i^^

a.i'

t

G.& 1^

FROM THE LIBRARY

OF

Dr. CHARLES VOSE BEMIS,

MEDFORD, MASS.

THE GIFT OF

Dr. NORMAN FITCH CHANDLER,

TO THE

BOSTON MEDICAL LIBRARY,
1907.

Digitized by tine Internet Arciiive

in 2011 with funding from

Open Knowledge Commons and Harvard Medical School

http://www.archive.org/details/courseofmedicals03burd

A

COURSE

OF

MEDICAL STUDIES :

CONTAINING

A COMPARATIVE VIEW

OF

THE ANATOMICAL STRUCTURE
OF MAN AND OF ANIMALS ;
A HISTORY OF DISEASES;

AND

AN ACCOUNT OF THEKNOWLEJDGE HITHERTO ACaUIRED "WITH

REGARD TO THE REGULAR ACTION OF THE

DIFFERENT ORGANS.

" A WORK CHIEFLY DESIGNED FOR THE USE OF
MEDICAL STUDENTS.

BY J. BURDIN, M. D.

TRANSLATED FROM THE FRENCH.

IN THREE VOLUMES. .
VOL. III.

LONDON:

PRINTED FOR CUTHELL AND MARTIN, MIDDLE-ROW,

HOLBORN3

BY P.. \V1LKS, CHANCERY-LAKE.

1803.

' SEP 11 -^

-\ \

CONTENTS

OP

THE THIRD VOLUME.
PART SECOND CONTINUED.

C/.ONVULSIVE AFFECTIONS . . . . Page ^

Palpitations of tlie heart . . . . . . 2

Convulsions of the larynx ., . . . • 3

Thoracic cramps ....... 4

Asthma . < . . . . . . . . 9

Spasmodic affections of the oesophagus ... 10

Rumination . ... . . . . .12

Hiccup 13

Cardialgia sputatoria . . , . . ,15

Gasti'odynia. Colic of the stomach . . . .1(5

Intestinal colic . . . . . . . .17

Metallic colic. Colica pictonum. Rachialgia metallica 28
Convulsions ........ 34

Trismus. Locked jaw .,...• 35

Opisthotonos . . ib.

Emprosthotones . . . . , . ,3(5

Tetanus 40

Hydrophobia . ib.

Epilepsy . . . . . . . . 52

Vesanic affections . . . • . . ,53
Hypochondriasis . . . . . . ,56

Hysterics ........ 59

Nymphomania ....... 62

Satyriasis . . . . . . . . .63

Melancholy .06

Mania . . , • ib.

A 3 Different

^^^

VI CONTENTS OF

Different forms of mania

Page 70

RECAPITULATION OF THE HISTORY OF DIS-
EASES . . . . .80

General considerations on the development of diseases . 82
Development of diiferent phlegmasiae, and their termina-
tion . . . . , .85

Phlegmasia from vi^ounds , . . .86

Phlegmasia from a prick . ■ . . .90

Phlegmasia qf the serous membranes - . . • 9^

Phlegmasia of the white fibrous tissue . , .98

Rheumatism . ' . . . • ' 99

Catarrhs . . , . . .104

Cutaneous diseases . . . , .108

The itch ... . . . 109

Glandular tumours . . . ..112

Scrophulous constitution . . . .113

Syphilis . . . , . .114

Syphilitic blennorrhagia . . . .11/'

Scirrhous tumours , . . . .120

Phlegmasiae of the bones . . , .124

Mortification of tlie bones . , . ,126

Eruptive fevers . . . , .133
Simple intermittent fevers .... 139

Pernicious remittent fevers . . . .142

Simple and pernicious remittent fevers . .148

Comatose affections . . . . . 152

Astlienic affections . . . . .156

Of convulsive and vesanic affections . . ' . 158

General considerations on nervous affections . . 159

PART THIRD,

VITAL FUNCTIONS

Action or the brain and nerves

. 177

. ib.

Reciprocal

THE THIRD VOLUME. Vlt '

Reciprocal action of tlie brain and vessels . Page 177

General disposition of the cerebral system . .1/8

Different sensibility of the parts according as they derive
their origin from the encephaion^ its rachidian
prolongation^ or the ganglions of the trisplanch-
nic . . . . . .183

Life and health result from tlie regular distribution and

proper employment of the nervous action . 184

185

ib.

189

ib.

ib.

IQI

193

104

ib.

ips

Life maintained by the action of stimulants

Of^the different sensations

Action of the bones . . ,

General disposition of the system of the bones .

Connection and structure of tlie bones .

Their development

Coloration of the bones by madder

Luxations .....

Action of the muscles . . .

General disposition of the muscular system

Conti'action of the muscles . , . •

Muscular force

Dexterity and agility of motion acquired by exercise and

the force of habit . . , .

Station and progression

Of sensations ....

Action of foreig^n substances on our or^^ans
Action of the atmosphere

How the organization retains its habitual temperature
Action of cold ....

Action of heat . ...

Action of light . .

Action of electricity . . , .

Action of humidity . . . ,

Reciprocal action of foreign substances on our organs,

and of our organs on these substances .
Foreign substances tend to combine chemically witt our

organs ....

^99
200
202

ib.

ib.
205
20(jf
207
209
210
211

ib.

ib.

All

VUl

CONTENTS OF

All the organs make an effort to digest and absorb all sub-
stances suited to them and to reject others Page 212
Aftei" birth the first irapressions and the first wants give
rise to a general disorder which produce tlie first
painful sensations . , . .210

Inipressions produce livelier sensations according as the

nerves affected proceed directly to the brain . 217
Fqi"eign substances produce a change of state in tlie or-
ganization by their contact with the nei'ves of
the partS;, and not by tlieir absorption and pass-
ing into the blood .... 219

Eecapltulation of these observations . . . 221

Okgans of the senses . ... 223

These organs receive all their nerves from the encephalon

by a very short passage . , . iK

Sense of touching . . . . . , ib.

Tissue of tlie skin . , , s . ~ ib.

Sense of touching belongs to the whole skin . . 224

Sense of tasting . . * . . . 225

Sapid bodies . . . . . .226

Sense of smelling ... . . . ib.

Of odorous bodies . , , . . ib.

Sense of seeing ..... 229

Progress of light in the eye . . • . 230

Nature of that. sensation . . , . 234

Strabismus .. . . . . . 239

Blyopia . . . . . . 240

Presbyopia . . . ... 241

Sense of hearing , . . , . 244

Nature of sound ..... 245

Its progress . . . . . . 246

Effect of music . , . - . ' 249

Uses of the different pails of the ear , . . 252

Deafness . . ■ . . . .254

Simultaneous action of the organs of the senses, and of

the muscular system from the period of birth . 255

The

THE TBIKD VOLUME. IX

The organs of the senses and those of loco-mofion consti-
tute relative life ... -Page 257
Isfatnre and development of sensations . . 258
Of renewed sensations ; in what manner tliey are renewed 2@l
Of the combination of direct with renewed sensations 27 1
Development of the intellectual faculties , , -.- 273
Action of the system of digestion . . 282
Of hunger and thirst ..... 283

Mastication . . . . . . 2S5

Deglutition , , . ' „ . ', 2S6

Digestion of the aliments in the stomach . . 287

Digestion in the duodenum .... 288

Action of the bile and of the pancreatic juice . . 289

Absorption of the chyle . . . . 2p2

Phenomena which result from derangement of the gastric

. system . . . ' . • . 205

Action of the aliments on the nervous system . . 297

Action of medicines ..... 301

Digestive action of the gastric organs on the aliments,
and simultaneous action of the aliments on the
gastric organs . , ' . . 303

Action of the organs of circulation" and ke-

spiration . ' . . . . 307

General progress of the blood , , . ib.

Contractile force of the heart and arteries . . 308

Of tlie pulse . , . . . . 309

Termination of the arteries and origin of rhe veins . 310
Phsenomenon of nutrition is effected between these two

orders of vessels . . , .311

Nature of this phaenomenon . . - . ib.

How the elevation of the tempefature of the blood results

from the phaenomenon of nutrition . , Zl^:

Keturn of the blood by the veins "and the lymphatics , Z15
Progress of tlie blood in tiie veiiii . . . ib

Of the lympatic vessels .' . . ,310

Change which" the lymph experiences in the lymphatic

glands . , . * .317

Theory

X CONTENTS OF

Theoiy of the humourists . . . Page 319

Exper'iments which prove that it is erroneous - . 320

The blood is freed from its excess of heat by evaporation

of the cutaneous organ . . . .321

The blood freed from its excess of aqueous parts, and of

different saline substances, by the urinary passages 324
Phenomenon of urinary secretion . . . ib.

Of the colour which the urine assumes after the use of

certain substances . . • • 320

frspection of the urine in diseases . . • 323

The venous blood repairs its losses by the product of di-
gestion . . . . • 331

Venous blood frees itself from tire materials of the bile in

its passage through tlie liver . . . 332

Peculiar phsenomen a of tlie secretion of the bile . 333

Erroneous idea of the bile passing into the blood . 334

Analogy of the function of the liver witli that of the

lungs . ..... 335

Passage of the blood into the left side of the heart . 336

Its passage thence into tlie pulmonary organ . . 337

Changes which the blood experiences in its passage

through tlie lungs . . . .333

Changes which the atmospheric air experiences in respi-
ration ,..,., 340
Different theories ojn respiration . . ■ . 341

Of the different kinds of asphyxia . . . 345

Of the movement of inspiration and,expiration — forma-

tion of sound . . . . 34g

Of the vocal organ in birds' . . . , ib.

Of tlie vocal organ in man .. . . . 350

Action of the organs of repkoduction . 354

Of reproduction in general in tlie different classes of or-
ganized beings . . . . ib.

Eeproduction in the mammalia . . . 360

Kutritiv^e apparatus of the germs in tlie different classes

of or_a"iz-d beings . . , , , 362

Of crossing biccda i . . . . 3^0

Of

THE THIRD VOLUME. ' XI

Of reproduction in man

•

; Page 372

Of puberty

•

. ib.

Of fecundation

.

. 373

Development of the foetus, and of its

placenta

.- 375

Of parturition .

.

. 376

Secretion of milk

.

. 377

Derangements of that function

.

. 379

Various errors on this subject .

.

. ib.

Of the different races of men .

,

. • . 381

Effect of crossing the breed

.

. 383

Recapitulation of the knowledge acquired in regard to

the organic functions .

c

. 389

Conclusion ,

•

. 433

A COURSE

MEDICAL STUDIES.

HISTORY OF DISEASES.

CONVULSIVE AFFECTIONS.

157. The (yftems of organs, which are fafceptible,
as already (hown, of different degrees of weaknefs,
and which in this ftate exhibit various affedlions,
may be alfo exalted or deranged in their a6lion, fo
as to perform only with trouble and diforder the
fundlious affigned to them. In this cafe they
prefent phasnomena of difeafe exceedingly nume-
rous and varied.

158. The heart exhibits fometimes in its mo*
tions a very remarkable acceleration. During its
rapid and irregular pulfations, it often ftrikes the
ribs with fuch force as to produce a very fenfible
fioife : this is frequently found to-be the cafe after
violent running/

voL/iir. B The

% HISTORY OP DISEASES.

The circumflances capable o{ producing palpi-
tations of the heart are of two kinds :

One kind depend on an organic alteration of
the heart, or of the large veffels ; a dilatation of
thefe parts ; and on all caufes capable of exciting
any obftacle to circulation.

The other kind arife. merely from a derange-
ment ip. the nervous a&ion of the heart. The
latter |r§, frequently remarked in individuals who
have fuch a ftate of irritability, that, if it does not
alone produce palpitations, it increafes, in a lingu-
lar manner, the influence of the other caufes cal-
culated to excite them.

In the cafe of palpitations which arife from an
organic alteration of the heart, there is no hope of
a cure. The paroxyfms of thofe only which de-
pend on a derangement in the nervous action of
that organ, can be diminifhed or retarded, by re-
moving the caufes capable of accelerating the cir-
culation.

When they arife only from great irritability of
the nervous fyflem, they require the application
of general means fuited to all kinds of convul-
fions. FaJpta lions of the heart,

159. In fome individuals very much difpofed
or even fubje6!; to convulfive movements, and par-
ticularly in women, there fometimes fuddenly
comes on, for a quarter or half an hour, an im-

poilibility

CONVULSIVE AFFECTIONS. - 3

poflibility of articulating, or at leaft with theufual
tone and precifion ; the perfon makes fruitlefs at-
tempts, as if to expel the mucous matter which
obftrufts the larynx. Sometimes an involuntary
and incoercible flow of words takes place; an
emiilion of the ftrangeft founds, paffing abruptly
from grave to acute, and vice verfa, with aftonifh-
ing difcordance, and fometimes refembling the
cries of different animals*. The voice however
js at length, fometimes, redored without any ex-
cretion. Convuljions of the larynx.

Impediment or abolition of the voice depends,
in other cafes, on palfy of the larynx.

1 60. The thorax is the feat of a peculiar affec-
tion f, which announces itfelf by a fenfation of
conflri(?tion, rather incommodious than painful j
pain is felt along the ilernum for a greater or lefs
extent ; and in general there is experienced, at the
laTHii^ trme, in both arms, but rarely in one, a
cramp towards the infertion of the great pedloral
mufcle, or in the fore-,arm towards that of the
round pronator. The paroxyfms take place in
confequence of caufes exceedingly various, and
they even vary much themfelves, in regard to the

* See Portal, Mimoires de la Soclete Medicale.
t London Medical Journal, vol. v. — Macbride's Introduftion,
£« the Prai^ice pf Medicine.

B 2 intervals

4 HISTORY OF DISEASES.

intervals and to the duration. Sometimes they
laft an hour or -two ; in fome cafes their return has
been prevented by the ufe of wine or opium.

The ftriking influence of moral afFedlions on
the returns of this difeafe-^ its long duration,
without any other derangement of the health ; the
ftate of the ftomach ; the relief almoft always
afforded by the ufe of corroborants^ by riding on
horfeback or in a carriage, by varying the occupa-
tions and diverting the mind, indicate that this
affedlion, which is merely nervous, does not arife
from an organic alteration, and that it has its par-
ticular feat in the mufcles of the thorax. It exhi-
bits fome analogy with chronic rheumatifm. Tho-
tacic crani'ps-

i6i. Among women, but more frequently among
men, efpecially when very corpulent, is obferved
an affe<51ion which is often hereditary, and which
feerns to have its feat in the different parts- of --'Ihe
organ of refpiration.

This affeciion comes on by paroxylms, and ex-
hibits a pretty regular progrefs. The patient,
during the whole day which precedes the paroxyfm,
experiences great agitation, a flight headache, hea-
vinefs in the limbs, and a fmall degree of oppref^
iion at the,breaft. Some hours after dinner he
becomes fubjecl to great oppreflion, accompanied
with a fenfation of plenitude about the ftomach,

flatulencies^

CONVULSIVE AFFECTIONS, 5

flatulencies, difienfion of the epigaftrium, and
erudation of an.infipid matter. On the approach
of night a httle hoarfenefs is felt, with a conftric-
tion of the bronchi^ and of the tracheal artery;
during night, a heat which will not admit of the
bed-clothes remaining on the bread, and a fort of
convulfive cough. There is no expedloration, or
it conlilts of ferous matter in very fmall quantity,
TJie fenfation at the ftomach is lefTened by cold
beverages, and particularly by water.

One or two hours after midnight the paroxyfms
feem to commence by an increafe of indifpolition j
refpiration, exceedingly difficult and flow, is per-
formed wiih a fort of hoarfe, hilling noife, and
renders it neceflary to affume a vertical polition.
The diaphragm feems to move only with great dif-
ficulty, and to be drav/n back into the breaft by
the mediaftinum. The patient experiences a fen-
fation of conftridlion in the lungs, and imagines
that thefe organs are contrac^lcd and pufhed to-
wards the uppei* part of the thorax. He makes
violent efforts to enlarge his breaft, and is incapa-
ble of coughing, fpitting, or fpeaking wiih free-
dom. He experiences exceffive beat ; the pulfe
is quick, clofe and unequal ; the feet and hands
are cold; the face is fometimes blackifhj the eyes
fparkle, and difcharge involuntary tears, which
fomctimes tinge the cheeks yellow. The lips. are
difpofed in a form as if about to fack.

B 3 Sorae-

Q HISTORY OF DISEASES,

Sometimes the patient gets up, places himfcif
at th"e window, whatever be the feafon, and refpires^
while ftanding, with more facility. In fome cafeSj
the diftenlion of the abdomen feems to decreafe;
the difficulty of breathing is leflened ; and there
comes on an ample evacuation of fascal matters
and of flatulencies, which affords rehef.

In general the fymptoms continue for feveral
hours, and even fometimes to a pretty late period
in the morning. After a little fleep, however,
refpiration is lefs laborious; the acft of fpeaking
and the cough become lefs difHcult. Sometimes
a mucous expedloration takes place, and the re-
mifTion is then always more fenfible. The urine
is lefs abundant, more highly coloured, and gene-
rally fedimentous. During the whole day the
patient experiences a confi:ri(9:ion at the breaft,
and a difficulty of breathing when he afTumes a
horizontal pofition, or makes any movement. After
dinner flatulencies take place ; he becomes drowfy
in the evening, and the difficulty of refpiration
gradually increafes. Sometimes, however, refpi-
ration is pretty free, and fleep tranquil for a part
of the night; but from midnight till two in the
morning the patient is fuddenly awaked by an at-
tack of a fecond paroxyfm, fimilar to the firfl:.

The paroxyfms are thus continually renewed for
four or five nights ; expe(51 oration daily increafes
in the morning, and the remiffions are propor-
tionally

CONVULSIVE AFFECTIONS. 7

tionally lefs fenfible. Sometimes the paroxyfm is
preceded only by a little drowfinefs towards the
evening. In this cafe it continues not more than
two or three days, and when the patient is up he
expedlorates a ferous matter. But in the cafe of
the greateil intenfity the difeafe continues for four
or five days, with the ufual exacerbations every
night. The expedloration does not begin till the
third or fourth day ; at firft it is in fmall quantity,
becomes progreffively lefs vifcid, white or yellow-
ifh, and is fometimes marked with bloody firiaB.

A firft attack of this difeafe gives reafon to
prefage, in an infalHble manner, periodical returns
during the remainder of life. Sometimes thefe re-
turns feem to be produced by great heats, and
violent emotions ; by certain odours, fmoke, fnuff^
duft, &c. and by every thing capable of abating or
accelerating the movements of the breaft.

Some individuals experience more frequent ac-
ceffions in fummer, and particularly during the
oppreffive heat of the dog-days ; others are oftener
and more feverely ajERidled in the winter. But at
this period the difeafe, for the moft part, is ac-
companied with a catarrhal defluxion of the bron-
chia?. In all cafes, however, the patients are
fpeedily afFed^ed by fudden changes of tempera*
lure *.

Some

* Floyer, who kept a very exa6l journal of his difeafe for
fcven years, relatcSj that thsfe paroxyfms were more violent, and

a 4 of

3 HISTORY OF DISEASES.

Some find themfelves better in the air of great
cities; others in that of the country; but al-
moft all prefer the dry free air of low di{lri6ls to
that of the mountains. Damp, foggy air in ge-
neral is prejudicial to them, as well as' damp habi-
tations in marihy places. They are fatigued by
heat, but can very well endure cold, and even a
pretty intenfe degree of it ; which fufficiently
indicates that the atmofphere beft fuited to them
is always that moft abundant in oxygen^ little
charged VN^th moifture, and which is not fubjefl
fo too great or too frequent changes. The infpi-
ration of air with an increafed proportion of oxy-
gen may be ufeful to them.

Light animal food and vyater are much better
fuited to fuch perfons than flatulent aliment and
fpiritous liquors. Riding on horfeback or in a
carriage, and fea voyages, afford relief.

Emetics fonpetimes have appeared ufeful in this
affedtionj efpecially when it is catarrhal ; when
given before 'the acccfiion they fometimes pre-
vent it.

This affe6lion, in general, produces no derange-
longer duration, in fummer than in winter, but particularly in
the month of Auguft, and that the expectoration then became
thicker. The return of the paroxyfms took place for the moft
part in the courfe of the three days preceding or following the
full or the new moon, and fometimes alfo towards the quadra-
tures.-— Van Helmont alfo obferved a relation between the par-
oxyfms and the phafes of the moon,

ment

CONVULSIVE AFFECTIONS. g

ment in the reft of the organization ; md there
are inftances of people who have been fubje6l to it
fifty years, without any other inconvenience.

The acceffions, however, rarely recur often, for
a confiderable length of time, without producing a
general emaciation. In fome young perfons it has
been feen to terminate very fopn by a pulmonary
phthiiis; fometiraes alfo it produces hydro-thorax.

It is probable that the perturbing fyftem of treat-
ment is that beft calculated to efFe6l a complete
cure of this difeafe, efpecially in the commence-
ment, and before the paroxyfms; by exciting either
in the ftomach or in the tides of the thorax a repeat-
ed and continued irritation, capable of removing
that of the organs of refpiration, which produces
the fpafmodic or convullive fymptoms of ajlhma,

162. In perfons fubjeti to convulfions, and to
all thofe caufes by which they are produced,
there comes on foaietimes by paroxyfms an affec-
tion of the oefophagus. Deglutition is difficult
or impoilible, and this fymptom is accompanied
with a contraction or ftiffnefs of the tongue, of the
larynx, and of the whole neck; a lufFocating con-
ftraint, and a fenfation as if fome body had ftuck in
the fauces : fometimes there is alfo a tranJitory or
permanent aphonia.

In other cafes deglutition at firft appears to be
free, but the fubltances fwallowed flop at a parti-
cular

10 HISTOEY OP DISEASES.

cular point of the cefophagus, and for the moft part
near the ftomach. Warm liquors pafs with more
freedom than cold ; the patient at the fame time
experiences a pain along the fpine, naufea, frequent
efforts to vomit, flatulent eru6iations, and throws
up limpid mucus with the matters which have been
fwallowed.

Sometimes the two feries of phaenomena here
enumerated are obferved, either limultaneoufly or
with conflant or irregular alternations. In this
cafe, the patient experiences a fenfation as-if fome
body obflrufSted the osfophagus ; and of flatu-
lencies afcending and defcending, without eru6la-
tion taking place. Thefe varieties feem to depend
on the different parts affedled.

In general, thefe affections come on by par-
oxyfms, and vary very much in regard to the in-
terval, ftrengtb and duration. At the fame time
there is often a coldnefs in the extremities of the
limbs, and particularly the feet ; fometimes trem-
bling, fuppreffion of the itools, abdominal fpafms,
palpitation of the heart, &c. Th.hfpafmodic affec-
iio72 of ihe cefophagus is very often accompanied by
the other convulfive difeafes.

There are other obftacles to deglutition, which
arife from,

ift, Atonia or palfy of the cefophagus. In this
cafe, folids pafs with more eafe than liquids {Fahr,
de Hilden). The latter run along the larynx, and

are

CONVULSIVE AFFECTIONS. II

are fent back, through the noftrils and the mouth
with danger of fufFocation. This frequently takes
place in the advanced ftage of continued perni-
cious fevers.

2,d. From an acute phlegmafia : anginsc, &c.

3d. The prefence of fome voluminous body flop-
ped in the oefophagus; a Vv'ound, ulcer, tumour, or
excrefcence in its fides ; a confiderable fwelling
of the glands of the neck ; a fcirrhous Hate of the
cefophagian orifice of the ftomach ; a luxation of
the OS hyoides.

163. By a convulfive contra(5lion of the fto-
mach, afi^fted by a fudden (hock of the diaphragm
and of the abdominal mufcles, the matters con-
tained or affluent in the ftomach, the duodenum,
and fome other inteftines, are fomctimes thrown
up in the adl of vomiting.

This difeafe arifes from a nervous affedlion, a
phlegmafia of the ftomach, dift^erent irritants in-
troduced into that organ, or which develop them-
felves in it.

This aifedlion is only lymptomatic in fome
acute difeafes, and in fome phlegmafia; of the ab-
dominal vifcera, &c. It is often produced by a
coritra6lion, a fcirrhous tumour, or a cancer of the
pylorus and of the duodenum, a ftranguiation or
ftridlure^ nodofity, intus-fufception or adhefion of

the

1'2 HISTORY OP DISEASES.

the inteftines, and by every obftacle to the free
courfe of the matters in the inteftinal canal, &c.

But the vomitings often appear to be entirely
analogous to convulfive affe6lions, and in that
cafe may fometiraes be exoted by the influ-
ence of the imagination. This influence refults
from the afpe6Vof the vomiting, and from all thofe
pbje^ls and circumftances which may recall the
remembrance of it. In forne perfons it may be
produced feveral times by an accidental caufcj
and then continue by the force of habit, notwith-
Handing the abfence of the caufe which at firll
produced it. It then always exhibits periodical or
son'tant returns,

564. Peyer relates feveral examples of perfons who
liad the faculty of bringing back into the mouth
the aliments they had fwallovved, in order to maiti-
cate them at lei fa re {De Meijcologld). In fome
individuals this habit, initead of being an incon-
venience, appears to be agreeable, and to get rid of
it, nothing would be ncccfTary but a determined
refolution. In others, it is entirely involuntary,
and feems to arife from a real convuliion of the
ftomach, irritated by the prefence of aliments in-
troduced too fiiddenly, a'nd in too large quarftity.
It is, in particular, after an exccfs of gormandizing
that this fpecies o{ rumination \s renewed.

165. There

CONTULSIVS AFFECTIO^rS. 13

165. There is an inftantaneous and reiterated
afFe<9:ion5 which confifts in a fudden fliock given
to the bread and abdomen by a fpafmodic con-
tra{5iion of the diaphragm. It is accompanied with
an acute found, ftronger or weaker, which appears
to arife from an exploiion of the air contained in
the ftomach and the oefophagus.

In certain cafes, hiccup is merely a fymptom of
fome derangement of the gaftric lyftem, fuch as
colic of the (lomach, the inteftines, the kidneys,
Sec. a ftrangulated hernia : it is alfo a troublefome
fymptom of fome acute difeafes in an advanced
flate.

Hiccup, in general, refults from a momentary
irritation of the (tomach, when that organ has fud-
denly received too large a quantity of aliments or
of alcoholic liquors. It appears to be produced
alfo fometimes by an inflantaneous irritation of
the osfophagus and of the diaphragm.

Hiccup fometimes is really fpafmodic; and,
without feeming to refult from any caafe, may
continue a long time by a fort of habit*.

Though hiccup, for the moft part, is frequently
renewed, it is fcarcely an indifpolition. While it
takes place, a flov/ and long infpiration, fneezing
purpofely excited, a fudden furprife, unexpe61ed
news, a fright, and every powerful diftradlion, are

, * Tulplus, Riviere, Fcrnelius, &c. fpeak of a hiccup of this
kind which frequently returned for feveral months.

Sufficient

14 HISTORY OF DISEASES*

fufficlent to remove it ; which might induce a be-
lief that in thefe cafes it is merely a fpafmodic af--
fe6tion.

In the laft place, when hiccup is the fymptom of
another difeafe, the latter alone deferves attention,

1 66. There is an afFe^lion diftinguifhed by a
dull or acute pain in the epigalb'ium, with a
diftenfion or contra(5lion of the ftomach, flatulen-
cies, eru61ations, vomiting, he. The general in-
difpofition and ftate of the pulfe depend on the
intenfity of the difeafe. This difeafe feems to pro-
ceed from a fpafmodic or weak ftate of the fto-
mach, which in many circumflances varies. The
principal variations we fhall here defcribe. Some-
times this difeafe arifes from an afFe6lion of the
pylorus ; from the action of emetics, violent pur-
gatives, poifons, &c.

In perfons below the middle age, and in thofe ■
even who have not attained to puberty, but parti-
cularly in women, it fometimes comes on fponta-
neoufly. It manifefts itfelf, for the moft part, be-
fore meals, by pain with a fenfation of con{tri<5lion
in the epigaftric region ; the ftomach feerns to be
ftrongly pulled towards the back, and the body
leans forwards j v,'hich in fome meafure diminiflies
the uneafinefs. After a certain time the erudta-
tion becomes eafy, or rather there flows off a large
quantity of aqueous liquid, fometimes acid, and at

other a

CONVULSIVE AFFECTIONS. 15

others perfet5lly infipid. After fome erudations
in clofe fu€C€ffion, the pain decreares and entirely
vanidies.

This tranfient inconvenience, which however
is apt frequently to return, is in general more
troublefome than painful. It terminates fpoota-
neoufly ; is met with in our climates, and was ob-
ferved by Linnaeus in Sweden. Cardialgia fpula-
toria.

Feeble perfons, convalefcents, and chiefly wo-
men, and thofe in particular whofe organs of di-
geftion are exhauited by the long ufe of tepid
aqueous beverage and aliments, or by the abufe of
different Itimulants, are very much fubje^l to
this difeafe, which is readily renewed by violent
mental atTedions, ftrong fenfations, and by certain
kinds of food. In thefe cafes they experience,
fome hours after meals, towards the epigaftric re-
gion, diftention or tumefa6lion, dull or acute pains^
with fufFocation, and great fenlibility to the touch
in the region of the ftomach : eru6lation of acid or
fweetifli matter then takes place, and fon:ietimes
vomiting ; which affords relief. In fome cafes this
flate is accompanied by a coldnefs of the limbs.

This difeafe fometiraes depends alfo on convul-
five affe6tions, and accompanies them. It is then
chara<51erized by an acute pain in the ffomach,
with anxiety, (hortnefs of refpiration, and efforts to
vomit : Ihivering, a fudden proftration of ftrength,

and

id HISTORY OF DISEASES,

and a fenfalion of approaching fyn^ope, at the
fame time take place. The pain, which at firft
feems to arife from the pylorus, extends to the reft
of the ftomach, and towards the fpine. Sometimes
a tumour, nearly of the lize of an egg, manifefts
itfelf a little to the right of the fternal appendix i
eructation produces a flight relief. . During the
greateft violence of the difeafe, the limbs are cold,
and the pulfe is fmall and confined, 'At length heat
is reftored, with an univerfal fweat ; the pulfe be-
comes large and foft, and the pain gradually ceafes.
The numerous relations which the ftomach has
with the other parts caufe this organ frequently
to participate in their derangements; fo that this
difeafe, which we have often leen to be differently
eflential, is very often only fymptomatic. It may
therefore be determined by an irritation arifing
from a calculus in the urinary or biliary canals : it
often precedes febrile and gouty attacks ; it forms
the prevailing fymptom of a variety of intermittent
pernicious fever; and it accompanies the interver-
fton of a great many difeafes, fuch as dyfenteryg
gout, &c. CoTic of the Jiomach.^ Gajirodynia,

167. The inteftinal canal is the principal feat of
a difeafe which appears to be entirely fpafmodic:
it is characterized by acute pains in the abdomen,
which ceafe and are renewed at very fhort in-
tervals.

In

CONVULSIVE AFFECTIONS. jy

In hiiejl'mal colic ^ the pains are more acute when
they take place towards the umbilical region, and
ieem to proceed from the fmall inteftines. The
patients for the moft part experience a fenfation
of diftenlion and twitching, which proceeds from
fome point of the inteftinal canal, and extends by
little and little. The inteftines are in a ftate of
conftipation, which gradually increafes, fo as to
prevent all efcape of the flatulencies. The pulle
is always fmall, hard, clofe, and convulfive.

The difeafe, in its progrefs, exhibits intervals,
very much varied, of calmnefs or limple remiffion ;
and at its higheft degree there often come on fhi-
verings, tremor, great agitation, extreme anxiety,
naufea, vomiting, at firft of mucous, then of bili-
ous, and laftly of ftercoraceous matter. Sometimes
hiccup, delirium, convulfive movements, cold
fweats, fyncope, &c, are obferved, and, in fome
cales, vefical tenefmus.

In fome individuals a flatulent tumefa(5lion of
the belly takes place, with extreme fenfibility to
the touch ; a fenfation of tenlion and pain in the
ftomach, efforts to vomit, and flatulent eru6lation
which affords relief.

Others experience opprefiion of the abdomen^
a retradlion of the navel, violent contra6iion of the
abdominal mufcles, which become hard, and ex-
hibit their form beneath the integuments ; a con-

voL, III. c fliridtion

18 HISTORY OF DISEASES.

ltrif?^ion of the anus, which does not admit the
iatrodudion of a dyi^er. In this cafe the belly-
is not painful wheii touched, and fometimes even
the pain is diminifhed by preirure.

The feverity of the difeafe depends on the in-
tenfity of the fymptoms, and particularly on the
force of the conftipation.

The colic generally ceafes on the appearance of
fome phasnomena of particular affedions: fuch as
nafal and h hemorrhoidal haemorrhagy, cutaneous
eruption, fit of the gout^ diarrhoea, &c. pains in the
joints.

Sometimes fever and violent heat come on j the
pulfe is hard, frequent, and clofej the patient ex-
periences unquenchable thirffc; and violent, con-
ftant, and fixed pains indicate a local phlegmafia.
(See that article.) In fome cafes, then, a fudden
ceflation of the pain, univerfal calmnels, prollra-
tion of the ftrength, weaknefs of the pulfe, cold
fvveals, fcfitidity of the mouth, and frequent ly^n-
cope, announce a gangrene.

This difeafe is mod frequent among children.
Old perfons, women, and weak individuals of great
fenfibility. The habit of a flight conftipation, the
ufe of debilitating food, fuch as aqueous, fweet,
faccharine, flatulent, &c. vegetables, chiefly pro-
duce a difpofition towards this afFe6lion. It may
be occafioned by expofure of the feet to cold or

dampnefs ;

Convulsive affecItions. 1^

dampnefs > by a violent fit of paffion^ particularly
in youth ; by excefs at table, and by many other
caufes.

It is the efFe(5l alfo of an Organic derangement
in theinteftines ; fach as the obftrudion of a point
in the alimentary canal by a ball of hardened ex-
crementi {Hoffmann^ Henry de Hears,') or by a large
calculus, a flrangulated hernia, a callofity, a fcir-
rhus, (jCerkring, Baillou,) a cartilaginous ring, the;
torfion of a part of the inteftines, their intus-fuf-
ception, a ball of worms entwifted together {Henry
de Heers).

This difeafe is a conftant lymptom of hypochon-
driafis. It frequently fucceeds alfo fome eflential
afFedlions, accompanies others, and appears to be
the refult of every caufe which produces a fudden
derangement in the ufual progrefs of a phenome-
non of health or of difeafe.

It fucceeds an interruption o( the gout, men-
ftrual and haemorrhoidal fuppreffions, &c. It ac-
companies the exigence of a calculus in fome parts
of the urinary or hepatic tjflem, the labour of

dentition, &c. * /

Colics

* The coilc which fucceeds or accompanies any derangement may
arife from the caufe of that derangement, or from fome foreign
caufe, and in either cafe the irritation produced ori the inteftines
may be too ftrong to put an end to the concomitant difeafe.
Colic may be produced alfo by every caufe which difturbs the
ufual progrefs of a phaenomenon of health or of difeafe. But, in

c 2 ' all

20 HISTORY OF DISEASES.

Colics differ very much from each other, in cori-
iequence of the different caufes by which they are
produced ; of the feat of the pain, and the feverity
ofthe fymptoms. On thefe bafes, however, no
very flriking diilindtions can be eftabhfhed ; but
there is one which exhibits a prominent character,
and a conftant progrefs^ which renders it of im-
portance to give a detailed hiftory of it.

1 68. This colic, which has been known at Paris
for more than two centuries, has been obferved in
Germany, and defcribed by Dehaen and by Stoll ;
it has been obferved alfo at Madrid, at different
periods, and recently by Luruiiaga. In all thefe
places, and at all times, the defcription of it has
been fundamentally the fame. It has always been
afcribed to a certain aciion of preparations of lead,
fwallowed, or received into the bronchias. Citois
has defcribed a colic which took place in Poitou in
i6i6, and Huxham another, which took place in

• all thefe circumftances, the difappearance of the firft afFeftion
ought not to be afcribed to the tranfportation of a material and
morbific afFedion to the inteftines, but to an interruption of the
nervous affe6lions, occafioned the one by the other : and it is as
ridiculous to fay that a colic is produced by the tranfportation to
the inteftines of a gout which has difappeared, as It would be to
aifert, that the colic which follows or accompanies fuppreflion of
the menllrual fliix^ or the prefence of a calculus, is produced by
the tranfportation to the inteftines of the uterine flux, or of the
urinary and bilious calculus.

Devonfliire

CONVULSIVE AB'FECTIONS. 21

Devonfhire in 1724, both very analogous to the
one in queftion. The former of thefe writers af-
cribes the one in Poitou to the four wines of that
country j and the latter, the one in Devonfhire, to
the cider, which that year had been exceedingly
abundant. Sir George Baker, however, haslince
aflerted, that the colic of Devonfhire ought rather
to be afcribed to the lead employed in the mills and
cifterns being diflTolved by the acid of the apples,
and becoming mixed with the cider. Journal des
Savans, Jan. 1768.

This difeafe, however, attacks in particular work-
men employed in lead manufadtories, who are ex-
pofed to the fumes arifing from that metal; and thofe
who drink liquors which hold it in folution. But
it appears certain that, independently of the influ-
ence of the lead, a peculiar difpofition or aptitude,
which it is impoffible to determine, is alfo required.
Stoll fays, he remarked in almoft all the patients
attacked by this difeafe a certain appearance in the
face and eyes, which prefented fomething maniac,
an air of fliupor, an habitual thoughtfulnefs, he.

This afFeftion announces itfelflliddenly, or in a
flow manner, by extraordinary dejedion, languorj
watchfulnefs, loiathing, a derangement in the ftools ;
wandering pains take place in the epigaftrium,
v/ith a fen fat ion of heavinefs in the ftomach imme-
diately after meals; the ftools are rare, hard, and
m fraall bits» There are obferved afterwards an

C3 3ir

0,2 HISTORY OF DISEASES,

air of intoxication, vertigo, ftupor, and dimnefs of
iight : all thefe fyinptoms are temporary, and fre-
quently recur, &c.

Soon after the conflipation increafes ; in which
cafe the perfon experiences excruciating pains in
the abdomen, a fenfation of tearing and twifling
in the inteftines, which is renewed at fhort inter-
vals. The pains, which in general are fixed to-
wards the cefophagian orifice, or the whole abdo*
minal region, follow the diredlion of the ureters to^
wards the bladder; alfe£t the fcrotum, the thojax,
and even the limbs, like an acute rheumatifm. The
pains for the moflpart are not increafedby touch^
ing ; and prefTure of the abdomen very often gives
relief. At other times, however, the epigaflrium can
fcarcely endure the lightefl; covering. Sometimes
the belly is foft ; but in general it is hard, dif-
tended and uneven : the navel is turned round,
and fhrinks towards the fpine, with hardnefs and
tetanic contraction of the abdominal mufcles. A
fpafmodic confi;ri6tion of the inteftines, which,
under the integuments, exhibit the appearance of
hard rolls, is obferved ; often a velical tenefmus ;
fometimes a fhortening or almofl fudden difap-
pearance of the penis; the fcrotum becomes al-
ternately contrafted and relaxed ; the teflicles ex-
perience a retraction, or fort of painful rotjition.

During a great part of the difeafe the patient
9 ^"^7

CONVULSIVE AFFECTIONS. 23

very often experiences vomiting, fometimes with
hiccup. He has no ftools, notwithftanding the
ulc of injeftions or purgative draughts; or thereare
voided only a few very hard globules, with exceed-
ingly painful tenefmus, and a little bloody mucous
matter. When frequent and copious ftiools take
place, they always afford relief.

During almoll the whole courfe of the difeafe
the patient exhibits an aftonifhed, thoughtful, or
even maniac air ; his mind is reftlefs, turbulent,
impatient and fickle.

■ At the commencement the pulfe is nearly in its
natural ftate ; during the progrefs of the difeafe, it
is fometimes frequent and unequal, and the dimi-
nution of the pain is always preceded by a flight
febrile paroxyfm, which terminates in a copious
fweat. Towards the termination, a gentle motion,
followed by the dejection of hard globular excre-
ment, or even of vifcid matter, mixed with mucous
flakes, is perceived in the abdomen. The pains
then flowly decreafe ; the appetite is reftored only
gradually ; the flomach becomes confiderably
fwelled after meals ; and the nights continue to be
reftlefs.

Sometimes the difeafe produces a fenfation of
curvature accompanied with weaknefs, cramps,
or fhooting pains in the limbs, tremors, or even
mufcular impotence, pains in the breafl, and tranfi-
ent difficulty of refpiration.

c 4 In

24 HISTORY OF DISEASES.

In fome very fevere cafes the vomiting is alarm*
ing, and produces the rejedion of ftcrcoraceous
matters, ivith hiccup : fyncope, cold fweats, partial
or epileptic convulfions, take place ; and if the pa-
tient efcapes death, the pains are then continued
forfeveral vi^eeks, with intervals of remifiion.

In the courfe of the difeafe, paliy very often
takes place in fome of the limbs =^, particularly in
the arms, the handsj and in fome of the fingers,
but rarely in the pelvian limbs, and never un-
lefs the thoracic be affected alfo. The palfy only
fufpends the mufcular adtion^ without injuring fen-
fation, and in different cafes exhibits fhades ex-
ceedingly varied, from fimple tremor, heavinefs
and inaptitude for motion^ to complete paralyfis.
In general, there always remains a flight degree
of contradilityj at leaft in the flexors. In cer-
tain.cafes a weaknefs of the voice is obferved, with
hoarfenefs, aphonia, difficulty of refpiration, amau-
rolis, deafnefs, &c. and various tranfient but re-
peated fymptoms.

The palfy may take place at different periods of

the difeale t.

In

* According to Stoll, fifteen patients exhibit only one example
of palfy, and it is a little obftinatc only once in twenty-five
cafes.

t It was after this palfy that Dehaen obferved a deltoid muf-
cle which to the touch prefented nothing but a membranous
fubflance, and all the raufcles of the arm and fore-arm, with the

CONVULSIVE AFFECTIONS. 15

in a confiderable number of patients, and efpe-
cially thofe who have been already feverely afFed:-
ed at different times, there arife on the backs of the
hands tubercles as large as peafe, at firft painful^
which yield to the prelTure of the finger, and fpeed-
ily refume their former flate. Thefe tubercles,
which afterwards acquire hardnefs, and a chara6:er
of indolence, appear generally on the attack of the
difeafe, and fometimes even before the appearance
pf any other fymptom.

This difeafe varies in regard to its duration, from
a few days, for example, to feveral months ; fome-
times it continues years, and in this cafe it is more
troublefome by its obflinacy than its violence. In
general it is not very mortal.

The body, when opened, exhibits organic alter-
ations, which may throw feme light on the nature
of the difeafe. Conflriclions or flrangulations are
found in feveral partsof the inteflinal canal, of the
duodenum, the ilium, the coscum, and the re£lum.

fat, the ikin, the tendons, and nerves, were converted into a fort
of pulpy ligament. At the fame time, feveral perfons aflfcfted
by the fame palfy had the fle{h of the arm more or lefs flaccid.
'- In the body of a man who had died of the leaden colic, Hun-
t-er found the mufcles of the arm and hand, which before death
had been emaciated, as v/hite as cream j the fibres of them were
diltin6t, but drier than ufual, Zalzmann, in the Journal des
Savaiis for 1735, gives an account of a man forty years of
agC;, in whom a great many mufcular portions of the right th'gh'
aiid leg were found converted into fat.

Thefe

0,6i HISTORY OF DISEASES.

Thefe Urangulations are often feparated by very
ample dilatations. Sometimes thele contraftions
difappear immediately after death ; at other times
they continue two or three days. It evidently ap-
pears that, on the termination of the malady, they
are entirel}/ diffipated, fince a relapfe feldom occurs
without a new caufe. It is, however, to be pre-
fumed that they fubfifl, or are renewed, when the
patients continue to be frequently fubjed to flight
colics and hard globular llools. In fome cafes,
portions of the inteftines are found fhrunk, and al-
moft converted into ligament. In a word, phlo-
gofcs have been found in the mcfentery, in the in-r
teftines, in the ftomach, in feveral of the abdominal
and thoracic vifcera, &c, with extravafated blood,
echymofes, and vibices. (See Bordeu). There is
reafon, however, to believe that thele alterations
have no relation to the moll common cafesj but
only to thofe rare circumftances under which the
difeafe, when carried to an extreme degree of
violence, brings on phlegmafia, and perhaps even
a gangrenous and fphacelous ftate.

It is evident that this difeafe has its principal
feat in the inteftines, and the intenftty of the local
lymptoms gives rife to the other remote accidents.

The particles of lead (in all probability oxidated)
which produce this afFedion, feem to exercife an
immediate a6tion on the organs of digeftion in per-
fons who drink, licjuors holding this metal in folu-

tion.

CONVULSIVE AFFECTIONS. 2?*^.

tion. When workmen, however, are habitually
expofed to refijire air in which fome of it is {-jf-
pended, it is not probable that the difeafe arifes
from particles introduced into the ftomach by
deglutition : it is much more probable that the
firft a6iion of the lead is exercifed on the bron-
chial furfaces; and that it proceeds to the in-
teftines, on which this metal feems to have a
fpecific adion. Several fubftances exercife a fiOii-
lar a6lion, and in a fimilar manner, on the fame
organs, whatever be the parts which they aiFe61:.
The vifcera of the breaft are often afFedled in this
difeafe,iince there are obferved hoarfenefs, aphonia,
cough, a fpafmodic difficulty of breathing, &c.
'Two methods, which feem to be diametrically
oppofitCj and which have been attended withequal
faccefs, are employed in the treatment of this dif^
eafe. This peculiarity is worthy of notice, as it is
of importance to the hiftory of the organization.

169. Oneofthele methods, founded on the ge-
neral principles, of medical obfervation, fees in this
difeafc, as well as in others, a progrefs which it is
proper to refpe£t ; and employs only mild and
fimple means, calculated to promote a favourable
termination.

The other, entirely empiric, which is more
adive and decifive, conlifts in violent emetics, ex-
ppedingly fi:rong purgatives, repeated without di-

flindiion

<2g HISTORY OF DISEASES.

ftinftion every two days. This method is that
followed at prefent in the Hopiial de la CharitS,
only that a flight dofe of opium has been added.
It is fuppofed that this method mull be attended
withipeedier fuccefs, as violent emetics and purga-
tiveSj the principal adion of which, in regard to
the inteftinal conftriftion, can be exercifed only
on the llomach, produce in it an irritation fuffi-
ciently ftrong to remove the fpafm of the inteflines,
which oppofes the evacuations. .But it may be
readily feen what opinion ought to be formed of
this method, when it is known that it is employed
with th,e abfurd and ridiculous intention of opening
the heJly and forcing theharrier % and whether there
is not more reafon to be alarmed on account of
the accidents it may produce, than to be confident
in the advantages likely to refult from it. Stoll
having oblerved that momentary fuccefs only was
obtained, in flight cafes, by emetics and purgatives,
and that the difeafe was alraofl always exafperated
by them, had at length recourfe, in the moil de-
fperate cafes, to opium, contrary to the advice of -
Dehaen : he obtained a cefiation of the pains and
vomiting ; had fpontaneous flools, and then opium
became his purgative*. Metallic colic ^ Colic a pic-
tomim, Rachialgia metallica.

170. The

* In this difeafe opium, as we have feen in tetanus, may be ad-
ininifiercd in ftrong dofes without producing ileep. Stoll gava

CONVULSIVE AFFECTIONS. 20

170. The different organs of motion may expe-
rience a convulfive affection, which takes place by
iparoxyfms, and continues a (liort time. This af-
fection, for the moft Tp?LX\ifymptomatiCi is fometimes
ejfential.

In the firft place, it accompanies fbme conlider-
able derangements. It comes on, therefore, after
an irritation produced in any pai"t in confequencc
of wounds, fra61ures, luxations, tumours, &c. ; by
tenlion, compreflion, the pun(9:uring or laceration
of fome of the nervous reticulations; after an or-
ganic Iseiion of the brain, the collc6lion of any fluid
in its cavity ; an affe61ion of the uterus ; the exift-
ence of calculus. This difeafe may be the effe6l
alfo of a firfi: difficult menflruation, of parturition,
of the prefence of poifon in the ftomach or elfe-
where, and of worms in the inteftines. In chil-
dren it frequently accompanies the attack of erup-
tive fevers and dentition ; in adults it precedes,
and fometimes follows, the fiidden fuppreffion of a
natural or morbific* fecretion ; that of all organic
functions which are habitual'^, or which have be-

•fix French grains with fix grains of camphor in twenty-four hours.
He even carried the dofe to thirteen grains- Dr. Gendron gave fo
much as ninety-fix grains with fix ounces of fyrup of diacodium
in three days, without producing fleep. Rcc. period, de la Soc,
dc Medecine, vol, ii.

• Supprelfion of the menftrual flux; of difeafes of the ikin of a
long Handing ; of old ulcers and emunftorles, &c.

f Tndigeftion, difappearance of the gout, &c.

. come

30 HISTORV OF DISEASES. -

come fo ; In a word, any fudden interruption \n
the natural progrefs of the vital operations^ and in
that of acquired habits. It is then probable, that
what is here called difeafe Is, in many cafes, only
an effort of vitality to recover from fome fudden
derangement, and to attain to the complete ufe of
its fun6lions.

When this difeafe is elTential, it afFe£ls chiefly
the feeble and delicate children of cities, defcended
from parents of a highly irritable conftitution, and
long expofed to the empire of violent paffions. It
is common alfo to adults, and particularly womew
endowed with an excefs of fenfibility, and ealily
agitated by the flighteft caufesi always extrava-
gant in their affeftions, and who proceed with afto-
nifhing rapidity from one very flrlking emotion to
■one diredlly oppofite. (Mutatur in horas. Horat.)

Perfons fubjedt to this difeafe are generally
loaded with a great deal of flabby and entirely lym-
phatic corpulency. Sometimes, however, they are
pale, meagre, dry, and, as we may fay, all ner-
vous; their fleep is generally reftlefs j they are
troubled with frightful dreams ; have a variable
appetite, rare flools, and much rarer fweats*

The paroxyfms feem often to be determined by
fome violent mental affeftion ; at other times they
come on fpontaneoufly, without any apparent
caufe : their duration, as well as the length of the
intervals, is exceedingly various.

Some

CONVULSIVE AFFECTIONS, 31

Some authors think they have fometimes ob-
ferved, in the return of the paroxyfms, a regular
periodicity, and even a coincidence with the phales
of the moon.

On the approach of the paroxyfms arc obfcrved:
fleep not profound, interrupted by groundlefs fears;
fudden movements in the fingers, the arms,and legs;
the eyes fixed or wandering ; the pupils dilated,
and fome mufcles of the face agitated by con-
vulfive motions : fbon after, coldnefs, a pricking
in the exterior parts, and particularly in the
feet, a fenlation of cold water running along
the back, yawning, palpitation of the heart,
anxiety in the prascordia, abdominal fpafms, uni-
verfal tremor, pulfe hard, unequal and confined.
All thefe Ij'mptoms exhibit great anomalies, and
the attack is often fadden.

The paroxyfm announces itfelf by fudden agi-
tation in different parts of the body ; contorlion in
various directions ; extenfion, but oftener flexion
of the limbs, which proceed a great way beyond
the ufual limits ; fometimes by luxations or frac-
tures. The eyes are fometimes clofed, fometimes
open and projefting, fixed or violently agitated ;
fpafmodic movements of the jaw, cheeks, and
mouth take place ; the tongus is thrull out between
the teeth, and in that flate is often bitten. The
vocal organs exhibit convulfive affections alfo, and

in

31 HISTORY OF DISEASES,

jn this cnfc lofs of fpeech, and even of volcej i$
the confcquence ; refpiration is fometimes fl^^rt,
with lymptoms of fuffocation : at length palpita-
tion of the heart and violent cardialgia are obfervedj
fevere griping pains in the belly, and coftivenefs;
the urine ceafes to flow, or becomes highly limpid.

There is no part of the body which may not be
.afFe6led, either fingly, or in conjun6lion with a
greater or lefs number of others. In fome cafes
the fpafms are confined to one part only ; in others
they proceed fuddenly from one part to another,
without any regular or certain progrefs. Some in-
dividuals remain in the fame pofition in which they
were when attacked by the difcafe, or at leaft af-
fume that nearly which gives them mofi: fatisfac-
tion ; others fall down, and exhibit every appear-
ance ofepilepfy, — only that the intelleciuai faculty
remainSj and fenfation is not annihilated. In ge-
neral, there is no foam at the mouth ; the patient
is confcious of what takes place around him, and
remembers it, at leaft in a confufed manner.

In general, the mufcles poilefs a contra^ile
force, which refifts the greateft efforts ; but at the
end of the paroxyfm they fall into a ftate of per-
feS: relaxation ; the patient experiences extreme
languor, a fort of fainting, and fometimes pro-
found drowfinefs. In fom.e the tei-mination of the
paroxyfm is announced by flatulent eru6lations,

abundant

CONVULSIVE AFFECTIONS. 33

abundant vomiting of mucous matter ; bloody or
mucous evacuations from the nofe, uterus, haemor-
rhoidal veins, &c.

In many individuals of a conflitution exceed-
ingly weak and fenfible, this difeafe feems often to
arife from the fudden impreffion produced by the
fight of a fimilar ftate; by the dread of the fame
evil ; or by the remembrance of this afFeflion in a
perfon fubje6t to it, but chiefly from the irrefifti-
ble tendency to imitation.

A paroxyfm of convulfion, in general, exhibits
nothing in itfelf dangerous, efpecially when the
conftitution is found, and when it arifes from an
accidental caufe. But if the individual is weak, or
if the firfl: caufe continues, and is frequently re-
peated, the multiplicity of the paroxyfms renders
the malady in fome meafure habitual. Thefe
paroxyfms, frequently repeated in this manner,
progreffively exalt the fenfibility, and difpofe the
individual for receiving the influence of a multi-
tude of new caufes ; fo that the paroxyfms approach
each other more and more, merely for this reafon,
that the individual has already experienced a great
many. It is thus that repeated eftbrts to fham con-
vulfions at length give rife to real and fometimes
incurable movements of this kind.

This convulflve habit often brings on, and is ac-
companied with, hypochondriafis, melancholy, ma-

voL. Ill, D nia.

34 HISTORY oy disease's,

nia, &c,; and death at length takes place by a fit
of apoplectic epilepfy,

Convulfions which fucceed a violent haemor-
rhagy, any immoderate evacuation, or fevers, are
much to be apprehended. On the other hand, when
they precede eruptive fevers, and fome other dif-
eafes, they appear to be advantageous* Convulfions,

171. There is one difeafe which confilts eflen-
tially in a fpafmodic contradion of the mufcles.

It attacks individuals of both fexes, of all ages,
and in all climates, but particularly in warm coun-
tries, near the fea, expofed to damp winds ; in
marfhy difi;ri6l3, where the temperature is fubje6l
to great and fudden variations ; at feafons when
thefe variations are more fenfible, and in the time
of ftorms accompanied with cold rains.

It is veiy common, violent^ and mortal in Ame-
rica, where it frequently attacks the negroes, and
particularly the children, foon after birth.

An aCe(Slion very analogous is found in the
cramp, which is common and as it were endemial
in Java and Ceylon.

This difeafe, which is very prevalent at Surinam,
feems often to arife from a violent mental afFe6lion,
or concentrated anger. This fpecies, common at
Beziers, and in part of the fouth of France, is
diftinguiflied thereby the name oi Mai deVdme,

Obfervation

CONVULSIVE APPfeCTlONS. 35

Obfervation feems to indicate as the caufes of
this difeafe : ftrong mental afFe(5lions ; the fudden
impreffion of intenfe. and particularly damp cold
after a hot temperature ; the prefence of worms in
the inteftines: it comes on alfo in confequence
of wounds or chirurgical operations, and in this
cafe does not manifeft itfelf till the end of feme
days.

The development of this difeale is, for the moft
part, flow and gradual. There firll comes on a
fenfation of ftiffnefs towards the nape of the neck,
which by degrees increales, accompanied with con-
Uraint and pain in moving the neck. Deglutition
afterwards becomes difficult, and then impoffible :
in this cafe there is often a violent pain at the bot-
tom of the fternum, which extends thence to the
back, with a fudden contradlion of the cervical
mufcles, which (Irongly pull the head backwards.
At the fame time the jaws have an infuperable
tendency to approach each other. The difeafe
fometimes remains at this degree, and is known by
the name of a locked-jaiv. Trifmus,

In other cafes are obferved frequent returns of
fternal pain, cervical and maxillary fpafms ; and
during the further courfe of the difeafe a fpafmodiq
-rigidity of the doifal mufcles takes place, and thq
whole body is thrown backwards {Opfilfotoms)*
The limbs then become ftiff and inflexible; th§
(ides of the abdomen appear very hard, and as if
drawn back by the contraction of the mufgles of

D 2 that

30 HISTORY OP DISEASES.

that cavity. In the lall place, a violent contra6tion
takes place in the flexor mufcles of the head, the
neck, and the trunk {emprcjflhotonos), an exten-
lion and uniform rigidity of the trunk and limbs, (o
that, in railing the feet or head, the whole body
flands ere61 like a plank : the arms and lingers are
the laft parts which become llifF. Towards the end
of the difeafc, the tong-ue is fometimes thrufi: with
violence between the teeth ; all the mufcles feem
then to be afFcfted ; the forehead becomes corru-
gated ; the eyes turn round, and in general remain
fixed ; the note fhrinks, and the cheeks are drawn
backwards.

^ When the general tpalin has continued fomc
minutes at the higheft degree of force, with ex-
cruciating pains and piercing cries, there comes
on a certain ftatc of remifl^on and calmnefs, but
which does not lafi: a quarter of an hour ; and
the fpafms and pains foon recur with their for-
mer violence. In the courfe of the difeafe, ob-
flinate watchfulnefs takes place ; the individual
for the mofi part retains the free ufe of his in-
telle6l and fenfes : fometimes, however, his ideas
feem confufed, and his mind is even completely de-
ranged. Refpiration is difficult, the voice hoarfe,
third infatiable, with an impoflibility of fwallow-
ing. The urine, fometimes ilipprefl^d, iiiues with
difficulty, or in jets, when the bladder is com-
prefied: conflipation is habitual.

In the laft place, towards the end; a fort of prii-
. -. ritus.

CONVULSIVE AFFECTIONS. 37

rltus, or pricking, is experienced in the fpine ; a
fenfation analogous to that of a liquid flowing tO'
wards the facrum ; a gradual diminution of the
iymptoms, or a cold, abundant, and univerfal fweat,
convulfions, and death.

The difeafe^ fometimes partial, confines itfelf to
the mufcles of the jaw and neck, either anterior,
pofterior, or lateral. At other times it is univerfal,
and keeps the body in a ftate of perfect rigidity,
extended, or bent backwards, forwards, or towards
the fides. The pains are often confined to certain
parts, fuch as the head, the bottom of the mouth,
one fide of the breall:, the epigallrium, the loins,
and the limbs. In the lafl place, Salivation, fyn-
cope, tremor of the limbs, &c. may take place.

In fome cafes, the progrefs of the difeafe is ra-
pid, and produces death in thirty or thirty-lix
hours ; and, for the mofl part, before the fourth
day. It is when the difeafe comes on in confe-^
quence of wounds (traumatic) that its progrefs is
moll rapid. After the fourth day the danger de-
creafes; but there is always reafon to apprehend
new paroxyfms as fatal as the firft. The fymptoms
never difappear fuddenly : they decreafe gradu-
ally, and fometimes require a conliderable time be-
fore they ceafe entirely.

Sometimes the progrefs is flower: the convul-
iive movements, which are traniitory, come on by
repeated paroxyfms, and at intervals which vary

D 3 from

38 HISTORY OF DISEASES.

from one hour to feveral minutes; the jaws are
never forced exadtly together ; deglutition, though
difficult, is always poffible j the body is flightly
bent forwards; the patient cannot bear to re-
main in a recumbent pofture, and can enjoy no
reft but by placing himfelf in a tranfverfc poiition,
with his belly on the edge of the bed^ and his feet
on the floor. According to Bajon, this variety,
which fcarcely ever proves mortal, continues feve-
ral months, and fonnetimes four or five. Towards
the end there comes on a pretty acute fever, with
an abundant fweat, and a cure is then effe(51ed.
Hippocrates confiders fever as falutary when it
takes place in this difeafe. {A^h. Ivii.yf^. 4.)

172. In America, the negro children who corTi-»
monly refide in huts badly Iheltered from the in-
clemency of the weather, and from fudden vari-
ations of the temperature, are very fubje^ to
this malady. It is much more common on the
borders of the fea, and in elevated places, than iq
diftri6ts fheltered by the lofty woods. To fecure
the children from it, they are kept in c|ofe warm
apartments, and frequently fubjet^ed to dry fric-
tion. This difeafe has become lefs common in
^t. Domingo fince the female negroes have been
made to lie-in in the hofpitals. It generally makes
its attack in the firlt nine or ten days after birth,
§n4 rarely beyon4 that period, Som^ are afFe6ted

CONVULSIVE AFFECTIONS. 3,g

-almoft the moment they come into the world, an^
die in a very fhort time.

The child jfirft experiences a difficulty of taking
the breaft, which it incefTantly quits and refumes ;
it continually emits difficult and plaintive cries,
and exhibits a ftiffnefs in the jaw, the neck, and
along the fpine. The n^ck remains ftraight ; but
the trunk becomes bent either forwards or back-
wards ; the mufcles of the limbs are lefs ftrongly
extended than thofe of the trunk; the compreffion
of the jaws becomes complete ; the tears and cries
decreafe. Irregular movements in the limbs, the
trunk, and jaws, llarting of the mufcles of the
cheeksare then obferved, and a (limy falivation takes
place. The fkin after certain intervals afTumes fome-
times a red and fometimes a violet tint. This difeafe
always terminates in death, and very often in the
courfe often or twelve hours; but, for the moft
part, towards the fecond, and fometimes not till the
tenth or twelfth day. In general, its progrefs is
flower, according as its attack commences longer
after birth.

173. A variety of this difeafe, characlerized by
a rigidity of the jaws, difficulty of fwal lowing, in-»
duration of the cutaneous tilTue, convexity of the
foles of the feet, and an apparent curvature of the
limbs, has been obferved in the Foundling Hofpi-
tal at Paris, It appears to have been produced
04 by

40 HISTORY 01? DISEASES^

by the impreffion of cold. {See Soc. Roy, de Med.
Sept emir e^ ly^J-)

The ufe of opium in ftrong dofes feems to have
been attended with ftriking fucceis in this difeafe*,
which is diftinguifhed by the name of Tetanus.

1 74. There is one general afFedtion of the ner-^
vous fyftem, which manifefls itfelf by alarming
iymptoms; it is always dangerous, and, for the
moft part, mortal. It is communicated by the faliva
of an animal in a ftate of madnefs brought into
conta(5]: with a part deftitute of epidermis. It is in
the faliva only that the infe(5lious quality relides ;
and animals who have died of this difeafe may be
touched with fafety.

In general, it is more to be apprehended that
infedlion will take place when the animal has bitten
a naked part, than when the wound has been in-
fli6ted through tbe clothes. It is probable, alfo,
that the ad ion of the faliva is ftronger or weaker,
according to the flate of the animal, which may be
either melancholy mad, or entirely furious. The
greater or lefs fenfibility of the perfons bitten, and
the particular (late in which they are, render them
more or lefs difpofed to be afFedled ; the power of
imagination, which heightens fear, and the dread *
of being attacked by fo horrid a difeafe, contribute

* Opium has been given in very large dofes in tetanic affeftions
without producing fleep..

. 6 alfo.

CONVULSIVE AFFECTIONS. 41

alfo, in a great degree, to aggravate the fj'mptoms.
The period between the time of being bitten and
the comnaenceinent of the difeafe is exceedingly
various : it generally takes place on the third or the
foarth day ; fometimes fooner, and at others not
till the end of feveral months j fome authors even
fay feveral years.

The commencement of the madnefs is always
announced by ibme phasnomena in the wounded
part ; the fear becomes red, or blueifh, and fome-
times opens and difcharges a reddifh lerous matter.
If the wound is not cicatrized, its edges are invert-
ed, the flefh fwells, afllimes a redder colour, and
furnifhes only reddifh and ferous mucus. The
fleep is then troubled, and agitated vi'ith ftarting
and frightful dreams ; the patient falls into a deep
melancholy, from which he cannot be roufed ; ex-
periences heavinefs and great depreffion ; heat
comes on from time to time, with fliivering, which,
commencing at the wound, is extended to the
whole body, and feems to terminate at the breafl
and the throat : the pulfe, in general, is fmall,
hard, and clofe.

At the end of three or four days all the fymptoms
incrcafe: the patient experiences pain in the head,
loathing, watchfulnefs, a general fenfation of lati-
tude, a painful conftri€tion at the breaft and throat,
which prevents him from f\valIowing ; refpiration is
difficult, interrupted by involuntary fobs and deep

' fighs ;

42 HISTORY OF DISEASES.

lighs ; convulfions, renewed by the leall: caufe,
from time to time take place. The patient, at
intervals, lofes his reafon, becomes furious, does
not know his nioft intimate friends, attempts to
bite them, and fometimes even tears himfelf. Every-
thing irritates and provokes him ; bright colours,
the fplendour of the light, the leaft motion, the
flighteil found, the agitation of the air, excite his
fury. Burnt up by internal heat and ardent thirft,
he is afraid to drink j the very idea even of water
makes him fnudder *. The face becomes red, and
the eyes haggard, fixed, and fparklingj he has an
air of ferocity, and at the fame time of fear ; the
voice is hoarfe ; and fpumous faliva flows from his
mouth. Retaining fometirnes his intelled^ual fa-
culties, he. remains peaceable, immerfed in deep
melancholy; is fenfible of his unhappy ftate ; fore-^
fees the return of the paroxyfms, and advifes his
friends to be on their guard. Sometimes he re-
mains in filent ftupor j at others emits loud cries
and dreadful bowlings. Sometimes he acquires

* The dread of water, and a propenfity to bite, ai^e fymptoma

not peculiar to this difeafe alone. An averfion to liquids has beeq

obferved in fome fevers attended with phkgmafia of the throat

or ftoraach, in fome cafes of hyfteric affeflion, &c. The furor

and irrefiftible propenfity to bite and tear, form the charafter of

certain kinds of mania ; it is fometimes feen during parou^yfrns of

epilepfy ; and thefe fymptoms are not always obferved in perfons

labouring ur\der canine rnadnefs ; v/e mj^y even fay thait tbey are

uncommon.

311

CONVULSIVE AFFECTIONS, 43

an extraordinary increafe of phyfical ftrength ; at
others is thrown into a ftate of the utmoft timidity,
a fort of lethargy or palfy. Trifmus, and a fpaf-'
modic tenfion of the mufcles of the belly, often
take place. Some experience a very painful pria-
pifm, accompanied fomctimes with ejaculation. At
length, after four or five days, the patient is
feized with extreme agony; his pulfe becomes
unequal and intermittent; vomitings, with a uni-
verfal cold fweat, come on, and he dies in coq-
Yuifions,

This difeafe is very rare : all the individuals bit-^
fen by mad animals do not experience the fym-
ptoms of hydrophobia ; and it is probable, that very
often after a bite by an animal fuppofed to be in
that ftate, nervous ()'mptoms, more or lefs ftrong,
produced by a fervid imagination, a fatal terror, or
the laceration of the parts, have taken place. It
jpnay be readily conceived alfo, that the faliva of
an animal irritated in a greater or lefs degree
may acquire a certain quality proper for exciting
fome flight fymptoms, which imagination and ter-
ror increafe, and perhaps render fatal. It is, there-
fore, of great importance, that a fufpe^ied animal
fhould never be killed until the nature of its ma-
lady has been accurately afcertained.

The carnivorous marnmalia are thofe only whicli
appear to be fufceptible of fpontaneous madnefs :
\\ip lierbiyorous are apt to receive it^, but have not

the

44 HISTORY OF DISEASES.

the power of tranfmitting it. It manifefts itfelf
particularlyamong dogs, during hot fummers and
very dry winters. This difeafe is afcribed, in ge-
neral, to the want of drink, and to extreme fatigue
while expofed to fcorching heat.

175. The fymptoms at firil obferved in a mad
dog are : fadnefs, dejection, a defire of folitude,
flartings at intervals ; tlie animal does not bark,
but often fnarls, and without any known caufej
refufcs food and drink ; his eyes feem dead ; he has
a wild look, ftaggers in walking, drags his tail be-
tween his legs, appears as if alleep, and obeys with
difficulty. At the end of two or three days he
does not know his mafter ; abruptly quits his habi-
tation, and wanders about with uncertain fleps, his
hair ereel, and his eye threatening, which is conti--
Dually in motion, or remains entirely fixed; his head
hangs down, his mouth remains open, and his
tongue, dependent, is covered with fpumous flaver.
Other dogs flee on feeing him. Sometimes he
{buns water, fhudders, and is irritated on feeing it ;
at other times he fwims acrofs it.

In this flate he attacks and bites, without di-
ftin6lIon, every perfon or animal that falls in his
ways it is then that his bite is exceedingly fatal ;
but, in general, after thirty or thirty fix hours he
dies in convulfions. The body foon pafies to a
ftate of putrefadion.

It

CONVULSIVE AFFECTIONS. 45

It-does not appear that canine madnefs ever took
place fpontaneOLifly in man*.

This difeafe, when once fully charadlerized^ is
conftantly mortal -f-.

After deathj no traces of alteration that can be
exclufively afcribed to the difeafe are obferved in
the organs ; which feems to prove that it conlifls in
a great perturbation of the nervous fyftem.

If canine madnefs confifts in a deranged move-
ment communicated to the a6lion of the nerves by
the poifonous faliva^ and if this movement, height-
ened by the fymptoms it produces, increafes fo far
as to annihilate'thc whole vital force, there is rea-
fon to believe, that the moft proper mean for op-
pofing the development of the malady is to imprefs
fpeedily a foreign a61ion on the whole fyftem, and
to maintain it for fome time ;|:.

Hence the utility of cauterizing the wound
flrongly with a hot iron, or cauftics, and of main-
taining in the part a violent and long-continued ir-
ritation. It is necellary alfo, at the fame time, to

* The reader, however, may fee two cafes of this kind by Galet
Dupleffis in the Mcmolrcs d- la Sac. Roy ah de Mklcdne.

t See the fingle cafe of Nagent, given alfo in the Memoires de
la Soc. Royals de Medeclne.

X C. Pmel learned from fome perfon who refiJed at Laiifanne
at the time, that Tiffot and Haller having caufcd a man labour-
ing under hydrophobia to be bitten by two vipers, a calmnefs im-
mediately toofe place, with a certain degree of infenfibility ; and
the wounds being afterwards drcffcd^ the patient recovered.

fupport

A6 tllStbRV op btSEASEg.

port the general energy by powerful ftimulants, and
in particulartooccupy the imagination, in orderthat
the perfon may entertain no fear of a certain cure.

176. There is another con vulflve affeflion which
manifefts itfelf by paroxyfms of iTiort diiration,fome-
times periodical, but, for the moft part, irregular.
It feems to confid in a fudden interruption of the
functions of the intellectual organ, and of the or-
gans of the fenfes, with a convullive movement of
the mufcles.

In many cafes the acceffion of this difeafe takes
place fudderJy, without any anterior fymptoms : it
is frequently announced by a peculiar fenfation, like
that of fome body moving, often from the extremity
of a limb, and gradually afcending, without exadlly
following the courfe of any principal nerve, as far
as the head ; after which the paroxyfm fuddenly
comes on. Sometimes the fenfation is like that of
a cold vapour, or fluid, running along, or of the
creeping of an infect ; fometimes the fenfation can
hardly be defcribed. In certain cafes, this fenfation
arifes from prcfTure, from the irritation of a nerve,
from a wound, a contufion ; but, for the moll: part,
no Isefion whatever in the part can be difcovered.

This movement may fometimes be interrupted
by ligatures, or by fire, occafionally applied. To
prevent an attack, and cure the difeafe radically,
extirpation of the part is recommended.

7 Indepen-

Convulsive affections. aJ

Independently of this vapour, which in certain
individuals always precedes, but for a very fhort
time, the paroxyfms. they are announced alfo, in
(bme, at longer or fhorter intervals, and fometimes
every other day, by nervous fymptoms exceed-
ingly various and inconftant : torpor, drowtinefs,
vertigo, fvvelling of the eye-lids, watering of the
eyes, tinging in the ears, rednefsofthe upper part
of the nofe, betvi^een the eye-brows, turgency of
the veins of the forehead, frightful dreams, agi-
tated fleep, violent pains in the head^ accelerated
pulfation of the temporal arteries, &c.

This difeafe exhibits numerous varieties, in re-
gard to the violence of the paroxyfms, and the
number and intenfity of the fymptoms. Some-
times the paroxyfm is a mere ftupor, a few mi-
nutes of vertigo, a fufpenlion, or at lead momen-
tary alteration, of the intelledlual fundions, with a
flight convulfion of fome particular part. At other
times the face becomes red ; the whole body is
ftifF, and fome convulfive movements are obferved
in the eyes.

For the moft part, a fudden and repeated aboli-
tion of the mental faculties of fenfation and volun-
tary motion takes place: the patient falls down,
and often with a piercing cry. In this cafe, ilrong
contortions of the limbs, of the head, and of the
trunk, are obferved, and generally ftronger on one
iidethan on the others diftorfion of the mouth, face,
and eyes; the tongue, which itTues from the mouth,

ia

48 HISTORY OF DISEASES,

isfubjeffl to be feverely wounded, and even cut, by
the convulfive collifion of the jaws; the pulfe is
fmall ; refpiration precipitate and irregular ; the
penis in a ftate of erection ; and the paroxyfm thus
pafles with conftant alternations of calmnefs and
new convullions.

After a certain period, a matter, commonly vif-
cid and fpumous, is reje6ied from the mouth. In
the flightefi: paroxyfms, a few bubbles only appear
towards the angle of the lips. Sometimes there is
alfo an involuntary evacuation of urine, of faecal
matters, and even of fperm.

The duration of the paroxyfrn varies from fome
minutes to about half an hour*.

Towards the end, the patient remains fome mo-
ments motionlefs, with the appearance of profound
lleep ; at length he fpeedily recovers, and often
gradually, both fenfation and mufcular fbrength,
without any recolleftion of the paft. The pulfe
and retpiration return to their ufual flate.

* I have feen a young woman between the feventh and eighth
rnonth of her pregnancy, who after a violent mental affcftion ex-
perienced headache, a fenfe of fufFocation, pain in the epigaf-
trium, and at length a fit of epllepfy, which continued fome mi-
nutes, and which left her infenfible, in a ftate of torpor and pro-
found (jeep. The paroxyfrn returned in an hour, with the fame
intenfity. This dreadful ftate of continual torpor and epileptic
fits, which recurred at the end of one or more hours, continued
thirty-fix hours, and was not removed but by the application of
twenty-four leeches to the temples.

After

CONVULSIVE AFFECTIONS. 49

After a firft paroxyfin takes place, it leaves be-
hind it fo great a fufceptibility, that the llighteft
caufe very often produces a fecond ; and it at length
appears, that there is eftablifhed a fort of habit
which renews the paroxyfms without the interven-
tion of any known caufe. Many variations occur
during the intervals between the paroxyfms. Some-
times the periodicity is very regular; but, for the
raoft part, there is no conftancy in the returns. It
appears, in general, that they follow each other
tjuicker, according as the difeafe is of longer Hand-
ing. Some have imagined that they could fometimes
difcover a certain relation between thefe returns
and the phafes of the moon. It is obferved alfo
that they take place, in particular, during fleep, or
immediately after awaking.

When the paroxyfms have recurred for a long
time, the difeafe often terminates by producing a
debility of the mental faculties. It gives rife to a
greater mobility, a more decided aptitude for all
mental afFedlions, joy, anger, &c. It occafions a
lofs of memory, and a ftate of ftupor, or even mad-
hefs*. It alters alfo the features of the face, en-
larges the inferior eye-lids, and the alae of the nofe.
After a flight or violent paroxyfm there fometimes
remain : deafnefs, blindnefs, paify. See. Sometimes
a flight paroxyfm is converted into apoplexy.

* Among two hundred maniacs C. PInel counted twelve or
fifteen epileptics.

VOL. III. ' E This

50 HISTORY OF DISEASES.

This difeafe is more peculi'ar to infanc}'', apd
even in the firfl: years of lifej to youth, to fe-
males, and in general to individuals of great ner-
vous irritability, who are as eatily animated by hope
as deprefled by fear ; who are moved by the flight-
eft affe6tions; and in whom the impreffions of for-
row, anger, or joy, excited by the moft trifling
caufes, fubfide with the fame facility. It attacks
plethoric perfons in preference to others.

It is often impoflible to determine the caufes by
which this difeafe is produced. The moft fre-
quent, however, are deep-roottd mental affei5lions,
violent'iri^VbnexpB^te4 impreiiions, great forrow,
feve^.'difappSirifment%:i.aSonifliing news, the de-
feat of @:gpr^ a.ftnang' lenfe of horror and aver-
fioia j- but, in particuMy a fright in infancy*.
ManyN4ti4iviiduals Is^^^^Joeen attacked by this dif-
eafe merely in comequence of having feen par-
oxyfms of it in others ; and this appears to arife^
from that irrefiftible propenfity to imitation which
is exceedingly ftrong in debilitated perfons. It takes
place alfo fomctimes after a wound or frafture in
the head ; a depreffion of the bones of the cranium ;
exceflive hasmorrhames, &c.

This difeafe, efpecially during the firlt years of

* In recapitulating the manlfeft caufes which Teem to have
produced the firft acceffion among the numerous epileptics of the
Hofpital de Bicctre, C Pinel obferved that tlic lall-mentioned
caufe was the moft common.

life.

CONVULSIVE AFFECTIONS. 51

life, may be produced by fo many caufes, that it is
difficult to afcertain whether children may not be
born with it. All tbofe almoll who experience fre-
quent paroxyfms during their earlieft years fall a fa-'
crifice to it before they attain to the age of puberty.
When it commences between the age of five and
ten, it may fometimes be cured. That which ap-
pears about the commencement of puberty (from
twelve to thirteen) without any manifeft caufe,
generally ceafes when puberty is fully ellablifhed.
Sometimes it is cured by marriage ; at others^
its fymptoms are increafed by it.

When it declares itfelf before the eftablifhmentj
or during a fuppreffion, of the menftrual flux, it is
always cured as foon as the flux becomes regular.
Though it comes on after puberty, it does not ap-
pear to be incurable. It feldom attacks old per-
fons i and thofe attacked by it at a younger age
are either cured or die before they become old.

On opening the body no organic alterations are

in general found, and even when laefion of the vil-

cera* occurs, it is often diflicult to conceive how

it could have been the caufe of the difeafe.

The

* There have been found in the head: carles of the interior la-
mina of the bones ;/^ exoftofis ; fharp offeous excrefcences, of
greater or lefs length, proceeding from different parts of the bafe
of the cranium, and penetrating the encephalic organ j an ulcer
in the membranes, the effufion of afiuid. In other parts : an ulcer
at the cefophagian orifice of the ftoraach, phlogofis, vibices, or

's. ^ " ' gangrenous

52 HISTORY or DISEASES.

The age, fex, and particular conftitution which
are mofi: fufceptible of this difeafe, and the caufes
by which it is moft frequently produced, feem to
indicate that it may be referred to a weaknefs or
too great irritability of the nervous a6lion.

Some examples are quoted, which feem to fhow,
that when a violent impreflion, ftronger than that
which produces the difeafe, and capable of break-
ing the force of habit which maintains it, is made
on the nervous {yUern, a cure is efFeded*j but thefe
particular inilances are not fufficient to eilablifh
any general precept for the treatment of this dif-
eafe, which has been diftinguifhed by the name of

• gangrenous fpots in the pharynx, the oefophagus, the flomach,
the Inteftinal canal, and in other places j biliary calculi j fcirrho-
fities in the fpleen, greater fluidity of the blood, flaccidity of the
folids, and a greater tendency of the body to putrefaftion when
the patient has died of a long continued paroxyfm.

* What Kaaw Boerhaave did at the Hofpital for Orphans at
Haerlem to check the progrefsof this difeafe, which was propa-
gated by imitation, is well known.

VESANIC

[ 53 ]
VESANIC AFFECTIONS.

177- The peculiar affections in which the intel-
ledlual fundions are eflentiaily deranged are ex-
ceedingly numerous and varied. They are never
obferved, in general, but in perfons who make a
bad ufe of the vital powers, and whofe intelledual
organ is habitually in a greater or lefs degree of
exaltation.

In individuals of a weak conllitution, when the
function of the intellectual organ is highly exalted
in regard to objects of the imagination, when the
action of the genitals is flrongly excited, when the
gaftric organs are continually overcharged with
too fucculent nourifhment, highly feafbned, and
almoft wholly digefbed, and when the mufcular
adion is annihilated ; this concurrence of cir-
cumftances, which forms fo (Iron g a contraft to the
mode of life for which man feems by his organiza-
tion to have been deftined, produces, efpecially in
large cities, a highly varied feries of phaenomena
of difeafe; but to give a detailed hiflory of them
would be tedious and difficult.

A great number of them, however, are compre-
hended under the two general forms which we are
here going to defcribe.

E 3 178. The

54 HISTORY OP DISEASES.

178. The firft often occurs in mature age, that is
to fay, between thirty and fifty. It is more common
among men than among women, is often hereditary,
and attacks in preference perlbns debilitated by ir-
regularities, or by long difeafes, thofe who lead a
fedentary life, and fuch as are addicted to too clofe
fiudy : it is in fome meafare the difeafe of men of
letters. It arifes, for the moft part, from a con-
currence of caufes, more or lefs multiplied, which
exercife a long continued action : excefs in the la-
bours of the cloiet, fudden tranfition from an ac-
tive to a fedentary life ; the abufe of narcotics; ex-
cefs in the pleafares of love ; fometimes from an
acute affe6lion experienced in the epigaflrium ; a
great fright ; deep grief; and in vi'omen, accidents
during pregnancy, or during parturition, &c.

A fingular atlemblnge of varied and extraordi-
nary fymptoms are then obferved to take place.
Thofc obferved in re2:ard to the mental faculties
are: unfteadinefs of character, ficklenefs of tem-
per, irafcibility, reftleffnefs, fadnefs, timidity, and
languor. The individual pays minute attention to
the ftate of his health ; every change of fenfation
makes him apprehend danger, and even death ; he
becomes unfit for labour; a derangement of memory
and tranfient delirium take place ; his fleep is dif-
turbed; he experiences pains in the head, vertigo,
confulion of fight, tinging in the ears, dullnefs of

hearing.

VESANIC AFFECTIONS. 55

hearing, an irregular fenfation of ardor in the
face, fudclen alternations of heat and of cold fweats.
Thefe fymptoms become exafperated at irregular
periods, and fometimes in a conftant manner after
meals : in general, the patient is much afFe6led by
every change in the ftate of the atmofphere.

The gaftric fyftem, in particular, exhibits varied
fymptoms of derangement : fuch as loathing, depra-
vation oftafle, naufea; irregular appetite, fometimes
none, and at others a voracious one ; tenlion and
heavy pain in the flomach, efpecially after meals j
bad digeflion, frequent vomiting, belching up of
burning and highly acid matters, hiccup, (hooting
pains in the abdomen, flatulencies, borborygmu?,
confiipation or diarrhoea.

Sometimes fwelling or even a very hard tumour
is felt tov^'ards the hypochondria ; the patient ex-
periences a fort of con{l;ri6lion at the breaft, op-
preflion, palpitation, irregular throbbing in fome
parts of the abdomen.

Thefe affecSlions, which often continue for feve-
ral years, occafion a flow and gradual confump-
tion, that in the end always becomes mortal.

Very often, on opening the body, no organic
alteration is obferved. A fcirrhus, however, is
fometimes found in the colon, an enormous fwell-
ing of the fpleen, ulcers in the pancreas, varices in
the meferaic veins ; and it is probable that thefe
derangements have at firft often been the confe-

E 4 qiience

56/ HISTORY OP DISEASES.

quence of a nervous affeclion of the organs of di-
geflion^ and that they have afterwards become the
caufe of a part of the confecutive accidents. The
aggregate of thefe fymptoms is generally diftin-
guiflied by the name of hypochondria/is.

179. The fecond form is met with, for the moil
part, among females, rarely among the other fex^
and chiefly among young women of an ardent
cohflitution, who have a ftrong propenfity to ve-
nereal pleafure ; among women of all ages who.
live in a ftate of voluntary or forced continence;
among young widows, who, fuddenly deprived of
the enjoyments to which they were in fome mea-
fure accuftomed, abandon themfelves to high liv-
ing, to indolence, to lafcivious ideas, and to the
reading of books calculated to excite them; among
thofe whofe menfi:raation is difficult ; in a word,
among all perfons who make a bad ufe of their
HJicllediual, digeftive, mufcular and generative
organs.

With thefe difpofitions, the fight of a handfome
young man on the ftage, or in a cheerful com-
pany, a diiappointment, a tit of paffion, peculiar
odours and favours, accidents during pregnancy,
and very often caufes which cannot be difcovered^
may produce the following feries of fymptoms^
which fometimes come on gradually, but for the
molt part by paroxyfms„

The

VESANIG AFFECTIONS. 57

The individual firfl experiences drowfinefs, agi-
tated fleep, intervals of fadnefs, aftonifhment, and
ftupidity, often accompanied with the effulion of
tears, or incoercible laughter, for whole hours. The
organs of the fenfes are in fuch a ftate of debiHty and
irritation, that they are painfully affected by a
ftrong light, a fhrill found, ftrong odours and fa-
vours, fudden touching, and every unexpedled
movement. The limbs remain in a ftate of torpor.
Sometimes a heavy pain takes place in the fore-
head, in the temples, and the eyes, with a confu-
lion of light, and, at intervals, aphonia. The pa-
tient experiences, in the left fide of the abdomen,
or towards the hypogaftrium, a pain and tumefac-
tion : a fenfation like that of a globular body mov-
ing in various dire61:ions, proceeds towards the llo-
mach, and gradually afcends thence to the larynx.
In all thefe cafes afpafmodic conjiridion is felt in the
throaty with a fort of fuffocation. A fpafmodic af-
fection of the inteftines is obferved, with borbo-
rygmi exceedingly noity, and very irregular agita-
tions. Sometimes tenfion and tightnefs of the
l^elly take place, accompanied with a conftric-
tio'n of the anus ; the urine is often abundant and
limpid ; refpiration, Ihort and precipitate, is per-
formed by ftarts ; at other times it is fufpended j
and in this cafe the pulfe becomes infenfible. Al-
ternations of rednefs and palenefs are obferved in
the face,- in fome cafes the vifageand neck are red

and

58 HISTORY OF DISEASES.

and fvvelled, with a (Irong pulfation of the arteries.
At length the trunk becomes ftifF, is twifted round
in different directions ; the limbs experience a
fpafmodic contraction ; a cold fweat is diffufed
over the whole body, and the patient remains in a
ilate of apparent death, which may continue forty-
eight hours, rarely more. Sometimes all thefe ac-^
cidents terminate in real death.

On the decline of the paroxyfm a gradual re-
turn of the natural heat, and of the ufe of the
fenfes, is effedled; the ilrength is progreffively
reftored, and the fpafmodic lymptoms at length
ceafe. Repeated fobs and fighs take place, with
flatulent emulations ; a relaxation of the genital
parts, and a difcharge of mucous matter. The
perfon awakes as from a profound ileep, for the
mod part with a pain in the head, and general lari-
guor, and a remembrance or no recolle6lion of
what occurred during the paroxyfm.

The intenfity and nature of the fymptoms, th?
alternation of fome of them with each other, their
greater or lefs exacerbation, their lono;er or fhorter
duration, produce all the varieties of this difeafe;
which may be more ealily conceived than de-
fcribed.

Very often, on opening the bodies, no organic
derangements of the abdomen are obferved : fome-
times, however, an alteration is found in fome of
the vifcera \ but in this cafe they appear to be ra-
ther

"VESANIC AFFECTIONS. 5^

ther the efFedl of the long feries of nervous affec-
tions which conftitiited the paroxyfms,. than the
primitive caiife of them*. It is, however, certain
that thefe derangements, when they exiti, mnft
afterwards render more conrrplex and increafe the
gravity of the fymptoms of this difeafe, which has
been di'ilinguifhed by the name o{ hyjierics,

180. Medicine has very little power over this
difeafe or the preceding ; or can only produce
fome flight remiffion in the paroxyfms. As thefe
affe6lions evidently arife from a bad ufe of the
fun<5lion of the intellectual, mufcular, digeftive,
and generating organs, they cannot ceafe till thefe
functions are employed in the proper manner:
hence occupations agreeable either in point of
tafte or of intereft, travelling, exercife faited to
the ftrength, wholefome nourifhment not too fuc-
culent, and which may afford occupation to the
flomach, moderate ufe of venereal pleafures, are
the only means of reftoring health.

* Vefalius often fouiid the ovaria larger than a tennis ball, and
filled wltll^ yellow liquid highly fetid ; Riolan found an ova-
rium indurated, and larger than the fill ; BInninger obferved a
lleatomatous ftate of the ovaria and the uterine tubes containiiig
a white, thick, and almoftfolid humour ; Diemerbroeck, a certain
increafe of fize in the uterus, and ayellowifh humour in its cavity;
Mager found the uterus voluminous, entirely ollified, and filled
with a whitlih, purulent, and fomewhat thick liquid, &c.

181. The

00 HISTORY OF DISEASES.

1 8 1. The intelledlual organ is fometimes de-
ranged in confequence of the too great aftion ex-
crcifed on it by the uterus, or of the reelprocal
a6lion of thefe two organs^ which mutually exalt
each other.

In young women of premature paflions, who are
deeply in love, and whofe inclinations have been
thwarted by infarmoun table obftacles ; in debauch-
ed females, efpecially when fuddenly torn from
their antient habits by forced feclnfion j in ardent
females united to cool hufbands infenfible to the
enjoyments of love, or whofe weak conftitution
commands temperance; in young widows fud-
denly deprived of flrong and vigorous hufbands,
in their intercourfe with whom they had acquired
the habit and need of pleafure, and the remem-
brance of which occafions bitter regret^ when thefe
firft difpofitions are much increafed by forrow and
difappointment, by reading lafcivious romances or
poetry, or looking at lafcivious pidlures, with which
their imaginations are continually heated ; by the
life of fucculent, delicate food, generous wines,
ftrong liquors, idlenefs, and particularly a habit of
folitary pleafures, a feries of very extraordinary fym-
ptoms fometimes takes place.

There is firll obferved a Angular inclination to
diredl: the converfation to one favourite fubje6l;
rreat languor and ennui when it turns on any thing
©Ife ; a great readinefs to liften to flattery ; an

8

VESANIC AFFECTIONS. Ql

averfion to all occupations, even of the eafieftkind.
Thefe phEenomena are foon fucceeded by dejedlion,
uneafinefsj a love of repofe, folitude^ and filence.
All the thoughts are entirely confined to obfcene
obje6ls ; appetite and fleep are both loft. The in-
dividual becomes fubje<5t to inordinate defires^ of
the turpitude of which fhe is fully fenfible ; fhe
makes efforts to retiirn to a ftate of reafon, or at
leaft to conceal from others her condition ; fhe
even hopes to be able to conceal it from the per-
fon who is the caufe of it.

Soon after the becomes entirely abandoned to
lafcivious thoughts, which fhe defpairs of being
able to refifl ; a laft attack is made on modefl:y,
which is now compelled to yield ; the flrength is
exhaufted; deep melancholy comes on, and effron-
tery alTumes the place of decency. The leaft flat-
tery is received with an impaffioned tone of voice
and geflures ; (he is lavifh of her careffes, prayers,
folicitations, and even threats, to induce the firfl
perfon fhe meets to gratify her defires ; and if he
refifts, fhe infults him with the mofl calumnious
reproaches, and befiows on him every opprobrious
name that anger and revenge can fuggelt.

At length a complete alienation of the mental fa-
cullies is announced by difgufting obfcenity, cries,-
tranfportsof paflion, lafcivious gcdures, an afFefta-
tion of nudity ; all males are folicited, urged, and ^
followed with a blind fury, and beaten or torn if they

refifl.

62 HISTORY OF DISEASES.

refifl. The patient experiences continual watch*
fiilnefs, an univerfal burning heat, without fever or
thirft ; inlenfibility to the moft fevere cold.

In all thele periods, but particularly the third,
there is often experienced a very diilreffing itch-
ing towards the vulvo-uterine conduit and the
uterus. Thefe parts, which are fometinaes in-
flamed, excrete a thick, vifcid, fanious liquor, and
the clitoris becomes lengthened or tumid. In
this cafe, on opening the body, there are found an
ulcer in the uterus, Iwellingofthe ovaria, &c.

This peculiar alienation, known under the name
of the fiymphomania, belongs, in a great meafure, to
moral medicine. '

182. Men are fbmetimes fubjeS: to a dlfeafc
which has fome refemblance to the nymphomania.
It announces itfelf by an infatiable defire for vene-
real pleafures, while ere(51ion is neither weakened
nor diminifhed by enjoyment. A general fpafm or
tenfion prevails in the groin, with pain in the ge-
nitals, an itching or titillation in the fides and arm-
pits ; the face is red, and covered with fweat j
the patient bends his body, fqueezes his belly with
his hands, and falls into a ftate of fadnefs and de-
jeftion. The progrefs of the difeafe is announced
by obfcene difcourfe, indecent adlions, lafcivious
motions, and an impoffibility of reftraining them.
The patient, much altered, has a horror of food,

VESANIC AFFECTIONS. ^3

devours it with avidity ; he vomits up a vifcld
matter, and foams at the mouth, like a Hag in rut-
ting-time.

If the termination becomes fatal, a painful ten-
iion is obferved in the abdomen ; a ftifFnefs or con-
tra6lion of the limbs ; bodily motion is difficult;
the pulfe is fmall, weak, and irregular ; and the
difeale, become exceedingly rapid, may produce
death in feven days. A cure is fometimes pro-
duced after abundant mucous or bilious ftools, and
vomiting of the fame nature.

This difeafe, called fa Pyriq^s, is more common
in warm countries, at the period of adolefcence,
and among individuals who have a ftrong propen-
fity to venereal pleafures. Aretasus, from whom this
defcription is borrowed, appears to have had fome
opportanities of feeing this afFeclion. He lived in
a warm country, and among the Greeks^ a people
who fcem to have carried to the utmoft extent
every thing that could inflame the imiagination,
and raife it to the higheft degree of exaltation. In
our climates this difeafe is uncommon.

183. The intelle6lual function, without appear-
ing to be totally deranged, often exhibits evi-
dent characters of exaltation, weaknefs, and very
great mobility, which conftitutes a particular ftate,
which we are now going to defcribe.

During the firft period it announces itfelf by ha-
bitual

^4 HISTORY OP DISEASES.

bitual ladnefs, irafcibility, and watchfulnefs. The
patient afterwards becomes fubjed to continual
fears and fudden terror; his flcep is difturbsd by
frightful dreams. He is rendered uneafy by the
leafl trifle; falls into violent fits of paffion, fol-
lowed by fpeedy repentance; exhibits traits of for-
did avarice, and afterwards of the mofl lavifh pro-
digality ; a taciturnity, interrupted fometimes by
buriis of convulfive laughter; and, in a word, every
thin^ that cbara6lerizes the utmofl ficklenefs and
ineonftancy.

During the further progrefs of the difeafe, h^
entertains continual fufpicion and fear of poifon ■
his terror is every moment renewedj with conftant
hefitation, averfion to mankind, abje6lion, love of
folitude, whimfical, fantaflical, and fiiperftitious
ideas 5 ridiculous complaints, wild flights of the
imagination ; the delirium is fixed to one objedlj,
which the mind purfues with the moft ardent per-
feverance; and this delirium carries to the utmoft
degree of exaltation the aiFe6tions which it pro-
duces. Sometimes the patient fhows a deter-
mined difgull to exiftence, and an irrefilitible pro-
penfity to fuicide. This ftate is often the e£Fe61
of an exaggerated idea of the misfortunes of lifcj of
difappointment, and forrow : at other times it
feems to __be the refult of too advantageous a fltil-
ation in point of fortune, which places the indivi-
dual in a flate where he has nothing further to

hop^.

VESANIC AFFECTIONS. ^$

hopCj or to fear ; which prefents no obflacle to be
furmounted, and affords no field for new enjoy-
mentSi

Independently of thefe fymptoms, or of others
eqiiall)/ lingular^ fome inciividuals exhibit an ex-
alted fenfibility, fometimes perverted, and irregular
returns of fpafms or convulfions, with an habitual
delirium more or lefs flriking. Thefe paroxyfms,
fufpended fometimes by other difeafes, re-appear
during convalefcence ; they terminate fometimes
in mortal fpafms, and at others in general con-
fumption. '

Thefe fymptoms of alteration chiefly afFe6l per-
fons who have a peculiar conflitution of body and
mind: fuch as a meagre and withered appearance;
pale, leaden, or yellowifh colour ; harfh and for-
bidding gravity; chara6^er unequal and capricious;
fquinting look, ftudied referve, ferious and thought-
ful mien ; air of timidity and circumfpedlion, diffi-
cult temper ; good appetite, but attenuation by
watchfulnefs ; fometimes abftinence through the
fear of poifon, withering and drying of the body,
premature old age ; morofenefs ftrengthened by
the progrefs of years.

This, ftateis remarked, for the moft part, in tl]p
age of virility ; it commonly begins in the fummer
and autumn, and ends in the fpring. It is pro-
duced by a concurrence of caufes highly various,

VOL, III. w , as :

66 HISTORY OF DISEASE^.

as : exceffive fludy, religious fear, violent or un-
fortunate love, profound grief, reverfe of fortune,
the abufe of intoxicating narcotics, folitude, the
interruption of an active life, idlenefs, luxury, efFe-
minacy, and fatiety of all the pleafures of life.

This Itate does not render confinement necef-
fary, or produce a profound and acute alteration,
which foon brings on death, or flowly terminates
in real confumption. This afFedlion is often cured
by a reverfe or an amelioration of fortune, a pow-
erful diftradion, and by every thing that can ex-
cite a lively intereft beyond the ordinary habits.

This difeafe, the aggregate of the lymptoms of
which conftitutes melancholy, fhows a great relation
to that which remains to be defcribed, and with
which it is often confounded.

184. In a great number of alterations of which
the intelledual functions are fufceptible, the moll
ftriking iymptoms of derangement come on inftan-
taneoufly by fits: their return, for the moft part,
is irregular, and fometimes periodical.

Mania, whether during the paroxyfras or dur-
ing the ftateof calmnefsj prefents itfelf under dif-
ferent forms, which depend on the mode of alter-
ation in the fundlion of the intellectual organ.
In general, the violent paroxyfms are never of
long duration ; they always terminate, at the end

of

VESANIC AFFECTIONS. 6/

of a longer or fliorter period, by a fort of calm, or
milder mania : others exhibit a conftant ftateof in-
fanity, or abfolute idiotifm.

On the approach of a paroxyfm of mania, the firfl:
effeS. which rcfults from the derangement of the
cerebral organ manifefls itfelf, in particular, to-
wards the abdominal region. A confliridion is
obferved of the epigaflrimn ; loathing of food, ob-
fttnate collivenefs, fenfation of burning heat in the
inteftines, then in the breaft, and at length in the
face, with a deiire for cooling liquors.

Soon after, the individual exhibits extraordinary
gefiiures, with lingular looks and movements.
Sometimes there is an elevation of the head, with
the eyes fixed on the heavens ; the lunatic fpeaks
with a low voice, walks about, fuddenly flops, with
an air of admiration, or of profound recolleclion.
Sometimes he indulges in excefs of mirth, mani-
fellcd by immoderate burlls of laughter ; at other
times he falls into profound lilence, accompanied
with an efFulion of tears, great fadnefs, and ex-
treme anguifh. Very often he exhibits fudden al-
ternations of immoderate joy and of the deepeft
grief. In certain individuals, the eyes almofl; of a
fudden become fiery and fparkling, and the cheeks
colouredi which announces the neceffity of fpeedy
confinement. In others, a fudden and incoherent
flow of words is obferved, with frequent fits of
laughter, torrents of tears, and foon after fury, and
F 2 an

63 llISTOlli' OF DISEASED. .

an irrefiftible propenfity to violent and fangillnary
adlions. In almofl all maniacs a fort of tranfient
efFervefcence, and a real exacerbation, take place on
the approach of ftorms, or in confequence of a very
warm temperature of the atmofphere. They are
then feen to run along with precipitate fteps, de-
claiming without order or connection ; falling into
a violent rage, without any caufe, or on the
flighteft provocation, emitting loud and confufed
cries.

The paroxyfms of religious mania are often pre-
ceded by ecftatic vifions. Thofc of mania from
love are preceded fometimes by enchanting reve-
ries, and a fuppofed appearance of the beloved,
object.

Mania, in general, manifefls itfelf under the ap-
pearance of a continued tranfport of anger more
or lefs impetuous ; and it is much better charac-
terized by thefe emotions of an irafcible mind,
than by confufed or whimiical ideas.

Some maniacs fhow a wonderful confi:ancy and
facility in enduring the mofl rigorous and long con-
tinued cold; fomeeven experience an evident enjoy-
ment by the application of ice to the epigaftrium j
but in many cafes their fenfibility for cold is exceed-
ingly great, and inftances of the hands and feet of
fome of them being frozen have at times otcurred.
Some remain obftinately awake. In mofl: of them
& nervous excitement, marked by a confiderable

augmen*

VESANIC APPECTIONS. Qq

augmentation of raufcular force, with a ftrong
convidlion that nothing can refift them, takes
place ; they then difplay the utmoft intrepidity,
and give full fcope to the moil extravagant ca-
prices.

On many occalions they refufe all nourifhment
for four, five, and even for fifteen days, provided
they are amply fbpplied with drink. On the other
• hand, they often experience a mofi fingular vo-
racity, and fpeedily become faint when deprived
of the ufual quantity of food.

Warm feafons have a firiking influence on the
return of the pqroxyfms, the duration of which is
pretty generally confined within a certain period
of from three to five months. They commence in
that which follows the fummer folftice, continue,
^ith more or lefs violence, during the beats, and
terminate towards the end of autumn. In fome
maniacs, however, the paroxyfms renewed at the
end of autumn are continued throughout the win-
ter, with remifiions or exacerbations according to
the degrees of cold. Some cafes have occurred
alfo, where the paroxyfms taking place in fummer
have been renewed on the commencement of the
cold weather. It may be readily conceived that the
following caufes muft contribute to the renewal of
the paroxyfms : tranfports of paffion excited ; the
prefence of objedts calculated to revive in the mind

r 3 the

70 HISTORY OP DIS*EASES.

the original caufe of the madnefs ; the abufe of in-
toxicating liquors, forced abflinence from food, &c.

But fome paroxyfms are renewed at fixed pe-
riods, without feeraing to be determined by any
"known caufes*.

Mania prefents itfelf under different forms, ac-
cording to the nature and intenfity of the derange-
ment of the intellectual fundlions. Thefe different
forms may be arranged under the following four '
principal heads :

ift. Weaknefs or exaltation of the hit ell eSlual fa-
culties. The individual, in this cafe, difplays great
levity, flupid abfence, impoflibility of keeping the
mind fixed a few minutes on the fame objeCf ; lin^
gular inconfiftency and giddinefs ; continual mo-
bility, attention to childifh occupations, weaknefs
of memory, fudden flights, loquacity or tacitui-nity,
a rapid feries of incoherent ideas, premature do-
tage; and fometim.es incoercible tranfports of
paffion, ariUng from the nature of the organiza-

* At the Bicetre a maniac every year experienced an attack
which lafted three months, and which terminated towards the
middle of fummer. Another was feized with a paroxyfm every
two days in three, being always one day in a ftateof tranquillity.
A third was in a ftate of the mofl; furious madnefs for fifteen
days, and then remained in perfeft calmnefs eleven months and a
half. Three others continued eighteen months without any con-
fufion of ideas, or wildnefs of imagination j but for fix months
after that period they were raving mad,

tion.

VESANIC AFFECTIONS. 71

»

tion, or a vicious education. During the par©x-
yfms there are frequently obferved an exaltation of
the ihtelle6lual faculties, great fertility of imagi-
nation, a fort of infpiration and enthuiiafm for the
greateft virtues, public and private.

2d. Partial or injiantaneous aUeration of the in-r
telleSlual faculties. In this cafe the imagination is
exalted in an extravagant manner, or ftrongly im-
prefled with fome erroneous idea ; the fenfes feem
to receive the impreffion of obje^ls which do not
cxifl*: in other refpe6ts the judgement is found,
and the ideas coherent, even in regard to the erro-
neous object. Childifh fear is often obferved, with
great timidity ; and the utmoft miftruft, which in^
duces the individual to refufe every kind of food,
and to remain awake ; alfo fanaticifm, and fond-
nefs for the marvellous. During the parox^fms,
the deranged movement and con fu fed agitation of
the brain excite a propensity to deflruclive and
even to fanguinary a(5i;ioris. Some individuals then
imagine that they have an irreliftib.le delire to com-
mit murder, confirm themfelves in this idea, iand
deplore their condition -j".

3d. Com-

* Frequent inftances of this kind may be found in myftic \i*-
fionaries, and perfons who imagine they every where fee poifon,
monfters, ferpents, &c. ; who think their legs are of wax, qr-
tb^j: pofteriors of glafs 5 who believe thenrfelves converted inta
gnimals, prophets, deities, &c.

f C. Pinel, io his ingenious work on madnefsj^from which wc
F i^ have.

72 HISTORY OF DISEASES.

^d. CompJele alteration of the intelleBual faculties^
In this cafe, the individual betrays a want of judg-
ment in regard to all obje^ls, accompanied with
aberration of memory. This ftate affedls different
forms: the mania often feemsto confift in, a ftrong
nervous excitement, a turbulent reftlefFnefs which
admits of no repofe ; agitation^ cries, fparkling
appearance of the eyes, obftinate watchfulnefs^ fu-?
periority of phyfical firength^ ardour- for venereal
pleafure \ a blind tendency to derange, break, tear^
and deftroy every thing, and even to commit fan-
guinary adiions ; delirium of happinefs and joy,
illuiions, extravagant flights of pride, in thofe who
fuppofe themfelves to be generals, prophets, and
deities ; fantaftic viiions. The maniac imagines

have taken tlie materials of what has been here faid on this fub-
je£l, is of opinion that the functions of the luill are difanct from,
thofe of the underfanding; which is contrary to the opinion gene-
rally eutertained refpefting the analyfis of the intelleftual func-
tions. He gives the hiflory of a lunatic whofe periodical mad-
nefs was announced by the mofi: fanguinary fury, which the. indi-
vidual faid he was not able to reftrain. During his lucid interval?
he deplored his miferable ftate ; continually fpoke of it, and be-
came more and more confirmed in the idea that he had an irrefift-
ible propenfity to murder : but this ftate was, no doubt, the
ftffeft of a deranged inteile£t, and it is not more extraordinary to,
fee a maniac with a perfuafion that he has an irrefiftible propen-
iity to fanguinary a6tions, than to fee another impreiTed with a
belief that he is a prophet or a king. In our opinion, this kjnd
of maduefs may be affigned alfo to the province of moral me-
dicine.

TE3ANIC AFFECTIONS. 73

he every where fees daemons, ferpents, poifon ; has
a rapid fucceffion of ideas whicbfeem to arife from
the firong excitement of the brain, without any
relation to the impreffions made on thefenfes;
with exuberance of words; tirefome loquacity;
continual fucceffion of incoherent ideas ; tumul-
tuous concurrence of different affediions and fen-
fations, of joy, iadnefs and anger.

4th. Annihilation of the mental faculties. In this
cafe are obferved ; an inanimate figure, air of
idiotifm, habitual fl:upor, infuperable ina6livity,
-automatic motions ; foolifh and filly laughter, con-
tioiial filence, or a few inarticulated founds; life
merely aninnal ; no memory j the ideas and lan-
guage confined to objecls calculated to fatisfy the
pommon neceffities of life.

In maniacs who have been expofed to violent
^nd long continued paroxyfms, there are obferved,
at the period when thefe paroxyfms terminate (for
the moft.part towards the end of antumn), great
vveaknefSi a fenfation of general Iafiitude,a faintnefs
which often produces fyncope, great -corifufion of
ideas; fometimes a real flate of ftupor, and almoft
of infenfibility, with morofenefs of temper and
deep melancholy. The unfortunate individual re-
mains in bed, flretched out motionlefs, with the
features altered, and a weak deprefled pulfe. In
this iiate of atonia he runs the rifk of periiliing,

efpeciaUy

74, HISTORY OP DISEASES.

efpecially if the cold be fevere, and unlefs the vital
heat be maintained by cordials and the accumula-
tion of bed-clothes.

Obfervation induces us to clafs among thofe
fubjccl to mania, perfons who fhow an ardent ima-
gination and great fenlibility, energetic paffions,
and the mod eftimable moral virtues. This affec-
tion takes place equally at all ages. It is much
more .frequent among vi^omen than among men,
and fcarely ever is obferved among thofe who cul-
tivate the exadl fciences.

According to information acquired in regard to
the former ftate of maniacs, it appearsthat we may
coniider as the moft common caufes of this difeafe :
a violent and unfortunate paffion, inordinate am-
bition, reverfes of fortune, fanatical devotion, the
delirium of ardent patriotifm. Aretasus includes
alfc too liberal facrifices to Bacchus and Venus j
and among the women, forced abftinence from
the enjoyments of love, he,

But, in general, there exifls no conftant rela-
tion between the type, the fpecific chara61:er, or
the intenlity of the mania, and the caufe or na-
ture of the objedl which has primitively given rite
to it. Thefe variations fecm. to depend more on
the degree of fenfibility of the individual, and on
numerous fortuitous caufes which affe6l his in^
telle6lual organ, exalted or Vvcakened. In gene-

raL

VESANIC AFFECTIONS. 75

ral, a more irafcible difpolition, and tranfports
which often border on raadnefs, are obferved
among, thofe vigorous men, whom Cabanis de-
fcribes with fo much truth and energy in the fol-
lowing iketch*:—" Bolder and more ftriking
looks, fparkling eyes, a dry and often yellov/ vifage,
jet-black hair, fometimes frizzled j ftrong limbs, but
is/ithout corpulency ; great mufcularftrength though
in appearance llender; a meagre body, and pro-
jelling bones; ftrong, hard pulfe. Thefe men,"
fays the author, " are continually hurried awaj
by the torrent of their imagination and paffions.
They wifli to carry every thing by force, violence,
and impetuofity." On the other hand, more mo-
deration is obferved in the mania of perfons with
ehefnut-coloured hair, and of a mild and moderate
character. Among fuch perfons, in particular, it
is found under the appearance of a calm and peace-
ful reverie, which often terminates in idiotifm, or
3 fort of imbecility often incurable.

Mania does not feem to arife from any known
derangement of . the cerebral organ. The bodies
gf maniacs, when opened, rarely exhibit any traces
of very evident alteration in the brain. This dif-
eafe feems rather to conlift in a diforderly move-
ment, a weaknefs or too great mobility of the
uervous adtion ; a real alteration in the intelle6lual

* Memoires de I'lnftitut, an. vf,

fundlions ;

*rQ HISTORY OF DISEASES.

functions ; and it is proper to fee, with Stahl, fince
imitated by Pinel, in the development and progrefs
of the paroxyfms, all the phsenomena of falutary
rea6lion. Vv e indeed obferve : abdominal fpafms,
coloration of the face, accelerated circulation, ex-
alted energy of the mental and bodily powers; the
excitement of blind impetuofity, incoercible agita-
tion. The underil:anding is hurried away by thc5
force of thefe combined movements ; and after a
certain duration, the extent of which is variable,
there come on : a diminution of thefe phssno*
mena, a depreffion of all the faculties of the indivi-
dual, a progreliive return to reafon ; and the cure,
in general, is the more probable as the paroxyfni
has been more violent. It feems to be proved by
obfervation, that of all the varieties of mania the
moft obftinate are thofe which exhibit pure idiotifm,
the imbecility and flupidity of the Cretins ; that we
nDuit place in the next clafs continued mania,
which does not prefent any ftriking exacerbation %
in a word, that the hope of cure is at the higheft
degree in periodical mania, and particularly in in-
dividuals from the age of eighteen to that of
twenty-five, v/ho pofiefs the greateft force of
nervous rea61ion. Inftances of cure at an ad-
vanced age rarely occur ; as if a fhock fo violent
were above the powers of nature after the pe-
pod of the greateft vigour. Sometimes the par-
oxyfms

VESANIC AFFECTIONS. 7^

exyfrns gradualiy increafe, and at length become
mortal.

185. Will it Hill be the pra6iice to employ in-
difcriminately bleeding, bathing, camphor, opium,
&c. in the treatment of mania, notwithflanding the
bad effe<5]:s which they are daily known to pro-
duce ?

" Madmen muft not be confidered as entirely
deprived of reafon, and as inacceffible to every
motive of hope or fear ; to every fentiraent of ho-
nour. They muft firft be fubdued, and then en-
couraged." Bihliotheque Briiannique, vol. viii.

Tdconfole lunatics, to fjjeak to them with kind-
nefs, to avoid by evafive anfwers a refafal. which
might irritate them ; to overcome their obftinacy
by inflexible firmnefs, without any a6l of violence;
to guard againil exceflive complacency as well as
ill-timed contradiction ; to infpire them with falu-
tary fear, but always connected vv'ith a fentiment of
efteem ; to remove every circumftance that might
recall to their minds the primitive caufe of their
madnefs, and which confequently might produce
an exacerbation, or perpetuate its duration : fuch,
perhaps, is the fum of the general means afforded
by what may be called moral regimen. But the
firft of all, no doubt, is to remove the lunatic from
his ufual refidence, from the bofom of his family,

where

78 HISTORY OF DISEASES.

where he might be conflantly fiirrounded by ob»
je6ls connedled with all his habits, and from per-
fons whole prefence might continually remind him
of his misfortunes, of the caufes of his unhappinefs^
Sec. none of whom could fecond the exertions of
the phyfician, and much lefs acquire Over the ma-
niac, in an efFetlual manner, that abfolute empire
which commands obedience. It is, therefore, in-
difpenfably nccelTary, that fuch perfons fhould be
,conveyed to public eltablifhments, where the bell
poflible means are provided for putting in praflice
ihis mode of moral treatment : fuch as very fpa-
cious, folitary, and well fecured accommodations,
where the maniacs when attacked by the par-
oxyfms may be feparated, and be thus prevented
from irritating each other, or from dilturbing
thole who are in a flate of convalefcence ; and
where they may be carefully watched under the
infpedion of men who have acquired by pra6lice
the proper methods of reftraining lunatics with-
out violence, and without danger to them-
felves.

Bat when it is known that moft of the public
hofpitals for the reception of lunatics are ella-
blilhed on the fame plan, and adopt the general
method of fubjedting them to a uniform mode of
treatment, by employing bleeding, the cold bath,
and pretended calmers ; and that others are pro-
vided

VESANIC AFFECTIONS. 7g

vided for receiving them afterwards as incurable,
and for locking them up like fo many favage ani-
mals, it may readily he conceived how far fuch
eftablilhments fall fhort of the perfc6lion to which
they might be carried in confequence of the en-
lightened ftate of the prefent period.

RECAPI-

[ 80 ]

KECAPITULATION

THE HISTORY OF DISEASES,

WITH

VARIOUS REFLECTIONS,

1 86. A MINUTE hiftory of the numerous dlfl
eafes to which man in a ftate of fociety is fubjedl,
and a knowledge of the caufes by which they are
produced, evidently prove that the whole of them
almoft have had their origin among individuals
crowed together ; and that they are the refult of
local influence, of the manner in which people
are lodged, clothed, and fed, and of the varied em-
ployment of the different fundlions.

The human race are not fubjedl: to more dif»
eafes than the other animals ; and every well-or-
ganized perfon who refides in a falubrious coun-
try, who enjoys a fufiiciency of wholefome nou-
rifliment, who makes a proper ufe of his fun6lions,
and who is fecured from every accident, experi-
ences no difeafe, and dies of old age.

Man in the favage and hunter ftate exhibits the

type of the moft energetic organization. Being

continually employed in exercifes -which call forth

6 his

REFLECTIONS ON TitE HISTORY OP DISEASES. 8i

his flrength and agility, and fed on the f]e(h of the
animals he has caught, he finds himfelf under the
two circumftances nioil favourable for acquiring an
athletic conQitutiorii

Though man, in confequence of the general;
conftitution of his digeftive lyflem, is polyphagoils, -.
animal food is that moll agreeable to him^ and the
kind which he naturally prefers. The carnivorous
favage acquires thofe habits of cruelty which are
the neceffary refult of his mode of life^ and which
are found among all animals that^ like him, feed
on the produce of the chace.

Ichthyophagi, fuch as are the greater part of the
Finns, exhibit an organization much lefs robuft ;
they employ patience and dexterity, father than
ftrengttf and courage, to catch their prey^ and their
food is lefs nourifhing and lefs falubrious.

Nomades, employed alone in guarding the herds
and flocks which fupply them with a milk diet,
fuch as the fmall number of Tartars, who abftairi
from flefh, do not polTefs that ftrength and dex-
terity acquired by the exercife of hunting ; and in
the wars carried on againft them by the hunter
hordes, they always Ihow a very great inferiority 2
in a word, confidering the exercife they take,
milk to them is a fufficient and proper nourifli-
ment.

In the laft place, thofe who live on|y on vegeta*
bles, like the Indians, exhibit, at the fame degree

VOL. Ill, Q of •

82 REFLECTIONS ON THE

of civilization, weaker conftitutions and mildef
manners.

In thefe different ftates of ftrength and energy,
if men are not crowded together in too great con-
fufion; if they refide in temperate climates, habi-
tually dry and free from marOiy exhalations, they
all enjoy perfedl health, and arrive almoll uni-
formly at death by old age.

Bat, in proportion as men unite in fociety, dif-
ferent difeafes, to which they afterwards remain
fubje6l, are developed amongft them.

187. Scurvy is one of the affe6lions firll ob-
ferved amon^; riverian people, or thole who in-
habit countries partly covered by Vv'ater.

The continued adlion of cold moiftur^^ debili-
tates their nervous llrength, and produces in them
a fort of death at the furface of their bodies; the
ildn grows pale, and' is covered with livid fpots ;
exudations take place in the cellular tifllie ; it be-
comes choked up, or decays ; the gums fwell, and
are ulcerated ; they experience pains more or lefs
acute, their limbs often fhrink, and they perifh in a
fort of confumption.

Men are the lefs capable of refifting the influ-
ence of this humidity the more they are weakened
by reft or fatigue, by the vi^ant of nourifhment, by
the bad quality of their food, and by all thofe
caiifes which tend to debilitate.

That-

HlStORY OF DISEASES. 83

That weak and debilitated conftitution which
produces fcurvy is afterwards tranfinitted, in part,
by generation.

The fatal influence of continual humidity in a
cold marfhy country may, in a great meafure, be
corrected by human induftry : hence, to dig canals
for the purpofe of giving motion to the ftagnant wa-
ters ; to provide elevated habitations, better cloth-
ing, found nourifhnnent, alcoholized beverages; to
pay attention to cleanlinefsjand ufe proper exercife,
are the beft means for preventing, almoft entirely,
fcorbutic afFedlion in the dampefi; countries, as may
be fecn in Holland. It is by employing a part of
thefe means that navigators are enabled to prevent
the fcurvy on board fhip during long voyages.

W^xm-blooded animalsj and even a great num-
ber of plants, experience affections analogous to
tire fcurvy, by the continued atftion of exc^ffive
moifture*

i88. In the infancy of fociety, when men, as
we may fay, are wanderers on the earth, without
proper habitations; continually expofed to the in-
temperance of the feafons in different climates;
forced to an incetlant adiivity to infure their fafety
and to provide for their wants, the organization
becomes habituated to the impreffion of heat and
cold, drynefs and moifture.

The fkin, by its continual expofure 'to the air,
G 2 and

84 REFLECTIONS ON THE

and by fucceffive fridlion againft different bodies,
becomes indurated. The mufcular fyftem, by va-
ried and extenfu'e exercife, acquires great force j
and the lungs are habituated to inhale atmofpheric
air at different degrees of heat and moifture. The
fiiomach receives coarfe aliments, which require
great labour to be digefled ; and it can bear
without difficulty either an excefs of food or long
falling.

In a word, a being who is thus continually fti-
mulated by abrupt and frequent changes of his con-
dition, and who isnot fubje^tedto the influence of
any habit, acquires a conliderable force of organi-
zation. In this ftate blows, falls, privation of every
kind, heat, cold, and humidity, though carried to
a very great degree, produce only very flight in»
difpofitions. Every part poflefles a firong power
of reaction; and all thefe organs, fo fine and fo de-
licate, which feem fo eafily deranged, form by their
pliability and adion a whole capable of refilling
the moil powerful caufes of deftrudion-

189. On the other hand, at a degree of civili-
zation pretty far advanced, when men united in
cities begin to have well built habitations which con-
tinually fhelter them from the injuries of the air^
when their ildn is fecured by good clothing from
the contaft of exterior bodies, and from the im-
preflion of cold and dampnefs j when habit or do-

medie

HISTORY. OP DISEASES. 85

meftic occupations withdraw them from the influ-
ence of atmofpheric variations, their parts acquire
a great fufceptibiHty for being affedled by every
abrupt change. Their organization does not
poflefs that power of readlion which oppofes the
firft caufes of derangement, or which fpeedily re-
moves any interruption that may have taken place
in the fun6lions. Each organ is eaiily thrown into
diforder, and the derangement which continues,
for v/ant of the ftrength necefTary to repair it, foon
becomes itfelf the caufe of a new afFe6lion ; and
hence we often fee a fucceffion of different de-
rangements produced by each other, all arifing
from one flight caufe, which nature had not power
to overcome, and which art is not able to prevent.

190. The violent and unufual impreffion of any
caufe whatever on organs eafily irritated, produces
numerous ^blegma/ice.

The phlegmafia of any organ always confifls In
a change in the flate of the fun6lion peculiar to it,
with an alteration*in its intimate ftrudure.

It may be readily conceived that every part of
the body is fufceptible of this mode of affection ;
that each muft exhibit it in a manner peculiar to
itfelf; and that the fame organ may prefent a great
number of varieties in this order of difeafes.

The greatefl: and mofi: important difference in
the phlegmafies arifes from their progrefs. Some

G 3 proceed

S6 REFLECTIONS ON THE

proceed in a rapid manner, foon produce a general
derangement, and either terminate at the end of a
fhort and hmited period, or are changed into
chronic afFe(5lions. Others are exceedingly flow
in their progrefs, and in the courfe of time often
produce very great alterations, without having
been obferved at their commencement. It may
be eafily conceived, that between thefe two ex-
tremes there mufl be a great many intermediate
fhades.

Phlegmafias vary in the different organs, and in
the analogous parts are the fame ; fo that the dif-
ferent anatomical fyftems of organ sfurnifh the na-
tural divilions of this clafs of difeafes.

It may, indeed, be readily conceived that a mu-
cous membrane, for example, mufl be affected in
an analogous manner, whether it ferves to form
part of the aerian, alimentary, or genito-urinary
pallages. The cafe will be the fame in regard to
the ferous membranes, the cellular tifTue, the bones,
the mufcles, the fkin, &c,
(

191. We fhall here take a curfory view of the
different kinds of phlegmafias ; beginning with
thofe which appear to be fimplefl.

When, the fkin has been divided or cut, the
edges of the wound tumefy, and become red and
painful ; the heat and circulation in the part are
increafed„ Thefe firfl phsenomena refull from the

laceration

HISTORY CF DISEASES. 87

laceration of the nerves. Soon after the e(lo;es of
the wound Jecrete a vifcous fluid, which is efFufed
between the lips of it, and caufes them to ad-
here.

When the divifion is very fmall, and does not
reach beyond the Ikin, the union nnay be effedied
in a few hours. On the other hand, when large
and deep a much longer time is required j but, in
all cafes, it is fooner eifedled according as the
union of the edges has been more exa6l, and as
the individual enjoys a better ftate of health.

The edges of the wound may unite, even though
they have fuftained a violent contufion ; though
they have remained feparate for feveral days, and
though they retain between them .coagulated blood :
fo that it is always proper to try to efFe£l an union
by the means which the art of furgery indicates in
fuch cafes, as long as the part is not afFeded by a
general phlegmafia.

Almoft all thofe topics which are employed to
favour the union of wounds are at leaft ufelefs.

When it has not been poffible to unite a folu-
tion, the edges fecrete a vifcous fluid.; cicatriza-
tion takes place flowly, and in the manner of
wounds with a lofs of fubftance. In the latter,
as in cafes of fimple diviiion, the phcenomena
arifing from la^fion of the nerves, and their expo-
fure to the air, firft take place ; the fecretion then
becomes more abundant, and the wound grado-

G 4 ally

8gf REFLECTIONS ON THE

ally cicatrizes from the circumference to thecentre,
by the formation of a new epidermis.

When nothing but the epidermis has been re-
movedj as is the cafe in flight burns, cicatrization.
is fpontaneoufly effedled in every point at the fame
time.

The method mod proper for favouring the cica-
trization of a wound is to apply nothing to it. This
iTiethod, which is certainly the lirapleft, is perhaps
Ihe only one which has never beeq thought of. I
have obtained yery rapid cicatrization by covering
ulcers with a pierced dreffing. By thefe means
they are defended from the contadl of every body,
and from the impreffion of the atmofphere^ while
the air is allowed to circulate at their furface : the
air carries off the hurnidity difengaged^ and which
by remaining oppofes cicatrization.

The ^us^ called laiidahle, which is formed In all
deep wounds^ is not produced at the fiirface of
thofe which are left expofed to the air. The for-
mation of this pus is. promoted and maintained by
the application of the foreign body which covers
it. Thofe which remain expofed to the air fufFer
to e'^ude from them a fmall quantity of vifcid. fe-
rous matter, which becomes dry, and below which
the epidermis is formed.

There are a great number of cafes in which it
is found necefTary to cover wounds. The laws of
phyliology, like thofe of philofophy, can rarely be

applied

HISTORY OF DISEASES. SQ

applied In their whole extent; but whatever method
be adopted, thefe laws mull always be employed
as a guide.

Thus, in every cafe where dreffing is requifitc,
it muft never be forgotten that the moft beneficial
Gourfe, when poflible to be followed, is to apply
nothing to the wound ; and therefore the leafl
irritating fubflances ought to be ufed, thofe befl
calculated to abforb the pus which is formed muft
be chofen, and care fhouid be taken that they do
not adhere to the edges where cicatrization is
taking place.

No topics have the property of battening, in a
dire6l manner, the cicatrization of wounds, and the
beft vulneraries are thofe which do the leafl hurt.
However, when the wounded part is in a ftate of
weaknefs which retards the procefs of cicatrization,
all flimulants may become ufeful vulneraries.

Wounds cicatrize the fpeedier the frefher they
are, and the founder the conflitution of the indivi-
dual. It will therefore be proper, in all cafes, to
endeavour to bring them back to the recent ftate,
and to refiore firength to the organization. The
appearance of a wound may always ferve to indi-
cate the ftate of the individual's health.

When an ulcer has been of long ftanding, either

in confequence of the individual's bad health, of

the peculiar weaknefs of the wounded part, or of

any local irritation whatever^, nothing is fecreted

J but

go REFLECTIONS ON THE -

but fanious and fetid pus 3 its edges become hard
and callous, the adjacent part aflumes a violet co-
lour, and at length lofes its former fcnfibility» In
this ftate of things, it will fometimes be proper to
make a new wound in the old one, in order to pro-
duce cicatrization,

192. Phlegmafia of the cellular tifiue exhibits,
in the formation of phlegmon (tumour), a feries
of phaenomena the progrefs of which may be
eafily followed.

When a thorn is introduced beneath the fkin,
the individual immediately experiences an acute
pain, which gradually ceafes ; but fome days after
there comes on around the prick a flight rednefs,
with fwelling and heat, and the pain is renewed.
Sometimes, alfo, a general derangement of a flight
and tranfient nature takes place.

If this new mode of a61ion continue, the fwell-
ing increafes and fpreads; a flight tumefadion of
the neighbouring lymphatic glands takes place :
a fmall tumour then arlfes, which becomes white,
breaks in the moil prominent part, and affords an
ilTue to the pus, which carries with it the thorn.

The prefence of the thorn was not neceflary to
give rife to all this feries of phasnomena ; the
prick alone would have been fufHcient to produce
ihem.

Hence, the prick of a needle often produces

phlegmon^

HISTORY OP DISEASES. ^1

plilegmon, efpecially in perfons highly irritable,
weak, or difeafed, and who, in this cafe, are faid
to have hadflejh.

Inoculation with the vaccine matter produces
alfo the fame feries of general phaenomena, and
the phlegmon arifing from it exhibits a conftant and
invariable progrefs j becaufe the fubftance which
occafions its development is always of the fame
nature. The cafe of the thorn, that of a fimple
pundlure, and of the vaccine inoculation, exhibit
nothing common or efTential but the prick, or the
impreffion made by conta6l on the nerves of the
wounded part.

Every prick in a nerve produces a change of
ftate, more or lefs continued, in the general adion
of the nervous fyftem : when this new mode of
action is continued on the wounded part, it gives
rife to phlegmon. This change of ftate is often
only momentary, and fo tranfient as fcarcely to be
perceptible. But in many cafes it manifefls itfelf in
an evident manner by a general indifpoiition, and
the peculiar derangement of diffei^ent functions.

In all cafes of pricking, as the prefence of the
foreign body in the part, and its tranfmiffion into
the mafs of the blood, are not necefTary to produce
the general derangement and particular formation
of the phlegmon, the hypothefis .of abforption is
entirely unfupported by proofs.

Of

gl REFLECTIONS ON THE

Of the numerous caufes of phlegmafiae, tbofe
which exercife the greateft a6lion on the nerves
are, in general, the fubftances fecreted or difen-
gaged from organized bodies in a ftate of difeafe or
of putrefacflion.

Hence, after a prick made in diilecling a dead
body in a high flate of putrefadion, that is to fay,
by the contaft of the cadaverous moleculas, at a
certain period of decompoiition, with fome of the
nerves of the hand, there may take place in the
courfe of a few days rednefs, fwelling, heat around
the wounded part, and then ihooting pains, which
gradually increafe in a continued manner, fo as at
length to become infupportable.

Thefe firft local pha^nomena are foon followed
by a general derangement of the fundions. Hence,
there come on : pain in the head, weaknefs and
confufion of the fenfes, tranfient delirium, pro-
ftration of ftrength, fhivering, acceleration of the
pulfe and of refpiration by paroxyfms; greater
heat of thefkin, fweats, lofs of appetite, new mode
ofa6iion in moft of the organs of fecretion, &c.

This feries of phsenomena, which affume the
name of fever, vary indefinitely, according to the
caufes, and to the difpolition of the individual.

After the fwelling has acquired a certain degree
of intenfity, it gradually fubfides, as well as the
febrile fymptoms : if the latter continue to in-
creafe

HISTORY OF DISEASES. Q3

creafe there is formed a co]Ie(5lion of pus, which is
fometimesre-abforbed, or which diftends the fkin,
burfts it, and is difcharged.

But when the weaknefs is exceffive no purulent
colle6lion is formed ; the progrefs of the phlegmon
is fufpended, and it may happen that the wounded
part will gradually lofe its a6lion. It then afTumes
a blueifh, livid tint, becomes indolent, and falls
into a ftate of gangrene.

In the laft place, if the flrength is re-eftabli(hed,
and if th^ febrile fymptoms ceafe, the wounded
part gradually refumes its vitality, the dead parts
detach themfelves, and there remains an ulcer
which cicatrizes ilovvly from the circumference to-
wards the centre.

Phlegmon being an afFedion peculiar to the
cellular tiffiie, it may take place in all the organs
provided with it. Its fize varies, from the puflule
fcarcely perceptible, to the tumour which contains
- fometimes more tlian a pint of pus. When the
phlegmon pafles through all its ftages it termi-
nates in an abfcefs ; but it may flop at any of its
periods : abfcefJes which already contain a large
quantity of pus. are often feen to difappear in a
fhort time. In this cafe, the purulent matter has
been decompofed or digefled, and transformed into
moleculae fufccptible of returning into the torrent
of circulation, or of being thrown out by the ufual
excretory pafiages.

The

94 REFLECTIONS ON THE

The progrefs of phlegmon is generally ftopped
when there comes on a fudden derangement in
ibme other part : the coincidence of thefe twp
phsenomena has given reafon to think that the
pus proceeds to the part newly affe^ledj to produce
there, by its prefence, the fymptoms before ob-
ferved. From this circumftance the whole theory
of metaftafis has originated.

Thus, for example, a man has on his thigh a
phlegmon which begins to enter into a ftate of fup--
puration j boiling water falls upon one of his legSj
and the tumour difappears. The latter may be
diffipated alfo, if he experiences a violent cold, or
meets with any unexpe<5ted event in which he is
deeply interefted, and which engages his attention
for fome time. In all thefe cafes, the pus of the
phlegmon has not proceeded to the legs, nor to
the breaft, nor to the intelle6lual organ : thefe
are only varied phsenomena of the nervous adlion,
which fucceed each other, and afTume each other's
place according to the ratio of their intenfity.

In all cafes of phlegmon, the produ6^ of the fe=
cretion becomes an irritant, Vvbich may at length
give rife to further ace icier ts : thus its continued
prefence around a bone p;-: - profluce caries, Sec.

From thefe obfervatior : it is clearly {een how
ridiculous it is to be cor:" nually endeavouring to
make a phlegmon fupp;jrate; which always pro-
longs tfie difeafe, and cnen produces ugly-cica-
trices, without any advantaf^e,

8 ^ Pretended

HISTORY OF DISEASES. g^

Preiended refolvents and difcutients, habitually
employed, feldom produce any adlion. A phleg-
mon may be checked in its progrefs by all thole
means which are proper for determining a flrong
and continued a6lion towards another part.

In' a word, it often happens that nature fports
with all our means, and brings to fuppuration
thofe tumours which we are defirous of fufpend-
ing, and fufpends^thofe which we wiHi to bring to
a ftate of fuppuration.

A phlegmon may take place not only in the cel-
lular tiffue furrounding the different parts, but alfo
in the parenchymatous fubftance of fome of the
organs, fuch as the lungs, the liver, the kidneys,
&c. It then exhibits numerous varieties which
depend on the ftruclure of the aiFedied organ, on
the difpolition of the individual, on the rapid or
flow progrefs of the phlegmon, &c.

A part may be afFe6lcd without any diredl im-
prcflion, and merely by means of its relation with
other organs. Hence phlegmonous tumours are
not always the refult of the acftion diredlly exer-
cifed on the nerves of the part where they take
place ; they often arife from a remote caufe : of
this kind are thofe formed around the glands at
the end of feveral acute difeafes, fach as buboes in
iyphilis, &c.

In all cafes of phlegmon the termination is the

fpeedier

gd . ' REFLECTIONS ON THE

fpeedier as the conflitution of the Individual af-
fe(5ted is (Ironp-er.

o

In the different clailes of yertebral animals, the
cicatrization of wounds, the development and pro-
grefs of phlegmonous tumours, are abfolutely the
fame as in man, and exhibit no eflential difFerence.-

193. The ferous membrane which lines the tho-
rax, the abdomen, the cranium, and the articular
capfules ; which covers the Tungs, and forms the
exterior tunic of the Homach, the inteftines, the
bladder, the matrix, &c. exhibits in its phlegmalic
afFedlion peculiar phaenomena.

This affedion, in its rapid progrefs, produces
excruciating pain, and fuddenly gives rife to a
leries of febrile phaenomena exceedingly violent
and almofl continued.

The afFe(5^ed membrane fwells ; and, inf^ead of
the fluid which habitually exudes from it, fecretes
in abundance a thick albuminous fluid, which coa-
gulates into flakes or lumps that float in the fero-
lity, or into a thick membrane, which produces ad-
hefion between the contiguous furfaces of the fe^
rous membrane.

The albuminous fluid fecreted in phlegrnafia of
the peritoneum is found in curds araidll: the ferous
fluid of the abdomen, and refembles, in fome mea-
fure, the concrete cafeous part of milk floating in

the

HISTORY OF DISEASES. gy

the ferum. After difficult births, the matrix fomeif
times experiences a fort of phlegmafia, which
fpreads along the peritonaeum, and gives rife to a
fever which often proves mortal {puerperal fever).
Several phyficians have confidered the albuminous
fubftance then found in the abdomen as effufed
milk ; but this fuppofed milk is found in men as
well as in women, after all thofe phlegmafiae of the
ferous membranes of the abdomen which have had
9. fatal termination, and particularly after the ope-
ration for a ftrangulated hernia.

It feems probable that the vulgar error of milk
difFufed throughout all the parts of the body, has
arifen from this erroneous idea, that milk is fufr
ceptible of being effufed into the abdomen. It is
aftoni{hing to find perfons of good fenfe who con-
flder rheumatic pains as the efFe6l of effufed milk,
and who ferioufly believe that there are remedies
capable of cauling the milk in its curdled ftate to
be evacuated by flool, even a great number of years
after the individual has been delivered.

Acute phlegmafise of the ferous membranes are
always dangerous, and often fatal. It is of great
importance, therefore, to difcover them at their
commencement, in order that 4he means proper
for eradicating them may be employed. The
principal means on which a dependance can be
placed are, to weaken the general a6tion of the
nervous (}ftem, when the fever exhibits no perni-

VOL. iir, H cious

gS REFLECTION'S ON f HS

clous character, like that called the puerperal j and
to excite ftrong, continued, and varied irritation
in other parts than that which is afFe61ed.

The ferous membranes may alfo be the feat of
chronic phlegmafias, which increafe very llovvly ;
which are ■ almoil always miflaken at their com-
mencement, and over which art has very little
power. ' ■ '

Domeftic animals are iubjedl to acute afFetftions
of the ferous membranes, which exhibit a feries of
iymptoms analogous to thofe obferved in man.

^-^ 194, The white fibrous tifllies which terminate
the mufcles and furround the articulations experi-
ence a fort of phlegmafia, which for the moft part
feems to be produced by the long continued a6lion
of a particular damp cold. It rarely attacks ro-
buft perlbns continually expbfed to the incle-
mency of the feafons ; but more readily the
inhabitants of large cities, of a weak conftitution,
and who are feldom expofcd to the adion of the
weather.

This, rheumatic afFe61ion announces . itfelf by
a fort of painful torpor in a certain part, which
increafes fometimes to fuch a degree as to be-
come a lacerating pain. It is often accompa-
nied by fwelling with rednefs, great fenlibility of
the Ikin, and difficulty in the mufcular adlion.
Thefe firft fymptoms are frequently attended
4 with

HISTORY OF DISEASES. g{)

With a feries of febrile phacnomenaj which are
often exceedingly violent. r..-,

One peculiar charadter of this' a'^'^^idn is, that
it iiiddeniy ihifts, or ceafesiii -one part to re-ap-
pear i'n aiiother. It thus often fiiovvs itfelf alter-
nately'in iall' the-EPPtieulatio'ns^ and even returns to-
the firft.

Rheumatifra varies, both in regard to its dura-
tion and to its intenfity, from a' limple fleeting
pain, which fcarcely lafts^afeyv^ days,- t-O a general
afFe6lion which cotifih'fes thfe itidividtt&l to bed for
iive or fix weeks.

After parturition^ women being weak and-ex-
cieedirigly ferifible to cold, frequently experience
rheumatic affe61ions, which by fome are confi-
dered as effh/hd milk i'

• Rheamatifm often takes place without febrile
iymptoms, and without fwelling of the parts. In
this cafe, it announces itfelf by pains, more or lefs
acute, which return by paroKyfms, and fometimes
become intolerable*

In fome cafes thefe pains give rife to a fwelling
of the periofteum of fome of the parts, and are then
generally confidered as lymptoms of fyphilis.

It is to be remarked,, that it is always to fyphilis,
01* to the pretended ejfufed irulk^ that all thofe dif-
eafes the character of which cannot be ealily de-
termined are afcribed ; and when cured by the
means ufed for fuch affedlions phyficians think

H 2 themfelves

lOO REPLECTIOKS ON THE

themfelves authorized to fay: ''Such a difeafc
yielded to mercurials, confequently it was vene-
real ; fuch another difappeared in confequence of
ufing thofe purgatives called antila^ics, and there-
fore it arofe from effvfed milk." Thofe who reafon
in this manner evidently fhow that they are ba4
logicians.

When rheumatifm afFe6ls the articulation of the
ribs and the intercoftal ligaments, the movements
of the thorax are impeded, and the difficulty of
refpiration frequently becomes very great ; which
often occafions error, and excites apprehejnfionQf
a difeafe of the lungs.

The fmall articulations exhibit in the gout an
affedlion analogous to rheumatifm ; but which,
however, is very different from it in the aggregate^
of its accefibry phaenomena, of its caufes, &c. It
contracts a fort of regular or irregular periodicity,
with an uniform or anomalous progrefs.

The adtion of the damp cold which excites
phlegmafife of the white fibrous membranes, often
produces thofe alfo of the mucous membranes ; fo
that thefe two orders of phlegmaliae fometimes
take place by alternatiooj and reciprocally fufpend
each other : which occalions a belief that in this
cafe alfo the humour proceeds from one part to
another. Thus it has been fuppofed that the gout
can afcend to the llomach, or proceed to the blad-

derj 8cc.

Acute

HISTORY OF DISEASES. 101

Acute rheumatirm is fometimes checked at its
commencement by means proper for diminifhing
the powers, and by exciting in the gaftric organ
a point of irritation frequently renewed.

The pains of chronic rheumatifm are diffi-
cult to be removed. They appear, however, to
have been diminifhed by an increafed a(9:ion of
the fkin, and of perfpiration, by means of dry fric-
tion, clothes of waxed tafFety, &c.

In a word, this order of difeafes exhibits alfo
feveral very ohfcure points, which are deferving of
farther obfervation.

As this order of difeafes is excited, for the moft-
part, by the unaccuftomed adion of damp cold on
feeble individuals, animals which, in general^ exhi-
bit more vitality, and which are habituated to all
the variations of the atmofphere, do not feem to
be fubjed to them.

195. As the eflential ufe of the mucous mem-
branes is to fecrete fluids proper for lubricating
the pneumo-gallric and genito-urinary paflages,
and to furnifh digeftive juices, the phlegmatic of
thefe parts muft manifeft themfelves chiefly by
a change in this mode of fecretion.

When a part of the mucous fyftem has received
the impreffion of any foreign caufe whatever, either
dire6t or indireft, a fenfation of flraitnefs, drynefs,
and ardour, is experienced in that part. The habi-
tual fecretion is fufpended, the tides of the mucous
H 3 organ

302 REFLECTIONS ON THE

organ fwell, febrile fymptoms appear, and in a few
days tbere is fecreted a large quantity of a ne\y,
limpid, and higbly irritating fluid.

As the other febrile fymptoms difappear, the pro-
du61; of this new mode of adlion becomes infenfibly
thicker, and Igfs irritating; the mucous organ
gradually rdlimes its uilial fun<51ion, and fecretion
its natural chara61er.

In this order of difeafes the new fecretion always
itrongly irritates the organs on which it is eifuled,
and produces further accidents, variable according
to the ufes of thefe organs. It is this fecretion
which ocpalions fneezing in coryza ; cough and
difficulty of breathing in colds; tenefmus in dy-
fentery ; frequent deiire of voiding urine in gonor-
rhoea, &c.

The peculiar fecretion which refults from this
new mode of adlion was long confidered by phy-
licians as the direct caufe of the difeafe, while
it evidently appears that it is only the prpduft
of it.

They were of opinion that the difeafe arofe from'
a. humour which infected the mafs of the fluids,
and that nature endeavoured in this manner to
free itfelf from it.

This hypothefis miaft have firft been formed at
a time when phyfiological knowledge was very
limited : on it was founded humoral medicine,
which was eafily applicable to all difeafes. It was
indeed fuppolcd, that as a humour evidently ap^

peared

HISTORY OF DISEASES. 103

peared .to be the caufe of difeafe in catarrhs, ; it
might exlft alfo in all other cafes, though in .a
manner lefs apparent ; and every time that a fpon-
taneous alteration took place in the ftruStiire or
fundlioti of an organ, it was faid that the morhljic
humour had proceeded thither.

This theory foon obtained credit, and at length
became popular, becaufe it was exceedingly con-
venient to account for every thing to perfons who
had no idea of the laws of organization, and be-
caufe the means of cure moft commonly employed
feemed very often to fupport it.

In the fuppofition of a humour which proceeds
to a certain part and deranges its action, it was
natural for phylicians to endeavour to divert it, by
making it ifTue through the Ikin, or by evacuating
it by ftool or by urine ; and as they were obliged, in
order to produce this effe^, to irritate very ftrongly
fome other part, they in this manner often deflroy-
ed the foreign action which conftitutcd the difeafe.
But it riiay be readily conceived that this practice,
founded on a falfe theory, muft have as often proved
fatal as beneficial.

The new mode of a6tion which is efiablifhed in
catarrh may be fufpended, in the commencement,
by all thofe means capable of exciting a powerfql
and continued atSlion in Ibme other part than the
affected membrane. For this reafon, emetics em-
ployed fo as to produce naufea, and repeated feve-

H 4 ral

104 REFLECTIONS ON THE

ral times, fucceed fo often in catarrhs of the aerlaa
paflages.

* ; This new mode of a6lion may be changed alfo
hf applying to the affeded membrane a new irri-
tant, more energetic or frequently repeated. In
perfons of a good conflitution, catarrh terminates
fpontaneouily at the end of a period which varies
from fome days to fome months, according to the
organ affedled, the nature of the irritant, and the
difpofition of the individuals, &c.

Catarrhs may be indefinitely continued by the
repeated application of the fame irritants which
produced them ; by local or individual weaknefs,
and by the force of habit.

The caufe which for the moft part produces
catarrhs of the aerian paflages (colds), is the fud-
den impreflion of damp cold air, in a ftate yet un-
known, on the nerves of thefe parts. Perlbns of a
weak conftitution, and not accuflomed to breathe
this air, receive the impreflion of it fooner than
others..

The a£Hon of this damp and cold air on the
aerian paflages is flronger, according as the tempe-
rature of the Ikin is higher ; fo that people will
more certainly be attacked, the more they endea-
vour to fecure themfelves by the common means.

To remain, therefore, in winter continually fliut

lip, to be always warmly clothed, or to go abroad

when heated, are the fure means of acquiring tlie

8 difeafe

HISTORY OF totSEASES. 105

difeafe by the firfl impreffion of cold damp air on
the lungs. On the other hand, thofe thinly clothed,
thofe habitually expofed to the air, and thofe who
avoid overheating themfelves, are fcarcely evef
fubjedl to colds.

Theadlion of the cold damp atmofphere may
jifFe(5l a ^art of the mucous fyftem, without mak-
ing a direct impreffion on it, but by exercifing an
adion on a diftant part. Hence, damp cold in
the feet produces catarrh of the aerian paflages,
and often alfo of the inteftinal furfaces.

We are taught by obfervation, that the oftener
people have been attacked by catarrh, the more
readily they are alfeded by it ; and that the lon-
ger a catarrhal difpofilion has continued, the more
difficult it is to be deftroyed.

In gonorrhoea, the produd of thfe fecretion is
contagious, iand the application of it to the genito-
urinary membrane of another individual produces
the fame affedlion : the latter, in like manner, may
be propagated indefinitely by means of contad.

It is, in all probability, the contagious charader
of this fort of catarrh that renders its progrefs fo
tedious,, and its termination often, fo difficult,
when left to itfelf, in individuals of a weak con-
ftitution.

This urethral catarrh may be cured pretty foon
by means of ftimulatifig injedions, which change

the

106 ' REFLECTIONS ON THE

the contagious mofje offecretion into anotljer not
contagious.

When catarrhs are frequently renewed, or have
continued a very long time, they often give rife to
chronic affedlions exceedingly troublelome : of
this kind are callofities in the urethra, leucorrhoea,
vefical catarrh, catarrh of the aerian paffages,
phthifis pplmonaris.

In thp Jaft mentioned cafe, when continued
emundories are eftabhfhed (cauteries, veficatories),
with the intention of producing a derivation of a
humour^ the only effe6l obtained in general is, to
have two difeafes inftead of one ; and both tend
equally to weaken, by drawing off juices rich in
nutritive parts, and more fpeedily bring on con-
fumption .

Domestic animals are pot much ful^jedl to ca-
tarrhal afFedtions, becaufe they are more habitually
cxpofed to the variations of the atmofphere ; but
thofe which, by a peculiar firu61ure of their nof-
trils, are apt to have the glanders, exhibit in that
fort of coryza a catarrh much more troublefome
than any of thofe which affedt the human fpecies.

196. The mucous membranes which line the
pneumo-gadric and genito-urinary paflages, arp
continued with the fiiin on the edges of different
natural apertures \ and it might be faid^ that in

thefe

piSTORY OF. DISEASES. }0f

thefe part? the Jatter is folded back to line thefe
different cavities. . It is obferved, alfo, that the
cutaneous and mucous fyftems have a> great rela-
tion in their reciprocal fun<51ions.

It cannot, however^ be denied, that tliefe tw^o
l}'ftems of organs exhibit very flriking differences
in their intimate flfu6iure, efpecially during va-
rious difeafes to which they are fubje6l.

Affedlions of the ildn exhibit a new mode of
a6lion and fecretion, with or without alteration ia
the intimate flru6lure of that organ.

They may arife merely from the fecretion of the
ikin being increafed or changed ; or they exhibit
themfelves under the form of eruptions, of divers
forms and fizes ; of phlegmonous pullules ; furfu-
raceous, fquamous, fcabby, or ulcerated fpots.

In fome cafes, the produdt of the morbific fecre-
tion is contagious.

In robuft individuals,, whofe Ikin is continually
expofed to the air, this organ becomes brown and
, tanned, infenlible to all imprcffions of the atmo-
fphere, and is iiibje(5l to no difeafe.

Qn the other hand, cutaneous affections are
pumerous among the civilized nations of tempe-
j-ate or warm countries, who live in a luxurious
manner, and whofe Ikin habitually Ineltered is
highly feniible to the adlion of all irritants which
come in contact with it. They are more fre-
(juent, alfo, among individuals who, being born

with

108 REFLECTIONS ON THE

with thefe difpofitions, remain in a date of po-
verty and dirtinefs. The latter are expofed to a
great number of foreign irritants, and to the re-
action on the cutaneous organ of the produds of
its fecretion. In fome cafes of denudation, or of
difeafe, this produce often exhibits an exceedingly
acrid and highly irritating chara(5ter. It is pro-
bable, that a concurrence of analogous circum-
iflanccs has given rife to the greater part of cuta-
tJeous difeafes.

It appears that the Greeks preferved themfelves
from difeafes of the fkin, which among them were
exceedingly frequent and fevere, merely by the
habitual ufe of bathing and of un<5lions.

Bathing ilrengthens the Ikin by habituating it to
the conta(5l of a fluid eight hundred times denfer
than atmofpheric air, and cleanfes it from the
produ6^s, more or lefs irritating, of its fecretion.
Ointments, like a light varnifli, preferve it from
the too immediate conta6t of a great number of
foreign and Simulating fubftances, without in any -
manner impeding its excretion.

It is well known that the Grecian baths were
eftablifhments exceedingly magnificent, and that
they conftituted the mofl remarkable of their
public monuments.

Cutaneous afFedions, in fome cafes, are the
necelTary confequisnce of an epidemic or fporadic
fever ; in others, they are the refult of a foreign

mode

HISTORY OF DISEASES. IO9

mode of adlion excited in fome of the or-
gans * : but, for the moft part, they arife from
the immediate adlion of fome irritants on the
£kin ; and in all thefe cafes they vary as the
caufes which produce them.

Moft cutaneous afFedions terminate fpontane-
oufly at the end of a certain time, and require no
treatment. Others are indefinitely continued,
during an unlimited time, either by the force of
habit, or by the repeated contadl of the contagi-
ous produ6l of fecretion. In fuch cafes, the phyfi-
cian endeavours to fubftitute in the place of thefe
obftinate afFe6lions, others which do not exhibit
that character, and which cure themfelves fponta-
neoufly, and to produce in another organ, fuch as
that of digeftion, a ftrong and frequently renewed
aftion.

The itch is an eruption without fever, the pro-
duct of which is contagious. It is readily pro-
pagated by means of contadl, efpecially among
perfons a prey to wretchednefs and dirt, among
whom it becomes, in fome meafure, endemial.
It is cured by all thofe means proper for excit-
ing in the fkin another mode of adlion, fuch as
friction, and all irritating fubftances. A recent
itch may be fpecdily removed ; but the longer it
has continued the more difficult is the cure.

* Dr. Lorry always experienced a cutaneous eruption whcii
he ate rice.

Among

llO REFLEcflONo ON Til£

Among pcrfons who have a deihcate fkin, fric-
tion for the itch foon produces another eruptioflj
which' the furgeons cOnfidcr as pforic. This new
eruption, which may be afterwards rhaintained by
dirtinefs and ufelefs friiiions, has often been cOn-
fidered as an obfl;inate itch, and as fuch has been
feveral times treated without fuccefs ; but it al-
ways yields to means proper for allaying the irri-
tation of the fliin, fuch as reft^ bathing, unQ;ions,'_
the ufe of fine linen, &c.

No eruption but that the prodiK^i: of which is
contagious ought to be confidered as the itch.'
When this difeafe has continued a long time, it
leaves in the fidn a difpofition for producing, at
certain periods, and often for feveral years, a hevr
eruption, which is not contagious, and which
ought not to be confidered as pforic. _ In the puf^
tales of the itch there is often found an animal-
culum (acarus fcab'iei)^ which has been differently
defcribed by naturalilis, and to which are afcribed
the produdlion and propagation of the difeafe ;
but this aflertion has never been properly proved.

Tinea is cured by a pitch-plafter, in the form
of a cap, which tearing up the whole fcabby
flratum forms a new wound, the cicatrizing of
which is then fpontaneoufly effedted. This dif-
eafe would, in all probability, yield to a lefs vio-
lent remedy.

HerpeS;,

HISTORY OP DISEASES. HI

Herpes, which ha^ To great a fimllarity to ti-
nea, yields ortl}'- to analogous rheans.

In a word,' the cafe 'is the fame with all old
ulcers, which are continued by the force of habit,
and whofe hard and oallous- edges' oppofe cicatrl-'
zation. When transforrried-into a recent wound
they often heal very fpeedily.

An afFe^lion of the ikin may fuddenly difap-
pear, when a ftronger derangement takes place
in another organ. In thefe cafes, the vulgar be-
lieve, that the difeafc of the Ikin has been driven
inwards, and that it has proceeded to the, part
newly affedled ; but this difappearance bught'to be
confidered merely as the confequence of the fti-ong
a6lion of an organ which fufpends a {lighter in
another part. When the eruption is recalled, an
efFe(5l analogous to that of a veficatory is ob-
tained.

Animals in the favage ftatfe do hot feem to be
fubjecSl to any difeafes of the fkin ; but among
thofe which we fubdue, and confine together in
clofe, damp, and gloomy places, -or which re-
ceive an infufficient quantity of food, or aliment
of a bad quality, cutaneous aife6lions of a very
noxious charadler foon manifeft themfelves.

197. The glands of the lymphatic fyftem, the
other glandular organs, and ' the white fibrous

tilTues,

112 REFLECTIONS ON THE

tiflues, are fufceptible of a peculiar phlegmafia,
the progrefs of which is, in general, very flow.

When a gland is irritated, either diredllj by
the contadt of a foreign body, or indiret^ly by
the adlion of another part upon it, the gland tu-
mefies, and gradually becomes indurated. At
firfl, a fmall round indolent body is felt, which
progreffively increafes ; others arife around it ; and
the tumour otlen becomes very large, hard, and
unequal ; it remains a long time moveable, and
produces no other inconvenience than that which
refults from its weight and its polition : but at
length it forms adhcfion with the neighbouring
parts.

The cellular tifTue^ which furrounds the gland,
often enters into adion, and exhibits the whole
,feries of the phaenomena of phlegmon. Some-
times, during this operation, the glandular affec-
tion ceafes. When it perfifts, it continues its pro-
grefs as if the phlegmon had not taken place.

By opening the bodies at different periods
of glandular tumours, it has been found that
they have acquired the confiftence of concrete al-
bumen j of lard more or lefs hardened j or of a
cartilage, in the midft of which a few offified
points are fometimes obferved.

Scrophula is an atfe61ion of this kind, which
{eems to arife from a certain ftate of weaknefs, a

peculiar

aiStORTf OF DISEASES. 113

peculiar conflitution, for the moft part heredi-*
tary : its lymptoms feem to fhow themfelves more
readily on thofe organs lead fufceptible of re-
adtion, and which may be faid to be endowed
with lefs vitality.

A fcrophuIoLis conflitution is announced by a
delicate white fkin, flabby fulinefs of the fiefhs
blue and often watery eyes, bufliy chefnut-co*
loured hair^ the alae of the lips and nofe thicks
the lower jaw broad, a particular acutenefs and
delicacy of the fenfes, and often a premature in-
telligence.

This conflitution appears chiefly in large ilU
built cities, damp, and looking towards the
north. Among children it feetns to be the refult
©f an excefs of nourifhment with want of exercife.

When this peculiar -difpofition exifi:s, a point
of irritation is foon obferved to be developed in
Ibme of the glands ; thofe, for the moft part, of
the neck and . mefentery in children; thofe of
the lungs in adults, and fometimes in feveral of
the articulations. In all thefe cafes, the irritation
determines the ferics of phsenomena peculiar to
the glands, and to the white organs.

A fcrophulous conflitution, when it begins to
manifefi itfelf, may. be eafily changed by the ufeof
different ftimulants, wholefome nourifliment, ex-
crcife, and good air ; bitters, tonics, Sec. frequently
rvaried.

VOL. Ill, i Scrophalous

114 REFLECTIONS ON TKfc

Scropbalous fymptoms often difappear in con-
fequence of fome acnte difeafe^ fmall-pox, he.
They frequently difappear at the age of puberty,
when the vital force aifumes a new a6lion and a
greater degree of energy : if they perlill after this
period, they generally continue for life.

Rachitifm is a peculiar flate of the conftitution,
which feems to have the greateft analogy and often
to be confounded with fcrophula. It, however,
differs from it in this refpedl, that it affeds in a
more eflential manner the f)'ftem of the bones.
In this difcafe the bones become foft and fwelled,
and the motion and weight of the body bend them,
and often produce the mofi: frightful deformity.

This difeafe yields fometimes to the ufe of the
general means indicated for fcrophula. The
fle6lion of the bones even may be corredled, when
not very great, by the continuance of any adlion
that tends to ftraighten them,

198. Syphilis in its hiftory flill prefents a great
number of obfcurities. To have a clear idea of
them, it will firft be proper to take into confidera-
tion the primitive chancre. We fhall, therefore,
fuppofe that an ulcer in the genitals may have af-
fumed, by a concurrence of very extraordinary cir-
cumftances, fuch a character, that the product of
its fecretion, depofited afterwards on a part defti-
lute of epidermis, in another individual, gives rife

• to

HISTORY OF DISEASES. H^

to the formation of a limilar ulcer, and that this
kind of'ulcer may then be propagated indefinitely
by the means of contact.

An ulcer, in confequence of its being conta-
gious, muft be perpetuated in the individual in
whom it exifts, producing that ravage which is pe-
culiar to it, and mull occaiion, in the whole of the
nervous f)'ftem, a particular change of its ftate.

In lyphilisthis change is fuch, that it gives rife to
fubfequent accidents, which appear more readily in
fome of the mucous membranes, in the lympha-
tic fyllem, and in that of the bones.

In fyphilis, therefore, we ought to confider:

ift. The primitive chancre, whatever be its
form, which varies according to the place where it
exifls.

2d. The peculiar a6lion of the nervous lyftem
which it maintains.

3d. The confecutive fymptoms produced by
this adtion.

The primitive chancre may be eafily cured at its
commencement, by all thofe means which are ca-
pable of changing the nature of an ulcer. Thus,
profound cauterization of a recent chancre is fuffi-
cient to deftroy it. When of long (landing, mer-
curials, violent fudorifics, draffic purgatives, the
ufe of fome mineral acids, of fome alkalies, and in
general of all thofe means capable of producing

1 % and

llQ Reflections on the

and maintaining a great change in the fyllem,
caufe a termination of this morbific affection.

But fyphih's which has not been checked in its
progrefs often produces fiibfequent accidents ex-
ceedingly troublefome ; fucb as confecutive chan-
cres in different diftant parts, buboes, perioftofis,
exoftofiSj debility, with pains in the limbs, caries,
general atrophia, and a fort of confumption which
may become fatal.

It is probable that the product of the primitive
chancre canalone propagate the contagion. In
the different ftates of lyphilis all the means capa-
ble of exciting in the fyikem a f^rong and con-
tinued adion, during a period proportioned to the
time the difeafe has exifted, always cure the pri-
mitive chancre, and deflroy the fpecific a6lion
which maintained it ; but the fubfequent acci-
dents can be cured only by purfuing a courfe pe-
culiar to them, and as if they had been produced
by fome other caufe, Thefe accidents often per-
liff, becaufe improper regimen and remedies main-
tain the patient in a flate of debility which does
not allov? the organization to make the effort ne-
ceffary for effecting a cure ; and they frequently
ceafe when all treatment is abandoned, and when
a regimen proper for reftoring the ftrength is ob-
ferved.

This fimple explanation of the common pro-

greig

HISTORY OF DISEASES. H/

grefs of ij'philis is fufiicient to account for ali the
forms it affiimes, for the nature of the accidents it
produces, and for the caufe of the fuccefs or failure
of all the means employed to counteradl it.

A great number of chronic afFe^lions, which
, take place at a longer or fhorter period after the
appearance of fyphilis, are frequently confidered as
maintained by this difeafe, and confequenlly are
treated with mercurials. For the moft part they
do not yield to this improper treatment ; but even
when a cure is effedied it is ridiculous to conclude
that the malady was of a ()'philitic nature. Mer-
curials produce their efFe6l on the organization by
exciting an energetic mode of aftion, which may
be ufeful in a great many difeafes.

199, Syphilitic blennorrhagia (gonorrhoea) feems
to have the fame origin as fyphilis : it however
exhibits acharader fo diftindt that it may be con-
iidered as an afFeftion of a peculiar kind. It con-
fiflsof a catarrh of the urethral membrane, or of
the vulvo-uterine conduit. The product of this
catarrh is contagious, and when applied to the ge-
nital parts of another individual produces the fame
affedion.

This blennorrhagia, after continuing about a
month or two, fpontaneoufly ceafes; or, if it con-
tinues longer, the fecretion gradually lofes its con-
I 3 . tagious

Ijg REE'LECTIONS ON THE

fagious property, and the difeafe is changed into a
fimple chronic catarrh.

In feme women, however, blennorrhagiae of a
long Handing become, under certain circumftances,
contagions in the a6l of coition.

Syphilitic blennorrhagia, in general, ceafesfpon-
taneoufly at the end of a limited period ; but it
may be cured much more fpeedily by ftimulating
injeftions, which change the contagious nature of
the fecretion.

Syphilitic blennorrhagia, like all catarrhs, pro-
duces a general derangement, which, after the
commencement, is often exceedingly violent. It
fometimes gives rife to derangements, which take
place chiefly in parts having a very intimate rela-
tion with the organ afFecled, fuch as the glands of
the groin and the tefticles.

When gonorrhoea is fucceeded by a fwelling
of the tefticles, this new afFedlion is fometimes fo
flrong that the running is immediately fufpended.
In this cafe it may be proper to renew the fecre-
tion of the urethra, which is always free from
danger, in order to remove the difeafe of the tefti-
cle, which, is much more fevere • but it is entirely
ufelefs to endeavour to revive for this purpofe a
fyphilitic blennorrhagia: the fame refult may be
obtained from a fimple catarrh excited by any
irritating injection.

HISTORY OP DISEASES. 1 1 Q

It is highly probable, that the fecretion of a
chancre applied to the membrane of the urethra,
or of the vulvo-uterine conduit, may fometimes
produce a fyphilitic blennorrhagia ; but it is not
probable that the produ6l of a gonorrhcea can occa-
lion a chaacre.

200. The tiflue of the lymphatic glands, and that
of the glands appropriated for fpecial fecretioiis ;
the tiffue of the white fibrous organs ; that of the
bones, and even the fkin, in confequence of any
irritation, are fufceptible of experiencing a fort
of phlegmafia, the progrefs of which is generally
very flow, and the refult always uniform.

This chronic afFcftion of the glandular or white
fibrous tifilies manifefis itfelf, for the moft part,
after an acute phlegmafia of the other cellular, mu-
cous or ferous tiffiies by which they are furrounded.
Sometimes it is produced dire<5lly by any irritation
whatever. In all thefe cafes, there firfi: appears a
hard, indolent tumour, which increafes very fiowly,
and at the commencement produces no other in-
convenience than that which naturally refults from
its pofition and its fize, and from the derangement
in the fundtion peculiar to the part afFeded.

Thefe tumours, when examined at diff^erent
periods of their formation, exhibit a homogeneous
fubftance, the confidence of which has a refem-
blance to that of concrete albumen, indurated

I 4 lard^

120 REFLECTIONS ON THE

lard, or a cartilage more or lefs compact, in the
midft of which there are fometimes developed a
few offified points*, or in which are found fome
cretaceous matters ; and on this account thefe
tumours have been dillinguifhed by the name of
fcirrhiis. Of this kind are thofe tumours formed
in the glands of the breafl, after external laefion ;
thofe which take place in the lymphatic glands
of various parts, in the cafe offcrophula; thofe
fmall tumours which are obferved in different
points of the fubftance of the lungs, in phthificky
perfons ; the fwellings which arife in the oefopha-
gian and pyloric orifices of the llomach ; in the
uterus, the ovaria, the proftate gland, at the
neck of the bladder, in the reftum ; the tume-
fa£tions of the white tifTues which furround the
articulations; the different exof^ofes with a foft-
ening of the bones ; the tumours in the cellular
tifTue, after phlegmons which are faid to termi-
iiate by induration ; and, in the lall? place, thofe
tuberculous pullules which arife on the fkin, and
chiefly on the lips, the als of the nofe, &c.

All thefe affedlions, which appear to be fo differ-
ent, and which feem to have no relation with each
other, are however of the fame order ; they fol-
low the fame progrefs, and exhibit the fame mode

* An analogous ftate, but without increafe of fize, takes
place in almoft all the fpft parts expofed to long-continued
conipreirion or fr'iftion. Old age alfo frequently brings on 3
fiRiilaj: ftate in the tiffue of the arteries, tendons, 3fc.

of

HISTORY OP DISEASES. 1^1

of termination. Notwithftanding the varied f)'m-
ptoms which neceflarily refult from the peculiar
ilru6ture and numeroas ufes of the injured parts,
the fcirrhous afFedion feems to bring them all
back, to the fame ftate, by giving them the con-
fiftence of concrete albumen.

Thefe different tumours, when they attain to
the fcirrhous ftate, may remain feveral years with-
out making any progrefs, without increafi ng in
fize, and even without producing much inconve'
nience.

Sometimes, after remaining for a very long pe-
riod in a. Itate of repofc, they may again ac-
quire a progreffive ftate, if excited by any new
caufe.

Thefe tumours fometimes difappear when re-
cent and not voluminous, in individuals of a
ftrong conflitution ; but when they have once at-
tained to a certain fize, when of lon^ Handing,
and if the perfons be debilitated, they are no
longer fufceptible of a fpontaneous cure.

In this cafe, the other parts of the famp
fyftem of organs, or of an analogous fyflem, con^
traft a great difpofition to a fimilar mode of af-
fedlion, which eftablifhes a peculiar conflitution
or diathelis. Thus the fcirrhus of the glands of
one of the breafis, when of long flan ding, is
generally accompanied with that of the neigh-
feouring lymphatic glands, and with fcirrhus of

the

122 REFLECTIONS ON THE

the oppofite breafl ; and when the tumour has
made a conliderable progrefs, the whole glandular
fyftem is in general affected.

The medical art can furnifh no other means of
checking the progrefs of this evil, but extirpa-
tion of the tumour when practicable, and the dif-
ferent perturbing modes of excitement, capable
of changing the fcirrhous conditution, when not
too inveterate^ and when its effeds have not been
far extended.

The pretended diffolvents are fcarcely ever of
any life ; and cauftics, fur the mo ft part, are
hurtful.

When the fcirrhous tumour has attained to a
certain degree of in creafe, it frequently happens
that a nev\f mode of a61ion is excited, in confe-
quence of a blow, the application of a caufticj of
a phlegmon which takes place in the neighbour-
ing parts of the tumour, and of any other irri-
tating caufe. This hard homogeneous and indo-
lent mafs, which feemed to have loft its whole
organic ftructure, acquires then great fenftbility,
and experiences a feries of very remarkable phae-
nomena. There firft comes on a flight titilla-
tion, with a troublefome itching, followed by
more acute pains, which return by paroxyfms ;
in a little time the heat of the part increafes ; the
tumour becomes more voluminous and unequal ;
the fkin alTumes a reddiih brown tint, and at

length

HISTORY OP DISEASES. 123

length there is formed an accumulation of pus,
fometimes thick, but for the mofl part of a recl-
difli fluid, which is difcharged by the burfling of
the fkin. Soon after the fecretion, when it comes
into conta6l with the atmofpheric air, changes its
nature, and there are then evidently obferved all
the phaenomena of real putrefii6lion, which the
vveaknefs of the part does not permit to be fuf-
pended, but which is modified by a remainder of
vitality.

The j)ains, however, increafe with the fize of
the tumour ;. the ulcer is enlarged, exhibits an
unequal furface of a livid brown colour, and its
edges become hard, proje61ing, and inverted, &c.
The fkin which circumfcribes the tumour is of a
violet colour, and covered with varicofe veins.

In the courfe of the difeafe, the cancer flowly
deflroys all the parts which it afFedis, and even
the bones ; the deftru6lion of the venous tiflue
produces frequent haemorrhagies. When the can-
cer fpreads to the neighbouring parts, the one pri-
mitively afFed:ed exhibits fometimes an ugly fear,
rough and deprefled.

It may be readily conceived that an affection fb
terrible, accompanied, for the mofi: part, with
excruciating pains, cannot long continue without
producing diforder in all the other fundions ;
they indeed all become deranged in fucceflion,

and

124 REFLECTIONS ON THE

and the patient, at lengtb, falls into a llatc of
confumption, which terminates in death.

The animals, which we render fubfervient to
our wants, are not exempted from afFe6lions of
this kind ; but they are more rarely attacked by
them, as they are better calculated to refift thofe
caufes by which they are produced.

20I. The bones arc fufceptible of phlfgmafls,
as well as the foft parts ; but in the bones their
progrefs is much flower.

In fra6lures, as well as in wounds, the broken
extremities grow foft, fwell, become painful, and fe-
crete at firfl a bloody and ferous matter, and then
a thick gelatinous fluid, which forms an incrufla-
tion on the fradlured ends. This fluid, in ex-
uding from the two feparated furfaces, is con-
founded with them, and forms a cartilaginous
fubflance which produces a ring, always apparent
in the place of the fra6lure, and which Alls up
the cavity of the long bones. This cartilagi-
nous fubflance then pafles to the ofleous ftate,
according to the habitual mode of the develop-
ment of the bones ; and thus produces a confo-
lidation of the fracture.

Fractures, as well as wounds, are confolidated
more fpeedily, according as the feparated furfaces
are more carefully preferved in a fl:ate of reft in

their

HISTORY OF DISEASES. 125

their rerpe(?live fituatlons, and as the individuals
enjoy a better ftate of hcalrh.

The time neceflary for the formation of the
callus varies from a fortnight to feveral months,
according to the nature of the fradlure, the age
and difpofition of the individual, &c.; but the
mean term is from thirty to forty days. In fome
difeafed or highly debilitated perfons, the confo-
lidation of fradurcs may not take place; it may
alfo be prevented or retarded when any powerful
aSion, maintained on the organ, fufpends the
procefs of offiScation,

When the fradured parts have remained fepa-
rated for a long time, they both become in-
cruiled with a cartilaginous fubftance, which
acquires an ofleous nature ; and Ihe two ends, re-
tained by an intermediate ligamentous fubftance,
form a fort of articulation. In this ftate the
fra6iure cannot he confolidated but by excifion
of the ends of the bone.

When a bone has received a violent contufion,
or when it remains fome time expofed to the air,
it becomes dead in a greater or lefs extent of its
furface and depth ; a vafcular apparatus under the
form of granulated and carneous puftules is deve-
loped at the furface of the found bone ; the dead
part gradually detaches itfelf, and at length is
completely feparated at the end of a certain time,

,the

126 REFLECTIONS ON TKE

the duration of which in general is In propof-
tion to the thicknefs of the part which has ex-
foliated.

Thofe fubftances, to Vv'hich the property of
haftening the exfoliation of a bone has been
afcribed, are fcarcely of any utility.

When the bone of a limb is mortified through-
out its whole extent, the circulation between the
perioflenm and the medullary reticulation is in-
terrupted ; the bone, become a foreign body,
produces feveral phlegmons in the neighbouring
cellular tiffue : thefe tumours fuppurate, and
remain fiftulous. The phofphaie of lime, which
can no longer diftribute itfelf in a uniform man-
ner at the furface of this bone, difFufes itfelf irre-
gularly around it ; gradually afFumes its place, and
produces a new fhapelefs bone, in the middle of
which the old one is inclofed. This dead bone
occafions by its prefence, in the middle of the
new ofleous produdlion, pains which are often
excruciating, and which render the extra6lion of
it neceflary when poffible. During the whole
courfe of the difeafe, the mortified part produces
and always maintains fiftulous ulcers, even through
the new bone, which is thus perforated with feveral
holes.

This mortification may be produced artificially
in an animal, by making an aperture in a long

bone^

HISTOHY OF DISEASES. 107

bone, in confequencc of which the liru^iure of
the medullary reticulation may be altered. (See
Les Experiences de Troja.)

When the mode of a61ion of the vafcular tilTue
of a bone has been changed by any caufe what-
ever, this organ may become altered and fwelled 5
in which cafe the fecretion of the phofphate of
lime is increafed or diminifned.

Thus the violent contufion of a bone; the pre-
fence of fome phlegmons or chronic ulcers in the
neighbourhood ; the general a<5lion maintained
by lyphilitic, fcrophulous, fcorbutic, and cancerous
afFedions, and all difeafes which, by their long
duration, have greatly exhaufted the vital forces,
may produce a change in the natural a6lion of
the vafcular tifTue of one or more bones.

Sometimes the fecretion of the phofphate of
lime is diminiflied ; the bone bends, and is eafily
broken : at other times its vafcular tifTue is gra-
dually weakened or deftroyed ; in which cafe
the folid part of the bone becomes brittle and
friable.

In fome cafes, the bone fwells, and the fecre-
tion of the phofphate of lime increafes to fuch a
degree, that the accumulation of it may give to
the bone the confidence of ivory.

This eburneous exoftolis may produce no other
inconvenience than that which refults from its
iize and pofition.

In

228 REFLECTIONS ON THE

In other circumftanceSj the vafcular part fwellsj
and is fometimes conliderably puffed up ; the fe-
cretion of the calcareous fait decreafes, and the
bone gradually lofes its confiftence, and affumes
that of cartilage. At other times, ^e vafcular
tiflue, by increafing in volume, feparates and dif-
tends'the laminae of the bones ; and the refult is
a large carniform mafs, which fupports in part
a light cavernous Skeleton formed by the oiTe-
ous fragments and afperities.

Sometimes the fwelling of the bone takes place
very fpeedily, with rednefs, heat, acute pains in
the part, and febrile fymptoms. At other times
it is produced flowly and with very little inconve-
nience. The difeafe may fufpend its progrefs
even for a very long time, fuch as feveral years,
and afterwards refume it.

When the ofleous tiifue has attained to a cer-
tain ftate of weaknefs, with a peculiar mode of ac-
tion, whether the bone be in the neighbourhood
of chronic phlegmons or ulcers, or only in contact
with the atmofpheric air ; or, whether it has in-
creafed in (izie, efpecially by afluming a cartila-
ginous confidence, this ofleous tiffue may acquire
an a6lion analogous to that acquired by the foft
parts, during the phaenomena of gangrene or ul-
cerated cancer ; and may produce ichorous or
fanious pus, which will effe6l a folution or de-
compofition of tke ofleous organ.

^ • Carhi

HISTORY OJ" DISEASES. 3 2g

Caries makes a more rapid progrefs when it
affects the fpongy bones, and when it takes
place in contadl with the atmofpheric air. It is
the more difficult to be checked as the indivi-
dtJlal is more debilitated.

The progrefs of caries may fometimes be
checked by complete excifion of the difeafed part,
or by cauterization ; and by all thofe means ca-
pable of reftoring ftrength and energy.

In all difeafes of the bones it mud always be
remembered, that it is the vafcular tifTue alone
which exhibits the phenomena oi difeafe, fince it
alone is the living organ, and becaufe the alter-
ations which take place in the fecretion of the
phofphate of lime are merely the refult of the
mode of afFedion of that tilTue of vellels.

Draught animals, whofe mufcular exertion we
continually employ, are expofed to violent efforts
which may often give rife to difeafes in their
oflfeous parts ; and we indeed find among them all
thofe modes of alteration of which that fyftem
of organs is fufceptible.

202. From this curfory view of the numerous
phlegmafiaD to which the different parts of the
organization are fubjedl, feveral important truths
may be deduced.

They are all produced by an impreffion made
diredly or indiredlly on the organ afFe<Sed, by an

'VOL. m. K irritating

laO kEFLEdTio^^s OJr the:

irritating: caufe, which altering, more or lefs^ itg
organic ftru61ure, gives rife to a change in its
mode of adtion.

Robuft men and animals refift the greater part
of the caufes of phlegmafise ; and thofe which in
fuch men and animals refult from violent external
Isfion are aKvays Ipeedily cnred.

An organ yields more eafily to the I'mpref-
lion of pblegmalic caufes, according as it is
weaker, and as it has oftencr experienced their
aciion.

Phlegmatic affections are the more troubleforae,
and the more difficult to be healed, the older they
are, and the weaker the conftitution of the indi-
viduals attacked by them.

All thefe afFe61ionSi in the fucceffion of their
phaenomena, exhibit a flower or more rapid pro-
grefs. Almoil all the anatomical. fyftems of or-
gans are fufceptible of thefe two modes of a6tion^
which reftore health, or bring on death by a feries
of condant phcsnomena.

The organs affedled by phlegmada experience
derangements, Vv'hich are particularly remarkable
in the exercife of the funclions peculiar to them.
Thus the iecretory organs experience changes in
the mode of their fecretion. The new produdf:,
which is evidently the rcfult of the difeafe, has
bcea conlidered as the caufe of it, and has given
rife to the theory q{ hmnours.

In

HiSTOHy OF DISEASES, 131

th fome cafes, the produ6l of the morbific f6-
cretion, applied to a fimilar organic part of. an-
other individual, produces the fame afFeciionj which
is thus propagated by the way of contadl.

The greater part of the phlegmafise may be
checked at their cOmfflcncement, and often fuf-
pended in their pfogrefs : Ibme teduce the art to
mere expe^latiOn.

A violent phlegitiaiic afFctftion feiTiOves, in ge-
neral, one that is lefs fo.

The alternation which often fpon t an eoufly takes
place between phlegmaliEE of different degrees of
ftrength in different organs, has induced fome to
believe in a tranfpoi'tation of hurnours, and given
rife to the theory of metajiajis.

The principal means, employed with advantage
in thefe difcafes, tend either to excite irritation in
a part different, from that which is afFe6ied, or to
change the mode of action which conftitutes the
difeafe, or to remove the produces of the fecretion,
the prefence of which may maintain the derange-
ment and produce further accidents.

In acute phlegmafia it is, for the moft part, pro-
per to diminifh the general or local powers, while
it is almoft always neceHary to maintain or to in-
creafe them in thofe which are chronic.

Acute phlegmafiss foon difappear, produce deaths
or are converted into chronic. The latter almoft

K a always

132 REFLECTIONS ON THE

always lead flowly to a ftate of confumption, which
at length proves fatal.

Acute phlegmafiae difappear by a feriesof phse-
nomena, which fucceed each other regularly in the
fame order. Art, in general, ought to refpedl this
progrefs ; and its only obje<5l fhould be to remove
every thing that might derange it. In many cafes,
however, and particularly in men of a robuft con-
ftitution, thefe difeafes may be checked at their
commencement, or even fufpended in their pro-
grefs, without any danger.

Art, therefore, may check fome of the phleg-
mafiae, and favour the progrefs of the greater part
of them ; but it cannot cure any of them.

Acute phlegmafice bring on death, in confe-
quence of the derangement which the local affec-
tion produces in all the functions, and the patient
dies by the confecutive efFe6l of the febrile fym-
ptoms. An acute phlegmafia produces, with more
efficacy, a general derangement of the fun6lions
or fever, according as the conftitution of the pa-
tient is weaker, or more irritable.

In the acute afFc^lion, the part may be fo far
debilitated and enervated as to prefent only a weak
refiflance to the laws of chemical affinity: it then
exhibits, in the rapid phaenomena of gangrene, a
real putrefadlion modified by a remainder of vi-
tality.

The

/ HISTORY OP DISEASES. 133

The chronic afFe(9:ion may maintain in the mu-
cous membranes, or in the cellular tifTue, a more
abundant morbific fecretion, which continually
weakens the individual. Befides, the injured part
deranges the funAions of the fyftesn to which it
belongs ; the diforder fpreads from one funtlion
to another, and the patient is carried gradually
to a ftate of confumption, which terminates in
death. In other fyftems of organs, and particu-
larly the glands, the white fibrous tifTues, thefkin,
and even the bones, it happens, in confequence of
a flow and gradual alteration, that the part fwells,
becomes indurated, and aflumes the confiflence of
concrete albumen or of cartilage.

Chronic phlegmafia often remains in this flate
without producing much inconvenience; but if it
again enters into a61ion, it exhibits a termination
analogous to that of acute phlegmafia : the debili-
tated part prefents only a weak refi fiance to the
chemical action ; and, in the flate of cancer and
caries, experiences all the phsenomena of a very
flow putrefaction,

203. It has been feen that acute phlegmafise
often produce by their acutenefs a general derange-
ment in the order of the fundions. But there are
fome other phlegmafiae which, inflead of being the
caufe of this derangement, feem to be the efFcd

K 3 of

134 REFLECTIONS ON THST

of it : of this kind are eryfipelas, fcarlatina, rube*
ola, and vanoiae.

In thefe diJeafes fyniptoins are developed which
announce thp general derangement of the nervous
adion ; fuch as pain in the heid, debility of the
fenfes, proftration ortlrength, lofs of appetite^ ac-
celerated circulation, derangement in the fecre-
tions^ at length fever \ and towards the fourth
day there comes on a ci^taneoias phlcgmafiaj ge-
Dpral or partial.

In variolous fever, th^ iluid contained in the
mature puftule^, either frefh or dried, becomes a
liimulant proper for producing the fame fever in
another individual, when applied, though in the
fmallcft quantity imagipable, to a part defiitut^ of
epidermis,

As this pus, for tlie mofl: part, is fecreted in
abundance from the whole furface of the body of
each patient • as it is of fuch a nature that it may
be kept a long time in a llate of deficcation, on the
fpales of the puftules, without loiing its fpeqific vir-
tue; and as it may be reduced to very fine powder,
fo as to be tranfported to a difiance by the winds,
and introduced into the aerian paflages; it may be
readily conceived that this difeafe, when once dc*
¥eloped by accidental circumftanccs, mufl be after^
wards propagated without interruption.

It is therefore the action produced by tl^e pon«

taa

HISTORY OF DISEASES. 135

tacl of this fubftance on the nerves of the touched
part, which occalions in the whole fyflem that fe-
ries of general phasnomcna which conftltuie va-
riolas, and not the abforption of it, and its being
conveyed into the general mafs of the blood, as is
commonly fuppofed,

The moil fingular phaenomenon obferved in this
difeafe is, that, when the individual has once exhi-
bited the feries of phsenomena which it produces,
the organization lofes its fitncfs for being again af-
fedeU by the variolous flimulant. We are entirely
ignorant in regard to this peculiarity, and to the
nature of the change which has been effected in
the fyftem,

But, fince the organization is fufceptible of
lofing its difpofition for being afFefted by the virus
of variolas^ it may be readily conceived that other
qaufes than the difeafe may produce the fame ef-
feft; and this caufe has fortunately been difco-
vered in the virus of the vaccina.

Thefe plain obfervations are fufficient to fhow
the folly and abfurdity of the objeftions which have
been made againfl employing the vaccine inocula-
tion as a prefervative from the fmall-pox. The
fear of a poifon introduced into the blood, capable
of producing future derangements, can be enter^^-
tained only by perfons entirely unacquainted witl:|
fne laws of the organization.

yhe fmall-pox, communicated to nuiTtcrous
K 4 tribes

-1*fi-vv

136 REFLECTIONS ON THE

tribes of people, has often occafioned the moft
dreadful ravage, by fweeping off a part of the in-
habitants, or by rendering them maimed and de-
formed.

The caufes which have chiefly contributed to
increafe its ravage are thofe proper for favouring
the eruption : thefe depend on local circumflances,
poverty, ignorance, and prejudice.

As the fmall-pox confifts eflentially in that fever
by which it is charafterized, it is highly defirable
that the eruption, vi/hich is merely a confecutive
accident, thould be as little confluent as poffible.
Some phyficians are even of opinion that an indi-
vidual may have the variolous fever vi^ithout erup«
lion, and be no lefs fecure from a relapfe : it is
poffible that fome of thofe who believe that they
never experienced this difeafe, may have had the
fever without any eruption. But the vulgar ima-
gine there can be no fmall-^pox without pullules :
they believe that every thing which comes out
was formed in the body, and that the more con-
fluent the eruption, the more certain the cure.
This popular error, which on the whole is very
pardonaUe, has been the caufe of the great ra-
vage of the fmall-pox ; becaufe all the means of
cure have been applied in fuch a manner as to
favour the quantity of the eruption, while the
9bje&. iliould have been to diminifh it.

g A more

HISTORY OF DISEASES. I37

A more rational mode of treatment, among
enlightened nations, has very much leflened the
ravages of this difeafe ; the pradice of inocula-
tion has alfo contributed to render it milder ; and
it is poffible that the vaccine inoculation may
extirpate it entirely ^ but it never will produce
this efFedl unlefs the practice be enforced by a
law, fo as to oblige parents to have their children
inoculated within a certain period after they are
born. Such a regulation, which would tend to
prevent the twentieth part of mankind from being
fwept off at an early period of life, or from being
maimed and deformed, would be of the utmoft
importance to fociety.

204. In phlegmafiss, and particularly thole,
which are acute, the local alteration often prOr
duces the general derangement of the fun61ions
which conftitutes fever, and the caufe of this
afFedlion is then evident. But it frequently
happens that the impreliion, made on an organ
by any caufe whatever, produces the general
derangement of the fun6tions or fever, without
leaving any traces of local alteration ; which has
rendered the etiology of this difeafe very obfcure.

Fever confifts in a derangement, more or lefs
complete, of the different fun61:ions, with a feries
of phsenomena which tend to bring back to
health. This a|Fe6liorj may be produced by a

great

138 REFLECTIONS ON THE

great variety of caufcs ; thus, the too long contU
nued imprefTion of heat, of dry or damp cold ;
iTfarfliy exhalations, and all thofe which proceed
from vegetable and animal fubftances iii a ftatc of
putrefadlion ; violent and forced cxercife, a tranf-
port of paffion ; derangement in the gaftric organ
by excefs or privation of food^ &c. may occafion
fever.

In this difeafe, each fanclion is deranged in a
manner peculiar to itfelf, as may be proved by a
careful examination. We indeed obferve : con-
fufion^ exalted fenfibility or vt'eaknefs of the
fcnfes ; pain in the head ; proflration of the muf-
cular ftrength, or fubfultus tendinum ; irregu-
larity in the movements of refpiration and circu-
lation i fhivering or great heat ; derangement of
the fyfiiem of digeftion : hence lofs of appetite,
thirfi^ mouth dry or clammy, &c. a new mode
©f a(5lion in all the fecretory organs, but mofl ftn-
fible in the fecretion of tvveat, urine, hc^

Though fever always confiils in a derangement
of the different fun(51ions, accompanied with a
feries of phasnomena which tend to bring every
thing back to the natural order, it is evident that
this derangement may vary in an indefinite man-
ner, according to the caufes by which it is pro-
duced, the conftitution or difpofition of the indi-
vidual, and to the combinations pollible in the
numerous tymptoms which conftitute the difeafe;

t HISTORY OF DISEASES. 13Q

.aiid hence have arifen the thoufand and one vari-
eties of fever defcribed hy nof ilogifts-

The moil ftriking difference e hibited by fever
arifes from its progrefs, which may be either con<-
tinued with remijfnns^ more or lefs fenfible ; or
xeturn by paroxyfms with covn^Aeie intermijfwns :
\yhich eftab'ifhes the natural divifion of this affec-*'
tion into remittent and mter^uittmt.

Remittent fever may be diflinguifhed alfb, ac-
cording to thfr feverity of its i}mptoms, into_/»j-
'ble remittent, which is never mortal of iifelf,
taind jpern cious rem:te?it^ which Irequenily becomes
fatal,

205. Simple remittent exhibits an indefinite
feries of tranfient fhades of little importance,
and difficult to be defined. Among thefe fhades,
however, it is poffible to eftablifh three difiindl
forms, with which the different particular cafes
are conneded in a more or lefs direcl manner.

ift. In a young man of a fangaine and robuft
conftitution, the fadden imprefl[ion of dry cold,
violent and forced exercife, a firong tranfport of
pafiion, ike. may produce a {Q,\'Qr, which is lud-
denly announced by a flight fhivering, and in-
creafes in a continued manner, with rednefs of the
face and eyes ; beating of the carotid arteries ;
llight pain in the head ; moift univerfal heat $

ample

140 REFLECTIONS ON THE

ample and frequent pulfe, &c, Thefe fymptoras
gradualij increafe, and terminate at the end of
the firft, fourth, ninth, or fourteenth day. Sy-
nocha.

ad. In adults of a llrong arid conftitution, a
firm and irafcible charafter, with a predominance
of bile, the fame caufes as in the preceding cafe,
a derangiement of the gailric ij'fiem, or ftrong
marfhy exhalations, may produce a fever, which
after fome days' indifpoiition maiaifeils itfelf by a
fudden attack ; violent pain in the head ; rednefs
in the face, with a greenifh yellow tint around the
noie and lips ; great fenlibility in the epigaftrium,
auiea, vomiting; pulfe frequent and full; dry
beat ; exceiTive thirll, &c. This fever terminates
ipontaneoufly towards the end of the fecood qr
third week. Bilious fever.

3d. Men of a weak conftitution, but for the
moll part females, and all perfons of a pale com-
plexion, relaxed fibres, and a flow character, are
differently afFedled. The fame caufes, as in the
preceding cafe, produce in them a fever, which
announces itfelf by a long feries of phenomena,
and which commences its attack in a lefs fenlible
manner. The lymptoms are : palenefs of the face^
flight pain in the head; fenfibility of the whole
abdomen ; dry cough ; mucous excretions ; pulfe
little accelerated ; nights more painful than the

days ;

HISTORY OF DISEASES. 141

days J flow progrefs of all the iymptoms ; infen-
fible ten iVi nation towards the end of the third,
fourth, or fifth week. Mucous fever.

' Thefe three forts of fever, eftabliflied only by
abftradion, and which nature rarely exhibits in
that Hate of fimplicity, conftitute three principal
kinds, which have diftind chara6lers, and to which
may be eafily referred the numerous varieties of
fimple remittent fever. All the varieties of this
form of difeafe are fcarcely ever mortal, and are
cured fpontaneoufly at the end of a limited time.

Remittent fevers, like moil other afFe61ions,
may be often prevented or checked at their com^
mencement ; but, in general, they ought to be
refpedled in their progrefs, which feems to be the
flow method employed by the organization to re-
flore the deranged order of the functions. The
medicines and powerful topics employed with (b
much profufion during the progrefs of febrile
iymptoms, are for the moft part very prejudicial.

When a remittent fever has made its attack
completely, it requires the expe61ant mode of treat-
ment, and will not admit the application of any
means but fuch as are proper for favouring its na-
tural progrefs.

Simple remittent fevers, which are not cured
fpontaneoufly, are flowly changed into chronic
afFe6iions, or afllime the pernicious remittent form,
©f which we- are now about to fpeak.

206. Men

t4% REFLECTIONS djr THE

2,06. Men who inhabit a falubrious countf}'^
who take fufficient exercife, and who are properly
lodged, clothed, and fed, are rarely attacked by
fever. That which takes place, approaches more
or lefs to one of the three ty[)€s we have indi-
cated, according to the conilitution of the indivi-
dual, the ftate of the atrnofphere, &c. ; and is
never mortal. But in very po[Hilous cities, where
amidft poverty on the one hand, and opulence
on the other, a great many individuals are ener-
vated by exceflive fatigue, want of food, or food
of a bad quality, or by habitual idlenefs, and ex-
cefs of too fucculent noiirifhrnent j when the per-
Ibna debilitated by thefe caufe«, or in confequence
of a conftitution naturally feeble, of melancholy
mental aifedlions, &c. are attacked by a fimple
remittent fever, it is not uncommon to fee it airuine
the pernicious form» This form is charadlerized by
a weakened f3:ate of the functions of the fenfes;
proft ration of mufcular ftrength ; lofs of tone in
all the titTues ; an air of intoxication and ftupor,
delirium, &c. It generally terminates by the
return of health, or by death at the end of the
fecond, third, or fourth week. (Adynamic fever.,
Futrid fever.)

This fever is attended fometimes with Sfreat de-

rangement in the whole nervous action •, the func*

tionsof the various fyftems of organs are fomelimea

exalted, and fonjetimes almoft annihilated. All

4. the

HISTORY OF DISEASES. Hi

the iymptoms of this difeafe exhibit anomalies and
fudden changes. (Ataxic fever. Malignant fever.)

Pernicious remittent, like limplc fevers, may
be prevented on their approach, or checked after
their attack, by all thofe means capable of produ-
cing a fiirong fhockj or a powerful and continued
diftradlion* But when their progrefs is once com*
pletely eftablifhed, they ought to be refpedled.
All the aflive remedies, fo often employed, are
almoft always fatal : it will only be proper to
maintain the flrength by fome varied or tonic fti-
mulants, in order that the difeafe m<iy fpeedily
arrive at its termination.

The cauffe which mofl efFe(51ually contributes
to produce remittent pernicious fever is the exha-
lation of vegetable or animal matters in a llate of
putrefadlion, efpecially in debilitated and ener-
vated perfons, or perfons of a weak conltitution.
When this caufe is very extenfive, and has exer-
cifed its aciion on a great number of individuals,
it renders the difeafe epidemic. \x\ this cafe, the
iDJafmata difengnged from the furface, or from the
interior part of the bodies of the fick, reduced to
a ftate of extreme vveaknefs, become b. nev/ and
very powerful caufe of propagation ; and the
fever, which at fir ft was only epidemic, at length
becomes contagious. ^

In countries where the population is very great,
or where men are fubjeded to forced labour, by

ignorance

144 REFLECTIONS ON THE

ignorance and defpotirm, and often under a
fcorching atmofphere, or amidfl continual damp-
nefs ; thefe beings, who have food of a bad qua-
lity, or infufficient in quantity, without alkoho-
lized beverage, who are badly clothed, and who
refide in gloomy, damp, and confined huts, often
in the neighbourhood of vegetable or animal fub-
ftances in a flate of putrefa6lion, acquire a difpo-
fition highly favourable for the development of
this difeafe. It is obferved that it manifefts it-
felf more particularly in confequence of this
warVn, damp temperature, in which the body re-
mains without ftrength and without energy.

When it has given birth to a certain number
of pernicious fevers, they are then rapidly multi-
plied by the exhalations which proceed from thet.
difeafed bodies.

Thefe miafmata, when received into the lungs
of the furrounding perfons, produce in them an
attack of the fame difeafe, with the more facihty
as they are more difpofed to receive it 3 and thus
favour the progrefs of the contagion, which fpreads
with alarming rapidity.

In the courfe of this fever, the vital forces are
weakened to fuch a degree that the body feems
to refill only in an imperfe6l manner the laws of
chemical affinity ; and it indeed fhows fome figns
of decompolition differently modified by a rem-
nant of vital adion. In this point of view, the

phsenomena

UlSTORlr OF DISEASES. 145

plisenomena which take place in the whole organi-
zation may be compared to thpfe which occur in
a gangrened limb.

Pernicious fever, though at all times efientially
the fame, exhibits very diflindl charadters^ ac-
cording to the climate where it takes place, the
difpolition of the individuals whom it afFeds, the
infalubrity of the countries, the feverity of the
fymptoms, the greater or lefs rapidity of their pro-
grefs, &c. which produces differences obferved in
the different forms denoted under the names of
the Jail or hofpital fever ^ yellow fever ^ and plague t.
Thefe difeafes, efientially the fame, differ only
by fymptoms of little importance, and by compa-
rable degrees of intenfity. The hiftory of the
different peflilential epidemiae, and a more exadt
knowledge of the nature of this difeafe, fhow that
the plague cannot develop itfelf fpontaneoufly,
but in cities the wretched, ignorant and fuperfi:!-
tious inhabitants of which are confined in damp,
gloomy habitations, a prey to poverty and dirt j
fuch iis the inhabitants of fome countries of Afia,
Africa, and America. It may fhow itfelf, alfo, in
any country after famine, in towns in a fta-ie of
fiege, overcrowded hofpitals, occ.

The chemical compofition of the miafmata ex-
haled by pulmonary and cutaneous perfpiration,
and by the other excretions of bodies affefted

VOL. Hi. I. with

140 REFLEeTlrONS: O^^- •J'jajEf ,;

with this kind pf f^ver,4s -llill,;un.kno\vn j but,^iit,
is not probable that thefe mialiData can commu-
nicate the difeafe by their contaft with the fkin ;
nor does it appear that they remain long fixed to
articles which hayq been u fed by the infeded j
on the contrary,, they ^^eenirltQ evaporate with, the
greatefl facility. o 'bs^tb

If the miafmata of the plague could eafily re-
main attached to different articles, and be con-
veyed from one place to another, which is far
from being proved, it is probable that they might
be expofed, without danger, among civilized peo-
ple, who can procure by eafy labour the necef-.
laries and comforts of life, gDoiB'H^

The fpontaneous development of the epidemiae
of the jail fever, the yellow fever, and plague,,
which have taken place at different period^,
in .various eountrie.s of Europe, may. b^i. .mc)i:^,,
ealjly con ceiv:ed than fbe tranfportation from di-,
ftanjtj-egion^ of .^.fp^cific? virus capably of, produ-
cing them.

But there is no need of fuppofing this tranl^
portation, lince it is evident that the development
of a pernicious fever has taken place under a va-
riety-vQf.,circumflances. This fever may theu
afTume a very high degree of intenfity, by fpreading
itfelf to individuals weakened by every debilitating
caufe. The miafmata which then arife, from thefe
vx r ' ;, , , _y bodies^

HISTORY OP IMSEASES; 147'

bodies, enervated by wretchednefs and difeafe,
exHibit a charadler highly contagious, and pro-'
pagate the fever with great rapidity. '" '"' r

When the plague begins then to ri^aKe^^f^pici'
progrefs in countries where it does not frequently
ofccur, a general confternation prevails ; and the
dread of an evil, confidered as unavoidable and
mortal, difpofes the body for receiving the conta-
gion, and occafions more ravage than the dif-
eafe.

It refults from thefe confiderations, that the
fureft and fpeedieft means of checking the con-
tagion of an epidemic fever, which becomes in-
fedlious by the lungs, is to remove the lick imme-
diately from the city, and to place them under
tents, where there is a free circulation of air,
that the contagious exhalations may evaporate
with more facility, and be prevented from infe(5t-
ing thofe in the neighbourhood. Thefe confider-
ations lead us alfo to fome refle(5iions on quaran-
tine and lazarettoes. ^"

Thefe eftablifhments and inftitutibn^ wefeYoVfn-
ed at a period when there was juft reafon for
being alarmed by a horrid difeafe, the caufe of
which was unknown, and wtfjr* the progrefs of
which phyficians were very little acquainted, in
confequence of the imperfedt knowledge they
had at that time acquired of the organization. It
was therefore natural that people ihould fearch

L 2 for

148 REFLECTIONS ON THE

for and employ fuch means as were thought pro-
per for preventing a dlfeafe, which they believed
muft necefTarily be brought from places where it
frequently appeared, to others. where it v/as rarely
found. But it is very probable that fuch pre-
cautions are entirely ufelefs in regard to the ob-
ject propofed ; and that they would be rendered
fo by the manner in which they are employed,
even if what is apprehended could take place :
that is to fay, if the principles of the plague were
capable of adhering to merchandife, and of being
thus preferved for a long time in bales, in order
to be afterwards communicated by contaS:.

The government which, by exa(ft experiments,
which at prefent may be eafily made, fhall clear
up the qiieftion refpe61ing contagion, and by thefe
means convince the raofl incredulous and moH
timid, that no danger of this kind is to be appre-
hended, will be freed from a very great reftraint,
and may give new vigour to its commerce.

207. Intermittent fever exhibits different types,
according to the intervals by which the different
paroxyfms are feparated. The paroxyfrns return
periodically at the commencement of the fecond,
third, or fourth day, and furnifli the quotidian,
tertian, and quartan types.

Phyficians have obferved, that tertian fever
takes place under the fame circumiiances which

produce

HISTORY OF DISEASES.' 14g

produce bilious fever, and in individuals who are
mofl fabjecl to it, and that quartan or quotidian
f6Ve>' prefents a ftriking analogy with mucous
fester '; but this relation does not render it necef-
fery that internnittent fevers fhould be united
with the remittent.

Intermittent fevers Teem to be compofed of as
many Ihort difeafes as there are paroxyfms. They
may be checked at the commencement of each
paroxyfm, and thus fufFer much better hold to
be taken of them. It is in thefe fevers, therefore,
that cinchona has been attended with the moll
decided fuccefs.^

A paroxyfm of fever may be prevented, or im-
peded, by all thofe means which are capable of
profducing in the organization a new mode of
energetic action, continued for fome time : fuch
as a flrong dole of cinchona, opium, or wine,
given during the remiffion, or a little time before
the paroxyfm ; a very ftrong and acute dillrac-
tion, Sec.

During fummer, and in young perfons of a
ftrong conllitution, thefe fevers difappear fponta-
iieoufly after a fmall number of paroxyfms ; in
perfons of a weak conflitution, and during the
cold damp feafons, they are exceedingly obftinate.
When thefe fevers continue for half a year or a
year, they frequently induce chronic afFe61ions,

L 5 which

150 REFLECTIONS ON THE J

which flowly lead to a fiate of confumptipn that
in the end becomes mortal. iiixforfi n pi •

Intermittent fever has its pernicious form as
well as the continued. Its pernicious character
arifes from a peculiar and predominant fymptom,
the continued exacerbation of which produces
death at the end of the third, fourth, or fifth par-
oxyfm. It is in this form of fever in particular,
defcribed fo well by Torti, that it is proper to
make an early ufe of cinchona, to prevent a par»-
oxyfm which may become mortal.

Pernicious intermittent fever, as well as perni-
cious tertian and quartan, is epidemic, when in-
duced by exhalations from marfhes dried up toO'
fuddenly by the heat. The miafmata which arife
from thefe muddy bottoms, received into the
lungs with the atmofpheric air, produce on the
nerves of that organ an impreffion which .gives
rife to the ieries of febrile phaenomena. ? t^t -^d

The aftion of th^fe miafmata is more powerful
'6^ individuals not accuflomed to it, and who are
^ifi a weak flate of health. :Ji£9iib

'^ '^^Si' Anfinials ^fe fbfceptible ofl^experiencing
that general derangement of the fimftions which
conftitutes fever, with all that feries of fymptoms
which tend to bring back health. The fever, com-
monly renaittent or Qontinued, afTumes various

HlSTt)I«ri QF! !j>ISE A S E S, ] 5 1

forms accordi rig to their peculiar organization,
^nd to a thoufand other accedory cireumftances.
->: Among animals coll e(3;ed into herds or flocks,
as well as among men crowded together, the
fever aflTumes a pernicioas character, and becomes
epizootic, 'imiieonrequence of the fame general
caufes^iof infel^hrity. When it ,h§se#ade lome
progrefs, the miafmata which evaporate from a
great number of difeafed animals may in like
manner exercife a very flriking contagious influ-
ence on the lungs of thofe which, not b^ing yet
infeded, are much difpofed to become fori^ir-tP

The belief that the progrefs of epizootics could
be checked only by a general Jlaughter of the dif-
eafed animals muft, no doubt, have arifen from
ignorance in regard to this difeafe ; to its caufes,
and to its mode of propagation ; and the dread of

>Tnfe<^ion; has -been carried fo far. ^as to produce
orders for, the deftrud^ioH, of the hides, and of
dvery thing applied to the ujfe pf. the, eattl^j^
' It does not appear that animals experience the
difeafe under the remittent type, with paroxyfms
\vhich regularly recur ; and it is a very Angular

:^ecaliarity, that neither t^rtiajn jiprqviartatj 'fever
is obferved among theiD.3ra3gnBi^b fBt^nog isrft

smolqra,^) lQ.«t,noi ieriJ Ha dtiw, .-isva^ astmiilnbo.
'^^ -209^ AlmoU all the difeafe§i erf which a iliprt
view ftill remains to be given are^ owing to the

' circumftances of civilization, Thev confift in g

1. 4 derange-

152 REFLECTIONS ON THE

derangement of the nervous adlion/which may be
fafpended, weakened, increafed^ or changed.

Some of thefe afFedlions are produced by the
impreffion of foreign caufes ; but the greater
number are the refiilt of a bad ufe of the differ-
ent fundions. All thefeataxiie fhow themfelves,
for the moft part, without febrile fy mptoms.

210. The nervous adion is fufpended, in a
great liieafure, in afphyxia, catalepfy, fyncope,
and apoplexy, which conllitute the comatofe af-
fedlions. ' Corttata.

The afphyxiae arife, for the moft part, from
gafeous ^fubflancesj which when introduced into
the lungs produce on the nerves of tbatorgan an
a61ion ftill more violent thanihat of the miafma
of the plague ; and occafion'a general derange-
ment of the nervous a6lion, without' leaving any
traces of the affeftion on the organ iirft attacked,
Hence, in large cities, where fo man^"' caufes of
infedtion are accumulated,- the mialrnata which
arife under certain peculiar circumftances from
privies, tombs, common fewers, &c. ; the dif-
engagement of carbonic acid gas, which fo often
takes place in fermentation, combuftion, and, cal-
cination ; the nitrous and ammoniacal, &c. gafes,
received into the lungs, fuddenly produce vertigo,
convulfions, fainting, and apparent death, which
without fpeedy afliftance foon becomes real.

Thefe

HISTORY OP DISEASES. I53

Thefe difeafes, which are real polfoning by the
lungs, muft be diftinguifhed (torn the afphyxiae,
which take place in confequence of- the mere
privation of the oxygen of the air ; as when one
is immerfed in a medium in which none of it is
contained, and which however exercifes no pre-
judicial aftion on the organ of refpiratign : fuch
are the cafes of immerlion in water, in azotic gas,
or in hydrogen gas.

In the lafi: place, afphyxia may be produced by
the continued aftion of cold.

In every cafe of afphyxia, whether the difeate
has been produced by the interception of atmo-
fpheric air from the lungs ; by, the infpiration of
any gas not, proper for refpiration, or by that of
poifonous vapours ; or by the continued ad:ion of
cold ; it is always proper to remove the indivi-
duals, as fpeedily as poffible, from the 'caufes of
the afphyxise, and then to recall the vital aftion
by different ftimulants.

In afphyxia, the a6lion of the fenfes is fuA
pended ; refpiration and circulation are inter-
rupted, and the body differs from a carcafe only
vby the remains of heat. An individual may
fometimes be reftored to life after being in this
flate an hour, and even much more j but after at
longer period refufcitation is impoffible.

211. It appears that, in fome very rare cafes, a

violent

154 EEFLEGTIONS OW THE

violent mental affedion, a great dirappointment,
flrong indignation, ecilaiies and myftic contem-
plation, and particularly among women, may
lead to a ftate of ftupor and complete inleniibi-
lity, with permanency in the attitude in which the
iizdividuah were when attacked, or in that in which
they are placed hy others. It appears that this ftate
may continue twenty-four hours ; after which
fenfation and motion gradually return, as if after
Heep, without any remembrance of what took
placq during the catalepjy,

111. The ftate of fyncope, by which the indf-*
vidual is inftantaneoufly deprived of fenfation atM
motion, with a weaknefs and even complete fuf-
penfion of refpiration and circulation, feems to
arife from an interruption of the afflux of blood
towards the brain.
'-IThis interruption may be produced by a fudden
lofs of blood in a perfon while ftanding ; and
after all exceffive evacuations. It frequently re-
ftilts, alfo, from a fudden impreffion capable of
weakening or fufpending the adlion of the heart
and arteries ; which takes place in fome indivi-
duals debilitated by long difeafe, and particularly
in Ibme women, whofe weak Mhd irritable nei*ves
difpofe them for being ftrongly affedled by all
ftidden impreffions. . .i^- 1 i-^-; .i> . ..^^ - c . .

- 213. WeaK-

HISTORY OF DISEASES. 155

213. Weaknefs of the aAion of the brain feems
to produce apoplexy, which varies in its intenfity
from that announced a long time before by de-
rangement or palfy of feveral organs, to that
wfeif^hi' takes place fuddenly, and which ftrikes
like lightning.

t>'*jiVpoplexy frequently takes place in old age,
and feems to fhow itfelf in preference during
cold, damp weather, in individuals who have
fuffered by exceffive labour, and by the privation
of the neceflaries of life. Under certain circum*
fiances it has appeared epidemic, and in certain
places endemial. A difpofition to this malady
feeftis to he communicated by generation. It
frequently attacks men loaded with obefity j who
have a fhort neck and a large head ; who take
little exercifcj and who habitually indulge in an
excefs of food.

. Apoplexy may be produced alfo by compreffion,
agitation, and laefion of the encephalic organ.

This difeafe being for the moft part pi*o-
duced by weaknefs of the cerebral organ, blee,d-
ing and evacuants, fo frequently employ ed^ aye
almoil always hurtful, p^^st dfoiffw rR^iTeih"

Though the medical art furnifhes few refources
capable of oppofing an afFeftion generally followed
by relapfes, which at length become mortal, to-
nics and varied fiiimulants are the propereft means
for preventing the return of the difeafe.

Even

136 'REFLECTIOlsrS ON THE

Even if apoplexy were produced by an eiTuiion
of blood in the brain, bleeding would ftill be
hurtful, fmcc it could have no ciFed in regard to
the efFulion, and would deprive the patient of the
ilrength neceflTary to produce a reforption of any
effofed matter.

Bleeding is proper only in thofe few cafes
where apoplexy is produced by an afflux of
felood towards the head ; in forne adults of a
plethoric habit and ftrong conititution : in this
cafe it ought to be copious, and fpeedily em-
ployed.

The diftinftion of apoplexy into fanguine and
ferous is of no lignification. The ferous or fan-
guine efFufionSj obferved fometimes in the cra-
nium, are much rather the effecfl of the difeafe
than its caufe. Mofl of the other organic altera-
tions which have been found on opening the
bodies of perfons who died of apoplexy, either in
the cra,niumj the thorax, or the abdomeuj are
produced by the general caufes which conduft
llowly to apoplexy.

214. There is no iyftem of organs in which
the nervous aftion may not be interrupted, or
weakened, to fuch -a' degree as to be deprived of
the force necefiary for difcharging, in a proper
manner, the fundions affigned to it. This
Itaie of afilmla varies from flight debility to com-

' pleta

HISTORY OF DISEASES. 15^

plete palfy, and exhibits peculiar phenomena ac-
cording to the organs affefted.

In the mufcnlar fyflem, aflhenia produces
debility, tremor, and palfy ; and, according to
the parts attacked, St. Vitus's dance, torticollis,
aphonia, &c.

In the fyitem of the nerves, the eye exhibits
all the intermediate degrees between weaknefs
and paliy of the optic nerve ; which according
to fome peculiar charafters gives amblyopia, heme-
'ralopia,. nydlalopia, and amaurofis or blindnefs.

In the ear, the different ftates of afthenia of
the acouftic nerve give .various affeftions of that
organ, from dullnefs of hearing, in a greater or
lefs degree, to complete deafnefs.

The cafe may be the fame in regard to the
fenfes of fmelling, tafling, and touching.

Weaknefs of th6 nervous a6i;ion, in the fytlem
of digeftion, produces lofs of appetite, or ano-
rexia ; in the pulmonary organs, difficulty of re-
fpiration, or dyfpnea and afthma : in the fyftem of
generation, this weaknefs varies from dyfpsrma-
tifmus to impotence or anaphrodifia.

Pal fies are always incurable: the weaknefs re-
quires the aid of varied exciting medicines and
tonics, either applied to the organization in ge-
neral, or to the d§bilitated part.

215. The nervous a(fl;ian of our prgans, inde-
5 pendently

15S REFLECTIGN"^ ON tilt:

pendently of the different flates bf weaknefs of
which it is fufceptible, may contra6l alfo a griilt'
degree of mobility ; it may want proper fteadinefs,
and be habitually exercifed only with derange-
ment and di(()rder. It then gives rife to a ferisg '
of convulfive afte6\ions, fometimes continued, but'
almoft for the moft part intermittent, and always
fubjeft to periodical returns. Thefe affections ge-
nerally refult from a natural weaknefs of c6nll:i-
tution, a vicious education, and the improper ufc
of the voluntary fun6tions.

This particular flate of nervous action pro-
duces in the fyftem of circulation and refpi-
ration: palpitations of the heart, convulfions of
the larynx, cramp of the thorax, convulfive
aflhma.

In the fv'flem of digef1:ion it produces convuU
lions of the oefophagus, hiccup, vomiting, pains in
the f^omach (cardialgia) ; it gives rife to convul-
lions properly fo called, and totetanus; in the
mufcular fyflem this mode of derangement appears
in the whole of the organization, during par-
oxyfms of madnels, epilepfy, and byflerics.

In the lafl place, deVa:ngement of the nervods
a<5tion produces different diforders which are ob-
ferved in the intellet5lual fan6lidti^^''":^^K/V.

Moft of the convulfive xlifeafes have been cori-
lidered as local afFe6tions ; they however depend;
for the moft part, on a general derangement,

which

HISTORV OF DISEASES. lS0

which fhovvs itfelf, ia preference, in fome parti-
cular organs. .,

It is of. importance that we fhould here defcrlbe>
"vvith fome mlnutenefs, thofe general caufes ca-
pable of producing thefe nervous affe6tions, which
are become fo frequent in large cities among one
clafs of fociety. To comprehend thefe caufes, it
mull always be remembered that health is the re-
fult of a proper difcharge of the different func-
tipnsr.that thefe fundions mud be habitually
performed, as if each organ ought to confume a
determinate quantity of nervous action, which ab-
folutely requires to be ufed ; that the organs are
ftrengthened by moderate exercife, and weakened ^
by forced exercife and _ by reft, &c. In a vvordy
it mull be remembered that all particular affec-
tions, are jcapable of being tranfraitted, at leafl
in part, by the means of generation. ft-^§noi.

Thus, in the opulent clafs, women of a delicate-
conftitution, whofe weak and unfteady nervous ,;
adlion renders them fubjedl to what are called-
nervous affeiflions, experience in general difHcult-
parturition,, are. fubjeft ,.iOc,fcquent mifcarriages,
and. bring forth. weak. deUcate children like, them-
felves^^^^^.^^^, ^^^^^^-^-j^ j^g^g-jj-j^ 293uboiq uoit'^z

It is obferved, thatf/uch rchi-ldren are fubje^l. ta •
interruptions-in their fleep,fubfultustendinum3 and
frejqueiit colics; and that. their.dentition, : always
difficult, is, accompanied with convullVopSff &c. .

It

X60 REFLECTIONS ON THE

It is not advantageous for thefe children to be
fuckled by their mothers, who aflbciating them
to their manners an^J habits, ftipply them with milk
which affords little nourifnment, and which pof-
fefles the irritating charafter of the produfts of all
the fecretions, in a certain flate of weaknefs or
difeafe.

It would be much better if they were fent to
the country, and committed into the hands of
nurfes whofe limple manners and mode of life,
more agreeable to the laws of the organization,
would gradually corre6t their primitive dangerous
difpotitions.

But if they remain with their parents, the latter^
through a miftaken fondnefs, never fuffer them to
be abfent from their fight ; they do not allow them
a moment of liberty to take that exercife which
is neceflary for the complete development of their
organization. Being always near them, they ma-
nifefi; a continual uneaiinefs left their health
iliould be deranged. Thefe children, overloaded
with clothes, and particularly on the head, fed
in an improper manner, and deprived of exercife,
are expofed to frequent colds and often to horrid
eruptions. In confequence of an oppofite abufe,
we often fee other children equally delicate and
weak, kept habitually naked under a damp, cold
temperature, become fubjeft to catarrhal affec-
tions, and to rheumatifms exceedingly troublefome.

When

HISTORY OF DISEASES; l5l

When thefe children begin to grow up, the
parents, who never fuffer them to be out of their
fight, calculate with fcrupulous minutenefs the
refult of every ftep they make, and of ev6ry mor-
fel they eat. They repeat to them a thoufand
times a day, to take care of their health ; that
they will be hurt j that they are going to die of
hunger, or pcrifb by indigeftion. Thefe beings,
perpetually ftunned in this manner, gradually ac-
quire a habit of fear, and, notwithftanding the
pliability of their age, often become weak and
pufillanimous.

On the other hand, through a fear Of dif-
pleafing or vexing them, they are never checked
in their extravagant whims ; they are fufFered to
gratify all their caprices, even at the expenfe of
thofe around them ; and they thus acquire a habit
of obftinacy and domineering, to which they are
all ftrongly inclined*

Far happier are the children who are not reared
Under the immediate eye cf their parents ; nature
with lefs trouble fucceeds much better in deve*
loping their organs, and in forming their under-
ftandingSi

In another clafs of fociety, among the indigent
inhabitants of townSj children are aflbciated,
during their earlieft years, in the wretchednefs of
their parents, and the difeafes it brings along with
it. Thefe children are then educated under a

VOL. III. H • continual

l62 REPLICTTONS OF THE

^OBtiniial fear of brutal and b-Iind feverlty, fur-
, rounded by vulgar prejudices aiad the, moll abfurd
fuperflitions.

Thefe two kinds of education though in ap-
pearance diametrically oppofite, produce almoft
the fanye general refults.

As the children here alliuded to grow up, and
their intelle^lual powers- begin to expand, they"
aj?e foon coinpelled to remeniber things which
they do not underfland ; their minds are occupied
with nothing but the wonderful events of hiftory,
the abfurd fables of mythology, and the H3,yfi:eries
of religion. They are neven allowed to think,
for themfelves J and in this manner they are gra-
dually accuUonied to believe in things i-nconceiv-
ai)le and fupernatural.

During the firfl period of youth, childrren of
both /exes receive nearly the fame mode of edu-
cation ; but when they begin to approach the agie
of puberty their fituations are changed.

Boys are allowed, more liberty, and by proper?
exercife correcl, ia fome meafure, the vicious^ r^
fults of their firft education.

In a word, the inftru6iion given to them, relates
chiefly to literature and the fine arts; they com-
plete their ftudies v,?ithout having an idea of tlier
exacl fciences ; they are unacquainted with, the
reafon of any of the phaenomena. which daily take
place before their eyes, and in their organiza-
tion ;

HISTORY OF DISEASES. - l63

tioh ; they reftiain perfe6l ftrangers to every thing
aronrtd them ; fpericJ their lives like blind perfons
groping their way through farrounding objedls,
and ferve a contintral and unfruitful apprentice-
fhiip;

Thefe" menv however, who are niot deftined to'
th^ rt^echsmrcal aVts,- piwfue in foeiety different
dife^lions^-M' ^hiob it is of inhpoftance to follow
them.

Thofe who apply to. commerce and butinefs are
m a -fitCiatibn where they may enjoy pretty g6od?
health, if their occupations obligS" them to take'
proper daily exercife, and if they live with fobri'-'
dty a^rid temperance ; but xi/h'^ri they pafs the
greater part of their lives' iti' the connfing-houfe^
or in the clofer, and when th6ir principal enjoy-
rni6nts coniilt i'n the pleafutes of the table, they
always at lettg^th becorfte fubjedl^ to fome of thofe
nervous affe(5^ions of which we have already
fpoken. The ilow and continued progrCls of
thefe difeafes induces them to Confult all the
medical men with whom they arc, acquainted ;
and they generally follow the advice 6{ thofe who
give them the mod extravagant prefcriptibn^, and
thus often render their lituation much more dan-
gerous.

Thofe who purfue a military career in the
time of war, lead a kind of life exceedingly pro-
per fbf producing a ftrorig conliitution, provided

M 2 they

1(34 REFLECTIONS ON THE

they are able to fupport the fird fatigues, and if
thej live with temperance. Taking frequent and
ftrong exercife,, by which all the faculties may be
expanc!ed ; living alternately in different climates;
iifing all kinds of food ; ileeping often under
tents or in the open air ; and having no fixed
hours for repofe or for meals ; they are fubje6l to
no habits, and give to their organs all that ftrength
of which they are fufceptible.

This mode of life approaches very near to that
©f people in the hunter flate ; who have always
exhibited a very linking fuperiority of organiza-
tion.

, Thofe who devote themfelves to literature and
the fine arts are expofed to nearly the fame kind
of life as merchants, or perfons in office, and,
like them, are fubjecl to the fame affections ; for
the cure of which they are often feen to employ
the mofl improper means, while they negle(5t the
moft fimple and falutary.

It is very afionifliing, that thofe who produce
the mofi: admirable v^rorks in the imitative arts
fhould be entirely ftrangers to the principles of
philofophy, and often flaves to the moil ridiculous
prejudices.

Among fuch perfons, we often find fome whofe
luxuriant imaginations are always producing a
whimfical mixture of ingenious fi6f ions and agree-
able chimeras^ embellilhed by the beauties of
a dieiion..

HISTORY OP DISEASES. 1()5

di<5i:ion. Thefe amiable fook are received and
encouraged by the numerous clafs of the idle
and ignorant, whom nothing pleafes fo much as
the wildeft flights of the imagination, which they
confider as the flrongeft marks of genius.

In the laft place, there is a fmall clafs of idle
perfons, who, through a defe61 in their early edu-
cation, are left in a fituation ftill more difagree-
able ; they are gloomy, reftlefs, and continually
occupied with the feeble ftate of their health j a
prey to melancholy mental afFe(5lions : in this
manner they languifh for a long time, and at
length become hypochondriac.

Thefe unfortunate confequences of a bad early
education feem to have been felt only in a very
flight manner ; and it appears that the quefl:ion.
What is the befb education ? remains ftill to be
folved, for want of having been properly pro-
pofed.

The obje(5l of the flrfl: education oitght to be
to produce that development which is befl; fuited
to the whole of the functions, and to teach thofe
things which may be of the greatefl: utility
throughout life to the majority of citizens of the"
different clafl^s.

Thus, with the fiudy of one's mother tongue
and of the mathematics, a knowledge of natural
philofophy, chemiftry, and phyfiology, ought to
form the bafis of every good education,

M 3 During

l56 ■ REFLECTIONS ON THE

Dunng eduGation, care fhpujd be takerij by
varied exercifes, to favour, iii a proper proportion,
the development and llreMgtli of the mufcular
fyftem, of the organs of the fences, .^nd of the in-
telledual fun (9: ions; and it ought never to be for-
gotten that the predominance of a fuiicFtion alvvays
takes place at the expenfe of foms.e of the relt.

It will be proper in the different exercifes, as
well as in regard to meals and to fleep, to avoid
that daily regularity which, in the courfe of time,
renders men (imilar to thofe machines which can
be kept in motion only by winding them up
every day, at the fame hour, and in the fame
m_anner.

The bcft habit to be contradled is that of hav-
ing none. The empire of habit difpofes people
for being afFe^ied by every change and by all
fudden variations ; it Hkewife becomes an ob-
ftacie to new difcoveries, by confining thofe fub-
je<£l to its influence to the comnjon hackneyed
path.

a 1 6. Yptjng women, in the opulent clafs of
fociety, h^ve often fewer opporiunitjes of elcap-
ing from the baneful influence of a rxiijlakpn pdn?
cation : iq general, they are under much greater
reftrajnt than boys, and cannot fo eafily indulge
in that exercife which their ^ge requires. The
chief part of their attention i§ turned to the or-
6 nam.ental

HI^IJORy GF DISEASES, iQ'J

namentaJ parts of educati<jn ;f4h^^/;i"ienfibly ac-
quire a habit of indoience^aiad at length are
reduced to fuch a Itate that it is impoffible
for them (o be active. Their \\^k and delicate
organs acquire a high degree^of tifrritability, and
become exceedingly fenfible to the flighted im-
preffions. Some of them, even in their earlleft
youth, feel the confequences of this kind of life :
they are fubje^: to frequent indifpofitionj to flight
nervous affedlions, to frequent irregularities in
theexercife of their diiFerent funciions. Thefe
individuals, however, feem to enjoy good
health ,• have a frefh complexion, difplay perfonal
graces and talents ; poflefs great livelinefs, and
feem to unite all thofe qualities which are calcu-
lated to pleafe : but, in general, they refemble
plants cultivated at great expenfe in hot-houfes:
they often exhibit the fame glowing colours as
thofe which grow in the natural ftate; but they
have neither the fame vigour nor the fame per-
fume.

The exiftence, in fortie meafure artificial, of a
great number of thefe women, who have acquired
a habit of living in a date of the moft complete
idlenefs, is a circum fiance exceedingly curious in
phyfiology. If their fituation be minutely ex-
amined, even at a time when they do not appear
to be in bad health, it will be found that the
greater part of their functions are reduced to a
M 4 minimum

l68 REFLECTIONS ON THK

minimum of a6lion, and that fome of them ex-
hibit wonderful alternations of extraordinary de«
bility and exertion. Thus the mufcular fyflem,
which is incapable of habitually enduring very
gentle and continued exercife, is capable of over-!'
coming the greatefl; efforts in paroxyfms of hy^
flerics. The intellectual organ appears to be ex-?
ceedingly delicate ; it can fpeedily give birth to
the moft ingenious failles and repartees ; but the
attention cannot long remain fixed to the fame
object. The organs of the fenfes, pofTefling great
irritability, are difagreeably afFedled by all violent
imprellions ; by hideous forms, ftrong odours,
a harfh found, or the flightefl touch. All
fudden and unufual fenfations produce fyn-
copes, or other nervous afFedions exceedingly
dangerous.

Such females have fcarcely any appetite j they
take very little food, and prefer highly feafoned
aliments deflitute of nourifhment. In a word,
they are fubje(Sl to habitual coflivenefs ; the urln?
is fcarce, pellucid, and often inodorous ; perfpi-
ration is hardly fenfible ; the fkin is cool and
pale, and either void of odour, or emits a very
peculiar one; refpiration is fhort; the pulfe is flow
or accelerated, but habitually weak. The delire
of venery is either annihilated or tranlient ; there
exifi:s, for th^ moft part^ a habitual leucorrhcea.

If

HISTORY OF DISEASES, l6g

If this ftate be compared with that of a young
female whofe organs have acquired proper ex- '
panfion, a difference fo great will be obferved,
that it will fcarcely be poffible to conceive how
the phyfical faculties, among the former, could
be reduced to a permanent flate of debility lb
near a-kin to death.

The varied derangements, produced by the
want of occupation, or the bad dire6iion of the
nervous power in general, have been very frequent,
efpecially among the female fex, at a period not
very remote, when the numerous clafs of the
nobility, and thofe devoted to monaftic feclufion,
were condemned, by their lituations, to a ftate of
indolence, and when a fort of infamy was attach-
ed to bufinefs. This ridiculous prejudice induced
a great number of individuals to expofe them-
felves to great toil and labour during a part of
their lives, in order to acquire fpeedily, with opu-
lence, the noble privilege of flowly peri(hing by
languor, difeafe, and confumption.

It was among this clafs of the rich and the in-
dolent that the moft complete abufe of all th^
organic funfbions was obferved.

Hence the mufcular fyftem, which fo imperi-
oufly requires that its fundions Ihould be exer-
cifed, is condemned to abfolute reft in indivi-
duals who do not even take the trouble to walk.

The

J^O REFJLECTJONS ON TUB

Th€ table, decked out with profufion, prefents
highly flicculent food, proper for repairing the
lo(ies .they have not fuftained. Spiceries, which
ought to be united only with fubftances difficult
of digeftion, are combined with the extradls of
nutritive parts ; and yet thefe ftimulants become
necetTary for exciting the enfeebled organs, and
for procuring a few new fenfations.

The llomach, thus Simulated beyond meafure,
receives ufelefs aliment, on which it exercifes a
continual and laborious effort j while all thefe dif-
orders are increafed by the abufe of generous
wines and of fpiritous liquors.

In fome, the organ of reproduclion is incef-
fantly fiimulated by all the means which nature
or art can fupply ; and an immoderate ufe is
made of it, which tends fpecdily to confume life :
in others, a continence determined by civil or re-
ligious confiderations is engaged in a continual
llruggle Vv'ith all thofe means which are calculated
to excite venereal defires.

In a great many, the intelleclual organ is con-
tinually difordered by different pafiions, and by
the arts of imitatron or of the imagination. In
this ftate it may acquire an immoderate exaltation,
approaching near to madnefs, when not checked
by a fenfe'of focial duty, and by the prefent boun-
dAry_,.Qf,hiJi|}^|^. knowledge in ihe exact fciences.
"""'"'" ' '' - it

HISTORY OP DISEASES. iy\

It needs excite no aftonifhment, that fo de-
prived a Life of the iinoft Important of all the func-
tions fhoqld in the cpjurTe of tiijjg. produce to
great 4 era ngejTi e n ts. ■I'r'fi -id

Thele nerv',ou,s iafTediions, 3 part of which are
commonly dillingui(hed by the vulggr appellation
of th^e vapows, have by many bten confidered as
merely imaginary *, becaufe they often occur in
individuals who exhibit every appearance o( being
in perfect health. They however conftitnte very
painful difeafes, which at firft exift without any
organic alterations ; but which at length give
rife to changes of this kind, and thus become
combined with the afFe^ions which they produce.

Nervous affedions, in general, attack perfons
only whofe intelle61ual fundlions are kept in an
habitual ftate of adivity; which fuppofes the
cjontinaed adion of the different organs of the
fenfes, lince the intelle6lual organ ran combine
only fenfations which have been received.

Continual and almoft exclufive exercife of the
organs of the fenfes, and of the intelledtual func-
tions, tends to raife them to the higheft degree
c)f improvement ; but the other fyfreme of fonc-
tipnpj and particularly thofe of motion and digef-

* Young females, either from a defire of being fafliionable,
or of attracting more notice, have bceri feen to iinitate all
the manners of thofe really affefted with hyfterids, andby thefe
means become much fooner hjftericaL

tion,

172 REFLECTIONS ON THE

tion, if not fubjedled to proper exercife, become
weaketled ; and as all the organic lyftems are
conncifled, and have a mutual dependence on'
each other, it thence follows that as thefe organs
are weakened and deranged, the organs which
receive the fenfations, and that which combines
them, are deranged in the fame ratio, and at length
become incapable of performing their functions
with that regularity which they muft acquire by
long and continual exercife.

On the other hand, men who live in a conti-,
Dual ftate of apathy, without curiolity, without
fear, and without ambition ; who make only a
very limited ufe of the organs of fenfe and of the
intelledlual fundlions ; who place their whole en-
joyment in the pleafures of the table, and in in-
tercourfe with the female fex, are not fiibje6l to
thefe affeflions ; and may fpend the greater part
of their lives in a ftate of inaftivity without
any bad confequence to the organization : exer-
cife of the organ of generation is that which
fupplies, with moft advantage, a deficiency of
employment to the organs of loco-motion. When
fuch men have a ftrong gaftric fyftem, and employ
a great part of their time in digefling properly,
by leading in the lap of abundance a life merely
vegetative, they generally become loaded with
flefh, which is attended with all the inconve-
i^^iences peculiar to obetity.

During

^HISTORY OP DISEASES. ij^

During the courfe of the French revolution,
numerous examples occurred, which evidently
prove that all this order of di^eafes was merely
the refult of that idlenefs which prevails amidft
opulence and luxury ; and that exercife, ufeful
occupation, and a temperate life, are fufficient
to check its progrefs, and to bring back health.
Among the perfons crufhed amidft that na-
tional fhock were a great many debilitated fe-
males habitually fubjeft to difeafe : thefe indo-
lent females, compelled to fly, to take exercife,
to attend to the care of their exiftence and to
their fafety, and who were even conftrained to
begin to work that they might procure the ne^
ceiiaries of life, acquired in this aftive and labo-
rious ftate ftrength and energy, and ceafed to be
a prey to nervous afFe6lions.

It was from this order of difeafes that phyfi-
cians derived the grcateft benefit : thofe in vogue
maintained their carriages by the nervous affec-
tions of the opulent.

It was alfo by this order of difeafes that t/je art
of writing pref cript ions ^ which had become almofi:
entirely the whole art of medicine, was mofl: ex-
ercifed and improved. To be daily obliged to fee
patients, who conf|antly recited the highly varied
feries of the fymptoms of the fame affedion, and at
each vifit to prcfcribe fomething whi^h fhould have
the appearance of novelty, and which* at the
■ ^ fame

174 KEfS'LECTTdNS, ETC.

fame time, fliduld afford a certain degree of re-
lief, was a tallt which requifed a confiderable
fhare of fagacity. The prefcriptions, however,
for the refpedl paid to them were irfdebted to the
firange language in which they Were written,
and to the chara6iers which rendered them unin-
telho-ible.

END OF THE SECOND PART.

PART

' <.5[r!iJ ^rm.

PART THIRD.

VITAL FUNCTIONS.

VITAL FUNCTIONS.

ACTION OF THE BRAIN AND OF THE

NERVES.

3. We have examined the material ftru(5ture
of the lyftems of the different fundlions, in organ-
ized beings in general, and in man in particular,
giving a detailed defcnption of the forms, relation,
and ufes of the different parts of which they con-
lifl:, and we have added various phyfical obfer-
vations, with the refult of the chemical analyfis
made of them.

We have al fo given a hiflory of the deratige-
ments to which the different anatomical fyflems
of organs, the various fundi ions, and the organiza-
tion in general, are fubje(5l:. It therefore re-
mains that we flioald exhibit a view of the vital
phicnomena, in the organization in general, and
confider the peculiar fqnftions and reciprocal ac-
tion of each fyftem of organs,

a. In taking a general furvey of the whole

organization, we every where obferve veffels and

70L, iir, N nerves

178 VITAL FUNCTIONS.

nerves in fuch quantity, that it appears that the
whole organic flrudhire is compofed of only two
orders of parts_, which by their different interfec-
tions form numerous tiifues. In the cells or are-
olae of all thefe tifllies are depofited the albumi-
nous, gelatinous, adipofe, faline, Sec. juices, of
which the veflels and nerves themfelves are com-
pofed.

The vefTels form almoftthe whole of the tifllies 5
they convey the materials intended to ferve for the
nutrition of all the parts, and carry back the re-
fidue of all the fecretions. The nerves diftribute
the principle of adlion to every part, fo that the
heart and the brain, the principal centres of thefe
parts, are evidently the moft important organs.
The cerebral fyfiera and the nerves ought, how-
ever, to be coniidered as the organs mofl eflential
to life ; lince they diftribute the principala^lion
to every pait of the body.

It refults from thefe principles, that the dif-
ferent fyftems of organs which efTentially confill
of tiiTaes, formed by the veilels, may be conii-
dered, in general, as infiruments ; and the nerves
which are diftributed thither as the power which
puts them into a£lion.

We fliall lirfl: confider the general povv^er of the
organ v»'hich communicates- motion ; and then
examine the a6lion of the different infiruments
which it puts in motion,

' ' j.The

Action of the brain and nerves, jyg

3. The cerebral and nervous fyflem are efTen-
tially compoled of the encephalon, the rachidian.
prolongation^ the trifplanchnic, and the nerves '.
which are continued with thefe parts, and which
are diflributed to all the organs.

The perfedibility of the cerebral organ Teems
to depend on the fize of the encephalon, and on
the tenuity of the nerves. We obferve, indeed,
that the encephalon of man is proportionally
larger than that of other animals ; and that his
nerves are fmaller and more numerous. The lize
of the furface of the brain is increafed by its nu-
merous and profound anfra6luofities. The differ-,
ent fe6lions made in that organ exhibit a great
many eminences, cavities, and flrata of various
forms and colours, with the ufes of which w« are
unacquainted, but which are evidently more nu-
merous than in that of other animals. In a word,
it is obferved that the cerebrum, the cerebellum,
and the mefencephalon of man are lefs diftin6l,
and feem tD be more confounded, than thofe of
other animals.

The encephalon is not„ a pulpy mafs, and
every tbjng feems to give us reafon to believe
that it is a vSry important organ of fecretion;
It is indeed obferved that it receives about a fixth
part of the blood, which is conveyed from the
lungs by a very fhort paflage ; the cerebral arte-

K 2 ries

'■*..-'v ^vi

150 VITAL FUNCTIONS.

rles are uncovered, that is to fay, have no cellular
tunics i they exhibit frequent anaftomofes; arc
indefinitely ramified over the large furface of the
brain, then enter the interior part of it, and im-
mediately difappear.

It is not improbable that thefe arteries, by their
indefinite divifion, are foon changed into ferous
veflels exceedingly fmall. The blood then returns
from the encephalon by numerous tortuous veins,
which depofit it at certain intervals in finufes,
where it remains for a longer or fhorter period.

The encephalon gives birth to twelve pairs of
nerves, which are diftributed to the face, to the
cranium, to the neck, to the breafl:, and as far
as the flomach. Of thefe nerves the optic and
the ethmoidal arife from the brain, and the refl
from the mefencephalon : none are furnifhed by
the cerebellum.

The rachidian prolongation gives thirty pairs
of nerves, which ifTue through the vertebral holes,
and are diftributed to the neighbouring parts.

The trifplanchnic gives birth to the nerves
which are eflentially diilributed to the organs of
circulation, of digeftion, and of refpiration. The
encephalic and rachidian nerves form, by their
union, the nerves of the limbs.

In the laft place, the nerves of all the parts
have a communication with each other, and

with

ACTION OP THE BRAIN AND NERVES. 181

with the encephalon, in a manner more or lefs
diredl.

This lliort view, though very incomplete, Ts
fufficient to fhow by analogy, that the brain
mufl perform a very important fundiion, lince it
is furnifhed with every thing neceffary for the
moft perfe6l organ of fecretion ; that its fecre-
tion muft be efFefted by means of veflels fo
fine, that the long capillary canal of the tefticle
exhibits only a very coarfe model of them, and
that the refult of this fecretion mull be a fluid
exceedingly rare.

Thefe few obfervations, refpeding the anato-
mical fi:ru6lure and diftribution of the cerebral
and nervous organ, though not fufficiently fatis-
faftory, may ferve, when united to accurate obfer-
vation of the phjEUomena of life, to give a pretty
extenfive idea of the function which it performs,

4. Every part of the organisation confifts of
a tifTueof veflels and nerves, in the interftices of
which are depofited liquid or folid fubftances of
different natures ; and under this point of view
they may be coniidered as fo many organs of fe-
cretion and excretion. The moleculae of matter
which enter into their compofition are continually
dillipated, and their place is fapplied by others
which infenfibly afiume a peculiar arrangement.
Paring this procels, the organic and living part

N g always

IS'J VITAL FUNCTIOKS.

always jofes, by the inert matter depofited in thefe
interftices,, fo that at length the latter impedes
the vital a61ion, the organ then dies, and becomes
fubjedl to the empire of general affinity.
■ This vegetative or animal life, peculiar to every
part of the organization, is performed by means
of veflels which convey to them the materials of
nutrition, and carry back the products of the fe-
■ cretions. The a61ion of the veffels is maintained
by the prefence of the nerves which accompany
them, and which proceed in a particular manner
from the trifplanchnic. ^ch feems to be the ge-
neral mode of the vitality of a great number of
vegetables and animals, each part of which is en-
dowed with its own peculiar kind of life, without
forming a necetfary and conftituent part of a
whole, and may feparately procure to itfelf the
materials of its nutrition. Thefe beings are fuf-
ceptible of divifion, and are eafily reproduced
from flips.

But in bodies of a more compound organiza«.
tion, and particularly in man, each living part
forms a portion of the whole, and contributes to
the formation of tho. d\&Q.vQntJ}Jiems of organs.

The f)fl;ems of organs perform the fundlions
peculiar to them, by means of particular nerves,
and thus enjoy a new life. This organic life is
that Vvhich is of the greateft importance. Thus a
mufcle is compofed of a tiflue of veiTels^ v;hich has

its

ACTION OF THE ERAIN AND NERVES. 183

its proper life of nutrition. Thefe vefTels, by their
contexture, form bundles of fibres fufceptible of
contradlion ; and this contraction is performed by
means of particular nerves. If thefe nerves are cut,
contraction no longer takes place ; bat the muf-
cle continues to live.

The nerves which give vitality to the vefiels are
furnifhed to them by the trifplanchnic : thefe
nerves expand in the abdomen, over the principal
trunks, and accompany them in all theif divifions
and fubdivifions. The vefiels then can no longer
be feparated from the nerves ; and carry every
where with them, their principle of adlion.

The nerves diftributed to the different fyftems
of the organs come from the encephalon, or its ra-
chidian prolongation, in large trunks Cufceptible
of accidents, and on which experiments can be
made.

It has indeed been obferved, that as foon as a
nerve has been cut, or a ligature has been formed
on it, the fundion of the organ to which it is dif-
tributed immediately ceafes.

A nerve Vv'hich has been cut is captible of cica-»
trizing like other parts, and of gradually reluming
its a6lion *.

If the mufcles of an animal, recently killed, be

* See Haifjhton's experiments on this fubjeft in the Tranf-
aftions of the Royal Society of London for 1795.

jsr 4 irritated

184 VITAL FUNCTIONS.

irritated by the point of a fcajpel, they contrad for
a lonp-er or fhorter lime, and then ceafe to nnove j
if they be fuffbred to remain at reft during a certain
period, and be then irritated, they again contra£t,
but in a weaker manner, and at length ceafe to be
afFeded by the point of the inftrument : but if ex-
cited by any other irritant, fuch as the Galvanic
fluid, by making them form part of a Galvanic
chain, they are once more feeri to exhibit contrac-
tions : but at laft they become entirely motionlefs.

It vi^ould appear from this feries of phasnomena,
which the mufcles exhibit while irritated, that irri-
tation makes them gradually lofefomething, which
at length becomes completely exhaufted.

It is obferved, in animals, that the contraction is
in general more fenfible, as death has been fpee-
dier ; and there is no contraflion when they die
flowly after long fufFerings or violent convulfions,
during which the nervous a61ion has been com-
pletely exhaufted,

5. The regular and fimultaneous exercife.of
the adlion peculiar to each tiflue {a?iimal life), and
of the action peculiar to the different fyftems of
organs, which form thefe tifTues {organic life), con-
ftitute life and health.

It appears as if the cerebral lyftem, in the ex-
ercife of its fundlions, fecreted a fluid analogous
to the eledric fluid j as if it diftrihuted this fluid

to

ACTION OF THE BRAIN AND NERVES. 185

to every part of the body, by means of the nerves,
which ferve it as condudlors ; and as if it commu-
nicated to this fluid a peculiar movement, in con-
fequence of which each organ performs the func-
tion afligned to it.

The hypotheiis of a nervous fluid, though high-
ly probable, and as we may fay necefTary, ought
to be conlidered only as a convenient method of
explaining fa61s which cannot be difputed.

In the exercife of its fundion, each organ feems
to draw off, and to confume a part of this fluid.

This fluid, deflined to be employed in an uni-
form manner by all the fyftems of organs, may
be employed by the forced exercife of one : in
this cafe, the reft, without having been expofed
to any exercife, are reduced to a Hate of inftan-
taneous laflitude. •

The nervous fluid, confumed during the exer-
cife of the funftions, is repaired by reft.

The nervous fluid, which is fecreted, abfolutely
requires to be employed : when not habitually
confumed, its readlion produces, in the different
organs, derangements more or lefs ferious.

The imprefiion made on the organs by the
eontadl of foreign fubftances produces a change
of aflion, more or lefs ftriking, according to the
nature of thefe fubftances, and the ftrucilure of
the organ which has been touched.

The impreftion received gives to the nervous

fluid

180 VITAL FUNCTIONS.

fluid of the part a movement, which is propagated
as far as the brain : the a6iion of the latter is then
augmented or changed.

The movement of the reaction of the brain is
immediately tranfmitted to the part which has re-
ceived the impreffiqn, or to any other particular
organ, or to the whole of the organization^ and
produces varied phaenomena.

When the natural a6lion of the parts is pro-
perly Itimaiated, a fenfation of ea[& is the refalt %
and when the fandlions are deranged a fenfation
id{ pain is experienced.

This fenfation appears always to be the refult of
a reaction of the encephalic organ.

The phenomena of life arc maintained by the
prefence of different natural ftimulants, fuch as
heat, the air, food, &c. Thefe fabftances, by
Simulating the nervous a6}:ion of the organs, fup-
ply them with the materials neceflary for the exer-
cife of their functions.

When an organ has been fubjeded to the ac-
tion of a flimulant, the refult may be two. phasno-
mena very diftin6l : ifl. The part performs; in a
manner more or lefs apparent, the fundlion pecu-
liar to it : 2d. The individual is confcious of tiie
impreflion received.

Every organ which is ftimulated tends to per^
form the func^tion peculiar to it.

When the different organs of an animal, re-

ceRtly

ACTION OF THE BRAIN AND NERVES. 18/

cently killed, are irritated by a powerful ftiinu-
lant, each of them receives the impreffion, and
anfvvers to it, according to its own manner. When
the irritated organ, in confequence of the relation
between its parts being deftroyed, cannot dif-
charge the fundion for which it is deftined, it al«
ways receives the impreffion, and the latter is then
tranfmitted to diftant organs, where it may be-
come apparent.

The organic fvilem, on which the a6lion of
ftimalants is exhibited in the moft evident man-
ner, is that of the mufcles, becaufe its fundion
is to produce motion.

If an animal, recently killed, be placed in fuch
a fituation that its different organs are interpofed
in the chain of a ilrong Galvanic pile, the muf-
cles become convulfed, the bladder contradls, the
inteftines perform a fort of periftaltic motion, the
motion of the heart is accelerated, &c. In organs
which cannot execute the fun6lion peculiar to
them, or which perform that function without any
apparent motion, fuch as the liver, the fpleen, the
kidneys, the ovaria, the matrix, &c. the impref-
fion is alfo received, and when ftrong is tranfmit-
ted to the mufcles of the pelvian limbs, which,
in this cafe, are violently contrafted. Thefe ge-
neral truths are fufficient to enable us to form a
jufl eftimation of every thing that has been faid on
the fubjedl of irritability,

Co ijCioufjiefs

188 VITAL FUNCTIONS.

Confcionfnejs of the impreffion received, or ^^n-'
fation, appears, as already faid, to be the refuit
of a readiion of the cerebral iyftem. Hence, when
the natural relation is not interrupted, and when
an organ is ftimulated, the impreffion is tranfmit-
ted to this iyftem of organs; and according as the
movement of reaction is regular, or as it is per-
formed with trouble and diforder, the individual
experiences a flate of eafe or of pain. Thefe
obfervations may ferve to account for the aume"
rous phcenorioena o( fen/ihility,^

ACTION

[ 1S9 ]

ACTION OF THE BONES.

6„ The folid fupport of the body is formed by
the bones, the arrangement of which determines
the form of the individual, in the ftrudlure of the
ikeleton.

The flceleton is effentially formed by the trunk
and the limbs. The trunk is compofed of three
diftincl parts, the thorax, the head, and the
pelvis : thefe three parts are united by the verte-
bral column.

The thorax contains the principal organ of cir-
culation and thofe of refpiration ; the head con-
tains the cerebral organ, which is continued along
the rachidian cavity ; and the pelvis receives or
fupports the principal organs of digeflion and
thofe of geftat ion. The bones of the limbs, as
well as thofe of the trunk, afford points to which^
the mufcles deflined to move them are attached.

7. The different pieces of tlie ikeleton are
united different ways : fome are fitted into each
other by indentations ; others are united by plane
furfaces j but the greater number are articulated
by fmooth, round, and excavated furfaces.

In

IQO VITAL FUNCTIONS.

In tbefe different modes of connection, tlie
furfaces are fometimes covered only by a thin
membrane, as in the bones of the cranium, fome
bones of the face, and the teeth* For the moft
part, they are incrufted by a cartilaginous fub-
Hance of greater or lefs thicknefs, and exceed-
ingly elaftic ; as is the cafe with all the moveable
articulations : in the laft place, a cartilaginous
plate is found between the articular furfaces of
the bones of the (boulder, of the knee, of the
jaw, &c.

The bones joined by indentations or by plane
furfaces, without cartilaginous incruftation, are
entirely motionlefs ; others perform movements^
which vary from the very obfcure motion of the
-iones of the pelvis, of the vertebral column, of
the tarllts. and metatarfus, to the very extenfiv*
movements, in all diredions, performed by the
bones of the arm on the fhoulder.

The moveable articular furfaces are enveloped
by a membranous capfule, and fecured by m^ans
of ligaments.

The articular and capfular furfaces fecrete a
vifcid albumino«s liquor (fynovia), which renders
the motion fofter and eafier. This liquid is takeu
up by the abforbing vefTcls, and is continually re-
newed.

The fecretion and abforption of this liquid are

maintained

ACTION OF THE BONES. \gl

jnaintalned arid excited by motion : perfe6l and
long continued repofe produces, at length, an
ancyiofis.

8. The {yCtem of the bones is compofed of
the bones properly fo called, the membrane by
which they are enveloped, and the marrow con-
tained in their cavity.

The half of the mafs of the bones is compofed
of veflels, nerves, gelatine, fibrous matter, Src.
The veflels, by their interfedlion, form cells or
areola, in which the hard part is depofited.

The marrow is compofed of a vafcular and
membranous reticulation, the vacuities of \vhichi
are filled by a greafy and albuminous fluid.

The vefTels and the nerves which proceed from
the periofteum, and thofe which traverfe that
membrane, penetrate into the fubftance of the
bones, and are continued with the vefiels of that
part, thofe of the interior periofleum, and thofe
of the marrow.

The organic and living part' is compofed of the
aggregate of all thefe vefTels and nerves; and the
phaenomena of oflification refult from the circu-
lation, the fecretion and abforption which they
continually exercife.

The hard part of the bones is compofed of
phofphate and.- carbonate of lime : the latter fait
is in the proportion of a tenth.

7 Tbe-

ig2 VITAL FUNCTIOM.

The gelatinous or albuminous bones in the
germ, pafs like all the other parts to the fibrous
or filamentous ftate in the embryo^ and become
cartilaginous in the foetus.

The cartilaginous fiibfiiance gradually difap-
pears during the lafi: months of geftation, and
during the firft year of life, to give place to the
faline matter^ from which the bones derive their
folidit}^

The cartilaginous or ofi^ous ftate begins by
points, like a kind of nuclei, around uhich are
accumulated moleculce of the fame nature : thefe
cartilaginous or ofleous points, by increafing,
reach each other, unite, and are at length con-
founded.

There are three points of offification for the
long bones ; one, and frequently feveral, for the
fhort bones.

9. The bones when they become folid do not
remain in that ftate : the molecule of the phof-
phate and carbonate of lime, or their elementary
parts, are continually difllpated, and replaced by
others, which always afilime a different arrange-
ment ; and in the courfe of this procefs the ac-
cumulation of calcareous falts encroaches on the
vafcular tifiue of the bones.

It is indeed obferved, in infancy, that the bones
are reddifh and pretty flexible ; at the adult age

they

ACTION OP THE EONES. JQ3

they become more compafl:,.and aflume a bluiih
colour ; in old age they are dry and brittle, and
exhibit a yellow afii colour,

If an animal, the bo:v- 1 of which are flill in a
ilate of growth, be t'cd *'ov forne time on mfidder,
the bones bejoose covered with a rofe-coloured
ftraturn on the outiide ; if the i^fe of this food
be afterwards fufpended, they become covered
with a new white ftratum, aiid the rofe-coloured
llratum is more and more covered in the courfe
of years.

On the other hand, it is obferved, that the ca-
vities of the long bones increafe in fize as the in-
dividual grows older.

It has hence been fuppofed that there is reafon
to conclude, that bones which increafe in length
and in breadth by development, increafe alfo
in thicknefs by concentric flrata on the outiide,
and that the long bones are dellroyed in like
manner by concentric ftrata in the intide of their
cavities, which confcquently increafe in fize.

lo. In the phaenomenon of the coloration of
the bones by madder, we muft not imagine that
the coloured moleculae of that plant are depofited
on the bones to give them a rofe' colour; nor
rnuti we believe it to be abfolutely necefiary that
thefe moleculae fhould be conveyed to the bones
to change their habitual mode of adlion.

VOL. III. o Foreigin

194 VITAL JUNCTIONS.

Foreign fubflances do not circulate in tni^
manner in the organization ; and thdfe bodies
fuppofed to be lufc^ptible of penetrating thither
fb eafil)', are not found in the different parts.

The a(5lion of the madder on the digeflive or-
gans produces a rnode of adlion, psrticularly re-
maikoblej li tLa fecretion of "ihe ofieous fub-
flance, ?.r ^ ■ . 3n in the fecfetion of milk ; but the
chyle 'lie ought to be the natural medium for
conveying the madder into the mafs of ihe hloodj,
and thence into the bones or the udder, aillimes
no colour by the ufe of this root,

II. The bones become difplaced, or are fub-
je6^ to luxation, with greater or lefs facility, ac-
cording to the nature of their articulation.

A knowledge of the relation of the articular
furfaces and of the foft parts by which they are
furrounded, is fufficient to determine in what di-
reftion luxations may take place : they are fuf.
ficicnt alfo to determine the forces proper for re-
ducing them.

Luxations are .reduced with greater eafe the
more recent they are : they may however be re-
duced even when of long ilanding, but with
much more difRcalty.

When a bone remains in a ftats of luxatioOj,
th-e preiTure and motion of its head give rife
ibmetimes to the formation of a new articular

capfule^

ACTION OF THE BONES.* jgS

capfule, at the expenfe of the neighbouring foft
parts, which in the courfe of time aflumes a car-
tilaginous and even ofleous texture : in this man-
ner there is formed a new articulation, which ad-
mits only of very confined movements.

o 2s ACTION

[ 196 ]

ACTION OF THE MUSCLES.

12. 1 HE mufcles are formed of fibres in bun-
dles : each fibre is compofed of feveral fmall
fibres, and the fmall fibres are fubdivided into
others ffill more minute. This indefinite fubdi-
vifion, the termination of which cannot be per-
ceived hy the beft infiruments, renders it impof-
fible for us to know v/hat the nature of a fimple
fibre is.

The mufcles^ the bundles of fibres, the fibres
and fmall fibres, are feparated by a covering of
cellular tifi^ie, in which are accumulated thofe
albuminous, gelatinous, and adipofe juices, a
greater or fmaller quantity of which conftitutes
the ftate of leannefs or fatnefs.

The mufcular fibres, when flripped of all their
coverings, exhibit, in their decompofition, a great
deal of gluten or fibrous matter, a fubftance found
only in the red part of the blood.

The,mufcle§ are of a reddifli colour, and are
terminated towards the point Vv'here they are at-
tached by a very clofe fibrous tiflue,, of an en-
amelly white colour, exceedingly elaftic, much
lefs voluminous than the body of the mufcle, and
which aiTumes the form of cords or bands.

* * • ■ ^ Theie

ACTION OF THE MUSCLES. 1^7

Thefe white fibrous parts, which conftitute
the tendons and the aponeurofes, are eflentially
formed of gelatinous fubftance ; and by decom-
polition they do not furnilli gluten.

13. When a mufcle is irritated, its fibres be-
come fhortened, contrail, carry with them the
moveable points to which they are attached, and
thus produce the different motions.

The mufcles begin to contra61 in the firfl: pe-
riods of life, by the irrefiftible tendency to mo-
tion which is experienced in the different flates
of unealinefs, or of want ; but they gradually
affume the habit of a more regular ■ exercife,
and their being kept in continual ufe gradu-
ally develops that force, pliablenefs and dexte-
rity of motion to which they are capable of
attaining.

The force of the mufcles, in general, is in
the ratio of their t hicknefs and of the length of
their fibres.

The mufcles, for the mofl: part, a6l in a very
unfavourable manner ; they have a dire6lion al-
moft parallel to that of the limbs ; they are at-
tached very near to the centres of the articula-
tions, and their power being frequently placed
between the point of fupport and the refiftance,
they form a lever of the moil difadvantageous
kind. ' ,

o 3 The

TITAL FUNCTIONS.

The ordinary force of the mufcular allien has
been meafured in a pretty precife manner *; but
under fome circumftances this a6lion exhibits
inconceivable energy, which it is impoffible to
appreciate. ~

The mufcles, under fome circumftances of life,
overcome a refiftance by v^^hich they would be
broken in the ftate of death. It is aftoni(hing to
fee weak, delicate women, who are habitually
without energy, exercife, during paroxyfms of the
hyfterics, convulfive motions which can fcarcely
be moderated by the mofl vigorous men. A
llender delicate arm has frequently broken the
Urongeft cords, dragged the heaviefl bodies, and
thus produced efforts which could not have been
performed by the robuft arm of a man in a ftate
of coolnefs.

The ftrength of the mufcles, the pliability and
dexterity of their movements, are increafed by
moderate exercife and the power of habit. Every
body knows to what a degree of perfection the
mobility and precifion of the movements of the

* It refults from experiments made with the dj'nanometer, by
C. Regnier, that a man of mean ftrength, when ftanding per-
feftly ereft, can raife a vt'eight of 265 pounds, and that he can
fqueeze any thing between his hands with a power equal to 10a
pounds.

Men and horfes may labour a whole day and exert one fifth
of their abfolute ftrength.

' ' mufcles

ACTION OF THE MUSCLES. igg

mufcles of the limbs, and of the throat, may be
carried' in tumblers, rope-dancers, and in parti-
cular fingers ; and it may be readily conceived
how unfatisfac^ory every chemical or mechanical
explanation of this at^ion mud be.

The mufcles fcarcely ever act fingly j and their
different motions are always owing to the fimul-
taneous or rapidly fucceflive adlion of a greater
or lefs number. The indefinite combinations, of
which their adlion is fufceptible, give to the limbs,
by long exercife and the force of habit, the faculty
of moving with an agility and a precifion truly
wonderful,

Almofl: all thefe movements are thofe of fle6iion
or extenfion : the flexor mufcles are called the
antagonifi:s of the extenfors ; and the former are
always ftronger than the latter, fo that the fi:ate
of reli, of relaxation, or of equilibrium, is found
in femi-fle£tion, a ftatc which the limbs naturally
afibme during fleep.

When the flexor mufcles contrail, the adVion
of the extenfors ceafes, and vice verfd: during
their concradlion, the mufcles become (horter and
thicker, and form a projection which refills the
preiTure of the hand.

The mufcles, which are habitually exercifed,
become more voluminous, alTume greater cQnfiit-
ence and tenuity, and their colour becomes
darker. Thefe organs, like all the reft, exercife

p 4 their

200 VITAL FUNCTIONS.

their fun(5ions by the influence of the nerves
which feeni to convey to them the principle of
a6^ion4 By long continued exercife the mufcles
tonfume this principle of a6lion ; it even appears
il.j-i they can draw it off from the other organs,
and thus reduce them to an inftantaneous ftate
of laffitude, which renders it impoffible for them
to ad.

14. The greateft proof that men are eflentially
bipedes is. that they all walk on their two feet.
We muft not, however, believe that this exercife
is lo natural and fo familiar to them, that they
can alL perform it with the fame facility. This
excrcilbj as well as that of the other organs, re-
quires a fort of ftudy, before it can be performed
with all the advantage poffible.

Standing is not a ftate of repofe^. but the effedl
of continual extenfion. In this polition the bead,
which has a flight tendency to incline forwards,
requires to be kept back, and the whole body
fixes itfelf in. fuch a manner that the centre of
gravity falls between the two feet ; the fhoulders
are thrown fo much the more backwards as the
abdomen forms a more conliderable projection :
this is particularly obferved in the ftate of preg-
nancy.

During the firft year of life, children cannot
fland upright, becaufe their pelvian limbs are

ftill

ACTION OF THE MUSCLES. 201

mil weakj fhort, and proportionally ilender ; be-
caiife their head and abdomen, which, compara-
tively fpeaking, are exceedingly voluminous, in-
cline more ftrongly forwards; and becaufe their
vertebral colnmn has fcarcely any curvature;
but in the fecond year this difpoiition gradually
decreafes, the child makes an effort to Hand^
keeps itfelf upright, and tries to walk.

SENSATIONS.

[ 202 ]

SENSATIONS,

15. Before we proceed further in explaming
the phasnomena of our different fun(^ions, it will
be proper to examine the general adlion which
foreign fubftances have on our organization ; and
this will naturally lead us to the organs of the
fenfes, which bring us into relation with fur-
rounding objedls.

The bodies which touch us excrcife an action
on our organs in proportion to their mafs, their
velocity, and the chemical affinity of their mo-
Jeculae j and according to the peculiar ilru61ure
of the parts fufccptible of being alleded in a
direct or an indirefl manner.

The firfi: body which exercifes, an aftion on os
by its weight, and which continues to a6l at every
moment, is the atmofpheric air : its preffure on
the whole furface of the body is enormous. But
we are not fenfible of this preffure, becaufe it is
continued ; becaufe the air which furrounds us is
in equilibrio with that in the interior of our or-
gans, and becaufe the fluids which, in a great
meafure, compote the material part of our organi-
zation, have need of the preffure of the atmo-

fphem

SENSATIONS. 203

iphere to keep them in the ftate of liquidity which
renders them fit for that purpofe.

The atmofpheric air, as well as all other fluids^
exercifes an equal preflure in every diredlion ;
and its weight is in the ratio of its perpendi-
cular height and the breadth of its bafe. The
furface of the body has been efti mated at about
1400 fquare feet ; confequently we experience
from the atmofphere a prelTure equal to that of
a column of mercury twenty-eight inches in
height, and having a bafe of 1400 fquare feet,
which makes about 30,000 pounds : an enormous
weight, which, were it not for the reafons already
nientioned, would crufh us to pieces.

16. This preffure, to which we are habituated,
becomes to neceffary, that we find ourfelves much
indifpofed when we afcend to the top of a moun-
tain, where it is much diminifhed.

When the prefTnre of the atmofphere has been
confiderably increafed, it produces a reftraint
which cannot be long refifted : this is what takes
place under the diving bell,- when a perfon de-
fcends to a confiderable depth.

17. All other heavy mafles, which exercife on
our bodies an accidental action, may, according
to their weight, bruife, crufli, or deftroy us ; and
thus produce accidents more or lefs dangerous.

Bodies

204 VITAL FUNCTION'S. .

Bodies which ftrike us exercife a Wronger ac-
tion, according as their velocity is greater, and
as the parts are lefs fitted or have had lefs time to
yield to the fhock.

All the molcculae of bodies exercife an a6tion
on each other, called the force of affinity. This
force exercifes a greater a(5lion according as the
bodies are more divided, and as they mtuually
touch each other in a greater number of points.

The molecule of bodies which touch us in a
flate of great divifion tend with greater or lets
force to combine with our parts ; and this combi-
nation is always a fort of alteration or deftrudlion,
which the organization makes an effort to refifti
This effort is exercifed by an increafed a6lion of
the different organs ; fo that every fubfi:ance which
tends to combirie with our parts, begins by fli-
mulating them with more or lefs force,

18. It is neceffary that our organs fhould habi-
tually retain that temperature amidfl which they
were developed.

The organs, in a great meafure, are formed of
tiffues of veflels, and the fum of the capillary vef-
fels is much more confiderable than that of the
large veilels.

If the fluids contained in all thefe veffels fol-
low^ed the different degrees of the temperature
of the atmofphere, very confiderable changes

would

SENSATIONS. . Q,05

would take place in the whole organization, by
their ereater or lefs condenfation and rarefaftion ;
and all thefe aqueous or adipofe fluids would
freeze at a temperature below zero, and would
melt or be evaporated at the ufual temperature of
warm countries.

Butj every organized being has the faculty of
maintaining itfelf at the temperature proper for
it 5 and when it is overcome by excefs of heat, or
the violence of cold, it dies before its fluids ac-
quire the temperature of the atmofphere. Hun-
ter found this faculty even in vegetables.

Man can endure changes of temperature much
better perhaps than animals: he is found in the
mofl different climates ; under the torrid zone,
and on the borders of the frozen ocean. During
long voyages, the fame men have experienced a
variation in temperature of more than loo de-
grees, during which the blood remains between
38 and 40° (100 and 104" Fabren.)

We are acquainted with no degree of tempe-
rature under which man may not exift. The
enormous degree of heat which Dr. Fordyce was
gradually able to fupport is well known ; and we
know, on the other hand, what extreme cold the
natives of our climates have withftood, during:
the very fevere winters in Canada, Siberia, Nova
Zembla, and Spitzbergen. It appears, that with
good clothing, abundance of food, vinous and
5 alko-

2G6 vital FUNCTIONPS.

alkobolized liquors, but in particular proper ex*
ercife, man in all climates may retain his habitual
temperament.

19. The organization affords different means
for refifling cold and for fupporting heat.

When a man is expofed to a low tempera-
ture, the atmofphere draws off from him his
caloric, and this lofs of heat reduces him to a
fiate of uneafinefs, which excites him to motion.
If he obeys this impulfe, he walks or labours
with energy ; his refpiration and circulation are
Jncreafed ; he has a greater appetite ; digeftion is
fpeedier, and the difengagement of heat, which
refults from thefe different fun 6f ions, is much
more confiderable. On the other hand, the ac-
tion of cold tends to thicken the texture of the
Ikin ; cutaneous perfpiration is diminifhed, and
the lofs of heat occafioned by its evaporation is
much lefs.

But, if the abflradlion of heat, effe6led by the
atmofpheric air, be conliderably increafed, and if
the vital a6fion is not fufHciently powerful to de-
velop caloric, in proportion to the lofs of it which
is occafioned, the individual is gradually weak-
ened and exhaufled by the efforts of long re-
a6tion, and falls^into a ilate of deep, which, un-
lefs he receives fpeedy afliflance, foon becomes
fatal. ' .

la

SEItfSATIONS. 207

In the moft northern climates, the favages go
out to hunt during the fevereft cold ; and of thofe
who are threatened with a flow and painful death,
forne know that they can die in an eafier manner,
by remaining expofed to the cold in a ftate of
perfe<9: reft.

Of the Dutch failors^ who wintered at Spitz-
bergen, the greater part of thofe who remained
fhut up in thdr wooden hut perifhed j while thofe
who went out into the open air, and who em-
ployed themfelves in hunting and other exercifes,
furvived.and fuffered very little inconvenience.

20. On the other hand, when a man is ex-
pofed to a very high tefinperature, he experiences
an uneafinefs of another kind : refpiration, in con*
fequence of inhaling air very much rarefied, is
rendered more difficult and lefs energetic j he ex-
periences a tendency to repofe ; his appetite de-
creafes ; he eats little and drinks more ; the fkin,
dire6lly flimulated by the contadl of the warm air,
becomes relaxed ; a fecretion of fweat takes place
in greater abundance ; the evaporation produced
at the furface of the body carries with it a great
quantity of heat; and the individual is thus
maintained at his ufual temperature : but if the
heat of the air continues or increafes, in an ex-
celfive proportion, he neceffarily finks under it,
and becomes exhaufl:ed, not only by the employ-
8 ment'

2(>g VITAL FUNCTIONS.

ment of the force neceflary to free him from the
excefs of the heat, but alfo by the real lofs of
the juices carried off by an abundant perfpiration.

To whatever natural temperature, therefore, a
man may be expofed, the heat of his blood, when
in a fliate of health, always remains at 38 or 40
degrees of the centigrade thermometer (104° of
iFahren.)

Every time that the atmofpheric air takes from
him, or fupplies him with caloric in excefs, the
whole of the organization makes an effort to re-
turn to and maintain itfelf at the habitual tempe-
rature. In either cafe, the vital power is at firil
exalted ; and it may be faid that the abdraftion
or addition of a certain quantity of heat is always
in the commencement a ftimulant to the organi-
zation.

When the ftimul:.::n,^ a61ion of the heat or
cold is too violent, or continues too long, it
waRes the flrength and leaves the body in a
ftate of feeblenefs or exhaufiion more or lefs
ftriking.

When a body ftrongly heated is applied to any
organ, a great part of the heat communicated to
it fuddenly deftroys its texture j the reft is con-
veyed to a greater depth, and a61s as a very ac-
tive irritant. The impreffion received is tranf-
miited by the nerves to the brain ; this organ in-
ilantly reads on the afFefted part, as well as on

the

SENSATIONS. 20^

the whole, of the organization, and produces that
mode of adion which conftitutes the fenfation of
pain.

When aduftion takes place in a paKied limb,
the impreffioii is not tranfmitted^ becaufe the
nerves of the organic life are deftroyed, and the
fenfation of pain does not enfue ; but the other
phaenomena are the-fame, though flower in their
progrefs, and take place by means of the nerves
which accompany the veflels.

When a part is inftantaneoufly diforganized by
a very great degree of heat, fuch as the applica-
tion of a piece of iron brought to a white heat, the
fenfation is duller and lefs painful : it fometimes
happens that a patient, when a nerve has been
deftroyed in this manner, thinks he experienced
a very intenfe degree of cold.

When a part has been diforganized by heat,
thofe in the neighbourhood enter into a new mode
of adlion. (See Phlegmafia.) The dead part de-
taches itfelf ; and there remains an excoriation or
a wound, which cicatrifcs in the ufual manner.

ai. Light exercifes a very liriking a£^ion oti
organized beings. Every living body, when ex- _
pofed to light, expands in a vigorous manner, and
afllimes a darker tint; the colour, fmell, and
tafte of the different produces of fecretion have a
more ftriking charader : while beings which grow

VOL. in. P up

2,10 VITAL FUNCTION'S.

up in the (hade remain pale, ftunted, and aque-
ous, and exhibit all the iyrnptoms of feeble and
languilning life.

The long continued acTtion of light and heat
on the human fldn, in the mod loulhern coun-
tries, renders it brown, and caufes its mucous
membrane to affume a black colour. This colo-
ration may have been heightened and propagated
by generation, and may thus have produced, a
variation in the human fpecies.

2 2. The eleclric fluid, univerfally diffufed
throughout the atmofphere, feems to have a great
influence on the organization. Every perfon may
have obferved, during ftormy weather, efpecially
when the atmofphere is damp and warm, that the
body fometimes feems to be opprefied, without
force and without energy, and that the limbs are
as if exhaufled with fatigue. This difpolition does
not correfpond exactly with the fiate of the ther-
mometer and of the hygrometer ; but it might
perhaps be marked by a proper ele61rometer. It
would appear, that in this cafe the damp air,
which is a very good conda(51or of the ele<Elric
fluid, draws off that fluid from living bodies,
and on this account they remain enervated and
wirhout reaction.

23. Every organized body^, which is continii-

5 a'Jy

SENSATIONS. 211

ally Immerfed in an atmofphere latarated with
water in a ftate of vapour, becomes pale, relaxed,
and without energy *. This is the cafe with forne
fpecies of animals, fuch as fheep ; with vege-
tab1'-\ in general ; and in particular with herba-
ceous plants.

34. Independently of fubftances univerfally
diffufed throughout the atmofphere, to the influ-
ence of which man is continually fubjedled, there
are a great many others, with which he is inti-
mately conneded by nutrition, by his artificial
w^ants, and by his health ; or with which he is ac-
cidentally brought into contadl. All thefe fnb-
flances exercife on the organization an action, a
careful cbfervation of which is of fome import-
ance.

When foreic:n fubflances are in immediate
conta6l with our organs, the following phseno-
mena are, in general, obferved :

ill. Thefe fubuances tend to combine with the
living body in the ratio of their chemical afnnity;
and thus make an effort to defi:roy the organic
ftrufture of the part to which they are applied.

* The afFedlion produced by the long coiitinued Influence of
dampnefs, added to want of food, or to food of a bad quality,
is diftinguifhed in man by the name of the fcurvy ; in fiieep and
plants it is called the roi j in fwine the hfrofy^ &c«

p 2 ad.

212 VITAL FUNCTIONS.

2d. On the other hand, the living organs
tend to decompofe or to digeji thefe fubflances,
and to reduce them to a ftate which renders
them fufceptible of entering into the circulation,
and of thus ferving to repair the nutritive fluids.
The organs alfo make a continual effort to expel
all thofe fubflances which are improper for nutri-
tion.

3d. In the laft place, the foreign fubflances, by
their contad: with the organs, produce an imprel-
lion which may be tranfmitted by the nerves to
the brain ; and the refult is a change in the ge-
neral flate, which zoxv^\i\x\&'ifenfation.

When a foreign fubftance tends to unite itfelf
to the organic parts, with a force greater than
that with which the organs are endowed to re-
flft, the refult is a real chemical combination.
This combination does not completely take
place, except when the nerves of the part have
been entirely diforganized ; but if vitality ilill
cxercifes an a6lion, this chemical phacnomenon is
more or lefs modified.

When the foreign body, applied to an organ,
poffeffes a great force of affinity, the phaeno-
menon has a perfe6l refemblance to that which
refults from the a6iion of heat : the nerves are
fpeedily deflroyed, and the chemical combination
is then efle^ted to faturation. Such is the a6lion of
cauftic alkalies, of alkaline earths, of concentrated

mineral

SENSATIONS. 213

mineral acids, of feme oxides, and of feveral
faline fubftances.

Thefe different fubflances are employed in far-
gery to defiiroy difeafed parts, or to open caute-
ries. Thus a bit of caufiiic pot-aflT, applied to a
portion of tfee fkin, has a ftrong tendency to
attract all its humidity ; and the organ is foon
dried up and deftroyed. The alkaline fubftance
then combines with the fat fubflances, and the
refult is a fort of foap ; the living parts in the
neighbourhood of the fear, and which have been
irritated, enter into a new aclion ; the fear de-
taches itfelf, and a common wound remains.

Thefe different mineral fubftances, introduced
into the alimentary pafTages, deftroy in like man-
ner the parts with which they come into contad,
and produce accidents which often prove mortal.
In fuch cafes the wound made in the gaflric or-
gans, and the fubfequent accidents to which it
gives rife, are an evident caufe of the perfon's death.
Thefe phenomena are altogether different from
thofe obferved in cafes of poiloning j after whicji
no trace of alteration is obferved in the parts which
received the poifon.

When the vital power offers a partial refinance to
the chemical action the phsenomenon is modified.
Thus, in a man whofe organization is confider-
ably weakened, a limb affected by a wound, or
exhauHed by long fuppuration, prefents but a

p 3 feeble

214 VITAi:. FUNCTIONS.

feeble refiftance to ihc force of chemical affinity.
The gangrene which, in fome cafes, enfues is the
refult of the chennical adion of heat, of moiaure,
and of atmofpheric air, on the hmb half dead,
which indeed exhibits all the 'phenomena of pu~
trefadion, raoditied by a remainder of life.

In the laft place, if the foreign body exercifcs
only a very feeble adlion on the organs, it may
remain in contacl with them, and yet produce
no accident. Thus, a mulket ball remains with-
out any inconvenience amidft parts, the aftion of
which it neither confines nor impedes.

2,5. When the fubflances brought into contaft
with the organs are fafceptible of an eafv decom-
poiition, as is the cafe with all thofe which arife
from organized bodies, or which form a part of
them, they are then digeited by thefe organs, and
reduced to fimpler compounds, fufceptible of be-
ing taken up by the abforbing veilels, and con-
veyed into the torrent of the circulation to form
part of the nutritive fluid : the relidue is thrown
out by different paflages.

Thefe fubftances are digeflied not only at the
furface of the alimentary paiTages, but alfo by all
the organs. Thus the produ6l of the fccretions
depofited in the fplanchnic and articular cavities,
the purulent colle6iions, fmguinolent efFufions,
lumefaflions^ concretions^ and urinary or bilious

calculi^

SENSATIONS. 215

calcuHi may be digejled\ and being then reduced
to their iirft principles they enter into the circa-
iation.

The digeftive power of the different parts does
not depend on the diflblving action of the animal
fluids. This diftipd a6lion is exceedingly weak,
even in the digeflive juices. But thefe fubftances
are digefted by a force peculiar to vitality, and
which has no relemblance to chemical affinity.

If ofleous concretions, calculous tophi, "and the
different kinds of calculi, are evidently digefted
by the a6liou of the organs, under certain circum-
ftances, there can be no doubt that the various
liquids effufed are alfo digelled before they enter
into circulation. It is, indeed, hardly to be be-
lieved, that the pus, urine, bile, &c. are taken
up without alteration by the abforbing veffels, and
thus conveyed into the blood. Befides, this hy-
pothefis is deflroyed by the ingenious experiments
of Dupuytren. This anatomifi: afcertained that
the injedion of thefe fubflances into the veins
always produces accidents more or lefs dangerous,
and very often fudden death. It may alfo be
added, that chemifts have never found in the
blood any of thofe foreign fubftances, which were
fuppofed to be fufceptible of pafiing into it with.
fo much facility.

When a foreign body, depofited in an organ,
cannot be digefted in it, and if it form an incon-

p 4 venient

2l6 VITAL FUNCTIONS.

venient ftimulant, it gives rife to the development
of a phlegmon, which fuppurates ; and the fo-
reign body is then thrown out by the aperture
along with the pus.

That the organs may be able to exercife on
the different foreign fubftances that force which
is neceflary to digefl; or to expel them, they muft
enter into a new mode of a6:ion. This change of
ftate in the organs is produced by the prefence of
the.foreign body, and by the impreffion of contadl
which it exercifes on the nerves of the part with
which it is in relation.

a5. After birth, the firfl: fenfations which the
organs experience are q\w ays pa hrful ; and children
give external figns of them by cries : they either
cry or feem indifferent. But the organs, by
their gradual expanfion, acquire improvement,
and the individual is at length able to appreciate
a change of ftatc which takes place in any part,
though it be very trifling, and though it does not
interrupt the natural order.

When this change of ftate tends to facilitate
the execution of the different fun6lions, and thus
contributes to the completion of life, \.h& fenfation
is agreeable.

The rea^lion, casteris paribus, of the centre of
the nerves, when an impreflion is received, is di-
recled in particular to the part which has been

touched ;

SENSATIONS. 2 If

touched ; and if this part has experienced an al-
teration in its organic ftrudlure, the impreffion is
continued, and always produces a painful fenfa-
tion.

The impreffion made on an organ is the more
lively, as the nerves are more immediately ex-
pofed to the contacl of the foreign bodies, and
as their pulpy part prefents a greater development
at its termination.

The fe.nfation which refults from the impref-
fion made on an organ is the ftropger, as its
nerves proceed more dire61Iy to the centre of the
cerebral organ (the brain). Under this point of
view, the parts .leafi: proper for producing fenfa-
tions are thofe, the nerves of which proceed to
the trilplancbnio ; and thofe mod conveniently
difpofed for producing lively and fpeedy fenfa-
tions are the fyllems of organic life, and even
thofe of relative Hfe, or the organs of the fenfes,
the nerves of which terminate directly at the en-
cephalon. .

A flight impreffion made on any part, the nerves
of which correfpond with the trifplanchnic, pro-
duces a change of ftate more or lefs ftriking, but
does not occafion any fenfation. When this
change of ftate is continued or increafed, and
if it , deranges the natural order of the organic
fyllem^ of which it forms a part, the derangement
becomes a new impreffion. This impreffion is

propagated

218 VITAL FUNCTIONS.

propagated by the nerves of the organic fydem
as far as the cerebral centre, the reaction of which
on this fyflem confiitutes lenfation.

Thus, the impreffion made on the macous
membrane of the genito-iirinary pafri5ges, by the
conta6l of the fecretion of a blenorrhagia, or on
that of the aerian paf!ages, by the contadl of cold,
damp air, produces very often no fenfation. A
very ftriking new^ mode of adlion, however, is
developed in thefe parts, the membranes of which
fwell up and fecrete a new produ61. Thefe
changes foon become a new impreffion, and the
refult is a painful fenfation, which takes iplace in
confequence of a derangement in the fundions of
the genito-urinary and the relpiratory organs.

After an imprefHon made on a point of the
vifcera of the abdomen, there often takes place
a new mode of aftion, which gradually increafes,
v.'ith an alteration in the organic fi:ru(5iure of the
part, but without producing Jen/a/ ion. Thefe dif-
orders are not felt except when of contidcrable
extent, and when they produce flriking derange-
ments in the funcflion of the fyftem of digeftion.
This is what takes place in all the flow phlegma-
lise, commonly called ohJlruBlons.

27. A foreign body, to produce a new mode of
a'5lion in the whole organization, does not need
to be abforbedj and to be conveyed to all the

parts^

SENSATIONS. 219

parts, to occaiion in them the different diforders
which refult from its prefence. Nothing is ne-
ceflary but that there (hould be an impreffion by
contaft on' the nerve^ and that this impreiiion
fhould be tranfmitted to tlie nervous centre.

All the inllances quoted, in fiipport of the opi-
nion that morbiiic fubfiances are abforbed, only
prove that they may be fo, but do not prove that
they really are Cibforbcd; while, in many cafes, it
is evident that nothing is abforbed, and yet the
fame effects have been produced. Thus, when
the variolous npatter has been introduced below
the epidermis of the hand, there come on, in the
courfe of a few dajs, rednefs, pain, heat, and
Iweliing in the part which has been pun(5iured j
the pain is continued along the arm, with a red-
difh ftreak, which feems to mark the progrefs of
the virus ; and a fwelhng takes place in the glands
of the arm-pit. At the end of fome days the
individual experiences a pain in. the head, fever,
and a general derangement, which feems to indi-
cate that the i^ifedtion has been univerfal, and that
the virus has been conveyed, as is faid^ into the
whole mafs of the blood.

But an evident proof that this progrefs of the
virus is not neceffiiry for the production of all
this feries of phaenoraena is, that the lame fym-
ptoms are exhibited when a thorn is introduced
into the finger, though it is very certain, in this

cafe,

^20 TITAL FUNCTIONS.

cafe, that the thorn has not been abforbed. The
prefence of the thorn, under the epidermis, is not
even necelTary to occafion all thele accidents ;
they might be produced by the prick alone. Thus
a woman, whofe fingers are very clean, pricks
berfelf with a needle, which is alfo very clean ;
and the confequence fometimes is the fame feries
of phsenomena. Nothing indeed is neceffiiry but
the picky it is it alone which produces all thefe
accidents.

It is well known that many perfons expe-
rience violent colics, and are attacked by diar-
rhoea, when expofed to cold in the feet, la
this cafe, the impreffion of the cold reprefents the
prick ; and ftill an effedl is produced on a diftant
part, though nothing has been ablbrbe^'.

After a blow or a fall, &c. there often come
on fevere diforders in organs very far diftant
from thofe which have been injured.

Hence it is evident^ that the ablbrption of fo-
reign fubftances, virus, &c. and the conveyance
of them into the blood, to produce different dif-
eafes, is an hypothelis fupported by no certain
proofs ; which is contrary to the general laws of
organization, and which, inftead of throwing light
on thefe fadts, tends rather to obfcure them.
The continual application of fo great an error in
the treatment of difeafes cannot fail of being
often dangerous.

The

SENSATIONS. 321

The Impreffion of certain foreign bodies is of
fach a nature, that the rea6lIon is always effected
on the fame organ, whatever be the part where
they have been apphed. Thus cantharides al-
ways produce a rea£lion on the genito-urinary
or2:ans : fubftances of this kind are faid to have a
Jpecific a6fion.
' Some fubftances caufe an increafe of general
ac^lion, without producing derangement in any
organ in particular, as is the cafe with opiumi and
alcoholic beverages. When this intoxicating ac-
tion has been long continued, or powerfully excited,
the organs experience great weaknefs, and the
exhausted individuals tumble down or fall afleep.

la the lafl: place, fo'Vne fubftances occafion a
fudden derangement, or a general diforder, which
produces inftant death, after a few convulfions,
without leaving any traces of alteration in the
part which received the impreffion. Of this kind
are thofe poifons called narcotic, the afphyxiating
gafes, and the poifons of feme animals.

a8. Thefe obfervations on the phsenomena of life
give rife to feveral important confiderations, which
ought always to be kept in view.

Thus, the refult of every impreffion made on
a part provided with nerves, is a change of ftate,
or new mode of adlion, in one or more organs, or
in the whole of the organization.

7 Con-

222 VITAL FUNCTIONS..

Confcioufnefs of a chonse of (iaie, which has
fuddenly taken place in the whole of the organi-
zation^ conftitntes fc-nfation.

The irnpreiiion made on the organs v/hich re-
ceive their nerves only from the trifplanchnic,
occalions in thcfe parts a How aheration, which
very often produces no dlrcLl j'ciifalion.

The aheration of thefe organs may then be-
come the caufe of fenfation, when it is llrong
enough to didorb the organic fyiiera of which it
forms a part.

The changes which take place fuddenly in thofe
lyfiems of organs, the nerves of which proceed
dire611y to the encephalonj or to its prolongatioB,
slways produce fenfations.

The fenfations are painful when the new mode
of adlion tends to difturb the jnatural order of
the functions ; and they are agreeable when it
contributes to caafe them to' be performed witb
more force and energy.

ORGANS

[ 223 ]

ORGANS OF THE SENSES.

29. The organs of tlie fenles almoil all receive
their nerves from the encepbalorij by a very fhurt
paflage. Thefe nerves exhibit, at their termina-
tion, a peculiar ftrudlure, which renders them fit
for receiving the impreffion of every thing
around them, or which ftrikes them. By this dif-
poiition, the organs of the fenfes bring man into
relation with every thing without him, by making
him experience very nrong fen^ations. The func-
tion of thefe organs will be the fabject of the fol-
lowing obfervations.

30. Touching, The fenfe of touching rciides
in the pulpy termination of the nerves of the Ikin.

The cutaneous lyflem is compofed of the dermis

and the epidermis. The dermis, or fldn properly

fo called (cor'mm), is a thick membrane, of a clofe

and elaftic texture. The numerous nerves which

proceed thither traverfe this m.embrane, and tbrm

at its furface a pulpy expaniion difficult to be

obferved. This nervous termination is accom-

. panied by a reticular tifTue of fanguiferous vetTels,

exceedingly fine, and the whole is covered by a

mucous ftratum or coating, in which the colour of

the fliin refides.

The

f2'l VITAL FrrNCTlONS.

The epidermis is a thin dry pellicle, which
feems to be inorganic : it appears to be formed by
the jundion of fmall imbricated laminae.

The difpofition of the cutaneous fyftem is ex-
ceedingly well calculated to maintain the nerves
of touching in a proper ftate of moiflure and pli-
ability. The epidermis ferves to fecure thefe
nerves from the immediate contact of external
bodies.

The whole furface of the body poflefles the
tadlile faculty, and may receive the impreflion re-~
fulting from the mafs, from the volume, and even
from the figure of the refilling bodies, as well as
from their thermometric and hygrometric ftate ;
but it is chiefly by means of the hand, and by long
and continued exercife, that man is enabled to
appreciate properly thefe pbyfical qualities of
bodies.

The admirable difpofition of this organ allows
it to yield to \heir figures j to touch them in all
their points ; to pafs over their whole furface with
great facility ; to lay hold of them, to prefs
them, and to raife them up ; and thus to bring
itfelf into relation with them in the moft intimate _
manner.

The hand of man, which may be exclufively
employed in the contadl of bodies, is fufceptible of
acquiring, by long habit, an inconceivable degree
of perfedion and of delicacy, as has been obferved

in

ORGA'NS OP THE SENSES. 225

In fome blind perfons, who by the touch could
diftinguifh even colours.

The hand, confidered as an organ not employed
for^walking, is an attribute peculiar to the human
fpccies; and it has juftly been confidered as the
principal inftrument of his fuperiority over ani-
mals.

ThQ organ of touching is that alone which
brings us into immediate relation with the whole
of the furrounding bodies. The other organs of
the fenfes only receive the impreffion of conta6i,
which refults from fome of their particular proper-
ties. Thefe organs can be improved and become
ufeful to us, only io far as Ihey begin to be exer-
eifed in concurrence with the organ of touching.

31. Taji'ing, The fenfe of tafting is only a
more;exqui{ite organ of touching, exercifed by the
membrane which envelops the mufcular body of
the tongue, and by that which covers the infide of
the mouth.

Thefe parts have the faculty of perceiving the
impreffion made on them by fome particular fub-
fianccs, and efpecially by thofe fulceptible of af-
fuming the grcatefi: degree of divifibility, by dif-
folving in the faliva.

It is chiefly the upper part of the tongue, and
the lips, that poflefs the faculty of tailing in the
higheft degree ; bccaufe they are the firft which

VOL. II f. Q^ prcfent

prefent themfelves ta receive the favoury Tub*
ilances, and becaufe^ tbey are more habitually exi
ercifed in that operation.

The part of the tongue, on which the fenfe of
tafting is more particularly exercifed, exhibits a
peculiar ftrufbure ; it is covered with papillae of
different forms and fizes, which, when in con-
ta6l with fapid bodiesj enter into a kind of erec^
lion.

32. Smelling. The organ of fmelling is com-
pofcd of the membrane that covers the interior
part of the noftrils.

This membrane has the property of receiving
the impreffion, made on it by the contact of cer-
tain molecule of matter, in a ilate of great te-
nuity.

Before a fubiiance can afFe^i: the olfaiclory mem-
brane, it muft be in the ftate of gas, or fufficiently
divided to keep itfelf in folution or in fufpenfion
in-an aeriform fuhftance. FJence it may be feen,
that all bodies are fufceptibleof ailuming that ftate
which i« proper for affecting the organ of fmell ;
and that all fubflances,. very much divided, may
become odorous bodies.

; Bodies are not odorous in confequence of any-
peculiar property inherent in their nature, but
only by the common faculty of affecting the organ
©f fmell ; foihai certain bodies are odorous \X> one

-■ ^ and

ORGANS OP THE SEK9ES. 22/

and not to another. A great number of fub-
Itances are odorous to the dog and the Twine ; but
are not Co to man.

r Though, in general, a very fraall number of
fubftances only are odorous, the greater part of
bodies afFedl the fenfe of fmelling, when in a ftate
of extreme divifion, and conveyed to the oI'a(5tory
nerve in fufficient quantity and for a certain time.
It even appears that to fome animals, fuch as dogsj
every body whatever is odorous. The power of
fmelling appears, in general, to be in the ratio of
the extent of the nafal fofTae.
• When fubftances produce analogous tenfation?
in the olfactory organ, they are faid to have the
fame odour; and fubftances which exhibit very
little phyfical, chemical, or organic relation, very
often afFeiSl the olfadlory organ in the fame man-
ner; Co that it is difficult to determine whether
the impreffion produced on the olfacSlory mem-
brane, by the moleculae of the odorous bodies, de-
pends on the form of thefe moleculee, or on their
chemical compofition.

The azotic and oxygen gas of which the atmo-
fphere is effentially compofed, and which are in
continual contadl with the olfadlory membrane,
make no impreiTion upon it ; but thefe gafes ferve
as an excipient to odorous fubftances, which they
hold in folution or in fufpenfion.

Atmofpheric air conveys odorous, fubftances, to.
Q^a the

'lis ■ -iriTAL FUNCTIONS.

the noflrils, while it pafles through them to pro-
ceed to the lungs duriiig refpiration; fo that thofe
defirous of fmelling with more force, muft fhut
the mouth and make a ftrong infpiration through
the noftrils.

The odorous moleculas, thus depolited on the
olfa61ory organ, make en it an impreffion of con-
ta61, which is propagated as far as the brain, and
determines that organ to produce a movement of
Efcneral and inftantaneous readiion, which confii-
tutes the fenlation of fmell. This movement of
reaQion is fomctimes fo violent that, in fome wo-
men of exceffive fenfibility, it occafions vertigo or
fyncope.

The organ of fmell, like all the other organs, is
flrengthened by exercife, and is weakened by too
fbrong or too frequent adiion.
' A man who is habitually in the midft of certain
odours, • even exceedingly ftrong, becomes at
length infenfible to their aclion ; but he who is
frequently in relation with odorous bodies of a
different nature, and who continually Iludies their
a6iion, may acquire the faculty of fmelling in an
emJnent degree, and perceive odours exceedingly
volatile.

The membrane which lines the finufes is thin
and fmooth ; and' its ft ru61ure has no refemblance
to that which lines the natal fotiee : it is therefore
probable that it does not lerve for perceiving

odours.

ORGANS OF THE SENSES. Q.IQ

odours. The ufe of the finuffes feems to be, to re-
tain a larger quantity of air.

33. Seeing, The vifual fyftem confiUs efTcn-
tially of a very thin membrane, which lines the
bottom of the eye, and which has the property of
perceiving the imprefiion made on it by the con-
tadl of the light, either direct or rcfleded, from
external bodies, and refracted on it by the tranf-
parent fluids of the eye.

The eye is compofed of three tranfparent bodies
of different denflties, placed one within the other j
and each contained in a thin pclhcle, which per-?
ceives the conta6l of the lighl,

This apparatus is enclofed in a double covering;,
thick and blackifh in the infide, having in the fore-
part a contra6iile aperture, before which is placed
a cartilaginous and tranfparent fegment of a
fphere,

This dioptric arrangement has fome refemblance
to that of an achromatic telefcope, or of a camera
obfcura. It feems to have acquired all its develop-
ment at the period of birth.

In the fundlion ot the vifual organ, if the lumi-
nous rays which proceed diredtly from the fun
reach the eye, a bundle of them, equal in fize to
the aperture of the pupil, penetrates into it. This
|:mndle is refraded by the humours of the eye;

<^3 i^nd

230 TITALrUNCTiONS.

and the parallel rays, which compofe it, approach-
ing each other, from the perpendicular diredion,
converge on the retina.

The contac^l of this luminous point produces,
on the retina, a ftrong impi^effion, which is propa-
gated to the brain, and occations a fudden and in-
Hantaneous change of ftate. This change of Hate
excites in the eye a movement of rea61ion ; the
iris expands, the aperture of the pupil is contra<5l-
ed, and the eye-lids approach each other. Thefc
parts oppofe, in this manner, the introduction of
the luminous rays, the impreffion of which pro-
duces a painful and vague fenfation.

The luminous rays which fall on bodies are re-
flected from every part of them in a diverging
form, and the angle of their refie6iion is equal to
that of their incidience.

To have a proper idea of the aSi of vifion, we
mufl fuppofe that a cone of light proceeds from
each point of an illuminated body, and that all
thefe luminous cones are propagated, in a diverg-
ing form, without being confounded.

The light proceeding from a body which falls
on the apefture of the pupil, is compofed of por-
tions of all thefe luminous cones, which have their
fummits in different points of the illuminated
body. But the whole of thefe portions of lumi-
nous cones form another inverted cone^ the bafe

of

ORGatNS -OP TrHB -SENSES. ,^3 J

jof which Is meafurcd by the fize cf the. bady, aad
its truncated fummit is equal to the aperture of
the pupil.

To conceive the progrefs of reflected and re-
fra(5ied light on the retina, it will be proper to fol-
low the courfc of a luminoLis cone, procfeeding
from one lingle point of a body ; and what has
been faid of this cone of light may afterwards be
applied to tKofe which proceed from all the other
illuminated points.

A luminous cone^, which proceeds, from any
point of an illuminated objec?!, reaches the eye in
a diverging form. The rays of this cone, which
fall upon the tranfparent cornea^ pafs through it,
and are refradled from tlie perpendicular dirediou,
in the ratio of the denlity and convexity of that
cartilage. Thefe rays continue to be refradled in
pafling through the aqueous humour, and reach
the iris, which affords a paflagc to a quantity..of
light, meafured by the aperture of the pupil: the
reft are refle6ied. The rays of the luminous cone,
which pafs through the aperture of the pupil, foon
reach the lens of the cryftalline humour, ^nd are
more ftrongly refraded in the ratio of its convexi-
ty and of its denfity, which is greater than that of
the other humours. Thefe rays afterwards pafs
through the vitreous humour, and experience a
third mode of refradlion, in the ratio of the denlity
of the vitreous body. Thi's rcfradiion then is

0^4 weaker

0,31 VITAL FUNCTIONS.

weaker than that produced by the cryftalHne hu-
mour, but ftronger than that occafioned by the
aqueous : fo that the luminous rays, in pafiing
through the three tranfparent bodies of the eye,
are differently refracled, in a fort of zig-zag form.
By thcfe means, the rays which in traverfing the
aqueous humour began to be decompofed and to
be feparated, as in the prifm, are again confounded
or mixed in paffing through the cryllalline hu-
mour; and the decompoiition produced by the
cryftalhne is dcftroyed by the vitreous humour.
In confequence of this arrangement, the rays tra-
verfc the eye without experiencing any alteration,
retain all their purity, and are never tinged with
the prifmatic colours.

To avoid coloration with the prifmatic colours
in telefcopes, feveral glaiies of different denfities
are applied to each other; and this difpolition,
analogous to that of the eye, is diilinguiOied by
the nameof^r^^'/^row^^'i^.

In the lall place, all the rays of the luminous
cone, continuing to be refradiied through the vi-
treous body, unite in one point, which iirikes the
retina; and it may therefore be faid that the light,
which proceeds from an illuminated point of any
objc6l:, proceeds to the retina, forming two cones
oppofed to each other by their bafes.

What has been here faid, in regard to the pro-
grefs of this cone, proceeding from one illumi-
nated

ORGANS OP THi5 SENSES, ^33

liated point of an object, may be applied to thofc
which proceed from all the other illuminated
points of that body, and which alfo proceed to the'
eye. All thefe cones of light traverfe the eye in
different direfllons, crofs each other without being;
confounded, and converge on different points of
the retina, preferving the fame refpe<5tive polition,-
which they had when they proceeded from the
illuminated objed. All thefe luminous points de-
fcribe, in this manner, the image of the objedl oil
a fmall fpace of the retina, producing on that
nervous membrane an impreffion, more or leis
lively, and of greater or lefs extent. The rays
which fall in a dire6lion perpendicular to the axis
of the eye, are propagated in a (Iraight line, and
experience no refraction.

The rays which diverge and fall on the choroid,
are abforbed by ihe black coating of that mqm-»
brane.

As the luminous cone, which proceeds from
each point of an illuminated objefl, converges on
the retina in the direction of its axis, it mufl occu-
py on that membrane a pofition, the reverfe of
that which it had in the obje6l, and the image is
confequently inverted j but to fee obje6ls in the
diredion of the axis of the luminous cones pro-
ceeding from them, is the difpofition proper for
making them appear to us upright. Befides, we

hav«

334 TITAL FUNCTIONS.

have not the faculty of perceiving the top or th^
bottom, the right or the left, of our retina.
. When the light which falls on the furfacfe of a
body is refleded entirely, it produces a deter-
minate impreffion (white) ; but the impreffioq
changes when the body decompofes the light,
abforbs one part of its rays, and refle6ls the other.
. Light is decompofed into feven rays, which,
being refledled in all the combinations poffible to
|brm the di^rent images, produce on the retina
an indefinite feries of particular impreOlons.
; Of the points which refled the light, thofe
which abforb it entirely produce a negative fenfa-
tion (black).

, It is not as an image painted on the retina th^t vi^e
have a fenfation of obje6^s ; for this image would
be of no utility. Another eye would be neceflary
to look at it. But it is becaufe the luminous rays,
in delineating that image, produce on the retina
an impreffion of contadl, more or lefs lively, and
of greater or lefs extent.

. The imprefiion made on the retina, by the con-
tact of the light receded from objeds, produces
at firft a very uncertain fenfation: it announces
.that the bodies exifi and are different^ tince they
produce variable impreffions; but thefe impreffions
give no idea of th^ form, fize, or diftance of thef
objeds.

. Though bodies of the fame form produce fimi-

lar

ORGANS OF THE SENSES. ^35

tar fen rations, the impreflion produced by the re-
fiedion of the light could never have ferved for
determining thefe forms; and if men had not beeri
endowed with the faculty of touching, they could
nevei' have been able to tell whether bodies vverds
round or fquare, according to the ideas which we
affix to thefe words: they would only have faid, the
Jx)dies, the refledted light of which produces the
ienfations A B.

A perfon born blind, when cured by couching
for the cataract, does not all at once enjoy the fa-
culty of feeing the light. When fhown the cat
which he has been accuftomed to carefs, he does
not know what it is. When made to touch it, he
immediately exclaims, " it is my cat, I fhail no
longer require the aid of touching to diflinguiili
it." But this contact is abfolutely neceiTary, and
he might continue to touch it without feeing it,
and to view it without touching it, and confider it
as two different objects.

The imprdlion produced by the light refle6led
from any body cannot enable a perfon to judge of
its dillance. The man born blind, who was re-
ftored to fight by Chefelden *, imagined that all
bodies fhown to him were in contadt with his eye ;
becaufe he had been accuftomed to receive imprel^
iions of touching by immediate contadt, and not
by the intervention of a refledled fiuid.

* Philofophical Tranfaftions for ijaS.

Since

S35 ' TITAL FUNCTIONS.

Since light refledled by a body cannot enable us
to judge of its diftance. rt can as little give us any
idea of its volume: the fize of bodies, indeed,
forms the fonrce ofthemofl frequent optic ill u-
lions which we experience, and which we often
cannot prevent, though we previoully know that
they will take place.

If an obje6t, completely detached from others,
be viewed through a hole, the perfon who looks at
it has no means to enable him to judge of its
magnitude and diftance. He, however, forms an
opinion of thefe two relations; and this opinion,
in regard to diftance, is alv/ays founded on the
manner in which the object is illuminated; and,
in regard to fize, on a comparifon of it with other
bodies the fize of which is known.

Bodies produce on the eye a flronger impref-
fion, according to the greater quantity of light re-,
ficfled from them. ( A fmall body, not much illu-
minated and fituated at a fmall diftance from the
eye, may be confounded with another of the fame
form, which fubtending the fame angle may be
firongly illuminated, of a very large fize, and
placed at a great diftance. Hence the eye alone
affords no means to enable us to form a judg-
ment of the diftance of an infulated body, placed in
infinite fpace, and with which we are unacquaint-
ed. It, however, cannot be faid that in all thefe
cafes the fenfe of fight leads us into an error, but

only

ORGANS OF THE SENSES. 23t

Only that it leaves us in uncertainty. This organ
cannot be improved and acquire the faculties pe-
culiar to it unlefs exercifed in conjun(Slion with
the organs of touching.

Were the eye merely a machine, there would be
only one point of fight out of which vilion would
ceafe ; but it is a living organ in all its parts,
which accommodates itfelf to a feries of diftances,
of greater or lefs extent ; which becomes longer or
Shorter ; renders the cornea flat or convex, pullies
it backwards or forwards, &c. ; and the bell eye is
that which pofleffes, in the higheft degree, the fa-
culty of varying its forms in fuch a manner, as
always to unite; in the fame point of the retina the
moft diverging rays, and thofe which approach
nearell to a flate of paralielifm.

When wc look very near at an illuminated ob-
je(9;, the iris extends and fends back the mofl di-
vergent rays. On the other hand, uhen we look
at a diflant object not much illuminated, tb.e iris
refumes its former flate ^ the pupil dilates, and re-
ceives a luminous cone much broader, but which is
compofed of rarer light and of rays more diver-
gent.

The quantity of light is diminifhed by propaga-
tion, in the dire6l ratio of the fquare of the di-
ilance.

Though we look with two organs we do noi {gq
two obje6b, becaufe the luminous rays falling on

both

aj3 VITAL FUNCTI0W3,

both the eyes in the fame diredlion, converge at
the fame time on both the retinas, and produce
two impreffions, perfe(9:ly fimilar, which are con-
founded. But, if th'fe difpofition be deranged ; if
the two eyes be not direded towards the objedl in
the fame axis ; if one be turned to one fide, or if a
perfdn voluntarily places them in a fquinting poli-
tion, obje6^s are feen double. In this cafe, it is
. obferved that one of the images feems always to be
more illuminated or nearer than the other, which
then produces two fenfations.

To render vifion diftin^t, the luminous cones re^
fracfted by the tranfparent fluids of the eye mufl:
reach the retina at the moment of their converg-
ing; for if they converge beyond or on this lide
of that membrane, the vifion is neceflarily con*
fuied. This precifion of convergency on the re-
tina is the refult of the degree of the convexity of
the cornea, of the refra61ing power of the hu-
raours of the eye, and of the diftance between the
cornea and the retina. When the natural proper^
tions do not exifi, and when the mobility of the eye
cannot refiore them, the point of fight is neceflirily
changed, as in the cafe of the myopes and pref^
•bytae.

The iifual point of fight enables a perfon tt^^'
read middle fized print difi.inclly at the diftanpi^-
of eight inches. ,

Objedls to be diftin6lly fcen mull be placed at

a diftance

ORGANS OP THE SENSES. 23^

a diflance proportioned to^heir lize: thus to fee a

painting, one mull remove from it to a diftance

double to its fize.

■ Some perfons, to fee diftin(5ily, do not'turn the

axes of both eyes towards the objed in an equal

manner ; this produces a deformity of fight called

fquinting. (Strabiftnus),

. For the moll part, one of the eyes only is not

direded towards : the objedl ; but Ibmetimes this is

the cafe with both. ■

Children, who begin to move their eyes about at
random, before they look at any thing with preci-
fion, or who look at objeds very near, cpntrad ^
habit of fquinting; but this deformity gradually
difappears. Strabifm may arife alfo from a weakr-
nefsoffomeof the mufcles, which produces am
irregularity of their adlion.

In this cafe, when it is not of long Handing, it
may be corre6led by placing on the eye which
fquints a conical tube, blackened in the infide,
and which ought to be gradually turned towards
that lide to which the eye can with difficulty be
dire<5led : this method mud be often employed and
for a long time.

Strabifm may be likewife occalioned by an al-
teration of fome parts of the eye. Perfons fquint
alfo inftantaneoully when they look at objedl^-
yery near, or with diftradion, or when they are in
an ecllafy.

Some
7

240 VITAL-FUNCTION'S.

Some perfons do nOt fee ol)je6ls di(lin6lly but
at a very fm all diftance. In this cafe, the eye ball,
for the moit part, is elongated and projecting, and
the cornea very convex. Perfons who exhibit this
difpolition are obliged to place the objects near to
their eyes ; but they have the advantage of poffelP-
Ing good fight and, of feeing diftindlly the fmalleft
obje^is. It may, indeed, be readily conceived that
the objedl being placed nearer to the eye, muft
fend out a more confiderable bundle of luminous
rays; and fince the eye receives thefe rays under
a greater angle, they are refracted with more difl
ficulty and are longer in uniting. This difpofition
is neceflary, becaufe the retina is further diftant
from the cornea, on account of the greater elon-
gation of the eye-ball, or of the greater convexity
of the cornea.

If the rays which fall upon a convex and elon-
gated cornea were more convergent, or aim oft
parallel, like thofe proceeding from diftant objefts,
they would be too foon refrafled ; their conver-
gency would take place before they reached the
retina, and villon would be indiflinct.

Shortnefs of fight, which varies from half a foot
to half an inch, is diilinguiflied by the name of
Myopia,

This affection exifis in all infants, and gradually
decreafes : fometimes it exifts till the period of
manhood, and is gradually corre<51ed by the de-

-preffion .

ORGANS Of TH£ SEKSES* 24l

preflion of the eye-ball, efpecially in perfons who
fatigue their eyes a. great deal, by continual occu-
pationn at a very faint h'gbt. Perfons very fhorU
lighted- appear, in general, to fquint, becaufe ihey
are obliged to incline to one fide in order that the
objedl may remain illuminated ;^4ind becaufe they
often look with one eye^ while the other rolls about
at random,

Short-fighted peopie acquire a habit of not
looking at thofe to whom they fpeak, becaufe they
can fee nothing in their face.

Old men often exhibit a difpoiition contrary to
that of myopia ; they do not fee objeds but at a
very great diftance; and their eyes aregenerally fiat*

Long fight, known by the name of -prefbyofia^
and which extends even to three {^tX, is always
very weak ; it feems to arife from a flattening of
the ball of the eye, which diminifhes the'power of
refrangibility.

As the eye has lefs refractive power, and as tha
retina is brought nearer to the cornea, by the flat-
tening of the eye-ball, the rays mufl neceffarily
be lefs divergent. Thefc rays then being nearly
parallel, are more eafily refradfed, and their conver-
gency being fpeedier, may take place on the retina
brought nearer to the cornea. But if the rays are
exceedingly divergent, they aire refracted with more
difficulty; their convergency takes place behind
the retina, and vifion is indiftind.

In prefbyopia, the fight is neceffarily weak, fince
VOL. III. R -. th$

242 TITAJL FUNCTIOKS.

the objedl muft be didant, and becaufe the mafs
of the luminous rays decreafes in the ratio of the
fquare of the diftance ; fo that an obje6l three feet
from the eye fends to it a quantity of light nine
times lefs than if it were placed at the diftance of
a foot. The difference between a myope and a
prefbyta is, that the former fees only by very di-
vergent rays ; while the other fees by rays almofi:
paralleL

Myopia is corre6led by placing before the cor-
nea a double concave glafs, which refra61s the rays
proceeding in a parallel direftion from a diftiant ob-
ject, and gives them that degree of divergency
which they would acquire if the objed: v^ere at the
natural point of fight. Each cavity ought to be
a fegment of a fphere, the radius of which is equal
to the diftance between the cornea and the point
where the objed would be vifible.

Prefbyopia is corrected by placing before the
cornea a double convex glafs ; this glafs colledls;
the divergent rays, and makes them to fall in a pa-
rallel diredion on the cornea, which refracts them
with more eafe on the retina. The rays which the
pye then receives in a parallel direction are as nu-
merous as thofe which it would receive obliquely
from the fame point of diftance ; the objedl isfeeii
very much illuminated, very diftind;, and appears
larger.

That viiion may be perfecfl, every part of the
eye rnult be in a found ftate ; the membranes and

their

ORGANS OP THE SENSES, ^43

their humours mufl poflefs great tranfparency,
^nd the nerves muft be endowed with their full
vitality.

The fight is weakened or impeded by fpots on
the cornea (fpecks); by opacity of the cryftalline
humour (a catara3) ; by palfy of the optic nerve
(amaurofts) ; by confufion of the vitreous humour
(glaucoma) ; and by all other alterations of which
the different parts of the eye are fufceptible.

The retina, confidered as the efTential feat of
vifion, is an organ endowed with a very fine and
dehcate fenfe of touching ; fince it perceives th'e
impreflion of all the modifications of the light re-
flected from the bodies, and refra<5led on it by the
humours of the eye.

This organ, which cannot enable us to judge of
the magnitude and difi:ance of bodies but by the
aid of touching, is that however which recalls the
greatcft number of fenfations in a given time ; it
brings the individual foohefl into relation with ex-
ternal objefts, by inflantly pafling over very large
fpaces*. This organ, in confequence of habitual
and continued exercife, acquires fo high a degree
of utility and perfection that it is exceedingly diffi-
cult to determine what is its real natural mode of
adlion*

This field of action is more than fufficient to
fatisfy all our wants; but its extent is too limited

* Light is faid to pafs over 164,000 miles in a fecond.

R a to

2,44 .. VITAL FUNCTIONS.

to gratify our curiofity : the eye, indeed, keeps us
as far diflant from the infinitely fraall objetl which-
is "near us, as from the infinitclv ereat one which it
is impofIib]e for us to reach.

34. Hearing. The organ of hearing contifls
eHentially in a nervous expanfion, proper for re-
ceiving the impreffion made on it by thecontadlof
the air, in a lliate of vibration.

The auditory nerve is expanded in the middle of
a vifcous fluid, contained in a membranous cover-
ing, and enclofcd by the ofleous labyrinth,

The labyrinth is compofed of three femicircular
canals, fhaped like the fiiell of a fnail, which have
a communication with each other through the
veflibulum, by means of fix apertures, five of
which belong to the three canals.

The labyrinth has a communication with the
tympanic cavity by two apertures, one of which
is round and correfponds to the bottom of the in-
terior fcala of the cochlea ; and the other proceeds
into the veftibuium. The firil is clofed by a mem-
brane, and the fecond by a fmall bone.

The tympanic cavity communicates with the
bottom of the mouth by a long narrow canal (the
Eufiachian tube). This cavity is fhut externally by
the raembrana tympani.

The membrana tympani correfponds with the

hole of the veilibulum by-iiferies of four fmall

^ boneS;,

ORGANS OF THE SENSES. "245

bones, Avhlch are moved by a few fmall mufcles.
It is the bafe of the ftapes which is. applied to the
hole of the viflibulum, where it is faftened by the
periGileum ; the handle of the malleus is fixed to
the centre of the membrana tympani. All this
apparatus is preceded externally by the auditory
conduit of the ear^ and by its concha,

Elaftic bodies/ ftruck or diilended,jchange their
figure, and return to their nrft ftiate, by vibrations
more or lefs manifefi:. Darins: thefe vibrations,
the integrant moleculce of the bodies experience a
particular movement, a fort of quivering or vi-
bration,which is communicated to thefurroundins:
air, and is propagated to a gi eater or lefs diflancc.

The column of air, thus in a ftate of vibration,
which ftrikes the "ear, produces on the expanfion
of the auditory nerve an impreffion of contadl,
which is comiTiunicated to the brain.

The vibrations of bodies which take place in-
flantaneoufly, or in a confufed and inappreciable
itianncr, confliitute no'ife ; thole which regularly
fucceed each other produce /oK7z.i.

Noife or found always arifes from the entrance
of air into the vacuity, left inftantaneoufly by bo-
dies flruck or diftended.

Air may enter into a ftate of vibration by an
immediate fhock ; and it then produces noife,
found, voice, fpeech.

Sound is propagated in every direcftion with an
R 3 uniform

246 VITAL FUNCTIONS.

uniform velocity, of about 1 142 feet per fecond,
plus or minus the velocity of the wind, according
as it is in a contrary or a favourable dire<ftion.

Sounds which flrike elaftic bodies are refle61ed
• at an angle equal to that of their incidence. Reflect-
ed found exhibits the fame phaenomena as diredl
found, and conflitutes echo. Sound is ftronger,
and is propagated to a greater diftance, according
as the air is more condenfed.

The inteniity and propagation of found increafe^
as the fquare of the denfity of the air,

Tfie force of found is weakened by the hu-
midity of the atmofphere; fo ihat it is propagated
more eatily as the air is colder and drier^

Sound, by being propagated, decreafes in inten-
fity, as the area of the bafe of the cone which it
forms increafes. This intenfity, therefore, is four
times as weak when the diftance is double.

Sound is flronger as the vibrations are greater;
but it remains the fame. Sound does not change,
but when the vibrations are more or lefs numerous
in a given time.

In grave or low, founds, the firings perform fewer
vibrations in the fame time than acute or loud
founds. When the number of the vibrations is
too fmall or too great, the found is not perceptible
by our organs.

' According to Euler, we cannot appreciate a
grave found which has lefs than thirty vibrations,

nor

OE.GANS OP THE SENSES. 247

nor an acute found which makes more than 7552
in a fecond.

Thefe limits offound, appreciable by the human
ear, are included in the octave.

The number of the vibrations depends on the
fize, length, and lenfion of the fonorous firings.
This number of vibrations is in the inverfe ratio of
the length and (ize of the firings ; and in the di-
rect ratio of the flretching forces.

Two firings are in unifon when they perform
exadly the fame number of vibrations in the fame
time, and produce the fimplefl concord.

When an acute found produces exadlly twice
as many vibrations as a grave found, it is faid to
be its o6lave ; and the double octave when it pro-
duces four times as many.

If the acute found produces three times as many
as the grave found, it conftitutes its fifth ; and its
double fifth when it produces fix times as many,
&c.

All the aliquot divifions of a firing give the
harmonic founds of fundamental bafs.

A found is flrong or weak, according to the
greatnefs of the vibrations; grave or acute accord-
ing to their velocity ; and harfh or foft according
to the particular nature of the inftrument.

The quality of the found depends on the nature
of the inflrument, and verv often it is not known
in what it confifts,

R 4 The

248 VITAL FUNCTIONS.

The tone depends on the manner in which the
inflrunient is played, and varies with the artifts.

Sound, }Todnccd either by ftriking a bell or a
ftring, the vibrations of which are communicated
to the furrounding air, or by the immediate
collifion of the column of air, as is the cafe in
wind inftrumcnts, is propagated in a diverging
manner in every dire6!ion.

The fonoroLis rays which fall on the concha of
the ear, are dire£ted towards the auditory conduit,
and ilrike againfl the membrana tympani. The
vibrations are communicated to the air contained
in the tympanum, and arc thence tranfmitted to
the fluid in which the acouftic nerve expands;
and the nerve receives an imprefiion of contad.

This impreffion is propagated as far as the brain^
and iniiantaneoufly produces a general change of
Hate, which is called thefenfation of found.

The movement of rea6tion, which the brain
produces in all the organs, in confequence of the
impreffion made on it by the auditory nerve, is
often very remarkable. Thus a fudden and un-
expeded noife produces a new mode of a61ion,
which is particularly obferved in the mufcles, in
the organs of circulation and refpiration, in the
gaftric fyftem, and even in the Ikin,

In children, a weak found produces very little
imprefTion, though the ear has already acquired
Its whole development. This organ muft be long

exercifed

ORGANS OF THE SENSFS. 245

' (

exercifecl before it can acquire that degree of per-
fedion of which it is fafceptible ; and to many
perfons the fineft mufic is nothing but flunning
noife.

But, when a tender and harmanious found fud-^
deply ftrikes an experienced ear, it immediately
produces a particular change in the whole Ij'ftem;
a fenfation is experienced, as if fomething were
ilowing through every part of the body ; a pecu-
liar flate of fpafm is produced ; circulation and re-
fpiration feem to be flackened ; a fenfe of con-
ftri(9aon towards the epigafcrium is felt, and the
ikin becomes corrugated. '

IMone but perfons feniibleto the charms of har-
mony can be fully acquainted with the change
which may inftantaneoufly take place in the
whole organization, in confequence of enchanting
mufic.

The peculiar cWgSl produced on the organiza-
tion by mufic depends, on the one hand, on the
nature of its compofition, and on the other, on the
feniibility and peculiar difpofition of thote who hear
it ; and in ell thefe points of view it exhibits re-
fults very different.

Mufic has fo powerful an a61ion on the organi-
zation, that it has often been propofed and even
employed with fucccfs in the cure of fonie difeafes.

It is infiirumental mufic, in particular, vvhen
performed in an afFecling manner, which pro-
duces

'250 VITAL FUI^CTIONS.

duces the greateft effed on man. This mufic
feems to maintain, in every part of the body, a
regular motion, which is renewed at each beat of
the meafure ; and as we may fay exalts the or-
ganization to fuch a degree as to make it overcome
the greatefl efpDrts. It is well known how much
the found of the drum faciHtates marching, and
what a degree of courage has often been produced
during the time of a battle by a martial air.

It is in large cities, in particular, that the in-
fluence of mulic feems to be molt remarkable.
A young delicate female, who could not walk a
few miles to a ball, when conveyed thither in a
carriage, is fometimes able to dance four or live
hours without intermiffion.

Were Ihe to fnut herlelf up in a room alone,
and try to jump about in this manner, at the end
of a quarter of an hour fhe would fall down on
the floQr exhaufted with fatigue. It is the muiicj
in a great meafure, which renews and maintains
this a61ion ; the fplendour of the lights and drefles,
and the prefence of a handibme young man, con-
tribute alfo to exalt it.

35. Some have often found it difficult to con-
ceive how feveral founds can be propagated fimuU
taneoufly in the air, and how the ear can perceive
them at the fame time.

When two founds are produced together, they

are

ORGANS OP THE SENSES. 251

are either propagated fucceflively in the moft di-
vitible parts of time, or they combine, unite, and
form only one found, which the mutician always
knows to be the refult of two inftruments 3 or
both founds are diflurbed, become confounded,
and produce only noife, which the ear is not able
to appreciate.

What has been here faid in regard to the fi-
multaneous propagation of two ibunds, may be ap-
plied to that of fifty, and ferves to explain their
mode of a(51ion on the organ of hearing. Two
founds, indeed, produced together, may necefla-
rily reach the ear at periods the nearelt to each
other poffible, and are then perceived one after
the other; or they reach it at the fame time, and
in this cafe produce only a fingle impreffion,
which is neither that of the found A, nor of the
found B, but which refults from the combination
of both, and which often a muiician only can di-
ftinguifh, becaufe he is acquainted with the- for-
mation of them.

It is very difficult to determine what is the ac-
tion of each part of the ear during the perception
of found. The fmall mufcles attached to the
chain of fmall bone?, which extends from the mem-
brana tympani to the aperture of the vellibulnm,
may by their adlion Itretch or relax that membrane;
remove from or bring nearer to the aperture of the

veftibulum

252 VITAL FUNCTIONS.

veftibulum the bafeof the flapes, and thus favour
cr oppofe the propagation of found in the labyrinth :
but all this apparatus is not indifpenfably neceffary
for hearing.

The eflcntial part of hearing, which is found
in all aninials^ and which in a great number is the
only one that cxifts, is the membranous capfule,
containing the vifcous fluid in which the auditory
nerve expands. This nervous espanfion alone
can even tranfinit to the brain the imorefiion
made on it by the contadt of a body in a Itate of
vibration, and caufethat or^^-an to produce tire ge-
neral and inilantaneous mode of aifl'lon which con-
ftitutesthe fenfation of found. The external part
of the ear in man may be removed vidthout great
inconvenience; and the ears of dop-s and horfes,
which are much larger, are daily cropped without
doing them much injury. ' Obiiru6lion of theau-
dito'.y conduit docs not occafion complete furdity j
and though people flop their ears as clofely as
poiiibrej they can ftill hear ibunds of a certain de-
gree of firength.

Hearing relults from a vibratory motion com-
rnunicated to the fluid contained in the labyrinth ;
and this motion may be tranfmitled even through
tiie bones of the,; head, as is the cafe in iifhes,
which have no auditory conduit, and whofe organ
of hearing is enclofed in the cranium.

The

ORGANS OF THE SENSES. 253

The membrana tympani is often found dedroyeda
even with the lofs of fome fmali bones, and yet
deafnefs is not neceflarily the refiilt*

Perfons who have the membrana tympani pierced,
can in fmoking a pipe make the fmoke ilTue from
the ear : in this cafe the fmoke pafies through the
Euftachian tube.

This guttural conduit of the ear, which has
been fuppofed to contribute, in an edential man-
ner, to hearing, becaufe people often liden with
their mouth open *, feems to be deftined for the
purpofe of affording a free entrance to the air
into the tympanic cavity.

Though all the acccffory parts of the ear are
not abfolutely neceiiliry foi; hearing, they together
Contribute a great deal tou-ards Ihe perfeftion of
that fenfe ; and the deftruclion of them tends al-
ways, more or lefs, to weaken it. Deafnefs is the
neceffiiry refult of the lofs of that fluid contained
in the m.embranous labyrinth : in the bodies of
fome old men, who had continued deaf for feveral
years, the ofTeous labyrinth has been found empty.

The fluid of the labyrinth may be effufed into
the tympanum, by the deftru61ion of the mem-
brane which flints the aperture of the concha, or
by the removal of the flapes, the bafe of which
fliuts the aperture of the veftibulum ; and thefc
accidents mult neceiTarily produce deafnefs.

* Conticuere omnes, intentique ora tenebant.

Weaknefs

254 VITAL FUNCTIONS.'

Weaknefs of the auditory nerve occafions dull-
nefs of hearing ; a pallied Hate of it gives rife to
complete deafnefs.

The fpiral of the two fcalas, which the concha
exhibits, has induced fome to beheve that it ferves
for receiving nervous cords, of different fizes, in a
flateoftenfion, and fufceptible of entering into vi-
bration and of putting themfelves in unifon with
different tones ; and that under this point of view
the ear refembles a harpfichord. But this fyflem
of extended cords, which would be ufelefs in the
midft of a fluid, is not to be found. The concha,
which does not exifb in all animals, and which
varies in its form in different claffes, feems to be
deftined only for the purpofe of prefenting a
greater furface to the expaniion of the auditory
nerve.

The only condition neceffary for having the fen-
fation of found is, the impreffion of contact made
on the nervous expanfion^ by the vibrations of the
medium in which it is placed.

The organ of hearing, which alone leaves only
the vague fenfation of a change having taken place
in the ear, becomes of the greatefl utility by its
fimultaneoiis exercife with the other fenfes, and
concurs in an eflential manner towards the pro-
grefs of civilization, as it makes men to communi-
cate, in a direct manner, with each other, by means
of the voice.

S6, To

ORGANS OP THE SENSES.' ^ ^55

36. To comprehend properly the progrefs fol-
lowed by the organs of the fenfes, and by the
mufcular fyfiem in the development of their func-
tions, and in their individtial orfimultaneous a<5tion,
thefe organs muft be obferved in children at the
period of birth ; and their progrefs muft be traced
during the firft years of life and to the age of man-
hood.

At the nrtoment of birth the foetus, habituated
to a refidence in the matrix, where it is furrounded
by a fluid at the fame degree of temperature, and
in continual reft, without refpiration and digeftion,
receives at its birth a fudden and lively impreflion,
by the contaS: of folid bodies, by that of the light,
by the change of temperature, and from the air
which ftrikes it externally, and which is introduced
into the lungs. The general change which is
.thus efFedled in all the organs, reduces it to a ftate
of unealinefs,' which determines the firft move-
ments it makes and the firft cries it emits.

Soon after, the gaftric fyftem makes it experience
an uneafinefs which arifes from- a new want. All
the parts of this fyftem enter into adlion, and re-
quire the prefence of that aliment on which they
are deftined to be exercifed.

The mufcular fyftem, at firft, performs only fud-
den and uncertain movements. The aftion of
the flexor mufcles, whicli is ftronger than that of
the extenfors, keeps the limbs in an habitual ftate

of

25G VITAL FUNCTIONS.

of flexion. If the child be placed upright, its ab-
dominal limbs perform alternate movcmeais of
fiedion and ezreniion, and ftretch themfelves
againil the reliflance of the ground. Th&ir arms
move in every dire6iion, and their fingers, habi-
tually bent, grafp with violence every body that
falls in their way, were it even a piece of hot iron.
All thefe trials develop the function of the muf-
cular tj^ftem, and prepare it for more regular move-
ments.

The eyeSj at firft, troubled and confufed, become
brighter, and begin to be ftruck. by the impreffion
of the ilrong light, and then by very luminous
bodies and by fplendid colours: this impreffion
gradually becomes diftindl, and the hands, already
habituated to grafp, make further efforts for that
purpofe ; the child then extends Its arms towards
the luminous object, and feems delirous to touch
it, at whatever diftance it may be.

In this cafe, the eye only learns that an objedl
exills in the direftioji of the vifvial axis ; the hand
is direcied thither, reaches it, touches it, and thus
afcertains its diftance, its form, and its volume, S:c,
The cafe is the fame with the organs of the
other fenfes I they all mutually affift each other?
and their individual perfediion is the refult of their
fimiultaneous adlion.

3 7. The apparatus of locomotion, and the diiFerent

fy items

ORGANS OF THE SENSES. 257

fyftenis of the fenfes, the fundlions of which we
have examined, are the organs which in an effen-
tial manner eftablifh a relation between us and
external objefts. The aggregate of them, which
conflitutes relative life, gives for refult a feries of
very remarkable phaenomena. The central fyftem,
by means of the nerves, diftributes to them the
efTential principle of life. The impreflion made
on thefe nerves is tranfmitled to the centre of the
cerebral fyflem and modifies its adlion ; fo that the
adlion of the organs of motion and of the fenfes
is fubordinate to that of the cerebral lyftem, as
that of this fyflem is fiibjecSled to different impref-
fions, communicated to it by the nerves of thefe
organs.

The impreffion made on the nerves of any part,
by the contacSt of fome foreign fubftances, may be j
tranfmitted to the centre of the cerebral fyltem,
^nd modify its natural adlion.

For the moft part, the new mode of action is
particularly remarkable in the funftion of the or-^
gan which has received the impreflion. At other
times, it appears in a diftant part, and fometimes
it announces itfelf by an univerfal and uniform de-
rangement.

The new mode of adion which refults from
every change in the brain may become the caufe
of a new a6lion, which continues i fo that the de-
rangement is continued by the confequence of

VOL. Ill, s iti

258 VITAL FUiJCTlONS.

its firfl rcfult : fuch is the cafe in almoft all
difeafes.

38. Senfations being the refult of every fudden
change which takes place in the whole of the or-
ganization, it is obferved thcit children do not be-
gin to give apparent figns of them, until this
change is fufficiently ftrong to reduce them to a
ftate of uneafinefs. All their firft fenfations, indeed,
are painful, and are announced by cries and move-
ments. This (late of fufFering, in which the child
is 'placed in confequence of its firft fenfations, is
neceffary to excite it to adts which mud contribute
to its prefervation, othervvife, after being born, it
would fufFer itfelf, through indifference, to perifli.
But there (bon take place in its organization changes
of fuch a nature, that they are capable of deftroying
it, and which reduce it to a fiate of uneafinefs it is
incapable of fupporting. It moves at random to
change its pofition, in order to fatisfy its wants, and
pain becomes to it the firfi caufe of all its a6lions.

Inftead, therefore, of pitying in a ridiculous
manner the fate of the human race, who are faid
to be born to fuffer, and whofe firfi figns of life
are announced by cries, we ought to confider thefe
cries, and the pain which produces them, as the
firft caufe of the rapid development of all our fa-
culties.

One of the mofi: afionifhing phenomena of the

organizatio_n^

ORGANS OP THE SENSES. 25Q

organization prefents itfelf even at this early pe-
riod : the living being has a ftrufture which muft
develop itfelf in a determinate order. When this
order is effentially deranged, all the fyftems of
organs experience an extraordinary movement ; a
peculiar rea6lion, v^^hich lafts till calmncfs is re--
liored, or until the equilibrium be entirely de-
llroyed.

The general orparticularftateofdiforder, of which
the whole of the orgaiiization is confcious, and which
conftitutes ihc fenfation of fain^ is indeed the jnofl
important and mofl wonderful phEenomenon of
life. The impreffion of contadi:, made on the or-
gans of the fenfes, is tranfmitted to the brain by
means of the nerves, and produces there a new-
mode of adion, the refult of which is a certain
change of ftate in the whole organization. This
change of ftate, which conflitutes fenfation, may
be inftantaneous or continued for a longer or
(horter time ; and in either cafe it eflentially varie;s
in three ways, ift. It tends to derange the natu-
ral order of the fundlions, and conflitutes the
gainful fenfation. ad. It tends to ftimulate the or-
gans in a proper manner, and to exalt their habitual
adlion, which it caufes to be exerted in a fuller
manner, and conftitutes the agreeable feffailon,
jjd. It does not fenftbly difturb the natural order,
and yet conftitutes an appreciable change of ftate,
which is the ftmpk fenfation. The painful fenfa-

s 2 tions

260 VITAL FUNCTIONS.

tions are the ftrongeft and the firft felt ; the agree-
able fenfations cannot be well appreciated but by
repeatedcontraft with the painful fenfations; without
the latter the agreeable fenfations would be merely
the natural a6tion of the functions, exerciling it-
felf with more or lefs intenlity. In the lafl place^
the frequent and fully-perceived alternation of the
changes of ftate, refulting from a perturbation of
the tun61ions and from their natural a^ciorj;, per-
formed with more or lefs energy, gradoally en-
. ables us to appreciate changes of ftate^ though in-
different in regard to t lie organic order.

As the child grows up, and its organs are de-
veloped, it is enabled, by habit, to appreciate bet-
ter the new modes of a6iion which take place in
its different functions ; and it at length becomes
fenfible to the flighlefi: changes which are pro-
duced in its organization.

After a certain period, the child finds that it has
experienced agreeable and painful fenfations ; it
makes an effort to avoid every thing which has al-
ready reduced it to a ftate of fuffering, and endea-
vours to replace itfelf in thofe pofitions which it
before found favourable.

Thus, to avoid pain and to obtain eafe are the
firft elements of its education.

At this period, one begins to obferve that thefe

lenfations are renevi-'ed without the prefence of all

thofe objects which at firft produced them. This

_ phse-

ORGANS OF THE SENSES. 201

phenomenon, which is undoubtedly the moft im-
portant, and the moft neceflary to improvement,
requires to be carefully confidered.

39. In order to comprehend properly how a
fenfation may be entirely renewed, merely by the
prefence of a part of the objects which firll pro-
duced it, we mull keep in mind that the apitude
Oi the organs to difcharge their functions increafes
by exercife ; that they have all a great tendency
to habit, to perform the fame a(5lions, and are en-
dowed with a great force of imitation.

We, indeed, know that the organs are
ftr-:nglhened arid improved by a proper exer-
cife of their funftions ; and that at the end of a cer-
tain period they all perform with- eafe thofe actions
which at firfl were attended with a great deal of
diiiiculty.. Thus, the mufcles which, at firft, per^
form only fudden and irregular motions, give by
long habit and continued exercife movements, the
variety* agility, and fafety of which are inconceiv-
able, as is obferved to be the cafe, in tumblers^
dancers, organills, &c.; and it is to be remarked,
cseteris paribus, that the muiician, for example,
who performs bed a piece of mufic on the piano-
forte and the violin, is always he who has exer-
cifed himfelf moft on thefe inftruments ; and that
in this department, as well as in others, it is al-
ways by long exercife that people are able toover-
§ 3 coms

^62 VITAL FUNCTIONS.

come great difficulties, independently of the
greater or lefs faculty which refults from an advan-
tageous prganic difpofition.

What has been here faid refpeding the mufcu-
lar apparatus, may be applied to all the reft, and in
particular to the cerebral fyftem, the functions of
which I fhall here endeavour to explain.

Of all the iyftems of fundions, that moft habi-
tually in a6lion, no doubt, is the cerebral fyftem,
fince it is continually diftributing to all the parts
the principles of life, by means cf the nerves;
and is continually receiving the impreffion made
on thefe nerves by foreign bodies. I have already
faid that the change of ftate, refulting from an im-
preffion tranfmitted to the cerebral organ, and
which conftitutes fenfation, does not appear to be
felt by the child until this change is fufficiently
ftrong to produce a confiderable derangement in
its organization ; that the child then becomes fenft-
ble to the impreffion of objeds which tend to fa-
tisfy its wants, and to caufe its funtlions to be per-
formed with more energy ; and that it at length
becomes able to appreciate a change of ftate which
does not difturb the order of the fundllons.

When the child begins to receive thefe three
orders of fenfations (painful, agreeable^ Q.ndjimple)y
it is obferved that the fimple fenfations are at firft
few in number, but that they embrace fimultane-^
oufly a great number of particularities, not per-
ceived.

ORGANS OP THE SENSES. 26S

ceived, which gives reafon to believe that children
generalize: in proportion however as the fenfa-
tions are repeated they become complex by an ana-
lyjis of the principal obje£b.

Thus a child begins to fee in its mother a wo-
man, and all women make it experience the fame
fenfation ; but it fees its mother every day, and
almoll during the whole day : this fenfation, there-
fore, which is fo often repeated, allows the child
to receive particular fenfations by obferving her
height, her features, her drcfs, the found of her
voice, the care five pays to it, &c. All thefe par-
ticular fenfations remain united to the general fen-
fation, and arc fimultaneoufly repeated.

The cafe is the fame in regard to all the objedls
with which the child is continually in relation: their
prefence, at firtl, makes it experience only ona
fenfation, but which is afterwards rendered complex
by the fucceflive difcrimination of the different
parts which conftitute it. All thefe particular fen-
fations are always connected with the principal
objed, and are conllantly renewed in the order
in which they are acquired,.

A feries of fenfations, produced by an object and
its attributes, is then renewed entirely by the force
of habit, on feeing one of the fm al left circum fiances
which were conneded with it, or merely by the
light of an objeft which exhibits any refemblance
or analogy to the firfl.

s 4 Thus

l64 VITAL FUNCTIONS.

Thus a fcries of lenfations mull be confidered
as a peculiar aft of the funftion of the cerebral {yf-
tern, and of which the individual is confcious by
the dire6l relation which this fyftem has with the
whole organization. This feries of fenfations is
then repeated with the more facility, the oftener
they have been excited. They may be entirely re-
newed, not only by the prefencc of the principal
obje6l which contributed to their formation, but
by all its accefibry circumftances j by every thing
which has a more or lefs dire6l relation with it, gr
a certain refemblance and fort of analogy to it ;
and as there is no feries of fenfations, a part of
which is not connected in fome points with another
feries, it thence follows that they may all be re-
newed by each other, according to the relation-
which exifts between them.

At the end of Tome years, the child which, by
exercifing its organs of the fenfes and of motion
on all the objedls around it, has already experienced
a numerous feries of fenfations, fulceptible of being
renewed with great facility, and which, on the
other hand, isirrefiltibly excited to adion in order
to withdraw itfelf from pain, and to fatisfy its
wants, is foon capable of comparing its prefent fen-
fations with fenfations recolledied, and of com-
bining them in a manner mod proper for its pre-
fervation. It is thus that the firll operations* of
the underftanding feem to be performed. When

the

ORGANS OF THE SENSES. 2()3

the development of tbefe operations is well under-
ftood, it will be eafy to trace the progrefs of thofe
which refult from the fucceffive improvement of
the intelle£lua,l organ ; for it is not fo difficult to
determine in what manner man has attained to the
higheft degree of improvement, as to conceive
how he began to combine the iirfl two fenfations.

40. Among people lefs advanced in civilization,
as the inhabitants of New Holland or the favages
of America, the child during the firft year of its
life muft exhibit nearly the fame feries of phaeno-
mena as among more enlightened nations; but the
further development of their organization is very
limited, efpecially in regard to intelligence ; and
man, in thefe countries, has only that degree of
fuperiority over other animals which naturally re-
fults from an organization evidently more advan-
tageous.

The people of thefe countries, indeed, notwith-
ftanding their antiquity, have ftiil a language ex-
ceedingly limited ; they are fcarcely acquainted
with the art of conftruding huts ; they feed on fifh,
game, and the natural produdions of the earth ;
and none of them have carried their induftry fo
far as to preferve animals for increafing their breed :
in a word, the inftruments of the greater part of
thefe tribes are as yet exceedingly rude.

It is to be remarked, that thefe people inhabit

the

26^ VITAL FUNCTIONS.

the fined: countries on the earth ; and it is pro-
bable, that this circumftance has been an obftacle
to the progrefs of their improvement. I have aU
ready faid, that in a child the firll excitement to
a^lion^ the firft thing that promotes its education,
is the neceffity it experiences of withdrawing itfelf
from ^ain, and of fatisfying its*wants.

The man continues to experience the fame prin-
ciples of adion, and is ftill excited to induftry by
the neceffity of preventing or repelHng the attack
of his neighbours, or by the delire of invading
them to feize on the fruits of their induftry. But,
in a fertile country, which furnifhes for its few in-
habitants abundance of food without much labour,
and which being of a mild temperature does not
reduce them to the neceffity of fecuring them-
felves either from intenfe cold or exceffive heat,
man has no motives fufficiently powerful to induce
him to make a rapid progrefs towards improve-
ment.

Among thefe people, the progrefs of the de-
velopment of the different organs being very in-
confiderable may be readily conceived ; but in
feme countries of Europe man, during a great
number of ages and continual revolutions, ac-
quires fuch a degree of improvement, that he can
no longer difcover the point from which he pro-
ceeded, nor trace out the path which he purfued.

41. I flial!

ORGANS OF THE SENSES* ^^7

41. I fhall not here enter into a long detail of
the ilow and facceffive progrcfs which nnan muft
liaye made before he could attain to his prefent
degree ; of in telle6lual improvement; this labour
v/ouid be tirefome and ufelefs. Having exhibited
a vie'A' of the manner in which the intelle6lual fa-
culties are tirft developed among different orders,
and having given a Abort defcription of the ftatc
of man among the moft ignorant tribes, I (hall
purfue the further development of the humaa
mind among the mofl civilized nations.

The child which is educated among an enlighten-
ed people learns, at an early period, to employ that
inilrument which becomes to him the grand means
of communication and of improvement. Lan-
guage has not been given to man, like hearing and
feeing, as is commonly fuppofed ; it is the floMT
and laborious refult of his induftry ; it is one of
the great difficulties which he has been able ta
overcome.

I/O fpeak is a thing fo difficult, that children, if
not early acculiomed to it, are fcarcely able after-
wards to acquire the faculty of fpeech, as has' often
been obferved in individuals educated alone in the
woods, and as may be feen at prefent in regard to
the favage of Aveyron. This child, who poiTefTes
a good common underflanding, finds it exceed-
ingly difficult to pronounce a few words ; it wa«

much

iftiS VITAL FUNCTIONS.

much eafier to make him comprehend that we ex-
prefled things by written figns, and to teach him
thefe figns, than to make him pronounce the founds
which exprefled them. Thus, when he is about
to walk to the obfervatory, where he fometimes
receives milk, he takes his copper letters in his
pocket, and combines, before the perfon w ho gives
him the milk, the four letters which reprefent that
fubftance. Speech rcfults from the fucceffive
and limultaneous adlion of a great number of fnnsl!
mufcles. This adion is exerciled in fpeaking v/ith
a mobility and preciiion which can be acquired
only by long exercife ; fo that it muil be as diffi-
cult to teach a perfon to fpeak, who has fpent the
firft twenty years of his life alone in the woods, as
to make him play on the harpfichord.

What itill further proves that language is merely
3 human acquifition, and that man does not na-
turally fpeak with facility is, that perfons born deaf
are always dumb.

What valuable advantage the child derives from
its intimate relation with its mother, who is con-
tinually under theneceffity of fpeaking to it, and
who always points to the obje6l when (he pto-
nounces the word which exprellesit? The child is
thus irrefiftibly ejjcited, by its propenfity to imita-
tion, to make an effort to pronounce the lame found.
The organ in developing itfelf is properly modi-
fied

ORGANS OF THE SENSES.' 2§^

fied for that exercife, infeniibly contrails a
habit of it, and at length appears to have acquired
it without difficuly.

The propenlity to imitation, which in children
is very great, would be continued with age, as in
apes, were not its place occupied, fooner or later,
by a defire of a6ling according to the dictates of
the will.

This tendency appears to be merely an exten-
iion of the faculty and of the need of involuntarily
repeating actions which are familar to us ; and is
extended even to aftions which we fee performed.

At the end of fome years, when the child has
beard pronounced, and has itfelf repeated, a great
number of times, the words which reprefent all the
obje6ls with which it is in relation, and when it
has contra61:ed the habit of applying them fpeedily,
and with eafe, to the things represented ; in aivord,
when it begins to fpeak, its inftruftors do not fail
to teach it that all thefe words are reprefeated by
conventional figns. By long exercife it at length
becomes able to diftinguifh them with eafe, and to
follow with rapidity theircombination in the forma-
tion of phrafes ; and at laft acquires the habit of
delineating them itfelf: that is to fay, it ;can read
and write. When potlelled of thefe inftruments>
and when they have become very familiar to it,
the fun6lion of its intelletilual organ loon becomes
extended, and in the development of it all the

principal

27© VITAL FUNCTIOKS.

principal phagnomena of intelligence may be ob-
ferved.

42. It has been already repeated feveral times,
and it ought never to be forgotten, ibat fenfations
are the refult of an imprefiion tranilxiittpcl by the
nerves to thebraiDj which experiences a Dew mode
of a6{:ion, followed by a general and inftantaneous
change of ftate in the whole of the organization.

Senfations are dire6l or recolle6led. Recol-
ledled fenfations are more particularly diflinguiHied
by the name of /V/^^j.

Ideas are always renewed in confequence of
fome direfl: fenfations which recall them. The fa-
culty of recalling a more or lefs extenlive feries
of ideaSj in confequence of a fmall number of fen-
fations, confiiitutes memory.

When we have acquired a great number of differ-
ent fenfations, every thing which furrounds us may
recall them every moment; and we may continu-
ally experience a thoufand incoherent and incon-
gruous fenfations. This, indeed, is the cafe with
manyperfons, and particularly with children, who
are then faid to be fubje^l to diJtraBlon.

The faculty of recalling all thofe ideas which
have been acquired, in regard to any obje61:, ex-
clulively of thofe which have only a very diftant
relation to it, conllitutes attention.

This faculty is one of the moft difficult io be

obtained.

ORSANS OP THE SENSES. ^71

obtained. It is acquired by long habit and clofe
application to one particular fubjedl ; it is one of
the conditions mofi: neceflary to the improvement
of the underftanding. Vicq-d'Azyr is of opinion,
that the greateft obftacles to the improvement of
apes, arifes from their di fraction and great mo-
bility.

43. When a child has feveral times experienced
a certain number of fenfations, he foon begins to
comh'me them, and to a£i agreeably to the refult of
that combination. The development of the faculty
of combining^ which is properly that of the under-
ftanding, is the moft important to be obferved.

I have already faid that the firft fenfations of a
child are painful. By thefe fenfations it is irrefifti-
bly excited to ad^ and to cry. It then begins to
move at random, and to fend forth cries until the
pain be allayed or the want fatisfied.

After the painful fenfitions, it is foon obferved
that it experiences fenfations of eafe ; and that it
finds in the means proper for fatisfying its wants s
fource of enjoyment and happinefs.

At the end of fome time^ when the fame adions
have been often repeated, it is obferved that fen-
fations begin to be renewed in the child, without
the concurrence of all thofe circumftances by
which they were at firft produced. Thus the

flight

273 VITAL FUNCTIONS,

fight of the mother, who has often fatisfied its
hunger, by exciting an agreeable fenfation, recalls
to the child a feries of fenfations already expe-
rienced. It dwells ii^on thefe renewed fenfations ;
becrins to have attention, and thus learns to th'nik.
While it thus dwells on its firft fenfations, others
relating to the circumftances which accompany
the a(fl of la61:ation are renewed ; it endeavours
to fatisfy a want, to place itfelf again in an agree-
able fitiiation : after this period it combines fenfa-
tions with ideas j it judges and reafons j it then
determines in confequence of its judgment, and
thus produces an adl o( volition. It is iiadeed ob-
ferved that it wiflies to approach its mother, and
that it makes an effort to lay hold of the breafl
with its lips.

If the firft ads of intelligence in the child be
thus carefully and minutely obferved, and if the
connedion of them be properly followed, it will
be feen that they are the neceflary refult of diffe-
rent known properties. Thus it is remarked that
the child a£ts, becaufe it is irreliflibly excited to
do fo for its prefervation, by the ftimulus of pain ;
and that it combines the prcfent fenfations with the
pad, becaufe fenfations are renewed without the
prefence of the principal objeft, and merely in
confequence of fome circumftances connefted with
it, and which recall it. But if, inftead of following

this

ORGANS OP THE SENSES. 27$

this pro^efs, we take the flrongcft a6l of the hu-
man intelligence, and endeav^our to difcover there
the formation of the operations of thought, we
fhall find nothing but an immmfe ahyfs^ and lofe
ourfelves in conjedUire.

44. Having followed, in the child, the con- '
ne6lion and fucceffion of thefirfi: aftsof the func-
tion of its intellectual organ, employed almoft
exclufively in fatisfying the firft wants of life,
we dt' length come to the period at which it be-
gins to feiijdy'all the advantages of fadtitious ligns,
and to employ language with facility. We may
then eafily judge in what ratio the progrefs of its
intelligence muit increafe.

By purfuing our examination of the organic
phsenomena fiill further, we fhall find the firft
caufe of action which^ as already faid, is' the ir-
refiftibfe tendency to avoid pain, to fatisfy wants,
and to obtain eafe, joined in fucceffion by many
other principles of adion, in fondnefs for power
or for refpe6l ; in the defire of acquiring know-
fedge, arid in that of gratifying all our fa6titious
wants,' ail habits. Sec' It is obferved, that the
means of fatisfying thefe wants are developed
along with them, and that they are merely an
cxtenfiori of the firft faculty of providing for our
prefervation, by a concurrence of adtions more oc
lefs ftrongly combined.

VOL. III. T ' A more

274 VITAL FUNCTIONS.

A more profound examination of the phseno-
mena which refiilt from a combination df fenfa-
tions and ideas belongs to metaphyfics, and does
not fall within the plan of this work.

Metaphyfics ought to be only a neceflary con-
fequence and continuation of phyfiology; and
when not founded on a knowledge acquired in
regard to the organization^ it will be unintelligible
to all thofe who cultivate the exa6l fciences.

45. It has been already faid that fenfations al-
ways confifl in a new mode of action, produced in
the cerebral organ, the refult of which is a general
and inftantaneous change in the whole of the or-
ganization, and fenfations have been diftinguifhed
into three kinds. In the firft two, the change of ftate
tends to difturb the habitual order of the func-
tions^ or to favour it (gainful and agreeable fenfa-
'iions)\ and in both thefe cafes an adlion is pro-
duced on a part. A fenfation of pain or of ea-
linefs is experienced in an organ. \x\ ftm^U Jen-
fation there is {lill a general and inftantaneous
change of flate ; but without perceptible altera*-
tion in the natural order of the fundlions^ and
though a fenfation is produced, the nature of the
change which has taken place cannot be appre-
ciated, nor is the feat of the fenfation known.

There however can be no doubt that fimple
fenfations arife frorn a general and inftantaneous

change

pilGAlTS OP THE SEIfSfiS. 275

^liange of ftatej and this change, which is not habir
tually perceptible, becomes very appreciable when it
has more intenfity. Thus, of the fenfations which
we, receive by the eyes and the ears, when foine of
them fuddenly recall a feries of ideas which intereft
us in a lively manner, this change of ftate then be-
comes condderable, and eafy to be appreciated.

Under thefe different circumdances, a fenfation
as if fomething liquid or cold were circulating
throughout all the parts of the body is experi-
enced ; a fenfation of fudden cold, of violent
heat with perfpiration, or an oppreffion towards
the epigaftrium are felt. Sometimes this derange-
ment is fo fudden and ftrong, during extreme
joy or a tranfport of paflion, that it may produce
lyncope and even death.

The phsenomena refulting from the habitual
exercife of limple fenfations are commonly indir
cated by faying : the influence of the moral part
on the phyfical, which in regard to many perfons
denotes the influence of nothing on fomething j
but it is evidcjit that Ample fenfations, or fenfa-*
lions unaccompanied with any remarkable de-
rangement of the funftions, are of the fame
order as thofe which are accompanied by changes
in thefe fun61ions: they are all equally the refult
of a new mode of action, excited in the .cere-
bral organ, which product a general and in-^

T % ftantaneous

27^ Vital functions.

ftanlaneous change of flate in the whole of the or-
ganization.

46. To experience a fenfation, ' which may be
conveniently compared and produce confcioufnefs
of the change of ftate which has taken place in
the organization, it is necellary, ift. That the
cerebral fyllem fliould be found, and in full vi-
gour : no diftindl fcnfation indeed is experienced
in difeafes accompanied with a derangement of
the cerebral organs. 2d. That the nervous com-
munication, eftablifhed between this fyftem and
the organ which receives the impreffion, fhould
not be interrupted ; for if the nerves of one part
be tied, cut, or palfied, the imprellions made on
them produce no fenfations. 3d. That the organ
fhould be in a particular Hate of adion which
conftitutcs 'vigilance ; for to make a perfon hear, it
is not fufficient that you fpeak to him, he muft
alfo hear : it is to hear that the part enters into a
fort of tenlion proper for that purpofe ; the cafe is
the fame with the other organs, though in a
manner lefs fenfible. When the organs of a
perfon are not fufficiently diftended to perceive,
it is faid that he is inattentive.

All perceptions, experienced without thefe con-
ditions, cannot produce confcioufnefs ; and the
movements they occafion are not the refult of

volition,,

ORGANS OP THE SENSES. 277

volition, but of the force of habit, in confequence
of the new mode of aftion tranfmitted to the
brain.

47. When the organs of the fenfes^ after long
and fevere exercife, can no longer preferve that
degree of tenfion necefiary for^ perception, they
fall into a fort of collapfiis, and- pafs to a Hate of
reft which conflitutes fleep.

Sleep is not produced by the repofe of fome
organs exclufively, but is the more complete ac-
cording as a greater number are in that ftate of
collapfus ; and it is to be obferved that almofl
all the organs may be in a6lion in different Hates
of lleep.

Thus, the organs of loco-motion are in a6lioii
during fomnambulifm ; and a perfon during fleep
may be affected by the fenfes of fmelling, tailing,
and touching. Some fpeak in their fleep, and if
aflced any queftion they fometimes give a direft
anfwer, which proves that they hear. The fenfe
of feeing is the only one which does not per-
form its fundlions during fleep in regard to ex-
ternal objedls. The caufe of this feems to be,
that the organ of feeing fuddenly procures a very
great number of fenfalions at a time, which al-
ways tend to awaken. It is well known that the
organs of generation are often put into a£lion in

T 3 the

^7^ "^TITAL FUNGtiONS,

the time of fleep, efpecially during lafcivious
dreams, and in the feafon of love.

It is ahnoll needlefs to mention that the fanc-
tions of the organs of circulation, refpiration,
^nd digeflion, as well as of thofe of fecretion, are
liot interrupted in the time of fleep.
' Thofe adtions, which are the habitual refult of
Recalled fenfations, may be produced daring fleep,
by the force of habit, when that change or ftate,
which generally conftitutes thefe fenfatlons, is re-
newed in the brain by certain circumftaDces.

Thefe adions. confift in a combination of re-*
called ideas ; and foraetimes in the exercifes na-
turally refulting from thefe ideas, as is oblerved in
the Cafe of fomnambulifm and of dreams.

7f the change of ftate, reproduced in the brain,
be analogous to that which the optic nerves have
made it already experience by the fight of any
obj'cft, the individual will believe that he Itill
fees it. The fame thing may take place in re-
gard to the other fenfes.

As a fenfation renewed may recall many others
which have accompanied it, a fingle one may re-
produce a feries of ideas, fometimes well arranged,
and often very incoherent or ridiculous.

If the change of ftate in the brain happens fud-
denly to vary, the individual will immediately ex-
perience another order of fenfations, ^hich may

have

ORGANS OF THE SENSES. IJ^

have no relation with the former ; and if thefe
new fenfations are of fuch a nature as to affe6t
him in a lively manner, they wmII determine the
habitual a6lion of the organs : he will fpeak and
even rile up to perform things agreeably to the
ideas which are renewed.

When a perfbn agitated by lively affections is
afleep, the heat of the bed, an uneafy pofition, or
difficult digeftion, may occafion a change of ftate
in the brain, which will be fufficient to produce
dreams.

. It is obferved, casteris paribus, that fenfations
which arc moft frequently renewed during fleep,
are livelier and make a ftronger impreffion than
thofe experienced while awake.

48. To combine, properly, fenfations acquired
in a ftate of watchfulnefs, the organs which per-
peive, and the cerebral fyflem to which the im-
preffion is tranfmitted, muft be in that perfect
ftate of equilibrium which conftitutes health.

If the fundlion of the cerebral fyftem be de-
ranged or difturbed, it cannot properly perceive
the fenfations received by the foundeft organ j
and every thing will appear to have the im-
preffion of that difordcr which prevails in the
brain.

Such, in all probability, is the very fimple rea*

fan of the derangements of the intelledual organ

T 4 obferved

■280 VJTAL FUNCTIONS.

obferved during paroxyfms of hyflerics, hypo-
chondriafis, melancholy and mania; andofthofe
obferved in a great number of difeafes. from the
flighted dehrium to the mofl dreadful convul-

lions.

49. It is to be obferved, that the changes of ftate
which take place in the whole organization, in
~ confequence of impreffions received, and the dif-
ferent movements which thence refult, are of two
forts : \ye have a confcioufnefs of the one ; and
the others take place^ as we may fay, without our/
knowledge.

The changes of date of which we are confcious,
are thofe only which can be agreeable or painful
to us.

Thofe which take place without our knowledge,
are exceedingly numerous : fomeof them depend
on the natural a(?i:ion of the parts ; of this kind
are the movements of the different organs of cir-
culation, refpiration, and nutrition ; but if we
have no confcioufnefs of the habitual adion of
Ihefe organs, we experience a very fpeedy fenfa-
tion of their derangement : the reft comprehend
thofe diforders which depend on a derangement
of the cerebral f){lem ; they often produce acci-
dents exceedingly dangerous, and even death,
without our being confcious of them, as in the
eafe of epilepfy, afphyxiee, apoplexy, &;c.

" Thefe

ORGANS OF THE SENSES. 2§1

Thefe general conliderations on the fundlion
of the cerebral fj-ftem, and on the different
modes of fenfation, are fufficient to give a pretty
corre(?i: idea of them. I fhall therefore not ana-
lyie thein any further, as this would lead me to
details in the more obftrufe parts of phyfialogy,
which would be improper in an elementary work
of this nature. '

ACTION

[ 282 ]

ACTION OF THE SYSTEM OP
DIGESTION.

5©. 1 HE human body increafes, develops itfelf,
is fupported and modified every moment, at the
cxpence of the blood, which, in the uninterrupted
courfe of circulation, furnifhes to every part of
the organization the materials proper for the dif-
ferent changes which are continually taking place
in it.

The blood repairs its lofles by the produd of
digeftion.

The aliments, introduced into the digeftive
organs, make their way through them in a flow
manner. During their flay and their paflage
they become penetrated with the juices fecreted
by the mucous furfaces of the alimentary canals,
and furniQied by the glands ; and they are gra-
dually converted into a pafle of a homogeneous
appearance, which contains the chyle.

The chyle, taken up by the abforbent or chyli-
ferous vellels of the famiC furfaces, becomes after-
v;ards mixed with the venous blood.

The fubftances fufceptible of being digefled^
are all thofc which arife from organized beings ;
vegetable and animal fubilances, and thofe which

7 "^-

ACTION OF DIGESTION. 283

enter into the compofitlon of the fame fubftances j
fuch as water^ atmofpheric air, &c.

The exercife of the gaftric lyftem is excited by
the painful fenfations of hunger and of thirft.

When the need of ahments begins to be (dtf
the individual firft experiences a difagreeable fen-
fation, which announces that the gaftrio organ re-
quires to be exercifed, and that it is difpofed to
perform its function in a complete manner. This
firft fenfation (appetite) is the beft feafoning for
every kind of food.

But if a perfon remains feveral days' without
eating, he gradually experiences a fenfation of
ardour and twitching towards the epigaftrium ;
perfpiration decreafes, circulation and refpiration
become flower, and the individual falls into a
ftate of great weaknefs acconnpanied with anxiety.
At length, if this ftate continue, it produces death
after dreadful convulflons, and the body pafles
Ipeedily to a ftate of putrefadtion.

That need, called hunger, is ftronger the more
active the life, and the more confiderable the lofles
which the body fuftains : it is increafed at the ufual
hour of meals, and by all thofe obje6ls which re-
call the remembrance of aliments. It decreafes, or
is inflantaneoufly fufpended, by every poMierful
diftradlion ; by the prefence in the ftomach of in-r
digeftible fubftances, and by compreffion of the
abdomen.

During

2t84 VITAL FUNCTIONS.

. During hung-er, the ftomach, completely einpty,
is contradtedj and becomes reduced to a very
fmall volume» This ftate muft check circulation,
^nd produce a painful reftraint in the nerves ; the
jrefult alfo is that the liver and fpleen, being lef^
fupported, will twitch the diaphragm, and all
ibefe changes '{till contribute to incrcafe the un-
e^finefs.

, A great many inftances are mentioned of abfii*
Ijence continued for feveral months, and even
for feveral years. This may be conceived in the
following manner : When a perfon dies of hun-
"gerj be does not perifh by being exhaufted in the
fame manner as a lamp is cxlinguifhed for want
©foil ; hut the ftomach^ the fun6tion of which
requires to be exercifcd, produces during hunger
a general diforder, which becomes fatal if it con-
tinues. When the fenfation of hanger is not
called forth, life may be continued a very long
time without nouriOiment, as has been obferved
in perfons who remain in a ftate of abfjlute reft,
as hypochondriacs, maniacs, &c. The digeftive
fyftem then fufpends its fundions, like a limb
which is at reft; the fecretion of the fkin ftops ;
and the flight lofs of heat and pulmonary perfpi-
ration which takes place is fpeedily repaired, at
the expence of the infpired air, and of a fmall
quantity of drink.
When thirft is fuddenly excited by exceffive

lieat

ACTION OF DIGESTION. ~ 28$

lieat and abundant perfpiration, wben the animal
fluids have not that quantity of aqueous parts
which belongs to them, the fenfation experienced
is much more painful and more infupportable than
that of hunger.

Third produces a ftrong fenfation of drynefi,
of ardor, and of conftrid^ion in the fauces, with a
burning fever, and fooner proves fatal than hunger.
It is quenched with much more certainty by aci-
dulous or alcoholized beverages than by pure
water, even when iifed in a large quantity.

In forced marches, during very hot weather,
thirft mav be prevehted or allayed by moderate
and frequent dofes of alcoholized liquors, vvhicli
fupport the ftrcngth and excite the lecretion of k
greater quantity of faliva.

51. It has been obferved, that the hour of
fneals, the fmell of ragouts, the appearance of. a
covered table, or the noife of the diihes and the
mention of favory aliments, excite and put ia
play the gadric organs of gluttons and great eaters;
the falivary glands already enter into ad:ion j fe-
cretion commences, and their mouths begin to
water.

The aliments are firft cut and pounded by th<?
teeth, and at the fame time are penetrated by the
faliva, which flows in abundance, and the fecre*

'tiol^

28Q VITAL FUNCTIONS,

tion of which is maintained by the aS. of malli-'
cation, and by the favour of the alimentary fub-*
fiances.

It is of importance here to remark, that mafli-*
cation is effedled amidft a volume of atmofpheric
air, which is compreiled and mixed with the ali-
ments by the fides of the mouth ; the faliva by its
vifcidity is exceedingly proper for retaining a cer^
tain quantity of it, and the albumen which enters
into the compofitlon of the faliva abforbs alfo a
part of its oxygen, fo that the alimentary fub-
Hances are neceflarily mixed, during maftication,
with a certain portion of air j and when people
fwallow only their faliva it muft neceflarily carry
with it into the ftomach a very large quantity of
air.

The aliments, properly pounded by maftication,
and mixed with faliva and air, are afterwards col-
le6led into a ball by the a6lion of the tongue.
This alimentary bolus, comprefled by the lateral,
parts of the mouth and the upper fide of the
tongue againft the velum palati, is thrown back-
wards, and pafies through the narrow part of the
gullet, by pufhing the uvula againll the pofterior
aperture of the nofirils. When it reaches the
'hack part of the mouth, it experiences a- new
prefilire ; it is comprefi!ed by the pharynx, and by
acombine^ a^ion of the differeat mufcles of the

throat :

ACTION OF DIGESTION-. 28f "

throat: it defcends behind the larynx, lower-
ing the epiglottis, and pafles through the oefb-
phagus, from which it is conveyed into the fto-
mach.

The aliments when conveyed into the ftomach
ceafe to be rubje6l to the laws of chemical affi-
nity : they become entirely obedient to the vital
powers, and exhibit in their digeftion a very re-
markable feries of phcenomena.

By their prefence in the gaftric organ they a6i
as a particular irritant, which excites lecretion of
the digeflive juices, and produces a contra(5lion of
the ftomach ; fo that the gaftric juices, the preA
fure of the lides of the ftomach, the heat and
their refidence in a living organ, are the princi-
pal caufes which concur to transform the alimen-
tary fubftances into a homogeneous pulp, already
in fome meafure animalized.

Certain alimentary fubftances are more difficult
to be digefted than others ; and though different
ftomachs exhibit great variety in this refpec^, there
are fome aliments, fuch as fat, which are ge-
nerally of difficult digeftion. On this fubje6l
we muft refer to the curious experiments which
Gofie, of Geneva, made upon hi mfelf.

When an obftrudion takes place in the pylorus^^

' the aliments which pafs only with difficulty into

the duodenum, are often rejected by vomiting •

the calibre of the inteftines then decreafes, and

the

SSS TITAL PUNCTIOKS.

the fmall quantity of chymous matter, which flows
thither, is generally well digefted.

I have obferved, in the cafe of an obftraftion
of the pylorus with vomiting, that as long as the
intedines continue to perform their funftions,
the upper part only of the patient's body becomes
attenuated, while the lower half retains almoft its
ufual plumpnefs. On the other hand, we fre-
quently fee the lower parts of children, during
a long continued loofenefs, though the ftomach
digefts well, become conliderably wafled, while
the upper parts retain their ufual Hate. Thefe
two contrary obfervations are very remarkable in
the hiftory of digeftion.

The ftomach, after digefting the aliments it
contains, is no longer llimulated in fo lively a man-
ner by their prefence : its acflion then changes,
and inflead of that ftrong contra61ion which it
exercifed on them, it performs a regular motion
(the ferijialtic), which diredls them towards the
orifice of the pylorus, and makes them pafs into
the duodenum. This large and fhort inteftine,
affixed to the vertebral column only by a loofe
cellular tiffiie, and no ways fecured by the peri-
tonfeal membrane, is fufceptible of very great
extenfion : it may with great propriety be con-
lidered as a fecond fi;omach, in which is perform-,
ed a digeftive atStion, no lefs important than that
which takes place in the real ftojmach.

The

ACTION OF DIGESTION. 289

- ' 'The chymous matter, accumulated in the duor
denum, irritates this inteftine, which contrads and
■fecretes an abundance of digeilive juices.

The prefence of the alimentary fubliances in
the duodenum excites the adlion of the panc.reas,
as well as that of the liver; the produ6l of their
lecretion is efFufed in greater abundance in this
inteflinCj and being mixed with the aliments con-
tributes to complete digeftion.
. , Xhe fluid fecreted i^y the pancreas is entirely
fimilar to faliva.

The bile ought to be confidered as a parti-
cular excretion of the liver, which in being eva-
cuated ferves for digeftion, rather than as a fluid
fpecially produced for the fervice of that func-
tion.

The veflels which bring back the blood from
the ftomach, the epiploon, the inteflines, the mc-
fentery, the pancreas, and the fpleen, unite into^
three principal trunks (the great and Jmall fplenic and
the mef enteric), which are foon confounded into one
vein (the Juh -hepatic or 'Vena portce). This arterial
vein penetrates into the liver towards the middle
of its tranfverte fciffurej divides and fubdivides it-
felf there in an indefinite manner, and the blood
which it thus conveys to all the parts of that organ,
begins to afTume the qaaliuea necetlary for be-
coming again arterial blood : it fiees itfelf from a

VOL. m. u part

290 VITAL FUNCTIONS.

part of the hydrogen and carbon which are con-
tained in it.

The refult of this particular excretion is thfe
bile^ a fat fluid, which by its mixture with a fmall
quantity of foda forms a faponaceous liquor, eva-
cuated by peculiar veflels.

The liver, therefore, mufl: not be confidered as
peculiarly deftined to fecrete the bile, but as an
organ in which the blood begins to refume new
vital properties, by freeing itfelf from the fuper-
fluous matters it contains. How, indeed, is it
poffible to conceive that a moft voluminous organ,
which occupies a great part of the abdomen,
fhould be deftined merely for the fecretion of a
fluid, much lefs in quantity than that produced
by a kidney or by one of the breafts ?

This produft of excretion, however, is not
evacuated without contributing towards the or-
■ ganic fundions, and il becomes one of the moft
powerful inftruments of digeftion. The bile is
fo neccflary, that when it ceafes to flow digeftion
is completed with difficulty ; the chymous fub-
flance becomes dry, remains colourlefs, obftrudts
the inteftines, and an obflinate tenefmus takes
place.

The bile is formed by the venous blood which
returns from the greater part of the vifcera of the
abdomen; but as this blood does not circulate

with

ACTION OF DIGESTION. IQi

with great a(5livlty, and as its progrefs is checked
during different circumftances of digeftion, it ap-
' pears that the fpleen is deftincd to fupply the liver
Ipeedily with venous blood, which enfures the
fecretion of the bile.

Hence it is feen, that every thingin the or-
ganization is employed in an economical manner,-
and that no power is lofi:. The excretion of the?
bileferves for digeftion, as the excretion of the
Ikin for lowering the temperature by evaporation ;
and as air expelled from the lungs ferves for pro-
ducing voice, &c.

The biliary veflels decreafe in number, increafe
in fize, and at length unite into a du6l f:(be he-
patic), which proceeds towards the duodenum.
In its paflage, this du6l communicates with ano-
ther, called the cyjiic^ which proceeds into the
gall bladder, where the bile may be accumulated,
and remain a longer or a fhortcr time.

The prefence of the aliments in the duodenum
excites the a6lion of the liver, and even that of
the gall bladder ; the bile flows from the hepatic
du(?t and from the cyftic ; thefe two du61s termi-
nate at a common du6t (ihe duBus choledoclms)^
\vhich proceeds into the duodenum, two inches
from the pyloruF, and very near the apeiture oi
the pancreatic ^wS, : thefe two duels often unite,
and are confounded before they enter into the
duodenum.

u 2 The.

2.Q2 VITAL FUNCTIONS.

The chyfnous matter, prefTed by the fides of the
duodenum, penetrated by its juices, and moiften-
6d by the pancreatic liquor, and by the bile which
ftimulatcs that organ, acquires at length the ul-
timate degree of animalization, and forms a pulp
^vhich contains the chyle completely formed.

The alimentary fubftances, after this duodenal
Sigeflion, proceed flowly along the fmall intef-
tines by the perifialtic adlion o{ thefe parts. Dur-
ing this paffage, the digeflive a6l;ion continues
to operate ; and the chyle, which is feparated
from the reft of the chymous mafs, is abforbed by
the numerous open mouths of the chyliferous
veffels, with which the fur faces of thefe inteftines
are covered.

At length, the alimentary fubflanccs pafs into
the large inteftines ; the abforption of the chyle
and of the aqueous parts, which they contain,
continues to take plp.ce ; they acquire more con-
ftftence, are moulded into the form of the intef-
tines, and reach the rciflum, from which they
are afterwards protruded. This pfotrufion is ef-
fe6ted by the combined adiion of the fides of the
re6ium, and of the abdominal and diaphragma-
tical mufcles, which overcome the refiftance of the
iphin6ler, and expel thefe ufeltfs fx^ces.

52. The chyle, after being abforbed by the
mouths of the chyliferous ve(iels, foon proceeds

into

ACTION OF DIGESTION". 293

into the glands, where it ftill undergoes a peculiar
affimilation. It iflaes from thefe glands by larger
and lefs numerous veflels, which afterwards proceed
into a duel (the thoracic), fituated in the pofterior
part of the thorax, and communicating with the
left fub-clavian vein. This du(5l for the mod part
has a dilatation (refervoir of the chyle), at the
place where the lymphatic and chyliferous veflels
terminate. That on the right fide is much fmaller
than the one on the left.

It mufl: not be imagined that the whole pro-
duct of nutrition proceeds into the thoracic du6l :
this pafTage is very apparent, but there are a thou-
fand which efcape our eyes, and through which
the chyle may be conveyed to mix with the blood.
It is well knovi^n alfo, that nutrition is not inter-
rupted by a ligature of the thoracic du6l. This
du6l mufi: be confidered as the principal artery of
a limb, the lize of which is much lefs than that of
all the collateral arteries united.

53. Digefiion is one of thofc organic functions
which has the greateft refcmblance to a chemical
operation ; yet it differs eficntially from it in its
principal phienomena. Whatever, therefore, be
the nature of the alimentary fubftances employed^
whether thefe fubflances be vegetable or animal,
green, frefh, or in an advanced ftate of putre-
fadioUj boiled or raw^ dry or exceedingly fluid,

u 3 mixed

294 VITAL FUNCTIONS.

mixed with aqueous, acid, or alcoholic liquids ;
whether one fort of aliment or a great number
be ufed, and though -mixed in all proportions pof-
fible, they always give for refult, in a found and
"vigorous ftomach, a chymous fubftance, nearly of
the fame quality ; and in this fubftance the nature
of the aliments, which have concurred to produce
itj c^n no longer be known.

Digeltion, conlidcrcd under this eflential point
of view, has no refemblance to any of the knov^'n
phaenomena of chemiftry ; it is entirely owing to
the particular vital powers, and to that affimi-
lating power which is found only in organized
beings.

The operation of digeflion produces in the fto-
mach a very energetic centre of aftion, where all
the powers fcem to terminate. During this pro-
cefs, circulation and refpiration are increafed ;
and a very remarkable fliivering is experienced.
The other lyftems of organs remain then in a fort
of proftration, and exhibit great inaptitude for the
exercife of their Cundlions. Reft', therefore, is
the ftate moft proper to be in during this opera-
tion ; and it is that indeed which, on this occa-
iioo, all animals aftlime.

When ftomachic digeftion is nearly terminated
the fhivering ceafes, the pulfe becomes flower
and fuller, and a flight perfpiration takes place.
During the procefs of digeftion, the principal

phsenomena

ACTION OF DIGESTION, 2g5

phaenomena of a febrile paroxyfm are, ther^forcj,
obferved.

It is not merely in the gaflric organs and along
t|;^e inteftinal canal that digeftion may be efFe6led;
fubflances fufceptible of being digefted underga
that procefs in every part of the organization.

Thus, a portion of animal or vegetable matter,
introduced below the fkin, or into the fubftance
of the fleth, may be there digelled, and at length
entirely difappear ; air injefted into the cellular
tifTue, and liquids introduced into or effufed in
the cavities, may alfo be digefted and abforbed.
It is by a real digeftion that bloody, purulent, and
lymphatic colledlions, emphyfemala, different tu-
mours, and even calculi difappear. In all thefe
cafes, the a(51ion of the living liquids and of the af-
limilating power is every where obferved. The
organs make a continual effort to decompofe the
foreign fubftances with which they are in contact;
lince they abforb the materials fuited to them,
and reject the relt, either by the ufual paffages
of excretion, or by a feries of phlegmalic phe-
nomena.

It is probable, that when fubftances are reduced
to a very minute ilata the digeRion of them is
much eafier : thus it is well known, that but*,
chers who lead a life of repofe amidfl frefh meat
are in general fat and florid. The moleculas of
the animal fubftances, which evaporate^ are con-

u 4 ' veyed

296 VITAL FUNCTIONS.

veyed with the infpired air into the lungs, where
they experience an cafy digeftion.

We fhall have occafion more than once to fliow,
that a funsftion which is exclulively afcribed to
one 1} flem of organs, may be performed in feveral
other parts.

54. When digeftion is completely effecled in
vigorous gafiric organs, no difengagement, of gas
or development of acid or alkalies are obferved :
the aliments are completely digefted, without
emitting a putrid odour ; and the breath retains
its natural fweetnefs. But in a weak individual,
the gaftric fjtiem, being more or lefs debilitated,
does not perform its fundlions with the fame
energy. The aliments then, which are not en-
tirely fubjeQ:ed to the vital influence, are in the
fame flate as if they were enclofed in any other
place equally humid and warm ; and chemical
phjsnomena, more or lefs modified by the exifting
vital aftion, are obferved : hence there is a difen-
gagement of carbonic acid gas, of the gafeous
oxide of carbon, of fulphurated hydrogen, &c.
and a development of acid or alkaline matter.

Thefe phenomena are frequently obferved in
febrile difeafes, and in a peculiar manner in ady-
namic fevers^ attended with extreme profiration
of ftrength ; and when the powers are very much
cxbaufled. The aliments, left almofl entirely to

themfelves,

ACTION OF DIGESTION. ggf

themfelves, fpeedily become putrid, emitting an
odour fo infcflious, that this phaenomenon has
been confidered as an eflential lymptom and- a
caufe of thofe fevers, which have retained the
nanae o^ putrid; but this putrefaction is only a
natural confequence of the flate of debility to
which the gaftric organ is reduced, and of the re^
lidence of the aliments in a humid and warm
place.

55. Having.conlidered the aliments as a fub-
ftance proper for furnifhing a repairing produd:,
and having examined the principal phaenomena
by which the digeftion of them is charaderized,
it will be proper to examine them under a point
of view no lefs important, and to obferve what
is their a6lion, in general, on the whole nervous
fyftem.

The fubftances introduced into the ftomach al-
ways produce on the nerves of that organ an im-
preffion of contact, which may occafion a general
or peculiar change of fiiate, more or lefs appre-
ciable. Hence fubfiiances introduced into the
alimentary paflages, all aft as particular Simulants,
whether they be fufccptible of digeition or not.

In regard to their ftimulating action, the na-
ture of the aliments is not a matter of indiirer-
cnce ,to the organization. On the contrary, the
aliments produce confiderable changes in the

whole

ig9 VITAL FUNCTIONS,

whole lyftern, according to their peculiar quality,
independently of the quantity of nutritive parts
which they furoifh. What a difi^rence therefore
muft exift between people who feed on vegetable
fubftances and who drink water, and thofe whs
live upon flefli and who ufe fermented liquors I
The latter always poflefs more ftrength and more
energy.

It may be readily conceived that the action of
medicines is founded entirely on this property,
which foreign fubftances have, of producing a
change of Hate in the organization.

A great part of medicines are nothing but ali-
ments, the ftimulating aftion of which is more or
lefs energetic, as is the cafe with all medicinal
preparations extrafted from vegetable or animal
fubftances. Others are obtained from bodies little
fufccptible of being digefted, but which pofiels a
greater or lefs irritating aftion, as faline fubftances,
metallic oxides, &c. : in a word, fome nutritive
fubftances produce their medicinal efte£l only
when they cannot be digefted, as is the cafe with
manna, oils, &c. which purge merely by indigcf-^
tion : when the ftomach has fufficient power to
digefl: them, they no longer produce the fame
efFed.

Subftances introduced into the alimentary paf-
fages exercife their aftion in one general modej
ibat isj by ftimulating the nervous adion. This

ftimu»

ACTION or DIGESTION. 209

flimulating afliion is then varied, according to the
nature and dofe of the fubftance employed ; ac-
cording to the peculiar difpotition, habits, and
greater or lefs fenfibility of the gaftric lyflem, in
particular, and of the nervous fyflem, in general.

The caufe of the particular action of fubftances
on the nerves, which depends on their nature or
intimate compoiition, is entirely unknown; and
we are unacquainted with the relation which exifts
between the compoiition of a fubflance and its ac-
tion on our organs.

The a&ion of fubftances is fufceptible of varia-
tion according to the dofe. A glafs of wine gives
a very agreeable ftimulus to the whole iyftem, and
facilitates digeftion ; while feveral pints derange
entirely the nervous adlion.

The action of a fubftance is very different, ac-
cording as we are in a ftate of health or of difeaie,
and according to the nature of the derangement
with which we are afFedcd. Opium, which pro-
duces violent efFefts in moft acute difeates, though
admmiftered in fmall quantity, may be given in
very large dofes in tetanic afFedlions.
^ The habit which the gaftric lyftem contra6^s of
receiving the fame fubftances, greatly diminifhes
their a6lion, and people, by continued ufe, may
accuftom themfelves to the ftrongefi things.

The a6tion, which depends on the compoiition
of fubilances, ceafes in proportion as they are de-

compofed

500 VITAL FUNCTIONS,

compofed by the digeftive force of the ftorhach ;
and this a(5Jion is null when they are fpeedily di-
gefted : hence the reafon why a great number of
fubtlances, which produce a (Irong a6^ion on a
part deftitute of epidermis, exercife none on the
itomach .

In general, the refult of the a61ion of a fab-
ilance is conlidered as its primitive or dire6l ac-
tion. Hence it is faid that the warm water which
excites vomiting, and opium which produces an
agitation often very ftrong, weaken and debilitate;
becaufe the confecutive efFe6l of the firil ftimu-
lating action is to leave the organs in a fiate of
extreme debility.

The impreffion mj^de on the llomacb produces'
the fame teries of phsenomena, as if it were made
on any other organ : it oecations a change of ftatCj
for the moft part remarkable in the gaftric fj'flem,
fometimes more fhriking in a diftant organ, or
fenfible in the whole of the organization. Thus,
fome fubfiances exercife their principal action on
the ftomach itfelf, and favour its function ; of
this kind are alcoholized liquors : others manifeft
their acilion on particular organs, fuch as the kid-
neys, the Ikin, Sec. and on that account are faid
to have a fpecific a6tion ; fome alfo produce a de-
rangement in the whole of the parts, as is the
cafe' with thole which are poifonous.

From thefe general conii derations it may be
5 readily

ACTION OF DIGESTION. 301.

readily conceived how difficult it is to determine
the adlion of the different fubftances conveyed
into the ftomach, the -number of the caufes by
which it may be varied, and what opinion. ought
to be entertained, in general, of medical fuh^
fiances.

56. What relates to medical fubdances is an
€bje6l of too much importance not to engage our
attention for a fevv moments. Medicines, in ge-
neral, are ciafied according to the efifec^ which
they produce, and a great number even accord-
ing to that which they do not produce.

A man void of medical knowledge, who only
cafls his eye over the properties aferibed to medi-
cines in a Materia Meclica^ muft believe that the
medical art has attained to the higheil degree of
perfeclion ; fince it pofielTes remedies which ex-
ercifc an aftion in every manner poffible. But
thofe who have pradiifeci for tome time will ibon
be convinced, that the wonderful qualities of thefe
medicines very often exill only in the pompous
names with which they have been decorated. To
be convinced of this truth, nothing will be necef-
fary but to run over the claffification in fome of
the beft works on the Materia Medica, fuch as
that of Cullen.

This phyfician has arranged all the. medical
■fubiiances into twenty-GlaiTes, fome of which com-
prehend

ZOI VITAL FUNCTIONS.

prebend fubftances faid to a61 on tbe fluids, and
others on tbe foHds ; as if fabftances could afl
in any other manner than on tbe nerves and
organs.

I ft. The mdrittve, are common aliments, and
every thing that can be digefted is nutritive.

2d. The ajirlngent^ are particular ftimulants,
which produce a conftridtion of the parts to
which they are applied.

3d. Emollients, which eflentially are warm
aqueous fubftances. It cannot be faid that their
iirft a6lion is debilitating, fince the prefence of
warm water in the llomach excites vomiting or
occalions perfpiration j but when thefe fubflances
have exercifed an action for fome time, they pro-
duce a ftate of relaxation and of evident weak-
nefs.

4th. Slimulauts, are all thofe fubftances which,
when applied to the organs, exalt their ai5iion.

5th. Sedatives, are alfo ftimulants, which firft
produce a confiderable exaltation of the nervous
adlion, and exhauft or derange it to fuch a degree
as to bring on fleep. Of this kind arc opium,
wine in ftrong dofes, poifons, epidemic miafmata,
and cold.

6th. Antifpafmodics. Spafms being the confe-

quence of exalted nervous a61ion, every thing that

tends to put an end to that exaltation is antifpafmo-

dic. Exaltation of the nervous adlion, in any fyftem

7 ^^

ACTION OF DIGESTION. 303

of organs, Tiiay be deftroycd either by changing
that adion, or by producing a ftronger in fomfc
other part; and in all thefe cafes the antifpafmodics
muft be flimulants.

Bleeding is the beft antifpafmodic ; but it is
not a medicine.

7th and 8th. Attenuanfs and mfpijfayits, are me-
dicines fuppofed to have an exclulive adion on
the fluids, to give them more li<|uidity or confift-
ence. It is certain that drinking for a long time
•in profulion, or the contrary excefs, mull caufe
the conliftence of the fluids to vary ; but this
efFe<5t is only a very unimportant refult of the
ufe of liquid or folid medicines, the principal ac-
tion of which is exercifed on the nervous lyftem.

9th. Lenhnts mean nothing, and ought to be
confounded with emollients.

loth and nth. Anti-acids and anfi-aJkalks
produce the effedt afcribed to them, merely by
adling on the products of fecretion, and not on
the fecretory organs. Thus pure magnefia, con-
veyed into the ftomach when it contains acidities,
can combine with them and form a fait, which
afts afterwards as a flimulant. But the real anti-
acids and anti-alkalies are all thofe ftimulants pro-
per for reftoring to the organs the ftrength ne-
cefll^ry to enable them to perform their fun^lions
completely, and to prevent the development of
acid or alkaline productions.

12th.

304 VITAL- iFUNCTIONS.

■ iiXh. ^htifeptics. Septicity depends in ge-
neral on a vveaknefs of the vital aflion, which
permits the parts of our bodies to exhibit fome
phcenomena of decompofirion ; and it may ftill be
readily conceived that the only efficacious anti-
feptics are Xhejiimuhnts.

The lad eight clafles, denoted under the name

of errhines, Jialagogues^ expedorants, emetics, ca"

iharlicsy diuretics, diaphoretics y enienagogues, are

.merely ftimulants conveyed to a particular part, or

which exercife a fpecific a6lion on certain organs.

From this curfory view it is feen, that all thefa
twenty clafles of medicines may be reduced to
flimulants, the mode of a6iion of which is ex-
ceedmgly varied^ and fome of which indirectly
debilitate.

Though medicines are thus reduced to a ge-
neral a£tion, the choice of the moll proper reme-
dies in the different cafes of difeafe is never a
matter of indifference, and none but the fkilful
pra6litioner can determine properly in what man-
ner they ought to be employed.

57. To fum up in a few words the whole of
what has been faid, we muft confider, in the func-
tion of the gaftric apparatus, ift. The digef-
tive adion of the organs on the aliments: 2d.
The (limulating aclion of the aliments on the

organs.

In

ACTION- OP DIGESTION. 305

in regard to the digeftive aflion, we obferve
that the aliments are digefted by their mixture
with the fecretlons of the falivary glands ; of thofe
of the ftomach, of the inteftines, of the liver and
the pancreas, and by their relidencfe in a living
brgan.

When this funftion is completely difcharged^
it exhibits no analogy to chemical operations :
but when the ftomach begins to be weakened real
chemical phaenomena^ which refult from the fimul-'
taneous influence of the vital and of chemical ac-
tion, take place. The chyle contained in the
produ6l of digeftion is abforbed by the mouths of
the chyliferous veflels, and pafles into the glands,
where it undergoes an ultimate affimilatioh : it
then proceeds to niix with the blood through dif-
ferent pafTages, the moft remarkable of which is
the thoracic dud, coilneded with the left fub-
clavian vein.

In regard to the ftimulating aclion of the ali-
ments, feveral priucipar fads are obferved. The
aliments have a great influence ori the whole of
the organization ; and hence it happens that peo-
ple who feed upon flefli, and who life fermented
liquors, are much ftronger and more vigorous
than thofe who live' only on vegetable llibfl:ances^
and who drink nothing but water.

The whole adlion of medicines is founded
merely on the ftimulating property of the fab-

VOL, III. S ftans^

30(5 TITAL FUNCTIONS.

fiances conveyed into the alimentary pafTages *
this action continues until the fubftance is digefted j
or thrown out. *€!-

The Materia Medica poflefles ftimulants ex-
ceedingly various, fome of which indiredlly de-
bilitate.

ACTION

[ 307 ]

ACTION OF THE ORGANS OF CIRCU-
LATION AND RESPIRATION.

58. The blood, taken at Its departure from the
heart, is diftributed to ail the parts of the body
by means of the arteries, and returns by the veins,
to the right fid^ of that organ. To be conveyed
then from the right to the left fide of the heart, it
diftributes itfelf entirely to the lungs.

In this manner the blood continually performs
a double circulation ; namely, a general circulation
in all the parts of the body, and a particular cir-
culation in the pulmonary organs.

We (hall examine the pheenomena it exhibits
in this progrefs.

59. The blood returns from the lungs by four
veins, which proceed into the left auricle of the
heart ; this auricle, by its contra6lion, drives it in.
part into the ventricle on the fame lide, and this |
ventricle forces it into the aorta. The blood can-
not return from the ventricle to the auricle on
account of a valve (the mUral) which oppofes it;
and it cannot flow back from the aorta to the ven-
tricle, becaufe it is ftill prevented by the iygmoid
valves,

X 2 The.

3(58 VITAL FUNCTIONS.

The blood which returns from the lungs is of
a beautiful fcarlet red colour; it is florid, fpumous,
Ibniewhat warmer than the venous blood, and
therefore exhibi.ts all the charaiflers of arterial
blood. Being continually expelled from the ven-
tricle and the aorta, by the adtion of the auricle,
it is diftnbuted to every part of the body, where
its circulation is continued by the contra6lion of
the arteries through which it pafles.

The contra<5^ile force of the heart and of the
arteries is maintained by the nervous a61ion of
thefe organs, and by the prefence of the blood
which flows thither.

The force with which the heart contrafls has
never been eftimated in a fatisfa6lory manner.

The movements of the arteries are ifochronous
with thofe of the heart ; thefe movements feem to
be inflantaneoufly tranfmitted by the fluid of the
blood.

The beats of the heart and of the arteries are,
owing to alternate movements of dilatation (dia-
JloJe), and of contra61ion (Jvfiole).

The motion of diaftole feems to arife not only
from the development of the tides of the arteries,
but alfo from a flight difplacement of thefe
veflels. -

The motion of the heart and arteries is per-
formed with fo great velocity, that in adults they
make about 80 pulfations in a minute. This

number

CIRCULATION AND RESPIRATION. 30Q

nurabep varies afterwards at the different periods
of life, and in the date of difeafe. During the firli
years of lifcj the pulfe beats- 130 and 140 times
in.a minute; but this number decreafes with age;,
and in old perfons it fcarcely gives 60 beats. In
difeafes, when the whole body is affected, ' it may
be readily conceived ^ that the nervous a6lion of
the iyftem of circulation muft be deranged, and
that this derangement manifefts itfelf in the ftate
of the pulfation.

The pulfe, in general, exhibits the fame cha-
racter in the fame afFeCiions, and may ferve as ah
indication of them to the phylician, who has been
long habituated to this kind of obfervation. But
the advantages derived from confulting the pulfe,
in difeafes, has certainly been much exaggerated.
The arteries, in diftributing themfelves to every
part of the body, ar© divided and fubdivided in
an indefinite manner, exhibiting frequent anafto-^
mofes.

The fum of the fmall arteries is always m_uch
fuperior in capacity to the aperture of the trunk
which furnifhes them ; fb that the circulation
mufl be lefs rapid in the rarni than in the ar-
terial trunks.

If the courfe of the arteries be traced out, they
will always be feen to furnifh fubdiviiions ; the
blood gradually feems to lofe its red colour, and
nothing is obferved, but white veflels of the ut-

X 3 vnoi\

310 VITAL FUNCTIONS.

moft tenuity, which at laft efcape the eye, even
when aflifled by the beft microfcope ; fo that the
mode of termination of the arteries is Itill un-
known.

It is proper here to remark, that animalcula,
,the fize of which does not exceed the three or
four hundredth part of a line, may be diftindtly
ifeen by the microfcope. Thefe animalcula, which
increafe, feed, and propagate, have in all probabi-
lity veflels, the fubdiviiion of which is very great.

If we fuppofe that each point of our body ex-
hibits an organization equally perfect, and as com-
plex as that of thefe animalcula, which is confirm-
ed by microfcopical obfervation, we fhall then be
enabled to form fome opinion refped^ing the ter-
mination of the arteries ; the fubdiviiion of their
capillary tubes ; and the ftate of divifion in which
the blood mull be when it attains to that point.

From various obfervations, however, there feems
to be reafon for believing, that the arteries unite
diredlly with the veins, and that the termination
of the one is confounded with the origin of the
other. What feems to be certain is, that the ar-
terial blood may eafily pafs into the veins, and it
proceeds thither with more eafe according as the
life is lefs adive. ThuS, when blood is drawn
from an animal by an aperture made in a vein, this
fluid iffues, at firft, with all its charaders c-' venous
blood ; but in proportioa as the animal becomes

weaker.

CIRCULATION AND RESPIRATION. 311

weaker, the blood gradually aflumes the arterial
charadler, and feems at length to pafs from the
arteries into the veins, without having undergone
any change.

But, however this may be, it is in the interval
between the period when the blood efcapes oiir
eyes through the arteries, and that when we begin
to fee it return by the veins and the lymphatic
veflels, that the mod important phaenomena of
life take place. It is during this infinitely fmall
fpace, that- the different changes, continually
going on in every part of the organization, are
effedted.

The arterial blood, which is in a Hate of ex-
treme divifion, reduced to vapour diiiclved in ca-
loric, exhibits in this manner materials proper for
all the fecretions.

If the nerves continue to diflribute to the or-
gans the principle of adion, neceflary for the ex-
ercife of their fun6tions, the phaenomena of life
may then be completely performed, and in differ-
ent manners,- according to the particular flrudlare
of each organ of fecretion. Thus the faliva is
lecreted in the falivary glands, the milk in the
breafts, the urine in the kidneys, the fluids at the
furface of the ferous and mucous membranes, the
fat in the cellular tifTue of all the parts : it is pro-
bable allb, that the fluid which circulates in the
■.::v;:-;-i '';. • X4 nerves.

$it VITAL FUNCTIONS.

nerves, and which conveys every where Hfe an4
fenlation, is fecreted in the brain ; and hence the
vafcular and nervous fyftems are continually in a
ilate of mutual dependence.

The blood contains none of thefe produ6ls
completely formed ; but it prefents materials pro-
per for eompoiing them.

When the arterial blood is difiiribated to an or-
gan, the fun6iion of which is active, it undergoes
very ftriking changes, and returns to the fiate of
venous blood and of lymph ; but if the nervous
a6lion on this organ be fo weak that it does not
properly difcharge its function, the blood then
pafTcs from the arteries, into the veins, almoit
without having undergone any changes.

It is well known that all the organs are com-
pofed of a tilTne of veifels and nerves differently
arranged, and in the interfaces of which are depo=
fited fubftances of different natures and denfities,
and that the veflels and nerves themfelves exhibit
the fame compofition.

The iiiollecuiss of matter, which compofe all
thefe organic tiffoes, are continually experiencing
changes : one part are inceffantly removed, and
their place is fupplied by others^ which gradually
afiiime a different arrangement. During thefe
continual changes, the repairing molleculse in-
creafe always in denlitj and number ; fo that the

organs
5 .

CIRCULATION AND RESPIRATION-. 31$

©rgans gradually lole. their pliablenefs andytheir
mobility, which in the courle of time neceflarily
becomes a caufe of death.

60. Amidft the continual changes which ia%^
place in every part of the organization, it mufl be
oblerved that the fubllances excreted exhibit, in
general, a greater denfity than that of the materials
which ferved Xo produce them ; or, in other words,
that the fubflances which iflue from our bodies
have more confiflence than thofe which enter
them.

Thus we are continually lofing by pulmonary
and cutaneous perfpiration, by urine and the other
particular excretions ; and thefe lofles are repaired
by the organs of digeilion and refpiration.

The materials which efcape by the different
paflages are, in general, carbonic acid gas (the
heavieft of all. the gafes) ; liquids charged with
falts, acids, albumen, gelatin, &c. and fat fub-
llances.

The materials abforbed are: in the lungs, oxy-
gen, and probably a little azote ; in the gaflric
fyftem, the chyle, the product of digeft ion properly
fo called, a great deal of water in the ftate of va-
pour, and confequently very pure, and probably
air alfo introduced into the ftomach.

But it is evident that, lince the fubflances ab-
forbed

314 VITAL FUNCTIONS.

ibrbed have much lefs denfity than thofe excreted,
there muft be a difengagement from them of ca-
loric ; and this difengagement is the caufe of ani-
mal heat.

Thus the heat difengaged from the different
parts is a refult of the changes of denfity which
the fluids continually experience in the different
fecretions.

The quantity of caloric difengaged is in the ratio
of the adivity of the organic funftions ; and this
activity depends on the intenlity of the vital force,
©r nervous aftion, to vi^hich all the phsenomena of
the organization may be referred.

The nervous a6lion of the organs of fecretion is
maintained or excited by all flimalants, and even
hy the exercife of their fundions.

When an organ is ftrongly excited, it becomes
St centre of adlion ; the blood flows thither in abun-
dance, and fecretion is ef?'e(?tcd with great a6livity.
When the organs of fecretion are not thus excited,
or put into a6iion, their functions flag and may
©ven ceafe entirely.

6i. The blood, after being diftributed to every
part, and after having furnifhed to each point of
the oganiz^ation the materials neceffary for its par-
ticular fecretion, returns by two orders of veflels,
the veins and the lymphatics.

The

CIRCULATION AND RESPIRATION. 315

The veins bring back all that part of the blood
which has undergone the leaft change: that which
retains a red colour.

The lymphatics colle6l the products of all the
feroiis fecretions, which are continually renewed,
and all the aqueous parts, which hold in folutioa
or in lufpenfion the remains refulting from the
continual changes efFe6led in all the organs.

The vemSj at firA exceedingly fmall, foon unite
to form more apparent ones, and thefe continue to
join, exhibiting frequent anaftomofes. The ra-
raufculi by their union form rami, the rami
branches, aod the branches trunks, which termi-
nate in two large veins. One brings back the
blood from inferior parts of the body (the vena
cava inferior J, the other brings back that from the
upper part (vena cava fuperior), and both proceed
into the right auricle of the heat.

The veins, as they unite, always decreafe a little
in lize ; {o that the diameter of a venous trunk is
always fmaller than that of the rami which con-
curred to produce it. By this difpofition, the
blood muft circulate quicker in the trunks than in
the branches.

The veins, at certain diftances, are furnifhed
with valves, formed by folds of their interior tunic:
thefe valves are generally difpofed in pairs ; they
prevent the return of the blood, and interrupt the
continuity of the fluid in thefe veflels.

7 Th«

Sl6 VITAL FUNCTIONS.

The veins which bring back the blood from any
jpart, are ahvays more numerous and of a larger
fize than the arteries which carried it thither; an4
this necefTarily renders the- venous circulation
ipuch flower than the arterial.

The blood circulates in the veins by the con-
traftile force of their fides, affifted by the tonic
a6lion of all the neighbouring parts. This circu-
lation is maintained by the nervous a6tion of the
veins, and by the prefence of the blood which
Sows. into their cavities.

The lymphatic veflels, much more numerous
and fma.ller than the veins, are difperfed in abun-
dance throughout all the parts, and particularly in
the white organs, of vi'hich they feem to form the.
whole tiiTue. They abforb the ferous liquids con-
tinually fecreted in the different parts.

The lymphatics, by their numerous diflribution,
form an inextricable fort of reticulation: they
unite like the veins to form larger and lefs numer-
ous veflels. Like the veins, they are provided with
valvular folds, generally difpofed in pairs, which
oppofe the return of the lymph.

After a certain pafTage, the lymphatics proceed
into the glands, the aggregate of which forms an
effential part of the abforbing 1}' Item.

Thefe glands are fmall, round,^ or ovoid bodies,
reddifhj arranged in groupes, and which have the.
appearance of grains or feeds united. The lym-
phatic

CIRCULATION AND RESJIRATION. 3 if

pliatic glands are obfervcd, in particular, in the
bend of the great articulations, on the mefentery,
and along the large blood veffeis.

The lymphatics which proceed to thefe gland's
lofe themfelves in their fubftance. The lyraph-
vvhich they carry thither undergoes a particular
kind of affimilation ; it then begins to refuma
thofe charaders of animalization which it feemed
to have left, and iiTues from them by another
order of veflels, lefs numerous and larger.

The lymphatics' thus continue to advance to-
wards the thoracic du6l, uniting to Yorm larger
veflels, and traverfing the glands which they meet
with.

All the lymphatic veffeis proceed, in this man-
ner, to the thoracic .dud:. Thofe which come
from the lower part of the body proceed into the
abdomen^ unite with the chyliferous velTels, and
proceed together to the lower part of the thoracic
dudt. in this place, which is fituated near to the
upper part of the abaomen, this du<Sl often exhi-
bits a dilatation, more or lefs flrikiijg (refervoir of
the chyle): it then traverfesthe diaphragm with the
aorta, and afcends on the right lide of that artery,
as far as the fummit of the thorax ; it then runs on
the left, pailing before tke vertebral column, and
proceeds into the left fubclavian vein.

The lymphatics which come from the upper
part of the body proceed fo different points of the

thoracic

318 VITAL FUNCTIONS.

thoracic du6l, near Its inferlion into the fub-cla-
vian vein. .

A thoracic dti6l is frequently found on the
right fide, but much fmaller than that on the left,
and formed by the union of the lymphatics, which
come from the upper part of the right fide of the
body.

Circulation feems to be performed very flowly
in the lymphatics ; and this fyftem, without doubt,
is that which fhows the lead a6livity in its func-
tions : the pafiage of the lymph through the glands
contributes a great deal to check its progrefs.

The ufe of the lymphatic fyfiem evidently is to
bring again into circulation the ^efidue of all the
fecretions, after making them undergo a particular
afiimilation or fort of digeftion.

This important funiSlion is performed flowly
and without interruption ; and is maintained by
the aftion of the nerves, which are diftributed to
the lymphatics and their glands, and by the pre-
fence of the fluids abforbed and brought into cir-
culation.

' When the nervous action of this fyftem is dimi-
nifhed, its fundion is checked ; and the ferous
fluids, being no longer properly abforbed, remain
in the large cavities or in all the tifllies, which
gives rife to dropfies of different kinds and to
anafarca.

Phyficians believed that they had found in the

difcovery

CIRCULATION AND RESPIRATION. 31^

difcovery of the lymphatic veflels an explanation
of a great number of the phcenomena of difeafe ;
and they began to make a falfe application of thii
knowledge, as is the cafe rwith almoft every new
difcovery.

It was to the humorifl phyficians, in particular,
that this difcovery feemed to be of the greateft
utility. As they afcribed almotl all difeafes to hu-
mours circulating in the fluids, they faw in the
lymphatic fyftem a convenient way of conveying
them to every part of the body, and of making
them proceed with rapidity from one place to
another.

As the lymphatic fyftem abforbs the fluids ef-
fufed in every point of the organization, they ima-
gined that it ought to abforb alfo all thofe foreign
fubftances fubje6ted to its a6lion ; and that it con-
veyed them to different parts to produce in them
accidents more or lefs fevere, or that it poured
them into the blood to infe3 its whole mafs.

But all thefe fuppolitions were mere conjedlures,
fupported by no real proofs, and contrary to the
progrefs of that function and to the common ,
phsenomena of life.

It has never been proved, by any dire^ experi-
ment, that foreign fubftances can be taken up by
the lymphatic veflels and conveyed to diftant parts.
The experiments made on purpofe to afcertein the
-f * af bfT'-o} ^sd ^r-^d+tedt b^^^'.^hrf sokIc truth

i2"f^ VITAL FUNCTIONS.

Htruth of this fad prove^ in an evident manner, thS
contrary.

Thus Dupuytren, in his ingenious experiments
on the chyle> tried, but without fuccefs, to pro-
duce an alteration in that fluid. He caufed dogs
to fwallovv animal, vegetable, and mineral fub-
ftances of every kind, which he thought likely td
ieffedl changes in the quality of the chyle ; but he
was never able to alter, in a ienfible manner, its
tiature, its colour, or its odour. The gailric or-
gans, by their vital energy, bppofe all thefe altera-
tions: thiey digeft every thing fufceptible of di-
geftion J ahforb what is proper for them, and rejedl
what might prove hurtful to thiem.

The cafe is the fame with the lymphatic fyfteni
of all the parts of the body. The foreign fubftances
introduced beneath the fkin, or conveyed into thia^
fubllance of the organs, are not abforbed, without
being digeiied and reduced to principles fufcepti-
ble of entering into circulation ; and fubftance^
taken up by the lymphatics, after this firft digeA
tion, do not pafs into the venous blood until they
have undergone a fecond aflimilation in the lym-
phatic glands.

But the nerves of the different parts cannot
withdraw themfelves from the impreffion of thei
foreign bodies which come in contact with them=
This impreffion may change the mode of a(5iion

of

CIRCULATION AND RESPIRATION. 321

bf the part, and produce a local pblegmaiiaj or
he propagated as far as the cerebral centre, and
give rife to general •demngements, more or lefs
ferious, and which are afcribed to circulating hu-
mours,

6i, We have already fhovvn that the arterial
blood proceeds from the left fide of the heart to
diflribute itfelf to every part of the body, and to
carry thither the materials for the different fecre-
tions; and that it returns by the veins, ta the
right fide of that organ, from which it pafles tO/
its left fide by traverfing the lungs.

The arterial blood maiiitains itfelf always at the
fame temperature^ and at the fame degree of flu-
idity, by means of perfpiration, and the fecretion
0:f the urine; andlhus frees itfelf from the heat
and water which it receives in excefs.

The blood, which returns-by the veins, refumes
the qualities of arterial bloody chiefly during its
paflage through the liver and the iungs.

We fhall here examine more minutely thefe
important pbcenomena.

6;j^. The heat bf the blood is maintained by the
continual fecretions which take place in every part
iof the organization.

As the produ6is of the different fecretions have
always more denfity than the materials which

TOL. Ill, T f^rved

322 VITAL JUNCTIONS.

ferved towards their formation, the refult muft ne-
ceflarily be a continual difengagement of heat.
This difengagement of heat is proportioned to the
adivity of the fecretory functions : it is exceed-
ingly weak when thefe funclions are performed in
a flow, manner; and Itrong when they take place
with great energy. A woman who iifes little ex-
ercife, and only a very froall quantity of food, has
always a cool dry fkin, and the greateft lofs of heat
is fuftained by pulmonary perfpiration. On the
other hand, a man employed in fevere labours,
and who eats a great deal, has the Ikin humid and
warm ; and an abundant perfpiration continually
carries off a large quantity of his caloric.

Thus animal heat is one of the pr6du6is of fe-
cretion; its excefs read:s on the organs as a fiimu-
lant ; and excites, in a particular manner, fecre-
tion and fweat. The evaporation of this fluid,
fecreted in excefs, carries off from the furface of
the body a great quantity of caloric, and by thefe
means the temperature is lowered.

In proportion as the temperature of the body is
lowered, neither fecretion nor fweat are fo power-
fully excited, and the lofs of heat ceafes to be to
great. It is by this organic regulator, that animal
heat is always maintained nearly at the fame tem-
perature of 40 degrees of the centigrade thermo-
meter (104° Fahr.)

In local phlegmaiise, when a thorn, for example,

has

CIRCULATION AND RESPIRATION. 323

has been introduced beneath the fkin, the nervous
adiion of the part is violently excited; circulation'
is accelerated ; the fecretions take place v;ith more
intenlity^ and the local heat is fenfibly increafed.
But this augmentation of heat never extends be-
yond two degrees, and if its intenfity appears to
be greater, during the burning ardour which is
experienced, this painful fenfation ought to be
afcribed, in a great meafure, to the too ftrong
nervous excitement, and to the derangement in
the habitual order of the fundions of the injured
part.

Belides thelofs of caloric, difengaged by perfpi-
ration, the body habitually lofes a great quantity
of fluids by the ikin and the lungs. The fum of
the fubftances which efcape by thefe two ways
^exceeds the half of the weight of the whole ali-
ments ; and pulmonary perfpiration is equal to
that which takes place by the Ikin.

The product of an abundant perfpiration is
much more aqueous than that of the habitual per-
fpiration, called infenfible : the latter is clammy
and greafy, and affedls a peculiar odour, which
varies in the different parts in the two fexes, and
even in diflerent individuals.

Heat and labour greatly increafe this excretion ;
cold and reft can entirely fufpend it.

The fecretion of fweat and that of urine feem
mutually to fupply each other's places and the

y 3, adtivity

324- VITAL FUNCTIONS.

acclivity of their fundions is always in the inverfe
ratio of each other. When fecretion of urine is.
impeded, an analogous excretion takes place by
the Ikin, and the fweat afTurxies a urinary cha-
ra6ler.

64'. The arterial blood throws out the quantity
of aqueous parts, which it receives in excels,
chiefly by the urinary pafTages.

A raan, daring the whole day, may do nothing
but drink and void urine ; and it is inconceivable
what a large quantity of liquid may be thus made
to pafs through the body in a given time.

That a perfon may be able to drink a large
quantity, without being injured, the water muil
contain ftimulating fubllances, fuch as alcohol or
acids ; thefe beverages then folicit the organs to
diffeil them, and at the fame time excite the kid-
neys to feparate from the blood a quantity of wa-
ter, proportioned to that which has been drunk.

If the beverage is nrierely aqueous^ and if taken
in too great abundance, the gaftric and urinary
lyftems are not properly Simulated ; the beverage
is digefied only with extreme difficulty, or cannot
be (o completely 1 and, in this cale, a vomiting-
takes -place, or even indigeilion, which is often
very dangerous.

This important conxideration ought never to be
loll fight of in difeafes, in which it is neceflary to

avoid

CIRCULATION AND RESPIRATION. 325

avoid overchar^incf the weak and debilitated fto-
mach with aqueous beverages. In this point of
view the abufe of ptifans is much greater than is
imagined.

Fermented liquors are neceflliry to men who
feed on coarfe aliments^ with Httle or no feafoning,
becaufe it is always requifite that the ftomach
fhould be properly ftimulated, either by -the drink
or the food. But when the aliments are llrongly
feafoned by the ftimulating produdions of warm
countries, there is not much need for alcoholized
liquors ; and people will fufFer much lefs inconve-
nience by abftaining from them entirely, than by
contrading the habit of ufing them to excefs.

The need of fermented liquors is felt in a much
fironger manner in warm and cold countries,
where the organization is continually ftruggling
againft the temperature, than in the moderate
climates.

The arteries which proceed to the kidneys are
very large ; it has been eflimated that their capa-
city is fuch as to afford a paffage to the eighth
part of the blood.

The quantity of urine feparated in a given
time, and' the fpeed with which it is fecreted in
confequence of drink received into the ftomach,
has induced fome to believe that there may exift a
more direft mode of conveyance, than that by the
blood, for tranfmitting liquors from, the gaftric

y 3 organs

326 VITAL FUNCTIONS.

organs to the bladder, and this funftion has been
afcribed alfo to the lymphatic velTels; but this af-
fertion is unfupported by proofs, and it is from not
properly nnderftanding the limultaneous adlion of
feveral organs, in confequence of the fame ftimu-
lant, that it has been thought necelTary to recur
to this hypothefis. '

The urine fometimes afTumes a colour analo-
gous to that of certain fubftances received into
the flomach; it has been fuppofed that this colour
ariles from the prefence of thefe fubftances con-
veyed^nto the blood, and tranfmitted thence to
the urinary fyftem : thus the urine becomes fome-
times red by the ufe of beet-root ; yellow by that
of faffron or jalap, but without containing any of
thefe fubftances ; for urine coloured yellow by the
a6lion of faffron has not the leaft fmell of the fta-
mina of that plant.

If the urine fometimes aftiimes the colour of
certain aliments or medicines, it often exhibits one
very different : thus it becomes green by tama-
rinds, blackithor puriform by oil of fweet almonds.
Sec. If an aliment or medicine could communi-
cate to urine a part of its fubftance, it woulcl
doubtlefs be its odorous molecule j which, as ap-
pears, ought to penetrate every where with great
facility ; but this is never obferved to be the cafe,
Thus afparagus, which has an agreeable odour,
occaftons a very fetid fmell in the urine; and tur-

pentinca

CIRCULATION AND RESPtRATION. 357

pentine^ the odour of which Js, very. penetrating,
gives to urine the fvveet ,and agreeable. odQUT of
violets.

' In all thefe cafes, the changes which take place
in the urine are the relult of a new mode of acr
tion, con)fnunicatcrl to the renal fyftem. -There
is no organ of fecretion, the product of which may
not be changed, when a new mode of a6lion is
thus excited in it; and it is well known how va-
rious the fecretion of the mucous membranes is in
catarrhal affedlions, and what a dreadful chara6ier
the faliva afllimes in the hydrophobia.

Hence the changes which take place in the
urine, in confequence of certain fubflances being
digefted, do not arite from thefe fubftances having
palled into the urine in their naturaL flate, but
from the fpecinc adlion which they particularly
exercife 6n the kidneys, which changes their habir-
tual mode of a6lion, and alters the ufual product of
their fecretion, •

It is chiefly in acute difeafes that the urine ex-
hibits characters highly varied. Every time that
the organization experiences a general derange-
ment, the kidneys are afFefted in a manner pecu-
liar to th'emfelves. Their mode of fecretion is
changed ; and the urine aflTumes a particular cha-
rafber, which may be indefinitely varied.^ vAkLjiA
^ Urine vari^^ in particulary- iar^g^f^ilo -C[uan-

32S VITAL FUNCTIONS.

tity, according as the a6lIon of the kidneys is in-
creaied or diminished.

The numerous changes of colour, confidence,
and fmell, and the varied fediment which urine
exhibits in difeafeSj have induced the vulgar to
believe that the infpe6lion of it may be, of great
utility in medical pra6iice ; and there have even
been phyficians who confulted the urine of their
patients.

Changes in the nature and quantity of the
urine only announce that there has been a change
of adlion in the kidneys.

The urine generally ailumes the fame charac-
ters in iirailar aftedlions; and the infpe6iion of it
may then affill the prognofis. But unlcfs the
phyfician be a good chemiil, and examine it by re-
agents, it will be impoffible, in fuch cafes^ to de-
rive from it mud^h benefit of importance.

There is one particular affoShn of the kidneys,
in which thefe organs rapidly fecrete an exceflive
quantity of urine (diaheUsJ. All the nutritive juices
are confumed in this way ; and the patient be-
comes weakened as by a diarrhoea. This affe6lion
does not arife from a relaxation of the kidneys, as
is generally believed ; for an organ relaxed or de-
bilitated does not perform its funfbions with more
energy ; but it arifes from an increafed a'dlion^ a
continued irritation in thefe organs^

Urine.

CIRCULATION AND RESPIRATION. B1§

Urine, by treeing the blood from a quantity of
aqiieoiis part^. which it contains in excefs, takes
from it aifo a great deal of other principles. The
ilf>w of urinCj however, rnufl not be confidered as
a Uxiviation, during which acid, faline, and earthy
llibftances are carried off; but rather as a real le-
c^etion, a peculiar organic operation, during which
the greater part ofthe fubftances found, in urine
are formed. Thus uric acid, the prefence of which
forms the principal charafter of urine, is not found
in the blood, but has been formed in the kidneys.

In proportion as the urine is fecreted in the
tifTue of the kidneys, it exudes from the mam-
inellous tubercles rnto the calices, by which they
are enveloped: it is thence colle6led into fmall
bafons, from which it flows along the ureter, and
is thus conveyed into the bladder.

The urine colledted in the bladder gradually
diftends it. When this organ has acquired a cer-
tain degree of tenfion, it contrails ; and by the
iimultaneous adion of its fides and of the mufcles
of the abdomen and of the diaphragm, the refift-
anceof its neck is overcome, and the urine is ck-
pelled with more or lefs force.

The bladder has been called the animal cham-
ber-pot : it miift not be imagined that the urine
remains there as in a veffel ; it is fubjeded to the
continual aftipn of the fides which contain it; thefe
iides make an effort to digefl: it, and incefTantly

abforb

330 TITAL JUNCTIONS.

zMorh its aqueous parts, on which account the
urine in the morning is much thicker and more
charged than when voided a httle time after it has
arrived in that organ. In regard to the unne of
drink, of digeftion, and of the blood, it may be
readily conceived how erroneous ail thefe diftinc-
tions are : there is only one kind of urine, that of
the kidneys,

65. The arterial blood, in its circulation, dif-
tributes itfelf to the organs of motion, to thofe of
the fenfes and of fecretion, and carries thither the
materials proper for the changes continually efFed,-
ed in all thefe parts. But it diftributes hfelf alfo
to fome organs, with the ufe of which we are not
yet acquainted : of this kind are the thyroid gland,
the thymus, and the fpleen.

The thyroid gland, larger and of a darker co-
lour in children than in adults, in the female
than in the male, is fituated in the middle part of
the neck, before the bottom of the larynx. It
feems to be compofed of an afleinblage of lobes,
divided into lobules : in the interior part it exhi-
bits fmall veficles, which contain a yellow vifcous
fiuid. It is a fwelling of this gland that produces
the goitre. This afFedion, peculiar to women of
certain countries^ is the refult of caufes hitherto
unknown.

The thymus is a glandalous body^ fituated be-
hind

CIRCULATION AND RESPIRATION. 33t

bind the fternum, between the two laminae of
the pleura. It is of a large fize, flabby, arid of
a pale yellow colour in the fcetus ; it decreafes,
affiimes more conflftence, and acquires a darker
colour with age ; and in old age difappears entirely.

In the foetus, the thymus, compofed of two
lobes divided into lobules, exhibits in the infide
an albuminous, whitifh fluid, and has no apparent
excretory dudls.

The fpleen, fituated in the left hypochondrium,
is of a foft confiftence, x^ellular, and has a blueifli
red colour : it receives a very large artery of the
coeliac trunk.

The arterial blood, after diftributing itfelf to
every part of that organ, returns by veins which^
by their union, forms a trunk that proceeds into
the liver. Hence it appears that* the ufe of the
fpleen is to give its blood to the liver, after it has
undergone a change, which renders it analogous
to the venal blood.

66, The blood, after being diftributed to every
point of the organization, and having thus dif-
charged the fundlions peculiar to it, returns from
all thefe points, in the ftate of venous blood and
lymph, to repair its lofl!es ; to refume again the
qualities of arterial blood, and to be fitted to ferve
for a new dillribution.

The lofles which th^ venous blood has fuflained,

during

$S% Vital functions.

daring its diftributionj are repaired by the pro-
duct of digeftion.

The chyle and the lymph, before they mix
wfth the venous blood, begin to experience
changes in their paiTage through the lymphatic
glands ; thefe fluids undergo a peculiar affimila-
tion, and again acquire charadlers of animaliza-
tion, which render them proper to form confti-
tuent parts of the organic fubftances.

The venous blood fcems to return to the fcaie
of arterial blood, by freeing itfelf from fome fub-
flaoces and by taking up others.

In its pafTage into the liver and the lungs it
abandons thofe materials, by which it is conftituted
venous blood, and abforbs new principles in the
refpiratory organ.

A part of the' venous blood, before it returns to
the right tide of the heart, patles through the
Jiver. Thus the veins, which bring back the blood
froni the ftomach, the inteftines, the epiploon,
the mefentery, the pancreas, and the fpleen,
unite into two trunks f^he fplenic and mefera'ic),
which are foon confounded into one vein (thefiih-
hepatic or vena-port^). This arterial vein, which
is very largej penetrates into the liver tovt'ards the
Biiddle of its tranfverfe fcifTure ; the blood, which
it .carries thither, is diftributed to every part of
that voluminous organ, and difappears in the very
fine divifions of the capillary ramufculi.

- The

CIKCULATION AND R.ESPIRATION. 03$.

The venous blood, which travedes the vifcera
and the. abdomen, and particularly the mefentery
and the epiploon, is overcharged with> a great
deal of fat parts, from which it feems to be freed
chiefly in the fecretion of the liver. The liver by
its a^iion fecretes the bile, wliich is evacuated by
a peculiar order of velTels ; and which procee^ls
into the duodenum, where it becomes one of th®
moil powerful agents of digefticn.

In the fecretion of the bile, the blood is rie-
cefTarily freed from the hydrogen and carbon of
which that uncliious humour is corapofed; and
by thefe means is difpofed for refiwning the quali-
ties of arterial blood.

It is of fo much importance to the organic order
that the blood {hould free itfelf from the princi-
ples which form the bile, that when the fecretion
of this fluid cannot take place in the liver, in con-
fequence of fome peculiar affcclion of this organ,
it appears that it is produced in other diftant parts.
Thus in the jaundice an analogous fecretion of
bile takes place in the kidneys, in the cellular
tifliie, and in the flcin.

It is not, therefore, for the parpofe of digef-
tion alone that the bile is produced ; becaufe
when it cannot be feparated in the liver it is fe-
cretcd fomewhere elfe. In this cafe, the efl^ntial
phasnomenon always takes place j the blood aban-
dons

534 VlfAC FtTNCTlOMS;

dons the materials of the bile from which it waS
neceflary it fhould be freed, and it is the acceflbry
phaenomenon, the peculiar ufe of the bile in di-
geftion, which is for a. moment impeded.

We have here another infi:ance of the facility
with which the organs can mutually fupply the
place of each other in their fund^ions.

The humorifts, according to their hypothefiSj
did not fail to afcribe the jaundice to bile conveyed
into the blood ; but the folly of this aflertion may
be eafily conceived.

If We fuppofe, that the bile fecreted by the
liver is abforbed by the lymphatic veffels of that
organ, in order to proceed into the blood, it muft
firfl pafs into the thoracic du6t, then into the fub-
clavian vein, then into the right fide of the heart,
then into the lungs, then into the left fide of the
heart, and thencfe into the aorta to be uniformly
diftributed by the arteries.

It is much more reafonable to think that the
venous blood, not being able in the liver to aban-
don the materials of the bile, from which it ought
to be freed before it pailes into the lungs, depofits
them in the cellular tiffiie of the different organs,
where they are afterwards digefted ; and that their
elements are taken up by the lymphatics, or ex-
pelled by perfpiration.

In acute difeafes-^ where there is a general de*

rangement,

3

CIRCULATION AND RESPIRATION. 33S

rangement, the adion of the liver, like that of the
other organs, is interrupted. In this cafe, if the
aiFedlion of the liver be of fuch a nature that its
fundion is weakened or impeded, and if the fe-
cretion of the bile cannot take place in that organ,
it will be feparated elfewhere, and there will be
fymptotns of jaundice, which are not defervingof
particular attention.

It refults from thefe conliderations, that the
blood undergoes in the liver changes analogous
to tbofe which it experiences in the lungs ; and
that under this point of view the liver and the
lungs are two organs which have analogous fane-
lions, as Fourcroy announced feveral years ago.

It evidently appears that the liver difcharges the
fundtion of the lungs, in circumftances when re-
fpiration has very little a<5livityi hence it is pro-
portionally very large in the foetus, which does
not yet fefpire ; it is in general very voluminous
in reptiles and fiOies, in which refpiration is ex-
ceedingly flow ; and it is exceedingly fmall in
birds, which have the pulmonary organ very large
and energetic.

In fome cafes of difeafe, fuch as phthifis, the
liver fometimes becomes exceedingly voluminous
and fat ; but it is very doubtful whether its a6tioti
be then increafed : it is much more probable, that
the fwelling of this organ is a ftate of difeafe,

during

VITAL FUNCTIONS.

during which the fecretion of the. bile is pei*
formed only with difficulty.

6j> When the venous blood has undergone a
fird affimilation in its pallage through the liver^^
as the Ijuiph and the chyle do in traverfing the
lymphatic glands, it returns from all the parta
hy means of the veins, which unite into two largd
1:runks : one of them brings back the blood from
the lower parts (the abdominal venacuva), and
the other from the upper parts (the thoracic vena-
cava). Thefe two veins proceed to the right
fide of the heart with the fmall cororiary vein i
the blood penetrates into the right auricle and
dilates it j when this auride has acquired a cer-
tain degree of dilatation it contra6^s, and the
blood pafles into the ventricle, except that part
which flows back. The blood accumulated in
the right ventricle diiiends it alfo j the fides of
this cavity contradl., and force the blood into the
pulmonary artery, from which it is expelled, to-
wards the lungs.

The blood cannot flow back from the ventricle
to the auricle on accouat of a valve (vajvuld
tr'icufpis)\ which oppofes it ,• and it cannot return
from the pulmonary artery to the ventricle, be-
caufe it is prevented by the fygmoid valves.

It is to be remarkcdj in the motion of the hearty

CIRCULATION AND RESPIRATION. 33/

that the right auricle contrafts at the fame time
as the left, and that the contraction of the two
ventricles is effefted at the fame moment ; fo that
the motion of the auricles and ventricles takes
place fucceffively.

68. The blood which pafles into the lungs is
blackifh, lefs warm (by two degrees), and a little
heavier than arterial blood : it exhibits, therefore,
the charadlers of venous blood.

The venous artery, Nvhich diftributes this blood
in the pulmonary organ, foon divides into two
trunks, one for each lung. Thefe arteries then
feparate into branches and rami : thefe rami into
ramufculi much fmailer, and the ramufculi fub-
divide into capillary velTcIs which elude the fight.
The venous blood is thus difperfed throughout
every part of the lung ; being reduced to a ftate
of extreme tenuity, it undergoes there, during the
a<5l of refpiration, certain changes, which make it
refume all the qualities of arterial blood ; it be-
comes red, florid, fpumous, warmer, and lighter.
It then returns to the left tide of the heart by
veins, which arife from every part of the lungs ;
which unite into rami and branches, and at lafl:
terminate in four large trunks, which proceed
into the left auricle.

The blood pafles thence into the ventricle of
the fame tide, and into the aorta, from which it

VOL. in. 2 is

33S VITAL FUNCTIONS.

is expelled by the arteries, to be again diftributed
to every part of the body.

69. The changes which the blood undergoes,
in paffing from the venous to the arterial ftate,
take place in the interval between the moment
when that fluid eludes our refearchcs by the arte-
ries, and that when we begin to fee it return by
the veins. It is in this infinitely fmall fpace,
which our eyes, aflifted by the beft inftruments,
cannot penetrate, that the phssnomena of refpi-
ration are efFedled.

It is proper here to remind the reader, that the
lung, in its intimate ftru6lure, exhibits ramifica-
tions of the bronchic cavities. The air, which pe-
netrates into this organ, enters by the mouth or the
iiofi:rils, pafles through the aperture of the glot-
tis, Iraverfes the larynx and the trachea, and en-
ters into all the divifions of the bronchise.

The bronchiss mufi: be confidered as aerian
vefiels, which divide, in the interior of the pal-
monary organ, into branches and rami; which
are fubdivided .into capillary raraufcuH of extreme
finenefs, and at length terminate in fmall cells,
which communicate with each other. All thefe
aerian pafTages are lined by a mucous membrane.

The arteries accompany the bronchic divifions,
fubdivide in the fame manner, and expand on
the fides of their cells ; the veins arife from thefe

, . fides.

CIRCULATION AND RESPIRATION. 330

fides, and in their paflage follow alfo, in an in-
verfe order, the divifions of the aerian paflages.

The air enters into the cavities of the bronchiae,
and ifluies from them alternately daring the move-
mentS' of infpirat-ion and expiration. Infpiration
takes place by the dilatation of the fides of the
breaft and the depreffion of the diaphragm.
The dilatation is efFe6ted by the a6lion of the
interCoftal mtifcles, which carry forwards and to-
wards the ribsj the fides of the breaft, and par-
ticularly towards the bottom of them. During
flrong infpirationSj this movement is affifi:ed by
the ax^ion of the mufcles attached to the fides of
the thorax, which extend to the bones of the
neckj of the flioulder, and of the arm.

The diaphragm, which in its natural fi:aie is
convex towards the breaft, finks down, becomes
horizontal by the conlra6tion of its mulcular fibres^
and increafes the capacity of the thorax.

' Expiration takes [)lace by the mere relaxation
of the mufcles which contributed to dilate the
breaft ; when the adlion of theie mufcles ceafes,
the parts refume their former ftate. Complete
expiration is favoured by the contra6iion of the
abdominal mufcles, and particularly thofe which
are attached to the bottom of the thorax. Thefe
rnufcies, in contrafting, lower the breaft, and
comprefs the inteftines, which deprefs again the
diaphraj^n, in the interior part of the thorax.

2 2 During

340 VITAL FUNCTIONS.

During the dilatation of the cavity of the tho-
rax, the lungs flre diftended 5 a fort of vacuity is
formed in the bronchic cavities, and the external
air immediately rufhes into them. This air then
jifues by the depreffion of the fides of the thorax,
and the relaxation of the diaphragm.

Refpiration, when once begun, never ceafes but
with life ; it is maintained by the a6lion of the
nerves, which diftriiDute themtelves to every part of
the organ of refpiration, and by the continual
neceffity which the blood has of experiencing
the changes it undergoes by the fund:ion of the
lungs.

The movements df the breaft are fuch, that
about eighteen infpirations take place in a mi-
nute»

From this iliort view of the movements of the
bread and of the llrudure of the aerian cavities
of the lungs, it may be readily conceived that the
air, vvhich penetrates into the bronchia^, follows
their ultimate divifions ; and that when it reaches
the laft bronchic cells it muft be almoft in imme-
diate contact with the blood.

It is now proper toi examine the changes which
the infpired air and the blood experience, in order
that we may thence deduce the nature of the
phagnomena which muft have taken place.

The atmofpheric air infpired is compofed of
about four-fifths of azote, and one fifth of oxygen.

The

CIRCULATION AND RESPIRATIOIT. ' 34 i

The expired air contains almoft the Tame quan-
tity of azote, but it now retains no more than
about the half of its oxygen, with a quantity of
carbonic acid gas, lefs than that of the oxygen,
which is wanting.

This important obfervation, for which we are
indebted to the pneumatic chemillry, has given
rite to various hypothefes.

The authors of the modern cheraiftry are of
opinion, that the carbonic acid gas produced is
formed in the lungs, by the combination of the
carbon, difengaged from the blood, with the oxy-
gen of the atmofphere ; but I afTured myfelf of
the fallacy of this opinion by the following ex-
periment. I placed fome Guinea pigs under a
bell glafs, filled alternately with atmofpheric air,
oxygen gas, azotic gas, and hydrogen gas ; and
in all thefe cafes there was nearly the fame quan-
tity of carbonic acid gas difengaged : its forma-
tion then is not owing to the prefence of oxygen
in the lungs.

Ghemifts have imagined alfo that a part of the
oxygen infpired is combined, in the lungs, with
the hydrogen difengaged from the blood ; and
that the v^ater emitted, during expiration, in the
flate of vapour, is the refult of their combina-
tion i but it is much more reafonable to fuppofe
that this vapour expired, is fecreted by the mu-

a 3 * cous

342 VITAL FUNCTIONS,

cous furfaces cf the bronchic cells, like all the
liquids which moiften the other organic furfaces.

The fuppofed formation of carbonic acid ga§
and water, by mecnns of the oxygen of the air, the
carbon, and the hydrogen of the blood, ought
neceflarily to be accompanied with a difengage-
ment of caloric; and it is to this driengagement
that animal heat and the habitual elevation of the
temperature were afcribed ; but the premifes be-
ing erroneous, the confequence deduced from them
muft be erroneous alfo.

Chauffier has iincc propofed an opinion, which
appears to be more probable. The carbonic acid
gas, he fays, is completely formed in the venous
blood; it is only difengaged by expiration, and
the oxygen gas is abforbed by the lymphatic
veflels.

This afiertion, much more agreeable to the
common phsenomena of the organization, appears
to me, however, in one of its points, to require
fome modification. Experiments made with great
care feem.to (hew, that this gas does not exifl: in
-the blood. Befides, it is a general obfervation,
that the blood contains no products of fecretion
completely formed ; it only pofleiies the princi-
ples of them which it aiiimilates in the organs of
fecretion.

Thus it is probable, that in the ad of refpira-

tion^

CIRCULATION AND RESPIRATION. 343

tibn, the blood frees itfelf from the conftituent
principles of the carbonic acid gas, in ihc/ecre^
tion of that gas : as it frees itfelf from the confti-
tuent principles of the bile, in the fecretion of
that fluid. On the other hand, the lungs are a
real Organ of digeftion : they aflimilate oxygen
gas, and probably a fmall quantity of azotic gas-;
thefe materials enter into the circulation, and
ferve for general nutrition and for the produ^ioo
of heat. , ; :^ ;-: t

The caloric, which maintains the habitual tecn-»
perament, and which is continually difengaged,
feemsfo pafs into the organization .by the pulmo-
nary organ, where it is abforbed V^ith a portion of
atmofpheric air.

In the different claiTes of animals with lungs,
it is indeed obferved, that the animal heat follows
the ratio of the extent and adivity of the organ
of refpiration . Hence it is at the higheft degree
in birds ; lefs in the mammalia, and very incon-
liderable in reptiles.

The blood which proceeds to the lungs has
a blackifh colour ; and it returns from that organ
with a beautiful red tint. Chemifts afcribe the
beautiful red colour of the arterial blood to the
abforption of oxygen ; becaufe the venous blood
becomes red when in contact with that gas ; but
it aflbmes the fame colour by warmth, and ani-

z 4 mals

344 VITAL FUNCTIONS.

mals reduced to a ftate of afphyxia, by carbonic
acid gas and the gafeous oxide of carbon, have
very red blood alfo.

It is probable that the venous blood lofes its
blackifh colour in the lungs, by freeing itfelf from
thofe principles which form carbonic acid gas.
But, however this may be, a difference of colour
is, in general, a matter of very little importance.
It- is well known, that different arrangements of
the fame moleculse of a body are fufficient to pro-
duce changes, exceedingly various, in the reflec-
tion of the luminous rays, and confequently in
its coloration. We know that the arterial blood
is reddey, more fpumous, and warmer than the
venous blood ; but chemical analyfis fhews no
efiential difference between thefe two kinds of
bloodj in regard to their compofition.

70. When refpiration has been fuddenly fuf-
.pended, death takes place in a few minutes. It
was natural, therefore, that attempts fhould be
made to account for this extraordinary phaeno-
.menon,

Chemifts have fuppofed, that as the abforption
•of oxygen by the blood is the principal pheno-
menon of refpiration, death enfues when this ab-
forption cannot take place ; becaufe the bloody
being .deprived of its habitual ftimulantj can no
■Z-i ■'■ longer

CIRCULATION AND RESPIRATION-. ^345

longer excite, in a proper manner, the lef*" ven-
tricle of the heart, which then ceafes to contract.

But, in the different kinds of afphyxia, it is
obferved, in general, that the aortic ventricle is
always empty, while the pulmonary ventricle Is
full ; which evidently proves, that the left lide of
the heart did not ceafe to contrail till it ceafed
to receive blood, ■'

On the other hand, Guinea pigs expofed to
azotic gas, and very pure hydrogen gas, live a
confiderable time, and their death feems to be
occalioned, in part, by the prefence of the car-
bonic acid gas expectorated ; fo that the want of
oxygen, in refpiratibn, does not become fatal fo
fpeedily as has been fuppofed.

Afphyxiae may be diftinguifhed into three forts:
ifl. Thole which take place in confequence of the
entrance of air into the lungs being fuddenly in-
tercepted : zd. Thofe which take plac^ when the
lungs, inflead of receiving atmofpheric air, receive
a foreign gas, which however exercifes no perni-
cious adlion : 3d. Thofe which refult from the
introduction into the air-paflages of any fu|?-
flance which exercifes a fpeedy and fatal adlion.

Afphyxiee, which take place in confequence of
the air being prevented from entering the lungs,
are thofe which refult from the different modes of
itrangulation, fuffocation, and fubmerfion. It is

probable

246 ^ VITAL FUNCTIONS,

probable that in all thefe cafes death enfues, be-
caufe the play of the lungs is neceflary to pro-
mote the circulation of the bloody the whole of
which paffes through that organ : refpiration be-
ing fuddenly fufpended, circulation may be pre-
vented ; and death, which at firft is only appa-
rent, >foon becomes real, if fpeedy relief be not
applied. Death, in all probability, takes place fo
foon, merely becaufe the organization has not
time to accommodate itfelf to fo great and fo ab-
rupt a derangement. It is well known that divers
gradually habituate themfcK^es to remain under
water for a longer time than is fufficient to drown
,ibme perfons completely.

When an animal is immeifed in very pure azo-
tic or hydrogen gas, the play of refpiration is not
fofpended ; infpiration and expiration continue to
take place J circulation is not interrupted, and life
continues. The lungs, however, are deprived of
their habitual aliment ; and when this privation is
fuddcn, and continues too long, the animal at
length perifhes. But, if it be flowly habituated to
refpire in one of thefe gafes, and if care be taken
to ablorb the carbonic acid gas expectorated, the
reaction of which on the lungs is fo fatal, it may
readily be conceived that the privation of oxygen
gas may be endured for a very confiderable time.
Azotic and hydrogen gas, therefore^ do not kill,

but

CIRCULATION AND RESPIRATION. 347

but fufFer the animal to die flowly, becaufe they
merely maintain the play of refpiration, without
fupplying the aliment necefTary for life.

The afphyxiaj 'vhich take place in confequence
of deleterious fabftances conveyed into the lungs
are the mod numerous. They are thofe occa*
lioned by the infpiration of the carbonic acid gas,
difeneraffed from wine or beer calks in a ftate offer-
mentation^ from lime-kilns, &c.; by the infpiration
of the carbonated hydrogen gas produced by char-
coal, when it begins to burn with a flightly blue-
ifh flame, and by the infpiration of the vapours*
exhaled under certain circumflances from privies^
drains, burying grounds, &c. Thefe fubftances,
conveyed into the lungs with the infpired air,
produce, fometimes, on the nerves of that part, an
impreffion fufficiently violent to occafion a ge-
neral derangement of the nervous adiion and fud-
den death. Thefe afphyxiae exhibit a phseno-
menon analogous to poifoning, by thofe fubftances
called narcotics.

When the deleterious fubftances conveyed into
the. lungs are not fufficiently ftrong to produce
afphyxia, they may give rife to a highly varied
feries of morbific phaenomena. Thus the greater
part of epidemic fevers feem to be produced by
emanations from vegetable or animal fubftances, in
a ftate of putrefa6lion, conveyed iqto the lungs,

and

348 VITAL FUNCTIONS.

and efpecially of individuals who have a difpoii-
tion fuited to them. In the plague^ thefe Tub-
fiances introduced in a larger quantity into thefe
organs of a weak individual, already altered by
fear and defpair, may produce fudden death ; as
has been obferved in all cafes where the plague
has been epidemical. Deaths on fuch occafions,
is a real afphyxia.

^i. The venous blood, after pafling through
the lung,^^ and having refumed there the qualities
of arterial blood, proceeds into the left fide of the
heart by four large veins, which depofits it in the
auricle, whence it pailes into the ventricle, and
thence into the aorta, to be again diftributed to
all the organs by means of the arteries.

The atmofpheric air infpircd, after remaining
in the lungs, and lofing there a part of its oxy-
gen, and perhaps a fmall quantity of azote, is in
part expelled at each expiration along with the
carbonic acid gas which has been excreted.

But air vv^hich enters and continually iiTues
through a narrow aperture, furnifhed with a
moveable appendage, and which may be driven
with greater or lefs force into a cavity where the
found produced is modified before it ifTues from
it, furnifhes all the conditions neccflary for a wind
inftrument. Thus the air, after conveying into

thf

CIRCULATION AND RESPIRATION, 34Q

the lungs one of the principal aliments of life
and the Iburce of heat, may in its return receive
a vibratory movement, which is trarafmitied to a
diftance; and, in the formation of the voice, con-
liitutes an artificial lign exceedingly proper for
the improvement of the mind, and the means
which have the greateft tendency to unite men in
the bonds of fociety.

The vocal organ is an apparatus, the fund:ion
of which is difficult to be underftood ; and the
phyfiologift who hears the harmonious founds
which proceed from fome throats, is much more
aftonifhed by the difficulty overcome, than by
the efFed: produced ; for it is perhaps hardly pof-
fible to conceive an inflrument more refradory
than the vocal organ of man. But this proves
how far the parts of the body, by their furprifing
flexibility, can overcome the greatefl difficulties,
and furmount every obftacle.

The fimplefi and moft perfect vocal organ is,
no doubt, that of birds. Thefe animals, at the
union of the bronchlse, on the fides of the lower
part of their trachea, have two membranous folds,
which in part clofe the aperture of the latter.
The air expelled from the lungs makes thefe
membranes vibrate ; their vibrations are commu-
nicated to the air, and a found is thus produced.
This' inferior hrj?w is, for the moit part, fur-

nillied

350 VITAL FUNCTIONS.

niflied with fmall mufcles, fufceptible of caufing
a variation in its movements. The trachea, v/hich
confifts of very fine cartilaginous rings united by a
membrane, is capable of being lengthened or
Ihortened.

' In the laft place, the fuperior larynx has an
aperture fufceptible of contracting or dilating, fo
that the vocal organ of thefe animals is a wind in-
ilrument, entirely analogous to thofe of the order
of horns ; its mouth is towards the lungs *.

If the theory of ftringed inflruments be applied
to this wind inftrument, according to the method
of Euler, it maybe fubjeded to calculation ; and
the length of the ftring, its degree of tenlion, and
its vibrating force, may be appreciated.

The length of the ftring is meafured by that of
the trachea ; its degree of tenfion by the aper-
ture of the fuperior larynx ; and the vibrating force
by the expulfion of air from the lungs.

In man, the vocal organ exhibits another ar-
rangement; there is no larynx at the bottom of
the trachea ; the air expelled from the lungs by
the bronchise traverfes the trachea, as in a
conducting tube, and at its paflage through the
larynx meets with the epiglottis. This naoveable
cartilage, when ftruck with force, vibrates, and

"* Sec the Memoir of C. Cuvier.

makes

CIRCULATION AND RESPIRATION". 351

makes the furrounding air enter into a ftate of
vibration alfo. The found, therefore, is only
produced on its ilTuing from the larynx, and is
afterwards modified in its paiTage through the
mouth and noftrils.

To judge of the value of the vocal organ in its
natural fiate, and of the quality of its tone, no-
thing is neceflary but to hear the cries of an in-
fant ; and when we reflect that means have been
devifed to produce from this inftrument the mod
harmonious founds, it is hardly poffible to con-
ceive how fo great a difficulty could be ovo*-
come.

The founds produced at the aperture of the
larynx, when accented by the different parts of
the moutji, form j^^^^:^', and modulated founds
con^hutQ Jlnging.

The vocal organ of man, though attended with
lefs advantage than that of birds, exhibits an ana-
logous ftruclure, and may be referred alfo to the
theory of flringed iniiruments.

The lenglh of the cord is meafured by the dif-
tance comprehended between the aperture of the
glottis and that of the mouth or noftrils ; this
length may be varied by the elevation or depref-
lion of the larynx, and even by the pofition of
the lips.

The vibrating force depends on that of the

lungs,

352 VITAL FUNCTIONS.

lungs, by which the air is expelled; and the
degree of tenlion on the variable aperture of the
mouth.

Though the voeal organ of man be a wind in-
Urument, not very advantageous, it affords a great
many refource^ in regard to its innprovement ;
thus the found produced, on the air iffuing from
the larynx, may pafs from grave to acute, accord-
ing as the aperture of the glottis is greater or
fmaller ; as the larynx is deprefled or elevated,
and the neck more oi* lefs elongated 5 and accord-
ing as the mouth is more or lefs open. Sounds
when once formed, may be modified a great
many ways, by the varied movements of the
tongue, the cheeks, the teeth, the lips, &c., and
by its paffage through the noftrils. Sounds, ac-
cording as they have been modified by any of
thefe organs, are diftinguiflied by the names of
labial, dento-lingual, palato-lingual, &c. articu-
lations, &c. {^ee. Lexicograplne de'Butet.)

Man has employed the found which may be
produced by air expired with velocity as a con-
ventional lign, merely becaufe pain obliged him
to emit cries, which induced him to think that
he might render thefe cries of utility ; for if the
air, in iffuing from the lungs, had not been ac-
companied with found, he would have remained
as dumb as a perfon born deaf.

When

CIRCULATION AND llESPlilATlON* 353

When children hurry too much in the accentu-
ation of founds, they repeat the fame lyllables
foveral times, which is called ftammering. This
defe6^, when not of too long {landing, may be
corredled, by making the child acquire a habit of
pronguncing each lyllable difl:in<5tly, one after
the oth^r.

VOL. in. % h . AGTION

V 334 . J-

JlCtion of the organs of re:.
production;

72. xLvERY organized being is prodoced by aw-
other fimilar to itj and from which it is feparated,
after having formed a part of it.

Organized beings, whofe mode of reproduction
is known, exhibit two ways by which they may
completely attain to this fmiClion.

When a part of an organized being is fufcep-
tible of being detached from it to form a limilar
being, this mode of reprodudion is called that by
flips ; thus the germs of fojne plants detach them-
felves from the Rem, and being received in the
earthj, produce other plants, as is the' cafe with
the ornithogalus. Some bulbous plants produce
fmall bulbs, which increafe, fend forth roots, and
detach Ihemfelves from the parent bulb to form
new ones. Polypes fend cut gems from every
part of their bodies, whicb increaTe in fizG, detach
themfelves, and form entire polypes. The lafi: ar-
ticulation of the naides increafes and detaches it^
felf to form a perfeCl animal.

For the fame reafon, v.'e ought to be able to
divide an organized being into feveral parts .fuf-
- ceptible-

ORGANS OP REPRODUCTION. 355

ceptlble of reproclucriig itfelf^ provided each of
them contains a bud or germ. Thus a twig de*-
tached from the root of a tree may produce an-
other tree, provided this twig contaifTS a bud. A
polype may be ciit into a great number of parts,
^hich produce entire polypes.

But what appears to be very extraordinary is,
that a worm which has a head, a trunk, and a
iail, atll very diftind, fhould be fufceptible of di-
vifion into feveral pieces, capable of reproducing
the parts whith are wariting to them ; though in
this animal the head contains a cerebral f}ftem,
and though the apparatus of generation is in-
iiilated.

^3. The feeds and the ova, like the buds and
germs, are fmall bodies'vvhich detach themfelves,
and by their development produce beings fimilar
to thofe from which they proceeded ; but they
differ from them in this refpe6l, that they have
jieed of being ^Yev\ai\{[yfecu?idated. Living beings,
which multiply by flips, reproduce themfelves alio
from feeds and from ova.

The individual which bears the feed or the esfo:
may alfo bear the fecundating organ ; or thefe two
organs may be in feparate individuals.

The union, in the fame individual, of the feed

or the ovum, and the organ proper for fecundating

kj, conftitutes hermaphrodifm. The feparation

2 A 2 of

356 VITAL FUNCTIONS.

of them in two diftind: individuals efiablifhes
difference of fex.

The greater number of vegetables are herma-
phrodites. Thre male parts may be united in the
fame flower with the female parts, or both thefe
parts tnay be found in feparate flowers.
'Moll fhell animals arc hermaphrodites; the
eggs are fecundated by the male organ, in de-
fcending along the oviduA. Some of thefe ani-
mals, though provided with male and female or-
gans, have ftill need of copulation ; of this kind
are the fnail and the Aug. It does not, however,
appear that in the copulation of thefe animals the
male organ of the one can ferve to fecundate th6
egg of the other ; there is more reafon to think
that their copulation is a Simulant proper for fa-
vouring their individual fecundation.

74. The feeds and the eggs are compbfed of
the germ, and the nutritive apparatus which is
deflined to promote its firft development.

In plants and the greater number of animals,
the nutritive apparatus, which envelops the germ,
is fupplied, at the expenfe of the mother, with a
quantity of nutritive fubftance fufficient for its firft
increafe, and for enabling it to break the (hell, ii;!
order to live by its own flrength.

In the mammalia, the nutritive apparatus is
fixed to the fides of the matrix, and draws from

it

ORGANS OP REPRODUCTION. 357

it juiees which it aflimilates and diftributes to the
embryo. ; •. j^r^r-y. ,

The ovarium muft have acquired its oolnplete
development, before the feeda or the eggs, which
it contains, can be fulceptible of fecundation.^ .

The feeds or the eggs may detach themfelves
from the ovarium before or after their fecui^aT

lion* rt f^fljK;!'?*;. ■.^!; ,

The eggs detached from the ovarium, before
fecundation, may be afterwards fecundated, or
may not be fufceptible of it.

Some feeds ripen without having been fecun-
dated ; but they remain barren.

The eggs of birds often come to maturity with.-
out having been fecundated, and in that cafe are
no longer fufceptible of it *.

In all thefe cafes, the nutritive apparatus afTumes
a proper increafe at the expenfe of the mother, in
order to ferve for the nutrition of the germ, whe-
ther the latter is to be developed or not.

The ova feparated and ejecSted from the ova-
rium of certain ofTeous fifhes may be fecundated ;
and thofe of feveral reptiles> fuch as frogs, are.

* It Is probable that when thefc feeds or eggs have acquired
their full increafe before fecundationi 'the thick ftrdng covering
which furrourtdi the gertti is aft obftacli to their future foiun-

a A 3 The

358 VITAL S-UNCTIONSo

The liquor of the male organ fufpends this putre-
fadion, even when in an advanced ftate, and car?
air© produce fecundation.

76. Though the prefence of the organ of gene-
ration in the male and in the female is not necef-
fary to the life of the individuals, and though
thefe organs appear, as we may fay, to have been
fuperadded, they exercife a v6ry ftriking influ-
ence on the whole of the organization, as is ob-
ferved by the difference which exifts between in-,
dividuals provided with thefe organs and thofe
which are deprived of them.

In organized beings, which exhibit two different
fexes, the a6l of fecundation is performed by
a complex apparatus of organs ; life is exalted,
acquires more energy, and feems to be prepared
as for an important aft. All the powers are di-
rected to and concentrated in the generating -or-
gans ; and after fecundarion the individuals expe-
rience a manifeft ftate of lano-uor. The male

o

feems to have made the greateft effort, and (hews
a more remarkable depreffion ; but at that pe-
riod his iaik is finifned, and a new one begins
for the female.

Some plants, fuch as pinks and the lychnis,
when forced to llerility, live longer and refifl the
cold better.

Butterflies

ORGANS OF REPRODUCTION. _ 359

Butterflies exift under the winged form, only
ki., order to reproduce themfelveSj and after fatis-
fy'mg this law they foon die.

In order that fome animals may fatten, they
are deprived of the eflential organs of genera-
tion.

76. The male, of almoft all animals which
copulate, places himfelf on the back of the female
during coition ; in fome, however, there are cer-
tain difpoiitions, fuch as a broad thick tail, which
prevent this mode of copulation : the female of
the hedge-hog and porcupine places herfelf on her
back. This mode of copulation is that of ceta-
ceous animals, the rays, fquali, and the crocodile.
The female elephant only bends her fare legs ;
the oftrieh lies down on its belly ; ferpents entwiffc
themfelves with each other, &;c. Some reptiles,
fuch as toads, adhere fo flrongly to the female,
that they will rather fufTer themfelves to be torn
than to feparale from them.

Infe^ls almoft always exhibit in their fore claws
the means proper for keeping themfelves Hxed on
the female; and the femnles^alfo have frequently
hooks by which they lay hold of the male daring
their long copulation. The duration of this acl
varies in the different clafles: in birds it fcarcely
continues a few feconds ; it is longer among the
mammalia, and particularly thofe which have no-
2 A 4 feminal

StiO VITAL FUNCTIONS.

feminal veflel, as is the cafe with the dog j in
the laft place, it is exceffively long among fome
reptiles, fuch as frogs, which continue in a Hate of
copulation even forty days.

'^ All organiaed beings continually reproduce
themfelves in this manner, amidft languor and
tranfports of pleafure."

77. Among the mammalia, the firil period of
conception is indeed very obfcure j but generation
has been too much conlidered as a myjiery. This
phaenomenon is no more obfcure, and perhaps is
lefs fo than many others that take place in organs,
the fmallnefs or tranfparency of which makes
them elude all our means of obfervation.

In reprodu(5lion by flips, the adlion of life is
continued without interruption, from one race to
another, by means of buds or germs. Thefe are
fmall bodies, which by their fpontaneous develop-
ment produce beings (imilar to thofc from which
they detach themfelves.

In reprodu6lion, by nieans of femen or ova, the
germs contained in thefe fmall bodies attain only
to a certain degree of development by the influ-
ence of the vital atflion of the mother ; and whe*-
ther they remain attached to her, or are depofited,
they acquire no further increafe. But if at that
period they, receive the fecundating impreffion of
the produd of the male organ, they again enter

into

ORGANS OF REPRODUCTION. SQl

into aftion ; the (emen and ova are then exactly
in the fame fituation as buds and germs : they ex-
hibit different ways which lead to the fame end,
and which produce the fame refults.

78. In what manner does the prolific fubftance
vivify the germ ? And what takes place at the
moment of conception?

This phasnomenon is not, as fome philofo-
phers imagine, above human comprehenlion 5 but
merely below the reach of our light ^ and we caa
form no judgment but of things which ftrike fome
of our fenfes.

If one of the animalcula of the femen could
come and tell u« what is obferved in the ovarium
at the moment of fecundation, and during the
iirft days of geftation, it would relate a feries o(
fadls, which certainly would not exceed the limits
of the human comprehenfion ; but our coarfe
Icyes cannot perceive the hundredth part of a line,
■ while there are organized beings, much fmaller,
which are endowed with the powers of per-
ception, digef^ion, and reproduflion. As we have
no data, therefore, in regard to tbefe firfl phse-
nomena, we fhall not attempt to give any ex-
planation of them.

79. Was it neceflary that the whole feries of
beings, paft and to come, fhould cxiit in the firft

feeds

S§2 VITAL FUNCTIONS,.

feeds and the firft ova ? One might as well alk,
whether the fmall vegetables, which fcarcely cover
the naked fides of a chain of mountains, contain
within them the immgnfe foreft which is to exift
there a thoufand years after ^ or, whether all the
flames by which Troj' was confumed exifted in
the firft fpark Aruck from a piece of flint ? Iq
all thefe phaenomena \ve ought to fee only a con-
tinuity of adion,

80. The germs contained in feeds and in dva,
when once fecundated by coming into conta<5l
>vith the lecretion of the ftialc organ, develop
themfelves afterwards by means of a nutritive ap-
paratus furqiOied by the female. This apparatus
exhibits numerous varietie?, in the different clafles
of living beings. It, however, always confifls of
a vafcular and membranous .reticulation, which
affords he means of circulation between it and
the germ. Thefe two fvflems are fo connected
thac it can hardly be conceived how they could
have been feparated. This arrangement is one of
the ftrongefi: proofs of the pre-exifi:ence of the
germs in the female. The nutritive apparatus of
the germ is developed by a continuity of the vital
aflion of the mother.

In oviparous animals, properly fo called, this
apparatus may acquire its full expanfipn, whether
the germ is to be developed or not: it then de-
taches

ORGANS OF B-EPRODUCTION. 30$

^sches itfelf from the mother, to ferve for the fur-
ther development of the fecundated germ.

In vegetables this apparatus does not, in ge-
neral, attain to maturity till after the fecundation
of the germ j it then detaches itfelf, and ferves for
the iame purpofe as in the preceding cafe.
, Among the mammalia, the nutritive apparatus is
not developed till after conception ; and does not
ferve for the increafe of the embryo, but fo far
as it remains attached to the mother.

In all cafes a circulation is eftabliflied between
the embryo and the nutritive apparatus, by the
new vital ai5iion which the germ receives at the
moment of fecundation,

8 1. The nutritive apparatus of the feed con-
lifts eflentially of one or two cotyledons, which
are continued with the germ. The cotyledons, for
the moil part, are furrounded by a perifpcrma,
which furnifhes them with the firft materials of
nutrition. The whole is enclofed in a triple co-
vering.

After fecundation, the germ and the obtyledons
expand and increafe in the fame proportion. The
cotyledons derive from the perifperma the fiF{l:
nutritive juices; the covering of the feed then
burfts J the cotyledons increafe in fize, and ac-
quire from the earth and the air other alimentary
fubflances, which they continue to affimilate and

to

^04 riTAL FUffCTIONS^

to diflribute to the embryo. The radiculae and
plumula are then feen gradually to develop them-
felves ; and when the fmall plant is in a ftate ca-
pable of appropriating to itfelf the nutritive mole-
culae fuited to it, the cotyledons wither and de-
tach themfelves.

82. The nutritive apparatus of the ovunn of
birds exifts chiefly in the membrane of the yolk,
which is continued with the inteftines of the em-
bryo. This membrane gradually abforbs the white
fubflance of the egg, which pafTes through the
yolk ; it then abforbs the yellow fluid itfelf; afTi-
milates thefe materials, and tranfmits them to the
embryo to ferve for its firfl increafe.

In this mode of growth^ the nutritive apparatus
isdiminifhcd in proportion as the animal increafes.
When the latter has acquired a certain degree of
iirength, it makes a continued vertical motion
with its head; breaks in this manner its fhell^
by means of a fmall, fharp, and very hard body
"which is above its beak; and at length ilTues forth j
to enjoy a new life.

As the bird, freed from its fhell, is as yet inca-
pable of providing for its wants, it is not aban-
doned by its mother. The latter begins to nourifh
it with a whitifh liquor fecreted from her crop ;
ihe then fupplies it with more nutritive aliments,
of which (he goes in feareh. When the young
' animal

ORGANS OP REPRODUCTION. 3(53

animal, is iirong enough to make ufe of its wings,
it deferts its mother, and feeksfor its nouriilament
wherever it can.

Among birds, it is obferved, in general, that the
male which has fecundated the ova does not aban-
don the female, and participates in the care of
educating the young ; he affifts in the conftruc-
tion of the neft ; fits on the eggs in the abfenee of
the female, and brings nourilhment to the young*
When the education is finithed, the male and fe-
male feparate, and the next feafon form new con-^
ne6tions.

Though the development of the ova among
reptiles, fifhes, and animals, without vertebras, has
not been obferved with the fame care, every thing
fpems to announce that it takes place, in general^
in a manner analogous to that of the ova of birds.

Sj. Seeds and ova, in order to be developed,
require to b^ placed in atmofpheres at different
degrees of heat^ moifture, and perhaps of elecSlri-
city.

The ova of fifhes and ferpents are developed at
the ufual temperature of the climates where they
exift. Thofe of fome infedls, fuch as the filk*
worm, require a flight heat; and thofe of birds re-^
quire a heat at leafl of 85 degrees.

The feeds of all vegetables, and the ova of fbme
microfgopic animals, require heat and moiflure.

Th©

VITAL FUNCTIONS.

The life of Ibme fmall vegetables, and of certaiii
inicrofcopie animals, which requires the continual
' prefcBce of humidity, may, when deprived of it^
he fufpended for a period, often of corifiderable
length, and it may refume its adivity when hu-
midity is reltored to them, as h obferved in the
confervtfe and the wheel infedls.

Seeds and ova, which are developed only at $.
♦jcertain degree of heat, can often be preferved for
a long time, and even a great ntimber of years^-
and again enter into action when fabje6led to that
temperament which is fuited to them.

This difpoiition may ferve to account for the
ftidden appearance, as is often the cafe, of a great
T-umber of infedls and fmall vegetables, in places
where the prefence of organized beings v/as not
fufpedledi

84. Among reptiles with a naked Ikin, and the
greater part of infedls, the animal which begins to
develop itielf has no refemblance to that whicfif
.gave it life :' it exhibits a different form, and other
fyftems of organs. Thus the tadpoles df molt
aquatic reptiles lofe their bfanchiss, their tail, and
their whole fein j acquire four legs; refpire by
means of lungs ; and at length exhibit an aniiiial
entirely different, which fucceeds the firft.

Infeds, brought forth under the form of cater-^
pillars, pafs. afterwards to the iiate of chryfalide ;

and

ORGANS OF REPRODUCTION. 3^7

and at length expand into a butterfly. This ani-
mal, indeed, exhibits all the parts proper for un-
dergoing thefe jtrjetarnorphofes; and it appears as if
three different animals were developed in fuceef-
lion. The organs of generattap are obferved pnly
in the ftate of butterfly.

^^, The nutritive apparatus of the germ of the
mammalia conflfl:s, like that of feeds, in one or
mpr^ cotyledons. Thefe organs remain attached
to the uterus, and derive from it juices which they
aflimilate for their development, and fof that of
the embryo.

In this apparatus, as in that of birds, the germ
is immerfed jn a fecreted fluid, and retained by s
membrane, amnios.

In the lad place, this apparatus does not efleo-
tially difl'er'from that of feeds and ova, but by
being attached to the uterus.

%6^ At the moment of fecundation, the tube
enters into a fort of erecflipn, and its wide end is
applied to a part of the ovarium. This organ ex-
hibits then, in that part, a fmall tumour, which lu-*
creafes and gradually fwells up.

This tumour feeras :to contain only a mucous

matter, firft whitifli and then of a redd i{|i yellow

colour ; it aftei'wards flnks down, and the ovarium

retains a fmaii fear.: Durmg the firfl; day^ of cpn-

2 qeption.

B68 tirAL PUNCTKJWS*

eeption, nothing is obferved in the tube but a
fhapelefs mafs of mucous matter, which gradually
increafes, and is conveyed Into the matrix, where
it acquires more volume ; and which, after a pe-
riod of greater or lefs duration, fufFers its different
parts to be diftinguifbed.

57. The fundion of the cotyledons or placenta
is to draw off from the mother the nutritive juices
•which ferve for their increafe and for that of the
foetus, \)y means of the circulation which is efta-
blilhed between them.

The blood, which proceeds to the foetus, feems
ia undergo, in its paflage through the placenta,
changes analogous to thofe which it experiences
in its paflage through the liver or the lungs of
adults : it refumes there new vital properties.

When the placenta has acquired a certain in-
creafe or fort of maturity, and when the foetus is
fufficiently llrong to be able to refpire, the matrix
violently, diftended experiences pains, which forces
it to contrail and to expel both.

Among the mammalia, the young animal, wheg
it ifliies from the matrix, remains attached to the
mother by the need of ladlation ; and the mother
herfelf is excited to empty her dugs, and beftow
care and attention on her young.

8S. Daring gcftation, the dugs fwell and be-
3 - come

ORGANS OP REPRODUCTION". QQq

come fenfible. Some days after parturition, a
new mode of adlion takes place in thefe organs ;
fecretion of milk is eftablifhed, and continues in
confeqLience of the animal being fuckled.

89. The teats differ bot4i jn regard to their
number and poiition, in the different dafies of
animals : in the bat, elephant, and apes, they are
in the bread ; in moil quadrupeds on the abdo-
men ; in cetaceous animals on the fides of the
anus, &c.

The teats are at leaft two in number : ruminat-
ing animals have four, and the fow has even four-
teen.-

90. All the mammalia," as well as the other
clafles of animals, find themfelves urged, at certain
periods, by a defire of reproducing themfelves;
their genital parts are then more voluminous,
and they experience a fort of turgefcence : it
is obferved alfo that fome females have a run-
ning, fometimes of a reddifti colour, ft-om the
vagina. - ; ,.

Among raofl of the mammalia, the male re-
mains very little attached to the female after copu-
lation. It is however obferved ^tbat the carnive-
rous fpecies, which experie-nce, the greateil diffi-
culty in procuring their nourifhment, continue
longer united ; and^mong thefe fpecies the males
rvoL. HI. 2 B , even

S70 VltAL FUNCTIONS.

even often participate in the firft cares beftowed on
the education of the young.

91. Organized beings, in general, reproduce
themfelves only by means of individuals of the
fame fpecies : it is however not uncommon to fee
different fpecies copulate and produce young.
This baftard fecundation takes place, for the moft
part, among fpecies which approach neareft to the
fame genus ; and the individuals refulting from it,
in the vegetable kingdom, are diftinguithed by the
name of hyhrides ; and in the animal, by that of
mules. Individuals produced by the copulation of
different varieties, in the fame fpecies, are called
meflejs.

It is very often remarked that hyhrides, mules ^
and mejlefe, are Wronger than the individuals
which produced them ; and this circumftance has
fhown the advantage of croffing the breed.

Hybrid plants are fruitful and multiply their va-
rieties. Several botaniils, however, ailert that the
germinating property of feeds which arife from hy-
brid plants does not extend beyond the fecond'
generation -

Mules, "among birds, are generally capable of
reprodu61ion. Among the mammalia, they lofe
this property, and remain barren.

Meftefe reproduce themfelves, with the pecu-s
liar charaders of their variety.

Hybrides,

ORGANS OF REPRODUCTION-. 37^

Hybrides, mules, and meftefe, generally have a
relemblance to the mother in their interior and
fundamental parts j and to the male in their ex-
terior and acceflbry parts j which tends to prove,
that the germs pre-exifted in the female, and that
the male, by fecundating them^ could only modify
them faperficially.

Every peculiarity of fl:ru(5lurej every defeiSl of
conformation, and even every organic difpofition
or aptitude for certain faculties, is fufceptible of
being at length tranfmitted by t/he way of genera-
tion. It is in confequence of this property that
the fame forms and the fame qualities are preferved
in plants, and in teveral races of animals, as dogs
and hories ; and that certain organic maladies
are perpetuated, fuch as the bunch of the ele-
phant, &c.

The crofiing of breeds, efpecially if the moll
beautiful females be chofen for that purpofe, is the
beft means to correct, in the fpeediefi: manner
poflible, eflential organic defeats, and to obtain
races Wronger and more beautiful.

Culture or education, by which organized beings
are continually modified, and generation which
tends to propagate the changes produced, are the
two means which may powerfully concur towards
the improvement, as well as the degradation of
fpecies, according to the manner in which they ar$
dire(5led. ^

2 B 2 92. What;

37^ VITAL FUNCTIONS.

92. What has been faid, in general, on the
reprodu6lion of all organized beings, and on that
of the mammalia in particular, is applicable to the
human fpecies. In the examination, therefore,
of that funcftion, we fhall take notice only of the
principal, fa6ls which feem more particularly to
demand our attention.

The period of puberty is announced, in both
fexes, by very remarkable changes: in girls who
have attained to the age of 14 or 15, or fooner or
later according to the climate, it is obferved that
the giddinefs and livelinefs of early youth de-
creafe, and that they become more thoughtful.
The bofom begins to fvvell, and gradually
acquires a greater volume ; the pubis is covered
with down ; the pelvis completing its expantion,
aflumes its proper form, and menflruation com-
mences.

In boys, the period of puberty takes place two
or three years later ; they become lefs boiflerous,
and acquire a more ferious turn ; the voice pafles
from acute to grave, and becomes an odave
lower ; the quality of the tone often entirely
changes ; the genitals are covered with hair, and
experience a fort of inflahtaneous atid painful tur-
gefce nee,

Man is irrefifiibly urged to reproduction, as
well as to felf-prefervation, by the painful fenfation
of rieed ; and the plcafure he experiences in fatis-

fying

ORGANS OF REPRODUCTION. 373

fying that need induces hiril to repeat often the
a6t of reprodu6lion.

If young perfons of a ftrong conftitution, unin-
formed, and who live in a flate of idlenefs, be
carefully obferved at the epoch of puberty, when
the organs of reprodudlion begin to acquire their
full development, it will be found that they ex-
perience a fort of tranfient languor, dejeftion, and
exaltation ; this ftate is continually renewed, and
foon becomes very painful. They experience inf
the genitals a fort of heat and uneafy pruritus,
which obliges them to fix their attention on this<
i)'flem of organs ; this uneafmefs, which becomes
more and more infupportable, induces the fexes to
approach each other, and the painful fi:ate which
they experience, and which they naturally wifh to
get rid of, condu(fl:s them at length to the a6t, of
reprodudlion.

In the human fpecies, it is not obferved that the
delire of reproduction is renewed at certain periods.

It is however probable that this peculiarity is a
refult of civilization ; that in the ftate of nature
there are fome periods more ftriking in this re-
fpe6l, and that, in women, they correfpond with
thofe of menftruatLon.

93. According to numerous experiments and
obfervations ijiade by Haller and others on ani-
mals, for the purpofe of throwing more light on
2 B 3 the

374 VITAL FUNCTIONS.

the pbsenomenon of reprodu6lion, it rcfnlts that,
during copulation, the uterine tube experiences a
fort of eredion, and that the broad end of it is ap-
plied to the ovarium.

It is probable that in this fl:ate the prolific fluid
proceeds to the ovarium, traverfing the uterus and
the tube, and that it effects the fecundation of one
or more germs, contained in the fmall veticles
correfponding to the part of the ovarium to which
the wide end of the tube is applied.

The quantity of fperm neceflary to efFeft fecun-
dation muft be infinitely fmall ; for under fome fa-
vourable circumftances the vapour or even odour
of that fubflance, conveyed into the ovarium,
feems to be fofficient to communicate to the germs
a vital movement.

Some days after conception it is obferved, that
one of the.veftcles of the ovarium fwells ; it then
buriis, and the vifcous fluid it contained' enters
the tube. The cicatrix refulting from this rup-
ture is gradually formed, and-always leaves a fort
of tubercle with a yellow fpot.

The cicatrix and the yellow fpot -indicate, in
general, that fecundation has taken place. . Thcfe
figns, however, are obferved fometimes in young
women, who have remained barren. Swammer-
dam afcribes this phsenomenon to fterile carefles
or folitary enjoyments : this ftimulus of pleafure
mull make the germ Jburfi: its flrli. -covering and

enter

ORGANS OF REPRODUCTION-- 375

enter the tube, where It foon withers, in confe-
quence of not having received the impreffion of
its fpecific irritant.

The germ which enters the tube, and which as
yet appears under the form of a mucous body, de-
fcends along the tube, and proceeds into the
uterus, where it remains and acquires develop-
ment.

Sometimes the fecundated germ, inftead of en-
tering the tube, defcends into the abdomen and
there expands : the germs have been found alfo to
develop themfelves fometimes in the ovarium, or
•in the uterine tube ; and in all thefe cafes parturi-
tion, by the ufual parages, becomes impoffible.

The development of the foetus appears at firft to
be flow J but it feems afterwards to increafe in the
ratio of the volume which it acquires. At the end
of the firft month, it is fcarcely a few lines in
length ; but towards the end of the fecond it is
nearly two inches ; at three months it is three or
four ; at four months five or fix; at five months
fix or feven ; at fix months eight or nincj at feven
months nearly half a foot ; at eight months from
fourteen to fifteen inches ; and at the period of
birth it is eighteen inches. All thefe dimenfions,
however, are liable to much variation.

The chorion, which at firft has a cottony ap-
pearance, the amnios which fecretes and contains
the liquid in which the embryo floats, the placenta

B 4 which

376 VITAL Functions.

which is attached to the fides of the uterus ta eix-
tra6l juices from it, the umbilical cord which efla-
b])fhes a communication between the fcetus and
the placenta, all expand fimultaneoufly, and in-
creafe in the fame proportion as the fcetus.

As the embryo develops itfelf, the parts which
compofe it can be diftinguifhed. Thus when it is
nearly an inch in length the head forms the half of
its volume J the eyes are marked by two black
points, and the place of the mouth is indicated by
a broad tranfverfe fifTurci the four limbs arife
from a fmall fhort trunk, and are very near each
other; but as it increafes, the form of the parts is
better defined, and they gradually approach that
type which they are deiiined to retain.

When the foetus has acquired a certain fize,
and the placenta has attained to a fort of maturity,
the uterus which is flrongly diftended contra(5is;
and by a fimultaneous ad ion of that organ, of the
diaphragm, and of the mufcles of the abdomen, tlj^
child burfts its coverings, and ifilies, in general,
with the head forcmofi:, and the face towards the
facrum. After it comes forth, the uterus, which
flill continues to contract, expels^the placenta and
its appendages.

After deli\ery, the uterus flowly returns to its
former (late; its tides. decreafe in thickr.efs ; dur-
ing its contradiion it excretes a liquid at lirft fan-
guinolent and then ferous, which gradually dimi-

nifhes ;

ORGANS OP REPRODUCTIOlsr. 377

nifties; and this organ by little and little is reflorcd
to its former condition.

94. But towards the breads another feries of
phaendmena, no lefs important, foon takes place.
Thefe organs, which during geftation remained in.
a fort of continued turgefcence, fwell up, become
painful, and a fecretion of milk begins to be efta-
blithed.

The relation which ex ifts between the uteruS
and the breafts can be explained neither "by the
diflribution of. the nerves nor by that of the veflels,
Thefe organs, in their refpe6live functions, tend
towards the fame end ; that is, the nourifhment of
the child. This common property renders them
dependent on each other, and when they enter
into ad^ion, caufes them to have a reciprocal in-
fluence.

The arteries diftributed to'^the breafts fur nidi
the materials neceliary for the fecretion of the
milk. There is no fufficient reafon for believing
that the organization here follows its habitual
courfe, and that this fluid arifes from the chyle.

At the period of lactation the breails fwell ; the
arteries are dilated, and eaiily fupply the quantity
of blood neceflary for the fecretion of the milk;
and the materials which have not been employed
for that fecretion return by the fanguiferous veins
and the lymphatic veiTels, the latter of which are

exceedingly

S78 VITAL FUNCTIONS,

exceedingly numerous, as in all the fecretory
organs.

On the lecond or third day after delivery, the
fecretion of the milk is completely eftablifhed.
This new fundiion is announced by a general
change of ftate, a fort of febrile crifis, more re-
markable in women of a weak conftitution.

The fecretion of the milk, in general, takes
place fpontaneoufly ; but the greater part of this
fluid is fecreted while the child fucks.

That the milk may be fecreted in abundance
and with facility, the mother muH: be placed in a
particular and habitual fituation ; the muft have an
affedion for the child ; and the latter muft: have
acquired the habit of ftimulating the breaft by a
proper mode of fucking*.

When a nurfe prepares to fuckle the child, (he
Ibmetimes experiences in the breads a fort of or-
gafm or turgefcence; and fhe has a fenfation as if
fbmething were proceeding towards them^ which
induces her to ftiy that the milk afcends.

In young women, and even in men, a fecretion
of a fort of ferous matter, more or lefs abundant,
but which does not exhibit the qualities of good
milk, has been fometimes produced in the breails
by repeated fucking. The quantity of milk fecret-
ed is not proportioned to the fize of the brcafts,

^ See BordcUi TrakS de^s Glandes,

but

ORGANS OF REPRODUCTION. 37^

but to the vital energy of the gland which effects
the fecretion.

The beft milk is that fumifhed by a healthy
nurfe of a gentle difpofilion, who leads a tranquil
life and ufes proper food.

All fudden derangements which take place in
the organization, produce changes in the quality
of the milk. Whenever the fecretion of the breafts
is diiiurbed by any caufe whatever, it is obferved
that its produdl becomes aqueous, and that it ac-
quires a ftimulating property, often very remark-
able, on the digefrive organs of the child : the
latter then experiences colics, or is feized with
purging.

I have often had occafion to remark, that when
the fun(5tion of a fecretory organ is deranged, its
proda<5t exhibits ftimulating properties of greater
or lefs ftrength.

Several phyficians have imagined that the pur-
gative property of certain rriedicines is conveyed
from the mother to the child, becaufe the latter is
fometimes purged when the nurfe takes any laxa-
tive fubftance; but this phaenomenon arifes merely
from the fecretion of the milk being difturbed in
confequence of the general derangement produced
by the purgative. The child may be purged
when the mother has experienced great fatigue,
a violent fit of paffion, or any caufe of derange-

menl

3g0 VITAL FUNCTIONS.

ment whatever. The child is the more fenfible to
the different alterations of the rnilkj the vve*ker
and more irritable it is ; but when robuft, and
when its gatiric organs are in a good ftate, it is
Bot eafily afFedled by the changes which may
take place in the quahty of that i^uid.

The fecretion of the breafts is difiurbed alfo
when the uterus experiences a new mode of ac-
tion. It frequently happens that a fiirong nurfe,
of a fanguine temparament, experiences the men-
Urual flux during iacStation : it is then firft ob-
ierved that the milk flows more abundantly ; that
it is clearer, and that it produces an irritating ac-
tion in the digeftive apparatus of the child : but
this effe£b is only momentary, and the milk foon
refumes its former qualities.

When a nurfe becomes pregnant, her milk is
at firft fomewhat turbid^ but it foon returns to its
former ftate ; it is only obferved that it decreafes
in quantity as geftation advances, fo that a nurfe
may, without inconvenience. Continue to fuckle
during her pregnancy, as long as fhe is able to
undergo the labour without fatigue.

When any coniiderable derangement is pro-
duced in the organization, or in the nervous ac-
tion, or when a febrile ftate takes place, the
breafts fink down, and the fecretion of fhe milk
is often fuddenly fufpended.

95. PhilO"'

ORGANS Off REPRODUCTIOIT. 381

95. Philofophers have at all times made re-
fearches to afcertain whether the human race has
dercended from one fpecies, or whether there were
originally feveral ; and if this was the cafe, of
what kind they were. It is probable, that a great
deal will be written on this queftion, before it be
reiblved. I fhall therefore only offer a few re-
fiedrions on the fiibje£t, which will ferve to give
the reader fome idea of vvhat nature it is.

The claffification of organized beings is not a
matter of abftradlion and convention: orders and
genera exiil for plants, independently of all fyfl:emi
and method, iti what botanifts call the natural fa-
milies ; and the greater number of vegetables are
arranged in thefe families.

Naturalifts ought to enter into an agreement to
comprehend, under the denomination of genus, all
individuals /i{fceptiMe of co^puJatmi and reproduc-
tion, as the etymology of the word feems to in-
dicate. There could then be no difpute in re-
gard to the fignification of this tei'm, fince it would
only be the expreflion of a fa<5l which might
cafily be verified.

The individuals of a genus, which exhibit parti-
cular chara6lers, and which are fufceptible of
.being preferved by means of generation, compoie
a fpecie&s

When individuals of two fpecies of the fame

genus

382 VITAL FUNCTIONS.^

genus copulate, the refult may be a proda6l with-
out a perfedl refemblance either to the father or
to the mother, and having new characters. If
thefe characters are preferved by generation, the
individuals which exhibit them conftitute a new
Ipecies. On the other hand, if they be effaced,
and if the individuals of the fecond race refume
the chara6ters peculiar to the firil: progenitors,
they are called varieties, or nmjiefe. in the lafl
place, when the products of two different fpecies
cannot be perpetuated they are called hyhrides or
mules. Thus man, in regard to the colour of the
fkin, exhibits three diftinft fpecies (the white, th&
yellow, and the black), fufceptible of being pre-
ferved in all climates.

It is known that certain peculiarities of organi-
zation, , which have taken place accidentally or
in confequence of the long continued influence of
climate, of nourifhment, of habits, or of many other
unknown circumftances, may be afterwards perpe-
tuated by generation ; fo that it is poflible there
may originally have been only one human fpecies,
and we are difpofed to believe that it was ex-
ceedingly beautiful ; but the man of nature, like
the pear-tree of nature, was a wild being, fuccef-
iively improved by culture and grafting.

96. In my opinion, it would be difficult to de-
termine.

ORGANS OF REPRODUCTION. 383

termme, at prefent, which was the firft breed of
the canine race ; and I do not think that any one
ever ventured to fay, that we may fee it in the
fineft dog of the Daniih breed. The fineft and
moft beautiful dogs and horfes refemble the cul-
tivated pear*»lree and the civilized man.

The promptitude with •which all thofe fpecies
or varieties of dogs which we daily fee have been
produced, is a circumftance very remarkable. A
moment's refledion on the caufes which concurred
to produce them will furnifli valuable fads, for
enabling us to comprehend what may take place
by the effed of croffing breeds.

In a large city, fuch as Paris, there is an immente
multitude of dogs of all kinds, which are modified
in a thoufand ways by varied mutilations, by the
life made of them, and by the kind of life t0
which they are fubjededj, &c. Thefe dogs are
always wandering about, and copulate without
regard to colour, fize, or quality. Thefe conti-
nual mixtures, fo often repeated, have produced
numerous fpecies and varieties, the primitive types
of which it is now impoflible to diftinguifh. Among
thefe numerous fpecies, fome remarkable for the
greatnefs or fmallnefs of their fize, their plump
or flender form, and the great variety of their co-
lour, have foon been obferved. It would be re-
marked, alfo, that fome of them fhewed more
3 ' aptitude

S84 TITAL FUNCTIOJJ-S.

aptitude for certain things, and greater intelli-
gence in certain exercilt.\'<. - Thole which people
withed to procure would then be feparated, and
made to copulate with their fellows ; the qualities
for which they leenied to have the greateft apti-
tude would be cultivated ; and in this manner
would be obtained the fhepherd's dog, the dif-
ferent dogs for hunting, and even fmall lap-
dogs. The fame number of fpecies arc not to be
found among horfes, becaule the breeds have not
been crofled in fo varied a manner.

By continued copulation between fele6l indi-
Yiduals, that apparent equality which feemed to
prevail between thofe of the fame genus is foon
deftroyed ; and every fine fpecies, fulceptible of
being preferved without alteration, when care is
taken that they may not be degraded by any mix-
ture with individuals of an inferior quality, are
obtained. Thefe fine fpecies really form noble
breeds ; and it is always obferved, that it is chiefly
by the females that the qualities of thefe fine
breeds are perpetuated.

Thus, in Arabia, between Bagdad and BafTorah,
feveral breeds of horfes, diftinguiflied by charac-
ters well known to amateurs, are carefully pre-
ferved, without any mixture. The birth of the
individuals produced from thefe breeds is attefted
by a public adlj which particularly mentions all

the

ORGANS OF REPROUUCTION. 385

the maternal genealogy, and ferves as a patent of
nobility to the animal ; but this nobility is tranf-
mitted and preferved only by the females, the no-
bility of the males being merely individual *.

Species ftill finer would, in all probability, be
obtained by croffing the moft diftinguithed breeds;
for by preferving them without mixture, they are
not only prevented from being improved, but
muft even be fenfibly altered in the courfe of
time, in confequence of many particular circum-
ftances.

But, however this may be, all thefe ideas, in
regard to the nobility of horfes, are much more
rational than thofe which ferve as a bafis to the
nobility eftabliihed among animals of a fuperior
order.

97. Among men analogous circumftances have
produced timilar efFedls. The inhabitants of the
different countries have been flowly modified by
the influence of climate, nourifhment, exercife,
habits, civil and religious cuftoms, &c. When
the population in a diflri($l became too numerous,
men united in fociety, and when they attained to a
certain degree of civilization, they attempted emi-
grations, and made war on diflant tribes, who by

* See jfournal de Ph^jijique, torn. 1.

VOL. Ill, 2 c circum-

386 VITAL FUNCTIONS.

circum fiances, often very different, had been mo-
dified in another manner. Individuals of different
varieties would thus be united, and their mix-
ture muft have produced a new fpecies. Events of
this kind were fo often renewed, that the numer-
ous fpecies and varieties now exifting mull have
been the neceffary refult. But among thefe dif-
ferent fpecies, fome were found to polTefs a very
evident fuperiority of organization, and fhewed ^
more rapid progrefs towards improvement : others
retained remarkable charadlers of inferiority and
degradation ; fome alfo feem to have been check-
ed by circumfiances of climate, food, drefs, &Co
and are nearly in the fame ftate as that in which
they exifiied a thoufand years ago.
- Amons: the different races of men, there are
three, in particular, which exhibit very diflin(5t
chara<2ers and a very remarkable organization.

lit. The v>?hite race, which have a white {km,
tall ftature, head oval, cranium well expanded,
the nofc lengthened, the facial angle eighty- five
degrees, the hair fine, commonly of a chettnut co-
lour, and which are in an advanced flate of im-
|)rOvement.

ad. The tawny race (Mogul),- which have the

ikvn of a copper-yellow colour or tanned, the face

broad, the eyes a littk towards the fides, the

cheek bones proje{3ing, the nofe flat, the chin

^ {harp-

ORGASrS OP REPRODtJCTIOl*?. 387

ftiarp-pointed, the hair thick, flat, and black,
Hature fliort, cultivation lefs advanced. This race
inhabit the greater part of the globe, and are
found in almoft all climates ; but more particu-
larly in a great part of Alia, in America, in the
iflands of the South Seas, and as far as the frigid
zones.

3d. The black race, which have the Ikin of a jet
black colour, the flature long and flender, the
hair fhort and woolly, the forel/ead flat, the nofe
flat, the jaw bones proje£ling the lips thick, a
great mobility of face. They inhabit Africa.

The colour of the flcin, which Turn ifl:ies the
moft fl:riking charader of thefe three races, may
have been the fefult of the long continued influ-
ence of climate ; but, in the courfe of time, it
aflTumed an organic charadler, which is preferved
without alteration in all latitudes.

98. The mofl: remarkable phasnomenon in the
a<5l of reprodudlion is the tendency which the
generating individuals have to tranfmit, not only
the peculiarities of their organization, but alfb
a difpofition to certain difeafes to which they
were fubjedl, or an aptitude for certain facul-
ties, which they had acquired. This property
daily contributes to the degradation and improve-
ment of the fpecies according to alliances. ,

51 C 2 It

388 VITAL FUNCTIONS.

It is of importance to repeat, alfo, that the in*-
fluence of the mother is more remarkable on the
eflential and interior organs of the child; that
the influence of the father appears chiefly in the
exterior and acceflxDry parts ; and that, in general,
the fpccies is improved by croffing the breed.

RECA-

[ 389 ]

RECAPITULATION

OF THE KNOWLEDGE ACQUIRED IN REGARD
TO THE ORGANIC FUNCTIONS.

99. The vital power, like that of affinity and
attradlion, is univerfally difFufed. It is completely
exercifed only on organized bodies at a certain
degree of thermometric, hygrometric, and elec-
tric, &c. temperature j and by a continuity of ac-
tion on flips or fecundated germs arifing from
thefe bodies.

When an organized body is thus properly fub-
jefled to the vital power, it pailes through a le-
ries of phenomena which conda6l to a fort of
maturity. At this period, its parts, which are no
longer in a proper relation of organic ftrudldre,
remain completely fabje-l to the power of affinity,
which combines them according to its peculiar
manner, and caufes the remains of its decompo-
fition to return into the general grand circula-
tion.

Organized and Hving bodies are not completely

free from the influence of the force of affinity ;

but the latter being lefs powerful than the vital

a6lion, does not begin to manifeft itfelf by any

205 pbasnemena

SQO VITAL FUNCTIONS.

phaenomena of decompofition, until the vital '
power becomes too weak^to retain the moleculae
of matter in a proper ilate of organic ftru(5lure.

The fi:rr.6lure of every organized body feems
to confift in a vafcular reticulation, in the midft
of which matter^ by circulating, may afTume that
indefinite degree of divifibility, necellary for main-
taining the phacnomena of nutrition.

Thofe organized beings which appear to be
limpleft, fuch as vegetables and zoophites, have
at leail: fyflems of nutrition and of reproduc-
tion. Thefe two fyflems are not concentrated,
but multiplied and difleminated throughout all
their different parts. This difpofition permits
thefe beings to be divided into feveral portions,
which increafe and multiply feparately.

But in proportion as we afcend towards be«.
ings of a more compound organization, it is ob-
ferved that the fyftems of the organs increafe, that
they ceafe to be multiplied, that they are con-
centrated and diflind, and that the living body
can no longer be divided without perifhing. Of
all animals, man appears to have the centres of
his organs moft clofely connc6ted.

Iji living bodies the vital power caufes parti-
cular functions, which depend on their organic
mode of ftru dure, to be executed; but it main-
tains in them all a common and uniform a(Siion,

which

Ki;CABlTULAT.ION. ggj

which conftitutes the efletitial pbeenomenon of
life. It is indeed obferved, that all the molecule
of matter which compofe thefe beings are in a con-
tinual flate of motion, during which they are
driven off, and their place is gradually fupplied
by others, which afTuine a different arrangement,
remarkable at the different periods of their life. :

The extreme degree of divifibility or decom-
poiition to which matter may be brought in the
organs;, its converfion into the proper fubflance
of thefe organs, the place of which it continu-
ally fupplies "with different modifications, are phse-
n.omena, the mode of which is unknqwn to us
becaufe it efcapes our obfervalion.

If we reflect, for a moment, that we obferv€
animalcula not mor^ than the two or three hun-
dredth part of a line in magnitude^ which are ge-
nerated, ir^creafe, move, and reproduce them-
felves; that it is probable that in each j?oint of
the organization of thefe beings changes are ef-
fedted, in a manner analogous to thofe of the
greatell living bodies ; that it appears that matter
in both affumes the fame degree of divifibility,
^nd that nutrition is pei:forraed with organic in-
flruments of the (ame fize,:_U, may readily be
conceived how far our eye, armed with the belt
inftrument yet knov/n, is from being able to pene-
trate thither in order to obferve what is taking
place. Thus, the phasnomenon of nutritition is

2 c 4 con-'

392 VITAL FUNCTIONS.

concealed from us in that infinite minutencfs,
which is beyond the reach of our coarfe organs,
fo that we are acquainted only with the refults of
that operation.

Living bodies, independently of their organs
of nutrition, are provided alfo with parts fpeci-
a1]y defl:ined for receiving the impreffion of ex-
ternal objects. Thefe fyftems of the fenfes, the
form of which varies, always conftirute an organ
of touch, more or lefs extenfive and delicate;
and this organ is conftantly found even in plants.

Every organized being has the power of placing
itfelf, in the furrounding medium, in that pofi-
tion which is moft favourable to its organization ;
and it is indeed obferved that vegetables pufh
their roots towards the moid earth, and turn
their ftems towards the lights as animals fearch
for thofe fubflances which are propereft for their
nouriQiment. *

A flate of fuffering or of eafe is remarked in
all living bodie?, and even in plants : to the ob-
ferving naturalift, the appearance of a vegetable
which fufl^ens, or which acquires a vigorous deve-
lopment, is as exprcffive as the cry of fatisfaftion
or of pain e?nitted by an animal.

When the functions are not performed in a
proper manner, for want of thofe things which
are nrceflary to the fupport of life, there takes
place in the organization a ftate of change, which

confti-

• RECAPITULATION. 3Q3

conftitutes the painful fenfation : it is the fii ft
which animals feem to experience.

This fenfation of uneafinefs or of want excites
animals, in an irreliftible manner, to adiofi, for
the fike of their own prefervation, and for the
propagation of their fpecies. ' The fenfation of
eafe which they experience, in fatisfying this want,
becomes afterwards a itimulus, which excites them
to the repetition of the fame ad.

The adion of foreign bodies on the oi'ganiza-
tion may produce a change of ftate analogous to
want, and thus give rife to a .painful fenfation,
which the animal is powerfully incited to free it-

feif from.

In proportion as an animal expands, experi-
encing alternately painful and agreeable lenfa-
tions, it becomes fit to appreciate flight and
tranfient changes of ftate, which in fome mea-
fure are indifferent to the order of the fun<5lions.
Every thing that ftrikes'the organs of the fenfes
may prqduce fenfations of this nature.

In animals, the organic fyfi:ems, by habitual
^xercife foon contra(il a great aptitude for dif-
charg'ng the functions peculiar to them. This
aptitude is flill increafed by the reciprocal aid
which they lend to each other in their indivi-
dual and fimuUaneous adtion.

The faculty which the organs have of receiv-
ing external irnpreilions, capable of producing a

change

3g4 VITAL FUNCTIONS.

change of ftate which conftitutes fenfation, is an
organic function, which by exercife and the force
of habit becomes ftill fufceptible of being per-
formed with more facihty or fpeed.

Thus a fenfation produced feveral times in
au organ of the ienfes, by the impreflion of an
external body, may be afterwards completejy
renewed, without the prefence of that objedl,
merely by that of any accefibry circumftance^
which accompanied it and which is renewed.
From this it refults, that the fenfations experi'
enced are not entirely loft, though they be ef-
faced, lince they can be thus renewed by aeeef-
fory circumftances, and even be recalled in fuc-
ceffion, according as they are more or lefs inti-
mately connected. This faculty, which is ob-
ferved in all animals, in a greater or lefs degree,
furnifhes the principal means of improvement.

An animal, indeed, which is continually excited
to a(^ion, in order to fatisfy its wants, and whofe
paft fenfations may be repeated in confcquence of
new fenfations, finds itfelf poflefied of futScient
means for comparing thefe different fenfations, for
comhining them, and for thus forming a judgment ,
in confequence of which it determines to ad in a
manner belt fuited to its prefervation.

If to this be ftill added, that the animal has a
ilrong tendency to a(Sl by imitation and by the force
of habit, and that the modifications which refult

from

RECAFITULATTOIT. 3Q5

from the varied ufe of thefe faculties may be
tranfmitted, at leafl in part, by the way of gene-
ration, we {hall have the fa m of the means which
concur to the produ61ion of organic phsenomena,
and which tend^tp the progrefs of improvement.
Every animal, indeed, is fufeeptible of individual
improvement, more or lefs extenlive, and in this
manner acquires a fort of experience.

I GO. The different iyftems of organs in man,
taken together, form a being, who can move
from one place to another, and place himfelf in
relation with every thing around him. His organs
of the fenfes render him fentible to the impreffion
of the light, either diredl or reficdled ; to that of
the air in a ftale of vibration, and of odorous and
iapid moleculse ; and to the contatl of all bodies
of a certain mafs and denfity. By means of a
Very extenlive fyflem of organs, he affimilates to
his owtf fuhftance atmofpheric air, water, and all
materials ariiing from organized bodies, in the
laft place, he reproduces hunfeltj by the con^
courfe of a collection of parts, which are in two
feparate individuals.

AH thefe fyftems of organs, exceedingly various,

are effenlially formed of veflels aud nerves, having

commdn centres on which their continual a(51ion

depends J 1<) that the organization is compofcd

.'4*iS/ '^n* of

3g5 VITAL FUNCTIONS.

of parts, which conftitute a whole necefTarily
continued. The veflels and nerves, by their varied
and numerous interfeclions, form different tiffues
of organs.

The interior parts of the vefTels and the cells,
refulting from their different tiflues, contain ferous
and fanguine fluids ; albuminous, gelatinous,
adipofe, faline, &g. fubftances ; and, in general,
every organic material of which the veffels and
nerves themfelves are formed. All thefe fub-
ftances are continually penetrated and traverfed
by eleftriciiy, light, caloiic, &c.

Each point of the organization may be confi-
dered as a fecretory organ ; the parts in their con-
tinued adion experience a change of ftate more
or lefs remarkable: after having acquired their
full development, they gradually lofe their pliabi-
lity ; matter is accumulated in them ; the conti-
nued motion of fecretion and abforption is no
longer performed with the fame aflivity ; the or-
ganic moleculss move in them only in a flow
manner, and at length arrive at that f^ate of reft
which conftitutes death.

The whole of thci organization may thus be
conceived as confined to a life merely vegetative
or animal, in which each point arrives at a certain
degree of development, of maturity and death,
by a continuity of motion and fJicretion. Thus,

in

RECAPITULATION'. ^Qj

in fome cafes of very exrenfive palfy, attended
with imbecility, man is reduced to an analogous
exiftence, entirely deprived of relative life.

In this cafe, the exiftence feems to be main-
tained only by the ganglions of the trifplanchnic,
by means of the nerves of that apparatus, which
accompany all the veflels, and which are diftri-
buted to the principal organs, not fubjed to the
empire of the will.

But each point of the organization, independ-
ently of its particular life, enters into the compo-
lition of a lyftem, which performs its fun6lions
only by means of the particular nerves which pro-
ceed to it from the brain, or from its vertebral
prolongation. In a word, the fimultaneous ac5lion
of the different fundions produces the beautiful
phaenomenon of the human organization.

In this phaenomenon, it is of importance not to
forget, that each organ is elientially an inftru-
ment of fecretion ; and that in the exercife of
this funftion, the arteries fupply the materials and
the nerves the principle of a6lion. The heart
and the arteries, by their continual contradion,
propel the blood to every part of the body ; this
movement is maintained by the prefence of the
blood in thefe parts, and by the influence of the
nerves which are diftributed to them. The ce-
rebral organ, being itfelf an organ of fecretion,
requiresvfor the exercife of its fun6tion a conti-
nual

ZQB VITAL FUWCTI:ONS.

Dual fupply of arterial blood ; fb that thefe two
principal organs of life have evidently a mutual
dependence on each other.

The organs, in confequence of the different
excretions, are continually fullaining a lofs : this
lofs is repaired by means of fubflances conveyed
to them from without ; and for this purpofe the
organs are in relation with all external bodies.
Hence it is obferved, that they are differently
affected according as the objedls which ftrike
them are favourable or hurtful to the whole phas-
nomena of the functions.

In man, as well as in animals, the change of
flate which takes place in the organs, by the im-
preffion of objects, which tend to difturb or to
maintain the order of the functions, conftitutes
the painful or agreeable fenfations. The impref-
fions he receives may be completely renewed,
without the prefence of the objeft from which
they were firft received, but only by that of fome
acceilbry circumftances connected with it. By
thefe means, he acquires the faculty of avoiding
obje6ls which have produced in him fenfations
deftru6live of his organization, and of placing
himfelf in circumflcinces favourable to his prefer-
vation. The combined exercife of thefe firtt fa-
culties, and the exteniion of them, give rife to
the development of the underftanding.
'■ The fyllems of organs are of three orders : ift.

Of

RECAPITXTLATION. 399

Of relation : 2d. Of nutrition : 3d. Of repro-
dudlion.

1 01. Man^ in confequence of the ftrudure of
his limbs, tranfports himfelf from one place to
another ; removes from objedls which hurt him,
and aproaches thofe which are favourable to him.-

Of all the mammalia, he has, without doubt,
the mod advantageous form, as properly fpeakirlg
he is the only biped, which enables him to pre-
ferve with facility a vertical pofition, by placing
the whole fole of his foot on the ground, and ex-
tending completely his ham. His pelvian limbs
are provided with large mufcles, and the fwelling
or dilatation produced by thefe mufcles exclufiveiy
in him, add to the beauty of his fhape and to the
flrength of the parts.

The thoracic linibs are not impeded by walk-
ing ; and may hie employed for the nobleft and
moft important purpofes.

His head is almoft in eqUilibrio on the vertebral
column, and his eyes are turned dire6lly forwards.

The difpofition of the mufcles allows the limbs
to perform the moft varied and moft ejttenfive
motions; and it is aftonifhing to fee with what
force and agility thefe motions are performed by
fome perfons, in confequence of a peculiar or-
ganic difpolition and proper exercifs,

3 Th»

400 VITAL FUNCTIONS.

The ilrength and pliablenefs of tumblers, tlie
lightnefs and agility of dancers, the furpriling
quicknefs of the fingers of the organifi:, are al-
ways the more aftonifhing, as the anatomical
iftrudiire is not fufficient to account for it.

The mufcular Itrength, difplayed by fome in-
dividuals of an athletic conformation, and the vio-
lent action of the mufcles in certain ftates of
paffion or of difeafe, evidently fhow that an ex-
planation of the phaenomena of life are not to be
fought for in the laws of natural philofophy.
Meao;re and debilitated females are often feen
to break the ftrongefl cords, and to drag after
them enormous mafles, during paroxyfms of hy-
fterics, or of mania. A mufcle may then over-
come a refiilance by which it would be broke in
the ftate of death.

The mufcular tyflem abfolutely requires employ-
ment : it appears to be that vihich confumes, in the
manner moll proper for health, the quantity of that
principle of a6lion which the brain diflributes to
every part of the body by means of the nerves.
The habitual inactivity of this fyftem always pro-
duces greater or lefs derangements; it is one of the
moft frequent caufes of the chronic difeafes which
prevail among the idle claffes in large cities. The
habitual exercife of the mufcular fyllem confumes
the llrength more than that of any other ; and
* therefore

HECAPITULATION. 401

therefore men continitally employed In fevere la-
bours are the lead proper for any other funftion.

The mufcleSj like the other organs, have a great
tendency to exercife the funclion peculiar to them,
at the fame time, in the fame manner, with the
fame degree of intenfity, and in confequence of
the fame recolle(51ed objeSs : this couditutes
habit.

The tendency to habit, which allows the repe-
tition of the fame a61ions with more promptitude,
addrefs, and facility, is one of the great (iaufes of
improvement.

/

102. As the -organs, of the fenfes bring us into
a more dire6l relaitiein with the furrounding ob-
jeds, thefe objects, by their varied a6lion on our
organs, unveil to us a part of their properties.

103. Man fees illuminated objed^s of a certain '
lize, and at. a certain diliance, by means of an or-
ga'n, the conftrnftion of which is lim.ilar to that of
the camera obfcura. The luminous rays refle<5ledi
from objects and refrad:ed by the humours of the
eye, proceed to the retina, and there trace out the
image of it, in an inverted polition.

The fenfation which the individual experiences
by the impreffion made on the retinp, is not that of
an image painted in the bottom of the eye ; for in
that cafe another eye would be neceflary to look at

YOL. HI. ID it;

4CKi VITAL FUNCTIONS.

it ; nor of an objecfl inverted which i^ places in its
proper pofilion ; for he has no idea of up or of
down, nor of right and left of his retina ; but a
fenfation of touching, which refuUs from the con-
ta6l of the different luminous points with the
retina, in an order determined by the form of the
objed.

The fenfation of fight is the moft important,
lince it brings man -inftantaneoufly into relation
with very diftant objedls ; but it is alfo the mod
uncertain fenlation.

Sight indicates only the form and colour of bo-
dies : it is by approaching and touching them that
we can judge of their diftance and magnitude ?
and, notwithftanding our daily experience in this
refpec^, it often leaves us in a ftate of uncertainty,
from which it is impoilible for us to free our-
felves. ,

The rays of light, in their progrefs to the eye,
follow all the common laws of dioptrics ; and there
is no difference between the eye and an achroma-
tic telefcppe, except that the former is a living in-
ftrument, lufceptible of being moved in every di-
rection, and of being lengthened or fhortened to
change its focus. .

At the moment when the impreiTion of the rays
of light on the- rctjpa- begins to be felt, the eye
can no longer be compared to an optical inftru-
m.ent, It is not becaufe an image of the objed. is

painted

RECAPITULATION. 403

painted in miniature on this nervous membrane
that wehaveafenfationofitjbutbecaufein painting
itfelf there^ each luminous point produces an im-
preffion of conta<51, which is communicated to the
common centre of fenfations in a particular order,
and with a degree of intenlity which varies ac-
cording- to the form of the bodies and the reiiedl-
ing property of their furface : in this refped: the
exceffive fenfibility of the retina is inconceivable.

The organ of fight feems to have a more ex-
tenlive field of view in carnivorous birds than
in man.

104. The organ of hieafing confifts etientially
of a nervous pulp, which perceives the conta61 of
the air in a ftate of vibration. This pulp is found
in the midft of a vifcous fluid, contained in the
membranous labyrinth.

The membranous labyrinth is enclofed in an
ofleous labyrinth, formed in the petrous portion of
the temporal bone. It communicates with the
tympanum by two apertures, one of v/hich is
clofed by a membrane, and the other by a fmall
moveable bone.

This fmall bone is articulated with three others,

the laft of vyrhich is applied to the membrana tym-

pani, and adheres to it. Thefe fmall bones have

attached to them the mufcles by which they are

2 D 2 moved;

404 VITAL FUlSrCTIONS.

moved ; and they flretch the membranes to which
they are affixed.

The membrana tympani fcparates the tympa-
num from the auditory conduit, which terminates
in the exterior part of the ear.

Ail this apparatus, which is very complex, feems
deitined to facihtate the entrance of the vibrating
air into the ear, as well as its contact with the
nervous pulp of that organ, and of fecuring the
1-atler from violent and abrupt impreflions.
■ The impreffion made on the expanfion of the
labyrintbic nerve, by the contaft of the air in a
Hate of vibration, is continued to the brain, and
produces in it the feniation of Ibund.

The fenlibility of the nervous fyilem, which ap-
preciates all the modifications of the air in a Itate
of vibration, is no lets exquiiite than. that of the
retina, which perceives refradled light ; and it is
difficult to conceive how the ear can be fo delicate
as to enable the mufician to diftinguifli feveral in-
termediate degrees between two tones.

105. The f}dlem of fmelling confifts in a mem-
brane of a mucous nature, fiifceptible of being af-
fected by the moleculas of certain bodies held in
folution, or in fufpenlion in the air.

The flrength of fmelling feems to be' in the
ratio of the extent of the olfactory membrane: in

fome

RECAPITULATION. 405

Ibme'carhivofdus animals'this fenfe is exceedingly
acute.

1 06. The organs of tafte are contained in a
mucous membrane, which perceives the imprefJion
produced on it by the contav51 of the moleculfe of
certain bodies, and particularly of thofe which are
foluble in water.

The organ of tafte and that of fmell, in man,
are far from perceiving the impreffion of all the
molecule of bodies which come into conta£t with
them : there are even many which have a very
greaf a61ion on the nervous fyttem, and whofe
contaft with thefe organs produces no fenfation.
The moft violent poifons are frequently infipid ;
and the air charged with miafmata, which produce
epidemic dileafes, is often inodorous.

The fyftems of the fenfes, of which we have
here fpoken, are evidently organs of touching ;
they however differ from that of touching, pro-
perly fo called, in this ref[je<5l, that the latter re-
ceives only the impreflion which refults from the
refiftance, temperature, and form of the bodies ;
while the former experience itnpreffions, which de-
pend on other properties of thcfe bodies.

All parts of the body arefufceptible of being af-

fe^ed by the 'eohtaft of foreign fnbfiMnces, and

tiiufl; be confidered-'as organs of touching; but

' 3 D 3 that

406 VITAL functions;

that which fcems really to deferve this appellation
is the hand, as its ftrufture allows it to accommo-
date itfelf to the form of all bodies, and to exa-
mine with eafe all their prominences. The Ikia
of this part, by the continual exercife of touching,
acquires a great aptitude for perceiving the llight-
eft changes in the form, the contiftence, and the
temperature of bodies. How far the delicacy of
this organ can be carried, when not diftrafted by
the fenfe of feeing, and when continually exer-
cifed in a proper 'manner, may be obferved, in
pfirticular, in fome blind perfons.

As every part of the organization is fufceptible
of being affe61,ed by the contadl: of foreign bodies,
in this point of view they may all be confidered
as organs of the fenfes.

The difference which exifls between the various
parts of the body, depends on the fundions which
refult from their organic itrufture, and from the
nature of the nerves diftributed to them ; according
to thefe differences, the organs anfwer, different
ways, to the impreffions made on them.

When a change takes place in the Hate of an
organ, in confequence of an impreffion received,
this change is always manifefted in the particular
exercife of the function of that organ, which may
be increafed, diminiflied, or altered.

Bodies which hffeh the afbion of an organ may

be

RECAPITULATlOlsr. 407

be called deh'iiitants ; thofe which increafe it may
be diftinguifhed by the appellation of excitants ;
and thofe which alter it may be called irritants,

107. The action of the numerous fubftances,
fufceptible of affecting our different organs, pro-
duces phoenomena exceedingly various.

The impreflion may be confined to the part
which is touched, or be propagated to thfe centre
of the nervous action. If it be confined to the
part touched, it produces only a very flight and
tranfient change of ftate, which takes place, as we
may fay, without the knowledge of the reft of the
organizationi If it be tranfmitted to the centre
of the nervous adion, the change of .fi:ate which
thence refults may occafion a fudden fenfation, or
produce none capable of being appreciated.

In the laft place, the refult of an impreflion re-
ceived by an organ may be fpecially manifefled,
either in the part affe<Sed, or in a diftant organ, or
in the whole of the organization.

But to convey a better idea of thefe different
modes of affection, we fhail here illufbrate them
by examples.

Slight local affedlions, altogether indolent^, and
which feem to have a relation only to the part
which exhibits them, often take place.

Every ftrong and unufual ^impreflion on a part
which receives nerves from the encephalon, or its

2 D 4 vertebral

•408 TITAL FUNCTIONS.

vertebral prolongation^ gives rife to a fudden fen-
fation.

But if the afFeclion takes place in an organ to
which no nerves proceed from the encephalon or
'its prolongation, the impreffion may ttill be re-
ceived, and produce in the organization a change
of (late, often very confiderable, without the indi-
vidual experiericiri'g at firft any very fenfible fenfa-
tion. Almoft all catarrhal difeafes begin in a fimi-
lar manner; the a65:ion of the virus which produces
gonorrhoea is not felt in the urethral membrane at
the moment of infe6tion. Moft epidemic, conta-
gious, and eruptive fevers^ and fev^eral kinds of
afphyxiae, produced by the'adion of m.iafmata con-
veyed into the aerian pafFages, belong to the fame
clafs.

An organ may be afFefted alfo by a body, Vvdth-
out being diredly ilruck by it, in confequence of
the communication ellablifhed between the nerves
and every part of the organization : thus fridion
with mercury excites fecretion of the falivary
glands, without exercifing a perceptible action on
the fkin.

From thefe different confiderations it refults,
that an orsan anfwers to different excitants, in the
ratio of the fun61ion peculiar to it; of the nerves
which are diftributcd thither, and of the nature of
the excitants.

¥/hea a mufcle is irritated, it anfwers by

motion^

RECAPITULATION. 40^

oiotion, as a gland does by the produdl of fecre-
tion.

The ' fyliems of organs which receive nerves
• from the eriG^phalon or from its rachidian prolon-
gation, are eafily" excited, and experience a lively
'and Hidden len'fation. Thofe which have thek
nerves onlv from the ganglions of the trifplancb-
nic are ienfible in a weak manner to the impref-
lions received.

When a f^ftem of organs, eafily excitable, is
ftimulated in a manner proper to the exercife of
that function, the refult is a fenfation of -eafci if
the irritation is of fuch a nature as to diliurb the
order of that fun'ftion, the fenfation is painful.

Organs habituated to painful and agreeable fenfa-
tionSj perceive alfo timple ones, which are, in fome
tneafure, indifferent to the organic order. In a
word, the uneafinefs experienced by organs wh-en
their fun(5iions ftand in need of being exercifed,
and that which refults from various internal de-
rangements, are fo many particular fenfations.

An organ reads with the more facility on an
irritant, when it has already received the imprel-
lion of it feveral times. Thus the mucous mem-
brane of the aerian patTages is ealily affeflicd, when
it has already experienced frequent colds.

The cafe is the fame with the fyftems of the
fenfes : the impreffion produced on them by ex-
ternal obJQcis, is repeated with more facility, wdien

they

410 VITAL FUNCTIONS.

they have already been fubjeffted to them feveral
times. ^

Hence, the organs of the ienfes, the organs of
motion, and thofe even of the different lecretions,
acquire, by habitual exercife, a great aptitude for
repeating, with facility, the acts peculiar to them,
in confequence of the fame excitants.

This force of habit, in regard to the repetition
of the fame a6ls, becomes fo great that a d'lreB Jen-
fatioiz, produced by an objed, may be entirely re-
newed, without the prefence of the obje<5l by
which it was originally communicated, but only
by that of fome circumftances connected with it.

The combination of dire£i fenfatians with recoi-
led edfenfationSj or ideas, is at firll produced by
the irrefiftible impulfe to a5i, in order to withdraw
from pain, and to fatisfy wants. An aptitude for
combination may then be extended to obje6ls lefs
neceffary for prefervatiog.

It is the extenfion of this power of combining
fenfations, which gives rife to the development of
the intellcGLual faculties. la a word, it is by the
almoil exciufive employment of this faculty, that
man attains to tliehigbefl degree of intelligence.

The particular hiftory of the development and
extenfion of the intellectual faculties muft be
foil" 'el on phyfiological knowledge, which can
alone afrbrd a rational balls and fixed point of de-
parture to the metaphyfician.

io8. The

. RECAPITULATION. 4J1

io8. The changes, which are continually ef-
fefted in every part of the organization, conftitute
nutrition, properly fo called. The blood furnifhes
the materials neceflary to the exercife of this
fundiion.

The bjood, during its continual circulation, is
diftributed by the arteries to every part of the
body ,- it then returns by the veins and lymphatic
veffels, to repair its lofTes, to refume its former
qualities, and ^o be fitted for a new circulation.

The blood repairs its lolTes, at the expence of
the prodiiiSl of digeftion : it frees itfelf from its
excefs of aqueous parts by urinary excretion ; it
refumes its former qualities by its pailages through
fome glandulous organs, and particularly through
the lungs. In the laft place, the elevated tem-
perature of the lungs, which is the refult of the
phaenomenon of nutrition, is maintained by means
of the cutaneous organ.

The blood, propelled from the left fide of the
heart, iffues through the aorta, and ditlributes it-
felf, by the arteries, to every part of the organiza-
tion, to which it conveys the arterial blood, the
common principle of all lecretion.

The. blood, in tnis patTage, having experienced
2ilofs and alteration, more or lefs confiderable, re-
turns by the veins and the lymphatics.

The chyle, which mixes itfelf with the venous

blood.

412 VITAL FUNCTIONS.

blood, to rep^ii" its lofles, is the prod u 61 of di-
geflion.

Digeftlon comprehends the phienomena exhr-
bited by the"a1im(irits introduced into the digefiive
iyftem, from the time they enter the mouth till
the period when they iffue from the body, at the
extremity of the large inteftines.

The alimen.tary fubtlances, which are always
procured from animals or vegetables, are maltr-
eated in the mouth and penetrated by the faliva.
By degkition they are conveyed along the cBfopha-
gus into the Itomach, where they are mixed with
new juices, and by the action of the iiomack and
their retidence in a living organ they are tranf-
formed into a chymous pulp. The aliments then
pafs into the duodenum, where they are penetrated
by the bile, the pancrealic liquor, and the intefti-
nal juice, and are transformed into a homogeneous
fubflance, which contains the chyle.

While this fubflance is proceeding along the
intellines, the mouths of the numerous chyliferous
veflels, with which their tides are covered, abforb
the chyle it contains i and when it reaches the ex-
tremity of the large inteftines, the reliduum of the
digeftion is thrown out.

The abforbent veflels of the chyle proceed, af-
ter a fhort palTage, into the glands of the mefen-
tery, where the chyle fiill experiences a particular

change.

RECAPITULATION, 413

change, and then ifTues from thefe glands by
larger and lefs numerous veffels, whieh proceed
in<o glands of a ftill greater fize. At length,
thefe chyliferous veflels are confounded with the
lymphatics, and terminate along with them in two
thoracic du(Sls, which proceed into the fubclavi^ii
veins: the left thoracic du^ is ' always much
fironger than the right, which is fometimes want-
ing-

Such are the pbaenomena of chylous abforption,
perceptible by the fight ; but it is very probable,
that thofe which efcape our researches are much
more important and extenfive.
. There are feveral reafons for believing that the
whole proda6l of digell ion does not proceed into
the fubciavian feins, but that a part is dire6ily
mixed with the blood in fome other way.

The transformation of the aliments into a ho-
mogeneous pulp has at firft a refenjblance to a
chemical operation : it however differs from it in
many points of view.

"When vegetable fubfiances, whether green,
ripe, or already putrid, and animal fubilances,
either raw, boiled, or even in an advanced ftate of
putrefaction, are introduced into the ftomach, th^
action peculiar to them is immediately fufpended ;
their fermentation or putrefaction is checked, and
the vital power makes them pafs through a feries
®f ph;£nomena, the refult of which is the forma-
tion

414 VITAL FUNCTIONS,

tion of a chymous pulp, that in the fame animal-
always contains chyle of the fame nature.

Dupiiiytren, in his ingenious experiments on
the chyle, tried to communicate colour or fmell to
this fluid, by mixing with the aliments colouring
and odorous fubftances of every kindj mineral, ve-
getable, and animal, but his attempts were fruitlefSj
as he was never able to produce the leaft fenlible
alteration.

When the gaftric lyftem enjoys its full vital
energy, none of the phtenomena peculiar to the
fermentation and putrefa6lion of animal or vegeta*
ble fubltances are obferved.

But if this fyftem is gradually weakened, phse-
nomena which evidently belong to the lavs of
chemiftry are manifefled. There are then obferv-
ed a difengagement of carbonic acid gas ; of
falphurated and phofphorated hydrogen gas; of
gafeous oxide of carbon, &c. ; the formation of
acids and alkalies j and, during fome difeafes, the
fmell of the faeces indicates a very evident com»
mencement of putrefa6lion in the intefiiines.

Digeftion is neceffarily a very important func-
tion, (ince it comprehends the acftion of the mouth
and of its glands, of the osfophagus, of the fto-
mach, of all the intellines, of the liver, of the
fpleen, and of the pancreas. All thefe organs ex-
ercife an almoft limultaneous adiion, and with d
great exertion of power^ Hence it happens that

people

RECAPITULATION. 4i5

-people after meals experience To often drowfinefs
and fatigue.

Children, who in general are exceedingly vora-^
cious, lleep when their flomachs are full ; and it
is obferved that great eaters generally take a nap
after dinner.

As digeftion affords a very lively mode of gra-
tification, it was natural for men to make this
fbnclion a fource of pleafure ; and it is indeed re-
marked, that the table, among all nations, forms
one of the greateil fources of enjoyment.

It may here be obferved, that the whole of the
organization, in the three orders of organs of
which it is compofed, exhibits three very different
fources of enjoyment.

The firfl is found in the fyllem of the fenfes, in
conjun6lion with the intellcdtual organ ; the fe-f
cond in the digeftive organ ; and the third in the
organ of generation.

The firft order of organs do not become a
fource of happinefs till the period of mature age;
and only among civilized nations, who have given
them a proper direction and cultivated the ufe of
them.

The lafl develops itfelf at the adult age, often
with great force, and imperioufly requires to be
exercifed ; but in old age, the action of the geni-
tals becomes weakened^ and is often completely
annihilated.

I The

4lQ VITAL FUN"CTION-S.

The digeflivc fyflcm affords pleafnrc at all sges:
it is the only fource ofenjojinent in children^ who
feera to live only to eat. In the adult age, the
intelledlual funcSiions and thofeof the genitals im-
perioLiIly require to be exercifedj ihe fun(?tion of
thefe tyftems, which is then executed with great
intenfit)^ renders that of the gadric fjiiem of little
i-mpoi-tance ; but in the courfe of years the ftomach
refumes the afcendancy, and it is the only enjoy-
iTient of many oid perfons, who appear in various
refpe6ls to return to the ftate of childhood, and
to-acquire again its prevailing talles.

The intelledual fim^lions are thofe^ in general^
vjfhieh continue longefl; they can retain their
vigour and even acquire ftrength during the-
whole courfe of life, when properly cultivated and
in a continued raanner.

If is however obferved that a derangennent of
the princi'pal vital organs always produces a pro-
portional weaknefs in the intelledlual funftions.

The object of digeftion is to furnifh the quan-
tity cf chyle, necelTary for repairing the lofles
which the blood experiences in the courfe of its
continual circulation, by fupplying materials for
ditlerent fecretions.

In perfons who lead a very active life thefe lofles
are coniiderable : cutaneous and pulmonary per-
fpiration, urine, and other excretions are always
very abundant. Such perfons have an extra-
ordinary

RECAPITULATION-. 41^

Ortiinary appetite, and eat a great deal without
being incommoded.

On the other hand, there are found In large
cities women of an indolent charadler, brought
up amidft luxury and eafe, who have fcarcely any
excretions. All their organs are reduced to a
fiate of inadiion and debility, which feems to be a
mean term between life and death. Thefe per-
fons have habitually very little appetite, and ufe
only a fmall quantity of food.

The flomach, like the other parts, is ilrengtben-
ed by exercife ; habitual excefs of aliments may
caufe it to acquire great amplitude, and In this
manner render it the predominant organ. It is
not uncommon to meet with men who eat a great
deal, though they take little exercife ; the greater
part of the vital powers In fuch perfons are em-
ployed in digeftion. Perfons, in general, who are
exceedingly corpulent, are feldom endowed with
great llrength of intelleft.

When the ilomach is overcharged, it makes a
continual effort to digeft the aliments which fur-
nifh ufelefs chyle. If its weaknefs be fuch as to
prevent it from efFe6ling digefiion, the alimentSj,
being then abandoned to the laws of affinity, be-
come to the alimentary canal a ftimulus, which
excites vomitins: or diarrhoea with violent efforts
and dreadful colic Sometimes they produce fpaf-

voL. III. 2 E modic

418 VITAL FUNCTIONS.

modic afFedions of different kinds, convulflons,
and even death.

Too frequent abufe of the gaftric organ and
ina61ivity of the mufcular fyftem are the mofi:
common caufes of the chronic difeafes which are
obferved in large citie&.

109. The blood is freed from its excels of
aqueous parts and from different faline fubftances
bj the urinary fyftem.

The mod extraordinary phsenomenon which
occurs in the function of the veins is, the promp-
titude with which drink feems to be converted
into urine, and particularly in man, who ufes a
large quantity of it.

The impoffibility of conceiving bow drink can
be fo fpeedily converted into blood, and this blood
into urine, has induced fome phyfiologifts to be-
lieve that there muft be fome more dire6t way than
circulation for transforming drink into urine ;
but this hypothecs is not fupported by our anato-
mical knowledge.

The phenomenon of the fecretion of urine ap-
pears extraordinary, merely becaufe it has not
been confidered under its real point of view.

The beverages which men ufe to excefs con-
tain, in general, alcohol or acids. Thefe fub-
ftances equally Simulate the (iomach and the

kidneys ;

RECAPITULATION, 419

kidneys ; and the limultaneous adlion of thefe
two organs maintains the continual excretion of
urine.

The ftomach, itimulated in a proper manner by
the prefence of liquors, digells thefe fluids; and
the aqueous part, taken up by the abforbing vef-
fels, becomes fpeedily mixed with the blood.

The kidneys, flimulated alfo by the aition of
liquors on the nerves of the ftomach, foon enter
into aftion, and the two large renal arteries do not
fail, in a fhort time, to convey to them blood over-
charged with aqueous parts. Thefe two circum-
llances produce the fecretion of urine, which is
effedled with activity, and the blood frees itfelf in
the kidneys from the water which it receives in
excefs from another quarter.

It is here feen that the drink, in this manner,
is not diret^ly transformed into blood, but that it
becomes mixed with it in the flate of water, and
that it is feparated from it by the continued and
heightened adlion of the kidneys.

Phylicians, therefore, have reafon for laying,
that thofe who drink abundantly ibajh their blood;
but it does not clearly appear what the blood can
gain by being wajhed in this rhanner.

Another very furpriling phenomenon exhibited
by blood, is the promptitude with which it acquires
certain odours, after a perfon has eaten or even
infpired certain fubflances.' Every one knows that

2 E 2- urine

420 VITAL FUNCTIONS.

urine acquires a very fetid fmell after eating af-
paragus, dnd that it finells of violets after fwallow-
ing turpentine, or only infpiring the eflence of it
for fome time. Thefe infiiances are commonly
quoted, as a proof of the rapidity with which the
aliments are transformed into blood ; but it is
probable that thefe fubftances aft only as particu-
lar itimulants of the kidneys, v.^hich produce a
change in the mode of fecretion of thefe organs.
This change is announced by a peculiar odour,
which for the moft part is not that of the fub-
ilance which produces it ; for the fmell of violets
lias no relation to that of turpentine,

no. From the different ads of life there refults
a phaenomenon, which forms one of the principal
cbara6lers of organized beings : namely, that of re-
taining a temperature nearly conftant, whatever be
the medium in which they live.

In man this temporature is about 4a degrees
of the centigrade thermometer (104° Fahren.) : it
neceflariiy refults from the a6iion of the different
lyftems of organs, and from the changes which
are continually effe*51ed in all parts of the body.
It may be obferved, that in the execution of thefe
different phasnomena, the fubftances which iffiie
from the body have more denfity than thofe which
-enter it; fo that the refult muft neceffarily be the
difengagement.of caloric; and it is to it, in all
" ' - probabilityj

RECAPITULATION. 421

probability, that the habitual elevation of the tem-
perature is owing.

Our aliments, indeed, confift of atmofpheric
air, and animal or vegetable fubftances, wif.h which
we, in general, unite a great quantity of water;
whereas the materials which efcape from our
bodies are, hardened excrements ; urine charged
with faline matters; un6luous fweat; thick excre-
tions, charged with albuminous, gelatinous, greafy,
faline, Sec, fubftances ^ and in the laft place car-
bonic acid gas. As all thefe produdts are evi-
dently more confiftent than the materials which
ferved to furnifh them, the tranfmutation of the
latter, which is continually effedled in every part,
of the organization, muft necefiarily be accom-
panied with a difengagement of caloric.

It is the air, in particular, digefted in the lungs,
which is the fubft:ance moft proper for furnifhing
caloric ; and it is indeed obferved, that the ca-
loricity of animals is greater, according as the
iyftem of refpiration is more extenlive, and as the
exercife of that fan<5lion takes place with more
aftivitv.

In an individual who ufes violent and continued
exercife, all the fecretions are accelerated, and the
difeno;ao:ement of heat becomes conftderable. Per-
fpiration, which is then proportioned to the quan-.
tity of caloric difengaged, carries off the excefs of
heat ; the temperature of the body is lowered, and
2 £ 3 remains

422 ' tlTAL FUNCTIOKS/

remains at the fame degree, by means of the cii-
taneous organ, which thus becomes the regulator
of caloricity.

Whqji a man is expofed to a very high atmo-
fpheric temperature, he feels himfelf oppreffedj
he experiences a ftrong tendency to repofe ; has
jio appetite, and is thus in a flate which difen-
gages very little caloric. At the fame time the
cutaneous organ, being ftrongly ftimulated by the
external heat, excretes an abundant fweat, the
evaporation of which, at the furface of the body,
carries off a great quantity of caloric.

In this ftate the want of alcoholic liquors, and
of different ftimulants, is ftrongly experienced.
It is almoft inconceivable what a degree of heat a-
robuft man is capable of, fuftaining for fome time.
But if the heat increafes or is maintained, he at
length falls into a flate of oppreffion, which may
become mortal.

On the other hand, when a perfon is expofed to
intenfe cold, he experiences an unealinefs which
excites him to motion ; circulation and refpirafion
are accelerated ; the air he infpires is more con-
denfed ; perfpiration is almoft annihilated; the
appetite is proportioned to the exercife, and all
the means which produce heat are put into adlion
to maintain the habitual temperature. The de-
gree of cold which a man refifts with good clothes,
exercife, and fpiritaous liquors^ is no lefs aftonifliing

than

RECAPITULATIOX. 423

tlian the degree of heat he is able to endure. But,
if he abandons himfelf to reft, the a61:ion of the
cold provokes fleepj and if he fleeps, in this fitua-
tion, he muft infallibly perifh.

III. The florid, fpiimous, arterial blood, which
is of a bright red colour, proceeds with rapidity to
every part of the organization, by an order of vef-
fels not very tortuous, the fides of which are ex-
ceedingly thick. Thefe vefTels are divided and
fubdivided in an indefinite manner, and lofe them-
felves in very minute ramufculi. As they divide,
their refpeiftive capacity is increafed, and the blood
circulates with lefs adivity in the rami than in the
trunks.

The blood acquires and retains a temperature
of 40 degrees of the centigrade thermometer*, by
the refult of the different fecretions, the materials
of which it furnifhes: it frees itfelf from the heat
which exceeds this temperature, by means of per-
fpiration ; and from its excefs of aqueous parts by
urinary fecretion.

The blood, in diilributing itfelf to all parts of
the organization, to fupply them with the materials

*The tranflator muft here obferve, that the author in different
parts of this work makes the heat of the blood to be 40 degrees
of the centigrade thermoaleter, or (04° of Fahrenheit, which is
7 degrees more than it is commonly-fuppofed to 'be) as mod
writers on phyfiology eftlmate this heat at 97 degrees of Fah-
renheit.

2 E 4 neceffary

4*24 VITAL FUNCTIONS.

neceffary foreffe^^ling the different changes which
are there continually tiiking place, undergoes a
very manifcft alteration. It then returns from ^he
different parts by two orders of veffels, the veins
and the lymphatics. The veins convey back the
greater part of the blood, that which has under-
gone the lead alteration, and which ftill retains a
brownifh red colour. The lymphatics collect the
refiduums of the different fecretions, and in gene-
ral all the fluids difFufed throughout the lar^e ca-
vities, or depofited in the cells of the different
tilllies.

The venous blood and the lymph proceed, flowly
in tortuous veflels, the thin lines of which are
furnifhed internally with valvular folds, which
prevent the return of the fluids. Thefe veffels
arife in imperceptible capillary ramufcuh, and
their fucceffive union forms rami, branches, and
trunks. Thefe vefTcls, in uniting, decreafe in re-
gard to their rcfpedtive capacity, and the fluids
they contain accelerate their progrefs as they ad-
vance from the rami into the branches. In the
laft place, the lymph receives the produ6l of di-
geftion, and mixes with the venous biood ; and
the latter, after pafling through feveral organs, re-
turns to the point fronri which it proceeded, in the
flate of arterial blood.

The lymphatics, in their pailage, traverfe the
j^umerous glands, in which the lymph experiences;

ji repeate4

RECAPITULATION. 425

a repeated affimilation, or fort of digct1:ion, which
gives to this tiuid chara6lers of vitality, and ren-
ders it proper for forming a part of the blood. It
is not until they have been thus properly affimi-
lated in the glandulous organs, that the fluids
abf^rbed by the lymphatics pafs into circulation.
By this dilpofition the blood can receive none of
thofe foreign fubflances which it is vulgarly be-
lieved can pafs into it with lb much facility, in'
order to infeft sts whole mafs.

The venous blood, which returns from the dif-
ferent parts of the abdomen, feems more particu-
larly to be charged with heterogenous fubftances.
The veins which bring it back unite into a large
trunk which proceeds into the liver. This blood,
in traverfing the hepatic organ, frees it felf from
the adipofe and albuminous fabftances which it
contains in excefs ; thefe fubftances, united to a
fmail quantity of foda, form in the bile a fapona-
ceous liquor, the excretion of which by the duo-
denum becomes one of the moft powerful agents
of digeftion.

The veins of all the parts unite into two large
trunks, which convey the blood to the right fide
of the heart, from which it pafles into the pul-
monary organ.

Jt is in pafling through this organ, in parti-
cular, during the a6l of refpiration, that the blood
experience? the moft remarkable changes, and

com-

Al2,6 VITAL FUNCTIONS.

completely refumes all its qualities of arterial
blood.

By the indefinite expanfion of the pulmonary
arteries, the blood is uniformly diffufed throughout
every part of the refpiratory organ, where it finds
itfelf, as we may fay, in immediate contacl with
atmofpheric air, introduced into the bronchial cells,
by paffing through the aerian canals, the fubdivi-
iions of which feem to equal thofe of the arteries.

During the adt of refpiration, the blood affumes
a beautiful fcarlet colour,, and becomes fpumous,
warmer and lighter than the venous blood ; the
atmofpheric air lofes a part of its oxygeuj perhaps
even a little azot, and becomes charged with nearly
the fame quantity of carbonic acid gas.

In the fun(5lion of the refpiratory organ, it is
probable that the part of atmofpheric air which is
wanting, has been digefted and abforbed in order
to fcrve for the general nutrition, and that the car-
bonic acid gas is the produd of the particular
fecretion which the blood efFe6ls in the lungs,
as the bile refults from that efFeded in the
liver.

In a word, the fides of the bronchial cavities
fecrete an abundant ferofity, which is continually
evaporating by expiration, and which becomes
one of the grand caufes of lofs.

1X2. The air expelled from the lungs becomes
I , ilill

* JIECAPITULATION. 427

fiill ufeful to the organization : this elaftic fluid,
driven oat with greater or lefs force, may give rife
to the formation of found.

The lungs, which continually receive and ex-
pel air, are proper for producing noife. Cries are
the firft language of pain in all the mammalia ;
and they afterwards become that iof joy and of
€?ery other fenfation.

Air put into a ftate of vibration, in its pailage
through the glottis, produces found by means of
the epiglottis, which ads the part of a pipe.

The fundamental found is furnifhed by the
larynx, the fhortening of which gives the odlaves,
and the con trad ion the harmonics.

The varied articulations of fpeech are produced
by the different parts of the mouth.

But thefe data are far from accounting for the
effeds of finging and of fpeech. It may be faid
tlTat the ae'rian paflages forni a very bad wind
inftrument, which man has found means to turn
to great advantage.

It mufl not be believed that fpeech, like an ear,
is the gift of nature: voice and fpeech are the refult
of overcoming a great difficulty ; and to this ob-
jecl the progrefs of civilization has contributed.

The children in civilized nations learn to fpeak
with facility, becaufe they inherit a fort of pecu-
liar difpolition for learning the language of their
fathers ; becaufe all thofe around them fpeak and

employ

, 4*28 VITAL FUNCTIONS.

employ every method proper for making them ac-
centuate ; and becaiife the firft years of life are
entirely devoted to that exercife.

But the ufe of fpeech is fo difficult to be ac-
quired, that it is fcarcely poffible to teach it to a
child who has palled the firft fifteen years of life
without hearing others fpeak.

Singing, perhaps, is attended with lefs diffi*
culty in the execution than fpeech ; and if all the
means employed to teach articulation vi^ere em-
ployed to teach modulation to the children of
good fingers, there can be no doubt that mufic
would become an art familiar to almoft every in-
dividual,

113. The reproduction of the human fpecies
feemstobe efi^e(51ed in a manner analogous to that
of all other organized beings. An egg, which
confifts of its germ and placenta, acquires in the
ovarium a certain increafe, beyond which it does
not proceed, until by the contaft of the fecun- .
dating fubftance it has received the impulfe of a
new life.

At this period it increafes, detaches itfelf from
the ovarium, traverfes the uterine tube, and fixes
itlelf in the uterus, where it remains nine months.
During this time the placenta, which is attached
to a part of the fides of the uterus, extrads from
it juices, which it ailimilatcs^ and which ferve for

its

KECAPITULATION. 4Sf

its increafe, as well as for that of the germ, by
means of the circulation eftablifhed between thefe
two parts.

When the foetus has acquired a certain growth,
and the placenta has attained to a certain degree
of maturity, both are expelled from the uterus by
the contraftile action of its fides. The child
then enjoys a new life, and ftill remains attached
to the mother, for fome time, by the need of
lactation.

The fyflem of generation feems to be indif-
ferent to and little connedled with the whole of
the individual organization : during the firft years
of life it has no influence ; it lofes its a6tion at
an advanced period, and may be fuppreiled with-
out great inconvenience : however, when its func-
tion is exercifed with great energy, it borrows
aid from all the other fyftems of organs, which
are entirely fubordinate to it ; and each concurs,
in its own manner, to favour its acS^ion.

The danger of employing this organ has been
too much exaggerated j like all the others, it is
lirengthened and maintained by moderate exer-
cife ; it is deftroyed by long inadlivity ; and yet
it may, with truth, be faid, that by excellive ufe
it is deftroyed much fooner than any other organ.
This function, highly important, fince it perpe-
tuates the fpecies, is one the ufe of which is ex-
cited by the mofl exquifite pleafure.

The

430 VITAL FUNCTIONS.

The exercife of this fundion ptocures a fenfa-
tion the more lively, as its duration is fhort : it
can therefore ferve only for employing a very
fmall portion of time. Among idle perfons, who
have acquired a habit and contra61ed a need of
this enjoyment, it is foon deftroyed by abufe ;
and the deiireof renewing a pleafure, which they
can no longer difpenfe with, leads to the mod ex-
traordinary expedients ; and moft inconceivable
extravagances, the refult of an exalted imagi-
nation, which varies all its refources, and tries
every mean proper for renewing a fenfation, be-
come neceflary, and for which the organ is more
or lefs completely unfit.

A great many lingular things have been faid
to explain thefe flights of the imagination, which
have been conlidered as peculiar tafles, natural
to fome individuals ; but they are merely the re-
fult of an ever-a6tive deiire to reproduce fenfa-
tions, which have become wants.

At the period of puberty, in perfons of a ftrong
conftiiution, who live in towns amidft eafe and
idlehefs, furrounded by objects which excite amo-
rous defires, the organ of reproduftion imperioufly
requires to be employed, and if completely prevent*
ed very ferious accidents may be theconfequencei

No liate, perhaps, is more painful, and no fitu-^
ation is worfe underftood, than that of a perfon.
who is continually employed- with a want which

he

RECAPITtJLATION. 4^\

he endeavours to reprefs. This condu6l main-
tains a fort of perpetual irritation in the genital
parts, which, in the end, generally produces very
fevere chronic affe6lions, and particularly among
the vt'omen.

The only rational and fure means of extiUf-
guifbing the action of this organ is, to give great
exercife to the reft, but efpecially to the mufcular
fyftem and the intellecfluai faculties, vi^hich always
occalions a falutary diveriion, arxi affords great
employment to the vital powers.

The moft important confideration, fuggetted
by the fyftem of reprodudlion, is that which re-
lates to the means it affbrds of tranfmitting to
children the general, and even the particular
difpofitions of the parents. This faculty leems
to belong to all organized beings ; and is obferved
in plants as well as in animals.

Experience has proved that there is no altera-
tion or affedtion, no phyfical difpolition or apti-^
tude for certain intellectual qualities, which are
not more or lefs fufceptible of being tranfmitted
by generation.

Reproduction, exhibits alfo one of the grand
means of the improvement as well as of the
deterioration of the human race. In this refpedt,
it muft always be recomembered that children,
caeteris paribus, have a greater refemb'ance to
their mother, in the eftcntial -^nd fundamental^

interior

432, VITAL FUNCTIONS.

interior parts, and to the father in regard to the
acceflbry or fuperficial parts.

1 14. Life and health are the eflential refult of a
proper adlion of the different funftions. Under
this point of view, it is proved by experience and
obfervation that the organs are ftrengthened by
moderate and habitual exercife ; that they are
weakened by repofe or forced exercife ; and that
the weaknefs or derangement of a fundlion has
always a greater or lefs influence on the whole of
the organization.

From our knowledge acquired in regard to the
organic ftru6iure it refults, that the bell com-
bination of the powers for rendering the organi-
zation mofl conducive to the happinefs of the
individual, and to the progrefs of civilization, is
when children receive an education founded on
a proper development of the phyfical and intel-
lectual faculties, and the ftudy of the exa(9: fci-
ences, and when they purfue the fameobjedl du-
ring the remainder of their lives, by diredling
their attention to one part of fcience or of art,
which they endeavour to improve. . ^

3 CONCLUSIO!?*

[ 433 ]

CONCLUSION.

115. Man enjoys a certain number of facul-
ties, the combined employment of which render
him fufceptible of indefinite improvement.

ill. He is provided with organs of loco-motion,
nutrition, and reprodu6lion.

2d. He is in relation with external objeifts by
means of the organs of the fenfes.

3d. He is excited to adt and to exercife his
different functions by the flimulas of pain; and
induced to fatisfy his Vv^ants by the defire of ob-
taining eafe.

4th. The fenfations he experiences may be re-
newed, without the prefence of the objedts which
at firft produced them, but merely by that of ob-
jects which were connected with the firfi:, and
which recall them.

5th. The organs are flrengthened by exercife,
and by repeated adlion acquire a great tendency
to habit.

6th. The peculiar difpofitions of the organiza-
tion are tranfmitted by generation.

In the exercife of his faculties, it is obferved,
that man is irrefiflibly excited to aB^ for the fake
of his own prefervation, and for the propagation

v®L. III. 2 ? of

434 VITAL FUNCTIONS.

of his fpecies ; that he continually experiences
direct fenfations, which recall others, and that he
is forced to combine dire6l fenfations with recalled
fenfat'wns, to deduce from them refults favourable
to his prefervation.

The faculty of aB'ing and comlnn'mg, for his
prefervation, may have been afterwards extended
to the fadlitious wants which were fncceffively
created.

This faculty agqoires great extent among men
who unite together in fociety. Daring the flow
progrefs of civilization, they are gradually feen to
increafe their means of exigence and of happinefs.
They fubflitute artificial for natural figns ; they
employ their cries as figns, and gradually tranf-
form them into language. By little and little
they acquire the habit of more continued atten-
tion.

The continual employment of fa6iitious figns
gives great extent to the faculty of having re-
called fenfatiuns. Through the neceffity of pro-
viding for urgent wants, and fatisfying ardent
dcfires, man foon forms combinations, more or lefs
extenfive, of the fenfations v^'hich he experiences.
The propenfity to rule is gradually changed into
a defire of. obtaining refped:. In a word, among
men in a fiate of civilization, who find them-
felves without employment, amidft all the means
of exiitence, this defire of refpedf, and the necef-

3 ^ fity

CONCLUSION. 435

iity of obtaining new fenfations, which always be-
comes flronger, makes all the faculties acquire an
extenlion, which increafes as the produ6l of their
combination.

Under thefe favourable circumftances, man be-
comes a being who has no refemblance to his ori-
ginal type : the point from which he fet out can
no longer be difcovered ; the path which he has
purfaed can fcarcely be traced out ; and his new
moral exiftence feems to be .^Uoo-pther divine.

TH^ END.

. K. WilXs, rriiiter, Chaiitciy-lane»

ERRATA.

Vol. I. page 373, line 10 from the bottom, for tracheal nrtert/t
read trachea.

Vol. II. page 147, line 5 from the bottom, after the word suc-
cessful, add hooping cough.

page 291, line 8 from the top, for synoche, read
synocha.

page 398, last line, for obsfipite, read obstipitas.

page 206, line 2 from the bottom, for mammill'*, read
breasts ; and,

page 207* line 4 from the top, for mammilla, read breast.

:.^r.