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»U^ 



PHYSIOLOGICAL R£S£AECHËS 



j' 



ON 



LIFE AND DEATH, 



BY XAVIER BICHAT; 

I 



^x^xmXtit^ from tlir if rrticfi. 



BY F. GOLD, 

MEMBER OF THE ROYAL COLLEGE OF SURGEONS, LONDON : 

WITH NOTES, 

BY F. MAGENDIE, 

Member of the Institute and of tlie Royal Academy of Medicino. 



THE. JVOTES TRJlJfSUtTED 

BY GEORGE HAYWABD, M. D. 



fT BOSTON : 

'^ PUBLISHED BY RICHARDSON AND LORD. 

J. H. A. FROST, PRINTER. 

1827. 



ti'" 






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4 ^ 



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\«« ■»^VJV<\ ^ 



THE NEW YORK 

POBUC LIBRARY 

482390A 

ASTOR. LEHOX AND 
TILDEN FO'JN DATiO.>«fc^ j 

a 103O L I 



DISTRICT OF MASSACHUSETTS : to uU. 

Dùtnet ClerkU Office, 

BE IT REMEMBERED, That on the KveiiteenUi day of December, A. D. 18S7, in the 
ifW'-eecond vear of the IndependeiK» of the United States of America, RICHARDSON 
it LORD, of the said District, have deposited in this otfice the title of a book, the rif ht 
whereof they elatiu as proprietors, in the words following, to vit : 

" Physiolojncal Researches on Life and Death, by Xavier Bichat ; translated from the 
Fimich, by F. Grold, member of the Royal Collège of Surgeons, London, with notes, by 
F. Mag'3ndie, member of the Institute and of the Royal Academy of Medicine. The notes 
traoalated by George Hayward, M. D.'* 

In conformity to the Act of the Congress of the United States, entitled, " An Act for 
the encoaragement of Learning, by securing the copies of Maps, Charts and Books, to the 
Anthors and Pioprietors of such Copies, during the tiroes therein mentioned :'* and also to 
an Act entitled, '* An Act suppiemeotary to an Act, entitled. An Act for the encouragement 
of Learomg, by securing the Copies of Maps, Charts and Books, to the Authors ami Pro- 
prietors of such Comes during the times therein mentioned; and extending the benefits 
thereof to the Arts « Designing, Engraving and Etching Historical and other PrinU/' 

JOHN W. DAVIS, 
Clerk of tke District of Maosadkuoettg. 



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TRANSLATOR'S PREFACE. 



THE Translator of the Work which is here offered to the 
Public, feels it quite unnecessary to expatiate upon the merits 
of its Author, whose ideas and classifications in Physiology are 
now very generally adopted. He has supposed, however, that 
the experiments which constitute the Second Part of the Work, 
are not so familiar to Professional Men, as many of the conclu- 
sions which have been deduced from them, and therefore has 
presumed that a greater publicity of these experiments will 
by no means be unserviceable. Dr. Kentish, in his account 
of Baths, has mentioned the circumstances which led to this 
translation. 



/■I 



ADVERTISEMENT BY THE FRENCH EDITOR. 



THE work of Bichat, which appears to the most 
advantage, is the one that we now reprint ; his observing 
mind, his experimental genius and his lucid manner of 
exhibiting facts are particularly observable in it. This 
work will have for a very long time a great influence oa 
physiologists and physicians. 

The Physiological Researches on Life and Death have 
had more than one class of admirers. Exact minds, friends 
of the progress of science have praised it for the great 
number of accurate observations which it contains, the 
ingenious management of the experiments and the correct- 
ness of the deductions ; but they have regretted that the 
author constantly placed life in opposition to physical laws^ * 
as if living beings were not bodies before they "were vege- 
tables or animals. They have seen with regret that he 
offered illusory explanations of inexplicable phenomena. 

These grounds of legitimate criticism seem to have 
been the reason of the enthusiasm of another cla«s of 
readers, for whom whatever is vague appears to have a . ' 
great degree of attraction. The readers, of whom I have 
just spoken, feeling but little interest in the new facts 
which the Physiological Researches contain, have adopted 
without examination its fallacious hypotheses, and attach- 
ing to them an importance which the author never did, 
because they believed that they elucidated the mechanism 



^»-,. 



ot the moat obscure Tiul opera cIoqs, and eooducted to a 
tnie theory ot medicine. Should we lament this erroar? 
Certainly no^ as it has powertnlly coarhbuted to the 
brilliant «iicceas oe Bichat'4 work* and bv means of some 
crrours, much tmtn has been promulgated. 

\% the works ot' Bichat have now become classics and 
their reputation cannot be increased, it is time to place 
younjc students on their ^nard against the errours into 
which the imagination of the author led him, and which 
are the more to be tcared, as Bichat in order to coarince, 
has employed all the tascinatioas of his aaimated style. 

The memory of Bichat cannot but ^n by it : the 
aamerous truths which he has discovered will shine with 
a fari;çhter lights when freed from, the li^t shades that 
envelope them. 

Such is the object of the notes to the present edition, 
which we have eadeaTOiucd to bring up to the prcae&t 
state of kaowledge. 



CONTENTS OF THE WORK. 



CHAPTER I. 

Pag« 
DivinoB of Life into Animal and Oiganic Life ... 11 

CHAPTER II. 

General Difièrences of the two Lives, with regard to the outward form of their respec- 
tive Organs 18 

CHAPTER III. 

Qeneral Differences of the two Lives, with regard to the mode of action of their 
respective Organs SS 

CHAPTER IV. 

Oeneral Differences id the two Lives with respect to Doratiom of Actk» t- , - f^ 

CHAPTER V. 

GeneralDifferenoeioftiie two Lives with respect to Habit 46 

CHAPTER VI. 

Cteeral Difbreaoes of the two Lives with respect to Mental Affection 54 

CHAPTER VII. 

General Differences of the two Lives with respect to Vital Power .... 78 

CHAPTER VIII. 

Of the Origin and Develo{»nent of the Animal Life ...... 13S 

CHAPTER IX. 

Of the Origin and Development of the Organic Life ...... 156 

CHAPTER X. 

Of the Natoial Termination of the Two Livia lA 



ij 



• •• 



VUi CONTENTS. 

FABT TBB SBOOND. 

CHAPTER I. 

General Coiuiderationt on Death Ï73 

CHAPTER II. 

or the Influence of the Death of the Heart over that of the Brain 176 

CHAPTER III. 

Of the Influenae of the Death of the HMirtov«r that of the Lunga 193 

CHAPTER IV. 

Of the Influence of the Death of the Heart over that of all the Orfani 194 

CHAPTER V. 

Of the Influence of the Detlli of the Heart, aa to tbt prodnetion of Oeneral Death 908 

CHAPTER VI. 

Of the Influence of the Death of thaLviti over that of the Heart ... SIO 

CHAPTER VII. 

Of the Inflaence of the Death of the Lang* over that of the Brain 837 

CHAPTER VIII. 

Of the Inflnenee of tha Death of the Lungi over that of the Orfana in general . 858 

CHAPTER IX. 

Of the Inflaenoe of the Death of the Lunga over the Oeneral Death of the Body . 870 

CHAPTER X. 

Of the Influence of the Death of the Braia over tfiat of the Lunga ... 897 

CHAPTER XI. 

Of the Influence of the Death of the Brain over that of the Heart .... 905 

CHAPTER XII. 

Of the Influence of the Death of the Brain over that of all the Organa . . 318 

CHAPTER XIII. 

Of the Influence of the Death of the Brain over that of tiie Body in General . 338 



PHYSIOLOGICAL RESEARCHES 



on 



LIFE AND DEATH. 



CHAPTER I. 



GENERAL DIVISION OF LIFE.* 

THE deûnition of life is usually sought for in abstract 
considerations ; it will be found^ if I mistake not, in the 

* The fora adopted bj Bicbat, in ibis work, bas been mucb blamed 
bj some, and extravagantly praised by others. The blame and the 
praise appear to me to be eqaallj misplaced. Ilis object was to exhibit 
the yarious phenomena of life ; the order in which this was to be done 
was a patter of indifference. If Bichat gave a preference to this form, 
it was because it was conformable to the nature of his mind ; and be 
accomplished his task in a very happj manner. The division that 
he has adopted is not new, it maj be found, with slight modifications, 
in writeri» of different periods, and even in Aristotle Besides, it is not 
necessary in the sciences to attach a very great importance to classifica- 
iion. All these contrivances have been invented only to aid the 
memory ; and the functions of living bodies are not so numerous, as to 
render it necessary in studying them to lean upon systematic divisions. 

2 






■i . 



1, 



10 PFIYSIOLOGICAL RESEARCHES 

following general expression : — Life consists in the sum 
of the functions, by which death is resisted.* 

In living bodies, such in fact is the mode of existence, 
that whatever surrounds them, tends to their destruction. 
They are influenced incessantly by inorganic bodies; they 
exercise themselves, the one upon the other, as constant 
an action; under such circumstanc'es they could not long 
subsist, were they not possessed in themselves of a perma- 
nent principle of reaction. This principle is that of life; 
unknown in its nature, it can be only appreciated by its 

^TIm word lift has been em|>loyed bjr physiologists in two different 
-senses. With tome, it means an iniagiuarj being, the sole principle of 
all the functions which living bodies exhibit ; with others, It means 
•nlj the assemblage of these functions. It is in this last sense that 
Bichat employs it. This ii what he mans to say in the -following 
aentence. lAft is the (usembUige of ike functions which resist deathm 
He is wrong only in allowiD|^ the idea of death to enter into it ; for this 
idea necessarily supposes that of life. There is then really a bad circle 
in this definition t but in putting iiide what is defective in the expres- 
■ioD, it may be seen that Bichat considers life as a result, not as a cause. 

Before and since the time of Bichat, a great number of definitions of 
life has been given, which are either false or incomplete. It should not 
be required of a definition, that it should give all the properties of the 
thing which it is designed to make known, this would be a description ; 
but we have a right to expect that it should assign to this thing certain 
characters which belong to it alone, and thus distinguish it from every 
thing else. 

Let us examine by this principle the definition adopted in a modern 
work. Xft/e, it is said, is the assemblage of the phenomena which 
succeed each other^ for a limited time^ in an organized being. This is 
no doubt true of life ; but, if it can also be applied to another state, 
it ceases to be a definition. An animal has just died ; its organs from 
that moment are subject to the action of chemical affinities only; 
decomposition takes place, gases are disengaged, fluids flow out and 
new solid aggregates are formed. After a time every molecular motion 
ceases ; there remains only a certain number of binary, ternary combi- 
nations, &c. Here then is an assemblage of phenomena taking place for 
a limited time in an organized body^ and yet it is not lifet 



ON LIFE AND DEATH. 1 1 

phenomena: an habitual alternation of action and reactioti 
between exterior bodies, and the living body, an alterna- 
tion, of which the proportions vary according to the age 
of the latter, is the most general of these phenomena. 

There is a superabundance of life in the child: In the 
child, the reaction of the system is superior to the action, 
which is made upon it from without. In the adult, 
action and reaction are on a balance ; the turgescence of - 
life is gone. In the old man, the reaction of the inward 
principle is lessened, the action from without remaining 
unaltered ; it is then that life . languishes, and insensibly 
advances towards its natural term, which ensues when all 
proportion ceases. 

The measure, then, of life in general, is the difference 
which exists between the effort of exterior power, and 
that of interior resistance. The excess of the former is 
an indication of its weakness % the predominance of the 
latter an index of its force. 



I. Division of Life info •animal and Organic Lift.* 

Such is life considered in the aggregate ; examined 
more in detail it offers us two remarkable modifications, 
the one common to the vegetable and the animal; the 

*Thi8 disfinction of the two lives is bad, inasmuch as it tends to 
separate phenomena which have a very intimate connexion, which 
relate to a common object, and which are often produced by means in 
every respect similar. Why should I rank among the organs of animal 
life the muscular apparatus which carries the alimentary mass from the 
mouth into the oesophagus, and among those of the other life, that 
which takes it from the cardiac orifice to the anus ? Is not the action 
of the first apparatus in relation with nutrition as well as the action of 
the last, and does not the muscular apparatus of the oesophagus act 
upon a body which is foreign to us, as well as that of the tongue and the 
pharynx ? Do the motions of mastication differ in their object fron 



i 



12 PHYSIOI^OGICAL RESEARCHES 

other belonging exclusively to the latter. In comparing 
two individuals from each of the living kingdoms, the 
one will be seen existing only within itself, having with 
what surrounds it the relations only of nutrition, attached 
to the soil, in which its seed has been implanted, born 
there, growing there, and perishing there. The other 
will be observed combining with this interior life, which 
in the highest degree it enjoys, an exterior life by which 
it acquires a very numerous series of relations with all 
surrounding bodies, a life, which couples it to the exis- 
tence of every other being, by which it is approximated, 
or removed from the objects of its desires or its fears, 
and seems in appropriating every thing in nature to itself, 
to consider every thing with regard to its individual 
existence only.'*' 

those of which we have just spoken, and as to the means of execution, 
does not the muscular action still perform the principal part ? 

We might in the same way bring near each other the motions by 
means of which we seize our food. The action itself of the senses, 
which directs these motions, is, with nutrition, in a relation more 
remote, but not less necessary, and we see in the various classes of 
animals that their apparatus is modified according to the different kinds 
of nourishment. If the distinction of the two lives be wanting in 
justice, as to the object of the functions it separates, we shall soon see 
that the characters attached to the organs of one and the other do not 
establish this division in a more striking manner. 

* This division between vegetables and animals is far from being so 
striking as is here supposed ; these two classes of beings, so different 
when we examine them in the individuals endowed with a very com- 
plicated organization, approximate each other in a remarkable degree, 
when we descend to those species whose structure is most simple ; it is 
even remarkable that the most constant character which distinguishes 
ene from the other, is not found in the organs of animal life, but in those 
of vegetable or organic life. The senses are one after the other found 
wanting ; for in an individual in whom we can discover no nervous 
system, there is no more reason to suppose the existence of the sense 
•f touch as a sensation, than to suppose it in the sensitive plant, the 



OH LIFE AND DEATH. 13 

Thus it might be said, that the vegetable is only the 
sketch; or rather the ground-work of the animal ; that 
for the formation of the latter, it has only been requisite 
to clothe the former with an apparatus of external organs, 
by which it might be connected with external objects. 

From hence it follows, that the functions of the animal 
are of two very different classes. By the one (which is 
composed of an habitual succession of assimilation and 
excretion) it lives within, itself, transforms into its 
proper substance the particles of other bodies, and after- 
wards rejects them when they are become heteroge- 
neous to its nature. By the other, it lives externally, 
is the inhabitant of the world, and not as the vegetable 
of a spot only; it feels, it perceives, it reflects on its 
sensations, it moves according to their influence, and 

dioDsea mnscipula, and other similar plants ; we see onlj action and 
reaction. The motions of the arms of certain polypi no more suppose 
Yolition than the motion of the root which follows a wet sponge» or that 
of the branches which tarn towards the light ; the onlj yeiy constant 
character is the absence or presence of a digestive cavitj. To speak 
of an animal as a vegetable clothed with an external apparatus of organs 
of relation, is a more brilliant than profoand view of the subjeet* 
Boisson, who, in his division of the phjsiological phenomena, avoids th» 
inaocoracj, has himself fallen Into error ; he pretends that respiration 
belongs ezolnsivelj to animals ; and that thus the division of Bicbat 
was not only unfounded but also incomplete, since this function, which 
is neither of vegetation nor of relation, could be ranked under neither 
life. Bulsion wai not weU informed; no doubt the respiration of 
vegetables does not exhibit the most apparent phenomena of the 
respiration of the maunmalia, but every thing, which essentially con- 
stitutes the function, is found in the one as well as in the other ; 
absorption of the atmospheric air, and the formation and exhalation of 
a new gas ; the rest is only accidental and is not an appendage but in 
certain classes of animals. In some reptiles, though we find a particular 
organ for respiration, this organ is not indispensable ; it may be removed, 
and the skin becomes the only respiratory organ ; and when finally we 
come to consider animals with irachtœ^ we see that the conformitj 
becomes more and more evident. 



14 PHYSIOLOGICAL KESEARCUES 

frequently is enabled to communicate by its voice its 
desires, and its fears, its pleasures^ and its pains. 

The aggregate of the functions of the first order, I 
shall name the organic life, because all organized beings, 
whether animal or vegetable, enjoy it more or less, 
because organic texture is the sole condition necessary to 
its existence. The sum of the functions of the second 
class, because it is exclusively the property of the animal, 
I shall denominate the animal life. 

The series of the phenomena of these two lives, relate 
to the individual. Generation, as a function, regards the 
species, and thus has no place among them. Its connec- 
tions with the greater number of the other functions are 
but very indirect ; it commences a long time after them, 
it is exlinct a long time before them. In the greater 
number of animals the periods of its activity are separated 
by long intervals of time, and during these, it is abso- 
lutely null. Even in man, with whom the remissions of 
its impulses, are much less durable, it has not a much 
more extensive connexion with the rest of the system. 
Castration is almost always marked by a general increase 
of the nutritive process ; the eunuch, enjoying indeed a 
less degree of vital energy, but the phenomena of his 
life being displayed with a greater exuberance. Wç 
shall here, then, lay aside the consideration of the laws 
which give us existence, and occupy ourselves alone on 
those which maintain us in existence. Of the former we 
shall speak hereafter. 

Ih Subdivision qf each of the two lives into two 

orders of functions. 

The animal and the organic life, are each of them 
eomposed of two orders of functions, which succeed each 
other, and are concatenated in m inverse direction. 



ON LIFE AND DEATH. 15 

In the animal life, the first order is established from 
the exterior of the body, towards the brain -, the second 
from the brain towards the organs of locomotion and 
the voice. The impression of objects successively affects 
the senses, the nerves and the brain. The first receive, 
the second transmit, the third perceives the impression. 
The impression, in such way, received^ transmitted, and 
perceived, constitutes sensation. 

The animal, in the first order of these functions, 1$ 
almost passive ; in the second, he becomes active. — This 
second order is the result of the successive actions of the 
brain (where volition has been produced in consequence 
of the previous sensation) of the nerves, which transmit 
such volition, and of the locomotive organs and voice, 
which are the agents of volition. External bodies act 
upon the animal by means of the first order of these 
functions, the animal reacts upon them by means of the 
second. 

In general there exists between the two orders a 
rigorous proportion ; where the one is very marked, the 
other is put forth with energy. In the series of living 
beings, the animal, which feels the most, moves also 
the most. The age of lively perception, is that also of 
vivacity of motion ; in sleep, where the first order is 
suspended, the second ceases, or is exercised only with 
irregularity. The blind man, who is but half alive to 
what surrounds him, moves also with a tardiness which 
would vefy soon be lost^ where his exterior communica- 
tions to be enlai^d. 

A double movement is also exercised in the organic 
life; the one composes, the other decomposes the animal. 
Such is the mode of existence in the living body, that 
what it was at one time it ceases to be at another. Its 
organization remains unaltered» but its elements vary 



1^ PHTSI0L06ICAL RESEARCHES 

every moment. The molecules of its nutrition by turns 
absorbed and rejected, from the animal pass to the plant, 
from the plant to inorganic matter, return to the animal, 
and so proceed in an endless revolution. 

To such revolution the organic life is well adapted. 
One order of its functions assimilates to the animal the 
substances which are destined to nourish him ; another 
order deprives him of these substances, when, after 
having for some time made a part of it, they are become 
heterogeneous to his organization. 

The first, which is that of assimilation, results from 
the functions of digestion, circulation, respiration, and 
nutrition. Every particle, which is foreign to the body 
before it becomes an element of it, is subject to the 
influence of these four functions. 

When it has afterwards concurred for some time to the 
formation of the oi^ns, the absorbents seize on it, and 
throw it out into the circulatory torrent, where it is 
carried on anew, and from whence it issues by the 
pulmonary or cutaneous exhalations, or by the different 
secretions by which the fluids are ejected from the body. 

The second order, then, of the functions of the organic 
life, or that of decomposition, is formed of those of absorp- 
tion, circulation, exhalation, and secretion. 

The sanguiferous system, in consequence, is a middle 
system, the centre of the organic Kfe, as the brain is the 
centre of the animal life. In this system the particles, 
which are about to be assimilated, are circulated and inter- 
mixed with those, which having been already assimilated, 
are destined to be rejected ; so that the blood itself is a 
fluid composed of two parts ; the one, the pabulum of all 
the parts of the body, and derived from the aliment ; 
the other, excrementitious, composed of the wrecks and 
residue of the organs, and the source of the exterior 



ON LIFE AND DEATH. n 

secretions and exhalations. — Nevertheless these latter 
functions serve also, at times, the purpose of transmitting 
without the body, the products of digestion, although 
such products may not have concurred to the nourish- 
ments of the parts. This circumstance may be observed 
when urine and sweat are secreted after copious drinking. 
The skin and the kidneys being at such times the excret- 
ing organs, not of the mattter of the nutritive, but of that 
of the digestive process ; the same also may be said of 
the milk of animals, for this is' a fluid which certainly has 
never been assimilated.* 

'There does not exist between the two orders of the 
functions of the organic life the same relation, which 
takes place between those of the animal life. The 
weakness of the first by no means renders absolutely 
necessary a decrease of action in the second. Hence 
proceed marasmus and leanness, states^ in which the 

* Bicbat seems here to adopt the generaUj received opinion that it it 
the chyle which famishes to the mammary gland the materials of which 
the milk is composed. We know not whence this opinion arises, if it 
be not from the gross resemblance which the chyle and milk often 
exhibit. This resemblance, if it were very great, would be a poor 
reason for admitting^ without anatomical proof, so singular a fact ; bat 
it is very far from being perfect. The chyle in fact does not exhibit 
the milky appearance and the white opake colour, only when the 
animal from whom it is taken, has fed upon substances containing fat ; 
in all other cases, it is almost transparent ; its odour and taste, under 
all circumstances, differ entirely from those of milk ; if these two ûMm 
are left to themselve?, the milk remains a long time without coagulating^ 
but the chyle almost immediately coagulates, and then leparatet into 
three parts. The solid portion soon exhibits cells, and an appearance 
of organization ; nothing similar is seen in the cogulum of milk ; the 
serum of the milk remains colourless when exposed to the simple 
contact of the air, that of the chyle assumes a rosy tint, often very 
vivid. Finally, if we examine the chemical composition of these two 
fluids, we shall find in them differences still more striking. (See for 
/arther details, my Elements of Physiology, Vol. )2d.) 

3 



1$ rHTSIOLOGlCAL RESEARCHES 

aasimilating process ceases in part^ the process of ezcre- 
tion remaining unaltered. 

Let us leave, then, to other sciences, all artificial 
method, but follow the concatenation of the phenomena 
of life, for connecting the ideas which we form of them, 
and we shall perceive, that the greater part of the present 
physiological divisions, afford us but uncertain bates for 
the support of any thing like a solid edifice of science. 

These divisions • I shall not recapitulate ; the best 
method of demonstrating their inutility will be, if I 
mistake not, to prove the solidity of the division, which 
I have adopted. We shall now examine the great differ- 
ences, which separate the animal existing without, from 
the animal existing within, and wearing itself away in a 
continual vicissitude of assimilation and excretion. 



CHAPTER IL 

GENERAL DIFFERENCES OF THE TWO LIVES WITH REGARD 
TO THE OUTWARD^ FORM OF THEIR RESPECTIVE 

ORGANS. 

The organs of the animal life are symmetrical, those 
of the organic life irregular in their conformation; in 
this circumstance consists the most essential of their 
differences. Such character, however, to some animals, 
and among the fish, to the sole and turbot especially, is 
not applicable ; but in man it is exactly traced, as well as 
in all the genera which are nearest to him in perfection. 
ïn them alone am I about to examine it. 



i 

I 



ON LIFE AND DEATH. 19 



I. Symmetry of the external form^ cf the animal l\fe.^ 

Two globes ID every respect the same, receive the 
impressions of light. Sounds and odours, have also their 
double analogous organ. . A single membrane is affected 
to savours, but the median line is manifest upon it, and 
the two segments, which are indicated by it, are é^ctly 
similar. This line indeed is not every where to be seen 
in the skin, but it is every where implied. Nature, as it 
were, has forgotten to describe it, but from space to space 
she has laid down a number of points, which mark its 
passage. The cleft at the extremity of the nose, of the 
chin, and the middle of the lips, the umbilicus, (he seam 
of the perineum, the projection of the spinous apophyses 
of the back, and the hollow at the posterior part of the 
neck are the principal points at which it is shewn. 

The Nerves, which transmit the impressions received 
by the senses, are evidently assembled in symmetrical 
pairs. 

^It is rather to the external forms that symmetry appears to hare 
been primitively attached, and it is in some measure accidentally and 
because the nature of their functions requires in general that they 
should be placed on the exterior, that the organs of relation are found 
modified in virtue of this law. In the example cited, of fishes without 
a bladder, the eyes, to lose nothing of their utility, must be differently 
placed, and on the face, which alone is in relation with the light ; yet 
even in this case, the symmetry of external forms has been displaced 
rather than destroyed, and at the first examination it seems complete* 
When the organs of relation are found placed on the interior, they 
frequently exhibit some irregularity, and to take an example of a known 
animal, the organ of voice, in the male duck, is a very remarkable one ; 
in man even, the wind-pipe is not symmetrical, after it arrives at the first 
division of the bronchia. On the contrary, among tJie organs of the 
other life, those which are promment on the exterior, constantly 
present the synunetricai character, as the thyroid gland, the aanunary 
glands, &c. 



to PHYSIOLOOICAL RESEARCHES 

The brain, the organ (on which the impressions of 
objects are received) is remarkable also for the regularity 
of its form. Its double parts are exactly alike, and even 
those which are single, are all of them symmetrically 
divided by the median line. 

The Nerves again, which transmit to the agents o*f 
loco-motion and of the voice, the volitions of the brain, 
the locomotive organs also, which are formed in a great 
degree of the muscular system, of the bony system» and 
its dependencies, these together with the larynx and its 
accessaries, composing the double agents of volition, 
have all of them a regularity, a symmetry, which are 
invariable. 

Such even is the truth of the character which I am now 
describing, that the muscles and the nerves immediately 
cease to be regular, as soon as they cease to appertain to 
the animal life. The heart, and the muscular fibres of 
the intestines are proofs of this assertion in the muscles ; 
in the nerves, the great sympathetic, is an evidence of its 
truth. 

We may conclude then from simple inspection, that 
Symmetry is the essential character of the organs of the 
animal life of man. 

IL Irregularity of the exterior forms of the organic 

life. 

If at present we pass to the viscera of the organic life^ 
we shall perceive a character directly the contrary of the 
former. The stomach, the intestines, the spleen, the 
liver, &c. are all of them irregularly disposed. 

In the system of the circulation, the heart and the large 
vessels, such as the upper divisions of the aorta, the vena 
azygos^ the vena ports, and the arteria innominata have 



ON LIFE AND DEATH. 21 

no one trace of symmetiy. In the vessels of the extremi- 
ties continual varieties are also observed, and when they 
occur, it is particularly remarkable that their existence 
on one side in no way affects the other side of the body. 

The apparatus of respiration appears indeed at first to be 
exactly regular ; nevertheless, the bronchi are dissimilar 
in lengthy diameter, and direction ; three lobes compose 
one of the lungs, two the other : between these organs 
also, there is a manifest difference of volume ; the two 
divisions of the pulmonary artery resemble each other 
neither in their course, nor in their diameter ; and the 
mediastinum is sensibly directed to the left. We shall 
thus perceive that symmetry is here apparent only, and 
that the common law has no exception. 

The organs of exhalation and absorption, the serous 
membranes, the thoracic duct, the great right lymphatic , 
vessel, and the secondary absorbents of all the parts have 
a distribution universally unequal and irregular. 

In the glandular system also we see. the cr3rpt8, or 
mucous follicles disseminated in a disorderly manner in 
every part ^ the pancreas, the liver, the salivary glands 
themselves, though at first sight more symmetrical, are 
not exactly submitted to the median line ; added to this, 
the kidneys differ from each other in their situation, in 
the length and size of their artery and vein, and in their 
frequent vaùrietiet more especially.* 

* ir we deny sjmmetiy to the kidncyi, became tbej are not unifonD] j 
composed of the tame number of lobes m children, we most deny it 
also to the brain, the two lobes of which never exhibit the same 
arrangement in their circumYolotioDt | if we deny it to the salivary 
glands, because one is larger than the other, we must deny it to the 
extremities, because the right li usually awro developed than the left. 
If these examples are not enough, a hoit of othen might be oited ; such 
as, the atrabiliary capsules, the bladder, the différent organs of fsncn- 
tion and lactation, and the very Kgolar amogeaent of tba Mwons 



j92 PHYSIOLOOICAL RESEARCHES 

From considerations so numerous we are led to a result 
exactly the reverse of the preceding one ; namely, that 
the especial attribute of the organs of the interior life is 
irregularity of exterior form. 

III. Consequences resulting from the difference of 
exterior form in the organs of the two lives. 

It follows from the preceding description, that the 
animal life is as it were double ; that its phenomena 
performed as they are at the same time on the two sides 
of the body, compose a system in each of them inde- 
pendent of the opposite system ; that there is a life to 
the right, a life to the left ; that the one may exist, the 
other ceasing to do so, and that they are doubtless 
intended reciprocally to supply the place of each other. 

The latter circumstance we may frequently observe in 
those morbid affections so common, where the animal 
sensibility and mobility are enfeebled, or annihilated on 
one sidle of the body, and capable of no affection what* 
ever ; where the man on one side is little more than the 
vegetable, while on the other he preserves his claim to 
the animal character. Undoubtedly those partial palsies, 
in which the median line, is the limit where the faculties 
of sensation and motion finish, and the origin froni 
whence they begin can never be remarked so invariably 
in animals, which, like the oyster, have an irregular 
exterior. 

On thé contrary the organic life is a single system, in 
which every thing is connected and concatenated ; where 

follicles in certain parts situated apon the median line, &c. As to the 
anomalies that are obserred in the distribution of tJie blood-vessels, the j 
are also obienred very frequenUj, though in a lest eyident manner, in 
the diftribotian of the nerrout branches. 



ON LIF£ AND DEATH. 2Z 

the functions on one side cannot be interrupted^ and those 
en the other subsist. A diseased liver influences the state 
of the stomach ; if the colon on one side cease to act, that 
upon the other side cannot continue in action : the same 
attack, which arrests the circulation in the right side of 
the heart, will annihilate it also in the left side of the 
heart. Hence it follows, the internal organs on one side' 
being supposed to suspend their functions, that those on 
the other must remain inactive, and death ensue. 

This assertion, however, is a general one ; it is only 
applicable to the sum of the organic life, and not to its 
isolated phenomena. Some of them in fact are double, 
and their place may be supplied — the kidneys and lungs 
are of this description. 

I shall not enquire into the cause of this remarkable 
difierence, which in man, and those animals which 
approach him the nearest, distinguishes tlie organs of the 
two lives. I shall only observe, that it enters essentially 
into the nature of their phenomena, and that the perfec- 
tion of the animal functions is so connected with the 
general symmetry observed in their respective organs, 
that every thing which troubles such symmetry, will 
more or less impair the functions. 

It is from thence, no doubt, that proceeds this other 
difference of the two lives, namely, that nature very 
rarely varies the usual conformation of the organs of the 
animal life. Grimaud has made thb observation, but has 
AOt shewn the principle on which it depends. ...^ 

It is a fact, which cannot have escaped any one the 
least accustomed to dissection, that the spleen, the liver, 
the stomach, the kidneys, the salivary glands, and others 
of the internal life, are frequently various in form, size, 
position, and direction. Such in the vascular system are 
these varieties, that scarcely will any two salgects be 



24 PHYSIOLOGICAL RESEARCHE* 

found exactly alike under the scalpel of the anatomist : 
the organs of absorption, the lymphatic glands in par» 
ticular, are rarely the same either in number or Tolume, 
neither do the mucous glands in any way affect a fixed 
and analogous situation. 

And not only is each particular system subject to 
frequent aberrations, but the whole of the organs of 
the internal life are sometimes found in the inverse 
of the natural order. Of this I have lately seen aa 
instance. 

Let us now consider the organs of the animal life, the 
senses, the brain, the voluntary muscles, and the larynx : 
here every thing is exact, precise, and rigourously deter- 
mined. In these there is scarcely ever seen a variety of 
conformation ; if there do exist any, the functions are 
troubled, disturbed, or destroyed : they remain unaltered 
in the organic life, whatever may be the disposition of 
the parts. 

The difference with respect to action, in the organs of 
the two lives, depends, undoubtedly, upon the symmetry 
of the one, whose functions the least change of conforma- 
tion would have disturbed, and on the irregularity of 
the other, with which these different changes very well 
agree. 

The functions of every org^n of the animal life are 
immediately connected with the resemblance of the organ 
to its fellow on the opposite side if double, or if single to 
its similarity of conformation in its two halves: from 
hence the influence of organic changes upon the derange- 
ment of the functions may be well conceived. 

But this assertion will become more sensible, when I 
shall have pointed out the relations which exist between 
the symmetry and the irregularity of the organs, and the 
harmony and the discordance of their functions* 



"* 



ON UV£ AND DEATH. 25 



CHAPTER III. 

«BNBRAL DITFBKXNCE OF TH TWO LIVB8 WITH BB0AB]) 

TO THB MODB OF ACTION OF THBIB 

BBSPBCTIFB OBGANS. 

Harmont is to the functions of the oi^tns, what sym- 
metry is to their conformation; it supposes a perfect 
equality of force and action, between their similar parts, 
just as symmetry indicates an exact analQgy of external 
form, and internal structure : indeed it is a necessary 
consequence of symmetry, for two parts essentially alike 
in structure, cannot much differ in their manner of action. 
Hence we should be naturally led to the following con- 
clusion, namely, that harmony is the character of the 
animal, discordance that o£ the organic functions. But 
QU Uiese points we must be more particular. 

I. 0/ harmony qf action in- the anin^l life. 

We have already observed, that the animal life arises 
from the successive actions of the senses, the nerves, the 
brain, the locomotive organs, and the voice. We shall 
DOW consider what harmony of action is, in each of these 
great divisions. 

The precision of our sensations appears to be the more 

complete in proportion as there exists a resemblance 

between the two impressions, of which they are each of 

them. the assemblage. We see inaccurately when one 

of the eyes is better formed, and stronger than ^e other; 

when it conveys to the brain a clearer image than it9 

fellow does. It is to avoid this confusion that we shut 

one eye, while the action of the other is increased by the 

4 



26 PHYSIOLOGICAL RESEARCHES 

application of a lens, for at such time there can be no 
harmony of action in the two organs ; accordingly, we 
make use of one of them only in order to avoid the dis- 
cordance of the impression. — What a lens applied to one 
eye only produces artificially, is exemplified in a natural 
way by squinting. — We squint, says Bufibn, because 
we turn the weaker eye from the object on which the 
stronger is fixed; for in so doing we avoid the confusion, 
which would arise from the perception of two dissimilar 

images. 

We know that many other causes may contribute to 
the production of this efiect, but we cannot doubt the 
reality of the reason assigned* We know also, that in 
some animals each eye may act without the assistance of 
the other, and that two different objects may be trans- 
mitted at the same time by the two eyes of certain other 
animals ; but this circumstance, when the action of both 
the organs is united upon a single object, should by no 
means prevent a similarity in the two impressions. A 
single senss^on is the consequence of the combination ; 
but in what way can such sensation be formed with 
accuracy, if the same body at the same time be pictured 
both in strong and weak colours on the one and the other 
of the retinae ? 

What we have said of the eye may be equally well 
applied to the ear. If, of the two sensations which form 
a sound, the one be received by a strong an^ well formed 
organ, the other by a weak one, the impressions will be 
unequal ; the brain also, because it is differently affected 
by each, will .be the seat of an imperfect perception. 
Such conformation constitutes what is called an incorrect 
or false ear. For what reason does it happen that one 
man is unpleasantly affected by a dissonance, while 
another does not even perceive it ? The reason is this, 



ON LIFE AND DEATH. 27 

that in the one, the two perceptions of the same sound 
are identical ; in the other^ dissimilar.* For the same 
reason a man- with a correct ear will combine his dancing 
with the cadence of the measure given him; another 
without this similarity of organ will be as constantly at 
variance in his motions with the orchestra. 

Bufibn has confined his observations on harmony of 
action, to the organs of vision and bearing ; we shall 
push our examination of it farther. 

In the sense of smelling, as well as in the other senses, 
we must admit of two impressions ; the one primitive, 
and belonging to the organ, the other consecutive, and 
afifecting the sensorium : now the latter may vary, the 
former remaining unaltered. Many odours are disagreea- 
ble to some, but pleasant to others ; and this, not because 
there is any difference in the affection of the pituitary 
membrane, but because in different individuals, the mind 
may attach a very different sentiment to the same impres- 
sion. — Hence a variety of results does not in this case 
suppose a difference of principle. 

But sometimes the impression which is made upon the 
pituitary membrane does really differ from that which it 
ought to be, for producing perfect sensation. Two dogs 
pursue the same game ; the one never loses scent, but 
makes the same turnings and windings with the animal 

* This supposition, though no doubt ingenious, is not true. If the 
want of accuracy of hearing arose in fact from the inequality of the 
power of the two organs, this defect might be remedied by using but 
one ear; but experience gives a different result. We shall not discusF, 
in relation to the same principle of inequality of the organs, the explana- 
tion of strabismus ; but at least, for every thing that relates to the just 
appreciation of colours, this principle is no more applicable than to the 
just appreciation of sounds. I know a man who has never been able 
to distinguish the blue of the thy from tht green of the tea^ and he 
•acceedi no better by closing one eye. 



'28 PHYSIOLOGICAL RESEARCHES 

before him ; the other follows his game also, but often 
stops and hesitates, endeavors to recover the scent, pro- 
ceeds and stops again. The first of these receives a 
lively impression of the scented emanation ; the organs 
of the second are only confusedly afiected. Now it may 
be asked whether this confusion does not arise from the 
unequal action of the two nostrils, from the superior 
organization of the one, and from the imperfection of the 
other ? — the following observations appear to decide the 
question. 

In the coryza, which afiects but one of the nostrils, if 
the two be suffered to remain open, the sense of smelling 
is confused ; but let the diseased nostril be shut, and the 
smell shall immediately become distinct. A polypus in 
one of the nostrils debilitates the action of the pituitary 
membrane on the affected side, the other remaining In its 
healthy state : hence, as in the preceding case, ensues a 
want of harmony in the two organs, and the same confu- 
sion in the perception of odours. The greater number 
of the affections of a single nostril have similar effects, 
which may be all of them corrected by the same means. 
And wherefore? because in rendering one of the pituitary 
membranes inactive, we put a stop to the discordance 
tfhich is occasioned by the deficiency of action in the 
other. From the above facts (since any accidental cause, 
which destroys the harmony of action in these organs, 
is capable of rendering the perception of odours inexact) 
we may conclude, that when the perception is naturally 
inaccurate, there is a natural dissimilarity in the forma- 
tion of the organs, and therefore a difference of power in 
them. 

The same reasoning may be applied to the sense of 
taste. It is often the case that one side of the tongue is 
affected by palsy or spasm, the median line dividing the 



ON LIFE AND DEATH. 2S 

ineensible half from the other, which continues to pre- 
serve its sensibility. But such affection may take place 
in a variety of degrees, and one side of the tongue retain 
a power of perceiving savours though in a less perfec- 
tion than the other side. In such case it is natural to 
suppose that the taste- must be confused; because a clear 
perception cannot be the consequence of two unequal 
sensations. 

The perfection of the touch as well as that of the other 
senses, is essentially connected with uniformity of action 
in the* two symmetrical lialves of the body, and particu- 
larfy in the hands. Let us suppose, for instance, a man 
born blind, to have one hand well organized, the other 
defective in the power of moving the thumb and fingers, 
and forming only a stiff" and immovable surface ; such 
{person would find it a very diflScult thing to acquire a 
just notion of the size and figure of bodies, because the 
same sensation would not arise from the successive appli- 
cation of each hand to the same substance. Let both 
of his hands, for example, be supposed to touch a small 
sphere ; the one by the extremities of the fingers will 
embrace it in all its diameters, and convey to him the 
idea of roundness ; the other, which will be in contact 
with it only in a few points, will produce a very different 
sensation. Embarrassed between these two bases of iiis 
judgment, he will scarcely be able to decide, nay, it is 
even possible that he may form a double judgment from 
the double sensation which is presented him : his ideas 
would be more correct were he to use only the perfect 
hand, in the same manner as the person who squints, 
makes use of the perfect eye only. Our hands then assist 
each other reciprocally; the one confirms the notions 
which are given us by the other; hence the necessary 
uniformity of their confonnation. 



\ 



30 PHYSIOLOGICAL KES£ARCIILS 

The hands are not the only instruments of the sense 
of touch. The axilla, the groin, the concavity of the 
foot and many other parts, may all of them from their 
application to bodies, afford us so many bases for our 
judgments with regard to external form. Now, if one 
half of the body were differently arranged from -the other 
half, the same uncertainty in perception would infallibly 
be the result. From all that has been said, we may 
conclude, that in the external organs of sense, a harmony 
of action in the two symmetrical parts, or the two similar 
halves of the organ, is a condition essential. to the per- 
fection of sensation. * 
■ The external senses are the natural excitants of the 
brain. The functions of the brain succeed tO/ theirs, and 
this organ would but languish, were it not to find in them 
the principle of its activity. From sensation follow 
perception, memory and imagination ; from these the 
judgment. Now it is easy to prove, that these different 
functions, commonly known by the name of the internal 
senses,^ are governed in their actions by the same laws, 
which influence the external senses ; and that like them, 
they approach the nearer to perfection in proportion to 
the degree of harmony existing in the symmetrical parts, 
in which they have their seat. 

Let us suppose for instance one hemisphere of the 
brain to be better organised, and therefore susceptible of 
livelier affections than its fellow ; in such case the per- 
ception of the individual would be confused, for the brain 
is to the soul what the senses are to the brain; it transmits 

* We caDnot, without confounding all ti^e ideas we bave formed of 
the senses, give thi< name to the memory, imagination and judgment ; 
at the most we might give the name of internal senses to cer^in «enaa-- 
tions which inform us of the particular state of some internal organ, in 
the same way as the external senses make us acquainted with th« 
properties and state of external bodies. 



ON LIFE AND DEATH. 31 

to the soul the impressions conveyed to it by the senses, 
as the senses convey to the brain the impressions made 
upon them by. external objects. But, if the defect of 
harmony in the external- senses confuse the perception of 
the brain, why may not the soul perceive but confusedly, 
when the two hemispheres of the brain are unequal in 
power, and incapable of blending into one the double 
impression, which is made upon them ?. 

The memory is the faculty of re»producing former 
sensations, the imagination that of creating new ones, 
now in the act of remembering or imagining, each hemis- 
phere of the brain appears to re-produce, or to create 
a sensation of its own. If both do not act alike, the 
perception of the mind, which ought to be the result of 
the two sensations united, will be inexact and irregular. 
But, it is evident, that there will be a disparity in the 
two sensations, if there be a disparity in the two halves 
of the brain, in which they have arisen, and since the 
general foundations of the judgment are made up of the 
faculties of perception, memory, and imagination, if these 
be confused, the judgment itself must be confused also. 

We have now supposed an inequality of action in the 
Iiemispheres of the brain, and inferred, that the functions 
%vou]d in this supposition be imperfect ; but %vhat as yet 
is only supposition, in a variety of instances can be 
proved to be a fact ; for nothing 'is more common than to 
find in consequence of compression bn either hemisphere 
])y blood, pus, or exostosis^ a variety of alterations in the 
intellectual functions. 

Even when all appearances of actual compression have 
vanished, if in consequence of that which has been 
experienced, a part of the brain remain enfeebled, the 
same alterations of mental power will be found to be 
prolonged. If both hemispheres of the* brain, however, 



32 PHTSIOLOOICAL RESEARCHES 

be affected equally, the judgment though weaker, will be 
more exact* Perhaps it is thus, that we should ezplaia 
those observations so frequently repeated, x^f an accidental 
stroke upon one side of the head having restored the 
intellectual functions, which had long remained dormant 
in consequence of a blow received upon the other side. 

I now conceive myself to have proved, that with 
inequality of action in the hemispheres, there must be 
confusion of intellect. I have also pointed out some 
states of disease, in which such confusion is evidently 
the effect of inequality of action so occasioned ; here we 
see the effect and its cause; but may we not from analogy, 
infer a similar cause where we see a like effect ? when 
the judgment is habitually incorrect, and all the i^eas 
wanting in precision, may we not be induced to believe, 
that there does exist a defect of hamtony in the action of 
the two hemispheres of the brain ? We see inaccurately 
if nature have not given to both eyes an equal power ; 
we perceive and judge inaccurately in like manner, if the 
two sides of the brain are naturally dissimilar. The most 
correct mind, and the soundest judgment, pre-suppose ia 
the hemispheres a perfect harmony of action ; < and what 
a multiplicity of shades do we not behold in the opera- 
tions of the understanding? it is probable that they all of 
them correspond to so many varieties in the proportions 
of power in the hemispheres. Could we squint with the 
brain as we do with the eyes — ^that is to say, could we 

* We cannot conceive bow the joéigment can be weak or strong, if 
we do not understand bj it that it is babitaaUj accurate or inaccurate. 
H is judgment is sound who usuallj perceives the true relations between 
things ; and this is independent of the number and variety of the ideas 
upon which he has to pronounce. The man to whose mind there is 
presented but a small number of relations, has but little imagination ; 
bat if these relations be true, we cannot saj that bis judgment is 
weak. 



ON LIFE AND DEATH. 33 

rèeeiye impressions on one hemisphere only, and form 
from thence our determinations, we might then command 
at will, a precision in our intellectual operations ; but 
such a power does not exist. 

To the functions of the brain succeed those of locomo- 
tion and the voice. The nrst of these would appear 
almost to form an exception to the general law. In 
considering the two vertical halves of the body, we shall 
perceive tiiat the one is constantly more powerful thaa 
the other with respect to the strength and number of its 
movements. The right half is that, which from custom, 
is most made use of. 

To comprehend the reason of this difference; we 
must make a differerence between strength and agility; 
strength depends upon the perfection of the organizfition, 
on the energy of the nutritive process, on the plenitude 
of life in the muscular fibre ; agility, on the contrary, is 
the result of habit and frequent exercise.* 

^Bicbat, in order to retain for the organs of organic life the character 
of irregularity in the forms which he had assigned to them, has been 
compeUed to aYail himself of the inequalitj of the size of the con* 
generous organs. He soon repented having established an uniform 
principle ; and^n this case for example, he is near being condemned 
bj the yerj sentence which he has himself pronounced. The loco- 
notive system, in fact, the symmetry of which no person before him 
thought of denying, is destitute of it according to the principle he has 
established, since it presents in its two halves an inequality of size and 
action. In order to avoid this consequence, Bichat has maintained that 
the inequality of size aro»e from the inequality of action» and that this 
was the result, not of an original disposition, but of our social habits 
only. To prove this assertion, he has been compelled to heap sophism 
on sophism ; he cannot in this case be suspected of a wish to deceive ; 
he was convinced of the truth of the principle, and we know that to 
prove what is believed to be true, the weakest reasons always seem 
to be sufficient. But these very errors should be turned to our advan- 
tage, by showing us how dangerous is the tendency of generalivng 

5 



34 PHYSIOLOGICAL REESARCIIES 

At present we shall observe, that this disparity of 
action in the locomotive organs, docs not consist in the 
difference of their actual strength, but in that of the 
agility, with which these motions are executed. — All is 
equal in the size, in the number of fibres, and nerves 
both of the one and the other of the superior, or inferior 
extremities; the difference of their vascular systems is 
scarcely any thing. From hence it follows that the 
discordance does not exist in nature, but that it is the 
effect of our social habits, which by multiplying our 
movements on one side of the body, increase their 
address without much adding to their power. Such in 
fact are the wants of society, as to call forth a certain 
number of general movements, which must be performed 
by all in the same direction, in order to be understood. 
It is generally agreed, that this direction shall be from 

upon every thing, lioce it was capable of mieleading to jodicious a 
mind. 

Without stopping to refute in detail all the reasons which he hai 
adVanced io support bis opinion, we cannot help sajing something of 
tbem; and in the first place, the difference of size uniformly esiats; it 
is evident that it does not arise from great exercise, since it is found in 
the infant at birth, and the nourishing artery of the right arm is larger 
than that of the left If the right arm be not really stronger than the 
other, why should we always use it in preference ? If we employ it in 
writing, should we say with Bichat, that it is only because it is better 
•itnated to move from left to right, in the order in which the character! 
of our writing succeed each other ; might it not be said, with more 
reason, that our letters go from left to right, because it is the direction 
in which the right hand most easily traces tbem ? All this besides 
relates merely to the form uf our characters, since all the oriental 
lauguages are written from right to left ; yet it is always done with the 
right hand. Is it still said that the necessity of union in battle has led 
to the employment of the right arm to hold the weapons, as if the 
Hurons or Algonquins fought in close ranlâ like our Orenqdiers. If this 
use of the same arm or the same leg was only conirentiona], why among 
tfome people, is the left side never preferred ? 



ON LIFE AND DEATH. 35 

left to right. The letters, which form the %vriting of 
most nations, are in this way directed; such circumstance 
occasions the necessity of our using the right hand to 
form them in preference to the left, the former being as 
much better adapted to this method, as the latter would 
be to the contrary one; of this we may convince ourselves 
by experiment. 

The direction of the letters from left to right, imposes 
on us the necessity also of casting our eyes upon them 
in the same direction. From this habit acquired in 
reading, arises that of examining objects in the same 
manner. 

The necessity of similar movements when men are 
drawn up in line of battle, has induced almost all nations 
to handle their weapons with their right hands; the 
harmony too which prevails in the dances of even the 
most savage people exacts an accord in the limbs, which 
they constantly preserve by making all their principal 
movements with the right. We might add to these 
examples a great variety of others. 

The general movements agreed on by society, which, 
if every one were not to execute them in the same 
direction, would be creative of much confusion ; these 
movements, I say, by the influence of habit, oblige us for 
our own particular movements to use the limbs, which 
they have brought into action. Hence, the members of 
the right side of the body are perpetually in action either 
for our own particular wants, or for those which we feci 
in conjunction with others. 

Now, as the habitude of acting, continually tends to the 
perfection of action, we may perceive the reason, why the 
right side acquires a greater facility in the performance 
of many motions than the left. This increased facility is 
not original, but acquired. 



36 PHYSIOLOGICAL RESEARCHED 

So remarkable a difference then, ia the two symmetrical 
halves of the bodj, is not by nature meant as an excep- 
tion to the general law of harmony of action in the external 
functions ; for those movements, which are executed by 
the whole of the body, are the more precise in proportion 
to the smallness of the difference existing in the agility 
of the muscles of the two sides. How happens it that 
certain animals leap from rock to rock with such admira- 
ble precision, where the least deviation from the intended 
direction, would plunge them into an abyss ? how happens 
it that they run with such astonishing address on planes, 
which are scarcely equal in breadth to the extremities of 
their limbs ? how happens it that the walk of the very 
heaviest of animals is never attended with those false 
steps so frequent in the progression of man ? The reason 
must be, that the difference in their locomotive organs 
in both sides of the body is scarcely any thing, and that 
in consequence there must be a constant harmony of action 
in these organs. 

He, whose general movements, or those of the whole 
of the body are the most perfect, has the least command 
in particular over those of the right side ; for, as I shall 
prove hereafter, the perfection of a part is never acquired 
but at the expence of that of the whole. The child, who 
«hould be taught to make an equal use of all his limbs, 
would possess a precision in his general movements, which 
he would find extremely difficult to acquire for those of 
the right hand, such as writing or fencing. 

I can easily suppose, that some few natural circum- 
stances may have exercised upon us an influence in our 
choice with respect to the direction of those general 
motions, which the habits of society have established. 
Such may be the slight excess of diameter in the right 
subclavian artery, and the sensation of lassitude during 



ON LIFE AND DEATH. 37 

digestion, which is more perceived upon the left side on 
account of the situation of the stomach, and may there- 
fore have determined us to act at such time upon the 
opposite side in preference. Such also may be tlie 
natural instinct, by which, to express our feelings we 
carry the right hand to the heart; but these circumstances 
are trifling in comparison with the very great difference 
of the movements which from the state of civilization 
exists between the symmetrical halves of the body ; and 
from this view of the subject, we cannot but regard this 
difference as the effect of social convention, and by no 
means the intent of nature. 

The voice, together with locomotion, is the last act of 
the animal life in the natural order of its functions. Now 
the greater number of physiologists, and Haller in particu- 
lar, have indicated as the causes of want of harmony in 
the voice, the dissimilarity of the two portions of the 
larynx, the inequality of force in the muscles, which 
move the arytenoid cartilages, the same inequality of 
action in the nerves, which are distributed to each half of 
the organ, and the different reflection of sounds in the 
nostrils and frontal sinuses. Without doubt a defective 
voice must frequently depend upon a faulty ear ; when 
we hear incorrectly, we sing incorrectly ; but when a 
correct ear is united with a want of precision in the voice, 
the cause is then in the larynx. 

The most harmonious voice is that, which the two por- 
tions of the larynx produce in an equal degree ; where 
the vibrations on one side correspond exactly in number, 
strength and duration with those upon the opposite side.* 

* The theory of wind inttnimcnts is not yet sufficiently well under- 
stood^fo enable us to say, what sort of inflaence would be exerted upon 
the lomid by the inequality of yibrating plates. 

(See the article Voice, in my Elements of Physiology, Vol. 2dr)-' 



38 PHYSIOLOGICAL RESEARCHES 

Iq the same manner the most perfect singing will be 
produced by two voices exactly similar in tone, compass, 
and inflection. 

From the numerous considerations which I have offer- 
ed, the following general conclusion may be deduced — 
namely, that one of the most essential characteristics 
of the animal life, is a harmony of action in the two 
analogous parts, or in the two sides of the simple organ 
concurring to the same end. The relation which exists 
between this harmony of action, which is the character 
of the functions, and symmetry of form, which is the 
attribute of the organs of the animal life, will easily be 
seen. 

I wish to observe in finishing this section, that in 
pointing out the different derangements, which take place 
in the animal life, from the want of harmony in the 
organs, I have only pretended to assign a single isolated 
cause of such derangements; I am well aware that a 
thousand other causes besides dissimilarity in the hemis- 
pheres of the brain, may affect the operations of the mind. 

II. Of discordance of action in the organic life. 

Along with the phenomena of the animal life, let us 
now consider those of the organic life, and we shall find 
that harmony has nothing to do with them. Of what 
detriment would it be to the general health of the indi- 
vidual, should one of his kidneys be stronger than the 
other, and secrete more urine ; should one of his lungp 
be better unfolded than the other, admit more venom, 
and send out more arterial blood ; should a less organic 
force be the lot of the salivary glands on one side than 
on the other side of his body ? The simple function, to 
which both organs concur, would not be performed less 



ON LIFE AND DEATH. 3^ 

perfectly. Whenever but a slight fulness superrenes on 
one side of the liver, spleen , or pancreas, the sound part 
makes up for the defect, and the function is little disturb- 
ed. The circulation also remains unaltered among the 
frequent variations in the vascular system of each side 
of the body, whether such variations exist naturally, or 
"whether they arise from some artificial obliteration of the 
larger vessels as in aneurism. 

Hence we find those numerous irregularities of struc- 
ture, those malconformations, which as I have said may 
be remarked in the organic life, and nothing of a morbid 
nature in consequence arising. From hence we see that 
almost continual succession of modifications, wbich lessen 
or increase the circle of the organic functions. The vital 
powers, and their exciting causes, are continually varying, 
und thus occasion a constant instability in the functions 
of the organs, for a thousand causes may at every moment 
double or triple the activity of the circulation, and respi- 
ration, increase or diminish the quantity of bile, urine, or 
saliva, and suspend or augment the nutrition of the parts» 
Hunger, food, sleep, motion^ rest, and the passions may all 
of them impress upon these functions so great a mobility, 
as every day to make them run through a hundred degrees 
of strength or weakness. 

In the animal life on the contrary, every thing is 
uniform and constant, the powers of the senses cannot 
experience these alternate modifications, or at least, not 
ID 80 marked a manner. Indeed they are at all times in a 
iMe of relation with the physical powers, which preside 
•t«r exterior bediAf ; now the latter remaining unaltered, 
saeh variations Witfald destroy all relative connexion, and 
thus the functions cease. 

Besides, if this mobility, which characterises the organic 
lifej were the attribute of sensation — for the same reason 



40 PHYSIOLOGICAL RESEARCHES 

it would be that of all the operations of the mind. In 
such case of what would man consist ? The perpetual 
sport of every thing surrounding him, he would find his 
existence at one time little difierent from that of inanimate 
matter, at others superior in perfection and energy to that 
even which he now enjoys, allied at one time to the brute, 
at another, to spiritual nature. 



CHAPTER IV. 

GENERAL DIFFERENCES OF THE TWO LIVES WITH RESPECT 

TO DURATION OF ACTION. 

One of the great distinguishing characters of the phe- 
nomena of the animal life in opposition to those of the 
organic life, has just been shewn. That, which I am about 
to examine, is not of less importance. The functions 
of the animal life intermit ; the functions of the organic 
life are performed with an uninterrupted continuity. 

I. Of contimiily of action in the organic lif^. 

Prolong but little the causes which are capable of 
suspending respiration^ or the circulation of the blood, 
and life itself shall be suspended, nay, even annihilated. 
All the secretions go on uninterruptedly; if they intermit 
at all (and those of the bile and saliva for instance, whan 
not immediately required for the purposes of digestioa 
and mastication, may be said to intermit) such interfhis- 
sions afiect the intensity of the secretion only, and not 
the entire exercise of the function. Exhalation and 
absorption incessantly succeed each other \ the process 






ON LIFE AND DEATH. 41 

of nutrition must be continually carried on ; the double 
movement of assimilation and decomposition from which 
it results, can only be terminated with life itself. 

In this concatenation of the organic phenomena, each 
function depends immediately upon those which preeede 
it. The centre of them all, the circulation, is immedi- 
ately connected with the exercise of them all, for when 
this is troubled, they languish, when this ceases, they cease 
also. Just in the same manner the Aiovements of a clock 
all stop with the pendulum. Nor only is the general 
action of the organic life connected wi(h the heart ; but 
there cannot exist a single function of this nature uncon- 
nected with all the others, for without secretion, there 
can be no digestion, without exhalation no absorption, 
without digestion no nutrition. Hence as a general 
character of the organic functions may be indicated con- 
tinuity of action, and mutual dependence. 

II. Of intermission of action in the orgtmic) life. 

In the exercise of the functions of the animal life, 
there will be regularly seen an alternation of activity 
and repose, complete intermissions, and not remissions 
only. 

Fatigued by long continued action, the senses all alike 
become for a time, incapable of receiving any further 
impression. The ear loses its sensibility to sound, the 
eye to light, the tongue to savours, the pituitary mem- 
brane to smells, thei touch to the qualities of bodies about 
which it is conversant, and all this for the sole reason that 
the respective functions of these different organs, have for 
a long time been exercised. 

In like manner, the brain fatigued by too great an 

effort in the exercise of any of its powers, in order to 

6 



42 fHTSIOLOGICAL RESEARCHES 

regaia its excitability^ must cease to act for a period pro- 
portioned to the duration of its preceding action. The 
xnusclofli also after having been strongly contracted, before 
they can contract anew, must remain for awhile in a state 
of relaxation. Hence in locomotion, and the exertion of 
the voice, there must be intermissions. 

Such ihen is the character peculiar to the organs of the 
animal life. They cease to act because they have acted. 
They become fatigued^ their exhausted powers must be 
renewed. 

This intermission is sometimes' general, sometimes 
partial. When a single organ, for a long time, has been •/ 
exercised, the others remaining inactive, it relaxes and 
sleeps, the others continuing to watch. — Hence, without ^ 
doubt, proceeds the reason, why there is no immediate 
dependence among the functions of this order on each 
other. The senses being shut up against sensation, the 
brain may still subsist in action, may remember, imagine, 
or reflect. In such case the power of locomotion and the 
voice also, may equally well be exercised, and these in 
like manner may remain unexercised, and the activity of 
the senses be in no-wise impaired. 

Thus the animal at will may fatigue any one of the 
parts of this life, and on this very account, such parts 
must all of them possess a capability of being relaxed, a 
power of repairing their forces in an isolated manner. 
This is the partial sleep of the organs. 

III. application of the law of intermission of action 

to the theory of sleep. 

General sleep is the sleep of all the parts. It follows 
from that law, which with respect to the functions of the 
animal life, enchains intermission with periods of action^ 



' • 



ON LIFE AND DEATQ, 43 



* 



ftoni that law, by which this life is particularly distinguish- 
ed from the organic life. 

Very numerous varieties are remarked in this periodi- 
cal state, to which all animals are subject. The most 
complete sleep is that in which the outward life is entirely 
suspended. The least perfect' sleep is that which affects 
one organ only ; it is that of which we have just been 
speaking. 

Between these two extremes there are many interme- 
diate states. At times perception, locomotion, and the 
voice only are suspended ; the knagination, the memory, 
and the judgment remaining in action. At other times, 
to the exercise of the latter faculties are added those of 
the locomotive organs and the voice. — Such is the sleep, 
in which We dreapn, for dreams are nothing more than a 
portion of the animal life escaped from the torpor, in 
which the other portion of it is plunged.. 

Sometimes but very few of the senses have ceased their 
communication with external objects. Such is that spe- 
cies of somnambulism, in which to the action of the brain, 
the muscles, and the larynx, are added the very distinct 
actions of thé ear and the sense of touch.* 

* The action of the brain is far from being preserved in somnambulism. 
The thread of ideas, on the contrary, is completely broken, and this is 
the most striking character which distinguishes every kind of sleep 
from wakefulness. The mind then cannot reflect upon the sensations 
which it receives, it abandons itself successively and without any 
resistance to all those which are presented, without examining the con- 
nexion which they can ha?e between them. In ordinary sleep, the 
senses are almost entirely blunted, the mind receives no other sensa. 
tions than those which have been derived from memory ; but they 
present themselves in a confused manner, without order and in such a 
way as often to form the most strange and incoherent images. In 
somnambulition the action of many senses, and that of hearing in 
particular is preserved ; the judgment of the sleeper can then exercise 
itself not only upon its reminiscences, but also upon the impressions 



44 PHYSIOLOGICAL RESEARCHES 

Sleep then cannot be considered as a constant and 
invariable state with regard to its phenomena. — Scarcely 
ever do we sleep in the same manner twice together. 
A number of causes modify in applying to a greater or 
less portion of the animal life the laws of intermission 
of action. Its difijsrent degrees should be marked by the 
different functions, which these intermissions affect. 

But the principle of it is every where the same from 
the simple relaxation of a muscle to the entire suspension 
of the whole of the animal life* Its application, how- 
ever, to the different external functions, varies without 
end* 

id 

These ideas on sleep are different, no doubt, from that 
narrow system, where its cause exclusively placed in the 
brain, in the heart, in the large vessels, or in th^ stomach, 
presents an isolated and frequently an illusory phenome- 
non, as the base of one of the great modifications of 
life. 

And what is the reason why light and darkness in the 
natural order of things, coincide so regularly with the 
activity or intermission of the external functions ? The 
reason is this, that during the day a thousand means of 
excitement perpetually surround the animal, a thousand 
causes exhaust the powers of his sensitive and locomotive 
organs, fatigue them, and prepare them for a state of 
relaxation, which at night is favoured by the absence 
of every kind of stimulus. Thus, in the actual state of 

which are transmitted to it from without. The sound of a bell or a 
drum, being heard while we are in a dream, will immediately modify it. 
In this way a person may gain the attention of a somnambulist, and as 
the latter possesses the use of his voice, it will be seen by his answers 
that his ideas can be directed at will, and led in this way wherever it 
is wished; for the impressions that he receives from without, being 
stronger than those which come from memory, he will almost alwayé 
obey the first. 



ON LUT AND D£ATH. 45 

society^ where this order is in part inverted, we assemble 
about us at evening, a variety of excitants, which prolong 
our waking moments, and put off until towards the first 
hours of daylight, the intermission of our animal life, an 
intermission, which we favour besides by removing from 
the pldce of our repose whatever might produce sensa- 
ion. 

We may for a certain time, by multiplying the causes 
of excitement about them, withdraw the organs of the 
animal life from this law of intermission, which should 
naturally cause them to sleep ; but at last they must 
undergo its influence, and nothing can any longer suspend 
it. Exhausted by watching, the soldier slumbers at the 
cannon's side, the slave under the whip, the criminal in 
the midst of torture. 

We must carefully make a distinction, however, be- 
tween the natural sleep, which is the effect of lassitude, 
and that, which is the consequence of. some affection of 
the brain, of apoplexy, or concussion, for instance. In 
the latter case the senses watch, receive impressions, and 
are affected as usual, but these impressions are not per- 
ceived by the diseased sensorium; we cannot be conscious 
of them. On the contrary, in ordinary sleep the senses 
are affected as-much, or even more than the brain. 

From what has now been said, it follows, that the 
organic life, has a longer duration than the animal life. 
In fact the sum of the periods of the intermissions of the 
latter, b almost equal to that of the times of its activity. 
We live internally almost double the time that we exist 
externally. 



46 PHYSIOLOGICAL RESEARCHES 



CHAPTER V. 

GENERAL DIFFERENCES OF THE TWO LIVES WITH RESPECT 

TO HABIT. 

Another of the great distinguishing characters of the 
two lives of the animaly consists in (he independence of 
the one^ and in the dependence of the other on habit. 

I. Of habit in the animal life. 

m 

/ 

In the animal life every thing is modified by habit. 
The functions of this life, whether enfeebled or exhausted 
by it, according to the different periods of their activity, 
appear to assume a variety of characters : to estimate the 
influence of habit, it is necessary to consider two things 
in the effect of all sensation, the sentiment, or immediate 
feeling, which we have of external objects, and the judg- 
ment which is the result of one or more comparisons 
made with respect to them. An air, for instance, strikes 
the ear ; the first impression made upon tKe organ is, we 
know not why, agreeable or painful. This is sentiment — 
at present let us suppose the air to be continued. We 
may now endeavour to appreciate the different sounds of 
which it is composed, and to distinguish their accords. 
In this we exercise the judgment. Now, on these two 
things, the action of habit is inverse. It enfeebles our 
sentiment of things, it improves our judgment of them ; 
the more we regard an object, the less are we sensible of 
its agreeable or painful qualities, the better, at the same 
time, may we judge of its attributes. 



ON LIFE AND DEATH. 47 



11. Habit blunts the sentiment. 
• 
Let us dwell a little on the foregoing proposition ; we 
have said that it is the property of habit to enfeeble our 
sentiments of things, to bring us into a state of indifier- 
ence, the middle term betwixt pain and pleasure. But 
before we set about to prove an assertion so remarkable, 
it will be well to fix the sense of it with some precision. 
Pain and pleasure are absolute and relative.* The instru- 
ment which tears u^ in pieces is a cause of absolute 
pain. Sexual connexion is a pleasure of the same nature. 
Again, the view of a beautiful country delights us, but 
here the enjoyment is relative to the actual state of the 
mind only ; its charms have long since been indifferent 
to the inhabitant of the spot. A bougie when for the 
first time passed into the urethra is painful to the patient ; 

* Pleuore and pain are always absolute sensations, but they may 
depend upon relative circumstances ; that degree of cold, for example^ 
d«M not incommode the inhabitant of Spitzbergen, which would be 
Tery painful to a man from a temperate climate. lu order to under- 
stand how habit produces these effects, we must recollect that the 
repetition of the same sensations on the same part exhausts at length the 
sensibility of it Hence we may conceive how the contact of a body 
upon a living rorfaot may cease to be painful, while any division or 
solution of continuity of one of our organs will be always more or less 
so, because the nerves that are divided are unaccustomed to this 
sensation, and still possess their whole sensibility. The sense of sight 
furnishes us with a striking example of sensibility being exhausted by 
the continuation of the sensation ; if we look for a long time with the 
same eye upon a white surface with a red spot in the middle of it, and 
then look upon a part that is all white, we shall perceive there a. 
greenish spot ; for the part of the retina .which has been a long time ia 
contact with the red rays, lo.«es the peculiar sensibility that enables it 
to transmit this sensation perfectly ; and of all the coloured rays which 
compose the white rays that now go to it, it transmits only those to 
which it is unacquainted ; hence results the sensation of green. 



48 PHYSIOLOGICAL RESEARCHES 

eight days afterwards he is no longer sensible of it. 
Here we have comparative pain. Whatever destroys the 
texture of the organ is always productive of an absolute 
sensation ; the simple contact of bodies at no time pro- 
duces any other than a relative sensation. 

Hence it is evident that the domain of absolute pleasure 
or pain, is much less extensive than that of these feelings 
when relative. The very words agreeable^ or painful, 
imply a comparison made between the impression receiv- 
ed by the senses, and the state of mind on which it is 
received. Now it is manifest that we could have referred 
only to relative pain and pleasure, as being submitted to 
the influence of habit. On these we shall occupy our- 
selves awhile. 

And to shew that they are gradually worn away by 
habit as we have said, to the point of indifference, a 
variety of proofs; may be adduced. Every foreign body 
in contact for the first time, with a mucous membrane, is 
creative of a disagreeable sensationj which by repetition^ 
is diminished, and at last becomes altogether impercepti- 
ble. Pessaries in the vagina, tents in the rectum, the 
canula made use of for tying polypi of the nose, or the 
uterus, bougies, in the urethra, in the oesophagus, or 
trachea, styles and setons in the lachrymal passages, pre- 
sent us every day with these phenomena. The impres- 
sions of which the cutaneous organ is the seat, are all of 
them subjected to the same law. The sudden passage 
from cold to heat, or from heat to cold, is always the 
occasion of a disagreeable sensation, but such sensation 
gradually and at last entirely disappears, if the tempera- 
ture of the atmosphere be within a certain range and 
constant. From hence proceed those various sensations, . 
which we have from the change of climate, or season. 
Similar phenomena in the same way are the result of our 



ON LIFE AND DEATH. 49 

successive perceptions of the dry or humid, the soft, or 
the hard qualities of bodies, and in general the same 
may be said of all our relative sensations, of what kind 
soever^. 

With respect to pleasure, we shall repeat what we 
have said of pain. The perfumer and the cook are by 
no means sensible in their several professions of those 
pungent enjoyments of which they are dispensers. In 
them the habit of perceiving has blunted the sentiment* 
The same is the case with all agreeable sensations what- 
ever. Delightful views and delicious music are produc- 
tive of a pleasure, the vivacity of which is soon lessened ; 
for harmony and beauty if they for a long time continue 
to solicit our attention, are successively the sources 
of pleasure, of indifference, of satiety, nay even of dis- 
gust and aversion. This remark has been felt by all; 
Philosophers and Poets have all of them turned it to their 
account. 

From whence arises this facility, which our sensations 
have of undergoing so many different, so many contrary 
modifications ? To conceive it, let us first remark that 
the centre of these revolutions of pleasure, of pain^ and of 
indifference, is by no means seated in the organs, which 
receive or transmit the sensation, but in the soul. The 
affections of the eye, of the tongue, and the ear, are at 
all times the same from the same objects, but to these 
affections at different times, we attach a variety of senti- 
ments. In the second place we shall observe, that the 
action of the mind in each several sentiment of pain or 
pleasure, which has been the effect of a sensation, consists 
in a comparison between this sensation, and that by 
which it has been preceded, a comparison, which is not 
the result of reflection, but the involuntary effect of the 

first impression of the object. Now^ the greater the dif- 

7 



il 



50 niYSIOLOGlCAL RESEARCHES 

ference between the actual and the past impression, the 
livelier will be the sentiment. The sensations whicli 
affect us the most, are those which we never before have 
experienced. 

The consequence is, that in proportion as the same 
sensations are repeated, the less impression do they make 
upon us, because the comparison between the present and 
the past becomes less sensible. Pain then and pleasure 
naturally tend to their own annihilation. Tlie art of 
prolonging our enjoyments, consists in varying their 
causes. Indeed were I to regard the laws of our material 
organization only, I might almost say, that constancy is 
but one of the happy dreams of the poet, and that the 
sex to which we at present bend, would possess but a very 
weak hold upon our attentions were their charms too uni- 
form; I might almost assert that were every female cast in 
the same mould, such mould would be the tomb of love. 
But here let us forbear to insist upon the principles of 
physiology, where they tend to the destruction of those 
of morality. The one, and the other are equally solid, 
though sometimes at variance. We shall only notice, 
tbat at times the former unhappily are our only guides. 
It is then, that love disappears, with the pleasure which 
it has procured, and leaves us but disgust. It is then, that 
recollection too often carries us aside from our duties in 
rendering uniform that which we feel and that which we 
have felt, for such appears to be the essence of physical 
happiness, that past pleasure enfeebles the attraction of 
that which we enjoy. 

The consequences are clear. Physical pleasure is 
nothing but a comparative sentiment ; it ceases to exist 
when uniformity supervenes between the actual and past 
impression. By means of this uniformity habit must 
bring down pleasure to indifference : Such is the secret 



ON LIFE AND DEATH. 51 

of the very great influence which it exercises over our 
enjoyments. 

Such also is its mode of action on our pains. Time 
flies, it is said, and carries away sorrow'; time is the true 
remedy of grief; and wherefore? The reason is, that 
the more sensations it accumulates upon that which has 
been painful, the more does it enfeeble the sentiment of 
comparison between what we are, and what we were. 
At last this sentiment becomes extinct. There are no 
eternal sorrows. 

III. Habit improves the judgment. 

I have just now proved that the sentiment is enfeebled 
by the efiect of habit It is as easy to demonstrate, that 
habit improves and enlarges the judgment. 

When, for the first time, the eye wanders over an 
extensive country, or the ear is- struck by a succession of 
harmonious proportions ; when the taste, or the smell for 
the first time are afiected by any very compound savour 
or scent, there arise from these sensations only confused 
and inexact ideas. We represent to ourselves the whole, 
its parts escape us. But let these sensations be repeat- 
ed, and in proportion as they are so, will the judgment 
become precise and rigorous, and the knowledge of the 
object be perfected. 

Let us for instance observe the man, who a stranger to 
theatrical amusement of every kind is «introduced to the 
Opera. He will have but a very imperfect notion of it. 
The dancing, . the music, the scenery, the actors, the 
splendor of the whole will be all confounded within his 
mind in a sort of delightful chaos. But let him be 
present at many representations, and whatever in this 
charming whole belongs to the several arts, will assume 



) 



52 PHYSIOLOGICAL RESEARCHES 

its separate place* He will have seized its detail, may 
form a judgment of it, and this he will do the more 
accurately in proportion to his opportunities of observa- 
tion. 

The above example affords us an abridgment of the 
picture of the man, who enjoys for the first time the 
spectacle of nature. The child, at its birth, is only capa- 
ble of general impressions, but habitude, by gradually 
blunting these impressions, enables him to seize the 
particular attributes of bodies, and teaches him to see, to 
hear, to smell, to taste and to touch, by making him in 
each sensation descend successively from the confused 
notion of the whole to the precise idea of its parts. The 
animal life needs education, and this is one of its great 
characters. 

Habit then while it hebetates our sentiments, improves 
our judgments of things. An example will render this 
truth indisputable. Most persons may recollect that in 
traversing a meadow, embellished with a variety of 
flowers, they have been sensible of a general fragrance 
only, the confused assemblage of all the particular odours 
which are exhaled from each -individual, flower ^.Iwt in. a 
short time from habit this first sentiment is weakened, ft 
is soon afterwards altogether effaced. They then may 
have distinguished the odour of each particular plant, and 
formed a judgment at first impossible. 

The two contrary operations thus of habit on our senti- 
înents and judgments, tend as we see to one common end, 
the improvement, namely, of the animal life* 

IV. Of habit in the organic life. 

Let us at present compare the above-mentioned phe- 
nomena with those of the organic life, and the latter we 



I 



ON LIFE AND DEATH. 53 

shall see as constantly withdrawn from the influence of 
habit, as the former are subject to it. — Habit has never 
modified the circulation, or respiration, has never changed 
the mode of the processes of exhalation, absorption, or 
nutrition. A thousand causes would every day endanger 
our very existence, were these essential functions under 
the influence of habit. 

The excretion of the urine and fecal matter may, never- 
Uieless^ be suspended, accelerated, and return according 
to laws determined by habit. The action of the stomach 
with respect to hunger, and its contact with certain 
aliments^ appears also to be subordinate to habit; but 
here let us remark, that these difierent phenomena hold, 
as it were, a middle place between the two lives, are 
found on the limits of the one and the other, and partici- 
pate almost as much of the animal as the organic life. In 
fact, they all of them take place on mucous membranes^ 
a species of organ, which beii^ at all times in relation 
with bodies foreign to our n*ature, is the seat of an inward 
tactf in every way analogous to the outward tact of the 
skin. The two must be necessarily subject to the same 
laws. — Can we be astonished at the influence of habit on 
both of them ? 

We cannot, and let us remark also, that the greater 
part of these phenomena, which begin as it were, and 
terminate the organic life, are connected with motions 
essentially voluntary, and in consequence, under the 
dominion of the animal life. 

I shall not here enlarge on the numerous modifications 
of power, taste, and desire, which have their source in 
habit I refer to the numerous works which have con- 
sidered its influence in a difierent point of view from that 
which I have indicated. 



54 PHYSIOLOGICAL RESEARCHES 



CHAPTER VI. 

G£X£BAL DIFFERENCES OF THE TWO LIVES- WITH RESPECT 

TO MENTAL AFFECTION. 

It is necessary toeonsider^ ander two relations, those 
acts, which little connected with the matçrial organiza- 
tion of animals, are derived from this principle so little 
known in its nature, but so remarkable as to its effects, the 
centre of all their voluntary motions, and on the subject 
of which, there would have been less dispute, if philoso- 
phers, instead of attempting to reach its essence, had beea 
contented with analyzing its operations. These actions, 
which we shall consider more especially in man,^ with 
whom they are the most perfect, are either purely intel- 
lectual, and relative to the understanding only ; or they 
are the immediate product of the passions. Examined 
under the first point of view, they are the exclusive attri- 
bute of the animal, under the second of the organic life. 

I. Whatever relates to the understanding belongs to 

the animal life. 

It would be useless for me to insist on proving that 
meditation, reflection, the judgment, and all the opera- 
tions of the mind depending upon an association of ideas, 
are under the dominion of the ahfmal life. We judge 
from impressions formerly or actually received, or from 
those which we ourselves create. Perception, memory, 
and the imagination are the principal bases, on which are 
founded the operations of the mind, but these very bases 
themselves repose upon the action of the senses. 



ON LIFE AND DEATH. 55 

Let us suppose a man at his birth to be deprived of all 
th9t exterior apparatus, which is destined to establish his 
connexions with surrounding objects; such man will not 
altogether be the statue of Condillac, because, as we shall 
see hereafter, other causes besides the sensations, maj 
occasion within him the motions of the animal life ; but 
at least will he not be able, a stranger as he is to every 
thing surrounding him, to form any judgment with respect 
to things» The intellectual functions with him will be 
null ; volition, which «is the consequence of these func- 
tions, will not have place, and consequently, that very 
extensive class of motions which has its immediate seat 
in the brain, and which itself is but an effect of the 
impressions made there, will in nowise belong to him. 

It is by means of the animal life that man is so great^ 
80 superior to the beings, which surround him ; by means 
of this that he possesses the sciences, the arts, and every 
thing which places him at a distance from the gross 
elements under which we represent brute matter; by this 
that he approaches spirituality; for industry and com- 
merce, and whatever enlarges the narrow circle within 
which the.e£forts of other animals are confined, are exclu- 
sively under the dominion of the animal life of man. 

The actual state of society then is nothing but a more 
regular development, a more marked perfection of the 
exercise of the different functions of this life ; for one of 
its greatest characters as I shall hereafter prove, consists 
in its capability of being unfolded, while, in the organic 
life, there does not exist a part, which in the least degree 
may pass the limits which are set to it by nature. We 
live organically in as perfect, in as regular a way, when 
inCEUits» as when men ; but what is the animal . life of the 
child compared with that of the man of thirty years of 
age ? 



56 PHTSIOLOOICAL RESEARCHES 

We maj conclude that the brain, the central' organ of 
the animal life, is the centre of whatever relates to the 
understanding. I might here proceed to speak of its 
volume in man, and in animals, whose intelligence appears 
to decrease in proportion as the facial angle is diminish- 
ed, and expatiate upon the different alterations of which 
the cerebral cavity is the seat, as well as on the disorders 
of the intellectual functions arising thence. But these 
things are all of them well enough understood. Let us 
pass to that order of phenomena, *which though as foreign 
as the preceding to the ideas which we form of material 
appearances, are elsewhere seated. 

II. Whatever relates to the passions belongs to the 

organic life, 

m 

My present object is not to consider the passions 
metaphysically. It little matters, whether they be all of 
them the modifications of a single passion, or dependent 
each of them upon a separate principle. We shall only 
remark, that many physicians in discussing their influ- 
ence on ' the organic phenomena, have not sufficiently 
distinguished them from the sensations ; the latter are the 
occasion of the passions, but differ from them widely. 

It is true that anger, joy, and sorrow, would not affect 
us, were we not to find their causes in our connexions 
with external objects. It is true also, that the senses are 
the agents of these relations, that they communicate the 
causes of the passions, but in this they act as simple 
conductors only, and have nothing in common with the 
affections, which they produce ; for sensation of every 
kind has its centre in the brain, sensation of every kind 
supposing impression and perception. If the action of 
the brain be suspended, sensation ceases 3 on the contrary^ 






<* 



ON LIFE AND DEATH. 57 

the brain is never affected by the passions ; their seat is 
in the organs of the internal life.* 

It is undoubtedly surprising that the passions, essen^^ 
tially as they enter into our relations with the beings 
which are placed about us^ that modifying as they do at 
every moment these relations, that animating, enlarging, 
and exalting the phenomena of the animal life, which 
without them would be nothing but a cold series of intel-* 

• 

* Bicbat, ia this paragraph, seems to say that the perceptions, which 
produce in us the passions, go direcllj and without the intervention of 
the brain, from the scuiees to the organs which he supposes to be affected 
by them. We cannot believe that such was his idea. The paragraph 
which follows mast aid us in understanding it, afnd we shall endeavour 
to elucidate it by means of an example. 

A certain event happens ; a man 19 informed of it by means of his 
tenses ; he examines the event in itself, and its relations with antecedent 
and future events ; his judgment weighs the various consequences of it, 
and shows them to be very disadvantageous to him. Here, as Bichat callt 
it, IB a cold series of intellectual phenomena, which would .take place 
in the individual, whoever the man may be who is affected by the event 
to which he has given his attention. It is found that the man who Is 
injured is himself; then, from a knowledge of this only, his heart is 
fympathetioally affected; its motions become' more rapid and stronger, 
they send to the brain a gi'eater quantity of blood, and this increase of 
habitual excitement in the organ of thought, produoei a kind of mental 
attention in relation to the 'event that has taken place* 

Thus, without the part that thé heart has taken in it, this man would 
have seen with the most perfect indifference an event most disastrous 
to himself; for without even supposing anger, the least sentiment of 
sadness being a passion, we cannot believe that he is affected with it, 
if his liver, stomach or spleen are not at the montent in a particular 
state. Biit does not every thing on the contrary lead us to believe that 
anger exists before the agitation of the heart, and that this is the eflëct 
of it and not the cause ? This agitation of the heart without doubt, by 
sending to the brain a greater quantity of blood than usual, contributes 
in its turn to develop and support the kind of alienation which accom^ 
panics anger ; but it is necessary that the passion should already exist, 
since a favourable event, by producing ai rapid motions of the heart, 
will produce nothing similar. 

8 



58 PHYSIOLOLQGICAL RESCA&CHES 

lectual movements ; it is astonishing^ I say, that the 
passions should neithet* have their end, nor beginning 
in the organs of this life, but on the contrary, that the 
parts whieh serve for the internal functions, should be 
constantly affected by them, and even occasion thtem 
according to the state in which they are found. Such 
notwithstanding is the result of the strictest observatien. 

I shall first observe, that the effect of every kind of 
passion is at all times to produce some change in the 
organic life. I Anger accelerates the circulation of the 
blood, it multiplies the efforts of the heart The passion 
of joy has not indeed so marked an influence upon the 
circulation, but alters it notwithstanding, and carries it 
lightly towards the skin. Terror acts inversely; this 
passion being characterized by a feebleness in. the vascular 
system, a feebleness, which in hindering the blood fW>m 
arriving at the capillary vessels, occasions the paleness 
which at such time is so particularly remarked. The 
effects of sadness and sorrow are nearly analagous. 

So great indeed is the effect which the passions occa- 
sion upon the organs of the circulation, as even to arrest 
them altogether in their functions, where tbé affection is 
very powerful. In this way is syncope produced, for the 
primitive seat of syncope is always, as I shall soon prove 
it to be, in the heart, and not in the brain. In this the 
latter organ ceases to act, only because it ceases to receive 
the excitant necessary to its action. Hence also may bap- 
pen death itself, the sometimes sudden effect of extreme 
emotion, whether such emotion as in anger so far exalts 
and exhausts the powers of the circulation, as not to leave 
them any further excitability, or whether as in the death 
occasioned by excessive grief, the powers at ence exces- 
sively debilitated, are no longer capable of returning to 
their usual condition. 



ON LIFE AND DEATH. 59 

If the total and instantaneous cessation of the circula* 
tion be not occasioned by this debility, a variety of lesions 
in the blood vessels may be, notwithstanding, the effect 
of it. Desault has remarked that diseases of the heart, 
and aneurisms of the aorta, were augmented in number 
during the revolution, in proportion to the evils which it 
produced. 

Nor does respiration depend less immediately upon 
the passions ; that oppression, that anxiety, and sense of 
suffocation, which is the sudden effect of profound sorrow, 
must imply in the lungs a remarkable change and sudden 
alteratian. In that very long series of chronic or acute 
affections, the sad attribute of the pulmonary system, 
must we not often look to the passions to find the princi- 
ple of the disease ? . , 

And that lively sensation at the pylorus under strong 
emotion, that ineffaceable impression which sometimes 
remains there, from whence succeed the schirri of which 
it is the seat, that sentiment of stricture, as it were, 
about the stomach, about the cordia in particular; under 
other circumstances those spasmodic vomitings^ which 
sometimes follow the loss of a beloved object, the new9 
of a fatal accident, or any kind of trouble, the cause of 
whkh -are the passions ; that sudden interruption of the 
digestive phenomena either in Consequence of agreea- 
ble or disagreeable news, those afiections of the bowels, 
thoàe organic lesions of the intestines, of the spleen 
observed in cases of melancholy, or hypochondria, dis- 
eases which are always preceded by sad forebodings and 
the darker affections of the mind ; do not all these indicate 
the very strict connexion of the digestive viscera with 
the state of the passions ? 

They do; and the secreting organs have not a less 
connexion with them. Sudden fear suspends the course 



\ 



60 PHYSIOLOGICAL RESEARCHES 

of the bile^ and is the oecasion of jaundice; sudden 
anger is often the origin of bilious fever. In a state of 
sorrow or joy, sometimes even in that of admiration, our 
tears flow abundantly: the pancreas is not less frequently 
affected in hypochondria. 

But the functions of the circulation, of dis^estion, respi- 
ration and secretion, are those which are most directly 
under the influence of the passions ; those of exhalation^ 
absorption and nutrition appear to be less so. • Doubtless, 
the reason of this is, that these functions have Dot as the 
former any principal focus, or essential viscera, the state 
of which may be compared with that of the mind. Their 
phenomena disseminated throughout all the organs belong 
exclusively to none, and cannot be observed as well as 
those, the effects of which are confined within a narrow 
compass. 

Nevertheless, the alterations, which these functions 
experieiice are not less real, do not become less apparent 
after a certain Ume; let the man, whose hours are marked 
by sorrow, bé compared with him, who lives in peace of 
mind, and the difierence of the process of nutrition in 
the one and in the other will easily be seen. 

Let us, for a moment, approximate the times, when the 
terrible passions of sorrow, of fear and revenge seemed 
to brood over our country, and those, when safety and 
abundance continually supplied us with the gayer ones so 
natural to us ; we may then recall what at the two periods 
were the outward appearances of our countrymen, and 
appreciate the influence of the passions on the process of 
nutrition. The very expressions which are continually 
in our mouths that such a one is dried up with envy, 
preyed upon by remorse, consumed and wasted away 
with sorrow, do not even these announce how much the 
nutritive functions are modified by the passions ? 



1 

« 



ON LIFE AND DEATH. 61 

I know not for what reason the powers of absorption 
and exhalation should not be subject to the same influence, 
though they appear to be less so ; may not dropsies, find 
all infiltrations of the cellular membrane, the peculiar 
Tices of these two functions, depend on mental affection ? 

In the midst of these disturbances, of these partial or 
general revolutions which are produced by the passions 
in the organic phenomena, let us consider the actions of 
the animal* life ; they constantly remain unaltered, or if 
they- do experience any derangement, such derangement 
has ever its source in the internal functions. 

From so many considerations we may conclude that it 
is upon the organic and not upon the. animal life that the 
passions exercise their influence. Accôrdiqgly, whatever 
serves to paint them must relate to the former. Of this 
assertion, our gestures which are the mute expressions 
both of the sentiment and understanding are a remarkable 
proof. Thus if we indicate any operation of the memory, 
imagination or judgment, the band is carried to the head; 
do we wish to express either love or hatred, or joy or 
sorrow, it is to the seat oFthe heart, the stomach or intes* 
tines, that it is then directed. 

The actor, who should mistake in this respect, who in 
speaking of sorrow should refer his gestures to his head, 
or, carry them to his heart, for the purpose of announcing 
an effort of genius, would be ridiculed for a reason which 
we should better fSeel than comprehend. 

The very language of the vulgar, at a time when the 
learned referred to the brain, as the seat of the soul, 
affections of all kinds, distinguished the respective attri* 
butes of the two lives. We have always said a strong 
head, a head well organized to denote perfection of mind; 
a good heart, a sensible heart, to indicate proper feeling. 
The expressions of fury circulating in the veins, and 



6âS PHYSIOLOGICAL RESEARCHES 

atirring up the bile ; of joy making the heart leap, of 
jealousy distilling its passions into the heart, are by no 
means poetical expressions, but the enunciation of that 
which actually takes place in nature. In this way do all 
these expressions, the language of the internal functions 
enter into our poetry, tehich in consequence is the 
langui^ of the passions or the organic life, as ordinary 
speech, is that of the understanding or the animal life. 
Declamation holds a middle place between the two, and 
animates the cold language of the brain by the expressive 
language of the inward organs. 

I shall even venture to assert that anger and love 
kioenlate, if I may so express mjrself, into the humourt, 
into the saliva, particularly, a radical vice, which renders 
dangerous the bite of animals at such times ^ for thepe 
passions do really distil into the fluids a poison, as we 
indicate the fact by our common expressions. The 
violent passions of the nurse have frequently given her 
milk a pernicious quality, from whence disease has fol- 
lowed to the child; and in the same way shall we explain 
from the modifications which 'the blood of the mother 
receives under strong emotion, the manner, in which 
these emotions operate on the nutrition, the conforma- 
tion, and even on the life of the fœtus. And not only 
do the passions essentially influence the organic func- 
tions, in affecting their respective viscera, but the state 
of these viscera, their lesions, the Variation of their forces 
concur in a decided way to the production of the passions 
themselves. Their relations with age and temperament^ 
establish incontestably this fact. 

Who does not know for instance, that the individual 
of the sanguine temperament, whose expansion of lungs 
is great, whose circulatory system is large and strong; 
who does not know that such a man is possessed of a 



ON LIF£ AND DEATH. 63 

clisposition to Anger and Tiolence ? that when the bilious 
system prevails, the passions of enry and hatred are 
more particularly developed ? that when the lymphatic 
system is pronounced , are pronounced also the inactivity 
and dulness of the individual? 

In generaLthat which characterises any particular tem- 
peramenty con^sts in a correspondent modification on one 
hand of the passions^- and *on the other of the state of 
the organic viscera. The animal life is almost always a 
stranger to the attributes of the temperaments. 
• The same may be. said of age ; the weakness of the 
organization of the child coincides with his timidity. 
The developihent of the pulmonary and vascular system, 
with the courage and temerity of the youth ; that of the 
liver, and the gastric system with the envy, ambition and 
intrigue of manhood. 

In considering the passions as affected by climate and 
season, the same relations are observed between them 
and the organic functions; but physicians haVe sufficiently 
noticed these analogies, and it would be useless to repeat 
them. 

At present, if from man in a state of health, we look 
.to man in a state of disease, we shall see that the lesions 
of the liver, of the stomach, of the spleen, the intestines 
and heart produce a variety of alterations in our affections, 
which all of them cease together with their causes. 

The ancients, better than our modern mechanieians, 
then were acquainted' with the laws of the economy, 
in supposing that our bad affections were evacuated by 
purgatives, together with the noxious humours of the 
body. By disembarrassing the prime vise they got rid 
of these affections. In* fact how dark a tint does the 
fulness of the gastric viscera cast upon the countenance ! 
the em»i of the first physicians on the subject of the 



64 PHTSIOLOOICAL RESEARCHES 

atrabiiisy were a proof of the precision of their observa- 
tioDs on the connexion of these organs with the state of 
the mind. 

In this way every thing tends to prove» that the organic 
life, is the term, in which the passions end, and the centre 
from whence they originate. But we shall be asked 
perhaps, why vegetables, which live organically, do not 
offer any vestige of them ? the reason seems to be, that 
besides their want of the natural excitants of the passions, 
namely the external apparatus of the senses, they are 
wanting also in those internal organs, which concur most 
especially to their production, such as the digestive 
system, that of the general circulation, and that of the 
great secretions, which are remarked in animals. 

Such are the reasops also why the passions are so 
obscure in the Zoophytes, in worms, &c. and why in 
proportion as the organic life becomes more simple in 
the series of animals, and loses its important viscera, the 
passions are less observable. 

III. 7%e passions modify the actions of the animaJ 
life though seated in the organic life. 

Although the passions . are the especial attributes of 
the organic life, they nevertheless exert an influence over 
the animal life, which it is necessary to examine. The 
muscles of volition are frequently brought into play, and 
their actions sometimes exalted, Sometimes lowered by 
them ; the strength for instance of the man in anger is 
doubled, and tripled ; is exercised with an energy^ of 
which he is not himself the master. The source of this 
augmented power is manifestly it the heart 

This organ, as I shall prove hereafter, is the natural 
excitant of the brain, by means of the blood, which it 



ON LIFE AND DEATH. 65 

sends thither. The energy of the cerebral action is in 
proportion to the energy of the stimulus applied to it, and 
we hav^ seen that the effect of anger is to impress a great 
vivacity upon the circulation ; hence, a larger quantity of 
blood than usual is. thrown upon the forain in a given time. 
The consequence is an effect analogous to that which 
happens in the paroxysm of ardent fever^ or the immode- 
rate use of* wine. * • ' 

It is then, that the brain being excited strongly, excites 
as strongly the muscles which are submitted to its influ- 
ence ; accordingly their motions must be involuntary, for 
the will is a stranger tp those spasms, which are determin- 
ed "by a cause which irritates the niedullary organ. Such 
cause may be a splinter of bone, blood*, pi^s, the handle 
of a scalptl as in oiir experiments ; in short of various 
kinds. 

The analogy is exact, the blood being transmitted to 
the brain' in greater quantity than usual, produces upon 
it the effect of the different excitants above mentioned. 
In these different motions then, the brain is passive ; it 
engenders indeed at all times the necessary irradiations 
for producing such motion^, but these irradiations in the 
present instance are not the effect of the will. 

It may be observed also, that under the influence of 
anger, a constant relation exists between the contractions 
of the heart and the locomotive organs; they both increase 
at the same time, and at the same time resume their equi- 
librium. In every other case on the contrary there is 
no appearance of this relation ; the action of the heart is 
uniformly the same, whatever the affection of the muscu- 
lar system. In convulsion and palsy, the circulation is 
neither impeded nor accelerated. 

In the passion of anger, in fact, we see the very mode 
of the influence, which the organic life exercises over the 



ê^ PIIVSIOLOGICAL RE&EAIK:HE8 

mimai life. In the passion of fear also, where on the one 
hand the enfeebled heart directs a less quantity of blood, 
and consequently a smaller cause of excitement Ur th» 
brain, and .where on the other hand a debility may bt 
observed in the external muscles, we may perceive tbm 
connexion of cause and effect. This passion offers in the 
first degree the phenomenon, which in the last degree it 
shewn by those lively emotions, which suspending alto* 
gether the efforts of the heart, occasion a sudden cessation 
of the animal life and syncope. 

But in what way shall we account for those modifica- 
tions of the motions of the animal life, which are the 
effect of the passions ? In what way shall we explaih 
the cause of those infinite varieties, which succeed each 
other in the moveable picture of the face ? 

All the muscles which are the agents of these motions 
receive their nerves from the brain and tie under the 
influence of the will. What is the reason then, that 
when acted on by the passions, they cease to do so, and 
enter under the class of (hose motions of the organic life>. 
which are put forth without our direction or conscious- 
ness. The following if I mistake not is the best explansi- 
tion of the fact. 

The most numerous sympathies exist between the 
internal viscera, and the brain or its different parts. 
!Every step which we make in practice presents us with 
affections of the brain originating sympathetically from 
those of the liver, stomach and intestines. Now as the 
effect of every kind of passion is to produce a change of 
power in one or the other of these viscera, such change 
will sympathetically excite either the whole of the brain 
or some of its parts, whose re-action upon the muscles, 
which receive from thence their nerves, will produce the 
motions^ which are then observed. In the productioïi 'of 



ON LIFE AND DEATH. 6? 

Ifhese motions the cerebral organ accordingly must be pas* 
dye, it is active oqI^ when the' will presides over its efforts. 

The effects indeed of the passions are similar to those 
diseases of the internal organs^ which by sympathy are 
the eacufes of atony, palsy, and spasm. 

3ut perhaps the inward organs ^ct upon the voluntary 
musclesi not by means of the immediate excitement of 
the brain^ but by direct nervous communication. Of 
what importance to us is the manfter ? We are not at 
present occupied on the so much agitated question of the 
manner of sympathetie communication. 

The essential thing is the fact itself. Now in this fact, 
there are two things evident ; the affection of an internal 
organ by the passions, ana secondly a motion produced 
in consequence of such affection in muscles, on which 
tiiis organ in the common series of the phenomena of 
the two lives has no kind of influence^ This is surely ^ 
sjrmpathy, for between it, and those with which convul- 
sion, or spasm of the face present uà, when occasioned 
by any lesion of the phrenic centre, or the stomach, the 
difference is only in the cause, which affects the internal 
organ. 

Any irritation of the uvula, or the pharynx con- 
vulsively agitates the diaphragm. The too frequently 
repeated use of fermented liquors occasions a general 
trembling of the body. But that which happens in one 
mode of gastric affection, may happen in another. What 
matters it, whether the stomach or liver be irritated by 
passion or by some material cause ? It is from the^ affec- 
tion, and not from- the cause of the affection that results 
the sympathy. 

Such in general is the manner in which the passions 
withdraw from the empire of the will, those motions 
which by nature are voluntary^ Such is the manner in 



63 PHYSIOLOGICAL RESEARCHES 

which they appropriate to themseWes, if I may so 
express myself, the phenomena of the 'animal life, though 
they possess their seat essentially in the organic life. 

When very strong, the very lively affection of the 
internal organs produces so impetuously the sympathetie 
motions of the muscles, that the action of the brain ' is 
absplutely null upon them ; but the first impression pasty 
the ordinary mode of locomotion returns. 

A man is informed *by letter and in presence of com- 
pany, of a piece of news, which it is his interest to 
conceal. All on a sudden his brows become contracted, 
he grows pale, and his features are moulded according to 
the nature of the passion, which has been excited. These 
are sympathetic phenomena produced by the abdominal 
viscera which have been affected by the passions* and 
which in consequence belong to the organic life. But ia 
a short time the man is capable of putting a constraint 
upon himself, his countenance clears up, his colour 
returns. Meanwhile the interior sentiment continues to 
subsist however, but the voluntary have overpowered the 
sympathetic motions, the action of the brain has sur- 
mounted that of the stomach or the liver; the animal 
life of the man has resumed its empire. 

In almost all the passions the movements of the animal 
life are mingled with those of the organic life, or succeed 
to them ; in almost all the passions, the muscular action 
is in part directed by the brain, in part by the organic 
viscera. The two centres alternately overpow:ered the 
one by the other, or remaining in a state of equilibrium, 
constitute by the modifications of their induence, those 
numerous varieties which are seen in our mental affections. 

And not only on the brain, but on all the other parts 
of the body also do the viscera affected by the passions 
exercise their sympathetic influence. Fear affects th» 



ON LIFE AND DEATH. 69 

stomaeh in the ûtst place, as is proved by the sense of 
stricture felt there at such time.* But when thus affect- 
ed, the organ re-acts upon theskin^ with which it has so 
strict a connexion, and the skin immediately becomes the 
seat of the cold and sudden sweat, which is then so often 
fejl^t* This sweat is still however of the same nature with 
that which is occasioned by tea, or warm liquids. Thus 
a glass of cold water, or a current of cold air, Will sup- 
press this excretion by means of the relation, which 
exists between the skin, and the mucous surfaces of the 
stomach or bronchiae. We must carefully distinguish 
between sympathetic sweating, and that, of which the 
cause is directly made upon the skin. 

Hence though tbe brain be not the only term of the 
re-action of the internal viscera v\^iich are affected by 
the passions, it is nevertheless the principal one, and in 
this respect may always be considered as a focus at all 
times in opposition to that which is centered in the inter- 
nal organs. 

IV. 0/ the epigastric asntre.^^It does not exist in the 
sense, whick ^authors hcwe pretended. 

Authors have never been at variance with respect to 
the cerebral focus. The voluntary motions have ever 

^ There is no proof that the seme of itricture which ii felt in the 
epigastric region, is connected with I he stomach ; and if it were proved 
that it was so, it would not follow froii\ it that this organ was primarily 
affected from fear. The same passion sometimes acts differently in 
different individuals ; there are some who 80 not feel this stricture in 
the epigastric region, but who are deprived of the use of their legs ; 
must it be said that in these individuals the seat of fear is in the 
extensor muscles of the legs ? If the introduction of a warm drink 
into the stomach produces an increase of cutaneous exhalation, should 
we conclude from analogy, that it is by acting primarily upon this organ 
that fear causes that cold sweat which sometimes accompanies it? 



. I 



71 PHTSIOLOGICAL RESEARCHES 

been regarded as an effect of its irradiations. Tbey do 
not equally agree upon the subject of the epigastric focus; 
some of them place it in the diaphn^m, others in the 
pylorus, others in the plexus of the great sympathetic 
nerve.* 



* JVb/« hy the JivUhor. — This nerroas netwoilc, ^ing priDcipaDj fc 
the temi-laDar ganglion, belongs to almost the whole abdominal Ti 
lar sjstem^ whose Yarioas ramificatiens it follows. It is, according to 
the usual manner of considering it, one of the divisions of the great 
sympathetic ; bat it seems to me that the ideas of anatomists respecting 
this important nerve are not conformable to nature. 

Every one considers it as a medullary cord, extending from the bead 
to the sacrum, sending in its course various ramifications to the necki 
the thorax and the abdomen, following in its distributions a comaa 
analogous to those nerves of the spine, and deriving its origin fromtbotf 
nerves, according to some, and from those of the brain, according to 
others. Whatever be the name by which it is designated, sympathetic, 
ioteicostal, &c. ; the manner of describing it is always the same. 

I believe that this manner is altogether wrong, that there really existe 
no nerve analogous to the one designated by these words, and that 
what is taken for a nerve is only a series of communications betwoea 
different nervous centres, placed at different distances from ea<:fa other. 

These nervous centres are the ganglions, scattered throughoat tbt 
different regions, they have all an independent and insulated actign» 
Each is a particular centre which 'sends in various directions aiaoj 
ramifications, which carry to their respective organs the irradiations of 
the centre from which they go ofiL Among these ramifications, some 
go from one ganglion to another ; and as these branches which unite 
the ganglions form by their union a kind of continuous cord, this baa 
been considered as a distinct nerve ; but these branches are only com- 
munications, simple anastomoses, and not a nerve analogous to the 
others. 

This is so true, 4hat these con^onications are oflen interropted* 
There are subjects, for example, in whom is found a very distinct 
interval between the pectoral and lumbar portions of what is called the 
great sympathetic, which seems to be cut off in this place. I have seen 
this pretended nerve cease and afterwards reappear, either in the lumbar 
or sacral region. Who does not know that eometimes a single branchy 
sometimes many go from one ganglion to another, especially between 
the last cervical and the first dorsal ; .thai the.size of these branches 



ON Lira AND DEATH. 71 

But on this point, they appear to me to be all of thena 
in the wrong. They assimilate or rather identify the 
second with the first focus — ^they think, that the passions, 
as well as the sensations have their seat in an invariable 

Taries remarkably; and that affer having famished manj divisions, the 
i^pmpathetic is larger than before it gave off atiy ? 

These considerations evidently prove that the commnnicating1>ranches 
of the ganglions no ntore suppose a continuons nerve than the branches 
which go from each of the cervical, lumbar or sacral pair to thç two 
pair which are superior and inferior to them. In fact, Aotwithstanding 
these communications, we consider each pair in à separate manner, and 
do not regard their union as a nerve. 

It is necessary to describe in the same Way separately each ganglion, 
and the branches which go off from it. ■ 

Hence I shall divide hereafter in my descriptions, in which I have 
hitherto, pursued the ordinary course, the nerves into two great systems, 
one arising from the brain, and the other from the ganglions; the first 
^ has a single centre, the second has a great number of them. 

1 shall first examine the divisions of the cerebral system ; I shall 
afterwards treat of the system of the ganglions, which . may be subdi- 
vided into those of the head, the neck, the thorax, the abdomen and 
the pelvis. 

In the head is found 'the lenticular ganglion, that of Meckel, that of 
the sublingual gland, .&c. êio. Though no communication connects 
these different centres, either together or with the pretended great 
sympathetic, yet their description belongs to that of the nerves of which 
this is the connecting link» as the communica|ions are, arrangements 
merely .accidental to this system of nerves. 

In the neck there are the three cervical ganglions, sometimes another 
upon the side of the trachea, in the thorax the twelve thoracic, in the 
abdomen the semi-ltinar, the lumbar, &c. and in the pelvis, the sacral ; .< 
these are the différent centres whose ramifications it is necessary to 
examine separately, as we do those of the cerebral centre. 

For example, I shall first describe the semi-lunar ganglion, as we do 
the brain ; then I shall examine the branches, among which, is that by . 
which it cqjnmunicates ^rith the thoracic ganglions, that is to say, the . 
great ' splanchnic ; for it is very incorrect to consider this nerve as 
giving origin to the ganglion. In the same wa^, in the neck and the 
head, each ganglion will be first described ; then I shall treat of its 
branches, among which are those of commun ications^ The «iraiu^ 



72 PHYSIOLOGICAL RESEARCHES 

centre. That, which has led them to this opinion lias 
been Ihe sentimeht of oppression, which is felt at the 
cardia under all painful affection. 

But it is to be remarked, that in the internal organs, 
the sentiment produced by the affection of a part is always 
an unfaithful index of the seat and extent of such affection. 

ment being nearly the iame for the jçanglions of the thorax, the pelvis 
and the loins, the description of each region will be similar. 

This manner of describing the nerres, by placing an evident line of 
demarcation between the two systems, exhibits thèse two. systems such 
as they really are in nature. 

What anatomist, in fact, has not been stmck with the differences 
that exist between the nerves of these two systems ? Those of the 
brain are larger, less numerous, whiter, more compact in their textare 
and exhibit less variety. On the contrary, the extreme tenuity, great 
number, especially towards the plexuses, greyish colour, remarkable 
softness of texture and varieties extremely common are characters of 
the nerves coming from the ganglions, if we except those of commani- 
cation with the cerebral nerves and some of those which unite together 
these small nervous centres. 

Besides, this division of the general system of the nerves into two 
secondary ones, accords very well with that of life. We know in fact 
that the external functions, the sensations, locomotion and the Toice 
are all dependent on the cerebral nervous system ; that on the contrary, 
most of the organs which perform the internal functions derive from 
the ganglions their nerves, and witt^ them the principle of their action. 
We know that animal sensibility and contractility arise from the first, 
and that where the second alone are found, there is only organic sensi- 
bility and contractility. 

I have said that the termination of this kind of sensibility and the 
origin of the corresponding contractility are in the organ in which they 
are noticed ; but perhaps both the termination and origin are more 
remote, and are in the ganglion from which the organ receives its* nerves, 
as the termination of animal sensibility and the origin of the contractility 
of the same species are always in the brain. K it be so, as the ganglions 
are very numerous, we can understand why the forces of organic life 
do not refer, like those of animal life, to a common centre. 

It is evident from these considerations, that there is no great sympa- 
thetic nerve, and that what has been designated by this word is only an 



ON LIFE AND DEATH. 73 

For example, hunger must undoubtedly affect the whole 
of the stomach, but the sensation of hunger is tr nsmitted 
to us only by the cardia. A large inflamed surface in 
the pleura for the most part gives rise to a pain, which is 
felt only in a point. How often does it happen that in 
the head or the abdomen a pain which is referred but to 
a very limited space coincides with a largely disseminated 
affection, with an affection possessing even a different seat 
from that which is presumed. We should never consider 
the place to which we refer the sentiment as a sure index 
of that which the affection occupies, but only as a sign 
that it exists either there or thereabouts. 

From all this it follows, that to form a judgment of the 
organ, to which such or such a passion relates, we ought 
to recur to the effect produced in the functions of the 
organ by the influence of the passion, and not to the feel- 
ings of the patient. In setting out from this principle it 
will be easy to see, that it is sometimes the stomach 
and alimentary canal, sometimes the sanguiferous system, 
sometimes the viscera belonging to the secretions which 
experience a change. 

asiemblage of small nenrous sjatenu, with distinct fanctions, bot with 
commanicating branches. 

V^e see then what should be thoaght of the disputes of anatomists 
respecting the origin of this pretended nerve, placed in the fifth, sixth 
pair, &c. in those of the neck, back, &c. 

Manj physiologists haye entertained concerning the ganglions opin- 
ions similar to those which I have now offered, bj considering these 
bodies as small brains ; but it is essential that these opinions should 
enter into the description, which, as it is now jnade, gives a very inac- 
curate idea both of these nervous centres and of the nerves which go 
off from them. 

The expression of nervous branehet ginng origin to tueh or tuch a 
ganglion^ &c. resembles that in which we should consider the brain as 
arising from the nerves of which it is itself the origin. 

10 



74 PHYSIOLOGICAL RESEARCHES 

I shall not repeat the proofs of this assertion, but sup- 
posing it to be demonstrated, I shall assert that there does- 
not exist for the passions as there does for the sensations 
a fixed and constant centre ; that on the contrary the 
liver, the lungs, the spleen, the stomach, and the heart, 
are turn by turn afibcted, and at such time form that 
epigastric centre so celebrated in modern works ; and if 
in general we refer to this region the sensible impression 
of all our afiections, the reason is that all the important 
yiscera of the organic life, are there concentrated. In 
fact, if nature had separated these viscera, had the liver 
for instance been placed in the pelvis, and the stomach in 
the neck, the heart and spleen remaining as they now - 
are seated, in such case the epigastric focus would disap- 
pear, and the local sentiment of our passions vary accord- 
ing to the part affected. 

In determining the facial angle, Camper has thrown 
much light upon the proportion of intelligence enjoyed 
by the several classes of animals. It appears that not 
only the functions of the brain, but that all those of the 
animal life which are centred there, have this angle for 
the measure of their perfection. 

It would be a very pleasing thing could we indicate in 
the same way a measure, which assumed from the organs 
of the internal life, might fix the rank of each species 
with regard to the passions. The dog is much more 
susceptible than other animals of the sentiments of grati- 
tude, of joy, of sorrow, of hatred, and of friendship ; has 
he any thing more perfect in his organic life? the monkey 
astonishes us by his industry, his disposition to imitatei 
and by his intelligence ; his animal life is certainly supe- 
rior to that of every other species. Other animals, such 
as the elephant, interest us by their attachment, their 
affection, their passions ; they delight us also with their 






ON LIFE AND DEATH. 95 

lively sensation of pain is the result.* I have established 
this fact by a number of experiments in my treatise on 
the membranes. The following; is another of the same 
kind, which i have since observed. The parietes of the 
arteries as we know are sensible to the blood by which 
they are traversed, but at the same time are the term of 
this sentiment. If a fluid, however, which is foreign to 
this system, be injected into it, the anioial will immedi- 
ately discover by his cries, that he is sensible of the 
presence of such fluid.! 

We have seen that it is a property of habit, to weaken 
the sentiment, to transform into indifferent sensations all 
those of pleasure, or of pain. Foreign bodies, for example, 
will make upon the mucous membranes a painful impres- 
sion during the first days of their application to it ; they 
develop in such parts the animal sensibility, but by little 
and little this sensibility decreases, and the organic alone 
subsists. In this way the urethra is sensible of the bougie 

* The idea of endowing each texture with a peculiar kind of sensi- 
bilitj in relation with its uses is one which pleases the imagination. 
The ligaments are designed to oppose the separation of the bones ; thej 
should remain insensible to everj kind of stimulus that does not tend 
to disunite these parts, and pain consequently» should not be produced 
but from distension or twisting. Unfortunately this supposition is not 
well founded, the facts on which it rests were not accurately obser?ed. 
It is very true that in twisting these ligaments, the animal almost always 
cries out, but it is because we at the same time stretch some neighbour- 
ing parts endowed with sensibility. When this is prevented and the 
experiment is made with proper precaution, we ran twibt, distend or 
tear the ligament, without appearing to give the animal any pain. 

t So, as long as the fluid is retained in the artery, which is easily done 
by means of ligatures, no pain is manifested ; but when the irritating 
substance b carried by the vessels to the heart or to any other sensible 
part, we can easily conceive that the animal must experience pain, for 
the irritant always produces its efifect, whether it be carried directly to 
the part or irriTe there by means of the circulation. 



86 i IIYSIOLOGICAL RKSCARCUES 

as long as it continues there, for during the whole of such 
time, the action of the mucous glands of the passage is 
augmented, from whence arises a species of catarrh, but 
the individual for the first moments only had a painful 
consciousness of the presence of the instrument. 

We every day observe, that inflammation in exalting 
the organic sensibility of a part, transforms the organic 
into the animal' sensibility : the cartilages thus, and the 
serous membranes which in their ordinary state have only 
the obscure sentiment, which is necessary to their nutri- 
tion, in an inflammatory state are possessed of an animal 
sensibility, which is frequently stronger than that of 
the organs to which it is natural. And why ? Because 
the essence of inflammation consists in accumulating the 
powers of the part, and this accumulation suffices for 
changing the mode of the organic sensibility, which 
differs from the animal sensibility in quantity only. 

From these considerations it is evident that the distinc- 
tion above established with respect to sensibility consists 
in the different modifications of which this power is sus- 
ceptible, and not in its nature, which is every where the 
same. This faculty is common to all the organs ; they 
are all of them possessed of it ; it forms their true vital 
character ; but more or less abundantly distributed to 
each, it gives to each a different mode of existence. No 
two parts enjoy it in the same proportion. In these 
varieties there is a degree, above which the brain is the 
term of it, beneath which the organ alone is sensible of 
the impression. 

If to render my ideas on this head more clear I were to 
use a vulgar expression, I should say that distributed in 
such a dose to an organ, sensibility is animal : in such 



ON Lira AND DEATH. 87 

another dote, organic* — ^Now that, which varies the dose 
of aentibilityy is sometimes the order of nature, (in which 
WEjr the skin and the nerves are more sensible than the 
tendons^ and cartilages ;) at other times, disease ; thus in 
doubling the dose of sensibility to the cartilages inflamma- 
tion renders them equal in this respect, and even superior 
to the former, and as a thousand causes may at every 
moment exalt or diminish this power in any part of the 
body it may be changed at every moment from the animal 
to the organic type. Hence the reason, why authors, 
who have made it the object of their experiments, have 
come to results so different; and why some of them have 
observed the periosteum and dura mater to be insensible, 
while others have put themjdown on the contrary as 
endowed with an extreme seniibility. • 

IV. Of the relation which exists between the sensibility 
of each organ, and foreign bodies. 

Although the sensibility of each organ be subject to 
continual variations, it is nevertheless distributed to each 
by nature in a determined quantity ; in a quantity to 
which it ever returns after its alternations of augmenta- 
tion or decreasç. In this respect it resembles the pendu- 
lum, which in each of its different oscillations resumes the 
place to which it is brought down by gravitation. 

* These expreMions <fo«e, «um, quantity of sensibility are incorrect, 
inasmuch as thej exhibit this yital faculty under the same point of view 
as the physical forces, as attraction, for example ; and as they present 
it to us as susceptible of calculation, &c. ; but, from a want of words 
for* one science, it is necessary, in order to make it understood, to 
borrow them from the other sciences. There are expressions, like the 
words to toldery to glue, to ungltte^ &c. that are used for the want of 
others in the osseous system, and which really give very inaccurate 
ideas, unless the mind corrects the sense. 



» 88 PHTSI0L06ICAL RESEARCHES 

It is this determined sum of sensibility, which espe- 
cially composes the life of each organ, and fixes the nature 
of its. relations with foreign bodjes ; in this way the 
ordinary sum of sensibility in the urethra fits it for the 
passage of the urine, but if this sum be augmented, as in 
strong erection of the penis, the above relation ceasQt : 
the canal refuses passage to the urine, and suffers itself to 
be traversed by the semen only, which in its turn has no 
relation with the sensibility of the urethra when the penis 
is not erected.* 

From hence proceeds the reason of the puckering up 
and spasm of the parotid, tlie cystic, and pancreatic ducts» 
as well as of the excreting tubes in general, when the 
molecules of any other fluid than that, which they are 
destined to convey are presented to them. The sum 
of their' sensibility corresponds exactly with the nature of 
their respective fluids, but is disproportioned to that of 
any other.t — ^The spasmodic contraction of the larynx 

* If the urine, during a perfect erection, does not go out of Um 
bladder, it is because the contraction of the muscles of the perineam, 
and especially of the levator ani, prevents it. If these ninsclea are 
relaxed, though the turgescence of the corpus oayemosum and of the 
urethra remains the same, the urine flows out without anj other obstacle 
than what arises from the contraction of the canal produced bj the 
swelling of its parietes. 



t These different excretory ducti do not exhibit in the 
any contractility. There is no stimulus which can produce it in them ; 
I have tried them all in vain. In birds, on the contrary, the ureten 
and the pancreatic and biliary canals are contractile, and their motions^ 
which return at intervals, are too well marked to be mistaken. It 
appears that the contractility of the excretory canals in the abdomeD^ 
is connected in these animals with the absence of the diaphragm.. We 
know in fact that this muscle in the mammalia, assists by the preasure 
which it exerts, the course of the secreted fluids, and renders uteleaa 
the existence of a peculiar motion in the canals which contain them. 
If it be however pretended that this motion exists in them, but that it 



'&:, 



ON LIF£ AND DEATH. BB 

when irritated by any foreign body is produced in the 
«ame manner; for the same reason the ducts, which open 
upon the mucous surfaces, though at all times in contact 
with a variety of different fluids, are never penetrated by 
them.* The mouths of the lacteals, however patulous 
within the alimentary canal, will take up the chyle only, 
they reject the fluids, which are mixed with it ; for with 
these their sensibility has no relation. 

Such relations do not exist only between the different 
sensibility of the organs, and the different fluids of the 
body ; but they may be exercised also between exterior 
substances, and the various parts of the living system. 
The sum of sensibility in the bladder, the kidneys and 
the salivary glands has a peculiar analogy with cantha- 
rides and mercury. It might be thought that the sensi- 
bility of each organ is modified, that it assumes a peculiar 

• 

is insensible, it must be allowed tfa^n, that il cannot perform the office 
which is attributed to it, viz, that of obliterating an opening often large 
enough to admit a quill. It is true, that if the orifice of one of these 
canals be irritated for a long time, a swelling of the membrane which 
lines it is sometimes produced, and the opening is then reallj lessened. 
But in these cases there is no occasion to be deceired ; we see that this 
swelling is produced at that point bj;]the afflux of the fluids, as it would 
be in anj other part subjected to a similar excitement. Besides, it 
should be observed that the obliquity of insertion of the excretory- 
ducts is alone sufficient to explain how the substances which pass in 
front of their orifices are not introduced into them. In fact these 
substances, at the moment of their passage, by the pressure which they 
exert, tend to obliterate the opening of the canal, by flattening its 
parietes against each other ;* it is thus that the pressure of the urine, 
upon the inferior extremity of the ureters, prevents this fluid from 
ascending towards the kidney. The obliteration of the opening is but 
an accidental thing, and most often is not even complete. 

* It is not surprising, that a eanal usually filled with the excreted 
fluids should refuse to admit another which t%Di in an opposite dirao- 
tion. ^ 

12 



n PHYSIOLOGICAL RESEARCHES 

nature, and that it is this diversity of nature, which 
constitutes the difference of the relations of the organs 
with regard to bodies in contact with them ; but a num- 
ber of considerations tend to prove that such difference 
is occasioned, not by any difference in the nature, but in 
that of the sum, the dose, the quantity of the sensibility, 
if such words may be applied to a living property. I 
shall adduce the following instances : — 

The absorbent orifices of the serous surfaces, are some- 
times bathed for months together in the fluid of dropsies, 
and take up nothing. But if the sensibility ' of theae 
orifices be exalted by tonics^ or an effort of nature, in 
such case it will place itself, if I may so say, in eqaili-^ 
brium with the fluid, and absorption will be made. The 
resolution of tumours presents us with the same phe- 
nomena ; as long as the powers of the parts are weakened^ 
the lymphatics refuse admittance to the extra vasated subr 
stances ; but if the sum of these powers be augmentect by 
the use of resolvents, in a short time, from the action of 
the lymphatics, the tumour will disappear : from the aame 
cause the blood, and other fluids are taken up with a sort 
of avidity at times, and at others, not at all.* 

^ All that 18 here said of the sensibilitj of the lymphatic Teitelt, whieh 
makes them sometimes admit and sometimes reject the effused flaidt, ii 
the move hypothetical, as H is not as yet 'proved that these vessels are 
the agents of absorption. It shoald be remarked, tiiat the flitidt that 
are supposed to be absorbed by them, differ efsentially in their chemical 
composition, from the fluid that is usually found in their caritj. This 
fluid besides varies but very lit'Ie in its composition, though its appear* 
ance is not uniformly the same ; now, if it were the result of the 
absorption of fluids differing from each other, its oompositioD oagfat 
also to vary as that of the chyle does, according to the nature of the 
aliments. 

Before the lymphatic vessels were known, the principal phenomena 
of absorption were observed, and it was natural to attribute them to 
the action of the veins. This opinion was maintained for a long t« 






ON LIFE AND DEATH. 9t 

The art of the physiciao, then, in the use of resolvents, 
must consist in ascertaining the degree of sensibility 

«fter the diccoyery of the lymphatioB. Finally, towards the middle of 
the last, centary, Hunter being engaged in examining these yesseb» 
which he has done more to make known than any other man, thought 
that they should be considered as the agents of absorption, and this 
opinion was soon generally admitted. If we look for the means by 
which he overthrew the ancient theory, we are astonished to find that it 
was by five experiments only, Harvey did not with equal facility obtain 
the aoknowledgment of the circulation, and perhaps there does not 
exist a second example of an opinion, which was fera long time 
established, being abandoned so readily. It should be remarked, that 
physiologists had not yet recovered from the surprise produced by the 
discovery of a «ysiem of vessels so extensive, and yet for so long a 
time unknown ; they were impatient to know the use of them ; the 
veins had already the function of returning to the heart the blood 
brought by the arteries; they thought it would not impoverish them 
too much to deprive them of the faculty of absorbing, in order to enrich 
the lymphatics with it. Of the five experiments of Hunter, two are 
designed to prove that the veins do not absorb, the object of the other 
three is to show that the lymphatics do. 

In the first experiment he injected tepid water into a portion of intes- 
tine, and the blood which returned by the vein appeared to be neither 
more diluted nor lighter than before. We cannot conceive how by 
mere inspection^ it is possible io judge if the blood contains a certain 
quantity of absort>ed water, a quantity which must be proportionably 
very small, if we consider the whole amount of blood that passes 
through the mesentric veins during the period necessary for the absorp- 
tion of the fluid. Hunter in the same experiment tied the artery which 
went to the portion of intestine, and examined the state of the vein. 
It did not swell, and its blood did not become aqueous. But after this 
ligature, did the absorption continue to go on in this portion of intestine, 
which -still had no doubt lymphatic vessels ? This the author does not 
say. How moreover should he think that the vein coifld continue its 
action when the artery was tied ? 

In the second experiment Hunter injected milk into a portion of 
intestine, and was unable to discover this fluid in the blood of the 
mesentric veins ; but at the period in which this experiment was made, 
mankind were very far from being able to detect in the blood a very 
•mall quantity of milk, And at the present day, with all the aid derived 






92 PHYSIOLOGICAL RESEARCHES 

which he requires in the vessels for the purpose which 
he has in view; and in exalting or depressing this power 

from chemittrj, we can hardly diiooTer in it a tmall quantity which n 
mixed directly with it. These two experiment! prove then nothing 
against the absorption of the veins ; as to those which he brings forward 
in favour of absorption by the lymphatics, they are not more conclu- 
■ive. I shall content myself with relating one of them. He injected^ 
into a portion of intestine that was empty, a certain quantity of wars 
milk, and confined it there by two ligatures. The veins that camt 
from this portion were emptied of their blood by several punctum 
made in their trunk. The corresponding arteries were tied. He then 
returned the parts into the abdomen, and drew them out again in half 
an hour. Having examined them with attention, he observed that the 
veins were almost empty, and that they contained no white fluid, whilit 
the lacteals were almost full of it. But was not this white fluid that 
fiUed them chyle rather than milk? Was it not there before the 
injection of this liquid ? In order to ascertain what takes place in the 
lymphatic, vessels during absorption, we must begin by examining Um 
state of these vessels before the experiment. But this is what Hunter 
did not do, and it is this that renders his experiment of no value. It ii 
not very astonishing that he mistook the chyle for the milk, sinoa BQk 
has for a long time l>een mistaken for chyle. Flandrin, Profeeaor of 
the Veterinary School at Alfort, has several times repeated this experi* 
ment of Hunter ; but he took care before the injection of the milk to 
ascertain that the lymphatics contained no white fluid ; and he never 
found any in their cavity after the experiment. I have myself manj 
times performed this experiment, with the tame precaution, and I have 
uniformly obtained the same results as those of Flaodrin. 

It would occupy too much time to examine all the reasons that have 
been advanced for and against the absorption of the lymphatics ; I tball 
only relate some experiments I have made myself; but I ought first to 
observe, that, absorption undoubtedly takes place in parts such aa the 
eye, the brain, and the placenta in which the most minute dissection 
has been unable to discover any lymphatic vessel. 

First experiment, — Four ounces of the decoction of rhubarb waa 
given to a dog, in half an hour after he was killed, and it was found that 
more than half of the liquid had disappeared ; the urine evidently contain* 
ed rhubarb, but the lymph in the thoracic duct exhibited no trace of i|. 

Second experiment, — A dog swallowed several ounces of alcohol 
diluted with water ; at the end of a quarter of an hour, the blood of 



ON LIFE AND DEATH. 93 

accordingly. In this way,- in different circumstances, 
resolvents may be taken from the class of tlie debilitating 
or stimulating remedies. 



the animal had a very dbtinot odour of alcohol, but there was noUiing 
of the kind in the Ijmph. 

Flandrin made a Bimilar experiment on a horse, to whom he g^ye 
half a pound of assafetida mixed with an equal quantity of honey. 
Six hoar% after, the horse was killed* The odour of the assafetida waa 
yery perceptible in the blood of the yeins of the stomach, of the small 
intestines and the coeoum ; but it could not be perceived in . the 
Ijmph. 

mrd experiment, -^k dog was made to swallow six ounces of a 
flolution of Prussiate of Potash in water. In a quarter of an hour, the 
urine very evidently contained aome of the Prussiate ; but the lymph 
taken from the thoracic duct showed no appearance of it. 

Fdurtk experiment» — 1 gave to a dog, in whom I had tied the thoracic 
duct, two ounces of a decoction of nux yomica. The effects of absorp- 
tion were as rapid as if the duct had been open. After the death of the 
animal I satisfied myself, that the duct had been well tied, and that 
there was no other branch, as there sometimes ii, by which the lymph 
could get to the subclavian vein. 

I haye varied this experiment by putting the poisonous fluid, into the 
rectum, the sacs of the pleura and peritoreum. The results have been 
uniformly the same. 

Fifth experiment, ^-M, Delille and myself made an incision into the 
abdominal parietes of a dog, who had been fed very heartily some hourt 
before, so that the lacteals might be easily seen, and we then drew out 
a portion of the small intestine upon which we applied two ligatures 
three inches from each other. The lymphatics that went from this 
portion of intestine were full of chyle and yery distinct. They were 
all tied and cut. The blood vessels were also tied and cut, with the 
exception of an artery and a vein ; the portion of intestine also was 
cut off beyond the ligatures, and thus it had no communication wHh 
the rest of the animal except by the vein and artery which were left. 
These two vessels were dissected with the greatest care, and even 
stripped, of their cellular coat, lest there might be some lymphatics 
concealed in it ; we then injected into the cavity of this portion of 
intestine a decoction of nux TiMnica, and we retained it there by means 
of a new ligature. Tlui portion of intoftme, coyered with fine linen, 



84 PHYSIOLOGICAL RESEARCHES 

The whole of the theory of inflammation is connected 
with the above ideas. It is well known that the system 

wai restored to the abdomen ; tix miontet after, the effects of the poison 
were manifetted with their URual intensitjr. 

^Sixth experiment» — M. Delille and mjrfelf separated 4be thigh of a 
dog from hif bodjr, leaving only the crural arterj and yein, which kept 
«p the communication between the two parts* These two vessels were 
dissected with care, insulated to an extent of from two to three incheti 
end even stripped of their cellular coaf, for feer it might conceal sonM 
small lymphatic Yes«el. Two grains of a yery actif e poison (the upas) 
werç then inserted into the paw, and the effects were as «udden and ei 
intense as if the thigh bad not been separated from the body. 

As it might be objected, that notwithstanding all the preceutknif 
taken, the parietes of the artery or vein might still contain some 
lymphatic, we Tsried our experiment so as to leave no doubt on tbif 
point. The artery was-cut entirely off, the communication was reetteb« 
liched between the two end«, by means of a leaden tube introdnoed 
into their cavity, and fixed by proper ligatures. The same was done 
for the vein. Thus there was no longer any communication between 
the thigh and the rest of the body, except by the arterial blood wbioh 
came to the thigh, ami by the venous blood which returned to the 
trunk : the poison afterwards introduced into the paw- produced Hi 
e&cts in the ordinary time, that is in about four minutes. 

From these different experiments, it is right to conclude that the 
ibinute branches of the vein* possess the power of absorbiniif ; that 
they exert it on the surface of the mucous and serous membranes, end 
in the interior of the organs ; that the experiments that have been 
quoted in favour of the absorption of the lymphatics are inaccurate or 
incorrectly understood, end finally that there is no proof that these 
vessels aiMorb any thing but chyle. 

Is it now necessary to refer to the venOus branches this sensibility that 
has been attributed to the ultimate ramifications of the lymphatics ? But 
this sensibility, as we have already said, would be constantly in error's 
the absorbent vessel does not select one fluid in preference to anotheri 
all are indiscriminately absorbed, even the most irritating, those in fact 
whose action is sufficiently powerful to destroy the vascular parietea* 
Besides, the phenomenon then continues, when it is no longer possible 
to suppose the existence of this sensibility. After death even, the 
venous branches absorb still as they do during life, if they are placed in 
analogous circomstances ; and to do this it if evident, that an internal 



ON LIFE AND DEATH. 9S 

of the canals, which circulate the blood gives birth to a 
number of other small vessels* which admit only the 

eorrent mast be established, which resembles the course of the blood. 
I shall now relate an enperiment, which I made- on this subject, and 
which I selected from many others, because it appeared to me to be 
▼ery conclusite. 

I took the heart of a âog that had died the day before ; I injected 
into one of the coronary arteries some water of the temperature of 30 
degrees of the centigrade thermometer. This water returned easily by 
the coronary vein to the right auricle, whence it flowed into a 'vessel or 
dish. I poured half an ounce of slightly acid water into the pericar-' 
dium. At first the injected water exhibited no sign of acidity ; but in 
five or six minutes it presented unequivocal marks of it. 

Absorption then oan take place without the assistance of this sensf* 
bility, as well as of this insensible organic mobility, which is supposed 
to be in the ultimate vascular extremities, in the absorbing mouths, as 
they are calledv But do these mouths really exist ? Do the last capiN 
lary branches terminate abruptly with a hiige opening on the surface of 
the membranes or in the texture of the organs ? Can the absorbed 
fluids pass through their parietes as oxygen does in the lungs to arrive 
at the blood which it modifies ? We are unable to make experiments on 
these small ? essels, that are not cognizable by oar senses ; let us make 
them on the large ones, and if they permit fluids, in which they are 
immersed, to pass throue;b them, for a stronger reason we may suppose 
that it takes place in the capillaries, who»e parietes are so much more 
delicate and consequently more permeable. Now we have confirmed 
by experiments what we had suspected ; the first attempts were made 
on dead vessels. 

I took a portion of the external jugular vein of a dog ; I stripped it 
of the surrounding cellular texture ; I attached to each of its extremi- 
ttes a glass tube, by means of. which I esthblished a current of warm 
water through its interior; I then immersed the vein into a liquor 
slightly acid. • • 

It is seen by the arrangement of the apparatus that there could not 
be any communication between thé internal current of warm water 
and the external acid liquor. 

During the first minutes the liquid that I collected did not change its 
nature ^ but after five or six minutes the water became perceptibly 
acid ; absorption had taken place. 

The same experiment was repeated on veins taken from human 



96 PIITSIOLOGICAL RESEARCHES 

serous part of this fluid. Why do not the red globules 
pass into the serous vessels, though ihere exist a conti- 

■objects; the effect wai the tame; it was fbe^Mune alio with the 
arteries, bat a little slower from the greater thickness of their coats* 

It remained to be seen if in a living animal absorption thus took pkee 
through the parietes of a large yessel. I know that the textures that 
were permeable after death, are almost all so -during life, though the 
contrary is generally believed. If we inject into the pleura of a lifiag 
animal a certain quantity of ink, at the end of an hour, and often 
sooner, we shall find the pleura, the pericardium» the intercoalii 
muscles, and the surface of the heart itself, evidently of a black colour* 
It is true that the signs of this exudation are not always apparent* 
-Thus after death, the transudation of the gaU bladder is- rendered 
evident by the colouring of the neighbouring parts. During life, on 
the contrary, as fast as the colouring particles are deposited, thej arm 
absorbed by the serous membrane which covers the surrounding partt, 
and carried off* by the sanguineous current which runs through tbii 
membrane and the subjacent organs. 

From these considerations we must believe that absorption may taks 
place through the parietes of the vessel during life as after death. To 
be satisfied of this I made the following experiment ; 

I took a young dog of about six weeks old. At thu age the vatcnlnr 
parietes are delicate, and consequently more likely to render the exps* 
riment successful. I laid bare one of the jugular veins ; I insulated it 
perfectly in its whole length ; I stripped off carefully every thing j^hich 
covered it, and especially the cellular texture and some small veasels 
that ramified on it ; I placed it on a card, that it might not be in con- 
tact with the surrounding parts ; I then let fall, on its surface ^mA 
opposite the middle of the card, a thick aqueous solution of an alcoholic 
extract of nux vomica, a substance the action of which is very power- 
ful on dogs ; I took care that none of the poison could touch any IbiDg 
but the vein and the card, and that the oourie of blood was free in the 
interior of the vessel. Before tbe fourth minute, the effects that I 
expected appeared, at first feeble, but afterwards with so much power 
as to render inflation of the lungs necessary to prevent the death of the 
animal. I repeated this experiment on an adult animal ef a much 
larger sixe than the preceding one ; the same effects appeared bot 
slower, on account of the greater thickness of the parietes ; they begab 
to appear in fact after the tenth minute. 

After satisfying myself with this result refptetiag the veins, I tfaooght 



ON LIF£ AND DEATH. 97 

nuity of canal ? The cause by no means consists in the 
disproportion of the vessels to the globules as Boerhaave 

I would ascertain if the arteries exhibited ioialogotu properties. These 
vessels are in a less fayoarable conditioji ; their texture is less spongj 
than that of the veins and with ;ai} equal caliber, their parietes are much 
thicker. It was easy then to foresee^ that if the phenomenon of absorp- 
tion showed itself, it would appear .much slower than in the veins ; this 
was confirmed in an experiment on two ]a^e rabbits, in whom I dis- 
sected perfectly clean one' o/ the carotid arteries. It was more than a 
quarter of an hour before the solution of nux vomica passed through 
the parietes of the artery. As soon as I saw the symptoms of poisoning 
distinctly, I stopped moistening, tb^ vessel ; yet one of the rabbits died. 
In order then to convince myself that the poison had really passed 
through the arterial parietes^ and that it had not been absorbed by 
small veins which might have escaped my dissection, I carefully detach- 
ed the vessel that had been used jn the experiment ; I cut it open yi 
its whole extent, and I made those who assisted me) taste a little of the 
blood, that was still adhering to the internal surface ; they all perceived 
in it, and I did myself, the extreme bitterliess of the extract of the nux 
vomica. 

To these experiments may^ be objected- a fact that is observed, which 
is, that absorption does not take place the same under all circum- 
stances ; itiB activity is redoubled or diminished, according to the state 
of some other functions. Thus during a paroxysm of fever, a medicine, 
which would usually act irith great effect, often produces, when given 
in a double or treble dose, no perceptible effect. Now if absorption, 
was a purely mechanical phenomenon, would it undergo modifications 
in relation with those of the vital functions ? Without doubt it would ; 
for these modifications of the functions may introduce new physical 
circumstances favourable or injurious to the production of a mechanical 
phenomenon. Thus in the present case, the state of fever, by aecele"* 
rating the circulation distends with blood the arteries and the veins* 
The fluid that is to be absorbed must pass from the exterior to the 
interior of these vessels. Now it may be easily conceived, that the 
quantify of blood which they contain must have a great influence upon 
the production of the phenomenon by the greater or less degree of 
tension of their parietes. This is moreover completely confirmed by 
experiment. 

We can, without producing a very great disturbance in the functioBf^ 
increase at pleasure the quantity of fluid which paMea through the 

13 



--..•> 



98 PHYSIOLOGICAL RESEARCHES 

bas taught The breadth of the white vessels nright be 
double or triple that of the red vessels, and still the 

blood-vettelf, by carefully injectinjç into the Teini water the tempera- 
ture of which it near that of the blood. An artiâcial plethora it thus 
produced, foUowed by very curioo* phenomena, of which I shall have 
occasion hereafter to speak. One day while making; this experiment, 
the idea occurred to me of seeing what influence the plethora thus pr<^- 
duced would exert npon the phenomf'non of absorption. 

In consequence, after having injected into the veins of a dog^of 
middle size about a quart of water, I placed in the pleura a small ckwe 
of a substance, the effects of which were well known to me. These 
effects did not show themselves till many minutes after the period m 
which they usually appear. I soon made the same expertment OR 
another animal with the same result. 

In many other trials the effects showed themselves at the period in 
which- they ought to have appeared ; but they were evidently. weakiT 
and prolonged much beyond the ordinary time. 

Finally, in another experiment in which I had introduced ai nmoK 
Water as the animal could bear and live, the effects did not appear at 
all. I waited nearly half an hour for effects which commonly thow 
themselves in two or three minutes. Presuming then that the disten- 
sion of the vessels prevented the absorption, I endeavoured to satisiy 
myself of it, by seeing if after the distension had ceased^ absorptkNi 
would be any longer prevented. In consequence, I bled the aniin^ 
copiously from the jugular, and I saw, witk the greatest satisfaction, 
the effects appearing as the blood flowed out. 

It was proper to make the opposite experiment, that is to say to 
diminish the quantity of blood, in order to see if absorption would take 
place sooner. This took place in fact, as I thought it would ; aboot 
half a pound of blood was taken from an animal ; the effects, which 
did not usually appear till after the second minute, showed themselves 
in thirty seconds. 

Yet it might still be suspected, that it was less the distension of the 
blood-vessels than the change of the nature of the blood that opposed 
absorption. To remove this difficulty I made the following experiment; 
a dog was bled copiously ; the place of the blood which he had lost 
was supplied by water at the ti^mperature of 40 deg:rees of the centi- 
grade thermometer, and a certain quantity of a solution of nux Tomica 
was introduced into the pleura. The consequences of it were as 
prompt and as powerful, as if the nature of the blood had not been 



ON LIFE AND DEATH. 99 

globules of the latter colour would not pass into thçm, if 
there were not to exist a relation between the sum of the 

cbauged ; it was then to the distansion of the vessels that must be 
attributed the want or diminution of absorption. 

The consequences that may be deduced from the experiments I have 
jost related will acquire new force, if we connect with these facts a 
multitude of pathological ones, which are every day seen ; such as the 
cure of/ dropsies, engorgements and inflammations by bleeding; the 
evident want of action of medicines at the moment -of a violent fever, 
when the va$>cular system is powerfully distended ; the practice of 
certain physicians who purs;e and 'bleed their patients before administer- 
ing active medicinee to -them ; the employment of cinchona at the period 
of remission for the cur« of intermittent fevers ; general or partial oedema 
from organic disease of the heart or lungs, and the application of a liga- 
ture upon the extremities after a puncture or a bite of a venomous animal, 
to prevent the deleterioue: effectfi which are the consequence of it. 

On the whole, I think, it may be concluded from the preceding 
experiments that the capillary attraction of the small vessels is one of 
the principal causes of the absorption called venous. If the lymphatics 
do not appear to enjoy in the same manner the faculty of absorption, 
it probably arises not from the nature of the parietes, the physical 
properties of which are nearly the same as those of the veins, but from 
the want of a continuous current in their interior. 

In this note 1 have brought together the absorption of the gases aiid 
that of fluids. This resemblance holds only as it relates to the perme- 
ability of the textures by these two orders of bodies. As to the cause 
of the absorption of the two, it cannot be the same, since gases are 
not si^bjected to capillary attraction.* 

• J^ott by tilt Translator of J\fagendit*s •Addition*. — In the preceding 
note M. Magendie has not done justice to Mr. Hunter. ' Without enter- 
ing at all into the examination of the question, whether absorption is 
performed by the lymphatics or the veins, it is due to Mr. Hunter to 
contradict the assertion, that " he overthrew the ancient theory hjjive 
experiments only,^^ He was not a man who adopted his opinions 
loosely or on slight grounds, and in the present case he performed 
between twenty and thirty judicious and satisfactory experiments, in 
the presence of several physicians and surgeons. It is true that these 
were performed on five different animals only, but if the result were 
uniform, this number was as good as^ve thousand or any other one tha^ 
could be named. G. H. 

(See Hanteras Commentaries and Cruikshank on the Absorbents.) 



4823^ 



100 FHTSI0L06ICAL RESEARCHES 

sensibility of the vessels, and the nature of the globules. 
Neither will the chyme pass into the Choledochus, though 
the diameter of this canal be very much larger, than that 
of the attenuated molecules of the aliments. Now in the 
healthy state, the quantity of sensibility in the white 
vessels being inferior to that in the red ones, it is evident 
that the relation necessary to the admission of the colour^ 
ed globules cannot exist. But if any cause should exalt 
their powers, their sensibility will be on a par with that 
of the Jatter set of vessels, and the passage of the fluids 
till then refused, will take place with facility. 

Hence it happens, that those surfaces, which are the 
most exposed to such agents as exalt the sensibility, are 
also the most subject to local inflammation, as may be 
remarked in the conjunctiva and the lungs; at which 
time such is usually the increase of sensibility in the 
part, that of organic, which it was, it becomes aninial, 
and transmits to the brain the impressions, which are 
made upon it. 

Inflammation lasts as long as there subsists an excess 
of sensibility ; by degrees it diminishes, the red globules 
cease to pass into the serous vessels and resolution takes 
place. , 

From this it may be seen that the theory of inflamma- 
tion is only a natural consequence of the laws, which 
preside over the passage of the fluids into their respec- 
tive tubes ; hence also it may be easily conceived how 
unfounded are all hypotheses, which are borrowed from 
hydraulics, a science, which never can be really applied 
to the animal œconomy, because there is no analogy 
between a set of inert tubes, and a series of living ducts.* 

•Thoie theories do doubt are very incomplete (bat are borrowed 
from hjrdranlics, and probabljr will be so for a long time ; but it anset 
from this, that the science^on which it is founded, hydrodjnainici, k ttiU 



ON LIFE AND DEATH. 



101 



I should never have fiDÎshed were I to enumerate the 
consequences of this principle in the phenomena of the 
living man. The reader will easily enlarge the field of 
these consequences, the whole of them will form almost all 
the great data of physiolog^r, and the essential points of 
the theory of diseases. 

But no doubt it will be asked, why the organs of the 
internal life have received from nature, an inferior degree 
of sensibility only, and why they do not transmit to the 
brain the impressionsy which they receive, while all the 
acts of the animal life imply this transmission? the reason 
is simply this, that all the phenomena, which establish 
our connexions with surrounding objects ought to be, and 
are in fact under the influence of the will; while all those, 
which serve for the purpose of assimilation only, escape, 
and ought indeed to escape such influence. Now for a 
phenomenon to depend upon the will, it is evidently 
requisite that the individual be possessed of a conscious- 
ness of such phenomenon, to be withdrawn from the 
influence of the will, there should exist no such conscious- 
ness. 

bat irttle advanced. A great advance will anquestionablj be made in 
physiology, when we shall am? e at a knowledge of <he course of a flntd 
in a system of canals, which have the same physical conditions as the 
system of arterial and venous vessels. Biit it will be a long time before 
science will have arrived at that point. Is it necessary for this to make 
no use, in the explanation of the circulation, of the few facts which are 
known upon the coarse of the fluids P Is it necessary to enter entirely 
into the field of hypothesis, to sopposA in the small vetisels a sensibility 
and a contractility which evidently do not exist in the large ones ? I 
cannot believe it, and I think even that if this hypothesis should be 
true, and if there should be demonstrated for tlie capillary vessels, 
those properties which are attributed to them, and which would have 
an influence on the coarse of the blood, we should then know but one 
of the conditions of this very complicated problem, and this would not 
in any degree do away the necessity of knowing all the mechanical 
conditions. 



102 PHYSIOLOGICAL RESEARCHES 

V. Of the two kinds of contractility ^ the animal^ and 

the organic contractility. 

Contraction is the ordinary medium, by which the 
motion of the animal organs is effected; some parts, 
however, move by dilating themselves, as the iris, the 
corpora cavernosa, the teat and others ; so that the two . 
general faculties, from whence spontaneous motion is 
derived, are contractility and active extensibility ; the' 
latter of these should be carefully distinguished from 
passive extensibility^ of which in a short time we shall 
speak. The first is a property of life, the second a pro- 
perty of texture ; but as yet there exist too few data upon 
the nature and mode of the motion resulting from the 
former ; it is exemplified in too small a number of organs, 
for us to be enabled to pay much attention to it in these 
general considerations. — Accordingly we 4shall occupy 
ourselves only upon the subject of contractility; with 
respect to that of active extensibility, I refer to the 
writings of the physicians of Montpellier. 

Spontaneous motility, a faculty inherent in living 
bodies, as well as sensibility, possesses two great modifi- 
cations, which differ very much from each other, accord- 
ingly as it is examined'*in the phenomena of one or the 
other life. There is an animal contractility, and there is 
an organic contractility. 

The one being essentially subject to the influence of 
the will, has its principle in the brain, receives from the 
brain the ijc^adiations, which put it in action, and ceases 
to exist when the organs, in which it is observed, commu- 
nicate no longer with the brain ; it participates besides at 
all times with the state ef the braio, has exclusively its 
seat in the voluntary muscles,, and presides over locomo* 



ON LIFE AND DEATH. 103 

tloD, the voice^ the general movements of the head, the 
thorax and abdomen. The other, which is not depend- 
ent on a common centre, has its principle in the moving 
organ itself, is a stranger to the influence of volition, and 
gives rise to the phenomena of digestion, circulation, 
secretion, absorption, and nutrition. 

The two are quite distinct in all cases of violent death ; 
such death annihilates at once the animal contractility, 
and allows, for a longer or shorter time, the organic con- 
tractility to bé exercised; they are essentially distinct 
also in all cases of asphyxia; in these, the first is entirely 
suspended, the second remains in activity ; lastly they 
are distinct both in artificial pal^y and in that which is 
brought on by disease. In these, the voluntary motions 
cease ; the organic motions are unaltered. 

Both the one and the other kind of contractility are 
connected with their corresponding kinds of sensibility. 
They are a consequence of them. The sensation of 
external objects puts in action the animal contractility ; 
before the organic contractility of the heart can be exer- 
cised, its organic sensibility must be excited by the influx 
of blood. 

Nevertheless, the concatenation of these two kinds of 
faculties is not always the same. The animal sensibility 
may be exercised, and not be necessarily followed by the 
exercise of its analogous contractility. There is a gene- 
ral relation between sensation and locomotion^ but this 
relation is not direct and actual. On the contrary, the 
organic contractility can never be separated from the sen- 
sibility of the same species ; the re-action of the excret- 
ing tubes is immediately connected with the action, which 
the secreted fluids exercise upon them : the contraction 
of the heart must necessarily succeed the influx of the 
blood into it. But authors have by no means separated 



K 



104 PHYSIOLOGICAL RESEARCHES 

these two things, either io their considerations or their 
language. Irritability denotes at the same time the seqsa- 
tion excited in the organ from the contact of bodies, and 
the contraction of the organ in reacting upon its excitants. 

The reason of this difference in the relation of the 
two sensibilities and contractilities to each other is very 
simple. In the organic life, there is nothing intermediate 
in the exercise of these two faculties. The same organ it 
the term, in which the sensation ends, and the principle 
from whence the contraction begins. In the animal life, 
on the contrary, there exists between these two acts two 
intermediate functions, those of the brain namely, and 
the nerves, and these by not being brought into action 
may interrupt the relation in question. 

To the same cause must we refer the following observn- 
tion. In the organic life there always exists a rigorous 
proportion between the sensation, and the contractioiL 
In the animal life the one may be exalted or lowered, 
and the other not affected by such change. 

VI. Subdivision of the Organic contractility into ttbo 

Varieties/^ 

The animal contractility is always the same in what- 
ever part of the body it is situated. But there exist in the 
organic contractility two essential modifications, which 
would seem to indicate a difference in their nature, though 

*Even in reasoning according to the hypothesis of Bichat, and 
admitting the existence of this organic sensibility, it would always be 
inaccurate to say, that the contraction is uniformly in proportion to the 
sensation. How is it to be known in fact ? Since this sensibility is not 
transmitted to a common centre, it might very well be excited without 
our being informed of it by any apparent effect. Sometimes also a 
very evident xsoQtraction would correspond to the slightest excite* 
nent. 



ON LIFE AND DEATH. 105 

there be only diversity in outward appearances. This 
difference is sometimes visible, at other times though 
really existing, it cannot be seen by inspection. 

The sensible organic contractility may be observed in 
the heart, in the stomach, intestines, bladder,* and other 

* The contractility in the diferent organi in which we can observe 
it does not exhibit characters so striking as those which Bichat here 
aas^ns to it, and the motions which he ranks in the same class have 
the greatest differences among them. To be convinced how little 
jastice there is in this diviMon, it will be sufficient to trace the progress 
of the food, along its whole course, to the interior of the digestive 
canal. The first act which is presented to our observation is entirely 
voluntary ; this is mastication ; the act which follows it is not so com- 
pletely so. Deglutition in fact can sometimes take place against the 
will, if a body of a proper consistence is at the entrance of the pharynx. 
We have but an imperfect control over the muscles of the uvula and 
the velum palati, if we wish to move these parts separately ; we have 
perhaps less power still over the contraction of the muscles of the 
pharynx, though they do not appear to differ from the locomotive 
muscles, either in their symmetry, or in the arrangement and colour of 
their fibres, or in the nerves which they receive ; nor finally do they 
differ in the sudden, instantaneous contraction, wholly different from 
the slow contraction, the vermicular motion of the stomach and intes- 
tines. 

After having passed the pharynx» the alimentary mass enters the 
cesopbagus. The motions are there still under the influence of the 
nerves ; but they are not at all under the influence of the will. The 
muscular layer which produces them has not the appearance, the red 
colour of the voluntary muscles ; but it still preserves something of 
the sudden motion of their contraction. Hence we see, that the 
motions of the œsophagus cannot be ranked either among the motions 
of organic life, since they cease by the division of the nervei*, or among 
those of animal life, as they are not under the influence of the will. It 
is remarkable also that Bichat, who, in this and the following paragraph, 
announces the characters of the different kinds of contractility, does 
not speak of the œsophagus, whilst he offers as an example the motions 
of the bladder, the heart, the stomach and the intestines. 

When Bichat wrote this work, hardly any thing of the motions of 
the œsophagus was known, except from the writings of Haller, who 
made but four experiments on the subject. I wished to observe them 

14 



lOG PHYSIOLOGICAL RESEARCUES 

organs. It is exercised upon very considerable quantities 
of the animal fluids. 

iDj»eIf, and I have discovered many facts which I think interesting ; I 
•ball relate them here as 1 described them in a memoir read to the 
Inatitnte in 1813. Before attempting to aacertain what part the oeso- 
phagus took in the passage of the food, it was proper to ascertain iti 
state when it was supposed to be at rest. In the first experiments, I 
noticed an important phenomenon, and which hitherto had escaped the 
obserration of physiologists, yiz, that the lower third of the <9sopha(M 
has constantly an alternate motion of contraction and re]a:tatioD, which 
appears to t>e independent of all foreign irritation. This motion appears 
to be confined to the portion of the tube which is surrounded by the 
plexus of nerres of the eis^hth pair, that is to say, to about its lower third ; 
there is no trace of it in the neck nor in the superior part of the thorax.' 
The contraction appears like a peristaltic motion, it begins at the junc- 
tion of the superior two thirds with the inferior third, and is contînotâ 
to the insertion of this tube in the stomach. When the contraction Is 
once produced, it continues for an uncertain time ; usually it is less 
than half an hour. The œsophagus contracted in this way in its lower 
third is hard like a cord powerfully stretched. Some persons whom I 
have made feel of it in this state have compared it to a rod. When 
the contraction has lasted the time 1 have just mentioned, the relaxft» 
tion takes place suddenly and simultaneously in each of the contracted 
fibres ; m some cases, however, the relaxation seems to take place from 
the superior fibres towards the inferior ones. The œsophagus examined 
daring the state of relaxation exhibits a remarkable flaccidity, which 
contrasts wonderfully with the state of contraction. 

This alternate motion is dependent on the nerves of the eighth pair. 
When these nerves are cut in an animal, this motion entirely ceases ; 
the œsophagus contracts no more, but it is not in a state of relaxation ; 
its fibres without the control of nervous hifluence shorten; it is thb 
which produces, so far as the touch is concerned, on intermediate state 
between contraction and relaxation. 

When the stomach Is empty or half fuU of food, the contraction of 
the œsophagus recurs at much longer intervals ; but if the stomach be 
powerfully distended by any cause, the contraction of the œsophagus 
is nsnUly very powerful, and continues for a much longer time. I have 
seen it, in cases of this kind, continue more than ten minutes ; nnde^ 
the same circumstances, that is to say, when the stomach it excesnvelj 
lull, the relaxation is always much shorter. 

If during the Hbo of contraction, we wished, b^ mechanical prearart 



r 



ON LIFE AND DEATH. 107 

The insensible organic contractility is that, by virtue 
of which the excreting tubes re-act upon their respective 

made on the stomach^ to make a part of the aliments which it contained 
pasi into the œsophagus, it would be necessary, in order to accomplish 
it, to employ a very considerable force ; and often even wt should not 
succeed. It seems that pressure increases the inteoaity of the contrac- 
tion, and prolongs its duration. If, on the contrary, the stomach is 
pressed daring relaxation, it is very easy to make the substances it 
contaios pass into the cavity of the œsophagus. If it be a liquid, the 
slightest pressure, sometimes even its own weight, or the tendency 
which the stomach itself has to contract, will bring about this result. 
When the stomach is laid bare and distended above measure, fluid does 
not usually enter into the œsophagus, because, as we have said, the dis- 
tension of the stomach is a cause which prolongs the contraction of the 
œsophagus. 

The passage of a fluid in the œsophagus is usually followed by its 
entrance into the stomaoh. Sometimes however the fluid is thrown out. 
When.it goes into the stomach, the œsophagus contracts nearly the 
same as in deglutition, sometimes almost immediately after it has entered 
it ; at otber times the œsophagus allows itself to be considerably dis- 
tended before it pushes it into'the stomach. 

It was at the moment of deglutition that Haller observed the motion» 
of the œsophagus, and the description which he has given of them is 
very accurate for the two superior thirds of the canal ; but the action 
of the inferior third is essentially difierent ; and this distinction seems 
to have escaped him. Haller says that the relaxation of each circular 
fibre. immediately follows the contraction ; and this is true of the por- 
tion of the canal situated in the neck and in the superior part of the 
thorax \ but R is not accurate for the inferior portion, in which we see 
that the oontraction of all the circular fibres is continued long after 
the entranoe of solids or fluids into the stomach. At this moment the 
mucous membrane of the cardiac extremity of the œsophagus, pushed 
by the contraction of the ciieolar fibres, forma m very considerable 
projection into the cavity of tlte stomach. The contcaotion usually 
coincides with the period of inspiration, when the stomach is mora 
strongly compressed ; the relaxation takes place most often at the time 
of expiration. When the aliments ha?a once entered the stomach, it 
is this contraotipii of the inferior part of the œsophagus which opposes 
their retofik The resistance that is offered at the other orifice is not 
of the saoNI species. ||i living animals, whether the stOBMch be empty 
or fall» the pyloros is anîfonnly that by the contraction of its fibrous 



108 PHYSIOLOGICAL RESEARCHES 

fluids, the secreting organs upon the blood, which flows 
into them, the parts where nutrition is performed upon 

ring and the contraction of its circular fibres. There is frequentljr seen 
in the stomach another contraction, at one or two inches dittance^ 
which appears to be designed to prerent the aliment!! from arriring^ 
at the pjloms. We perceive also irregular contractions, beginning at 
the duoderum, and extending to the pyloric portion of the stomach, 
the effect of which is to posh back the aliments towards the splenic 
part. 

The aliments remain in the stomach long enough to undergo no 
other modifications than thore which result from their Inixture with the 
per»piratorj and mucous fluids, which are constantly found in it and 
renewed there. During this time the stomach remains uniformlj die* 
tended ; but afterwards the pyloric portion contracts in its whole 
extent, especially in the part nearest the splenic portion, towards which 
the aliments are carried. Then there is found, in the pyloric portion, 
only the chyle mixed with some unchanged aliments. When there if 
accumulated in this part a quantity of it, which is never very considéra» 
ble, there is seen, after a moment of rest, a contraction at the extremity 
. of the duodenum ; the pylorus and the pyloric portion soon take part 
in this motion, and the chyle is forced towards the splenic portion ; bnt 
afterwards the motion is in an inverse direction. The pyloric portioa, 
which allowed itself to be distended, contracts from left to right, and 
directs the chyle towards the duodenum, which soon passes the pylorm 
and enters the intestine. The same phenomenon is repeated a certain 
number of times, then it ceases, and commences again after sometime* 
This motion, when the stomach contains much food, is limited to that 
part of the organ nearest the pylorus ; but as it becomes emptj, tho 
motion extends, and appears even in the splenic portion when the 
stomach is almost entirely evacuated. In general, it becomes more 
evident at the end of chylification. 

The motion which produces the progression of the chyle in the small 
intestines is very analogous to that of the pylorus ; it is irregular, made 
at variable intervals, it is sometimes in one direction and sometimes in 
another, and sometimes appears in many parts at once ; it is always 
more or less slow, it produces changes of relations in the intestinal 
circumvolutions, and it is entirely beyond the influence of the will. 

We should form a very false idea of the motions of the small intes- 
tines during digestion, if we judged of them by those which these 
intestines exhibit in an animal recently killed. In this case, it it not 
the annular fibres only that enter into action, so as to exhibit, (gr their 



ON LIFE AND DEATH; 109 

the nutritive juices, and the lymphatics upon the sub- 
stances which excite their open extremities, upon all these 

luccessife contractions, a vermicular motion. The longitudinal fibres 
act also in a verj conspicuous manner, and produce a rolling of the 
intestinal circumvolutions, which change their relations at eyerj instant. 
These motions are never more evident than when the whole mass of 
intestines is removed from a living animal. 

The motions of the large intestines have nearlj the same character! 
as those of the small intestines, like the^e last, thej are not always in 
the same direction, but push the substances which are contained in 
their cavity, sometimes towards the ileum and sometimes towards the 
anus. But by means of this motion, these substances which have 
already the character of /ecet , can never re-enter the small intestines. 
The caufie that prevents their return is different from that which pre- 
vents the return into the stomach of the substances contained in the 
duodenum. The obstacle in this case, we have said, is produced by 
the contraction of the contractile rings, which are found at the 
extremity of the two cavities ; in the other, it is produced by a cause 
purely mechanical, by the arrangement of the ileo cecal valve. Hence 
it follows, that if the mode of contraction of the different parts of the 
intestinal canal be perverted by any cause, it might happen that their 
contraction towards the pylorus would not take place when the duode« 
num was affected with its anti-peristaltic motion, and then the sub* 
stances contained iu it, pushed by the contraction of the annular fibres, 
would re-enter the stomach. At the coecum, on the contrary, as the 
obstacle is purely mechanical, so long; as the ileo-coecal valve is not 
broken, it will present an insurmountable obstacle to the return of the 
fteet into the small intestines. 

The motions of the lurge intestines, sufficient to carry the feces into 
the rectum, would not, in a state of health, be powerful enough to 
expel them entirely, by overcoming the remittance which the sphincter 
constantly presents; in expelling the feces, the contraction of the intes- 
tine is assisted by the pressure which arises from the lowering of the 
diaphragm, and by the contraction of the abdominal muscles. 

We have just pointed out the motions which carry the alimentary 
mass along the intestines. We may see that they have but little 
resemblance among them. The only character that is common to 
them is that of not being under the influence of the will. Yet there 
is an exception to this in some individuals who possess the faculty of 
ruminating. (The will is seen exerting itself on the production of other 
semihU 9rgmnc motwns» Bayle could atop at will the pulsation of his 



110 PHYSIOLOGICAL RESEARCHES 

occasions, wherever the fluids are disseminated in small 
quantities, or are very much divided, this second species 
of contractility is brought into exercise. A tolerably 

heart.) If we txamioe the motioni of the digestive tube when it it 
free of alimenti, we see their differeoce in a manner not Icpb striking. 
The œsophagtts exhibits those alternate motions that we have described ; 
a wery powerful contraction of its inferior third» and then suddenly the 
most complete relaxation. In the stomach we see only some ondula* 
tiens, that go irreeularlj from one orifice to another. In the intestines, 
these motions exhibit nearly the same regularity, bat the groove formed 
by the contraction of the annular fibres is deeper, and the undulatofj 
motion is not so slow. If a stimulating medicine is introduced into the 
stomach, these contractions become more evident^ and the motiona 
more rapid ; but they always preserve the same character. The con« 
traction takes place progressively, and never in the sudden manner of 
a muscle of locomotion. Of all the substances which can be used to 
ascertain these motions, there is no one whose action is more efficacioni 
than veratrine, a new vegetable alkali extracted from the veratrum 
tabadilla. If the external parietet of the digestive tube be excited by 
any stimulus, by touching it with the finger, by a puncture, or by the 
galvanic fioîd, there is in the oesophagus a sudden contraction of the 
longitudinal and circular fibres, which narrows the organ and shortem 
it at the same time ; the relaxation takes place instantaneously and in 
as striking a manner. In the stomach, no motion is l^erceived in the 
direction of its length ; we see only an annular contraction, which u 
developed slowly at the excited point, and which is usually not trans- 
mitted to the neighbouring parts. In the intestines, the e^icitement 
produces a very decided contraction, and very often in the neighbour- 
ing parts a kind of peristaltic motion ; but this motion is always slow and 
does not at all resemble the sudden contraction of the œsophagus. 

The difference between the motions of the œsophagus and those of 
the other parts of the intestinal canal is very remarkable in birds. la 
them the œsophagus appears to be entirely membranous ; and yet it con- 
tracts like a muscle of locomotion ; whilst the stomach, which has red 
muscles very similar to the locomotive muscles, has slow, gradual ver- 
micular motions, Hke all the canal which is below it. 

There exists finally between the motions of the intestinal canal a 
dififerenoe relath^e to the manner in which they terminate. Those of 
the intestines, but little sensible during life, acquire at the moment of 
death a very great intensity ; whilst those of the œsophagus, before so 
distinct, cease immediately, an^ in the most complete manner. 



ON LIFE AND DEATH. HI 

precise idea may be given of both, by comparing the one 
with attraction, a power which is exercised upon the 
great aggregate of matter, and the other with the chemi- 
cal affinities, the phenomena of which take place in the 
molecules of different substances. For the purpose of 
explaining this difference, Barthez has compared the one 
to the second hand of a watch, which traverses the cir- 
cumference in a very apparent manner, and the other to 
the hour hand, which moves also, but whose motion is 
not distinguishable. 

The sensible organic contractility nearly answers to the 
irritability of authors; the insensible organic contractility 
to what is called tonicity. But these words seem to sup- 
pose in the propertie9> which they indicate a difference of 
nature, while this difference exists only in appearance. I 
therefore prefer employing for both a common term. It 
designs their general character, that of appertaining to the 
interior life, and their independence with regard to the 
will. To this term I join an adjective expressive of 
the particular attribute of each. 

In fact we should possess a very inaccurate idea of 
these two modes of action, were we to consider them as 
proceeding from different principles. The one is but the 
extreme of the other ; they are both connected by insen- 
sible gradations. Between the obscure but real contrac- 
tility, which is necessary to the nutrition of the nails, 
and the hair, &c. and that which we see in the motions 
of the stomach, and intestines, there exist innumerable 
shades of this property, which serve as transitions be- 
twixt its perceptible degrees ; such are the motions of the 
dartos,* of the arteries, and of certain parts of the cutane- 
ous organs. 

* It is not the dartos that contracts in the motions of the scrotum, it 
k the skin itself that produces that vermicular motion that is observed 



112 PHTSIOLOOICâL RESEARCHES 

The cireulatioD will give us a very good idea of this 
graduated enchainment of the two kinds of orgaoic con- 
tractility. The sensible organic contractility presides 
over this function in the heart and large vessels^t by 

in this part. Thii motion can be produced bj stimnli of yctj different 
kinds ; by the impression of cold, by pinching the skin or bj fear. I 
have seen these motions so great in a man on whom I was about to 
operate for hydrocele, that I was obliged to wait for a long tote for 
fear of woonding the testicle, which, by those motions, ascended and 
descended fprecipitately. 

t It in%ht be thought from this espretsion, that Bichat snppoeed that 
the great arteries inflaenced the course of the blood by an acthro eon- 
traction analogous to the muscular contraction ; but this was not bis 
opinion. He only wished to say, that the blood continued to oaoTe in 
the great arteries solely by the influence of the heart. This contraction 
of the great arterial trunks has been heretofore maintained by many 
anatomists, and is even at present by some. There are at the prêtent 
day three principal theories relative to the circulation. 

In the first, it is contended that all the parts of the arterial ayattB 
are irrKable, and that they contract like the muscular texture ; maflj 
even addK^at they can dilate spontaneously, as takes place every 
instant in thè^-heast. According to this supposition, the arteries alone 
would be able to continue the course of the blood. 

In the second opinion, which is that of Harvey, and which ia stiD 
adopted, more particularly by the English physiologists, it is affirmed 
on the contrary, that the arteries are not contractile in any point ; that 
if they do contract in certain cases, it is in virtue of that property 
common to all the solids, by which they return upon themselres, when 
the cause that has distended them ceases to act. The partisans of this 
opinion conclude that the arteries have not and cannot have any influ- 
ence upon the motion of the blood which runs through them, and that 
the heart is the principal, and as it were, the sole agent of the circula- 
tion. 

Finally the third opinion, that which now prevails roost generally in 
France, consists in a union of the two preceding ones ; the trunks and 
principal arterial branches are considered as incapable of acting upon 
the blood ; but thi^ property is attributed to the small arteries, and it is 
thought to be very great in the last divisions of these vessels. Thus, 
in this mixed opinion^ the blood ii carried by the sole inflaenoe of the 



ON UrS AVD DEATH. 113 

degrees it become less apparent, in proportion as the 
diameter of the vascular system decreases ; and lastly, it 

heart in all the arteries of a considerable size ; it is moTed in part by 
the influence of the heart and in part by that of the parietei in the 
smaller arteries, and finally it is moved by the sole action of the parietes 
in the last arterial divisiens. This action of the small vettels is also 
described as the principal cause of the course of the blood in the veins. 

In a question of this nature pur . opinion should be determined by 
experiments alone. This presents many points for elucidation. 

The first and the easiest to be decided is to ascertain if the arteries 
are or are not irritable. The problem was in some measnre resolved in 
relation to the great arteries by the experiments of Haller and his dis- 
ciples, by Bichat himself, and by those which M. Nysten hat made 
upon man. For the purpose of being more perfectly convinced, I have 
sought, by fill the known means, to develop the irritability of the 
arterial parietes ; I have successively subjected them to the action of 
pricking instruments, of caustics and of galvanism, and I have never 
perceived any thing which resembled a phenomenon of irritability ; and 
as those who maintain the irritability of the arteries pretend that if we 
do^not perceive the contractions, it is because the experiments are made 
on too small animals, in whom the effects are but slightly apparent in 
consequence of the small diameter of these canals, I have repeated the 
experiment on large animals, on horses and ^sses, and I have never 
observed any other motions than the communicated motions. 

As the great arteries show no contraction, we ought to believe that 
the small ones would not ; but as among the physiologists who reject 
the irritability of the arterial trunks, some like Haller, do not rpeak of 
the branches, others accord to them contractility, it becomes necessary 
to-test this question by experiment; now these small vessels, like the 
larger ones, remain perfectly immoveable under the action of the scal- 
pel, caustics and a stream of galvanic fluid. 

Irritability does not exist then in the large or the small arteries. 
Respecting; the last arterial division?, as the vessels which form them 
are so small that they cannot come under the cognizance of the senses, 
at least in a state of health,- no one can affirm of deny that they are 
irritable. Yet from analogy we ought to conclude, that they have no 
sensible motion. In cold-blooded animals, in fact, it is easy to see the 
blood circulating in these vessels, and even passing into the veins ; now 
the vessels themselves appear to be completely immoveable. 

As the arteries cannot act upon the blood by contracting in the 
15 



114 PHYSIOLOGICAL RESEARCHES 

is insensible in the capillary tubes, where tonicity only 
is observed. 

manner of musclef, mutt we conclade that tbej have no action upon 
this flaid, and that they are in relation to it nearly like inflexible canala ? 
I am very far from thinking to. If in fact the arteries had no inflaence 
npon the blood, this fluid, moved by the sole Impulse of the heart, 
would, from its incoroprestfibility, be alternately in motion and at reat« 
This is indeed what Bichat thought, and what he has ad?anced in his 
other works ; it is what has been since maintained in a more formal 
manner by Dr. Johnson of London. It is however very ehsy to proye 
that it is not in this way that the blood is moved in these yeaeelf*. 
Open a large artery in a living animal, and the blood will escape in a 
continuons jet, but by jerks ; open a small artery, and the blood will 
flow out in a continuous and uniform jet. The same phenomena take 
place in man if the arteries are opened, either by accident or in sargi- 
cal operation». The heart being unable to produce a continuous flow» 
since its action is intermittent, it iuu»t be then that the arteries act upon 
the blood ; this action can only be the disposition which they haTe to 
contract, and even to obliterate their cavity entirely. Bichat thoagbt 
that this tendency to narrowing was not sufficient in the arteries to expel 
the blood contained in their cavity. He maintains that the vessel does 
not contract upon itself only when the blood has ceased to distend it 
If it were so, the arteries would be equivalent to inflexible canals, aod 
the course of the arterial blood would not be continuous ; but we can 
easily demonstrate that the force with which the arteries contract ia 
more than f*ufficient to drive out the blood that they contain. 

When two ligatures are applied at the same time and at lOBie 
centimetres distant upon two points of an artery which furnishes no 
branches, we have a portion of artery in which the blood is subjected 
only to the influence of the parietes^ If we make in this portion of the 
vessel a small opening, almost all the blood that it contains is immedi« 
ately thrown out, and the artery is much contracted- This experiment 
has been known for a long time, and uniformly succeeds. The followiiq; 
is one of my own, and places, it seems to me, the phenomenon in a very 
clear light. 1 laid bare the crural artery and vein of a dog to a certain 
extent ; I passed under these vessels, near the trunk, a string, which I 
afterwards drew tightly at the posterior part of the thigh, so that all the 
arterial blood should come to the limb by the crural artery, and all the 
venous blood return to the trunk by the crural vein ; I then applied a 



J. 



ON LIFE AND DEATH. 115 

Should we consider irritability as a property inherent 
exclusively in the muscles, as being one of the characters 

li^ture upon the artery, and this yeatel was very loon completely empty 
in the part below the ligature. 

It is then Batisfactorily proved that the force with which the arteriet^ 
contract upon themselves is sufficient to espel the blood they contain. 
But what is the nature of this contraction ? We have proved that it 
cannot be attributed to irritability. Every thing leads to the belief 
that it should be referred to the very great elasticity which the ai^erial 
parietes enjoy, an elasticity that is brought into action, when the heart 
forces a certain quantity of blood into the cavity of these vessels. This 
property of the arteries being known, it is easy to conceive how the 
principal agent of the arterial motion, being alternate, the course of 
fluid is yet continuous. The elasticity of the arterial parietes is similar 
to that of the reservoir of air in certain pumps with an alternate 
action, and which notwithstanding throw out the fluid in a continuoui 
manner. 

It is not enough to Icnow the kind of influence which the contraction 
of the arteries has on the motion of the arterial blood ; it is necessary 
to know if this contraction does not influence in a sensible manner the 
course of the blood in the veins. This is elucidated by the following 
experiment. Lay bare, as in the preceding experiment, the crural 
artery and vein of a dog ; tie the limb strongly, taking care not to 
include these vessels ; afterwards tie the crural vein, and make a small 
opening in it below the ligature, of one or two lines in length ; the 
blood flows out in a continuous jet. If the artefy be compressed, so at 
to intercept the course of blood in it, the jet still continues a short 
time ; but it is seen sensibly to diminish, as the artery is becoming 
empty. It at length ceases entirely when the artery is completely 
emptied ; and though the vein remains distended with blood along its 
whole extent, it does not flow out at the small wound. If the com- 
pression be taken off of the artery, the blood enters it with force, and 
almost at the same instant it begins again to flow from the opening in 
the vein, and the jet is reestablished as before. If we check the course 
of the blood in the artery, there is but a feeble jet from the vein ; it is 
the same if the passage of this fluid is alternately intercepted and per- 
mitted. 

I make the same phenomenon evident in another way ; I introduce 
into the crural artery thé extremity of a syringe filled with water at 
the temperature of 30 degrees of the centigrade thermometer; 1 push 






116 PHYSIOLOGICAL RESEARCHES 

by which they are distinguished from other organs, and 
should we call this property by a name expressive of its 
peculiar seat in the muscle, we should conceive it, if I 
mistake not, in a very diflferent way from that in which 
it naturally exists. 

It is true, that in this respect the muscles occupy the 
first rank in the scale of the animal solids ; they possess 
the maximum of the organic contractility ; but «very 
living organ acts, as they do, though in a manner less 
apparent upon the excitant when artificially applied, or 
on the fiuid, which in the natural way is carried to it for 
the purpose of supplying the matter of secretion, nutri- 
tion, exhalation, or absorption. 

Nothing in consequence is more uncertain than the 
rule, which is commonly adopted for pronouncing upon 
the muscularity of any doubtful part ; for the rule con- 
sists in ascertaining whether such part does or does not 
contract under the action of stimuli. 

It is thus, that a muscular tunic is admitted in the arte- 
ries, although their organization entirely difiers from that 
of the muscles ; it is thus, that the womb is pronouncecL 
to be fleshy, however foreign to such structure; it is thus, 
that a muscular texture is admitted in the dartos, in the 
iris, and other parts, although no such structure be observ- 
able there. 

the piston tlowljr, and soon the blood goes out bj the opening in the 
vein, at first alone and afterwards mixed with water, and it forms a jet 
the more considerable in proportion to the force with which the piston 
is pushed. 

To prove, as we have done, that the heart maintains an evident influ- 
ence on the course of the blood in the capillary vessels, is not to 
advance that these vessels have no action on the motion of this fluid. 
Manj physiological phenomena, on the contrary, prove that the capilla- 
ries can aid with more or less facility the passage of the blood, and 
consequently sensibly influence its course. 



ON LIFE AND DEATH. 117 

The faculty of contracting under the action of irritating 
substances like that of the sensibility, is unequally dis- 
tributed among the organs ; they enjoy it in different 
degrees. We do not properly conceive it, if we suppose 
that it belongs exclusively to some of them. It does not, 
as some have imagined, possess its peculiar seat in the 
muscukr fibre. Life is the sole condition necessary to 
all the fibres for enjoying it ; their peculiar texture influ- 
ences the sum only, which they receive of it ; it appears 
that to «ueh an organic texture, is attributed, if I may 
so express myself, such a dose of contractility ; to such 
another texture, such another dose, and so on ; so that to 
employ the expressions, which I have used in treating on 
the subject of sensibility (however improper they may 
be, yet capable alone of rendering my ideas) the differ- 
ences in the organic contractility of our different parts, 
consist in the quantity only, and not in the nature of this 
property : indeed it is with respect to quantity only that 
this property varies, accordingly as it is considered in 
the muscles, the ligaments, the nerves, or the bones. 

If a special mode of contraction ought to be designed 
for the muscles by a particular expression, such expres- 
sion could be only derived from the property which they 
have of contracting from the influence of the will; but 
this property is foreign to their texture, and comes to 
them from the brain only ; for as soon as they cease to 
communicate with this organ directly by means of the^ 
nerves, they cease also to be the agents of voluntary motion. 

These considerations lead us to examine the limits 
which are placed between the one and the other kind of 
contractility. We have seen that those which distinguish 
the two modes of sensibility, appear to be derived only 
from the greater or less proportion of this power; that in 
a certain proportion sensibility is of the animal kind, in a 



118 PHYSIOLOGICAL RESEARCHES 

certain inferior proportion, of the organic kind, and that 
frequently from an augmentation, or diminution of inten- 
sity the two sensibilities reciprocally borrow their respec- 
tive characters. We have seen a phenomenon almost 
analogous to this in the two subdivisions of the organic 
contractility. 

But this is not the case with regard to the two great 
divisions of contractility considered in general. The 
organic can never be transformed into the animal contrac- 
tility. Whatever be its increase of energy, it constantly 
remains the same in its nature. The stomach, the intes- 
tines frequently assume a susceptibility of contractioOy 
which makes them rise up and produces in them* the 

* Under no circumstance does the stomach rite ap, as Bichat calls it. 
We have, in a preceding note, explained the ordinary motionR of thn 
Tisons, in a stat^ of vacuity, during digestion and under the inflaeDce 
of an internal or external stimulus. None of these motions are lofi- 
cient to produce that sudden and energetic expulsion which charac- 
terizes vomiting. The opinion that the stomach rises up in votnitiof 
originated in a time of ignon^nce, and we ought not to be astonîëhed 
that it should find advocates even in our day. This has not however 
been uniformly adopted ; Bayle and P. Chirac opposed it by experi* 
ments ; Senac, Van Swieten and Duverney declared themselves against 
it ; but Haller, by adopting it, suddenly changed the views and removed 
the uncertainty of a great number of physiologists, who, not taking the 
labour of making experiments for themselves, loved to repose on the 
faith of a celebrated name. In physiology the opinions of Haller are 
certainly entitled to very great weight ; this is because this wise observer, 
before announcing them as a general proposition, was accustomed to 
repeat many times the experiments on which he founded them ; but in 
this case he did not sufficiently question the use of the stomach in 
vomiting. 

He has made four experiments only, less for the purpose of satisfying 
himself that the phenomenon existed, than to see it such as he sup- 
posed it. It is very difficult, even for the best mind, to divert itself in 
observing, of the ideas previously received without examination. It 
may then be believed, that Haller in this way saw but superficially. 
These considerations determined me some years since, to satisfy myself 



ON LIFE AND DEATH. 119 

most violent motions by the most simple stimuli, but these 
movements preserve at all times their peculiar type, their 

of what takei place in ▼omitinff, and of the part which the stomach 
performs in it. I shall relate brieflj the experiments which 1 tried on 
the subject; The first was made on a dog of middling tize, whom I had 
made to swallow six grains of emetic. When this medicine had excited 
nansea» I cut through the' linea alba opposite the stomach, and intro- 
duced mj finger into the abdomen. At each nausea, I felt it Terj 
powerfnlljr compressed above by the liver, which the diaphragm pushed 
down, and below bj the intestines, which were compressed bj the 
abdominal muscles. The stomach also appeared to me to be com« 
pressed ; but instead of feeling it contract, it appeared to me, on the 
contrarj, to increase in size. The nauseas became more frequent, and 
the more marked efforts, which precede vomiting, appeared. Vomiting 
finally took place, and then 1 felt mj finger pressed with a force trulj 
extraordinary. The stomach rid itself of a part of the aliments it 
contained ; but I distinguished no sensible contraction in it. The 
nau«ea having ceased for a short time, 1 enlarged the opening in the 
linea alba^ for the purpose of observing the stomach. As soon as the 
incision was enlarged, the stomach presented itself at it, and made an 
effort to come out of the abdomen ; but I prevented it with my hand. 
The nauseas returned in a few minutes, and I was not a little surprized 
to see the stomach filled with air, as they came on. In a very litUe 
time the organ had become three times its former size ; vomiting soon 
followed this dilatation, and it was evident to all who were present, that 
the stomach had been compressed without having experienced the 
least contraction in its fibres. This organ rid itself of air and of a 
portion of aliments ; but, immediately after the exit of these substances, 
it was flaccid, and it was not till after some ' minutes, that gradually 
contracting, it became nearly of the same dimensions as it was before 
the vomiting. A third vomiting took place, and we saw again the tame 
series of phenomena. 

For the purpose of ascertaining whence the air came, which, during 
the nauseas, distended the stomach, 1 applied a ligature on the stomach 
near the pylorus, so as to close the communication which exists between 
this organ and the small intestines, and I made the dog swallow six 
grains more of emetic in powder. At the end of half an hour the 
vomiting returned, accompanied by the same phenomena. The dis* 
tension of the stomach by air was at least as marked as in the preceding 
experiment ; foetidet there was no appearance of contraction of the 



120 PHYSIOLOGICAL RESEARCHES 

primiiiye character ; and have never been regulated by 
the brain. From whence proceeds this difference in the 

stomach, «lid we could not even clcarij dittiogiiifh iti peritlaJtio 
motion. The animal havinp; been killed tome momenti after, ia mm 
experiment which had no relation to yomitiofc, we examined the abdo- 
men. We saw that the stomach was of considerable sise ; Hs teatvre 
was flaccid and not all contracted ; the ligature, at the pjrlonuy was 
not displaced, and the air had not been able to pass this way. 

Harinf repeated this experiment and ani/ormlj obtained tba mom 
results, I thou^t it right to conclude with Chirac and DuTemej, that 
the mechanical pressure, exerted on the stomach bj the diapbra| 
the abdominal muscles, u much concerned in the production of 
ing ; now, if it were so, by removing this pressure from the stooMdi, 
YOfflittng would be prerented ; experiment confirmed this conjeolart* 

I injected into the vein of a dog four grains of an emetic dbsciHed 
in two ounces of common water, (in I his way Tomiting is prodwsed 
quicker and more certainly ;) I afterwards made an opening in Ika 
abdomen, and when the first efiTorts of roroiting began, I quickly ditw 
o«t the whole of the stomach, which did not prevent the efiTorts of 
Tomiting from eontinuing. The animal made precisely the same dEwlf 
as if be had yomited ; but nothing came from tbe stomach ; this organ 
remained completely immoveable. I wished then to see what wo«M 
be the efiTect of pressure made on the stomach ; for this pnrpoic, 1 
placed my right hand on the anterior face of this organ, and my left bnad 
on the posterior face. The pressure was hardly commenced wbea the 
eflbrts of vomiting, that is to say, the contraction of the diaphragm and 
the abdominal muscles powerfully recommenced. I suspended the 
pressure ; the abdominal muitcles and diaphragm soon suspended their 
contractions. I renewed the pressure ; tbe contractions of the musclée 
began again ; then 1 suspended it ; they ceased ; and seven or eight 
times in succession. The last time, 1 made a strong and continued 
prenure; this produced a real vomiting. A part of tbe snbstaacea 
contained in the stomach was thrown off. I repeated this experiment 
on another dog ; 1 observed the same facts ; only I remarked moreoYer 
that the contractions of the diaphragm and the abdominal musdet ean 
be produced by merely drawing by the œsophagus. 

In the experiment just related, the emetic substance was introdocad 
into tbe veins, and we have already remarked, that the effecU were 
quicker and more certain than if the same substance had been iotro- 
daced into the ftomach. This alone should make us suspect that 



ON LIFE AND DEATH. 121 

pbenonfiena of sensibility and contractility ? I cannot in 
a precise and rigorous manner resolve this question. 

* 

Yonnting is not owing, as is generallj believed, to the impression of thç 
emetiQ on the mucous membrane of the stomach \ (oTy in this case, its 
action ought to have been more prompt when it was placed directlj io 
contact with this membrane, than when it arrived at it with the blood 
after having passed throngb the lungs and the four cavities of the heart. 
For the purpose of elucidating this question and of seeing if the con- 
tractions of the muscles were the result of the impression produced on 
the stomach, or if they were excited more directlj bj the emetic sub- 
stance mixed with the blood, 1 made the following experiment : 

I opened the abdomen of a dog, and haying brought the stomach out 

at the opening, 1 tied with care the yessels that went to this viscus, and 

I removed . the whole of it (I ascertained in some of the preceding 

experiments that a dog can live eight and forty liours after his stomach 

has been removed.) 1 made a suture in the abdominal parietes ; then, 

having laid bare the crural vein» I4njected into its cavity a solution ojt 

two grains of emetic in an ounce and a half of water. I had hardly 

finished the injection when the dog began to have nausea, and he soon 

made all the efforts that an animal does when he vomits. These efforts 

appeared to me to be even more violent and longer continued than in 

ordinary vomiting. The dog remained quiet about a quarter of an 

hour ; I then renewed the injection, and I forced two grains more of 

emetic into the crural vein ; this was followed with the same efforts of 

vomiting. I repeated the experiment many times and always with the 

same success ; but this experiment suggested to me another, whioh I 

performed in the following way : I took a dog of good size, from whom 

I removed the stomach, as I had done in the preceding experiment; I 

introduced into the abdomen a hog^s bladder, to the neck of which I 

had fixed, by threads, a canula^f gum elastic ; I put the end of thli 

canula into the extremity of the œsophagus, and I fixed it there also by 

threads, so that the bladder resembled somewhat the stomach, and was, 

like it, in communication with the oesophagus. I introduced into the 

bladder about a pint of common water ; this distended it, but did not 

fill it completely. A suture was made in the wound of the abdomen, 

and four grains of emetic were injected into the jugular vein. Nausea 

soon appeared, and was followed with real efforts of vomiting ; finally, 

after some minutes» the animal vomited up abundantly the water from 

the bladder. ' 

It followed evidently from the preceding experiments, that th« 
16 



12t PHTSI0L06ICAL RESEARCHES 



VII. Of the extensibility and contractility qf texture, 

m 

I shall now proceed to examine the properties^ whxeh 
depend on texture only, on the organic arrangement of 

abdoniaal nmiclet and the diaphngm eonoorred to prodaoe ¥iMiritiBg t 
bet St ranaiDed to bo aioortaiiiod, what wm tbo port of tho diapbngM. 
kk tbo prodaotioii of thia phonomonoo, and wbot was that oC tiM 
abdominal iniitclefl. 

If tho diaphragm rooeived only diapbragmatio nerroi, it woold be 
oaijr to reriit tho contraotioD of tiiis mofolo by drrtdiDg theio nocrai ; 
bat it alio recolfoa fllamoDti from doffial pairs, and tboso fibuatfttt an 
sufficient to support its contraelioiis. Tot ozporimont shows iM| Ibnf 
tho diaphragmatic nerres being ont, tho contraction of tho diapfamgaa 
b very evidently diminished in power, and it may bo said» wilboot 
hazard of mistake, that this mnsclo loses, by th» division, three 
of its eontraclile force. It was then nselnl to see what indw 
difinon of these nerves would have on tbo production of tbb pi 
■00. I asado this division in the neck of a dog of three years old, ma 
I aAafwards iii()eoted into the jugular vein three grains of emeCio ; tbam 
waa 01^ a very feeble vomiting ; another injection of emetio, a quart» 
of an hour after, excited no vomiting» I opened tho abdomen aai 
endeavoured to produce vomithig by compfosshig tho stomacb. Tbo 
■ compression, though very powerful and long continued, ezoited no 
eiibrt of vomiting ; it did not oven appear to produce nausea» I thought 
that this circumstance might be owing to tho indiosynorasy of tho animal} 
bnt having many times sinoo repeated this experiment, I have never 
obtained any other result. 

In order to understand what part «the abdominal muscles bytheiff 
contractions take in vomiting, we ought to observe what takes place 
when these muscles are unable to act. There is but one way of com- 
ing at this, which is, to separate these muscles from their attachments 
at the sides of the ' linea alba ; this wo have done on many animals ; 
we bav^ detaohed successively tho external oblique^ tlie internal 
obUque and the transversalis, leaving on tho anterior face of the abdo- 
men only the peritoneum. When these muscles are 'thus removed, we 
can see very distinctly through tho peritoneum, all that takes place in 
this cavity; we dutingaish, for example, perfectly the pôisCaltie 
BMtion of the ttomaob and the intestines ; and if the stomacb contnwts 



02f LIFE AND DEATH. Uf 

the fibres of die different parts. These are extensiUIily 
and contractility. 

They both succeed each other, and are connected ia 
tbe^ame way, as in the vital phenomenal the organic and 
animal sensibilities are related to their respectire con* 
tractilities. 

Extensibility of texture, or the fSaiculty of being dis- 
tended beyond the ordinary state by external impulse 
(and in this it is distinguished from the extensibility of 

it win be eat J to see it. The abdominal moicles being thus detached, I 
injected three grains of emetic into the jagnlar rein, and also immedi- 
atelj nausea and Tomiting jtock place bj the eontraction of the dia- 
phragm alone. It was oorioos to see, in the conTuIsive contraction of 
th» muscle, the whole intestinal mass poshed downwards, and pressing 
strongly against the peritonenm, which was mptored in some, places. 
In this case, the linea alba, formed bj a Tery strong fibrous textore, is 
the only part whidi resists the pressore of the riscera ; its existence 
then is indispensable to the action of TomHing; perhaps it performs an 
analogoos office in the ordinary state. This experiment proves tiM 
▼omiting can be produced by the efforts of the diaphn^ga akXM | Ifeii 
ii also coirfrmef by the following experiment : 

I detached, as above, the abdominal muscles and laid bare the perito^ 
«eum ; 1 afterwards diWdeid the diaphragmatic nerves, and injected an 
emetic into the veins* The animal had some nausea, but nothing more. 
Though I repeated many times the injection of the emetic, I never was 
able to produce any sensible effort of vomiting. 

From the different experiments that we have just related, and from 
the facts that we made known in a preceding note relative to the 
motions of the œsophagus, we may conclude, without any haf ard, 

Ist. That Tomiting can take place without any contraction of the 
stomach. 

2d. That the pressure exerted immediately on the stomaph by the 
diaphragm and abdominal muscles, appears to be sufficient to produce 
vomiting, when Ihe occlusion of the inferior part of the oesophagus offers 
no obstacle to it. 

3d. That the convulsive contraction of the diaphragm and abdominal 
muscles, in vomiting from tartarized antimony and emetic éubstances 
properly so called, is the result of a direct action of these substances 
on the nervous system and independent of the impression felt by the 
stomach. 



124 PHYSIOLOGICAL RESEARCHES 

the irisy* the corpora cavemosa^&c.) This extensibility^ 
I say^ belongs to many organs. The extensor muscles 
are very much lengthened in strong tension of the limbs; 
the skin accommodates itself to tumours ; the aponea- 
ToseSy as we see in ascites and pregnancy, are distended 
by what is accumulated beneath them. The mucous 
membranes of the intestines, of the bladder ; the serous 
membranes of the greater number of the cavities present 
us with similar phenomena, when these cavities are fall* 
The fibrous membranes, the bones themselves are suscep- 
tible of distension. Thus in hydrocephalus the pericra- 
nium, and the bones of the craniuqi, in spina ventosa and 
other analogous diseases, the extremities or the middle 
of the long bones experience a similar distension. The 
kidneys, the brain, and the liver, when abscesses are 
formed in their interior, the spleen and the lungs, when 
penetrated by a great quantity of blood, the ligaments in 
articular dropsies, in short all the organs, under a thousand 
different circumstances, exemplify this prQ|)erty ; a pro?* 
perty inherent in their texture, and not precisely depend- 
ing on their life ; for as long as their texture remains 
untouched, their extensibility subsists also, though they 
themselves have ceased to live. — The decomposition of 
the parti from whatever cause it happens, is the sole term 

* Tbe motions of the iris cannot be attributed to an active expansion 
of an erectile texture ; they are owing to tbe contractions of • two 
muscular lajen>, one of which is radiated and enlarges* the opening of 
the pupil, the other is orbicular and contracts it. 

Tbe motions of the iris, like all those which have muscular contrac- 
tion for their cause, can be excited for a considerable time after death 
bj tbe galvanic fluid. During life, the motions of the pupil are prodnood 
in mut, by tbe more or less vivid impression of light on tbe retina. Bat 
^faey are beyond the influence of the will ; in birds on tbe contrary, they 
appear to be entirely subjected to it. In these animals, we can even 
after death, and on an eye entirely detached from^tbe body, produce 
tbe motions of the iris by pricking the optic nerve. 



ON LIFE AND DEATH. 125 

of this extensibility, in which the organs are passive at 
all times, and subject to the mechanical influence of those 
bodies which act upon tl|em. 

There exists for the dififerent organs a scale of exten- 
sibility, at the top of which are those which have the 
greatest laxity in the arrangement of their fibres, as the 
muscles, the skin, and 'Cellular substance ; at the bottom 
of the scale are those which are characterized by their 
density, as the bones, the cartilages, the tendons, and the 
nails.' 

We must not, however, be deceived by appearances, 
with regard to the extensibility of parts of the body ; for 
the serous membranes, which at the first glance would 
seem to be capable of great distension, do not yield so 
much of themselves, as.frpm the development of their 
folds. Thus the displacement of the skin, which aban- 
dons certain parts, while it spreads over tumours in the 
vicinity, might easily give rise to the supposition of its 
being capable* of a much greater distension than that of 
which it is really susceptible. 

With extensibility of texture, there corresponds a cer- 
tain mode of contractility, which may be designated by 
the name of contractility of texture. This can only take 
place after a previous distension. 

In general the greater number of our organs are main- 
tained in a certain degree of tension from dififerent causes ; 
the locomotive muscles by their antagonists, the hollow 
muscles by the different substances which they enclose ; 
the vessels by the fluids, which circulate within them, 
the skin of a part by that of the neighbouring parts, the 
alveolar parietes by the teeth which they contain. If 
these causes be removed, contraction supervenes ; thus^ 
if a long muscle be cut, its antagonist will be shortened ; 
if a hollow muscle be emptied, it will contract 3 if an 



126 FHTSIOL06ICAL RESEARCHES 

artery be deprived of its blood, it will become a liga- 
ment ; if the skin be cut into, the borders of the incision 
will retire from each other; if a (ooth be drawn, its cavity 
will be obliterated. 

In these cases it is the cessation of the natural ezten* 
sion^ which occasions the contraction ; in other eases it is 
the cessation of an unnatural extension which does so. 
Thus, the lower belly is straitened after puncture or 
delivery ; the maxillary sinus, after the extirpation of a 
fungus ; the cellular texture^ after the opening .of an 
abscess, the tunica vaginalis, after the operation of hydro- 
cele, the skin of the scrotum, after the extirpation of the 
voluminous testicle, by which it was distended ; the sac 
of an aneurism, after the evacuation of the fluid. 

This mode of contractility is not by any means depend- 
ent on life ; it belongs only to the texture, to the organic 
arrangement of the part,* yet still receives from the vital 
powers an increase of energy. Thus the retraction ù[ a 
muscle, which is cut in the dead subject, is much snaalkr 
than that of a muscle divided in the living animal ; in 
the same way,* the retraction of the skin varies ; but 
though less evident, this contractility subsists always, 
and like its corresponding extensibility has no other limit 
than that of the decomposition of the part. 

* When a patient dies after barini^ for a long time been dtprifed of 
lolid and liquid nonrishment» it is not rare to find in him the itoMith 
and intestines considerably lessened in their two dimensions, the intenuil 
caTitj almost entirely effaced, the length being hardly a third of what 
it was before the disease. We truly say then with Bichat that b a 
contraction from a want of extension. But that this mode of con* 
tractility is as he says perfectly independent of life and owing only to 
the arrangement of parts, is what cannot be admitted. If it wen ae 
in fact, by emptying the stomach after death, we might prodaoe a con- 
traction sinniar to that which is produced during life. . Now ezperiment 
chows OS, that this does not take place. Thé stomach when emptied 
remains fiacctd, and doee not eontract in an j perceptible degree* 



■■^"- 



ON Lire AND DEATH. 127 

The gretter number of authors have confounded the 
phenomena of this contractility with those of the insensi- 
ble organic contractility, or tonicity. Of these I might 
reckon Haller, Blumenbach, Barthez and others, who 
have referred to the same principle the return upon them- 
selves of the abdominal parietèsi after distension, the 
retraction of the skin, or a divided muscle, and the con- 
traction of the dartos from cold. The first of these 
jriienomena is owing to the contractility depending on 
texture, which does not suppose the application of an 
irritating substance; the second, to tonicity, which is 
never exercised excepting when influenced by such appli- 
cation. 

Neither have I myself, in mj treatise on the mem- 
branes, sufiSciently distinguished these two modifications 
of contraction, but we evidently ought to establish be- 
tween them the most decided limits. 

An example will render this more sensible. Let us- 
take for it an organ, in whieh there may be observed 
all the kinds of contractility, of which I have hitherto 
spoken ; a voluntary muscle for instance : In distinguish- 
ing the species with precision we may acquire a clear and 
precise idea, of each of them. 

. Now such muàde may enter into action firstHby the 
influence of the nerves, which it receives from the brain y 
here it shews its animal contractility. Secondly, it may 
be brought into action by the stimulus of a physical or 
chemical agent applied to it, a stimulus, which artificially 
creates a motion, analogous. to that, which is natural to 
the heart, and other involuntary muscles ; — ^here we have 
the sensible organic contractility or irritability. Thirdly, 
its action may be produced by the influx of fluids, which 
penetrate all its par^ for the purpose of carrying thither 
the matter of iuitrition> and which at the same time are 



12S PHYSIOLOGICAL RESEARCHES 

the occasion of a partial oscillatory movement in each 
fibre, in each molecule, a movement as necessary to the 
function of nutrition, as in the glands it is indispensable 
to the process of secretion, or in the lymphatics to that 
of absorption.* Such action we refer to the insensible 
organic contractility or tonicity : Fourthly, by the trans-, 
verse section of the substance or body of the muscle, 
may be determined the retraction of its two ends towards 
their points of insertion. Here the contractility of its 
texture is displayed. 

Any one of tHese kinds of contractility may cease to 
exist in a muscle and the others may not be affected. 
Cut its nerves, and there will be no longer any animal 
contractility ; but the two modifications of its orguic 
contractility will continue to subsist. Impregnate the 
muscle with opium, suffer its vessels to be well pene- 
trated with this substance and it will cease to contract 
under the impression of stimuli, it will lose its irrita- 
bility, but it will continue to possess the tonic move- 
ments, which are occasioned by the influx of blood into 
it Lastly, kill the animal, or rather let it live, but tie 
the vessels which go to the limb, and the muscle will in 
such case lose its tonic power and possess its contractility 
of texl4;ire only. The latter will only cease on the super- 
vention of sphacelus. 

By these examples the different kinds of contractility 
may be appreciated with respect to the organs where they 
are assembled in a smaller number than in the Dnuscles of 
volition ; in the heart for instance and in the intestines, 

* IVe know that the organs are nonriibed, that the glands secrete, 
we know that certain yessels absorb (whether they be the Ijmpbatios 
or not,) bat we do not know, that all this is produced by a partial 
oteiUatory tnovenunt in each fihrt^ in each moleeule. No one can ba 
certain that this moTement takes place, becanie no one hu seen it« 



■- 



ON LIFE AND DEATH. 129 

where there exists a sensible and insensible contractility, 
the organic being retrenched ; and again in the tendons, 
aponeuroses, and bones, where the animal and sensible 
organic contractilities are wanting, the insensible organic 
and the contractility of texture only remaining. 

In general these two last are inherent in every kind 
of organ, the two first belonging to some in particular 
only; hence for the general character of living parts 
we must choose the* insensible organic contractility or 
tonicity, and for the character of all organized parts 
whatsoever, whether living or dead, the contractility of 
texture.* 

We shall farther remark, that this last in the same way 
as its corresponding extensibility possesses them, has its 
different degrees, its scale of intensity, the skin and the 
cellular substance on. .the one hand, the tendons, the apo- 
neuroses, and the bones on the other, forming the extremes 
of this scale. 

From all that has been said, it is easy to perceive, that 
in the contractility of every organ there are two things 
to be considered, namely the contractility, or the faculty, 
and the cause, which puts it in action. The contractility 
is always the same, belongs to the organ, is inherent in 
it, but the cause which determines its exercise may be 
various^ 

• Why iqvcnt a new word, when #e have that of elasticîtj, which 
expresses for all bodies whether organio or inorganic, that tendency to , 
resume their usual form and size, when the cause that made thenr change 
them is no longer in exercise P ' 



17 



f 

1ft Vital— ^ 



I 



- 



130 PrfYSIOLOOICAL RESEARCHES 

VIII. Recapitulation qf the properties of living bodies, 

A récapitulation of these properties may be seen in the 
following table : 

Cioftei. Oeiufû. Speeitê» VoHeHu* 

L Ist Animal 
lit Sensibility — < 

f 2d Organic 

1 1st Animal 
9d Contractility— < C Ist S^aiUe 

f Sd Organic— < 

f 2d InaeoiiliU 
Ist Extensibility 
2d of Texture— < 

2d Contractility 

I have not inserted in this table that modification of 
motion, which takes place in the iris, the corpora caver- 
nosa, &c. a motion, which precedes the influx of the 
blood, and which is not in such way occasioned, neither 
have I mentioned the dilatation of the heart,* and in a 
word that species of active and vital excitability, of whieh 
some parts appear to be susceptible, and my reason for 
this neglect, although I recognise the reality of the modi- 
fication, is my want of clear and precise ideas on the 
subject. 

From the properties, which I have now explained, are 
derived dl the functions, all the phenomena, which are 
exemplified in the living œconomy. There is not one, 
which may not be traced to them after a strict analysis, 

* Bichat here nnites three sorts of motion which have no relation 
between them ; the systole of the carities of the heart should be con- 
sidered as a really actiTe dilatation. The increase of size of the corpora, 
cavernosa, which is an effect purely passive of the accumulatioa of 
blood in those parts, and which can be produced after death by artiff* 
cially accelerating the circulation in them ; and finally, the motion of 
the iris, a motion evidently produced by a muscular contraction, exoila- 
bl« by galTaniim or pricking the nerve. 



ON LIFE AND DEATH. 181 

in the same manner as in the phenomena of physics we 
recur to the properties of attraction , elasticity, &c. 

Wherever the vital properties are in action, there is a 
.disengagement, and a loss of caloric peculiar to the animal, 
which compose for him a temperature independent of the 
medium in which he lives. The word caloricity will 
>hardly serve for the expression of this fact, which is a 
general effect of the two great vital powers in a state of 
action, and not produced by any especial faculty distinct 
from them. We- do not make use of the words, digesti- 
bility, or 'respirability, because digestion and respiratioa 
are the results of functions derived from the common 
laws of the system. 

For the same reason the digestive power of Grimaud 
suggests an inaccurate idea. The assimilation of hetero- 
geneous substances to our organs, is not the effect of any 
peculiar power. The same may be said of the different 
principles admitted by a number of authors, who have 
attributed to results and functions denominations expres- 
sive of laws, and vital properties. 

The proper life of each organ is composed of the differ- 
ent modifications, to which are submitted in each of them 
the vital sensibilities and mobilities, modifications, which 
invariably are productive of others in the circulation and 
temperature of the organ. Let it hb noticed however, 
that each organ independently of the general sensibility, 
mobility, temperature, and circulation of the body, has 
a particular mode of sensation and heat, together with a 
capillary circulation, which being withdrawn from the 
influence of the heart, receives the influence only of the 
tonic action of the part.''^ But we may pass over a 

* Without deaying the influencé which the capillary systems of the 
different organs have on the circulation» we have shown that even in 
the veins the action t>f the heart is felt «nd modifies the course of the 
blood. 



138 PHYSIOLOGICAL RESEARCHES 

point 80 frequently and sufficiently discussed by other 
authors. 

Let it here be understood that I ofifer what I have satd 
on the subject of the vital powers, only as a simple view 
of the different modifications, which they experience in 
the two lives. These detached ideas will in a short time 
form the basis of a more extensive work. 

Neither have I recapitulated the different divisions of 
the vital powers, which have been adopted by authors ; 
the reader will find them in their works, and will easily 
perceive the differences, which distinguish thein from 
those, which I have adopted. I shall only observe that 
were these divisions clear and precise, did they suggest 
to all the same meaning, we should not have to regret in 
the writings of Haller, Lecat, Wyth, Haen, and all the 
physicians of Montpellier, a number of disputes of.no 
importance to the interest of science, and surely fatiguing 
to the student. 



CHAPTER VIII. 

OF THE ORIGIN AND DEVELOPMENT OF THE ANIMAL LIFS. 

If there be any circumstance, which establishes a real 
line of demarcation between the two lives, this circum- 
stance undoubtedly is the mode and epoch of their origin. 
The organic life is active from the very first moment of 
our existence; the animal life begins after birth only; 
for without external excitants the latter is as necessarily 
condemned to inaction, as without the fluids of the œco- 
noray, which are its internal excitants, the former would 
become extinct. But the subject, on which wq are now 



Oî^ LIFE AND DEATH. 133 

engaged deserves a more. particular discussion, and in the 
first place let us examine, in what manner the animal life, 
which for some time is absolutely null, is born as it were 
and developed. ' 

I. In the fœtus the first order of the funotions of the 
animal life is not as yet in action. 

The instant, at which the foetus. besoins to exist, is nearly 
that of its conception ; but this existence, the sphere of 
which is every day enlarged, is not the same as that, 
which the child is destined to enjoy after birth* 

The state, in which the fœtus exists while in the womb, 
has been compar-cd to that of a profound sleep. Such 
comparison is inexact. In a state of sleep the animal 
life is only in part suspended. In the foetus it has not 
commenced. We have seen in fact, that this life is made 
up of the simultaneous or distinct exercise of the senses, 
of the nerves, of the brain, of the organs of locomotion, 
and the voice. Now in these différent functions every 
thing in such state is inactive. 

Every sensation* supposes the action of external bodies 
upon our own, together with the perception of such 
action; a perception which takes place by virtue of the. 
sensibility of the system, which is either general or par- 
ticular, for tfie tact is the faculty of perceiving general 
impressions, and has for its object to warn us of the 
presence of bodies, together with their common attri- 
butes, such as heat, cold, dryness, or humidity, hardness 
or softness.. To perceive the particular modifications of 
bodies is the business of the senses. 

Has the fœtus in utero any general sensations ? To 
decide this question, let us enqufre whether any impres- 
sions are capable there of exercising its tact. The fœtus 



134 PHYSIOLOGICAL RCSBARCHCS 

lives in a temperature at all times the same, swims in « 
•fluid, and is thrown from time to time against the parietes 
of the womb : such are the three sources of its general 
sensations. 

We shall now remark, that the two former are next to 
nothing, and that the fœtus cannot have a consciousness 
of the medium, in which it is nourished, nor of the heat^ 
by which it is penetrated, for every sensation supposes a 
comparison between an actual and a past state of being. 
We are sensible of cold, only because we have experi- 
enced an antecedent heat ; were the temperature of the 
atmosphere invariable, we should have no idea whatever 
of temperature. The Laplander enjoys himself in a 
climate, which would be pain, and death to the N^ro, if 
suddenly transported thither. It is not at the time of the 
solstices, but at that of the equinoxes, that our sensations 
of heat, and cold are the most lively. The reason of 
which must be, that at the latter seasons, their varieties 
are more numerous, and occasion more frequent coBipari- 
sons between that, which we feel and that which we have 
felt. 

What we have now said of temperature, we may repeat 
with respect to the waters of the amnios : the fœtus can- 
not be sensible of their influence, because the contact of 
any other medium is unknown to it. Before bathing, 
we are not sensible of the air, after bathing, the impres- 
sion made by it upon us is unpleasant. It then affeets us 
because there has been an interruption of its action upon 
the cutaneous organ. 

la the shock of the parietes of the matrix a more real 
cause of excitement, than the waters of the amnios, or 
temperature ? At first we might be inclined to answer 
this question in the affirmative, because the fœtus being 
only at intervals subject to such stimulus, there should 



ON LIFE AND DEATH. 135 

appear to result from thence a sensation. But let u^ 
remark that the density* of the uterus in a state of preg- 
nancy being little greater than that of its waters, the 
impression must be trifling. In fact the more the con- 
sistence of bodies resembles that of the medium in which 
we live, the less powerful will be their action upon us. 
Water for instance, when reduced into vapour in our 
Gomnxon fogs, and mists, afiects the tact but slightly ; in 
proportion as it is condensed it is the cause of a livelier 
aflection. 

The air then, to the animal which breathes, is truly the 
general comparative-, term^ to which he refers all the sen- 
sations of tact. If the hand be plunged into carbonic 
acid gas, such substance will not affect the tact because its 
density is little different from that of the air. 

The variety then of these sensations is in proportion to 
the difference existing between the density of the air, and 
that of the bodies, which are the occasion of such sensa- 
tions. In the same way, the measure of the sensation 
of the fœtus must be the excess of density in the matrix 
above that of its waters. Now such excess being very 
inconsiderable, the sensation of it must be very obtuse. 

This assertion with respect to the foetus will become 
more general if we add to it the following : namely, that 
the nlkueous membranes, which are the seat of an inward 
tact have not as yet begun to exercise their functions. 
These membranes, after birth, being ' continually in con- 
tact with extraneous substances, possess in these bodies 

* It is unfortunate that Bichat makes use of the word density, as be 
seems to be ignorant of its true signification. 

The resistance, which the womb offers to the fœtos that strikes 
against it, is wholly independent of density, and results only from the 
greater or less flexibility of its parietes. Cork is much less dense than 
mercury, and yet it offenio the flngér, when pressed agiainst it, a mack 
greater resistance* 



136 PHYSIOLOGICAL RESEARCHES 

80 many causes of irritation, which being continually 
repeated» become excitants to the organs : but in the 
fœtus there is no succession in these causes. The same 
urine, the same meconium, the same mucus at all times 
exercise their action upon the bladder, the intestines, and 
pituitary membrane. 

From all this we may conclude, that the general sen- 
sations of the fœtus are very inconsiderable, though it 
should appear that the child in this state is surrounded by 
many of the causes, which are hereafter to beget sensations. 
Neither are the particular sensations of the fœtus more ac- 
tive ; indeed they cannot be so for their causes are absent 

The eye which is closed by the pupillary membrane, 
and the nostrils, which are scarcely indicated, would not 
be capable of receiving impressions, even in the supposi- 
tion that light and odour could act upon them. Applied 
against the palate, the tongue is in contact with nottiing 
capable of producing savour. Were it in contact with 
the waters of the atnnios, the effect would be the same, 
because as we have said, there is no sensation, where 
there is no variety of impression. The saliva of one 
person to another person possesses savour, to the indi- 
vidual himself it is insipid. 

The ear in like manner is awakened by no sound. All 
is calm, every thing reposes with the little individual. 

Here then we have proved, that four of the ga'tes of 
sensation are' shut in the fœtus ; and let us now observe 
that the nullity of action in the senses which we have 
mentioned, must occasion very nearly the same nullity 
with respect to that of the touch.* 

* Of these four sources of sensation, the first, whatever Bichat may 
say, exists in the fœtus before birth, and the other three, do not exist 
some hoyrs after ; the eye is intensible to light, the ear to toand, and 
the taste is not really in exercise when the first food creates in the 
organ an unaccustomed sensation. 






ON LIFE AND DEATH. 



137 



In fact, this sense is especially destined to confirm the 
notions which are acquired by the others, and to rectify 
them, for the latter are frequently illusory — the touch is 
always the agent of truth.* In attributing to the touch 
such use, nature has submitted it directly to the will; 
light, odours, and sounds affect their respective organs 
independently of the will. 

The exercise of the other senses precedes that of the 
touch,' they are the occasion of it. If a man were bom 
without sight, hearing, smell, or taste, can we conceive 
in what way, he would be possessed of the sense of touch? 

The fœtus^ resembles such a man ; it possesses where- 
withal to exercise the touch in its hands, which are 
already developed, and in the parietes of the matrix. 
Nevertheiless the fœtus is never in action, because in 
seeing, in hearing, in smelling, and in tasting nothings 
it is not disposed tp exercise the touch in any way. Its 
members are little better than what to the tree are its 

* Philosophers and physiologists accord to the touch a great preemi* 

nencé over the other senses. The senses of seeing, smelling and hear« 

ing are, say they, the sources of a thousand illusions. The touch alone 

is exempt from them, and even- rectifies the errors which come from 

elsewhere; Ihe touch it the sense of reoto»» It is undoubtedJy a 

delightful prerogative ; but let us see if it is iDcontestdble. And first 

does the touch never deceive us ? All children know an experiment 

which proves the contrary. If we cross two fingers of the same hand, 

and place in the angular space between their extremities a bmall body 

which touches both of them, the touch will give the sensatioD of two 

distinct bodies. It is then true that the touch may become a cause of 

errors ; it no doubt serves to rectify those of the other senses, but do 

not these in their torn often defend us from the errors of the touch ? If 

the tight were not almost constantly in exercise, the errors of touch 

would be much more numerous; we can judge of them by what we 

experience when we are in the dark. If we were to take from one 

man the use of his eyes, and from another that of his hands and tho 

exercise of touch ai much as pMsible, we should see which would be 

the most embarrassed, which would make the most hhe judgmentfl. 

18 



ISS PHYSIOLOGICAL RESEARCHES 

branches, which do not transmit the impression of the 
bodies, with which they are entangled. 

I shall here notice a great difference between the tact 
and the touch; they were formerly confounded by physi- 
ologists ; the impressions of the latter are always directed 
by the will, those of the former do not depend on it* We 
shall conclude that the portion of the animal life which 
constitutes sensation, does not exist in the fœtus. 

This nullity of action in the senses supposes the same 
deficiency of action in the nerves, which belong to them, 
and in that of the brain from whence they issue ; for 
the business of the former is to transmit, of the latter 
to receive. Now without objects for transmission and' 
reception, the two functions cannot have place. 

From perception are immediately derived the memory 
and imagination; from these the powers of the judgment 
and the will. All this series of faculties then has not had 
a beginning in the fœtus, because the fœtus has not per- 
ceived, or had sensation. The brain exists in a state of 
expectation, it possesses all that is requisite for 'action. 
It does not want excitability, but stimulus. The first 
division of the animal life in consequence, or that, which 
relates to the action of exterior bodies, on the animal, 
has scarcely an outline in the fœtus. Let us examine 
whether the saoie be true of the second division of the 
animal life, or that which relates to the reaction of the liv- 
ing body. 

11. Locomotion exists^ but belongs in the fœtus to the 

organic life. 

When we see the strict connexion which exists in 
animals, between sensation and their voluntary efforts, 
tre might be induced to believe, that voluntary motiok 






ON LIFE AND DEATH. 139 

increases or diminishes with the increase or diminution 
of sentiment ; for as sentiment furnishes out the materials 
of the will, when it does not exist, volition cannot exist: 
from induction to induction, it might thus be proved that 
in the fœtus the muscles must be totally inactive. 

Nevertheless the fœtus moves, and sometimes even 
very strong shocks are the result of its motions. The 
reason why it does not produce sound, is because the 
medium for the production, of sound is wanting. But 
how can we ally the inertia of the first part of the animal 
life with the activity of the second. It is thus. 

We have seen in speaking of the passions, that the 
muscles of locomotion are brought into action in two 
manners» ist, by the will ; 2dly, by sympathy. This 
last mode of action occurs, when from the affection of an 
inward organ the brain is affected also, and occasions a 
motion which, in such case, is involuntary. A passion, foi: 
instance, affects the liver, the liver the br^in, the brain 
the voluntary muscles. Here it is the liver, not the 
brain, which is the principle of motion : so that the 
muscles, though always thrown into action, immediately 
from the irradiations of the brain, belong nevertheless, as 
to their functions, sometimes to the one life, sometimes 
to the other. 

Hence it is easy to conceive in what way the fœtus 
moves t with the fœtus, locomotion is not a portion of 
the animal life ; its exercise does not suppose a pre-exis- 
tent will ; it is purely a sympathelic effect. 

In utero the phenomena of the organic life succeed 
each other with an extreme rapidity ; a thousand differ- 
ent motions are incessantly connected in the organs of 
circulation and nutrition. In these, every thing is ener- 
getically in action. But this activity of the organic life 
supposes a frequent influence exerted upon the brain by 



140 PHYSIOLOGICAL RESEARCHES 

the inward organs, and consequently as many reactions 
on the part of the brain by sympathy upon the muscles; 
Besides, the brain is at such time more susceptible of 
guch sort of influence, being much more developed than 
the other organs, and entirely passive on the side of the 
sensations. 

We may now conceive what the motions of the foetus 
are. They belong to the same class as many of those 
of the adult, which have not been as yet sufficiently 
distinguished. They are the same as thos& which are 
produced in the voluntary muscles by the passions ; they 
resemble those of the man who sleeps, and who moves 
without dreaming, for nothing is more common than 
violent agitation in sleep succeeding difficult digestion. 
The stomach is in strong action; it acts upon the Urain; 
the brain upon the muscles. 

I might find a number of other involuntary organic 
motions taking place in the voluntary muscles of the 
adult, and consequently adducible to my present purpose; 
but what I have said on this subject will suffice. Let us 
remark only, that the organic motions, as well as the 
sympathetic afiection of the brain, which is the seat of 
them, must gradually dispose this organ, and the muscles 
of the fœtus, the one to the perception of sensations, and 
the other to the motions of the animal life, which are to 
commence after birth. But on this head \ shall refer to 
the miemoirs of Monsieur Cabanis. 

From what has been said, then, I believe we may con- 
fidently assert, that in the fœtus the animal life does not 
exist, and that all the actions which take place at this- 
age, depend upon the organic life. The fœtus, indeed, 
has nothing of the especial character of the animal. Its 
very existence is that of the vegetable ; and its destruc- 
tion can only be said to be that of a living body, not of aa 



.\:-Jt 



ON LIFE AND DEATH. 141 

animated being. Thus, in the cruel alterniative of sacri- 
ficing the life of the mother, or that of the child, the 
choice cannot be doubtful. 

The crime of destroying a fellow-creature is much 
more relative to his animal, than to his organic life. — 
We regret the being who feels, who reflects, who wills, 
who. acts accordingly, and not the being which breathes, 
which is nourished,' which is the seat of the circulation 
and the secretions. It is the former, whose violent death 
is accompanied with those images of horror, under which 
we look on homicide. In proportion then as in the series 
of animals, their intellectual functions diminish, is dimin- 
ished also the painful sentiment which we feel at sight of 
their destruction. 

If the blow, which terminates by an assassination the 
life of a man, were to destroy his organic life only, and 
sufier the other to subsist without alteration, such blow 
would be regarded with indifference, woulc) excite neither 
pity for the victim, nor horror against the aggressor. 

III. Development of the animal life, education of its 

organs. 

A new mode of existence commences for the infant 
after birth; a variety of functions are added to .its organic 
life; their aggregate become more complicated; their 
results are multiplied. As for the animal life, it only 
begins; and at this period a number of relations arc 
established between the little individual and what sur- 
rounds him. It is then that every thing assumes with 
him a difierent mode of being, but at this remarkable 
epoch of the two lives, where the one is augmented by 
almost the half,^ and where the other commences only, 
they take upon ^them both a distinct character, and the 



142 PHTSIOLOGICAL RESEARCHES 

aggniDdisement of the first by no means follows the same 
laws as the development of the second. 

We shall soon remark, that the organs of the internal 
life attain at once their perfection, and that from the 
instant at which they begin to act, they act with as much 
precision as they ever will do. On the contrary, the 
organs of the external life require a species of education; 
they arrive only by degrees at the perfection which we 
afterwards see in them. This important difference should 
be thoroughly examined. Let us begin by appreciating 
of what the animal life at first consists. 

In examining the different functions of this life, which 
start at once into existence, we shall observe in their 
development a slow and graduated progress.*^ We shall 
see, that it is insensibly and by means of a real education 
that the organs attain a precision of action. 

The sensations are at first confused ; they transmit only 
general images ; the eye has only the sensation of light ; 
the ear that of sound only ; the nose only that of smdL 
As yet there is nothing distinct in these general affec- 
tions of the senses ; but from habit the strength of the 
first impression is lessened and the particular sensations 
take place. The great differences of colours, sounds, 
smells, and savours, become perceptible ; by little and 
little their secondary differences also are perceived, and 
after a certain lapse of time the child has learnt to see^ to 
hear, to smell, to taste, and to touch. 

After successfully undergoing the operation for the 
cataract, the patient, who has previously been totally 
blind, is sensible of light only, and learns by gradation 
to distinguish the objects which reflect it. Another per» 
son, before whom, as I have said, for the first time if 
exhibited the magnificent spectacle of an opera, at the 
first glance^ perceives only a whole, which delights hinii 



« -.v.'^Ufei;. 



ON LIFE AND DEATH. 143 

^ and only by degrees is able to isolate the enjoyments of 
which the dance^ the music, and the decorations are pro- 
ductive. 

The education of the brain is similar to that of th» 
senses. Whatever depends upon its action, acquires the 
perfection, to which it is destined, by degrees only. The 
powers of- perception, memory and imagination, which 
are all of them preceded and occasioned by the sensa- 
tions, increase and extend in proportion as by repeated 
excitement they are brought into exercise. — The judg- 
ment, of which they form the triple base, associates but 
irregularly at first its motions, which themselves are but 
irregular. In a short time a greater degree of perspi- 
cuity is observed in its operations, and lastly they become 
precise and rigorous.. 

The voice and the agents of locomotion exemplify the 
same phenomenon : the cries of young animals at first 
are only an unformed sound, which possesses no sort of 
character : by age they are gradually modified, and after 
long repeated exercise affect the peculiar consonances of 
the species, by which, and particularly during the season 
of their loves, the individual of the same species is never 
deceived.* I dp not instance the speech of man, for this 
is evidently the fruit of education. 

In examining the newly born animal, its muscles will 
be seen continually in action. As every thing is new to 
it, every thing is an excitant to it, and makes it move ; it 

*^Thi8 assertiou is not correct, and the vorce, at the earliest age» bas. 
consonances peculiar, not only to the species, but even to tbe indi- 
vidual. The man accustomed to Ihe very striking difierinces of the 
articulate sounds of speech or tbe distinct sounds of music, distinguisbe» 
with difficulty the differences in cries ; but tbe animals to whom the 
cry is the habitual medium of expression are not deceived in the same 
way ; the ewt, la the midst of a whole flock, distinguishes the voice of 
her lamb, and thii loonleami to recogniie tbe voice of it» mother» 



' • 



« 



144 PHYSIOLOGICAL RESEARCHES 

endeavours to touch every thing, but neither progressioD^ 
nor the power of standing can. have place when the con- 
tractions of the voluntary muscles are so numerous. It 
is necessary for such, that habit shall have taught it 
to combine particular contractions with other particular 
contractions ; until then it stumbles and falls at every 
moment. 

Undoubtedly the inclination of the pelvis in the fœtus, 
the disposition of the femora, and the want of curvature 
in the spine, adapt it but little for standing immediately 
after birth ; but with these causes is certainly also com- 
bined the want of exercise..* Who does not know, that 
if a limb be suffered to remain immoveable for a length 
of time, it loses the habit of moving, and that when 
afterwards its service is required, it requires a new kind 
of education before it can exercise its movements with 
any regularity or precision. The man, who for a long 
time should condemn himself to silence, would experi- 
ence in like manner the same embarrassment in his first 
attempt at utterence. 

From these considerations we may conclude that our 
exterior life, to allow myself the expression-, is learnt, 
and requires before it can be perfected, a sort of appren- 
ticeship. 

IV. Of the influence of society over the education qf 

the organs of the animal life. 

Over this sort of education, which the organs of the 
animal liie receive, society exercises a very great influ- 

* The locomotive organs do not require a long éducation ; ai we fee 
m animals whose organization, at the moment of birth, is no obstacle 
to motion. A joung kid in an hoar after, will stand on its legs, and 
before the end of the day we often see it skipping. The partridfs raai 
as it comes out of the shell. 






ON LIFE AND DEATH. 145 

ence ; it enlarges the sphere of action of some of themi 
lessens it for others, and modifies it in them all. 

I shall first remark, that it constantly gives to some 
of the organs a perfection greater than naturally should 
be their portion. Such in fact is the nature of our occu« 
pations as always to require the especial action of some 
one, or other of these organs. The ear of the musician, 
the palate of the cook, the brain of the philosopher, the 
muscles of the dancer, and the larynx of the singer, 
receive in addition to the general education of the exte- 
rior life, a particular education. 

Under these considerations, the occupations of man» 
kind might be divided into three classes. The first 
would comprehend all those, which especially regard the 
senses, such as painting, music, and sculpture, the acts of 
the perfumer and the cook, and in a word all those the 
results of which are productive of pleasure to the senses. 
In the second would be ranged the occupations, wherein 
the brain is chiefly called into action; such as poetry, 
the sciences of nomenclature, the mathematics and meta- 
physics. The occupations of dancing, equitation, and the 
mechanic acts would form the third class.* 

Each several occupation then of the individual, brings 
into permanent activity, some one organ in particular, 
and gives it a peculiar perfection. The ear of the musi- 
cian in a piece of harmony, and the eye of the painter in 
a picture, distinguish many things which entirely escape 
the vulgar. It frequently happens that this perfection of 

* The idea of classifying buman occupations, according as tbej bring 
in play the oi|^9 of the senses, the intellect or locomotion, is a wild 
and useless one. This division besides is made in a way altogether 
defective, since in the first class it is the result of the occupations which 
put in play the organs^ whatever may be the means of execution ; in 
the second it is the occupation itself, whatever may be the results, and 
in the third, it u at the same time the execution and the result. 

19 



"♦' 



146^ PHYSIOLOGICAL RESEARCHES 

i^tioiii is accompanied in the more exercised organ with 
an excess of nutrition : this we may frequently obserye 
in the muscles of the arm of the baker, in those of the 
inferior limbs of the dancer, and in those of the counte- 
nance of the player. 

In the second place I have asserted that society con- 
tracts the sphere of action, which should naturally belong 
tb many of the external organs. Indeed, for the sole 
reason that any one of them is the more occapied, the. 
others must be less so, and lose in aptitude what is gjained 
by the single organ. The most common observation will 
prove this truth at every moment. 

Examine the philosopher, who in his abstract medit»* 
tions, and in the silence of the closet condemns to inaetioa 
his external and locomotive powers. Examine him by 
chance attempting any exercise of the body, and you will 
laugh at his awkwardness and air of constraint ; 4iis 
sublime conceptions astonish, the heaviness of his moye* 
ments is amusing. 

Examine on the contrary the dancer, who by the light- 
ness of his steps exhibits apparently to the eye whatever 
the graces of fable have set before the imagination. It 
might be imagined perhaps that the profoundest medita- 
tions, have been productive of such felicity of motion ; 
but let him be conversed with, and nothing very surpris- 
ing will be found in the man. 

The observing mind, which analyses the different indi* 
viduals of society at every moment, will be led to similar 
remarks. Perfection of action in the locomotive organs, 
concurring with a like perfection of intellect, will seldom 
be found* 



M.'à-^ 



ON LIFE AND DEATH. I47 

V. Of the lawSj which regulate the education of the 

organs of the animal life. 

It is manifest then that society inverts the natural ordéf 
of éducation in the animal life, and that it irregularly 
distributes to the different organs of this life, a perfection 
which they would otherwise enjoy in a more uniform 
proportion. 

A determined sum of power, has been attributed to 
every individual, which sum must always remain the 
same, whether it be equally or unequally distributed, 
accordingly the activity of one organ must imply more 
or less inactivity in the otheM. 

This truth WiU conduct us to the fundamental princi- 
ples of all social education whatever ; namely, that no 
individual at the same time, should be applied to many 
studies, even if it be wished that he should succeed in 
all of them. Philosophers have long insisted upon this 
maxim, but I doubt whether the moral reasons on which 
they have founded it, are all of them together worth this 
singlcL and beautiful physiological observation by which it 
is demonstrated, that for the purpose of augmenting the 
powers of one organ, there are no other means than those 
of diminishing the powers of the others. On this account 
I shall dwell upon this observation, and prove its truth 
by a variety of facts. 

The ear, and. especially the touch, acquire in the blind 
man, a perfection which would hardly l>e credited, were 
not its reality proved by daily observation^ The deaf 
and dumb possess in the eye an accuracy of sight, which 
is unknown to those, with whoiA the powers of the ear 
and utterance are unfolded. Little connexion with ex- 
ternal objects, enfeebles the' senses of persons whe are 



146 PHYblOLOGICAL RESEARCHES 

subject to ecstasy, but gives the brain a power of con- 
templation, such as to make it appear, that every part of 
the animal life, excepting that organ, during such affec- 
tion is in a state of sleep. 

But what occasion is there for seeking in extraordinary 
ftcts, the proof of a law which the animal in its healthy 
state exemplifies at every moment. Let us consider in 
the series of animals the relative perfection of each organ, 
and it will be seen at once, that where any one of them 
is excellent, the others are less perfect. The eagle, which 
has a very piercing sight, has but a very obtuse sense o^ 
smell ; in the dog, the latter sense is extremely fine, the 
former dull. The sense of hearing is particularly acute 
in the hare, that of touch in the bat ; the cerebral actioa 
predominates in the monkey, and vigour of motion in 
the ferae. 

Every species then possesses some particular division 
of its animal life, in a degree of excellence superior to 
that of the others. Not a single instance will be found, 
where the perfection of one organ does not appear to be 
acquired at the expense of the others. Man in general, 
abstraction being made of every other consideration, hat 
the ear particularly good, and in the natural order of 
things, this must be so ; because his speech, which exer- 
cises the ear incessantly, is for this organ a permanent 
cause of activity, and therefore of perfection. And not 
only in the animal life is this law remarkable ; but it 
appears to have place also, in all the phenomena of the 
organic life. The morbid affection of one of the kidneys, 
of one of the parotid glands, will double the secrotion of 
the other. 

Let us now examine what happens in the process of 
digestion. Each system at such time is the seat of an 
tKaltation of the vital . powers. Immediately after the 



i.'ji 



ON LIFE AND DEAf £k 149 

entry of the alimeDls into the stomach, the action of all 
the gastric viscera is augmented, the povirers of life are 
concentrated about the epigastrium, and abandon the 
organs of the external life; from thence arise, as authors 
have observed, the lassitude, the inaptitude of the sensen 
to the reception of external impressions, the tendency of 
the individual to sleep, and the cold which is so frequently 
felt in the integuments. 

The gastric digestion being completed, the vascular 
succeeds, and the chyle is introduced into the circulatory 
torrent, for the purpose of undergoing the influence of this 
system, and that of respiration ; accordingly the blood- 
vessels and lungs become in their turn, the focus of an 
increased action, the pulse rises, and the movements of 
the thorax are precipitated.* 

It is then the glandular, then the nutrive system which 
enjoy a marked superiority in the state of their vital 
powers. Lastly, when these powers have been succès* 
sively developed, over all the system, they return to the 
organs of the animal life, the senses resume their activity, 

* We know that at a certain period of digestion the pulte rises and 
respiration h accelerated ; we know it, I saj, but we do not know 
the immediate causes of the phenomenon. Is Tt a reason, in fact, 
because a little chjle enters the lacteal vessels that the heart should 
accelerate the course of the blood in a system of vessels entirely distinct 
firom these ? Because afterwards this cbjie, mixed in a small proportion 
with the venous blood, goes with it through the lungs, is it a reason that 
the motions of the lungs should be accelerated ? Undoubtedly not ; 
besides, the acceleration is not successive in these two functions, as- 
Bichat seems to imply. The one is the necessary and immediate con- 
sequence of the other. But why does the action of the heart increase 
in this second period of -digestion ? We cannot tell ; noir do we know 
why it diminishes in the first ; for to think of explaining it by saying 
that the vital forces are then concentrated at the epigastric region, is a 
mere illusion ; it it only changinc; the expression of the pfieuomenon. 
And clqttiing it in a hypothetical fqrm. 






150 PHYSIOLOGICAL RCSEARCHEft 

the functions of the brain their energy, the muscles their 
rigour. Whoever reflects upon what he has experienced 
after a somewhat copious repast, will be easily convinced 
of the truth of these remarks. 

In this way, the whole of the functions represent a 
species of circle, of which the one half belongs to the 
organic, the other to the animal life, the vital powers 
seem successively to traverse these two halves. When 
they are found in one half, the other is proportionably 
deprived of them, nearly in the same manner as every 
thing appears to languish and be reanimated in the two 
portions of the globe, accordingly as the sun refuses, or 
sheds down his beneficent influence. 

Should any farther proof be required of this inequality 
of distribution with regard to the vital powers, we m^lf 
find it in the process of nutrition. This process baft 
always an excess of action in some one of the organs, 
which at such time may be said to live more than the 
others do. In the foetus, the brain and the nerves, the 
inferior members after birth, and at the age of puberty, 
the genital parts and breast appear to grow at the expense 
of the others. 

From such a variety of considerations, we m^ estab- 
lish the following to be a fundamental law of the distribu- 
tion of the vital powers, namely, that when they inerease 
in one part, they decrease in the rest of the living oecon- 
omy, that the sum of them can never be augmented, and 
that they only transfer themselves successively from one 
organ to another. By the help of these general data, it 
is easy to perceive why we cannot at the same timftiiUain 
tp perfection in the various parts of our animal life, why 
we cannot at the same time excel in all the sciences. 

Universality of knowledge in the same individual is is 
chimera ; it is repugnant to the laws of our organisation^ 



--\_, 



ON UF£ AND DEATH. 151 

and if history afford us some few instances of extraordi- 
nary men, who have -thrown an «qual light upon many 
of the sciences, such instances are but so mmny exceptions 
to the common laws of nature ; for who are we, that we 
should venture on the pursuit of many things at once, and 
hope to attain in all of them a perfection, which for the 
most part, even when we have but a single object in view, 
escapes us ? 

Were we capable of follo^P^ing at once a number of 
occupations, such occupations would be those which have 
the greatest analogy among themselves with respect to the 
organs which they bring into exercise : and by restrain- 
ing ourselves in this way within a narrow circle, we may, 
indeed, with a greater degree of facility excel in many 
parts ; but even here the great secret of being superior 
in any one of them, is that of possessing but a mediocrity 
in the others. 

.Let us take, for example, the sciences, which bring 
into action the functions of the brain. We have seen 
that these functions relate especially to the memory, 
which presides over nomenelature ; to the imaginatiopj^ 
under the empire of which, is poetry ; to the attention, 
which is chiefly excited by the details of calculation ; and 
to the judgment^ whose dominion embraces the whole 
of the sciences ùt reasoning. Now it is manifest from 
daily observation, that not one of these different opera- 
tions of the mind is to be developed but at the expense 
of the others. 

The habits of reciting the beauties of Corneille or 
Racine^ we might naturally suppose would enUrge the 
mind of the actor ^ what can be the reason that from such 
habit he does not acquire an energy of conception beyond 
that of the vulgar? The reason depends in part, no doubt, 
upon tho Mtural disposition of the man, but at the same 



159 rHYSIOLOGICAL RESEARCHES 

time may be deduced from the greater efforts of memory^ 
and the faculty of imitation, which such a person is oblig- 
ed to exert : for the purpose of enriching these, the other 
parts of the brain are in a manner plundered. 

Accordingly, when I perceive an individual, desirous 
at the same time of excelling by address of hand, in the 
operations of surgery, by depth of judgment in the prac- 
tice of medicine, by extent of memory in botany, and 
by force of attention in metaphysical contemplation, 
methinks I see a physician, who, for healing a disease, for 
the purpose of expelling, according to the old expression, 
the morbific humour, at the same time undertakes to 
augment the whole of the secretions by the simultaneous 
use of sialagogues, diuretics, sudorifics, emmenagogue^ 
&c. &c. 

But would not the slightest acquaintance with the laws 
of the economy, suffice for hinting to such physician, 
that one gland pours forth a greater quantity of fluid, 
only because the others secrete a less ? Should he not 
know that such a variety of medicines can operate in 
no decided way, and that to exact too much of nature, 
is frequently the means of obtaining nothing? The same 
may be asked of the individual who is desirous of simul- 
taneous perfection, both in the bodily and mental exer- 
cises, who should pretend to double or triple his relative 
life, when nature has willed that he should only have the 
power of detaching from some few of his organs, some 
few degrees of force, which may be added to one or more 
of his other organs, and by no means that of incressing 
the sum of these powers. 

Do we wish that any one organ in particular shall 
attain to perfection, we must condemn the others to 
inaction. We castrate men to change their voices ; it is 
astonishing that the barbarous idea of depriving them 



-'i? 



ON LIFE AND DEATH. 153 

of sight has not been found out also for the purpose of 
rendering them musicians, since it is well known how 
acute the sense of hearing is in the blind. The child, 
who should be destined to music, ceteris paribus, would 
make a much more rapid progress, were his ears to be 
assailed by harmonious sounds only, and every thing 
removed which might be capable of exercising his other 
senses. 

It is a truth, then, that our superiority in such or sueh 
an art and science, may almost always be measured by 
our inferiority in other respects ; and that this general 
maxim which the greater number of the ancient philoso- 
phers have insisted on, but which many of our modern 
ones would willingly overturn, has for its foundation one 
of the great laws of the animal economy, and will ever 
be as immutable as the base on which it rests. 



VI. Of the education of the animal life as to duration» 

The education of the organs of the animal life, is pro- 
longed for a time which we cannot determine, as it is 
influenced by such a variety of circumstances ; but the 
peculiarity of this education consiists in its being the busi- 
ness of each age, to bring to perfection certain organs in 
particular. 

In childhood, the senses more especially are educated ; 

every thing seems to relate to the development of their 

functions. Environed with bodies which are new to 

him, the little individual seeks to know them all ; he 

maintains in a sort of perpetual expectation .those organs 

by which his connexions with what is near him are 

established, and undoubtedly his sensibility is excessively 

developed. His nervous compared with his muscular 

20 



154 PHT3IOLOOICAL RESEARCHES 

system, is proportionally very p^at ; accordingly for the 
dissection of the nerves, we always prefer the bodies of 
ehildren. 

With the education of the senses, the improvement of 
the functions of the brain which relate to sensation is 
necessarily connected. In proportion, then, as the sum 
of the sensations becomes enlarged, the memory and 
imagination begin to come into play. The age which 
follows infancy, is that of the education of those parts of 
the brain in which these faculties are seated. — It is then, 
that there have existed a 8u£Bcient number of antecedent 
sensations for the exercise of the memory, and for the 
discovery of the type of those illusory sensations which 
it is the business of the imagination to assemble. On the 
other hand, the little activity of the judgment at this 
epoch is much in favour of the energy of these two 
bculties ; and then the revolution which puberty brings 
on, the taste which it develops, and the desires which it 
creates, contribute very much to extend the sphere of the 
latter of them. 

When perception, memory, and the imagination have 
been perfected, when their education is finished, that of 
^ the judgment commences, or rather becomes more active, 
for the judgment begins to be exercised upon the very 
first materials, with which it is presented. At this epoch 
the functions of the senses, and partly those of the brain 
have nothing more to acquire, and all the powers of the 
individual, are concentrated upon the education of the 
judgment 

Hence it is manifest, that the first portion of the animal 
life, or that by means of which we are acted on from 
without, and reflect such action, has at each age a divi- 
sion, which is then particularly unfolded. The first age 
is that of the education of the senses, the second that of 



ON LIFE AND DEATH. 15f 

the enlargement of the imagination, the third that of the 
development of the judgment. 

We should never then prescribe the study of the 
sciences, which exact the exercise of the judgment, at an 
age when the senses are especially in action ; but follow 
in our artificial methods of education, the same laws 
which preside over the natural education of the organs. 
The child should be applied to music and design ; the 
adolescent, to the sciences of nomenclature, and the belles 
lettres; the adult, to the exacter sciences, where facts are 
connected by a process of reasoning. The study of logic 
and the mathematics, terminated our ancient plan of edu- 
cation ; it was one advantage at least among its numerous 
imperfections. 

As to the second portion of the animal life, or that by 
means of which the animal reacts upon external bodies^ 
the state of infancy is characterized by the number, thei 
frequency, and feebleness of its motions ; adult age by 
their vigour ; and adolescence by a mixture of the two. 
The voice, however, does not appear to follow these pro- 
portions, but is subject to an influence which proceeds 
especially from the organs of generation. 

I shall not dwell upon the different modifications, 
which with respect to the animal life are derived from 
sex, climate, and season. So many have treated of these 
questions, that it would be difficult to add to what hat 
been said upon them. -^ 

In speaking of the laws of education, as they affect th« 
organs of the external life, I have supposed these organs 
to be in a state of complete integrity, and possessed of 
whatever is necessary to their perfection. — If they be 
feeble or delicate, if any defect of conformation exist in 
them, these laws will only be applicable more or less ; 
for U is manifest that the habit of judging will oot rectify 



156 PHYSIOLOGICAL RESEARCHES 

the judgment, if the brain be badly constituted ; and that 
the frequent exercise of the larynx and voluntary muscles^ 
will never make up for the irregularity of action occa- 
sioned by irregularity of conformation. 



CHAPTER IX, 

Of THE ORIGIN AND DEVELOPMENT OF THE ORGANIC I.IFE. 

We have just now seen that thQ animal life, which ii 
inactive in the fœtus, is developed after birth : we have 
also followed up the particular laws of its development 
On the contrary, the organic life comes into action almost 
as soon as the fœtus is conceived ; for as soon as th« least 
organization is apparent, the little heart will be seen 
protruding its blood on all sides. The heart is tHe first 
formed part, the first in action : now, as all the organie 
phenomena depend upon it, we may readily conceive in 
what way the functions of the inward life are thrown into 
exercise. 

I. Of the mode of the organic life in the fœtus* 

Nevertheless, the organic life of the fœtus, is not the 
same as that which the adult is destined to enjoy. Let 
us enquire into the reason of this difierence. 

We have said that the organic life is the result of two 
great orders of functions, of those namely of assimilation 
and decomposition, so as to form an habitual circle of 
creation and destruction. Now in the fœtus this circle 
is singularly contracted. 



ON LIFE AND DEATH. 157 

For in the first place, the functions of assimilation are 
much fewer in number; the molecules before they arrive 
within the organs which they are destined to create, are 
not submitted to so many actions ^ they penetrate the 
fœtus already elaborated by the digestion, circulation, 
and respiration of the mother. Instead of traversing the 
apparatus of the digestive organs, which at this age appear 
to be almost inactive, they enter at once into the system 
of the circulation ; the road which they have travelled is 
less, it is not requisite that they should be presented to 
the influenxse of respiration ; and accordingly the fœtus 
of the mammalia has in its preliminary organization a 
near analogy with that of the adult reptile, in which but 
a small part of the blood at its issuing from the hearty is 
sent into the vessels of the lungs.* 

* I am persuaded that the still verj obsoare theory of the fœtus might 
be elucidated by that of animals who have a similar organisation. For 
example, in the frog, in whom but little blood goes through the lungs, 
the heart is a simple organ, with a single auricle and ventricle ; there 
is a communication or rather continuity between the two systems, 
yenous and arterial, whilst in the mammalia, the vessels in which the 
red blood circulates do not communicate with those which carry the 
black blood, except it be by the capillaries. 

In the foetus, the foramen ovale and the ductus arteriosus also render 
very evidently the arteries and veins continuous ; in the foetus the heart 
is likewise a simple organ, not formibg, notwithstanding its partitions, 
but one cavity whilst it is double after birth. The two kinds of blood 
mix at this period, as in reptiles. Now, I shall prove hereafter, that in 
the child who has breathed, this mixture would soon be fatal ; that the 
black blood, circulating in the arteries, would very quickly produce 
asphyxia in the animal. Whence arises then this difference ? It cannot 
be studied in the foetus ; it is necessary perhaps to search for it in frogs, 
salamanders and other reptiles, which can, by their organization, be a 
long time deprived of air without dying, a phenomenon which approxi- 
mates them to the mammalia while living in the womb of the mother. 
Till these very important researches are made, the history of respiration 
will be incomplete. 



158 PHYSIOLOGICAL RESEARCHES 

The molecules of nourishment in this way pass almost 
directly from the circulating torrent into the nutritive 
system. The general process of assimilation, then, is 
much less complicated than that of the following age. 

On the other hand, those functions which habitually 
decompose the organs, which clear the system of sub- 
stances already become injurious and foreign to its nature, 
are at this age but very inactive. Neither the pulmonary 
exhalation, nor sweating, nor transpiration have as yet 
eomipenced : the bile, urine, and saliva are but small in 
quantity, if com[lared with what they are destined at a 
future 'time to be, so that the portion of blood from which 
they are to be made in the adult, in the fœtus is almost 
entirely expended on the system of the nutritive organ&i 

The organic system of the fœtus, then, is remarkable-^ 
on the one hand, for the extreme promptitude of its 
assimilation, a promptitude depending on the very small 
number of the functions concurring to that end ; and on 
the other, for the extreme inertia of its decompositiQ^ 
an inertia defiending on the little activity of the differtnt 
functions, which are the agents of this great process. 

It is easy from the foregoing considerations to account 
for the rapidity which characterizes the growth of the 
fœtus ; a rapidity which is manifestly out of all propor^ 
tion with that which takes place at any other age. In- 
deed, while every thing is in favour of the progression of 
the nutritive matter towards the parts where it is destined 
to be put down, every thing at the same time seems to 
oblige such matter to remain in the place where it has 
been deposited, the emunctories of the system being 
wanting. 

To the great simplicity of assimilation in the fostos, 
we may add the great activity of the organs which con- 
tribute to it an activity, which depends upon the more 



ON LIFE AND DEATH. 159 

•onsiderable sum of rital power which they then partake. 
Ail the powers of the economy, indeed, appear to be 
concentrated upon the system of the circulation and nutri- 
tion; the functions of digestion, respiration, secretion and 
exhalation, are exercised but obscurely.* 

If we now observe that the organs of the animal life, 
which are condemned to a necessary inaction, are the seat 
at the same time of a Tery small portion only of vital 
power (the surplus of this being thrown upon the organic 
life) it will be easy to perceive, that almost the whole of 
the powers which are afterwards to be develc^d upon the 
two systems in general, will be then concentrated upon 
those which serve to nourish and compose the different 
parts of the fœtus, and that in consequence the functions 
which concur to the process of nutrition and growth, must 
at that age be the seat of an extreme energy. 

IL Development of the organic life after birth. 

m 

Immediately after birth, the organic life of the child has 
a great addition made to it ; its extent is almost doubled, 
for not only are many of the functions which did not 
before exist at such time added, but those which existed 
previously are much enlarged. Now in this remarkable 
revolution of things, a law directly the contrary of that 
which presides over the animal life is observed ; for the 
organs of this life, whether they be newly brought into 
exercise, or simply receive an increase of action, need 
no education^ they suddenly attain to a perfection, which 
those of the animal life do not acquire, otherwise than by 

* This explanation is no doubt ingenioup, but it is insufficient, MDce 
the causes which Bichat assigns for the rapidity of the growth of the 
foetus cease entirely at the moment of birth, and yet the growth con- 
tinaet for a long time after to be as rapid. 



leO PHTSlOLOOfCAL RESEARCHES 

long habitude. A rapid glance upon the deyelopment of 
this life, will be 8u£Bcient to conyince us of the truth of 
the above obserration. 

At the instant of birth, digestion and respiration, with 
a great part of the exhalations and absorptions commence» 
Now after the first inspirations and expirations ; after the 
elaboration in the stomach of the first milk, which is 
taken in by the infant, as soon as the exhalants of the 
lungs and the skin have once rejected some small portions 
of their respective fluids, the respiratory, the digestive 
and exhalant organs, have as perfect an action as they ever 
will have. 

At the same time all the glands, which slept as it were, 
which poured forth but a very small quantity of fluid, are 
awakened from their torpor by the stimuli of the yarioas 
substances which are applied to the mouths of their excre- 
tory ducts. The passage of the milk at the extremities 
of the stenonian and wartonian ducts, of the chyme at the 
end of the choledochus and the pancreatic duct, the con- 
tact of air with the orifice of the urethra, awaken into 
action the salivary glands, the pancreas, the liver, and the 
kidneys. The air in like manner upon the inner surface 
of the trachea and the nostrils, and the aliments upon 
that of the digestive passages, are the excitants which 
rouse these parts into action.* 

* When two phenomena are seen to follow each other imme^uAéïj, 
we are naturally led to consider one as the cause of the other. Poêi 
hoc ergo propter hoe. It is a form of reasoning which is Terjr often 
abased. Food taken into the month touches the orifice of the mlirwrj 
ducts, the fluid flows out, and it is then concluded that the sàlivaiy 
gland has been excited by the impression made on the extremity of its 
canal. At the moment of birth, the orifice of the urethra is ezpoaed 
to the contact of the air, and soon the kidneys begin to secrete ; then 
it is the impression of the air on the urethra that has produced their 
action. But is not this contact of the food in the one case, and of the 



. '-' •i-t^^---- 



ON LIFE AND DEATH. 161 

It is then also that begin the various excretions of the 
system : now if we examine well the different organs 
which concur to the above mentioned phenomena, we 
shall find that they require no sort of education. 

I shall not inquire into the reason of this difference in 
the development of the two lives. I shall only observe 
that it is out of the power of any one of the inward 
organs, to acquire a marked degree of superiority over 
any other, for the same reason that they all of them attain^ 
immediately upon entering into action, as great a perfec- 
tion as at any time they are destined to possess. 

Nevertheless there is nothing more common than thé 
predominance of one system of the organic life over the 
other systems ; this is sometimes the vascular, sometimes 
the pulmonary apparatus, at other times the organs of 
digestion, and the liver especially, have the greater degree 
of development, and decide on the particular tempera- 
ment of the individual ; but the cause of this sort of 
constitution depends on primitive organization, on the 
structure of the parts, on their conformation. Such supe- 
riority is by no means the effect of exercise or habit, for 
the fœtus and the child display the same phenomena, io 
as much reality though less apparently indeed, than 
adolescence, or manhood. 

In the same way, the debility of any particular system 
of the internal functions, may depend either on original 
constitution, or on some accidental vice or disease, by 



air IB the other an accidental and purely accessory circnmstance ? Do 
we believe, that if bj anj caase the opening of the prepuce was 
entirely obliterated, the secretion of urine would be prevented ? Do 
we not know that if instead of taking into the mouth sayourj food^ it 
is brought near to it, the saliva flows not less, or in vulgar language 
the mouth waters ? There is however no contact, there is not any 
mechanical or chemical impreraion in the orifice of the laliyary docti. 
21 



IQ2 PHYSIOLOGICAL RESEARCHES 

which, while the others have remained untouched, its 
constitution may have been impaired. 

Such then is the great difference of the two lives of 
the animal, with respect to inequality of perfection in the 
organs. In the animal life, the predominance or inferi- 
ority of one system, with relation to the others, depends 
almost entirely upon its activity or inertia, on its habitude 
of acting or not acting. In the oi^nic life on the con- 
trary, such states are immediately connected with the 
texture of the organs, and never with their education. 

From hence also we have the reason why physical 
temperament, and moral character, are not susceptible of 
change from education, which so prodigiously modifies 
the actions of the animal life, for as we have seen, they 
both of them belong to the organic life. 

The character is, if I may so express myself, the physi* 
ognomy of passions ; temperament, that of the ioteraal 
functions : now the one and the other being at all ages 
the same, having a direction which habitude and exercise 
can never alter, it is manifest that thev must ever be 
withdrawn from the influence of education. The vio- 
lence of the temperament may indeed be modenled, for 
the powers of the judgment, and reflection aaj be aug- 
mented, and the animal life sirengtheaed in Hieh way 
as to give it a capacity oi resisting the impulses of the 
organic life ; but to atteznpt an immediate aheratioo of 
thc> character, or of the passioas. which are its haUtnal 
exprt>$skon$« is an enterpr:>e .Analogous to that of the 
physiciuu, who siiould attempt to elevate or depresy(aiid 
that, for the entire lite oi the patient,) the ordinsfy con- 
tracting po^*er$ of the heart and arteries. 

AVe ;jdiould observe to such physician, that the circula- 
tion and respiration, an^ noi u:ider the dominioa of the 
wiU ; and th&t ihey caooot be modincd excepting in 



ON LIFE AND DEATH. i(|S 

ing into a state of disease. The same observation might 
be made to those, who imagine that the character, and 
consequently the passions may be modified, •^i'^ 



CHAPTER X. 

OF THE NATURAL TERMINATION OF THE TWO LITES. 

We have just now seen, that the two lives commence 
at distant epochs ; we have seen them developing them- 
selves according to laws, which are exactly the reverse 
of each other. I shall now attempt to describe them, as 
they terminate ; and this they do in a very different man- 
ner also, assuming characters at such time «as distinct and 
separate, as those which they possess during the periods 
of their activity. In this place, I shall speak of natural 
death only ; those deaths, which originate in accidental 
causes, will be the object of the second part of this work. 

I. In NaiUlral Death the animal life te the first to cease. 

Natural death is remarkable for the following reason 
chiefly: — it terminates the animal life, a long time before 
it puts an end to the organic life. 

He who dies in consequence of a very prolonged old 
age, dies in detail ; his exterior functions are finished^ 
one after the other ; the senses are shut up successively ; 
the ordinary causes of sensation pass over them, and do 
not affect them. 

The sight grows dull and confused ; it ceases at length 
to transmit the images of objects : this is the blindness of 



164 PnTSIOLOOICAL RESEARCHES 

old age ; sounds also, after a certain time, afiect the ear 
confusedly ; the organ at last becomes entirely insensible. 
The cutaneous covering of the body grows hard and dry; 
it is the seat of an obscure and imperfect touch. Besides 
ivhichy the habitude of feeling has blunted the power of 
feeling ; at the same time all the other organs which are 
dependent on the skin, grow weak and perish ; the hair 
falls, it is deprived of the juices by which it was nourish- 
ed : to continue our description, odours make but a feeble 
impression upon the nostrils. 

The taste indeed is a little more kept up ; but let it be 
remarked that this sense is connected with the organic as 
much as with the animal life, and is therefore necessary 
to the internal functions : In this way, when all agreea* 
ble sensations have fled the old man, when their absence 
has already broken in part the connexions, which attach 
him to the world, his taste remains with him still; it is 
the last thread to which is suspended the pleasure of exis- 
tence. 

In this way, isolated in the midst of nature, already 
deprived of the greater number of the functions of the 
sensitive organs, the old man is soon to suffer the loss of 
the common action of the brain, for it is manifest, that 
there can scarcely be any farther perception, for the very- 
reason that there is nothing farther coming from the 
senses. Meanwhile, the imagination lessens and is sooa 
annihilated. 

The memory of present things is destroyed : the old 
man in an instant forgets what is told him, becanse his 
external senses enfeebled and already dead, as it were, 
in no wise confirm what is intimated to him by the mind 
alone« Ideas escape him when the images, which are 
tr»ce«) by the senses* do not keep their hold. On the 
contrary» the remembrance of the past remains with iim. 



ON UFE AND DEATH. 195 

that which .the old man has formerly known, has been 
taught him or at least confirmed to him by his senses.* 

He differs from the child in this respect; the child 
judges only from the sensations which he experiences, 
the old man from those, which he has experienced. 

' The result of the two states is the same, for the judg- 
ment is equally uncertain, whether founded exclusively 
upon actual or past sensation. Its accuracy depends upon 
the due comparison of the two. No one can be igno- 
rant, that in the judgment which we form from visible 
objects, the actual impression would frequently deceive 
us, were we not to rectify the error by what we are 
enabled to recollect, and may we not observe that past 
sensations, in a short time grow confused, if the features 
of the picture, which they have left with us, be not 
retraced by new and analogous impressions ? 

The present then, and the past with regard to sensation, 
are equally necessary for the perfection of the judgment. 
If either the one or the other be wanting there cannot 
be any comparison made between the two, and in conse- 

* jlf the old man preserves with difficulty the memorj of the most 
recent events, whilst he often retraces with the greatest ease the recol- 
lection of the most distant ones, it is not because the first have been 
more faithfully transmitted to him by his senses, but because these 
events had produced a greater impression on him. This is so true, that 
failure of the memory is sometimes remarked in old people who have 
their senses in perfection. On the other hand, yery imperfect sensations 
may produce a very lively impression. A connoisseur in painting, 
when his sight is very bad, experiences in seeing a beautiful picture, a 
hundred times more pleasure, than one who is indifferent to it, though 
he examines it with good eyes, and the connoisseur preserves the image 
of it long after the other has lost it. We do not perceive the recollec- 
tion of things, unless there is some circumstance connected with them 
that makes a lively impression ; but in the same event, this circum- 
stance will not be the same in all individuals, and it is sometimes bj 
the most trifling of all that a man fixes the fact in his memory. 



166 PHTSIOLOOICAL RESEARCHES 

quence there must be a want of precision in the judg- 
ment. 

For these reasons, the first and the latter ages of man, 
are equally remarkable for imbecility. Old age is second 
infancy. The two periods of life resemble each other 
with regard to want of judgment; they differ only as to 
the cause of such defect. 

The interruption of the functions of the brain of the 
old man, is a consequence of the almost entire annihila- 
tion of the sensitive system with him ; in the same way 
does the weakness of the locomotive power, succeed 
almost inevitably to the inactivity of the brain. This 
organ in fact re-acts upon the muscles, in proportion only 
as the senses act upon it. 

The movements of the old man are few and tardy ; he 
changes with difficulty the attitude, into which he has 
thrown himself; seated near the fire, and concentrated 
within himself, a stranger to 'every thing without him^ 
he passes his days there, deprived of desire, of passicHi^ 
and sensation ; speaking little because he is determined 
by nothing to break his silence, yet happy in feeling that 
he still exists, when almost every other sentiment is 
gone. 

The rigidity of the muscles however, and the diminu- 
tion of their contracting powers, is another cause of 
inactivity in the old man, and doubtless has its inflo- 
ence ; but it is by no means the principal one, since the 
heart and the muscular fibres of the intestines^ contract 
the same rigidity, and are deprived of their powers of 
moving, in a very different way from that, in which the 
voluntary muscles lose it. With the voluntary muscles, 
it is not so much the power as the excitant of the power 
which i^ lost. If it were possible to compose a man 
with the senses and brain of old age^ and the muscles of 



\âJ?:ill^LL^. 



ON LIFE AND DEATH. 167 

youth^ the voluntary motions of such man, would hardly 
be more developed for the reasons which I have given. 

From the above it is easy to see that the external func- 
tions of the old man are extinguished by degrees, and 
that his animal life has almost entirely ceased, while his 
organic life is still in activity. . Under this consideration, 
the state of the animal about to suffer a natural death, is 
nearly similar to that of the fœtus in utero, or of the 
vegetable which lives within itself only, and for which 
external nature is absolutely silent. 

If we now recollect that sleep entrenches more than 
a third upon the duration of the animal life, if we add 
to this the total absence of such life for the first nine 
months of existence, and its almost entire inactivity 
during the latter period of existence, it will be easy to 
calculate the great disproportion of its duration, when 
compared with that of the organic life which is exercised 
uninterruptedly. 

But wherefore when we have ceased to exist without, 
do we continue to exist within, since our sensations and 
above all, our powers of locomotion, are especially destin- 
ed to place us in relation with those substances, which are 
to nourish us. Wherefore are those functions enfeebled 
in a greater disproportion than the internal functions, 
and why is there no exact relation in the times of their 
cessation. \ 

I cannot entirely resolve this question. I shall only 
observe that society has an^ especial influence in creating 
this difference ; for man in the midst of his fellow- 
creatures makes a very great use of his animal life ; the 
springs of it are habitually more fatigued than those of 
his organic life, and worn away under the influence of 
society ; the eye by artificial light, the ear by sounds too 
frequently repeated, and above all by those of speech, 



XeS PHYSIOLOGICAL RESEARCHES 

which are wanting to other animals ;* the smell in like 
manner is debilitated by factitious odours, the taste by 
savours, which certainly are not natural, the touch and 
the taet by constant attrition of dress,t and the brain by 
too incessant thinking. 

We live then externally with excess. We abuse our 
animal life ; it is circumscribed by nature within limits 
which are too much enlarged by us for its duration ; thus 
it cannot be surprising that it should cease so soon. In 
fact we have seen the vital powers divided into .two 
orders, the one appertaining to this life, the other to the 
organic life. These two orders may be compared to two 
lights which burn at the same time, and which have only 
a determined quantity of materials for aliment. In which 
case, if the one be agitated by a stronger wind than the 
other is, it must necessarily be the sooner extinguished. 

Yet social influence notwithstanding is very advantage- 
ous to man. It gradually disengages him from those f \ 
bonds which attach him to life, and renders the instant of 
death less terrible. 

The idea of our last hour, is painful only because.it 
puts an end to our animal life. The borders of the tomb 
are beset with terrors, which will all be found to originate 
in the thought of such privation. 

* Thb failare of th« tentes appeart io animait as well as man, and 
it maj be obter? ed in tho«e whom we tuffer to grow old aaoog ot» 
We often tee dogs becominc blind and deaf; and these înfii»ities are 
perhapt more common in them than in man. But as these anhnals 
are rarelj permitted to arrire at extreme old age, we ha?« wok often an 
opportunity of obserring them. 

t By defending the skin from the thock of extcnal bodiet, and by 
preserfing it from the Tarîation of temperature, drest veiy oeitainlj 
prteerret its sensibility, and iar from impairing the tense of touch, as 
Biohat iMkitaiw, it acta as a cncuMtance &roarablt to its 

tiOA« 



^ 






ON LIFE AND DEATH. 169 

It is not the pain of death, which we fear ; how many 
dying men are there for whom the gift of existence would 
be precious, though purchased at the expense of an unin- 
terrupted series of suffering ! If we look at thfi animal 
which lives but little externally, he by no means trembles 
at beholding the instant of his death.* 

Were it possible to suppose a man, who in dying 
should lose his internal functions only, such man would 
look upon his death with an indifferent eye, because he 
would feel that the blessings of existence, are attach- 
ed to the powers of feeling the influence of nature and 
society. 

If the animal life then be terminated gradually, if each 
of the bonds by which we are capable of the pleasures of 
living, be broken by little and little, such pleasures will 
escape us imperceptibly, and the old man will have for- 
gotten the value of life, when it is about to be taken from 
him ; such destruction will resemble that of the vegetable 
only. 

TI. Ttie Organic Life in natural death does not termi» 
nate as it does in accidental death. 

The organic life remains with the old man after the 
almost total loss of his animal life, and terminates in a 
very different manner from that which is exemplified in 
the case of violent and sudden death. The latter has 
two periods, the first of which is marked by the sudden 
cessation of respiration and the circulation, the second 

* The animal no doubt does not tremble at the moment of death ; 
for he doM not see it. His present sensation is everj thing to him. If 
he soffers at the approach of death, he showt it by the nsnal signs ; bat 
it is only the present pain that he expresses, he sees nothing beyond. 
The child is in this respect, in the same situation as the animal. 

22 



170 PHYSIOLOGICAL RESEARCHES 

by the slow and gradual extinction of the other organic 
fanctions. 

The parictes of the stomach, for instance, continue to 
act upon the aliment which may be found there, the juices 
of the stomach continue to dissolve it. The experiments 
of the English and Italian physicians upon absorption, 
(experiments the whole of which I have repeated) have 
proved that this function not unfrequently remains in a 
state of activity, after the general death of the body, and 
if not as long as some have supposed, at least for a very 
considerable interval. Discharges of urine and feces are 
often observed to take place many hours after sudden 
death. 

The process of nutrition also continues to be manifest 
in the hair and in the nails; the same would doubtless be 
the case in all the other parts^ as well as in the secretions, 
could we observe the insensible movements of which their 
functions are the result. The heart of the frog being 
taken away, the capillary circulation may still be seen 
under the influence of the tonic powers. The body is 
very slow also in losing its animal heat.* 

* la order to ascerf ain the cause of the differences io the cooliog 
of the bodj after the various kinds of death, it is necessarj to examine 
what general conditions can have an influence in the cooling of % bodj 
left to itself. Of these there are three principal ones. 

Under the same external circumstances, a bodj will cool so much the 
slower. 1st. As its temperature at the beginning of the experiment, 
shall be higher in relation to that of surrounding bodies ; Sd. As its 
surface shall be less in relation to its ^ize ; 3d. And as its exterior parts 
shall be less perfect conductors of heat. 

In order to see how the first condition is modified in dififerent cases, 
it is necessary to recollect what is the source of animal heat. The 
blood is warmed in passing through the lungs in consequence of the 
chemical phenomena of respiration ; and as from the lungs it is carried 
to all parts of the body, it yields to the different organs a portion of 
the heat whiob it has recei?ed. Hence the general temperature of the 



vjI 



ON LIFE AND DEATH. 171 

I might augment the above observations with a number 
of others^ which would go to prove the same assertions; on 

body will be higher in proportion to the temperature of the blood, to 
the frequency with which this fluid is renewed in the organs and to 
the quantity of it that is brought to them, at each pulsation. 

Now in diseases of Jong duration, the volume of blood is considerably 
diininished, the activity of the heart is lessened, and respiration is per- 
formed in an imperfect manner. Thus the body of the patient who 
sjnkf under these circumstances has less heat to lose than that of the 
roan who dies suddenly, when all these functions were performed in 
perfection. 

Let ns pass now to the second condition. The cooling, as we have 
said, takes place so much the quicker as the «urface of the body is the 
more extended in proportion to its size.; now, in the emaciation which 
accompanies almost all diseases that are protracted, ihe size decreases 
much more rapidly than the surface. Thus then, when even at the 
moment of death the general temperature of the body may be as high as 
in a state of health, the cooling would however take place more quickly. 

It remains for us now only to examine under what circumstances the 
third condition is fulfilled in the most advantageous manner. When 
an individual in full health dies, the sub-cutaneous cellular Gesture 
usually contains a greater or less quantity of fat. Now we know that 
it is one of the characters of all fat substances to be very bad conduc- 
tors of heat. Hence then a third reason which should render cooling 
more slow after sadden deaths. Sometimes after a disease, this last 
condition is fulfilled in another manner. In certain derangements of 
the circulation, the cellular texture is filled with serum; and as aN 
•qneous fluids are bad conductors of caloric, though the temperature 
of the body may not be very high at the moment of death, the heat is 
yet preserved for a long time. 

To the diflerent causes which we have just mentioned, there is some- 
times added another which is peculiar to one kind of sudden death. 
It is observed that in the midst of the same external circumstance^, 
the blood does not always cool with the same quickness, and that in 
proportion as its coagulation is slower, its heat is longer preserved. 
Now, it is a well known fact, that when death is the result of asphyxia, 
t-fae vessels are found full of fluid blood ; this is also a reason which 
contributes to explain the slowness of the cooling. And it should be 
remarked, that asphyxia is one of the most frequent causes of sudden 
death either accidental or voluntary. 



172 PHYSIOLOGICAL RESEARCHES ON LIFE AND DEATH. 

the contrary, in the detth which is the eflTect of old age^ 
the whole of the functions cease, because they hare each 
of them been successively extinguished. The vital pow- 
ers abandon each organ by degrees, digestion languishes, 
the secretions and the absorptions are finished, the capil- 
lary secretions become embarrassed ; lastly, the general 
circulation is suppressed. The heart is the ultimum 
moriens. 

Such, then, is the great difierence which distinguishes 
the death of the old man, from that which is the effect of 
a sudden blow. In the one, the powers of life b^n to 
be extinguished in all the parts, and cease at the heart; 
the body dies from the circumference towards the centre: 
in the other, life becomes extinct at the heart, and after- 
wards in the parts. The phenomena of death are seen 
extending themselves from the centre to the circumfer- 
ence. 




BICHAT ON LIFE AND DEATH. 



FART TBB SBOOm. 



CHAPTER L 



GENERAL CONSIDERATIONS ON DEATH* 

In the first part of this work, I have explained the 
two great divisions of life, together with the remarkable 
differences, which distinguish the animal existing without, 
from the animal existing within. I have discussed the 
characters which are exclusively proper to the two lives, 
and the particular laws, according to which they both of 
them commence, are developed and end in the natural 
order. 

In this second part I shall inquire in what way they 
accidentally finish, in what way their course is prema- 
turely arrested. 

The influence of society suffers us but rarely to live 
out the period which was intended us by nature ; while 
almost every other animal attains his natural end, such 
end in the human species is become a sort of phenomenon. 
The different kinds then of accidental death, should engage 
the particular attention of the physician and physiolgist. 
Now this sort of death may happen in two ways : some- 
times it is ther esult of great disturbance excited in the 
economy ; and sometimes it is the effect of disease. 

In general it is easy enough to discover, according to 
what laws the functions are terminated in conseqMMe of 



1 



• I * ' 



174 PHTSIOLOOICAL RESEARCHES 

any violent or sudden attack ; of apoplexyi for instance, 
great hemorrhagy, concussion of the brain, or asphyxia ; 
because in such cases the organs of the body, excepting 
that which is immediately affected, are not the seat of 
any peculiar lesion» and cease to act from causes diametri- 
cally the contrary of those, which according to the com- 
mon course of things maintain them in action. Now as 
these causes are partly known, their contraries may be 
inferred ; besides, we are capable of imitating these sorts 
of death upon animals, and consequently of analyzing, 
experimentally, their different phenomena. 

On the other hand it is seldom in our power to produce 
artificially in the bodies of animals the diseases of the 
human species. Were we even possessed of such power, 
we should gain but little knowledge from it: the laws of 
life in fact are so changed, so modified, so altered in their 
very nature, by the various morbid affections to which 
the parts are subject, that but very seldom can we depart 
from the known phenomena of the living animal, when 
we undertake to inquire into those which it exhibits 
in its dying moments. For such inquiries it would be 
necessary to know what is that intermediate state between 
health and death, in which the functions experience so 
remarkable a change ; a change, which has such infinite 
varieties, and produces such innumerable sorts of disease- 
But, where shall we find the physician, who will assert 
that from the actual data of his art, he understands in 
such intermediate state, the profoundly hidden operations 
of nature ? 

In these researches then, we shall occupy ourselves 
more especially on those sorts of death which I first 
enumerated. Those, which have been mentioned in the 
preceding paragraph will engage us only now and then : 
besides, at my age I cannot be supposed to have acquired 



ON LIFE AND DEATH. 175 

a sufficient degree of medical knowledge to treat of them 
with advantage. 

The first remark, which the observation of the different 
kinds of sudden death suggests, is, that in all of them the 
organic life to a certain point may subsist, the animal life 
being extinct ; but that the latter is entirely dependent, 
and lasts not for a moment after the interruption of the 
former. The individual, who is struck with apoplexy 
may live internally for many days after the stroke, exter- 
nally he is dead : In this case death commences with the 
animal life : if on the contrary it exerts its influence in 
the first place upon any of the essential organic func- 
tions — as on the circulation in wounds or on respiration 
in the asphyxias — ^the animal life is gone at once, together 
with the sensible actions of the organic life. 

The red and warm-blooded animal, loses his external 
life at the moment when he ceases to exist internally, 
the cessation of the phenomena of his organic life is a 
sure index of his general death; indeed the reality of 
death can be pronounced only from such datum ; the 
interruption of the external phenomena of life is in almost 
every instance fallacious. 

On what depends this difference of the manner in 
which the two lives accidentally end ? It is owing to the 
mode of that influence, which they exercise the one over 
the other^ to the kind of bond, by which they are con* 
nected. 

This mode of influence, this bond, appears to exist 
between the brain on the part of the animal life and the 
lungs, or heart on the part of the organic life. The action 
of one of these three organs is essentially necessary to 
that of the two others ; and as they constitute the three 
centres, in which are terminated all the secondary phe- 
nomena of the two lives, whenever they cease to act, the^ 



US PHYSIOLOGICAL RESEARCHES 

phenomena which depend upon them most cease dso^ and 
general death ensue. 

Physiolofçists have been at all times acquainted with the 
importance of this triple focus ; and hare giren the name 
of vital to all those functions, which have their seat in it. 
Under the point of view which at present engages our 
attention their ideas on this head are well worthy of 
notice, for every species of sudden death begins by the 
interruption t>f the circulation, the respiration, or action 
of the brain. In the first place, one of the three functions 
ceases, then the others successively; so that to expose 
with precision the phenomena of sudden death, we must 
consider them as they take place in the three principal 
organs, which we have mentioned. 

We shall first inquire into those deaths, which begin 
at the heart, and afterwards into those, which begin in 
the lungs and in the brain. I shall explain in what way, 
when one of these organs is affected, the others die; and 
then demonstrate by what sort of mechanism the death 
of the various other parts of the body ensuses. Lastly I 
shall determine from the principles, which I shall then 
have laid down, the nature of the different species of 
disease, which are peculiar to the heart, the lungs,, and 
the brain. 



CHAPTER II. 

or THE INFLUENCE OF THE DEATH OF THE HEART, OVXK 

THAT OF THE BRAIN. 

I SHALL evidently have determined what is the mode of 
influence^ should I be enabled to establish in what 



ON LIF£ AND DEATH. |iri 

way the action of the heart is necessary to that of the 
brain ; for in this instance the cause of death will be no 
other than the privation of the cause of life. Now the 
heart can only act upon the brain in two ways ; by the 
nerves, or the vessels which serve as their connecting 
medium. In fact these two organs have no other means 
of communication. 

It is evident that the nerves cannot be the agents of 
such actions ; it is the province of the brain to act by 
means of the nerves. The different parts of the body 
never influence the brain by such means, excepting in 
the sympathies. If a bundle of nerves belonging to the 
voluntary muscles be tied, the muscles indeed will cease 
to act, but nothing will be changed in the cerebral 
mass.* 

I have ascertained by many experiments that the phe- 
nomena of galvanism, which are propagated so energeti- 
cally from the brain towards the organs, which descend, 
if I may so express myself, along the nerve, will hardly 
ascend in a contrary direction. Apply the apparatus to 
a nerve of the loins and the muscles of the upper limbs, 
and when the communication is made, there will be 
scarcely any contraction ; but on the establishment of a 
communication between the same nerve and the lower 
limbs, a violent convulsive motioti will instantly be occa- 
sioned. I have even observed, on placing two metallic 
plates, the one under the lumbar nerves, and the other 
under the upper limbs, that the communication of the 
two plates by means of a third metal, will cause a con- 

* It ia not trae that a ligature on a nerve produces it& effects only on 
the part to which this nerve is diitributed ; the brain is also affected ; 
for, without this, how can be explained the pain that is felt, and the 
excitement, which is often sufficiently powerful to produce convulsion», 
and tometiffies even death. 

23 



ITS PHTSI0L06ICAL RESEARCHES 

tnetioD of the lower limbs, while the upper limbs remaiD 
inactive, or move bat feeble.* 

These experiments are particularly applicable to the 
relation of the heart with the brain; for not only is it true 
that the section, ligature or compression of the cardiac 
nerves are of little eflèet with regard to the functions of 
the latter, but it is true also, as we shall presently see, 
that they do not directly modify the movementi of the 
former. We may conclude that the vesseb are the exclu- 
sive agents of the influence of the heart upon the brain. 

The vessels, as every one knows, are of two sorts-» 
venous or arterial — ^they carry black or red blood, the 
latter answer to the left side, the former to the right side 
of the heart Now their functions being very different, 
the action of one of the portions of this organ on the 
brain, can never be the same as that of the other portion. 
We shall inquire in what way they both of them act 
upon it. 

In naming these two portions, I shall not make use of 
the expressions of right and left to distinguish them, but 
of those of the red-blooded and the black-blooded heart, 
for each of these portions of itself is an isolated organ, 
distinct from that to which it is applied, and in the adult 
especially so. In iact there are two hearts, the one arte- 
rial, the other venous, notwithstanding which, we can 
hardly employ these adjectives for the purpose of desig- 
nating them, since they both alike possess their arterial and 
venous appendages. On the other hand, they are neither 
of them situated exactly to the right or to the left, are 

*Th6 factf reUled here bj Bichat are not coDformable to those, 
which, the philofophen and phytiologisti have obferred who have been 
more particnlarly engaged wiUi tiib kmd of experimenti. Besidet the 
conseqacnoes which he has drawn from them are not accurate, and 
he seemi to be ignorant what coarse the galranic floid in this case takes. 



Off LIFE AND DEATH. 179 

neither of them exactly forwards or backwards. Besides 
which these latter denominations would not apply to 
animals. 

I. In what way does the ceêaation of the functions of 
the red-blooded heart intermq^t the functions of the 
brain f 

The red-blooded ventricle and auricle, exert their influ- 
ence upon the brain by means of the fluid which they 
send thither through the carotid and vertebral arteries. 
This fluid may excite the cerebral organ in two ways. 
1st. By the movement, with which it is directed. 2nd. 
By the nature of its colouring principle. 

It is easy to prove that the movement of the blood is 
necessary to the life of the brain. Expose the brain of 
an animal in part, and tie the carotids. In such case the 
eerebral movement will be sometimes weakened, and then 
the animal will be stupified, at other times the vertebral 
arteries will exactly .supply the place of the carotids, and 
then there will be nothing deranged in the principal 
functions of the brain ; for there is always a relation 
existing between the alternate rise and fall of the cerebral 
mass, and the energy of life which it displays.* 

In general, the obliteration of the carotids is never 
Suddenly mortal. Animals will live without them^ at 
least for a certain time. I have kept dogs in this state 



* If tiiere is always a relation between the vital energy of the brain 
and its alternate motions, it is because there is a constant relation 
between these motions and the entrance of the blood into the organ. 
Thus then» instead of considering this shock as the exciting cause of 
the brain is it not more natural to see in it only an effect purely aoci* 
dental of the arrival of the arterial blood, which every thing proves to 
be the real excitant? 



180 PHTSIOLOGICAL RESEARCHES 

fbr several days aâd have afterwards made use of them 
for other experiments : two however died in the course 
of six hours, after the application of the ligatures. 

After having made the above experiments which go 
very far to the establishment of the principle which I am 
labouring to prove, let a piece of the cranium be taken 
from another animal and tie the vertebral and carotid arte- 
ries. The movement of the brain will then be entirely 
interrupted and the animal immediately die. 

The impulse, which proceeds then from the influx of 
the blood into the brain, is a condition essential to the 
functions of this organ, but other proofs may bé adduced, 
for the establishment of the truth of this assertion. 

Ist. There are a number of compressions, which can 
only act by preventing the brain from being duly affected 
by such impulse. A collection of pus, or blood, will 
often put a stop to all the functions, which relate to the 
perception, memory, and voluntary motions of the indi- 
vidual. Let such compression be removed and his sensi- 
bility will immediately re-appear. ; In such case, it is 
manifest that the brain was not disorganized, but only 
compressed, and in a state incapable of being excited by 
the heart.* 

I do not think it necessary on this subject to cite cases. 
All authors, who have treated of wounds of the head, are 
full of them. I shall content myself with remarking, 
that the same effect may be artificially produced in our 
experiments upon animals, and that accordingly as the 
brain is compressed or free^ the creature will be insensi- 

* As we know absolatelj Dotbing of the manner in which the intel- 
lectual phenomena are produced in the brain, we cannot lay whether 
compression prevents their derelopment bj stopping the motions with 
which the brain is habitnaUj agitated, or bj preventing the entrance 
of the arterial blood, or finaUy in some other way that we do not suspect. 



OH LIFE AND DEATH* 181 

ble^ or the contrary. According to the degree of the 
compression, will be the degree of the stupor. 

Sdly. There are reptiles, in the brain of which no 
motion whatever is occasioned by the heart. The frog 
is- of this species. On raising the upper portion of the 
cranium, and exposing the brain, there cannot be per- 
ceived the slightest motion. Now in this species, and 
that of the salamander, the influx of blood may be cut off 
from the cerebral organ without occasioning the imme- 
diate death of the animal. The voluntary muscles for 
instance continue to act ; the eyes to exhibit a lively ap- 
pearance, the tact also of the creature is manifest for some 
time after the heart has been taken away, or the double 
branch which proceeds from the single ventricle of these 
animals has been tied.* I have frequently repeated these 
experiments, and have constantly found the effect the 

same. 

3rd. It is a general observation, that those animals 
which have a long neck, and in which the heart for that 
very reason is not so capable of exerting a lively influ- 
ence over the brain, have a more limited intellect, and 
the cerebral functions less marked. On the contrary a 
very short neck, and the approximation of the heart to 
the brain very generally are found to coincide with the 
latter. Similar phenomena are sometimes observed in 
men. They who have the neck particularly long are 
dull, they who have it short, for the most part intelligent 
and lively. 

* The organization of these animals differs too much from that of man 
to enable us to draw conclusions from one to the other, especially in 
what concerns the functions of the nervous system. There is an expe- 
riment of yi. Dumeril in which a salamander lived a long time after the 
amputation of the head, till the formation of a perfect cicatrix in the 
necky which intercepted the passage of air to the lungs. 



las PHYSIOLOGICAL RESEARCHES 

From these many facts we may confidently assert, that 
one of the means, by which the heart maintains the brain 
in action, consists in the habitual movement, which it 
impresses on it* 

But this movement is essentially di£Eerent from that 
which in the other viscera, such as the liver, or spleen, 
is derived from the same cause. In these it is little 
manifest, in the brain it is very apparent ; the reason is 
evident; the large arterial trunks of the brain, are situated 
at its base, between the brain and its bony parietes ; 
in consequence of which , at each diastole, the vessels 
experience a resistance from the bone, which is commu- 
nicated immediately to the cerebral mass. At such time 
the brain is really lifted, just in the same way as we see a 
tumour lifted by the arteries which creep along the bones 
beneath it ; and instances of this are frequent So appa- 
rent indeed is the motion of tumours when they are 
situated over the carotid, as it lies upon the vertebral 
column, or over the femoral artery, immediately after its 
passage under the crural arch, as often to occasion doubts 
with respect to their nature. 

But no other organ is enclosed within a bony cavity ; 
the motion of the arteries every where else, is lost in 
the surrounding cellular substance, or soft parts. Such 
motion, then^ is unessential to the functions of the liver» 
the kidney, and other analogous viscera. 

The integrity of the functions of the brain, is not only 
dependent on the mere motion, but on the sum also of 
the motion communicated. It is equally impaired by too 
much, or by too little motion. Of this assertion the 
following experiments are proofs. 

1st. Inject water by the carotid of a dog; the presence 
of this fluid in the brain is not pernicious, and the animal 
will live very well, when the injection has been skilfully 



• 
L. ■ - 



ON LIFE AND DEATH. 1^3 

made^ But if it be pushed with violence» the cerebral 
action will immediately be troubled, and often cannot be 
restored.* In every experiment, there will be found to 
exist a relation between the force of the impulse and the 
state of the brain; if the pressure be but a little augment- 
ed, its effects will be instantly seen in the agitation of the 
countenance of tbç creature ; if relaxed, a corresponding 
calm will succeed ; if increased to the highest pitch, it 
will immediately occasion death. 

2dly. If the brain be exposed, and an artery afterwards 
opened, so as to produce a considerable hemorrhage, the 
motion of the brain will be diminished in proportion as 
the afflux of the blood to it is diminished, and finally 
will cease entirely. Now, according to all these various 
degrees of diminution, which may be observed in th# 
movements of the brain, will be the corresponding weak« 
ness of the cerebral influence as it is discoverable in the 
state of the eyes, the touch, and the voluntary motion of 
the animal.f 

Hence it is easy to see, why a state of prostration and 
languor is always the consequence of great hemorrhage — 

* Why are not the cerebral functions disturbed, when water is pushed 
slowljr into the carotids ? because there is then mixed with the blood 
of the artery too small a quantity of water at a time to enable this fluid 
to have a very evident action on the brain. But if this introductioB 
of water into the mass of blood continues, whatever precaution may 
be taken, its effects soon show themselves. We have often, in our 
experiments, introduced a great quantity of water into the veins of an 
animal» and though much of it passed off by pulmonary transpiration, 
the arterial blood soon became very aqueous. Now, we have always 
observed, that in this case, the animals were struck with a kind of 
stupidity, which evidently indicated a want of action of the brain. 

I It is not uncommon to see patients, who retain their intelleetoal 
faculties perfectly, when the motions of the heart are so feebtop tftat 
Ihey certainly cannot produce, in the mass of brain, any sensible jar. 



IM PHTSIQLOGICAL RESEARCHES 

and from what has been said above we may conceive the 
reason, why the arterial system of the brain has been at 
first concentrated at its base, while the larger venous 
trunks are almost all of them situated on the convexity 
of its surface. The base of the brain is small and easily 
moved, the convexity large and little capable of trans- 
mitting motion, such as could be made upon it by vessels. 
Besides, it is at the lower part of the brain that exist its 
particular and essential forms. The lesions of these are 
mortal, and consequently their functions must be impor- 
tant. On the contrary, experiment and observation alike 
have proved, that very little derangement follows, from 
cutting or rending the substance of the upper part of this 
organ. Hence also we may see the reason, why its 
natural defences towards its base, are constituted in such 
way as to be almost impenetrable, and why at its uj^r 
surface, it is less protected. Now, where its life is indis- 
pensable, and its action absolutely necessary, it should 
naturally receive the first and undiminished impulse of 
its excitant. We may conclude, that the interruption 
of the action of the red-blooded heart is the occasion of 
interruption in the action of the brain by annihilating its 
•movement. 

But this movement is not the only means by which 
the influence of the heart is exerted on the brain ; for if 
it were so, we might easily reanimate the enfeebled funo- 
4ions of the latter, by injecting it with water at the same 
time through both the carotids. If pushed with an equal 
fQrce, the black blood and the red blood alike would be 
capable of keeping up its action ; but this, as we shall 
presently see, is not the fact. 

The heart, then, acts upon the brain by the nature of 
the fluid which it sends thither ; but as the lungs are the 
focus, where the blood undergoes an alteration^ we shall 



V 



àH; 



ON LIFE AND DEATH. 185 

refer the examination of its influence upon the cephalic 
system, to the chapter in which we shall treat of the 
relation of this system, with that of the lungs. 



II. In what way does the cessation of the functions of 
the hlack'Uooded heart interrupt the functions of 
the brain? 

It very rarely happens that general death commences 
by that of the venous auricle and ventricle. On the 
contrary, they are* almost always the last in action, and 
when they cease to act, the brain, the lungs, and the red- 
blooded heart have already ceased to exhibit their respec* 
tive phenomena. Nevertheless the contraction of these 
cavities may be annihilated, or rendered at least ineffica- 
cious with regard to the circulation, from the rupture of 
an aneurism or similar causes ; in which case the brain 
becomes inactive and dies, as we have shewn it to do in 
the preceding section, from want of movement. 

There is another kind of death of the brain depending 
on the interruption of the transmission of blood from the 
head ,to the heart, as when the jugulars are tied. The 
venous system, in consequence, is glutted and the brain 
compressed, from the continued afflux of the red blood 
into its arteries ; but ^the phenomena of this sort of death 
are already sufficiently known. 

In the present chapter it is my intention to examine a 
species of death, the principle of which by many physi- 
ologists has been placed in the heart, but which appears 
to me to affect the head only ; I mean that death which 
may be occasioned by the injection of air into the 
veins. 

24 



.1 



186 PHYSIOLOGICAL RESEARCHES 

It is generally known, that as soon as any qaantity of 
this fluid is introduced into the vascular system, the move- 
ments of the heart are accelerated, that the creature is 
much agitated, cries with pain, is convulsed, and soon 
after deprived of its animal life, but lives organically for 
a certain time, and then invariably dies.* Now, what 
is the organ so readily affected by the contact of air? I 
a£Srm it to be the brain, and not the heart; and main- 
tain that the circulation is annihilated, only because the 
eerebral actions have previously been so. 

For, in the first place, in this kind of death, the heart 
continues to beat for some time after the cessation of the 
animal life, and consequently for some time after that of 
the action of the brain.t 

Secondly, By injecting air into the brain through one 
of the carotids, I have caused the death of the creature 
just in the same way as when air is introduced into the 



* A very considerable qaantitjr of air can be forced into (he veios of 
an animal, withoat causing its death, provided it be not poshed in 
luddenly. In all these cases, it is understood, that the quantity that 
•an be thus introduced is in proportion to the site of the animal. I 
have before me at this moment the details of an experiment that I made 
on a horse at Alfort with M. Dupui, and in which, before the animal 
died, I was able, in thirtj seven minutes, to inject qoicklj into the 
veins fortj syringes full of air, and three syringes full into the carotid 
artery. (The capacity of the syringe was seventeen centilitres.) The 
animal died three minutes after the last injection. At the ezaminatioD 
of the body, we found air in the azygos vein and in the thoracic duct, 
which contained much lymph, as well as the lymphatic vessels of the 
internal surface of the lungs. The heart was enormously distended 
with air mixed with a small quantity of blood. 

t This is not correct, and death takes place, on the contrary, by the 
cessation of the motions of the heart. The right ventricle is filled with 
air; and this air, dilated by beat, so distends it, that it can no loBfer 
contract. 






ON LIFE AND DEATH. 187 

veins ; excepting only with a prewous palpitation of the 
heart.* 

Thirdly, M orgagni has cited a number of cases of sud- 
den death, the cause of which should appear, from hi^ 
remarks, to be the repletion of the blood vessela of the 
brain by air, which had been developed there spontane- 
ously, and which he says, by its rarefaction, compressed 
the origin of the nerves. I cannot suppose that such 
compression can be effected by the very small quantity 
of air, which, when injected into the carotid, is sufficient 
to occasion death ; accordingly, I should doubt whether 
' this compression were real in the cases adduced, but for 
this, they are not the less important. Whatever be the 
manner in which it kills, air is fatal whenever intro- 
duced into the brain, and this is the essential point. It 
is with the fact that we have to do and not the manner.t 

'^ The disorders which are produced in this case do not at all resem- 
ble those which follow the entrance of air into the veins. If we push 
towards the brain, bj the carotid artery, a small quantity of air, we 
see almost immediately signs of a strong cerebral congestion, spasmodic 
stiffness of the muscles, loss of sensibility, and of the action of the 
senses, and all the phenomena of a real apoplexy. Respiration and 
the circulation go on some time without any apparent alteration, bat 
finally these two functions become embarrassed and the animal sinks. 
Every thing leads to the belief, that the alteration in the circulation of 
the brain depends here on the presence of rarefied air in the ultimate 
arterial ramifications. 

When apoplexy is thus produced by the injection of air, if it be still 
forced into the artery, it breaks open violently a passage for itself it 
tears the small vessels, and spreads in the parenchyma of the brani, 
which it makes emphysematous and crepitating under the finger. 
' There finally returns a portion of it by the veins, which goes to the right 
oavities of the heart and which contributes to arrest the circulation. 

I In the two examinations related by Morgagni, it appears that aAer 
a sudden death, there was found in the vessels of the brain an aeriform 
fluid, to the pretence of which*, for the want of another material eause, 



188 FHYSIOLOOICAL RESEARCHES 

Fourthly 9 As often as an animal is killed by the insuf- 
flation of air into one of its veins, I have ascertained that 

was attributed the death of the individual ; but there it no proof that 
this fluid might not be developed there after death. We shall now 
relate a more decided case of death occasioned by the presence of air 
in the blood vessels ; but here there is no ground for doubt» because 
we know the circumstances of the introduction. 

A locksmith, twenty three years of age, had had for five years a 
large tumour on the right shoulder and clavicle. His acute sufieringt 
induced him to enter the hospital to have it removed. 

It was necessary in the operation to remove the middle portion of the 
clavicle. Thus far the success was complete ; but little blood was los^ 
the pulse was good and the breathing easy, when the patient suddenly 
eried out, Jtfy blood it leaving my body ! I am dead f And at the same 
moment he became stiff, lost his consciousness, and was covered with a 
cold sweat. A singular and rather loud noise was heard in the interor of 
bis chest. The surgeon thought that he had opened the pleura by remov- 
ing a portion of the clavicle, and thus given access to the air and to the 
blood to the right side of the thorax. The fingers of an assistant were 
immediately thrust into the bottom of the wound, with the view of 
stopping the supposed opening in the pleura, and the surgeon endeav- 
oured to introduce into the thorax the extremity of a sound of gum 
elastic. When he thought that he had succeeded, he drew with bis 
mouth the air which he supposed to be effused in the pleura. He wished 
then to proceed to the dressing ; and, in order to do this, he substituted, 
for the fingers of the pupil which were at the bottom of the wound, a 
sponge covered with wax ; but the moment the sponge took the place 
of the fingers, the same noise that was at first heard and which had 
ceased in an instant, was renewed with more force than before. 

The syncope and cold sweat still continued. Water thrown into hie 
face, made him give some signs of life ; but he died a quarter of an 
hour after the appearance of the accident I have just described, and 
forty five minutes after the commencement of the operation. 

The body was examined the next morning. They expected to find 
the right pleura open, much blood and air effused into its cavity and 
the lungs on that side collapsed. Nothing of the kind was found. The 
pleura was whole and there was no effusion in it. The lungs were 
as usual ; but an opening of half an inch in extent was discovered in 
the external jugular vein, at the place where this vein opens into the 
sabclaviaB. The cavitiei of the heart were large but contained do^ 



ON LIFE AND DEATH. igg 

the whole of the red-blooded , as well as the black-blooded 
hearty is full of a frothy blood, mixed with air bubbles ; 

blood. Bubbles of air were observed in the vessels of the brain ; the 
other vessels were not examined. 

This fact was related to me the same day, by a student who wa» 
present. It was impossible forme not to refer the death in this instance 
to the entrance of air into the vessels. The opening in the vein, the 
noise that was heard, the suddenncts of the death, the absence of blood 
in the cavities of the heart, the presence of air in the vessels of the 
brain, all sufficiently indicated it I sujipected that the entrance of 
air had been favoured by the state of tension of the parietes of the 
▼ein, or by their morbid alteration, which did not allow them to flatten 
by atmospheric pressure. I thought that this- phenomenon might be 
produced at will on animals by placing them in the same physical 
circumstances. 1 introduced then into the jugular vein of a dog, a 
aound of gum elastic, and 1 directed it towards the heart. It wai 
hardly there before I heard the air enter the vein, and the animal fell 
down in syncope, with the peculiar noise which manifests the presence 
of air in the heart. I immediately closed the sound to prevent the 
entrance of more air, and the animal gradually recovered, because the 
quantity of air introduced had not been in sufficient quantity to pro* 
duce its death. I then opened the sound, and immediately the air 
rushed in towards the heart, and its entrance was followed by the same 
consequences; but, whether from not closing the sound soon enough, 
or from the entrance of a greater quantify of air, the animal died unex- 
pectedly to me. In opening it, I found all the sign» of death from the 
sudden entrance of air. The right ventricle was distended with air 
mixed with a little blood. 

Sometimes, without any apparent alteration in the texture of the 
veins, its parietes do not flatten under atmospheric pressure ; a simple 
puncture then is Sufficient, as in bleeding, to admit the air into the 
vessels. Lieutaud relates two cases in which it appears that this took 
place, and several veterinary surgeons have assured me that they have 
heard, after bleeding in the jugular vein, a noise which indicates the 
entrance of air. Usually the quantity introduced is too inconsiderable 
to produce any evident eflects. There has been communicated to me, 
• however, a case observed by Mr. Bouley, the younger a veterinary 
surgeon in Paris, in which the entrance of air was followed by eflTects 
similar to those which we have related. 

Mery had long since observed, that, in opening the abdomen of a dogv 



190 FHYSI0LO6ICAL RESEARCHES 

and that the carotids, and vessels of the head, contain a 
similar blood; such blood must act upon the brain, in the 
same manner as it does ia the two sorts of apoplexy, of 
which we have just been making mention. 

Fifthly, If air be pushed into one of the divisions of 
the vena portae from the side of the liver, it oscillates in 
the greater trunks of that organ for a considerable length 
of time, and arrives but slowly at the heart. — ^In this 
instance I have observed, that the animal experiences, 
only after a certain interval, those affections which are 
sudden when the fluid is injected into the veins of the 
principal system.* 

and panctarin^ the rena caTa above the origin of the emnlgenb, as the 
Tein become emptied of blood, it filled with air, which went to the 
right ventricle. Haller also obsenrcd that air entered into the veins of 
Irogs and oUier cold-blooded animals in consequence of a wound of 
•ome large veaseL He has shown that it was from this source that was 
derived that which Redi, Caldesi» and Morgagni saw circulating in the 
vessels of these animals, since it b not observed, when the necessary 
precautions are taken to prerent its introduction. 

Njsten has made a great number of esperiments upon the injection 
of elastic fluids into the veins, and the results which he has obtained 
accord perfectly with those which we have observed. He is not satis- 
fied with injecting atmospheric air, he has introduced in the saose way 
a great number of other gases. He has remarked, that among the gmm 
not deleterious he can introduce, without causing death, a mmek g in ato 
qnantitj if these gases are easilj dissolved in the Uood. 

We cannot follow him in the detail of these experiments ; we shall 
onlj relate a result relative to the colouring of the blood in the In^gi. 
Be has obsenred, that bj injecting air into the vein, so sk>w as Bot to 
produce the death of the animal, the colouring of the arterial bland is 
rendered imperfecL He is satif fied, he sajs, that it is not owing to the 
embarrassment of the lungs. The injection of oxygen does not alter 
this colouring. The injection of aiote completely prevents it ; that of 
the oxide of carbon does not produce anj change in it. 1 give these 
results from his work ; I have not had occasion to Tcriff them mijKlf. 



* When air is introduced into the vena ports, there is not only no 
iD eftct at the awmnt of iiiiectioiiw b«t tlKre nranlly fisUnwa no 



ON LIFE AND DEATH. 191 

Sixthly^ The rapidity with which, in certain experi- 
ments, the annihilation of the cerebral action succeeds to 
the insufSation of air into the veins, might almost per- 
suade us that such phenomenon is occasioned, as it is in 
wounds of the heart and syncope; — but 1st. The most 
simple inspection is sufficient to shew us that the heart 
continues to act after the apparent death of the animal — 
2d]y. As the motions of the heart are prodigiously accele- 
rated by the contact of the foreign fluid, they push on 
the frothy blood with an extreme velocity, and hence we 
have the reason, why the brain in such case is so rapidly 
affected. 

Seventhly, Were the cerebral action in this sort of 
death interrupted for want of movement from the heart, 
it would happen as it does in great hemorrhages of the 
aorta ; that is to say, without violent convulsion. But 
here, on the contrary, the convulsion is extremely vio- 
lent, immediately after the injection, and consequently. 



apparent effect on the animaL It is not the same when air is injected 
into the veins of the general system, with so much care as not to pro- 
dace instantaneous death by the dilatation of the heart. The effects do 
not then appear till along time after the injection ; but they are wholly 
different from the primary effects which we have described. 

These consecutive symptoms from the entrance of air into the veins 
are, as Nysten has remarked, the result of an obstruction of the lungs 
produced by the accumulation of air in the last divisions of the pulmo- 
nary artery. The embarrassment in respiration often appears at the end 
of half a day, it becomes greater and greater, the bronchiae are filled 
with a viscid fluid ; and the animal usually dies on the third or fourth 
day. On examination of the body, no air is found in the heart or the 
vessels ; but the lungs, instead of being pink-coloured, are greyish, 
tinged with brown, and loaded with frothy blood and mucus. 

Boerhaave thought, that death which follows the injection of air into 
the veins was always owing, as it is in this case, to the presence of the 
air, which offers, in the small 'vessels, a mechanical obstacle to the 
passage of the venoiu blood* 



193 PHYSIOLOGICAL RESEARCHES 

announces the presence of an irritating substance on the 
brain. 

We shall conclude, that in the accidental mixture of 
air mth the blood of the venous system, it is the brain 
which dies the first, and that the death of the heart is the 
consequence of the death of the brain. I shall explain 
in another place^ in what way this phenomenon is occa- 
sioned. 



CHAPTER IIL 

OF TH£ INFLUENCE OF THE DEATH OF THE HSABT OYKR 

THAT OF THE LUNGS. 

The lungs are the seat of two very different sorts of 
phenomena. The first, which are entirely mechanical, 
are relative to the rise and fall of the ribs and diaphragm^ 
to the dilatation and contraction of the air vessels, and to 
the entry and exit of the air, which is the effect of these 
movements. The second, which are purely chemical, 
may be referred to the different alterations, wbieh the 
air and blood experience. 

These two sorts of phenomena have a mutual depend- 
ence on each other. Without the mechanical, the chemi- 
cal changes could not be made ; without the chemical 
changes, the blood would cease to become an excitant to 
the brain, in consequence of which that organ would no 
longer operate upon the diaphragm or intercostal muscles; 
the muscles themselves would then become inactive, and 
the motions of the thorax be annihilated. These phe- 
nomena, however, are put an end to in a different manner 



t; 



m * 



ON LIFE AND DEATH. 193 

by the death of Ihe he^rt, accordingly as it happens on 
one or the other side. 

I. In what manner are the actions of the lungs inter^ 
rupted when the black-blooded heart ceases to act? 

The heart has certainly no infikience over the inechani- ~ 
cal functions of the li^ngs, hot it contributes essentially 
to produce the chemical changes which are made there, 
by pending thither the fluid which is destined to undergo 
a change. When its functions then are interrupted as 
may happen from wounds or be occasioned by ligature, 
the chemical changes which should be made in the blood, 
are suddenly suppressed ; though the air continue to 
enter into the lungs, from the dilatation and contraction 
of the chest. 

Meanwhile there arrives nothing at the red-blooded 
heart, or* so little as to be insufficient for the production 
of the cerebral movements. The functions of the brain 
are consequently suspended, and of course the move- 
ments of the diaphragm and ribs. 

II. In what manner are the actions of the lungs inter- 
rupted^ when those of the red-blooded heart are 
Muspended» 

Whenever from wound, ligature, or aneurism, the 
fimctionsof the red-blooded heart or aorta cease, the func- 
tions of the lungs are terminated in the following order : 

* After the obliteration of the duetns afteriotus,- the left rentricle 
receives no blood but what oomes from the lungs ; now, if the motions 
of the thorax continue, H is red blood ; at least so long as the air it 
freely admitted into the bronchial tubes, and so long as the composition 
of this fluid is not changed bj the mixture of foreign gases. 



194 FHTSIOLOGICAL RESEARCHES 

Ist. There is no further impulse made upon the brain*. 
tdly, No further movement of that organ.* 3dly, No 
further action exercised upon the muscles. 4thly, No fur- 
ther contraction of the intercostals or diaphragm. 5thly, 
The mechanical functions of the lungs cease. Sthly, 
Their chemical functions cease. 

In the former case, the chemical chants coald not be 
made for want of blood. Here they cannot be made for 
want of air. ' Such is the difference in the death of the 
lunges, in consequence of that of the heart, according 
as the latter is affected. But as the circulation is very 
rapid, there cannot be but a very short interval between 
the interruption of the chemical and the mechanical func- 
tions of the lungs. / 



CHAPTER IV. 

01* THE INrLirSNC£ OF THE DEATH Ol* THfi HEART OVER 

THAT OF ALL THE ORGANS. 

I SHALL divide this chapter, as the preceding one, into 
two sections. In the first I shall examine, how the death 
of the red-blooded heart, in the second how the death of 
the black-blooded hearty is the cause of the death of all 
the parts of the body. 

I. On the death of the red-blooded hearty and how that 
of the organs is occasioned by it. 

All the functions belong either to the anhnal, or to th^ 
organic life. Hence the difference of their classes. Now 

* These two modifications should, after What we have said, be reduced 
to a single one, vis. want of excitement of the brain by the arteiial blood. 



ON LIFE AND DEATH. 195 

the death of those of the first class, in consequence of 
lesions of the red-blooded auricle and ventricle, is caused 
in two ways, and first, because the brain in such case is 
rendered inert from. want of impulse, and can neither 
have sensations, nor exercise an influence over the loco- 
motive apd vocal organs. 

• Accordingly, all this order of functions is stopped, as 
when the éiicephalic mass has experienced a violent con- 
cussion. It is in this way that a wound of the heart, or 
the bursting of an aneurism, annihilate all oqr relations 
with external objects. . 

So strict a connexion between the u^ovement of the 
heart, and the functions of the animal life, is not observa- 
ble in those animals, in which the brain, in order to act, 
does not require the habitual stroke of the blooc). Tear 
away jthe heart of a reptile, or tie its large vessels, and 
it will continue for a long time to move and have sensa- 
tions. . 

Besides, supposing even that the action of the brain 
were not to be suspended from lesions of the red-blooded 
heart, the animal life would not, on, that account, \ie the 
less put an end to ; because to the exercise of the func- 
tions of this life, is attached as a necessary cause, the 
excitement of its organs by the afflux of blood into them : 
now this excitement, both here and every where else, 
depends upop two causes. — 1st, On the movement impress- 
ed, and 2dly, On the nature of the blood. At present 
I shall only examine the first mode of influence ; the 
latter will come under oiir consideration, when we speak 
of the lungs. 

Habitual motion is necessary to all the parts of the 
body alike, is a condition essential to the functions of the 
muscles, the glands, the vessels, and the membranes, &c. 
But this movement, whicli is partly derived from the 



196 PHYSIOLOGICAL RESEARCHES 

heart, is very different from that which is communicated 
by the blood to the brain. 

The latter organ receives an impulse by which the 
whole of its mass is visibly raised, an impulse, in the 
intermission of which the whole of its masï subsides. 
On the contrary, the interior movement, by which its 
practicles are affected, is scarcely marked at all : and this 
depends upon the smallncss and the delicacy of the vessels 
by which its substance is penetrated. 

The contrary o( this appearance is observed in the 
movement occasioned in the other organs by the influx 
of the blood inta them : we see them neither rise nor 
subside; there is nothing like a' general impulse made 
upon them, because, as I have said, such impulse is lost 
from the little resistance of the surrounding parts. On 
the contrary, they are penetrated by vessels of considéra-* 
ble Biagnitude, which create an intestine motion, oscilla- 
tions, and impulses adapted to the actions of the tubes^ 
lamellae, or fibres, of which they are composed. Tbia 
difference of movement may be easily conceived , by com- 
paring the manner in which the brain on the one hand, 
and on the other the liver, the spleen, the muselés, or 
the kidneys receive their blood ; indeed it is requisite 
that the brain should be distinguished from the other 
organs^ in the manner of receiving its impulses, because 
it is enclosed in a case of bone, and consequently abstract- 
ed from the thousand other causes of agitation, to which 
the other parts of the body are exposed. *. 

For we may remark, that all the other organs have 
about them a number of agents, which are destined to 
supply the place of that general impulse, which is want- 
ing to them on the part of the heart. In the breast, the 
intercostals and diaphragm are continually rising and 
falling ; the lungs and the heart are successively the seat 



ON LIFE AND DIIATH. 197 

of a- dilatation and contraction. In the abdomen , there 
is an uninterrupted agitation produced, by the influence 
of respiration upon its muscular parietes ; an incessantly 
variable state of the stomach, intestines and bladder. 
Lastly, from the various contractions of the muscles^ the 
limbs have a still more evident cause of movement. 

Nevertheless, it is probable that every one of the 
organs, as well as the brain, has a general though obscure 
movement impressed upon it, from the pulsation of the 
arteries ; and hence, perhaps, we have the reason, why 
the greater number of the viscera, receive the impulse 
of the red blood upoq their concave surfaces, as may be 
seen in the kidneys, the liver, the spleen, and the intes- 
4nes* By such disposition, the impulse of the heart is 
lest divided.^ 

From what has now been said, we may add another 
reason to that which we have before given, for establish- 
ing in what way the functions of the animal life are 
intermpted from cessation of action in the red-blooded 
heart We may now also begin to explain the same 
phenomenon in the organic life. The reasot^ of such 
interruption in both the lives is the saine. It, is as fol- 
lows : 

1st. In the case of death affecting the red-blooded 
heart ; the intestine movement, which proceeds from the 
manner in which the arteries are distributed widiin the 

* It should not be lost sight of, that all this discussion tarns uppn the 
application of a principle which is by no means proved ; viz. that the 
different organs, in order to exercise their functions, require to be 
agitated by a partial or general motion. We haye already made . it 
appear, that as it respects the brain, this jarring of the whole mass, to 
which Bichat attributes so much importance, appears to be a circum- 
stance purely accidental from the entrance of the arterial blood. The 
same may be said of the oscillatory motion produced in the other organs 
by the pulsation of the ultimate arterial rainl^catîons. 



198 PHYSIOLOGICAL RESEARCHES 

substance of all the organs, both of the one and the other 
life, is suspended ; hence there exists no farther cause of 
excitement for the organs : they must consequently die. — 
2dly. The causes of the more -extensiFe and general 
movements of the organs are abstracted ; for almost all 
these causes depend upon the brain. We respire and 
move, only while the brain is alive . but m the brain 
must be in a state of coliapsus, as soon as it ceases to 
receive the impulse of its blood, its influence must be 
evidently annihilated. 

Hence it follows, . that the heart exercises over the 
different organs two modes of influence ; the one direct 
and immediate, the other indirect, and made through the 
medium of the brain, so that the death of the organs in* 
consequence of the death of the heart, is idimediate or 
mediate. 

We have sometimes examples of partial death, analo- 
gous to this sort of general dbath. Thus, when the 
circulation is imp>eded in a limb, and the red blood no 
longer distributed to its parts, such parts become at first 
insensiëlç and paralytic, then gangrenous.L The opera- 
tion of aneurism furnishes us with too many instances of 
this phenomenon, which by ligature, maybe produced 
also in the living animal. Undoubtedly the principal 
cause of death in these cases, is the want of that stimulus 
which it is the business of the particles of the red blood 
to create, in contradistinction to those of the black blood, 
but the absence of the intestine movement in question, is 
by no means a less real cause of suci:^ death. 

As for the interruption of the nutritive process, it 
cannot be admitted as a cause of the symptoms ^vhich 
succeed after the obliteration of a large artery. ' The 
slow, the gradual, and insensible way, in which this 
function is performed^ does not accord with the sudden 



ON LIFE AND DEATH. t9» 

and instantaneous production of those symptoms, especr- 
ally as they affect the animal life ; for this is annihilated 
in the limb at the very instant when the blood ceases to 
flow into it, just in the same way as it is, when by the 
section of its nerves^ the influence of the brain is abstract- 
ed.* ^ • 

Besides the preceding causes, which, When the heart 
is dead, suspend in general the whole of the animal and 
organie functions ; there is another cause of death which 
especially affects the greater number of the latter, such 
as the processes of nutrition, exhalation, secretion, and 
therefore digestion, which is only performed by means of 
the secreted fluid. This cause of death to which I refer, 
consists in* the necessary stop which is put to these differ- 
ent functions, in consequence of their no longer receiving 
the materials upon which they are exercised. Neverthe- 
less, such term arrives by degrees only, because they 
.receive the materials on which they act, from the eapil- 
kry, and not from the general circulation. Now the 
capillary circulation, is only subject to the influence of 
the insensible contractile powers of the parts in which it 
is performed ; and is exercised independently of the heart, 
as may be seen in the greater number of reptiles, where 
the heart may be taken away, and the blood be notwith- 

* When the passage of the arterial blood to a muscle is stopped, a 
more or less complete numbness soon takes place ; and this effect is 
too sudden to be attributed to the want of nutrition ; and as certainly 
it is not owing to the want of agitation by the pulsations of the ^mall 
arteries ; for if, the artery is left free, and a ligature is applied upon 
the vein, the pulsations are increased rather than diminished and yet the 
numbness appears &p quick m before. 

When the muscle has been a long time without receiving blood, 
gangrene seizes upon it; and this can then be attributed, in great 
measure, to the want of nutrition. The diminution of the temperature,, 
which necessarily takes place in an organ in which the blood ii not 
lenewed, matt Mlio contribute to this disorganization. 



200 PHYSIOLOGICAL RESEARCHES 

sUndiog obsenred to oscillate for a long time aûemranb 
io the minuter vessels.* It is manifest, then, that what- 
ever quantity of blood is left in tiie capillary system at 
the period of the death of the heart, will for some time 
afterwards be sufficient to keep up the functions in ques- 
tion, and that such functions in consequence will only 
gradually cease. 

The following is a general view of the manner, in which 
the annihilation of all the functions succeeds to the inter- 
ruption of those of the heart. 

The anipial life is terminated-7-lst. Because the oigans 
of \yhich it is composed, are no longer excited without, 
by the movement of the neighbouring parts, nor witl^in^ 
by the blood. — 2dlyy Because the brain, from want of 
excitement, can no longer be a cause of excitement. 

The or^nic life is terminated — 1st, Because, as in the 
animal life, there is a want of external and internal excite- 
ment for its different viscera. — 2dly, Because there is a 
want of the materials on which its functions are particu- 
larly exercised.. 

There are a number of other considersitions, however, 
besides those which w^ have mentioned, which prove the 
reality of the excitement of the organs, from the move- 
ment communicated to them by the blood, as well as the 
reality of the cause, which we have asserted to be that of 
their d^th, when such excitement ceases. 

For, 1st. — The organs which are penetrated only by 
the serum of the blood, such as the hair, the nails^ the 
tendons, and cartilages, enjoy a less degree of vitality, 

* We know that the blood puthed into the arteries distends the 
parietei of the^e vessels, and brings into action their elasticity ; now» 
after the heart has ceased to act, the«e parietes, by cobtractiiis, can 
impart, for some instants, an oscillatory motion to the floid contained 
in their cavity. 



- ■-. *5ljp^ 



OJX LIFE AND DEATH. 201 

and a less energetic action , than those in which the blood 
is made to circulate, either immediately by the heart, or 
by the insensible contractile powers of the parts them- 
selves. 

2dly. — When the white organs are inflamed, they 
receive an augmentation of life, a superabundance of sen- 
sibility, which frequently put them on a level in many 
respect» with those organs, which in their natural state 
are endowed with the highest degrees of life and sensi- 
bility. 

3dly. — Those organs which habitually receive the influx 
of the red blood, when inflamed, exhibit, in every instance, 
a local exaltation of the phenomena of life. In the two 
preceding instances, it is true, indeed, that the change of 
vital powers, preôcdés in point of time, the change which 
is made in the circulation ; the organic sensibility of the 
part, -has been augmented before the blood is carried 
thither in greater quantity ; but afterwards it is the afflux 
of such incres^d quantity of blood, which keeps up the 
unnatural action which has been established. A deter- 
mined quantity of blood in the ordinary state of the part, 
is necessary to the maintenance of that state ; but when 
the part receives a double or triple increase of energy, 
its excitant also must be doubled or tripled ; for in the 
exercise of the vital powers, there are always three things 
to be remarked ; the power inherent in the organ ; the 
excitant which is foreign to it; and the excitement which 
is the product of the twoT . 

4thly* — It is doubtless, for this reason, that the organs 
to which the blood is habitually carried by. the arteries, 
enjoy a degree of life, proportionate to the quantity of 
fluid by which they are injected. Such phenomenon 
may be observed in the gUns penis, in the corpora cav- 
ernosa, in the nipple, in the skin of the face, and the 

26 



sot PHYSIOLOGICAL RESEARCHES 

aetions of the brain, whenever the blood is directed with 
impetuosity towards them. 

5thl7. — ^The whole of the circulatory system, is thrown 
into greater action from the exaltation of the whole of the 
vital phenomena, just in the same way as the particular 
circulation of any part is augmented, when the particular 
phenomena of the life of that part are increased. The 
use of spirituous liquors, and spices to a certain quantity, 
is followed for a time by a general increase of en^gy in 
the powers of the system. The access of inflammatory 
fever will double and triple the intensity of life. 

In these considerations I have only regarded the move- 
ment which is communicated to the organs by the blood; 
In ant>ther place I shall call the attention of the reader 
to that species of excitement, which is produced by the 
nature of the blood, by the contact of its . component 
particles when in a state of oxydation or otherwise, With 
the different parts of the body. The reflections which! 
have offered, will be amply sufficient to convince us how 
much the blood, independently of the materials which 
it conveys with it, by its simple influx, is necessary to 
the activity of the organs, and consequently how-much the 
cessation of the functions of the heart, must influence thç 
death of the orgatis. 



CHAPTER V. 

OF THE INFLT7ENCË OF THE DEATH OF THE HEART AS TO 
THE PRODUCTION OF GENERAL DEATH. 

Whenever the heart ceases to act, general death is 
produced in the following manner :-r*lst. For want of 



-Âfeâui 



OJi LfFE AND DEATH. <}03 

excitement the c^rebl^l actions are annihilated^ and con- 
sequently an end is immediately put to all sensation^ 
locomotion, and utterance. Besides, for want of excite- 
ment on the part of the blood, the organs of these func- 
tions would cease to act, even supposing that the brain 
were to remain unafiected, and exert upcPa them its accus- 
tomed influence. Thus the whole o£ the animal life is 
suddenly suspended, and at the instant of the death of the 
heart, the individual is dead to what surrounds him. 

The interruption of the organic life, which has com- 
menced by the death of the heart, is produced at the same 
time by that of the lungs. The brain being dead, the 
mechanical functions of the lungs must cease : the chemi- 
cal functions of the lungs must cease also, for want of 
the materials on which they are exerted : the latter are • 
directly interrupted, the former through the medium of 
the brain. 

After this the progress of death is gradual. The secre- 
tions, the exhalations, the nutritive actions are put an end 
to. The latter are first arrested in those organs which 
receive the more immediate impulse of the blood, because 
ih these, such impulse is necessary to the performance of 
the functions. The paler organs are less dependent on 
the influence of the heart, and consequently must be less 
afiected by the cessation of its action.'*^ 

In the successive termination of the latter phenomena 
of the internal life, the vital powers continuité subsist 
fbr some time after the loss of the functions : thus, the 
organic sensibility, and the sensible and insensible con- 

* Life Î8 90 obacnre in the tendons, ligament?, &o. that it is impossi- 
ble to fix the moment when it ceases in these parts. How then has 
Bichat been able to compare the quickness of their death with that of 
the other organs ? Upon what data has he been able to determine that, 
it takes place more slowly P 



104 rUYSIOLOGICAL RESEARCHES 

trftctilitias sarvive the phenomena of digestion, ^cretion, 
and nutrition.* 

The vital powers continue to subsist in the internal 
Kfe, even when the corresponding powers of the animal 
life, have suddenly become extinct : the reason is plain : 
the power of perceiving and moving organically does 
not suppose the existence of a comnfion centre ; for the 
animal perceptions and motions, the action of the brain 
is requisite. 

The phenpmena of death are concatenated in the above 
order in all aneurismal ruptures, in all wounds of the 
heart or larger vessels, in all cases of polypi formed in 
the cardiac cavities,! of ligature artificially applied, of 
compression exercised on the parietes of the heart by 
humours, abscesses, &c. &c. 

It is in this manner also that we die from sudden affec- 
tions of the mind. The news of a very joyful, or a very 
melancholy event, the sight of a fearful object, of a 
detested enemy, of a successful rival, are all o£ them 
causes capable of producing death. Now in all these 
instances, it is the heart, which is the first to die, the 
heart, whose death successively produces that of alt thV 
other organs, the heart, on which the passion is exerted. 

*The secretion of macns, the growth of the nails, the beard and 
the hair often continue on the dead body long after the last traces of 
irritability have disappeared in the muscles of locomotion, in the fleshy 
coats of the intestines, &c. 

t Since more care ^as been taken in examining the lesions ojf different 
organs in post mortem examinations, there is no longer found those 
fatty polypi, which were formerly considerec^as causes of death. U is 
probable that those yellowish concretions of albuminous matter which 
are found between the pillars of the auricle, and which seem to be fixed 
there, were mistaken for polypi. There is sometimes found in indi- 
yiduals formerly affected with the venereal disease, vegetations near tbe 
ralves ; but thest productions are commonly top trifling to oppose the 
expulsion of the blood contained in the cavity. 



ON LIFE Al^D DEATH. j^Ofi 

And hence we are led to some considerations on syn- 
cope, an affection exemplifying in a less degree the same 
phenomena, which in a greater one, is offered us in cases 
of sudden death. 

The causes of syncope are referred by CuUen to two 
general heads : Of these there is one set which according 
to him affect the brain, another set which affect the heart. 
Among the first, he places the more violent impulses on 
the mind, and various evacuations, but it is easy to prove, 
that the brain is only secondarily affected in syncope pro- 
duced by passion, and that it is the heart, whose functions 
in all these cases ai*e the first to be interrupted. The 
following considerations, if I am not mistaken, will leave 
but little doubt on this head. 

1st. — I have proved, in speaking of the passions, that 
they never affect the brain in the first place ; that the 
action of this organ, in consequence of their develop- 
ment, is only secondary, and that every thing relating to 
our moral affections has its seat exclusively in the organic 
life. 

2dly. — ^The phenomena of syncope when produced by 
lively emotion, are similar in every respect to those of 
syncope, the effect of pçlypi or dropsy of the pericardium, 
but in the latter, the affection of the heart is the primary 
one, and should in consequence be the same in the former 
sort of syncope. 

3dly. — At the moment when syncope takes place, we 
feel the attack at the heart, and not in the brain. 

4thly. — In consequence of lively passions, which may 
have occasioned syncope, we find that the heart and not 
the brain becomes* diseased, ilothing is more common than 
organic affections of the former from sorrow, &c. The 
different sorts of madness, which are produced by the 
same cause, for the mo^t part havo their principal seat in 



206 PHYSIOLOGICAL RESEARCHES 

some of the viscera of the epigastrium, and in sach case, 
the irregularity of the cerebral action is the sympathetic 
effect of the profound affection of the internal organ.* 

5thly.— I shall prove hereafter, that the cerebral system 
does not exert any direct influence over that of the circu- 
lation ; that there is no reciprocity between the two, and 
that the changes of the first are not followed by similar 
changes in the second, however much the changes of the 
second may modify tite first. Destroy all nervous com- 
munication between the brain and the heart, and the 
circulation will go on as usual ; but if the vascular com- 
munications be intercepted, the cerebral action vanishes 
at once. 

6thly. — Palpitations and other irregular movements of 
the heart are often the effect of the same causes^ which 

* The eiDg;Qlar idea of placing the seat of madnets in the viscera of 
the abdomen, arose at a penod when a certain number of mjitical 
ideas formed the basis of all physiology. The four sort» of humours 
performed in the human body (microcosm) a part as important as the 
four elements did in the whole universe (macrocosm.) The bile, the 
blood, the pituitary and atrabiliary fluids determined, by their predomi- 
nance the different temperaments, and produced the different diseases. 
The atrabiliary humour was, as is well known, thought to be the cause 
of melancholy and mania ; now this humour was said to be secreted 
by the supra-renal capsules, and the position of these organs no doubt 
gave the name of hypocondrie, which is given to a certain degree of 
mental alienation. 

After a great number of ages, the mysterious properties of numbers 
-are almost entirely out of favour. We still speak of the four tempera- 
ments, but attach no importance to the four ages of man or to the four 
parts of the day. We recognize in the human body more tbaa four 
kinds of fluids, but among them all we do not find the atrabiliaiy fluid. 
The cause of madness then cannot be attributed to this humour, and 
yet we dare not drive this disease from the seat it has so long held. In 
order to find reasons for keeping it there, they seek in the viscera for 
disorders which are not often found there even in the most striking 
cases, and which most often still exist wit^jont the least alteration hi tb« 
intellectual functions. 



. iAiiL 



ON LIFE AND DEATH. 207 

in some individuals are the occasion of syncope. In such 
cases, it is easy to discover the seat of the affection, and 
such smaller effects of the passions on the heart, are 
very well calculated to throw light upon the nature of the 
greater.* 

From these many considerations, we may conclude that 
Uie primitive seat of the attack in syncope, is the heart, 
which does not cease to act, because the action of the 
brain has been interrupted, but because it is the nature of 
some of the passions in such way to affect it, the brain 
at the same time, suffering a temporary death, because it 
no longer receives the fluid, which is necessary to its 
excitement. The nature of syncope is .well enough illus- 
trated, by the vulgar expression of being sick at heart. 

It is of no importance to our present purpose, whether 
syncope depend on polypi, on aneurism, or be the result 
of some violent emotion. The successive affection of the 
organs is always the same. They die for the moment in 
the same way, as they really perish when the heart is 
wounded,, or a ligature put upon the aorta. In the same 
manner also are those s(H*ts of syncope produced, which 
succeed after any great evacuation of blood, pus or water. 

* We «bould be often eiposed to commit great mistaken, if we always 
judged by this rale. Tbè sensation is a Terj uucertain meant of deter- 
mining the organ that is primarily affected ; this can be proved by 
numerous ezampl^s^ we shall pile one only which relates to. the brain. 
Nausea and vomiting are often, as is well known, among- the first 
symptoms of cerebral affections ; should we from this believe that the 
•eat of the disease is in the stomach ? Undoubtedly not : now, in 
syncope produced by a stroma affection of the mind, there is no reason 
to suppose that the heart is affected before the brain, since the intel- 
lectuiU phenomena have necessarily, preceded the sensation of joy or 
of sorrow which has produced the syncope. But to say that the brain 
was primarily affected, is not saying that its action ceased before that of 
the heart ; and every thin?, on the contrary, leads to the belief that the 
loss of the senses is a consequence of the suspension of the circulation. 



208 PHT8I0L0OICAL RESEAIICHE6 

The heart is affected from sympathy^ the brain for want 
of its excitant.* 

Those cases of syncope which are occasioned by pecu- 
liar odours, by antipathies, &c. appear also to be attended 
with the same proj^ression of symptoms, though their 
character be much less easily understood. There is a great 
difference between syncope, asphyxia, and apoplexy, in 
the first it is by the heart, in the second by the lungs, in 
the third by the brain that begins the general death of the 
body. 

Death, as it happens in consequence of disease, in gene- 
ral exemplifies a concatenation of these different' symp- 
toms. The circulation, respiration, or cerebral action 
cease, the other functions are afterwards interrupted of 
necessity, but in these sorts of death, it rarely happens 
that the heart is the first to die. This however is some- 
times the case. After long continued suffering, great 
suppuration, and sometimes, in dropsy, certain fevers, 
and gangrenes, one fit of syncope comes on after another, 

* The fjncope is produced in this case, from the sudden change in 
the circulation of the brain. But this change Taries according to the 
seat of the effusion. If it be in the peritoneal cavity, the pressure that 
it makes interrupts the circulation in all the organs contained in the 
abdomen ; the descending aorta is found compressed, and the blood, 
forced back towards the superior partt, accumulates in the sinuses 4àod 
vessels of the brain. If the fluid be evacuated by puncture^ the 
equilibrium is re-establislied in the different parts of the vascular sys- 
tem, the blood enters vessels which were before closed to it, it abandoni 
in part those of the brain, and it is this sudden change in the ciroola- 
tion of the organ which produces syncope. If, on the contrary, the 
effuflion be formed between the two layers of the arachnoïdes, and we 
can, a» in Fpina bifida, evacuate the fluid by puncture, the vessels of th« 
brain are immediately relieved of the pressure to which they had been 
subjected, and the blood, which before was forced back, towards the 
inferior parts, is driven forcibly into them ; the change is, as mast be 
perceived, the reverse of the preceding ; but the result is the same, and 
«vncopc is prodooed in this case as in the other. 









T* 
,» 



ON LIFE AND DEATH. 209 

at last a longer one succeeds, and the patient dies, but 
whatever be the part affected, whatever the diseased 
viscus or organ, whenever the phenomena of death com- 
mence by the heart, they succeed each other as we have 
described them to do in sudden death, from lesion of that 
organ. In other cases, the heart is the last to act, is the 
ultimum moriens. 

In general, in morbid affections, we much more com- 
monly observe the ingress of death to be made by the 
lungs, than either by the heart, or the brain. 

Whenever disease is terminated by syncope, the lungs 
are found to be almost empty, and if not affected by any 
organic disease, are collapsed, occupy a part only of the 
cavity of the thorax, and are of their natural colour. 

The reason of this anatomical fact is simple. The 
circulation which has been suddenly interrupted, has not 
had time to fill the vessels of the lungs, as happens when 
death begins, by affecting the lungs or the brain. The 
truth of this fact I can vouch for, having frequently 
ascertained it by dissection, and in general, as often as 
death commences by the heart, or the larger vessels, such 
vacuity of the lungs may be considered as universal. 

I have remarked it in the bodies of persons who have 
died from great hemorrhage from wounds or aneurismal 
rupture and violent passion, as well as in those who have 
suffered by the guillotine. The same phenomenon may 
be seen, by inspecting the lungs of any animal, which is 
killed in our butcheries. 

In killing the animal slowly by the lungs, that organ 
might be filled with blood. Its taste would then be dif- 
ferent from that which it naturally possesses, and resem- 
ble that of the spleen. Our cooks know well how to 
take advantage of that state of infiltration in which the 

latter viscus is generally found. 

27 



210 PHYSIOLOGICAL RESEARCHES 



CHAPTER VI. 

OF THE INFLUENCE OF THE DEATH OF THE LUNGS OVER 

THAT OF THE HEART. 

We have already said, that the functions of the lungs 
are of two kinds, mechanical and chemical. Now the 
activity of this organ ceases sometimes by the former, 
and sometimes by the latter of these functions. 

Any wound, which exposes the lungs on both sides^ 
for a considerable extent, occasions their sudden collapse; 
any division of the spinal marrow, which suddenly para- 
lyses the intercostals, and the diaphragm ; any very, 
strong compression exerted at the same time upon the 
whole of the thorax, and the parietes of the abdomen, 
any sudden injection of a large quantity of fluid into this 
cavity, are all of them causes wliich begin the death of 
the lungs, by putting an end to their mechanical functions. 
Those which influence in the first place their chemical 
functions, are the difierent sorts of asphyxia, strangula- 
tion, submersion, and a vacuum, in whatever manner 
produced. 

I. In what manner is the death of the heart occasioned 
hy the interruption of the mechanical functions of 
the lungs. 

The interruption of the functions of the heart, can 
only succeed in two ways to that of the mechanical func- 
tions of the lungs : 1st. Directly, because a mechanical 
impediment is put to the circulation of the blood, by a 
state of collapse in the lungs. 2dly. Indirectly, because 




ON LIFE AND DEATH. an 

in such state the lungs no longer receive the materials, 
upon which their chemical functions are exerted, and 
therefore cannot transmit them to the heart. 

Physiologists have all of them admitted the first mode 
of interruption, in the Pulmonary circulation. Reflected 
on themselves, the vessels of the lungs have not appeared 
to them, to he capable of transmitting the blood, on 
account of the numerous angles which they make. This 
idea they have borrowed from the phenomena of hydrau- 
lics, and it is their reason for the death which ensues, io 
consequence of a too long continued expiration. 

Notwithstanding all which, it has been proved by 
Goodwynf, that in such case there remains a sufficient 
quantity of air in the air vessels, for dilating them enough 
to allow of the mechanical passage of the blood ; he 
proves in consequence, that an unnatural permanence of 
the state, in which the lungs are placed from the act of 
expiration, does not affect the blood in the way, which is 
commonly believed. This is one step towards the truth, 
but we shall approach it much more nearly, and even 
attain it, should we be able to prove, not only that there 
remains a sufficiency of air in the lungs to permit the 
transmission of the blood, but that the very folds pro- 
duced in the vessels by a state of collapse in the organ 
are not a real impediment to its course. The following 
observations and experiments will assuredly determine 
this fact. 

1st. — I have already proved, that a state of fulness or 
emptiness in the stomach, and in all the hollow organs io 
general, produces no apparent change in the state of their 
circulation ; and that the blood in consequence, will 
traverse the vessels, when bent or doubled upon them- 
selves, as easily, as when they are distended in every 
direction. For what reason should a different effect be 



A 



212 PHY8IOLOOICAL RESEARCHES 

produced io the lungs, by the same disposition of the 
parts? 

2d\y. — There are different vessels in the ceconomy 
which we may alternately bend or extend at pleasure : 
such are those of the mesentery, when exposed by an 
incision into the abdomen of the animal. Now in this 
experiment, which has been already made to prove the 
influence of the tortuous direction of the arteries upon the 
mechanism of their pulsation, if one of the mesenteries 
be opened, and then either bent or extended, in either 
case the blood will be thrown out with the same degree 
of violence, and in equal times will be emitted in equal 
quantities. I have always obtained the same result in this 
experiment which I have many times repeated. From 
analogy we might expect the same from the vessels of 
the lungs ;* and from the following experiment it may be 
proved. 

* It is not because the vessels of the langi have become tortooQt that 
the blood flows throtuch them with difficulty, but because they are com- 
prtssed. It was needless for Goodwyn to seek for reasons to prove, 
that the flattening of the lungs does not ofler a mechanical obstacle to 
the course of the blood. If he had observed with attention' the phe- 
nomena of respiration, he would ha?e seen that thb contraction, if it 
does not completely interrupt the circulation of the blood in the lungs, 
at least modifies it in a very remarkable manner. When the lunp con- 
tract, not only the bronchial cells are flattened, but the pulmonary 
vessels are compressed, and tend to espel the blood contained in their 
ca?ity. This fluid flows back then on one part towards the right ven- 
tricle by the pulmonary artery, and on the other it accumulates in the 
pulmonary veins before entering the left auricle. Hence we ice that 
the Jet by the carotid artery must increase rather than lessen in the last 
moments. But if the compression continues, as the capacity of the rami- 
ficationa of the pulmonary artery is diminished as well aa that of tba 
veins of the same name, the quantity of blood which passes through the 
lungs is less, and the jet by the carotid necessarily decreases. The 
experiment related by Bichat is then entirely opposed to the opinios 
which he advances. 



' z 



<wdfl 



ON LIFE AND DEATH. j^l8 

ddly. — Take a dog, cut the treachea, and adapt the tube 
of an iujecting syringe to it, then make a vacuum in the 

It is not onlj by influencing the course of the blood in the system of 
pulmonary Tessel» that the alternate motion of the thorax modifies the 
circulatioD. If we lay bare the jugular ?eiu of a dog, we perceive that 
the blood does not mo?e in its cavity from the sole influence of the 
right auricle, but in an evident manoer from the influence of the motions 
of respiration also. 

At each time that the thorax is dilated in inspiration, the vein is 
quickly emptied, flattened and its parietes are sometimes brought 
exactly against each other ; it swells on the contrary and fills with blood 
when the thorax contracts. A similar phenomenon takes place in the 
venae cavae. In order to render it evident it is sufficient to introduce 
by the jugular vein into the venae cavx a sound of gum elastic ; we then 
see that the blood flows through the extremity of the sound only during 
the time of expiration. . A similar effect is observed if we introduce a 
sound into the crural vein and direct it toward» the abdomen. 

Haller and Lorry have paid much attention to this phenomenon, and 
have proposed an explanation of it which seems very satisfactory at 
first view, though it is really imperfect. When the thorax is dilated» 
say they, it draws the blood from the venae cavae, and, by degrees, that 
of the veins which are near it. The mechanism of this inspiration it 
very similar to that by which the air is drawn into the trachea. When 
tbe thorax contracts, on the contrary, the blood is crowded back in 
the venae cavae by .the pressure which is made on all the pectoral organs, 
vessels, heart and lungs, by the expiratory powers, and by degrees 
arrives at the veins which terminate in them. Hence the alternation 
of vacuity and fulness which the jugular veins exhibit. 

If we open an artery, and examine with attention the jet of blood, 
we see that it increases in expiration, and this is especially evident 
when the animal expires, strongly or makes an effort ; but as we cannot 
always produce these efforts -at will, or a great inspiration, we can in 
some measure imitate the phenomenon and produce the contraction of 
the lungs by compressing with the hands the sides' of the thorax ; we 
see then the jet of arterial blood increase or diminish, in proportion to 
the pressure that is made. If respiration produces this effect on the 
course of the blood in the arteries, it is natural to think that it can 
influence the course of the venous blood, not only by means of the veinty 
as Hhller and Lorry thought, but also by means of the arteries. For the 
purpose of satisfying myself, I made the following experiment. I tied 



214 l'UÏSIOLOGICAL RESEARCHLS 

lungs, and cut the carotid artery. It is evident, that 
according to the common belief, the circulation should 
be immediately suspended, in this experiment, since the 
pulmonary vessels from their ordinary state of distension, 



the jugular vein of a dog; tbe vessel became empty below the -ligature, 
aod swelled much above, as uniformly happent. I punctured slighllj 
with a lancet the distended portion, so as to make a yerj small opening. 
I obtained in this way a jet of blood, which the ordinary motions of 
respiration did not modify evidently, but which trebled or quadrupled 
in size if tbe animal made any considerable effort. 

It might be objected, that tlie effect of respiration was not trans- 
mitted by the arteries to the open vein, but by the veins wbicb were 
free, and wbicb would have iranaaiitted the blood of the vensc cavae, 
towards the tied rein, by meant of anastomoses. It is easy to remove this 
difficulty ; in fact» in the dog the internal jugular vein i&, as it were, but 
tbe appearance of a vein, and tbe circulation of tbe head and neck is 
perfonAed almost entirely by tbe external jugular veins, which are very 
large. By tying at the same time these two veins I was sure of prevent- 
ing, in a very great measnre, the reflux which has just been spoken of ; 
but so far from the double ligature diminishing the phenomenon before 
stated, the jet becomes on the contrary more strictly in relation with 
the motions of respiration, for it was evidently modified, even by com- 
mon respiration ; which, as we have seen, does not happen in the case 
of a single ligature. In order to render the thing more evident, I tried 
it on the crural vein ; this vein and all its branches being furnished with 
valves, which oppose a reflux, if this phenomenon of the increase of 
the jet appears during expiration, we might be sure that tbe impulse 
came from the arteries. This is what I have observed in fact in many 
experiments. The crural vein being tied and punctured helow tbe 
ligature, the jet which is formed increases evidently in powerful expira- 
tions, in the efforts and the mechanical compressions of tbe parietes 
of the thorax with tbe hands. 

We see by thi» and the preceding experiments, that we cannot adopt 
witboat modification tbe expression of Haller and Lorry relative to the 
swelliDip of the veins. This swelling takes place, not only, as they 
say, by the flowing back of the blood of the venae cavse into the 
branches which open into them mediately or immediately, bat also by 
the entrance into the vein of a greater quantity of blood coming from 
the arteries. 



ON LIFE AND DEATH. 215 

must baye paned to the greatest possible degree of col- 
lapse, in consequence of the total abstraction of air$ 
notwithstanding which the blood will be violently thrown 
out from the divided arteries for a certain time, and must 
consequently traverse the lungs : it will afterwards cease 
by degrees, but this, from causes which I shall explain 
hereafter. 

4thly. — The same effect may be produced by opening, 
on both sides, the breast of a living animal, because the 
warm and rarified air of the lungs, will be more than 
balanced by the pressure of the colder air without;* now, 

* As in dead bodies the air within and the air without are of the same 
temperature, the lungs, when they are full of it, do not flatten when the 
thoracic cavity is opened. There is usually then a space between thé 
parietes and the contained orçans ; this is not because we die in expira» 
tion ; foras the lungs empty theiuselves, the ribs and intercostal muscles 
rest upon them ; it is because the pulmonary air, in cooling occupies 
less space, and the cells contracting gradually as the cooling takes place, 
diminish the whole f'lzt of the organ. A vacuum is then made between 
the pectoral and pulmonary portions of the pleura. 

It is thus that, under some circumstances, the brain flattening and 
lessening after death, whilst the cavity df the cranium remains the same, 
a vacuum is formed between these two part?, which then exhibit an 
arrangement different from that of the living organs. If the sacs with- 
out an opening, as the peritoneum, tunica vaginalis, &c. never resemble, 
in this respect, the pleura and arachnoïdes ; if their different surfaces are 
always contiguous after death, it is because the abdominal parietes or 
the skin of the scrotum, unable to resist the external air, flatten by 
pressure, and are brought again»t the internal organs, as the diminution 
of these tends to form a vacuum. 

It is to this vacuum existing in the rleura of dead bodies, that roust 
be referred the following phenomenon, which is always observed when 
the abdomen b opened and the diaphragm dissected. In fact, as long 
as no opening is made in this muscle, it remains distended and concaiv, 
notwithstanding the weight of pectoral viscera which rest ii)M)n it in 
a perpendicular situation, because the external air, which presses the 
concavity of it, forces it then into the vacuum in the thorax, which 
never exists during life. But the instant the air is admitted by a cut of 



316 PHYSIOLOGICAL RESEARCHES 

neither in this case does the circulation experience any 
sudden change. For the sake of greater exactness, the 

the scalpel, thif muscular partition flattens, because the equilibrium 
is established. If all the air is drawn from the lungs bj a syringe, the 
diaphragmatic arch is still more evident. 

There is then this difference between the opening of a dead body and 
that of a living one, that in the first the lungs are already flattened, and 
in the second they flatten at the instant of opening. The contraction 
of the cells, from the condensation of the air by cooling, is an effect of 
the contractility of texture or from want of extension, which as we 
have said, continues in a degree with the organs after death. 

Besides, if the lungs flattened in the dead body the instant the thorax 
was opened, it would be owing to the pressure of the external air, a 
pressure which would expel through the trachea what was contained 
in these organs. Now if, to prevent the escape of air, yon close her« 
metically the canal by fixing a tube to it the stopper of which u tight, 
and the thorax is afterwards opened, the lungr stiU flatten ; the air had 
already gone out of them. Make, on the contrary, the sane experi* 
ment on a living animal, you will always prevent the flattening of these 
organs, by preventing the expulsion of the air. 

In this point of view Goodwyn has gone on a wrong principle in 
measuring in a dead body, the quantity of air remaining in the langs 
after each expiration. Besides, if you open bodies ever so little, you 
will hardly find two in which there is the same arrangement in the 
lungs. The infinitely various manner in which life terminates, by accu- 
mulating more or less blood in these organs, by retaining more or less 
air in them. Sic. gives them so variable a size, that no general data can 
be established respecting them. On the other hand, can we hope to 
be more successful on the living body f No ; for who does not Icnow 
that digestion, exercise, rest, the passions, tranquillity of mind, sleep^ 
watchfulness, temperament, sex, &c. make an infinite variety in the 
forces of the lungs, the rapidity with which the blood circulates through 
them, and the quantity of air that penetrates them ? All the calcula** 
tions on the quantity of this fluid which enters or goes out according to 
the inspiration or the expiration, appear to me to be physiological 
errours, inasmuch as they assimilate the nature of vital forces with that 
of physical forces. They are as useless to science as those which had 
formerly for their object the muscular force, the velocity of the bloo49 
&c. Besides, observe if their authors agree better among themselves 
then they used to do on this much agitated point. 



ON LIFE AND DEATH. 217 

little air remaining in the cells of the organ may be 
voided by a syringe. 

Along with these observations let us place the facility 
with which the pulmonary circulation continues to be 
made, when collections of water , pus, or blood , are lying 
within the pleura, or pericardium. In these cases the 
air vessels are often prodigiously contracted, and conse- 
quently the vessels of their parietes doubled and bent.* 
If this state be taken into consideration, we shall have 
sufficient data for concluding that the tortuous disposition 
of the vessels, can never be an obstacle to the passage of 
the blood ; and therefore, that the interruption of the 
mechanical functions of the lungs, can never directly put 
a stop to the action of the heart, though it niay do so 
indirectly, in impeding the exercise of the chemical 
functions of the lungs. 

If tKen we can determine why the heart remains 
inactive, when the latter phenomena are annihilated, we 
shall have resolved a double question. 

Many authors have asserted that the death, which 
ensues after a too long continued inspiration, is owing to 
the mechanical distension of the pulmonary vessels by 
the rarified air, a distension impeding the circulation. 

* ft 18 incoQceivable how Bichat could think of confirmiog his opinion 
by the example of hydrotborax. Who does not know that when an 
effusion takes -place in the cavity of one of the pleuras, that that portion 
of the lungs only which is' above the level x)f the water serves the 
purposes of respiration ; that when the effusion has arrived to the sum- 
mit of the cavity, the lungs of that side, which can no longer dilate, 
are of no use in respiration ; and those of the other, being compelled 
alone to make the necessary modifications in the blood, mn|t be 
traversed by the greatest part of this fluid ? It is known, finally, that 
in this case the patient cannot lie down an instant on the sound side, 
because this position prevents the dilatation of the lungs of that side 
which alone serve for respiration, and the danger of suffocation is 
therefore imminent. 

28 



ftl$ PUTSrOLOGICAL RESËARCIliLS 

But this reason also is as false a one, as that which we 
have already disproved. Inflate the lungs as powerfiilly 
as may be, then tie the trachea and open the carotids^vand 
the blood wiH flow as impetuously^ as when the respira- 
tion was perfectly free.* ^ 

IL fFAy does the heart cease to act, when the chemical 
functions qf the lungs are interrupted. 

According to Goodwyn, the reason why the contrac* 
tions of the heart are stopped, when the chemical func- 
tions of the lungs have ceased to be performed, consists 
in the want of that excitement which the red blood only 
can produce upon the red-blooded ventricle. This yen- 
triclci says he, has not a sufficient stimulus in the black 
bloody and death is occasioned because it no longer is 
capable of transmitting any thing to the difiereotr^irgans. 
In this case death must happen, as it would from ligature 
of the aorta — precisely in the same wsy as when its 
source is exclusively in the heart. The other parts dîe 
only for want of blood, just as when in a machine, the 
principal spring being taken away, the others cease to 
act, because they are not put into action. 

On the contrary, I am persuaded that there is a general 
afiection of all the parts, whenever the chemical functions 
of the lungs are suspended ; I am persuaded that the 
black blood continues to be pushed on for some time by 
the aorta, and that its influx into the organs is the occa- 
sion of their death ; • that the organs die in fact, not 
because they do not receive blood, but because they do 
not receive red blood; in a word, that they are penetrated 

* The observation of Bichat it very jiiat ; and I bave myself often 
observed in cases of apoplexy, that the motions of the heart contiaoe 
many hours after the arteries contain only black blood. 



ON LIFE AND DEATH. jglQ 

by the material cause of their death ; so much so, that 
we may asphyxiate any isolated part at will, by injecting 
it with venous blood while all the others shall continue 
to receive the red blood of the heart. At present I shall 
inquire into the phenomena of the contact of the black 
blood with the parietes of the ventricle, and refer the 
reader to the following chapters, for its effects upon the 
other parts. 

The movements of the heart may be stopped and made 
to cease altogether from the influence of the venous blood 
in two ways. — 1st. As Goodwyn has said, because the 
left ventricle is not excited by it upon its internal sur- 
face. — ^2dly. Because such fluid, when carried into the 
substance of the heart by ihe coronary vessels, must act 
upon the muscular fibre of the heart in the same way at 
it does upon the other muscles. Now, for my part, I am 
assured that the black as well as the red blood, will excite 
into contraction the internal surface of the aortic ventricle. 
The following observations and experiments will confirm 
my assertion. 

1st. If asphyxia were to be followed by the conse- 
quences which Goodwyn has supposed, it should influence 
the heart in the first place; the annihilation of the func- 
tions of the brain, as in syncope, should be only secon- 
dary ; nevertheless, asphyxiate an animal, by stopping up 
the trachea, by placing him in a vacuum, by opening the 
chest, or plunging him into carbonic acid gas, and it will 
in every instance be observed, that his animal life is the 
first to be interrupted, and that the creature externally is 
dead ; but that within the heart continues for some time 
afterwards to act^ and the pulse to be felt. 

In this way the symptoms of asphyxia are not the 
symptoms of syncope. In the latter the cardiac and 
cerebral actions are suspended at the same instant^ in the 



2jB0 PHYSIOLOGICAL RESEARCHES 

former the heart survives, as in cases of strong concus- 
sion of the brain for many seconds. It follows, that in 
asphyxia, the different organs do not cease to act, because 
the heart has ceased to supply them with blood, but 
because it no longer supplies them with that sort of blood 
by which they can be stimulated. 

2dly. If the trachea of an animal be stopped, and an 
artery opened, the colour of the blood which it emits, 
will gradually be changed, and at last become as black as 
that of venous blood. Now, notwithstanding this phe- 
nomenon, which is as apparent as it can be, the fluid for 
some time afterwards is thrown out full as strongly as it 
would be, were it red. I have seen à quantity of black 
blood discharged in this way, more than sufficient to kill 
the creature from haemorrhage ; were it not already dead, 
in consequence of its asphyxiated state. 

3dly. In the last-mentioned experiment, it may, indeed, 
be alleged, that some remains of air in the air cells, 
might, as long as the black blood continued to flow, have 
communicated to it a principle of excitement; but to put 
it out of all doubt, that the venous blood does really pftss 
into the aortic ventricle, unaltered in its passage from the 
corresponding cavity, the air may be entirely pumped out 
of the lungs with a syringe, by exposing the trachea, in 
the first place, and then adapting the instrument to the 
transverse section of the tube ; after this, let the carotid 
be opened ; now as soon as the red blood contained in 
this artery is exhausted, the black blood will succeed to 
it, and that, without undergoing a variety of gradations 
in colour ; in this case also for a time, the jet will be 
very powerful, and only be gradually weakened ; but if 
*the black blood were not an excitant to the heart, its 
interruption should be immediate. 



ON LIF£ AND DEATH. ^ 221 

4tbly. The following is another proof of the same 
nature. Expose the breast on one side by sawing exactly 
through the ribs before and behind : when this is done, 
the lungs oii that side will collapse. Proceed to open 
one of the pulmonary veins -, fill a, syringe warmed to the 
temperature of the human body with venous blood, then 
p«|sh it into the red-blooded ventricle. Now, according 
to the common opinion upon the subject of asphyxia, such 
fluid should at least diminish in a sensible way, the 
movement of that cavity, notwithstanding which, in four 
successive experiments, I could not, observe any such 
diminution. On the contrary, in one of them, on push- 
ing the piston, thç strokes of the heart were augmented 

in number. 

5thly. If the black blood be not an excitant to the 
heart, it can only want, such power, because it contains 
more carbon and hydrogen, than the red blood ;* but if 
the heart of an animal which has been killed expresslj 
for the expeiriment, by lesion of the brain or of the lungs, 
has ceased to beat, it may, notwithstanding, be made to 
contract as long as it preserves its irritability, by throw- 
ing into the aortic ventricle either hydrogen gas, or 
carbonic acid gas. It follows, that neither hydrogen gas 
nor carbon can act as sedatives tp the heart. 

The experiments which I made and published last year, 
on the emphysemata, produced in different animals with 
these gases, have established the same truth with respect 
to the muscles, since they do not cease to move in con- 
sequence of such experiments, and after death, preserve 
their irritability as they usually do. 

* At the period Biobat wrote, it was impossible to know whether the 
arterial or venous blood contained most hydrogen and carbon. At the 
present daj even, when the means of analysis are much more perfect 
«nd aninaJ chemistry Cirther advanced* we are hardly better informed. 



22» PHYSIOLOGICAL RESEARCHES 

LasUy. I have oftea succeeded in re-establishing tiie 
contractions of the heartj, which have been annihilated in 
different sorts of violent death, by the injection of black 
blood into the red-blooded cavities, with a syringe adapted 
to one of the pulmonary veins. 

Thus it is proved, that the red-blooded heart does 
actually push the black blood into all parts of the body ; 
and in this way is the colour given to the different sur- 
faces, of which, in one of the following chapters, I shall 
offer a sketch. 

Neither does the simple presence of the blaek blood 
act in a more sedative way upon the internal surfaces of 
the arteries.* If, in fact, while the tube adapted to the 
trachea is shut, the blood be made to flow from an artery of 
the foot, it will be thrown out for some time, with the same 
force which it would have been, were the pipe to be open. 
The action, then, which it exercises in its passage from 
the heart, upon the parietes of the arteries, does not 
diminish the energy of these parietes. When this energy 
decreases, it is at least in part from a different cause. 

From the above experiments we may conclude, that 
the black blood arriving in mass at the red-blooded ven- 
tricle, and correspondent arterial system is able, from its 
sole contact with them, to occasion the action of these 
cavities ; we may be equally certain, that were not the 
functions of these parts suppressed from other causes, the 
circulation would continue to be made in a very sensible 
manner, at least, if not with force. 

Of what nature, then, are the causes which interrupt 
the circulation in the heart and arteries when they are 

* It seems that wheD Bichat wrote this work,' he bftd not fiied in his 
own mind what part the arteries take in the circulation ; at least, in 
this paragraph, be seems to give them a contractile power, which, in 
his other worlu, be accords only, to their nltiiBate ranûficatioBs. 



f 



09 LIFE AND DEATH. 828 

supplied with yenOus blood ? Tor when this has been 
flowing for aome time, the jet of it is gradually weakened, 
and ceases at last entirely ; yet if the cock of the pipe be 
opened, it will be restored with vigour. 

I am persuaded that the black blood acts upon the heart 
as it does on all the other parts, as we shall see that it 
affects the brain — that it affects the voluntary muscles, 
the membranes, and the system in genera) ; the tissue of 
which it penetrates and operates within it as a débilitant 
upon each individual fibre. I am fully of opinion, that 
the circulation would be almost as quickly interrupted as 
in the preceding cases, were it even possible to supply 
the coronary arteries of the heart with red blood, while 
the black blood is transmitted to the various parts of the 
body by the aortic auricle and ventricle. . 

The black blood operates by its contact with the fleshy 
fibres, at the extremity of the arterial system and not by 
its contact with the internal surface of the heart. Thus 
it is only by little and little, and when each fibre has been 
as it were injected, that the powers of such fibres diminish 
and cease. On the contrary supposition, their cessation 
and diminution should be almost sudden. 

It may be demanded in what manner the black blood 
acts at the extremities of the arteries, upon the fibres of 
the different organs. Is it upon the fibres themselves, or 
upon the nerves which are distributed to them ? I am 
rather inclined to suppose the latter to be the fact, and to 
consider asphyxia as an effect produced in general by the 
black blood upon the nerves, which every where accomr 
pany the arteries of a certain diameter : for as we shall 
presently see, the debility which in such case the heart 
experiences^ is only a particular symptom of a disease 
in which the organs in general are the seat of a like 
debility. 



2U4 PHYSIOLOGICAL RESEARCHES 

It might be demanded' also in what way, that is to say, 
by what manner of influence, the black blood acts upoQ 
the nerves or fibres. Is it from the principles which it 
actually contains, or from the absence of those which are 
proper to the red blood ? Is oxygen the principle of 
irritability — are hydrogen and carbon the reversé? 

These questions have been sufficiently disputed. — ^Let 
us stop when we arrive at the limits of rigorous observa- 
tion. Now, I think, that we shall establish an assertion 
the most strictly conformable with sach principle, in say- 
ing generally and without determining the manner, that 
the heart ceases to act, when the chemical functions of the 
lungs are interrupted, because the black blood witb'wbich 
its fleshy fibres are penetrated, is not of a nature to keep 
up their action. 

From this manner of regarding the phenomena of 
asphyicia with relation to the heart, it is evident that 
both the ventricles should be equally afiected by it, be- 
cause their parietes must be equally injected with venous 
blood. Nevertheless, it is constantly observable, that 
the movement of the red-blooded heart is the first to 
stop ; that the black-blooded heart in every case the ulti- 
mum moriens ; but this phenomenon does net suppose a 
more real, a more decided debility in the one, than in the 
other heart ; for as Haller observes, the fact is common 
to every kind of death in the i*ed-blooded animal, and not 
the case particularly in asphyxia. — Besides, were the red- 
blooded heart the first to be absolutely afifected, as the 
theory of Goodwyn supposes, the following would be the 
appearances on opening the asphyxiated subject. — 1st. A 
distension of the corresponding auricle and ventricle, by 
the black blood which they would not be able to expel 
into the aorta. — 2dly. An equal fulness of the pulmo- 
nary veins and lungs. — 3dly. A consequent fulness and 



ON LIFE AND DEATH. 



9M 



swelling of the pulmonary artery and the black-blooded 
cavities. In a word, the congestion of the blood should 
be the greatest in that of its reservoirs^ whose action is 
the first to cease. 

But this is contrary to observation — for 1st. In the 
asphyxiated subject, the red-blooded cavities and pulmo- 
nary veins, contain but a very small quantity of blood in 
proportion to that which distends the opposite heart 
2dly. The place where the blood has stopped, is found 
to be principally in the lungs, in the lungs must we begia 
to follow its accumulation into the venous system. . Sdly. 
The arteries are as full of blood as their correspondent 
ventricles, and consequently it cannot be in the ventricle 
more than elsewhere, that death has been begun. 

But what is the reason why the black-blooded heart is 
the last to beat ? because, says Haller, it is the lon^st 
excited ; because it contains a greater quantity of blood ; 
because the blood is sent into it from the largest veins 
of the system, and regurgitates from the lungs. The 
famous experiment is well known by which in emptying 
the black-blooded cavities, and tying the aorta so as to 
retain the blood within the red-blooded cavities, the con- 
tractions of the latter are prolonged so much beyond the 
contractions of the former. . But in this experiment it is 
manifestly the black blood which accumulates in the aortic 
auricle and ventricle, because the breast must be prelimi- 
narily opened, and therefore the lungs collapse. 

Should a more direct proof beYequired, immediately 
before the experiment, let the trachea be closed with a 
syringe, and the air of the lungs be voided ; the experi- 
ment will just as well succeed ; besides, the operator to 
be sure of the colour of the blood in the aortic cavities, 
has nothing more to do than to open them, as soon as he 

has finished his experiment 

29 



ZM 



PHYSIOLOGICAL UESEARCHF.S 



We shall conclude that the black blood is almost as 
powerful a stimulus as the red blood to the inner surface 
of those cavities, which usually contain the latter only : 
the reason why they are the first to be arrested in their 
action, is, because they do not receive so large a quantity 
of blood as the others. 

Notwithstanding what I have said, I do not entirely 
reject the idea of the red-blooded ventricle being not 
excitable by the black blood. It may indeed be less 
excitable by this sort of blood, than by the other ; but I 
believe that the preceding considerations will reduce this 
difierence of excitement to a mere trifle. 

The following, however, is an experiipent where such 
difference would appear to be very manifest. If a stop 
cock be adapted to the trachea, and an artery opened, the 
blood will blacken, and continue for some time to be 
thrown out with its ordinary force, but at last the jet will 
gradually grow weaker. If, after this, the air be admit- 
ted, the blood will almost immediately become red and 
its jet be visibly augmented. In this case the sudden 
augmentation appears at first to depend upon the simple 
contact of the red fluid with the sides of the aortic ven- 
tricle, since it has not had the time to penetrate the tissue 
of the heart ; but let things be a little attentively ex- 
amined, and it will soon be seen that this impetuosity of 
impulse, depends on the movements of inspiration and 
expiration, to which the animal is obliged, on the admis- 
sion of air into the lungs. The heart excited at its 
exterior, and perhaps a little compressed by these move- 
ments, is the occasion of such phenomenon, and expek 
the blood with a force which is far beyond that which 
results from its habitual contractions. • • 

What I have here advanced is proved, by the manifest 
diminution of the jet, as soon as once the lungs have taken 



ON LIFE AND DEATH. S^fèl 

on their accustomed degree of action. Besides, the influ- 
ence of a series of full expirations may be manifested 
without dividing the trachea. Open the carotid and pre- 
cipitate the respiration of the animal by tormenting it 
(for pain will constantly have this effect) and the jet of 
blood will be visibly increased. The same augmentation 
may be artificially produced, by suddenly compressing 
the parietes of the thorax. These experiments succeed 
best on animals already weakened by the loss of a certain 
quantity of blood. 

In the ordinary state of health however, a series of 
strong expirations will not be found to quicken the pulse. 
Of this I cannot assign the reason. 

From what we have now said, it follows, that the 
experiment, in which^ on the opening of the cock of the 
syringe, the blood is thrown out with augmented force, 
is not so conclusive as might at first be imagined. I con- 
fess that it embarrassed me m'uch for many days, I hold 
then my former conclusions to be good. 

In the red and cold-blooded animals, the action of the 
lungs has not so immediate a connexion with that of the 
heart, as it has in the red and warm-blooded animals. 

I tied the lungs of two frogs at their basis, having 
previously exposed them, by incisions made laterally into 
the breast, the circulation however continued as usual for 
a considerable time. After this experiment, I have seen 
on opening the breast, the movements of the heart pre- 
cipitated, a circumstance depending no doubt upon its 
contact with the air. 

I shall finish this chapter by the examination of an 
important question, and inquire into the reason, why when 
the chemical functions of the lungs arc stopped, the pul- 
monary arteries, the black-blooded cavities of the heart, 
and in a word all the venous system, are found so much 



22S PHTSIOLOGICAL RESEARCHES 

more full of blood, than the aortic system. In such ca^te 
the circulation appears at first to be interrupted in the 
lungSi and then in the other parts, according to their 
proximity to the lungs. 

This phenomenon must have been observed by all 
who have opened the asphyxiated subject. It has been 
explain^ed by Hallor and others, from the tortuosity of 
the vessels ; but this opinion I have sufficiently refuted.* 

But before I proceed to assign a more real cause, I 
shall observe, that the lungs, (when the blood is first 
arrested, because it finds in them the first obstacle to its 
progress,) are found in a singularly various state, accord«« 
ing to the kind of death of which the individual has died. 
In sudden, in instantaneous death, neither the lungs, nor 
the black-blooded heart are very much distended. 

I have observed this fact, 1st. In the bodies of two 
persons who had hanged themselves and were brought 
into my amphitheatre. 2dly. On two subjects who had 
fallen into the fire, and were instantly sufibcated. Sdly. 
On dogs which I have suddenly drowned. 4thly. Upon 
guinea-pigs, which I have killed in a vacuum, or in difier- 
ent gases, or otherwise. 

On the contrary, arrest the phenomena of respiration 
in a gradual manner ; drown the animal by plunging him 
in water, and taking him out alternately, aspbyxiaà^ him 

■ 

* It if oertaio» whatever Bicbat may say coDcerning H^ that Dumerout 
angles ia the course of a blood 'Vessel, by increasJDg the friction, flittit 
retard the coarse of the fluid which runs throagh its cavity. We maj. 
in fact believe that it is one of the causes, which, in the flattening of 
the longs, embarrass the circulation ; this cause exerts its action princi- 
pally upon the last ramifications of the pulmonary artery which, by 
their interlacing, form the bronchial cells ; another more powerful caase, 
which acts equally on the divisions of the vein and the artery is, as we 
have aaid, the pressure made on the lungs by the flattenhif of the thorax, 
and the elevation of the diaphragm. 



ON LIFE AND DEATH. 229 

by placing him in a vessel of gas imperfectly closed, con- 
tinue as long as possible such state of pain and anguish, 
and the lungs will be found extremely full of blood. 

Between the extreme fulness, and the almost complete 
emptiness of the pulmonary vessels, there is a variety of 
degrees; now by the manner in which we kill the animal, 
we can determine any one of these degrees at will : It is 
in this way that we must explain that state of fulness in 
the lungs of such subjects, as are usually brought into 
our amphitheatres : in the greater number of cases, the 
attacks of death are slow and gradual. 

But whatever be the state of the lungs in the asphyxi- 
ated subject, the venous system is full of black blood, 
especially about the heart. In this respect, there is 
always a very wide difference between the veins and the 
arteries, and accordingly the blood must find in the lungs 
the principal obstacle to its circulation : such obstacle, as 
we have said, does not proceed from the tortuosity, and 
state of collapse in the pulmonary vessels ; its causes are 
relative, first to the blood, secondly, to thp lungs, thirdly 
to the heart 

The principal cause depending on the blood, consists 
in the great quantity of this fluid, which passes from the 
arteries into the veins. In fact we shall soon see, that 
the black blood when it circulates in the arteries, is not 
capable of furnishing the materials of secretion, exhala- 
tion, or nutrition, or if it be so, that it is not a stimulus 
to the organs which are the agents of these functions.* 

* See the article on the influence of the lungs on all the parts. I am 
compelled here to dedace consequences from principles which I shall 
pro?e hereafter; sach is in fact the connexion of questions which have 
the circulation for their object, that the solntion of one draws aa a 
necessary consequence that of all the others. It is a circle in which it 
is always neceuary to suppose something, Icavinp^ it to he proved after* 
wards. 



230 PHYSIOLOGICAL RESEARCHES 

It follows aa a necessary consequence, that the portion 
of fluid which is usually taken up from the arterial sys« 
tern by these different functions, flows on into the venous 
system, together with the portion which should naturally 
pass thither; hence there must be contained a greater 
quantity than usual in the veins ; and therefore a greater 
difficulty be experienced in its passage through the lungs. 
Practitioners in opening the bodies of aspbjrxiated per- 
sons, have always remarked the abundance of blood 
which is met with there. The fact has been particularly 
remarked by Portal, and I have always found it in my 
experiments. 

The causes of obstacle to the passage of the blood pro- 
ceeding from the lungs, are first the non-excitement of 
this organ by arterial blood. In asphyxia, the bronchial 
arteries are penetrated by the black blood as well as the 
rest. Hence its obscure and dusky colour in this case. 
This colour and its successive shades, may be easily 
remarked in the collapsed lung, when the chest is open- 
ed ; but in asphyxia, such blackness is principally owing 
to the colour of the blood, contained in the pulmonary 
veins. 

The black blood when circulating in the bronchial 
vessels, produces upon the lungs the same efiect which it 
does in the heart, by- penetrating the coronary arteries ; 
it weakens the different parts — impedes their action, and 
the capillary secretions which should be made there, from 
the tonic powers of the organ. 

The second cause of obstacle to the circulation, when 
the chemical functions of the lungs are interrupted, is 
the non-excitement of the organ by vital air. The first 
efiect of such air upon the mucous surfaces of the air- 
cells, is to stimulate them, and so to keep them up in a 



ON LIFE AND DEATH. 231 

sort of perpetual erethism.* In the same way are the 
powers of the stomach brought into action by the pre- 
sence of aliment there, and those of every reservoir of the 
body, by the influx of their accustomed fluids. Again, 
such excitement of the mucous surfaces by foreign sub- 
stances keeps up their tone. The privation of such 
excitement, therefore, must put a stop to their capillary 
secretions, which depend upon their tonic powers. 

The diflerent aeriform fluids which take the place of the 
atmospheric air in the diflerent sorts of asphyxia, appear 
to act very difierently upon the tonic powers, or the insen- 
sible organic contractility of the lungs. Some of these put 
a sudden stop to the circulation, others not. Compare 
the asphyxias produced b}^ nitrous or sulphurated hydro- 
gen gas, with those whteh may be occasioned by pure 
hydrogen, or carbonic acid gas, and the difierence will 
instantly be seen. This difierence indeed, as' well as 
the various other phenomena observable in the various 
asphyxiae, depends on causes which we have not men- 
tioned, but the afiection of the air-cells, is evidently one 
of them. 

Lastly, the third cause of stagnation of the blood in 
the venous vascular system, is that debility, which takes 
place in the ventricle and auricle of this system, when 
penetrated with venous blood : on the influx of the blood 
from the cava, they are consequently distended, and this 
is the case also with the cava itself, for the very same 
reason. The causes which are now assigned, are sufficient 
to shew why the black-blooded system, is gorged with 

* I cannot see what can have induced Bichaf to admit this erethism 
of the lungs, the use of which cannot be imagined. It is quite enough 
to suppose io the organs the existence of those concealed properties, 
when there is need of them to explain their functions. 



232 PHYSIOLOGICAL RESEARCHES 

fluids in asphyxiae.* The followiog considerations will 
shew why the red-blooded system contains a lesser quan- 
tity of fluid. 

1st — ^The obstacle commences in the lungs; therefore 
the aortic heart must receive a less quantity than usual : 
hence, as we have seen, proceeds the quicker cessation of 
the contractions of thb ventricle. 

2dly. — ^The natural strength of the arteries, though 
enfeebled by the influx of blood into their parietes, is 
much superior to that of the veins, which besides are 
subject to the same cause of debility.t Accordingly these 
vessels and the aortic ventricle, are capable of surmount- 
ing the resistance of the capillary vessels of the body in 
general, much more easily than the veins and the venoua 
ventricle, are of vanquishing the capillaries of the lungs, 

* Ai the blood flows in the yeins in a conlinaout motion, the disten- 
tion of these vessels does not take place in the direct motion of the 
blood, but in its retrograde motion. Everj time the fight anriole con- 
tracts, a portion of blood, instead of passing into the ventricle of the 
same side, is forced back into the superior and inferior vense cavse, and 
into the principal venous trunks which open into them. Bj this reflux 
of the blood, these veins are dilated, and have a pulsation which b 
easilj seen in the jugular in verj thin people. Thii pulsation has 
received the name of the venQut pulse. When it is very evident, it 
maj indicate an obstacle to tiie passage of the blood from the auricle 
to the right ventricle. 

Another reflux of the blood in the veins corresponds with the moment 
of expiration, and is perceptible even longer. Wt shall toon have to 
speak of it, in speaking of the movemenit of the brain. 

t The natural force of the arieriet is not dependent on life, and con- 
sequently cannot be enfeebled by the entrance of black blood. This 
force is nothing but elasticity, which indeed ceases to be in action as toon 
as death takes place, but which does not cease to exist till the texture 
itself is destroyed and disorganized. As this property is very conspicn- 
ous in the arteries, it it tuflicient to drive the blood from their cavity at 
the initant of death, whilst it is too feeble in the veins to expel thit 
fluid entirely. That it is, that we find blood in the veins only, after 






X 



t 



t. 



ON UFE ANP DEATH. 2SS 

3(]ly. — kl the general capillary system» there is only 
one cause of want of action, viz. the presence of black 
blood in it ; to this in the lungs there is added another 
cause, the want of that habitual excitement which this 
organ receives. on the part of the atmospheric air: accord- 
ingly in the lungs, there is a greater resistance offered to 
the influx of the blood, and with respect to the heart, a 
less capability of surmounting such resistance. In the 
other parts, -the contrary of all this is observed, a less 
resistance to the influx of the blood from the arteries into 
the veins on the one hand,, and on the other a greater 
capability of overcoming such resistance. 

4thly.-r-In the general capillary, system, which is con- 
tinued on from that of the arteries, if the circulation be 
embarrassed at first, in any organ in particular, it may 
still continue to go on in the other organs, more or less, 
in which case the blood regurgitates by these others into 
the veins. On the contrary, as all the capillary system, 
which is the continuation of the general venous system, 
is concentrated in the lungs, the venous circulation must 
be suppressed, whenever this organ loses its powers. 

The preceding considcratioi^s, if.I am not mi;5taken, 
explain why the vascular systems are so unequally full 
of blood after death», a circumstance, which is common to 
almost every disease, as well as the asphyxias. 

In the latter sort of death however, although the gene- 
ral capillary, system presents a less degree of resistance 
than is made by the capillary system of the lungs, never- 
theless such resistance arising from the influx of the black 
blood into the oi^ns in general is very manifest, and 
produces two remarkable phenomena. 

The first is a greater quantity than usual of black blood 
in the arteries, and therefore a greater difiSculty of inject- 
ing these vessels. Such blood is seldom coagulated. 

30 



*. 



234 PHYSIOLOGICAL RESEARCHES 

Indeed in all cases the venous blood is much less coagu- 
lable than arterial blood. This fiact is proved^ Ist, By 
the experiments of modern Chemists. 2dly, By the 
comparison of the blood of varices with that of aneurisms. 
3dly, By the inspection of that which usuaHy stagnates 
after death in the veins of the neighbourhood of the heart. 

The second circumstance, to which I have referred, is 
the general livid colour of the greater number of the suf' 
faces, with the fulness of divers parts, such as the face, the 
tongue and lips. These two phenomena indicate a stagna- 
tion of the blood at the extremities of the arteries, in the 
same way as they denote the same effect in the pulmonary 
vessels; here there is a much more evident repletion, 
because as I have said, the capillary system is there con- 
centrated within narrow limits. 

The reflux of the blood of the veins towards the 
extremities is the reason assigned by authors for the livid 
appearance of asphyxiated persons. There is little reality 
in this cause : in fact, this reflux-, which is very sensible 
in the trunks of the veins, diminishes continually towards 
their ramifications, where it is impeded and rendered 
impossible by the valves, besides which, the following 
experiment is an eyident proof, that we must attribute the 
Hvidity in question, to the impulse of the black blood 
from the aortic ventricle. 

1st. — Adapt a syringe with its stop-cock to the divided 
trachea. 2dly, Open the abdomen so as to distinguish 
the intestines and epiploon. 3dly, Shut the cock. At the 
end of two or three minutes, the red tint which animates 
the peritoneum, and which is borrowed by this mem- 
brane from the vessels, which creep underneath it, will be 
chan<;ed into a dull brown colour. This colour may be 
made to disappear arfd -re-appear at will, by opening or 
shutting the syringe. 



V 



ON L!FE AND DEATH. 235 

Here we cannot, as if the experiment were made upon 
#ther parts, suspect that a reflux is propogated from the 
right ventricle towards the venous extremities, since 
the mesenteric veins, together with the other branches of 
the vena portae, form a system apart, independent of the 
great black-blooded system, and having no communica- 
tion with the cavities of the heart which correspond with 
this system. 

But I shall touch again upon this subject. The above 
experiment is amply sufiScient to prove, that the livid ity 
of the surfaces of the èody is owing to arterial impulse. 

At present we are in a condition to explain how the 
lungs are more or less gorged with blood, more or less 
livid, and how the livid ispots upon the different parts 
of the body are more or less marked accordingly' as 
the asphyxia has been more or* less prolonged : for it is 
evident, that if before death, the black blood have gone 
round the two systems ten or twelve times, it will inject 
the extremities much, more than if it had made such cir- 
culatlorn only two or three times ; at each révolution, a 
greater or less quantity will \ie left in the extremities, 
for Want of action in the capillary vessels. 

In finishing this chapter I shall take occasion to observe, 
that the splçen is the only organ oi the economy suscepti- 
ble like the lungs of assuming a very great variety of 
volume. Scarcely is it ever found in the same state. It 
has been falsely supposed that there is a relation between 
the plenitude or vacuity of the stomach, and the inequali- 
ties of the spleen ; but this is not the case, as I have said 
elsewhere. Such inequalities'* during the life of the body 
do not exist, and supervene Only at the instant of death. 

It appears, to me, that they depend especially upon the 
state of the liver, the capillary vessels of which, are the 
continuations of all the branches of the vena portas as 



236 PHY&IOLOGICAL REdEARCUCS 

the capillaries of the luofça are thoae of the great Teoous 
•yatem. Thos, when the hepatic capillaries from any 
cause whatever are enfeebled, the spleen must swell and 
be filled with the blood, which cannot traverse the liver."* 
In such case, if I may so express myself, there is ai» 
isolated asphyxia of the abdominal vascular apparatus. 
The liver being to the spleen, what the lungs are to the 
black-blooded cavities in common asphyxia. The resis' 
tance is in the former, the stagnation in the latter. But 
this matter may be better understood hereafter. Ex- 
riments upon animals killed in difierent ways, would 
throw much light upon it, and these I purpose undertak- 
ing. By these means we may rigorously establish the 

* The utate of the spleen in the dead body maj become in come 
nieaiiure an index .of the state of the circnlation during the last moment! 
of life. The swellinfç of it shows alrooft always the embarrstaiBeDt of 
the circnlation ; and not only in an insvlated system, saoh as that of the 
vena porta, as Bichat considers it, bat in the whole pulmonary system. 

When any cau^e impedes the circnlation in the capillariea of the 
liing^, it necefl»arily produces a stagnation of the blood in the divisions 
of the pulruonary artery, and by degrees the disturbance is felt even in 
the two venae cavae, but especially in the inferior, in which the blood 
rif>f!s Rgainft its gravity. The blopd aoonmalates in the principal 
branches ; the veins of the liver and kidneys swell more or less ; as to 
tliese organs themselves, the firmness of their teitnre hardly allows 
them to be distended, so they do not increase sensibly in sise, or if this 
increase takes place, it is slow. It is not the same with the spleen ; the 
looseness of its timture will admit a great quantity of liquid, and its 
sise can thus be doubled oc trebled in a very short time. It becomes 
then a kind of reservoir, in which is accumulated the blood which 
cannot pass through the lungs. 

It may be objected to what we have just said, that oftentimes in 
phthisis the greatest portion of the longs has become incapable of 
allowing the blood to. pass, and that yet after death, the spleen b found 
in a natural state. But it should be recollected, that phthisical patients 
have, during the latter part of their lives, but very little blood, so that 
each portion sent by the right ventricle always finds a sufficient channel 
for it in the longs. 



ON LIFE AND DEATQ. 291 

analogy ezisUng between the stagnation of the blood in 
the different branche» of the vena porUe, and that which 
is observed in the general venous system, in consequence 
of various kind8t)f death.. With respect to the spleen and 
its system of veins, in ordinary asphyxia, I have never 
remarked in it any peculiarity. 



CHAPTER Vil. 

OF THE INFLUENCE OF THE DEATH OF THE LUNGS OTEE 

THAT OF THE BRAIN. 

We have just seen, that in asphyxia, the movements 
of the heart are paralyzed, because its fleshy fibres are 
penetrated with venous blood. This fact should indicate 
the same to be the case with reference to the action of the 
brain. It is indubitably proved by experiment 

Whatever be the manner in which the pulmonary 
functions are interrupted, it is always the interruption of 
the chemical changes, which troubles the functions of the 
brain.* What I have said upon this, point with respect 

*Id a preceding article, Bichat maintaiiis tbat the entrance of the 
arterial blood contribntes to support the action of the brain, principally 
bj the jar which it comnmnicatet to this organ. It is astonishing» after 
thif^ that he should attribute the suspension of the cerebral functions to 
the interruption of the chemical phenomena of respiration father this 
to that of the mechanical phenomena. lie rconld not however be 
ignorant, that it is to the last that must be referred the greatest of the 
fwo motions with which the brain is constantly agitated. 

These motions of the brain in relation with those of respiration have 
been for a long time observed. Schitling. has described them in a 
memoir inserted in the first volume of the Memoirs of Learned Foreigneis. 
He has shown that the brain rises in expiration, and flattens in inspica- 



23S PilYblOLOGICAL RESEARCHES 

to the hearty is exactly applicable to the cerebral mass : I 
shall not repeat it. It remains to shew by experimeot, 

tion. Ualler, Lamurc and horrj hare since him invesU|[ftted this motion, 
and they bave given an explanation of it, which is defectiye onlj 
because they have been içnorant of the influence of respiration on the 
acceleration of the course erf the blood in the arteries through the 
medium of the capillary yessels. 

At the time of a strong expiration, all the pectoral and abdominal 
organs are compressed, and the arterial blood is forced more especially 
into the branches of the ascending aorta. This blood goes then in 
greater abundance towards the head, and has a tendency to pass more 
quickly in the veins which carry it towards the heart ; which would 
take place immediately if the veins were free. But the pressure 
made on the pectoral organs, has also made the venous blood flow back 
in the vessels which contain it. Now, this blood has just met that 
which comes from the arteries ; the vessel is distended, and the course 
of the fluid is arrested in the veins ; from that the brain swells and rises 
up ; but as soon as expiration has ceased, the dilatation which takes place 
in the chest attracts, in some measure, the blood of the superior venae 
cavz ; the veins which enter it are soon emptied and the brain flattens 
down. 

In reflecting on the mechanism by which this movement of the brain 
is effected by the influence of respiration, we cannot perceive why the 
phenomenon should be limited to the organ contained within the 
cranium, and especially why the spinal marrow should not equally 
partake of it. The coniiuuity pf tiiis organ with the cerebrum and 
cerebellum, its situation iu a cavity which it does not entirely fill, the 
numerous arteries which it receives from the intercostal and vertebral 
arteries, the number and size of its veins destitute of valves aire so many 
circumstances which should favour the accumulation of the blood 
at the time of expiration, and consequently produce its swelling. For 
the purpose of seeing if my conjectures were well fonndcd. J hftve 
made some experiments ; I laid bare in a young rabbit the spinal marrow 
at about the eighth or ninth dorsal verterbra, I saw it perfectly whole 
and surrounded by its coverings. At first I perceived no motion, but 
soon the animal being much incommoded by the position in which Î 
kept him, made a deep inspiration, and then I saw distinctly the spinal 
fiarrow flatten, and a small vacuum between the dura mater and the 
osseoos parietes of the vertebral canal. In the following expiration, 



A 



ON LIFE AND DEATH. 239 

and the observation of diseases, that when the ehemical 
functions of the lun^s ai*e put a stop to, it is the black 
blood which interrupts the action of the brain and that of 
the nervous system. In the firsi place let ns examine our 
experiments. 

I first began by transfusing into the brain of an animal, 
the arterial blood of another; that this- essay might serve 
as a point of comparison for* others. Open one of the 
carotids of a d6g ; tie the extremity towards the brain, 
and fasten a tube to that which is next the heart; then 
open the carotid of another dog, tie the extremity of the 
vessel next the heart, and fix the other end of the tube 
into that which is next the brain; then let the assistant, 
wha meanwhile should have had his fingers upon the 
artery of the first dog underneath the tube, reniove his 
compression, and the carotid df the second dog will be 
seen .beating under the impulse of the blood injected from 
the heart of the first. This operation fatigues but- little 

the animal ^hich receives the blood, particularly if one 

* • ' ■ . . ' 

the spinal marrow resumed its original size..^ I was unable to see any 
thing more in this animal. 

1 laid bare in a dog of middle size, the spinal* marrow, a little a6ove 
the lumbar region ; I could not mistake there a very evident motion, 
in relation with respiration : a flattening during iu8piratron,^nd a swel- 
ling during expiration. The phenomeno/i was so marked^ .that the air 
entered the vertebral canal with a noise, whilst the animal inspired, and 
was forced out when the animal expelled ths air from his lungs. 

For the purpose of latisfying myself that this motion took place in the 
spinal marrow and not in the dura-mater, I cut this membrane in the 
irhole extent of the openipg made iti the vertebral caqal, and I was 
able easily to convince myself that the motion was from the swelling 
of the spinal marrow. 1 am not however certain that there is not a 
slight rising of the organ from the dilatation of the' large veins in the 
anterior part of the vertebral canal, but this dilatation cannot be con» 
siderable, on account of the fibrous layer which covers the posterior face 
of these veins. 



r. 



MO PHTSIOLOOICAL RESEARCHES 

of the veins be previously opened, to prevent too great a 
iulneM of the vessels. It will live very well afterwards. 
This experiment has been often repeated, and always 
with the same results. 

After this experiment, I opened the carotid, and the 
jugular vein of another dog, and after tying the extremity 
of the carotid next the heart, received the blood of the 
jugular into a warm syringe, and injected it into the 
brain. The creature appeared immediately to be agitated, 
breathed quickly, and >seemed to be in a state of suffoca- 
tion, similar to that of asphyxia. Its animal life. became 
entirely extinct ; the heart, however, continued to beat, 
and the circnlation to go on for half an hour afterwards ; 
at the end of which time the organic life was terminated 
also. 

This dog was of a middle size, and about six ounces of 
blood were injected with a gentle impulsé, for fear of that 
being attributed to the shock, Which ought to have been 
the result of the nature and composition of the • fluid. I 
repeated this experiment upon three dogs the same day, 
and afterwards at different times upon others ; the result 
was invariable, not only as to the asphyxia of the animal, 
but even as to the concominant appearances. 

It might be thought that out of its vessels, and exposed 
to the contact of the air, the blood might imbibe a per- 
nicious principle, or be deprived of that which is requisite 
for the maintenance of life/ It might be imagined, that 
to this cause was owing the sudden death of the dog, on 
the injection of the brain with venous blood. To shew 
that this was not the case, I made a small opening in the 
jugular of a dog, to which I adapted a nàodcrately warm 
syringe, and pumped the blood immediately from the 
vein. — It was afterwards thrown; into the carotid : the 
symptoms were the same as the preceding, but less mark- 






ON LIFE AND DEATH. 241 

ed, and the deatli of the creature induced more slowly. — 
It is probable, then, that the air when in contact with the 
living blood without its vessels may alter it a little, but 
the essential cause of death is still the same. 

Hence it appears that the black blood either is not an 
excitant capable of keeping up the cerebral action, or that 
it acts in a deleterious manner, upon the brain. The 
injection by the carotid of various other substances will 
produce analogous effects. 

I have killed animals in this way with ink, oil, wine, 
and water coloured with indigo. The greater number of 
the excrementitious fluids, such as urine, bile, the mucus 
of catarrhs, occasion death also by their simple presence 
on the brain. The serosity of the blood is fatal, but not 
as quickly so. Now it is certainly upon the substance of 
the brain, and not upon the internal surface of the arteries, 
that these different substances exert their influence. I 
have injected them all into the crural artery. In this 
way they are none of them mortal, but occasion always 
a torpor, amounting even to paralysis at, times.* 

* Active substances introduced into the veins can act on the organs 
in many ways at once. They have at first their peculiar action which is 
nearly uniform, whatever, may be tlie mode of administration ; but they 
produce aUo other effects resulting from their physical properties, and 
these last may vary according to the form in which they are introduced. 

The subftance' introduced into the circulation have necessarily to 
pass through a double system of capillary vessels, and must conse- 
qucntly be very greatly subdivided. Hence we see that a viscid fluid 
would be unable to enter the smallest vessels, and that by Remaining in 
those which can admit it, it will prevent the passage of the blood, and 
occasion a congestion either of the lungs or some other organ, accord- 
ing as it has been injected into a vein or an artery.' A substance like 
quicksilver, which without being viscid, exhibits great cohesion among 
its particles, will produce precisely the same effects. The globules 
will never divide below a certain size. The air itself, mixed in a fluid 
such as the blood, will form bubbles which will divide with more difi- 

31 



242 PHYSIOLOGICAL REsEAllCHES 

The black blood is dotibtle&s fatal to the brain, the brain 
becoming at once a tonic from its presence. In what way 

cuUj aj (hey become iinaller, and which can finallj stop io the eotrance 
of the capillaries, so as Io prevent a free pas&a:;e of blood in a part of 
these TeM«l<*. Boerhaave tliouglit that it was always thus, by opposing 
a mechanical obstacle to the capillary circulation of the lungs, that air 
injected into the Yeint produced the death of the animal. 

In un eiperiment in which I proposed to niy&elfto change the nature 
of the blood by a foreign fluid, I injected into the jugular vein, of a 
dog, an ounce of Olire oil, thinking that this substance would circulate 
without inconvenience with the blood ; but it was not so, and the 
animal died in a few minutes after the injection. 

In exaoiining the organs after death, I saw that the oil had closed the 
last ramifications of the pulmonary artery, and that it bad also stopped 
the circulation and respiration, by preventing the passage of the blood 
to the left side of the heart, by tlte pulmonary veins. An injection 
made with a thick solution of gum tragacanth produced precisely the 
same phenomena as the oil. 

An inert, impalpable powder, suspended in water, immediately pro- 
duces death, if injected into the jugular vein, because it shuts up the 
last divisions of the pulmonary artery. 

If the injected substances are not divided at first in the blood, so as 
to spread uniformly into the different branches, death does not take 
place so quickly, because a part of the sanguineous canals remains 
free for the circulation. This is the case when we inject quicksilver 
or air in so small a quantity as not to produce instantaneous death. 
The congestion, in this last case, is often alone sufficient to produce it 
after a certain time ; in the other case, there is added to the obstruction 
a real pneumonia caused by the presence of quicksilver in thé obliterat- 
ed vessels. We shall now relate four experiments of M. Gaspard, which 
will show the efifects of the stagnation of ihi» fluid in different organs. 

'^ Firât Exptrimtnt. I introduced into the jugular vein of a small 
dog, four days old, thirty six grains of quicksilver purified through goaOs 
skin. Soon after he refused to suck, lost bis vivacity» motility and beat, 
had dyspnoea and fever, and died at the end of twcoW foor honrs, 
having been all the time moch colder to the touch than tb# «ther pups 
with whom be was. On opening the thorax, the lungs were found much 
inflamed, almost hepatized, heavy, puckered up and full of mercury.^* 

'^ Second Experiment, I injected into the left carotid arterj of a 
sheep, very near the brain^ half an ounce of mercury with water ; I 



ON LIFE AND DEATH. 4J43 

does it act ? I do not pretend to determine the manner ; 
for this were only to begin a series of conjecturos. 

then tied with a double ligature the open vessel. The animal immcdi- 
atçlj manifested pain, and was for an itistant immoTeable, the head 
inclined, with stupor and a prominence of the eyes, which were extra- 
ordinarily open ; then bending on the fore legs, twisting of the head 
and neck on the right shoulder, with a kind of stiffness or convulsive 
elasticity, which was always present till death, and returned, as by 
the effect of a springs when I straightened the lieck. TVo hours 
after, standing impossible, state of drowsiness, soote convulsive motions 
of the limbs, the left eye swelled, red and inflamed. The next day, 
the same state, almost total annihilation of the animal or external life, 
copious excretion of mucus by the left nostril, the eye still very large 
and inflamed. The third day, the same state ; death took place fifty 
hours after the injection. On examination of the body it was found 
that the left eye was in a state of suppuration and contained mercury ; 
the thyroid, pharyngeal auricular, lingual, hibial, nasal and cerebral 
arteries of the left side, were admirably injected with this* metal which 
run out under the instrument ; but their capillary terminations con- 
tained none of it, and we could see to what ramification, to what 
sized caliber it had penetrated, and the point where it was unable to 
pass ; the left nasal cavities exhibited a very pretty reticulated appear- 
ance, brilliant and silvery. Moreover all the organs of this side were 
red, inflamed and swelled by the presence of the foreign body-, and 
it was curious to see the half of the thyroid gland, the tongue, the 
cheeks and the lips thus red and inflamed to the median line, whilst 
the other half was sound and pale ; the left brain was slightly inflamed 
and especially the plexus choroides. Besides, 1 was unable to dis- 
cover a globule of quicksilver in any of the other organ?.^^ 

" 7%ird Experimeni, I forced with a pewter syringe into the crural 
artery of a large dog, a drachm and a half of quicksilver mixed with 
common water. The animal, immediately after the double ligature, did 
not manifest any sign of pain» and walked, bearing less on that limb, 
which was very seAsibly cold, though not paralyzed. But, about an 
hour after, he refused food, manifested by piercing cries acute pain, 
constant agitation, frequent change of place, and a very evident state 
of suffering ; the limb soon ofter grew warm, became hot to the touch, 
with an obscure pulse under the tendo Achiliis. This state of fever and 
pain continued the whole day and night. Thenext day, the limb was 
swollen aqd exhibited a phlegmonous œdema preserying the impres- 



244 PHYSIOLOGICAL RFIUSEARCHES 

By this time we are authorised to conclude^ that in 
asphyxis, the circulattoD which continues for some time 

fion of the finger ; the plaotive criei were continua]. On the third 
day his condition was still worfe, and I then killed him from com- 
passion sixty hours after the injection. 1 had carefully noticed the 
matter of the excretions, without discoTering a particle of quicksilver 
in them. On examination of the body, 1 could not discover it in any 
organ, except the limb subjected to the experiment, which was swollen, 
inflamed and oedematous in all its textures ; we observed abscesses 
in it of different sizes, containing quicksilver, pus, sanies and much gas, 
coming from the incipient gangrene of the parts ; the metal usually 
occupied the centre of all the abscesses ; the mercurial globules flowed 
out when I cut the skin, tàe cellular texture, the muscles and especially 
the small arteries, which were admirably injected by it ; gelatinous 
exudations occupied the interstices of the muscles.^' 

^^Fourlh Experimtnt. I injected a drachm of quicksilver, that had 
been passed through goat^s skin, info the mesentric vein of a dog of 
middle size. The animal exhibited several severe symptemi which I 
shall not mention, because they probably depended on the opening of 
the abdomen and the inflammation that resulted from it % perceiving 
that they would become fatal, I killed him by . another experiment, 
fifty two hours after the first. On opening the body, 1 foand all the 
mercury in the liver ; each globule was the centre of a small collection 
of pus, of which it was the cau«e; but the liver was but slightly dis- 
eased, but little inflamed, and only blacker and more gorged with blood 
than usual. The stomach contained an unusual quantity of very green 
bile ; I could not discover any quicksilver in the other organs.'' 

We see from all these différent fact!>, that it is necessary for every 
thing that enters the circulation to arrive at it by very narrow channels, 
and after having been, as it were, sifted by the agents of absorption ; 
thifl is one use of the absorbent organs that has not as yet been noticed. 
These facts also throw light on the properties of substances injected 
into the veins of animals, after having been dissolved in oil. We can 
believe that when these oily solutions are carried into the intestinal 
canal, they are not absorbed till after they have been gradually changed 
into a kind of emulsion, and we know that in this form fatty substances 
may be introduced with impunity into the circulation. We can in fact 
inject into the veins a large quantity of milk, and the portion of batter 
which is suspended in it, will not produce the effects which would 
neceisarily result from it, if we injected this substance pare and only 
readered liquid by heat. 



ON UFE AND DEATH. $45 

after the interruption of the chemical functions of the 
lungSy interrupts the cerebral functions, from its being 
composed of black blood only. The fact is proved in 
another manner, for the movements of the brain continue 
to be made as usual* 

If the cerebral mass be exposed, and the creature 
asphyxiated, the animal life will be extinguished, but the 
motion of the brain will be apparent still. Since then the 
latter cause of life subsists, the cause of death must be in 
the nature of the fluid, by which the organ is penetrated. 

Nevertheless, if any afiection of the brain coincide with 
asphyxia, the death which is occasioned by the latter^ 
will be quicker than is usually the case. Strike a dog a 
violent blow upon the head, and then if he be deprived of 
air, he will die on the instant In asphyxiating another 
animal already in a state of stupor, from compression of 
the brain, I observed that the vital functions were inter- 
rupted somewhat sooner, than when the brain is untouched 
during that operation ; but the consequences hitherto 
deduced, may be supported by other experiments. 

If in asphyxia the black blood suspend the action of the 
cerebral mass, it is evident that the black blood taken 
from the arteries of an animal dying of asphyxia, and 
injected into the brain of anotlier, will be the cause of 
death. 

The experiment will be found to succeed — cut the 
trachea, of a dog, and tie it up hermetically ; then in the 
course of two or three minutes, open the carotid and 
receive into a syringe the blood, which flows from the 
vessels ; inject it into the brain of another animal, and it 
will die. 

The following experiment is very similar, but oflers a 
somewhat difierent result. 1st. Adapt a tube with a stop- 
cock to the trachea of a dog, and a tube of silver to the 



24^^ PHYSIOLOGICAL RESKARCIlES 

carotid, next the head, after dividing this vessel, and tic 
up iho cxlrcmity towards the heart. 2dly. Fix the other 
end of the tube to the divided carotid of another dog next 
the heart, and tic the extremity of the vessel towc^rds 
the head. 3d1y. Shut the cock of the tube in the trachea, 
and the black blood of the one dog in a short time, will 
be injected into the brain of the other. 

The appearances above described will shortly after- 
wards succeed, but not so soon as in the former experi- 
ment, and if the transfusion be stopped, the animal which 
has been asphyxiated in this way, may recover and live. 
In the preceding experiment he will always die. It 
appears then that some extraneous pernicious principle is 
imbibed by the venous blood, when in contact with the 
air. Observe that for the latter experiment the dog from 
which the brain of the other is to be injected, must be 
stronger and more vigorous than the other. The reasons 
are evident. 

I was desirous of trying whether the venous blood 
would not be capable of keeping up the cerebral action, 
if reddened artificially. For this purpose I opened the 
jugular and the carotid of a dog, and received the blood 
of the vein in a vessel filled with oxygen; it immediately 
became of a vivid purple, but on its injection into the 
brain, the animal was very suddenly killed. I was much 
surprised at this result, but ceased to be so on remarking, 
that a great quantity of air was mixed with the fluid, 
and that it arrived upon the brain, in a state of foam : 
now we know that a very small number of bubbles are 
sufficient to kill an animal, whether they be introduced 
on the side of the brain, or on that of the heart. 

From this reflection, I was induced to repeat my expe- 
riments upon the injection of black blood, suspecting as 
I did that some small quantity of air might in these cases 



ON LIFE AND DEATH. «^47 

have been contained in the extremity of my syringe. I 
soon however recollected that if this cause were real, it 
should produce the same effect in every instance whatever 
were the fluid employed, now when water is injected 
there is nothing of the kind observable. 

We may be thus assured that the black blood is either 
incapable of keeping up the action of the brain, or that 
it acts in a deleterious manner upon that organ, from the 
very nature of the principles, which it contains. From 
such datum it should appear that the life of the asphyxi- 
ated person might be restored, by pushing on into the 
brain a sufficient quantity of arterial blood, but here we 
must make a distinction of two periods in asphyxia: 1st. 
That in which the cerebral functions are only suspended : 
2dly. That in which the circulation and the movements 
of the breast are stopped (for this disease is ever charac- 
terised by the sudden loss of all animal life, and con- 
secutively by that of the organic life.) JSow, as long as 
the first period of asphyxia continues, I have observed 
that, by the transfusion of red blood into the brain, from 
the heart of another animal, the movement of the crea- 
ture which is dying will be restored by degrees, and the 
cerebral functions resume in part their activity ; but this 
is only a temporary thing, and the animal will fall again 
into its previous dying state, if the asphyxiating cause be 
continued 

On the other hand, if during the first period, to which 
we have alluded^ the air be readmitted, into the trachea, 
the lungs will be reanimated, the blood be coloured, and 
the creature be revived without the assistance of any 
transfusion ; and such transfusion again is of no avail, 
after the second period of asphyxia, so that this experi- 
ment offers only a proof of what we already know; with 
respect to the difference of the influence of arterial and 



248 PHYSIOLOGICAL RESEARCHES 

venous blood upon the brain, and not a remedy in case 
of asphyxia. 

Again, whenever I have injected venous blood into 
the brain, by the help of a syringe, I have universally 
found that such proceeding is fatal. Though the cause of 
asphyxia be removed, and arterial blood injected, either 
with the syringe^or immediately from the heart of another 
animal, it is of little effect, and frequently of none what- 
ever. And in general asphyxia when produced by blood, 
which has been taken from the venons system itself and 
pushed into the brain is much more certain and more 
decided, than that which is occasioned by ligature of the 
trachea, or the introduction of different gases into the 
lunss. 

After having established by different experiments, how 
fatal the influence of the black blood is upon the brain, 
which receives it from the arteries whenever the chemical 
functions of the lungs are suspended, it will not be amiss 
or out of place to shew, that the phenomena of the 
asphyxia, which are observed in the human subject, 
accord with the experiments of which I have given the 
detail. 

1st. It is generally known that every kind of asphyxia 
affects the brain in the first instance ; that the functions 
of this organ are the first to be annihikted ; that the 
animal life, and particularly the sensations cease; that all 
our relations with exterior objects are instantly suspend- 
ed, and that the organic functions are only consecutively 
interrupted. Whatever be the mode of asphyxia, by 
submersion, strangulation, gases, or a vacuum, the same 
phenomena occur at all times. 

2dly. It is known that the greater number of those 
who have escaped suffocation, have been sensible only of 
a general stupor, the scat of which has been evidently in 



ON LIFE AND DEATH. t4$ 

the brain. It is known also, that death is almost always 
certain tn these cases^ while the pulse and the heart have 
ceased to be felt. 

3dly. It is affirmed by almost all such persons as have 
survived this accident, especially when caused by the 
vapour of charcoal, that the first thing of which they 
were sensible, was more or les» pain in the head, an effect 
in all probability occasioned by the first influx of the 
black blood into the brain. This fact has been noted by 
thç greater number of authors, who have written on 
asphyxia. 

4thly. The vulgar expression that ^'charcoal flies to 
the head'' is surely a proof that the brain, and not the 
heart, is the first affected in the asphyxia occasioned by 
this deleterious substance. Thé unprejudiced vulgar, 
oftentimes observe more correctly than we do, who fre- 
quently see only what we wish to see.* 

5thly. There are many examples of persons, who after 
escaping the pernicious effects of the vapour of charcoal, 
have been subject afterwards to paralytic affections, and 
loss of memory. Such changes have evidently their seat 
in the brain. Convulsion also is frequently the effect of 
the impression of mephitic vapour : head-ache is a com- 
mon symptom, and for the most part remains after the 
others have disappeared. In every book of cases may 
be seen examples of these affections. 

In cold-blooded animals, and in reptiles especially, this 
influence of the black blood on the brain, though real, is 

* U it true that common people observe without prejudice ? Ha?e 
they notf on the confrar}-, on several physiological and pathological 
phenomena deeply rooted prejudices ? It is besides a very singular 
idea to wish to judge by the name which they give to an affection, of 
the organ primarily affected. If we always reasoned in this way the 
expresflioD'of iiek at heart which it given to nausea, would assign to 
vomiting a wholly different nature from what would be oorr«ot> 

32 



25a PHYSIOLOGICAL RESEARCHES 

much less apparent. Alakc an incision into both sides 
of the breast of a frog, then tie the lungs at th0ir root^ 
and the animal will ]i^e notwithstanding for a consid- 
erable time. Cut away the lungs entirely, and the same 
phenomenon will be remarked. In fish, the relation 
between, the lungs and the brain, is somewhat more 
direct, for by the organization of the branchiae, they 
differ essentially from reptiles. I have taken away the 
cartilaginous plate which covers the gills of the carp, 
the motion of the gills however continued to be made as 
before, and the animal lived without any apparent injury 
done to its functions. I afterwards, put a ligature about 
the cartilaginous rings which sustain the branchise, so as 
to hinder all motion in the pulmonary apparatus. The 
effect was, that the animal languished, his fins dropt^ 
his muscular movements soon grew weak, then ceased 
entirely, and the creature in the course of a quarter of an 
hour was dead. The same phenomena with some little 
variety, were observable in a carp from which I cut away 
the branchiae. 

. After all however, the particular nature of those rela- 
tions, which unite the heart, the lungs, and the brain, 
both in the red and cold-blooded animals, is well worthy 
the farther investigation of physiologists. The latter sort 
of animals, can neither be subject to syncope or apo- 
plexy, or at least the character of these diseases must be 
very much modified in them. They are with much more 
difficulty asphyxiated. We shall now return to those 
species which bear a nearer resemblance to man. 

From the influence of the black blood over the heart, 
the brain, and the rest of the organs, it was my opin- 
ion,- that persons affected with varicose aneurisms, would 
perish less quickly from asphyxia then others; because 
the red blood passes into the veins^ and traverses the lungs 



ON LITE AND DEATH. 251 

without reqtiiring alteration. Accordingly, it should be 
capable of keeping up the cerebral action. 

To be assured if this suspicion were well founded^, I 
made a communication between the carotid artery and 
jugular vein of a dog> by nieans of a curved tube. The 
pulsation of the artery was thus communicated to the 
vein. I afterwards asphyxiated the animal by stopping 
the trachea, but the phenomena of death were little dif- 
ferent from those of common asphyxia. ' ^ 

We may conclude with certainty, from the various 
considerations and experiments presented in the present 
chapter. 

1st. That when the chemical phenomena of the lungs 
are interrupted, the black blood acts upon the brain, as it 
does upon the heart, by penetrating the tissue of that 
organ, and depriving it of the exftitement, which is neces- 
sary to its action. 

2dly. That its influence is much more rapid upon the 
first, than on the second of these organs. 

3dly. That it is the inequality erf such influence, which 
occasions the difference in the cessation- of the two lives 
in the case of asphyxia. The. animal life is always anni- 
hilated before the organic life. 

We may conceive from what has been said in this and 
the preceding chapter, how unfounded are the suspicions 
of those who have supposed that the brain, after the sepa- 
ration of the head from the body by the guillotine, might 
live awhile and have sensation. The action of this orgaQ 
is immediately connected with its double excitements. — 
1st, By motion; 2dly, By the nature of the blood which 
it receives. Naw, when the interruption of such excite- 
ment is sudden, the interruption of every kind of feeling 
must also be sudden. 



252 PHYSIOLOGICAL RESEARCHED; 

When the chemical functions of the lungs are suspend- 
edy the disturbance induced in thç functions of the brain, 
has indeed a. very considerable influence on the death of 
the other organs ; nevertheless, such disturbance, is Xhe 
beginning of death only in the animal life, and even then 
is connected with other causes. The organic life ceases 
from the sole presence of the black blood among the dif- 
ferent organs. The death of the brain is only an isolated 
and partial phenomenon of asphyxia, which does not take 
place in any particular organ, but in all alike. We shall' 
explain this assertion in the following chapter» 



CHAPTER VIII. 

OF THE INFLUENCE OF THE DEATH OF THE LUNOS. OVJÇB 
THAT OF THE ORGANS IN GENERAL. 

I HAVE just shewn in what way the interruption of the 
chemical phenomena which take place in the lungs, anni- 
hilates the functions of the heart and brain. It remains 
me to shew, that the other organs of the body are as much 
aflected by such cessation ; so that asphyxia, as I have 
said, is a general disease, and not an affection of any one 
organ in particular. 

But before I proceed to analyze the effects of asphyxia 
upon the organs in general, and consequently the mode of 
action of the black blood upon them, it may be of use to 
explain the phenomena of the production of this ^ind of 
blood, at the instant when the functions of the lungs are 
suspended. This paragraph will possess, perhaps, some 
interest; it might have belonged indifferently to either of 
the preceding chapters. 



ON LIFE AND DEATH. £53 



I. Exposiiion of the phenomena of the .production of 
black bloody when the chemical functions of the lungs 
are suspended. 

It is known in general, that the blood is coloured in 
traversing the lungs, that from black it beconiies. red ; but 
this very interesting fact, has not been hitherto-the object 
of any precise or rigorous experiment. The lungs of the 
frog, of which the air vessels' are large, and the mem- 
branes thin and transparent, would serve very well for 
the purpose of observing the process of the phenomenon 
in question, but for the slowness of respira tioa in these 
animals, the difiference of organization in their lungs, and 
the too small quantity of blood by which they are travers- 
ed. On such account there can be little analogy between 
them^ and the more perfect animals, and then again our 
experiments upon these little amphibiae, are all of them 
rendered incomplete, by the tenuity of their pulmonary 
vessels, and the impossibility of observing the correspond- 
ence of the change, of velocity in the circulation, with the 
colour of their blood. 

The phenomena of the respiration of man, and those of 
the functions which are dependent on it, can be illustrated 
only by experiments made upon animals with a double 
ventricle, with a complete pulmonary apparatus, possessed 
of a temperature superior to that of the atmosphere, and 
the two separate systems of venous and arterial blood ; 
but on the other hand, In the mammalia resembling man, 
their respiratory apparatus, the thickness of the vessels 
and cavities of the heart, impede the view of the blood 
which they contain ; and experiments made without an 
absolute inspection of the 'fluid there, can only give us 
approximations. The indecisive experiments of former 



254 PHYSIOLOGICAL RESEARCHES 

physiologists oa this subject were my motives for the 
present inquiry. 

One of the best methods of judging of the colour of the 
blood, consists as I have often said, in fixing a tube witli 
a stop-cock to the trachea. By this, the influx of air into 
the lungs, may be regulated or altogether stopped. By 
this, we may distend the organ, or entirely evacuate it ; 
it gives us also the facility of introducing whatever gas 
we please. The animal breathes very well by such pipe 
when it is open, and would live with it for a considerable 
length of time without any very great alteration in its 
functions. 

In the second place, ah artery, the crural or carotid for 
instance, must be opened with the view of observing the 
varieties of colour in the blood projected from it. A 
small artery should not be chosen. From such a one the 
course of the blood would be suspended by the slightest 
accident; and on the other han^d, tlie' larger arteries 
expend in a little time toa large a quantity* of blood; this 
inconvenience may be remedied, by adapting to these 
vessels a tube of a small diam6t^^T6k<^ a stop-cock. 

All things being thus prepared, on a dog, for instance, 
let us see what are the phenomena which take place, when 
the colour of the blood is altered. In my indication 
of these, however, I shall speak only of what. I have 
seen, and by no means pretend that in man their duration 
should be similar or uniform, or even tfa^t in animals 
of the same species, under the different circumstances of 
sleep, digestion, exercise, and passion, &c. if it were 
possible in such way to repeat them, they should be alike. 
The instability of the animal functions, as I have said, is 
extreme ; they cannot be submitted to calculation ; they 
remain indeed the same, but their variations as to plus or 
minus are innumerable. 



ON LIFE AND DEATH. 255 

Let us now return to our subject : 

1st. If the cock of the. pipe be shut immediately after 
the animal has inspired , the blood begins to be altered in 
colour at the end of about thirty seconds. — At the end 
of a minute its colour is dark; at the end of a kninute 
and half or two minutes, it is perfectly similar to venous 
blood. 

2dly. If the cock of thé pipe be shut inrimediately after 
the animal has expired strongly, the blood receives its 
tinge of black some seconds the sooner. 

3dly. If the air of the lungs be plimped out entirely 
with a syringe, the blood will suddenly pass from red to 
black.* ' In such case it appears that the artery immedi- 
ately throws- out a black stream^ after it has expelled the 
red blood which it previously contained. There is no 
gradation. The blood is expelled by the arteries, such as 
it is in the veins. 

4thly. If, instead of making a vacuum in the lungs^ 
we inflate the air cells to the full, the blood is a longer 
time in becoming black, a minute at least, and is not com- 
pletely black before the end of three minutes. — This will 
vary according to the quantity of air injected. 

From all these experiments it follows, 1st, That the 
length of tbe Interval,- during which the blood retains 
its red colour, is in direct proportion to the quantity of 
air contained in the lungs ; 2d ly. That as loiig as there 
remains any quantity however small of respirable air in 
the cells of the lungs, the blood will preserve more or 
less of its crimson colour ; 3dly, That this colour dimin- 
ishes in proportion as the respirable air diminishes ; and 

* It is not possible to remove bj this means a great portion of air 
contained in tbe lungs, for the last ramifications of the air-tubes b> ing 
flexible, their parietes soon come in contact, and thus oppose the exit 
of the air contained in tbebronchial cells. 



256 PHYSIOLOGICAL RESEARCHES 

4th1y, That the blood is cxacftly similar to that of the 
veinsy as soon as the whole of the vital air- in the extremi- 
ties of the bronchiae has been exhausted. 

In my different experiments with regard to asphyxia, 
I have remarked, that if after shutting the cock of the 
syringe, the animal agitate the chest by similar move- 
ments to those of inspiration and expiration, the blood 
is a longer time in losing its red colour, than In the case 
where the breast remains at rest. Such motion, and 
agitation must cause a circulation of air in the cells, in 
consequence of which, a greater number of its points 
must be presented to the circulating fluid. My experi- 
ments which I shall presently detail on the breathing of 
animals in bladders, will prove the truth of the above 
explanation. 

At present I pass to a contrary set of phenomena — to 
those which are exemplified when the blood regains its 
arterial colour during the period, which, from a state of 
asphyxia, restores the animal to life. 

1st. When the cock, which for some minutes has been 
shut, is opened, the air immediately penetrates into the 
bronchiae ; but previously the animal expires strongly. 
Six or seven large inspirations and expirations follow 
each other precipitately. The artery being now examin* 
ed, a jet of a very vivid colour is seen succeeding to the 
efflux of black blood, and takes place. in thirty seconds at 
most, from the time of opening the tube. This is the 
inverse of the phenomenon above described. There are 
no successive shades perceived from black to red ; the 
passage is instantaneous. The brightness of the colour 
seems even to be greater than is natufc*al. 

2dly. If instead of suddenly turning theeock, avery 
strong stream of air only be admitted, the colour is less 
lively indeed, but just as quickly regained. 



ON LIFE AND DEATH. £57 

Sdly. If there be adapted to the stop-cock a syringe 
full of air, and this fluid be pushed into the lungs, on 
Opening the pipe, and then the pipe be suddenly shut 
again, the blood will become red, but much less evidently 
80, than when the entrance of the air is owing to volun- 
tary inspiration. Here the portion of air injected must 
repel into the bottom of the cells whatever is already 
vitiated, while on the contrary, if the tube be simply 
opened, the vitiated air i^ at once rejected, and then 
replaced from without. The following experiment ap- 
pears to confirm this idea. 

'4thly. If instead of pushing air upon that which is con- 
tained in the lungs, we pump out the vitiated air in the 
first place, and then inflate the organ, the colouring prp- 
cess will be more rapid, and the colour of the blood 
itself especially, more lively than in the preceding case, 
though less so than in the first of this latter suite of expe- 
riments. 

Sthly. The lungs being exposed on both sides by a 
lateral section of the ribs, the circulation will continue to 
go on for a certain time. Now, if by means of a syringe 
adapted to the stop-cock in the trachea, the pulmonary 
vesicles be alternately emptied and dilated, the changes 
from red to black, and from black to red, will be observ- 
ed as in the above experiment, as long as the circulation 
lasts. 

The folHl^ing consequences may be inferred from the 
facts, which I have mentioned. 

1st. The rapidity with which the blood becomes red 

again, on opening the pipe in the trachea, is a plain proof, 

that the principle from which this colour is gained, must 

pass into the blood across the membranous parietes of the 

air cells, and not by means of the absorbents. I shall 

establish this fact hereafter upon other proofs. 

33 



25S PHYSIOLOGICAL RESEARCHES 

2dly. The celebrated experiment of Hook, in which 
the enfeebled movements of the hearts of animals in a 
state of asphyxia are accelerated by injecting air into the 
lungs, is very well explained. The red blood penetrates 
into the fibres of the heart, and puts an end to the debility 
induced, by the influx thither of the black blood. 

3dly. I do not believe, that motion can ever be restored 
to the heart, when once it has been wholly annihilated 
by the presence of venous blood. In this I have never 
succeeded, though I have often attempted it. Many 
authors, however, pretend to have done so. If the heart 
be reanimated by arterial blood, it is necessary at any 
rate, that such blood, should pass into it, now in what 
way can it arrive there, if the circulation have entirely 
ceased. 

We must observe, however, that there are two cases 
of interruption in the action of the heart from asphyxia. 
Sometimes there supervenes a syncope which arrests the 
movement of this organ, before the black blood has been 
able to produce such effect; and here it is manifestly 
eapable of excitement, from the presence of the red bloody 
just as it is from the application of any irritating cause ; 
but when it has been injected with venous blood, it then 
contains within itself the principle of its inertia, which 
can be removed only by the contact of arterial blood with 
it; but such contact is become impossible. 

I was very desirous of knowing what the influence 

might be of the different gases when inspired upon the 

-colour of the blood. Accordingly I successively adapted 

to the pipe different bladders, containing hydrogen and 

carbonic acid gas. 

The animal alternately swells andcantracts the bladder 
by the different motions of the thorax. It is calm at first, 
but at the end of three minutes^ begins to be agitated ; its 



ON LIFE AND DEATH, 259 

respiration is now hurried and embarrassed, and at the 
end of four or- five minutes, the blood of the carotid is 
black. 

Whichever of the two gases be employed, there is little 
difference in the above phenomena. This remark should 
be compared with those of the Members of the Institute, 
who have assured us that complete asphyxia supervenes 
only after an interval of ten minutes, with pure hydrogen, 
and at the end of two minutes with carbonic acid gas. 
The black blood must continue, therefore, to circulate for 
a longer time in one than in the other kind of asphyxia 
here spoken of. This circumstance confirms some reflec- 
tions which I shall have occasion to offer upon the differ- 
ence of asphyxiae. 

For what reason should the blood be a longer time in 
losing its colour, when bladders of non-respirable air are 
fixed to the pipe, then when the cock is simply turned ? 
The reason of this is evident, hy the different motions 
of the lungs, the air is expelled and reabsorbed, the res-* 
pirable portion of it must consequently be successively 
presented to the capillary orifices, by which it is trans- 
mitted to the blood. 

On the contrary, when the pipe is simply shut, the air 
it is plain has not the same influx and efSux ; in compari- 
son with such motion, it may be said to stagnate so that 
the respirable portion of that which is enclosed in the 
bronchial cells is exhausted, and the blood ceases to be 
coloured, though there remain in the trachea and its larger 
divisions, a considerable quantity of fluid, which has not 
been despoiled of its vivifying principle. .Of this we 
may be certain, after the death of the animal, by cutting 
the trachea under the pipe, and plunging a bougie into 
it. The process by which the blood gains its red colour 
appears to take place only at the extremities of the 




260 PHTSIOIjOGICAL RESEARCHES 

broochiae, the ioner surface of the larger aerial vemeb, 
has nothing to do with this phenomenon. 

We may convince ourselves of the reality of the expla- 
nation which I have offered, if we pump out the air of 
the lungs, before we fit the bladder to the trachea ; for in 
such case, the animal must breathe the air of the bladder 
without mixture. Here the change of the blood to black 
is almost sudden, but here also, as in the preceding experi- 
ment, there is little difference in the phenomena, whatever 
gas we employ. I have chosen the two gases above. men- 
tioned, because they enter into the phenomena of natural 
respiration. 

When we adapt to the pipe a bladder full of pure 
oxygen, the blood is very long in becoming black, but 

es not at first assume a redder tint than it usually has. 



II. Tht blood which has been blackened in consequence 
of the interruption of the chemical functions of the 
lungs penetrates into the organs ^ and circulates for 
some time in the vascular system tf the red blood. 

We have just established what are the phenomena of 
the alteration of colour in the blood, when the chemical 
functions of the lungs are suspended. Before we consider 
the influence of this change upon the death of the organs, 
let us prove, that they are really penetrated by the blood 
when so altered. 

I have proved it to be a fact, that the force of the heart 
subsists for some time, notwithstanding the influx of the 
black blood into it, and have shewn that the black blood 
is thrown out with a jet, similar to that of the red blood, 
&c. &c. Hence 1 might already conclude, Ist, That the 
arterial circulation continues for a certain time, though 
the arteries contain a fluid, to which they are not accus- 



ON LIFE AND DEATH. 261 

tomed, and 2dly, That the necessary consequence of such 
circulation, must be the injection t)f the different parts of 
the body with black blood ; but we shall deduce the latter 
conclusion from precise and rigorous experiments. To 
be certain of this important fact/ we have only to expose 
successively the different organs, while the animal is suf- 
fering a death of asphyxia. I have in this way examined 
the muscles, the nerves, the membranes and the viscera. 
The following are the results of my observations. 

1st. The colouring matter of the muscles, exists in the 
body in two states — at liberty, or in a state of combina- 
tion ; in the vessels, where it circulates with the blood, 
or in the fibres, with which it is combined. It forms 
especially the colour of the muscles, and in such state 
undergoes no alteration from asphyxia ; in its free state 
it is blackened. The divided muscles furnish an infinity 
of black drops, which are no other than indices of the 
divided vessels. Such drops contrast with the red of 
the muscles ; but when circulating within them, are the 
cause of that livid tin which they then present. 

2dly. The nerves are habitually penetrated by a number 
of small arteries, which creep along within their tissue, 
and carry to them both excitement and life. In the state 
of asphyxia the black blood by which they are traversed, 
is announced by the dull brown, which succeeds to the 
rosy-white, which is natural to them. 

3dly. There are few parts, where the influx of the black 
blood is more visible, than in the skin ; the livid spots so 
frequent in asphyxia, are only the effect of the obstacles 
which it meets with, in its passage towards the general 
capillary system, to the organic contractility of which it 
is not a su£Bcient excitant. To this cause also is owing 
the tumefaction of certain parts^ such as the cheeks and 
lips. This phenomenon we have seen already in the 



269 I'HYSIOLOGICAL RESEARCHES 

lungs, they cannot be traversed by the blood and therefore 
become in the last moments of life, the seat of a fulness, 
which affects the whole of the capillary system there; but 
for the reasons, which I have assigned, such fulness is 
always more evident in the capillary system of the lungs, 
than in that of the system in general. 

4thiy. The mucous membranes also, when the chemi- 
cal functions of the lungs are interrupted, exemplify a 
similar phenomenon. The swelling of the tongue, ob- 
servable in those that have been drowned or hanged, or 
asphyxiated by the vapour of charcoal, the lividity of 
the membrane of the mouth, of the intestines, and the 
branchiae which have also been remarked, depend on 
no other cause. The following is a proof of this asser- 
tion : 

Drag out of an animal a portion of the alimentary canal 
and divide it in such way as to expose its inner surface. 
Then shut up the pipe which has been previously adapted 
to the trachea, and at the end of four or five minutes, a 
brown tint will succeed to the red one, which is natural 
to this surface. 

5thly. I have made the same remark upon the fleshy 
granulations of a wound, inflicted on an animal, for the 
purpose of observing the manner in which they are colour- 
ed by the black blood. In the two last experiments, this 
phenomenon is slower in taking place than in many other 
circumstances. 

6th1y. The alteration of colour in the serous mem- 
branes is much more quickly effected than it is in the 
mucous membranes. Of this we may assure ourselves by 
comparatively examimng the outer and inner surfaces of 
the intestines, while the pipe in the trachea is shut ; in 
the serous membranes, the livid tint which they assume, 
depends upon thé vessels, which creep underneath them, 



ON LIFE AND DEATH. 263 

and not on the blood by which they are penetrated. 
Now as these vessels are considerable, the black blood 
must flow into them almost as soon as it is produced. 
In the mucous membranes on the contrary, and in all 
cicatrices, the colour which they take on in asphyxia, is 
made by the capillary system of the membrane itself, 
which system is much more tardy than the other, to 
receive the black blood, and to be penetrated by it ; so 
much so indeed, as to refuse it in some parts. I have 
many times seen the membrane of the nasal fossœ very 
red in asphyxiated animals, while that of the mouth has 
been quite livid, for there are parts into which as I have 
said the black blood will not penetrate at all, and then 
they preserve their natural colour. 2dly. There are 
others into which it evidently passes, but where it stops^ 
and then a simple change of colour is observed, if it have 
penetrated but in small quantity ; and again, if it have 
penetrated in a considerable quantity, together with such 
change of colour, there will be observed a tumefaction of 
the part. 3dly. In other cases, the black blood merely 
traverses the parts, without stopping in the capillary 
system, and passes at once into the veins, as the red blood 
does. 

In the first and second case, the general circulation 
experiences an obstacle which puts a stop to it in the 
general capillary system. In the third, which is much 
more universal, it is in the capillaries of the lungs that 
the blood is at last arrested, after having circulated in the 
veins. 

These two sorts of impediment coincide with each 
other, in many instances. Thus in asphyxia, a part of 
the black blood which circulates in the arteries stops 
in the face, upon the mucous surfaces, in the tongue, and 
in the lips^ while the other, and much the larger quantity. 



X ■ 



254 PHYSIOLOGICAL RESEARCHES 

finds no impediment in the general capillary system, and 
is finally arrested in the lunchs. 

What is the reason, why certain parts of the capillary 
system refuse to admit the venous blood, or if they admit 
it, do not pass it on to the veins ; while others are less 
enfeebled by it, and transmit it as freely as ever. All 
this must certainly depend on the relation existing between 
the sensibility of each part and the venous blood. 

I was desirous of making use of the power, which we 
possess, of changing the colour of the blood, for getting 
some insight into the influence of the circulation of the 
mother, upon that of the fcetus ; accordingly I procured 
a bitch big with young, and asphyxiated her, by closing a 
tube, adapted to the trachea. About four minutes after 
she had ceased to breathe, I opened her ; the circulation 
was going on. I then cut into the matrix, and exposed 
the cord of two or three of the fœtuses. The artery and 
the vein, were both of them full alike of venous blood. 

Had 1 been able to procure other bitches in a similar 
state, I should have repeated this experiment in another 
manner. I should in the first place have compared the 
natural colour of the vein, with that of the artery. In 
many of the young of the guinea pig, the difference 
appeared to me to be much less than it is in the adult 
animal. In many circumstances indeed I could perceive 
no difference whatever. Both the arterial and venous 
blood were equally black, though the respiration of the 
mother was in no wise impeded by the opening of the belly. 
Secondly, I should have closed the tube in the trachea, and 
then have observed whether the change in colour of the 
umbilical artery of the fœtus (supposing the blood of the 
artery to be different from that of the vein) were corres- 
pondent with that, which would inevitably take place in 
the blood of the mother. Experiments made with a 



ON LIF£ AND DEATH. 2&6 

view to these circumstances, and ofi lar«^ animals^ might 
probably throw much light upon the mode of communi- 
cation, between the mother and the fœtus. Observations 
are also much to be desired, with respect to the colour of 
the blood in the human fœtus, and the cause of its passage 
from a livid colour, to the very marked red which it 
assumes, some little time after birth.* 

I {night add a number of examples to these, which I 
have already related of the blackening of the organs by 
the venous blood. Thus, the kidney of a dog expose^» 
while the animal is dying of asphyxia, is much more 
livid than in its natural state, the spleen also and the liver, 
when divided, emit only black blood, instead of that 
mixture of red and black blood which is observable, in 
the section of these organs, upon an animal which breathes 
freely. 

But I trust that we have facts enough to establish it as 
a certainty, 1st, That the black lîlood after the interrup- 
tion of the chemical functions of the lungs, Continues for 
some time to circulate, and 2dly, That it penetrates into 
the organs, where it replaces the red blood ; these circum- 
stances explain the reason, why on opening the body we 
always meet with black blood even in the vessels which 
are destined for the circulation of arterial blood. 

In the last moments of existence of whatever death 
the individual may have died, we shall always observe the 
lungs become embarrassed and cease to perform their 
office, for some time previous to the total suspension of 
the functions of the heart. The blood makes its circle 
through the system, afler ceasing to recefve the influence 
of the air, and consequently in its venous state; accord- 
ingly it must rémain so in the organ in every case, although 

* These observations have been made on the great mammalia^ and 
there has not been remarked any difference of colour. 

34 



266 PHYSIOLOGICAL RI «EARCHES 



é 



the circtilatioQ be much less evident, than in asphyxia, for 
it is in this circumstance that consists, the g;reat peculiarity 
of asphyxia. The following phenomena may now be 
easily understood. 

1st. When the left auricle and ventricle together with 
the lar^e divisions of the aurta, on opening the body, 
are found to contain blood, such blood is always black. 
The fact is familiar to those who are in the habit of 
dissecting. In exercising my pupils on the surgical opera- 
tions, I have always observed that when the open arteries 
are not entirely empty, their contents are composed of 
venous blood. 

2dly, The corpus cavernosum is always gorged with 
this sort of fluid, whether flaccid or in a state of erection. 
For I have seen it in the latter state hi two subjects 
brought to my amphitheatre. One of these men had 
hanged himself, the other had died of concussion of the 
brain. 

Sdly, The blood which is found in the spleen is never 
red ; but sometimes on the exterior, and sometimes on 
the concave surface of this organ, I have, observed spots 
of a scarlet colour, for which I cannot account. 

4thly, After death, the mucous membranes lose the 
red colour by which they are characterized during life. 
They assume a black and livid hue. 

5thly, Blood extravasated in the brain of persons in a 
state of apoplexy, is almost always found to be black. 

6thly, Sometimes, instead of accumulating inwardly 
the blood injects the surface of the body. In such case 
the face, the neck, and shoulders swell, and are infiltrated 
with blood. I have frequently remarked this sort of 
phenomenon in the subject, but have never found' it coin- 
cide with any internal extravasion. — The colour of the 
ski*> is then of a purple or deep brown, an evident sign 



ON LITE AND DEATH. 267 

of the sort of blood with which it is iojected, and is 
evidently produced by the stagnation of the black blood 
in the extern^il capillary system, not by the reflux of the 
blood from the veins. 

I shall not dwell any lons^er upon the numerous consé- 
quences^ of the above established principle. I shall only 
observe, that when death commences by the circulatory 
system, the preceding phenomena are not to be remarked^ 
or at least very little perceptible. 

Let us now pass on to the influence of the black blood 
upon the organs of which it penetrates the tissue. 

III. The black blood which pénétrai es the organs, as 
soon as the chemical functions of the lungs have ^ 
ceasedy will not maintain them, in a state of life and 
activity. 

To determine what the influence of the black blood is 
upon the organs, I shall first remark, that the property of 
the red blood is to stimulate them, and keep up their vital 
actions. This will be proved by the following observa- 
tions : 

1st, Compare phlegmon, erysipelas, and inflammatory 
tumours (to the formation of which the red blood is 
essentially requisite) with scorbutic spots, and petechias, 
produced by the black blood. The first will be found 
connected with the exaltation of the vital powers, the 
second with their depression. 

2dly, P^xamine two men, the one with a rosy coloured 
skin and large breast, announcing vigour of lungs, the 
other with a pale and sallow countenance, and narrow 

■ 

chest : in these the vigour of the chemical combinations 
which are made in the lungs, should certainly be very 
different. 



263 PHYSIOLOGICAL RESEARCHES 

ddly. The greater number of ganer^nes in old men, 
b^n with a lividity in the part, a lividity which is 
evidently the index of the absence or diminution of the 
arterial blood in the part. 

4thly, The redness of the branchiae of fish is always 
the sign by which their rigour may be recognised. 

5thly, The redder the granulations of wounds, the 
more healthy is their nature ; the paler or browner they 
are, the less has the part a tendency to cicatrise. 

6thly9 The lively colour of the face, and the ardent 
eye» coincide with the energy of the cerebral actions in 
certain fevers. 

7thlyy The more developed the pulmonary system of 
animals, the more active are the chemical processes of the 
lungs, and the more deveroped and perfect the general 
life of their different organs. 

8thly, Youth, which is the age of vigour, is that also 
•when the red blood predominates in the system. The 
arteries of old people are smaller, the veins larger than 
those of the young. It is a fact universally known, that 
at the two extremities of life the proportions of the two 
vascular systems are inverted. 

I am ignorant of the manner in which the red blood 
excites and keeps up the life of the parts. Perhaps the 
principles by which it is coloured become combined with 
the different organs to which it is distributed. In fact 
there is a considerable difference between the phenomena 
of the general and those of the capillary system. 

In the first, the blood in changing its colour, leaves 
behind it the principles which made it red ; in the second, 
the elements to which its blackness is owing, are rejected 
by respiration and exhalation. Now, this union of the 
colouring principles of the arterial blood, may probably 
•onstitate a material part of the excitement which is 



ON LIF£ AND DEATH. 269 

necessary to the action of the organs. — If such be the 
ease, the black blood as it does, not contain the materials 
of such union, cannot act as an exciting cause. This idea, 
however, I offer only as a probability, and am by no 
means prepared to defend it as a truth ; it may be ranked 
on a par with that of the sedative action, which I have 
said may be excitçd by the black blood on the different 
parts— «for, however probably an opinion may appear, 
there should be no real importance attached to it as an 
opinion only. 

Without regard then to any system, let us inquire 
how the black blood, from its contact with the various 
parts, is the occasion of their death ; how it acts on the 
parts of the animal life, and how it acts on those of the 
organic life. 

All the organs of the animal life depend upon the 
brain ; now, we have seen that the black blood paralyses 
the cerebral powers almost suddenly. In the state then 
of asphyxia, the locomotive, the vocal and sensitive 
organs, must be inactive.* From the same cause, their 
exercise must be suspended in all those different experi- 
ments where black blood is injected into the brain, the 
other parts receiving the red blood as usual. But when 
the black blood circulates throughout all the system, 
when the whole of the organs, as well as the brain, are 
submitted to its influence, then there are two other causes 
of death coniiected with those which have been mentioned. 

1st, The nerves, which are pe«etrated by it, for that 
very reason are no longer capable of keeping up the com- 
munication between the brain and the senses on the one 
hand, and on the other, between this same viscus and the 
locomotive or vocal organs. 

2dly, The contact of the black Blood with these organs 
themselves annihilates tlieir actions. Inject the crural 



270 I'HYSIOLOGICAL RESEARCHES 

artery of an animal with the black blood taken from one 
of its veins, and the movements of that member will be 
shortly aflerwards enfeebled, or wholly paralyzed. In 
this experiment, the upper part of the artery, for manifest 
reasons, should be that to which the pipe of the syringe 
should be fixed. 

I am aware that as to this experiment, it may be assert- 
ed that the ligature of the artery, of itself, is capable 
of p.iralyzing the limb. In fact, such circumstance has 
happened twice with me, but I have also had occasion to 
observe, that it does not necessarily follow the ligature 
of this vessel, as it does the ligature of the aorta : when 
the latter vessel is tied, -all movements cease at once ; 
notwithstanding all which, the result of the injection of 
black blood, is almost constantly that which I have assert- 
ed it to be ; — I say almost, 1st, Because I have once seen 
it fuil in its effect, though done with the requisite precau- 
tions; îiclly, Bffcausc the debility, which is induced, both 
in duration and dei;ree, will be according to the strength 
of the animal on which the experiment is made. 

There is also occasioned in this experiment, a manifest 
su*<ponsion of the sensibility of the animal ; it is not 
indeed so ready to appear as the loss of motion ; but it 
always comes on, especinlly if the injection of the black 
bloud be repeated three or four times, with small intervals. 

A similar, but a more tardy effect may be produced 
by adapting to the canula, which has been placed in the 
crural artery, of an animal, a tube which has been pre- 
viously fixed to the carotid of another animal, and then 
by asphyxiating tlie latter.* The organs of the internal 

* The difference tliat i^ remnrkt^d in the resaltd of iWis experiment, 
conipar^'d with that in which the venoas blood is introduced by rnean^ 
of -a'sjrinire, ariffs probably from this, that in the firçt the blood that is 
forced into the artery has already beg;un to coagulate. 



ON LIFE AND DEATH. 271 

life are not dependent on the brain, and therefore are 
not affected by the suspension of the cerebral action in 
asphyxia.. It is the influx of the black blood which is the 
immediate cause of their death. 

I have already demonstrated what the influence is of 
this blood upon the organs of the circulation. We hare 
seen how the heart ceases to act, as soon as it is penetrated 
by it ; it is owing in part to the injection of the arterial 
and venous parietes themselves, by the vasa vasorum, that 
the vessels are forced to suspend their actions. 

It will be always a difficult thing to prove, that the 
secretions, the exhalations, and the process of nutrition, 
could not be made from venous blood, because the circula- 
tion of this sort elf blood in the arteries, does not continue 
for a sufficient time, to allow of observations, or the 
manner in which these functions would be affecte3 by it. 
On this subject, however, I have made some essays. 1st, 
I exposed the inner surface of the bladder of a living 
animal, after having previously divided the symphysis 
pubis, and opened the lower belly, I then examined the 
oozing of the urine from the orifices of the ureters, 
while I asphyxiated the animal, âdly, I divided the vas 
deferens, with the view of observing, whether the semen 
would flow or not, during such state. 

In general, I have had occasion to remark, that during 
the circulation of the black blood in the arteries, no fluids 
appear to issue from' the different secreting tubes. But I 
confess, that in all these experiments, and in other similar 
ones which I have made, the animal is too much agitated, 
and the limits of the experiments too circumscribed, for 
any thing like a well founded judgment to be formed 
on the subject in question. It is chiefly from analogy, 
then, that I am led to conclude, that the black blood is 
unfit for the purposes of exhalation and nutrition; such 



272 PHYSIOLOGICAL RESEARCHES 

« 

supposition also accords well with divers of the phe- 
nomena of asphyxia. — Ist, The want of exhalation from 
the skin during the slate of asphyxia, is probably the 
reason of the phenomena of the animal heat in such sort 
of death.* 2dly, In asphyxiating animals very slowly 
during digestion, I have uniformly observed, that the bile 
ducts, and duodenum, contain a much less quantity of bile, 
than they do at such time, when these parts are exposed 
in the living animal. — 3d]y, As the blood loses nothing 
from the exercise of these functions, it must of course 
accumulate in the vessels ; and in fact it is very fatiguing 
and unsatisfactory, to dissect the bodies of those who 
have been hanged or asphyxiated with the vapours of 
charcoal, from the fluidity and abundance of their blood. 
But this abundance, perhaps, may depend upon the 
weakness of the absorbents. In other sorts of death, the 
absorbents continue for some time to act upon the serous 
portion of the blood remaining in the vessels. ' In asphyxia 
there is neither secretion nor absorption. 

The excretions also appear to be afifected much in the 
same way. The bladder of asphyxiated persons has been 
observed by Portal, to be very much distended. Such 
distensjon, no doubt is occasioned by the urine already 
secreted before the accident which was the cause of their 
deaths. In general, the asphyxise which are occasioned 
by the circulation of the black blood unmixed with any 
deleterious substance, are not accompanied with those 
spasms, which in so many other sorts of death^ are so 

* The dçûciency of cutaneous eihalation in the last moments of life 
may contribute a little perhaps to the preservation of animal heat ; but 
we have shown that there are other mok^ powerful causes for this phe- 
nomenon. This deûcioncj of exhalation united to the inaction of the 
secretory organs, in the very siiort period in which the black blood rum 
in the arteries i^ an altogether insufficient oaose to explain the abun- 
dance of blood that is found in the vessels of those who have died of 
asphyxia. 



ON LIFE AND DEATH. jgTÔ 

frequent. These spasms, which evacuate the organs of 
their fluids, should be carefully distinsiuished IVoni the 
•impie relaxations of the sphincters, by which analogous 
efifects are produced.* In asphyxia, all is debility, ia 
asphyxia, we never see that augmentation of life, that 
development of power, which so frequently mark the 
latter movements of the dying. 

Hence also perhaps, the great flexibility of the members 
of asphyxiated persons. The stififiiess of the muscles 
appears to depend in many cases, on the circumstance of 
death having come on precisely at the moment of their 
contractions. The fibres remain approximated, and cohe- 
rent among themselves ;t in as|)hyxia, on the contrary, as 
there exists an universal relaxation and want of action in 
the parts, they remain so after death, and yield to what- 
ever impulse may be communicated to them. 

I confess, however, that this explanation is subject to a 
difficulty which I cannot solve. Persons asphyxiated by 
xnephetic vapours, perish nearly in the same vvay as those 
who are drowned ; if the cause of their death be different, 
its effects are the same, as may be seen by opening the 
carotid of two dogs at the same time, that Into the lungs 
of the one are injected the vapours of charcoal, and into 
those of the other, a certain quantity of water, which 
water, as in the drowned, is soon reduced into a state of 
foam. 

♦ This is not an uniform fact, and it is even very common to find, in 
périmons who have been liung, the bladder completely umpty. 

■|- The moment respiration ceasos, and Ihu (>ource of heat is conse. 
quently cut off, it is not u^(oiii«l)iiig[ that an animal body should become 
cold quicker in %Vbter then in a much less dense fluid, like the air. It 
should also be remarked that the wafer, on account of the evaporation 
that takes place on its surface, has almost always a temperature below 
tbat of tli« surrounding air. 

35 



974 PHYSIOLOGICAL RKcEARCHES 

Notwithstanding this similitude of the last phenomena 
of life in the two cases, the members in the fjrst remain 
for a certain time warm and supple, while those in the 
second, especially if the body be plunged into water 
during the experiment, become very suddenly stiff and 
frozen. Let us return, however, to our subject. We 
may conclude from the various facts and considerations 
related in this «chapter, 1st, That when the chemical 
functions of the lungs arc suspended, the functions of all 
the other organs are suspended also, from the presence 
of black blood within their substance. 2dly, That the 
death of the organs in general, coincides with that of 
the brain, and the heart, but is not immediately derived 
from them. 3dly, That if it were possible for the brain 
and heart to receive an influx of arterial blood, while 
the others were dying, from that of the venous blood, 
they would doubtless continue to exert their accustomed 
actions. 4thly, That, in a word, asphyxia is a general 
phenomenon, developed at the same time in all the organs^ 
but especially in one of them. 

From this manner of regarding the influence of the 
black blood upon the different parts of the body, it appears 
that death is very soon the result of its circulation in the 
arteries. Nevertheless, certain organic defects have 
sometimes prolonged after birth, the mixture of the two 
sorts of blood, a mixture which is known to be made in 
the fœtus. Such was the malconformation mentioned 
by Sandeford, in a child, the aorta of which arose by a 
branch from each of the ventricles. Such also appears, 
at first sight, to be the opening of the foramen ovale in 
the adult. 

We shall remark, however, that the existence of this 
foramen, does not suppose the passage of the black blood 
into the red-blooded auricle, as is generally believed. 



ON LIFE AND DEATH. ' f75 

For the two semi-lunar valves, between which it is gitu- 
ated when met with afier birth, are necessarily applied to 
each other by the pressure which the blood contained in 
the auricles, exercises upon them, when these cavities are 
simultaneously contracted. The foramen must be at such 
time shut, and its obliteration much more exact, than that 
of the opening of the ventricles, by the mitral and tricus- 
pid valves, or that of the aorta and the pulmonary artery, 
by the sigmoid valves. With all this, the foramen ovale 
is actually very often found open in the subject, and when 
not so, nothing is easier than to destroy the species of 
adhesion which is contracted by the two valves which 
close it. This may be done with the handle of a scalpel^ 
without any solution of continuity, the parts appear to be 
unglued. 

The oval hole when in this way artificially made, pre- 
sents the same disposition, with that which is sometimes 
exemplified in the carcase. Now if this disposition be 
examined, it will be seen that when the auricles contract, 
the blood must make an obstacle to itself, and that it 
cannot pass from one into the other of these cavities. It is 
an easy thing to be convinced of the mechanism of which 
I speak, by means of two injections of a different colour, 
made at the same time from both sides of the heart, from 
the vena cava, and the pulmonary veins. 

From what we have said of the influence, which is 
exercised by the movement and the different principles 
of the blood, it is evident that the death of the white 
organs must be different from that of the red ones. 
Asphyxia can hardly reach them, but of the manner in 
which they die I confess that I know but little. 



1176 PUT310L0GICAL R£[SCARCHl!:S 



CHAPTER IX. 

or THE INFLUENCE OF THE DEATH OF THE LUBTOS, OVER 
THE GENERAL DEATH OF THE BODY. 

In recapitulating what has been said in the preceding 
chapters with respect to the influence of the lungs over 
the heart, the brain, and all the organs, it is an easy 
natter to form an idea of the successive termination of 
the whole of the functions, when the phenomena of respi- 
ration are suspended either mechanically or chemically. 

The following is the manner in which death supervenes, 
when the mechanical phenomena of the lungs are inter- 
rupted, either fiom the causes mentioned in the 5th 
chapter, or from similar ones, such as the rupture of the 
diaphragm, which i have twice had occasion to observe,* 

* When thf Hiaphrd&:m h ruptured, a sudden cesiiafioD of the fuDctiona 
is not alnay» the result of this accident. Patients huye been known to 
survive many day«, and the cause of death has only t>een ascertaineâ 
hy exanjining the body. 

The intercostal muscles are, in this case, the sole agents of respira- 
tion, which become» nearly analogous to that of birds or to that of 
animals with red and cold blood, who are destitute of the septum 
between the thorax and abdoinentf 

Lit^utciud cites various ruptures of the diaphragm, produced by other 
oause»- than external injuries. Uiemerbroech has seen this muscle want- 
ing in an infant who still lived to the age of seven jcars. 

f When from any cau^e, the diaphragm cannot contract, the enlarge- 
ment of the thorax is effected solely by the elevation of the ribs, aud 
as this motion is then very evident, we can then appreciate better 
the influence the rntercostal muscles have in its production in ordinary 
respiration. Haller, as is well known, supposed that the £rst rib was 
almost immoveable, and that the muscles in the first intercostal space, 
took it at their fixed point to elevate the second. This second rib, in 



4 



*<L 



ON LIFE AND DEATH. 2TJ 

or from a fracture of a great number of the ribs, or the 
sternum. 

1st. The mechanical functions of the lungs cease. 2d\y. 
The chemical functions of the lungs cease also. 3dly. 
The cerebral actions are put an end to. 4thly. The ani- 
mal life is interrupted. 5ihly. The general circulation 
is interrupted. 6thly. The capillary circulation is inter- 
rupted. 

The phenomena of death, are differently concatenated, 
when they begin by the suspension of the chemical 
functions of the lungs : which may happen, 1st, From 
breathing in a vacuum : 2dly, From the obliteration of 
the passage of the trachea, by foreign substances introduc- 
ed into it, or by tumour from without, or strangulation, 
accumulation of fluid in the air cells, &c. ; 3dly, From 
different inflammatory affections, schirrhi, &c. of the 
cavities of the mouth or throat. 5thly. From want of 
respirable air, as on the summit of high mountains. 6thly, 



its turn, served as a fixed point to elevate the third, and thus on to the 
last rib. But if we observe the mechanical phenomena of respiration 
when the diaphragm does not contract, as is the case in diaphragmatic 
pleuris^r, we see that the first rib is far from beins: immovcabJe.. Now, 
we cannot conceive how the intercostals which are attached to its 
inferior part, can, by contrac^ting, assist in raising it. Besides, in order 
to elevate the ribs, a very great resistance must be overcome, and the 
intercostal mascles are too slender to indace us to suppose that they 
are capable of effecting it. The principal agents of this motion then 
are the anterior and posterior scaleiii, which are distinctly seen to con- 
tract in great inspirations, the supra costales and the muscles of the 
neck which attach it to the sternum. We ought to add to these a 
Siascle, to which this use has never before been attributed ; I mean the 
diaphragm. This muscle in fact in its contraction tends to become fiat, 
from being concave as it is in inspiration. Now, its middle part in 
depressing the abdominal viscera experiences a certain resistance, and 
takes, as it were, from them a fixed point, by means of which it elevates 
the ba8« of the thorax to which its circnmference is attached. 



i 






278 PHYSIOLOGICAL RESEARCHES 

From the introduction into the air cells, of non-respirable 
gaseSy &c. &c. In all these cases^ the following is the 
order of the phenomena of death. 

1st. The chemical functions of the lungs are suspended. 
2dly. The functions of the brain are interrupted. 3dly. 
Sensation, locomotion, the voice, the mechanical phe- 
nomena of respiration cease. 4thly. The action of the 
heart, together with the general circulation is annihilated. 
5thly. The capillary circulation is- put an end to, together 
with the processes of secretion, exhalation, absorption, 
and digestion. 6thly. The animal heat of the system 
dies away. 

I. Remarks Upon the differences of asphyxiœ. 

The influence of the black blood as I have said, is 
always the great agent in this double sort of death, but 
it is not the only one : if that were the case, the phe- 
nomena of all the asphyxias would be alike. It is true 
that in every sort of asphyxia, the black blood ceases to 
become red blood, and circulates in the arteries, such as 
it is in the veins ; but notwithstanding the uniformity of 
this phenomenon, there can be nothing more varied, than 
the symptoms and progress of the^se accidents. In some 
of them, death is long in taking place ; in others, almost 
instantaneous : the phenomena developed in the last 
moments of existence, are alike in none of them. The 
state of the organs, and that of the powers which they 
preserve after death, are as various. 

Ist, Asphyxia varies with respect to its duration ; in 
sulphureted hydrogenous gas, in nitrous gas, and certain 
vapours arising from privies and sewers, it is quick in 
taking place. In carbonic acid gas, azot, in pure hydro- 
gen, water, and a vacuum, its progress is slower. 






^ -^ 



ON LIFE AND DEATH. 27^ 

2d\jj Asphyxia varies with respect to its attendant 
phenomena. At times, the animal is violently agitated 
and suddenly convulsed ; at others^ it appears to lose its 
powers gradually ; to pass into a stale of sleep, and from 
sleep into a state of death. In comparing the numerous 
effects arising from the vapours of sewers, from those of 
charcoal, from the different gases, from drowning, and 
other causes of asphyxia, We find them almost as various, 
as the causes themselves. 

3dly. The phenomena which make their appearance 
after death, are as variable. Compare the cold and frozen 
carcase of a drowned roan, with the remains of one who 
has been suffocated. Read the result of the' different 
experiments of the Institute, upon the affections of the 
galvanic fluid in the different asphyxias ; examine Halle's 
detail of the symptoms which accompany the mephitism 
of sewers; approximate the numerous observations, which 
arc scattered about in the works of Portal, Louis, Haller, 
Troja, Pechlin, Bartholin, and Morgagni; repeat the most 
common experiments on the submersion, strangulation, 
and suffocation of animals ; and you will observe the 
greatest difference in all these sorts of asphyxia, they are 
each of them characterized, by a peculiar state of the 
bodies of the animals, which have been submitted to 
the experiment. 

To inquire into the causes of such differences, vre must 
first divide the asphyxias into two classes. 1st, Into those 
which happen from the simple want of respirable air, and 
2dly, Into those, where to this first cause is joined also 
that of the introduction of some deleterious substance 
into the lungs. 

In the first class, the immediate cause of death, appears 
to be the simple presence of the black blood, in the vari- 
eus parts of the body, the general effect of which is always 



4 

1. 






S80 rHTSIOLOGICAL RESEARCHES 

the same, in whatever manner produced; accordingly, the 
attendant symptoms and secondary results of all these 
sorts of death, are nearly alike, their duration the same, 
and if it varies, it varies only in consequence of the more 
or less complete interriiption of the passage of air into the 
lungs. 

This variety in the duration and intensity of the 
asphyxiating cause, may nevertheless occasion some vari- 
ety in the symptoms also; such as a greater or less livtdity 
and swelling of the face, a more or less considerable 
embarrassment of the lungs ; but all these dififerences 
indicate only so many modifications of the cause. 1st, A 
man who is hanged, does not die as a man who is suffo- 
cated by an inflammatory tumour, or a pea or bean which 
perchance may have fallen into the trachea.* 2dly, An 
animal will perish much more slowly under a vessel of 
air, than when the trachea is tied. 3dly, The symptoms 
of asphyxia, when occasioned by a great rarefaction of air, 
or by a suffocating heat, are much less slowly produced, 
than where the cavity of the lungs is opened. 

In all these cases the cause of dea*h, namely the absence 
of red blood in the arterial system, is simple and unique, 
but according to the greater or less oxygenation of the 
venous blood, will be the appearances after death, for the 
longer the process of asphyxia endures, the less irritability 
will there be found in the system. 

But if the cause of asphyxia, have been the introduc- 
tion of some deleterious fluid into the lungs, then the 

* Asphyxia is not always the cause of death in those who are bung, 
there is sometimes connected with it a more efficient cause, which 
consist» in the compression of the spinal marrow. This was formerly 
very often observed in those who had been executed, because the 
executioner in throwing them off gave a rotatory motion to the bod^ 
which produced the luxation of the first vertebra on the second. 



ON LIFE AND DEATH. - 281 

variety of the symptoms will depend upon the difference 
in the nature of the fluid. In these cases the cause is 
of two kinds: 1st, There is no red blood in the system. 
2dly, A pernicious fluid is present in the system. AH 
the gases however do not act as deleterious substances : 
in pure hydrogen for instance, the animal perishes only 
as it would from the want of respirable air. ' 

But when a man in descending into a common sewer, 
into a cellar, or into any place where putrid matters arc 
accumulated, fails into asphyxia at the moment when he 
inspires their exhalations, and when such statels attended 
with convulsive movements and extreme agitation, then 
indeed, there must be something more in the cause of his 
death, than a simple suspension of the chemical functions 
of the lungs. 

In fact, together with the mephitic vapour, there con- 
tinues to enter into the lungs a sufficient quantity of air 
to keep up life and its different functions. 2dly, Suppos- 
ing even that the quantity of mephitic air were such as 
to leave no place for the entrance of respirable air, still 
the death ensuing should only be gradual, without agi- 
tation and convulsion, were it occasioned only by the 
absence of such air: now the very different way in which 
it supervenes, very evidently indicates the action of a 
deleterious substance, upon the animal œconomy.* 

* By injecfing info the veins different irrespirable gases, Nysten baa 
been able to distinguish the effects which result from the deleterious 
properties of the gases from those which arise from the alteration of 
respiration from a want of atmospheric air. 

Thus among the elastic âuids which be tried, he fouiid sulphuretted 
hydrogen, the deutoxide of azote, chlorine and ammoniacal gas emi- 
nently deleterious ; for introduced in sufficient quantity into the animal 
economy they uniformly cause death, whilst others, such as oxygen, 
azote, hydrogen, carburetted hydrogen, carbonic acid, oxide of carbon, 
and protoxide of azote do not produce death when introduced into the 

36 



282 FIJY&IOLOGICAL RESEARCHES 

These two causes theo act together, in those asphyxias 
which are produced by certain gases, sometimes the one 
predominates, sometimes the other. If the deleterious 
substance be violent, it kills before the action of the black 
blood can have produced much effect, if weak, it is the 
black blood, which is principally the cause of death. 

The asphyxiae then, which are produced by the fisses, 
differ only, in consequence of the nature of the deleteri- 
ous substance, which varies adinfinitum. In some of the 
aeriform fluids indeed it is supposed to be known, but in 
the greater number of them it is not so :* I shall notice 
therefore in a general way the effects, which result from 
the action of the deleterious substance, remarking at the 

longs, except bjr excluding the only inixtare, that can support respira- 
tion ; in no other way do thej occasion death, at least in a sudden manner, 
ir boweTer, tbej are thrown quickly into the blood yesself, they cause 
death, but it it mechanically and in the same way as atmospheric air 
would do it« U ahould al«o be observed that these different gases do 
not all act in the same way when they are introduced into the lungs ; 
the gaseous oxide of carbon destroys animals much quicker than axote 
or the protoxide of azote. They die also quicker in the prot-phosphu- 
retted hydrogen, and even in the carbonic acid gas. There are also in 
the action of deleterious gases certain anomalies which have not hitherto 
been explained. Nysten injected, at three injections, into the veins of 
a dog of middle size thirty centimetres of sulphuretted hydrogen. The 
animal after the first injection, was agitated, and made powerful inspira- 
tions; the second produced convulsive motions and the third apparent 
death ; but the next day he was entirely well. Now a less quantity of 
sulphuretted hydrogfen carried into the organs of respiration and mixed 
with five or six handred times its volume of air, would infallibly destroy 
the animal. 

'^The composition of some of these vapours is better known at the 
present day ; but there are others in which our means of analysis have 
been unable to detect the deleterious principle ; thus in the malaria^ 
which has depopulated the country in the neighbourhood of Rome, our 
chemists have as yet only found as constant elements, those which enter 
into the eonposition of atmospheric air. 



A 



ON LIFE AND DEATH. 283 

same time, that the symptoms by which they are display- 
ed, are strongly or weakly marked, according to the age 
and temperament of the individual. 

Deleterious suiDstances introduced into the lungs, to* 
gether with the mt^phitic vapours of which they form 
a part, can act only in two wavs, 1st, By affecting the 
nerves of the lungs, which re-act on the brain. 2dly, By 
passing into the blood, and exercising their influence, by 
means of the circulation on the various organs of the 
system. 

I can easily believe that the simple action of such a 
substance on the nerves of the lungs, may have a very» 
marked effect on the economy, and be capable of troubling 
the functions of the system very sensibly ; much indeed 
in the same way as with some individuals a mere odour, 
or the sight of a hideous object, will occasion syncope, in 
the same way that an irritating enema will suddenly 
awake the svstem into life, or the introduction of certain 
substances within the stomach, will be felt throughout 
the body, before such substances can have passed into the 
circulatpry torrent. We meet at every moment with 
examples of these very remarkable phenomena, pioiiuced 
by the simple impressions of foreign bodies on the mucous 
surfaces; I cannot deny that cheleterious substances n-ay 
act in the same way upon the nerves of the lungs, though 
we must not exaggerate the sphere of this mode of action.* 

In fact, I am not acquainted with any one example^ 
where the contact of a deleterious substance with a 
mucous membrane, has been the sudden cause of death* 
It may indeed be productive of such effect after a certain 
time, but never at the moment of its action ; neverthe- 
less, in those asphyxias which are produced by mephitic 

*\i appear? 'from the experiments of M. DeiK>rme6 that the contact 
of sulphuretted hydrogen on the .«kin of an animal is immediately fatal. 



?■ 



284 PHYSIOLOGICAL RESEARCHES 

vapour, 80 rapidly does death come on, that the black 
blood can scarcely have had the time to exert its influence 
upon the body. The principal cause of the cessation of 
the functions is manifestly the action of the pernicious 
substance. 

These considerations, then, incline me to believe, that 
these substances pass into the blood through the lungs, 
and that in circulating with the blood they carry to the 
organs the immediate cause of their death. Such passage 
into the blood has already been suspected by many phy- 
sicians ; the truth of the fact appears to be indubitably 
proved by the following reflections. 

1st, It can hardly be doubted, that the poison of the 
viper and many other venomous animals, and that the 
saliva of rabid animals, pass into the system of the blood, 
and are taken up either by the veins or the lymphatics. 

2dly, It appears to be very certain, that a portion of the 
atmospheric air is actually absorbed through the mucous 
membrane of the lungs itself, and not by means of the 
absorbent system. Now, if this be the case, I know not 
what should hinder the passage of mephitic vapour in 
the same way.* We are not sufficiently acquainted with 
the limits of the particular sensibility of the membrane 
of the air cells, to say that it cannot give a passage to 
such vapour. 

3dly, The respiration of an air which has been charged 
with the exhalations arising from oil of turpentine, com« 

* We know that fine injection» pass from the branches of the pulmo- 
nary artery into the divisions of the bronchia; and that even water, 
when pushed into the trachea, will return, at least a small quantity of 
it, by the pulmonary veins and arteries. 

Bichat thought that the gases absorbed in the lungs must pass through 
the mucous membrane ; t ut this is not the case unless absorption takes 
place at the time they are in the bronchia, for the mucous membrane 
which lines the air-tobet does not extend into each bronchial lobule. 



ON LIFE AND DEATH. 285 

municate a particular smell to the urine. It is thus that 
this fluid is affected from the residence of the persons in 
a newly varnished room. In this case it is evidently 
by the lungs in part, that the odoriferous fluid has its 
passage into the blood, and so on io the kidneys. In fact, 
I have often assured myself by breathing out of a bottle 
through a tube, air so charged (in which case it could not 
act on the cutaneous surface) that the smell of the urine 
undergoes a change. If, then, the lungs will admit a 
variety of substances, which do not enter into the compo- 
sition of respirable air, for what reason should they not 
admit the mephitic vapour of mines and subterraneous 
places. 

4thly, The respiration of humid air produces dropsy. 
The extent of the fact has been exaggerated, indeed, but 
the fact itself is true. It proves, that an aqueous fluid 
may pass into the blood, and consequently that other 
substances may pass into it also. 

5thly, If an animal be asphyxiated in sulphurated hydro- 
genous gas, and a plate of metal some time after its death 
be placed under one of its muscles, the surface of the plate 
contiguous to the muscle, will be sensibly sulphurated. 
The foreign principle, then, which is here united with 
the hydrogen, must have been introduced into the circu- 
latory torrent by the lungs, and have penetrated with the 
blood into all the parts. The deputies of the Institute 
have observed this phenomenon in their experiments. I 
have made a similar remark in asphyxiating animals with 
nitrous gas. A phenomenon of the same nature accompa- 
nies the exhibition of mercurv. 

From the above, we have nearly a right to conclude, 
that the different deleterious substances of which the gases 
are the vehicles, do actually pass into the blood, and so 
affect the organs. Of this matter, however, I shall 
adduce some further proofs. 



286 rilYSIOLOGlCAL RFiSEARCUES 

I have ascertained by a number of experiments, that 
atmospheric air, or any other aeriform fluid, may be made 
to pass into the blood without alteration. 

Divide the trachea of a dog, inject the air-cells strongly 
with common air, and continue to retain it in the lungs. 
The animal will immediately discover signs of great 
distress and agitation ; if an artery now be opened, the 
blood will be emitted in a frothy state. 

If hydrogen have been employed, it may easily be 
ascertained that the nature of the fluid is unchanged, by 
placing a candle over the bubbles which are disengaged. 

When the blood for the q>acc of thirty seconds has 
flowed in this state, the animal life of the creature will 
be finished, and death ensue, with all the symptoms which 
accompany the insu£9ation of air into the black-blooded 
system of vessels. The re-admission of air into the 
lungs, will have no efiect in restoring the animal to life, 
for as soon as frothy blood can flow from any one of the 
arteries, it must already have afiected the brain with its 
pernicious influence. 

In this case it may be perceived, that the causes of death 

ft 

are the same as those which proceed from the insufflation 
of air into a vein. In the one instance the air passes 
at once from the lungs into the arterial system. In the 
other, from the veins across the lungs and then into the 
arteries. 

When we open the bodies of animals, which have been 
killed in these experiments, the whole apparatus of the 
red-blooded vascular system, is found to be filled with air 
bubbles of various sizes. In some circumstances, the 
blood will be transmitted in the same state into the gene- 
ral capillary system, and from thence into the veins ; in 
others it will be stopped in the capillary system, and 
in such cases, though the circulation may have continued 



ON LIFE AND DEATH. 287 

for some time after the suspension of the animal life, not 
a single particle of air will be discovered in the veins. 

In these experiments which I have frequently repeated, 
I have never found that the least fissure has been made in 
the bronchise ; nevertheless, I confess that it is difficult to 
say, whether this be so in their last ramifications. The 
following phenomenon, however, may throw some light 
upon the subject ; for as often as air is pushed into the 
lungs with great violence, there will be produced an 
emphysema of the breast, or neck, from the infiltration 
of this fluid among the cellular texture, in addition to its 
passage into the blood. But if the impulse be moderate, 
and the quantity of air injected not much beyond the 
measure of a full inspiration, it will pass into the blood 
only, and not into the cellular texture.* 

* This fact, frequently confirmed in my experiments, is not always the 
same in man. V/e often see emphysema produced by violent efforts of 
respiration, efforts which have forced into the ceUalar organ the air 
contained in the lungs. Now, if the passage of the air in the blood 
preceded or even accompanied its introduction into the neighbouring 
cells of the bronchia, all these cases of emphysema would be necessarily 
fatal, and even in a sudden manner, since, from what has been said 
before, the contact of the air on the brain, to which the circulation 
would carry it, would inevitably interrupt the functions of this organ. 

Yet we see that emphysema is often cured, or does aot produce death 
for a length of time.t I saw, at the Hotel Dieu, an air tumour, suddenly 

f I saw, in a little girl of seven or eight years of age, an emphysema 
which occurred in a paroxysm of coughing, and which extended to the 
^thorax, the abdomen and the superior part of the thighs; the swelling 
of the neck was so considerable, that at the moment 1 was called 
suffocation was imminent. I made, in the skin above the sternum, an 
opening, which very quickly produced an evacuation of the air. In 
five or six days, though the hooping cough continued, this little patient 
was entirely cured of the emphysema, which had been very near' 
destroying her. It did not appear to me that the lungs had participfited 
at all in the general emphysema. 



288 PHYSIOLOGICAL RESEARCHES 

The experiments of which I have given the detail , ex- 
emplify phenomena which do not indeed take place in the 

appear in the axilla^ from the violent effortf of the patient to prevent 
respiration, whiUt Default reduced an old luxation. In a few days this 
tumour disappeared without producing any inconvenience. We find. 
In the Memoirs of the Academy of burg^ery and in Treatises on Opera- 
tions, various examples of emphysema produced by powerful agitations 
of the thorax, and in consequence of the introduction of a foreign body 
into the wind-pipe ; emphysema, with which the patients have lived 
many days, and from which even they have recovered. 

There is then no doubt, that often in man the air passes from the 
lunirs into the cellular texture, without entering the arterial system. 
My experiments on animals have not been exactly analogous to what 
happens from the introduction of a foreign body, when a part of the 
air enters and goes out. It is then probable that from a cause precisely 
similar would arise also the same effect in animals. 

And vice versa, the passage of the air in the blood-vessels sometimes 
takes place in man, without the infiltration of the cellular organ ; then 
the death is sudden. 

A fisherman, subject to colick, was suddenly seized with it in his 
boat; the abdomen swelled, the respiration became painful and the 
patient died almost instantaneously. Morgagni opened the bodj the 
next day, and found the vessels full of air. Pechlin also says he saw a 
man die suddenly in great distress and with a hurried respiration, and 
he afterwards found a large quantity of air in the heart and in the large 
vessels. -* 

I have dissected many bodies, in which, before death there had been 
a sanguineous congestion in the exterior capillary system of the face, 
the neck and even of the thorax. This system exhibited a remarkable 
engorgement and lividity in al) its parts, and 1 have found in opening 
the arteries and veins, in iho<«e of the neck and head especially, a 
frothy blood mixed with bubbles of air. I learnt that one of these 
subjects died suddenly with a convulsive affection of the pectoral 
muscles ; I have no information respecting the others. Besides, all 
who have had much to do with dissecting rooms, must have seen bodies 
of this kind, which very soon become putrid and emit an insupportable 
odour. They have observed also that the air in the vessels existed 
previous to the putrefaction. 

I suspect that in all these cases death has been produced by the 
sadden passage of air from the lungs into the blood, which bw after- 






ON LIFE AND DEATH. 2S9 

ordinary process of inspiration, and therefore I allow that 
DO very rigorous induction can be drawn from them, with 
respect to the passage of deleterious substances into the 
mass of the blood ; nevertheless it appears to me, that 
they very much confirm the probability of such fact, 
which besides is demonstrated by many of the preceding 
remarks. I shall conclude, then, that such passage is real. 
In fact, we have seen 1st, That the sole transmission of 
the black blood into the arteries, will not account for the 
infinitely various phenomena exemplified in the different 
sorts of asphyxias; 2dly, That the simple contact of the 
deleterious substance with the nerves of the lungs, can by 
no means be the cause of a death so rapid as that which 
is occasioned by these accidents; 3dly, That, therefore, 
we are forced as it were to suspect the passage of the 
poison itself into the blood ; 4thly, That a number of 
considerations are in favour of such suspicion, and thus 
that the fact is proved both directly and indirectly.* 

This principle being once established, a variety df 
results must flow from it. Of the first of these, of the 
mode of action^ namely, which the deleterious substance 

wards carried it to the brain ; nearly like what I have said takes place, 
when, in a living animal, we force much air towards the lungs, and thus 
drivd this fluid into the vascular system. 

By considering these phenomena irl connexion- with the remarks 
presented above on death from fhe injection of air into the veins, the 
•pinion 1 have advanced, will I think, be admitted, and it is besides the 
opinion of many other phy^icianf*. Many experiments have already 
been made on thé dead body relative to this point. Morgagni has 
presented them in detail ; but it is on the living (hat we must observe 
the passage of the air into the blood in order to deduce consequences 
which shall bear on the subject on. which we are treating. We know 
in fact what is the influence of death on the permeability of the parts. 

^' The above experiments explain the manner in which emphysema is 
produced from Any very violent exertion of the muscles of the chest. 

37 



« 



i 



29% PHYSIOLOGICAL RKISEARCHES 

must exercise upon the different organs, I shall say 
nothing, having nothing to offer but conjecture. 

I shall accordingly content myself with inquiring what 
system it is which is particularly influenced by these 
substances, when mingled with the blood. — Now, 1st, 
This system appears to be the nervous one, and that 
portion of it c^^pecially, which presides over the parts of 
the animal life, the organic functions being only seconda- 
rily affected ; 2dly, Of all the nervous system, the brain 
is that part which is the most affected ; 3dly, Under this 
relation Monsieur Pinel appears to me to have been right, 
in placing some of the asphyxias (those for instance which 
are occasioned by the presence of a deleterious substance) 
among the neuroses. On this head the following con- 
siderations should leave us little doubt. 

1st, In all the asphyxiœ, when the presence of a dele- 
terious substance cannot be doubted, the symptoms consist 
of two general and opposite sets of phenomena, of spasm 
and torpor. Of two workmen who had come up out of 
the sewer of the street St. André dés' Ares, the one 
sat himself down upon a bulk, and fell into a state of 
asphyxia; the other with irregular convulsive movements, 
proceeded as far as the rue Battoir, and then fell down 
asphyxiated. The Sieur Verville, in consequence of 
inhaling the breath of a maq who was lying in a state 
of asphyxia from the vapour of lead, fell down suddenly, 
and in a short time became convulsed. The vapour of 
charcoal intoxicates, as it is said. I have seen animals 
asphyxiated with other gases, and perishing with a stiff- 
ness, such as could be produced only by the most violent 
spasm. The centre of all these sy-mptoms, and the organ 
from which they emanate, undoubtedly is the brain, and 
they depend upon its irritation or eompression. 



ON LIFE AND DEATH. 291 

Sdly, The animal life is always interrupted before the 
organic life, wherever the asphyxiating cause has been of 
a compound nature. Now the centre of the animal life 
is the brain. 

3dly, I have proved when the animal perishes from 
the circulation of the black blood in the arteries, that the 
brain is especially aSected even then ; but in the same 
way, that is, by the cephalic* arteries, the deleterious sub- 
stance rtself, may be introduced into the brain. 

4thly, I have pushed a variety of deleterious gases (for 
example, sulphurated hydrogen) into the brain, and also 
some of those substances which vitiate the nature of these 
gases. The animal has always perished with symptoms 
of spasm, or torpor, ar^d in general the death which is 
occasioned by the different gases, is always similar to that 
which is produced by the introduction of pernicious sub- 
stances into the brain. 

5thly, The consequences of these asphyxias, when life 
has been restored, invariably suppose a lesion of the 
cerebral system, such consequences consist of palsy, tre- 
mour, wandering pains, aad derangements of the exterior 
apparatus of the senses. 

From all these multiform experiments and considera- 
tions, we'l&ay surely conclude, that it is on the brain and 
nervous system that the deleterious principle, introduced 
into the biood, must act; from the death of these parts, 
that of the others is derived. 

In this case the different organs no doubt are directly 
enfeebled, and may perhaps be immediately affected by 
those principles, which flow into, them together with the 
blood, but all such phenomena, are even more visible ia 
the animal, than in the organic life. 

. Let us not forget however, that a part at least of the 
cause of this sort of death, consists in the influence of the 



299 PHYSIOLOGICAL RESEARCHES 

yeoous blood upon the organs, and t(iat this influence 
must ever be in proportion to the length of time that 
such blood continues to circulate. The differences then 
which are found in the asphyxias, may be said to proceed 
from the greater or less effect of the venous blood upon 
the system, from the different nature of the various 
deleterious substances inspired, and from the age and 
temperament of the individual affected. 

IL In the greater number of diseasesif death commences 

in the lungs. 

I have just spoken of sudden death. I shall now 
enlarge a little on that which is the slow effect of disease. 
Physicians must be well persuaded, that by far the greater 
number of diseases, put an end to life by an affection of 
the lungs. Whatever be the seat of the principal affec- 
tion, be it either an organic lesion, or a general disorder 
of the system, the action of the lungs in the latter 
moments of existence, becomes embarrassed, the respira- 
tion difficult, and the oxydation of the blood, but slowly 
effected; accordingly this fluid must pass into the arteries, 
almost in the venous state. 

The organs therefore which are already enfeebled, must 
be much more readily affected by the pernicious influence 
of such blood, than those which i^re subject to it, in the 
different cases of asphyxia. In this way the loss of 
sensation, and intellect, are very shortly the effect of 
embarrassment in the lungs ; and ensue as soon as thQ 
brain begins to be penetrated with the fluid which is sa 
transmitted to it. 

By degrees the heart and all the organs of the internal 
life, cease also to move. It is here the black blood 
which arrests these vital motions, which have already 



t)N LIFE AND DEATH. f 95 

been enfeebled by the disease. Such weakness, the con- 
sequences of thé disease, is very rarely the immediate 
cause of death, it only prepares it, by rendering the 
organs more susceptible of the alteration in the healthy 
state of the blood. Such alteration is almost always the 
immediate cause of death. The disease then, is only an 
indirect cause of death in general, it kills the lungs, and 
the death of the lungs occasions that of all the other 
part5. 

From hence it may be easily conceived, why the small 
quantity of blood contained in the arterial system of the 
subject, is almost always black. For 1st, The greater 
number of deaths begin by the lungs. 2dly, We shall 
gee that those which have their commencement in the 
brain, are «qually the cause of this phenomenon. Accord- 
ingly there can be only those, in which the heart ceases 
suddenly^ to act, after which the red blood can be found 
in the aortic ventricle, and auricle. Such appearance is 
seldom found, excepting in the bodies of persons who 
have perished from extensive hemorhagy. 

From the frequency of deaths beginning with an embar- 
rassment of the lung», may be conceived also the reason, 
why this organ is so frequently, gorged with blood in the 
carcase in general, the longer the agony, the heavier 
and fuller are thie lungs. When such fulness is found, 
together with black blood in the red-blooded system, 
whatever the disease may have been^it may be pronounc- 
ed that death has begun in the lungs. In fact the con- 
catenation of the phenomena of death is from one of the 
three organs, from the lungs, brain, or hearty to all the 
others. Now when death begins in the heaft, the pulmo- 
nary vessels are generally empty, and there is red blood 
in the aortic system. On the other hand, if death have 
began in the brain, there is then indeed a certain quantity 



394 PHYSIOLOGICAL RESEARCHES 

of blood in the arteries, but the lungs are empty, unless, 
when gorged with blood, by some antece'dent affectioà* 



CHAPTER X. 

•F THE IKFLVGNCE OF THE DEATH OF THE BRAIH OVEE 

THAT OF THE LUNGS. 

As soon as the human brain ceases to act, the functions 
of the lungs are suddenly interrupted ; this phenomenon, 
which is constantly observed in the red and warm-blood- 
ed animals, can happen only in two ways. Ist, Because 
the action of the brain, is directly necessary to that of 
the lungs, or !^ly. Because the latter receives froni the 
former, an indirect influence by meant of the intercostal 
muscles and diaphragm, an influence, which ceases with 
the activity of the cerebral mass. Let us try to determine 
which of these two modes is that of nature. 

I. Is it directly that the lungs cease to act upon the 

death of the brain ? 

I shall have proved that the death of the brain, is not 
immediately the occasion of that of the lungt^ if I can 
determine that there is no immediate influence exercised 
by the first, upon the second of these organs, now, this 
essential principle may be easily demonstrated by experi- 
ment. 

The brain can exercise an immediate influence on the 
lungs, only by means of the par vag^um or the great 
sympathetic nerve, the only nerves, which according to 
the common opinion^ establish a communication between 



ON LIFE AND DEATH. 295 

the two organs (an opinion however which is erroneous, 
as the great sympathelic is only an agent of communica<- 
tion between the organs and the ganglions of the system.) 
Now 1st, The influence which is derived by the lungs 
from the par vagum, is not actually necessary for them 
to act. The following experiments will show the truth 
of this assertion. 

1st, Irritate the par vagum on one or both sides, and 
the respiration of the animal will be somewhat quickened; 
but such appearance is no proof of an immediate influ- 
ence, for any wound of the neck, or any wound whatever, 
provided that it be the occasion of considerable pain^ witl 
be the cause of a similar phenomenon. 

2dly, Cut one of the nerves, and the respiration will 
be at once affected, as when the nerve is irritated ; but 
as soon as the pain ceases, the embarrassment of the lungs 
will disappear; and ^t the end of four and twenty hours, 
the phenomena of life be concatenated with their accus- 
tomecl regularity. 

S^lly, Divide these nerves on both sides. In this case 
the breathing will be much more precipitated, and will 
not return to its ordinary state, as in the preceding experi- 
ujent ; it continues laborious for four or five days, an4 
the animal perishes.* 

* The diviaion of (he nerves of the eighth pair in the neck produces 
two kinds of effect^, tvhich should be carefulljr distinguished ; the one 
relates to the larynx and the other to the lungs. Among the first, 
aphonia is one of the most striking symptoms. We see a very good 
reason for this phenomenon, when we recollect that the recurrent nerve 
19 a branch of the eiglith pair ; but besides the Toss of voice, the division 
of the eighth pair often produces such an approximation of the edges of 
the glottis that the air cannot enter, and death immediately takes 
place. 

Most usually, the approximation is not sufficient to prevent entirely 
ihe entrance of the air into the thors^x ; but as the glottis has lost its 



296 PHY^OLOGICAL RESEARCHES 

From the two latter experiments it follows, that the 
par vagum is indeed necessary to the phenomena of 
respiration, and that the brain must exercise, of course, 
an influence over this function, but at the same time, it 
may be seen, that without tHe immediate influence of the 

motions in relation with those of respiration, this function is always 
perfurnied in a more or less incomplete manner. 

When these observations were first made» it was hardly possible to 
l^ive an accurate explanation of them ; bat since I have ascertained the 
manner in which the recurrent and laryngeal nerves are distributed to 
the muscles of the larynx, there is no longer any diiiculty. By the 
division of the eighth pair at the inferior part of the neck, the dilator 
muscles of the glottis are paralyied ; this opening doei not enlarge at 
the moment of inspiration, whilst the constrictors, which receive their 
nerves from the superior laryngeal, preserve their action entire, and shut 
more or less completely the glottis. 

When the division of the eighth pair does not close the glottis so 
oompletely as to produce death immediately, another order of phe- 
nomena is developed. 

The respiration is at first embarrassed, and its rhythm often experi- 
ences a remarkable alteration ; the inspiration is slow, and the expiration 
quick and short. The animal is averse to motion and seems to be easily 
Iktigaed. At first the formation of the arterial blood is not prevented, 
bat soon its vermilion colour changes, it becomes daricer and approxi- 
mates more and more that of the venons blood. The temperature falls, 
and the very embarrassed respiration is onl^ made by the aid of all the 
muscular powers ; the coldness becomes evident, and the animal soon 
dies. 

As this series of circumstances is developing, the animals, on whom 
the experiments are made, consume less oxygen) and form leu carbonic 
acid. 

We find, on opening the body, the bronchia filled with a frothy, and 
sometimes a bloody fluid ; the lungs are engorged, and the divisions of 
the pulmonary artery are much distended with very black blood. 

From all that has now been stated, it is natural to conclude that, in 
this last case, the animals die because respiration can no longer be 
effected, the lungs being so altered that the air cannot get into the 
bronchial cells. To this cause should be added also the difficulty which 
the blood experiences in passing from the arteries to the pulmonary 
veins. 



ONT LIFE AND DEATH. 



«97 



brain, the lungs will continue in play, and consequently 
that the interruption of such influence, as when the brain 
is injured, will not be an immediate obstacle to the con- 
tinuation of the pulmonary actions. 

The question whether the functions of the lungs are 
more immediately connected with the influence derived 
from the ganglions, may be decided by the following 
facts. 

1st, If on the one and the other side of the neck, the 
nervous thread be cut, which is usually regarded as the 
trunk of the great sympathetic, there follows little or no 
alteration in the phenomena of respii^ation. 

2dly, If the par vagum and the great sympathetic be 
divided at the same lime on both sides of the neck, the 
animal will die after a certain time, and much in the same 
way, as when only the par vaa;um is divided. 

3dly, When we divide the sympathetic nerve in the 
neck, we do not deprive the lungs of the nerves which 
come from the first thoracic ganglion ; now these nerves 
may contribute to keep up the action of the lungs, since^ 
as I have said, each ganglion is a nervous centre, capable 
of emitting its own peculiar irradiations, independently of 
the other centres, with which it communicates. 

But whether the nerves, which are derived from the 
first thoracic ganglion, do really assist the functions of 
the lungs, I have not been able to ascertain by experi- 
ments on the nerves themselves, for such is the position 
of the first thoracic ganglion in most animals, that it 
cannot be taken away without doing so much injury to 
the parts as would kill the creature, or throw it into such 
agitation, as wholly to confound the phenomena of which 
we are in search, with those of a general distress and 
trouble. From analogy, however, and from the destruc- 
tion of other ganglions, by which the internal organs are 

'38 



298 PHYSIOLOGICAL RESEARCHES 

supplied, we should not have a ri^ht to suppose that the 
lungs would cease to act, when the ganglion in question 
is destro3'ed. 

Besides, the following reasons appear to me to prove 
unquestionably, the principle which I advance. If great 
lesions of the brain have the effect of suddenly interrupt- 
ing respiration, because this orp;an can no longer influence 
the lungs by means of the nerves, which come from the 
first thoracic ganglion, it is evident that if all communica- 
tion between the brain and this ganglion be taken away, 
such influence must cease, and respiration be suspended ; 
but if we divide, as Cruikshanks has done, the spinal mar- 
row on a level with the last of the cervical vertebrae, the 
animal will continue to live and breathe for a length of 
time, notwithstanding the want of communication between 
the brain and the lungs, by means of the first thoracic 
ganglion. From the above experiments, we may con- 
clude, that the brain does not exercise any direct and 
actual influence over the lungs, and consequently that 
other causes must be sought for, if we mean to account 
for that sudden and instantaneous cessation of the func- 
tions of the latter of these organs, when those of the 
former are suspended. 

There exists, notwithstanding, a phenomenon which 
seems to cast some doubt upon the conclusion which I 
have deduced, and in the principle which it establishes. 
I speak of the sudden diffîculty of respiration, and that 
impeded circulation which are occasioned by violent pain. 
This distress appears to indicate that the heart and the 
lungs are dependent immediately upon the brain ; for the 
distress is in the brain, say the greater number of authors, 
and the affection of the heart and lungs, a consequence of 
the reaction of the brain ; but here let it be remembered, 
that almost all pain is made up, first of sensation, and 



iu 



ON LIFE AND DEATH, 299 

secondly of some emotion, passion or affection.* Now 
as I have proved at length, in the former part of this 
work, all passion and emotion have their seat in the inter- 
nal viscera, and thus it will appear, that the trouble which 
in such case is felt in the heart and lungs, does not depend 
upon the brain for its cause, but is the immediate effect 
of the passion, or emotion, which accompanies the sensa- 
tion. The following considerations will bear me out in 
this conclusion. 

1st, In many instances the dyspnoea and impeded circu- 
lation, precede the pain. Examine the thorax, and place 
your hand upon the heart of a man about to undergo an 
operation, and you will be easily convinced of this truth. 

2dly, There is sometimes a manifest disproportion be- 
tween the sensation of pain, and the distress which is 
experienced about the heart, and in breathing. 1 have 
known the operation of cutting away the prepuce imme- 
diately fatal. Now in this case, it surely could not be 
pain which killed the man. 

3dly, There are many persons who are capable of sup- 
porting violent pain, with resolution. Place your hand 
upon the heart of such persons, and no agitation whatever 
will be fell there. Nevertheless, their perception of pain 
must be what it is in other persons. 

4thly, In the course of an operation, we are not to 
judge of the patient's state of mind, from his cries, or 
silence. This sign is very deceitful ; because a man may 
be suflSciently master of himseli to overpower the influ- 

♦ These word» passion^ emotion^ afffction^ &c. have, 1 know« real 
difierences in the ianguas;e of metaphysicians ; but as the general effect 
of the sensations which they express is always the 5ame on the onçanic 
life ; as this general effect is what alone concerns me, and as the 
secondary phenomena are of no importance, I use these words indiffer- 
ently for each other. 



sou PHYSIOLOGICAL RESEARCHES 

cnce of his internal organs. We must examine the heart 
and lungs ; their functions, if I may allow myself the 
expression, are the thermometer of the affections of the 
mind, it is not without reason, that the actor who plays 
the part of a courageous man, takes hold upon the hand 
of him whom he wishes to set at ease, and lavs it on his 
heart. The exterior movements of the passions, are not a 
fair criterion of the inward feelings of the individual, for 
these movements may he feigned as well as real : feigned 
if they originate in the brain : real if they have their 
sources in the heart ; — in the first case voluntary, in the 
second involuntary. Touch the pulse of the angry man, 
if you wish to know whether he really is in anger. 
When I see a woman weeping or convulsed at any dis- 
tressing news, and find her pulse in its natural state, I 
know what to judge of her affliction. — On the contrary, 
if her grief be concentrated, but her heart beat strongly, 
or her pulse have been suddenly depressed, I know that 
she feigns a calm which she does not feel. To judge , 
correctly, we must always compare the external move- 
ment with the state of the internal organs. There could 
be no deceit, were it possible to distinguish the involun- 
tary movements produced in a state of passion, by the 
action of the heart upon tiie brain, and then by the reac- 
tion of the brain upon the muscles, from the voluntary 
movements which are occasioned by the simple action of 
the brain upon the locomotive system. 

However strong may be the pain which has been the 
occasion of the dyspnoea, and impeded circulation, of 
Tvhich we have been speaking, this dyspnoea and distress 
about the precordia, will cease, provided only that the 
pain be continued. Nevertheless, if the reaction of the 
brain were the real cause of the distress in question, 
the coQtrary should be the case ; for the continuation of 



ON LIFE AND DÈATlT. 301 

the affection of the hrain, should continue also to cause 
its re-action. But here the effect of hahit is evident, 
though the pain subsists ; the brain indeed continues to 
be affected, but the internal organs cease to be so. It 
may be easily perceived, that I am not here speaking of 
those cases, where the action of the heart and lungs has 
been deeply troubled by the effect of pain. 

To the above considerations I might add many others, 
with the view of proving, 1st, That although the brain 
be the seat of the pain, it is not the source of those affec- 
tions of the internal organs, which are occasioned by 
such pain ; 2dly, That these affections depend upon an 
emotion, which is absolutely distinct from sensation of 
whatever kind, both in its nature and effects. 

II. Is it indirectly that the lungs cease to act upon the 

death of the brain. 

• 

Since the death of the lungs, upon the cessation of the 
cerebral action, is not direct, there must exist between 
the brain and the lungs, some intermediate agents, the 
cessation of whose functions, occasion the cessation of 
those of the lungs. These agents are the diaphragm, and 
intercostal muscles ; for they depend immediately upon 
the brain by means of the nerves, which they receive from 
it, and consequently become paralytic on the death of the 
brain ; the following experiments are a proof of the fact.* 

*We have said in a preceding note, that the division of the nerves 
of the eighth pair could produce dedth in two ways ; first, hy closing 
the glottis, and preventing the entrance of the air into the air tubes; 
secondly, by altering the lungs and preventing the production of the 
chemical phenomena. Of these two kinds of death the Cr«t is in some 
measure accidental ; it is an indirect efi!*ect of the interruption of the 
action of the brain; but it is not so with the* second, and though it may 
not be instantaneous, it is not kss a direct eHVct o( the division. It 



M2 PHYSIOLOGICAL RESEARCHES 

Isty Cruikshanks divided the spinal marrow of a dog 
between the last cervical, and the first dorsal vertebrae. 
The intercostal muscles accordingly were immediately 
paralyzed, and the breathing of the animal continued to 
be made by the diaphragm only, which receives the 
phrenic nerve from a point above the section. In this 
experiment, it is easy to judge of the strong action of the 
diaphragm, by that of the abdominal musoles. 

2dly, If the phrenic nerves only be divided, the dia- 
phragm becomes immoveable, and then the respiiration of 
the animal is effected by the intercostal muscles only. 

3dly, After the two preceding experiments, the animal 
will live for a considerable time, but if the phrenic nerves, 
and the spinal marrow, towards the end of the neck, be 
divided at the same time, or what comes to the same 
thing, if the spinal marrow be cut above the origin of the 
phrenic nerves, then all communication between the brain 
and the active agents of respiration is cut off, and death 
follows of course. 

4thly, I have frequently observed, that half an inch of 
difference in the place where the spinal marrow is divided, 
produces such a différence in itè consequences, that in the 
one case the death is sudden, and supervenes in the other 
only, after an interval of fifteen or twenty hours. In 
dissecting the carcases of animals killed in this manner, 

might be supposed that the motions of the glottis being destroyed, and 
the entrance of the air being rendered conséquent]/ more difficult, that 
it is in consequence of this obstruction that respiration is embarrassed, 
and that the alteration of the lungs is only a consecutive phenomenon. 
But in the experiments made by M. Dupuy at A 1 fort, a free passage was 
given to the air, by an opening made in the trachea. Now it cannot 
bo believed that the small wound necessary for this opening, could 
contribute to produce the disturbance of the respiration, for a similar 
operation, is daily performe'd on horses, without producing the slightest 
incoDveDience. 



ON LIFE AND DEATH. 308 

I have constantly observed that the difference depended 
always upon the circumstance, of the phrenic nerve being 
cut or not. 

From these experiments then it is evident, that respira- 
tion ceases on a sudden, and in the following manner, in 
all lesions of that part of the nervous system, which is 
placed above the origin of the phrenic nerves. 1st, 
There is an interruption of action in the voluntar}^ nerves, 
which are placed below the point of lesion, and conse- 
quently in the phrenic and intercostal nerves. 2dly, A 
paralysis of almost all the muscles of the animal life, and 
particularly of the diaphragm and intercostal muscles. 
3dly,- A cessation of the mechanical phenomena of respi- 
ration. 4thly, A suspension of the chemical phenomena 
of respiration. The interruption of all these movements, 
is as rapid as their concatenation is prompt, in the natural 
order. 

It is thus that those persons perish, who experience any 
great lesion of the spinal marrow, between the brain and 
the origin of the phrenic nerves. . Physicians have been 
very much embarrassed, in fixing with precision the spot, 
when a wound of the medulla ceases to be mortal ; from 
what I have advanced, the limit is easily assigned.* From 
the same causes, concussion, and compression of the brain, 
are also fatal. 

We should observe notwithstanding, that these different 
causes of death, may act with various degrees of intensity. 
If they acï but feebly, they affect the intellectual func- 
tions only, for these functions are always the first to be 
altered, in all lesions of the brain however small. If the 
lesion be greater, the affection extends to the muscles of 
the limbs, and convulsion or palsy ensue. Lastly, if the 

* The experirnents of Legalloi;» have clearly proved, that this point is 
at the origin of the nerves of the eighth pair. 



304 PHYSIOLOGICAL RESEARCHES 

lésion be very fcresLt^ the whole of the muscles of the 
animal life, the intercostals and diaphragm, as well as 
the others, are paralyzed, and death follows. 

We now can reply to the question proposed at the 
beginning of this section, and affirm that the death of 
the lungs is occasioned indirectly, by the death of the 
brain. 

It follows also, from the principles which are above 
established, that respiration is a mixed function, a func- 
tion placed as it were between the two lives, to which it 
serves as a point of contact, belonging to the animal life 
by its mechanical functions, and to the organic life, by its 
chemical functions ; and hence we have the reason no 
doubt, why the existence of the lungs is as much connect- 
ed with that of the brain, as with that o( the heart. 

It may be observed in the series of animals, that in 
proportion as the organization of the brain is straitened, 
a number of the phenomena of respiration also are lost. 
In birds, and the mammalia, this function as well as the 
brain, is much more developed than it is in the classes of 
fish and reptiles. It is known, that the nervous system 
of those animals which breathe by tracheae, is less perfect 
than in those which breathe by lungs ; and that in those, 
where there is no nervous system, that of respiration 
disappears also. 

In general, there is a reciprocal relation between the 
brain and the lungs, especially in birds and the mammalia. 
The first of these occasions the action of the second, by 
raising the ribs and favouring the entrance of air into the 
bronchiae ; the second also keeps up the activity of the 
first, by means of the red blood which it sends thither. 

It would be an interesting speculation to inquire into 
the relation of the nervous system with that of respira- 
tion in the class of insects, for as they receive the air 



ON LIFE AND DEATH. 305 

by points, which open externally, there «eems to be no 
mechanical action in the process of their breathing, and 
thus the function appears with them to belong entirely to 
the organic life, 



CHAPTER XL 

ey THE INFLUENCE OP THE DEATH OP THE BRAIN OYER 

THAT OP THE HEART. 

In the preceding chapter we have shewn how the lungs 
remain inactive, when the brain ceases to act. — The same 
phenomenon, under the same circumstances, takes place 
also in the heart, and must happen either immediately or 
mediately. 

I. Does the Heart cease to act immediately in conse* 
quence of the interruption of the cerebral action 7 

The greater number of medical men, speak in much 
too vague a manner of the cerebral influence. They 
do not su£Sciently determine its extent and limits, with 
respect to the difierent organs of the system. 

It is evident that we shall have answered the question 

proposed at the head of this section, if we can determine 

what the influence of the brain is with regard to the heart. 

Now, we have every reason to suppose, that no direct 

influence is exercised by the former over the latter of 

these organs, which, on the contrary, is immediately 

dependent with regard to its operations, on the movement 

communicated to it by the blood. This assertion is by 

no means a new one. It has been admitted by all soond 

39 



-c ' • ' . 'l^ 



30e PHYSIOLOGICAL HESEARCHFi) 

physiologists; but as many opinions in medicine are 
founded upon a contrary principle, it will not be amiss to 
dwell upon it a little. It is equally demonstrated both 
by observation and experiment — and to begin with the 
former : 

1st, All violent irritation made upon the brain', pro- 
duces either partial, or general convulsion in the muscles 
of the animal life. Examine those of the organic life, 
on the contrary, and little will be found amiss in their 
actions. 

2dly, All compression of the cerebral mass, whether 
made by pus, water or blood, has ordinarily the effect of 
paralyzing the voluntary muscles y but so long as the 
affection does not extend to the muscles of the breast, the 
action of the heart is in no degree diminished. 

3dly, Opium and wine, «when taken in a certain quan- 
tity, diminish the cerebral energy for the moment and 
render the brain unfit for the functions of the animal life. 
The action of the heart, on the contrary, is increased. * 

4thly, In palpitation, and the different irregular move- 
ments of the heart, it is not observable that the principle 
of these derangements exists in the brain. — In this respect, 
as well as on the subject of syncope, Cullen has been 
mistaken. The brain during such time^ continues in 
action as usual. 

5thly, The numerous phenomena of apoplexy, and 
epilepsy, and concussion, &c. do certainly all of them tend 
to shew, how independent the heart is of the brain. 

6thiy, Every organ which is subject to the direct influ- 
ence of the brain, is for that very reason an organ of 
volition. Now, I should suppose, that few persons of the 
present day, would be inclined to maintain with Stahl, 
that the heart is among the number of such organs. 
What would life be^ were we able at will, to suspend the 



»«. 



i^"^ 



.Et 



ON LIFE AND DEATH. 3g7 

action of the organ, by which the system is animated ? 
From simple observation, then, we might conclude, that 
it is not immediately that the heart ceases to act, when 
the functions of the brain are interrupted, but this funda- 
mental datum of physiology and pathology, we shall 
further establish, upon actual ejcperimeut. 

1st, If the brain of an animal be exposed, and irritated 
either with mechanical or chemical agents, a variety of 
alterations will, indeed, be prociuced in the organs of the 
animal life, but none in the heart, so long as the muscles 
of the breast continue to perform their functions. 

2dly, Experiments made in the same manner upon the 
spinal marrow of the neck, present the same results. 

3dly, If the eighth pair of nerves be irritated, the 
movements of the heart will not be accelerated ; they will 
not be arrested if these two nerves be divided. In all 
these experiments, however, we must be careful to make 
a proper distinction between the emotions and passions 
of the animal, and what it really suffei^ from the experi- 
ment. 

4thly, The nature of the great sympathetic nerve, I 
suppose to be known ;* now if the same experiments be 

* Pbyeiologists baye paid much attention to the great sympathetic 
serve. They have made, in relation to its uses, many conjectures but 
few experiments ; so that we have not on this subject any very precise 
notions. The deep situation of the ganglions renders them almost 
inaccessible, the superior cervical is almost the only one that can be 
taken out without producing death. M. Dapuy, Professor of the 
Veterinary School at Alfort, has discovered a method by which he can 
remove them with ease. We shall now relate some of his observations. 

^* Iti Experiment. The lirst experiment was made on a young and 
vigorous horse, who had been treated for the glanders ; it soon appeared 
that he was not affected with it, and that it was merely the caries of a 
tooth that had led to the belief of the existence of the disease. 

^^ On the 24th of June his left guttural ganglion was extirpat- 
ed. Soon after the operation, the eye of tbc^ side appeared to be 






308 PHYSIOLOGICAL RESEARCHES 

made on the cardiac branches of this nerve, as were juade 
upon the eighth pair, the same results will follow. 

more lunk in its socket, the eyelids were swelled aod the papil con- 
tracted. 

*^ On the 28th of Jane the rub lingual ganglion appeared swollen, 
bard and attached; a discharge of fetid, greyish matter was discovered 
in the nostril of th« tame side. 

*^ On the S9th of June, the wonnd sappnrated copiously. 

*^ From the 90th of June till the 16th of July the wound advanced 
rapidly towards cicatrization. 

^* From the lOth of July to the 15th of August the animal continued 
in the same state of health. 

**On tlM l&th of August, the right gnttucal ganglion with a portion of 
the nerfe was removed; this operation was followed by the tame 
phenomena as the preceding, with thi« difTerence, that two days after 
the animal could not swallow water, it run out at the nostrils. There 
was in fact a communication between the nostrils and mouth from the 
caries of the back molar tooth, the root» of which were opposite the 
maxillary sinus, that had an opening into the nostril ; the voice was loaf. 

^^ On the 20th of August, he was much emaciated, with the skin dry 
and adherent ; the cheeks, below the jaw, were constantly moistened 
with sweat, which bad been ob^prved for twelve or fifteen days. The 
wound of the right side remained fistulous ; the skin was covered with 
scurf, the sheath and scrotum, as well as the hind legs, were oedematous ; 
the animal died. Nothing remarkable was discovered on dissection. 
Below the sub-occipital foramen the great sympathetic was slightly 
swelled, in the form of a knot, in the place where the division bad been 
■lade." 

^^ 9d Experiment. On Uie 26th of April, the right guttural ganglion, 
with a portion of the nerve, was removed from a sound horse, four and 
a half years old, strong and in good condition. The ganglion of the 
left side was first a little mutilated, and the nerve was removed poste- 
riorly to the extent of thirty three centimetres. The animal did not 
manifest so much pain as might have been expected. 

^^ The conjunctiva soon became red and the eyelids partly covered 
the eyes ; the respiration became painful and loud ; the pulse was hard, 
strong and frequent. The animal refused all food, and drank with 
great difficulty. 

<«Tbis state continued till the lOth of May following. The two 
wounds were almost healed ; the animal eat and drank well ; but the 



ON LIFE AND DEATH. 309 

I de not offer in detail the whole of these experiments ; 
the greater part of them are well known : I was induced 
to repeat them, as authors are not agreed upon their con- 
sequences. 

The experiments of galvanism, are well calculated to 
throw light upon the relations existing between the heart 
and the brain ; these I have taken care to repeat with 
the utmost exactness, and whatever authors may havo 
advanced, they are all in favour of the above opinions — 
for 1st, If the galvanic apparatus be applied to the brain, 
and to the heart, and inferior extremities of a frog, and 
the communication made between the metals, there will 
constantly be seen a strong contraction in the muscles of 
the limb, and little or none in the heart. The same will 
foe the case, to whatever voluntary muscle the zihc be 

bind legs UDd scrotam were still so much swollen as to interfere with 
lus walking ; the conjunctiva remained red and the pupil contracted. 

*^ Towards the 13th of May the skin became adherent and covered 
with scurf; the cataneous respiration wa^ nearly destroyed. 

^^ On the S5th of May, the swelling of the legs and the scrotam 
became considerable, notwithstanding the frictions with water and 
turpentine, which were made several times a day since the 13th ; he 
could, with difficulty be got out of the stable to be examined. The 
pulse retained its hardness and frequency. The dung was hard, black 
and small. 

^* Daring the month of June the phenomena were similar to those we 
have enumerated ; the swelling of the scrotum and the legs resisted the 
tonic and stimulating applications. 

On examining the body, (he ends of the nerves that bad been drawn 
out were found swollen as in the first horse. Similar results have been 
obtained in all the other experiments that have been made on this 
subjecL it may be said in conclusion, that the phenomena which 
appear after the removal of this ganglion, and which do not depend on 
the operation, are the contraction of the pupil, the redness of the 
conjunctiva, general emaciation, accompanied with swelKng of the legs, 
and a icariy eruption which ultimately affbcts the whole cutaneom 
aorface. 



310 PHYSIOLOGICAL RESEARCHES 

applied. 2dly, The same results will be had, on the 
oommunication being made between the metals applied 
on the one hand to the spinal marrow above the giving 
off of the sympathetic, and on the other hand to the heart, 
and any of the voluntary muscles. 

3dly, On establishing a communication between the 
metals applied to the cardiac nerves, and to thé heart of 
the animal, there has been no contraction in the heart. 
In ail these essays, the natural disposition between the 
parts which serve to unite the two organs, is preserved : 
there are other experiments which consist in detaching 
the heart from the breast. 2dly, In placing two points of 
its surface in contact with two different metals. 3dly, In 
making the communication between them with a third. 
From thise xperiment, Humboldt and other philosophers 
have procured contractions, but I have taken care to 
repeat it with the greatest accuracy, and must assert, 
that I have seen little or nothing of the kind ; indeed, 
if I had, I should have concluded nothing from itj 
for it appears to me, that to decide upon the influence 
of the brain over the heart, a portion at least of the 
nervous system, should be in contact with one of the 
metals. 

I shall now pass to my experiments on red and warm- 
blooded animals. They are necessary for the decision of 
the question before us, as the mode of contiractility in 
these animals differs much from that of the animals sub^ 
mitted to the experiments already mentioned. 

1st, In the winter of the year 1798, I was authorzied 
to make different essays on the bodies of persons who 
had been guillotined. I had them at my disposal thirty 
or forty minutes after they had undergone the punishment. 
In some of them, all mobility was extinct ; in others, 
this property could be reanimated in all the muscles by 






ON LIFE AND DEATH. 311 

tfie common agents, and in those of the animal life, by 
galvanism especially.* Notwithstanding which, 1 could 
never occasion the least motion, in applying the apparatus 



* Galvanic experiments have at different tiroes been made on the 
bodies of those who have been executed* Vassali, Julio and Rossi 
made a §preat number of them at Turin ; but the piles that were then 
used were very weak compared with thore that are now employed. In 
the experiments made at Newgate on the body of a criminal, the limbs 
were violently agitated, the eyes opened and shut, the mouth and the 
jaws moved in every direction, and the face was thrown into the most 
frightful convulsions. The last and most complete experiments, that 
we know of, were made at Glasgow in November 1818 by Dr. Andrew 
Ure. He used for these experiments a battery composed of two hundred 
and seventy pair of plates four inches square, with communicating wires, 
and so arranged that they could be insulated for the purpose of applying 
the electricity in a more convenient manner. 

The subject, on whom these experiments were made, was of middle 
heighth, about thirty years of age and of an athletic constitution. He 
was on the gallows almost an hour, and he was not convulsed after 
being hung, whilst a robber executed at the same time was violently 
agitated for a considerable time. He was carried to the anatomical 
theatre of the university, about ten minutes after he was removed from 
the gallows. His face bad a perfectly kiatural appearance being neither 
livid nor swollen, and the neck was not dislocated. 

About five minutes before the arrival of the .police officers with the 
body, the battery was charged with diluted nitro-sulphuric acid, which 
quickly put it in a state to exert an intense action. 

If/ Experiment, A large incision was made immediately below the 
occiput. The posterior half of the first vertebra was then removed and 
the spinal marrow laid bare, at the same time a considerable incision 
was made in the great glutaeus muscle, in order to expose the sciatic 
nerve. A slight incision was made in the heel ; no blood escaped from 
any part. A wire which communicated with one extremity of the 
battery was put in contact with the spinal marrow, whilst the other was 
applied to the sciatic nerve. All the muscles of the body were in an 
instant agitated with convulsive motions which resembled a violent 
shuddering. The strongest convulsions were on the left side ; at each 
time of renewing the electric contact by moving the second wire from 
the haunch to the heel the knee being previously bent, the leg w*s 



31S PHYSIOLOGICAL RESEAKCHES 

either to the spinal marrow and the heart, or to this 
latter organ and the nerveti which it receives from the 

thrown out with to much force, that it threw down one of the assittants 
who in Tain endeavoured to prevent the extension. 

ftd Experipunt. The left phrenic nerve was laid bare towards the 
external edge of the stemo'thjroideos ranscle, three or four inches above 
the clavicle ; as this nerve toes to the diaphrafcm, and as it commani- 
eates with the heart by the eighth pair, it was expected, that by throw- 
ing the galvanic fluid through it, the action of respiration would be 
renewed. In consequence a small incision havini; been made under 
the cartilage of the seventh rib, the point of an Insulated wire was 
placed in contact with the diaphragm, whilst the other was applied to 
the phrenic nerve of the neck. This muscle, the principal agent of 
respiration, contracted immediately, but with less force than was 
expected. As I knew by numerous experiments that we could produce 
the most powerful effects from the galvanic flnid, by leaving the extreme 
communicating wires perfectly in contact with the parts on which we 
wished to operate, whilst, in order to complete the electric chain, 
we carried the end of the wires the length of the plates, into the last 
trough of one of the poles and immediately plunged the other wire into 
the last cell of the opposite side. I had recourse to this measure Yvithout 
loss of time. The success was truly astonishing ; instantly commenced 
a strong and laborious respiration. The chest rose and fell ; the 
abdomen was pushed forward and then flattened, and the diaphragm 
contracted and relaxed. All these motions appeared without interrup- 
tion as long as I continued the electric excitement. 

In the opinion of many scientific persons who were witnesses of this 
scene, this experiment was perhaps the most striking that had ever 
been made with an electrical apparatus. It should be recollected that 
during half an heur at least, before this, thé body had been neariy 
exhausted of blood and the spinal marrow had been much lacerated. 

No pulsation could be perceived either in the heart or at ihe wrist. 

2d Experiment, The suborbiiar nerve was laid bare at its exit from 
the suborbitar foramen. One of the conducting wires was applied to 
the nerve and the other to the heel ; the most extraordinary grimaces 
nvere produced. All the muscles were put simultaneously in action in 
B frightful manner ; rage, horrour, devpair, anguish and frightful smiles 
united their hideous expression in the face of the assassin. At the 
sight of this, many of the spectators were obliged to leave the room 
and one of them fainted. 

4^A Experiment, The last galvanic experiment was made by trans- 



%." 



O^ tIFE AND DEATH. 313 

ganglions of the sympathetic, or the par vagum. Never- 
theless, the common mechanical excitant, immediately 
applied to the fleshy fibre, occasioned its contraction. 
Could this have happened in consequence of the separation 
of the nervous fillets from the brain ? assuredly not ; 
because the voluntary musclcfti were equally separated 
from it, and yet affected strongly. If any doubt remain^ 
the following experiments wiM clear it up. 

2dly, In dogs and guinea pigs, I have repeatedly appli- 
ed the metals, first to the brain and the heart, then to the 
trunk of the spinal marrow, and the heart ; then to the par 
vagum and the heart. Tht> communication being made, 
was followed by no^ apparent result. 

Sdly, On niaking the conimitnication between the 
metals, when applied to the cardiac nerves and the heart, 
there was no very sensible motion. 

4thly, Humboldt has asserted, that When the heart is 
speedily detached with some of its nervous threads about 
it, a contraction may be excited, by arming the nerves 
with a metal, and then by touching this metal with another. 
I have tnany times tried this experiment in vain. I con- 
fess, however, that once it appeaï'ed to me to succeed. 

5thly, On the contrary, I have almost always succeed- 
ed in producing contractions in the heart, by cutting 
it away from the breast, arid making a communication 
between a couple of metals, applied to different points of 



I » • 



mittJDg the electric âuid.from the spinal marrow to the cubital iierve near 
the elbow ; the fine;er8 moved qoickly like those of a performer on a 
Yiolin ; one of the assistantf who endeavoured to keep the hand «hot, 
found that it opened in spite of his^effortsi. A wire was applied to a slight 
jtocision made at the «qd of the first finger ; the hand had been prerioasly 
shut ; the finger was initantlj extended, and^ after a convulsive agitation 
of the arm, the dead man seemed to point his finger at the spectators, 
some of whom thought thalt he had come to life. 
An hour was consomed in these experiments. 
40 









314 



FHTSIOLOGICAL REiSEARCHES 



iU surface. TbiS| if I am not mistaken» is the only means 
of evidently producing the phenomena of galvanism in 
this oriraoy but with respect to our present question, the 
experiment is wholly inconclusive. 

All these eipertments I have repeated many times, and 
with the most scrupulous precautions, nevertheless I do 
not pretend to call in question the reality of those results, 
which other physicians have remarked. It is well known 
bow very variable those experiments are, which have the 
vital powers for their objeoL - Besides, in adtpitting even 
these different results, I do not see how it is possible to 
refuse acknowledging, that with respect to the stimulus 
of galvanism, there is a wide difference between the 
•usceptibility of the muscles of the animal life, and those 
of the organic life. Again, supposing that the galvanic 
phenomena were the same in both sorts of muscles,^ the 
fact would prove nothing more, than that these phenomena 
with regard to their succession, follow laws directly the 
contrary of those, which are displayed in the phenomena 
which take place, when any common cause of irritation 
is applied to the nerves and their corresponding muscles. 

The proofs adduced, will allow ut to conclude, that the 
brain exercises no direct influence over the heart, and 
consequently, that when it ceases to act, the functions of 
the latter must be interrupted indirectly. 

II. In case of lesion of the hrain^ is the death of the 
heart occasioned by that of any intermediate organ ? 



When the brain dies, the heart dies, but not directly. 
There must be some intermediate organ then, the death 
of which occasions that of the heart.* That intermediala 

*It if sbewo bj the beaatifal experiments of M. Leg;al]oi8, that the 
heart dsrircf the principle of itt forces from tba tpinai nrarrow, and 



ON UFE AND DEATH. 814 

organ is the lungs. In thra sort of death, the following 
is the series of the phenomena which may be observed. 

1st, The cerebral action' is interrupted. 2dly, The 
action of all the muscles of the animal life, and conse- 
quently of the interCostals a Ad diaphragm, is annihilated. 
Sdiy, The mechanical fonctions of the lungs are suspend- 
ed. 4th ly. The like ensues with respect to their chemical 
functions. 5tbly, The fibres of iKe heart are penetrated 
with black bloods 6thly, The fibres when so penetrated, 
die. 

Such sort of death then, has rnuch resemblance with that 
which is occasioned by the different asphyxiae. It is only 
more sudden, and that for reasons which I shall presently 
point out. The following experimehts are an evident 

from the tvhole spinal marfow, since the destruction of one of its three 
portions can àrr&st completely the circulation. The destruction of the 
Rpinal marrow does not entirely annihilate the motions of the heart ; 
but it weakens them sufficiently to prevent the circulation, and thit 
weakening is so much the greater, as the portion of spinal marrow 
destroyed i» larger. It may be presumed from this, that notwithstand- 
ing the weakening which follows the removal of a part of this marrow, 
the circulation may still contmtte if we lessen the sum of the forces 
which tlie heart must expend to maintain it. For this it is only neces- 
sary to diminish by ligaturés on the arteries, the extent of the circle to 
which the heart di«rributes the blood. This conjecture is confirmed by 
etperimeht It has been seen, for example, tBat tbe destruction of the 
marrow whiclvis very suddenly fatal in full grown rabbits, ceases to be 
so, if before doing it the abdominal aorta is tied l>etween the coeliac 
and the superior mesentric arteries. The application of the -same 
principle to other parts of tbe body leadst to a still more surpriising result, 
it is this, that in order to support life in rabbits of a certain age, after 
having destroyed the cervical marrow, it is necessary first to cut off the 
bead. They will be completely dead iV fhe marrow be destroyed before 
they are decapitated ; this arises frooklbe -fact, that by>^ttiBf off tbe 
||ead all this part is taken out of the domain of the circulation, and 
âiat by it the heart having need of less force to' continue its (bnction, 
we can weaken it by the destnn;tion of the cervfcal marrow without 
itt ceasing to perform it« 



•■k 



\ 



3ie PHT310UX31GAL RESEARCHES 

proof that the pbeDomeoi take plaee as I have described 
them to do* 

Isty I have always fouad black blood in the red-blooded 
system of all aoi mais, killed bycoocussion or compression 
of the brain ; the heart livid, and the different surfaces 
coloured as in asphyxia* 

^dly, I opened the carotid artery of a dog ; the red 
blood instantly gushed put, but was immediately suppress* 
ed, and the artery tied. I then killed the creature, by- 
striking him with violence on the occipital bone.* The 
animal life, and consequently both the mechanical and 
chemical functions of the lungs, were suddenly suppressed* 
The artery was then united. It poured forth the black 
blood with a feeble jet, for some little time, and after some 
minutes, the heart entirely ceased to move. 

ddly, I have always obtained a similar result in open- 
ing the arteries of different animals which 1 afterwards 
killed, either by dividing the marrow between the first 
vertebra and occiput, or by strongly compressing the 
brain, which I had previously ejcposed. — It is thus also 
that animals perish, by the carotids of vwhich a deleterious 
substance has been injected. 

4thly, The preceding experiments explain the reason 
why the blood is black which flows from the arteries of 
animals, which are bled in our sfaughter-houses, after 
having been knocked in the head. If the blow has been 
violent, the blood issues such as it W2[s in the veins, but 
if the action of the . diaphragm and intercostals has only 
been weakened by the blow., the redness of the blood is 

only diminished. 

-. . • 

* When an ammal is thus struck, it is not certain that the concussion 
has not extended its effects upon a greater or less part of the spinal 
marrow ; and it is not known consequently if the motions, of the bea/t 
would not cease, even when asphyxia might be prevented bj means of 
artificial respiration. 



ON EIFE AND 0]i>ATH. ' i 317 

The ftaté in vrhkh the respiration may be (and it is 
altered froa» i variety of circumstances during . profose 
hemorrhagy) oceasioas a great yariety in the colour of the 
arterial blood: hencer' we hsTe the reason why it is found 
of so many different shades in the great of>entions of 
surgery. At the beginning of these, it often flows out 
quite red; at the end of them, Js sometimes almost black. 
The easy or embarrassed state of the respiration of the 
patient, is the occasion of these varieties. This I have 
frequently remarked, when attending Desàult, and was 
often struck with the appearance, before I knew the cause 
of it. ' 

I have never found any relation whatever, between the 
obscure colour of the bbod, and the compression exercis- 
ed above the artery, as some have asserted to take place. 
There is, indeed, a conneetion between the colour and 
the impetuosity of the jet, but the reason of this is evident 
to any one who has read the foregoing pages. 

To return to the point of doctrine on which we are at 
present occupied, I* am persuaded from the considerations 
and experiments which are adduced in the course of this 
chapter, that Ihe manner in which the heart ceases to act, 
when the cerebral functions are suspended, can no longer 
admit of a doubt, and that we may resolve the qi^stion 
proposed, in affirming that under such circumstances, the 
death of the heart is occasioned through the medium of 
that of thé lungs. 

There is this difference, then^ between die death of the 
heart,^ in consequenee of that of the brain, and the death 
of ihe brain in consequence of that of the heart, that the 
one is indirect, the other -direct, as we have already seen. 
If some men i as Stahl asserts, have really been able to 
suspend the movements of the heart, the fact is not a 
proof of the influence o( the mind over the muscles of the 



313 PHT810JL06ICAL RESEARCHilS 

organic life, but of its power over the mechanical^ and 
consequently 9 the chemkal phenomena of respiration. 

In red and cold-blooded animals, the deadi of the heart 
does not succeed the deatli of the brain so quiekly as it 
does in red and warm-blooded animab. Cutoff the head 
of a frog, and the heart will continue to beat ibr some time 
afterwards. This phenomenon will be easily accounted 
for, if we recollect that respiration with these animals 
may be suspended a length of time, without arresting -the 
movements of the heart. 

In fact, as the heart dies only because the lungpi die in 
the first place, when the cerebral functions are interrupted, 
it is plain that there ought to exist between the violent 
death of the heart and that of the brain, an interval nearly 
equal to that during which, in the natural state> there may 
be a suspension of req)iration. 



CHAPTER XII. 

or THE INFLUSNCE OF T^X DEATH, OF THE BRAIN OVEH 

THAT OF ALL THE, ORGANS. 

When the brain dies, the animal life dies^ for the 
functions of this life, either directly or indirectly,? have 
their seat in the brain. It is manifest, that all the opera- 
tions and affections of the mind, together with sensation, 
locomotion, and the voice, must be put an end to in such 
case. The difficulty then respects the functions of the 
organic life. 



ON LIFE AND DEATH. 319 



I. h the interruption of the functions of the organic 
life a direct consequence of the cessation of the 
cerebral actions ? 



We shall here adduee both observation and experiment 
to prove, that the internal functions are all of them, as well 
as the action of the he|irt, withdrawn from the immediate 
ioffluence of the brain. 

1st, There are a number of diseases affecting the brain, 
which occasion so general a suspension of the animal life, 
as to leav^ neither sensation nor voluntary motion, except- 
ing some feeble oscillations of the intercostals and the 
diaphragm. In this state the individual has lost the half 
of his existence, but the one half composed of the organic 
functions, continues in the meanwhile to subsist, and in 
many cases with energy. This phenomenon is exempli- 
fied continually in apoplexy, in concussion of the brain, 
and extravasation of blood upon its sur&ce. 

2dly) During sleep the secretions certainly go on, 
though Bordeu insists upon the contrary opinion, with 
the view of proving the influence of the nerves over the 
glands. During a state of sleep, digestion goes on as 
usually it docs. The exhalations of the body are made 
with perfect freedom, and often augmented beyond their 
natural quantity ; the process of nutrition continues to 
be effected, and is probably under such circumstances, 
{ncreaseâ. There are many proofs in favor of this opin- 
ion ; but a state of sleep is a state of collapse in the brain. 
Then, neither is tl^e relaxation of the functions of the 
interinal organs the consequence of a relaxation of action 
in the brain, nor the death of the former the immediat<ft 
effect of the death of the Ijitter. 



320 rHVflOLOGICAL RESEARCHES 

3dly, The sleep of animals, which pass a certain part 
of the year in a stale of torpor, is a very strong proof of 
the co-existence of a suspension of the cerebral fonctions, 
with a permanent action of those of the organic life.*' 

4thly, In the different palsies ; in those for instance 
which affect the lower limbs, and the yiscera of the pelvis, 
in consequence of sonfie concussion or compression ef the 
medulla spinalis, the communication ef the paralyzed 
parts with the brain, is either entirely cut off, or only 
enfeebled. It is entirely interrupted when alt feeling and 
power of moving have ceased — it is enfeebled; when the 
one and the other of these properties are only enfbebled. 
But in these two cases the general and the eepillary circu- 
lations contifiue. The exhalations from the cutaneous 
mrÙEO% and in the cellular sub^tance^ are made as usual ; 
die process of absorption goes on, ibr withont absorption, 
we should soon see dropsy. The secretions also are 
effected, for nothing in such sort of 'palsy is more common 
than a copious secretion of mucus from the bladder. As 
for nutrition if it be diminished' in energy, the process is 
certainly never entirely arrested. 

5thly, Spasms and convulsions, which proceed from an 
unnatural energy of the cerebral action, have little influ- 
ence over the exhalation, secretion, and nutrition of the 

* When two states, wbich ^re not perfectly similar, are designated 
by a common name, it is ver^' difficult, whatever care may be taken to 
distinguish them, not fo apply to one ' somethioç which exclufitely 
belongs fo the other. This is perhaps ofae of the most frequent sources 
of our errour?. In this case, for example, U docs not seem that there 
is a great ineonvenienee in designating by- the word sleep' the state of 
torpor of certain animals during a part of the year. It is well known 
that we understand by it altogether a different thing from the fleep, 
which in warmer seasons of the year, comes on periodically every day ; 
yet in consequence of the identity of thé name, we are disposed to 
admit identity of character and to infer from one respecting the other. 



ON LIFE AND DEATH. $21 

parts in which they make their appearance. The trouble 
and excessive agitation of the animal life of such parts, 
compared with the calm of their organic life, are facts 
well worthy of remark. 

6th]y, Foetuses without heads, in the uterus, possess as 
active an organic life, as those which have no defect of con- 
formation whatever, and sometimes at the time of birth, 
are monstrous even in bulk; this circumstance I have 
frequently had occasion to observe at my amphitheatre ; 
the functions of nutrition then and circulation may take 
place with activity, though deprived of the influence of 
the brain : 

7thly, In animals, which have no cerebral mass, and in 
those (the polypes for instance) where not. even a nervous 
system is apparent, these organic processes are adroiraUly:^ 
well conducted,* the greater part of them indo4^i||Ni. 
common to the vegetable, and the animal. 

8thly, If the different proofs, which Bordeu has given 
of the influence of the brain over the functions be well 
eiçamined, it will seem that no one of them is decisive. 
The sudden interruption of the secreted fluid, in conse- 
quence of the division of the nerves of the part, would 
be the only proof which I should be inclined to admit as 
positive. Now I am not acquainted with any means of 
making such division with exactness. We have heard 
much of an experiment of this nature upon the parotids ; 
but the disposition of the nerves distributed to these 
glands is such, that I have not been even tempted to 

* What is the circulation of an animnl which exhibitfl no trace of 
yestels ? what inferences can be drawn for man from the mode of nutri- 
tion of a polypus ? what relation can be established between the com- 
plex function which presides in the mnmrnalia over the support of the 
orsrans, and the kind of imbibition bj means of which the zoophyte ii 
developed and preserved ? 

41 



322 PHYSIOLOCrCAL RESEARCHES 

repeat the experiment. The testicle is better adapted for 
the attempt, and accordingly without touching the vessels, 
I divided the spermatic nerves, but an inflammation and a 
deposit of matter took place in the gland, and with respect 
to the secretion of the semen, I could not judge of the 
effect of the division of the nerves. But here this very 
inflammation coming on without the influence of the 
brain, appears to me to infer a possibility of the seminal 
secretion under the same circumstances. In this experi- 
ment, the spermatic artery cannot be separated from the 
plexus which it receives from the great sympathetic, so 
intricate is the network of these nerves about it.; their 
division however is of little consequence, as they come 
from the ganglions. It is easy to break off all communi- 
cation with the brain, by destroying the lumbar fillets of 
nehres. 

I might add a number of other considerations to the 
above, but here 1 have to remark that the distinction of 
the sensibility and contractility into their two kinds is 
particularly worth attention. In fact, the idea of seosi- 
bility in our usual way of seeing things, suggests the idea 
of the nerves, the nerves again make us think upon the 
brain, we associate the three ideas, but excepting for 
the animal life they should not be associated. In the 
orgai\ic life, at least their union is not immediate. 

I do not mean to say that the cerebral nerves have no 
influence whatever over the organic sensibility, but I 
maintain that such influence is not direct and not of the 
nature of that which is observed in the animal sensibility. 

Many authors have already discovered a number of 
difficulties resulting from the opinion which makes the 
nerves the exclusive seat of sensibility, they have even 
sought for other means of explaining the phenomena of 
great living bodies. But of its agents we know as little 



ON LIFE AND DEATH. 328 

as we do of its nature, and have no means of elucidating 
questions of this sort. Let us be contented with analyz- 
ing, collecting and comparing facts with seizing their 
general results ; the aggregate of these researches will 
compose the true theory of the vital powers ; the rest is 
only conjecture : but besides the considerations which I 
have ofifered, there is another which manifestly goes to 
prove that the organic functions ^re not under the imme- 
diate influence of the brain, and this is, that the viscera, 
which perform such functions do not receive their nerves 
from the brain but from the ganglions. 

This anatomical fact is observable in the liver, the 
kidney, the spleen, pancreas, intestines, &c. even in the 
organs of the animal life there are nerves which serve 
for the external, and nerves which serve for the internal 
functions. In such the former come directly from the 
brain, the latter from the ganglions. Thus the ciliary 
nerves, which come ofif from the opthalmic ganglion, are 
those which preside over the secretions and nutrition of 
the eyes, the optic nerve which is derived from the brain 
is the nerve of vision.* In the same way the olfactory 
nerves of the pituitary membrane are the agents by which 
we have the perception of odours, the threads which come 
off from the ganglions of Mekel, relate only to the organic 
phenomena of the membranes. 

Now the nerves of the ganglions cannot transmit the 
action of the brain ; for we have seen that the nervous 
system derived from these bodies should be consrdered as 
entirely independent of the nervous system of the brain ; 
and that the great sympathetic does not derive its origin 

*The externa] ciliary nerves only come from a ganglion. The 
internal ciliary ones which have precisely the same distribution and 
€erve also very probably the same use?, come from a cerebral nerve, 
from the nasal branch of the ophthalmic. 



824 PHTSIOLOOICAL RESEARCHES 

from the brain, from the spinal marrow, or from the 
nerves of the animal life ; but from the ganglions exclu- 
sively ; this nerve indeed does not exist, it is only the 
aggregate of so many small nervous systems as there are 
ganglions, which are the particular centres of the organic 
life, just in the same way as the brain is the great and 
only centre of the animal life. 

To establish it as a fact that the great sympathetic such 
as it is understood does not in reality exist, I might add a 
number of proofs to those, which I have already mention- 
ed. The nervous communications, which are taken for 
it, are nothing more than accessories to the system of the 
ganglions; for 1st, These nervous communications, as 
Cuvier has observed, are not met with in the necks of 
birds ; between the upper cervical and first Ihoracic 
ganglion there is no vestige of a sympathetic. In birds 
then, the upper cervical ganglion is that which in man 
the opthalmic ganglion, the ganglion of Mekel and others 
are. This disposition, which is natural in birds, agrees 
with what I have sometimes observed in the human sub- 
ject between the first lumbar and the last thoracic ganglions, 
as well as between the lumbar and sacral ganglions them- 
selves. 2dly, In many instances there are no ganglions 
in the spot where the pretended sympathetic nerve com- 
municates with the spinal marrow. This may be seen in 
the human neck, and in the abdomen of fish, but such 
disposition should be thus regarded. The inferior cervi- 
cal ganglion furnishes a great branch which ascends to 
the superior cervical ganglion, and establishes between 
the two a direct communication ; but in ascending it dis- 
tributes many branches to each of the cervical nerves^ 
which form a secondary communication. 

It we reflect on these considerations^ together with 
those which have been already offered, we shall be more 



■c 



I « 



ON LIFE AND DEATH. S25 

and more convinced — 1st, That the çreat sympathetic is 
only an assemblable of small nervous systems, having each 
of them a ganglion for its centre, and all of them inde- 
pendent of each other, though generally communicating 
with the spinal marrow and between themselves. 2dly, 
That the nerves belonging to these small systems, cannot 
be considered as a part of the great nervous system of 
the animal life. 3dly, That the organs, which are pro- 
vided exclusively with the nerves, are not under the 
immediate influence of the brain. 

Notwithstanding which, we must not suppose that all 
the organs which serve for the internal functions, receive 
their nerves exclusively from the ganglions : many of 
these organs are furnished from the brain, and yet from 
experiment, it is found that they are not under the imme- 
diate influence of the brain. 

As yet we have only observation and reasoning for the 
basis of the important principle which we are labouring 
to establish, namely, that the organic functions are not 
directly put a stop to in consequence of the death of the 
brain ; but experiments upon living animals are not a less 
evident demonstration of this principle. 

1st, I have always observed, that in producing palsy 
or convulsion, 1 have never been able to impair in any 
very sensible or sudden manner, either the exhalation, 
the absorption, or the nutrition of the convulsed or palsied 
part.. " 

2dly, It has been for a long time known, that no spasm 
of the muscular fibres of the stomach, bladder, or intes- 
tines, can bé produced by irritating the nerves of the 
ganglions which go to these organs. 

Sdly, The division of the nerves of the ganglions, 
will not immediately paralyze the hollow organs. Their 
vermicular motions continue for a long time after the 
experiment 



.f 



336 PHYSIOLOGICAL Rl^EARCUES 

4thly9 With respect to the stomachy intestines, bladder 
and uterus, I have repeated the galvanic experiments 
which, with respect to the heart, have already been men- 
tioned at length; but never could obtain contractions.'*' 

5thly, The same experiments being made upon the 
organic muscles, and the great sympathetic nerve of a 
dog, there was no contraction. 

6thly, The issue of the latter operation may be easily 
conceived, according to our manner of regarding things. 
In fact, the ganglions, which are situated between the 
gastric organs and the nervous trunk of the chest, might 
possibly have interrupted the series of the galvanic phe- 
nomena. With â view, then, to remove all doubt of this 
kind, I exposed the nerves, which go from the ganglions 
immediately to the stomach, bladder and rectum, and in 
this way galvanised the organs but no contraction appear- 
ed to me to be the result of the experiment ; at least no 
contraction, which I could suppose to be the effect of 
galvanism, for here I cannot too much recommend a 
proper distinction to be made between that which should 
be the effect of this fluid, and that which results from the 
mechanical contact of the metals. 

7thly, These experiments are not easily made upon the 
intestines, on account of the tenuity of their nerves; but 
as these nerves compose a very perceptible plexus about 
the mesenteric artery, the intestine may be galvanized by 
surrounding the artery with one of the metals, while the 
other is placed under the intestinal tube* This experi- 
ment I have made, but could not obtain any sensible 
result. 

* The galvanic stimulas asaallj prodaces verj evident effects upon 
the contraction of the intestinal tube ; these motions are less evident 
in the stomach than in any other part of the canal; but the same 
difference is always observed whatever be the stimulât employed. 



ON LIFE AND DEATH. 327 

8thly, The preceding essays were made upon warm 
and red-blooded animals. Similar attempts were repeated 
on cold and red-blooded animals, but with no effect. 

Othly, The nerves which immediately supply the gas- 
tric organs of the frog, are so delicate as to make it an 
extremely difficult matter to get them into proper contact 
with the zinc : a small contraction of the stomach was, 
however, obtained by Jadelot on operating directly on 
these nerves ; but this contraction was similar, no doubt, 
to those which I have so frequently observed in other 
experiments, and not to be compared to the astonishing 
effects which are observable in the voluntary muscles. I 
shall conclude, therefore, that with respect to the galvanic 
phenomena, there exists a wide difference between the 
muscles of the animal life and those of the organic life. 

1 have now collected proof enough, I trust, for resolv- 
ing, with certainty, the question proposed in the above 
chapter, and for establishing it as a fundamental princi- 
ple — 1st, That the brain does not directly influence the 
organs and the functions of the internal life ; and 2dly, 
That, therefore, the interruption of these functions, in 
case of any great lesion of the brain, is not an immediate 
effect of such lesion. 

Nevertheless, I am far from considering the cerebral 
action as foreign entirely to the organic life. I only 
maintain that its influence upon it is indirect, and as yet 
but little known. I have been somewhat prolix upon 
this subject; for certainly nothing in medicine is more 
vague than the sense which is commonly attached to the 
words nervous actionj cerebral actiorif &c. There is 
never a proper distinction made between that which 
belongs to one life, and that which is the attribute of the 
other. Cullen, in particular, may be reproached with 
having exaggerated the influence of the brain. 



328 PHYSIOLOGICAL RESEARCHES 

II. Is the interruption of the functions of the organic 
life J the indirect effect of the cessation of the cerebral 
action ? 

The organic life continues to subsist for i certain time, 
after the apparent death of the individual. There must 
be some intermediate agents then, the cessation of the 
action of which, occasions the death of the inward organs. 
Such agents are chiefly the mechanical organs of respira- 
tion. Tiie series of the phenomena are the following : 

1st, The cerebral actions are interrupted. — 2dly, The 
mechanical functions of the lungs are put an end to. — 
3dlyy There is an annihilation of their chemical func- 
tions. — éthly. The black blood circulates in all the parts. — 
5thly, The movement of the heart and the action of all 
the parts is weakened.— Gthly, Suspended. 

All the inward organs then, die nearly as they do in 
asphyxia; that is to say — 1st, Because they are penetrated 
by the black blood. — 2dly, Because the circulation ceases 
to communicate that motion which is essential to their 
life. 

Nevertheless, there are many difierences between death 
from asphyxia, and death from lesion of the brain. 1st, 
The animal life in the latter sort of death, is generally 
interrupted at the very instant of the shock or blow. In 
the former it is terminated only in proportion as the black 
blood penetrates the substance of the brain. — 2dly, In 
the greater number of the asphyxias, the circulation does 
not immediately cease, the blood is only gradually black- 
ened, and continues for some time to be moved onwards 
by the agitation of such parts as are still under the 
influence of the brain. On the contrary, in lesion of the 
brain, the interruption of respiration is sudden ; the blood 



ON LIFE AND DEATH. 329 

also loses its red colour at once : on the other hand, the 
animal life being suddenly arrested, the organs of volition 
become immovable on the spot, and are capable no longer 
of favouring the motion of the blood. This remark is 
particularly applicable to the breast, the parietes of which 
facilitate very much the pulmonary circulation, and even 
the movements of the heart by their rise and fall, for 
in such alternation of motion consists the true influence 
which the circulation receives from the respiratory pro- 
cess. 

But after all, these two sorts of death may be more or 
less similar to each other according to the way in which 
they happen. The difierences which I have pointed out 
are by no means general. Thus, when asphyxia is sud- 
den, as when for instance the air of the lungs is pumped 
out with a syringe, there are neither livid spots, or fulness 
of the lungs to be met with. The circulation ceases 
quickly, and the phenomena of death are such as are 
observable when the brain is suddenly destroyed. 

On the contrary, if the death of the brain be slow, and 
the process of respiration for a certain time continued, 
the capillary system of the lungs will be gorged with 
blood, and the general capillary system be filled also. The 
circulation in such case will be slow to cease, and the 
phenomena of death like those of many of the asphyxias. 
Thus the promptitude or slowness of death, proceeding 
from lesion of the brain, will occasion all the difierences. 

It has been often a question in what way criminals 
die, who are hanged. In some, the vertebral column is 
luxated, and in others, want of respiration is the cause 
of death.* But whenever there is luxation, there is at 

* Death does not always take place in the same waj. It has been 
remarked, for example, that those who were hung at Ljons died quicker 
than those who were hung at Paris. In seeking for the cause of this 

42 



330 PHYSIOLOGICAL RESEARCHES 

the same time asphyxia, and in such case asphyxia is pro- 
duced, both because the pressure of the cord intercepts 
the psjtsage of the air, and because the intercostals and 
diaphragm are paralyzed. 

From what I have now said, 'a comparison may be 
made between the three kinds of death upon which I 
have expatiated. This comparison, according to my 
ideas, is of importance : I shall give some features of it. 
Generally speaking, there is a greater similarity in the 
two modes by which the death of the brain, or that of 
the lungs produces the death of the organs, than between 
either of these modes, and that, where the death of the 
heart is followed by the same effect. 

But 1st, There is always black blood in the red-blooded 
system, when death begins either by the brain or the lungs. 
When the functions of the heart are suddenly suspended, 
the arterial system contains a portion of red blood only. 

2dly, In the two first cases, the circulation continues 
for awhile ; in the third, it is immediately suppressed. 

ddly. When the death of the organs is a consequence 
of the death of the heart, they die, because they cease to 
receive that excitement to which they are accustomed 
from the motion of the blood. When their death is pro- 
duced by that of the brain or lungs, they die not only 
because they lose the excitement above-mentioned, but 
because they are penetrated by a fluid which is incapable 
of keeping up their actions, &c. The reader will easily 

finish the parallel which I have thus begun. 

• 

di/Terence, it was ascertained that in those who were executed at Lyons 
fhf're was almost always a luxation of the first or the second vertebra, 
which was owing to a rotatory motion, which the executioner gave to 
the criniiital in throwing him from the scaffold. The death was quick, 
because it was produced bj compression or laceration of the spina] mar- 
row ; it was slower in the other case in which it was only the result of 
asphyxia. 



ON LIFE AND DEATH. 331 

In red and cold-blooded animals, the death of the 
organs succeeds much more slowly to that of the brain, 
than in red and warm-blooded animals. We cannot assign 
the reason of this fact, because we do not know the differ- 
ence of the arterial blood from the venous blood of these 
animals, nor the effect which is produced on their organs 
by the contact of either sort of blood with them. 

When reptiles remain for a length of time under water, 
does the arterial blood become black from want of res- 
piration ? is the influx of such blood into their organs, 
pernicious or not ?* or is there a sufficient quantity of 
air contained in the large vesicles of the lungs of these 
animals to oxydate their blood for a length of time, af 
but little blood is capable of passing into the pulmonary 

* It appears by the beaotifal experiments of M. Edwards that frogs 
can live but a very short time in water deprived of air by boiling. 
Immersed in a small body of water containing air they soon die, no 
doubt after thpy have exhausted the air held in solution in the water. 
They can on the contrary live an indefinite tibie in this state of ii 
sion, if care be taken to renew the water sufficiently oftmi. The 
thinç happens, and still more certainly, if they are MUBened in run- 
ning water. 

It is not by pasf^ine^ the water throagh the longs, as the fish doM 
through the branchia:, that the frog obtains the air held in solntion by 
the water in which he is immersed, the fkin is m this case the sole 
respiratory organ. M. Rd wards is satisfied that this mode of respiration 
is not sufficient to support life, except between certain limits of tempera- 
ture ; a frog immersed in a volume of water which is not changed, 
continues to live fo much the longer as the temperature of this flnid 
approaches nearer 32**. At this degree frogs are not torpid, as migbt 
be supposed, only their motions are flower. 

As long as the animal immersed in the water remains perfectly aliye, 
which may be known by the vivacity of his motions, it is certain that 
the respiratory phenomena continue to be performed by him ; we seo 
in fact on the membranes in the interstices of the toes, the vessels 
filled with vermilion blood. When the black colour begins to appear, 
the animal soon becomes immoveable and insensible. 



332 PHYSIOLOGICAL RESEARCHES 

artery, which is only a branch of the aorta* The latter 
opinion appears to be confirmed by the experiment of 
injecting the lungs of a dog with a ki^ quantity of 
air, in which ease the blood of the creature is reddened 
for a greater length of time. But all these questions, 
notwithstanding the essays of Goodwyn, require much 
elucidation. 



CHAPTER XIII. 

OF THE IlfFLUENCE OF THE DEATH OF THE BRAIN OVER 
THAT OF THE BODY IN GENERAL* 

y 

From the consideration of what has been said in the 
preceding chapter, nothing can be more easy than to form 
an accurate idea of the manner in which the phenomena 
of general death, commencing by the brain, are concate- 
nated. The series is as follows : 

Ist, The cerebral action is annihilated. 2dly, There 
is a sudden cessation of sensation and voluntary motion. 
Sdly, A simultaneous paralysis of the intercostals and 
diaphragm. 4thly, An interruption of the mechanical 
phenomena of respiration and the voice. 5thly, An 
annihilation of the chemical phenomena of the lungs. 
6thly, A passage of black blood into the arteries. 7lhly, 
A slowness of circulation owing to the influx of such 
blood into the arteries, and the absolute immobility of all 
the parts, of the intercostals and diaphragm in particular. 
8th ly. The heart dies and the general circulation ceases. 
Sthlyi The organic life vanishes. lOthly, The animal 
heat, which is the product of all the functions^ disappears, 
llthly, The white organs die. 



ON LIFE AND DEATH. 333 

Though in this kind of death, as well as in the two 
preceding kinds, the functions are suddenly annihilated ; 
the parts retain, for a certain time, a number of the 
properties of life. The organic sensibility and contrac- 
tility, continue for some time, to be manifest in the 
muscles of the two lives ; and in those of the animal life, 
the susceptibility of being affected by the galvanic fluid 
is very great in the muscles of the animal life. 

This permanence of the organic properties, is nearly 
the same in every case ; the only cause which affects it, 
is the slowness with which the phenomena of death have 
succeeded each other. In every case where their duration 
has been the same, whatever may have been the cause of 
death, experiments instituted upon these properties, are 
attended with similar results ; for it is evident that con- 
cussion of the brain, luxation of the vertebrae, the section 
of the spinal marrow, apoplexy, compression of the brain, 
or inflammation, are all of them causes which are attended 
with a like effect. 

The same, however, is not the case with respect to the 
asphyxiae produced by the different gases. We have 
shown the reason of this in the more or less deleterious 
nature of the gases which produce asphyxiae. 

The state of the lungs also, is very various in the bodies 
of persons who have died from lesions of the brain. 
This organ is sometimes gorged and sometimes almost 
empty : it shews, however, whether the death of the 
individual has been sudden or gradual. The same indica- 
tion may be had from the state of the exterior surfaces. 

The death, which is the consequence of disease, com- 
mences much more rarely in the brain, than in the lungs. 
Nevertheless, in certain paroxysms of accute fever, the 
blood is violently carried to the head, and is the occasion 



326 PHYSIOLOGICAL HliISEARCHES 

4thly, With respect to the stomach, intestines, bladder 
and uterus, I have repeated the galvanic experiments 
which, with respect to the heart, have already been men- 
tioned at length; but never could obtain contractions.* 

5thly, The same experiments being made upon the 
organic muscles, and the great sympathetic nerve of a 
dog, there was no contraction. 

6thly, The issue of the latter operation may be easily 
conceived, according to our manner of regarding things. 
In fact, the ganglions, which are situated between the 
gastric organs and the nervous trunk of the chest, might 
possibly have interrupted the series of the galvanic phe- 
nomena. With a view, then, to remove all doubt of this 
kind, I exposed the nerves, which go from the ganglions 
immediately to the stomach, bladder and rectum, and in 
this way galvanised the organs but no contraction appear- 
ed to me to be the result of the experiment ; at least no 
contraction, which I could suppose to be the effect of 
galvanism, for here I cannot too much recommend a 
proper distinction to be made between that which should 
be the effect of this fluid, and that which results from the 
mechanical contact of the metals. 

7thly, These experiments are not easily made upon the 
intestines, on account of the tenuity of their nerves; but 
as these nerves compose a very perceptible plexus about 
the mesenteric artery, the intestine may be galvanized by 
surrounding the artery with one of the metals, while the 
other is placed under the intestinal tube. This experi- 
ment I have made, but could not obtain any sensible 
result. 

* The galyanic stimulas ataallj prodaces very evident effects upon 
the contractioD of the intestinal tube ; these motions are less evident 
in the stomach than in any other part of the canal; but the same 
différence is always observed whatever be the stimulus employed. 






ON LIFE AND DEATH. 327 

8thly, The preceding essays were made upon warm 
and red-blooded animals. Similar attempts were repeated 
on cold and red-blooded animals, but with no effect. 

Othly, The nerves which immediately supply the gas- 
tric organs of the frog, are so delicate as to make it an 
extremely difficult matter to get them into proper contact 
with the zinc : a small contraction of the stomach was, 
however, obtained by Jadelot on operating directly on 
these nerves ; but this contraction was similar, no doubt, 
to those which I have so frequently observed in other 
experiments, and not to be compared to the astonishing 
effects which are observable in the voluntary muscles. I 
shall conclude, therefore, that with respect to the galvanic 
phenomena, there exists a wide difference between the 
muscles of the animal life and those of the organic life. 

1 have now collected proof enough, I trust, for resolv- 
ing, with certainty, the question proposed in the above 
chapter, and for establishing it as a fundamental princi- 
ple — 1st, That the brain does not directly influence the 
organs and the functions of the internal life ; and 2dly, 
That, therefore, the interruption of these functions, in 
case of any great lesion of the brain, is not an immediate 
effect of such lesion. 

Nevertheless, I am far from considering the cerebral 
action as foreign entirely to the organic life. I only 
maintain that its influence upon it is indirect, and as yet 
but little known. I have been somewhat prolix upon 
this subject; for certainly nothing in medicine is more 
vague than the sense which is commonly attached to the 
words nervous action^ cerebral action^ &c. There is 
never a proper distinction made between that which 
belongs to one life, and that which is the attribute of the 
other. Cullen, in particular, may be reproached with 
having exaggerated the influence of the brain. 



tf 



ON LIFE AND BEATH. 339 

also loses its red colour at once : on the other hand, the 
animal life being suddenly arrested, the organs of volition 
become immovable on the spot, and are capable no longer 
of favouring the motion of the blood. This remark is 
particularly applicable to the breast, the parietes of which 
facilitate very much the pulmonary circulation, and even 
the movements of the heart by their rise and fall, for 
in such alternation of motion consists the true influence 
which the circulation receives from the respiratory pro- 
cess. 

But after all, these two sorts of death may be more or 
less similar to each other according to the way in which 
they happen. The difierences which I have pointed out 
are by no means general. Thus, when asphyxia is sud- 
den, as when for instance the air of the lungs is pumped 
out with a syringe, there are neither livid spots, or fulness 
of the lungs to be met with. The circulation ceases 
quickly, and the phenomena of death are such as are 
observable when the brain is suddenly destroyed. 

On the contrary, if the death of the brain be slow, and 
the process of respiration for a certain time continued, 
the capillary system of the lungs will be gorged with 
blood, and the general capillary system be filled also. The 
circulation in such case will be slow to cease, and the 
phenomena of death like those of many of the asphyxiae. 
Thus the promptitude or slowness of death, proceeding 
from lesion of the brain, will occasion all the differences. 

It has been often a question in what way criminals 
die, who are hanged. In some, the vertebral column is 
luxated, and in others, want of respiration is the cause 
of death.* But whenever there is luxation, there is at 

* Death does not always take place in the same way. It has been 
remarked, for example, that those who were hung at Lyons died quicker 
than those who were hung at Paris. In seeking for the cause of this 

42 



330 PHYSIOLOGICAL RESEARCHES 

the same time asphyxia, and in such case asphyxia is pro- 
duced, both because the pressure of the cord intercepts 
the passage of the air, and because the intercostals and 
diaphragm are paralyzed. 

From what I have now said, a comparison may be 
made between the three kinds of death upon which I 
have expatiated. This comparison, according to my 
ideas, is of importance : I shall give some features of it. 
Generally speaking, there is a greater similarity in the 
two modes by which the death of the brain, or that of 
the lungs produces the death of the organs, than between 
either of these modes, and that, where the death of the 
heart is followed by the same effect. 

But Ist, There is always black blood in the red-blooded 
system, when death begins either by the brain or the lungs. 
When the functions of the heart are suddenly suspended, 
the arterial system contains a portion of red blood only. 

2dly, In the two first cases, the circulation continues 
for awhile ; in the third, it is immediately suppressed. 

3dly, When the death of the organs is a consequence 
of the death of the heart, they die, because they cease to 
receive that excitement to which they are accustomed 
from the motion of the blood. When their death is pro- 
duced by that of the brain or lungs, they die not only 
because they Jose the excitement above-mentioned, but 
because they are penetrated by a fluid which is incapable 
of keeping up their actions, &c. The reader will easily 

finish the parallel which I have thus begun. 

• 

di/Terence, it was ascertained that Id those who were executed at Lyons 
there was almost always a luxation of the first or the second vertebra, 
which was owing to a rotatory motion, which the executioner gave to 
the criminal in throwing him from the scaffold. The death was quick, 
because it was produced by compression or laceration of the spinal mar- 
row ; it was slower in the other case in which it was only the result of 
asphyxia. 



ON LIFE AND DEATH. 331 

In red and cold-blooded animals, the death of the 
organs succeeds much more slowly to that of the brain, 
than in red and warm-blooded animals. We cannot assign 
the reason of this fact, because we do not know the differ- 
ence of the arterial blood from the venous blood of these 
animals, nor the effect which is produced on their organs 
by the contact of either sort of blood with them. 

When reptiles remain for a length of time under water, 
does the arterial blood become black from want of res- 
piration ? is the influx of such blood into their organs, 
pernicious or not ?* or is there a sufficient quantity of 
air contained in the large vesicles of the lungs of these 
animals to oxydate their blood for a length of time, af 
but little blood is capable of passing into the pulmonary 

* It appears by the beautifal experiments of M. Edwards that frogs 
can live but a very short time in water deprived of air by boiling. 
Immersed in a small body of water containing air they soon die, no 
doubt after thpy have exhausted the air ht^ld in solution in the water. 
They can on the contrary live an indefinite time in this state of imoter- 
sion, if care be taken to renew the water sufficiently often. The aaoie 
thing happens, and still more certainly, if they are inaerBed in run- 
ning water. 

It is not by passinç: the water throagh the longs, as the fish docs 
through the branchia), that the frog obtains the air held in solution by 
the water in which he is immersed, the fkin is m this case the sole 
respiratory oi^an. M. Rdwards is satisfied that this mode of respiration 
is not sufficient to support life, except between certain limits of tempera- 
ture ; a frog immersed in a volume of water which is not changed, 
continues to live fo much the longer as the temperature of this flaid 
approaches nearer 32**. At this degree frogs are not torpid, as migbt 
be supposed, only their motions are slower. 

As long as the animal immersed in the water remains perfectly aliye, 
which may be known by the vivacity of his motions, it is certain that 
the respiratory phenomena continue to be performed by him ; we see 
in fact on the membranes in the interstices of the toes, the vessels 
filled with vermilion blood. When the black colour begins to appear, 
the animal soon becomes immoveable and insensible. 



i 



t ^^ 



^