note-
book almost mechanically; I copy verbatim the following lines, which
were written without my having a clear memory of them at present;
they are nearly illegible, written by a hand which the cold caused to
tremble strangely:
"My hands are icy. I am well. We are well. Vapor on the horizon
with little rounded cirrus clouds. We are rising. Croce is panting.
We breathe oxygen. Sivel closes his eyes. Croce also closes his eyes.
I empty the aspirator. Temp. —10°. 1:20. H = 320 mm. Sivel is
drowsy . . . 1:25. Temp. — 11°, H = 300 mm. Sivel throws out ballast.
Sivel throws out ballast." The last words are hardly legible.
Sivel, in fact, who had remained for some instants thoughtful
and motionless, sometimes closing his eyes, had no doubt just remem-
bered that he wanted to pass above the limits where the Zenith was
then soaring. He drew himself up, his energetic face lighted up sud-
denly with unusual animation; he turned towards me and said to me:
"What is the pressure?" — "30 centimeters (about 7450 meters alti-
tude)". "We have plenty of ballast, shall I throw some out?" — I
answered, "Do as you please". — He turns to Croce and asks him the
966
Summary and Conclusions
same question. Croce nods his head with a very energetic sign of
affirmation.
There were in the basket at least five bags of ballast; there were
about as many more hung outside on cords. The latter, I should add,
were not entirely filled; Sivel had certainly ascertained their weight,
but it is impossible for us to make an estimate of it.
Sivel seized his knife and cut three cords successively; the three
bags emptied and we rose rapidly. The last very clear memory which
remains to me of the ascent goes back to a moment a little before this.
Croce-Spinelli was seated, holding in his hand the wash-bottle of the
oxygen; his head was slightly bent and he seemed oppressed. I still
had the strength to strike with my finger the aneroid barometer to
help the movement of its needle; Sivel had just raised his hand to-
Fig. 86 — The basket of the Zenith at a high altitude.
Sivel G. Tissandier Croce-Spinelli
cuts the cords which hold observes the after making the spectro-
to the basket the ballast barometers. scopic observations, is
bags full of sand. about to breathe oxygen.
Decreased Pressure 967
wards heaven as if to point out the upper regions of the atmosphere.
Fig 86 reproduces as exactly as possible the appearance of the basket
of the Zenith at this solemn moment.
But soon I was keeping absolutely motionless, without suspecting
that perhaps I had already lost use of my movements. Towards 7500
meters, the numbness one experiences is extraordinary. The body and
the mind weaken little by little, gradually, unconsciously, without
one's knowledge. One does not suffer at all; on the contrary. Gne
experiences inner joy, as if it were an effect of the inundating flood
of light. One becomes indifferent; one no longer thinks of the perilous
situation or of the danger; one rises and is happy to rise. Vertigo of
lofty regions is not a vain word. But as far as I can judge by my
personal impressions, this vertigo appears at the last moment; it im-
mediately precedes annihilation, sudden, unexpected, irresistible.
When Sivel had cut the three bags of ballast, at the altitude of
7450 meters, that is, at the pressure of 300 mm. (that is the last figure
I wrote in my notebook), I think I remember that he sat down on
the bottom of the basket, and took almost the same position as Croce-
Spinelli. As for me, I was leaning in the angle of the basket, where
I succeeded in standing only by the help of this support. I soon felt
so weak that I could not even turn my head to look at my companions.
Soon I wanted to seize the oxygen tube, but could not raise my
arm. My mind, however, was still very lucid. I was still looking
at the barometer; my eyes were fixed on the needle which soon reached
the pressure number of 290, then 280, beyond which it passed.
I wanted to cry out, "We are at 8000 meters!" But my tongue
was paralyzed. Suddenly I closed my eyes and fell inert, entirely
losing consciousness. It was about 1:30.
At 2:08, I awoke for a moment. The balloon was descending
rapidly. I succeeded in cutting a bag of ballast to check the speed,
and in writing in my notebook the following lines, which I copy:
"We are descending; temperature — 8°; I am throwing out ballast,
H = 315 mm. We are descending. Sivel and Croce still unconscious
at the bottom of the basket. Descending very rapidly."
Hardly had I written these lines when a sort of trembling seized
me and I fell inanimate again. The wind was blowing violently
upward, and indicated a very rapid descent. Some moments after, I
felt myself shaken by the arm, and recognized Croce, who had re-
vived. "Throw out some ballast", he said to me, "we are descending."
But I could hardly open my eyes, and did not see whether Sivel had
awakened.
I remember that Croce had unfastened the aspirator which he
threw overboard ,and that he threw out ballast, wraps, etc. All that
is an extremely confused memory which soon ended, for I fell back
into my inertia still more completely than before, and it seems to me
that I went into an eternal sleep.
What happened? It is certain that the balloon freed of ballast,
impermeable as it was and very warm, mounted once more into the
upper strata.
At about 3:30, I opened my eyes again, I felt numb, weak, but
my mind was active. The balloon was descending with terrifying
968 Summary and Conclusions
speed; the basket was swinging violently and describing great oscilla-
tions. I dragged myself on my knees and pulled both Sivel and Croce
by the arm. "Sivel! Croce!", I cried, "wake up!"
My two companions were crouched in the basket, their heads
hidden under their travelling rugs. I assembled my strength and tried
to raise them. Sivel's face was black, his eyes dull, his mouth open
and full of blood. Croce's eyes were half shut and his mouth bloody.
To tell in detail what happened then is impossible. I felt a ter-
rible wind rushing upward. We were still at an altitude of 6000
meters. There were in the basket two bags of ballast which I threw
out. Soon the earth drew near, I wanted my knife to cut the rope
of the anchor: impossible to find it. I was frantic, I kept crying:
"Sivel! Siveir"
Luckily, I succeeded in finding my knife and unfastening the
anchor at the right moment. The shock as we struck the ground was
extremely violent. The balloon seemed to be flattened and I thought
that it was going to remain where it was, but the wind was strong
and carried it away. The anchor did* not hold and the basket slid flat
over the fields; the bodies of my unhappy friends were jostled this
way and that, and at every moment I thought that they would fall
out. However I got hold of the valve cord, and the balloon soon
emptied, then ripped against a tree. It was four o'clock.
As I set foot on the ground, I was seized by a feverish excitement,
and fainted, growing livid. I thought I was going to join my friends
in the other world.
However I recovered little by little. I went to my unhappy com-
panions, who were already cold and rigid. I had their bodies shel-
tered in a neighboring barn. Sobs choked me!
The descent of the Zenith took place in the plains near Ciron
(Indre), 250 kilometers from Paris in a direct line. . . .
After having reviewed the story of the ascension of the Zenith,
I come to two important points which have keenly occupied the at-
tention of scientists and the public.
What is the maximum altitude reached by the Zenith?
What is the cause of the death of Croce-Spinelli and Sivel?
The first question is settled today by the opening of the baro-
metric tubes (as evidence) contrived by M. Janssen, and used before
by Sivel and Croce-Spinelli in their ascent to 7300 meters (March
22, 1874).
One tube had broken, others had met with accidents or worked
badly, but there were two which had functioned properly, and which
furnished us with results that checked. They tend to show that the
lowest pressure was 264 to 262 millimeters, which sets the maximum
height at 8540 to 8601 meters (correction made for pressure at the
ground level).
As at the moment of my unconsciousness, at 8000 meters, the
needle of the barometer was passing rapidly over the pressure num-
ber of 28 (8002 meters) and indicating thus an ascent of great speed, I
am convinced that we reached this altitude of 8600 meters in the
first ascent. After the first descent, Croce-Spinelli and very certainly
Sivel were still alive; they were struck by death when the balloon
Decreased Pressure 969
reached for a second time the high levels which it had just left, but
which it was not to pass beyond, its weight and volume certainly not
permitting it to mount higher.
I do not think it doubtful that the death of these unfortunate
men is the consequence of the atmospheric decompression; it is pos-
sible to endure for a very short time the action of this decompression;
it is difficult to undergo its effect time after time during nearly two
almost consecutive hours. Our sojourn in the upper strata was, in
fact, much longer than that of any preceding ascension to the higher
elevations. I will add that the air, which was particularly dry, pos-
sibly had a dangerous effect.
It will be asked now what was the cause of my own safety. I
probably owe my life to my peculiar temperament, essentially lym-
phatic, perhaps to my complete unconsciousness, a sort of pause of
the respiratory functions. I was fasting at the moment of our start,
and I thought at first that this circumstance was peculiar to me, but
I have since had proof that if Sivel had eaten, Croce, like me, had
almost no food in his stomach.
The decompression is considerable at the height of 8600 meters,
since the mercury column of the barometer is at only about 26 cm.
I am convinced that Croce-Spinelli and Sivel would still be living,
in spite of their prolonged sojourn in the higher strata, if they had
been able to breathe oxygen. Like me, they must have suddenly lost
power of movement. The tubes conducting the vital air must have
slipped from their paralyzed hands! But these noble victims have
opened new horizons to scientific investigation; these soldiers of
science in death have pointed out the dangers of the way, so that
their successors may know how to foresee and avoid them.
M. G. Tissandier has tried to represent by the accompanying
diagram (Fig.#87) the course of the balloon, which, as we see, de-
scribed in space a sort of gigantic M, 8600 meters high. The dotted
part of the curve represents the second phase of the ascension;
probably it is very like the real graph. It is during this part of the
voyage that Croce-Spinelli and Sivel lost their lives, in the midst of
these icy deserts of the high atmospheric levels!
I think it worth while to reproduce here some extracts from an
account drawn up by M. Limousin, a distinguished pharmacist,15
who had been commissioned to furnish the oxygen necessary for
filling the gas bags:
In order to prevent the probable rupture of the goldbeater's
skin as a result of the expansion of the gas at a high altitude, only
100 liters of the mixture (oxygen 65; air, 35) were put in each gas
bag, whose capacity was about 200 liters.
To neutralize as much as possible the detestable smell which the
greased goldbeater's skin gave the gaseous mixture, I put in for each
balloonist very small wash bottles provided with a curved tube fur-
nished with rubber so that they could be held in the mouth like a
970
Summary and Conclusions
pipe, leaving the hands free to put down observations in a notebook.
With this arrangement, the gas, passing through water flavored with
benzoin, reached the lungs fresh and perfumed.
Unfortunately, all these precautions were, if not useless, at least
of very little use. Because of the speed of their upward flight and
Fig. 87— Diagram of the high altitude ascent of April 15, 1875.
the sudden collapse of the aeronauts, the inhalations could not be
made at the moment when they were most indispensable.
M. Gaston Tissandier, who at first had experienced its good ef-
fects, could not ,at one moment, find enough energy to raise his hand
to reach the inhalation tube. On his return, he assured me that at
the time of descent of the balloon, which took place, as we know, at
Ciron, near Le Blanc, in Indre, the gas bags were fastened below the
Decreased Pressure 971
basket, still containing the larger part of the oxygen that had been
put into them.
And so we see that the only means that could have averted the
terrible catastrophe which ended this ascension could not be used ....
Commissioned by the Society of Aerial Navigation to aid the artist
who was to make the busts of the two unhappy aeronauts, we had
the coffins opened, on their arrival at the Gare d'Orleans, on Sunday,
April 18, at 11:45 in the evening, and I was struck by the state of
preservation of the features and the faces.
I could almost have done without the disinfectants with which
I was furnished to facilitate the measuring of the faces
Sivel had preserved his virile and energetic face; he showed no
sign of hemorrhage in mouth or nose; his face, slightly swollen, was
not cyanosed.
Croce-Spinelli had his nostrils and mouth filled with blood which
we had to remove by repeated washing. On his forehead, his nose,
and his right cheek were blackish patches produced by the ecchymoses
resulting from bruises caused by the oscillations of the basket. Never-
theless, in spite of the blood which covered them, the lips did not
have the bluish tint characteristic of asphyxia, and the left side of
his face had almost preserved its normal color.
The catastrophe of the Zenith profoundly moved our country;
everyone remembers the solemn funeral rites of the victims, the
tributes of political and scientific bodies, the open subscription for
the benefit of the families of Croce and Sivel, a subscription which
produced nearly 100,000 francs. May 23, in a great meeting, where
for the last time the eloquent voice of Pastor Athanase Coquerel,
Jr., was heard, I could say 16 in all truth:
A month and a half has passed since the catastrophe of the
Zenith, and in our country, unjustly accused of frivolity and forget-
fulness, the emotion which it aroused is not yet calmed.
This is a remarkable fact upon which we should dwell. Every
day the newspapers bring us accounts of terrible disasters, floods,
explosions, fires, shipwrecks, which cost the lives of scores, of hun-
dreds of men; it seems that our emotions should be stirred by these
and that the loss of two men should hardly affect them. Nay, more!
Our country, our heroic and unhappy country, has hardly completed
a period of sorrows and sacrifices, in which it mourned not only those
who died in her defense, but also those who, still alive, are now torn
from her; and yet we learn the death of two men, of only two men,
and all France trembles and mourns.
That is because everything in this double death is strange and
sublime. Certainly Sivel and Croce-Spinelli are not the first aeronauts
whose loss science has had to deplore; their names are the last of a
list at the head of which shine the names of two other scientists,
Pilatre du Rozier and Romain, who were dashed to pieces on the
beach of Boulogne in 1785. But the death which had struck these two
aeronauts was a well-known death, foreseen, common in a way; a
972 Summary and Conclusions
death of which everyone had thought, that everyone had feared from
the day when the contrivance of Montgolfier appeared in the air;
that was death by falling. Thus they died. But here, for the first
time, we saw two men die in the very bosom of the air, and die while
ascending. They felt death coming, a death unknown till then; their
oppressed breasts warned them of danger; they took counsel: "Must
we descend?" Ah! The consultation was not long. "We have ballast,
we can make still more useful observations up there; excelsior,
higher! And then they say that an Englishman could live and make
observations above 8000 meters: the flag we carry must float higher
yet!" They leap up, and death seizes them, without a struggle, with-
out suffering, as a prey fallen to it in these icy regions where an
Fig. 88— Sivel.
eternal silence reigns. Yes, our unhappy friends have had this strange
privilege, this fatal honor, of being the first to die in what we call
the heavens.
And by a painful jest of fate, they died at the moment when
science was furnishing them the means to triumph over the danger
to which they fell victims.
It was a scientific purpose of great theoretical importance," of
immense practical consequences, that our two friends were pursuing.
To determine the direction, the strength, the thickness of the aerial
Decreased Pressure 973
strata in movement; to measure the variations of temperature, elec-
tricity, humidity, the chemical composition of the air, at different
heights; to analyze the constituent elements of the stars, by rising
above the sort of screen which the lower strata of the atmosphere
form: such were the principal problems which they had set them-
selves. The utility of ascensions to great heights has been denied:
that is denying evidence. Everything leads us to believe that the
balloon, by its power of ascension, can carry the observer beyond the
extreme limits where the highest clouds float. Now what source of
prosperity for humanity could be compared to the unfailing predic-
tion of weather? How can we hope to reach that goal without know-
ing thoroughly this region where rain, snow, and hail are formed,
Fig. 89— Croce-Spinelli.
and where the winds and storms are engendered? And how can we
know this region without ascension to a great height, which permits
us to reach its domain and, if I may speak thus, to dissect the atmos-
phere?
I owed these explanations to the Society of Aerial Navigation;
I owed them to the memory of our unhappy friends. Furthermore,
no one was deceived. Everyone understood that these were men of
science, who died doing useful scientific research, and that is the sec-
ond reason which explains the emotion aroused by their death.
There is a third, more thrilling, more poignant perhaps. Let us
go back in thought five years, to the terrible winter. Paris is enclosed
in a circle of iron; all communications are cut off; on land, unsur-
mountable obstacles; nets bar the river. But the air is left, this new
route opened by a Frenchman, Montgolfier, on which a Frenchman
was the first to venture, Pilatre du Rozier; brave men — M. G. Tis-
sandier was among them — rose into the air, braving a thousand
974 . Summary and Conclusions
dangers, without speaking of the enemy's bullets, spreading in the
provinces the news which mitigated the anguish of separation, bear-
ing with them the energetic emotion, the unconquerable resolution
of the great city to do its duty to the end. So, I dare say, and who
will contradict me — when the news spread that two men had died
in a balloon, Paris recalled these hours of pain and hope, France
trembled, and all hearts throbbed as they used to throb when someone
told us that a balloon had landed, that someone had seen a balloon
in the air.
And so this double death, which seemed as if it were impressed
with a strange and mournful poetry, as if lighted up by the halo of
science, awoke again memories of the purest patriotism. Is not that
enough to explain why it has aroused in all France a feeling so keen,
so universal, so lasting?
0
The emotion of men of science was especially manifested on the
one hand by notes and memoirs attempting to explain the death of
the two aeronauts, on the other by inventions intended to prevent
henceforth such terrible catastrophes. I am forced to state that
nothing said or imagined on this subject deserves to be reproduced
here. From the theoretical point of view, they are only new edi-
tions of old ideas, already condemned, whose strange series we
have already listed in our history; for this particular case there has
been added the toxic effect of illuminating gas escaping in floods
from the balloon, which had been too rapidly dilated, and poison-
ing the aeronauts. The protecting inventions are worth just as
much as the theories which inspired their authors. Most of them
speak of divers' suits, glass cages, closed baskets, with confined or
compressed air, artificial atmospheres, sources of oxygen, etc.; but
nothing which was proposed so seriously is as good as the charm-
ing mystification of the "Journey to the Moon" and M. Jules Verne
will excuse me for not discussing it here.
Dr. Stoliczka, a geologist well known for important works on
the mountains of India, had in 1864 crossed many passes above 5000
meters in the Himalayas; he had had there "a horrible experience" 18
of fatigues and mountain sickness, and had regained health very
slowly. In June, 1874, he left with an English mission commanded
by Lieutenant Colonel Gordon, and died suddenly June 19, at the
age of 34, three days after having crossed Karakorum. The details
of his death given by the letters of Lieut. Col. Gordon and Capt.
Trutter 19 seem to indicate that the fatal effect of rarefied air played
an important part in the death oil the unfortunate geologist.
I give here the letter of Capt Trutter, the most interesting and
the most complete:
Decreased Pressure 975
June 16, the day when we crossed the Karakorum pass, he com-
plained of a pain in the back of his head; but since he always suf-
fered more or less from headaches as long as he was on lofty eleva-
tions, I thought that his pain meant nothing more; the pain con-
tinued the 17th, the day when we were crossing the deserts of Dip-
sang, where the level is still very high. Yesterday, the 18th, he
started early to investigate some rocks at Bruchse, and halfway along
he met us for lunch. He seemed very tired and complained about
his head. When we reached here about noon, he threw himself on
a bed, and soon began to breathe with difficulty and to cough a great
deal, and he vomited. His head and hands were very hot and his
pulse was quick and hard. He complained a great deal of pains in his
neck and the back of his head. By my advice, he put a mustard
plaster on his neck and another on his chest without feeling any great
relief. In the evening the cough became very severe, and the local
doctor prepared a mixture to soothe the irritation which caused the
cough; it continued just the same all night. In the morning it disap-
peared, but the patient, who was very weak, hardly seemed conscious.
Since the evening before he had said nothing, and replied only by a
few syllables to the questions asked him, without seeming to under-
stand very well what was said to him. This morning I asked him
twice if he felt any pain, to which he answered no.
The local doctor seemed to think that he had an attack of acute
bronchitis and pneumonia. But after what Capt. Biddulph and I had
seen of the sickness that attacked him last October, at Kizil-Jilga,
on the Kashgar road, the symptoms of which we recognized, it was
clear to us that the disease was the same as the first time, that is,
a spinal meningitis. By the doctor's advice, a plaster was placed on
his right side. He remained till noon in a state of half-consciousness,
and several times took chicken broth and brandy with his medicine.
He appeared neither better nor worse; his respiratory rate was
usually 50 to the minute, irregular, and often alternately deep and
difficult, or short and easy. The respiration was accompanied by
sonorous noises, which resembled the noise at the seaside or the
crackling of distant firing. Later, in the morning, it seemed to me
that the noise had become harsher. However, the breathing became
a little easier, and about 1:30 he signed that he wanted to be placed
in his chair. He was carried there and I gave him a little port, but
he seemed so weak and exhausted that I called Biddulph who, find-
ing the patient very low, went to get the colonel. When he was
placed in his bed, he tried at once to sit up; I held him from behind
to support him till the colonel should arrive; the noise of the death
rattle ceased — but he was still breathing deeply, his respiratory move-
ments became slower and slower, as did his pulse; finally he breathed
his last, dying so peacefully that it was impossible to fix exactly the
moment when he passed away. He had no agony, died apparently
without pain, and after his death an expression of rest and peace was
on his face.
From the moment when he came here until he died, he hardly
said a word, and all conversation became impossible; however, when
!)76 Summary and Conclusions
he looked at me, I thought I could see that he was conscious of his
critical condition.
He had told me a few weeks before that a second attack of
meningitis would bring certain death, since it is rare that one sur-
vives the first attack I cannot help believing that the elevation
had a good deal to do with the aggravation of the symptoms; he had
been exposed to the same cold in the Pamir expedition, and yet, the
elevation being less, he had experienced no harm.
I think that Capt. Trutter is right. I do not think that Dr.
Stoliczka succumbed to the influence of the rarefied air alone;
under the influence of an intense cold, he was probably attacked
by spinal meningitis complicated with broncho-pneumonia; but the
immediate prostration and death in two days should be attributed
to a complication unknown at ordinary levels. I certainly believe
that a lessening in the extent or the soundness of the alveolar
membrane, which at sea level would have brought only a slight
ailment, must have brought death by asphyxia in regions where
oxygen absorption was already reduced to a minimum. We shall
return to these data in the following subchapter.
An anatomist of high rank, who has just published a con-
siderable work on the respiratory apparatus of birds, tried, among
very interesting observations on the operation of this apparatus, to
explain the singular immunity which birds of lofty flight enjoy with
reference to the effects of rarefied air. In the opinion of M. Cam-
pana,20 it is all explained by the super-activity given to the re-
spiratory phenomena by the muscular acts of flight; so, he says,
alluding to the experiments in which I saw hawks hardly less
susceptible to decompression than the other birds:
I should unhesitatingly admit that these same condors, or better
yet, condors taken from a menagerie, might very well be subject to
all these functional disturbances, if, instead of rising freely in flight,
they shared in a passive manner in the ascent of a balloon, kept cap-
tive and motionless in a cage, in the bottom of the basket. For all
the greater reason, if one subjected them to decompression in closed
vessels. (P. 336.)
This survival without distress at heights which, for condors,
reaches 7000 meters, results from two causes, according to M.
Campana: let us examine them with the care that his important
work deserves. These two causes are expressed in the following
formula:
In mammals, mountain sickness, balloon sickness, is explained by
the impossibility of a thoracic expansion regularly continued and
sufficient, due to the weakness of the muscles which move the thorax;
Decreased Pressure 977
and also by the immediate exposure of a pulmonary parenchyma
retractile at a considerably weakened outer atmospheric pressure, and
by the annulment of the compensating function of the glottis. (P. 341.)
First, according to M. Campana, the movements of the wings
would put in play part of the aerial sacs (brachial prolongations
of the anterior-superior receptacle) situated between the motor
muscles of the wing sacs which remain motionless except in flight;
they would dilate at the elevation of the wing (that is, according to
the observations of M. Marey, at the moment of the tracheal in-
spiration), and would empty themselves of air at its lowering.
The result would be a considerably more rapid circulation of air
through the lungs, a more perfect ventilation, which would have
as a consequence that:
In the same conditions where mountain sickness appears in mam-
mals, birds in flight escape the two causes of anoxyhemia which at-
tack mammals, if not absolutely and indefinitely, at least to a much
greater degree. (P. 341.)
I consider the observations of M. Campana about the develop-
ment of air cells in the wings during the act of flight as perfectly
correct. But I think he has greatly exaggerated the importance
of this observation; first, the increase in volume acquired in this
way is not very great, considering that of the other gaseous reser-
voirs which act at the same time, that is, the extra-thoracic sacs.
In the second place, if I saw these aids of the respiratory act de-
veloping only during flight at great heights, I should admit that
they might then offer a certain utility: but they act equally at all
heights, provided that the bird is flying; and even if I believe that
they help thus to produce the increase of strength necessary for
work in the air and to establish the equilibrium of the organism
in a dynamic state, I do not understand how they can add, when
the low pressure becomes dangerous, a supplement of ventilation
and consequently of oxygenation which had not been already fur-
nished in the lower levels. Finally, even admitting that ventila-
tion is made perfect, we have seen that that is of little importance,
because it is the capacity of the blood for oxygen which constitutes
the real danger, since it has diminished with the height. The per-
fection of the ventilation can play only a very small role, since
it can only raise the quantity of oxygen contained in the arterial
blood in circulation to the amount which this blood would be
capable of absorbing if it was suitably saturated. This increase
is not to be scorned in mammals, and we shall dwell upon this
point in the following subchapter. But we ought hardly speak
978 Summary and Conclusions
of it in birds, because, according to the recent research of M.
Jolyet,21 their arterial blood is always nearly saturated with oxy-
gen; that, let us say in passing, is a fact of the greatest interest,
since it shows that in birds, contrary to the situation in mammals,
the conditions for the mixture of blood and air are perfect in the
respiratory apparatus.
The second reason indicated by M. Campana to explain the
resistance of birds of lofty flight is:
That they possess the means of removing the pulmonary paren-
chyma and up to a certain point the middle receptacles themselves
from the absolute dependence upon the barometric pressure which
the lungs of mammals endure necessarily during the inspiration.
(P. 342.)
In other words, during the inspiration as during the expiration,
the lungs, in consequence of the energetic injection carried on
alternately by the extra- and intra-thoracic receptacles, "are
crammed with air under a pressure greater than that of the outer
air." (P. 343.)
And so, the respiratory apparatus is removed up to a certain point
from the barometric pressure, which makes possible the ascent into
the higher levels of the atmosphere, and a fortiori the soaring flight
in the bosom of an icy and asphyxiating air.
I do not wish to report or discuss the details of the very com-
plicated mechanism by which M. Campana explains this com-
pression of the air in the interior of the lungs; in short, it amounts
to an injection of air too great for the section of the delivery open-
ings in the meshes of the pulmonary parenchyma. But I cannot
admit that such great importance should be attributed to this
slight excess of pressure, or that we should consider it as offsetting
the enormous decompression to which the bird will be exposed;
these intra-pulmonary modifications can be reckoned in millimeters
of mercury, whereas the outer decompression is measured by tens
of centimeters.
To my notion the question rests, and the immunity of condors
and vultures remains unexplained to me. Even if a study of the
effect of decompression in closed vessels should show us one of
these birds resisting much more than did our hawk, we should
be embarrassed by a sort of contradiction, but we should still have
no explanation. I shall return to these data in the next sub-
chapter when I speak of dwellers in high places, who seem to pre-
sent a similar immunity, like the yaks of the Himalaya and the
llamas of the Andes.
Decreased Pressure 979
I shall end this review of works published since the publica-
tion of the principal results obtained in my research by a short
analysis of the new book of M. Jourdanet.-2 This important work,
whose appearance I announced and some passages of which I
quoted in the first part of my present work, is divided into five
parts. In the first (vol. I, p. 3-84), entitled "Preliminary Baro-
metric Studies", I shall only mention here, without being able to
dwell on it, the curious chapter on the modifications of barometric
pressure in the geological ages, and their influence on living beings.
The second (p. 85-367) , "Climates of Altitudes", contains, besides
a masterly description of lofty, inhabited regions of the globe and
important statistics about Mexico, a summary of my own experi-
ments, and the study of the influence exerted by decompression
on travellers (mountain sickness) and on the inhabitants of lofty
regions. In the third part (vol. II, p. 3-154) "Pathological Consti-
tution of Altitudes", M. Jourdanet develops and supports by very
interesting medical observations his remarkable discovery of the
depressing influence of great heights, of the anemic state (anoxy-
hemic) of the dwellers in high places when they are attacked by
some disease. The fourth part (p. 155-204) deals with "Mountain
Climates". M. Jourdanet explains in the following terms the mean-
ing he attributes to this word, opposed to that of the climate of
altitudes:
I call altitude climates those which a sufficient elevation, com-
bined with the distance to the Equator, characterizes by the certain
signs of a respiratory alteration, as a consequence of the diminution
of the density of the surrounding air.
Below this physiological limit, since the barometric decompres-
sion does not act in a way harmful in itself, and may on the contrary
produce effects beneficial to health, I apply the term mountain cli-
mates to the conditions prevailing at moderate heights and on the
lower elevations of the soil in mountainous countries. (Preface, p. 2.)
In this fourth part are found data and particularly statistics of
such a sort as to cause sceptical reflexions on the vivifying air and
the fortifying effect of the mountains. Finally, in the fifth part
(p. 205-292), under the title of "Natural and Artificial Barometric
Transitions", the brief sojourn in mountainous places is very
cleverly contrasted with the effect of a prolonged abode; very in-
teresting observations are made there, besides, on the therapeutic
use of rarefied air.
We see that only the second part of this important work deals
with ground on which we ourselves are quartered. In this book,
980 Summary and Conclusions
when I analyzed the previous works of M. Jourdanet, I have given
his remarkable observations the place which they deserve; I cannot,
without repeating myself, return to them here. As to the hygienic
and medical considerations which my learned colleague has treated
with such length and interest, I can only refer the reader to this
book, which contains so many curious observations and new ideas,
so many proofs of profound and persistent learning, if I may use
the word "persistent", and guided by a theoretical idea which is
fortunate and fertile. He will wonder at the extent of the general
conclusions relative to the constitution of human races, to the
history of civilizations, and to philosophical politics, which M.
Jourdanet drew from this first observation, that, during a surgical
operation in Mexico, the blood which escaped from the arteries did
not present its usual reddish hue (vol. I, p. 171). But I cannot
continue longer here.
Subchapter II
SUMMARY AND PRACTICAL APPLICATIONS
We have given, in our second part, with a superabundance which
may perhaps have appeared excessive, the proofs of this truth that
diminution in the barometric pressure acts on living beings only
by diminishing the tension of the oxygen which they breathe, and
if things are carried to the extreme, by asphyxiating them for lack
of oxygen. Also that there exists a parallelism to the smallest
details between two animals, one of which is subjected in normal
air to a progressive diminution of pressure to the point of death,
while the other breathes, also to the point of death, under normal
pressure, an air that grows weaker and weaker in oxygen. Botli
will die after having presented the same symptoms; and at different
moments of the experiment, at death even, one can observe in
both the same proportion between the oxygen tension in the outer
air and its proportion in their blood.
All the old theories about the mechanical action of decompres-
sion should have disappeared entirely, and it really should be
enough to show their folly to recall the experiment in which I
went down to the fatal pressure of 248 mm. without the least in-
convenience, under the single condition of restoring the oxygen
tension to its normal degree by breathing an artificial super-
oxygenated air.
Decreased Pressure 981
The question then appears to have been reduced to a remark-
able simplicity; but though the cause of the phenomena observed
can thus be expressed in a word, its consequences are so diverse
that they deserve to be studied in the different conditions in which
the diminution of pressure can act.
1. Aeronauts.
Let us begin with the simplest case, and let us consider first
the aeronaut, who, without making any effort, is lifted in the up-
ward course of his balloon.
As he rises and the pressure diminishes, his blood loses its oxy-
gen, as my experiments have shown: a very slight weakening at
first, whose existence, nevertheless, my analyses have permitted
me to prove as soon as the pressure is not more than 56 centimeters.
Even then, the oxygen loss cannot have a very definite immediate
effect; the difference is like those one observes between individuals
who are in equally good health, like those which changes in respira-
tory rhythm or the different states of activity or of rest, of diges-
tion or of abstinence bring in the same individual. The aeronaut
cannot feel it.
If he rises higher, the loss of oxygen increases: at 2000 meters it
was on the average 13%; at 3000, it becomes 21%; at 6500, 43%; at
8600 meters (26 centimeters pressure), the height at which Croce-
Spinelli and Sivel died, they must have lost half of the oxygen of
their arterial blood. My animals at 17 centimeters pressure had
lost 65%; their arterial blood then contained only 7 volumes in-
stead of 20 per 100 volumes of blood, less than ordinary venous
blood coming from a contracted muscle. This is the blood which,
in the arteries, was given the task of nourishing and animating
the muscles, the spinal cord, the sense organs, the brain! In con-
sidering these facts, we recall the celebrated experiment of Bichat,
on dark blood injected into the vessels of the nervous centers.
We know that, in a general way, the effects of the rarefaction
of the air began to be felt quite plainly about the height of 4000
meters, corresponding to a pressure of 46 cm. It is also at about
this pressure that in our bells our animals ceased to move about
and showed signs of discomfort. Now the graph of Figure 31 shows
that at about this moment the proportion of oxygen in the blood
diminishes more rapidly; there is a remarkable agreement here.
This decrease in the quantity of oxygen contained in the blood
is the prime factor. From it are derived all the symptoms of decom-
pression. Its cause, we have seen, is double: first, the proportion of
982 Summary and Conclusions
oxygen which the blood can absorb grows proportionately less as
the pressure lowers (See Part II, chapter II, subchapter V) ; in the
second place, if we suppose that the respiratory rhythm has not
changed, the quantity of oxygen which circulates in the lungs
during a given time diminishes in the same proportion as the pres-
sure. Now under normal pressure, the arterial blood, we have
seen, is never completely saturated with oxygen, the agitation of
the blood and the air not taking place with sufficient energy in the
lungs.
The deviation must increase greatly when not only the coeffi-
cient of the oxygen absorption but also the intra-pulmonary cir-
culation diminishes. Indeed, at a half-atmosphere, for example, to
keep the conditions of intra-pulmonary mixing as they were at sea
level, everything must be doubled: the respiratory movements
must be double in amplitude and frequency; the heart beats must
be double in strength and number. That is evidently impossible.
However, there is a tendency in this direction, as the accounts of
all the aeronauts give witness, as I have observed in the animals
and experienced myself in my apparatuses; at low pressures the
respiration quickens, the heart beats are stronger and more rapid,
and equilibrium can be nearly reestablished. We have seen, in
fact, that if the pulmonary ventilation increases, the arterial blood
may gain 3 or 4 volumes of oxygen per 100 volumes of blood.
But this can be only momentary, and such gymnastics cannot
long continue without danger of emphysema and cardiac maladies;
and so this increase does not last, and when the balloon becomes
stationary, this dangerous acceleration does not continue in the
aeronauts: the oxygen then decreases fatally in their blood.
Furthermore, when the pressure diminishes still more, the respir-
atory and circulatory acceleration not being able even for an in-
stant to compensate for the insufficiency of the intra-pulmonary
agitation of the air and the blood, the muscles of respiration, like
those of the heart, lose their energy and grow weary, since they
are receiving a blood that is insufficiently oxygenated, and yet are
compelled to carry on continuous labor. The respirations, always
numerous during activity, are shallow, so that the quantity of air
inspired in a given time is hardly the same in volume as at normal
pressure; in rest, they fall back to their ordinary number, while
remaining very shallow, and it even seems, according to the remark
of de Saussure, that one sometimes forgets to breathe. The heart
movements give similar results; their frequency increases, it is
true, but the cardiac tension drops considerably; in one of the
Decreased Pressure 983
sphygmographic graphs of M. Lortet, taken just as he arrived at
the summit of Mont Blanc, it is hard to find indication of the pulse.
And so the organism, conquered in its struggle to compensate
for the diminished density of the oxygen in the air by agitation
of the air and the blood, returns to the regular routine of its move-
ments, which the poverty of the blood soon weakens. At this time,
the seriousness of the phenomena begins to increase rapidly; the
blood's insufficient capacity for oxygen is complicated by a greater
and greater imperfection in the intra-pulmonary ventilation and
circulation caused by the insufficiency of the oxygen absorbed.
That is why, as we have seen, the arterial blood of animals under
decompression contains even less oxygen than it might absorb at
that given pressure.
This rapid decrease in the oxygen content of the blood causes a
profound disturbance in metabolism and consequently in the func-
tioning of the organs. We have seen that in animals placed under
bells with rarefied air, when the decompression is great enough,
the quantity of carbonic acid exhaled and of urea excreted dimin-
ishes considerably; the temperature drops also, even when that of
the outer air is average. The same thing must certainly happen to
aeronauts, when they reach very great heights, where, in addition,
the air is generally very cold. I recall that I showed experimentally
that in cold air, resistance to decompression is less than at ordi-
nary temperatures.
But under decompressions lower than those which we had to
use to show experimentally, that is, roughly, the diminution of the
inner workings of metabolism, it is revealed to the observer by the
functioning of the organs. But here, as is always the case when
we have to do with a cause capable of affecting the whole or-
ganism, it is. the nervous system which reacts first, which is the
first to complain, if I may use this expression. The sensation of
fatigue, the weakening of the sense perceptions, the cerebral symp-
toms, vertigo, sleepiness, hallucinations, buzzing in the ears, dizzi-
ness, pricklings, reactions of the pneumogastric and sympathetic
nerves, nausea, palpitation, dilation of the arterioles are the signs
of insufficient oxygenation of central and peripheral nervous or-
gans. After the nervous system comes the muscular system, which
betrays weakness, is seized by convulsive contractions, and by
shudders, in which the nervous system also certainly has its part.
Finally, in the last stages, come paralysis, syncope, or to speak more
exactly, loss of consciousness, and finally death without a last sigh
984 Summary and Conclusions
and without convulsions, if the diminution of pressure has not
been brought too suddenly to its fatal degree.
The symptoms of decompression disappear very quickly when
the balloon descends from the higher altitudes; very quickly also,
as I have often seen in my experiments, the normal proportion of
oxygen reappears in the blood. There is an unfailing connection
here.
No less striking is the correlation between the data observed in
balloon ascensions and those in the only two known cases in which
men have been subjected to air with low oxygen content, without
the interference of carbonic acid. The first was observed, as I
have already said, by M. F. Leblanc in the pyrites mines of Huel-
goat in Brittany. In a gallery in which the air contained only 9.8%
of oxygen, and which he entered without transition, he had at-
tacks of vertigo and fainting. Now that oxygen tension nearly
corresponds to that of the air at a height of 6000 meters, where
certainly balloon sickness would violently attack anyone who ex-
posed himself to it suddenly. The second, observed by M. Forel,
is particularly noteworthy because of the similarity of the mental
symptoms which he experienced in air with a low oxygen content
and those from which I myself suffered under a decompression
corresponding to the height of Mont Blanc.
The moment at which aeronauts feel and the experimental ani-
mals manifest serious disturbances varies, as we have seen, not
only with the species, but with individuals in the same species.
The analysis of the gases of arterial blood shows us inequalities
quite of the same order, which certainly are the immediate cause
of these differences. At a pressure of 36 cm., one of my dogs (Ex-
periment CLXXI, number 10 of Table X) had lost 55.6% of the
oxygen of his blood, another (Experiment CLXXIV, number 11)
having lost only 36.1 (Table X, column 14) ; they had, however,
reached about the same figure (8.5 and 8.9, column 8). Another
of my dogs showed (Experiment CLXX, numbers 2 and 5) a very
remarkable resistance: at 56 cm. he lost only 3.2% of his oxygen;
at 46 cm., only 5.5, keeping the high proportion of 20.3.
A careful inspection of Table X shows many interesting in-
equalities in this point; but we cannot find the reasons for these
inequalities. Neither the vigor of the animals nor the original
oxygen content of their blood can serve in themselves as an ex-
planation. Nevertheless, by considering the general results of the
analyses of the blood gases, one can account fairly well for these
phenomena.
Decreased Pressure 985
In the first place, we know that, between two animals of the same
species, adult and in good health, the oxygen content of the arterial
blood is very variable; the variations, in our analyses, have been
(See Table XX) from 14.4 to 22.8 volumes of oxygen per 100 vol-
umes of blood; it seems evident then, a priori, that two animals
presenting this difference will not behave in the same way in re-
gard to decompression, and that the first will be more rapidly
affected than the second.
In the second place, if we imagine two animals identical in the
oxygen content of their arterial blood, it may be that they are not
identical in the maximum capacity of their blood for oxygen; one
may be already nearly saturated, the other still far from his point
of saturation. The latter then, by speeding up his respiratory and
circulatory movements, can go further towards saturation and con-
sequently resist decompression better. But that is not all; since
he has the same quantity of oxygen, although not saturated, his
blood contains in an equal volume more hemoglobin than that of
the first, and this hemoglobin is less oxygenated. Now everything
shows that the oxy-hemoglobin is hard to dissociate, either in the
pump, or by the tissues, in proportion to its distance from its
saturation point. Our animal, for this reason too, will lose in
decompression less oxygen than the one which nevertheless had
the same quantity in the blood.
We can go further yet: two animals of the same weight and
identical in the oxygen content and degree of saturation of their
arterial blood may differ considerably in the quantity of blood con-
tained in their vessels. And if this is so, it is clear that if, in a
given time, they consume the same quantity of oxygen within
their organisms, the blood of the one which has the least will give
up to the tissues the greater proportion of oxygen; in other words,
there will be a greater difference from the point of view of oxygen
content between his venous blood and his arterial blood than in
the animal with the greater quantity of blood. In our experiments
we have observed differences of this sort; we have seen, for ex-
ample, a certain dog have in his venous blood 9.2 volumes of oxygen
less than in the arterial blood (Exp. CXC) ; another (Exp. CXCII)
has only 3.3. If we suppose all other conditions identical, and if
we subject these two animals to a considerable diminution of
pressure, it is clear that the first will be painfully affected long
before the other, because his venous blood has a much smaller
reserve of oxygen.
Now we reach the very foundation of the question. Let us con-
986 Summary and Conclusions
sider an individual whose arterial blood contains 20 volumes of
oxygen, per 100 volumes, and whose venous blood contains 12,
an individual who consequently for the needs of his organic com-
bustions consumes 8 volumes. of oxygen borrowed from his ar-
terial blood. Let us now suppose him subjected in a balloon to
the effect of diminished pressure. The oxygen of his arterial blood
will decrease progressively as we have seen, and naturally the same
thing will be true of his venous blood. But he will pass through
two successive phases which we should study carefully. In the
first, the impoverished arterial blood, in spite of the compensa-
tory efforts attempted by the respiratory apparatus, will drop to
18, 16, 14 volumes of oxygen; that is when — if we take as a basis
of our calculations the graph of Figure 31 — the pressure has been
lowered to 62, 48, 40 cm., corresponding approximately to elevations
of 1600, 3600, 5100 meters. If there is no change in the intensity
of his intra-organic combustions, our aeronaut will still need the 8
volumes of oxygen which he consumed at normal pressure, and his
venous blood will contain 10, 8, 6 volumes of oxygen. These figures
represent degrees of saturation of the hemoglobin which are easily
dissociated for the needs of organic combustions; the quantity of
oxygen necessary for the inner phenomena of metabolism will have
been found, and nothing will be changed in the general equilibrium
of our aeronaut. Of course, his tissues will be bathed in a blood
relatively low in oxygen; but as they can extract from it what they
need, although with a little more difficulty than in the normal state,
nutritional disturbances with their functional consequences will be
only slight.
But the balloon is still rising and reaches successively 5700
meters (37 cm.) , 6600 meters (33 cm.) , 8600 meters (26 cm.) ; the
oxygen of the arterial blood drops to 13, 12, 10 volumes. Then it
becomes more and more difficult to find the 8 volumes of oxygen
necessary for the regular maintenance of the organism, for the
venous blood must fall to 5, 4, 2 volumes, and the oxy-hemoglobin
shows itself more and more rebellious to reduction. In fact, ex-
perimentation has shown that this reduction does not take place;
the graphs of Figure 40 are very characteristic and show that the
oxygen consumption lessens in the organism, the difference dimin-
ishing between the graphs, till then parallel, which represent the
oxygen content of the arterial blood and that of the venous blood
at different pressures. Then, simultaneously, we see diminishing
in growing proportion the quantity of oxygen consumed from the
air, the carbonic acid expelled, and the urea excreted; then too the
Decreased Pressure 987
temperature begins to drop. Then, consequently, there appear,
with an equally growing intensity, serious physiological disturb-
ances, due to the insufficiency of the quantity of vital force set at
liberty; the respiratory muscles, the heart, which till then had
struggled to. carry on the metabolism, fall exhausted, so to speak;
the whole muscular system, the venous system, which can hardly
find in the impoverished blood the oxygen strictly necessary for
their static maintenance, can carry on no energetic or lasting work.
And, by the usual series of sympathies, of organic harmonies, that
which was effect becomes cause in its turn: the chilled tissues
become less fitted for combustion: the sluggish and weakened heart
no longer pumps the nourishing liquid with the same abundance,
and the unhappy aeronaut, dragged on in this sort of vicious spiral,
rapidly descends the slope which leads to death.
So, in summary, two phases: phase of struggle, phase of defeat,
with a passage from one to the other whose duration will vary
according to many circumstances, which we shall rapidly review.
We can divide them into two classes: some are inherent, others out-
side the person under observation.
Among the inherent circumstances, we have already mentioned
as favorable the abundant blood supply of the organism, the large
oxygen content of the blood, the great capacity of the blood for
oxygen, and the smallest relative consumption of oxygen in the
blood as it passes through the tissues. There are others also, and
important ones, which we do not understand as clearly at first,
and which depend on the chemical state of the tissues themselves.
Another possibility is, when the quantity of oxygen brought is
very small, a tissue in which rest has permitted an accumulation
of materials that are easily oxidizable, or a tissue drained of these
materials by previous functioning that was too energetic. In the
first, everything will be ready for a maximum utilization of the
oxygen brought, and consequently for a maximum output of vital
force; in the second, on the contrary, beside the phenomena of
discharge of vital force and of combustion, the organic equilibrium,
lowered to its very limit, will require reductions, the storing up of
vital force which will lessen by so much the total available for
outlay in heat and work. In addition, the digestion, which gives
the organism materials easy to oxidize, must establish a condition
favorable to the preservation of a state compatible with strength
and health. Finally, to end what pertains to the inherent cir-
cumstances, we shall mention the disastrous effects of muscular
or intellectual efforts, which, requiring for their accomplishment
988 Summary and Conclusions
a sudden consumption of oxygen, take from this blood, which is
already so poor, the insufficient supply intended for the nourish-
ment of the tissues, and reduce these tissues to poverty and im-
potency; but this discussion belongs rather in the study of the
symptoms of mountain travellers.
First among extrinsic and unfavorable circumstances we must
mention the cold. Aeronauts have encountered extremely low tem-
peratures. Now, since the immortal works of Lavoisier, everyone
knows what super-activity in oxidations can be required for the
maintenance of a constant temperature. It is clear that in the
difficult conditions in which the source of oxygen, that is, the
arterial blood, is involved, the moment when the organism is
threatened can be hastened by the action of an intense cold. But
the patient must already, or nearly, have reached the phase of or-
ganic depression, without which the compensating action of the
same physiological means which permit us, at ground level, to
resist cold, would be able to work effectively in the upper strata.
A second dangerous circumstance is too great rapidity in the
ascent. However confused our ideas still are in regard to the
effects of habit, it is quite certain that modifications in our condi-
tions of life have much more painful consequences when they are
sudden than when they are brought on somewhat slowly; this fact
is very clear in the case of diminution of pressure, and we have
often seen in our experiments an animal suddenly overwhelmed
by a decompression to which we could have brought him easily
if we had made the transitions prudently; besides, this animal, if it
is not killed immediately, recovers more or less completely under
the same decompression which had almost been fatal to him.
Up to now we have spoken only of the oxygen of the blood.
Can it be that the other gases, whose proportion diminishes
equally, play some part in the symptoms of decompression? Car-
bonic acid, whose diminution in the blood advances even more
rapidly than that of oxygen (See Fig. 31), does not seem to me
important in the case of aeronauts, who remain for so short a
time under the influence of decompression; we shall return to
that point when we speak of mountain dwellers. As for nitrogen,
it enters into the question only from the mechanical point of view.
We have shown the formidable part it plays in sudden decompres-
sions from several atmospheres on; but it seems to me impossible
to attribute the slightest unpleasant influence to its release during
even the most rapid balloon ascension: Coxwell and Glaisher took
50 minutes to arrive at an altitude of 8838 meters; Croce-Spinelli,
Decreased Pressure 989
Sivel, and Tissandier in two hours reached the height of 8600
meters, the decrease in pressure being about three quarters of an
atmosphere. Now we have seen that even the slightest symptoms
of sudden decompression never appear for an almost instantaneous
decompression from one atmosphere; beyond, for decompressions
from several atmospheres, twenty minutes per atmosphere give
protection from symptoms; we are far from the conditions pre-
sented by aeronauts.
We now understand perfectly the phenomena the aeronaut will
present as he rises in his balloon. At lower heights, a slight ac-
celeration of the pulse and the respiration attempting to compen-
sate for the diminution of oxygen which the blood begins to un-
dergo, an acceleration which seems to have some of the con-
sequences of fever, as it has some of its symptoms. At this time, in
fact, observers have noted a certain intellectual excitement, with
a feeling of well-being, of lightness, of strength, which I do not
think should be ascribed solely to the excitement of the trip, or
to the splendid spectacles offered to the admiration of the aeronaut
by the clouds lighted from above by the sun. I think that the
increased activity of the circulation, subjecting the organs and par-
ticularly the nervous centers to a more rapid irrigation, takes from
them more completely the waste products of metabolism and by
this sort of washing puts them in conditions most favorable for
their functioning. On the other hand, not only the carbonic acid,
but all the gaseous impurities which our blood absorbs at ground
level, particularly in the air of large cities, escape in an already
considerable proportion, and our organs, so sensitive to the influ-
ence of these noxious matters still mostly unknown, must ex-
perience advantages easier to divine than to define precisely.
But the balloon continues its upward course: it reaches and
passes 5000 meters. The oxygen diminishes in the blood in con-
siderable proportion, although enough is left for the necessary
consumption. The enthusiasm, the feverish excitement ex-
perienced about 2000 meters have nearly disappeared; the heart
beats rapidly; movements become rather painful, the cold is felt.
Higher yet, rest becomes indispensable; the impoverished blood,
can no longer provide the increase of oxygen required for muscular
contractions; so the least effort causes panting, palpitations; the
sturdy Sivel can hardly lift a bag of sand weighing 20 pounds to
the level of the basket; drowsiness overcomes the passengers; they
have vertigo, buzzing in the ears, dizziness; the sky appears almost
black, partly because of the weakness of vision. Finally, higher
990 Summary and Conclusions
yet, if, in the midst of a sort of muscular., sensorial, and intellectual
inertia of which they are victims, they wish to make even a slight
movement, to raise an arm like Glaisher and Tissandier, they sud-
denly perceive that paralysis has struck them unawares, and almost
immediately, since the brain to which a weakened heart sends a
blood insufficiently oxygenated ceases its duty, there comes a loss
of consciousness which, if the balloon does not descend, may lead
rapidly to death.
Prophylaxis. The analysis which we have just made shows the
usefulness of a certain number of precautions which common sense
had already suggested. Aeronauts planning very lofty ascensions
ought as much as possible in the preceding days to avoid excess
of muscular, nervous, and intellectual fatigue. Although in good
health ordinarily, especially from the point of view of respiratory
and circulatory organs, they must guard against attacks of bron-
chitis, which hinder the respiration. Before starting, they should
take a meal of substantial food and take with them some cheering
victuals to eat frequently on the way.
They should try to arrange everything in the basket so as
to avoid making great muscular efforts; the bags of ballast, for
example, should be emptied by cutting a cord, and not lifted from
the bottom to the edge of the basket. A comfortable arrangement
will not be simply luxury, it will save the consumption of oxygen.
Let us add that rugs, bottles of hot water or, better, hot oil,
should be taken along to keep away the cold, which also consumes
oxygen.
Prudence would dictate that they slacken the ascent when they
reach the upper strata, so as not to be subjected to over-sudden
changes. Unfortunately that is almost never possible in practice,
for if the course of the balloon is slackened, the gas contained in
it will grow cold on contact with the icy layers of the air, and
the balloon will lose part of its ascensional power. Now there is
never too much for such expeditions, and as much ballast as pos-
sible must be kept for the accidents of the descent, in which the
balloon, almost empty, behaves almost like a simple parachute.
Such are the precautions whose utility was observed before
my work. But today, though still useful, they are far less im-
portant than the respiration of superoxygenated air. Thanks to
this, and to this alone, all the dangers of decompression can be
braved with impunity. I have verified this experimentally upon
myself, as you have seen,
Decreased Pressure 991
To be completely safe it is necessary only to breathe an air
whose oxygen content rises proportionately as the pressure falls;
so that the oxygen tension may always remain the same, or at
least always be equal to, if not higher than, that which exists in
the air at normal pressure. In balloon ascensions, nothing is
simpler to carry out, since space is not wanting.
Therefore there should be fastened to the ring of the balloon
two bags of goldbeater's skin, one of which, filled with a mixture
containing 70% of oxygen, will serve for heights from 5000 to 7000
35
meters: oxygen tension at 6000 meters = 70 x — = about 32. The
76
other, as pure as possible (95% in practice), will serve for the
greater heights: at 9000 meters, the oxygen tension of the mixture
24
will be about 95 x — = 30, that is, it will be double that of ordinary
76
air at 2700 meters. The size of the bags should be calculated to
provide 10 liters per man and per minute of stay in dangerous
regions; so, in the fatal and glorious voyage of the Zenith, to avoid
all danger and gain advantage from the whole ascent, they should
have taken 1300 liters of the first mixture and 1800 liters of the
second,23 that is, about 3 cubic meters in bags of a 9 meter capacity,
because of the extreme expansion of the gas at these heights. But
this quantity, I must say, would have been absolutely the maximum.
1 cannot recommend too strongly that at 5000 or 6000 meters a
direct and compulsory connection be made between the oxygen
bags and the mouths of the aeronauts, by means of a mouthpiece
like those of the Galibert or Denayrouze apparatuses. If such a
precaution had been taken for the Zenith, there would have been
no disaster to deplore; simply recall the touching account of M. G.
Tissandier: "I wanted to seize the oxygen tube, but I could not
raise my arm." If he had had the tube in his mouth, they would
all have been saved!
2. Mountain travellers.
The conditions in which mountain travellers are placed differ
from those of aeronauts in two important points: A. the muscular
efforts required by the act of ascent; B. the relative slowness of
the ascent and the duration of the stay in lofty places.
992 Summary and Conclusions
A. Muscular effort. The muscular contractions and the produc-
tion of work necessary to raise the weight of the body require an
active consumption of oxygen, for which, at ordinary levels, the ac-
celeration of the respiration would suffice. But when the quantity
of oxygen in the blood is considerably lowered, the new expendi-
ture cannot be met without serious disturbances.
And so it is not surprising to see mountain sickness appear at
levels considerably lower than balloon sickness; it is generally
quite pronounced at 4000 meters (46 cm. pressure) ; almost everyone
experiences it at the top of Mont Blanc (4800 meters; 41 cm.).
Most of the travellers in the Andes and the Himalayas feel most
acute suffering when they pass above the height of 5500 meters
(38 cm.) , as did the brothers Schlagintweit when on Ibi-Gamin
they reached 6880 meters (32 cm.) ; and yet these brave travellers
were already acclimated by a long stay in lofty regions.
The data furnished in my experiments by the birds which, on
account of their restlessness, were threatened by death in a de-
compression which hardly affected their more quiet neighbor; the
impossibility of moving at a certain stage of decompression, and
in travellers, the extreme lassitude, the necessity of stopping at
almost every step, the amelioration which follows rest, especially
horizontal rest, all these things are entirely explained by the
knowledge we have of the scanty oxygen supply of the blood at
great elevations.
Our analyses of the gases of the blood permit us to reject a
posteriori, as we have already done a priori, the theory of M.
Gavarret on the poisoning of mountain climbers by the excess car-
bonic acid which they have produced. We have seen, in fact, even
in the animals which have been insecurely fastened on their board
or table, and which contract their muscles strongly in constant
movements, that, far from increasing, the carbonic acid always
diminishes.
Let us examine now more closely the question of oxygen con-
sumption, and let us compare our mountain traveller to the aero-
naut of whom we spoke before: let us suppose, for the sake of
convenience, that it is the same individual, having at normal pres-
sure 20 volumes of oxygen in 100 volumes of arterial blood and 12
volumes in venous blood. Imagine him transported to 3600 meters
and at rest; his arterial blood will contain 16 volumes, his venous
blood 8 volumes, supposing that there is no change in the intensity
of the metabolic processes and that no functional trouble has de-
veloped. But now he contracts his muscles, walks, and continues
Decreased Pressure 993
to ascend by a series of efforts requiring a consumption of oxygen.
Since the research of Claude Bernard, corroborated by that of Lud-
wig and Sczelkow, we know that there is a difference of about 12
volumes per cent of oxygen between the arterial blood entering
a muscle and the venous blood leaving it during the contraction, a
difference that amounts to only 8 volumes while the muscle is at
rest. If then we suppose that all the consumption of the oxygen
of the traveller's blood is due to muscular metabolism which is
increased in the proportion of 8 to 12, the venous blood should
contain only 12: 8 = 8: x = about 5 volumes of oxygen; at 5100
meters, the oxygen content of the venous blood should fall from
6 to 4, as the muscles pass from the state of repose to the state of
general contraction; at 6600 meters, it would be reduced to 1.3; and
all we said above about the difficulty of dissociating the weakly
oxygenated combinations of the hemoglobin, shows the dangerous
consequences of this exhaustion which our calculations show must
take place. Either the exhaustion will be complete, and then the
blood which returns to the right heart will be entirely stripped
of oxygen and the respiratory exchanges will restore to the arterial
blood only a quantity of oxygen that is still less than what was
there after the period of rest; or the exhaustion will be hindered
by chemical difficulties, and then the muscle, not being able to
find a sufficient quantity of oxygen, will stop in its contraction.
For one or the other reason, the traveller, after a few steps, is
forced to stop immediately, under pain of asphyxia: so he stops,
and the venous blood which leaves the muscles in repose, still con-
taining a considerable quantity of oxygen, can go into the lungs
to take up what the physico-chemical law of dissociation permits
it to take into the expanded gaseous medium. When the percentage
has risen sufficiently, a new effort is possible, followed soon by
another halt. This has happened to all travellers in lofty regions,
as the data reported in the historical part of this book prove super-
abundantly.
Of course the calculations which we have just made give exag-
gerated results in this sense, that the body is not all muscles, and
that not all the muscles contract at once in the act of ascent. But
on the other hand, we have spoken only of static muscular con-
traction, without taking account of work to be done. Now it is
probable, without our being able to consider this allegation as
demonstrated today, that a muscle which produces work while it
contracts consumes more oxygen than a muscle which contracts
statically.
994 Summary and Conclusions
If, in fact, the consumption of oxygen was the same in both
cases, the heat of the muscle should be less when there is work
produced; now, Heidenhain has shown that on the contrary it in-
creases, which demands a greater consumption of oxygen. We are
therefore justified in believing that the elevation of the weight of
the body in the act of ascent increases still more the amount of
oxygen taken from the venous blood by the muscles contracting and
consequently increases the distress of the organism.
This explains the well-known fact that in lofty regions, while
walking on a level is easily endured, the ascent of the smallest
hills brings on serious disturbances.
What we have just said of the mountain traveller, and what we
said before of the aeronaut, permits us to handle the question of
the chilling of the body during the act of ascent. The theory of
Lortet and Marcet states that, in conditions of decompression where
the temperature remains constant in a state of repose, it drops
when the ascent, which requires enormous mechanical labor, pro-
duces it at the expense of the heat developed by the organic oxida-
tions. I shall say first that in my opinion there is no transforma-
tion of heat into mechanical force in the organism; everything
seems to me to show that when forces of tension are set free under
the form of vital force in consequence of oxidative processes, heat,
electricity, and work are produced at the same time, in proportions
which vary of course, but whose variations are initial and do not
depend on subsequent transformations. We must then ask our-
selves whether it may be, not that heat is transformed into me-
chanical energy, but that the forces of tension, as they develop,
give out less heat in order to meet the requirements of mechanical
labor. When the question is put in this way, we must confess
that up to now the observations which bear out this theory can be
challenged, since the buccal thermometer cannot give accurate
results while walking is continued. M. Forel, in a recent work, and
M. Calberla, who took the rectal temperature, have always ob-
served an increase of temperature during the act of ascent. And
yet, I am persuaded that in higher regions, the statement of M.
Lortet would be verified. In our experiments we have seen mo-
tionless animals grow cold as a result of the diminution of pressure;
I am persuaded that if, at that moment, we had exacted of their
exhausted organism a production of mechanical work, their tem-
perature would have dropped still more, because, having already
passed the limit of equilibrium and having shown themselves
unable to oxidize their organism sufficiently to keep it in the ranks
Decreased Pressure 995
of animals with constant temperatures, they would not have been
able to release the necessary increase of tension strength, and
consequently they would have had to deduct from the production
of heat the vital force necessary to execute this work. Now it is
possible that even at the limit, when the temperature still remains
normal during rest, there is a slight drop in it at the moment of
the new expenditure required by the vertical propulsion of the
body. I cannot stress too strongly the interest which would be
presented by thermometric researches carried on, with all neces-
sary precautions, and during the act of ascent, upon persons already
suffering severely from mountain sickness; but perhaps our Euro-
pean mountains are not high enough to permit us to observe a drop
of temperature, even in these conditions.
It has been thoroughly demonstrated, at any rate, that chilling
of the body is not the cause of mountain sickness, which occurs
without modification of the inner temperature.
I do not mean, as I have observed in speaking of aeronauts, that
exterior cold plays no part in the matter of mountain sickness.
On the contrary, its importance is great because it increases the
oxygen requirements of the organism which is struggling to pre-
serve its equilibrium. Indeed it is evidently this necessity of
struggling against cold, a new cause for the consumption of oxygen,
a new cause for the impoverishment of the blood, which explains
why, in our icy Alps, mountain sickness strikes most travellers at
heights which are quite harmless in the Cordilleras; here, the limit
of perpetual snows is 4800 meters; there, only 2700. Provision
must be made for warming the body at the same time as for the
muscular efforts of the ascent.
B. Duration of the Ascent. The duration of mountain journeys,
much longer than that of balloon ascensions, is a favorable con-
dition, as we said when speaking of the ascensions. The traveller,
compelled to mount the slopes slowly, avoids the harmful effect
of sudden modifications in the oxygen content of the blood; he can
hardly in a day's march mount more than 3000 meters, and then, if
he has not reached the summit, he must rest, pass the night, in a
word, become accustomed to the state of anoxemia he has reached.
This is so true that in the first part of this book we could have
explained a part of the peculiarities of mountain sickness in the
different regions of the globe by the form of the mountain mass,
or the more or less isolated situation of the peak to be climbed.
We have also shown how a better use of muscular strength, due
to the habit of exercise in the mountains, explained the much
996 Summary and Conclusions
greater resistance to the sickness presented by travellers after a
few preliminary ascents: the expenditure of strength is thus re-
duced to its minimum.
For all these questions, for the influence of fatigue, of cold, etc.,
we refer to the summary already presented of data that have long
been known (pp. 315-328). Now that we know that everything is
explained by the diminution of the oxygen of the blood, we under-
stand how a useless excess of muscular contractions can more
rapidly bring the anoxemia to its asphyxiating degree, and cause
the sickness.
As to bad or insufficient nutrition, it is clear that if the oxidable
materials are not furnished in suitable quantity, the difficulties of
the organism, in the expanded air, in maintaining the necessary
combustions, will be increased by so much. But there is nothing
there, except the intensity, which is peculiar to lofty places; the
expenditure upon which M. Dufour has justly insisted will take
place to the same degree in every ascent, whether it is below 1000
meters or above 4000, and yet the subsequent phenomena will be
very different.
As to a more precise analysis of the causes and the value of
acclimatization, it seems to me that it will be better placed in the
following section, when I speak of the dwellers in high places.
Prophylaxis. To take precautions against the cold, to eat suit-
ably, to reduce muscular efforts to their minimum, to train oneself
by preliminary ascents and by a prolonged stay in lofty regions, to
spend the night before the main ascent as high as possible, not to
hurry on steep slopes, to break the ascent by frequent halts, to eat
little and often, such are the general precautions suggested by all
we have said.
The use of oxygen, that sovereign protector against the dangers
of rarefied air, here presents much greater difficulties than for
balloon ascensions. It is impossible, of course, to carry bags of
oxygen containing several cubic meters up a mountain. Only two
means present themselves: to enclose in solid receivers the neces-
sary provision of oxygen, compressed to several atmospheres; or to
prepare the necessary oxygen extemporaneously on the spot, from
time to time.
To study the possibility of the first means, I applied to M.
Denayrouze, who put at my disposal an apparatus composed of two
cylinders of sheet steel one millimeter thick, capable of enduring a
pressure of 40 atmospheres, which one could carry on his back like
a tourist's pack: the two cylinders combined being only 36 cm. high
Decreased Pressure 997
and 26 cm. wide, and weighing with the Denayrouze regulator only
13 kilograms. The volume of the cylinders being 11 liters, one
would have at 30 atmospheres, a pressure which presents no dan-
gers, 330 liters of oxygen,24 which one would evidently have to
take as pure as possible, that is, in practice, at 95%. But since the
respiration of pure oxygen is not at all necessary, I had a tube
made in the form of a Y, which serves to mix in proper proportions
the oxygen of the receiver with the outer air; one of the branches,
which opens out, is free; the other, which communicates with the
cylinders, has a graduated bolt, by means of which its caliber is
narrowed more or less, according to specifications calculated in
advance, so as to maintain the oxygen tension at a sufficient degree.
Supposing that one breathes, on the average, air with 45% of
oxygen, the volume available would become 660 liters, which could
suffice for the continuous respiration of a man for more than one
hour. But in practice it would not be necessary to breathe super-
oxygenated air constantly. On Mont Blanc, the mountain in Europe
where these symptoms are at the maximum, this provision would
be enough for the most susceptible of travellers, and on the average
could guard two or three travellers from what is sometimes so
painful in mountain sickness; they would only have to come from
time to time, in difficult places, to breathe some whiffs of this
gaseous cordial, to drink some gulps of oxygen, according to the
picturesque expression of Sivel. But we see that the use of this
means would be rather difficult and inconvenient in very lofty
regions, where superoxygenated breathing should be almost con-
tinuous, and even, we must confess, dangerous, if a violent fall of
the man carrying it should break the apparatus.
It certainly would be much better to be able to produce oxygen
from time to time, at necessary halts, to meet the needs, instead of
storing it up in little bags. But I do not now know any chemical
reaction which can be managed easily without the transportation
of fragile or heavy instruments, or, in a word, in conditions practi-
cal for ordinary ascents. But scientific expeditions of long duration,
like those which sojourned for weeks in the lofty regions of Thibet,
Ladak, and Pamir, could and even should carry with them the
equipment necessary to procure oxygen under given circumstances.
It is rare, no doubt, that anyone dies exclusively from the effects of
rarefied air, although we have mentioned examples of this kind of
death; but its fearful influence increases rapidly the dangers of all
the maladies which jeopardize the oxidation of the blood. I am
998 Summary and Conclusions
convinced that if Dr. Stoliczka could have breathed oxygen from
time to time, he would not have perished thus in two days.
Whatever the difficulties of practical realization, it is certain
that, by the respiration of super-oxygenated air, the summit of
Mount Everest, the loftiest mountain of the globe (8840 meters),
is no longer theoretically inaccessible to man, since I myself with-
out impediment have reached the pressure of 248 millimeters, which
corresponds exactly with that of this prodigious height. Now at
this level Glaisher fell inanimate in the bottom of his basket, and
Croce-Spinelli and Sivel died 200 meters lower.
3. Dwellers in High Places.
We have seen in the first part of this book that human habita-
tions are found at the level of 4500 meters in South America and
the Himalayas; on the summit of Pichincha (4860 meters) hum-
ming-birds are numerous; the lapwing "seems at home" at 5500
meters on the high plateaux of Little Thibet. These are extreme
limits. Lower, between 2000 and 3000 meters, millions of men live
grouped in cities and nations, in conditions where dwellers on the
seashore almost always feel painful, sometimes unendurable, effects,
when they are suddenly transported there. Finally, on hills of
about 1000 meters, not only are there large populations, but the
dwellers on the seashore usually feel — at least for a time — more
active, more nimble, and stronger there than in their native haunts.
Let us examine successively these different points.
Slight heights. — We place their upper limit at about 2000 meters.
The impression which they produce upon the traveller who comes
to stay there for several weeks or months is, as we have just said,
generally favorable. Let us refer to what we said of the aeronaut
carried by his balloon to a corresponding level; the same observa-
tions will apply to our traveller. There should be first a tendency
to a decrease of the blood oxygen, a decrease for which the accelera-
tion of the respiration and the circulation will probably provide
sufficient compensation. These accelerations are real, as the obser-
vations of M. Jaccoud (p. 297) and M. Vacher (p. 960-1) prove. The
respiration even becomes more ample, "so as to set to work certain
indolent regions of the lungs which ordinarily take only a very
small part in the inspirational expansion; these regions are the
upper parts of the organs." According to Dr. Armieux (p. 298-9) ,
the result is a considerable increase of the thoracic capacity, whose
circumference gains an average of 2 to 3 centimeters. Now this
increased amplitude of respiratory movements is of great impor-
Decreased Pressure 999
tance; not only does it introduce a greater quantity of air into the
lungs in a given time, but this air is distributed better and more
usefully in the respiratory tree. M. Grehant -r' shows that, although
the coefficient of ventilation is 0.060 for inspirations of 300 cc, it
becomes 0.159 for inspirations of 600 cc, that is, much more than
double for double inspirations. So, he says, and this is not the least
interesting among the results of his fine studies: "Thirty-six in-
spirations of 300 cc. made in one minute (10.8 liters) will not
renew the gases of the lungs as well as 18 inspirations of a half-
liter each (9 liters) p. 537)." That is a consideration which we
have not taken into account till now.
The circulatory apparatus also comes to the rescue. M. Mer-
mod (p. 330) found that his pulse rate rose from 62 to 66, then to
68, living successively at 300, 600, 1100 meters of altitude. Now, as
we have said, the greater rapidity of the irrigation of the tissues
by the blood should on one hand compensate for the slight deficit
of oxygen, and on the other, diminish, by a sort of washing, the
proportion of organic wastes retained in the tissues.
Finally, the foreign volatile substances should disappear from
the blood, and the carbonic acid lessen there; this decrease is
slight, of course, since at 1500 meters (63 cm.) it should be about 3
volumes out of 40 (See Figure 31), supposing that all other con-
ditions are equal; but no one can state that it is absolutely unim-
portant, and we may think that it is, on the contrary, favorable to
the energy of the vital faculties. First, such a diminution takes
place in the venous blood (See Figure 40) , and consequently in the
tissues on which, as I have shown, this acid acts as an anesthetic.
We know, furthermore, that the functioning of the muscular and
nervous systems results in the formation of lactic acid, and that
the accumulation of this acid is very dangerous to the soundness
of the organic functions. Now we have seen that the arterial blood
almost never contains any dissolved COo, and that almost always,
on the contrary, its bases are not absolutely saturated with car-
bonic acid. If then the alkalinity of the blood increases, the effects
of the formation of lactic acid can more easily be compensated for,
and a feeling of better health may be the consequence.
Let us add that these changes in abode, generally planned for
reasons of health or pleasure, take the traveller from customary bad
conditions of life, subject him to baths of air, to exercise, to more
strengthening diet, make digestion easier, compel him to rest his
nerves, and stir his blood with the sight of the splendors of nature.
1000 Summary and Conclusions
all these circumstances being procured most satisfactorily by so-
journ in the mountains.
Great heights. But let us suppose our traveller transferred sud-
denly from the seashore not to Chamounix (1020 meters; 67 cm.)
or to Davos (1650 meters; 62 cm.), but to La Paz (3720 meters; 48
cm.) , or especially to Cerro de Pasco (4350 meters; 44 cm.) . If he
had, according to our usual hypothesis, 20 volumes of oxygen in
his arterial blood and 12 in his venous blood, and nothing else was
changed in him, he would have no more than about 16 or 14
volumes in the arterial blood, with 8 or 6 in the venous blood.
We have seen in the first part that, without the slightest doubt, at
Cerro de Pasco, especially if the action of the cold intervenes, he
will be attacked by the soroche (mountain sickness) , whose sever-
ity will be increased when he tries to walk, climb, or, like d'Orbigny,
waltz. The calculations which we made in the preceding section
in regard to mountain travellers, will give us a sufficient account
of these symptoms.
But very likely he will seem to become habituated progressively
to this state of affairs, especially at La Paz; after some time, he will
no longer feel the soroche when he is in a state of repose, and will
experience its disastrous effects only if he indulges in violent exer-
cise. He may even escape these entirely; he is, or seems to be,
as they say, acclimated. Is something changed in him then?
We might ask first whether, by a harmonious compensation of
which general natural history gives us many examples, either by a
modification in the nature or the quantity of hemoglobin, or by an
increase in the number of the red corpuscles, his blood had become
qualified to absorb more oxygen under the same volume, and thus
to return to the usual standard of the seashore. The dark color of
the blood observed formerly by Dr. Jourdanet during surgical oper-
ations would not be a positive objection to this hypothesis, since
we have seen that the red color of the blood depends not on the
quantity of oxygen it contains, but on the proportion between this
quantity and that of the hemoglobin. But it is very certain that
such a change, if it takes place, requires a very long time; it is even
probable that it can come about only through inherited disposi-
tions, and can come to complete development only at the end of
successive generations, so that it would explain the acclimatiza-
tion, not of the individual, but of the race. But even in this case it
is far from being proved; let us add that it would be desirable and
very easy 2G to test by direct experiment the hypothesis which I
propose without having any great confidence in it.
Decreased Pressure 1001
But after all, acclimatization, at least apparent, not only of na-
tives but also of temporary residents, is a certainty, when the
elevation does not exceed certain limits. How does it happen? To
say that they have become accustomed to these new conditions
explains nothing, although ordinarily we are compelled to use this
vague expression to designate everyday observations. How does it
happen that a certain day of average temperature seems to us warm
in winter, chilly in summer? That a certain room with closed
shutters is dark at first, whereas its slightest details are lighted
up after a few minutes? In the particular case we are discussing,
we understand very well that, on the one hand, organs accustomed
to being irrigated by an arterial blood with 20% of oxygen, accus-
tomed to live by borrowing from this blood 8 volumes of oxygen
easy to dissociate, complain and revolt when the arterial blood
brings them only 16 volumes, from which it becomes harder to
extract the 8 volumes necessary for inner consumption, and that,
on the other hand, at the end of a few days or weeks of more or
less painful transition, they progressively alter their first impres-
sion, exert themselves, and are more able to manage the somewhat
more difficult dissociation to which they are forced. But all this,
to tell the truth, is only a paraphrase of the expression "habit," and
explains little; we need to know what this inner modification of
the tissues consists of, and today we are unable to get the least
idea of it.
What is really certain is that this traveller, now a dweller in
lofty altitudes, does not even try to struggle against the decrease
of oxygen in his arterial blood by speeding up his respirations ex-
cessively, as was at first supposed. The observations of Dr. Jour-
danet are conclusive (p. 265). And that is easily understood. First
the gymnastics which one must perform to ventilate his lungs with
the same weight of air at 48 cm. as at 76 cm. evidently cannot be
kept up, even for a few minutes. In the second place, they would
hardly be effective, since our experiments have shown (See Figure
43, graphs B and C) that at this pressure saturation of the blood
by perfect agitation cannot add more than a volume and a half of
oxygen, and besides, at normal pressure, there is usually the same
average difference between the oxygen content of the arterial
blood and its maximum capacity. However a slight increase of
this sort would not be useless, and it could be produced either by an
acceleration or by a greater amplitude of the respiratory move-
ments. The first phenomenon does not take place, according to
M. Jourdanet; the study of the second would present great difficul-
1002 Summary and Conclusions
ties; one would have to place a gas meter on the course of the
inspired or expired air, observe the respiration for a very long time
to eliminate occasional modifications, and make observations either
on the same person alternately on the seashore and at a great alti-
tude, which would be the best but the hardest, or in a very great
number of persons to get averages.
If we suppose, as is probable, that the pulmonary ventilation has
changed little or not at all, and if, on the other hand, the organic
consumption has remained at the same degree, the result will evi-
dently be that the percentage in volume of carbonic acid in the
expired air will have increased in inverse proportion to the pres-
sure. At a half-atmosphere, in this hypothesis, it will have doubled;
at two-thirds of an atmosphere (50 cm. pressure, 3300 meters,
nearly the height of Cuzco) it will have increased by a third, and
the 4.3% average on the sea level have become 6.5; at Mexico
(58 cm.) , where Coindet made his unfortunately unprofitable ex-
periments (p. 266 and 277), it should be 58 : 76 = 4.3 : x = 5.6.
These are data which it would be easy to study on the spot; a flask
of 200 cubic centimeters in which one would make a score of expi-
rations, so as to renew the air in it completely, could, if provided
with a closely fitting heated rubber stopper, serve for distant
analyses; I would make this suggestion to travellers sojourning in
lofty regions, or even to mere mountain climbers.
But very probably the proportion for acclimated individuals will
be less than the calculation requires; in other words, very probably
the intensity of the respiratory combustions will have decreased.
And this probably constitutes what is called acclimatization in
lofty regions; I imagine that its cause is simply a lower consump-
tion of oxygen in a given time, an economy in the combustions,
which within certain limits does not hinder the completeness of
organic functions. I realize that I am leaving the solid ground of
direct experimental results to undertake a hazardous journey in
the unsteady realm of hypotheses; but what does it matter, if the
hypothesis leads us, not to imprudent conclusions, but to new and
fruitful researches? In this, as in so many other matters, nothing
ventured, nothing gained.
Let us see then.
Now I am persuaded that at normal pressure, we consume much
more oxygen in a given time than is necessary to maintain our
temperature at its normal and constant level, and to meet the de-
mands of forces required for muscular and nervous acts. Let us
examine the figures as the present state of science furnishes them,
Decreased Pressure 1003
but making reservations ~7 about the exactness of the values which
we are obliged to use; at least they give us an approximation.
Let us suppose that a man weighing 60 kilograms produces in 24
hours 2800 kilogram calories,18 and let us consider first the expendi-
ture of heat which he would need to maintain at the normal level
(on the average, 38°) the mass of his body in an air whose tem-
perature is 19°.
If we assume that this man admits to his lungs in 24 hours 12
kiloliters of air, whose temperature will be raised from 19°, we
shall find, since the calorific capacity of the air is 0.26, that there
will have been expended thus in calories 12 X 19 X 0.26 = 59.28
calories. The pulmonary evaporation of 500 grams of water (prob-
ably a maximum quantity) will necessitate a loss of 292 calories
(the heat of vaporization being 0.582) .
The heating of drink and food, the excretion of urine and the
faeces causes a loss of heat which Helmholtz estimates at 2.6% of
the total loss, here some 65 calories.
Here then is a known expenditure, which I admit is necessary,
of 59 -f- 292 + 65 = 416 calories. There remain about 2500 calories
lost; 1, by cutaneous radiation and the contact with the air; 2, by
cutaneous evaporation: this is on the average estimated at 1 kilo-
liter, consuming thus 582 calories. Are these losses justified, in the
circumstances in which we are placed, by the physical necessities of
maintaining at the temperature of 38° a body weighing 60 kilo-
grams, having about 13,000 sq. cm. of surface, with a caloric capacity
about equal to that of water, and surrounded by air at 19°? That is
what I should like to be able to settle here. Unfortunately, scien-
tific data at present do not permit us to settle this problem,29 and
we should have to undertake special researches on this point.
A priori, I cannot help believing that it is needless to lose by
simple cutaneous evaporation a kilogram of water per day, and
consequently 582 calories; this expenditure can be justified only by
an excess of heat produced, which radiation and contact cannot
throw off. How can we understand that heat is produced with the
sole purpose of losing it afterwards? This excess appears much
greater when we consider the human body producing work; the
unutilized heat becomes so great that an abundant sweat must
remove it by evaporation. Now it may very well be that mountain
dwellers have a better regulated machine, which, instead of de-
voting to work only 18% to 20% of the force expended, is con-
siderably more efficient, and consequently, for the same dynamic
expenditure, requires a smaller absorption of oxygen and of food
1004 Summary and Conclusions
We see that very probably, in the habitual conditions of our life,
we commit excesses of oxygenation as well as of nourishment, two
kinds of excess, which are correlative. And just as peasants, who
eat much less than we do, by utilizing all that they absorb, produce
in heat and work a useful result equal, if not superior, to that of
city dwellers; just as a Basque mountaineer furnished with a piece
of bread and a few onions makes expeditions which require of the
member of the Alpine Club who accompanies him the absorption
of a pound of meat, so it may be that the dwellers in high places
finally lessen the consumption of oxygen in their organism, while
keeping at their disposal the same quantity of vital force, either
for the equilibrium of temperature, or the production of work.
Thus we could explain the acclimatization of individuals, of genera-
tions, of races.
But we should consider not only the acts of nutrition, but also
the stimulation, perhaps less, which an insufficiently oxygenated
blood causes in the muscles, the nerves, and the nervous centers.
We have no measure of these factors, but it is probable that it is a
serious matter for these delicate organs, aside from questions of
oxidation, to receive an arterial blood containing 20 or only 16
volumes of oxygen, and we certainly may think that in the latter
condition, they will tend to be less active on the average.
The consideration of the changes in the carbonic acid content of
the blood, which we have somewhat neglected up to now, should,
it seems, take us longer, now that we are dealing with a long
sojourn. In the cities of an altitude of about 4000 meters, to which
in imagination we have transported our traveller, the carbonic acid
will, have diminished by 6 to 7 volumes, assuming that 40 volumes
are the average at sea level. The blood and consequently the tissues
will therefore become quite alkaline, and this modification must
have consequences whose importance we guess, without being able
today to determine their nature.
In fact, according to the observations of M. Jourdanet, the
dwellers in high places, even the native Europeans, are almost all
anemic,30 in spite of the appearance of health. Diseases, whatever
they may be, especially those which attack the respiratory organs,
hamper the absorption of oxygen, and bring out this sort of latent
anemia, due, not to the lessening of the number of corpuscles, but
to the lessening of their oxygenation, an anoxemia, adopting the
happy expression of my learned colleague and friend. Blood-
letting, to which one might resort in memory of medical practice at
Decreased Pressure 1005
low levels, is harmful, and tonics, on the contrary, are really
beneficial.
First among these tonics we should place respiration of an air
slightly superoxygenated or an air compressed so as to restore
normal tension. I am convinced that establishments like those of
Junod, or Pravaz, or Tabarie would render great services at Mexico,
La Paz, Cuzco, and Cerro de Pasco, especially to new-comers and
invalids.
But I shall stop now without drawing any conclusion. It has
been enough to show in what physiological conditions the dwellers
in high places must be, and how they can accustom themselves to
these serious disturbances. As to the reality and the soundness of
this acclimatization in individuals, from generation to generation,
and the apparent immunity of certain human races or animal
species, these are questions whose importance I understand fully,
but which devolve upon the hygienist or the naturalist, and whose
solution, besides, cannot be found in laboratory experiments. It is
upon experimental ground, which is familiar to me and on which
I am sure of my steps, that I shall obstinately remain.
4. Animal and Plant Life at High Elevations.
The native or imported animals which inhabit the lofty regions
of the Cordilleras and the Himalayas present the same problem as
the human beings of whom we have just spoken. With both men
and animals, the native born, species or races, have infinitely more
resistance than those who came to compete with them. The Indian
yaks, the American llamas can serve as beasts of burden without
suffering where mules and horses often die from the decompression.
Birds can rise still higher than mammals, the condor particu-
larly, which mounts in flight to 7000 meters, and soars for hours at
the heights at which the motionless aeronaut begins to feel serious
discomforts, and which the brothers Schlagintweit reached on the
mountain sides only at the cost of keen suffering due to the rarefied
air. Now in my decompression bells, birds showed themselves more
susceptible than mammals, and the birds of prey on which we
experimented were sick almost as soon as the sparrows. How can
we account for this double contradiction in incontestable data?
We have seen that the proposed explanations could not satisfy
us, and I confess that I have no other to propose. To attempt one I
should first need to master experimental data which are absolutely
unknown to me. First, I should have to try in closed vessels the
effects of decompression on condors, not menagerie birds, perhaps
1006 Summary and Conclusions
acclimated to the high barometric pressure of our country, but on
vigorous condors caught in their usual habitat: conditions difficult
to realize. I should also have to know the oxygen content of their
blood, and especially, as you can easily ascertain, since I have
indicated it above, its oxygen capacity. The amount of blood they
contain would also be interesting information. Nothing would be
more interesting, after all, than to try to establish their respiratory
and nutritional equation by air analyses, by weighing food, and by
calorimetric measurements.
Perhaps, after all this had been observed, it would be possible
to account for the strange resistance which they present to the
effect of rarefied air, even while they are performing the consider-
able work of ascent by flight.
In finishing this chapter, I shall recall the fact that plants, for
the same reason as animals, are affected by the lessened tension of
the oxygen which they respire in lofty regions. This element ha.i
till now been neglected by botanists, rightly preoccupied with the
study of the geographical distribution on the mountains, of the in-
fluence of temperature, of the intensity of the solar rays, and of
the hygrometric conditions. Usually they do not speak of it, or
they deny its importance. For example, M. Radau,31 mentioning
the fact that certain mountain plants cannot live in our country
with temperatures like those of their native land, says expressly:
"Atmospheric pressure has probably nothing to do with data of this
sort." But my experiments show that vegetation, and germination
perhaps even more, are markedly delayed in rarefied air.
They also bring to light a certain inequality of resistance among
different vegetable types, the cruciferae seeming less susceptible
than the grasses. Finally, and this is an interesting coincidence,
we have seen that the phenomena of vegetable life stop precisely
at the pressure of 7 cm. of mercury, which is fatal to all animals.
It is then at this low oxygen tension (2.5) that organic oxidations
in all living beings become so sluggish that they can no longer
maintain vital equilibrium.
5. Medical Applications.
I make haste to declare that I only suggest this point, which is
outside the scope of my studies. Dr. Jourdanet first had the idea
of using artificially rarefied air in the treatment of different dis-
eases, notably anemia and consumption (tuberculosis of the lungs) .
I refer the reader to his books for the study of the results obtained.
Both before and after him, residence at lofty heights has been and
Decreased Pressure 1007
is recommended especially to consumptives; this mode of treat-
ment dates, in the Andes, from the Spanish conquest, and according
to Tschudi, doctors abuse it so that "often the invalids lose their
lives in the Cordilleras." In Europe, only recently has sojourn in
lofty regions and particularly the Engadine been advised; but
already it is very fashionable, which proves that it is useful to
many society people and probably to invalids too.
I shall only call the attention of the doctors to the advantage
which might perhaps be derived in certain cases (fevers or inflam-
mations) from a decompression low enough to take from the blood
a considerable part of its oxygen, and even perhaps lower the tem-
perature of the body. It seems to me that this would be an "alter-
ative" medication of great power; but I will stop now, admitting
my incompetence in these difficult matters.
1 Here is the list of my notes on this subject, with the dates of their publications:
A. — Rechcrchcs experiment ales sur I'influcnce que les changements dans la pression baro-
metrique excrcent sur les phenomenes dc la vie. — Comptes-rendus de VAcadcmie des sciences.
Note 1. — Mort dans I'air confine; diminution de pression. (Session of July 17, 1871.)
Note 2.— Mo-rt dans I'air confine; augmentation de pression. (Session of August 21, 1871.)
Note 3. — Mort par I'acide carbonique; action toxique de Voxygene. (Session of February 26,
1872.)
Note 4. — Les modifications dans la pression barometriquc n'agissent qu'en modifiant la tension
de Voxygene. (Session of July 1, 1872.)
Note 5. — Les gas du sang sous diminution de pression. (Session of July S, 1872.)
Note 6. — La decompression brusque. (Session of August 19, 1872.)
Note 7. — Les gas du sang so-us augmentation de pression. (Session of August 26, 1S72.)
Note 8. — L'empoisonnement par Voxygene : dose, symptomes; analyse physiologique. (Ses-
sion of February 17, 1873.)
Note 9.— La decompression brusque : analyse, prophylaxie. (Session of March 3, 1873.)
Note 10. — Action toxique de I'acide carbonique. (Session of May 19, 1873.)
Note 11. — Action des variations de pression sur fa vegetation. (Session of June 16, 1873.)
Note 12.— Action toxique de Voxygene : ralentissement des oxidations. (Session of August
25, 1873.)
Note 13. — Experiences personnelles sur la depression. (Session of March 30, 1874.)
B. — De la quantite d'oxygene que pcut absorber le sang aux diverses pressions barometriques.
Proceedings of the session of March 22, 1875.
C — Influence de I'air comprime sur les fermentations. Proceedings of the session of June
28, 1875.
D. — De V emploi de V oxygene a haute tension commc procede d' investigation physiologique.
Proceedings of the session of May 21, 1877.
2 Journal offlcicl of May 22, 1875, p. 3624.
3 Journal officiel of June 14, 1S76. p. 4165.
4 Des accidents qu'on observe dans les hautes ascensions aerostatiques. Theses de Paris,
1875.
5 Encore un mot sur le mal des montagnes. Bull, de la Soc. med. de la Suisse romande,
1874, p. 261-264.
6 Experiences sur la temperature du corps humain dans facte de Vasccnsion sur les mon-
tagnes. Third series. Geneva and Bale, 1874. (Extract from the Bull, de la Soc. med. de la
Suisse romande.)
7 In a copper mine in the Duchy of Cornwall, the mine of Carn-Brea, P. Moyle found a
still lower proportion of oxygen (14.51). Two men were working in it; but he says nothing about
physiological disturbances. Ann. de phys. et de chimie, Third series. Vol. Ill, p. 318-331. 1841.
8 On the Temperature of the Human Body during Mountain. Climbing. Mature, Vol. XII,
p. 165, 1875.
9 Temperature of the Body in Mountain Climbing. Nature. Vol. XII, p. 186, 1875.
10 Ueber das Verhalten d'er Korpertemperatur bei Bcrgbcsteigungcn. Arch, dcr Hcilkunde.
XVI, p. 276-281, 1875.
11 Le mont Dore; Davos. Etude medicale et climatolosique. Paris, 1875.
12Camptes rendus de V Academic des sciences, Vol. LXXVIIT, p. 946 and 1060; 1874.
13 M. Croce-Spinelli here is mistaken in his reference. Gay-Lussac did not suffer from
hemorrhage at all. (See in Part I, page 180.)
14 La Nature, number of May 1, 1875: third year, first semester, p. 337-344.
15 Les inhalations d'oxygene et Vasccnsion du Zenith. Repertoire de pharmacie. April, 1S75.
10 L'Aeronaute, July, 1875.
17 This passage is a reply to the statement of M. Faye, that ascensions above 70OO meters
were of no practical importance to science. (Comptcs rendus de I'Acad. des sciences. Vol. I XXX.
p. 1037, 1875.)
i8 Obituary. The Geological Magasine, 1874, p. 383.
1008 Summary and Conclusions
19 Nachrichten uber die letsten Tage dcr vcrstorbencn D. F. Stoliczka. Verhandl. dcr K. K.
gcologischen Reichsanstaltj 1874, p. 279-285.
20 Recherche s d'anatomie, de physiologic et d'organogenic pour la determination des lois dc la
genese et de I evolution des especes animates. First memoir. Physiologic de la respiration chez
les oiseaux. Paris, 1875.
21 Contribution a V etude de la physiologic comparee du sang des vertebres ovipares. Comptcs
rendus de la Societe de biologie, Vol. XXVI, p. 278, 1874.
22 Influence de la pression de I'air sur la vie de I'hommc. 2 vol. Paris, 1875.
23 I take these figures from the diagram in Figure 87; supposing that the first descent took
place regularly, the stay between 500 meters and 70O0 meters would have lasted 45 minutes and
the stay above 7000 meters about an hour.
24 By reducing the apparatus to a single cylinder, which each traveller would carry, one could
have 230 liters of capacity at a pressure of 30 atmospheres, with a weight of 8 kilograms; by mass-
ing three cylinders, carried by a special guide serving several travellers, one would have a capacity
of 510 liters with a weight of 17 kilograms.
25 Recherches physiques sur la respiration de I'homme. Journal de Robin, Vol. I, pages
523-555, 18&4.
26 The analysis on the spot of the gases of the arterial blood of thoroughly acclimated ani-
mals or the wild animals of high regions (yaks, llamas, especially condors) cannot be made for a
long time. But, since the work of M. Jolyet (Comptcs rendus de la Societe de biologie, 1874) has
shown that the capacity of the blood to absorb oxygen does not change after putrefaction, noth-
ing would be easier than to collect the venous blood of a healthy and vigorous man (a.i acclimated
European or an Indian) or of an animal, defibrinate it, and send it in a well-corkeidl flask: it
would then be sufficient to shake it vigorously in the air to judge its capacity of absorption dur-
ing life. Fifty cubic centimeters are enough for each analysis.
27 In this reference see the judicious remarks of M. Gavarret: De la chale-ur produite dans
les etres vivants, Paris, 1855, p. 277. After 20 years, they are still applicable to present science.
28 Lavoisier had found, per kilogram and per hour, a production of 22.9 calories. Barral an
average of 23 calories, which would make, for 60 kilograms and 24 hours, 3300 calories. M. Beclanl
estimates 2500. (Traite elementaire de physiologie humaine, section 166.)
28 Peclet worked with this problem in its most general form. (See his Traite de la chalcur
consider^ dans ses applications. Third Edition, Vol. Ill, p. 418-453. Paris, 1861.) Two causes co-
operate in taking from the body under experiment the heat which must be restored to it: radia-
tion and contact with the air. Peclet has found that, within the limits of temperature with which
we are dealing, the amount of the cooling by radiation in an hour and for a square meter of sur-
face is expressed by the formula kt (1 + 0.0056t) and that of the loss of air in contact by k.'t
(1 + 0.0075O, t designating the excess of the initial temperature of the body over that of the
ambient medium. Now the coefficient k varies considerably according to the nature of the
radiating surface, since it amounts to 0.26 for polished yellow copper and 4.01 for soot: we cannot
guess what it is for human skin and for clothing.
On the other hand, the coefficient -k' depends on the form and size of the body; we can.
according to Peclet, by likening the human body to a cylinder 1.70 meters high and 0.12 meters
in diameter (surface 12,832 square centimeters) get from it the approximate formula.
0.0345 0.8758
k' = (0.726 4 ) (2.43 + ■ )
V 12 V 170
This amount too would be "only a somewhat inaccurate estimate."
We see that the elements necessary for solving the problem that we have set ourselves
are absolutely wanting. To determine the value of the coefficients k and k', we should resort to
direct experimentation, based on the principles indicated by Peclet. It could be done by covering
with human skin, freshly removed and kept moist, a hollow cylinder of metal, of about the form
and dimensions of the body, filling this cylinder with water at 38°, with an agitating system
and thermometers intended to stir the water thoroughly, and following then the decrease of the
temperature.
We would thus get the amount of heat necessary to maintain our temperature at its normal
degree during repose, in a vertical position and a state of nudity (let us note that we could
by this same method study the influence of different kinds of clothing). If the number obtained
was considerably less than 2500 calories, we would conclude that our hypothesis is probable.
30 To support the statement of M. Jourdanet about the real dangers of continued residence
in high altitudes, a subject which I am only skimming over, referring to his fine book for a com-
plete study, I shall quote the following assertion of Reissacher (Chemische Brief e, Vol. II, p. 48).
which I borrow from George von Liebig, p. 450 (Deutch. Archiv. f. Klin. Med. f., 1971) :
"According to statements of the managers of the mines of Bockstein, at the top of the
Goldberg, in the Rauris (2433 meters, pressure 56 centimeters), miners are unable to work after
the age of 40, and at Rathausberg, on the Bockstein (from 1996 meters, pressure 59 cm. to
2166 meters, pressure 58 cm.), they are past work at 50 ... . Dogs and cats cannot live on the
Goldberg: they succumb t.) paralysis of the extremities and respiratory disturbances."
31 Les derniers progres de la science— Paris, 1868. p. 108.
Chapter II
INCREASED PRESSURE
Subchapter I
OBSERVATIONS, THEORIES, AND RECENT
DISCUSSIONS
1. High Pressures.
The study of high barometric pressures has not been the subject
of any recent work. The results of my experiments on the action
of oxygen at high tension were accepted without dispute, I might
even say without criticism, by physiologists. Similarly, for the
effects of sudden decompression and their explanation demon-
strated by my researches, no new fact, either in industry or in
science, has been produced which can be reported here. I shall
except only a very interesting work of M. Guichard,1 an engineer
with great experience in the use of compressed air and personally
very skilled in the use of the diving-suit.
The article of M. Guichard is composed of two kinds of observa-
tions. The most numerous relate to the stay in poisonous gases
(CO, CO., C2H4, S02, etc.) ; these, in spite of their great practical
interest, and the dramatic details of one of them (Observation
VIII) , have no connection with the subject of our research. In the
others, it is a question of respiration in compressed air; I quote two,
interesting for various reasons:
Observation XIV. Seven divers were successively seized by
epistaxis under a pressure of a column of water of 9 meters. To show
the use of a new apparatus for artificial respiration, I descended into
a vast masonry basin containing very clear water at a depth of 9
meters. The ascent and descent were executed without any time pre-
1009
] 010 Summary and Conclusions
caution, considering the low maximum pressure to be undergone and
my practice in enduring it.
I next sent down with more precaution, successively, seven miners,
Sardinians by birth, who ordinarily worked at extracting lead ore.
Their constitutions were rather weak. They had been exposed for
several years to swamp fevers prevalent in the country all summer.
These men had a poor diet, eating vegetables and fruits almost ex-
clusively; they slept in the open air six months out of the year. They
were in general indolent and did a poor day's work.
These details will perhaps explain why they were all seized by
more or less abundant nosebleed after having endured four to five
minutes, some of them ten, an atmospheric pressure corresponding
to 9 meters of water, the total depth of the basin into which they
descended. The fact is that without exception they ascended with
blood issuing from the nose and in some of them, from the ears.
In general, symptoms of this sort appear only at great depths, 35
or 40 meters, especially when the decompression is too rapid.
Observation XVI. Beginning of asphyxia in a closed vessel under
three meters of water. I descended equipped with an apparatus into
a little circular basin 3 meters deep and 4 meters in diameter. The
water was very muddy, and in spite of the shallowness, vision was
almost completely obscured; it was impossible to distinguish any-
thing on the outside. Inexperienced helpers managed the air com-
pression apparatus.
I had lost my bearings during my first steps on the bottom of
the basin and the signal cord, which was not secured on the outside,
could not help me find the spot where the ladder was which would
have permitted me to return. And under these circumstances air
suddenly failed me. At least I could use only a reserve provided in
the receiver which enclosed me. The total capacity of this reserve
of pure air was about 30 liters. Taking on the average 12 inspira-
tions of 75 centiliters per minute, after three minutes I began to
breathe an air that had already been breathed. To escape immediate
asphyxia, at the beginning I took care to separate from the apparatus
the lead weights which held me on the bottom, so that I could rise
to the surface. I succeeded easily in detaching one of these weights,
but the second was still held by a cord when all effort became im-
possible to me. I was perspiring abundantly. I had a sensation of
intense heat in my head which diminished towards my lower limbs,
which seemed cold; my feet prickled.
I breathed very quickly and as if I had not been able to empty
my lungs by expiration. This peculiar impression of a conviction
that I could not expel the air in my lungs was very distinct. I note
it very particularly. Far from suffering from not being able to breathe,
I had a feeling that I could not exhale. The sensation appeared to
me about like what one would experience if one were buried up to
the neck and one's head were in a steam bath at high temperature.
My ears rang and luminous circles appeared before my eyes.
Air returned to me then, and the symptoms disappeared. I re-
covered in a few minutes, fastened on my weights, and staid ten min-
utes longer in the water so as not to ascend until I was quite normal.
Increased Pressure 1011
I got off with a rather violent headache, which had disappeared
the next day. I had stayed about three to four minutes in a closed
space containing 30 liters of air. I had a fast, full pulse for the two
hours following the experience. Salivation was difficult. I had a few
slight chills and stiffness. I slept well- at night.
In the historical part (p. 388) I reported with suitable discre-
tion an account of symptoms observed in the execution of impor-
tant projects by a large French company. I can speak more clearly
today, since the doctor of this company has published a very inter-
esting article on these data.1' It dealt with the construction of a
bridge over the Limfjord in Denmark; Doctor Heiberg, of Aalborg,
reports that the total pressure rose to 4.5' atmospheres; the work-
men remained from 2 to 5 hours in the work chamber.
The workmen, after having remained in the bell under compressed
air, and having descended into the chamber under this same pressure,
which at the end of the excavation reaches 3Vfc atmospheres, (in ad-
dition to the atmospheric pressure) all experience the same symptoms;
a loud buzzing in the ears, fatiguing respiration, while the pulse beats
more slowly, 60 to 70 per minute, a pressure on the eardrum which
generally disappears with the movements of swallowing, the nose be-
ing closed, a practice which the men always carry out to relieve
themselves. Except for the symptoms mentioned above, the men are
in good shape while they are working; danger therefore should not
be attributed to the pressure of the compressed air. Sometimes the
men are inconvenienced by different gases which rise from the bot-
tom of the fjord; once there even occurred an explosion of these
gases which burned three workmen severely; but, in general, the
stay in the compressed air causes no danger. On the other hand,
things are quite different when the men leave and the decompression
is carried on too quickly.
The remarkable symptoms of the illness which results are as fol-
lows: terrible pains in all parts of the body, accompanied by un-
endurable pricklings of the skin, great oppression at the heart, harder
beats, quicker pulse, 110-130, great heaviness in the head, drowsiness,
complete paralysis in the lower parts, the bladder and the rectum,
development of emphysemas in several parts of the body, generally
on the breast, under the armpits and on the arms, pain at pressure
on the spine in the lumbar region.
These symptoms generally appear as soon as the workmen have
come out, but sometimes after a delay of several hours. A workman
who had come out in good condition was suddenly stricken as he
reached home and died immediately.
In some workmen the symptoms disappear at the end of several
days; in others, the paralysis persists and often becomes incurable. I
have treated two men in whom the paralysis of the bladder and the
rectum grew better; sensitivity and motion returned, but the gait
remained uncertain. Both of them had to be sent home as unable
to continue working.
1012 Summary and Conclusions
Dr. Heiberg then gives interesting details of the autopsy of
two workmen whom he had seen die and of the symptoms appear-
ing in the patients he observed. I have already (p. 389) given a
very brief summary of the results of one of these autopsies, that of
Kiva, but here we are given more detailed information:
Kiva Ferdinando, thirty years old, was attacked, as he left the
work chamber, by pains in his limbs, with complete paralysis of the
bladder, the rectum, and the lower limbs; he half fainted, cyanosed,
his respiration is rattling, there are sounds of moist rale in the lungs,
the pulse is weak and rapid. He is taken to the hospital July 26,
1875; his condition does not change, the paralysis remains in the same
place, he is continually delirious, then the collapse comes and death
occurs July 30 during the night. In the autopsy the lungs are found
to be full of blood, with a secretion from the bronchial tubes mingled
with blood and a frothy lymph. The spinal cord was quite soft over
an extent of several inches in the lower dorsal and upper lumbar
region. The softening had very definite limits, without a trace of
blood, inflammation, or exudation. In the brain, heart, kidneys, and
spleen, nothing abnormal; but my attention was not yet directed to
the development of air in the veins, because at that time it was un-
known to me.
The other case, which also ended in death, could not be observed
while the patient was alive. The workman was returning home seem-
ing well. On the way he felt ill and fell dead as if struck by lightning.
The next day the autopsy was performed; the body was already stiff;
a deep cyanosis was observed on the body, particularly on the breast,
under the armpits, and on the left arm, where a very distinct
emphysematous condition could be felt; when an incision was made at
these places there issued a bloody lymph with a considerable mix-
ture of air; the spleen, which was very emphysematous, crackled all
over its surface at pressure, and when an incision was made, there
issued blood mixed with a great deal of air; no air bubbles in the
aorta, the jugular vein, the iliac and crural arteries. The kidneys and
the liver are in normal condition, the urinary bladder empty, a de-
velopment of air in the epiploon, the brain not full of blood, very dis-
tinct and large bubbles of air in the basilar artery, in the sinus, and
in the veins of the upper surface of the brain; among these air
bubbles, very small, almost liquid spots of blood. The stomach was
much lengthened and contained a certain quantity of vegetable food.
No investigation of the spinal cord was made because careful ex-
amination of the veins required much time for making the liga-
tures.
Although these two autopsies are very imperfect, and leave much
to be desired, it seems to me that they agree completely. In the first
case, in which the symptoms of the disease had developed for several
days, and in which bubbles had met and concentrated in the spinal
cord, a complete softening occurred entirely in agreement with the
experiments of P. Bert. In the second case, in which death was in-
stantaneous before the bubbles had advanced so far, there were
Increased Pressure 1013
bubbles of air in the veins of the brain, with emphysemas in several
places, both in the interior and on the exterior, and quite agreeing
with what P. Bert had observed and reported as being the physiologi-
cal effect of passing from a high pressure to the atmospheric pressure.
The last autopsy seems also to show that three quarters of an hour
is too short a time to avoid dangers, when the pressure is 3Vfe atmos-
pheres. However it is not impossible that the hearty meal of vege-
tables which was in the stomach had something to do with the acci-
dent.
I treated in the hospital fourteen patients, one of whom died
and two were sent home as incapable of resuming work. Eleven
cases were less severe; they were cured after several days; in all, the
characteristic symptoms were observed in a greater or less degree,
particularly severe pains in the limbs, cardiac pressure, painful respira-
tion, cyanosis, pain on pressure along the vertebral column ill the
lumbo-dorsal region, dragging gait, difficulty in urination; in two cases,
complete paralysis of the bladder, rectum, and lower parts, with
asthenia. I did not notice the development of emphysemas under the
skin; but the workmen state that they exist. I was present at the
moment when the workmen left the bell, and I did not observe this
symptom; but I should add that none of the workmen whom I ex-
amined in this way fell ill.
Since the two cases in which the paralysis improved, but the
conditions of the patients remained such that they could not resume
their work and had to be sent home, one to Prague and the other
to Milan, were very similar, I shall describe one.
Eger Mayer Francois, 34 years old, strongly built, was taken to
the hospital July 23, 1875; he had fallen ill immediately after his
exit from the bell; ordinary pains, complete paralysis in the lower
parts, bladder and rectum, much pain on pressure on the lumbo-
dorsal regions. Cupping-glasses, induced electric currents, lukewarm
baths, and shower-baths were used. After August 1, he could urinate,
the paralysis of the rectum continued, there was a little catarrh of
the bladder, but the urine was normal. August 18, he could stand
erect and walk with crutches, and then with two sticks. His condition
improved perceptibly, he took steam baths, nux vomica, and con-
tinued the electricity; at last the paralysis of the rectum improved
also; he took longer walks, but his gait remained unsteady. Novem-
ber 2, he was sent to Prague, and recently I learned that he had died
after quite a long stay in the hospital.
The condition of the second patient was almost the1 same, only
the paralysis of the bladder lasted longer; after a stay of several
months in the hospital he could take long walks. But as he could
not resume work he had to be sent back to Milan.
The Company of Fives-Lille, which was carrying out this work,
having consulted me in regard to these disturbing symptoms, I
gave advice as follows: (1) to make the decompression still slower;
(2) to set up heating apparatus to spare the workmen the unen-
durable pains and dangers of a chill in the decompression chamber.
1014 Summary and Conclusions
I had the satisfaction of receiving the following note shortly after
from one of the executives of the company:
We have transmitted to our Aalbert Works the information you
gave us about the precautions to be taken for men working at high
pressures.
We have exceeded the depth of 32 meters below the level of the
water, and the symptoms disappeared when the time in the exit lock
was increased.
2. Low Pressures. Medical Apparatuses.
The effect of low pressures has given rise to only a small number
of articles in recent years. But two of them are of considerable
importance from the theoretical point of view.
M. J. Pravaz, August 9, 1875, sustained a thesis before the
Faculty of Science of Lyons on the effects of an increase of atmos-
pheric pressure, in which he considers successively the circulation,
the respiration, and the nutrition.
In regard to the first of these functions he notes, like all former
observers, a certain slowing of the pulse during a stay in compressed
air, and he explains it: (1) by the increase in the temperature of
the body, acting secondarily upon the heart; (2) by the increase of
the arterial tension. The latter is supposed to be caused by the
direct obstacle to the course of the blood occasioned by the com-
pressed air acting to "drive back from the peripheral parts the blood
of the capillaries and veins (p. 23) ." We see that M. Pravaz accepts
the theory of superficial crushing in compressed air; he considers
as proof the strange experience of Vivenot which we reported
above and rated at its true value. We do not think it worth while
to repeat the refutation of these errors.
The respiration, he says, becomes both less frequent and more
ample, at least in the neighborhood of a half-atmosphere of com-
pression; beyond (M. Pravaz goes only to two atmospheres), there
is a movement in the opposite direction. The explanation of these
data is the one which Ch. Pravaz (p. 447) had already given, whose
opinions his son adopts on all points. The variations in the ampli-
tude have been measured by the aid of the anapnograph of MM.
Bergeon and Kastus: if the extent of respiratory movement at
normal pressure is expressed by 100, it becomes 106 at a pressure of
19 cm., 118 at 38 cm., 109 at 76 cm. But M. Pravaz did not seek to
study the relation between the frequency and the amplitude, so as
to determine the variations in the output, in the pulmonary ventila-
Increased Pressure 1015
tion, or, in other words, in the quantity of air which passes through
the lungs in a given time.
The most original part of the thesis is that which relates to the
study of the variations in the production of urea. M. Pravaz has
made five experiments on this subject:
In the first, he measures the urea voided during 24 hours first
at normal pressure, then under increased pressures from 10 cm. to
76 cm.: the urea decreased (average: from 29.6450 gm. to 28.4448
gm.).
The second was performed in the same way, with the added pre-
caution of submitting to a fixed and regular diet: increase of urea
(average: from 29.1685 gm. to 31.4947 gm.).
The third, like the second in method, gave a decrease (average:
from 27.2401 gm. to 26.2224 gm.) .
In the fourth, the method was changed. The diet was the same
(this diet, which seems to me very low in carbon and a little ex-
aggerated in nitrogen, was composed of 250 gm. of bread, 200 gm. of
lean meat, 100 gm. of dry cheese) , but the urine was collected only
in the morning, fasting, for three hours, either in open air, or under
pressure. Here, an increase in compressed air (average: from
3.2019 gm. to 3.4965 gm.) .
Finally, in the fifth, performed like the preceding one, the ex-
cretion of urea was studied from hour to hour during the stay in
compressed air; the averages are: in open air 0.9492 gm.; during
the first hour of compression 1.0758 gm.; during the second 1.0651
gm.; during the third 1.0363 gm.; in the following hour, at normal
pressure 0.7178 gm. ■ •
M. Pravaz concludes from these data:
1). That the excretion of urea increases under the influence of
compressed air;
2) . That this increase is at its maximum at the beginning of the
compression;
3) . That it is greater at low pressures (at about 20 cm.) than at
high pressures (from 30 cm. to 76 cm.).
4) . That after the decompression there is a decrease in the pro-
duction of urea.
The experiments on the exhalation of carbonic acid, relating
only to the percentage of this gas in the expired air, and not to the
quantity given off in a given time, could give no really interesting
result.
Finally, M. Pravaz thinks he can conclude from his observations
on the temperature, that it follows exactly the same course as the
1016 Summary and Conclusions
production of urea: the greatest deviations are, in the rectum, of
0.34°.
I refer to the original article for the reading of the explanations
which M. Pravaz gives of the variations in the nutritive phenomena
which he thinks he has observed. Personally, I consider that a
single experiment does not permit one to draw conclusions, and
that one should suspend judgment on the question of whether the
combustions really increase only during the first moments of the
stay in compressed air. As for the observations which embrace the
24 hour period, the first should be eliminated, since the diet was
not regulated. For the two following, no precautions were taken
in regard to muscular work: "exercise," says M. Pravaz himself,
"was necessarily variable from one day to another, and gave rise to
changes in the production of urea, which might introduce into the
problem an undeterminable unknown" (p. 43) ; one should there-
fore take no account of it. Finally, the fourth presents irregular-
ities which seem to take away all value from the averages he
strikes; during three hours fasting, the quantities of urea obtained
were:
First day Normal pressure 3.0075 gm.
Second day 10 cm. compression 3.1933 gm.
Third day 19 cm. compression 3.6990 gm.
Fourth day__ ___ 38 cm. compression __ 3.5685 gm.
Fifth day 57 cm. compression 3.2711 gm.
Sixth day 76 cm. compression 3.7507 gm.
Seventh day Normal pressure 3.3963 gm.
We see, besides, that the maximum of production coincided
with the highest pressure, which does not agree with the opinion
of the author.
Without dwelling any longer on this critical analysis, I quote
the general conclusion of M. Pravaz:
If we examine from a general point of view the effects of increase
of atmospheric pressure on the animal economy, we are led to dis-
tinguish in the action which compressed air exerts two elements: the
pressure element and the superoxygenation element.
From the pressure or mechanical element rise principally the
modifications produced in the rhythm and amplitude of the respi-
ration.
The modifications experienced by the circulation and the nutrition
are the result of the conflict carried on between the super oxygenation
element and the pressure element, the first tending, by the super-
activity it gives to the chemical phenomena going on in the tissues, to
increase the production of urea and carbonic acid, from which come
Increased Pressure 1017
the rise in temperature and consecutively the speeding up of the heart
beats noticed the first instants of a stay in a denser atmosphere; the
second tending, on the contrary, by the modifications it causes in the
physical conditions of the flow of the blood and by the increase of the
arterial tension resulting, to play a role of moderator by lessening,
through the consecutive slowing down of the circulation, the speed
of the organic combustions and the production of heat by reason of
the stay in compressed air and the rise in pressure. (P. 65.)
Georges Liebig, whose works we have already analyzed (p. 437
and 481) , recently published an important memoir,1 in which he
gave as his special purpose the study of the excretion of carbonic
acid at normal pressure (on the average 720 mm.) and in com-
pressed air (on the average 1040 mm.). The person on whom the
experiment was carried on was a man 39 years old, weighing 59
kilos, with a lung capacity of 3.9 liters; his mode of life was very
regular, and the author gives its details (p. 504) ; the experiments
were always carried on at the same hour. The patient, seated,
with a sort of mask over his mouth and nose, breathed for 15
minutes a quantity of air measured by a gas meter; the apparatus
used, the description of which we cannot give here, is that of
Professor Jolly.4 Analyses gave at the same time the volume of
air which had passed through the lungs during the length of the
experiment (15 minutes), the quantity of carbonic acid produced,
the quantity of oxygen which remained in the expired air, from
which one derived the quantity of oxygen absorbed, the nitrogen
being considered invariable.
I reproduce the summarizing table (Table XXII) of his 37
experiments.
It is upon this important series of analyses that G. Liebig bases
a discussion which is not always very clear, and whose principal
points we shall try to select.
In the first place, he arranges his experiments in several series,
which permits him to compare several averages; these series are
established according to the figures in Column 4, that is, according
to the quantity of air which has circulated in the lungs for fifteen
minutes. At normal pressure, for instance, the first series includes
the experiments in which the pulmonary circulation varied from
121 to 130 liters. The numbers of Column 2 of Table XXIII indi-
cate the limits for each of the series; in the other columns are
listed the averages which correspond to them.
If we consider first the chemical side of the question, we see
that in the general average (Table XXII), as in each individual
average of the series of equal rank (Table XXIII), the consump-
1018
Summary and Conclusions
Table XXII
3 4
Dates of
01
c
3
o
1 £
o <>> £
experiments
2$
°.2s
£a£
c.s«
to «-'
<s£
3a)£
3 b ~
>o«
3 «_,
30,
«Ph
2tf Q.
orS-S
< £
tfo.S
C?U.S
liters
liters 1
grams
grams
I
[ A. Normal Pressure
November 15
720mm.
15.3
116.5
0.51
7.171
6.750
15.7
117.9
0.50
6.465
6.630
November 16
719
15.5
129.2
0.56
8.019
7.719
17.5
128.0
0.48
7.305
7.647
14.6
115.2
0.53
6.380
7.093
November 17
722
17.1
123.8
0.48
7.945
8.132
15.5
118.1
0.51
8.078
6.373
16.0
120.2
0.50
7.187
8.012
November 18
719
17.0
127.5
0.50
8.345
8.710
15.0
114.8
0.51
7.033
8.119
19.6
129.6
0.44
7.972
7.476
November 28
720
18.2
118.6
0.43
6.935
6.887
1
| 17.0
109.1
0.43
5.792
6.014
I 18.2
108.4
0.40
5.675
5.747
May 17
710
15.7
112.4
0.48
6.657
6.782
15.5
103.2
0.44
5.112
6.030
May 23
723
17.5
117.9
0.45
7.327
7.097
Average
1 719
| 16.5
| B. Inc
118
reased Pr
0.48
essure
7.058
7.132
November 22
1039
\ 15.0
113.4
0.50
7.833
7.330
| 15.6
111.5
0.47
7.387
6.479
15.6
106.4
0.45
6.563
5.824
November 23
1039
16.4
114.5
0.46
8.273
7.246
1 15.4
107.8
0.47
6.481
6.322
1
| 16.2
111.0
0.46
7.374
6.602
November 25
1040
| 15.8
107.2
0.47
7.719
6.535
| 16.5
102.9
0.42
7.298
7.691
| 16.2
105.8
0.44
7.107
7.244
November 26
1040
[ 15.2
104.6
0.46
6.854
6.424
| 15.9
107.4
0.45
6.783 ■
7.551
[ 16.2
107.6
0.44
7.494
8.192
May 20
1038
| 15.3
115.6
0.50
8.814
8.737
15.5
112.1
0.48
7.869
8.082
May 21
1043
| 16.5
118.5
0.48
8.879
8.455
16.1
115.1
0.48
7.804
8.013
16.1
115.2
0.48
7.546
7.358
May 22
1042
15.6
104.0
0.44
7.185
6.297
| 15.7
109.4
0.46
7.413
6.722
1
15.6
105.9
0.45
6.954
6.842
Average
| 1040 |
| 15.9
110.0
0.46
7.481
7.197
tion of oxygen (Column 6) appeared greater in compressed air
than under normal pressure. The general average gives 7.058 gm.
under normal pressure, and 7.481 gm. in compressed air, with
extreme deviations going, in the first case, from 5.112 gm. to 8.345
Increased Pressure
1019
gm., and in the second case, from 6.481 gm. to 8.879 gm. The dif-
ference is much smaller and less constant for carbonic acid
(Column 7), if one considers only the averages; however, the
examination of the maxima and minima corroborates the idea of a
greater formation of carbonic acid in compressed air: at ordi-
nary pressure, indeed, the variations were from 5.747 gm. to 8.710
gm., and under pressure from 5.824 gm. to 8.737 gm.
Table XXIII.
3 4
Limits of
Series
■g||
<u
o"S3
c
3
O
73
-h-ci.3
HI
OJ
^ * c
<U !°'3
&'Hg
<u -,"43
^og
ga
|%
m f £
g«2
(0 8>"
3,
fctfA
QTaB
tea
o-d'.S
£8.s
| inspired liters
liters
A. Normal Pre
liters
ssure
grams
grams
I
I from 121 to 130
17.3 1 127.6
0.49
7.91
7.94
II
from 112 to 121
15.7 1 117.3
0.49
7.12
7.13
III
from 103 to 112
16.8 1 108.8
B. Increased F
0.44
ressure
6.11
6.33
I
from 113 to 118
16.1 1 115.8
1 0.48
8.26
7.96
II
from 108 to 113
15.6 1 111.5
1 0.47
7.56
7.04
III
from 103 to 108
15.8 | 106.0
0.44
7.04
6.89
The numbers relating to pulmonary ventilation (Column 4) are
also very interesting. First, evidently, there passes through the
lungs, in a given time, less air, in volume, under increased pressure
than at normal pressure; the general average gives 110 and 118,
with deviations, in the first case, from 102.9 to 118.5, and in the
second, from 103.2 to 129.6. The number of respiratory movements
is also decreased in compressed air; on the average it falls from
16.5 to 15.9 per minute. It results from these two modifications
that the respiratory amplitude hardly changes, since it varies on
the average only from 0.48 liters (normal pressure) to 0.46 liters
(compressed air). Let us add that an attentive inspection of the
respiratory movements, holding a watch with a second-hand, would
have permitted G. Liebig to note that the respiratory rhythm itself
changes in compressed air, the inspiration becoming shorter and
the expiration longer: the ratio of duration between these two
phases in one of his observations would have passed from 2 : 3
to 1 : 2. He therefore agrees with what Vivenot had said (See
Figure 9), and contradicts Panum.
1020 Summary and Conclusions
All these results, which are in harmony with the data already
known, are explained, according to G. Liebig, by the mechanical
action of the increased pressure:
The mechanical effects of pressure can be explained by the fol-
lowing comparison. Let us suppose a flask covered by an elastic
membrane; if one extracts the air from this flask by means of a tube
penetrating the interior, he will observe that the membrane is bent
inward. The greater the outer pressure, the deeper will be the
depression (in the membrane), and vice versa, since its own elas-
ticity acts in a direction opposite to that of the air pressure.
During the inspiration, when the walls of the chest expand, and
the diaphragm contracts, a vacuum tends to form around the lungs,
and the greater the outer pressure of the air in relation to the elas-
ticity of the lungs, the more easily will this vacuum be filled. The
expiration will become more difficult, because the outer pressure of
the air offers resistance to the contraction of the lungs.
Panum and Vivenot have shown that the walls of the chest and
the diaphragm take in compressed air a state of equilibrium different
from the ordinary state, with an enlargement of the thorax. These
walls then present a tension from within outwards which opposes the
inverse tension of the lungs; both of the two forces are in a deter-
mined equilibrium with the third active force, namely, the pressure of
the air. If this force is increased or diminished, a change in the
equilibrium of the system will be produced. (Page 516.)
Dr. Leonid Simonony director of the aerotherapeutic establish-
ment of St. Petersburg, very recently published an important book
on barometric compression, from the medical point of view. The
physiological part contains a very interesting summary of previous
knowledge, and also an account of a certain number of personal
experiences on the variations of weight in patients subjected to
aerotherapeutic treatment.
In the course of the year 1873, Dr. Katschenowsky made observa-
tions in my medical service on himself and other persons .... The
result is as follows: With quantities of food such that in ordinary air
there would be an equilibrium between the ingesta and the excreta,
the weight of the body diminishes successively under the influence
of a daily sojourn of two hours in compressed air. (Page 79.)
But, M. Simonoff observes, the appetite constantly increases; now
if one satisfies it, instead of regulating the diet as Katschenowsky
did, the weight of the body increases. Out of 53 persons whom he
examined, 32 weighed more after the treatment (on the average,
1077 gm. per individual) ; two had not changed; 19 had lost weight
(an average of 786 gm. each) (pages 81-92) . We must note that all
these subjects were invalids, and that the increase of the weight of
the body and the appetite seemed to be only an indirect effect of
Increased Pressure 1021
the improvement due to treatments. For real proof, one would
have to experiment on individuals in good health.
Subchapter II
SUMMARY AND PRACTICAL APPLICATIONS
1. High Pressures.
The discovery of the toxic action of oxygen at high tension cer-
tainly constitutes the most interesting and most unexpected part of
this long work. Experiments made on animals and plants, on
beings dwelling in the air, as well as those dwelling in the water,
on beings of complicated structure, as well as on microscopic
monocellular animalculae, and on anatomical elements separated
from the body, have shown in the clearest way that above a certain
oxygen tension of the ambient atmosphere life becomes impos-
sible, and that death may come with remarkable rapidity.
In warm-blooded animals, the violent convulsive phenomena
which we have described (p. 741) appear at once above 20 at-
mospheres of air; very speedy death takes place above 25 atmos-
pheres; but painful effects are clearly felt at 6 atmospheres, as we
have seen by an indirect method (p. 713) .
We have given abundant proof that they are the consequence
not of the barometric pressure as a physico-mechanical agent, but
of the increase in the tension of the ambient oxygen. I refer you
for all these data to Chapter IV, subchapter I, where they were
studied in detail. I have given there not only the description of
the symptoms of poisoning by oxygen, specifications of the lethal
dose of exterior oxygen, expressed in tensions, but also that of the
oxygen content of the blood which corresponds to the different
stages of the exterior phenomena: death occurs quickly when the
proportion of this gas has increased by a third in the arterial blood.
I also showed there the apparently paradoxical result that under
the influence of greater oxygenation of the blood, the tissues oxidize
less, the organic combustions lose energy, the production of car-
bonic acid, the excretion of urea, the intra-sanguine metabolism
of sugar are impeded, and that consequently the temperature drops.
These data cease to seem odd when linked with those given in
Chapter VI. All the anatomical elements, it is shown there, undergo
the formidable effects of compressed oxygen (p. 839) ; the micro-
scopic organisms which cause true fermentations, are killed by
1022 Summary and Conclusions
this agent;0 putrefaction is stopped," and the consumption of oxygen
which accompanies it lessens so much that it can be reduced to
zero. Now the anatomical elements, in the presence of excessive
oxygen, behave like free elementary beings, and when they die,
cease to consume the oxygen necessary for the maintenance of
their vital acts.
Let us follow this a little further. And first, we have seen for
plants as for animals that the pressure of 5 or 6 atmospheres of
air (oxygen tension 100 to 120) brings symptoms serious enough
for laboratory experiments, which are carried on in a short space
of time, to indicate them very clearly. So respiration of pure
oxygen at normal pressure (tension 100) cannot be long endured
by warm-blooded animals. At about 10 or 12 atmospheres symp-
toms appear that are quickly fatal, and at about 20 atmospheres,
the characteristic convulsions of oxygen poisoning. Now at 6
atmospheres the oxygen of the arterial blood has increased by
only 3 volumes; at 12 atmospheres, it has passed on the average
from 20 to 25 volumes; at 20 atmospheres, from 20 to 29 (See Fig.
36) ; when it passes from 20 to 35 (example: Experiment
CCLXXXVII, 27 atmospheres) death occurs in a few minutes. On
the other hand, we have several times stressed this fact, that the
arterial blood, in the normal acts of respiration, is almost never
saturated with oxygen. When the trachea is opened and there
follows, as often happens, a much exaggerated respiration, or when
blood is agitated in a flask of air, it gains 3 or 4 volumes on the
average.
So the pressure of about 6 atmospheres of air results in intro-
ducing into the arterial blood almost the quantity of oxygen which
would be necessary to saturate it under normal pressure. And, we
have seen, this pressure begins to be harmful to higher organisms.
The saturation of the blood would, then, be a harmful condition, and
by a happy arrangement, when it is reached, the apnea which
ensues prevents it at once from persisting.
From this degree of pressure on, the hemoglobin is saturated
with oxygen, and the oxygen which is added to the blood follow-
ing a progression which approaches Dalton's Law, is only dissolved
oxygen, equally divided between the corpuscles and the plasma;
and it even dissolves also in the tissues to the same degree, if the
stay in compressed air lasts a sufficient time. Now it is a fact of
the highest interest that in the presence of this free oxygen that
is simply dissolved, the inner oxidations slow up, then stop. It
seems that for oxidation the tissues need borrowed oxygen, taken
Increased Pressure 1023
from the oxy-hemoglobin, so that in the presence of dissolved
oxygen brought by compression, either the tissues become unable
to carry out this dissociation, or the corpuscles can no longer give
up their oxygen, and remain condemned to perpetual saturation.
I know nothing in physiological chemistry more curious than this
effect of the presence of dissolved oxygen, having as its result not
the activation but the checking of a combination. Whatever are
the possible explanations, it is certain that the organic oxidations
no longer take place when the blood corpuscle, laden nevertheless
with the maximum of oxygen, is surrounded by this sort of at-
mosphere of free oxygen, dissolved in the plasma, dissolved in the
tissues.
We have seen, I remind you again, that this cessation of the
oxidizing activity of the tissues takes place in the presence of an
excess of oxygen, not only in red-blooded animals, but in all living
beings. Now this cessation of vital phenomena is not merely
momentary, like that caused in lower beings by the diminution
of pressure, but is a real death, a definite death; which shows that
very evidently we have to do here not with a simple suspension but
with a deviation of the vital phenomena. A seed kept in a vacuum
germinates when oxygen is admitted; a dog with the convulsions
of asphyxia is restored when given air. But the seed kept under
compression will no longer germinate; the dog brought from com-
pressed oxygen to normal pressure may, after twenty-four hours
of continuous convulsions, die without having improved. (Experi-
ment CCLXXVIII.) It seems that under the influence of com-
pressed oxygen there is formed in the anatomical elements some
toxic product which cannot always be eliminated, and then kills
even when its cause has disappeared. To go further than this
hypothesis would seem to be imprudent in the present state of
knowledge.
The researches of M. Pasteur have shown that microscopic liv-
ing beings can be divided into groups, one needing for life contact
with the air, free oxygen (aerobic) , the other (anaerobic) fearing
air, on the contrary, and borrowing the oxygen which they consume
from organic materials which they separate for this purpose. Now
what we have just said shows that anatomical elements grouped in
tissues are essentially anaerobic. In the upper animals, where it
has been possible to carry the analysis of phenomena to great
lengths, we know that they secure their oxygen from the oxy-
hemoglobin; but when the latter is saturated, the oxygen appears
simply dissolved in the plasma and the tissues, the animals become
1024 Summary and Conclusions
ill and die if the experiment lasts long enough, or if the amount of
free oxygen is large enough, exactly as do the vibrios of the butyric
fermentation7 in the presence of atmospheric air. The red cor-
puscle alone seems an exception, for it appears quite essentially
aerobic; but I am inclined to think that that is only an illusion, for
this corpuscle itself, when its constituent stroma, its globuline,
contains free oxygen after the saturation of its oxygen-loving pig-
ment (hematocrystalline) , dies like the other anatomical elements
(p. 842). So, in the regular state of things, as we have seen, the
hemoglobin is never saturated with oxygen. We must note, fur-
thermore, that the aerobic micro-organisms, like the bacteria, also
die under the influence of compressed oxygen; we can then form
the hypothesis that they have in them, like the red corpuscle, some
material eager for oxygen whose oxygenated combination feeds
their own constituent substance. In this hypothesis, all living
beings and all their parts taken separately would be anaerobic.
At any rate, the parallelism is perfectly established between the red
corpuscles and the bacteria on one hand and the anatomical ele-
ments and the vibrios on the other. But however different they
appear to be, divided here two by two, they are all alike in the
death which strikes them rapidly in the presence of a sufficient
amount of dissolved oxygen.
Before leaving this subject, let us call attention once more to
this new application of the general rule, that when a poison strikes
the whole organism, it is the nervous system which reacts first.
The dog in compressed air first has convulsions; and these, disturb-
ing the mechanisms whose harmony is necessary for the main-
tenance of life, kill him before the other anatomical elements are
fatally attacked; but for the latter it is only a question of time. His
blood is still capable of recalling to life another bloodless dog;
but if it is agitated for some hours under oxygen pressure, it will
kill the healthy animal into which it is injected, far from being
able to save the dying bloodless dog. In the same way, the tail of
a rat which has been killed by oxygen can be grafted perfectly;
but a longer exposure to compressed oxygen will kill its elements
and the graft will be absorbed without suppuration.
2. Low Pressures.
Under this title, as I did in Subchapter II of Chapter IV, I in-
clude pressures between one and five atmospheres of air, in which
the oxygen tension varies between that of air (20.9) and the 100
of pure oxygen. With these tensions, as I have just remarked,
Increased Pressure 1025
the arterial blood is not completely saturated with oxygen,
although its oxygen content is greater and greater in proportion as
we rise above normal pressure.
It is very important for the doctor and the hygienist to study
these low pressures, because they are the ones used in therapeutics
on the one hand, and in industry on the other. But from my point
of view, what seemed most interesting was to find out at what
pressure the maximum of intra-organic oxidation took place. We
have seen, on the one hand, that from the lowest pressures up to
one atmosphere, and on the other hand, beginning with five or six
atmospheres and above, these oxidations continue to lessen: where
would be the top of the curve which represented these phenomena?
Now my direct analysis of the quantity of carbonic acid ex-
haled, of oxygen absorbed, and of urea secreted in a given time,
and my indirect researches on the rapidity of putrefactions tend
to show that it is in the neighborhood of three atmospheres, about
the oxygen tension of 60 that the maximum we are seeking is found.
The recent experiments of G. Liebig give the same evidence.
But I am the first to recognize that nothing is more difficult
than such experiments, and that conclusions are always dangerous.
In regard to the production of urea, for example, either we must
keep the subject on a very regular diet, and then the excess of
oxidation, if there is one, working on the materials of the organism
itself, will cease to appear upon exhausting them; or we must
increase the amount of food, and then the increase of urea pro-
duced will no longer have any possible measure, because we do
not know the equivalent in urea of the different foods: upon this
last point I have begun researches which are still incomplete.
But in spite of all these causes of error, I am struck by the agree-
ment of the analyses of Vivenot, Panum, G. Liebig, and J. Pravaz
with mine, and also by the unanimous testimony of doctors and
engineers on the increase of the appetite of patients or workmen
subjected to compressed air. My conclusions then seem to me at
least very probable.
It would follow, if we consider the higher animals, that organic
oxidations will increase in intensity as we approach the saturation
of the hemoglobin. We can imagine that the maximum point will
be where the oxidation takes place most easily, where the last
molecules of oxygen are hesitant, so to speak, hardly retained by
the hemoglobin, ready to leave it to combine with the tissues;
beyond this point, as we saw above, the oxidations lessen.
But on the other hand, the behavior and the speed of develop-
1026 Summary and Conclusions
ment of the lower animals, frog tadpoles, the larvae of insects, kept
for a long time under tensions of compressed oxygen between 21
and 100, show very clearly that even if there is an increase in
nutritive processes, there is no better general condition; far from
it. Beginning even with 80, the fatal effect of the oxygen is evi-
dently felt. The same thing is even more true for germinations,
which never take place better than under normal pressure.
When I had studied this point, I could not help being interested
in the modifications caused by compressed air in circulation and
respiration, modifications so often analyzed by doctors. Following
many other observers, I noted the decrease in the number of pulsa-
tions and the increase in the maximum pulmonary capacity: I
found that the quantity of air (in volume) which passes through
the lungs during a given time does not change noticeably in com-
pressed air: this point had not been directly investigated before
me; I should say that, according to G. Liebig, it would decrease
a little (in the ratio of 118 to 100).
The most interesting fact which this part of my researches fur-
nished me is the proof that the greater capacity of the lungs is
due to the mechanical action of the compression upon the intes-
tinal gases (p. 768) . It has another result of lessening the varia-
tions of the intrathoracic air pressure during the acts of inspira-
tion and expiration. Finally, I was the first to measure directly
the arterial pressure under compression, and to show that it is
considerably increased by the mechanical action of the pressure.
Up to now I have been rather severe against the explanations
which emphasized the mechanical side of the pressure and have
dwelt upon these new observations. But, as I have often said,
from this point of view, the pressure can act only on the gaseous
reservoirs; it does so for the intestine, which is like a closed bladder,
whose volume diminishes following Mariotte's Law, the lung hav-
ing to follow the diaphragm which drops more; it does so for the
thorax, which would be crushed if the tracheal opening did not
exist, and which would not be affected at all if this opening were,
as it is not, sufficiently wide.
But the relative intensity of this action of the pressure continues
to diminish with the amount of the compression; and that is easily
understood, for if the intestine loses, in passing from one to two
atmospheres, half of its volume, it diminishes only a fourth more
in passing from two to four. Furthermore, the increase of the
thoracic capacity can represent only a part of the reduction of the
volume of the intestine, because the walls of the abdomen fill up
Increased Pressure 1027-
a proportion which must increase with the pressure, since the
diaphragm in its descent meets stronger and stronger obstacles.
3. Sudden Decompression.
I think I explained in Chapter VII all that relates to this ques-
tion, which is relatively simple enough, because it is purely of
physical nature. I have shown that all the symptoms, from the
slightest to those which bring on sudden death, are the consequence
of the liberation of bubbles of nitrogen in the blood and even in
the tissues when the compression has lasted long enough.
These few lines are enough to summarize this part of our study,
to which we shall return in the following section.
4. Practical Applications. Therapeutics and Hygiene.
A. Therapeutics. I shall refrain, observing in this instance the
same prudence as when it was a question of rarefied air, from ex-
plaining and judging the applications made since the time of Junod,
Pravaz, and Tabarie of slightly compressed air in the treatment
of different diseases. However I can affirm, along with so many
others, the utility of this treatment in certain forms of asthma and
in anemia. But I prefer, after having mentioned these two diseases,
to say that the stay in apparatuses for compressed air seems to me
to act upon them in a different way: for asthma, I think it is the
mechanical action of which I have already spoken which is of
benefit; for anemia, I think that it is the chemical action, the more
perfect saturation of the hemoglobin.
The interest of this distinction lies in the fact that in cases
where chemical action should be sought, and they are very prob-
ably those in which it will be a matter of changing the nutritive
processes, the stay in the compression cylinders can be satisfactorily
replaced by the respiration of superoxygenated air: a great advan-
tage, you will understand, in therapeutic practice, for the costly
apparatuses for compressed air can never be operated outside large
cities and watering-places, whereas nothing is easier than to pro-
cure oxygen at home.
But one must be skilful in the use of oxygen inhalations. Since
the day when Priestley disputed with two mice "the honor of
having been the first to breathe dephlogisticated air"s up to the
present epoch, many attempts have been made to introduce respira-
tions of oxygen into the realm of therapeutics.1' The enthusiasm of
the authors at the end of the last century and the beginning of this
one for the curative virtue of the vital air, was tempered by only
1028 Summary and Conclusions
one fear: the irritating action of oxygen on the tissue of the lungs,
and especially the ravenous activity it would give to vital oxida-
tions. Brize-Fradin10 expresses himself warmly on this point:
Vital air or pure oxygen would soon wear life out instead of
maintaining it ... . The torch of life, burning fiercely, would soon
be extinguished .... Fever would soon carry off anyone who used
vital air immoderately.
It is impossible to breathe oxygen alone for more than two min-
utes; the pulse beats are then quicker, more frequent; a sensation of
unendurable discomfort is felt. (P. 133).
It is hardly necessary to say that the violence of the sensations
and of the symptoms experienced is purely imaginary, unless the
oxygen was badly prepared.
After having been completely forgotten, oxygen has been gain-
ing favor for several years. But I think that its application has
been bad, and that, if it is possible to hope for any advantage from
its use, the method must be entirely changed.
As a matter of fact, patients are given almost pure oxygen to
breathe, and since it is not possible to have a great quantity of
it, a few liters are administered (generally 30 as a maximum in
France), which are absorbed in 5 or 6 minutes at the most. This
mode of procedure has two disadvantages: first, one cannot hope
for any lasting action from a slight increase in the oxygen of the
blood for ten minutes at the most; in the second place, as they try
to use oxygen as pure as possible, it is possible that they seek the
goal they wish to reach by going beyond the maximum of oxygena-
tion that is really useful to oxidation. And so, this method, which,
it seems to me, should not be retained in most cases, amounts to a
violent shock of short duration, perhaps producing an effect op-
posite to that which is desired.
Henceforth I should like to see it used only in threatening cases
of asphyxia,11 poisoning by carbon monoxide1- or sewer gas, where
the time for action is short. Only air with about 60% of oxygen
should be used, and the inhalations should be continued for at least
an hour.
Attacks of asthma might also be favorably affected by these
inhalations, but much less, no doubt, than by compressed air, in
which mechanical action is added to chemical action.
But if is a matter of combatting a slow disease, like anemia,
my advice is to try to have the patient breathe, every day for
about two hours, a mixture with only 25% or 309'' of oxygen,
which would correspond to a compression of 20 to 35 centimeters.
Increased Pressure 1029
For this time, there would be needed at the most a total quantity
of one cubic meter of gaseous mixture, containing from 50 to 100
liters of added oxygen; little balloons of goldbeater's skin, with
perfumed washbottles, would do in practice, and the necessary
manipulations would soon become familiar to the patients. I am
deeply convinced that such a medication would give as good re-
sults as the use of compressed air.
I think that we have been a little too timid in the therapeutic
use of compressed air. Never, indeed, has any medical apparatus
gone beyond 2 atmospheres, total pressure; rarely has even this
pressure been reached. I think it could be carried without any
inconvenience to 3 atmospheres; as a matter of fact, the maximum
of intra-organic oxidations is at about this level, and if compressed
air acts favorably on patients by increasing the oxidations, we can
go that far logically.
Pravaz, we have seen, made some attempts towards the surgical
use of compressed air. I am surprised that he did not think of
recommending it in the case of strangulated hernias when the
intestine contains much gas which prevents reduction; at 2 atmos-
pheres, the volume of these gases would be diminished one-half,
at 3 atmospheres by two-thirds, which would make an important
difference. The taxis would, of course, be resumed in the ap-
paratus itself.
Finally, in certain stifling cases of tympanites, if one subjected
the patient to compressed air, the danger of suffocation would cease
immediately. Perhaps it would appear again if no medication
could check the disease; but it is worth trying. In all cases, the
patients should be kept in the cylinders until completely cured.
What would result from the medical use of very high pres-
sures, 3 atmospheres and more? The lessening of the combustions
would make this treatment an antiphlogistic, certainly; but would
not some other element enter into the matter? It is probable that
the attempt will not be made for a long time, at least by hospital
doctors. Those who care for caisson workmen and divers, we have
seen, have already had the opportunity to observe that oxygen at
high tension exercises a favorable action on inflammatory
symptoms.
B. Hygiene. Laborers who work on bridge piling and divers
in suits have not yet reached the degree at which the respiration
of compressed air becomes evidently dangerous, according to our
experiments: the strongest pressure yet attained was 4.25 atmos-
pheres at Douchy and 4.45 at St. Louis, U. S. A. And yet certain
1030 Summary and Conclusions
symptoms of anemia can be attributed to these high pressures.
But the symptoms of decompression complicate matters so that it
is impossible to make any statement.
But if the necessities of industry bring the use of pressure above
5 atmospheres, we can expect to see appearing in the workmen
symptoms the severity of which will increase rapidly; at 10 atmos-
pheres, I do not doubt that death will be frequent, and of course
I am speaking here only of the period of compression.
If the importance of this work is enough to justify great expense,
and such a case might present itself, for example, for pearl fishers,
or divers for sponges and especially coral, or men in divers' suits
engaged in salvaging valuable articles, the difficulty may be man-
aged: since the increase in the tension of the ambient oxygen con-
stitutes the danger, this tension must be lessened so that it varies
always somewhere between the normal amount of 21 and that of
60, which seems harmless. To reach it, the caissons would have
to be filled, not with ordinary air, but with air of low oxygen con-
tent. The apparatus with which M. Tessie du Motay prepares
oxygen could be used here; one could get from it, in fact, nitrogen
containing only very little oxygen. By mingling this nitrogen
with ordinary air in suitable proportions, one could easily secure
the desired proportions: at 8 atmospheres, for instance, to bring
the oxygen tension to 40, one would require air containing only
5% of oxygen. Hydrogen could also be used, and we know that
M. Giffard prepares it today at very moderate prices.
But if we imagine these serious difficulties overcome, we shall
find ourselves facing the dangers of decompression, greatly ag-
gravated by the enormous proportion of nitrogen which will be
dissolved in the blood. Accidents are frequent now, as we have
seen, even with ordinary air. But in the case of compression with
ordinary air, the only type which we have dealt with as yet, our
researches have brought us very important and very practical
conclusions.
As soon as the pressure employed has reached 2 atmospheres in
total pressure, close watch should be kept; there is as yet no true
danger, but already local pains appear, and besides, it is wise to
accustom the workmen to precautions early. The great precaution
is slowness in decompression.
I think that between 2 and 3 atmospheres, a half-hour should
be given to the decompression, to be perfectly safe; from 3 to 4 at-
mospheres, one hour, and the slowness of the decompression will
have to be assured by the degree of opening possible in the equi-
Increased Pressure 1031
librium cock. But now appears the serious disadvantage, the dan-
ger even, of the chilling that accompanies the expansion of the air,
with the condensation of moisture which is the result of it. To
ward it off, one must not only give the workman warm and dry
clothing, but also place in the decompression chamber heating
cylinders, with double hollow walls, through which pass jets of
steam, and which the workman can clasp, and against which he
can lean. I think that very simple and inexpensive arrangements
could settle the problem.
Besides, two chambers of decompression might be arranged,
both of them heated, so that one would pass, for example, from a
chamber of 3 atmospheres to one of 2, to stay there for a quarter of
an hour at the most and then go into the outside air; these double
"locks" would delay the service less.
The longer the workmen remain in the caissons, the more
slowly they should undergo decompression, for they must not only
allow time for the nitrogen of the bloocl to escape, but also allow
the nitrogen of the tissues time to pass into the blood. And as
this last point is the most difficult to obtain, the workmen must
not be given too long shifts of work, and must not be allowed to
enter the caissons more than once a day.
As for divers in suits, as they cannot be warmed, it would
perhaps be difficult to bring about the decompression for them
slowly by means of some mechanical and graduated windlass. But
nevertheless, when they return from great depths, 30 meters for
example, it is absolutely necessary either to bring them up on
some seat which allows them to be kept a good quarter of an hour
halfway up, or compel them to wait for a sufficient time in some
shallow place, when there is one within their working radius.
If, then, in spite of these different precautions, an accident
occurs, what is to be done? My researches have already answered
for us (Chapter VII, Subchapter IV) . If auscultation indicates
some gaseous gurgling in the region of the heart, immediately make
the patient inhale oxygen as pure as possible, which should always
be at hand in a rubber balloon, or better, compressed in quantity
in some steel reservoir. Then, when the gases have disappeared
from the heart, and death no longer seems imminent, subject the
patient immediately to a pressure greater than that from which
he came, then make the decompression very slowly. Furthermore,
when the pressure reaches 4 atmospheres, they should inhale oxy-
gen, especially divers, immediately after return to open air, without
awaiting the appearance of any symptom. When the decompres-
1032 Summary and Conclusions
sion shows its effects by paraplegia, recompression must be car-
ried on at once, without losing time in inhaling oxygen, especially
when the symptom did not appear until some time after the return
to the open air, for in this case we have to do, not with a general
obstruction of the pulmonary circulation, but with some bubble
of gas lodged in the vessels of the medulla, whose volume must be
reduced at once so that the blood may drive it out.
Workmen employed in compressed air may suffer other dis-
comforts which, though less serious, should not be completely dis-
regarded. Sudden expansion of the intestinal gases and the froth
formed in the liquids of the digestive tract may have consequences
which are annoying for the digestion and contribute to these dis-
turbances of the appetite which have often been noticed.
Moreover, the air in which they stay is anything but whole-
some. In the caissons of the bridge of Kehl, M. Bucquoy found
2.377o of carbonic acid (p. 373), and when the pressure rose
to 3V2 atmospheres, the workmen were, as we have proved, in the
same condition as if, at normal pressure, they had breathed air
containing 2.37 x 3.5 = 8.3% of CO.; and surely, such an atmosphere
would not be without danger. In the same way, other gases, the
carbon monoxide of incomplete combustions, the gases produced
by the explosions sometimes used in mines, or those wliich rise
from the ground, act in the double ratio of their percentage and
the manometric pressure; we have seen (p. 717) how quickly a
few drops of ether cause anesthesia in compressed air. We see
that energetic ventilation is absolutely necessary, and this point
has not been sufficiently emphasized, because the multiplying ef-
fects of pressure on the action of toxic gases were not known.
5. Conclusions from the Point of View of General Natural
History.
While speaking of diminished pressure, we have shown briefly
the part it plays in the general conditions of life on the earth and
in the geographical distribution of animals or plants.
The study of present nature shows us nothing comparable from
the standpoint of increased pressure, at least if we consider air-
breathing living beings: the few regions which are a little below
sea level (valleys of the Dead Sea and the Caspian) can hardly be
called populated. But the case is quite different, or at least it
seems so, for the beings which live in the waters of the sea at
depths which reach 4000 and 5000 meters.
First, if we consider in their habitat the creatures of the greatest
Increased Pressure 1033
depths, including the celebrated Bathybius, which, after playing
such an important part in the new philosophies of nature, seems to
have been relegated to mineral matter,13 it is clear that they
undergo no immediate and mechanical effect from the enormous
pressure to which they are constantly subjected and with which
they are perfectly in equilibrium. Circumstances would be dif-
ferent if an animal accustomed to live at 2000 meters were sub-
merged to 4000 meters, for example; the excess of pressure would
cause a lessening of the volume of its body, which very probably
would have a harmful effect on its organism. Conversely, an ani-
mal brought from a depth of 4000 meters to the surface will ex-
pand considerably (about 15 thousands of its original volume),
and this sort of distention of the tissues is largely responsible for
the death of animals caught in deep-sea dragging.14
The mechanical influence of compression or decompression acts
in a very effective and very energetic way upon animals equipped
with air bladders, especially when they are closed, as in sea fish.
In this case, as M. A. Moreau1' has satisfactorily demonstrated, any
sudden variation of pressure which, acting on the volume of their
bladder, can modify their average density enough to bring them
a few meters above or below their place of equilibrium, will, in
the first case, lift them to the surface, their bladder dilating to
the bursting point; in the second case, will make them sink in-
definitely in the depths of the ocean, their bladder contracting and
the density of their own body increasing in the same ratio as that
of the water. Let us note that since the natural variations of
barometric pressure do not exceed two centimeters of mercury
(26 cm. of water) per day, and the extreme variations are only 5
centimeters (65 cm. of water) at the most, the fish are not seriously
affected. Furthermore, as the remarkable experiments of M. Moreau
have shown, they can in time compensate for this influence, either
by secreting oxygen in their swimming bladder, or on the contrary
by absorbing the oxygen which it contains, and thus vary at the
same time its volume and their density.
We have seen that aquatic animals are killed by oxygen when
compression introduces a sufficient quantity of it into the water
(p. 777). But this dangerous effect can evidently take place only
if the compression acts first on the air and then forces into the
water oxygen in growing proportion, following Dalton's Law; but
the pressure exerted by the column of water itself upon its deep
parts does not at all modify the real tension of the oxygen. Fur-
thermore, direct analyses of the ocean water taken from great
1034 Summary and Conclusions
depths have shown that it contained less oxygen than surface
water. According to Lant Carpenter,10 the water of the ocean
would contain, on the average, no matter what the depth, 2.8
volumes of gas per 100 volumes of water; this gas would be con-
stituted as follows:
On the surface
On the bottom
Oxygen
25.00
19.53
Nitrogen
54.21
52.60
CO,
20.84
27.87
100.00 100.00
And so, less oxygen and a little less nitrogen. From this there
appear two conclusions:
First, a stay in the depths does not subject the animals to any
danger coming from decreased oxygen tension. In the second
place, sudden decompression should produce no harmful effect upon
the animals of the depths because they will not have an excess of
nitrogen dissolved in their tissues; and the truth of this is borne
out by the fact that no free gases have ever been found in the
tissues of a fish or an invertebrate brought up by the drag.
Circumstances would be greatly changed if some source of air
should suddenly gush up from the bottom of the sea. It would
need to come from only 100 meters, if it were chemically pure, to
kill rapidly all the beings it met on its way.
If we consider, for air-breathing animals as well as aquatic
animals, not the present epoch, but geological ages, we have every
reason to think that barometric pressure must have played an
important part in the appearance and the modification of life on
the surface of the globe. In the first ages of our planet, indeed,
the oxygen tension must have been much greater than today for
two reasons: the atmosphere was higher and its oxygen content
greater, since the rocks were not yet cooled and oxidized to so
great a depth. The epochs which follow us will no doubt see the
air enter further and further into the depths of the ground and
the oxygen diminish in it in growing proportion. So it is per-
missible to imagine that there was a time when present beings
could not have lived on the ground because of too great oxygen
tension, and that a time will come when they can no longer live
on account of its too weak tension. To go beyond this first plausible
hypothesis would be to adventure into the pure realm of fancy;
we shall leave to others this attractive and easy occupation.
Increased Pressure 1035
Perhaps, however, I shall be pardoned for noting that while the
three enemies of life as we know it today were, in the first geo-
logical ages, heat, oxygen tension, and carbonic acid tension, the
beings which are the most resistant to this triple and fatal influence
belong to the group of vibrios. It is also they which remain active
longest in rarefied air. Probably it is in them that life first ap-
peared, and it is in them that it will end on the surface of our
planet.
I Observations sur le scjour dans I' air comprime et dans different* gaa deletcrcs. Journal de
Robin, Vol. I, p. 452-470. L875. ,..,.. r, L -xj. *
3 Svgdomsformer hos Arbejdeme red Fastbroanlaegett over Limfjorden Ugeskrtft for
Laeger. Kjobenhavn, Nov. 25, 1876, p. 377-386.
3 Ucber die Sauerstoffaufnaliine in die Lungen bei geivohnhchcm und erhohtem Luftdrucl;.
Pfliigers Archiv., Bd. X, o. 479-536, 1875.
4 See Pfliiger's Archiv., Bd. IX, taf. VII, a: 1874.
5 Aerotherapie. Giessen, 1876. ,
6 The recent researches of M. Pasteur and myself en the virulent agent of carbuncled
diseases (charbon or anthrax) seem to indicate an exception to this general rule. The repro-
ductive corpuscles of certain vibrios which, as I have shown, retain their vitality for several
months in dilute alcohol, really resist oxygen tensions which kill the vibrios themselves. But
we should know whether it is not simply a question of amount in the tension, or of the duration
of the experiment. I am investigating this question, to which T cannot yet give an answer. (See
the Comptcs rendus de VAcadcmie des sciences. Sessions of May 21, July 9, July 30, 1877.)
7 See Pasteur, Etudes sur la bierc, p. 293. Paris, 1876.
8 Priestly, Experiments and Observations on Air, etc. Translated by Gibelm, Vol. 11, p.
9 For the history of the question see Demarquay: Essai de pnenmatologie medicale; Paris.
1866. See also the interesting pamphlet of Dr. Andrew Smith: Oxygen Gas as a Remedy in
Disease; New York, 1870. _ .
10 La chimie pneumatique appliquee aux travaux sous lean. Paris, 1S08.
II See Constantin Paul, De I'cmploi de foxygene en tlierapcutique, (Bull. gen. de therap.,
Aug. 15, 1S68, observ. I and III) and Limousin, Note sur le traitement de I asphyxic par le gas
oxvgenc; Bull, des travaux de la Soc. de med. pratique de Paris, 1871.
u See Linas and Limousin, Asphyxic par le charbon; traitement et guenson par Voxygene.
Societe de therapeutique ; July 17, 1868.
13 See C. Vogt, L' origine de /' hommc. Revue saentifiquc, number of May 12, 1877.
page 1090.
" See Wyville Thomson, Les abimes de la mer. Translated by Lortet. Paris, 1S75, page 27.
15 Recherches experimentales sur les fonctious de la vessie natatoire. Bihlioth. de VEcolc des
hautes etudes. Vol. XV, 1876.
16 In W. Thompson, Les abimes, etc. Appendix.
Chapter III
GENERAL CONCLUSIONS
The data given in the second part of this work, and the theories
which are deduced from them, and which are summarized in the
third part, can be condensed in the following conclusions, if we
omit the chapters dealing with poisoning by carbonic acid, as-
phyxia, blood gases, and other matters a little outside the subject
of this book:
A. The diminution of barometric pressure acts upon living
beings only by lowering the oxygen tension in the air they breathe,
and in the blood which supplies their tissues (anoxemia of M.
Jourdanet), and by exposing them thus to the dangers of as-
phyxia.
B. The increase in barometric pressure acts only by increasing
the oxygen tension in the air and in the blood.
Up to about three atmospheres, this increase in tension results
in somewhat more active intra-organic oxidations.
Beyond five atmospheres, the oxidations diminish in intensity,
probably change in character, and, when the pressure rises suf-
ficiently, stop completely.
The result is that all living beings, air-breathing or aquatic,
animal or vegetable, complex or monocellular, that all anatomical
elements, isolated (blood corpuscles, etc.) or grouped in tissues,
perish more or less rapidly in air that is sufficiently compressed.
The only exception to this generalization is the spores of certain
microscopic organisms. For the higher animals, death is preceded
by tonic and clonic convulsions of extreme violence.
In the vertebrates, the sudden symptoms due to too great oxy-
gen tension begin to appear only at the moment when the oxygen
goes into solution on coming in contact with the tissues, since the
hemoglobin is saturated with it. We can say then that the ana-
tomical elements are anaerobes.
1036
General Conclusions 1037
C. Diastases, poisons, and true viruses resist the action of oxygen
at high tension.
D. The harmful effects of lowered pressure can be effectively-
prevented by breathing an air sufficiently rich in oxygen to main-
tain the tension of this gas at its normal value (20.9) .
Those of increased pressure will be prevented by using air
sufficiently low in oxygen to secure the same result.
E. In a general way, the benign or harmful gases (oxygen, car-
bonic acid, etc.) act on living beings only according to their ten-
sion in the surrounding atmosphere, a tension which is measured
by multiplying their percentage by the barometric pressure; the
increase of one of these factors can be compensated for by the
decrease of the other.
F. When animals possess reservoirs of air either completely
closed (the swimming bladder of acanthopterygian fish, etc.), or
in communication with the air only during decompression (swim-
ming bladder of Cyprinidae, intestines of air-breathing vertebrates,
etc.) , or in communication with the air during compression as well
as decompression but by orifices that are too narrow (lungs of air-
breathing vertebrates, etc.) , the increase or decrease of pressure
may have physico-mechanical effects.
G. Sudden decompression beginning with several atmospheres
has an effect (except for a few cases included in F) only by allow-
ing to return to the free state the nitrogen which had become dis-
solved in the blood and the tissues under the influence of this
pressure.
H. The organisms at present existing in a natural state on the
surface of the earth are acclimated to the degree of oxygen tension
in which they live: any decrease, any increase seems to be harmful
to them when they are in a state of health.
Therapeutics can advantageously use these modifications in dif-
ferent pathological conditions.
I. The barometric pressure and the percentage of oxygen have
not always been the same on our globe. The tension of this gas
has probably been diminishing and no doubt will continue to
diminish. That is a factor which has not yet been taken into
account in biogenic speculation.
Their power of reaction against these different modifications
leads us to suppose that microscopic organisms must have appeared
first and that they will disappear last, when life becomes extinct
through insufficiency of oxygen tension.
1038 Summary and Conclusions
K. It is inexact to teach, as is ordinarily done, that plants must
have appeared on earth before animals, in order to purify the air
of the large quantity of CO., which it contained. In fact, germina-
tion, even that of molds, does not take place in air that contains
enough C02 to be fatal to warm-blooded animals.
It is just as inexact, as I remarked long ago, to explain the
earlier appearance of reptiles with reference to warm-blooded ani-
mals by the impurity of air containing too much CO.,; reptiles, in
fact, fear this gas even more than birds, and especially more than
mammals.
APPENDIX I
Table indicating very approximately the ratio between the altitude
and the height of the barometric column (the calculated altitudes are
taken from the book of M. Jourdanet, Vol. II, p. 331).
Orthez (105 m.) ; Reims (109 m.)
Dijon (217 m.); Tulle (222 m.)
Tarbes (302 m.) ; fipinal (317 m.); Privas (334 m.)
Brioude (424 m.); Gibraltar (438 m.)
Bagneres (556 m.); Toledo (563 m.)
Le Puy (625 m.); Grenada (681 m.)
Gap (729 m.)
Burgos (875 m.)
The Escorial (995 m.); Chamounix (1020 m.)
Barcelonnette (1130 m.)
Cormayeur (1218 m.); the Ballon d'Alsace (1250 m.)
Ispahan (1340 m.)
The Puy de Dome (1476 m.)
Porte, the.highest village in the Pyrenees (1625 m.)
Mount Ossa (1755 m.)
The Peak of Sancy (1897 m.); Erzeroum (1860 m.)
The Simplon Pass (2020 m.)
The Petit Saint-Bernard Pass (2160 m.)
Mexico City (2290 m.)
The monastery of the Grand Saint-Bernard (2470
m.); Mount Parnassus (2470 m.)
Santa-Fe de Bogota (2560 m.)
The pass of Mount Viso (2700 m.); Mount Cinto
(Corsica) (2710 m.)
Quinto (2910 m.)
Endschetkab in Abyssinia (2960 m.); Mount
Olympus (2975 m.)
The Simplon (3200 m.)
Etna (3310 m.); Mount Perdu ((3350 m.)
The Peak of Nethou (3405' m.); Cuzco (3470 m.);
Leh (3505 m.)
48 3659 Mont-Cenis (3620 m.); the Peak of Teneriffe
(3715 m). La Paz (3720 m.)
1039
Barometric column
Altitude
in centimeters.
in meters
76
0
75
105
74
212
73
321
72
430
71
542
70
655
69
769
68
886
67
1004
66
1123
65
1245
64
1368
63
1494
62
1621
61
1751
60
1882
59
2016
58
2152
57
2291
56
2432
55
2575
54
2721
53
2874
52
3022
51
3176
50
3334
49
3495
Barometric column
in centimeters.
47
Altitude
in meters
3827
46
3998
45
4173
44
4352
1040 APPENDIX I
Mount Argaeus (3840 m.)
Lake Titicaca (3915 m.)
The Jungfrau (4170 m.) ; Potosi (4165 m.)
Cerro de Pasco (4350 m.); the village of Chtfshul
(4390 m.)
43 4535 Mischabel (4550 m.); the monastery of Hanle
(4610m.)
42 4723 Mont Blanc (4810 m.); the tunnel of Oroya (4760
m.); the post-house of Rumihuani (4740 mi.)
41 4914 Pichincha (4860 m.); the village of Thok-Djalank
(4980 m.)
40 5111 Kasbek (5030 m.) ; the Grand Ararat (5155 m.); the
mines of Villacota (5042 m.)
Popocatepetl (5420 m.)
Elbruz (5620 m.); the pass of Karakorum (5650 m.)
The pass of Parang (5835 m.)
Cotopaxi (5945 m.)
Kilimandjaro (6110 m.); Misti (6100 m.)
Chimborazo (6420 m.)
Cerro de Potosi (6620 m.)
Aconcagua (6835 m.)
Doukia (7070 m.); Robertson's balloon (7170 m.)
Chamalari (7300 m.) ; Illimani (7310 m.)
Sorate (7560 m.)
Barathor (7950 m.)
Dawalaghiri (8185 m.)
Croce-Spinelli, Sivel, and Tissandier, in their bal-
loon.
24.8 8840 Mount Everest (8840 m.) ; Glaisher's balloon (8838
m.); myself, in my apparatus (See Exp. CCLVII).
39
5313
38
5520
37
5732
36
5950
35
6174
34
6405
33
6643
32
6888
31
7141
30
7402
29
7674
28
7951
27
8241
26.2
8600
APPENDIX II
Analysis of the recent work of Dr. Mermod
Just as I was about to authorize the printing of the last page,
I received from Dr. Mermod, of whom I have spoken before, a
work which is too interesting to be passed over in silence.
M. Mermod has compared the respiratory and circulatory
phenomena observed in himself during sojourns of several months
at Sainte-Croix (1100 m.), Lausanne (614 m.), Erlangen (343 m.),
and Strassburg (142 m.).
After reviewing his former observations on the acceleration of
the pulse, he noted (in this point contradicting what was said by
preceding authors, see pages 297 and 960) that the frequency of
the respiratory movements remained the same at Sainte-Croix and
at Strassburg, the obvious conclusion from which is that the ratio
between the number of respirations and that of the heart beats de-
creased as the result of residence at a higher altitude. The body
temperature remained unchanged.
But the most important part of M. Mermod's work is that in
which he compares the exhalation of carbonic acid in the two ex-
tremes of altitude.
The averages of the results which he obtained can be sum-
marized in the following table:
Strassburg Sainte-Croix
(Alt. 142m.; temp. 12.65° (Alt. 1100 m.; temp,
pressure 745 mm.) 12.68°; pres. 669 mm.)
Number of respirations per minute 11.15 11.24
Volume of gas expired per minute 5.85 liters 6.27 liters
This volume reduced to 0° and 760 mm. 5.48 liters 5.27 liters
Volume of each expiration 524 cc. 557 cc.
This volume reduced to 0° and 760 mm. 491 cc. 469 cc.
Weight of CO, expired per minute 0.375 gm. 0.402 gm.
Percentage of CO, in expired air 5.507 6.098
1041
1042 APPENDIX II
From these figures we draw the following conclusions:
1. The volume of air circulating in the lungs during a given
time and that which is brought in by a single inspiration are
greater at Sainte-Croix than at Strassburg; but their weight is
smaller;
2. The quantity of carbonic acid exhaled in a given time and
its proportion in the expired air are greater at Sainte-Croix than
at Strassburg.
I have no criticisms to make of the experimental and analytical
methods used by M. Mermod, and I consider his results accurate
under the conditions in which he obtained them.
But perhaps it would be premature to consider the preceding
conclusions general, even for the variations of altitude at which he
made the observations.
The author does not give us sufficient information about the
conditions and the time of his researches; he merely says that he
worked at Strassburg during the winter, and at Sainte-Croix dur-
ing the autumn. But was it in the same year or in different years?
In the latter case, his constitution might have undergone changes
which would explain the differences in the experimental results;
moreover, M. Mermod does not even speak of the weight of his
body. It is probable, besides, that the routine of his life, aside
from his diet about which he gives a few details, was not the same
on the mountain as in the city, and that might have a certain effect
upon the production of carbonic acid in a given time.
With even greater reason it seems unwarranted to apply the
preceding results, as M. Mermod has a tendency to do, to a resi-
dence in very lofty regions, where the bis or the soroche is preva-
lent. There, the sickly condition of travellers and even natives is
in marked contrast to the feeling of well-being which almost
everyone experiences at the low altitudes at which our author
made his observations. We refer the reader to what we said pre-
viously (page 998 et seq.) about the comparison of low altitudes
(below 2000 meters) with great altitudes, from the standpoint of
the effects of prolonged residence.
I am very anxious that M. Mermod should complete his inter-
esting experiments by closing the circle, that is, by repeating his
analyses beginning with Sainte-Croix, the place where he worked
before Strassburg; if he gets the same numbers, he will have re-
moved all objections, as far as low levels are concerned. It would,
finally, be extremely important to make observations following
Appendix II 1043
the same methods at La Paz (3720 meters) or Cerro de Pasco
(4350 meters) .
In conclusion, I shall mention briefly a question of priority
raised by M. Mermod. According to him, his preceptor, the emi-
nent chemist Hoppe-Seypler, discovered the cause of death by
sudden decompression and the fundamental reason for mountain
sickness sixteen years before I did.
In regard to the latter he quotes a notable page from the memoir
which I myself quoted (p. 248) , a page with which I agree entirely
today. But this passage shows only the keen mind of its author;
it is a pure hypothesis which Hoppe's own experiments contradict,
and which he renounces in explaining the death of animals sub-
jected to rarefied air. As for his share in the explanation of the
death of animals decompressed suddenly from several atmospheres,
I have specified that on page 455 of this book.
But I shall not dwell on these questions of priority which never
have more than a very slight interest.
INDEX
Acclimatization, to decreased pressure
balloons, 191, 192
Boyle's experiment, 201
in lofty places,
animals, 61, 234, 1005
men, 54, 292, 293, 295, 960, 1000; Euro-
peans, 263, 323, 324, 960, 1000-1004;
native races, 321, 322, 960
Achard, experiments on compressed air,
443
Acosta, description of mountain sickness,
24
explanation of mountain sickness, 195
Aeronauts, physiology of, 981-991
correlation of physiological effects with
altitude, 986-990
suggested precautions for, 990-991
Age factor in decompression symptoms,
366
Alcock, Rutherford, ascent of Fujiyama,
163
Alcohol, distaste for, in mountain sick-
ness, 216, 242, 251
effect in balloon sickness, 176, 178
effect in mountain sickness, 34, 61, 65,
76, 95, 99, 104, 105, 116, 117, 132
external use at high altitudes, 163, 189
Alps, ascents in, 77-120
early crossings, 5
individual peaks, 7
Altitude, variations in, in mountain sick-
ness, 316-318
Ancients, fear of mountains, 4
precaution against mountain sickness,
196
Anderson, Tempest, buccal temperature
during ascent. 957-958
Andes, see Cordillera
Andreoli, ascension with Brioschi, 181
ascension with Zambeccari, 178
Anemia, of altitudes,
Jourdanet, 259-260, 1004-1005
Anesthesia, from carbon dioxide, 921-924
d'Angeville, Mile., ascent of Mont Blanc.
96
Animals, acclimatization of, at high alti-
tudes, 61, 234, 1005
affected by altitude, 24, 28, 33, 135, 145.
153, 209, 960. See also Camels, Cats,
Cattle, Dogs, Hens, Horses, Llamas.
Mules, Yaks
in earlv experiments, 197, 198, 199, 200,
441, 443
Anoxemia, theory of Jourdanet on moun-
tain sickness, 255-261, 349-351
Anthrax, experiments on bacilli, 847-848
d'Aoust, Virlet, fatigue theory of moun-
tain sickness, 308-311
Apparatus, bellows for artificial respira-
tion, 591
compression chamber 756
for determining lethal concentration of
carbon dioxide in blood. 899
for elimination of carbon dioxide in air
in closed vessels, 575
for extracting blood gases, 581-584
for extracting blood under diminished
pressure, 594-596
for extracting blood under increased
pressure, 615-617
for measuring carbon dioxide produc-
tion while breathing superoxygenated
air, 765-767
for oxygen absorption by defibrinated
blood at high pressures, 654
for oxygen absorption by defibrinated
blood at low pressures, 643-644
for oxygen provision in mountain climb-
ing, 996-997, 1008 footnote 24
for pressures above one atmosphere,
552-555
for pressures below one atmosphere,
507-512
for study of intra-pulmonary pressure,
771-773
for study of putrefaction under con-
stant oxygen tension, 814
for use of oxvgen in decompression,
695-696
gas meter, 758
mercury pump, 509
mercury reservoir, 588
rebreathing apparatus for dog, 629-630
Aquatic animals, tolerance of high pres-
sures, 1032-1033
Ararat, ascents of, 125, 126, 127
d'Arcet, Doubt of rarefaction of air on
mountains, 213
d'Arlandes, Marquis, ascension with Pilatre
du Rozier, 171
Armieux, Dr., report on chest expansion
at moderate altitudes, 298-300
Arterial blood, oxygen content of; com-
parison of carotid and femoral, 587
Asphyxia, 928-935
cause of death at normal pressure, 928
cause of death under decreased pressure,
540, 579
comparison with decompression, 689-693
under 3 meters of water, 1010
Atkins, ascent of Mont Blanc, 95
Auldjo, ascent of Mont Blanc, 91
B
Babington and Cuthbert, dangers of de-
compression, 466
symptoms in caissons of bridge piers,
371-372
Bacon, Francis, explanation of mountain
sickness, 196
Barella, symptoms of miners in com-
pressed air, 384-386
1045
1046
Index
Barral, meteorological balloon ascension,
185
Barry, Dr. Martin, ascent of Mont Blanc,
95
discussed in Bibliolheque universelle of
Geneva, 230
Bauer, Dr., report of Eads Bridge patients,
387-388
Baysellance, report of caisson explosion,
382-383
Beale, Boyle's suggestions to, 203
Beaufoy, balloon ascension, 182
Beaufoy, Col, ascent of Mont Blanc, 84
Beclard, physiological effects of altitude,
382
Bembo, ascent of Etna, 69
Bernard, Claude, effect of capacity of ves-
sel on duration of life, 532
effect of illness on oxygen consumption,
529
experiments of, 560
lethal tension of carbon dioxide, 558
methods in toxicology, 839
sugar in liver in asphyxia, 689
theory of asphyxia, 506
Bertin, Eugene, therapeutic use of com-
pressed air, 454-455
Biot, ascension with Gay-Lussac, 179
Birds, effect of diminished pressure on,
176, 180, 190, 200, 211, 963, 976
comment on van Musschenbroeck on, 199
living at high altitudes, 57, 62, 159
used in Bert's experiments,
greenfinch (Loxia chloris, Lin.), 570,
693
green grosbeak (Fringilla chloris, Lin.),
696
gull (Larus ridibundus, Lin.), 686
hawk (Falco tinnunculus, Lin.), 542.
686
linnet. (Fringilla cannabina), 556-557,
565
owl (Strix psilodactyla, Lin.), 540-541
sparrow (Fringilla domestica and Frin-
gilla montana, Lin.), 513-538, 555-557,
559-563, 565-567, 570-573, 685-686, 694-
696, 697-699, 706-707, 710-713, 717-718,
737, 745, 856, 859-860
starling, 674
yellowhammer (Emberiza citrinella, 556
Bixio, balloon ascension with Barral, 185
Blanchard, ascension from Ghent, 173
ascension with five balloons, 175
controversy with de Lalande, 174
Blanchard, Mme., ascension from Turin,
182
Blavier, ascent of the Peak of Teneriffe.
75
physiological effects of compressed air,
361
Blindness, from decompression, 365, 385,
389, 492
Blood, color of, as indicative of oxygen
content, 939
in compressed air, 364, 365, 366, 367, 375,
542, 458, 461, 491
in Mexico, 980, 1000
in puppies, 939
experiments on, carbon dioxide accumu-
lation in, 913
carbon dioxide content of, 941
dissolved carbon dioxide of, 944-945
gases of, 646-657, 858
putrefaction in, 817-818
exposed to high oxygen tension in trans-
fusion, 842
Blood gases,
apparatus for extraction of. 581-584
discussion of, 935-946
early experiments on,
Boyle, 201
E. Darwin, 207
John Davy, 224
effect of diminished pressure on, 615
escape of, in mountain sickness, 342-343
Gavarret, 279
Guilbert, 254
in sudden decompression, 882-883
under diminished pressure, 460, 486, 858
Boyle, 201
Hoppe, 247
experimental procedure for extraction
of, 584-585, 935
in asphyxia, 932-935
physiological factors modifying propor-
tion of, 590
agitation, 592-594
former bleedings, 590
respiratory rate, 591-594
under increased pressure,
carbon dioxide, 625-627
nitrogen, 627-628
oxygen, 622-625
Body temperature,
in exercise, 289
in mountain climbing, 957, 959
Lortet, 114, 284-287, 339
Body weight, changes due to compressed
air, 473, 491
Bollaert, ascent of Tata Jachura, 36
Boorendo, Pass of, 136, 138
Borelli, ascent of Etna, 70
invention of "diver's bladder", 390
theory of effect of compressed air, 441
theory of effort as cause of mountain
sickness, 208
Veratti's quotation of, 204
Bouchard, Bert's refutation of his hypo-
thesis of hemorrhages, 881
hemorrhages and congestions in decom-
pression, 484-485
pathogeny of hemorrhages, 282
Bouchut, cause of mountain sickness, 949
Bouguer, experiences on Pichincha, 27
fatigue as cause of mountain sickness,
208
theory refuted by de Saussure, 216
Bouhy, symptoms of laborers in com-
pressed air, 368
Bourrit, Canon, ascent of Buet, 78
ascent of Mont Blanc, 88
comparison between air of Alps and that
of Cordilleras, 213
Boussingault, ascent of Chimborazo, 40
snow as factor in mountain sickness, 227
Boyle, Robert, account of symptoms of
mountain sickness on Ararat. 125
on the Peak of Teneriffe, 74
in the Pyrenees, 120
researches with pneumatic pump, 199-
202; on blood, 201, 858
suggestions for experiments, 203
Brachet, cause of panting in mountain
sickness, 235
Braddel, ascent of Mount Ophir in Malacca,
163
Brand, Lieut., passage of Cumbre, 35
Bravais, ascent of Mont Blanc, 100
Bridge foundations, use of compressed air
in construction of, 368-384, 386-390
Brize-Fradin, disadvantages of diving-bell,
356
sensations in diving-bell, 443-445
Brooke, ascent of Tabalau Indu in Borneo,
163
Brown-Sequard, theory of effect of carbon
dioxide, 674, 923
Brunei, use of Triger method in bridge
construction, 370
Bubbles, escape from organic liquids,
blood, 201
other organic liquids, 201
as cause of symptoms, 202
Buccal thermometer, criticism of, 287-288,
959
de Buch, Leopold, ascents of Peak of
Teneriffe, 75
Bucquoy, confirmation of theory by Bert's
experiments, 881
physiological effects in caissons, 373-375
Index
1047
theory of symptoms of compression and
decompression, 457-460
Buksh, the "Munschi" Faiz, in Pamis, 157
Burdach, effect of atmospheric pressure
on circulation, 225
Burkhardt, susceptibility of horses and
mules to mountain sickness, 60
Burmeister, symptoms of Puna, 52
Burnes, Al., on pass of Hindu-Koush, 144
Burton, in Kamerun mountains, 161
origin of mountain sickness, 296
Butterflies, at high altitudes, 158
Byron, Commander, ascent of Mauna Kea
(Hawaii), 164
Caffe, study of compressed air, 465-466
Caisson, construction of compressed air,
368-369
Calberla, rectal temperature in ascent, 959
Caldcleugh, experiences in crossing the
Andes, 34
de Calvi, Marchal, effect of atmospheric
pressure, 240
Camels, effect of altitude on, 153, 154, 322
Campana, immunity of certain birds to
effects of rarefaction, 976-978
Carbon dioxide, accumulation in tissues,
910-914
action upon living beings, 896-927
anesthesia by, 921-924
cause of mountain sickness, 949-950
emanations of, 238
excess in blood in mountain sickness,
274-275, 286, 346-347
in asphyxia, 934-935
lethal concentration in blood, 899-910
lethal tension in ambient air, 558, 563-
564, 574, 578, 896-899
differences in animal species, 897-899
of blood, 940-946
of blood under increased pressure, 625-
627
poisoning by, 914-924
production on Mexican plateaux, 263
production under normal and increased
pressure, 1017-1019
role of, in death in confined air, 524, 578
saturation point in blood, 913
summary of effects of, 927
Castel, effect of decrease of atmospheric
pressure, 235
de Castelnau, effects of soroche on ani-
mals, 47
Cats, effect of altitude on, 40, 46, 233, 322,
1008 footnote 30
experiments on temperature compared
to oxygen consumption, 219
resistance of kittens to diminished pres-
sure, 200, 545-546, 687
Cattle, effect of altitude on, 29, 47, 54.
154, 322
Caucasus, individual peaks, 10
Cavaroz, hematosis on the Mexican pla-
teaux, 269-270
Cezanne, physiological effects of com-
pressed air in industry, 370
Chabert, Dr., causes of mountain sickness,
951
Charles, invention of hydrogen balloon,
171
symptoms in ears in ascension, 172
Chauveau, research on vaccine, 846
Cheetam, on pass of Lunga-Lacha, 152
Chemical fixation of oxygen of blood
Longet, 250
Gavarret, 250
Chest capacity, increase at higher altitude,
Bareges (1270 meters), 298
Cordilleras (2500-5000 meters), 301
Mexico, 302
Chodzko, ascent of Ararat, 127
Chomel, ascent of Mont Blanc, 106
Cigna, J. Fr., experiments on sparrows
under diminished pressure, 205
Cimento, Academy del, experiments on
animals (1667), 197, 441
Circulation, in compressed air,
amplitude of pulse, 396
capillary circulation, 397, 445, 491
congestions, 451
pulse rate, 374, 396
pulse rate in decompression, 366
Clark, Dr., ascent of Mont Blanc, 91
Clifford-Albutt, body temperature in moun-
tain climbing, 289
Clissold, F., ascent of Mont Blanc, 90
theory of mountain sickness. 223
Cloquet, Hipp., mechanical explanation of
mountain sickness, 223
mountain sickness at the Grand Saint-
Bernard, 94
Closed vessels, death in,
early experiments on, 204, 205
Coca, prophylactic power of, 305
Coindet, report of carbonic acid produc-
tion on the Mexican plateaux, 277
controversy with Jourdanet, 261-269
Cold, effect in balloon ascensions, 988
factor in mountain sickness, 326, 327
"physiological", study by Martins, 252
Cold-blooded animals, early experiments
on, 200, 201
in Bert's experiments,
adder, 898
carp, 854, 925
eels, 752-753, 777, 889-890,
frog eggs, 776, 777
frogs, 550, 716, 717, 768, 898
lizard, 751, 898
sticklebacks, 855
tadpoles, 753, 777, 778
susceptibility to carbon dioxide, 897-898
Coleman, ascent of Mount Baker and
Mount Rainier, 69
Colin, intestinal gases in rarefied air, 950
Colladon, Dr., descent in diving-bell, 356-
357
Comaschi, balloon ascension at Turin. 185
Compressed air (1 to 2 atm.), effects of
circulation, 413, 415, 416, 417, 423, 433, 436
theories about, 449, 452, 475, 478, 480
gaseous exchanges, theories about, 447,
448, 450, 452, 455, 458, 468, 471, 479, 481
heat production, 415, 433, 434
innervation, 432, 477
nutrition, 414, 415, 417, 433
theories about, 473, 477
pulmonary capacity, 418, 432, 435
respiration, 413, 416, 417, 418, 420, 432.
435, 436
thoeries about, 447, 457, 475, 478, 482
secretions, 414, 416, 417, 455, 473
Compressed air (1 to 5 atm.), effects of,
circulation, 764, 773-775
intra pulmonary pressure, 771-773
nutrition, 764
prolonged stay in, 775-779
pulmonary capacity, 768-771, 1026
respiration, 763-764
Compressed air, explanation of effects of.
chemical, 498
physico-mechanical, 494
Compressed air, use in industry, 247
in bridge foundations, 368-384
in diving-bells, 252
in mines, 361-368
measures for preventing dangers in use
of, 1030-1031
relief of symptoms resulting from use
of, 1031-1032
Compression, sudden, effect of, 852-853
Compression, symptoms due to, see Cir-
culation; Ears, pains in; Innervation;
Nutrition; Respiration; Secretions; Voice
Comte, explosion of compressed air, 367
Condor, causes of its immunity to decom-
pression, 976-978, 1005-1006
1048
Index
height of flight, 31, 57, 542, 1005
Congestion in comprsesed air, theories
about, 452
Contractility, muscular, effect of carbon
dioxide at high tension on, 926-927
Cordillera, individual peaks and topog-
raphy of, 12
Cordier, ascent of Maladetta, 121
ascent of Peak of Teneriffe, 75
Courtois, thesis on symptoms of moun-
tain sickness, 218
Coxo-femoral articulation, relaxing of, 254,
343-344
Beclard, 282
. Jourdanet, 257-258
Lombard, 244, 252
Meyer-Ahrens, 243
Coxwell, as balloon engineer for Glaisher,
186-191
Craveri, ascent of Popocatepetl, 63
Croce-Spinelli, ballon ascension in Polar
Star, 961-962
ascension organized by Society of Aerial
Navigation, 192-193
experiment in decompression chamber,
700-703
fatal ascension in Zenith, 963-969
funeral eulogy, 971-974
Crozet, ascent of Mont Blanc, 106
Cumbre, the puna on, 33, 34, 35, 36
Cunningham, electricity as cause of moun-
tain sickness, 225
Cupping-glasses, comparison to rarefied air,
217,
of Dr. Junod, 229
Curare, used for paralyzing, 591, 593, 769
Cuthbert, see Babington
Darwin, Charles, passage of the Andes, 43
Darwin, Erasmus, experiment on blood un-
der diminished pressure, 207
Davaine, Dr., research on anthrax, 847
Davy, John, experiments on gases of the
blood, 224
Deafness, improvement under compression,
359
result of decompression, 364, 365, 378, 492
Death, from decompression, 364, 365, 371,
378, 395, 405
theories about, 455
Decimals, futility of, 389, 513, 522, 589
Decken, Baron de, attempted ascents of
Kilimandjaro, 162
Decompression, comparison with asphyxia,
689-693
explanations of effects of, 500
explosive,
in accidents, 367, 371, 382, 383, 359, 868
effects of, 882-883, 886
speed of, 360, 362, 367, 372, 377, 378, 383,
384, 386, 387, 389, 394, 460, 487, 493, 494.
895, 1013, 1030
sudden, effects of, 878-889
from one atm., 853-858
from several atm., 859
in stages, 874-878
without interruption, 859-874
ill health as factor in resistance to, 880
.prevention of,
by oxygen inhalations, 884
by slowness of decompression, 890
relief of,
inhalation of oxygen, 891
recompression, 890
variations in individuals, 889
variations in species, 878-880
symptoms due to, see Blindness, Deaf-
ness, Death, Duration of, "Fleas",
Muscular pains. Paralysis, Respiratory
difficulties, Time of appearance
Delon, ascent of Etna, 70
Demavend, ascents of, 128
Demeunier, ascent of Etna, 70
Denayrouze, diving apparatus, 392
symptoms of divers, 395
Denial of existence of mountain sickness,
119, 308, 310
Desor, ascent of the Jungfrau, 96
Devices suggested to prevent effects of
high altitudes, 974
Deville, Charles Sainte-Claire, ascent of
Peak of Teneriffe, 76
Diminished pressure in therapeutic ap-
paratuses,
Gondret, 220
Junod, Dr., 228
Diving-bells, 355-358
Diving suits, 39CK410
Dobereiner, experiments on germination,
781
Dogs, effect of altitude on, 37, 40, 46, 61,
96, 154, 233. 322
Dollfus, A., journey to Popocatepetl, 60
Dolomieu, ascent of Etna, 70
Dortheren, ascent of Mont Blanc, 88
Douglas, David, ascents in Hawaii, 164
Dralet, conditions in lofty places, 219
summary of data in Pyrenees, 120
Drew. Fr., discussion of mountain siGk-
ness, 295
geography of Jumnoo and Cashmere, 160
Drowsiness, in compressed air, 492
Dufour, factors producing mountain sick-
ness, 951-953
muscular exhaustion as cause of moun-
tain sickness, 289
Dumas, Dr. Aug., explanation of symp-
toms of mountain sickness, 275
Duration of symptoms due to decompres-
sion, 364, 372, 373, 380, 382, 386, 387, 389,
404, 407, 493
Durier, ascent of Mont Blanc, 114
importance of training in ascents, 293
Duval, Dr., digestive symptoms in moun-
tain sickness, 251
Dwellers in high places, 998-1005
physiological effects on,
great heights, 1000-1005
moderate heights, 998-999
Dwellings at high altitudes, 19, 45, 141, 154,
Eads, report on Mississippi Bridge labor-
ers, 386-387
Ears, pains in, from compression, 356, 357,
359, 362, 363, 370, 371, 373, 489-490
means of preventing, 357, 363, 490
Edens, ascent of Peak of Teneriffe, 74
Eggs, experiments on putrefaction of, 819-
820
Elbrouz, ascents of, 124, 125
Electricity as cause of mountain sickness,
221, 225, 245, 337
Elliotson, effect of rarefied air on dogs, 61
Elsasser, respiration in compressed air, 435
theory of effects of compressed air, 478
Emulsin, experiments on, 839
Engelhardt, ascent of Kasbek with Parrot.
123
Estor and Saint-Pierre, extraction of
oxygen of blood, 585-587
Etna, early ascents, 4
later ascents, 69-73
Exhalations as cause of mountain sickness,
238, 336
Exhilaration in compressed air, 357, 417.
492
Experimental procedure,
for determining amount of dissolved car-
bon dioxide ni blood, 943
for determining blood gases in oxygen
poisoning, 719
for determining accumulation of carbon
dioxide in tissues, 910-911
Index
1049
for determining oxygen capacity of blood
under high pressures, 654
for determining oxygen capacity of blood
under low pressures, 644-645
for determining oxygen capacity of gas-
free blood, 649-651
for extraction of blood under diminished
pressure, 596-600
for extraction of blood under increased
pressure, 617-618
for extraction of blood gases, 584-585, 941
accuracy of method, 587-589, 594
for low pressures, 644-645
for mercury pump, 510-512
for pressures below one atmosphere, 508-
509
for rebreathing experiments, 630
for very low pressures with super-
oxygenated air, 536
for studying effects of increased pres-
sure, 757-760
in experiments on putrefaction, 810-811
Experiments of Bert
at various pressures
at normal pressure, 513
air with reduced oxygen content,
630-633
blood gases, 586
low temperature, 533-535
venous blood, 636-638
less than one atmosphere, 514-522, 529,
540-542 543
blood gases, 600-605, 613-614
capacity of blood for oxygen, 646-651,
high temperatures, 652-653
superoxygenated air, 537-538, 560-563
more than one atmosphere
blood gases, 618-620
capacity of blood for oxygen, 655, 657
low oxygen content, 579
ordinary air, 555-557; at low tem-
perature, 559-560; under very high
pressures, 565-567, with carbon di-
oxide eliminated, 575
superoxygenated air, 571-573
on lower forms
anatomical elements, 840-842
ferments, 800-839
fruit, dry rot, 843-844; ripening, 844-
845
plants, germination, 782-786, 789-791,
792-796; vegetation, 787, 797
scorpion's venom, 845-846
viruses; anthrax, 847-848: glanders, 847;
vaccine, 846-847
with various purposes
air injections into blood, 888-889
asphyxia, 928-934
carbon dioxide accumulation in tissues,
911-913
carbon dioxide content of blood, 941
dissolved carbon dioxide of blood, 944-
945
effects of carbon dioxide on lower or-
ganisms, 925-927
lethal concentration of carbon dioxide
in blood, 899-909
lethal tension of carbon dioxide, 897-898
relieving symptoms of decompression,
890-894
sudden decomposition from 1 atmos-
phere, 854-856
sudden decompression from several
atmospheres, 859-874
Experiments, early, with compressed air,
441, 446
with diminished pressure, 197
Explanations of mountain sickness, see
Anoxemia; Blood gases, escape of; Car-
bon dioxide excess in blood; Cold; Coxo-
femoral articulation, relaxing of; Elec-
tricity; Exhalations; Fatigue; Intestinal
gases, expansion of; Oxygen lack in air;
Weight of air sustained by body, de-
crease of
Fatigue as cause of mountain sickness.
325, 340, 284, 952, (Bouguer) 208, (Dufour)
291, (Hudson) 283, (Lepileur) 236, (Mar-
tins) 231
Fatigue on mountains, explanation of,
(von Humboldt) 228
Favre, principles of Junod method (hemo-
spasie), 230
Fazello, ascent of Etna, 70
Fellowes, ascent of Mont Blanc, 91
Fermentations, experiments on, under high
oxygen tension, 800-839
diastatic fermentations, 834-839
emulsin, 839
inversive fermnet of yeast, 838
myrosin, 838
pepsin, 837-838
saliva and diastase, 835-837
true fermentations, 800-834
brewers yeast, 826
coagulation of milk, 820-823
molds, 831-834
putrefaction, 800-816; blood, 817-818;
eggs, 819-820; meat, 800-816
urine, 823-825
wine, 827-881
Fernet, on blood gases,
carbon dioxide in solution in saturated
blood, 942
experiments on blood gases, 249; his con-
clusions, 611, 641; discussion of experi-
ments, 611, 641; validity of conclusions,
653
nitrogen content of blood, 936
Ferrara, ascent of Etna, 71
Feuillee. Pere, ascent of Peak of Tene-
riffe, 74
Fileteo, ascent of Etna, 69
Fish, early experiments on, by Academy
del Cimento, 197; by Boyle, 200; by
French Academy of Sciences, 199
"Fleas" (puces), 373, 377, 381, 398, 461, 464,
487
explanation of, 886
Flechner, oxygen content of mountain air,
234
Flemeing, causes of mountain sickness, 281
Focke, mention of sorocho, 55
Fodere, explanation of hemorrhages in
rarefied air, 217
Foley, Dr., effects of insufficient hematosis,
270
physiological phenomena in compressed
air, 375-378
suggestion for therapeutic use of com-
pressed air, 464-465
theory of caisson disease, 462-464
Food, as factor in prevention of balloon
sickness, 990
as factor in prevention of mountain sick-
ness, 325, 290, 291, 292. 293, 335, 996
Forbes, expeditions on Alps, 98
de Forbin, Count, ascent of Etna, 72
Forel, ascent of Monte Rosa, 954-957
criticism of buccal thermometer, 287
effects of low oxygen tension, 953-954
increase of temperature while walking,
287, 289
Forneret, ascent of Mont Blanc, 88
Frangois, Dr., physiological and pathologi-
cal effects in caissons, 372-373
Frankland, ascent of Mont Blanc with
Tyndall, 107
Fraser, discussion of effect of odor of
flowers in mountain sickness, 221
effects of mountain sickness in Hima-
layas, 132
Fremont, Col., expedition to the Rocky
Mountains, 68
Freshfield, Douglas, ascents of Kasbek and
Elbrouz, 124
Freud, pulmonary capacity in compressed
air, 435
1050
Index
Frezier, explanation of mountain sick-
ness, 26
Fruit, experiments on, dry rot, 843-844:
ripening of, 844-845
Fujiyama, ascents of, 163
de Franqueville, ascent of Nethou, 122
Gal, Dr. Alphonse, pathogeny of caisson
disease, 486-487
physiological observations on divers,
395-405
Gallard, Dr., report of deaths in caisson
explosion, 383-384
Gamard, ascent of the Jungfrau, 118
Gardiner, ascent of Elbrouz, 125
Garnerin, Jacques, ascension from Mos-
cow, 177
use of parachute, 177
Gas analysis, method used by Bert, 512
Gavarret, article Atmosphere in Diction-
naire Encyclopedique, 279
effect of air pressure on hematosis. 250
effect of excess carbon dioxide in blood,
274
hemorrhages in decompression, 482
Gay, Claude, soroche in the Cordillera, 45
Gay-Lussac, altitude reached, 174
ascension with Biot, 179
symptoms noted in later ascension, 180
Gerard, Alexandre, journeys in Himalayas,
134-138, 154, 221-223
Gillis, Lieut., symptoms of mountain sick-
ness, 49
Giraud-Teulon, refutation of mechanical
explanation of mountain sickness, 245
i1?9her' comment on report of Andreoli,
series of ascensions with Coxwell, 186-
suggestion of artificial aid to respira-
tion, 191
summary of physiological svmptoms in
ascension, 190
Glanders, experiments on, 847
Glas, G., ascent of Peak of Teneriffe, 74
Glennie, Lieut, W., attack of soroche, 61
Godwin-Austen, Capt., in Himalayas, 155
Gondret, explanation of symptoms of
mountain sickness, 220
Gosse, anatomy of Peruvian Indians, 302
questionnaire on mountain sickness, 303
de Gourbillon, ascent of Etna, 72
de la Gournerie, compressed air in boat,
361
Govan, Dr., electricity as cause of moun-
tain sickness, 221
Grafts, animal, effect of oxygen at high
tension on, 841
Grandidier, E., discussion of soroche, 51
Grene, balloon ascensions, 183
balloon engineer for Welsh, 186
inaccuracies of statement, 184
Gros, Baron, ascent of Popocatepetl 61
Grove, Craufurd, symptoms on the Alps,
Gubbins, ascent of Fujiyama, 163
Guerard, A., weight supported in com-
pressed air, 453
Guericke, Otto von, invention of pneu-
matic pump, 196
Guichard, respiration in compressed air.
Guilbert, Dr. Charles, description of so-
roche in La Paz, 53
explanation of mountain sickness, 254
Guinea pigs, experiments on temperature
and oxygen consumption, 219
Gunnison, Capt., ascent of Mount Creek.
Col.. 68
H
Haigh, Samuel, symptoms of mountain
sickness on Cumbre, 33
Halle and Nysten, physiological effects of
compressed air, 445
theory of hemorrhages in rarefied air, 217
theory of respiration in rarefied air, 217
Haller, effects of compressed air, 443
effects of rarefied (mountain) air, 210-211
Halley, Dr., improvements in diving-bell
355, 390
Hamel, Dr., ascent of Mont Blanc, 89
descent in diving-bell, 356
plans for experiments on Mont Blanc.
223
Hamilton, ascent of Argaeus, 127
Hardwicke, Capt. Thomas, in Little Thibet,
131
Hardy, ascent of Finsteraarhorn, 116
Hawaii, ascents in, 164-165
Hawes, ascent of Mont Blanc, 91
Hayward, in Little Thibet, 156
Hearing in compressed air, 357, 492
Heart beats, persistence of, in carbon di-
oxide poisoning, 920
Heiberg, Dr., symptoms of caisson-workers,
1011-1013
Hematosis in compressed air, 458
Hemorrhages, causes of, 281-282
in compressed air, 356
from decompression, 370-373, 387. 398
theories about, 457, 464, 482, 484
in mountain sickness, 331
Henderson, observations in Himalayas, 157-
159
symptoms from poisonous artemisia. 295
Hens, effect of high altitude on, 40
Hermel, Dr.,-- case of caisson disease. 379-
380
explanation of symptoms, 460-462
de Herrera, 26
Hervey, Mistress, adventures in Himalayas,
147-152
poisonous plant as cause of mountain
sickness, 294
Hervier and Saint-Lager, carbon dioxide
formation in compressed air, 446-447
Heusinger, effect of diminished pressure at
high altitudes, 245
Hill, symptoms and cause -of mountain
sickness, 233
Himalayas, ascents of, 129-160
individual peaks of, 10
Hines, ascent of Mount Hood, Oregon, 69
Hiouen-Thsang, on Hindou-Kouch and
Pamir, 129
Hobard, .ascension from Lynchburg, Va..
185
Hodgson, Capt., plant exhalations in
mountain sickness, 223
Hoffmeister, in Thibet, 145
Hooker, Dalton, symptoms of mountain
sickness, 146
Hoppe, Felix, experiments on death in
rarefied air, 247
ascribes death to free blood gases, 248
theory applied to sudden decompression.
455-456
Horses, effect of high altitude on. 32, 36.
40, 43, 46, 47, 52, 60, 132, 134, 144. 153. 154.
156, 159, 173, 234, 272-273, 322
Houel, ascent of Etna. 70
Hue, Pare, passage of Bourhan-Bota, 144
symptoms of mountain sickness ascribed
to carbon dioxide. 238
Hudson, precautions against mountain
sickness, 283
Hugi, ascent of Finsteraarhorn, 94
Human beings, experiments on.
Himself, 669, 697-699. 703-704. 706-707.
760-763
Regnard, 763
Sivel and Croce-Spinelli. 700-703
Index
1051
von Humboldt, ascents of Chimborazo and
Antisana, 29; of Peak of Teneriffe, 75
explanation of fatigue on mountains, 228
Hume, A. O., birds in Himalayas, 159
Hunt, Dr. J., attraction of North Pole, 296
Huyghens and Papin, theory of death of
animals in vacuum, 202
I
111 health, factor in mountain sickness, 326
factor in resistance to sudden decom-
pression, 880
Innervation, changes in compressed air, 492
Insects at high altitudes, bee, 179; butter-
flies, 158
Insects, experimental, fly pupae, 776; midge
larvae, 778; mosquito larvae, 778; poplar
beetle, 552; silkworm cocoons, 684-685,
752, 776; various species, 751
in early experiments, 201
Insomnia, factor in mountain sickness, 325
Intestinal gases, expansion of, in balloon
sickness, 307
in mountain sickness, 343, 950
Itier, ascent of Peak of Teneriffe, 76
Jaccoud, Dr., physiological effects of mod-
erate altitude, 296-298
Jacquemont, experiences in Himalayas,
139-142
Javelle, psychological factors in mountain
sickness, 292
Jeffreys, ascent of Fujiyama, 163
Joanne, symptoms of mountain sickness,
118
Johnson, Capt., ascent of Tazigand, 139
Jourdanet, Dr., anatomy of Mexican In-
dians, 302
Anemia of Altitudes, 259-260
"Barometric disoxygenation of the
blood," 261
controversy with Coindet. 261-269
Effects of Barometric Pressure on Hu-
man Life, 979-980
effects of rarefied air in Mexico, 255-259
oxygen content of blood in Mexico, 642
theory of anoxemia, 349-351
Junod, Dr., barometric apparatus for gen-
eral treatment, 228
cupping-glasses, 230
Magendie's report on work of Junod, 229
therapeutic effects in compressed air,
413-414
Kamerun Mountains, 161
Karakorum, Pass of, 129, 145, 155, 156, 975
Kasbek, ascents of, 123, 124
Kaufmann, effects of altitude on physio-
logical functions, 276
Kennedy, ascent of the Dent Blanche, 117
Kilimandjaro, ascents of, 161, 162
Kini-Ballu, ascent of, 162
Kupffer, ascent of Elbrouz, 124-
Laborde, ascent of Mont Blanc, 78
La Condamine, experimences on Pichin-
cha, 27, 174, 175
weight of air on body, 210
Ladak, 130, 137, 148, 149
de Lalande, ascension with Blanchard, 175
criticism of Blanchard, 175
Lange, Dr. G., physiological effects of
compressed air, 417
respiration and circulation in com-
pressed air, 475-478
Laverriere, ascent of Popocatepetl, 63
Leblanc, Felix, oxygen percentage in air
of mines, 692-693
Legallois, researches on animal heat, 218
Le Guillou, mountain sickness on Peak
of Teneriffe, 76
Lepileur, ascents of Mont Blanc, 100
causes of mountain sickness, 236
summary of Auldjo's ascent of Mont
Blanc, 91
symptoms of mountain sickness, 98
Leullier-Duche, Louis, use of balloon
ascensions in therapeutics, 172
von Liebig, George, carbon dioxide pro-
duction in respiration, 481-482, 1017-1019
mechanical action of increased pressure,
1020
pulmonary ventilation under normal
and increased pressure, 1019
respiration in compressed air, '437
Light, action of, in mountain sickness, 242,
245
Liguistin, mountain sickness in horses in
Mexico, 271-273
Limited mountains; Etna, 73; Peak of
Teneriffe, 77
Limousin, Dr, case of caisson disease,
381-382
Llamas, effect of altitude on, 323
Lloyd, mountain sickness, 50
Loevenstern, ascent of Mauna Loa, Ha-
waii, 164
Lombard, decrease of weight sustained in
rarefied air, 243
oxygen content of rarefied air, 251
Longet, effect of air pressure on hema-
tosis, 250, 642
Lortet, functional disturbances in moun-
tain climbing. 111
cold as cause of mountain sickness, 284.
683-684
report of ascent of Mont Blanc, 109
Low, in Borneo, 162
Lowe, mountain sickness, 44
de Luc, experiences on Buet, 212
Lungs, retraction under decreased pres-
sure, 204-205, 345
de Lusy, Count, ascent of Mont Blanc, 88
M
Magendie, report on work of Junod, 229
Magnus, experiment on blood gases, 641
Maissiat, effect of compressed air on in-
testinal gases, 446
influence of expended intestinal gases,
234
Malezieux, reports on Eads and Brooklyn
bridges, 388
Mammals used in Bert's experiments, 542
cats, 543-545, 662, 773, 856, 861-863, 875
dogs, 546, 586, 590, 591-594, 600-605. 613-
614, 618-620, 630-633, 636-638, 661-662.
672, 679-680, 682-683, 720-733, 737, 748-
749, 769-770, 773-774, 854, 856, 863-870
876,877, 888-889, 890-894, 899-909, 928-
931 934
guinea pigs, 547-549, 664-665, 874
hedgehog, 550
rabbits, 546-547, 662-664, 737. 861, 875
rats, 675-677, 681-682, 706-707, 718, 745,
746, 750, 768, 856, 861, 897
Manasarowar, Lake, 130, 131, 134, 135, 141
Mann, in Kamerun Mountains, 161
Marc, therapeutic effect of compressed
air, 437-438
Marcet, Dr. W., ascent on Mont Blanc
with Lortet, 109
cold as cause of mountain sickness, 286
Markham, attacked by soroche, 52
Martins, Ch., ascent of Mont Blanc, 100
disbelief in mountain sickness, 231
physiological cold, 252-254, 348
Mathieu and Urbain, oxygen content of
blood of various arteries, 587
1052
Index
Mayer, physiological effects in compressed
air, 437
Meat, experiments on, putrefaction, 800-
816
Mechanical explanation, of death in
vacuum, 202
of decompression, 980
Mercury pump, description of, 509
inventor of, 511
operation of, 511-512, 582-585
de Mericourt, Leroy, article Altitudes in
medical encyclopedia, 273
article Hygiene of sponge fishers, 393-394
paralysis after decompression, 482-484
Mermod, Dr., moderate altitudes, pulse
rate at, 330
respiratory and pulse rate at, 1041-1042
Meyer, ascent of Mont Blanc, 92
Meyer-Ahrens, Dr., memoir on symptoms
of decompression, 241-243
Meyers, symptoms of sorocho. 42
Miers, symptoms of puna on Cumbre, 34
Milk, experiments on, 820-823
Milliet, Dr., physical action of compressed
air, 453-454
physiological effects of compressed air,
416
Minerals as alleged cause of mountain
sickness, 26, 33, 36, 37, 42, 48, 49, 51, 55,
58, 209, 227, 232, 233
Mines, compressed air in, 361-368, 384-386
Mirza, The, in Pamir, 156
Missionaries, in Central Asia, 129
Molds, experiments on; bread, 831-832;
cooked starch, 832-833; fruits, 833-834
Molinatti, ascent of Monte Rosa, 93
Mont Blanc, ascents of, 78-96
Monte Rosa, ascents of, 93-94
de Montserrat, journey to Popocatepetl, 60
Moorcroft, journey through the Himalayas.
131
Mossbach, mention of sorocho, 55
Mountain sickness, see Animals affected
by altitude; Conditions of appearance
of; Denial of existence of; Explanations
of; Names given to; Prevention of; Psy-
chological factors in; Remedies for;
Symptoms of
Mountain sickness, variations in effects
of, 318-328
questionnaire on, 303-305
Mountain systems, Asia, 10; Europe, 5
Mountain travellers, 991-998; muscular
effort, 992-995: rate of ascent, 995-996
de Moussy, Dr. Martin, symptoms of puna,
52
Mulahacen, ascent of, 123
Mules, effect of high altitude on, 26, 32, 36,
37, 40, 43, 47, 51, 53, 54, 55, 60, 88, 118,
226, 234, 322
von Muller, ascent of Orizaba, 66
Murray, Mrs. Elizabeth, report of ascent
of Peak of Teneriffe, 76
Muscular pains from decompression, 360,
361, 363, 364-366, 377, 398
theories about, 456, 457, 462
Muscular swellings due to decompression,
492; theory about, 485
van Musschenbroeck, experiments on ani-
mals in compressed air, 441-442
explanation of effect of vacuum, 198
quoted by Veratti, 204
Myrosin, experiments on, 838
N
Nail, Dr., deaths from labor in caissons,
378
Names given to mountain sickness, 328
Neergaard, ascent of Maladetta, 121
Nitrogen of blood, 936
effect in sudden decompression, 881-890,
895, 1027
under increased pressure, 627-628
Nutrition, changes in compressed air, 363,
372 455, 491-492
Nysten, effect of free gases in blood, 882
injection of air into blood, 888
see also Halle and Nysten
Obesity, as factor in mountain sickness,
52, 233, 291, 326
Oliver, Capt., in Himalayas, 152
Olympus, conditions on summit of, 196
d'Orbignv, anatomv of Peruvian Indians,
301
description of mountain sickness, 37
Orizaba, ascents of, 66, 67
Ormsby, ascent of Grivola, 119
Oxide of carbon, for inflating balloon, 184
Oxygen, capacity of blood for, 641-657
at decreased pressures, 643-654; at 38°
and 40° C, 652-653
at increased pressures, 655; at 40 C,
657
toxic action of, at high tension, 565-570,
574, 578, 709-754, 1021-1024
use of, in balloon nights, 961-967, 969-
970 990-991
in decompression, 694-708, 891-894
in mountain climbing, 996-998
Oxygen content, of blood, 936-940; varia-
tions in, 940, 984-986
of various arteries, 587
under decreased pressure, 305, 981-934
under increased pressure, 622-625
of air in mines, 692-693, 984. 1007 foot-
note 7
Oxygen lack, in air as cause of mountain
sickness, 214, 218, 223, 227, 234, 235. 242,
244, 245, 252-254, 337, 338
Oxvgen tension, effects of. on plants, 782-
788, 792-796, 798
importance of, 540, 578-580, 839, 842, 849
851, 980
in geological ages, 1034
in ocean depths, 1033-1034
resistance to, in various mammals, 549
Pamir, plateau of, 129, 143, 157
Panum, Professor, respiration and circula-
tion in compressed air, 435-437
respiratory exchanges and rhythm in
compressed air, 478-481
Papin, Denis, compressed air in diving-
bell, 358
(with Huyghens) death of animals in
vacuum, 202
Parachute, first us« in a balloon, 177
made wrong-side out, 184
Paralysis, from decompression, 373, 380.
381, 385, 386, 389, 394, 395, 399, 400, 404.
406, 408, 482, 1011
from sudden decompression, 883-885
Parrot, Dr., ascent of Ararat, 126
ascent of Kasbek, 123
ascent of Mont Blanc, 92
pulse rate in Pyrenees, 122
Pasteur, classification of fermentations, 799
Pasteurization, 830
research on microscopic organisms, 1023
verification of his experiments, 812
Payerne, cause of weariness at high alti-
tudes, 240
submarine hydrostat, 357
Pepsin, experiments on. 837-838
Perspiration, increase of, in compressed
air, 360, 376
Petard, Dr., in ascent organized by Society
of Aerial Navigation, 192
Physical constitution, as factor in moun-
tain sickness, 319-320
Index
1053
Piachaud, Dr., ascent of Mont Blanc, 108
causes of symptoms of mountain sick-
ness, 284 „ .... _,
Pissis, A., letter on effects of altitude, 56
Pitschner, ascent of Mont Blanc, 107
Plants, at low oxygen tension, 1006
as alleged cause of mountain sickness,
135. 152, 153, 221, 222, 223
artemisia, 295; flowers, 134; moss, 148-
152, 294; onion, 295; primroses, poly-
anthus, heather, 132; rhubarb. 129
Pneumatic pump, early experiments with,
197
invention of, 196
Poeppig, Ed., denial of effect of decreased
pressure, 226
symptoms of puna at Cerro de Pasco, 38
Poiseuille, effect of pressure changes on
circulation, 445-446
Pol and Watelle, symptoms of laborers in
compressed air, 362-367; cause of, 450-453
Polar Star, ascension of, 961-962
Polo, Marco, on plateau of Pamir, 128
Popocatepetl, ascent by Laverriere, 63;
by Scientific Committee of Mexican Ex-
pedition. 65; by Virlet d'Aoust, 309; va-
rious ascents, 61
Pravaz, Dr. Ch., discussion of compressed
air, use in surgery, 1029; use in thera-
peutics, 239, 415; underlying causes of
benefist from, 447-450
Pravaz, J., effects of moderate increased
pressure, 1014-1017
Prevention of mountain sickness, 996-998
Priestley, first to breathe oxygen, 1027
theory of mountain sickness, 214
Przevalski, Capt., denial of Pere Hue's
theory of mountain sickness, 238
Psychological factors in mountain sickness,
distraction of attention, 43, 142, 150, 288-
289, 292, 957
fear, 92
Pulmonary tuberculosis, "height cure" for,
960, 1006
on Pacific coast (Andes), 255
"Pundits," The, in Himalayas, 155
Putrefaction, experiments on, 800-820
effect of high oxygen tension on, 926
Pyrenees, ascents in, 120-123
individual peaks, 9
Rabbits, experiments on, diminished pres-
sure, 198; temperature and oxygen con-
sumption, 219
Radde, ascent in Armenia, 127; ascent of
Elbrouz, 124
Rameau, Professor, see Bucquoy
Ramond, ascent of Mont Perdu, 121
Rebmann, reference to Kilimandjaro, 161
Recompression, to relieve symptoms of
decompression, 894-895, 1032
Rectal temperature, in mountain ascent,
959
Regnauld, report of caisson explosion, 371
Remedies of natives for mountain sick-
ness, 34, 47, 49, 55; apricots. 145, 157:
dry fruit, 156, 157; garlic, 34, 47, 49, 50.
55; plums, 157
Remy, J., ascent of Pichincha and Chim-
borazo, 58
Research, Bert's plan of, 505-506, rejection
of unnecessary refinements in, 512
Respiration, in carbon dioxide poisoning,
920-921
in compressed air, 360, 490
amplitude, 395
capacity, 372, 374, 376, 395
rate, 372, 388, 395, 396
rhythm, 396, 454
in rarefied air
in the Engadine, 297
in Thibet, 295
on Mexican plateaux, 261-262, 265, 269
Vivenot's experiments, 280-281
Respiratory difficulties from decompres-
sion, 363, 366
Rey, Dr., explanation of mountain sick-
ness, 231
Riche, ascent of Peak of Teneriffe, 75
Riedesel, ascent of Etna, 70
Risler and Schutzenberger, release of oxy-
gen of blood, 658
Robert, balloon ascension with Charles, 171
Robertson, ascension from Hamburg, 175
second ascension, 179
comments on report of Biot and Gay-
Lussac, 180
details of symptoms in Hamburg ascen-
sion, 183
Robertson, Capt., ascent of Sumeru-Par-
but, 147 .
Robertson, Eugene, ascension from Mexico,
183
ascension from New York, 183
Rockv Mountains, individual peaks, 14
Rostan, blood gases in symptoms of de-
compression, 225
Roulin, observations on pulse rate on
mountains, 224
du Rozier, Pilatre, first aeronaut, 171
Russell, Count Henry, discussion of moun-
tain sickness, 119
Russell-Killough, Count, effect of snow in
mountain sickness, 294
reports of ascents of Nethou, 122
s
de Saint-Cricq, attack of soroche, 49
Saint-Lager, see Hervier
Saint-Pierre, see Estor and Saint-Pierre
Saliva, experiments on, 835-837
Sampadarios. Dr., pathological observa-
tions on divers, 405-410
Sandahl, Dr., physiological effects of com-
pressed air, 416
theory of effects, 466-467
de Saussure, ascent of Buet, 79; of Mont
Blanc, 80; of Mont Cenis, 85
discussion of cause of mountain sickness,
213 . ,
exceptional symptoms of mountain sick-
ness, 251
experiment on oxygen content of snow,
227
observation of variations of magnetic
power, 179
physiological observations on the Col du
Geant, 86
refutation of theory of Bouguer, 216
theory of fatigue in mountain sickness,
347
de Sayve, A., ascent of Etna, 72
Schlagintweit brothers, summary of their
highest ascents, 154-155
Schmidtmeyer, on Pass of Cumbre, 35
Schutzenberger, see Risler
Scorpion's venom, experiments on, 845-846
Scoutetten, effect of altitude on physio-
logical functions, 276
Secretions, changes in, in compressed air.
360, 397, 455, 491, 1011
Seeds, Bert's experiments on, at high car-
bon dioxide tension, 925-926
at high oxygen tension, 784-785, 793-796
at low oxygen tension, 784, 792
germination under decreased pressure,
782-783, 786
germination under increased pressure,
443, 789-791
Beale's experiment on lettuce seeds, 203
Boyle's suggestion of experiment, 203
Semenof, mountain sickness in Celestial
Mountains, 153
Sensitive plants, as a "reagent," 781
effect of pressure on.
1054
Index
decreased, experiments, 787-788.
Boyle's suggestion of experiment, 203
increased, 797
Sensitivity, loss of, from decompression,
372, 402, 406
"Sheep" (moutons), 377; explanation of.
886
Sherwill, Capt, ascent of Mont Blanc, 91
Shifts, length of, in compressed air, 362,
372, 377, 386, 388, 389, 394, 487, 493
Sievers, ascent in Armenia, 127
Silkworm cocoons, Bert's experiments on.
684-685, 752, 776; Boyle's suggestion of
experiment on, 203
Simonoff, Dr. Leonid, medical effects of
compressed air, 1020
Simons, balloon ascension with the "Flying
Man," 193
Sivel, balloon ascension in Polar Star, 961-
962
effects of rarefied air on, 673
experience in decompression chamber,
700-703
fatal ascension in Zenith, 963-969
funeral eulogy of, 971-974
in ascension organized by Society of
Aerial Navigation, 192-193
Sjogrun, ascent of Kasbek, 124
Smell, sense of, weakened in compressed
air, 375, 492
Smith, Dr. Archibald, notes on mountain
sickness in Peru, 44
symptoms and causes of mountain sick-
ness, 233
Smyth, mountain sickness, 44
Snow, as cause of mountain sickness, 226,
294, 338
line of perpetual snow in relation to
mountain sickness, 318
Soldan, Mateo Paz, description of soroche.
53
Spalding, improvements in diving-bell, 355
Spallanzani, ascent of Etna, 71
Speer, nature and causes of mountain
sickness, 241
Spitaler, ascent of Venediger, 97
Stoliczka, Dr., fatal attack on Karakorum,
974-976
Strobel, Pellegrino, free from effects of
soroche, 55
Studer, Gottlieb, ascent of the Jungfrau,
97
Steubel, ascent of Cotopaxi, 59
Sturmius, invention of diving-bell, 355
Submarines, early types of, 357-358
Symptoms, due to decompression, 540, 983
cerebral disturbances, 363-366, 372-373,
377, 379, 381, 402, 406, 492; theories
about, 457, 465, 466
circulation, 669-672
digestion, 672-673
lower pressure limit of appearance of.
685
means of averting, 694-708
nervous and muscular effects, 673-675
nutrition, 675-685; body temperature,
683-684; development, 684-685; respira-
tory exchanges, 675-678; sugar in liver,
blood, and urine, 681; urinary excre-
tion, 678-681
post mortem; rigor mortis, 688; shown
at autopsy, 687-688
respiration, 666-669
Symptoms, of mountain sickness, 241-242
circulation, 329-331
digestion, 328
innervation, 332-333
locomotion and exertion, 331-332
secretions, 329
Symptoms, of oxygen poisoning
blood sugar, 749
convulsions, 740-743
diminution of oxidations, 743
excretion of urea, 748-749
pulmonary exchanges, 744-748
Tabariti, Dr., therapeutic effects of com-
pressed air, 415
Tardieu, physiological effects of rarefied
air, 270
Taste, sense of, weakened in compressed
air, 375, 492
Temple, Ed., soroche at Potosi, 36
Teneriffe, Peak of, ascents of, 73-77
mountain sickness on, 196
Testu-Brissy, balloon ascension with
horse, 173
Therapeutics, use of diminished pressure
in, 220, 228, 1007
use of increased pressure in, 239, 1005
Thomas, Prof. L., effect of ascent on body
temperature, 959
Thomson, R. F., ascent of Demavend, 128
Thomson, Taylor, ascent of Demavend, 123
Thomson, Dr. Th., passes of Parang and
Karakorum, 145
Thoracic capacity, see chest capacity
Thorpe, buccal temperature in ascent, 957
Time of appearance of symptoms due to
decompression, 361-364, 493, 1011
Tissandier, Albert, ascent of Mont Blanc.
115
Tissandier, Gaston, report of ascension of
Zenith with Sivel and Croce-Spinelli,
963-969
Tissues, experiments on,
carbon dioxide accumulation in, 911-913
lethal concentration of carbon dioxide
in, 914
putrefaction of, in high carbon dioxide
tension, 926-927
Torrente, symptoms and cause of moun-
tain sickness, 33
Torricelli, early experiments of, 197
invention of barometer, 196
de la Touanne, discussion of mountain
sickness, 36
Tournefort, ascent of Ararat, 126
Training, effect of lack of, in mountain
sickness. 292, 293, 294, 324-325, 327
result of, in mountain climbing, 956, 996
Triger, invention of industrial compressed
air apparatus, 358
memoir on caisson accidents, 384
physiological effects of compressed air,
359-360
Trouessart, report on Triger apparatus, 359
von Tschudi, J. J., explanation of weari-
ness of legs in ascent, 232
description of the Vela, 45
Truqui, ascent of Popocatepetl, 63
Tuckett, ascent of Grivola, 116
Turner, Samuel, in Thibet, 130
Tutschek, physiological effects of com-
pressed air, 417 .
theory of action of compressed air, 467
Tyndall, first ascent of Mont Blanc, 106
second ascent, 107
importance of food in ascents, 293
u
Ulloa, discussion of cause of mountain
sickness, 209
symptoms caused by mountain air, 210
symptoms of the Mareo, 28
Urbain, see Mathieu
Urea, production of, in compressed air
(1 to 5 arm.), 748-749, 764-765
in rarefied air, 983
effect of diet on, 1025
thesis of Pravaz on, 1015-1016
Urination, effect of decompression on, 373,
380, 387, 389, 399, 401, 406
Urine, Bert's experiments on, 823-825
carbon dioxide content of, 914
secretion of, in compressed air, 364, 385,
Index
1055
d'Urville, Dumont, ascent of Peak of Ten-
eriffe, 75
Vaccine virus, Bert's experiments on, 846
Vacher, Dr., effect of moderate altitude on
pulse and respiration, 960-961
Valentin, unimportance of changes in
pressure, 244
Van Rensselaer, ascent of Mont Blanc, 89
Venom, scorpion's, Bert's experiments on,
845-846
Veratti, experiments of, 204
study of asphyxia in closed vessels, 205
Vibriones, tenacity of life in, 1035
Vierordt, effect of decompression on res-
piration, 236
Vincent, ascent of Monte Rosa, 93
Viruses, Bert's experiments on, 846-848
Anthrax, 847-848
Glanders, 847
Vaccine, 846-847
Visconti, ascent of Monte Rosa, 117
"Vital force," 444
von Vivenot, Rudolph, research on circu-
lation and respiration
circulation in compressed air, 423-432
experiment on circulation, 474-475
respiration in compressed air, 418-423
respiration in rarefied air, 280
respiratory exchanges in compressed air,
467-474
summary of physiological effects in com-
pressed air, 432-435
Vogt, A., effect of altitude on respiration.
237
Voice, changes in, under increased pres-
sure, 359-361, 370, 375. 387, 490
w
Wafer, on the Isthmus of Darien, 59
Ward, Dr., acclimatization in high alti-
tudes, 960
Watelle, see Pol
Webb, Capt., experiences in Himalayas, 134
Weddell, ascent of Arequipa, 48
soroche in La Paz, 50
Weight of air sustained by body, decrease
of, in rarefied air, 276, 340-342
increase of, in compressed air, 453, 494
Welsh, J., balloon ascension for scientific
purposes, 186
Whistling, in compressed air, 359-362, 375,
490
in rarefied air, 698-699, 704-707
Wilkes, ascents of Mauna Loa, Hawaii. 164
Williamson, ascent of Mount Hood, Ore-
gon, 69
Wind, effect of, in mountain sickness, 335
Wine, Bert's experiments on, 827-831
Wisse, on Rucu-Pichincha, 57
Women mountain climbers, 75, 88, 96, 115,
122, 147
Wood, Lieut. J., on plateau of Pamir, 143
Yaks, effect of high altitude on, 134
Yeast, brewers, Bert's experiments on, 826
inversive ferment of, experiments on.
Zambeccari, Count Fr., balloon ascension
at Bologna, 178
Zenith, ascension of, 963-971
Zumstein, ascent of Monte Rosa, 93
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