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[YSI0L0G1CAL RESEARCHES
LIFE   AND   DEATH,
BY XAVIER B1CHAT
ErawglatetJ from tfte ipreurtt.
             BY F. GOLD,

MEMBER OF THE ROYAL COLLEGE OF SURGEONS, LONDON

               WITH NOTES,

            BY F. MAGENDIE,
     Member of the Institute and of the Royal Academy of Medicine.
     THE NOTES TRANSLATED

BY GEORGE HAY WARD, M. D.
           BOSTON :
PUBLISHED BY RICHARDSON AND LORD.
J. H. A. FROST, PRINTER.
     X827. 
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              DISTRICT OF MASSACHUSETTS: to vit.

                                                  Dittricl  Clerks Office.

  BE IT REMEMBERED, That on the seventeenth day of December, A. D. 1827, in the
fifty-second year of the Independence of the United  States of America, RICHARDSON
&. LORD, of the said District, have deposited in this office the title of a book, the right
whereof they claim as proprietors, in the words following, to wit:
  11 Physiological Researches on Life and  Death, by Xavier Bichat; translated from the
French,  by  F. Gold, member of the Royal  College of Surgeons, London,  with  notes, by
F. Magendie, member of the Institute and of the Royal Academy of Medicine.  The notes
translated by George Hayward, M. D."
  In conformity to the Act of the Congress of the United States,  entitled, " An Act for
the  encouragement of Learning, by securing the copies of Maps, Charts and Books, to the
Authors and Proprietors of such Copies, during the times therein mentioned :" and also to
an Act entitled, " An Act supplementary to an Act, entitled, An  Act for the encouragement
of Learning, by securing the Copies of Maps, Charts  and Books, to the Authors and Pro-
prietors  of  such Copies during the times  therein mentioned; and extending the benefits
thereof to the Arts of .Designing, Engraving and Etching Historical and other Prints."
                   •                              JOHN  W. DAVIS,
                                          Clerk of the District of Massachusetts 
TRANSLATOR'S  PREFACE.
   THE  Translator of the Work which is here offered to the
Public, feels it quite unnecessary to expatiate upon the merits
of its Author, whose ideas and classifications in Physiology are
now very generally adopted.  He has supposed, however, that
the experiments which constitute the Second Part of the Work^
are not so familiar to Professional Men, as many of the conclu-
sions which have been deduced from them, and therefore has
presumed that  a greater publicity of these experiments will
by no  means be  unserviceable.  Dr. Kentish, in his account
of Baths, has  mentioned the circumstances which led to this
translation. 
 
ADVERTISEMENT BY THE FRENCH EDITOR.
   THE  work of  Bichat, which appears  to  the most
advantage, is the one that we now reprint; his observing
mind, his experimental genius and  his  lucid manner of
exhibiting facts  are  particularly observable in it.  This
work will have for a very long time a great influence on
physiologists and physicians.
   The Physiological  Researches on Life and Death have
had more than one class of admirers.  Exact minds, friends
of the progress of science have praised  it for the great
number of accurate observations  which it contains, the
ingenious management of the experiments and the correct-
ness of the  deductions; but they have regretted that the
author constantly placed life in opposition to physical laws,
as if living beings were not bodies before they were vege-
tables or animals.  They have seen with regret that he
offered illusory explanations of inexplicable phenomena.
   These  grounds of legitimate criticism  seem  to have
been  the reason of the  enthusiasm of  another class of
readers,  for whom whatever is vague appears to have a
great degree of attraction.  The readers, of whom I have
just  spoken, feeling but   little  interest in the new facts
which the Physiological Researches contain, have adopted
without examination its fallacious hypotheses, and attach-
ing to them an  importance which the author never did,
because they believed that they elucidated the mechanism 
VI
PREFACE.
 of the most obscure vital  operations, and  conducted to a
 true theory of medicine.  Should we lament this errour?
 Certainly not, as it  has  powerfully contributed  to  the
 brilliant success of Bichat's work, and  by means of some
 errours, much truth has been promulgated.
  As the works of  Bichat have now become classics and
 their reputation cannot  be increased, it is  time  to place
 young  students on their  guard against the  errours into
 which  the  imagination of the author led him, and which
 are the more to be feared, as Bichat in  order to convince,
 has employed  all  the fascinations of his animated style.
  The  memory of Bichat cannot  but gain by  it ;  the
 numerous truths which he has discovered will shine with
 a brighter light, when  freed from  the light shades that
 envelope them.
  Such is the object of the notes to  the present edition,
which  we have endeavoured to bring  up to the  present
state of knowledge. 
CONTENTS  OF  THE  WORK.
                       PART THE  FIRST.

                            CHAPTER   I.
                                                                       Page
Division of Life into Animal and Organic Life........11
                            CHAPTER   II.
General Differences of the two Lives, with regard to the outward form of their respec-
  tive Organs      ... *..........      15
                            CHAPTER  III.
General Differences of the two Lives, with regard to the mode of action of their
  respective Organs.............2d
                            CHAPTER  IV.
General Differences of the two Lives with respect to Duration of Action   .    .      40
                            CHAPTER   V.
General Differences of the two Lives with respect to Habit.....46
                            CHAPTER  VI.
General Differences of the two Lives with respect to Mental Affection        .      54
                           CHAPTER   VII.
General Differences of the two Lives with respect to Vital Power   ....    76
                           CHAPTER  VIII.
Of the Origin and Development of the  Animal Life......      132
                            CHAPTER  IX.
Of the Origin and Development of the Organic Life     .            ...    156
                            CHAPTER   X.
Of the Natural Termination of the Two Lives   .                     .    .      163 
VIII
CONTENTS.
                      PART THE  SECOND.

                              CHAPTER  I.
                                                                        frage
•eneral Considerations on Death..........    173
                              CHAPTER  II.
Of the Influence of the Death of the Heart over that of the Brain    .    .          176
                            CHAPTER  III.
Of the Influence of the Death of the Heart over that of the Lungs      .        .    19!
                            CHAPTER  IV.
Of the Influence of the Death of the Heart over that of all the Organs   .    .      194
                             Chapter  v.
Of the Influence of the Death of the Heart, as to the production of General Death    202
                            CHAPTER  VI.
Of the Influence of the Death of the Lungs over that of the Heart    .    .    .      210
                            CHAPTER  VII.
Of the Influence of the Death of the Lungs over that of the Brain      .    .   ,   237
                            CHAPTER   VIII.
Of the Influence of the Death of the Lungs over that of the Organs in general  .      252
                            CHAPTER  IX.
Of the^lnfluence of the Death of the Lungs over the General Death of the Body  .    276
                            CHAPTER  X.
Of the Influence of the Death of the Brain over that of the Lungs    .   .    .      297
                            CHAPTER  XI.
Of the Influence of the Death of the Brain over that of the Heart  ....    305
                            CHAPTER  XII.
Of the Influence of the Death of the Brain over that of all the Organs   .    .      318
                           CHAPTER   XIII.
Of the Influence of the Death of the Brain over that of the Body in General      .    332 
PHYSIOLOGICAL RESEARCHES
                 ON


LIFE  AND  DEATH.
PART THE FIRST.
CHAPTER I.
               GENERAL  DIVISION  OF  LIFE.

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

  * The form adopted by Bichat, in this work, has been much blamed
by some, and  extravagantly praised by  others.  The  blame and the
praise appear to me to be equally misplaced.   His object was to exhibit
the various phenomena of life ; the order in which this  was  to be done
was a matter of indifference.   If Bichat gave a preference to this form,
it was  because it was conformable to the nature of his mind ; and he
accomplished  his task in a  very happy  manner.   The division  that
he has adopted is not new, it may be found, with slight  modifications,
in writers of different periods, and even  in Aristotle.  Besides,'it is not
necessary in the sciences to attach a very great importance to classifica-
tion. All  these contrivances  have  been invented only  to aid  the
memory; and  the functions of living bodies are not so  numerous, as to
reader  it necessary in studying  them to lean upon systematic divisions.
               2 
10             PHYSIOLOGICAL RESEARCHES
 following  general  expression :—Life consists  in the sum
 of the functions, by which death is resisted.*
   In living bodies, such in fact is the mode of existence,
 that whatever surrounds them, tends to  their destruction.
 They are influenced ^incessantly by inorganic bodies; they
 exercise themselves, the one upon the  other, as  constant
 an action;  under such circumstances they could  not long
 subsist, were they not possessed in themselves of a perma-
 nent principle of reaction.   This principle is that of life;
 unknown in its nature, it  can be only appreciated by its

  *The word life has been employed by phj'siologists in two different
 senses.  With some, it means an imaginary being, the sole principle of
 all the functions which living bodies exhibit; with  others, it means
 only the assemblage of these functions.  It is  in this  last sense  that
 Bichat employs it.  This is what  he means to  say in  the  following
 sentence.  Life is the assemblage of the functions which resist death.
 He is wrong only in allowing the idea 0/ death to enter into it; for this
 idea necessarily supposes that of life.  There is then really a bad circle
 in this definition; but in putting aside what  is defective in the expres-
 sion, it may be seen that Bichat considers life  as a  result, not as a cause.
  Before and since the  time of Bichat, a great number of definitions of
 life has been given, which are either false or incomplete.   It should not
 be required of a definition, that it should give all the properties of the
 thing which it is designed to make known, this would be a description;
but we have a right to expect that it should assign to this thing certain
 characters which belong to it  alone, and thus distinguish it from every
thing else.
  Let us examine by this principle  the definition adopted in a modern
 work.  Life, it  is  said, is the  assemblage of the phenomena which
succeed each other, for  a limited time, in an organised being. This is
no doubt true of life ;  but, if it can also be applied to another  state,
it ceases to be a definition.  An animal has just died ; its organs  from
 that moment are subject to the  action of chemical affinities only;
 decomposition takes place, gases  are disengaged, fluids  flow out and
 new solid aggregates are formed.  After a time every molecular motion
 ceases ;  there remains only a certain number of binary, ternary combi-
 nations, &c.  Here then is an assemblage of phenomena taking place for
 a limited time in an organized body, and yet it is not life. 
ON LIFE AND DEATPI.
11
phenomena: an habitual alternation of action and reaction
between exterior bodies, and the living body, an alterna-
tion, of which the proportions vary according to the age
of the latter, is the most general of  these phenomena.
  There is a superabundance of life in the child:  In the
child, the reaction of the system is superior to the action,
which  is  made upon  it  from  without.   In  the  adult,
action and  reaction  are on  a balance ;  the turgescence of
life is  gone.  In the old man, the reaction of the inward
principle is lessened, the  action from without remaining
unaltered;  it is then that  life  languishes, and insensibly
advances towards  its natural term, which ensues when  all
proportion  ceases.
   The measure, then, of life in general, is the difference
which  exists between the  effort of exterior power, and
that of interior resistance.  The excess of the former is
an indication of its  weakness ; the  predominance of the
latter  an index of its force.


  I. Division of Life into Animal and Organic Life*

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

   *This distinction of the two lives  is bad, inasmuch as it lends to
separate phenomena  which have a very  intimate connexion, which
relate to a common object, and which are often produced by  means in
every respect similar.  Why should I rank among the organs of animal
life the muscular apparatus which carries the alimentary mass from the
mouth  into the oesophagus, and among those of the  other  life,  that
 which takes it from the cardiac orifice to the anus ?  Is not the action
 of the first apparatus  in  relation with nutrition as well as the  action of
 the last, and does not the muscular apparatus of the oesophagus act
 upon a body which is foreign to us, as well as that of the tongue and the
 pharynx ?  Do the motions of mastication  differ in  their object from 
12
PHYSIOLOGICAL RESEARCHES
other belonging  exclusively to the  latter.  In comparing
two individuals  from each of the  living kingdoms, the
one will  be seen existing only within itself, having with
what surrounds it the relations only of nutrition, attached
to the soil, in  which its  seed  has  been  implanted, born
there, growing there, and  perishing  there.   The  other
will be observed combining with this interior life, which
in the highest  degree it enjoys, an  exterior  life by which
it acquires a very  numerous series of relations with  all
surrounding bodies, a life, which  couples it to the  exis-
tence of  every other being, by which it is approximated,
or  removed  from  the objects  of its  desires  or its  fears,
and seems in appropriating every thing in nature to itself,
to  consider  every thing with regard to  its individual
existence only.*

those of which we have just spoken, and as to the means of execution,
does not the muscular action still perform the principal part ?
  We might in the same way  bring near each other  the motions by
means of which we seize our  food.  The  action  itself of the  senses,
which directs these motions,  is,  with  nutrition,  in a  relation more
remote, but not less necessary, and we see in the various  classes of
animals that their apparatus is  modified according to the different kinds
of nourishment.  If the distinction of the two  lives  be wanting in
justice, as to the object of the  functions it separates, we shall soon see
that the characters attached to the organs of  one  and the other do not
establish this division in a more striking  manner.
  * This division between  vegetables and animals is far from being so
striking as is here supposed ; these two classes of beings, so different
when we examine them in the  individuals  endowed with a very com-
plicated organization, approximate each other in  a remarkable  degree
when we descend to those species whose structure is most simple ;  it is
even remarkable that  the most constant character which  distinguishes
one from the other, is not found in the organs of animal life, but in those
of vegetable or organic life. The senses are one  after the other found
wanting; for in an  individual  in  whom we can  discover no nervous
system, there is no more reason to suppose  the existence  of the sense
of touch as a sensation, than to  suppose it in the sensitive  plant, the 
ON LIFE  AND DEATH.
13
   Thus it might  be  said, that  the vegetable is only the
sketch, or  rather the ground-work of  the animal; that
for the formation of the latter,  it has only  been  requisite
to clothe the former with an  apparatus of external organs,
by which it might be connected with external objects.
   From hence it follows, that the functions of the anirral
are of two very different classes.   By the one (which is
composed of an habitual  succession of assimilation  and
excretion)  it  lives  within   itself, transforms  into  its
proper substance the particles of other  bodies, and after-
wards  rejects  them  when  they  are  become heteroge-
neous to its nature.   By  the  other, it lives  externally,
is the  inhabitant of the  world, and" not as the vegetable
of  a spot only;  it feels,  it perceives,  it  reflects  on its
sensations, it  moves  according  to their  influence,  and
dionaea muscipula, and other similar plants; we see only action and
reaction.  The  motions of the arms of certain polypi no more suppose
volition than the motion of the root which follows a wet sponge, or that
of the branches which turn towards the light; the only very constant
character is the absence or presence of a digestive cavity.  To speak
of an animal as a vegetable clothed with an external apparatus of organs
of relation, is a  more  brilliant  than  profound  view  of  the  subject.
Buisson, who, in his division of the physiological phenomena, avoids this
inaccuracy, has himself fallen into  error ; he pretends  that  respiration
belongs exclusively to  animals;  and that  thus the division of Bichat
was not only unfounded but also  incomplete, since this function, which
is neither of vegetation nor of relation, could be  ranked under neither
life.  Buisson was not well  informed ; no doubt  the respiration  of
vegetables does not exhibit the  most apparent  phenomena of the
respiration of the  maunmalia, but every thing, which  essentially con-
stitutes the function, is found  in  the one as well as in  the other ;
absorption of the  atmospheric air, and  the  formation and exhalation  of
a new gas; the rest is only accidental and is not an appendage but  in
certain classes of animals.   In some reptiles, though we find a particular
organ for respiration, this organ is not indispensable ; it may be removed,
and the skin becomes the only respiratory organ ; and when finally,we
come to consider animals with  trachea, we see that the conformity
becomes more and more evident. 
14           PHYSIOLOGICAL RESEARCHES
 frequently is enabled to communicate by its voice its
 desires, and its fears, its pleasures, and its pains.
   The aggregate of the  functions of the first order,  I
 shall name the organic life, because all organized beings,
 whether  animal  or vegetable, enjoy  it  more or  less,
 because organic texture is the sole condition necessary to
 its existence.  The  sum of the functions  of  the second
 class, because it is exclusively the property of  the animal,
 I shall denominate the animal life.
   The series of the phenomena of these two lives, relate
 to the individual.  Generation, as  a function,,  regards the
 species, and thus has no place among them.   Its connec-
 tions with the greater  number of  the other functions are
 but very indirect ; it commences a long time  after them,
 it  is  extinct  a long  time before  them.   In  the greater
 number of animals the periods of its activity are separated
 by long  intervals of time, and during these, it is abso-
lutely null.   Even in man, with whom the remissions of
its impulses,  are much less  durable,  it has not a much
more  extensive connexion with the  rest of the  system.
Castration is  almost always marked by a general increase
of the  nutritive process;  the eunuch, enjoying indeed a
less degree  of vital energy,  but  the phenomena of his
 life being displayed with  a greater exuberance.  We
 shall here, then, lay aside the consideration  of the  laws
 which give us existence, and  occupy ourselves  alone on
 those which maintain us in existence.  Of the former we
 shall speak hereafter.

 II.  Subdivision of each of the two lives  into two
                 orders of functions.

   The animal and  the organic life,  are  each  of  them
 composed of two  orders of functions, which succeed  each
 other, and are concatenated in an inverse direction. 
ON LIFE AND DEATH.
15
  In the animal life, the first order is established  from
the exterior of the body, towards the brain ; the second
from  the  brain towards the organs  of locomotion and
the voice.  The impression of objects successively affects
the senses, the nerves  and the brain.   The first receive,
the second transmit, the third perceives the impression.
The impression, in  such way," received, transmitted, and
perceived, constitutes sensation.
  The animal, in the  first order of these functions, is
almost passive ; in the second, he becomes active.—This
second order is the result of the successive actions of the
brain  (where volition has been produced in consequence
of the previous sensation) of the nerves, which transmit
such volition, and of the locomotive  organs  and voice,
which are  the agents  of  volition.  External  bodies act
upon  the animal  by means  of the  first  order of these
functions, the animal reacts upon them by means of the
second.
  In  general there exists  between  the  two  orders  a
rigorous  proportion ; where the one is very marked, the
other is put forth  with energy.  In  the series of living
beings, the animal, which  feels. the  most,  moves also
the most.  The age of lively perception,  is that  also of
vivacity  of motion ;  in  sleep, where the  first order is
suspended, the second  ceases, or is exercised  only with
irregularity.   The  blind man, who  is  but half alive to
what  surrounds him, moves  also with a tardiness which
would very soon be lost, where his exterior communica-
tions  to be enlarged.
  A double  movement is also exercised in the organic
life; the one composes, the other decomposes the animal.
Such  is the  mode of existence  in the living body, that
what  it was at one time it ceases to  be at another.  Its
organization  remains  unaltered, but its  elements vary 
16           PHYSIOLOGICAL RESEARCHES
every moment.  The molecules of its nutrition  by turns
absorbed and rejected, from the animal  pass to the plant,
from the plant to inorganic matter, return to the animal,
and so proceed in an endless revolution.
  To such  revolution the organic life  is well  adapted.
One order  of its functions assimilates to the animal the
substances  which are destined to nourish  him ; another
order  deprives  him  of these substances, when,  after
having for some time made a part of it, they are become
heterogeneous to his organization.
  The first, which  is that of assimilation, results  from
the functions of digestion,  circulation,  respiration,  and
nutrition.  Every  particle, which is foreign to the body
before  it becomes  an element of it, is subject to the
influence of these four functions.
  When it has afterwards concurred for some time to the
formation of the organs, the absorbents  seize on it, and
throw  it out into  the  circulatory torrent,  where  it is
carried  on  anew,   and  from  whence it issues by the
pulmonary or cutaneous exhalations, or by the  different
secretions by which the fluids are ejected from the body.
  The second order, then, of the  functions of the organic
life, or that of decomposition, is formed of those of absorp-
tion, circulation, exhalation, and secretion.
  The sanguiferous system, in consequence, is  a middle
system, the centre of the organic life, as the brain is the
centre of the animal  life.  In this system  the  particles,
which  are about to be assimilated, are circulated and inter-
mixed with those, which having been already assimilated,
are destined to be   rejected;  so that the blood itself is a
fluid composed of two parts ;  the one, the pabulum of all
the parts of the body, and  derived  from the  aliment;
the other, excrementitious, composed of the wrecks  and
residue of the organs, and  the  source  of the   exterior 
ON LIFE  AND DEATH.
17
secretions  and  exhalations.—Nevertheless these  latter
functions serve also, at times, the purpose of transmitting
without the  body,  the  products  of  digestion,  although
such  products  may  not have  concurred to  the  nourish-
ments of the parts.   This circumstance may be  observed
when urine and sweat are secreted after copious drinking.
The skin and the kidneys being at such times  the excret-
ing organs, not of the mattter of the nutritive, but of that
of the  digestive process ; the same  also  may be  said of
the milk of animals, for  this is a fluid which certainly has
never been assimilated.*
   There does  not exist  between the  two  orders of the
functions of  the  organic life the  same  relation, which
takes   place  between   those  of the   animal  life.    The
weakness of the first ■ by  no  means  renders absolutely
necessary  a  decrease  of action  in the second.  Hence
proceed  marasmus  and  leanness, states, in  which  the

  * Bichat seems here to adopt the generally received opinion that it is
the chyle which furnishes to the mammary gland the materials of which
the milk is composed.  We know not whence this  opinion  arises, if it
be not from  the gross resemblance which the chyle  and  milk  often
exhibit.   This resemblance, if it were very great, would be a poor
reason for admitting, vvithout  anatomical proof, so singular a fact; but
it is very far  from being perfect.   The chyle in fact does  not exhibit
the milky appearance and  the white opake colour, only when the
animal from whom it is taken, has fed upon substances containing fat ;
in  all other cases, it is almost transparent; its  odour and taste, under
all circumstances, differ entirely from those of milk; if these two fluids
are left to themselves, the milk remains a long time without coagulating,
but the chyle almost immediately coagulates, and then separates into
three parts.  The solid portion soon exhibits cells, and an  appearance
of organization ; nothing similar is seen in the cogulum of milk; the
serum of the milk  remains  colourless when  exposed to  the simple
contact of the air, that of the chyle assumes  a ropy tint, often very
vivid.   Finally, if we examine the chemical  composition of these two
fluids, we shall find  in them differences still more  striking. (See for
farther details, my Elements of Physiology, Vol. 2d.)
               3 
18          PHYSIOLOGICAL RESEARCHES
assimilating process ceases in part, the process of excre-
tion remaining unaltered.
  Let us  leave, then, to other  sciences,  all  artificial
method, but follow the concatenation of the phenomena
of life, for connecting the ideas which we form  of them,
and we shall perceive, that the greater part of the present
physiological divisions, afford us but uncertain  bases for
the support of any thing like a solid edifice of science.
  These   divisions  I  shall  not  recapitulate ;   the  best
method  of demonstrating their inutility will  be, if  I
mistake not, to prove the solidity of the  division, which
I have adopted.   We shall now examine the great differ-
ences, which separate the animal existing without,  from
the animal existing within, and wearing itself away in a
continual  vicissitude of assimilation  and excretion.
                   CHAPTER  II.

GENERAL DIFFERENCES OF THE TWO LIVES WITH REGARD
     TO THE OUTWARD FORM OF THEIR RESPECTIVE
                       ORGANS.
      ■
  The organs of the animal life are symmetrica], those
of the organic  life irregular in their conformation; in
this  circumstance consists  the most essential  of  their
differences.   Such character, however, to  some  animals,
and among the fish, to the sole and turbot especially, is
not applicable; but in  man it is exactly traced, as well as
in all the genera which are  nearest to him in perfection.
In them alone am I about to examine it. 
ON LIFE AND  DEATH.                19
1. Symmetry of the external forms of the animal life.*

  Two  globes in  every  respect the  same,  receive the
impressions of light.   Sounds and odours, have also their
double analogous organ.   A single membrane is affected
to savours, but the  median line  is  manifest upon it, and
the two segments, which  are indicated  by it, are exactly
similar.  This line  indeed is not every where to be seen
in the skin, but it is every where implied.   Nature, as it
were, has forgotten  to describe it, but from space to space
she has laid down  a number of points, which  mark its
passage.  The cleft at the extremity of the  nose, of the
chin, and the middle of the lips, the umbilicus, the seam
of the perineum, the projection of the spinous apophyses
of the  back, and  the hollow  at  the posterior part of the
neck are the principal  points at which it is shewn.
  The Nerves, which  transmit the  impressions received
by  the senses,  are evidently  assembled in symmetrical
pairs.
  * It is rather to the external  forms that symmetry appears to have
been primitively attached, and it is in some measure accidentally and
because the nature of their functions requires in  general  that they
should be placed on the exterior, that the organs of relation are found
modified in virtue of this law.  In the example cited, of fishes without
a bladder, the eyes, to lose nothing of their utility,  must be differently
placed, and on the face, which alone i> in relation with the .light; yet
even in this case, the symmetry of external  forms has been displaced
rather than destroyed, and  at the first examination  it seems complete.
When the organs of relation are found placed on the interior, they
frequently exhibit some irregularity, and to take an example of a known
animal, the organ of voice, in the male duck, is a very remarkable one;
in man even, the wind-pipe is not symmetrical, after it arrives at the first
division of the bronchia.  On  the contrary, among the organs  of the
other  life, those  which are prominent on the exterior, constantly
present the symmetrical character, as the thyroid gland," the mammary
glands, &c. 
 20          PHYSIOLOGICAL RESEARCHES

   The  brain,  the  organ (on  which the impressions  of
 objects  are received) is remarkable also for the regularity
 of its form.  Its double parts are exactly alike, and even
 those which are single, are all  of  them  symmetrically
 divided by the median line.
   The  Nerves  again, which transmit to the agents  of
 loco-motion and of the voice, the volitions of the brain,
 the locomotive organs also, which are  formed in a great
 degree of the muscular system, of the  bony system, and
 its  dependencies, these together with the larynx  and its
 accessaries,  composing  the  double  agents  of volition,
 have all of them a  regularity, a symmetry, which are
invariable.
  Such  even is the truth of the character which I am now
 describing, that the muscles  and the nerves immediately
cease to be regular, as soon as they cease to  appertain  to
the animal life.  The heart, and the  muscular fibres  of
the intestines are proofs  of this  assertion in the muscles;
in the nerves, the great sympathetic, is an evidence of its
truth.
  We  may conclude then from  simple inspection, that
Symmetry is the essential character of the organs of the
animal  life of  man.

II.  Irregularity of the exterior forms of the organic
                         life.

  If at  present we pass to the viscera'of the  organic life,
we shall perceive a character directly the contrary of the
former.   The   stomach,  the  intestines, the  spleen, the
liver, &c.  are all of them irregularly disposed.
  In the system of the circulation, the heart and the large
vessels,  such, as the upper divisions of the aorta, the vena
azygos,  the vena portse, and the  arteria innominata have 
ON LIFE AND DEATH.
21
 no one trace of symmetry.  In the vessels of the extremi-
 ties continual varieties are also  observed, and when they
 occur, it is particularly  remarkable  that their  existence
 on one side in no way affects the other side of the body.
   The apparatus of respiration appears indeed at first to be
 exactly regular ; nevertheless, the  bronchi are dissimilar
 in length, diameter, and  direction ; three lobes compose
 one of the lungs, two  the other :  between  these organs
 also, there is a manifest  difference of volume ; the  two
 divisions  of the pulmonary artery resemble  each other
 neither in  their  course, nor in  their diameter ;  and  the
 mediastinum is sensibly  directed to the left.  We shall
 thi^> perceive that symmetry is here apparent only, and
 that the common law  has  no exception.
   The organs  of exhalation and absorption, the serous
 membranes, the thoracic  duct, the  great  right  lymphatic
 vessel, and the secondary  absorbents  of all the parts have
 a distribution universally unequal and irregular.
   In the  glandular system also we see the  crypts, or
 mucous follicles  disseminated in a  disorderly  manner in
 every  part; the  pancreas, the liver,  the salivary glands
 themselves, though at  first sight more  symmetrical,  are
 not exactly submitted to  the median line ; added to this,
 the kidneys differ from each other in their situation, in
 the length and  size of their artery and vein, and  in their
 frequent varieties more especially.*

  * If we deny symmetry to the kidneys, because they are not uniformly
composed of the same number of lobes  in  children, we  must deny it
also to  the brain,  the two  lobes of which never exhibit the same
arrangement in their circumvolutions ;  if we deny it  to the  salivary
glands,  because one is larger than the other, we must deny it to the
extremities, because the right is usually more  developed than the  left.
If these examples are not enough, a host of others might be cited ; such
as, the atrabiliary capsules, the bladder, the  different organs of genera-.
tion and lactation, and the  very regular arrangement of the mucous 
22           PHYSIOLOGICAL RESEARCHES
   From considerations so numerous we are led to a result
 exactly  the  reverse of the preceding  one; namely, that
 the  especial  attribute of the organs of the interior life is
 irregularity of exterior form,

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

   It follows from the  preceding description, that the
 animal  life is  as it  were double ; that  its phenomena
 performed as they are at the same  time on the two  sides
 of the body, compose a system in each  of them inde-
 pendent of the  opposite system;  that there is a  life- to
 the, right, a life to  the left;  that the one may exist, the
 other ceasing  to do so,  and  that  they  are  doubtless
 intended reciprocally to supply the place of each other.
  The latter  circumstance we may frequently observe in
 those morbid affections so common,  where  the  animal
 sensibility and  mobility are  enfeebled, or annihilated  on
 one  side of the body, and capable of no  affection  what-
 ever ; where the man on one  side is little  more than the
 vegetable, while  on the other he preserves his claim to
 the animal character.   Undoubtedly those partial palsies
 in which the median  line, is the limit where the faculties
 of sensation  and motion  finish,  and  the  origin from
whence they  begin  can never  be remarked so invariably
in animals, which,  like the   oyster, have  an irregular
 exterior.
  On the contrary the organic life is a single  system, in
 which every  thing is  connected and concatenated ;  where

follicles in certain parts situated upon the median line, &c. As to the
anomalies that are observed in the distribution of the blood-vessels, they
are also observed very frequently, though in a less evident manner, in
 the distribution of the nervous branches. 
ON LIFE AND DEATH.
23
the functions on one side cannot be interrupted, and those
on the other subsist.  A diseased liver influences the state
of the stomach ;  if the colon on one side cease to act, that
upon the other side cannot continue in action :  the same
attack, which arrests the circulation  in the right side of
the heart, will annihilate it  also in the left side of the
heart.   Hence it follows, the internal organs on one side
being supposed to suspend  their functions, that  those  op
the other must remain inactive, and death ensue.
  This assertion,  however, is a  general one ;  it is  only
applicable to  the  sum of the  organic  life, and  not to  its
isolated phenomena.  Some of them in fact are double,
and their place may be  supplied—the kidneys  and lungs
are of  this description.
  I shall not enquire into the  cause of this remarkable
difference,  which  in  man,  and those  animals which
approach him the nearest, distinguishes the organs of the
two lives.  I shall only observe, that it enters essentially
into the nature of their phenomena, and that the perfec-
tion  of the  animal functions is  so  connected  with the
general symmetry observed in  their respective organs,
that  every  thing which troubles  such symmetry, will
more or less  impair the functions.
  It is  from  thence,  no doubt,  that proceeds  this other
difference of the  two  lives, namely, that nature  very
rarely  varies  the usual conformation of the organs of the
animal life.   Grimaud has  made  this  observation, but has
not shewn the principle on which it depends.
  It is  a fact, which cannot have escaped any one the
least accustomed to dissection, that the  spleen, the liver,
the stomach, the kidneys, the salivary glands, and others
of the internal life, are  frequently various in form, size,
position, and direction.   Such in the vascular system are
these  varieties,  that  scarcely will  any  two subjects  be 
24
PHYSIOLOGICAL RESEARCHES
found exactly alike under the scalpel of the anatomist:
the organs of absorption, the  lymphatic  glands in par-
ticular, are rarely the same either in number or volume,
neither  do the  mucous  glands  in any way affect a fixed
and analogous situation.
  And  not only is each  particular system  subject  to
frequent aberrations,  but the  whole  of  the  organs  of
the  internal  life are  sometimes  found  in  the inverse
of the natural order.  Of this I have  lately  seen  an
instance.
  Let us now consider  the organs of the animal life, the
senses, the brain, the voluntary muscles, and  the larynx :
here every thing is  exact, precise, and rigourously deter-
mined.  In these there  is scarcely ever seen  a variety  of
conformation ;  if there  do exist  any, the  functions are
troubled, disturbed, or destroyed: they remain unaltered
in the organic life, whatever may  be the disposition  of
the parts.
  The difference with respect to action, in the organs  of
the two lives, depends,  undoubtedly, upon the symmetry
of the one, whose functions the least change of conforma-
tion  would  have disturbed,  and  on the  irregularity  of
the other,  with which these  different  changes  very well
agree.
  The functions of  every organ of the animal life are
immediately connected with the resemblance of the organ
to its fellow on the  opposite side if double,  or if single  to
its similarity of  conformation in its two  halves:  from
hence the influence  of organic changes upon the derange-
ment of the functions may be well conceived.
  But this assertion will become more sensible, when I
shall have pointed out the relations  which exist between
the symmetry and the irregularity of the organs, and the
harmony and the discordance of their functions. 
ON LIFE AND DEATH.
25
                   CHAPTER  III.

GENERAL DIFFERENCE OF TH TWO  LIVES WITH REGARD
          TO THE MODE OF ACTION OF THEIR
                 RESPECTIVE ORGANS.

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

     I.  Of harmony of action in the animal life.

   We have already observed, that  the  animal life arises
from the successive actions of the senses, the nerves, the
brain, the  locomotive organs, and  the  voice.  We shall
now consider what harmony of action is, in each of these
great divisions.
   The precision of our sensations appears to be the more
complete in proportion as there  exists a resemblance
between the two impressions, of which  they  are each of
them the  assemblage.   We see  inaccurately when one
of the eyes is better formed, and  stronger than the other;
when it conveys to the  brain a clearer  image than its
fellow does.   It is to avoid this  confusion that we shut
one eye, while the action of the other is increased by the
              4 
26
PHYSIOLOGICAL RESEARCHES
 application of a  lens, for at such time there can be no
 harmony of action in the two  organs;  accordingly, we
 make use of one of them only in order to avoid the dis-
 cordance of the impression.—What a lens applied to one
 eye only produces artificially, is exemplified in a natural
 way by squinting.—We  squint,  says  Buffon,  because
 we turn the  weaker eye from  the object on which the
 stronger is fixed; for in so doing we avoid the confusion,
 which would arise from the  perception of two dissimilar
 images.
  We  know  that many other causes may contribute  to
 the production of this  effect, but we cannot doubt the
 reality of the  reason assigned.   We know also, that  in
 some animals each eye may act without the assistance of
 the other, and that two different objects  may be trans-
 mitted at the same time by the two eyes of certain other
 animals; but this circumstance, when the action of both
the organs  is united  upon a single  object, should by no
means prevent a similarity in the two impressions.  A
single sensation  is the consequence of the combination ;
but in  what way can such  sensation  be  formed  with
accuracy, if the same body at the same  time be pictured
both in  strong and weak colours on the one and the other
of the retinae ?
  What we have said of  the eye may be equally well
applied  to the ear.  If, of the two sensations which form
a sound, the one  be received by a strong and well formed
organ, the other by a weak one, the impressions will be
unequal; the brain also, because it is differenlly affected
by each, will be the seat of an imperfect perception.
Such conformation constitutes what is called an incorrect
or false  ear.   For what reason does it  happen that one
man  is  unpleasantly affected by a dissonance,  while
another does not even perceive it?   The  reason is  this. 
ON LIFE AND DEATH.
27
that in the one, the two perceptions of the same sound
are identical;  in  the other, dissimilar.*  For the same
reason a man with a correct ear will combine his dancing
with  the cadence of the  measure  given him; another
without this similarity of organ  will  be as  constantly at
variance in his motions with the  orchestra.
   Buffon has  confined  his  observations on harmony of
action,  to the organs  of vision  and  hearing ;  we  shall
push  our examination of it  farther.
   In  the sense of smelling,  as well as  in the other senses,
we must admit of two impressions;  the one  primitive,
and belonging to the organ, the other 'consecutive, and
affecting the sensorium : now the  latter may vary, the
former remaining unaltered.  Many odours  are disagreea-
ble to some, but pleasant to others ; and this,  not because
there is any difference  in  the affection of the pituitary
membrane, but because in different individuals, the mind
may  attach a very different sentiment to the same impres-
sion.—Hence a variety  of  results  does not in  this case
suppose a difference of principle.
   But  sometimes the impression which is made upon the
pituitary membrane does really differ from that which it
ou°-ht to be, for producing  perfect  sensation.   Two dogs
 pursue  the  same game ; the one  never loses  scent, but
 makes the same turnings and windings with  the  animal

   * This supposition, though no  doubt ingenious, is not true.  If the
 want  of accuracy of hearing arose in fact from the  inequality of the
 power of the two organs, this defect might be  remedied  by using but
 one ear; but experience gives a different result.  We shall not discuss,
 in relation to the same principle of inequality of the organs, the explana-
 tion of strabismus; but at least,  for every thing that  relates to the just
 appreciation of colours, this principle is no more applicable than to the
 just appreciation of sounds.  I know a man who has never been able
 to distinguish the blue of the sky from the  green of the sea, and he
 succeeds no better by closing one eye. 
PHYSIOLOGICAL RESEARCHES
before him ; the other follows his  game  also, but  often
stops and hesitates, endeavors to recover  the scent,  pro-
ceeds  and stops  again.   The  first of these  receives a
lively  impression of the scented emanation ;  the organs
of the second are only confusedly affected.  Now it  may
be asked whether this confusion does not  arise from the
unequal action  of the two nostrils,  from the  superior
organization of the one, and from the imperfection of the
other ?—the following observations appear to  decide the
question.
  In the coryza, which affects but one of  the  nostrils, if
the two be suffered to remain open, the sense of  smelling
is confused ; but let the diseased  nostril be shut, and the
smell shall immediately become distinct.   A  polypus in
one of the nostrils debilitates the action of the pituitary
membrane on the affected  side, the other remaining in its
healthy state : hence, as in the  preceding case,  ensues a
want of harmony in the two organs, and the same confu-
sion in the  perception of  odours.   The greater number
of the affections of a single nostril have  similar effects,
which  may be all of  them corrected by the same means,
And wherefore? because in rendering one  of the pituitary
membranes  inactive, we  put  a  stop  to the discordance
Which  is  occasioned by the deficiency of action in the
other.   From the above facts (since any accidental cause,
which  destroys the harmony of action in these organs,
is capable  of rendering the perception of  odours  inexact)
we may conclude, that when the perception is naturally
inaccurate, there is a natural dissimilarity in the forma-
tion  of the organs, and therefore a difference of power in
them.
  The same reasoning  may be. applied to the  sense of
taste.  It  is often the case that one side of the tongue is
affected by palsy or spasm, the median line dividing the 
ON LIFE  AND DEATH.
29
insensible half from the other, which  continues to pre-
serve its sensibility.   But such affection may take place
in a variety of degrees, and one side of the tongue retain
a power of perceiving savours though  in a less  perfec-
tion  than the other side.  In such case it is natural to
suppose  that the  taste must be confused;  because a clear
perception cannot be  the  consequence of two unequal
sensations.
  The perfection of the touch as well as that of the other
senses,  is essentially connected with uniformity of action
in the two symmetrical halves of the body, and particu-
larly in the hands.  Let us suppose, for instance, a man
born blind, to have one hand well  organized,  the other
defective in the power of  moving the thumb and  fingers,
and  forming only a  stiff and immovable surface ; such
person  would find it a very  difficult thing to  acquire a
just notion of the size and figure of bodies, because the
same sensation would not  arise from the successive appli-
cation  of each hand  to  the  same  substance.   Let both
of his  hands, for example, be supposed to touch a small
sphere;  the one  by the extremities of the fingers will
embrace it in all  its  diameters, and convey to him the
idea of roundness ; the other, which will be in  "contact
with it only  in a few  points, will  produce a very different
sensation.  Embarrassed between these two bases of his
judgment, he wrill scarcely be able to  decide,  nay, it is
even possible that he  may form a double judgment from
the double sensation which is presented  him : his ideas
would  be  more  correct were  he to use only the perfect
hand, in the same manner as the  person who squints,
makes use of the perfect eye only.  Our hands then assist
each  other reciprocally;  the one  confirms the  notions
which  are given us by  the other;  hence the  necessary
uniformity of their conformation. 
30            PHYSIOLOGICAL RESEARCHES

  The hands  are  not the only instruments of the sense
of touch.  The axilla, the groin, the  concavity of the
foot and  many other parts,  may all of them from  their
application to  bodies, afford  us so many  bases for our
judgments with  regard to external  form.   Now, if one
half of the body were differently arranged from the other
half, the same  uncertainty in perception would  infallibly
be  the  result.  From all that has  been said, we  may
conclude, that in the external organs of sense, a harmony
of action in the two symmetrical parts, or the two similar
halves of the  organ,  is a condition  essential to the per-
fection of sensation.
  The  external  senses are the natural excitants of the
brain.   The functions of the  brain succeed to theirs, and
this organ would but languish, were it not to find in  them
the  principle  of its  activity.  From sensation follow
perception, memory  and imagination ; from these the
judgment.  Now it is easy to prove, that these  different
functions, commonly known  by the  name of the internal
senses,* are governed in their  actions by the same  laws,
which influence  the external senses ; and that like them,
they approach the nearer to  perfection in proportion  to
the degree of harmony existing in the symmetrical parts,
in which they have their seat.
  Let  us suppose for instance one hemisphere of the
brain to be better organised,  and therefore  susceptible of
livelier affections than its fellow ; in  such  case the per-
ception of the individual would be confused, for the  brain
is to the  soul  what the senses are to the brain; it transmits
  * We cannot,  without confounding all the ideas we have formed of
the senses, give this name to the  memory, imagination and judgment ;
at the most we might give  the  name of internal senses to certain sensa-
tions which inform us of the particular state of some internal organ, in
 the same way as the external senses make us acquainted with  the
 properties  and state of external bodies. 
ON LIFE AND DEATH.
31
to the soul the impressions conveyed to it by the senses,
as the senses convey to the brain the impressions  made
upon them by external  objects.   But, if the defect of
harmony in the external senses confuse the perception of
the brain, why may not the soul perceive but confusedly,
when the two hemispheres of the brain are unequal in
power,  and incapable  of blending into one  the double
impression, which is made upon them ?
  The   memory is  the faculty of  re-producing former
sensations, the imagination  that of  creating new  ones,
now in the act of remembering or imagining, each hemis-
phere of the brain  appears  to  re-produce,  or to  create
a sensation of its  own.   If both  do not act alike, the
perception of the mind, which ought to be  the  result of
the two sensations  united, will be inexact and irregular.
But, it is evident, that there  will be a disparity in the
two sensations, if there be a  disparity in the two halves
of the  brain, in which they  have arisen, and  since the
general  foundations of the judgment are made up'of the
faculties of perception, memory, and  imagination, if these
be confused,  the judgment itself must  be confused also.
  We have now supposed an inequality  of action  in the
hemispheres of the brain, and inferred, that the functions
would in this supposition be imperfect; but what  as yet
is only  supposition,  in  a variety of  instances can  be
proved  to be a fact ;  for nothing is more common than to
find in  consequence of compression on either hemisphere
by blood, pus, or exostosis, a variety of alterations  in the
intellectual functions.
  Even when all appearances of actual compression have
vanished, if  in consequence of that   which has  been
experienced,  a part of the brain  remain  enfeebled, the
same alterations of  mental power will be  found  to  be
prolonged.  If both  hemispheres of  the  brain, however, 
32
PHYSIOLOGICAL RESEARCHES
be affected equally, the judgment though weaker, will be
more exact.*   Perhaps it is  thus, that we should explain
those observations so frequently repeated, of an accidental
stroke upon one  side  of the head  having  restored  the
intellectual  functions, which had long remained  dormant
in consequence of a blow received upon the other side.
  I  now conceive  myself  to  have  proved, that with
inequality of action in the  hemispheres, there  must be
confusion of  intellect.  I have also  pointed out some
states of  disease,  in  which  such confusion  is evidently
the effect of inequality  of action so occasioned ; here we
see the effect and its cause; but may we not from analogy,
infer a similar cause where we  see a like effect? when
the judgment is  habitually  incorrect, and  all the ideas
wanting  in precision, may we not be  induced to believe,
that there does exist a defect of harmony in the  action of
the two hemispheres of the brain ?  We see inaccurately
if nature  have not given to both eyes an equal power ;
we  perceive and judge inaccurately  in like manner, if the
two sides of the brain are naturally dissimilar.  The most
correct mind, and the soundest judgment, pre-suppose in
the  hemispheres a perfect harmony of action  ; and what
a multiplicity of shades do we not  behold in  the opera-
tions of the understanding?  it is probable that they all of
them correspond to so many varieties in the proportions
of power in the hemispheres.  Could we squint with the
brain as  we do with the eyes—that is to say, could we
  * We cannot conceive how the judgment can be weak or strong, if
we do not  understand  by it that it is habitually accurate  or inaccurate.
His judgment is sound who usually perceives the true relations between
things ; and this is independent of  the number and variety of the ideas
upon which he has to pronounce.  The man to whose  mind there is
presented  but a small number of relations, has but little imagination ;
but if these relations be true, we cannot say that his judgment is
weak. 
ON LIFE AND  DEATH.
33
receive impressions on  one  hemisphere only, and form
from thence our determinations, we might then command
at will, a  precision in  our  intellectual  operations ;  but
such a power does not exist.
   To the functions of  the brain succeed those of locomo-
tion  and  the voice.   The  first of these  would appear
almost to  form an exception to  the general  law.   In
considering the two vertical halves of the body, we shall
perceive  that  the one  is constantly more powerful than
the other with respect to the strength and  number of its
movements.   The right half is that, which from custom,
is most made  use of.
   To  comprehend the reason  of this difference;  we
must make a  differerence  between  strength  and agility;
strength depends upon the perfection of the organization,
on the  energy of the  nutritive process, on the plenitude
of life  in the  muscular fibre; agility, on the contrary, is
the result of habit and frequent exercise.*

  * Bichat, in order to retain for the organs of organic life the character
of irregularity in the forms  which he had assigned to them, has been
compelled  to avail  himself of the inequality  of the size of the  con-
generous organs.  He soon repented  having  established  an  uniform
principle;  and in this  case for example, he is  near being condemned
by the very sentence  which  he has himself pronounced.  The loco-
motive system, in fact, the symmetry of which no  person before him
thought of  denying, is destitute of it according to the principle he has
established, since it presents in its two halves an inequality of size and
action.  In order to avoid this consequence, Bichat has maintained that
the inequality of size arose from the inequality of action, and that this
was the result, not of an original disposition, but of our social habits
only.  To prove this assertion, he has been compelled to heap sophism
on sophism ; he cannot in this case be suspected of a wish to deceive ;
he was convinced of the truth of the principle, and we know that to
prove what is believed to  be true, the weakest reasons always seem
to be sufficient.  But these very errors should be turned to our advan-
tage,  by showing us how  dangerous is the tendency  of generalizing
               5 
34
PHYSIOLOGICAL REESARCHES
   At  present  we  shall observe, that  this  disparity  ot
action in the  locomotive organs, does not consist in the
difference of  their  actual strength, but  in  that  of the
agility, with  which these motions are  executed.—All  is
equal  in the  size, in  the number of fibres,  and  nerves
both of  the one and the other of the superior, or inferior
extremities;  the difference of their vascular  systems  is
scarcely  any  thing.    From  hence  it follows  that the
discordance does not  exist in nature,  but that it is the
effect  of our social  habits,  which   by multiplying our
movements on  one  side  of the body, increase  their
address  without much  adding to  their power.   Such  in
fact are  the  wants of  society, as  to call forth a  certain
number of general movements, which must be performed
by all in the same direction, in order to be  understood.
It is  generally agreed, that  this  direction shall be from

upon every thing, since it  was capable of misleading so judicious a
mind.
   Without stopping to refute in detail all  the reasons which he has
advanced to support his opinion, we cannot help saying something of
them; and in the first place, the difference of size uniformly exists ;  it
is evident that it does not arise from grest exercise, since it is found in
the infant at birth, and the  nourishing artery of the right arm is larger
than that of the left.  If the right arm be not really stronger than the
other, why should we always use it in preference ?  If  we employ it in
writing, should we say with Bichat, that it is only  because it is better
situated to move from left to right, in the order in which the characters
of our  writing succeed each other ; might it not  be said, with more
reason, that our letters go from left to right, because it is the direction
in which  the right  hand most easily traces them ?  All this besides
relates merely  to the  form of our characters, since  all the oriental
languages are written from right to left; yet it is always done with the
right hand.  Is  it still said that the necessity of union in battle has led
to the employment of the  right arm to hold the  weapons,  as if the
Hurons or Algonquins fought in close ranks like our Grenadiers.  If this
use of the same arm or the same leg was only conventional, why amon<*
 some people, is the left side never preferred ? 
ON LIFE AND DEATH;
35
left  to  right.  The letters, which form the writing of
most nations, are in this way directed; such circumstance
occasions the necessity of our using the right  hand to
form them in preference to the left, the former  being as
much better adapted to this method, as the latter would
be to the contrary one; of thi» we may convince ourselves
by experiment.
  The direction of the letters from left to right, imposes
on us the necessity also  of casting our eyes upon them
in the  same direction.   From  this  habit  acquired  in
reading, arises  that of examining objects in the same
manner.
  The  necessity of similar movements  when men  are
drawn  up in line of battle, has induced almost all eations
to handle  their  weapons  with  their  right hands;  the
harmony  too which prevails in  the dances of even  the
most savage people exacts an accord in the limbs, which
they constantly  preserve by making all their principal
movements with the  right.   We might  add to these
examples a great variety  of others.
  The general movements agreed on by  society, which,
if every one were not  to execute them  in the same
direction, would be creative of much confusion ; these
movements, I say, by the influence of habit, oblige us for
our  own  particular movements to use the  limbs, which
they have brought into  action.  Hence, the members of
the right side of the body are perpetually in action either
for our own particular  wants,  or for those which we feel
in conjunction with others.
  Now, as the habitude of acting,  continually tends to the
perfection of action, we may perceive the reason, why the
right side  acquires a greater  facility in the performance
of many motions than the left.  This increased facility is
not original, but acquired. 
36
PHYSIOLOGICAL RESEARCHES
  So remarkable a difference then, in the two symmetrical
halves of the body, is not by nature  meant as an excep-
tion to the general law of harmony of action in the external
functions; for those  movements, which are executed by
the whole of the body, are the more precise in proportion
to the smallness of the  difference  existing in the agility
of the muscles of the two  sides.  How happens it that
certain animals leap from rock to rock with such admira-
ble precision, where the  least deviation  from the intended
direction, would plunge them into an abyss ? how happens
it that they run with such astonishing address on  planes,
which are scarcely equal in  breadth to  the extremities of
their limbs ?  how happens it that  the  walk of  the  very
heaviest of animals  is  never  attended  with  those  false
steps so frequent in the progression of man ?  The reason
must  be, that the difference in  their locomotive organs
in both  sides of the body is scarcely any thing, and that
in consequence there must be a constant  harmony of action
in these organs.
  He, whose general  movements,  or those of the whole
of the body are the most perfect, has the  least command
in particular over those of the right  side ; for,  as I shall
prove hereafter, the perfection of a part is  never acquired
but at the expence of that of the whole.  The child, who
should be taught to make an equal use of all his limbs,
would possess a precision in his general movements, which
he would find extremely difficult to  acquire for those of
the right hand, such as writing or fencing.
  I can  easily suppose, that some few natural circum-
stances  may  have exercised upon  us an influence in*our
choice witli  respect  to  the  direction  of those general
motions, which the habits  of society  have established.
Such  may be the slight excess of  diameter in  the  right
subclavian  artery, and the  sensation  of lassitude  during 
ON  LIFE AND DEATH.
37
digestion, which is more  perceived upon the left side on
account of the situation of the stomach, and may there-
fore  have  determined us to act at  such time  upon  the
opposite side in  preference.   Such  also  may  be  the
natural  instinct,  by  which, to  express  our  feelings  we
carry the right hand to the heart; but these circumstances
are trifling in comparison with the  very great  difference
of the movements which from  the state of civilization
exists between the symmetrical halves of the body ;  and
from this view of the subject, we cannot but regard  this
difference  as the  effect of social  convention, and  by no
means the intent of nature.
   The  voice, together with locomotion, is the  last act of
the animal life in the natural order of its functions.  Now
the greater pumber of physiologists, and Haller in particu-
lar, have indicated as the causes of want of harmony in
the  voice, the dissimilarity of  the two portions  of the
larynx,  the  inequality of  force  in  the muscles,  which
move  the arytenoid  cartilages, the same  inequality of
action in the nerveSj which are distributed  to each half of
the organ, and the  different reflection  of  sounds in the
nostrils  and  frontal  sinuses.  Without  doubt a defective
voice  must  frequently depend upon a  faulty ear ; when
we  hear incorrectly,'we sing ^incorrectly ;  but when a
correct ear is united with a want of precision in the voice,
the cause is then in the larynx.
   The most harmonious  voice is that, which the two  por-
tions of the  larynx  produce in  an  equal degree ;  where
the vibrations on one side correspond exactly in number,
strength and duration with those upon the  opposite side.*

   * The theory of wind instruments is not yet sufficiently well under-
 stood, to enable us to say, what sort of influence would be exerted  upon
 the sound by the inequality of  vibrating plates.
   (See the article Voice, in my Elements of Physiology, Vol. 2d.) 
38
PHYSIOLOGICAL RESEARCHES
In the same manner the most perfect  singing  will be
produced by two voices exactly similar in tone, compass,
and inflection.
  From the numerous considerations which I have offer-
ed, the following general conclusion may be dedueed—
namely, that one of the most essential  characteristics
of the animal life,  is a harmony of action in  the two
analogous parts, or in the two  sides of the simple  organ
concurring to the same end.   The relation which exists
between this harmony of action, which is the character
of the functions, and  symmetry of form, which is  the
attribute of the organs of the animal life, will easily be
seen.
  I wish  to  observe in finishing  this section, that in
pointing out the different  derangements, which take place
in the animal life,  from the  want of  harmony in  the
organs, I have only pretended  to assign a single isolated
cause of such derangements;  I am well aware that  a
thousand other causes besides  dissimilarity in the hemis-
pheres of the brain, may affect the operations of the mind.

   II. Of discordance of action in the organic life.

  Along with the phenomena  of the animal life, let us
now consider those of the organic life, and we shall find
that harmony has nothing to  do  with  them.  Of what
detriment would it be  to the general health of the indi-
vidual, should one of his kidneys be stronger than  the
other, and secrete more  urine; should  one of his lungs
be better unfolded than  the other, admit more venous,
and send out more  arterial blood; should a less organic
force be the lot of the salivary glands on one side than
on the other side of his body ? The simple  function, to
 which both organs concur, would not be performed  less 
ON LIFE AND DEATH.
39
perfectly.  Whenever but a slight fulness  supervenes on
one side of the liver, spleen, or pancreas, the sound part
makes up for the defect, and the function is little disturb-
ed.  The circulation also remains  unaltered  among the
frequent variations in the vascular  system of each side
of the body, whether  such  variations exist naturally, or
whether they arise from some artificial obliteration of the
larger vessels as in aneurism.
   Hence we find  those  numerous irregularities of struc-
ture, those malconformations, which as  I  have said may
be remarked in the organic life, and nothing of a morbid
nature in consequence arising.   From hence we see that
almost continual succession  of modifications, which lessen
or increase the circle of the organic functions.  The vital
powers, and their exciting causes, are continually varying,
and  thus occasion a constant instability in the functions
of the organs, for a thousand causes may at every moment
double or triple the  activity of  the circulation, and respi-
ration, increase or diminish the quantity of bile, urine, or
saliva, and suspend or augment the  nutrition of the parts.
Hunger, food, sleep, motion, rest, and the passions may all
of them  impress upon these functions so great a mobility,
as every day to make them run through a hundred degrees
of strength or weakness.
   In the animal life on the  contrary, every  thing is
uniform and constant,  the  powers of the  senses  cannot
experience  these alternate  modifications,  or at least, not
in so marked a manner.  Indeed they are at all times in a
state of relation with the physical powers, which preside
over exterior bodies; now the latter remaining unaltered,
 such variations would destroy all relative connexion, and
 thus the functions cease.
   Besides, if this mobility, which characterises the organic
 life, were the attribute of sensation—for the same reason 
40
PHYSIOLOGICAL RESEARCHES
it  would be that of all the operations of the mind.   In
such case of what would man consist ?  The perpetual
sport of every thing surrounding him, he would  find his
existence at one time little different from that of inanimate
matter, at others superior in perfection and energy to that
even which he now enjoys, allied at one time to the brute,
at another, to spiritual nature.
                   CHAPTER IV.

GENERAL differences op the TWO LIVES with respect
               TO DURATION of action.

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

    I. Of continuity  of action in the organic life.

  Prolong but little the causes which are capable of
suspending respiration, or the  circulation of the blood,
and life itself shall be  suspended, nay, even  annihilated.
All the secretions go on uninterruptedly; if they intermit
at all (and those of the bile and saliva for instance, when
not immediately  required for the purposes of digestion
and mastication, may be  said to intermit) such intermis-
sions affect the intensity of the secretion only, and not
the  entire exercise of  the  function.   Exhalation  and
absorption incessantly  succeed each  other;  the process 
ON  LIFE AND  DEATH.
41
of nutrition must be continually carried on; the double
movement of assimilation and decomposition from which
it results, can only be terminated with life itself.
  In this concatenation of the organic phenomena, each
function  depends immediately upon those which precede
it.  The  centre of them  all, the circulation, is immedi-
ately connected with the  exercise of them all,  for when
this is troubled, they languish, when this ceases, they cease
also.  Just in the  same manner the movements  of a  clock
all stop  with  the pendulum.  Nor only is the  general
action of the organic life  connected with the heart ; but
there  cannot exist a single function of this nature uncon-
nected with all the  others, for  without  secretion,  there
can be no digestion, without  exhalation  no  absorption,
vvithout  digestion  no  nutrition.  Hence  as   a  general
character of the organic functions may be  indicated con-
tinuity of action, and mutual dependence.

   II.  Of intermission of action in the organic life.

  In the exercise  of the functions  of  the animal life,
there  will be  regularly seen an  alternation  of activity
and repose, complete intermissions, and  not remissions
only.
  Fatigued by  long continued action, the senses all alike
become  for a  time,  incapable of receiving any further
impression.  The ear  loses ils  sensibility  to sound, the
eye to light, the tongue to savours, the  pituitary mem-
brane to  smells, the touch lo the qualities of bodies about
which it  is conversant, and all this for the sole reason that
the respective functions of these d liferent organs, have for
a long time been exercised.
  In  like manner, the brain fatigued by  too  great  an
effort  in  the exercise of  any of its  powers, in  order  to
             G 
42
PHYSIOLOGICAL RESEARCHES
regain its excitability, must  cease to act for a period pro-
portioned to the duration of its preceding  action.   The
muscles also after having been strongly contracted, before
they can contract anew, must remain for awhile in a state
of relaxation.   Hence in locomotion, and the  exertion of
the voice, there must be intermissions.
   Such  then is  the character peculiar to the organs of the
animal life.   They  cease to act because they have acted.
They become  fatigued, their  exhausted powers must  be
renewed.
   This  intermission is  sometimes  general,  sometimes
partial.   When a single organ, for a long time  has been
exercised, the  others remaining inactive, it relaxes and
sleeps, the others continuing to watch.—Hence, without
doubt, proceeds the reason, why  there  is no immediate
dependence among the functions  of this order on each
other.  The senses  being shut up  against  sensation, the
brain may still subsist in action, may remember, imagine,
or reflect.  In  such case the power of locomotion and the
voice also, may equally well be exercised, and  these in
like manner may remain unexercised, and the activity of
the senses be in no-wise impaired.
   Thus the animal  at  will may  fatigue any one of the
parts of this life, and  on this very account, such parts
must all of them possess a capability of being relaxed, a
power of repairing  their forces  in an isolated  manner.
This is the partial sleep of the organs.

III. Application of the law of intermission of action
                 to  the theory of sleep.

   General sleep is the sleep of all the parts.  It follows
 from that law, which with respect to the functions of the
 animal  life, enchains intermission with periods of action, 
ON LIFE AND DEATH.
43
from that law, by which this life is particularly distinguish-
ed from the organic life.
  Very numerous varieties are remarked in this periodi-
cal  state, to which  all animals are subject.   The  most
complete sleep is that in which the outward life is entirely
suspended.  The least perfect  sleep is that which affects
one  organ  only ; it is that of which  we  have just  been
speaking.
  Between these two extremes there  are many interme-
diate states.  At times  perception, locomotion, and  the
voice only are suspended ;  the imagination, the  memory,
and  the judgment  remaining in action.   At other times,
to the exercise of the latter  faculties  are added those of
the locomotive organs and  the  voice.—Such is the sleep,
in which we dream,  for dreams are nothing more than a
portion  of the  animal life  escaped from  the  torpor, in
which the other portion of it is plunged.
  Sometimes but very few of the senses have ceased their
communication  with external  objects.  Such  is that spe-
cies of somnambulism, in which to the action of the brain,
the muscles, and the larynx, are added  the very distinct
actions of the ear and the sense of touch.*

  * The  action of the brain is far from being preserved in somnambulism.
The thread of ideas, on the contrary, is completely broken, and this is
the  most striking character which distinguishes  every  kind of sleep
from wakefulness.   The mind then cannot reflect upon the sensations
which it receives, it abandons  itself successively  and without any
resistance to all those which are presented, without examining the con-
nexion which they can have between  them.  In ordinary  sleep, the
senses are almost entirely blunted, the mind receives no other sensa.
tions than those which  have been derived from  memory; but  they
present themselves  in a confused  manner, without order  and  in such a
way  as  often to form the most strange and  incoherent  images. In
somnambulition the action of many senses,  and that of hearing in
particular is preserved ; the judgment of the sleeper can then exercise
itself not only upon its reminiscences, but also upon the impressions 
44           PHYSIOLOGICAL RESEARCHES
   Sleep  then cannot  be considered  as  a constant  and
 invariable state with regard to its phenomena.—Scarcely
 ever do  we sleep in  the  same  manner  twice  together.
 A  number of causes  modify in  applying to a greater or
 less portion of the animal life the  laws  of intermission
 of action.  Its different degrees should be marked by the
 different functions, which these intermissions affect.
  But the principle of it is every where the same from
 the simple relaxation of a muscle to the entire suspension
 of the whole of the  animal  life.  Its  application, how-
 ever, to the different  external functions,  varies without
 end.
  These ideas on sleep are different, no doubt,  from thai
 narrow system, where  its cause exclusively placed in the
 brain, in the heart, in the large vessels, or in  the  stomach,
presents an isolated and frequently an illusory phenome-
non, as the  base of one of the  great modifications of
life.
  And what is the reason why light and  darkness in the
natural  order  of things, coincide so  regularly with  the
activity or intermission of the  external functions ?   The
reason is  this, that during the day a thousand  means of
excitement  perpetually surround the  animal, a thousand
causes  exhaust the powers of his sensitive and locomotive
organs, fatigue them,  and prepare  them  for a state of
relaxation,  which  at  night is  favoured by  the absence
of every  kind of stimulus.   Thus,  in the actual  state of
which are transmitted to it  from without.  The sound of a bell or a
drum, being heard while we  are in a dream, will immediately modify it.
In this way  a person may gain the attention of a somnambulist, and as
the latter possesses the use of his voice, it will be seen  by his answers
that his ideas can be directed at will, and led in this way wherever it
is wished; for  the impressions that he  receives from without, being
stronger than those which come from  memory, he will almost always
obey the first. 
ON LIFE AND DEATH.  '            45
society, where this order is'in part inverted, we assemble
about us at evening, a variety of excitants, which prolong
our waking moments, and  put off until towards the first
hours of daylight, the intermission of our animal life, an
intermission, which we  favour besides by removing from
the place of our  repose  whatever might produce sensa-
ion.
  We may for a certain time, by multiplying the causes
of excitement about them,  withdraw  the  organs of the
animal  life from  this law of intermission, which should
naturally  cause  them to sleep ;  but at last they  must
undergo its influence, and nothing can any longer suspend
it.  Exhausted by watching, the soldier slumbers at the
cannon's side,  the slave under the whip, the criminal in
the midst  of torture.
  We must  carefully make a distinction, however, be-
tween the natural sleep, which is the effect of lassitude,
and that,  which is the  consequence of some affection of
the brain, of apoplexy, or concussion,  for instance.  In
the latter case the senses watch, receive impressions, and
are affected as  usual, but these impressions are not per-
ceived by the diseased sensorium; we cannot be conscious
of them.   On the contrary, in ordinary sleep  the senses
are affected as much, or even more than the brain.
   From what  has  now been said,  it  follows,  that the
organic life, has a longer duration than the animal life.
In fact the sum of the periods of the intermissions of the
latter, is almost equal to that of the times of its activity.
We live internally almost double the time that we exist
externally. 
46           PHYSIOLOGICAL RESEARCHES
                   CHAPTER V.

GENERAL DIFFERENCES OF THE TWO LIVES WITH RESPECT
                      TO HABIT.

  Another of the great distinguishing characters of the
two lives of the animal, consists in the  independence of
the one, and in the dependence of  the other on habit.

           I. Of hahit in the animal life.

  In the animal  life every thing  is  modified by  habit.
The functions of this life, whether enfeebled or exhausted
by it, according to the different periods of their activity,
appear to assume  a variety of characters  : to estimate the
influence of habit, it is necessary to consider  two things
in the effect of all sensation, the sentiment, or immediate
feeling, which we have of external objects, and the judg-
ment  which  is the result of one  or more  comparisons
made with  respect to them.  An air, for instance, strikes
the ear; the first  impression made  upon the organ is, we
know not why, agreeable or painful.  This is sentiment—
at present let us  suppose the  air to  be  continued.  We
may now endeavour to appreciate the different sounds of
which  it is composed, and to  distinguish their accords.
In this we  exercise the judgment.  Now, on these two
things, the action of habit is inverse.   It enfeebles  our
sentiment of  things, it improves our  judgment of them;
the more we  regard an object,  the less are we sensible of
its agreeable  or painful qualities, the better, at the same
time, may we judge of its attributes. 
ON LIFE  AND DEATH.
47
             II.  Habit blunts the sentiment.

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

  * Pleasure and  pain  are always absolute sensations, but they may
depend upon relative circumstances ; that degree of cold, for example,
does  not  incommode  the inhabitant of Spitzbergen, which would  be
very  painful to a man  from a  temperate  climate.   In order to under-
stand how habit  produces these effects, we must recollect  that the
repetition of the same sensations on the same part exhausts at length the
sensibility of it.   Hence we may conceive how the  contact of a body
upon a living  surface  may cease to be painful, while  any division or
solution of continuity of one of our organs  will be always more or less
so, because the nerves that  are  divided  are unaccustomed to this
sensation, and still possess their whole sensibility.  The sense of sight
furnishes us with a striking example of sensibility  being  exhausted  by
the continuation of the sensation ; if we look for a long  time with the
same eye  upon a white surface with a red spot in the middle of it, and
then  look upon a part that is  all white, we shall perceive there a
greenish spot; for the part of the retina which has been a long time in
contact with the red rays, loses the peculiar sensibility that enables it
to transmit this sensation perfectly ; and of all the  coloured rays which
compose the white rays that  now go to it, it  transmits only  those to
which it is unacquainted; hence results the sensation of green. 
48
PHYSIOLOGICAL RESEARCHES
 eight days  afterwards  he is no  longer  sensible of it.
 Here we have comparative pain.  Whatever destroys the
 texture of the organ is always  productive of an absolute
 sensation; the simple contact of bodies at no  time  pro-
 duces any other than a relative sensation.
   Hence it  is evident that the domain of absolute pleasure
 or pain, is much less extensive than that of these  feelings
 when relative.  The very words agreeable, or  painful,
 imply a comparison made between the impression receiv-
 ed  by the senses, and the state of mind  on  which  it is
 received.   Now it is manifest that we could have referred
 only to relative pain and  pleasure, as being submitted to
 the influence of habit.  On these we shall occupy  our-
 selves awhile.
  And to shew that  they are  gradually  worn away by
 habit as we have said,  to the point of  indifference, a
 variety of proofs may be adduced.  Every foreign body
 in contact for the first time, with a mucous membrane, is
 creative of a disagreeable sensation, which by repetition,
 is diminished, and at last becomes altogether impercepti-
 ble.   Pessaries in the vagina,  tents in the rectum, the
 canula made use of for tying polypi of  the nose, or the
 uterus,  bougies, in  the  urethra, in the  oesophagus, or
trachea, styles and setons in the lachrymal passages,  pre-
 sent us every day with  these phenomena.  The impres-
 sions of which the cutaneous organ is the seat, are all of
 them subjected to  the same  law.  The sudden passage
 from  cold to heat, or from heat to  cold, is  always  the
occasion of a disagreeable sensation, but  such  sensation
 gradually  and at last entirely disappears, if the tempera-
 ture of the atmosphere  be within a certain range  and
 constant.  From hence proceed those various sensations,
 which we  have from  the change of climate, or  season.
 Similar phenomena in the same way are the result of  our 
ON  LIFE  AND DEATH.
49
successive perceptions of the dry  or humid, the  soft, or
the hard  qualities  of bodies, and in  general  the  same
may be said of  all our relative sensations, of what kind
soever.
  With respect to pleasure, we  shall repeat what we
have said  of pain.   The perfumer  and the  cook are  by
no  means sensible  in their several professions of those
pungent enjoyments  of which  they are dispensers.  In
them the habit of  perceiving has blunted the sentiment.
The same is the case with all agreeable  sensations what-
ever.  Delightful views and delicious  music are  produc-
tive of a pleasure,  the vivacity of which is soon lessened j
for harmony and beauty if  they for a  long time continue
to  solicit  our  attention,  are  successively  the  sources
of pleasure, of  indifference, of  satiety,  nay even of dis-
gust and  aversion.   This  remark  has been felt by all;
Philosophers and Poets have all of them turned it to their
account.
   From whence arises this facility, which our sensations
have of undergoing so many different, so many contrary
modifications ?  To conceive it, let us first  remark that
the centre of these revolutions of pleasure, of pain, and of
indifference, is by no means seated in the organs, which
receive or transmit the sensation, but  in the soul.  The
affections  of the eye, of the tongue, and the  ear, are at
all times  the  same from the same objects, but  to these
affections  at different times, we attach a variety of senti-
ments.  In the  second place we  shall observe, that the
action of the  mind in  each several sentiment of pain or
pleasure, which has been the effect of a sensation, consists
in  a comparison   between this  sensation,  and that  by
which it has been  preceded, a comparison, which  is not
the result of  reflection, but the involuntary effect of the
first impression of the object.  Now,  the greater the dif-
              7 
50
PHYSIOLOGICAL REsLARCHES
 ference between the actual and the past impression, the
 livelier will  be the sentiment.  The sensations which
 affect us the most, are those which we never before have
 experienced.
   The consequence  is,  that in proportion as the  same
 sensations are repeated, the less impression do they make
 upon us, because the comparison between the present and
 the past becomes less sensible.  Pain  then and pleasure
 naturally tend  to their  own annihilation.  The art of
 prolonging our  enjoyments, consists in  varying  their
 causes.  Indeed were I to regard the laws of our material
 organization only, I might  almost say, that  constancy is
 but one of the  happy dreams of  the  poet, and that the
 sex to which we at present bend, would possess but a very
 weak hold upon our attentions were  their charms too uni-
 form; I might almost assert that  were every female cast in   *
 the same mould, such mould would be the tomb of love.
 But here let us forbear  to insist upon the principles of
 physiology, where they  tend to the destruction of those
 of morality.   The one, and the other  are equally solid,
 though  sometimes at variance.  We  shall only notice,
 that at times the former  unhappily are our only guides.
 It is then, that love disappears, with the pleasure  which
 it has procured, and leaves us but disgust.   It is then, that
 recollection too often carries us aside from our duties in
 rendering uniform that which we feel and that which we
 have felt, for such appears to be the essence of physical
happiness,  that past  pleasure enfeebles the attraction of
that which we enjoy.
  The  consequences are  clear.   Physical pleasure is
 nbthing but a  comparative sentiment;  it  ceases to  exist
when  uniformity supervenes between the actual and  past
impression.   By means  of this uniformity  habit must
bring  down pleasure to  indifference : Such is the secret 
ON LIFE AND DEATH.
51
of the very great  influence  which it exercises over our
enjoyments.
  Such also is  its  mode of action  on our pains.  Time
flies, it is said, and carries away sorrow; time is the true
remedy of grief; and  wherefore?  The reason  is, that
the more sensations it accumulates upon that which has
been painful, the more does it enfeeble the sentiment of
comparison  between what we are, and what  we were.
At  last this sentiment  becomes extinct.  There are no
eternal sorrows.

          III. Habit improves the judgment.

  I have just now  proved  that the  sentiment is enfeebled
by the effect of habit.   It is as easy to demonstrate, that
habit improves and enlarges the judgment.
  When,  for the  first  time, the  eye  wanders over  an
extensive country, or the ear is struck by a succession of
harmonious proportions ; when the taste, or the smell for
the first time are affected by any very  compound savour
or scent, there arise from these sensations only confused
and inexact ideas.  We represent to ourselves the whole,
its parts escape us.  But let  these  sensations,be repeat-
ed, and in proportion as they  are  so, will the judgment
become precise and  rigorous, and  the knowledge of the
object be perfected.
  Let us for instance observe the man, who a stranger to
theatrical  amusement of every kind is  introduced to the
Opera.  He will have but a very imperfect  notion of it.
The dancing, the music, the  scenery, the actors,  the
splendor of the whole  will be all  confounded within his
mind  in a  sort of delightful chaos.   But  let  him be
present at many representations,  and  whatever in this
charming whole belongs to the several  arts,  will assume 
52           PHYSIOLOGICAL RESEARCHES
its separate  place.  He will  have seized its detail, may
form a judgment of it, and  this  he  will  do  the more
accurately in proportion to his opportunities of observa-
tion.
  The above example affords us  an  abridgment of the
picture of the  man, who  enjoys  for the first time the
spectacle of  nature.   The child, at its  birth, is  only capa-
ble of general  impressions, but habitude,  by gradually
blunting  these  impressions,  enables  him  to  seize  the
particular attributes of bodies,  and  teaches him to see, to
hear, to smell, to taste  and to touch,  by  making  him in
each sensation  descend successively  from  the confused
notion of the whole to the precise idea of its parts.  The
animal life  needs education,  and this is  one of its great
characters.
  Habit then while it hebetates our sentiments, improves
our judgments  of things.   An example will  render this
truth indisputable.  Most persons may recollect  that in
traversing a meadow, embellished  with  a  variety of
flowers, they have been  sensible of a general fragrance
only, the confused assemblage of all the particular odours
which are exhaled from each  individual flower ;  but in a
short time from habit this first sentiment is weakened, it
is soon afterwards  altogether effaced.  They then may
have distinguished the  odour of each particular plant, and
formed a judgment at first impossible.
   The two contrary operations thus of habit on our senti-
ments and judgments, tend as we see to one common end,
the improvement, namely, of  the animal  life.

           IV.  Of habit in the organic life.

   Let us at present compare the  above-mentioned phe-
nomena with those of the organic  life, and the latter we 
ON LIFE AND DEATH.
53
shall see  as  constantly withdrawn from the influence of
habit, as  the  former are subject  to it.—Habit has never
modified  the  circulation, or respiration, has never changed
the mode of the processes of exhalation, absorption, or
nutrition.  A thousand  causes would every day endanger
our very existence, were these essential functions under
the influence of habit.
   The excretion of the urine and fecal matter may, never-
theless, be suspended, accelerated,  and return  according
to laws determined by habit.   The action of the stomach
with  respect to hunger, and  its  contact  with certain
aliments, appears  also  to be subordinate to habit; but
here let us remark, that these different phenomena hold,
as it  were, a middle place between  the  two  lives, are
found on the limits of the one and the other, and partici-
pate almost as much of the animal as the organic life.  In
fact, they all of them take place  on mucous membranes,
a species of  organ, which being  at all times  in relation
with  bodies foreign to our nature, is the seat of an inward
tact, in every  way analogous to  the  outward  tact of the
skin.  The two must be necessarily subject to the same
laws.—Can we be  astonished at the influence of habit on
both  of  them ?
   We cannot, and let us remark  also, that the greater
part  of  these phenomena, which begin  as  it were, and
terminate the  organic  life, are  connected with  motions
essentially  voluntary,  and  in  consequence,  under the
dominion of the animal life.
   I shall not here enlarge on the numerous modifications
of power, taste, and desire,  which have  their source  in
habit.  I refer to the numerous  works which  have con-
 sidered its influence in a different point of view from that
 which I have indicated. 
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PHYSIOLOGICAL RESEARCHES
                   CHAPTER VI.

GENERAL DIFFERENCES OF THE TWO LIVES WITH RESPECT
               TO MENTAL AFFECTION.

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

I. Whatever relates  to the understanding belongs  to
                   the animal life.

   It would  be useless for me to insist  on  proving that
meditation,  reflection, the judgment, and all  the  opera-
tions of the mind depending upon an association of ideas
are under the dominion of the animal  life.  We judge
from impressions formerly or actually received, or from
those which we ourselves  create.  Perception, memory,
and the imagination are the principal bases,  on  which are
founded  the operations of the mind, but these very bases
 themselves repose upon the action of the senses. 
ON LIFE AND DEATH.
55
  Let us suppose a man at his birth to be deprived of all
that exterior apparatus, which is destined to establish his
connexions with surrounding objects; such man will not
altogether be the statue of Condillac, because, as we shall
see hereafter, other causes besides the  sensations, may
occasion within him the motions of the animal life; but
at least will  he not be able, a stranger as he is to every
thing surrounding him, to form any judgment with respect
to things.  The intellectual  functions with  him will be
null; volition, which is  the  consequence of  these func-
tions, will  not have place, and consequently, that very
extensive class of motions which  has its immediate  seat
in  the  brain, and which  itself is  but  an effect  of the
impressions made  there, will  in nowise belong to him.
   It is by means of the animal  life that man is so great,
so superior to the beings, which surround him ; by means
of  this that he possesses the  sciences, the arts, and every
thing which  places him  at a distance  from the  gross
elements under which we  represent brute matter; by this
that he  approaches spirituality; for industry and  com-
merce, and  whatever  enlarges the narrow circle within
which the efforts of other animals are confined, are exclu-
sively under  the  dominion of the animal life of man.
   The  actual state of  society then is nothing but a more
regular  development,  a  more  marked  perfection of the
exercise of  the different functions of this life; for one of
its greatest  characters  as I shall hereafter prove, consists
in  its capability of being unfolded, while, in the organic
life, there does not exist a part, which in the least degree
may pass the limits which are set to it by  nature.  We
live organically in as  perfect, in as regular a  way, when
infants,  as when men; but what is the animal life of the
 child compared with  that of the man of thirty  years  of
 age ? 
56           PHYSIOLOGICAL RESEARCHES

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

II.  Whatever relates to the passions belo?igs to the
                     organic life.

  My present  object is  not to  consider  the   passions
metaphysically.   It little  matters, whether they  be  all of
them the  modifications of a single passion, or dependent
each of them upon a separate  principle.   We shall  only
remark, that many physicians in discussing  their influ-
ence  on the organic  phenomena, have not  sufficiently
distinguished them from the sensations; the latter are the
occasion of the passions, but differ from them  widely.
  It is true that anger, joy, and sorrow,  would not affect
us,  were we not to find their causes in our  connexions
with external objects.  It is true  also, that the senses are
the agents of these relations, that  they  communicate the
causes of the  passions, but in this they  act as simple
conductors only, and  have nothing in common  with the
affections, which they produce ;  for sensation of every
kind  has its centre in the  brain,  sensation of  every kind
supposing impression and perception.   If the  action of
the brain be suspended,sensation  ceases; on the contrary, 
ON LIFE AND DEATH.
57
the brain is never  affected by the passions;  their seat is
in the organs of the internal  life.*
   It is undoubtedly surprising that  the passions, essen-
tially  as  they  enter  into our relations  with the beings
which  are placed  about  us, that modifying as they do at
every moment these relations, that animating, enlarging,
and exalting the  phenomena of the animal  life, which
without  them would be nothing but a cold  series  of intel-

  * Bichat, in this paragraph, seems to say that the perceptions, which
produce in us the  passions, go directly and without the intervention of
the brain,  from the senses to the organs which he supposes to be affected
by them.   We cannot believe that such was his idea.  The paragraph
which follows must aid us in understanding it, and we shall endeavour
to elucidate it by means of an example.
  A certain event happens; a man is  informed of it by means of his
senses; he  examines the event in itself, and its relations with antecedent
and future events ; his judgment weighs the various consequences of it,
and shows them to be very disadvantageous to him.  Here, as Bichat calls
it, is a cold series of intellectual  phenomena, which  would take place
in the individual, whoever the man may  be who is affected by the event
to which he has given  his attention.  It is found that the man  who js
injured  is  himself;  then, from a knowledge of this  only, his heart is
sympathetically affected ;  its motions become more rapid and stronger,
they send  to the brain a greater quantity of blood, and this increase of
habitual excitement in the organ of thought, produces a kind of mental
attention in relation to the event  that has taken place.
  Thus, without the part that the heart  has taken in  it, this man would
have seen  with  the most perfect  iudifference an event most disastrous
to himself; for  without even supposing anger, the  least sentiment of
sadness being a passion,  we cannot believe that he is affected with it,
if his liver, stomach or spleen  are  not at the  moment in a particular
state.  But does not every thing on the contrary lead us to believe that
anger exists before the agitation of the heart, and that this is the effect
of it and not the cause ?   This agitation of the heart without doubt, by
sending to  the brain a greater quantity of blood than usual, contributes
in its turn  to develop  and support the kind of alienation which accom-
panies anger; but it is necessary  that the passion should  already exist,
since a favourable event, by producing  as rapid motions of the heart,
will produce nothing similar.
                 3 
53         PHYSIOLOLOGICAL RESEARCHES

lectual  movements ;  it  is astonishing,  I  say, that the
passions should neither  have their  end, nor  beginning
in the  organs of this life, but on the contrary, that the
parts which  serve for the internal  functions,  should be
constantly affected by  them,  and  even occasion  them
according to  the state in which  they are found.   Such
notwithstanding is the result of the  strictest observation.
   I  shall first  observe, that the effect of every kind of
passion is at all  times  to produce  some change in the
organic  life.   Anger accelerates  the circulation of the
blood, it multiplies the efforts of the heart.   The passion
of joy has not  indeed so marked an influence  upon the
circulation, but alters it notwithstanding, and  carries  it
lightly  towards the skin.   Terror  acts inversely;  this
passion being characterized by a feebleness in the vascular
system, a feebleness,  which in hindering the blood  from
arriving at the capillary vessels, occasions  the  paleness
which at such time  is  so  particularly  remarked.   The
effects of sadness and sorrow are nearly  analagous.
   So great indeed is  the effect which the passions  occa-
sion  upon the organs  of  the circulation,  as even to arrest
them altogether in their  functions, where the affection is
very powerful.   In this way is syncope  produced, for the
primitive seat of syncope is always,  as I shall soon prove
it  to be, in the  heart, and not in the brain.  In this the
latter organ ceases to  act, only because it ceases to receive
the excitant necessary to its action.   Hence also may hap-
pen  death itself, the sometimes  sudden effect of extreme
emotion, whether  such  emotion as in anger  so far  exalts
and exhausts  the powers  of the circulation, as not to  leave
them any further excitability, or whether as in  the death
occasioned by excessive  grief, the powers at once exces-
sively debilitated,  are no longer capable of  returning to
their usual condition. 
ON  LIFE AND DEATH.
519
  If the total and instantaneous cessation of the circula-
tion be not occasioned by this debility, a variety of lesions
in the blood  vessels may be, notwithstanding,  the effect
of it.   Desault has remarked that  diseases of the heart,
and aneurisms of the aorta, were augmented in number
during the revolution, in proportion to the evils which it
produced.
  Nor  does  respiration  depend less  immediately  upon
the  passions ;  that oppression, that  anxiety, and sense of
suffocation, which is the sudden effect of profound sorrow,
must imply in the lungs a remarkable change and sudden
alteratian.  In that very  long  series of chronic or acute
affections,  the sad  attribute of the pulmonary system,
must we not  often look to the passions to find the princi-
ple  of the disease?
  And that lively sensation at the  pylorus under strong
emotion, that ineffaceable impression which sometimes
remains there, from whence succeed the schirri of which
it is the  seat, that sentiment of  stricture, as it were,
about the stomach, about the cordia in particular; under
other circumstances those spasmodic vomitings, which
sometimes follow the loss of a beloved object,  the news
of a fatal accident, or  any kind of trouble,  the cause of
which are the passions; that  sudden  interruption of the
digestive  phenomena either in consequence of agreea-
ble  or disagreeable news,  those affections  of the bowels,
those organic  lesions of the intestines,  of the  spleen
observed  in  cases of melancholy, or hypochondria, dis-
eases which are always preceded by sad forebodings and
the darker affections of the mind; do not all these indicate
the very strict connexion of the digestive viscera with
the state of the passions ?
  They do ;  and the secreting organs have not a less
connexion with  them.  Sudden fear  suspends the course 
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PHYSIOLOGICAL RESEARCHES
of the  bile,  and is the occasion of jaundice;  sudden
anger is often the origin of- bilious fever.   In a  state of
sorrow or joy, sometimes even in that of admiration, our
tears flow abundantly: the pancreas is not less frequently
affected in hypochondria.
  But the functions of the circulation, of digestion, respi-
ration and  secretion, are those  which are most  directly
under the influence  of the passions;  those of exhalation,
absorption and nutrition  appear to be  less so.  Doubtless,
the reason of this is, that these functions have  not as the
former any principal focus, or essential viscera, the  state
of which may be compared  with that of the mind.  Their
phenomena disseminated throughout all the organs belong
exclusively to none, and cannot be observed as well as
those, the effects of which are confined within a narrow
compass.
  Nevertheless, the alterations,  which these functions
experience are  not less real, do not become less apparent
after a certain time; let the man, whose hours are marked
by sorrow, be compared with him, who  lives in  peace of
mind,  and  the  difference of the  process  of nutrition in
the one and in  the other will easily be seen.
  Let us, for a  moment, approximate  the times, when the
terrible passions of sorrow, of fear and  revenge seemed
to brood over our country, and those, when safety and
abundance  continually supplied us with the  gayer ones so
natural to us  ; wre may then recall what at the two periods
were the outward  appearances of our countrymen, and
appreciate the influence  of  the passions on the process of
nutrition.  The very expressions which are  continually
in our  mouths that such  a one is dried up with envy,
preyed upon by remorse, consumed and  wasted away
with sorrow, do not even these announce how much the
nutritive functions are modified by the passions ? 
ON LIFE AND DEATH.
61
  I know not for what reason the powers of absorption
and exhalation should not be subject to the same influence,
though they appear to be less so ;  may not dropsies, and
all infiltrations  of the cellular  membrane, the  peculiar
vices of these two functions, depend  on mental affection ?
  In the midst  of these disturbances, of these partial or
general revolutions which  are produced by the passions
in the organic phenomena, let us consider the actions of
the animal life; they constantly remain unaltered, or if
they do experience any  derangement, such derangement
has ever its source in the internal functions.
  From so many considerations we may  conclude that it
is upon the organic and not upon the animal life that  the
passions exercise  their influence.   Accordingly, whatever
serves  to paint  them must relate to  the former.   Of this
assertion, our gestures which are the mute expressions
both of the sentiment and understanding are a remarkable
proof.   Thus if we indicate any operation of the memory,
imagination or judgment, the hand is carried to the head;
do we  wish to  express  either love  or hatred, or joy  or
sorrow, it is to  the seat of the heart,  the stomach or intes-
tines, that it  is  then directed.
  The actor, who should mistake in this respect, who in
speaking of sorrow should refer his  gestures to his head,
or carry them to his heart, for the purpose of announcing
an effort of genius, would be ridiculed for a reason which
we should better feel than comprehend.
  The very  language of the vulgar, at a time when  the
learned referred to  the  brain, as the seat of the soul,
affections of  all kinds, distinguished  the  respective attri-
butes of the  two lives.   We have always said  a strong
head, a head  well organized to denote perfection of mind;
a good heart, a sensible heart, to indicate proper  feeling.
The expressions of fury  circulating in the  veins, and 
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PHYSIOLOGICAL RESEARCHES
stirring up the bile ; of joy making the heart leap,  of
jealousy distilling  its passions into  the heart, are by no
means poetical expressions, but  the enunciation of that
which actually takes place in nature.  In this way do all
these expressions,  the language of the internal functions
enter  into our poetry,  which  in  consequence is  the
language of the passions or  the organic life, as ordinary
speech, is that  of the understanding or the  animal  life.
Declamation holds a middle place between the two, and
animates the cold language of the brain by the expressive
language of the inward organs.
  I  shall even venture to assert  that  anger and  love
inoculate, if I may so express myself, into the humours,
into  the saliva particularly,  a radical vice, which renders
dangerous the  bite of animals at such times ; for  these
passions do really  distil  into the  fluids a poison, as we
indicate  the  fact  by  our  common expressions.   The
violent passions of the nurse have frequently  given her
milk a pernicious quality, from whence disease has fol-
lowed to the child; and  in the same way shall we explain
from the  modifications  wiiich the  blood  of  the mother
receives under strong  emotion,  the manner, in which
these emotions operate  on  the  nutrition, the  conforma-
tion, and  even on the life of the foetus.  And not  only
do the passions essentially influence the organic  func-
tions, in affecting  their respective  viscera, but the  state
of these viscera, their lesions, the variation of their forces
concur in a decided way to  the production of the passions
themselves.  Their relations with age and temperament,
establish incontestably this fact.
  Who does  not know for  instance, that the  individual
of the sanguine temperament, whose expansion of lungs
is great, whose circulatory  system is large  and strong;
who does not  know  that such a man is possessed  of a 
ON LIFE AND DEATH.
63
disposition to anger and violence? that when the bilious
system  prevails,  the passions  of envy  and hatred  are
more particularly developed ?  that when the lymphatic
system is pronounced, are pronounced also the inactivity
and dulness of  the individual?
  In general that which characterises any particular tem-
perament, consists in a correspondent modification on one
hand  of the passions, and on  the  other  of the  state of
the organic viscera.   The  animal life is almost always a
stranger to the  attributes of the temperaments.
  The same may be said  of age ;  the weakness of  the
organization of the  child coincides with his timidity.
The development of the pulmonary and vascular  system,
with the courage  and temerity of the youth; that of  the
liver, and the gastric system  with the envy, ambition and
intrigue  of manhood.
  In considering  the  passions as  affected  by climate and
season,  the same  relations are observed  between  them
and the  organic functions; but physicians have sufficiently
noticed  these analogies, and it would be useless to repeat
them.
  At present, if from  man in  a state of health, we look
to man in a state  of disease, we shall see that the lesions
of the liver, of the stomach, of the spleen, the intestines
and heart produce a variety of alterations in our affections,
which all of them cease together  with their causes.
  The ancients,  better than our modern mechanicians,
then were  acquainted with  the  laws of  the economy,
in supposing that our bad  affections were evacuated  by
purgatives,  together  with  the  noxious humours of  the
body.   By disembarrassing the primae viae they  got  rid
of these affections.  In fact how dark  a tint does  the
fulness of the gastric  viscera cast  upon the countenance !
the errors of the  first physicians on the  subject of the 
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PHYSIOLOGICAL RESEARCHES
 atrabilis, were a proof  of the precision of their observa-
 tions on the connexion  of these organs with the state of
 the mind.
   In this way every thing tends to prove, that the organic
 life, is the  term, in which the passions end, and the centre
 from whence they  originate.   But we shall  be asked
 perhaps, why vegetables, which live organically, do not
 offer  any vestige of them ? the reason seems  to  be, that
 besides their want of the natural excitants of the passions,
 namely the  external apparatus of the senses, they  are
 wanting also in those internal organs, which concur most
 especially  to their  production,  such as  the  digestive
 system, that of the general circulation, and that of the
 great secretions, which are remarked in animals.
   Such are the reasons also  why  the passions are  so
 obscure in  the Zoophytes, in  worms, &c. and why  in
proportion  as the organic life  becomes more  simple  in
the series of  animals, and loses its important viscera, the
passions are less observable.

 III.  The passions  modify  the actions of the animal
        life  though seated in the organic life.

   Although the passions are  the  especial attributes  of
 the organic life, they nevertheless exert an influence over
 the animal  life, which it is necessary to examine.   The
 muscles of  volition  are frequently brought  into play, and
 their  actions sometimes exalted, sometimes lowered by
 them ; the  strength for  instance of the man in  anger is
 doubled, and tripled ; is exercised vvith  an energy,  of
 which he is not  himself the master.  The source of this
 augmented  power is manifestly  in the heart.
   This organ, as I  shall prove hereafter, is the  natural
 excitant of the  brain, by means of the blood, which it 
ON  LIFE AND DEATH.
65
sends thither.  The energy of the cerebral  action is  in
proportion to the energy of the stimulus applied to it, and
we have seen that the effect of anger is to impress a great
vivacity upon the circulation ;  hence, a larger quantity of
blood than usual is thrown upon the brain  in a given time.
The consequence  is  an effect analogous to that which
happens in the  paroxysm of ardent fever,  or the immode-
rate use of wine.
   It is then, that the brain being excited strongly, excites
as strongly the muscles which are submitted to its influ-
ence ; accordingly their motions must be  involuntary, for
the will is a stranger to those spasms, which are determin-
ed by a cause which irritates the medullary organ.  Such
cause may be a splinter of bone, blood,  pus, the handle
of a scalpel  as  in  our experiments ;  in short of various
kinds.
   The analogy is  exact, the blood being transmitted to
the brain  in  greater quantity than  usual, produces upon
it the  effect of the different excitants above mentioned.
In these different motions theu,  the brain is passive ; it
engenders indeed  at all  times the necessary irradiations
for producing such motions, but these  irradiations in the
present instance are not the effect of the  will.
   It may  be observed also,  that under  the influence of
anger,.a constant relation exists  between  the contractions
of the heart and the locomotive organs; they both  increase
at the same time, and at the same time resume their equi-
librium.   In  every other case on the contrary  there is
no appearance  of this relation ; the action of the heart is
uniformly the same, whatever the affection of the muscu-
lar system.   In convulsion  and palsy, the  circulation is
neither impeded nor accelerated.
   In the passion of anger, in  fact, we  see the very mode
of the influence, which the organic life exercises over the
              9 
66
PHYSIOLOGICAL RESEARCHES
animal life.   In the passion of fear also, where on the one
hand the enfeebled heart directs a less quantity of blood,
and consequently a  smaller  cause of excitement to the
brain, and where on the other hand  a debility  may be
observed in  the external muscles, we  may perceive the
connexion of cause and effect.  This passion offers in the
first degree the phenomenon, which in the last degree is
shewn by those lively emotions, which suspending alto-
gether the efforts of the heart, occasion  a sudden cessation
of the animal life and syncope.
  But in what way shall we  account for those modifica-
tions  of the motions of the  animal  life,  which  are the
effect  of the passions ?   In what way shall  we  explain
the cause of those infinite varieties, which succeed each
other  in the moveable picture of the face?
  All the muscles which are  the agents of these motions
receive their nerves  from the brain and  lie under the
influence of the  will.   What is  the  reason  then,  that
when acted on  by the passions, they cease to do so, and
enter  under the class of those motions of the organic life,
which are put forth without our direction or conscious-
ness.   The following if I mistake not is the best explana-
tion of the fact.
  The most numerous sympathies exist between the
internal  viscera,  and  the  brain or its different, parts.
Every step which we make  in practice presents  us with
affections*of the brain originating sympathetically from
those  of the liver, stomach and' intestines.   Now as the
effect of every kind  of  passion is to produce a change of
power in one or the other of these viscera, such change
will sympathetically excite either the whole of the brain
or some of its parts, whose re-action  upon the muscles,
which receive from thence their nerves, will produce the
motions, which are then observed.  In the production of 
ON LIFE AND DEATH.
67
these motions the cerebral organ accordingly must be pas-
sive, it is active only when the will presides over its efforts.
  The effects indeed of the passions  are  similar to those
diseases of the internal  organs, which  by sympathy are
the causes of atony, palsy, and spasm.
  But perhaps the inward organs act upon the voluntary
muscles, not by  means of the immediate  excitement of
the  brain, but by direct nervous communication.   Of
what importance to us  is the manner ?  We  are  not at
present  occupied  on the so much  agitated question  of the
manner of sympathetic communication.
  The essential thing is the fact itself.   Now in this  fact,
there are two things evident; the affection of an internal
organ by the passions, and  secondly a motion produced
in  consequence of such affection  in muscles, on  which
this organ in the common  series of the phenomena of
the two lives has no kind of influence.   This  is surely a
sympathy, for between it, and those with which convul-
sion, or spasm of the face  present us, when  occasioned
by any  lesion of  the phrenic  centre, or the stomach, the
difference is only in the cause, which affects the internal
organ.
   Any  irritation of  the  uvula,  or the pharynx  con-
vulsively  agitartes the  diaphragm.   The too  frequently
repeated  use of  fermented  liquors  occasions  a general
trembling of the body.  But that which  happens in  one
mode of gastric affection, may happen in another.  What
matters it, whether the stomach or liver be irritated by
passion or by some material  cause ?  It is from the affec-
tion, and not from the cause of the affection that  results
the sympathy.
   Such in  general is the manner in which the passions
withdraw  from  the empire  of the  will, those motions
which by nature  are voluntary.  Such is the  manner in 
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PHYSIOLOGICAL RESEARCHES
which  they  appropriate  to  themselves,  if I  may so
express myself, the phenomena of the animal life, though
they possess their seat essentially in the organic life.
  When  very  strong,  the  very lively affection of the
internal organs produces so impetuously the sympathetic
motions of the muscles, that  the  action of the brain  is
absolutely null upon them; but the first impression past,
the ordinary  mode of locomotion returns.
  A man is informed by letter and in presence of com-
pany, of a piece of news,  w^hich it  is' his interest  to
conceal.  All on a sudden his brows become contracted,
he grows pale, and  his features are moulded according to
the nature of  the passion, which has been excited.  These
are sympathetic phenomena produced  by the abdominal
viscera  which  have been affected by the  passions, and
which in consequence belong to the organic life.  But in
a short time  the man  is  capable of  putting a  constraint
upon himself,  his  countenance clears  up, his  colour
returns.  Meanwhile the  interior sentiment continues to
subsist however, but the voluntary have overpowered the
sympathetic  motions,  the action of  the  brain has sur-
mounted that of the stomach or the liver; the  animal
life of the  man has resumed its empire.
   In almost all the passions the movements of the animal
life are mingled with those of the organic life, or succeed
to them ;  in  almost all the passions,  the muscular action
is in part  directed  by  the  brain, in part by the organic
viscera.  The  two  centres alternately overpowered the
one by the other, or remaining in a  state of equilibrium,
constitute  by the modifications of their inriuence, those
numerous varieties which  are seen in our mental affections.
   And not only on the brain, but on  all the other  parts
of the body  also do the viscera affected by the  passions
exercise their  sympathetic  influence.  Fear affects the 
ON LIFE AND DEATH.
69
stomach in the  first place, as  is  proved  by the sense of
stricture felt there at such time.*   But when thus affect-
ed, the organ re-acts upon the skin, with which it has so
strict a connexion, and the skin immediately becomes the
seat of the cold  and sudden sweat, which is then so often
felt.   This sweat is still however of the  same nature with
that which is occasioned by tea, or warm  liquids.  Thus
a glass of  cold water, or a  current of  cold air, will sup-
press  this  excretion by  means-  of the  relation, which
exists between the skin,, and the  mucous  surfaces of the
stomach  or bronchiae   We  must  carefully  distinguish
between  sympathetic sweating,  and  that, of which the
cause is directly made upon the skin.
   Hence though the brain  be not the  only term of the
re-action of the  internal, viscera which are affected  by
the passions, it is nevertheless the principal one, and in
this  respect may always  be  considered as a focus at all
times in opposition to that which is centered in the inter-
nal organs.

IV.  Of the epigastric centre.—It does not exist  in  the
          sense,  which Authors have pretended.

   Authors have never been at variance with  respect  to
the cerebral focus.   The  voluntary  motions  have ever
   * There is no proof that the sense of stricture which is felt in the
epigastric region, is  connected with the stomach ; and if it were proved
that it was so, it would not follow from it that this organ was primarily
affected from fear.   The same passion  sometimes acts differently in
different individuals; there are some who do not feel this stricture in
the epigastric region, but who are deprived of the use of their legs ;
must  it be  said that in  these  individuals  the seat of fear is in the
extensor muscles of the legs ?  If the introduction of a warm drink
into the stomach produces an increase of cutaneous exhalation, should
we conclude from analogy, that it is by acting primarily upon this organ
that fear causes that cold sweat which sometimes accompanies it ? 
71             PHYSIOLOGICAL RESEARCHES
been regarded  as an effect of its irradiations.   They do
not  equally agree upon the subject of the epigastric focus;
some of them  place  it  in the  diaphragm, others in  the
pylorus, others  in  the plexus  of the  great  sympathetic
nerve.*
  *Note by the Author.—This nervous network, going principally from
the semi-lunar ganglion, belongs to almost the whole abdominal  vascu-
lar system, whose  various ramifications it follows.  It is, according to
the usual  manner of considering it,  one of the divisions of the great
sympathetic; but it seems to me that the ideas of anatomists respecting
this important nerve  are not conformable to nature.
  Every one considers it as a medullary cord, extending from the head
to the sacrum, sending in its course various  ramifications to the neck,
the thorax and  the  abdomen,  following in  its  distributions a  course
analogous to those nerves of the spine, and deriving its origin from those
nerves, according  to some, and from those of the  brain, according to
others.  Whatever, be the name by which it is designated, sympathetic,
intercostal, &c; the manner of describing it is always the same.
  I believe that this  manner is altogether wrong, that there really exists
no nerve  analogous to the one designated  by  these words, and  that
what is taken for  a  nerve is only a series of communications between
different nervous centres, placed at different distances from each other.
  These nervous centres are the  ganglions, scattered  throughout the
different  regions, they have all an independent and insulated action.
Each is a particular centre  which sends in various directions many
ramifications,  which  carry to their  respective  organs  the irradiations of
the centre from which they go off.  Among these ramifications, some
go from one  ganglion to another;  and as these branches which unite
the ganglions form by their union a kind of continuous cord, this has
been considered as a distinct nerve; but these branches are  only com-
munications, simple anastomoses,  and not  a nerve  analogous  to the
others.
   This is so true, that these communications  are  often  interrupted.
There are subjects, for example,  in  whom is  found a  very distinct
interval between the pectoral and lumbar portions of what is  called the
great sympathetic, which seems to  be cut off in this place.  I have seen
this  pretended nerve cease and afterwards reappear, either in the lumbar
or sacral region.  Who does not know that sometimes a single branchy
sometimes many go from one ganglion to another, especially between
the  last  cervical  and the first  dorsal; that thesize of  these branches 
ON LIFE AND DEATH.
71
   But on this point, they  appear to me to be  all of them
in  the  wrong.   They  assimilate  or rather identify  the.
second with the first focus—they think, that the passions,
as well as the sensations  have their seat in an invariable

varies remarkably; and that after having furnished many divisions, the
sympathetic is larger than before it gave off any ?
  These considerations evidently prove that the communicating branches
of the ganglions no more suppose a continuous nerve than the branches
which go from each of the cervical, lumbar or  sacral  pair to the two
pair which are superior and inferior to them.  In fact, notwithstanding
these communications, we consider each pair in  a separate manner, and
do not regard their union  as a nerve.
  It is necessary to describe in the same way separately  each ganglion,
and the branches which go off from it.
  Hence I shall  divide hereafter in  my descriptions,  in which I have
hitherto pursued the ordinary course, the nerves into two great systems,
one arising from the brain, and the other from the ganglions; the first
has a single centre, the second has a great number of them.
  I shall first examine the  divisions of the cerebral system ; I shall
afterwards treat of the system of the ganglions, which   may be subdi-
vided into those of the  head, the neck, the thorax, the  abdomen and
the pelvis.
  In the head is found the lenticular ganglion, that of Meckel, that of
the sublingual  gland, &c. &c.   Though  no communication connects
these  different  centres,  either together or with  the pretended  great
sympathetic, yet their description belongs to that of the nerves of which
this is the connecting link,  as the communications  are arrangements
merely accidental to this system of nerves.
  In the neck there are the three cervical ganglions, sometimes another
upon the side of the trachea, in  the  thorax the  twelve thoracic, in the
abdomen the  semi-lunar, the lumbar, &c.  and in the pelvis the sacral;
these  are the  different centres  whose ramifications it is necessary to
examine separately, as we do those of the cerebral centre.
  For example, I shall first describe the semi-lunar ganglion, as we do
the brain; then I shall examine the branches, among which, is that by
which it communicates with the  thoracic ganglions, that is to say, the
great  splanchnic ; for it is very incorrect to consider  this nerve as
giving origin  to the ganglion.  In the same way, in the neck and the
head, each ganglion  will be first described ; then I shall treat  of its
branches, among which  are those of communications.  The arrange- 
72
PHYSIOLOGICAL  RESEARCHES
centre.   That, which has led  them  to  this opinion has
been  the sentiment of  oppression, which  is felt  at the
cardia under all painful affection.
   But it is to  be remarked,  that in the  internal  organs,
the  sentiment produced  by the affection of a part is always
an unfaithful index of the seat and extent of such affection.

ment being nearly the same for the  ganglions of the  thorax, the pelvis
and the loins, the description  of each region will be similar. .
  This manner of describing  the nerves, by placing  an evident line of
demarcation between the two systems, exhibits these two systems such
as they really are in nature.
  What anatomist, in fact, has not been struck with the differences
that  exist  between the nerves  of  these  two systems ?  Those of the
brain are larger, less numerous, whiter,  more compact in their texture
and exhibit less variety.  On  the contrary, the extreme tenuity, great
number, especially  towards  the plexuses, greyish  colour, remarkable
softness of texture  and varieties extremely common are characters of
the nerves coming from the ganglions, if we except those of communi-
cation with the cerebral nerves and some of those which unite together
these small nervous centres.
  Besides, this division of the  general system of the  nerves  into two
secondary  ones, accords veTy  well with  that of life*.  We know in fact
that  the external functions, the  sensations, locomotion and the voice
are all dependent on the cerebral nervous system; that on the contrary,
most of the organs which  perform  the internal functions derive from
the ganglions their  nerves, and with them the principle of their action.
We know  that animal sensibility and  contractility arise from the first,
and that where the  second alone are found, there is'only organic sensi-
bility and contractility.
  I have said that  the termination  of this  kind of  sensibility and the
origin of the corresponding contractility are in the organ in which they
are  noticed ;  but  perhaps both the termination  and origin  are  more
remote, and are in the ganglion from which the organ receives its nerves,
as the termination of animal sensibility and the origin  of the contractility
of the same species are always in the brain.  If it be  so, as the ganglions
are very numerous, we can understand why the forces of organic life
do not refer, like those of  animal life, to a common  centre.
  It is evident from these considerations, that there is no great sympa-
thetic nerve, and that what has been designated by this word is only an 
ON LIFE AND DEATH.
73
For example, hunger must undoubtedly affect the whole
of the stomach, but the sensation of hunger is transmitted
to us only  by  the cardia.   A large inflamed surface in
the pleura for the  most part gives rise to a pain, which is
felt only in a point.  How often  does it happen that in
the head or the  abdomen a pain which is  referred but to
a very limited space coincides with a largely disseminated
affection, with an affection possessing even a different seat
from that which is presumed.   We should never consider
the place to which we refer the sentiment as a sure index
of that which the affection occupies, but only  as a  sign
that it exists either there or thereabouts.
   From all this it follows, that to form a judgment of the
organ, to which such or such a passion relates,  we ought
to recur to  the effect  produced in the  functions of the
organ by the influence  of the passion, and not to the  feel-
ings of the patient.  In setting out  from this principle it
will  be easy  to see,  that  it  is sometimes the stomach
and alimentary canal, sometimes the sanguiferous system,
sometimes  the viscera belonging to the secretions which
experience a  change.

assemblage of small nervous systems, with distinct  functions, but with
communicating branches.
  We see then  what  should be thought of  the disputes of anatomists
respecting the origin of this pretended nerve, placed in the fifth, sixth
pair, &c. in those of the neck, back, &c.
  Many physiologists  have entertained concerning the ganglions  opin-
ions similar to those which  1 have now offered, by considering  these
bodies  as small  brains; but it is essential that these opinions should
enter into the description, which, as it is now made, gives a very inac-
curate idea both of these nervous centres and of the nerves which go
off from them.
  The expression of nervous branches giving origin to such or such a
ganglion, &c. resembles that in which we should consider the brain as
arising from the nerves of which it is itself the origin,
               10 
74
PHYSIOLOGICAL RESEARCHES
   I shall not repeat the proofs of this assertion, but sup-
 posing it to be demonstrated, I shall assert that there does
 not exist for the passions as there does for the sensations
 a  fixed  and constant centre ; that  on the contrary the
 liver,  the lungs, the spleen, the stomach,  and the heart,
 are  turn by turn affected, and  at  such  time  form that
 epigastric centre so celebrated in modern works; and if
 in general we refer to this region  the sensible impression
 of all  our affections, the  reason is that all the important
 viscera of the organic life, are there concentrated.  In
 fact, if nature had separated these viscera, had the  liver
 for instance been placed in the pelvis,  and  the stomach in
 the neck, the  heart  and  spleen  remaining as they  now
 are seated, in  such case the epigastric  focus would disap-
 pear, and the local sentiment of our passions vary accord-
 ing to  the part affected.
  In  determining the  facial  angle, Camper  has  thrown
 much  light upon the  proportion  of intelligence enjoyed
 by  the several classes of animals.  It appears  that not
 only the functions of the  brain, but that all  those of the
 animal life which are  centred  there, have  this  angle for
 the measure of their perfection.
  It would be a very pleasing thing could  we indicate in
 the same way  a measure, which assumed from the organs
 of the  internal life,  might fix the rank of each  species
 with regard  to the passions.  The dog  is  much more
 susceptible than other animals of  the sentiments of grati-
 tude, of joy, of sorrow, of hatred, and of friendship ; has
he any thing more perfect in his organic life? the monkey
 astonishes us by his industry, his disposition to imitate,
 and by his intelligence ; his animal life is certainly supe-
rior to that of every other species.  Other animals, such
 as the elephant, interest  us  by  their attachment,  their
 affection, their passions ; they delight  us also with  their 
ON LIFE AND DEATH.
715
address, and the extent of their intelligence.   With them
the cerebral centre  and the organic viscera  are  perfect
alike.
  A rapid glance over the series of animals will show us
also, that in  some of them the phenomena, which  arise
from sensation  predominate over those which have  their
origin in the passions ; in others we shall see the latter
superior in power to the former, and in others again, a
balance  established  between  the  two.   These circum-
stances,  which  we remark in the long chain of animated
beings, we may remark in the human species when con-
sidered  individually  In one man the  passions are the
great principle of motion ; the  influence of his animal
life is continually surpassed by that of his  organic life,
and incessantly induces him to act in a way to which the
will is almost a  stranger, and which  often  entails  upon
him the bitterest  regret, when his animal life resumes its
empire.  In  another man,  the animal life is the stronger
of the two.  In  such case, the  understanding seems to
be  augmented at  the expense of the passions, the latter
remaining  in that silence, to which the organization of
the individual  has condemned them.
  That  man enjoys the happiest  constitution  in whom
the two  lives are balanced, in  whom  the  cerebral and
epigastric centres exercise  the  one upon  the other an
equal action, whose  intellect is warmed,  exalted, and
animated by the passions,  but  whose  judgment makes
him at all times master of their influence.
  It is this  influence of the  passions  over the  actions of
the  animal  life,  which  composes what is  named the
character.  Character as well as Temperament depends
upon the organic  life ; possesses all its attributes, and is a
stranger to the will in all its emanations; for our exterior
actions  form a picture of which the ground and design 
76
PHYSIOLOGICAL RESEARCHES
do indeed belong to the animal life, but upon which the
organic life extends the shading and colouring of the pas-
sions.  The character of the individual is constituted by
such shades and colours.
  The alternate predominance of the two  lives has been
remarked  by  almost all philosophers.   Plato,  Marcus
Aurelius,  Bacon, St. Augustine, St. Paul,  Leibnitz, Van
Helmont,  Buffon  and many others, have  recognized in
man two  principles, by one of which  we  become  the
masters of all  our moral actions, by the other the  con-
trary.  We have nothing to do with the nature of these
principles.  Our business is with their  phenomena ; wre
shall analyze the relations by which they are united.
                  CHAPTER VII.

GENERAL DIFFERENCES OF THE TWO LIVES WITH RESPECT
                  TO VITAL POWER.

  The greater number of Physicians, who  have written
upon the vital properties, have begun  by researches on
their principle, have endeavoured to descend  from the
knowledge of the nature of this principle to that of its
phenomena, instead  of  ascending  from observation  to
theory.   The  Archaeus  of  Van  Helmont, the soul  of
Stahl, the vital principle of Barthez, the vital  power of
others, have each in  their  turn been  considered as the
sole  centre of every  action possessing the  character of
vitality, have each in their turn been made  the common
base of every physiological explanation.  But these bases
have every  one of them been  sapped, and  in the midst
of their  wrecks  have  remained  the  facts  alone which 
                ON LIFE AND DEATH.              77

rigorous  experiment has furnished upon  the  subject of
sensibility and motility.
  So narrow indeed  are the limits of the  human under-
standing, that  the  knowledge of first causes has almost
always been interdicted.   The veil, which  covers them
envelops with its innumerable folds whoever attempts to
rend it.
  In the study of nature,  principles  are certain general
results of first causes, from whence proceed  innumerable
secondary results.   The art of finding the connexion of
the first with the second is that of ever}' judicious mind.
To seek  the connexion of  first causes with  their general
effects is to  walk blindfold  in a road from whence a thou-
sand paths diverge.
  Of what  importance besides to  us  are  these  causes ?
Is it  necessary  to  know the nature of light, of oxygen
and caloric to  study  their  phenomena ?   Without the
knowledge of the principle of life, cannot we analyze its
properties ?   In the study of animals let us  proceed  as
modern  metaphysicians  have done in that  of the under-
standing.  Let us suppose causes, and attach ourselves  to
their general results.

  I. Difference  between vital power and physical law.

   In considering the powers of life, we shall  perceive in
the first place a remarkable difference between them and
the laws of physics.   The first  incessantly vary in their
intensity, in their energy, in  their development, are con-
tinually  passing from the last degree of prostration, to the
highest pitch of exaltation, and assume under the influence
 of the most trifling causes a thousand modifications; for
 the animal  is influenced by every thing which surrounds
 him ; he wakes, he sleeps, reposes or exercises himself, 
78          PHYSIOLOGICAL RESEARCHES
digests, or is hungry, is subject to his own  passions, and
to the action  of foreign bodies.   On the  contrary the
physical  laws  are invariable, the  same  at all times, and
the source of a series of phenomena at all times similar.
Attraction is a physical power; it is always in proportion
to the mass of brute matter in which it  is observed ;
sensibility is a vital power, but in the same mass of mat-
ter, in the same organic part its quantity is perpetually
changing.
  The invariability  of the laws which  preside  over the
phenomena of physics, enables us  to apply the formula
of calculation  to all  the  sciences, which have  them for
their object.  Applied  to the actions of the living body,
the mathematics can never give us formula. , The return
of a comet, the  resistance of a fluid in traversing an inert
canal, the rapidity of a projectile may be calculated; but
to calculate with Borelli the force of a muscle, with Keil
the velocity of the blood, with Jurine and  Lavoisier the
quantity  of air, which  enters  into the  lungs, is to  build
upon a quicksand, an edifice solid of itself, but necessarily
decreed to fall for want of  a foundation.
  This instability of the  vital powers, this disposition,
which they continually have  to change,  impress  upon
all  the physiological phenomena a character of irregu-
larity  which particularly  distinguishes  them from  those
of physics.   The latter forever the same, are well known
when once they have  been analyzed ;  but who can say
that he knows the former,  because he has analyzed them
under the   same circumstances,  a multitude of  times.
The urine indeed,  the saliva, or  the  bile indifferently
taken from such or such a subject,  may be  analyzed, and
hence results our animal chemistry; but such a chemistry
is the dead anatomy of the  fluids,  not a physiological
chemistry.  The physiology of the fluids should be com- 
ON LIFE  AND DEATH.
79
posed of the innumerable  variations which they experi-
ence according to the different states of their respective
organs.
  The urine after taking food is not the fluid, which it is
after sleeping; it contains in winter, principles which are
foreign to it, during summer, when  the  principal  excre-
tions  are made by the skin.  The simple passage from
heat to  cold,  in suppressing sweat, and the  pulmonary
exhalation,  will change its  composition.  The same is
true of the other fluids ; the state of the vital powers in
the organs, which  are the  sources  of them,  changes at
every moment; and therefore, the  secreted  substances,
wrhich entirely  depend upon the mode of action  in the
organs, must be as various.
  Who will venture to assert, that he  knows the  nature
of a fluid of the living economy if he has not analyzed it
in the infant, in the adult, and the aged, in the male and in
the female, at every season, during the calm of the mind,
and the storm of the passions, which so manifestly influ-
ence its nature ?  To know  such  fluid perfectly, will it
not be requisite also to  examine the different alterations
of which it is succeptible in  consequence of disease?
  The instability of the vital powers, is the quicksand on
which have sunk the calculations  of  all the Physicians of
the last hundred years.   The habitual variations of the
living  fluids,  dependent on  this  instability,  one  would
think should be no less an obstacle to the analyzes of the
chemical physicians of the present age.
  From this  reasoning it is easy to  perceive, that  the
science of organized bodies should be treated in a very
different manner from that of inorganic  bodies.   To the
former a different language  almost  is  requisite; for  the
greater number of the words, which we transfer  from the
physical sciences, into those of the  animal or vegetable 
80            PHYSIOLOGICAL RESEARCHES
economy, incessantly recall ideas, which are by no means
consistent with their phenomena.
  Had physiology been cultivated by men before physics,
I am persuaded  that  many applications of  the former
would have been made to the latter ;  rivers would have
been seen to flow  from the  tonic action of their  banks,
crystals to unite  from the excitement, which they exer-
cise upon their  reciprocal  sensibilities, and  planets  to
move because they mutually irritate  each  other at vast
distances.   All this would appear  unreasonable to us, who
think of gravitation only in the  consideration of these
phenomena ;  and why should we not in fact be as  ridicu-
lous when we come with this  same gravitation, with our
affinities and chemical compositions, and with a language
established  upon their fundamental  data  to  treat  of a
science,  with  which they  have  nothing whatsoever  to
do.  Physiology would have  made a  much greater pro-
gress, if all those who studied it, had set aside the notions
which are  borrowed  from the accessary sciences, as they
are termed.   But these sciences are not accessary;  they
are wholly strangers to physiology, and should be banish-
ed from it wholly.*

  * Bichat often  complains in  his  works of the  injury that has been
done to the physiological  sciences, by the attempts  that are made to
facilitate the study of them by  means of physics.  He was not compe-
tent to decide the question, not having sufficient data  in the sciences,
the use of which he reprobated; the most that he should have said, was
that a bad application had been made of them.  Even this reproach
was loo general to  be just.  No doubt, mankind have been led into
errors  by attempting to support on slight foundations a science which
was still in its infancy ; but even in the time of Bichat it could not be
denied that  it was to the progress of these same sciences, that was
owing the explanation of many very important  phenomena ; that by it
was ascertained what takes place in respiration, and by what means a
living  body always  supports itself between certain limits of tempera-
 ture, &c. 
ON LIFE  AND DEATH.
81
  Physics and chemistry are related to each other in many
points, because the same  laws in a variety of instances
preside over the phenomena of both of them ;  but an im-
mense interval divides them from the science of organic
bodies ; because a very great difference  exists  between
the laws which are proper to them, and those of life.   To
say that physiology is made up of the physics of animals,
is to give a very inaccurate idea of it; as well might we
say that astronomy is the physiology of  the stars.
  But the present digression has already been much  too
long.   We  shall  now  consider  the  vital powers with
respect to the two lives of the animal.


II.  Difference betioeen the vital properties and those
                      of texture.

  In  examining the properties of every  living organ, we
may  distinguish  them  into  two  kinds.  Those of  one
kind  are  dependent  immediately  upon  life, begin  and
finish with it, or rather  form its principle and its essence.
Those of the other are connected with it only indirectly,
and appear  rather  to depend upon the  organization  and
texture of the parts of  the body.
  The faculties of perceiving and spontaneously contract-
ing are vital properties  : extensibility, and the faculty of
contraction  upon  the cessation of the extending power,
are properties of  texture ;  the  latter it  is true,  are pos-
sessed of a greater energy  when existing  in the living
fibre, but they remain with the organ when life  has ceas-
ed ; the decomposition  of the organs, is  the term of their
existence.   I  shall first examine  the vital properties.
              11 
O-i
PHYSIOLOGICAL RESEARCHES
 III.  Of the  two  kinds  of sensibility ; of the animal
                and organic sensibilities.

   It is  easy  to  perceive, that the vital  properties  can be
 only those of perception  and motion, but in the two lives
 they possess  a very  different character.  In the organic
 life, sensibility is  the faculty of receiving an impression;
 in the animal life, it is  the faculty of receiving an impres-
 sion and moreover of referring such impression  to a com-
 mon centre.*  The stomach is  sensible to  the presence
 of aliments, the heart  to the stimulus of the blood,  the
 excreting  tube to the contact of the fluid, which is pecu-
 liar  to it;  but the term of this sensibility is  in the organ
 itself.  In the same way do the  eyes, the  membranes of
 the  nose and the  mouth, the skin,  and all the mucous
 surfaces, at their origin, receive an  impression  from  the
 bodies  which are in contact with  them, but they after-
 wards transmit such impression to the brain, which is  the
 general centre of the sensibility of these organs.
  There is an  animal  sensibility  then, and an organic
 sensibility.   Upon  the one depend  the phenomena  of
 digestion,  circulation,  secretion, exhalation, absorption,

  * It must be remembered  that the existence of such a sensibility is
 purely conjectural.  As it is  uot transmitted to a common centre, we
 can recognize it only by its effects. In order to explain these effects,
 there is no need  of admitting a similar faculty.  This sensibility more-
 over, if its existence should  be admitted, would  be found  continually
 in fault.   The stomach, for  example, allows a substance to go out of
its cavity which  could  never serve  for aliment, provided this substance
exhibits a degree of fluidity approaching that of chyme.   The absorbents
take  up  the  most  noxious fluids,  those even the action of which is
sufficiently powerful to destroy the organization of their parietes ; the
heart contracts without the entrance of the blood into it, &c. 
ON LIFE AND  DEATH.
83
and  nutrition.  It is common to the plant, and the animal;
the Zoophyte enjoys it as perfectly as the most  perfectly
organized quadruped.   On the other depend sensation and
perception, as well as the pain  and pleasure which  modify
them.  The  perfection of  animals, if I  may so speak, is
in proportion to the quantity of this sensibility,  which
has  been bestowed upon  them.   This  species of sensi-
bility is not the attribute of vegetable life.
   The  difference of these two  kinds of sensitive power is
particularly well marked in the manner of their termina-
tion, in the  case of violent and  sudden  death.  In such
case, the animal sensibility is at once extinguished; there
can  no longer  be  found any trace of it at the moment
which succeeds to  strong concussion of the brain, to great
haemorrhage or  asphyxia; but  the  organic  sensibility
survives  such  accidents more or less.   The lymphatics
continue to absorb, the muscle is still sensible to stimuli,
the  nails and the  hair continue  to be nourished, and in
consequence are sensible of the fluids which they imbibe.*


  * This is altogether  inaccurate; a nail  in growing is not nourished,
any more than the mucus is nourished in the nasal fossae, or the urine
in the bladder. The nails, the  hair  on  the various parts of  the body
and the hair of the head, all in a word epidermoid productions, are the
result of real secretions which do not  differ from the secretions of which
we have just spoken, only in this, that the product instead of remaining
fluid  like the urine, or viscid like the mucus, hardens as it comes out
of the secretory organ, like the thread of the silk worm, or that of the
spider.  A certain number of these  organs is commonly  arranged in
such a mauner, that the matter secreted  by each of them is found in a
fluid  state in contact with that of the neighbouring organs, with which
it is agglomerated  in hardening.  Arranged in concentric circles around
a small cone, they produce a hollow cylinder ; extended in parallel  lines
upon a broad surface, they  produce  a flattened  lamina.   Such is the
manner in  which the nails and the hair are formed.  We see from this
that  the epidermoid productions grow,  but  are not nourished.   The
hair  exhibits, it is  true, an internal cavity, filled with a coloured fluid, 
84
PHYSIOLOGICAL RESEARCHES
It is often a  considerable time before  all traces of this
sensibility are effaced ;  the  annihilation of the  other is
instantaneous.
   Though at  the first glance, the two sensibilities present
us so remarkable a difference, their  nature  nevertheless
appears to be essentially the same.  The one  perhaps is
only the maximum  of the other,  is the same force,  but
according to ils intensity is shown under different charac-
ters.  Of this the following observations are proofs.
   There are different parts in the  economy, where  these
faculties are concatenated, and  succeed  each other insen-
sibly.   The  origin  of  all the mucous membranes  is an
example of such parts.   We  have the sensation of  the
passage of aliments in the mouth, and the back part  of it;
this  sensation becomes  weaker at the  beginning of  the
oesophagus, decreases still towards its middle,  and disap-
pears at its end, as well  as  in  the stomach,  where  the
organic sensibility only remains.  The same phenomena
may be observed in the urethra, &c.   In the neighbour-
hood of the skin, the animal sensibility exists; it gradually
diminishes, however, and becomes organic in the interior
of the system.
   Divers excitants applied to the  same organ  may  alter-
nately produce the one, and  the other mode of sensibility.
When irritated  by acids,  by very concentrated  alkalies,
or by a  cutting instrument, the  ligaments do not  transmit
to the  brain  the very strong impression  which  is  made
upon  them, but if they be twisted, distended  or rent, a

which appears to be necessary for  its preservation ; but we  can easily
conceive  how an oily fluid may help to preserve it, by giving it supple-
ness and  thus preventing it from breaking.  This fluid is poured  into
the canal in which it is found, and it is not the hair which draws it in, any
more at least, than a capillary tube draws in  the fluid into which its
extremity is plunged. 
ON LIFE  AND DEATH.
85
lively sensation of pain is the result.*   I have established
this fact  by a  number of experiments in my treatise on
the  membranes!   The following is  another of the  same
kind, which  I  have since observed.  The  parietes of the
arteries as we  know are  sensible to the blood by which
they are  traversed, but at the  same time  are the  term of
this sentiment.  If a fluid, however, which is foreign to
this system,  be injected into it,  the animal will  immedi-
ately discover  by  his cries,  that he  is  sensible of the
presence  of such  fluid.t
   We have seen that it is a property of habit, to  weaken
the sentiment, to transform into  indifferent sensations all
those of pleasure, or of pain.  Foreign bodies, for example,
will make upon the mucous membranes a painful  impres-
sion during the first days of their application  to it ;  they
develop in such parts  the animal sensibility, but  by little
and little this sensibility  decreases, and the organic  alone
subsists.   In this way the urethra is sensible of the bougie

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

  tSo, as long as the fluid is retained in the artery, which is easily done
by means of ligatures, no pain is  manifested ; but when the  irritating
substance is carried by the vessels to the heart or to  any other sensible
part, we can easily conceive that the animal must experience pain, for
the irritant always produces its effect, whether it be carried directly to
the part or arrive there by means of  the circulation. 
86
PHYSIOLOGICAL RESEARCHES
as long as it continues there, for during the whole of such
time, the action of the mucous glands of the passage is
augmented, from whence arises a species of catarrh, but
the individual for the first  moments only had  a painful
consciousness of the presence of the instrument.
   We every day observe, that inflammation  in  exalting
the organic sensibility of a part, transforms the organic
into the animal  sensibility :  the cartilages thus, and the
serous membranes which in their ordinary state have only
the obscure sentiment, which is necessary to  their nutri-
tion, in an inflammatory state are possessed of an animal
sensibility, which  is  frequently stronger  than that of
the organs to which it is natural.  And why ?  Because
the essence of inflammation consists in accumulating the
powers of the part,  and this  accumulation suffices  for
changing the  mode  of  the organic  sensibility, which
differs from the animal sensibility in quantity  only.
   From these considerations it is evident that  the distinc-
tion above established  with respect to  sensibility consists
in the  different modifications of which this power is sus-
ceptible, and  not in its nature, which is every where the
same.   This  faculty is common to  all  the organs ; they
are all of them possessed of it; it forms their true vital
character ; but more  or  less abundantly  distributed to
each, it gives to each  a different mode  of existence.   No
two parts enjoy  it in  the  same proportion.    In  these
varieties there is a degree, above which the brain  is the
term of it, beneath  which the  organ alone  is sensible of
the impression.
   If to render my ideas on this head more clear I were to
use a vulgar expression, I should say that  distributed in
such a dose  to an organ, sensibility is  animal :  in such 
ON LIFE AND DEATH.
87
 another dose, organic*—Now that, which varies the dose
 of sensibility, is sometimes the order of nature, (in which
 way the skin and the nerves are more sensible than the
 tendons, and cartilages;)  at other times, disease ; thus in
 doubling the dose of sensibility to the cartilages inflamma-
 tion renders them equal in this respect, and even superior
 to the  former,  and as  a  thousand causes may  at  every
 moment exalt or diminish this  power in any part of the
 body it may be changed at every moment from the animal
 to the  organic type.   Hence the reason, why authors,
 who have made it the object of their  experiments, have
 come to results so different; and why some of them have
 observed the periosteum and dura mater to be insensible,
 while  others have put them down  on  the  contrary as
 endowed with an extreme sensibility.

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

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

  •These expressions dose, sum, quantity of sensibility are incorrect,
inasmuch as they exhibit this  vital faculty under the same point of view
as the physical forces, as attraction, for example ; and as they present
it to us as susceptible of calculation, &c.; but, from a  want of words
for one science, it is necessary, in  order to make it  understood, to
borrow them from the other sciences.  There are expressions, like the
words to solder, to glue, to unglue, &c. that are used for the  want of
others in the osseous system, and which really give very  inaccurate
ideas, unless the mind corrects the sense. 
S8
PHYSIOLOGICAL RESEARCHES
   It  is this determined  sum of sensibility,  which espe-
cially composes the  life of each organ, and fixes the nature
of  its relations with  foreign bodies ;  in  this way  the
ordinary  sum of sensibility in the  urethra fits  it for  the
passage of the urine, but if this  sum be augmented, as in
strong erection of the penis, the above relation  ceases :
the canal refuses passage to the urine, and suffers  itself to
be traversed  by the semen only, which in its turn has no
relation with the sensibility of the urethra when the penis
is not erected.*
   From  hence  proceeds the reason of the puckering up
and spasm of the parotid, the cystic, and pancreatic ducts,
as well as of the  excreting tubes  in  general, when  the
molecules of any  other fluid than  that, which they are
destined  to  convey are presented to them.   The  sum
of their sensibility corresponds exactly with  the nature of
their respective fluids, but  is disproportioned to  that  of
any other.t—The spasmodic  contraction of .the larynx

  * If the  urine, during a  perfect erection,  does  not go out of the
bladder, it is because  the contraction of the muscles of the perineum,
and especially  of the levator ani, prevents it.  If these  muscles are
relaxed, though the turgescence of the  corpus cavernosum and of the
urethra remains the same, the urine flows out without any other obstacle
than what  arises from the  contraction of the  canal produced by the
swelling of its parietes.
  t These  different excretory ducts do not exhibit in the  mammalia
any contractility.  There is no stimulus which  can produce it in them ;
I have tried them all  in vain.  In birds, on the contrary, the ureters
and the pancreatic and biliary canals are contractile, and their motions,
which return at intervals, are too well marked to be mistaken.  It
appears that the contractility of the excretory canals in the  abdomen,
is connected in  these  animals with the absence  of the diaphragm.  We
know in fact that this muscle in the mammalia, assists  by  the pressure
which it exerts, the course of  the secreted  fluids, and  renders useless
the existence of a peculiar  motion in the canals which contain them.
If it be however pretended that this motion exists in them, but that  it 
ON LIFE AND DEATH.
89
when  irritated  by any foreign body is produced in the
same manner;  for the same reason the  ducts, which open
upon the mucous surfaces, though at all times in contact
with a variety of different fluids,  are never penetrated by
them.*   The mouths  of the  lacteals,  however  patulous
within the alimentary  canal, will take up the chyle only,
they reject the  fluids, which are mixed with it;  for with
these their sensibility has no relation.
   Such  relations do  not exist  only between the  different
sensibility of the organs, and  the different fluids  of the
body ;  but they may be exercised also between  exterior
substances,  and the various  parts of the  living system.
The sum of sensibility  in  the bladder, the kidneys and
the  salivary  glands  has a peculiar  analogy with cantha-
rides and mercury.  It might be  thought  that the sensi-
bility of each organ  is modified, that it assumes a peculiar

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

   * It is  not surprising, that  a  canal usually filled with the  excreted
fluids should refuse to admit another which runs in an opposite direc-
tion.
                12 
90
PHYSIOLOGICAL RESEARCHES
nature, and that  it is this diversity  of nature,  which
constitutes  the difference of the relations of the  organs
with  regard to bodies in contact with  them ;  but a num-
ber of considerations  tend to  prove  that  such difference
is occasioned,  not by  any difference  in the nature, but in
that of the  sum, the dose, the quantity of the sensibility,
if such words  may be  applied  to a  living property..  I
shall  adduce the following instances :—
   The absorbent orifices of the serous surfaces, are some-
times bathed for months together in the fluid  of dropsies,
and take  up  nothing.   But  if  the  sensibility  of these
orifices be  exalted  by  tonics, or  an effort of nature, in
such, case it will place  itself, if I may so say, in equili-
brium with the fluid,  and absorption will be made.  The
resolution  of  tumours  presents us  with the same  phe-
nomena;  as long as the powers of the parts are weakened*,
the lymphatics refuse admittance to the extravasated sub-
stances; but if the sum  of these powers be augmented by
the use of  resolvents, in a short  time, from the  action of
,the lymphatics, the tumour will disappear : from  the same
cause the blood, and other fluids are taken up with a sort
of avidity  at times, and at others, not  at all.*

   * All that is here said.of the sensibility of the lymphatic vessels, which
makes them sometimes admit and sometimes  reject the effused fluids, is
the more hypothetical, as it is not as yet proved that these vessels are
the agents  of absorption.  It should  be remarked, that the fluids that
are supposed  to be absorbed by them, differ essentially in their chemical
composition,  from the fluid that is usually found in their cavity.  This
fluid besides varies  but very little in its composition, though its appear-
ance  is not  uniformly the same; now, if it were the result of the
absorption  of fluids differing  from each other, its  composition ought
also to vary as that of the chyle does, according to the nature of the
aliments.
   Before the lymphatic vessels were known, the principal  phenomena
 of absorption were observed, and it was  natural to attribute them to
 the action  of the vein9.  This opinion was maintained for a long time 
ON LIFE AND DEATH.
91
   The art of the physician, then, in the use of resolvents,
must  consist in  ascertaining  the  degree of sensibility

after the  discovery of the  lymphatics.  Finally, towards the middle of
the last century, Hunter being engaged  in examining these vessels,
which he has done more to make known than any other man, thought
that they should be  considered as the agents  of absorption, and  this
opinion was  soon  generally admitted.  If we  look  for the means by
which he overthrew the ancient theory, we are astonished to find that it
was by five experiments only.  Harvey did not with equal facility obtain
the acknowledgment of the circulation, and  perhaps there  does  not
exist a second example of an  opinion, which was  for a long time
established, being abandoned so readily.   It should  be remarked, that
physiologists iiad not yet recovered from the surprise produced by the
discovery of a system of vessels so extensive, and  yet for so long a
time unknown ; they were impatient to  know the use of them ; the
veins had already the  function of returning  to the heart the blood
brought by the arteries; they thought it  would not impoverish them
too much to deprive them of the faculty of absorbing, in order to enrich
the lymphatics with it.   Of the five experiments of Hunter, two are
designed to prove that the veins do not absorb, the  object of the other
three is to show that the lymphatics do.
  In the first experiment he injected tepid water into a portion of intes-
tine, and the  blood which returned by the vein appeared to be neither
more diluted  nor lighter than before.  We  cannot conceive how by
mere inspection, it is possible to judsre if the blood contains a certain
quantity of absorbed water, a quantity which  must be proportionably
very small,  if we   consider the whole  amount of blood  that  passes
through the mesentric veins during the period necessary for the absorp-
tion of the fluid. Hunter in the same experiment tied the artery which
went to the portion  of intestine, and  examined the state  of the vein.
It did not swell, and its blood did not become aqueous.  But after this
ligature, did the absorption continue to go on in this portion of intestine,
which still  had no doubt lymphatic vessels ?  This the author does not
pay. How moreover should he think that the vein  could  continue its
action when the artery was tied ?
  In the second experiment Hunter injected  milk into a portion of
intestine, arid  was  unable  to discover this fluid in the blood of the
mesentric veins; but at the period  in  which this experiment was made,
mankind were very  far from being able to detect in the blood a very-
small quantity of milk, and at the present day, with all the aid derived 
92
PHYSIOLOGICAL RESEARCHES
 wrhich  he requires in  the vessels  for the  purpose which
 he has  in view; and in exalting or depressing this power

 from chemistry, we can hardly discover in it a small quantity which is
 mixed directly with it.  These two  experiments prove then nothing
 against the absorption of the veins ; as to those which he brings forward
 in favour of absorption by the  lymphatics, they are not more conclu-
 sive.   I  shall content  myself with relating one of them.  He injected,
 into a  portion of intestine that was empty, a certain quantity of warm
 milk, and confined it there by two ligatures.  The  veins that came
 from this portion were emptied of their blood by several punctures
 made in  their trunk.  The corresponding  arteries were tied.  He then
 returned the parts into the abdomen, and drew them out again in  half
 an hour.   Having examined them with  attention, he observed that the
 veins were almost empty, and that they contained no white fluid, whilst
 the lacteals were  almost  full of it.  But  was not this white  fluid  that
 filled  them chyle  rather than  milk ?  Was it  not there  before  the
 injection of this liquid ?  In order to ascertain what takes place  in the
 lymphatic vessels  during  absorption, we must begin by examining the
 state of these vessels before the experiment.  But this is what Hunter
 did not do, and it is this that renders his experiment of no value.   It is
 not very astonishing that he mistook the chyle for the milk, since milk
 has for a long time been  mistaken  for chyle.  Flandrin, Professor of
 the Veterinary School  at Alfort, has several times repeated  this experi-
 ment of  Hunter;  but  he took care before the injection of the milk to
 ascertain that the lymphatics contained no white fluid ;  and  he never
 found any in their cavity after the experiment.  I  have myself many
 times performed this experiment, with the same precaution, and I have
 uniformly obtained the same results as those of Flandrin.
  It would occupy too much time to examine all the reasons that have
 been advanced for and against the absorption of the  lymphatics; I shall
 only relate some experiments I have made myself;  but I ought first to
 observe,  that absorption undoubtedly takes place in parts  such  as the
 eye, the  brain, and  the placenta in which the most minute dissection
 has been  unable to discover any lymphatic vessel.
  First experiment.—Four  ounces of the decoction  of rhubarb  was
 given to a dog, in half  an hour after he was killed, and it was found that
more than half of the liquid had disappeared ; the urine evidently contain-
 ed rhubarb, but the lymph in the thoracic  duct exhibited no trace of it.
  Second experiment.—A  dog  swallowed  several  ounces  of alcohol
diluted with water; at the end of a quarter of an  hour, the  blood of 
ON LIFE AND DEATH.
93
accordingly.    In  this way, in  different  circumstances,
resolvents may be taken from the  class of the debilitating
or stimulating remedies.


the animal had a very distinct odour of alcohol, but there was nothing
of the kind in the lymph.
  Flandrin  made a similar experiment  on a horse, to whom he gave
half a pound of assafetida mixed with an equal quantity  of honey.
Six hours after, the horse was killed.  The odour  of the assafetida was
very perceptible  in the blood of the veins  of the stomach, of the  small
intestines and the  ccecum;  but it  could not be perceived in the
lymph.
  Third experiment.—A dog was made  to swallow  six ounces  of a
solution of Prussiate of Potash in water.  In a quarter of an hour, the
urine  very evidently contained some of the Prussiate ; but the  lymph
taken from the thoracic duct showed no appearance of it.
  Fourth experiment.—I gave to a dog, in whom I had tied the thoracic
duct, two ounces of a decoction of nux vomica.  The effects of absorp-
tion were as rapid as if the duct had been open.  After the death of the
animal I satisfied  myself, that the duct had been well tied, and that
there  was no  other branch, as there sometimes is, by which the  lymph
could get to the subclavian vein.
  I have varied this experiment by putting the poisonous fluid, into the
rectum, the sacs  of the pleura and peritoreum.  The results  have been
uniformly the same.
  Fifth experiment.—M. Delille and  myself made an incision into the
abdominal parietes of a dog, who had been  fed very heartily some hours
before, so that the lacteals  might be easily seen, and we then drew out
a portion of the  small intestine upon which we applied two ligatures
three  inches  from each  other.  The  lymphatics  that  went from this
portion of intestine  were full of chyle and very  distinct.   They were
all tied and  cut.   The blood vessels  were also tied and cut, with the
exception of  an  artery and a vein ; the  portion  of intestine also was
cut off beyond the  ligatures, and thus it  had no  communication with
the rest of the animal except by the vein and  artery which were left.
These two  vessels  were dissected with  the greatest care, and even
stripped of their cellular  coat, lest there might  be some  lymphatics
concealed in it; we then injected into the cavity of this  portion  of
intestine a decoction of nux vomica, and we retained it there by means
of a new ligature.  This portion of intestine, covered with  fine linen, 
94            PHYSIOLOGICAL RESEARCHES
   The whole of the theory of inflammation is  connected
with the above ideas.   It is well known that the system

was restored to the abdomen ; six minutes after, the effects of the poison
were manifested with their usual intensity.
  Sixth experiment.—M. Delille and myself separated the thigh of a
dog from his body, leaving only the crural artery and vein, which  kept
up the communication between the two parts.   These two vessels were
dissected with care, insulated to an extent of from two to three inches,
and even stripped of their cellular coat, for fear it might conceal some
small lymphatic vessel.  Two grains of a very active poison (the upas)
were then inserted into the  paw, and the effects were as sudden and as
intense as  if the thigh  had not been separated  from the body.
  As  it might be objected, that notwithstanding all the precautions
taken, the parietes of the artery  or  vein  might still contain some
lymphatic, we varied our experiment so as to leave  no doubt on this
point.  The artery was cut  entirely off, the communication was reestab-
lished between  the two ends, by means of a  leaden  tube introduced
into their cavity, and fixed  by proper ligatures.  The  same was  done
for the vein.  Thus there was no longer any communication between
the thigh and the  rest of the body, except by  the arterial  blood which
came  to  the thigh, and by  the  venous blood  which returned to the
trunk: the poison afterwards introduced into  the  paw produced its
effects in the ordinary time, that is in about four minutes.
  From  these different experiments, it is right to conclude  that  the
miDute branches  of the veins possess the power of absorbing ; that
they exert it on the surface of the mucous and serous membranes, and
in the interior of the  organs ;  that the experiments  that have  been
quoted in  favour of the absorption of the lymphatics are inaccurate or
incorrectly understood,  and finally that there is no  proof that these
vessels absorb any thing but chyle.
  Is it now necessary to refer to the venous branches this sensibility that
has been attributed to the ultimate ramifications of the lymphatics ?   But
this sensibility, as we have already said, would  be constantly in error;
the absorbent vessel does not select one fluid in preference to another;
all are indiscriminately  absorbed, even  the most irritating,  those in  fact
whose action is sufficiently powerful to destroy the vascular parietes.
Besides, the phenomenon then continues, when it is no longer possible
to suppose the  existence of this sensibility.    After death even, the
venous branches absorb still as they do during life, if they are  placed in
analogous circumstances; and to do this it is evident, that  an internal 
ON LIFE AND DEATH.
9o
of  the canals, which  circulate the blood gives birth to a
number  of  other small  vessels,  which  admit  only  the

current must be established, which resembles the course of the blood.
I shall  now  relate  an experiment, which I made on this subject, and
which  I selected from many others, because it appeared to me  to be
very conclusive.
  I took the heart  of a dog that had died the day before; I injected
into one of the coronary arteries some water of the temperature of 30
degrees of the  centigrade thermometer.   This water returned easily by
the coronary vein to the right auricle, whence it flowed into a vessel or
dish.   I poured half an  ounce of slightly acid water into the pericar-
dium.  At first the injected water exhibited no sign of acidity ; but in
five or  six minutes  it presented unequivocal marks of it.
  Absorption then  can take place without the assistance of this  sensi-
bility,  as well  as of this insensible organic  mobility, which is supposed
to be in the ultimate vascular  extremities, in  the absorbing mouths, as
they are called.  But do these mouths really exist?  Do the last capil-
lary branches terminate abruptly with a laige opening on  the surface of
the membranes or in the texture of the organs ?  Can  the  absorbed
fluids pass through  their parietes as oxygen does in the lungs to  arrive
at the blood which  it modifies ?  We are unable to make experiments on
these small vessels, that are not cognizable by our senses ; let us make
them on the large  ones, and if they permit  fluids, in  which they are
immersed, to pass through them, for a stronger reason we may suppose
that it takes place in the capillaries, whose parietes are so much more
delicate and consequently more  permeable.   Now we have confirmed
by experiments what we had suspected ; the first  attempts were made
on dead vessels.
  I took a portion  of the external jugular vein of a dog ; I stripped it
of the  surrounding cellular texture ; I attached to each of its extremi-
ties a glass  tube by means of which I  established a current of warm
water  through  its  interior;  I  then immersed the vein  into a  liquor
slightly acid.
  It is seen by the arrangement of the apparatus that there could not
be any commuuication  between the internal current of warm  water
and the external acid liquor.
  During the first minutes the liquid that I collected did not change its
nature; but after  five  or  six minutes the water  became perceptibly
acid ; absorption had taken place.
  The same experiment was  repeated on veins taken from human 
96             PHYSIOLOGICAL RESEARCHES
serous part of this fluid.   Why do not the red globules
pass  into  the serous  vessels, though there  exist a conti-

subjects;  the effect was  the  same;  it  was the same  also with the
arteries, but a li.ttle slower from the greater thickness of their coats.
  It remained to be seen if in a living animal absorption thus took place
through the parietes of a  large  vesse].  I know that  the textures that
were permeable after death, are almost all so during life, though the
contrary is generally believed.   If we inject into the pleura of a living
animal a certain quantity of ink, at the  end of an  hour, and often
sooner,  we  shall find the  pleura,  the  pericardium, the  intercostal
muscles, and the surface of the heart itself, evidently of a black colour.
It  is true  that the signs of this exudation are  not always  apparent.
Thus  after  death,  the transudation of the  gall  bladder  is rendered
evident by the colouring  of the neighbouring parts.  During life, on
the contrary, as fast as the colouring particles are deposited, they are
absorbed by the serous membrane which  covers the surrounding parts,
and carried  off by  the sanguineous current which runs through this
membrane and the subjacent organs.
  From these considerations we must believe that absorption may take
place through the parietes of the vessel during life  as after death.  To
be satisfied of this I made  the following experiment;
  I took a young dog of about six weeks old.   At this age the vascular
parietes are  delicate, and consequently more likely to render the expe-
riment successful.   1 laid  bare one of the jugular veins; I insulated it
perfectly in  its whole length ; I stripped off carefully every thing which
covered it, and especially the cellular texture and some small vessels
that ramified on it; I placed it on a card, that it might  not be in con-
tact with  the surrounding parts ;  I then let fall, on its  surface and
opposite the middle of the card, a thick aqueous  solution of an alcoholic
extract of nux vomica, a substance  the action of which  is  very power-
ful on dogs; I took care that none of the poison could touch any thing
but the vein and the card, and that the course of blood was free in the
interior of  the vessel.  Before the fourth minute, the effects that  I
expected appeared, at first feeble, but afterwards with so much power
as to render inflation of the lungs necessary to prevent the  death of the
animal.  I repeated this  experiment  on an  adult animal of  a much
larger  size than the  preceding one; the same effects  appeared but
slower, on account of the  greater thickness of the parietes; they began
to appear in fact after the tenth minute.
   After satisfying myself with this result respecting the veins, I thought 
ON LIFE AND DEATH.                  97
nuity of canal ?   The cause  by  no  means consists in the
disproportion of the vessels to the globules  as Boerhaave

I would ascertain if the arteries exhibited analogous properties.  These
vessels are in a less favourable condition; their texture is less spongy
than that of the veins and with an equal caliber, their parietes are much
thicker.  It  was easy then to foresee, that if the phenomenon of absorp-
tion showed itself, it would appear much slower than in the veins;  this
was confirmed in an experiment on two  large rabbits,  in whom I dis-
sected perfectly clean one of the carotid arteries.  It was more than a
quarter of an  hour before the solution of nux vomica  passed through
the parietes  of the artery.   As soon as I saw the symptoms of poisoning
distinctly, 1  stopped moistening the vessel ; yet one of the rabbits died.
In  order then to convince  myself that  the poison  had really passed
through the arterial  parietes, and  that it had not been  absorbed by
small veins which might have escaped my dissection, 1 carefully detach-
ed  the vessel that had  been  used in  the  experiment; I cut it open in
its  whole extent, and I made those who assisted metas te a little of the
blood, that was still adhering to the internal surface; they all perceived
 in it, and I did myself, the extreme bitterness of the extract of the nux
vomica.
  To these experiments may be  objected a fact that is observed, which
 is,  that absorption does not take place  the same under  all circum-
stances ; its activity is  redoubled or diminished,  according to the state
 of some other functions.   Thus during  a paroxysm of fever, a medicine,
 which would usually act with great effect, often  produces, when  given
 in a double  or treble dose, no perceptible effect. Now if absorption,
 was a purely mechanical phenomenon, would it undergo modifications
 in  relation with those of the vital functions ?  Without doubt it would ;
 for these modifications of the functions  may  introduce new physical
 circumstances favourable or injurious to the production of a mechanical
 phenomenon.  Thus in the present case, the state of fever, by accele-
 rating the circulation distends with  blood the arteries and the veins.
 The fluid that is  to be absorbed  must pass from the exterior  to the
 interior of  these vessels.  Now it may  be easily conceived, that the
 quantity of blood which they contain must have a great influence upon
 the production  of the  phenomenon by the greater  or less degree of
 tension of their parietes.   This  is  moreover completely confirmed by
 experiment.
   We can, without producing a very great disturbance in the functions,
 increase at pleasure the quantity of fluid which passes  through the
                 13 
98
PHYSIOLOGICAL RESEARCHES
has taught.   The  breadth of the  white vessels  might be
double  or  triple that  of  the red  vessels, and  still the

blood-vessels, by carefully injecting into the veins water the tempera-
ture of which is near that of the blood.  An artificial plethora is thus
produced, followed by very curious phenomena, of which I shall have
occasion  hereafter to speak.  One day while making this experiment,
the idea occurred to me of seeing what influence the plethora thus pro-
duced would exert upon the phenomenon of absorption.
  In consequence,  after  having injected into  the  veins  of a dog of
middle size about a quart of water, I placed in the pleura a small dose
of a substance, the effects  of which  were well  known to me.   These
effects did not show themselves till  many minutes after the period in
which they usually appear.  I soon made the same experiment on
another animal with the same result.
  In many other trials the  effects showed themselves at the period in
which they ought to have appeared ; but they were evidently weaker
and prolonged much beyond the ordinary time.
  Finally, in another experiment in which I had introduced as much
water as the animal could bear and  live, the effects did  not appear at
all.  I waited nearly half an hour  for effects which commonly show
themselves in two or three  minutes.  Presuming then  that  the disten-
sion of the vessels prevented the absorption, I  endeavoured to  satisfy
myself of it, by seeing if after the  distension  had ceased, absorption
would  be any longer prevented.  In consequence, I bled  the animal
copiously  from the jugular, and I saw, with the  greatest  satisfaction,
the effects appearing as the blood flowed out.
  It was  proper  to  make the  opposite experiment, that is to say to
diminish  the quantity of blood, in order to see if absorption  would take
place sooner.  This took  place in  fact, as  I  thought it  would ; about
half a pound of  blood was taken from an  animal;  the  effects, which
did not usually appear till  after the second minute, showed themselves
in thirty seconds.
  Yet it might still be suspected, that it was less the distension  of the
blood-vessels than the change  of the nature of  the blood that opposed
absorption.  To remove this difficulty I made the following experiment;
a dog was bled copiously;  the  place-of  the  blood which he had lost
was supplied by water at the  temperature of 40 degrees of the centi-
grade thermometer, and a certain quantity  of a solution  of nux vomica
was  introduced  into the  pleura   The  consequences  of  it  were as
prompt arid as powerful, as if the nature of the  blood  had not been 
ON LIFE AND DEATH.
99
globules of the latter colour would not pass into them, if
tiiere were not to exist a relation between the sum of the

changed ; it was then to the dist&nsion of the vessels that  must be
attributed the want or diminution of absorption.
  The consequences that may be deduced from the experiments I have
just related will  acquire  new force, if we connect with these  facts a
multitude of pathological ones, which are every day seen ; such as the
oure  of dropsies,  engorgements  and  inflammations  by bleeding; the
evident want of  action of medicines at  the moment of a violent fever,
when  the vascular system is powerfully  distended ; the practice of
certain physicians who purge and bleed their patients before administer-
ing active medicines to them *, the employment of cinchona at the period
of remission for the cure of intermittent fevers; general or partial oedema
from  organic disease of the heart or lungs, and the application of a liga-
ture upon the extremities after a puncture or a bite of a venomous animal,
to prevent the deleterious effects which are the consequence of it.
   On  the  whole, I  think, it may be concluded  from the preceding
experiments that the  capdlary attraction of the small vessels is one of
the principal causes of the absorption called venous.  If the lymphatics
do not appear to enjoy in the same manner  the faculty of absorption,
it probably arises not from  the nature of the parietes, the physical
properties of which are nearly the same as those of the veins, but from
the want of a continuous current in their interior.
   In  this note I  have brought together the absorption of the gases and
that of fluids.  This resemblance holds only as it  relates to the perme-
ability of the textures by these  two orders of bodies.   As to the cause
of the absorption of  the two, it cannot be  the same, since  gases are
not subjected to capillary attraction.*
   * Note by the  Translator of Magendie^s Additions.—In the preceding
note  M. Magendie has not done justice to Mr. Hunter.   Without enter-
ing at all into the examination  of the question, whether absorption is
performed by the lymphatics or the veins, it is due  to Mr. Hunter to
contradict the assertion,  that "he overthrew the ancient theory by five
experiments  only.''''   He was not a man  who adopted  his  opinions
loosely or on slight  grounds, and in  the present  case he performed
between twenty and thirty judicious  and satisfactory experiments, in
 the presence of several physicians and  surgeons.  It is true that these
 were  performed on five different animals only, but if the result  were
 uniform, this number was as good as five thousand or any other one that
 could be named.                                          G.  II.
   (See Hunter's Commentaries  and Cruikshank on, the Absorbents.) 
100
PHYSIOLOGICAL RESEARCHES
sensibility of the vessels, and the nature of the globules.
Neither will the chyme pass into the Choledochus, though
the diameter of this canal be very much larger, than that
of the attenuated molecules of the aliments.   Now in the
healthy state,  the  quantity of sensibility in the white
vessels being inferior to  that in the  red  ones, it is evident
that the relation necessary to the admission of the colour-
ed globules  cannot exist.  But if any cause should exalt
their powers, their sensibility will be on a par with that
of the latter set of vessels, and the passage of the fluids
till then refused, will take place with facility.
  Hence it  happens, that  those  surfaces, which  are the
most exposed to such agents as exalt the sensibility, are
also the most  subject to  local inflammation, as  may be
remarked in the  conjunctiva and  the  lungs; at which
time such is usually  the  increase  of sensibility  in  the
part, that of organic,  which it was, it  becomes animal,
and transmits  to  the  brain the  impressions, which are
made upon it.
  Inflammation lasts as  long as there subsists an excess
of sensibility ;  by degrees it diminishes, the  red globules
cease to pass into the serous vessels and resolution takes
place.
  From this it may be seen that the theory of inflamma-
tion is  only a natural consequence of  the  laws, which
preside over the  passage of the  fluids into their respec-
tive tubes; hence also  it may be easily conceived how
unfounded are  all hypotheses, which  are borrowed from
hydraulics,  a science, which  never  can  be really applied
to  the  animal  ceconomy,  because  there is no  analogy
between a set of inert tubes, and a series of living ducts.*
  * Those theories no doubt  are very incomplete that are borrowed
from hydraulics, and probably will be so for a long time ; but it arises
from this, that  the  science on which it is founded, hydrodynamics, is still 
ON LIFE AND DEATH.
101
   I should never have finished were I to enumerate the
consequences of this principle in the  phenomena of the
living mam  The reader will easily enlarge the field  of
these consequences, the whole of them will form almost all
the great data of physiology, and the  essential points of
the theory of diseases.
   But no  doubt it will be asked, why the organs  of the
internal life have received from nature, an inferior degree
of sensibility only, and why they do not transmit to the
brain the impressions, which  they receive, while all the
acts of the animal life imply this  transmission? the reason
is simply  this, that all  the phenomena, which establish
our connexions with surrounding objects ought to be, and
are in fact under the influence of the will; while all those,
which serve for the purpose of assimilation only, escape,
and ought indeed to escape such  influence.   Now for a
phenomenon to  depend  upon the  will,  it  is evidently
requisite that the individual be possessed of a conscious-
ness  of such phenomenon,  to be  withdrawn from  the
influence of the will, there should exist no such conscious-
ness.
but little advanced.  A great advance will unquestionably be  made in
physiology, when we shall arrive at a knowledge of the course of a fluid
in a system of canals, which have the same physical conditions as  the
system of arterial and venous vessels.  But it will be a long time before
science will have arrived at that point.  Is it necessary for this to make
no use, in the explanation of the circulation, of the few facts which are
known upon the course of the fluids ?  Is it necessary to  enter entirely
into the field of hypothesis, to suppose in the small vessels a sensibility
and a contractility which evidently do not  exist in the large ones ? I
cannot believe it, and I think even that if this hypothesis should be
true, and if there should be  demonstrated for the capillary vessels,
those properties which are attributed to  them, and which would have
an influence on the course of the blood, we should then know but one
of the conditions of  this very complicated problem, and this would  not
in any degree do away the necessity of knowing all  the mechanical
conditions. 
102          PHYSIOLOGICAL RESEARCHES
V.  Of the two kinds of contractility, the animal, and
               the organic contractility.

  Contraction  is the ordinary  medium,  by  which  the
motion  of the animal  organs is effected;  some parts,
however,  move by dilating themselves, as  the iris, the
corpora cavernosa, the  teat and others; so that the two
general  faculties,  from  whence spontaneous  motion is
derived, are  contractility and  active  extensibility;  the
latter of  these  should  be carefully  distinguished  from
passive  extensibility, of which  in a short time we  shall
speak.  The  first is  a property of life, the second a pro-
perty of texture; but as yet there exist too few data  upon
the nature and  mode of the  motion resulting from the
former; it is exemplified in too small a number of organs,
for us to be enabled to  pay much attention to it in  these
general  considerations —Accordingly  we shall occupy
ourselves  only upon the  subject of contractility;  with
respect  to that of  active extensibility,  I  refer to the
writings of the physicians of  Montpellier.
   Spontaneous  motility,  a  faculty  inherent in living
bodies,  as well as sensibility, possesses two great modifi-
cations, which differ very much from each other, accord-
ingly as it is  examined  in the phenomena of one or the
other life.  There is an animal contractility, and there is
an organic contractility.
   The  one  being essentially  subject to the influence of
the will, has its principle in the brain, receives from the
brain the irradiations, which  put it in action, and ceases
to exist when the organs, in which it is observed, commu-
nicate no longer with the brain; it participates besides at
all times with the state of the  brain, has exclusively its
seat in  the voluntary muscles, and presides over locomo- 
ON LIFE AND DEATH.
103
tion, the voice, the  general  movements of the head, the
thorax and abdomen.   The  other, which  is not depend-
ent  on a common centre, has its principle in the moving
organ itself, is a stranger to  the influence of volition, and
gives rise  to  the phenomena of digestion,  circulation,
secretion, absorption, and nutrition.
   The two are quite distinct in all cases of violent death;
such death annihilates at  once the animal  contractility,
and  allows, for a longer or shorter time, the organic con-
tractility to be exercised;  they  are  essentially distinct
also  in all cases of asphyxia; in these, the first is entirely
suspended,  the  second remains in  activity ; lastly  they
are  distinct both  in artificial  palsy and in that which is
brought  on by disease.   In  these, the voluntary motions
cease ; the organic motions are unaltered.
   Both the one and the other kind  of contractility are
connected  with their corresponding kinds of sensibility.
They are  a  consequence of  them.   The sensation  of
external objects puts in action the animal contractility;
before the  organic contractility of the heart can be exer-
cised, its organic sensibility must  be excited by the influx
of blood.
   Nevertheless, the concatenation of these two kinds of
faculties is not always the same.  The animal sensibility
may be exercised, and  not be necessarily followed by the
exercise of its analogous contractility.  There is a gene-
ral relation between sensation and locomotion, but this
relation is  not direct and actual.   On the  contrary, the
organic contractility can never be separated from the sen-
sibility of the same  species; the re-action of the  excret-
ing tubes is immediately connected with the action, which
the  secreted fluids exercise  upon  them : the  contraction
of the heart  must necessarily succeed  the influx of the
blood into it.   But  authors  have by no means separated 
104          PHYSIOLOGICAL RESEARCHES
these two things, either in their considerations or their
language.  Irritability denotes at the same time the sensa-
tion excited in the organ from the contact of bodies, and
the contraction of the organ in reacting upon its excitants.
  The reason of this  difference in the  relation  of  the
two sensibilities and contractilities to each other is very
simple.   In the organic life, there is nothing intermediate
in the exercise of these  two faculties.  The same organ is
the term, in  which the sensation ends, and the principle
from whence the contraction begins.   In the animal life,
on  the contrary, there exists between  these  two acts two
intermediate functions,  those of the brain namely, and
the  nerves, and  these by not being  brought  into action
may interrupt the relation  in question.
  To the same cause must we refer the following observa-
tion.  In the organic life  there  always exists a rigorous
proportion between  the sensation,  and  the  contraction.
In the animal life the  one may be exalted  or lowered,
and the other not affected by such change.
                                                    i
VI. Subdivision of the Organic contractility into two
                       Varieties.*

  The animal contractility is always  the same in what-
ever part of the body it is situated.  But there exist in the
organic contractility  two essential modifications, which
would seem to indicate a difference in their nature, though
  *Even in reasoning according to  the hypothesis  of Bichat,  and
admitting the existence of this organic  sensibility, it would always  be
inaccurate to say, that the contraction is uniformly in proportion to the
sensation.   How is it to be known in fact ?  Since  this sensibility is not
transmitted to a common centre, it might very well be excited without
our being  informed of it by  any apparent effect. Sometimes also a
very evident contraction would correspond to the slightest excite-
ment. 
ON LIFE AND DEATH.
105
 there  be only  diversity  in outward  appearances.   This
 difference  is  sometimes  visible,  at  other times  though
 really existing, it cannot be seen  by inspection.
   The sensible organic contractility may  be observed in
 the heart, in the  stomach,  intestines, bladder,* and other

  * The contractility in the different organs  in which we  can observe
 it does  not exhibit characters  so  striking  as  those  which  Bichat  here
 assigns  to it,  and the motions  which he  ranks in the same class  have
 the  greatest  differences among  them.   To  be  convinced how  little
justice  there  is in this division, it will be sufficient to trace the progress
 of the food,  along its  whole course, to  the interior of  the  digestive
 canal.  The first act which is  presented to our observation is entirely
 voluntary  ; this is mastication ; the act  which follows it is not so com-
 pletely  so.  Deglutition in fact can sometimes take place against the
 will, if a body of a proper consistence is at the entrance of the  pharynx.
 We have but an  imperfect control  over the muscles of the uvula and
 the velum palati, if we wish to move these parts  separately;  we  have
 perhaps less  power  still over  the  contraction of the muscles of the
 pharynx,  though they do  not  appear  to differ from  the  locomotive
 muscles, either in their symmetry, or in  the arrangement and  colour of
 their fibres, or in the nerves which  they  receive; nor finally do  they
 differ in the sudden, instantaneous  contraction, wholly different  from
 the  slow contraction, the vermicular motion of the stomach and intes-
 tines.
  After having passed the pharynx, the alimentary mass enters the
 oesophagus.   The motions are there still under  the influence of the
 nerves ; but they are not at all under the influence of the will.  The
 muscular  layer which produces them has not the appearance, the red
 colour of  the  voluntary muscles ;  but  it still preserves  something  of
 the  sudden  motion  of  their  contraction.  Hence we  see,  that the
 motions of the oesophagus cannot be ranked either  among the motions
 of organic life, since  they cease by the division of the nerves, or among
 those of animal life,  as they are not  under the influence of the will.  It
 is remarkable also that  Bichat, who,  in this and the following paragraph,
 announces the characters of the different kinds of contractility,  does
 not speak  of  the oesophagus, whilst he offers as an example the motions
 of the bladder, the heart, the stomach and the intestines.
  When Bichat  wrote this work, hardly any thine of the motion?  of
 the oesophagus was known, except from the writings of Fiedler,  who
 made but  four experiments on  the subject.   I wished to observe the-m
                14 
106            PHYSIOLOGICAL RESEARCHES

organs.   It is exercised upon very considerable quantities
of the animal fluids.
myself, and I have discovered* many facts which I think interesting ; I
shall relate them  here as I described  them in a memoir read to the
Institute in 1813.  Before attempting to  ascertain what part the oeso-
phagus took in the passage of the food, it was  proper to ascertain its
state when it was  supposed to be at rest.  In the first experiments, I
noticed an important phenomenon, and  which hitherto had escaped the
observation of physiologists, viz, that the  lower third of the oesophagus
has constantly an alternate motion of contraction and relaxation, which
appears to be independent of all foreign  irritation.  This motion appears
to be confined to  the portion  of the tube which is surrounded by the
plexus of nerves of the eighth pair, that is to say, to about its lower third ;
there is no trace of it in the neck nor in  the superior part of the thorax.
The contraction appears like a peristaltic motion, it begins at the junc-
tion of the superior two  thirds  with the  inferior  third, and is continued
to the insertion of  this tube in  the stomach.  When  the contraction is
once produced, it  continues for  an  uncertain  time ; usually it is  less
than half an hour.  The oesophagus contracted  in this way in its lower
third is hard like a cord powerfully stretched.   Some persons whom I
have made feel of it in  this state have compared it to a rod.  When
the contraction has lasted  the  time  I have just  mentioned, the relaxa-
tion takes  place suddenly and simultaneously in  each  of the contracted
fibres;  in  some cases, however, the relaxation seems to take place  from
the superior fibres towards the inferior ones.  The oesophagus examined
during  the state of relaxation  exhibits  a  remarkable  flaccidity, which
contrasts wonderfully with the state of  contraction.
   This alternate motion is dependent on the nerves  of the eighth  pair.
When these nerves are  cut in an animal, this motion entirely ceases ;
the oesophagus contracts no more, but it is not in a state of relaxation ;
its fibres without  the control of  nervous influence  shorten; it is  this
which produces, so far as the  touch is concerned, an intermediate state
between contraction and relaxation.
   When the  stomach is empty or half  full of food, the contraction of
the oesophagus recurs at much longer intervals; but if the stomach be
powerfully distended by any  cause, the contraction of the  oesophagus
is usually  very powerful, and continues for a much longer time.   I have
seen it, in cases of this kind,  continue  more than ten minutes ; under
the same circumstances, that is to say, when the stomach is excessively
full, the relaxation is always much shorter.
   If during the time of contraction, we wished,  by mechanical pressure 
ON LIFE AND DEATH.
107
   The  insensible organic  contractility is  that, by  virtue
of which the excreting tubes re-act upon their respective

made on the stomach, to make a part of the aliments which it contained
pass into the oesophagus, it would be necessary, in order to accomplish
it, to employ a very considerable force ; and often even we should not
succeed.  It seems that pressure increases the intensity of the contrac-
tion, and prolongs  its duration.  If, on  the contrary, the stomach is
pressed during relaxation, it is  very  easy to  make the  substances it
contains pass into the cavity of  the  oesophagus.  If it be a liquid, the
slightest  pressure, sometimes  even  its own weight, or the tendency
which the stomach  itself has to contract, will  bring  about this result.
When the stomach is  laid bare and distended above  measure, fluid does
not usually enter into the oesophagus, because, as we have said, the dis-
tension of the  stomach is a cause which prolongs the contraction of the
oesophagus.
   The passage of a fluid in the  oesophagus is  usually followed  by its
entrance into  the stomach.  Sometimes however the fluid  is thrown out.
When it goes into  the  stomach, the oesophagus contracts nearly the
same as in deglutition, sometimes almost immediately after  it has entered
it; at  other times the oesophagus allows itself to be considerably dis-
tended before it pushes  it into the stomach.
   It was at the moment of deglutition that Haller observed the motions
of the oesophagus, and  the description which  he has given of them Is
very accurate for the two superior thirds of the canal ; but the  action
of the inferior third is essentially different; and this distinction  seems
to have escaped him.  Haller says that the relaxation of each circular
fibre immediately follows the contraction ; and  this is true of  the por-
tion of the canal  situated in the neck and in the superior part  of the
thorax;  but it is not  accnrate for the inferior  portion, in which we see
that the  contraction of all the  circular fibres is continued long after
the  entrance  of solids or fluids into the stomach.   At this  moment the
mucous membrane  of the cardiac extremity of the oesophagus, pushed
by the contraction of  the circular fibres, forms a very considerable
projection into  the cavity of the stomach.  The contraction usually
coincides with the period of inspiration, when the  stomach  is  more
strongly compressed ; the relaxation takes place most often at  the time
of expiration.   When the aliments have once  entered the stomach, it
is this contraction of  the inferior  part of the oesophagus which opposes
their return.   The  resistance that is offered at  the other orifice  is not
 of the same species.  In living animals-, whether the stomach be  empty
 or full, the  pylorus is uniformly shut  by the  contraction of its fibrous 
 10S             PHYSIOLOGICAL RESEARCHES

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

 ring and the contraction of its circular fibres.  There is frequently seen
 in the stomach  another  contraction, at one or  two inches  distance,
 which  appears to  be designed  to prevent  the aliments from arriving
 at the pylorus.   We perceive also irregular  contractions, beginning at
 the duoderum, and extending to  the  pyloric portion of the  stomach,
 the effect of which is to  push  back the aliments towards the splenic
 part.
  The aliments  remain  in the  stomach  long  enough to  undergo no
 other modifications than those which result from their mixture with the
perspiratory and  mucous  fluids, which are constantly found in it  and
renewed there.   During this time the stomach remains uniformly dis-
tended ;  but afterwards  the  pyloric  portion contracts in its  whole
 extent, especially in the part nearest the splenic portion, towards which
the aliments are carried.   Then there is found, in the pyloric portion,
 only the chyle mixed with some unchanged  aliments.  When there is
 accumulated in this part a quantity of it, which is never very considera-
 ble, there  is seen, after a moment of rest, a contraction at the extremity
of the  duodenum ; the pylorus and the pyloric portion soon  t<ike  part
in this  motion, and the chyle is forced  towards the splenic portion ; but
afterwards the  motion is in an inverse direction.   The pyloric portion,
which  allowed itself to be distended, contracts  from left to right, and
 directs the chyle tovvards the duodenum, which soon passes the pylorus
 and enters the  intestine.  The same phenomenon is repeated a certain
number of times, then it ceases, and commences again after sometime.
 This motion, when the stomach  contains  much food, is limited to  that
 part of the organ  nearest the  pylorus; but as it  becomes empty, the
motion extends, and appears  even in the  splenic portion when  the
 stomach is almost  entirely evacuated.  In  general, it  becomes more
evident at  the end of chylification.
  The motion which produces the progression of the chyle in the small
 intestines is very analogous to that of the pj'lorus; it is irregular, made
 at variable intervals, it is sometimes in one direction and sometimes in
 another, and sometimes  appears in many parts  at once ;  it is always
 more  or less slow,  it produces  changes of relations  in  the  intestinal
 circumvolutions,  and it is entirely beyond  the influence of the will.
   We should form a very  false idea of the motions of the  small intes-
 tines  during  digestion, if  we  judged of them  by those  which these
 intestines  exhibit in an  animal  recently killed.   In this  case, it is not
 the annular fibres only that enter  into action, so as to exhibit, by thek 
ON LIFE AND DEATH.
109
the  nutritive juices, and the lymphatics  upon the sub-
stances which excite their open extremities; upon all these

successive contractions, a vermicular motion.  The  longitudinal fibres
act also  in a very conspicuous manner, and produce a rolling of the
intestinal circumvolutions, which change their relations at every instant.
These  motions  are never more evident than when the whole mass of
intestines is removed from a living animal.
  The motions  of the large intestines have nearly the  same characters
as those of the  small intestines, like these last, they are not  always in
the same direction, but push  the  substances which are  contained in
their cavity, sometimes towards the ileum and sometimes towards the
anus.  But  by means of this  motion, these  substances which have
already the character of feces, can never re-enter the small intestines.
The cause that prevents  their return is different from that which  pre-
vents the return  into  the stomach of the substances  contained in the
duodenum.  The obstacle in this  case, we have  said, is  produced by
the  contraction  of the contractile rings,  which  are found  at the
extremity o( the  two cavities ; in  the other, it is  produced  by a cause
purely mechanical, by the arrangement of the ileocecal valve.   Hence
it follows, that  if  the  mode of contraction of the  different parts of the
intestinal canal be perverted  by any  cause, it might happen that their
contraction towards the pylorus would  not take place  when the duode-
num was affected  with its  anti-peristaltic  motion, and then  the  sub-
stances contained in it, pushed  by the contraction.of the annular fibres,
would re-enter the stomach.   At the coecum, on the contrary, as the
obstacle is purely mechanical, so long as  the ileo-coecal valve is not
broken, it will  present an insurmountable obstacle to  the  return of the
feces into the small intestines.
  The motions of the large intestines, sufficient to carry the  feces into
the rectum, would not, in a state of health, be powerful enough to
expel  them entirely, by overcoming  the resistance which  the sphincter
constantly presents; in expelling the feces, the contraction of the intes-
tine is assisted  by the pressure which  arises from the lowering of the
diaphragm, and by the contraction of the abdominal muscles.
   We have  just pointed out the  motions which  carry the alimentary
mass  along the  intestines.  We  may see that  they have  but little
resemblance among them.   The  only character that is  common to
them is that of not being under the influence of the  will.  Yet there
is an exception to this in some individuals who possess the  faculty of
ruminating.  (The will is seen exerting itself on the  production of other
sensible organic motions.  Bayle could stop at will the pulsation of his 
HO            PHYSIOLOGICAL RESEARCHES

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

heart.)  If we  examine the motions of the digestive tube when it is
free of aliments, we see their difference in a manner not less striking.
The oesophagus  exhibits those alternate motions that we have described ;
a very  powerful contraction of its inferior  third, and then suddenly the
most complete relaxation.   In the stomach we see only some undula-
tions, that go irregularly from one orifice to another.  In the intestines,
these motions exhibit nearly the same regularity^ but the groove formed
by the  contraction of the annular fibres is deeper, and the uhdulatory
motion is not so slow.   If a stimulating  medicine is introduced-into the
stomach, these  contractions become more  evident, and the motions
more rapid ; but they always preserve the same character.  The con-
traction takes place progressively, and  never in the sudden manner of
a muscle of locomotion.  Of  all the substances  which can be used to
ascertain these motions, there  is no one  whose action is more efficacious
than veratrine,  a new  vegetable  alkali extracted from  the  veratrum
sabadilla.   If the external parietes of the digestive tube be excited by
any stimulus, by touching it with the finger, by a puncture,  or by the
galvanic  fluid, there is  in the  oesophagus  a sudden contraction of the
longitudinal and circular fibres, which narrows the organ  and  shortens
it at the same time ; the relaxation  takes place instantaneously and in
as striking a manner.   In the stomach, no motion is perceived in the
direction of its  length ; we see only an annular  contraction, which is
developed slowly at the excited point,  and which is  usually not trans-
mitted to the neighbouring parts.  In the intestines, the excitement
produces a very decided contraction, and very often in the neighbour-
ing parts a kind  of peristaltic motion ; but this motion is always slow and
does not at all  resemble the sudden contraction  of the oesophagus.
  The difference between the motions  of the oesophasus and those of
the other parts  of the intestinal canal is very remarkable in birds.  In
them the oesophagus appears to be entirely membranous; and yet it con-
tracts like a muscle of  locomotion ;  whilst the stomach, which has red
muscles very similar to the  locomotive  muscles,  has slow, gradual ver-
micular motions, like all the canal which  is below it.
  There exists finally between the motions of the intestinal canal a
difference relative  to the  manner in which they terminate.   Those of
the intestines,  but little sensible during life,  acquire at the moment of
death  a very great intensity ; whilst those of the oesophagus,  before so
distinct, cease  immediately, and in the  most complete manner. 
©N LIFE AND DEATH.
Ill
 precise idea may be given of both, by comparing the one
 with attraction, a power which is exercised upon the
 great aggregate of matter, and the other with the  chemi-
 cal affinities, the phenomena  of which take  place in the
 molecules  of different substances.   For the  purpose of
 explaining this  difference, Barthez has compared the one
 to the second  hand of a watch, which traverses the cir-
 cumference in a very  apparent manner, and  the other to
 the  hour hand, which moves also,  but whose motion is
 not distinguishable.
   The sensible  organic contractility nearly answers to the
 irritability of authors ; the insensible organic contractility
 to what is  called tonicity.  But these words seem  to sup-
 pose in the properties, which they indicate a  difference of
 nature, while this difference exists only in appearance.  I
 therefore prefer employing for both a common term.  It
 designs their general character, that of appertaining to the
 interior life, and  their independence with regard to the
 will.   To  this  term  I  join  an  adjective expressive of
 the particular attribute of each.
   In fact  we  should  possess a very inaccurate idea of
 these two modes of action, were  we to consider them as
 proceeding from different principles.  The one is but the
 extreme of the  other ; they are both connected by insen-
 sible gradations.  Between the obscure but real contrac-
 tility,  which is necessary to the nutrition of the  nails,
and the hair, &c. and that which  we see in the motions
 of the stomach, and  intestines, there exist innumerable
shades of  this  property, which  serve as transitions be-
twixt its perceptible degrees ; such are the motions of the
dartos,* of the arteries, and of certain parts of the cutane-
ous organs.
  * It is not the dartos that contracts in the motions of the scrotum, it
is the skin itself that produces that vermicular motion that is observed 
112
PHYSIOLOGICAL RESEARCHES
    The  circulation will  give us a very good idea of this
 graduated enchainment of the  two  kinds of organic  con-
 tractility.   The  sensible  organic  contractility   presides
 over  this  function in  the  heart  and large vessels,t  by

 in this part.  This motion can be produced by stimuli of very different
 kinds;  by the impression of cold, by pinching the skin  or by fear.  I
 have seen these motions so great in  a man on whom I was about to
 operate for hydrocele, that  I  was obliged to wait for a  long time  for
 fear of  wounding the testicle,  which,  hy  those motions,  ascended and
 descended precipitately.

  t It might be thought from this expression, that Bichat  supposed that
 the great  arteries influenced the course of the blood by an  active con-
 traction analogous to the muscular contraction ;  but this was not  his
 opinion.   He only wished to say, that the blood continued to move in
 the great arteries solely by the  influence of the heart.  This contraction
 of the great arterial  trunks  has been heretofore  maintained by many
 anatomists, and is even at  present by some.  There  are at  the present
 day three  principal theories relative to the circulation.
  In the first, it  is contended  that all the parts of the arterial system
 are  irritable, and that they contract like  the muscular texture; many
 even add  that they  can  dilate spontaneously, as takes place every
 instant in  the heart.   According to this supposition, the  arteries alone
 would be able to continue the course of the blood.
  In the second  opinion, which is that of Harvey,  and  which is still
 adopted, more particularly by the English  physiologists, it is affirmed
 on the contrary, that the arteries are not contractile  in any point; that
 if they do contract  in  certain cases,  it is in  virtue of  that property
 common to all the solids, by which they return upon themselves, when
the  cause that has distended them ceases to act.  The  partisans of this
 opinion conclude that the arteries have not and cannot have  any influ-
 ence upon the motion of the blood which  runs through them, and that
 the  heart is the principal, and as it were, the sole agent of the circula-
tion.
  Finally  the third opinion, that which now prevails most generally in
 France,  consists in a union of the two  preceding ones; the trunks and
principal arterial branches are considered  as  incapable of acting upon
 the  blood; but this property is  attributed to the small arteries, and it is
 thought to be very great  in the last divisions of these  vessels.  Thus,
 in this mixed  opinion, the blood is carried by the  sole influence of the 
ON LIFE AND DEATH.
113
degrees  it  become  less  apparent,  in  proportion as  the
diameter of the vascular  system  decreases;  and lastly, it

heart in all the arteries of a considerable size ;  it is moved in part by
the influence of the heart and in  part  by  that of the parietes in the
smaller arteries, and finally it is moved by the sole action of the parietes
in the last arterial divisions.  This action  of the small vessels is also
described  as the principal cause of the course of the blood  in the veins.
   In a question  of this nature our opinion should  be determined by
experiments alone.   This presents many points  for elucidation.
   The first and the easiest  to  be decided is to ascertain if the arteries
are or are  not  irritable.  The problem was in some measure resolved in
relation to the great  arteries by the experiments of  Haller and  his dis-
ciples^ by Bichat himself,  and by those which M. Nysten  has made
upon man.  For the purpose of being more  perfectly convinced, I  have
sought,  by  all the known  means,  to  develop the irritability of the
arterial  parietes; I have  successively subjected them  to the action of
pricking instruments, of  caustics  and of galvanism, and I have never
perceived any thing which resembled a phenomenon of irritability ; and
as those who maintain the irritability of the arteries  pretend that if we
do not perceive the contractions, it is because the experiments are made
on too small  animals, in whom the effects  are but slightly apparent in
consequence of  the small diameter of these canals, I have  repeated the
experiment on large  animals,  on  horses and asses, and I have never
observed any other motions than the communicated motions.
   As the great arteries show no contraction, we  ought to believe that
the small  ones would not;  but as among the physiologists who reject
the irritability of the arterial trunks, some like  Haller,  do not speak of
the branches,  others accord  to them  contractility, it becomes necessary
to test this question  by experiment; now these small vessels, like the
larger ones, remain perfectly immoveable under the action of the scal-
pel, caustics and a stream of galvanic fluid.
   Irritability does not exist then  in the large  or the  small  arteries.
Respecting the  last arterial division*, as the vessels which form  them
are so small that they cannot come under the cognizance of the senses,
at least in a state of health, no one can affirm or  deny that they are
irritable.   Yet from analogy we ought to conclude, that they have no
sensible motion.  In cold-blooded animals, in fact, it is easy to see the
blood circulating in these vessels, and even passing into the veins; now
the vessels themselves appear  to be completely  immoveable.
   As the arteries cannot act upon the blood  by contracting in the
                 15 
114             PHYSIOLOGICAL RESEARCHES

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

manner of muscles, must we conclude that they have no action upon
this fluid, and that they are in relation to it nearly like  inflexible canals ?
I am very far from thinking so.  If in fact the arteries had no influence
upon  the blood, this fluid, moved by the sole  impulse of the  heart,
would, from its  incompressibility, be alternately in  motion and at rest.
This is indeed what Bichat thought,  and  what he  has advanced in his
other works; it is what  has been since maintained in a more  formal
manner by Dr.  Johnson  of London.  It is however very easy to prove
that it is not in  this way that  the  blood is moved  in  these vessels.
Open a large artery in a living animal, and the  blood will escape  in a
continuous  jet,  but by jerks; open a small artery, and the blood will
flow out in  a continuous  and uniform jet.  The  same phenomena take
place in man if  the arteries are  opened, either by  accident or in surgi-
cal operations.  The heart being unable to produce a continuous flow,
since  its action  is intermittent, it must be then that  the arteries act upon
the blood ;  this  action  can only be the disposition which they have to
contract, and even to  obliterate their cavity entirely.   Bichat thought
that his tendency to narrowing was not sufficient in the arteries to expel
the blood contained in their cavity.   lie maintains that the vessel does
not contract upon itself  only when the  blood has  ceased to distend it.
If it were so, the  arteries would be equivalent to inflexible canals, and
the course  of the  arterial blood  would not be continuous; but we can
easily demonstrate that  the  force with which the arteries contract is
more  than sufficient to drive  out the blood that they contain.
   When  two ligatures  are  applied at  the  same time  and at some
centimetres distant upon  two  points of an  artery which furnishes no
branches, we have a portion of artery in which  the blood  is  subjected
only to the influence of  the parietes.   If we  make in this portion of the
vessel a small opening, almost all the blood that it contains is immedi-
ately  thrown out, and  the  artery is much contracted.   This experiment
has been  known for a long time, and uniformly succeeds.  The following
is one of my own, and places, it seems to me, the phenomenon in a very
clear light.   I laid bare  the crural artery and vein  of a dog to a certain
extent;  I passed  under these vessels, near the trunk, a string, which  I
afterwards  drew tightly at  the posterior part of the  thigh, so that  all  the
arterial blood should come to the limb by the crural artery, and  all the
venous blood return to the  trunk  by the crural vein; I then applied  a 
ON LIFE AND DEATH,
115
   Should we consider irritability as a property inherent
exclusively in the muscles, as being one of the  characters

ligature upon the artery, and this vessel was very soon completely empty
in the part below the ligature.
  It is then satisfactorily proved that the  force with which the arteries
contract  upon themselves is sufficient to expel the blood they contain.
But what is the  nature of this  contraction ?  We  have proved that it
cannot be attributed  to irritability.   Every  thing  leads to the  belief
that it should , be referred to the very great elasticity which the arterial
parietes enjoy, an elasticity that, is brought into action, when the heart
forces a ce.rtain quantity of blood into the cavity of these vessels.   This
property of the  arteries  being  known, it is easy to conceive how the
principal  agent of the  arterial  motion, being alternate, the course of
fluid is yet continuous.   The elasticity of the arterial parietes is similar
to  that of the reservoir of air in certain pumps  with  an  alternate
action, and which notwithstanding throw out the fluid in  a continuous
manner.
   It is not enough to know the kind  of influence which the contraction
of the arteries has on the motion of  the arterial blood ;  it is necessary
to know if this contraction does not influence in a sensible manner the
course of the blood  in the veins.  This is elucidated  by the  following
experiment.  Lay bare, as in the preceding  experiment, the  crural
artery and vein of a  dog; tie the limb  strongly,  taking care not  to
include these vessels; afterwards tie  the crural  vein, and incite a small
opening in it below  the ligature, of  one  or two lines  in  length; the
blood flows out in a continuous jet.  If the artery be compressed, so as
to intercept  the  course of blood in  it, the jet still continues a  short
time ;  but it is  seen sensibly to diminish, as  the  artery is becoming
empty.  It  at length  ceases entirely when  the  artery is completely
emptied ; and though the vein remains distended with  blood along its
whole extent, it does not  flow out at the small wound.  If the  com-
pression  be taken off of the artery, the blood enters it with force, and
almost at the same  instant it  begins again to flow from the opening in
the vein, and the jet is reestablished as before.  If we check the course
of  the blood in the artery, there is but a feeble jet from the vein ;  it is
the same if the passage of  this  fluid is  alternately intercepted and  per-
mitted.
   I make the same  phenomenon evident in another way; I introduce
into the crural  artery the extremity of a syringe filled- with water  at
the temperature of SO degrees of the centigrade  thermometer; I push 
116           PHYSIOLOGICAL RESEARCHES
by which they are distinguished from other  organs, and
should we call this  property by a name  expressive of its
peculiar seat  in  the muscle, we should conceive  it, if 1
mistake not, in a very different way from that in which
it naturally exists.
  It is true, that in this  respect  the muscles occupy the
first rank in the  scale of the animal solids ;  they possess
the  maximum of  the organic contractility ;  but  every
living organ  acts, as they do, though  in  a  manner less
apparent  upon the excitant when  artificially applied, or
on the fluid, which in the  natural way is carried to  it for
the purpose of supplying  the  matter of secretion,  nutri-
tion,  exhalation, or absorption.
  Nothing in consequence  is more  uncertain than the
rule,  which is commonly  adopted  for pronouncing  upon
the muscularity  of any doubtful part;  for the rule con-
sists in ascertaining whether  such part does or does not
contract under the action of stimuli.
  It is thus, that a muscular tunic is admitted in the arte-
ries, although their organization entirely differs from that
of the muscles ;  it  is thus, that  the womb is pronounced
to be fleshy, however foreign to such structure; it  is thus,
that a muscular  texture  is admitted in  the  dartos, in  the
iris, and other parts, although no such structure be  observ-
able there.

the  piston slowly, and  soon the blood goes out by the opening in the
vein, at first alone and afterwards mixed with  water, and it forms a jet
the more considerable in proportion to the  force with which the piston
is pushed.
  To prove, as we have done, that the heart maintains an evident influ-
ence on the  course of the blood in the  capillary vessels, is  not to
advance that  these vessels  have no action on the motion of this fluid.
Many physiological  phenomena* on the contrary, prove that the capilla-
ries can aid with more or less  facility the passage of the blood, and
consequently sensibly influence its course. 
ON  LIFE AND DEATH.
117
  The faculty of contracting under the action of irritating
substances  like  that of the sensibility, is unequally dis-
tributed  among the organs ;  they enjoy  it  in  different
degrees.   We do not properly conceive it, if we suppose
that it belongs exclusively to some of them.   It does not,
as some  have imagined, possess its  peculiar seat  in  the
muscular fibre.   Life is the sole condition necessary to
all the fibres for enjoying it; their peculiar texture influ-
ences the sum only, wrhich they receive of it; it appears
that to such  an organic texture, is  attributed, if  I may
so express  myself, such a dose of contractility ; to such
another texture, such another dose, and so on ;  so  that to
employ the expressions, which I have used in treating on
the subject of  sensibility  (however  improper they may
be, yet capable alone of rendering my ideas) the  differ-
ences in the organic contractility of our different  parts,
consist in the quantity only, and not in the nature of this
property :  indeed it is with respect to quantity only that
this property varies,  accordingly as it is  considered in
the muscles, the ligaments, the  nerves, or the bones.
  If a special  mode of contraction ought to be  designed
for the muscles by a particular expression, such expres-
sion could  be only  derived  from the property which they
have of  contracting from  the influence of the will; but
this property is foreign to their texture,  and comes to
them from the  brain only; for  as soon as they cease to
communicate with this organ  directly  by means  of the
nerves, they cease also to be the agents of voluntary motion.
  These  considerations lead us  to  examine the  limits
which are  placed between the one and the other kind of
contractility.   We have seen that those which distinguish
the two modes of sensibility, appear to  be derived  only
from the greater or less proportion of this power;  that in
a certain proportion sensibility is of the animal kind, in a 
118
PHYSIOLOGICAL RESEARCHES
certain inferior proportion, of the  organic kind, and  that
frequently from an augmentation, or diminution of inten-
sity the two sensibilities reciprocally borrow their respec-
tive characters.   We have seen  a phenomenon  almost
analogous to this in  the  two  subdivisions of the organic
contractility.
   But this is not the case with  regard to the  two great
divisions  of contractility  considered  in  general.    The
organic can  never be transformed into the animal contrac-
tility.   Whatever be its increase of energy, it constantly
remains the same in its nature.   The  stomach, the intes-
tines frequently  assume  a  susceptibility  of contraction,
which  makes  them  rise up  and  produces in  them* the

  * Under no circumstance does the  stomach rise up, as Bichat calls it.
We have, in a preceding note, explained  the ordinary motions of this
viscus, in a  state of vacuity, during digestion  and under the influence
of an internal or  external stimulus.   None of these motions  are suffi-
cient to produce that sudden and energetic expulsion which charac-
terizes vomiting.   The opinion that the stomach rises  up in  vomiting
originated in a time of  ignorance, and we ought not to be astonished
that it should find advocates even in our day.  This has  not  however
been uniformly adopted ; Bayle  and P. Chirac opposed  it by experi-
ments ; Senac, Van Swieten and Duverney declared themselves against
it; but Haller, by adopting it, suddenly changed the views and removed
the uncertainty of a great number of physiologists, who, not taking the
labour of making experiments for themselves, loved to repose on the
faith of a celebrated name.  In physiology the opinions  of Haller are
certainly entitled  to very great weight; this is because this wise observer,
before announcing them as a  general proposition, was accustomed to
repeat many times the experiments on which he founded  them ;  but in
this  case he did not sufficiently  question the  use of  the  stomach in
vomiting.
  He has made four experiments only, less for the purpose of satisfying
himself that the  phenomenon existed, than to see  it such  as he sup-
posed it.  It is very difficult, even for the best mind, to dive«t itself in
observing, of the  ideas previously received without examination.  It
may then be believed,  that Haller in this way saw but superficially.
These considerations determined me some years since, to satisfy myself 
ON LIFE AND DEATH.
11$
most violent motions by the most simple stimuli, but these
movements preserve at all times their peculiar type, their

of what takes  place  in vomiting,  and of the part  which the  stomach
performs in it.   I shall relate  briefly the experiments which I tried on
the subject.  The first was made on a dog of middling size, whom I had
made to swallow six grains of emetic.   When this medicine had excited
nausea, I cut through the linea  alba opposite the  stomach, and intro-
duced  my finger into the abdomen.  At each nausea, I felt it very
powerfully compressed above by the liver, which the diaphragm pushed
down,  and below  by the intestines, which were  compressed by the
abdominal muscles.  The stomach also appeared  to  me  to  be com-
pressed ; but instead of  feeling it contract, it appeared to me, on the
contrary, to increase  in size.   The nauseas became more frequent, and
the more marked efforts, which precede vomiting, appeared.  Vomiting
finally took place,  and then I  felt my finger pressed with a force  truly
extraordinary.   The  stomach  rid  itself of a part of the  aliments  it
contained; but I  distinguished no  sensible  contraction in  it.  The
nausea  having ceased for a short  time, I enlarged the opening in the
linea alba,  for the purpose of observing the stomach.  As soon as the
incision was enlarged, the stomach  presented itself at it, and made an
effort to come out of  the  abdomen ;  but I prevented it with my hand.
The nauseas returned in  a few minutes, and I was not a little surprized
to see  the  stomach  filled with air, as they came  on.  In  a very little
time the organ had become three times its  former size ; vomiting soon
followed this dilatation, and it  was evident to all who were present, that
the stomach had  been  compressed without having experienced the
least contraction  in  its  fibres.  This  organ rid  itself of air and of a
portion of aliments ;  but, immediately after the exit of these substances,
it was flaccid,  and it was not till  after some minutes, that gradually
contracting, it  became nearly  of the same  dimensions as it was before
the vomiting.  A third vomiting took place, and we saw again  the same
series of phenomena.
  For the purpose of ascertaining whence the air  came, which, during
the nauseas, distended the stomach, 1 applied a ligature on the stomach
near the pylorus, so as to  close  the communication which exists  between
this organ and the small intestines, and  I  made the dog swallow six
grains more  of emetic in powder.   At the end  of half an  hour the
vomiting returned, accompanied by the  same phenomena.  The dis-
tension of the stomach by air was at least as  marked as in the preceding
experiment; besides  there was  no appearance of contraction of the 
120           PHYSIOLOGICAL RESEARCHES
 primitive  character;  and  have never been regulated- by
 the brain.   From  whence  proceeds this difference in the

 stomach, and  we  could  not  even clearly  distinguish its peristaltic
 motion.  The  animal  having been  killed  some moments after, in an
 experiment which had no  relation to vomiting, we examined  the abdo-
 men.  We saw that the stomach was of considerable size; its texture
 was flaccid  and not all contracted ; the ligature, at the pylorus, was
 not displaced,  and the air had not been able  to pass this way.
  Having repeated this experiment and uniformly obtained  the same
 results, I thought it right to conclude with  Chirac and  Duverney, that
 the mechanical pressure, exerted on the stomach by the diaphragm and
 the abdominal  muscles, is much concerned  in the production of vomit-
 ing ; now, if it were so, by removing this  pressure  from the  stomach,
 vomiting would be prevented ; experiment confirmed this conjecture.
  I injected into  the vein of a dog  four grains of an emetic  dissolved
 in two  ounces of common water,  (in this way  vomiting is  produced
 quicker and more  certainly;) I afterwards made  an opening  in the
 abdomen, and when the first efforts of vomiting began, I quickly drew
out the whole  of the  stomach,  which did not  prevent the  efforts  of
vomiting from continuing.   The animal made precisely the same efforts
as if he had vomited ;  but nothing came from the stomach ;  this organ
remained completely immoveable.  I  wished  then  to  see what would
be the effect of  pressure  made  on the stomach ;  for this purpose, I
placed my right hand on the anterior face of this organ, and my left hand
on the posterior face.  The pressure was hardly commenced  when the
efforts of vomiting, that is to say, the contraction of the diaphragm and
the  abdominal muscles powerfully recommenced.  I suspended the
pressure ; the abdominal muscles and diaphragm soon suspended their
contractions.   I renewed the pressure; the contractions of the muscles
began again; then I suspended  it; they ceased ; and  seven or eight
times in succession.  The last time, 1 made  a strong  and  continued
pressure; this  produced a real vomiting.  A part  of the substances
 contained in the  stomach was thrown off.  I repeated this experiment
on another dog;  I observed the same facts  ; only I remarked moreover
that the contractions of the diaphragm and the abdominal muscles can
 be produced by merely drawing by the oesophagus.
  In the experiment just related, the emetic substance was introduced
 into the veins,  and we have already remarked,  that the effects were
 quicker and more certain  than if the same substance had been intro-
 duced into the stomach.   This  alone should make  us suspect that 
ON LIFE AND  DEATH.
121
phenomena of  sensibility and contractility ?   I cannot in
a precise and rigorous manner resolve this question.

vomiting is not owing, as is generally believed, to the impression of the
emetic on the mucous membrane of the stomach ;  for, in this case, its
action ought to have been more prompt when it was placed directly in
contact with this membrane, than when it arrived at it with the blood
after having passed through the lungs and the four cavities of the heart.
For the purpose of elucidating this question  and of seeing if the con-
tractions of the muscles were the result of the impression produced on
the stomach, or if they were excited more directly by the emetic sub-
stance mixed with the blood, 1 made the following experiment:
  I opened the abdomen of a dog, and having brought the stomach out
at the opening, I tied with care the vessels that went to this viscus, and
I removed  the whole of it  (I ascertained  in some of the  preceding
experiments that a dog can live eight and forty hours after his stomach
has been removed.)  I made a suture in the  abdominal parietes; then,
having laid bare the crural vein, I injected into its cavity a solution of
two grains of emetic in  an ounce and a half of water.   I had hardly
finished the injection when the dog began to have nausea, and he soon
made all the efforts that an animal does when he vomits.   These efforts
appeared to me to be even more violent and longer continued  than in
ordinary vomiting.  The  dog remained  quiet about a quarter of an
hour; I then  renewed the injection, and I  forced  two grains more of
emetic into the crural vein;  this was  followed with the same efforts of
vomiting.  I repeated the experiment many  times and always with the
same success; but this experiment  suggested to me another, which I
performed in the following way :  I took a dog of good  size, from whom
I removed the stomach, as I had  done in the preceding experiment; I
introduced into the abdomen a  hog's bladder, to the neck of which I
had fixed, by threads, a canula of gum elastic; I  put the end of this
canula into the extremity of the oesophagus,  and I fixed it there also by
threads, so that the bladder resembled somewhat the stomach, and was,
like it, in communication with the oesophagus.  I  introduced into the
bladder about a pint of common water ;  this distended it, but  did not
fill it completely.  A suture was made in the wound of the abdomen,
 and four grains of emetic were injected into the jugular vein.   Nausea
 soon appeared, and was followed with real efforts of vomiting; finally,
 after some miuutes, the animal vomited up  abundantly the water from
 the bladder.
   It  followed evidently  from.the  preceding  experiments, that the
                 16 
122           PHYSIOLOGICAL RESEARCHES
VII. Of the extensibility and contractility of texture.

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

abdominal muscles and the diaphragm concurred to produce vomiting;
but it remained to be ascertained, what  was the part of the diaphragm
in the  production of this  phenomenon, and what was  that of the
abdominal muscles.
  If the diaphragm received only diaphragmatic nerves, it would be
easy to resist the contraction of this muscle by dividing these nerves;
but it also receives filaments from dorsal pairs, and these filaments are
sufficient to support its contractions. Yet experiment shows us, that
the diaphragmatic nerves  being cut, the contraction of the diaphragm
is very evidently diminished in power, and it may be said, without much
hazard of mistake, that this muscle loses, by this division, three quarters
of its contractile force.  It was then useful to see what influence the
division of these nerves would  have on the production of this phenome-
non.  I  made this division in the neck of a dog of three years old, and
I afterwards injected into the jugular vein three grains of emetic ; there
was only a very feeble vomiting; another injection of emetic, a quarter
of an hour after, excited  no  vomiting.   I  opened the abdomen and
endeavoured to produce vomiting by compressing the stomach.   The
compression,  though  very powerful and  long continued,  excited no
effort of vomiting ; it did not even appear to produce nausea. I thought
that this circumstance might be owing to the indiosyncrasy of the animal;
but having many times since  repeated this experiment, I  have  never
obtained any other result.
  In order to  understand  what part the abdominal muscles by their
contractions take in vomiting, we ought to observe what takes  place
when these muscles are unable to act.  There is but one way of com-
ing at this, which is, to separate these muscles from their attachments
at the sides of the  linea alba; this we have done on many animals ;
we have  detached  successively the external  oblique, the internal
oblique and the transversalis, leaving on the anterior face of the  abdo-
men only the peritoneum.   When these muscles are thus removed, we
can see very distinctly through the peritoneum, all that takes place in
this  cavity; we distinguish,  for example, perfectly  the peristaltic
motion of the stomach and the intestines ; and if the stomach contracts 
ON LIFE AND DEATH.
123
the fibres of the different parts.   These  are extensibility
and contractility.
   They both  succeed each other,  and are connected in
the same way, as in the vital  phenomena, the organic and
animal  sensibilities  are related  to their respective  con-
tractilities.
   Extensibility «f texture, or the  faculty of  being  dis-
tended  beyond the ordinary state by external impulse
(and in this it  is  distinguished from  the extensibility of

it will be easy to see it.  The abdominal muscles being thus detached,!
injected three grains of emetic into the  jugular vein, and  also  immedi-
ately nausea and vomiting took place by the contraction of the  dia-
phragm alone.  It was curious  to see, in the convulsive contraction of
this muscle, the whole intestinal mass pushed downwards, and  pressing
strongly against the peritoneum, which was ruptured in  some places.
In this case, the linea alba, formed by a very strong fibrous texture, is
the only part  which  resists the pressure of the viscera ;  its existence
then is indispensable to the action of vomiting; perhaps it performs an
analogous office  in the  ordinary state.   This  experiment proves  that
vomiting can be produced by the efforts of the diaphragm alone ; this
is also confirmed by the following experiment:
  I detached, as above, the abdominal muscles and laid bare the perito-
neum ; I afterwards divided the diaphragmatic nerves, and injected an
emetic into the veins.  The animal had some nausea, but nothing more.
Though I repeated many times  the injection of the emetic, I never was
able to produce any sensible  effort of vomiting.
   From the different experiments that we have just  related, and from
the  facts that we made known  in  a  preceding .note relative to the
motions of the oesophagus, we may  conclude,  without any hazard,
   1st. That vomiting  can take place without any contraction of the
stomach.
  2d. That  the pressure exerted immediately on the stomach by the
diaphragm and abdominal muscles,  appears to be  sufficient to produce
vomiting, when the occlusion of the inferior part of the oesophagus offers
no  obstacle to it.
   3d. That the convulsive contraction of the diaphragm and abdominal
muscles, in vomiting from  tartarized^ antimony and emetic substances
properly so called, is  the result of  a direct action of these substances
on the nervous system and independent of the impression felt by the
stomach. 
I
I
124          PHYSIOLOGICAL RESEARCHES

the iris,* the corpora cavernosa, &c.)  This extensibility,
I say, belongs  to  many organs.  The extensor  muscles
are very much lengthened in strong tension of the limbs;
the skin  accommodates  itself to  tumours ;  the  aponeu-
roses,  as  we see in ascites and pregnancy, are distended
by  what  is  accumulated  beneath  them.  The  mucous
membranes of the intestines, of the bladder ; the serous
membranes of  the  greater number of the cavities present
us with similar phenomena, when these  cavities  are full.
The fibrous membranes, the bones themselves are suscep-
tible of distension.   Thus in hydrocephalus  the  pericra-
nium,  and the  bones of the cranium, in spina ventosa and
other  analogous diseases, the extremities or the middle
of the long bones  experience a similar  distension.  The
kidneys,  the  brain,  and  the  liver, when abscesses are
formed in their interior, the spleen and  the  lungs, when
penetrated by a great quantity of blood, the  ligaments  in
articular dropsies, in short all the organs, under a thousand
different  circumstances, exemplify  this  property ;  a pro-
perty inherent in their texture, and  not precisely depend-
ing on their  life ; for as  long  as their  texture  remains
untouched, their extensibility subsists also, though they
themselves have ceased to live.—The  decomposition  of
the part, from  whatever cause it happens, is the sole term
  *The motions of the iris cannot be attributed to an active expansion
of an erectile texture; they are owing to the contractions of two
muscular layers, one of which is radiated and  enlarges  the opening of
the pupil, the other is orbicular and contracts it.
  The motions of the iris, like all those which  have muscular contrac-
tion for their cause, can be excited for a considerable time after death
by the galvanic fluid.  During life, the motions of the pupil are produced
in man, by the more or less vivid impression  of light on the retina. But
they are beyond the influence of the will; in  birds on the contrary, they
appear  to be entirely subjected  }o it.  In these animals, we can even
after death, and on an eye  entirely detached from the body, produce
the  motions of the iris by pricking the optic  nerve. 
ON LIFE AND DEATH.
125
of this  extensibility, in which the organs are passive at
all times, and subject to the mechanical influence of those
bodies which act upon them.
  There  exists for the different organs a scale of exten-
sibility, at the top of which  are  those which  have the
greatest  laxity in  the  arrangement of their fibres, as the
muscles, the  skin, and cellular substance ; at the bottom
of the scale  are those which  are  characterized  by their
density, as the bones,  the cartilages, the tendons, and the
nails.
  We must  not, however, be deceived  by appearances,
with regard to the extensibility of parts of the body ; for
the serous membranes, which at the first glance would
seem to  be capable of great  distension, do not yield so
much of themselves,  as from the development of their
folds.   Thus the  displacement of the skin, which aban-
dons certain  parts, while  it spreads over tumours in the
vicinity, might easily give rise to the supposition of its
being capable of a much  greater distension  than that of
which it is really  susceptible.
  With extensibility of texture, there  corresponds a cer-
tain mode of contractility, which  may be designated by
the name of  contractility  of texture.   This can only take
place after a previous  distension.
  In general the greater number of our organs are main-
tained in a certain degree of tension from different causes;
the locomotive muscles by their  antagonists, the hollow
muscles by the different substances which they enclose ;
the vessels by the fluids, which  circulate  within them,
the skin of a part by  that of  the  neighbouring parts, the
alveolar parietes  by  the  teeth which they contain.  If
these causes be removed, contraction  supervenes ; thus,
if a long muscle be cut, its antagonist will be shortened;
if a hollow  muscle be emptied,  it will contract;  if an 
PHYSIOLOGICAL RESEARCHES
artery be  deprived of  its blood, it will  become a  liga-
ment ; if the skin be cut into, the borders of the incision
will retire from each other; if a tooth be drawn, its cavity
will be obliterated.
   In these cases it is the cessation of the natural  exten-
sion, which occasions the contraction ; in other cases it is
the  cessation of an unnatural extension  which  does  so.
Thus, the  lower  belly is  straitened after puncture or
delivery;  the maxillary sinus, after  the  extirpation of a
fungus;  the  cellular texture,  after the opening of an
abscess, the tunica vaginalis,  after the operation of hydro-
cele, the skin of the scrotum, after the extirpation of the
voluminous  testicle, by which it was distended ; the sac
of an aneurism, after the evacuation of the fluid.
   This mode of contractility is not by any means depend-
ent on life; it belongs only to the texture, to the organic
arrangement of the part,* yet still receives from the vital
powers an increase of energy.   Thus the retraction of a
muscle, which is cut in the dead subject, is much smaller
than that of  a muscle divided  in the living  animal;  in
the  same  way,  the retraction  of  the skin  varies  ; but
though less  evident, this  contractility  subsists always,
and like its corresponding extensibility has no other limit
than that of the decomposition of the part.
  * When a patient dies after having for a long time been deprived of
solid and liquid  nourishment, it is not rare to find  in him the stomach
and intestines considerably lessened in their two dimensions, the internal
cavity almost entirely  effaced, the length being hardly a third of what
it was before the disease.  We truly say then with Bichat that is a
contraction  from a want  of extension.  But that this mode of con-
tractility is as he says  perfectly independent of life and owing only to
the arrangement of parts, is  what cannot be admitted.  If it were so
in fact, by emptying the stomach after death, we might  produce  a con-
traction similar to that which is produced during life.  Now experiment
shows us, that this does not take  place. The stomach when emptied
remains flaccid,  and does not contract in any perceptible degree. 
ON LIFE AND DEATH.
127
  The greater number of authors  have confounded the
phenomena of this contractility with those of the insensi-
ble organic  contractility, or tonicity.  Of these  I might
reckon Haller, Blumenbach,  Barthez and  others, who
have referred to the same principle the return upon them-
selves  of the abdominal  parietes, after distension, the
retraction of the  skin, or a divided  muscle, and the con-
traction  of  the dartos from  cold.   The  first  of  these
phenomena  is owing to the  contractility depending on
texture,  which does  not suppose  the  application  of an
irritating substance;  the  second,  to tonicity,  which is
never exercised excepting when influenced by such appli-
cation.
   Neither have  I myself, in my  treatise on  the  mem-
branes, sufficiently distinguished these  two modifications-
of contraction, but we evidently ought to establish  be-
tween them the most decided limits.
   An  example will render this  more  sensible.  Let us
take for  it  an organ, in which  there  may be observed
all the kinds of contractility, of which I have hitherto
spoken ; a voluntary muscle for instance: In distinguish-
ing the species with precision we may acquire a clear and
precise idea  of each of them.
   Now such  muscle may enter  into action first by the
influence of the nerves, which it receives from the  brain;
here it shews its animal contractility.  Secondly, it may
be brought into  action  by the stimulus of a physical or
chemical agent applied to it, a stimulus, which artificially
creates a motion,  analogous to that, which  is natural to
 the heart, and other involuntary  muscles ;—here we have
 the sensible organic contractility or irritability.  Thirdly,
 its action may be produced by the influx of fluids,  which
 penetrate all  its parts for the purpose of carrying thither
 the matter of nutrition, and which  at the same  time are 
128          PHYSIOLOGICAL RESEARCHES
the occasion of a partial  oscillatory  movement in each
fibre, in each molecule, a movement as necessary to the
function of nutrition, as in the glands it is  indispensable
to the process of secretion, or in the  lymphatics to that
of absorption.*   Such  action we refer to the insensible
organic contractility or tonicity : Fourthly, by the trans-
verse  section of the  substance or body of the muscle,
may be determined the retraction of its two ends towards
their points of insertion.  Here the contractility of its
texture is displayed.                           V
   Any one of  these  kinds of contractility may cease to
exist in a muscle  and  the others may not  be affected.
Cut  its nerves, and there will be  no longer any  animal
contractility ;  but  the two modifications of its  organic
contractility will continue  to subsist.   Impregnate  the
muscle with opium, suffer  its vessels to be well  pene-
trated with  this substance  and it  will cease to contract
under the impression  of stimuli,  it will lose its  irrita-
bility, but  it will continue to  possess  the tonic  move-
ments, which are occasioned  by the  influx of blood into
it.   Lastly,  kill the  animal, or rather  let it live, but tie
the vessels which go to the limb, and the muscle will in
such case lose its tonic power and possess its contractility
of texture only.  The latter will only cease on the super-
vention of sphacelus.
   By these examples the different kinds of contractility
may be appreciated with respect to  the organs where they
are assembled in a smaller number than in  the muscles of
volition; in the heart for  instance and in the intestines,

   * We know that the organs are nourished, that the glands secrete,
we know that certain vessels absorb (whether they be the lymphatics
or not,) but we do not know, that all this  is produced by a partial
oscillatory movement in each fibre, in  each molecule.  No one can be
certain that this movement takes place, because no one has seen it. 
ON LIFE AND DEATH.
129
where there exists a sensible and insensible contractility,
the organic being retrenched ; and again in the tendons,
aponeuroses, and bones, where the  animal  and sensible
organic contractilities are wanting, the insensible organic
and the contractility of texture only  remaining.
  In general  these two last are inherent in  every kind
of organ, the two first belonging  to some in particular
only;  hence  for the  general  character of  living  parts
we must choose  the  insensible organic contractility  or
tonicity,  and for  the  character  of  all  organized  parts
whatsoever,  whether living or dead, the contractility of
texture.*
   We shall farther remark, that this  last in the same way
as its corresponding extensibility  possesses them,  has its
different degrees, its scale  of intensity, the skin and the
cellular substance on the one hand, the  tendons, the apo-
neuroses, and the bones on the other, forming the extremes
of this scale.
   From all that has been said,  it is easy to perceive, that
in the contractility of every organ there are  two  things
to be considered, namely the contractility, or the faculty,
and the cause, which  puts it in action.  The contractility
is always  the same, belongs to the organ, is  inherent in
it, but the cause  which determines its exercise may be
various.

  * Why invent a new word, when we have that of elasticity, which
expresses for all bodies whether organic or inorganic, that tendency to
resume their usual form and size, when the cause that made them change
them is no longer in exercise ?
17 
130
PHYSIOLOGICAL RESEARCHES
VIII.  Recapitulation of the properties of living bodies.
   A recapitulation of these properties may be seen in the
following table :
      Classes.         Genera.          Species.      Varieties.
                                  ( 1st Animal
                   1st Sensibility—  <
                                    2d Organic
                                    1st Animal
                   2d Contractility— <J            ^ 1st Sensible
                                    2d Organic—
1st Vital-
                          jility—  )
                                  h

                  F                     -      ,
                  ^                           (2d Insensible
                  fist Extensibility
    2d of Texture— <
                  (2d Contractility
  I  have not inserted in this table that modification of
motion, which takes place in the iris, the corpora caver-
nosa, &c.  a motion, which  precedes  the influx  of  the
blood, and  which is not  in  such way occasioned, neither
have I  mentioned the  dilatation of  the  heart,* and  in a
word that species of active and vital excitability, of which
some parts appear to be susceptible, and  my reason  for
this neglect,  although I recognise the reality of the modi-
fication, is my want of clear and  precise ideas  on  the
subject.
   From the  properties, which I have now explained, are
derived all the  functions, all the phenomena, which are
exemplified  in  the  living  ceconomy.  There is not one,
which  may not be traced to them after  a strict analysis,

  * Bichat here unites three  sorts of motion which have no relation
between them; the systole of the cavities of the  heart  should be  con-
sidered as a really active dilatation.  The increase of size of the corpora
cavernosa, which is an effect purely passive of  the accumulation  of
blood in those parts, and which can be produced  after death  by artifi-
cially accelerating the circulation in them;  and  finally, the motion of
the iris, a motion evidently produced by a muscular contraction, excita-
ble by galvanism or pricking the nerve. 
ON  LIFE AND DEATH.
131
in the same manner as in the  phenomena of physics we
recur to the properties of attraction, elasticity, &c.
   Wherever the vital properties are in  action, there is a
disengagement, and a loss of caloric peculiar to the animal,
which compose  for him a temperature independent of the
medium  in which he lives.   The word caloricity  will
hardly serve for the expression of this fact, which  is a
general effect of the two great vital  powers in a state of
action, and not  produced by any especial faculty distinct
from  them.  We do not make use of the words, digesti-
bility, or respirability, because  digestion and respiration
are the results  of functions derived  from the  common
laws of the system.
   For the same reason  the digestive  power of  Grimaud
suggests an inaccurate idea.  The  assimilation of hetero-
geneous substances to our organs, is not the effect of any
peculiar power.   The same may be said of the  different
principles  admitted by a  number  of  authors, who have
attributed  to results and functions  denominations expres-
sive of laws, and  vital properties.
   The proper life of each organ is  composed of the differ-
ent modifications, to which are submitted in each of them
the vital sensibilities and mobilities, modifications, which
invariably are productive of others in the circulation and
temperature of  the  organ.  Let it be noticed  however,
that each  organ  independently of the  general sensibility,
mobility,  temperature, and circulation  of  the body, has
a particular mode of sensation and heat, together with a
capillary  circulation, which being withdrawn  from the
influence of the heart, receives the influence only of the
tonic action of the part.*   But  we may pass over a
   * Without denying the influence which  the  capillary systems of the
different organs have on the circulation, we have shown that even in
the veins the action of the heart is felt and modifies the course of the
blood. 
132
PHYSIOLOGICAL RESEARCHES
point so frequently  and sufficiently discussed  by other
authors.
   Let it here be understood that I offer what I  have said
on the subject of the vital powers, only as a simple view
of the different modifications, which they experience in
the two lives.   These detached ideas will in a short time
form the basis of a more extensive work.
   Neither have I recapitulated  the  different divisions of
the vital powers, which  have been adopted by authors;
the reader will  find them in their works, and will  easily
perceive the differences, which distinguish  them from
those, which I have  adopted.  I shall  only observe that
were  these  divisions clear and precise, did they suggest
to all the same meaning, we should  not have to  regret in
the writings of Haller, Lecat, Wyth, Haen, and all  the
physicians of Montpellier, a number  of disputes  of no
importance to the interest of science, and surely fatiguing
to the student.
                  CHAPTER VIII.

OF THE ORIGIN AND DEVELOPMENT OF THE ANIMAL LIFE.

  If there be any circumstance, which  establishes a real
line of demarcation between  the  two lives, this circum-
stance undoubtedly is the mode and epoch of their origin.
The organic life is active from the very first moment of
our existence; the  animal  life begins after birth only;
for without external excitants  the latter is  as necessarily
condemned to inaction, as without the fluids of the  ceco-
nomy,  which are its internal excitants, the  former would
become extinct.   But the subject, on which we are now 
ON LIFE AND DEATH.
133
engaged deserves a more particular discussion, and in the
first place let us examine, in what manner the animal life,
which for some  time is absolutely null, is born as it were
and developed.

I.  In the foetus the first order of the functions of the
          animal life is not as yet in action.

   The instant, at which the foetus begins to exist, is nearly
that of its conception  ; but this existence, the  sphere of
which  is  every day enlarged,  is not the same as that,
which  the child is destined to enjoy after birth.
   The state, in which the foetus exists while in the womb,
has been  compared to that  of a profound sleep.   Such
comparison is inexact.  In  a  state of sleep the animal
life is  only in part suspended.   In the  foetus it has  not
commenced.  We have seen in fact, that this life is made
up of the simultaneous or distinct exercise of the senses,
of the nerves, of the'brain, of  the organs of locomotion,
and the voice.  Now  in  these  different  functions every
thing in such  slate is inactive.
   Every  sensation supposes  the action of external  bodies
upon  our own, together with  the  perception of such
action ; a perception which  takes place by  virtue  of the
sensibility of the system,  which is either general or par-
ticular, for  the  tact is the faculty of perceiving general
impressions,  and  has  for its  object to warn us of  the
presence  of bodies, together  with their common  attri-
butes, such as heat, cold, dryness, or  humidity, hardness
or softness.   To perceive the particular modifications of
bodies is  the  business  of the senses.
   Has the foetus  in utero any  general sensations ?   To
decide this question, let us enquire whether any impres-
sions are capable there of exercising its tact.  The foetus 
134         PHYSIOLOGICAL RESEARCHES
 lives in a temperature at all times the same, swims in a
 fluid, and is thrown from time to time against the parietes
 of the womb : such are the  three sources of its general
 sensations.
  We shall now remark, that  the two former are next to
 nothing, and that the foetus cannot have a consciousness
 of the medium, in which it is nourished, nor of the heat,
 by which it is penetrated, for  every sensation supposes a
 comparison between an actual and a past  state  of being.
 We  are  sensible of cold, only because we have experi-
 enced an antecedent heat; were  the  temperature of the
 atmosphere invariable, we  should have no idea  whatever
 of temperature.  The  Laplander enjoys  himself  in  a
 climate,  which would be pain, and death to the  Negro, if
 suddenly transported thither.   It is not at the time of the
 solstices, but at that of the  equinoxes, that our sensations
 of heat,  and cold  are  the  most lively.  The  reason of
 which must be, that at the latter  seasons, their varieties
 are more numerous, and occasion more frequent compari-
 sons between that, which we feel and that which we have
 felt.
  What  we have now said of temperature, we may repeat
■with respect to the waters of the amnios : the foetus can-
 not  be sensible of their influence, because the  contact of
 any  other medium is unknown to it.  Before bathing,
 we are not sensible of the  air, after bathing, the impres-
 sion made by it upon us is  unpleasant.  It then affects us
 because there has been an interruption of its action  upon
^he cutaneous organ.
  Is the shock of the parietes of the  matrix a  more real
 cause of excitement,  than  the waters of the amnios, or
 temperature ?  At first we  might be  inclined  to  answer
 this question in the affirmative, because the foetus being
 only at  intervals  subject to such stimulus,  there should 
ON LIFE AND DEATH.
135
appear  to  result  from  thence a  sensation.   But let us
remark that the density* of the uterus in a state of preg-
nancy being  little  greater than  that of its  waters,  the
impression  must  be trifling.   In fact the more the con-
sistence of bodies resembles that of the medium in which
we live, the  less powerful will be their  action upon us.
Water  for  instance,  when reduced into vapour  in  our
common fogs, and mists, affects the tact but  slightly  ; in
proportion  as it is condensed it is the cause of a  livelier
affection.
   The air then, to the animal which breathes, is truly the
general comparative term, to  which he refers all the  sen-
sations of tact.   If the hand be plunged into carbonic
acid gas, such substance will not affect the tact because its
density is  little different from that of the air.
   The variety then of these sensations is in proportion to
the difference existing between the density of the  air, and
that of the bodies,  which are the occasion of such sensa-
tions.  In  the same  way, the measure of the sensation
of the  foetus  must be the excess of density in  the matrix
above that of its waters.   Now  such  excess being very
inconsiderable, the  sensation  of it must be very obtuse.
   This  assertion with  respect  to the foetus  will  become
more general if we add to it  the following :  namely, that
the mucous membranes, which are the seat of an inward
tact  have   not as yet begun  to exercise their functions.
These  membranes, after birth, being continually  in  con-
tact with extraneous  substances, possess  in these bodies

   * It is unfortunate that Bichat makes use of the word density,  as he
 seems to be ignorant of its true signification.
   The resistance, which  the womb offers to the  foetus that strikes
 against it, is wholly independent of  density, and results only from the
 greater or less flexibility of its parietes.  Cork is much less dense than
 mercury, and yet it offers to the finger, when pressed against it, a much
 greater resistance. 
13rj          PHYSIOLOGICAL RESEARCHES
so many causes of irritation,  which  being continually
repeated, become excitants  to  the organs : but  in  the
foetus there is no succession in these causes.  The same
urine, the same meconium,  the same mucus at all times
exercise  their action upon the bladder, the intestines, and
pituitary membrane.
  From  all this we may  conclude, that the general sen-
sations of the foetus  are  very  inconsiderable,  though  it
should appear that the child in this state is surrounded by
many of the causes, which are hereafter to beget sensations.
Neither are the particular sensations of the foetus more ac-
tive ; indeed they cannot be so for their causes are  absent.
  The eye which is  closed  by  the pupillary membrane,
and the nostrils,  which are scarcely indicated, would not
be capable of  receiving impressions, even in the supposi-
tion  that light and  odour could  act upon them.  Applied
against the palate, the tongue is in contact  with  nothing
capable of producing  savour.   Were it in  contact  with
the waters of the amnios, the effect would be the same,
because  as we have  said, there is no sensation, where
there is  no variety  of impression.  The  saliva  of one
person to another person possesses savour, to  the indi-
vidual himself it is insipid.
  The ear in  like manner is  awakened by no sound.   All
is calm,  every thing  reposes with  the little  individual.
  Here  then  we have proved,  that four of the gates of
sensation are  shut in  the  foetus  ; and let us now observe
that the  nullity of action in the  senses which we  have
mentioned,  must occasion  very nearly the same  nullity
with respect to that of the touch.*
  * Of these four sources of sensation,  the first, whatever Bichat may
say, exists in the foetus before  birth, and the other three, do not  exist
some hours after; the eye is insensible to light, the ear to sound, and
the taste  is not really in exercise when the first food creates in the
organ an unaccustomed sensation. 
ON LIFE AND DEATH.
137
   In fact, this  sense is  especially destined  to confirm the
notions which are  acquired  by the others,  and to rectify
them, for the latter are frequently illusory—the touch is
always the agent of truth.*   In  attributing to the touch
such  use, nature has submitted it directly to the  will;
light,  odours, and  sounds affect  their respective organs
independently  of the will.
   The exercise of the  other senses precedes that of the
touch, they are the occasion of it.  If a man were  born
without sight,  hearing, smell,  or  taste, can we conceive
in what way, he  would  be possessed of the sense of touch?
   The foetus resembles such a man ;  it possesses where-
withal to  exercise  the touch in  its hands, which are
already  developed,  and in  the parietes of  the  matrix.
Nevertheless  the  foetus is  never  in  action,  because in
seeing, in hearing, in  smelling,  and  in  tasting  nothing,
it is not  disposed  to exercise the  touch in  any way.  Its
members are little  better than what to  the  tree are  its

  * Philosophers and physiologists  accord to the touch  a great preemi-
nence over the other senses.   The senses of seeing, smelling and hear-
in0- are, say they, the sources of a thousand illusions.  The touch alone
is exempt  from them,  and even rectifies  the  errors which come from
elsewhere;  the touch  is the sense of  reason.  It  is  undoubtedly  a
delightful prerogative ;  but let us  see if it is incontestable.  And first
does the touch never deceive us ?  All children know an experiment
which proves the contrary.  If we cross two fingers of the same hand,
and place in the angular space between their extremities a small body
which touches both of them, the touch will give the sensation of two
distinct bodies.  It is then true that the touch may become a cause of
errors ; it no doubt serves to rectify those of the  other senses, but do
not these in their turn often defend us from the errors of the touch ?  If
the sio-ht were not  almost constantly in  exercise, the errors of touch
would be  much more  numerous; we can judge of them by what we
experience when  we are in the dark.  If we were  to take from one
man the use of his eyes, and from another that of his hands and the
 exercise of touch as much as possible, we should see which would be
the most embarrassed, which would make the most false judgments,
                18 
138          PHYSIOLOGICAL RESEARCHES
branches, which  do not transmit  the  impression of the
bodies, with which they are entangled.
  I shall here notice a  great difference between the tact
and the touch; they were formerly confounded by physi-
ologists; the impressions of the latter are always directed
by the will, those of the  former do  not depend on it.  We
shall  conclude that the  portion of the  animal life which
constitutes sensation, does not exist in  the foetus.
  This  nullity of action in  the senses supposes the same
deficiency of action in the nerves,  which belong to them,
and in that of the brain  from whence they issue ; for
the business  of  the former is  to transmit,  of the latter
to receive.  Now  without  objects for transmission  and
reception, the two functions cannot have place.
  From perception are  immediately  derived the memory
and imagination; from these the powers of the judgment
and the will. . All this series of faculties then  has not had
a beginning in the foetus, because  the  foetus has not per-
ceived, or had sensation.   The brain  exists in a state of
expectation, it possesses all that  is  requisite  for action.
It does not want excitability, but  stimulus.   The first
division of the animal life in consequence, or  that, which
relates to the action of exterior  bodies,  on the animal,
has scarcely  an  outline in  the foetus.   Let us examine
whether  the same be true of the  second division of the
animal life, or that which relates to the reaction of the liv-
ing body.

II.  Locomotion exists, but belongs in the foetus to the
                     organic life.

  When  we see  the  strict connexion  which exists in
animals, between  sensation and  their voluntary  efforts
we might be induced  to believe, that voluntary motion 
ON  LIFE AND DEATH.
139
increases or diminishes with the increase or diminution
of sentiment; for as sentiment furnishes out the materials
of the will, when  it does not exist, volition cannot exist:
from induction to induction, it might thus be  proved that
in the foetus the muscles must  be totally inactive.
  Nevertheless the foetus  moves, and  sometimes  even
very strong  shocks are the result of its  motions.   The
reason  why it does not produce  sound, is  because the
medium for the production of  sound is  wanting.   But
how can we ally the inertia of the first part of the animal
life with the activity of the second.  It is thus.
  We have  seen in speaking of the passions,  that the
muscles  of locomotion are  brought  into action in  two
manners.  1st,  by the will ; 2dly, by sympathy.  This
last mode of action occurs, when from the affection of an
inward organ the  brain is  affected also, and  occasions a
motion which, in such case, is involuntary.  A passion, for
instance,  affects the liver, the liver the brain, the  brain
the voluntary  muscles.  Here  it  is the liver, not the
brain,  which is  the principle of  motion :  so  that the
muscles, though always thrown into  action, immediately
from the irradiations of the brain, belong nevertheless, as
to their  functions,  sometimes  to the  one life, sometimes
to the  other.
  Hence it  is  easy to conceive in what  way the foetus
moves :  witli the. foetus,  locomotion  is  not a portion of
the animal life  ; its exercise does not suppose a pre-exis-
tent will;  it is purely  a sympathetic  effect.
  In  utero the phenomena of  the organic  life succeed
each other with an extreme rapidity ; a thousand  differ-
ent motions are incessantly connected  in the organs of
circulation and nutrition.   In these, every thing is ener-
getically in action.   But this activity of the  organic life
supposes a frequent influence exerted upon the brain by 
140         PHYSIOLOGICAL RESEARCHES
the inward organs, and  consequently  as many  reactions
on the part of the brain by sympathy upon the muscles.
Besides, the  brain is at such time more susceptible of
such sort of influence, being much more developed than
the other  organs, and entirely passive on the side of the
sensations.
  We may now conceive what  the  motions or the foetus
are.   They belong to the same class as many of those
of the  adult, which have  not  been  as  yet sufficiently
distinguished.  They are the same as  those  which are
produced in the voluntary muscles by  the passions ; they
resemble those of the  man who  sleeps, and who moves
without dreaming,  for nothing  is  more  common than
violent  agitation  in sleep succeeding difficult digestion.
The stomach is in strong action; it ac.ts upon the brain;
the brain upon the muscles.
  I might find a number of other involuntary  organic
motions taking place in the voluntary muscles  of the
adult, and  consequently adducible to my present purpose;
but what I have said on this subject will suffice.  Let us
remark  only, that the  organic motions, as well as the
sympathetic  affection of the  brain, which is  the seat of
them, must gradually dispose this organ, and the muscles
of the foetus,  the one to  the perception of sensations, and
the other  to the motions of the animal life,  which are to
commence after birth.   But on this head I shall refer to
the memoirs  of Monsieur Cabanis.
  From what has been said, then, I believe we may con-
fidently assert, that  in the foetus  the animal life does not
exist, and that all the actions  which take place  at  this
age, depend upon the  organic  life.   The foetus,  indeed,
has nothing of the especial character of the animal.  Its
very existence is that of the vegetable ;  and its destruc-
tion can only be said to be that of a living body, not of an 
ON LIFE AND DEATH.
141
animated being.  Thus, in the cruel alternative of sacri-
ficing the life of the mother,  or  that of the child,  the
choice cannot be doubtful.
  The crime of destroying a  fellow-creature  is  much
more relative to his  animal, than to his organic life.—
We regret the being  who feels, who reflects, who wills,
who acts accordingly, and not  the being which  breathes,
which is nourished, which is the seat of the circulation
and the secretions.  It is the former, whose violent death
is accompanied with those images of horror, under which
we look on homicide.   In proportion then as in the series
of animals, their intellectual functions diminish,  is dimin-
ished also the painful  sentiment which we feel at sight of
their destruction.
  If the blow, which terminates by an assassination  the
life of a man, were to destroy his organic  life only,  and
suffer the other to  subsist without alteration, such blow
would be regarded with indifference, would excite neither
pity for the victim, nor horror against the aggressor.

III.  Development of the animal life, education of its
                       organs.

  A new mode of existence  commences for the  infant
after birth; a variety of functions are added to its organic
life;  their aggregate become  more  complicated ; their
results are multiplied.   As for the animal  life, it only
begins;  and at this  period a number  of  relations  are
established between the  little  individual and what sur-
rounds him.   It  is then that every thing assumes with
him  a different mode of being, but at  this remarkable
epoch of the two lives, where the one is augmented by
almost the half, and where  the other commences  only,
they take  upon them  both a distinct character, and  the 
142
PHYSIOLOGICAL RESEARCHES
aggrandisement of the first by no means follows the same
laws as the development of the  second.
   We shall soon remark, that the  organs of the internal
life attain  at  once  their perfection,  and that from the
instant at which they begin to act,  they act  vvith  as much
precision  as they ever will  do.   On  the  contrary, the
organs of the external  life require a species of education;
they arrive  only by degrees at  the perfection which we
afterwards see in them.  This important difference should
be thoroughly examined.  Let  us  begin by appreciating
of what the animal  life at first consists.
  In examining the different functions of this life,  which
start at once  into  existence, we  shall observe  in  their
development a slow and graduated progress.—We shall
see, that it is insensibly and by  means of a real education
that the organs attain a precision of action.
  The sensations are at first confused ; they transmit only
general images ; the eye has only the sensation of light;
the ear that of sound only ; the nose  only  that of smell.
As yet there  is  nothing distinct  in these general affec-
tions of the senses; but from habit the strength  of the
first impression is lessened  and  the particular sensations
take  place.   The  great differences of colours, sounds,
smells,  and savours, become perceptible ;  by little and
little their secondary differences also are perceived, and
after a certain lapse of time  the  child has learnt to see, to
hear, to smell,  to taste, and to touch.
  After successfully  undergoing  the  operation  for the
cataract, the patient,  who  has  previously  been totally
blind, is sensible of light only, and learns  by gradation
to distinguish  the objects which reflect it.   Another per-
son,  before  whom, as I have said, for the  first time  is
exhibited the magnificent  spectacle of an  opera,  at the
first  glance, perceives  only a whole, which delights him, 
ON LIFE AND DEATH.
143
and only  by degrees is able to isolate the enjoyments of
which the dance, the music, and the decorations are pro-
ductive.
  The  education  of the  brain is  similar to  that of the
senses.   Whatever depends upon its action, acquires the
perfection, to which it is destined, by degrees only.  The
powers of  perception,  memory and imagination, which
are all  of them preceded  and occasioned  by the  sensa-
tions, increase and  extend in  proportion  as by repeated
excitement they are  brought  into  exercise.—The judg-
ment, of  which  they form the triple base,  associates but
irregularly  at first its motions, which themselves are but
irregular.   In  a short  time a greater degree of perspi-
cuity is observed in its operations, and lastly they become
precise and rigorous.
  The voice and the agents of locomotion- exemplify the
same phenomenon : the  cries of young animals  at  first
are only an  unformed  sound, which possesses no sort of
character :  by age they are gradually modified, and after
long  repeated exercise  affect  the peculiar consonances of
the species,  by which, and particularly during the season
of their loves, the individual of the same species is never
deceived.*   I do not instance the speech of man, for this
is evidently the fruit of education.
  In examining the newly born animal, its muscles will
be seen continually in action.  As every thing is new to
it, every  thing is an excitant to it,  and makes it move; it
  * This assertion is not correct, and the voice, at the earliest age, has
consonances peculiar, not only to the species, but even to the indi-
vidual.   The  man accustomed to the very striking differences of the
articulate sounds of speech or the distinct sounds of music, distinguishes
niih  difficult}' the differences in cries; but the animals to whom  the
cry is the habitual medium of expression are not deceived in the same
way ; the ewe, in the midst of a whole flock, distinguishes the voice of
her lamb, and this soon learns to recognize the voice of its mother, 
144          PHYSIOLOGICAL RESEARCHES
endeavours to touch every thing, but neither progression,
nor the power of standing can have place when the con-
tractions of the voluntary muscles  are  so numerous.   It
is  necessary for  such, that habit shall have  taught it
to  combine particular contractions with other particular
contractions ;  until then  it  stumbles and falls at every
moment.
  Undoubtedly the inclination of the pelvis in the foetus,
the disposition of the femora, and  the want of curvature
in  the spine, adapt  it  but  little for  standing immediately
after birth ; but vvith these causes is certainly also com-
bined the want of  exercise.*   Who does not know, that
if a limb be  suffered  to remain immoveable for a length
of time, it  loses  the habit  of  moving, and  that when
afterwards  its service is required, it requires a new kind
of education before it can  exercise its movements with
any regularity or  precision.   The man, who  for a  long
time should  condemn himself to  silence, would  experi-
ence in like manner  the  same embarrassment in his first
attempt at  utterence.
  From these considerations we may  conclude  that  our
exterior life,  to allow myself the expression, is learnt,
and requires before it can be perfected, a sort of appren-
ticeship.

IV. Of the influence of society  over  the  education of
             the organs of the animal life.

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

  * The locomotive organs do not require  a long education; as we see
in animals whose organization, at the moment of birth, is no obstacle
to motion.  A young  kid in an hour after, will stand on its legs, and
 before the end of the day we often see it skipping.  The partridge runs
 as it comes out of the shell. 
ON LIFE AND DEATH.
143
ence;  it enlarges the sphere of action of some of them,
lessens it for others, and modifies it in them all.
  I shall first remark, that it constantly gives to some
of the organs a perfection greater  than  naturally should
be their  portion.   Such in fact is the  nature of our occu-
pations as always to require the especial action of some
one, or other of these organs.   The ear  of the musician,
the palate of  the cook, the  brain of the  philosopher, the
muscles  of the  dancer, and  the larynx of the  singer,
receive in addition  to the general education of the exte-
rior life, a particular education.
   Under these considerations,  the occupations of man-
kind  might  be divided  into  three  classes.   The first
would comprehend all those, which especially regard the
senses, such as painting, music, and sculpture, the acts  of
the  perfumer and  the cook,  and in a word all those the
results of tvhich are productive of pleasure to the senses.
In the second would be ranged the occupations,  wherein
the brain  is chiefly called  into  action;  such as poetry,
the sciences of nomenclature, the mathematics and meta-
physics.   The occupations of dancing, equitation, and the
mechanic acts would form the third class.*
   Each several occupation  then of the individual, brings
 into  permanent activity, some  one organ in  particular,
 and gives it a peculiar perfection.   The  ear of the musi-
 cian in a piece of harmony, and the eye of the painter in
 a picture, distinguish many things  which entirely escape
 the vulgar.  It. frequently  happens that  this perfection of
   * The idea of classifying human occupations, according as they bring
 in play the organs of the senses, the intellect or  locomotion, is a wild
 and useless one.  This division besides is made  in a way altogether
 defective, since in the first class it is the result of the occupations which
 put in play the  organs, whatever may be  the means of execution ; in
 the second it is  the occupation itself, whatever may be the results, and
 in the third, it is at the same time the execution and the result.
               19 
146          PHYSIOLOGICAL RESEARCHES

action, is accompanied in the  more exercised  organ with
an excess of nutrition :  this we  may frequently observe
in the muscles of the  arm of the baker, in those of the
inferior limbs of the dancer, and in those of the counte-
nance of the  player.
  In the second place I have asserted that society con-
tracts the sphere of action, which should naturally belong
to many of the  external organs.  Indeed, for. the sole
reason that any one of  them  is  the more  occupied, the
others must be less so, and lose in aptitude what is gai.ied
by the single organ.   The most common observation will
prove this truth at every moment.
  Examine the philosopher, who in  his abstract medita-
tions, and in the silence of the closet condemns to inaction
his external and locomotive  powers.   Examine him by
chance attempting any exercise of the body, and you will
laugh at his awkwardness  and  air of constraint; his
sublime conceptions astonish, the heaviness of his  move-
ments is amusing.
  Examine on the contrary the dancer, who by the light-
ness of his steps exhibits apparently to the  eye whatever
the graces of fable have set  before  the imagination.  It
might  be imagined perhaps that  the profoundest medita-
tions, have been  productive  of such  felicity of motion ;
but let him be conversed with, and nothing very surpris-
ing will be found in the man.
  The observing mind,  which analyses the different indi-
viduals of society at every moment, will be led to similar
remarks.   Perfection  of action in the locomotive organs,
concurring with a like perfection of intellect, will seldom
be found. 
ON LIFE AND DEATH.
147
V.  Of the laws, which regulate the education of the
              organs of the animal life.

  It is manifest then that society inverts the natural order
of education  in  the animal  life, and that it irregularly
distributes to the different organs of this life, a perfection
which they would  otherwise enjoy in a more  uniform
proportion.
  A  determined sum of power, has been attributed to
every individual, which  sum  must  always  remain the
same, whether  it be equally or unequally  distributed,
accordingly the  activity of one  organ must imply  more
or less inactivity in the others.
  This truth will conduct us to the fundamental princi-
ples  of all  social education  whatever;  namely, that no
individual at the same  time, should be applied  to many
studies,  even if  it  be wished that  he should  succeed in
all  of them.   Philosophers have long insisted upon this
maxim, but I doubt whether the moral reasons on which
they have founded  it, are  all  of  them together worth this
single and beautiful physiological observation by which it
is demonstrated, that for  the purpose of augmenting  the
powers of one organ, there are no other means than those
of diminishing the powers of the others.   On this account
I shall dwell upon  this observation, and prove  its truth
by a variety of facts.
   The ear, and especially the touch, acquire in the blind
man, a perfection which would hardly be credited, were
not  its  reality  proved  by daily observation.  The deaf
 and dumb possess in the eye an accuracy of  sight, which
 is unknown to  those, with whom the powers of the  ear
 and  utterance are  unfolded.  Little connexion  with  ex-
 ternal  objects,  enfeebles the senses of persons  whe  are 
145         PHYSIOLOGICAL RESEARCHES
 subject to ecstasy, but gives the brain a power of con-
 templation, such as to make it appear, that  every part of
 the animal life, excepting that organ, during such affec-
 tion is in a state of sleep.
   But what occasion  is there for seeking in extraordinary
 facts, the proof of  a law which the animal in its healthy
 state exemplifies at every moment.  Let us consider in
 the series of animals the relative perfection of each organ,
 and it will be  seen at once, that  where any one of them
 is excellent, the others are less perfect.  The eagle, which
 has a very piercing sight, has  but a very obtuse sense of
 smell; in the dog,  the latter sense is extremely fine, the
 former dull.  The  sense of hearing is  particularly acute
 in the hare, that of touch in the  bat; the cerebral action
 predominates  in the  monkey, and vigour of motion in
 the ferae.
   Every species then possesses some particular division
 of its animal  life, in  a  degree of excellence superior to
 that of the others.  Not a single instance will be found,
 where the  perfection  of one organ does not appear to be
 acquired  at  the expense of the others.  Man in general,
 abstraction being made of every  other consideration, has
 the ear particularly good, and in the  natural order of
 things, this  must be so; because  his speech, which exer-
 cises  the  ear  incessantly, is for  this organ a permanent
 cause of activity, and therefore of perfection.  And not
 only in the animal life  is  this law  remarkable ; but it
 appears to  have place also, in all the phenomena of the
 organic life.  The morbid affection of one of the kidneys,
of one of the parotid  glands, will double the secretion of
the other.
  Let us  now  examine what happens in the process of
digestion.  Each system  at such time  is the seat of an
exaltation of the vital powers.  Immediately after  the 
ON LIFE AND DEATH.
149
entry of the aliments into  the stomach, the action of all
the gastric viscera is augmented, the powers of life are
concentrated  about,  the epigastrium, and  abandon  the
organs of the external life; from thence arise, as authors
have  observed, the lassitude, the inaptitude of the senses
to the reception of external impressions, the tendency of
the individual to sleep, and the cold which is so frequently
felt in the integuments.
   The  gastric digestion being  completed,  the vascular
succeeds, and the chyle  is introduced into the circulatory
torrent, for the purpose of undergoing the influence of this
system,  and  that  of respiration  ;  accordingly the blood-
vessels and lungs  become  in  their turn, the focus of an
increased  action, the pulse rises, and the movements of
the thorax are precipitated.*
   It is then the glandular, then the nutrive system which
enjoy a marked superiority  in  the  state of  their vital
powers.   Lastly,  when  these  powers have been succes-
sively developed, over all  the system, they  return to the
organs of the  animal life, the senses resume their activity,

  * We know that at a certain period of digestion the pulse rises and
respiration is  accelerated ; we know it, I say, but we do  not know
the immediate  causes  of the phenomenon.  Is  it a  reason, in fact,
because a little chyle enters the lacteal vessels that the heart should
accelerate the course of the blood in a system of vessels entirely distinct
from these ?  Because afterwards this chyle, mixed in a small proportion
with the venous blood, goes with it through the lungs, is it a reason that
the motions of the lungs  should be  accelerated?  Undoubtedly not;
besides, the acceleration is not successive in these two functions, as
Bichat seems to imply.  The one is the necessary and immediate con-
sequence of the other.  But  why does the action of the heart increase
in this second period of digestion ?  We cannot tell; nor  do we know
why it diminishes in the first; for to think of explaining it by saying
that the vital forces are then concentrated at the  epigastric region, is a
mere illusion ; it is only changing the expression of the phenomenon.
and clothing it in a hypothetical form. 
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PHYSIOLOGICAL RESEARCHES
 the functions of the brain their energy, the muscles their
 vigour.  Whoever reflects upon what he has experienced
 after a somewhat copious repast, will be easily convinced
 of the truth of these remarks.
  In  this way,  the whole of the functions  represent a
 species of  circle, of which the  one half belongs to the
 organic, the other to  the animal life, the vital  powers
 seem  successively to traverse these two  halves.  When
 they are found  in one half, the other  is proportionably
 deprived of them, nearly in  the  same manner as every
 thing appears to languish  and be reanimated in  the two
 portions of the globe,  accordingly as the sun  refuses, or
 sheds down his beneficent influence.
  Should any  farther proof be required of this inequality
 of distribution with  regard to the vital powers, we may
find  it  in  the process  of nutrition.  This  process has
 always  an  excess  of action  in some one of the  organs,
 which  at such time may be  said to live more than the
 others do.   In the foetus, the brain and  the  nerves, the
 inferior members after  birth,  and at the  age  of puberty,
 the genital parts  and breast appear to grow at the expense
 of the others.
  From such a variety of considerations, we may estab-
lish the following to be a fundamental law of the distribu-
tion.of the  vital  powers, namely, that when they increase
 in one part, they decrease in  the rest of the living oecon-
omy, that the sum of them can never be  augmented, and
that they only transfer  themselves successively from one
organ to another.  By  the help of these  general  data, it
is easy to perceive why we cannot at the same time attain
to perfection in the various parts of our animal life, why
 we cannot at the same time excel in all the sciences.
  Universality of knowledge in the same individual is a
chimera; it is repugnant to the laws of our organization, 
ON LIFE AND DEATH.
151
and if history afford us some few instances of extraordi-
nary men, who have  thrown an  equal light upon  manv
of the sciences, such instances are but so many exceptions
to the common laws of nature ;  for who are we, that we
should venture on the  pursuit of many things at once, and
hope  to attain in all of them a perfection, which for the
most part, even when we  have but a single object in view,
escapes us ?
   v\ ere we capable of following at once a number of
occupations, such occupations would be those which have
the greatest  analogy among themselves with respect to the
organs which they bring into exercise :  and by restrain-
ing ourselves in this way within  a narrow circle, we may,
indeed, with a greater degree of facility  excel in many
parts ; but even here  the great  secret of  being superior
in any one of them, is that of possessing but a mediocrity
in the others.
   Let us  take, for example, the  sciences,  which bring
into action  the  functions of the brain.    We have seen
that these  functions  relate especially to the  memory,
which presides over  nomenclature; to  the  imagination,
under the empire of which, is poetry ;  to the attention,
which is chiefly excited by the details of calculation; and
to the judgment, whose dominion embraces the  whole
of the sciences of reasoning.  Now it  is manifest from
daily  observation, that not one of these different  opera-
tions  of the mind is to be developed but  at the expense
of the others.
   The habits of reciting  the  beauties  of Corneille  or
Racine, we might  naturally suppose would  enlarge the
mind of the actor;  what can be the reason that from such
habit  he does not acquire an energy of conception beyond
that of the vulgar?  The reason depends in part, no doubt,
upon  the  natural disposition of the man, but at the same 
152          PHYSIOLOGICAL RESEARCHES
time may be deduced from the greater efforts of memory,
and the faculty of imitation, which such a person is oblig-
ed to exert: for the purpose of enriching these, the other
parts of the brain are in a manner plundered.
  Accordingly, when I  perceive an  individual, desirous
at the same time of excelling by address of hand, in the
operations of surgery, by depth of judgment in the prac-
tice of medicine, by extent of memory in botany,  and
by  force  of attention  in  metaphysical contemplation,
methinks I see a physician, who, for healing a disease, for
the purpose of expelling, according to the old expression,
the morbific  humour,  at the  same  time  undertakes to
augment  the whole of the secretions  by  the simultaneous
use of sialagogues,  diuretics,  sudorifics, emmenagogues,
&c. &c.
  But  would  not the slightest acquaintance with the laws
of the  economy, suffice for hinting to  such  physician,
that one  gland pours forth  a  greater quantity of fluid,
only because the others secrete a less ?  Should  he not
know  that such a  variety of  medicines can  operate in
no  decided way, and  that  to exact too  much of  nature,
is frequently the means  of obtaining nothing?  The same
may be asked of the individual who  is desirous of simul-
taneous perfection, both in  the bodily and mental exer-
cises, who should pretend  to double  or triple his relative
life, when nature has willed that he should only have the
power of detaching from  some few  of his organs, some
few degrees of force, which may be added to one or more
of his  other  organs, and by no means that of increasing
the sum  of these powers.
   Do  we wish  that any  one organ in particular  shall
attain  to perfection,  we  must condemn the others to
inaction.  We castrate men to change their voices; it is
astonishing  that the barbarous idea of depriving them 
ON LIFE  AND DEATH.
153
of sight has  not  been found out also for the purpose of
rendering them musicians,  since it is well known how
acute the sense of hearing  is in the  blind.  Thz child,
who should  be destined to music, ceteris paribus, would
make a  much more  rapid progress, were  his ears to be
assailed by  harmonious  sounds only, and  every thing
removed which might be capable of exercising his other
senses.
   It is a truth, then, that our superiority in such or such
an art and science, may almost always  be measured by
our  inferiority in other  respects ; and that this  general
maxim which the greater number of the ancient philoso-
phers have  insisted on,  but which  many of  our modern
ones would  willingly overturn, has for its foundation  one
of the great  laws of the animal economy, and will ever
be as immutable as  the base on which it  rests.


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

   The education  of the organs of the animal life, is pro-
longed  for  a time which we cannot determine, as  it is
influenced by such  a  variety of circumstances ;  but  the
peculiarity of this education consists in its being the busi-
ness of each age, to bring to perfection certain organs in
particular.
   In childhood, the senses more especially are educated;
every thing seems  to  relate to the development of their
functions.   Environed with  bodies  which  are  new to
him, the little individual seeks to know them  all ; he
maintains in a sort of perpetual  expectation those organs
by which  his connexions  with what  is  near  him  are
established,  and undoubtedly his sensibility is excessively
developed.    His nervous compared  with his muscular
              20 
154
PHYSIOLOGICAL RESEARCHES
 system,  is proportionally very great; accordingly for the
 dissection of the nerves, we always prefer  the bodies of
 ehildren.
   With the education of the senses, the  improvement of
 the functions of the brain which relate to sensation is
 necessarily connected.   In proportion, then, as the  sum
 of the  sensations becomes enlarged, the  memory and
 imagination  begin to come into play.   The  age which
 follows infancy, is that of the education of those parts of
 the brain in which these faculties are seated.—It is then,
 that there have existed a sufficient number of  antecedent
 sensations  for the exercise of the memory, and for  the
 discovery of the type of those illusory sensations which
 it is the business of the imagination to assemble.  On the
 other hand,  the little  activity  of the judgment at  this
 epoch  is much  in favour  of the energy  of  these  two
 faculties ; and then the revolution which puberty brings
 on, the taste  which it develops, and the  desires which it
 creates, contribute very much to extend the sphere of the
 latter of  them.
   When perception,  memory, and the imagination have
 been perfected, when their education is  finished, that of
 the judgment commences, or rather becomes more active,
 for the judgment begins to be  exercised upon the very
 first materials, with which it is presented.  At this epoch
 the functions of the  senses, and partly those of the brain
 have nothing more to acquire, and all the powers of  the
 individual, are  concentrated upon the education of  the
judgment.
   Hence it is manifest, that the first portion of the animal
 life, or that  by means of which we are acted  on from
 without, and reflect  such  action, has at  each  age a divi-
 sion, which is then particularly unfolded.  The first  age
 is that of the education of the senses, the second that of 
ON LIFE AND DEATH.
155
the enlargement of the imagination, the third that of the
development of  the judgment.
  We should never then  prescribe the study  of the
sciences, which  exact the exercise of the judgment, at an
age when the senses are especially  in action ; but follow
in our  artificial methods of  education, the same laws
which preside over  the natural education of the organs.
The  child should be applied to music and design ; the
adolescent, to the sciences of nomenclature, and the belles
lettres;  the adult,  to the exacter sciences, where facts are
connected by a  process of reasoning.  The study of logic
and the mathematics, terminated our ancient plan of edu-
cation ; it was one advantage at least among its numerous
imperfections.
   As to the  second  portion of the  animal life, or that by
means of which the animal reacts upon  external bodies,
the state  of infancy is characterized by the number, the
frequency,  and  feebleness of its motions ;  adult age by
their vigour ; and adolescence by a mixture of the two.
The voice, however, does not appear to follow these pro-
portions, but is subject to an  influence which proceeds
especially from  the  organs of generation.
   I  shall not  dwell upon the different modifications,
which  with respect to the animal  life  are  derived  from
sex, climate, and season.   So many have treated of these
questions, that  it would  be difficult to  add to what has
been said upon  them.
   In speaking of the laws of education, as they affect the
 organs  of the external life, I have  supposed these organs
to  be in a  state of  complete  integrity, and possessed of
 whatever is necessary to their perfection.—If they  be
feeble or delicate, if any defect of conformation exist in
 them, these  laws will  only be applicable  more or less;
 for it is manifest  that the habit of judging will not rectify 
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PHYSIOLOGICAL RESEARCHES
the judgment, if the brain be badly constituted ; and that
the frequent exercise of the larynx and voluntary muscles,
will  never make  up for  the  irregularity of action occa-
sioned by irregularity of conformation.
                   CHAPTER  IX.

OF THE ORIGIN AND DEVELOPMENT OF THE ORGANIC LIFE.

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

   I. Of the mode of the organic life in the foetus.

  Nevertheless, the organic life of the foetus, is not the
same as that which the adult is destined to  enjoy.  Let
us enquire into the reason of this difference.
  We have said that the organic  life is the result of two
great orders of functions, of those namely of assimilation
and  decomposition, so as to  form an habitual  circle of
creation  and destruction.  Now  in the foetus this  circle
is singularly contracted. 
ON LIFE AND DEATH.
157
   For in  the first place, the functions of assimilation are
much fewer in  number; the molecules before they arrive
within the  organs which they are destined to create, are
not  submitted  to so  many  actions ;  they penetrate the
foetus  already  elaborated  by the  digestion,  circulation,
and  respiration of the mother.   Instead  of traversing the
apparatus of the digestive organs, which at this age appear
to be almost inactive, they enter at once into the system
of the circulation ; the  road which they  have travelled is
less, it is  not requisite  that  they should  be  presented  to
the  influence of respiration ; and accordingly the  foetus
of the mammalia has  in its preliminary organization a
near analogy with that  of the adult reptile, in which but
a small part of the blood at its  issuing from  the heart, is
sent into the vessels of the lungs.*

  * I am persuaded that the still very obscure theory of the foetus might
be elucidated  by that of animals who have a similar organization.   For
example, in the frog, in whom but little blood goes through  the lungs,
the heart is  a simple organ, with a single  auricle  and ventricle ; there
is a  communication or rather  continuity between  the two systems,
venous and  arterial, whilst in the mammalia, the vessels in which  the
red blood circulates do not  communicate with those which carry the
black blood, except it be by  the capillaries.
  In the foetus, the foramen ovale and the ductus  arteriosus also render
very evidently the arteries and veins continuous; in the foetus the heart
is likewise a simple  organ, not forming, notwithstanding its partitions,
but one cavity whilst it is  double after birth.  The two kinds of blood
mix at this period, as in reptiles.  Now, I shall prove hereafter, that in
the child who has  breathed,  this mixture would soon be fatal; that the
black  blood,  circulating in  the  arteries, would very quickly produce
asphyxia in  the animal.  Whence arises then this difference ?  It cannot
be studied in the fetus ; it is necess;iry perhaps to search for it in frogs,
salamanders and other reptiles, xfhich can, by (heir organization, be a
long time deprived of air without  dying;, a phenomenon which approxi-
mates them to the mammalia while living in the womb of the mother.
Till these very important researches are made, the. history of respiration
will be incomplete. 
158          PHYSIOLOGICAL RESEARCHES
   The molecules of nourishment in this way pass almost
 directly  from the circulating torrent into the nutritive
 system.   The  general process of assimilation, then,  is
 much less complicated than that of the following  age.
   On the other hand, those functions which  habitually
decompose the  organs, which  clear the system  of  sub-
stances already become injurious and foreign to its nature,
are at this age but very inactive.  Neither the pulmonary
exhalation, nor  sweating, nor  transpiration have as yet
commenced : the bile, urine, and saliva are  but small  in
quantity, if compared with what  they are  destined at a
future time to be, so that the portion of blood from which
they are to be- made in the adult, in the foetus is almost
entirely expended on the system of the nutritive  organs.
   The organic system of the foetus, then, is remarkable—
on the  one hand,  for the  extreme  promptitude of its
assimilation, a promptitude depending on  the very small
number of the  functions concurring to that end ; and on
the other, for the extreme inertia of its  decomposition,
an inertia depending on the little activity of the different
functions, which are the agents of this great process.
   It is easy from the foregoing considerations to  account
for the  rapidity which characterizes the  growth of the
foetus ; a rapidity which is manifestly out of all  propor-
tion with that which takes place at any other age.  In-
deed, while every thing is in favour of the progression  of
the nutritive matter towards the parts where it is destined
to be put down, every thing at the same  time seems  to
oblige  such matter  to remain  in the place  where it has
been deposited, the emunctories  of the system being
wanting.
   To the great simplicity of assimilation  in the foetus,
we may  add the great activity of the organs which  con-
tribute  to it an  activity, which depends upon the  more 
ON LIFE AND DEATH.
159
eonsiderable sum of vital power which they then partake.
All the powers of the economy,  indeed, appear to be
concentrated upon the system of the circulation and nutri-
tion; the functions of digestion, respiration, secretion and
exhalation, are exercised but obscurely.*
  If we now observe that the organs of  the  animal  life,
which are condemned  to a necessary inaction, are the seat
at the same time of a very small   portion only of vital
power (the surplus of this being thrown upon the organic
life) it will  be easy to perceive, that almost the  whole of
the powers which are afterwards to be developed  upon the
two systems in  general, will be then concentrated upon
those  which  serve to nourish and compose the different
parts of the foetus, and that in consequence the  functions
which concur to the process of nutrition and growth, must
at that age be the seat of an extreme energy.

    II. Development of the organic life after birth.

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

  *This explanation is no doubt  ingenious, but it  is  insufficient,  since
the causes which Bichat assigns for the rapidity of the growth of the
fetus cease entirely at the moment of birth, and yet the growth con-
tinues for a long time after to be as rapid. 
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PHYSIOLOGICAL RESEARCHES
long habitude.   A rapid glance upon  the development of
this life, will  be sufficient to convince us of the truth of
the above observation.
   At the instant of birth, digestion and respiration, vvith
a great part of the exhalations and absorptions commence.
Now after the first inspirations and expirations ;  after the
elaboration  in the  stomach  of the first milk, which is
taken  in by the  infant, as  soon as the exhalants of the
lungs and the skin have once rejected  some small portions
of their  respective  fluids, the  respiratory,  the digestive
and exhalant organs, have as perfect an action as they ever
will have.
  At the same time all the glands, which slept as it were,
which poured forth but a very small quantity of fluid, are
awakened from their torpor by the stimuli  of the various
substances which are applied to the mouths of their excre-
tory ducts.   The passage of the milk at  the extremities
of the stenonian  and wartonian ducts, of the chyme at the
end of the choledochus and  the pancreatic  duct,  the con-
tact of air with  the orifice  of the urethra, awaken  into
action  the salivary glands, the pancreas, the liver, and the
kidneys.  The air in  like manner upon the inner surface
of the trachea and  the nostrils, and  the  aliments upon
that of the digestive  passages, are the excitants  which
rouse these parts into action.*

  * When two phenomena are seen to follow each other immediately,
we are naturally led to consider one as the cause of the other.  Post
hoc ergo propter  hoc.  It is a form of reasoning which is very often
abused.  Food taken into the mouth touches the orifice of the  salivary
ducts, the  fluid flows out, and it is then  concluded  that the  salivary
gland has been excited by the impression made on the extremity of its
canal.   At the moment of birth, the orifice of the urethra is exposed
to the contact of the air, and soon the kidneys begin to secrete;  then
it is the impression  of the air on the urethra that has  produced  their
action.  But is not this contact of the food in the one case, and of the 
ON  LIFE AND DEATH.
161
  It is then also that begin the various excretions of the
system :  now if  we examine well  the  different organs
which concur to  the above  mentioned  phenomena, we
shall find that they require no sort of education.
  I shall not inquire into  the reason of this difference in
the development of the two  lives.   I  shall only observe
that it  is  out of the power of any  one  of the  inward
organs, to acquire a marked  degree of superiority over
any other, for the same reason that they all of them attain,
immediately upon entering into action, as great a perfec-
tion as at any time they are destined to possess.
  Nevertheless there is nothing  more common  than the
predominance of one system of the organic life  over the
other systems; this is sometimes the vascular, sometimes
the pulmonary apparatus, at other times the organs of
digestion, and the liver especially, have the greater degree
of development, and decide on  the particular tempera-
ment of the  individual ;  but  the  cause  of this sort of
constitution  depends  on  primitive  organization, on the
structure of the parts, on their conformation.   Such supe-
riority is by no means the effect  of exercise or habit, for
the foetus and the child display the same  phenomena, in
as  much reality  though  less apparently indeed, than
adolescence, or manhood.
  In  the same way, the debility of any particular system
of the internal functions, may depend either on  original
constitution, or on  some  accidental vice  or  disease,  by

air in the other an accidental and purely  accessory circumstance ?  Do
we believe, that  if  by  any cause the  opening  of the  prepuce was
entirely obliterated,  the secretion of urine  would be prevented ?  Do
we not know that if instead of taking into  the mouth savoury food, it
is brought near to it, the saliva flows not  less, or in vulgar language
the  mouth waters ?  There is  however  no contact, there  is not any
mechanical or chemical  impression in the orifice of the salivary ducts.
            21 
162         PHYSIOLOGICAL RESEARCHES
which,  while  the  others  have remained  untouched, its
constitution may have been impaired.
  Such  then  is the great  difference of the two lives of
the animal, with respect to inequality of perfection in the
organs.   In the animal  life, the predominance or  inferi-
ority of one system, with relation to the others, depends
almost entirely-upon its activity or inertia, on  its habitude
of acting or not acting.   In the  organic life  on the  con-
trary, such states  are immediately connected  with the
texture of the organs, and never with their education.
  From  hence also we have the reason why physical
temperament,  and  moral character, are not susceptible of
change  from  education, which so prodigiously modifies
the actions of the  animal  life, for as we have seen, they
both of  them belong to  the organic life.
  The character is, if I may so express myself, the physi-
ognomy of passions ; temperament,  that  of  the internal
functions: now the one  and the other being at all  ages
the same, having a direction which habitude and exercise
can never alter, it is manifest that  they must ever be
withdrawn from the influence of education.  The  vio-
lence of the temperament may indeed  be moderated, for
the powers of the judgment, and  reflection may be  aug-
mented, and the  animal  life  strengthened in  such  way
as to give it a capacity of resisting  the impulses of the
organic  life;  but  to attempt  an  immediate  alteration of
the character, or of the passions, which are its habitual
expressions,  is an enterprise  analogous  to  that  of the
physician, who should attempt to elevate or depress, (and
that, for the entire life  of the patient,) the ordinary con-
tracting powers of the heart and  arteries.
   We should observe to such physician, that the circula-
tion and  respiration, are not  under  the dominion of the
will; and that they cannot be modified excepting in  pass- 
ON LIFE AND DEATH.
U3
ing into a state of disease.   The same observation might
be made  to those, who imagine that the character, and
consequently the passions may be modified.
                    CHAPTER X.

 OF  THE NATURAL TERMINATION OF THE TWO LIVES.

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

I.  In Natural Death the animal life is the first to cease.

  Natural  death is remarkable  for  the  following reason
chiefly:—it terminates the animal life, a long time before
it puts an end to the organic life.
  He who dies in  consequence of a very prolonged old
age,  dies in  detail; his exterior functions  are finished,
one after the other ;  the senses are shut up successively ;
the ordinary  causes of sensation pass over them,  and do
not affect them.
  The sight grows dull and confused;  it ceases at length
to transmit the images of objects: this is the blindness of 
164
PHYSIOLOGICAL RESEARCHES
old age ; sounds also, after a certain  time,  affect the ear
confusedly; the organ at last becomes entirely insensible.
The cutaneous covering of the body grows hard and dry;
it is the seat of an obscure and imperfect touch.  Besides
which, the habitude of  feeling has blunted the power of
feeling';  at the same time all  the other organs which are
dependent on the skin,  grow weak and perish ; the hair
falls, it is deprived of the juices by which it was nourish-
ed : to continue our description, odours make  but a feeble
impression upon the nostrils.
  The taste indeed  is a  little more kept up; but let it be
remarked that this sense is connected with  the organic as
much as  with the animal life, and is  therefore necessary
to the internal  functions:  In this way, when all agreea-
ble sensations  have  fled  the old man, when their absence
has already broken  in part the  connexions, which attach
him to the world, his taste remains with him still;  it is
the last thread to which  is suspended the pleasure of exis-
tence.
  In this way, isolated  in the midst of nature, already
deprived of the greater number of the functions  of the
sensitive organs, the old man is soon to suffer the  loss of
the  common action of the brain, for it is  manifest, that
there can scarcely be any farther  perception, for the very
reason that there is  nothing farther coming from the
senses.   Meanwhile, the imagination lessens and is soon
annihilated.
  The memory of present things is destroyed: the old
man  in an instant forgets what  is told him,  because his
external  senses enfeebled and already dead,  as  it were,
in no wise confirm  what is intimated to him by the mind
alone.  Ideas  escape  him  when  the images, which are
traced by the senses, do not keep  their hold.   On the
contrary, the remembrance of the past remains with him, 
ON LIFE AND DEATH.
165
fhat which  the  old man  has formerly known, has been
taught him or at least confirmed to him by his senses.*
   He  differs from the  child in  this  respect;  the child
judges  only  from  the sensations  which he  experiences,
the old man from  those, which he has experienced.
   The  result of the two states is  the same, for  the judg-
ment is equally uncertain, whether  founded exclusively
upon actual or past sensation.  Its accuracy depends upon
the due comparison  of the  two.   No one can  be igno-
rant, that in  the  judgment which we form from visible
objects, the actual impression would  frequently deceive
us, were  we  not to  rectify the  error by  what we  are
enabled to recollect,  and  may we not observe that past
sensations, in a  short time grow confused, if the features
of the  picture,  which they  have left with us,  be  not
retraced by new and  analogous impressions ?
   The present then, and the past with regard to  sensation,
are equally  necessary for  the perfection of the judgment.
If either  the one or the  other be wanting  there cannot
be any comparison made  between the two, and in conse-

  * If.the old  man preserves with difficulty  the memory  of the most
recent events, whilst he often retraces with the greatest ease the recol-
lection of the  most distant ones, it is not because the first have been
more faithfully transmitted to  him  by his senses,  but because  these
events had produced a greater impression  on  him.  This is so true, that
failure of the memory is sometimes remarked in old people who have
their senses in perfection.   On the other hand, very imperfect sensations
may produce  a  very lively impression.   A  connoisseur  in painting,
when his sight is very bad, experiences in seeing a beautiful picture, a
hundred times more pleasure, than one who  is indifferent to it, though
he examines it with good eyes, and the connoisseur preserves the image
of it long after the other has lost it. We do  not perceive the recollec-
tion of things, unless there is some circumstance connected with them
that makes a lively impression; but in  the  same  event,  this circum-
stance will not be the same in all individuals, and it is sometimes by
the most trifling of all that a man fixes the fact in his memory. 
166          PHYSIOLOGICAL RESEARCHES
 quence there must be a want of precision in  the judg-
 ment.
   For these reasons, the first and the latter ages of man,
 are equally remarkable for imbecility.  Old  age is second
 infancy.  The  two  periods of life resemble each other
 with regard to want of judgment;  they differ only as to
 the cause of such defect.
   The  interruption of the functions  of the brain of the
 old man, is a consequence of the almost entire annihila-
 tion of the sensitive  system with him ;  in the same  way
 does the  weakness  of  the  locomotive  power, succeed
 almost  inevitably  to  the  inactivity  of  the  brain.  This
 organ in fact re-acts upon the muscles, in proportion only
 as the  senses act upon it.
   The movements of the old man are few and tardy; he
 changes  with  difficulty the  attitude, into which he  has
thrown himself;  seated  near  the  fire, and  concentrated
within  himself, a  stranger to every thing without him,
he passes his days there, deprived of desire, of passion,
and sensation;  speaking little  because he  is determined
by nothing to break his  silence, yet happy in feeling that
he  still  exists, when almost  every  other  sentiment is
gone.
   The rigidity of the muscles however, and the diminu-
tion of their  contracting powers, is another cause  of
inactivity in the  old man,  and doubtless has its influ-
ence ;  but it is by no means the principal one,  since  the
heart and the muscular fibres of the  intestines, contract
the same  rigidity, arid  are  deprived of their powers of
moving, in a very different way from that, in which  the
voluntary muscles lose it.  With the voluntary muscles,
it  is not so much the power as  the excitant of the power
which  is lost.  If it  were possible  to  compose a man
 with the senses and brain of old age, and the muscles of 
ON  LIFE AND  DEATH.
167
youth, the voluntary motions of such man, would hardly
be more developed for the reasons which I have given.
  From the above it is easy to see that the external func-
tions  of the  old  man  are extinguished by degrees, and
that his animal life  has almost entirely ceased, while his
organic life is still in activity.   Under  this consideration,
the state  of the  animal about to suffer a natural  death, is
nearly similar to that of the  foetus  in utero,  or  of the
vegetable which lives within itself only,  and  for which
external nature is absolutely silent.
  If we now recollect that  sleep entrenches more  than
a third upon  the duration  of the animal life,  if we add
to this the total  absence of such life  for  the  first  nine
months of existence,  and  its almost  entire  inactivity
during the latter  period of existence,  it will be easy to
calculate  the  great  disproportion of its duration,  when
compared with that  of the organic life  which is exercised
uninterruptedly.
  But wherefore when we have ceased to exist without,
do  we continue to exist within, since our sensations and
above all, our powers of locomotion, are especially destin-
ed  to place us in  relation  with those substances, which are
to nourish us.   Wherefore are those  functions enfeebled
in  a  greater disproportion  than  the internal  functions,
and why  is there no exact relation in the times of  their
cessation.
  I cannot entirely resolve this question.  I shall  only
observe that society has an especial influence in creating
this difference;   for man  in  the  midst  of his fellow-
creatures  makes  a very great use of  his  animal life ; the
springs of it  are habitually more fatigued than those of
his organic  life,  and  worn  away under the influence of
society ;  the eye by artificial light, the ear by sounds too
frequently repeated, and  above all by those of speech, 
168
PHYSIOLOGICAL RESEARCHES
which are wanting to other animals ;* the  smell in like
manner  is debilitated  by factitious odours, the  taste by
savours, which  certainly are  not natural,  the touch and
the tact by  constant  attrition  of  dress,t and the  brain by
too incessant thinking.
  We live then externally with excess.   We abuse our
animal  life; it is circumscribed  by nature within  limits
which are too much  enlarged  by us for its duration; thus
it cannot be surprising that it should cease so soon.   In
fact we have seen  the  vital  powers  divided into two
orders, the one appertaining  to this life, the  other  to the
organic life.  These two orders  may be compared to two
lights which burn at the same time, and which have only
a determined quantity of materials for aliment.   In  which
case, if the one be agitated by a stronger wind  than the
other is, it  must necessarily be the sooner extinguished.
  Yet social influence notwithstanding is very advantage-
ous to  man.   It gradually disengages him  from  those
bonds which attach him to life, and renders the  instant of
death less terrible.
  The  idea of our  last hour, is  painful only because it
puts an end to our animal  life.   The borders of the tomb
are beset with terrors, which  will all be found to originate
in the thought of such privation.

  * This failure of the senses appears in animals as well as man, and
it may be observed in those whom  we  suffer to grow  old among us.
We often see dogs becoming blind and  deaf; and these infirmities are
perhaps  more common in them than in man. . But as these  animals
are  rarely permitted to arrive at extreme old age, we have not often an
opportunity of observing them.
  t By defending the skin  from the shock of external bodies,  and  by
preserving it  from the variation of temperature, dress very certainly
preserves its sensibility, and far from impairing the sense of touch, as
Bichat maintains, it acts as a circumstance favourable to its preserva-
tion. 
ON LIFE AND DEATH.
169
  It is not the pain of death, which we fear;  how many
dying men are there for whom the gift of existence would
be precious, though purchased at the expense of an unin-
terrupted series of suffering !   If we look at the animal
which  lives but little externally, he by no means trembles
at beholding the instant of his death.*
  Were it  possible  to  suppose  a  man,  who in dying
should  lose his internal functions only, such  man would
look upon his death with an indifferent eye, because he
would  feel that the blessings of existence,  are attach-
ed to the powers of feeling the  influence of nature and
society.
  If the animal life then be terminated gradually, if each
of the bonds  by which we are capable of the pleasures of
living, be  broken by little and  little, such pleasures will
escape us imperceptibly, and the old man will  have for-
gotten the value of life, when  it is about to be taken from
him ; such destruction will resemble  that of the vegetable
only.

II.  The Organic Life in natural death does not termi-
           nate as it does in accidental death.

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

  * The animal  no doubt does not tremble at the moment of death ;
 for he does not see it.  His present sensation i^ every thing to him.  If
he suffers at the approach of death, he shows it by the usual signs; but
it is only the present  pain that he expresses,  he sees nothing beyond.
 The child is in  this respect, in the same situation as the  animal.
               22 
170
PHYSIOLOGICAL RESEARCHES
by the slow and gradual extinction of the  other organic
functions.
   The parietes  of the stomach, for instance, continue to
act upon the aliment which may be found there, the juices
of the stomach continue to dissolve it.   The experiments
of the  English  and  Italian physicians upon absorption,
(experiments the whole of which I have repeated)  have
proved that this function not unfrequently remains in a
state of activity, after the general death of  the body, and
if not as  long as some have supposed, at least for a  very
considerable interval.   Discharges of  urine  and feces are
often  observed  to take place many  hours after sudden
death.
   The process of nutrition also continues to be  manifest
in the hair and in the nails; the same would doubtless be
the case in all the other parts, as well as in the secretions,
could we  observe the insensible movements of which  their
functions   are  the  result.   The heart  of the frog being
taken  away,  the  capillary circulation may still  be  seen
under the influence of the  tonic powers.   The  body is
very slow also in  losing its animal heat.*

  * In order to ascertain the cause of the  differences in the cooling
of the body after the various kinds of death, it is necessary to examine
what general conditions can have an influence in the cooling of a body
left to itself.  Of these there are three principal ones.
  Under the same external circumstances, a body will cool so much the
slower.  1st. As its temperature at  the beginning of the experiment,
shall be higher in relation to that of surrounding bodies ;  2d.  As its
surface shall be less in relation to its size ;  3d. And as its exterior parts
shall be less perfect conductors of heat.
  In order  to see how the first condition is modified  in different  cases,
it is  necessary to recollect what is the  source of animal heat.   The
blood is warmed in  passing through the lungs in consequence  of the
chemical phenomena of respiration;  and as from the lungs it is carried
to all parts of the body, it yields to the different organs a portion of
the heat which it has received.  Hence the general temperature  of the 
ON LIFE AND DEATH.
171
   I might augment the above observations with a number
of others, which would go to prove the same assertions; on

body will be  higher in proportion to  the temperature of the blood, to
the frequency with which this fluid is renewed  in the organs and to
the quantity of it that is brought to them, at each pulsation.
  Now in diseases of long duration, the volume of blood is considerably
diminished, the activity of the heart is lessened,  and  respiration is per-
formed in an  imperfect manner.  Thu3 the  body of the patient who
sinks  under these circumstances  has  less heat to lose than  that of the
man who dies suddenly, when all  these functions were performed in
perfection.
   Let us pass now to the second condition.   The cooling, as we have
said, takes place  so much the quicker as the  surface of the body is the
more extended in proportion to its size ; now, in the  emaciation which
accompanies  almost all diseases that are protracted,  the size decreases
much more rapidly than the surface.  Thus then, when  even at the
moment of death  the general temperature of the body may be as high as
in a state of health, the cooling would however take place more quickly.
   It remains for us now only to examine under what  circumstances the
third condition is fulfilled in the  most advantageous manner.  When
an individual  in  full  health dies,  the sub-cutaneous  cellular texture
usually contains a greater or less quantity of fat.  Now we know that
it is one  of the characters of all fat substances to be  very bad conduc-
tors of heat.   Hence   then a third reason which should render cooling
more slow after  sudden deaths.  Sometimes after a disease, this last
condition is fulfilled in another  manner.   In certain derangements of
the circulation, the cellular texture is filled with serum;  and as all
aqueous  fluids are bad conductors of caloric, though the  temperature
of the body may not be very high at the moment of death, the heat  is
yet preserved for a long time.
   To the different causes which we have just mentioned, there is some-
times added  another which is peculiar to  one kind  of sudden death.
It is observed  that in  the midst of the  same external circumstances,
the blood does not always cool with the  same  quickness,  and  that in
proportion as its coagulation is slower, its  heat is  longer preserved.
 Now, it is  a well known fact, that when death is the result of asphyxia,
the vessels are found  full of fluid  blood ;  this is also a  reason  which
 contributes to explain  the slowness of the  cooling.   And  it should be
 remarked, that asphyxia is one of the most frequent causes of sudden
 death either accidental or voluntary. 
172  PHYSIOLOGICAL RESEARCHES ON LIFE AND DEATH.

the contrary, in the death which is the effect of old age,
the whole of the functions cease, because they have each
of them been successively extinguished.  The vital pow-
ers abandon each organ by degrees, digestion languishes,
the secretions and  the absorptions are finished, the capil-
lary  secretions become embarrassed ; lastly,  the general
circulation is suppressed.   The heart is  the ultimum
moriens.
   Such, then, is the great difference which distinguishes
the death of the old man, from that  which is the effect of
a sudden blow.  In the one, the powers of life begin to
be extinguished in all the parts, and cease at the heart;
the body dies from the circumference towards the centre:
in the other, life becomes extinct at the heart, and after-
wards in  the parts.   The phenomena  of  death are seen
extending themselves from the centre  to  the  circumfer-
ence. 
BICHAT ON LIFE AND DEATH.
               PART THE SECONB.


                    CHAPTER I.


         GENERAL CONSIDERATIONS ON DEATH.

  In  the first  part of this  work, I have explained the
two great divisions of life, together with the remarkable
differences, which distinguish the animal existing without,
from  the animal  existing within.   I have  discussed the
characters which are exclusively proper to the two lives,
and the particular laws, according to which they  both of
them  commence, are developed and end in the  natural
order.
  In  this second part I  shall inquire  in what way they
accidentally finish, in what way their  course is  prema-
turely arrested.
  The influence of society  suffers us but rarely  to  live
out the period  which was intended us by nature ; while
almost every other animal attains  his  natural end, such
end in the human species is become a sort of phenomenon.
The different kinds then of accidental death, should engage
the particular attention of the physician and physiolgist.
Now  this sort of death may happen in  two ways :  some-
times it is ther esult of great disturbance excited  in the
economy ;  and  sometimes it is the effect of  disease.
  In  general it is easy enough  to discover,  according to
what  laws the functions are terminated  in consequence of 
174
PHYSIOLOGICAL RESEARCHES
any violent or sudden attack ;  of apoplexy, for instance,
great hemorrhagy, concussion of the brain, or  asphyxia ;
because in such cases the organs of the body, excepting
that which is immediately affected, are  not the seat of
any peculiar lesion, and cease to act from causes diametri-
cally the contrary of those, which  according to the com-
mon course of things maintain them in action.  Now as
these causes are partly  known,  their contraries may be
inferred; besides, we are capable of imitating these sorts
of death upon  animals, and consequently of  analyzing,
experimentally, their different phenomena.
  On the other hand it is seldom in our power to produce
artificially in the bodies of animals  the  diseases of the
human species.   Were we even possessed of such power,
we should gain but little knowledge from it: the laws of
life in fact are so changed, so modified, so altered in their
very nature,  by the  various morbid affections to which
the parts are subject, that but very seldom can we depart
from the known phenomena of the living animal, when
we undertake  to  inquire  into those which  it exhibits
in its dying  moments.  For such inquiries it would  be
necessary to know what is that intermediate state between
health  and death,  in which the functions experience so
remarkable a change; a change, which has such infinite
varieties, and produces such innumerable sorts  of disease.
But, where shall we find  the physician, who will assert
that from the actual data  of his art, he  understands in
such intermediate state, the profoundly hidden  operations
of nature ?
   In these researches  then, we shall occupy  ourselves
more especially on those  sorts of death which I first
enumerated.   Those, which have been mentioned in the
preceding paragraph will  engage us only now  and then :
besides, at my age I cannot be supposed to have acquired 
ON LIFE AND DEATH.
175
a sufficient degree of medical knowledge to treat of them
with advantage.
  The first remark, which the observation of the different
kinds of sudden death suggests, is, that in all of them the
organic life to a certain point may subsist, the animal life
being  extinct; but that the  latter is entirely dependent,
and lasts not for a moment after the  interruption  of the
former.  The individual,  who is struck with  apoplexy
may live internally for many  days after the stroke, exter-
nally he is dead . In this case death commences with the
animal life :  if on  the contrary it exerts its influence in
the first  place upon  any of the essential organic func-
tions—as on  the  circulation in wounds or on  respiration
in theasphyxise—the  animal  life is gone at once, together
with the sensible actions of the organic life.
  The red and warm-blooded  animal, loses his external
life at the moment when  he ceases  to exist internally,
the cessation of  the phenomena of his organic life is a
sure  index of his  general death;  indeed  the  reality  of
death  can  be pronounced only  from  such datum ; the
interruption of the external phenomena of life is in almost
every instance fallacious.
   On  what  depends  this difference  of the  manner  in
which the two lives accidentally end ?  It is owing to the
mode of that influence, which they exercise the one over
the  other, to the kind of bond,  by which they are con-
nected.
   This mode of influence,  this bond, appears to exist
between the  brain on the part of the  animal life and the
lungs, or heart on the  part of the organic life.  The action
 of one of these  three organs is  essentially necessary to
 that of the two  others ; and as they  constitute  the three
 centres, in which are  terminated  all  the secondary phe-
 nomena of the two lives, whenever they cease to  act, the 
176
PHYSIOLOGICAL RESEARCHES
 phenomena which depend upon them must cease also, and
 general death ensue.
   Physiologists have been at all times acquainted with the
 importance of this triple focus; and have given the name
 of vital to all those functions, which have their seat in it.
 Under the point of view which at present engages our
 attention their  ideas  on this head are  well  worthy of
 notice, for  every species of sudden death begins by the
 interruption of  the circulation, the respiration, or action
 of the brain.  In the first place, one of the three functions
 ceases, then the others successively; so that to expose
 with precision the phenomena of sudden death, we must
 consider them as they take place  in the three principal
 organs, which we have mentioned.
  We shall  first inquire  into those deaths,  which begin
at the heart, and afterwards  into  those, which begin in
the lungs and in the brain.  I shall explain in  what way,
when one of these organs is affected, the others die;  and
then demonstrate by what sort of  mechanism the death
of the various other parts of the body ensuses.  Lastly I
shall determine from the  principles, which I shall then
have laid down,  the  nature  of the different  species of
disease, which  are peculiar to the heart, the lungs,  and
the brain.
                   CHAPTER  II.

OP THE INFLUENCE OP THE DEATH OP THE HEART, OVER
                 THAT OP THE BRAIN.

  I shall evidently have determined what is the mode of
this influence, should I be enabled to establish in what 
ON LIFE AND DEATH.              177
way the action  of  the  heart  is necessary to that of the
brain ; for in this instance the cause of death will  be no
other than the  privation of the cause of life.   Now the
heart can only act  upon the brain  in two ways ; by the
nerves, or the vessels  which  serve as their connecting
medium.   In fact these two organs  have no  other means
of communication.
  It is evident  that the nerves cannot  be the  agents  of
such actions ;  it is  the  province of the  brain  to act by
means of the nerves.   The different  parts  of  the  body
never influence  the brain  by  such  means,  excepting  in
the sympathies.  If a bundle of nerves belonging  to the
voluntary muscles be tied, the muscles indeed will  cease
to act,  but  nothing will  be  changed in  the cerebral
mass.*
  I have ascertained by many experiments  that the phe-
nomena of galvanism, which  are  propagated so energeti-
cally from the brain towards the  organs, which descend,
if I  may so express myself, along the nerve, will hardly
ascend in a contrary  direction.  Apply the  apparatus  to
a nerve of the loins and the muscles of  the  upper limbs,
and  when the  communication is  made, there will  be
scarcely any contraction ;  but on the establishment of a
communication  betwreen the same  nerve and the  lower
limbs, a violent convulsive motion will instantly be occa-
sioned.  I have even observed, on placing two metallic
plates, the one  under the  lumbar nerves, and  the  other
under the upper limbs, that  the communication of the
two  plates  by means of a third metal, will cause a con-

  * It is not true that a ligature on a nerve produces its effects only on
the part to which this nerve is distributed;  the brain is also affected;
for, without this, how can be explained  the pain that is felt, and the
excitement, which is often sufficiently powerful to produce  convulsions,
and sometimes even death.
              23 
178          PHYSIOLOGICAL RESEARCHES
traction of the lower limbs, while the upper limbs remain
inactive, or move but feeble.*
  These experiments are particularly applicable to the
relation of the heart with the brain; for not only is it true
that the section, ligature or compression of the cardiac
nerves  are of little effect with regard to the functions of
the latter, but it is true also, as  we  shall  presently see,
that they do not directly modify the movements of the
former.  We may conclude that  the vessels are the exclu-
sive agents of the influence of the heart upon the brain.
  The vessels, as every one  knows, are of two sorts—
venous  or arterial—they carry black or  red blood, the
latter answer to the left side, the former to the right side
of the heart.   Now their functions  being very different,
the action of one of the portions of this  organ  on the
brain, can never be the same as that of the other portion.
We shall inquire  in  what way  they both  of them act
upon it.
  In  naming these two portions, I shall  not make use of
the expressions of right and left to distinguish them, but
of those of the  red-blooded and  the black-blooded  heart,
for each of these portions of itself is an  isolated organ,
distinct from that to which it is applied, and in the adult
especially so.   In fact there are two hearts, the one arte-
rial,  the  other venous, notwithstanding  which, we can
hardly  employ these  adjectives  for the purpose of desig-
nating them, since they both alike possess their arterial and
venous appendages.  On the other hand, they are neither
of  them situated exactly to the right or to the left, are

  *The  facts related here  by Bichat are not conformable to those,
which, the philosophers and physiologists have observed who have been
more particularly engaged with this kind of experiments.  Besides the
consequences which he has  drawn from them are not accurate, and
he seems to be ignorant what course the galvanic fluid in this case takes. 
ON LIFE AND DEATH.
179
neither of them exactly forwards or backwards.  Besides
which these latter  denominations  would  not apply  to
animals.

I. In what way does  the cessation of the functions of
   the red-blooded heart interrupt the functions of the
   brain ?

   The red-blooded ventricle and auricle, exert their influ-
ence  upon the brain by  means of the fluid  which  they
send  thither through the carotid and vertebral arteries.
This fluid may excite the cerebral organ  in two  ways.
1st.  By the  movement, with  which it is directed.   2nd.
By the nature of  its colouring principle.
   It is easy to prove that the movement of  the blood is
necessary  to the life  of the  brain.   Expose the brain of
an animal in part, and tie the carotids.   In such case the
cerebral movement will be sometimes weakened, and then
the animal will be  stupified,  at other times the vertebral
arteries will  exactly  supply the place of the carotids, and
then  there will be  nothing  deranged  in  the  principal
functions  of the  brain ;  for  there  is always  a relation
existing between the alternate rise and fall of the cerebral
mass, and the energy of life which it displays.*
   In  general,  the obliteration  of the  carotids is  never
suddenly  mortal.   Animals  will live without  them, at
least  for a certain time.  I have kept dogs  in this state

  * If there is always a relation between the vital energy of the brain
and its alternate  motions, it is because there is  a  constant relation
between these motions and the entrance of the blood into the organ.
Thus then, instead of considering this shock as the  exciting  cause of
the brain is it not  more natural to see in it only an effect purely acci-
dental of the arrival of the arterial blood, which every thing proves tr
be thf real excitant? 
ISO          PHYSIOLOGICAL RESEARCHES
 for several days and have  afterwards  made use of them
 for other experiments:  two  however  died  in the course
 of six hours, after the application of the ligatures.
   After having  made the  above experiments  which  go
 very far to the establishment of the principle which I am
 labouring to prove, let a piece of the  cranium  be  taken
 from another animal and tie the vertebral and carotid arte-
 ries.   The movement of the brain  will  then be entirely
 interrupted and the animal immediately die.
   The impulse, which proceeds then from  the influx of
 the blood  into  the  brain, is  a condition  essential to the
 functions of this  organ, but other proofs may be adduced,
 for the establishment of  the truth of this assertion.
   1st. There are a number of compressions, which  can
 only act by preventing the brain from being duly affected
by such impulse.  A collection  of pus, or blood, will
often put a stop to all the functions, which relate to the
perception, memory, and voluntary motions  of  the indi-
vidual.   Let such compression be removed and his sensi-
bility will  immediately re-appear.   In  such case,  it is
manifest that the brain  was  not disorganized,  but only
compressed, and  in a state incapable of being excited  bv
the heart.*
  I do not think it necessary on this subject to  cite cases.
All authors, who have treated of wounds of the head, are
full of them.  I  shall  content myself with remarking,
that the  same effect  may be  artificially produced  in  our
experiments upon animals,  and that accordingly as  the
brain is compressed or free, the creature will  be insensi-

  * As we know absolutely nothing of the manner in which the intel-
lectual phenomena are produced in the brain, we cannot  say whether
compression prevents their development by stopping the motions with
which  the brain is habitually agitated, or by preventing the entrance
of the arterial blood, or finally in some other way that we do not suspecf 
ON LIFE AND DEATH.
181
 ble, or  the  contrary.   According to the degree of the
 compression, will be the degree of the stupor.
   2dly.  There are reptiles, in the  brain  of which  no
 motion whatever is  occasioned by the heart.   The frog'
 is of this species.  On  raising the upper portion of the
 cranium, and exposing  the brain, there  cannot be per-
 ceived the slightest  motion.  Now in this species, and
 that of the salamander,  the influx  of blood may be cut off
 from the cerebral organ without  occasioning the imme-
 diate death  of the animal.   The voluntary  muscles  for
 instance continue to act;  the  eyes to exhibit a lively  ap-
 pearance, the tact also of the creature is manifest for some
 time after the heart  has been  taken away,  or  the double
 branch which proceeds from the single ventricle of  these
 animals  has been tied.*   I have frequently repeated  these
 experiments, and  have  constantly found the  effect the
 same.
   3rd.  It is  a general  observation, that those animals
 which have a long neck, and in which the  heart for that
 very reason  is not so capable of exerting a lively influ-
 ence over the brain, have a more limited  intellect, and
 the  cerebral functions less  marked.   On the  contrary a
 very short neck, and the approximation  of the heart to
 the  brain very generally are found to coincide with the
 latter.   Similar  phenomena are sometimes observed in
 men.   They who have the neck particularly long are
 dull, they who have it short, for the most part intelligent
 and  lively.

  *The organization of these animals differs too much  from that of man
to enable us to draw conclusions from one to the  other, especially in
what concerns the functions of the nervous system.  There is an expe-
riment of M Dumeril in which a salamander lived a long time after the
amputation of the head, till the formation of a perfect cicatrix  in the
n^ck, which intercepted the passage of air to the lungs. 
182
PHYSIOLOGICAL RESEARCHES
  From these many facts we may confidently assert, that
one of the means, by which the heart maintains the brain
in action, consists in the  habitual  movement, which it
impresses on it.
  But this movement is  essentially  different from that
which in  the  other viscera, such as the liver, or spleen,
is derived from the  same  cause.  In  these  it is little
manifest, in the brain it is very apparent;  the reason is
evident;  the large arterial trunks of the  brain, are situated
at its  base, between the  brain and  its bony  parietes ;
in consequence  of which, at each diastole, the vessels
experience a resistance from the bone,  which is commu-
nicated immediately to the cerebral mass.  At such time
the brain is really lifted, just in the same way as we see a
tumour lifted by the arteries which creep along the  bones
beneath it; and  instances of this are frequent.   So appa-
rent indeed  is  the motion of  tumours when  they are
situated over  the  carotid, as it lies  upon  the vertebral
column, or over the femoral artery, immediately after its
passage under the crural arch, as often to occasion doubts
with respect to their nature.
  But no other organ is  enclosed within a bony cavity;
the motion  of the  arteries every where else, is  lost in
the surrounding cellular  substance, or  soft parts.   Such
motion, then, is unessential to the functions of the liver.,
the kidney, and  other analogous viscera.
  The integrity of the functions of the  brain, is not only
dependent on the mere motion, but on the sum also of
the motion communicated.  It is equal1.}' impaired by too
much, or by too  little  motion.  Of this  assertion the
following experiments are  proofs.
  1st. Inject water by the carotid of a dog; the presence
of this fluid in the brain is not pernicious, and the animal
will live very well, when the injection  has been skilfully 
ON LIFE AND DEATH.
18-3
 made.   But  if it be  pushed with violence, the  cerebral
 action will immediately be troubled, and often cannot be
 restored.*   In every  experiment, there will be found  to
 exist a relation between the force of the impulse and the
 state of the brain;  if the pressure be but a little augment-
 ed, its effects will be instantly seen  in the  agitation of the
 countenance of the creature;  if relaxed, a corresponding
 calm will succeed  ; if increased  to the highest pitch,  it
 will immediately occasion death.
   2dly. If the brain be exposed, and an artery afterwards
 opened, so as to  produce a considerable  hemorrhage, the
 motion of the brain will  be diminished in proportion  as
 the  afflux of  the blood to it  is diminished, and finally
 will  cease entirely.   Now, according to all  these various
 degrees of diminution,  which may be  observed in the
 movements of the brain, will  be the corresponding weak-
 ness  of  the cerebral influence as it is discoverable in the
 state of the eyes, the touch, and the  voluntary motion  of
 the animal.t
   Hence it  is easy  to see, why a state of  prostration and
 languor is always the consequence of great hemorrhage—

  * Why are not the cerebral functions disturbed, when water is pushed
 slowly into the carotids? because there is then mixed with  the blood
 of the artery too small a quantity of water at a time to enable this fluid
 to have a very evident  action on the brain.  But  if this  introduction
of water into the mass of  blood continues, whatever precaution may
be taken, its effects soon  show themselves.  Wre  have  often, in our
experiments, introduced a great quantity of water into the veins of  an
 animal, and though much  of it passed off by pulmonary transpiration,
the arterial blood soon became very  aqueous.  Now, we have always
observed, that in this  case, the  animals were struck with  a  kind of
stupidity, which evidently indicated a want  of action of the brain.

  f It is not uncommon to see patients, who retain their intellectual
faculties perfectly, when the motions of the heart are so feeble, that
they certainly cannot produce, in the  mass of brain,  any sensible jar. 
184          PHYSIOLOGICAL RESEARCHES
and from what has been said above we may conceive the
reason, why the arterial system of the brain has been at
first concentrated at its  base, while the  larger venous
trunks are almost all of them  situated on  the  convexity
of its surface.  The base of the brain is small  and easily
moved, the convexity  large and  little capable of trans-
mitting motion, such as could be made upon it by vessels.
Besides, it is at the lower part  of the brain that exist its
particular and essential  forms.  The lesions of these are
mortal, and consequently their  functions must  be impor-
tant.   On the contrary, experiment and observation alike
have proved, that  very  little derangement  follows, from
cutting or rending the substance of the upper part of this
organ.  Hence also we may  see  the  reason, why  its
natural defences towards its base, are constituted in  such
way as to be  almost  impenetrable, and why at its upper
surface, it is less protected.  Now, where its life is indis-
pensable,  and its  action absolutely necessary, it should
naturally receive  the first and undiminished  impulse of
its  excitant.   We may conclude,  that the  interruption
of the action of the  red-blooded heart is the occasion of
interruption in the action  of the brain by annihilating its
movement.
  But this movement  is not the only means  by which
the influence of the heart is exerted on  the brain ; for if
it were so, we might easily reanimate the enfeebled func-
tions of the latter, by injecting it with water at the same
time through both the carotids. If pushed with an equal
force, the black blood and the  red blood alike would be
capable of keeping up  its action ;  but  this, as we  shall
presently see, is not the fact.
  The heart,  then, acts upon  the brain by the nature of
the fluid which it  sends thither ;  but as the lungs are the
focus, where the  blood undergoes an alteration, we  shall 
ON LIFE AND DEATH.
185
refer the examination of its influence upon the cephalic
system, to the chapter in which we shall treat of the
relation of this system, with that of the lungs.


II.  In what way does the cessation of the functions of
  the  black-blooded heart interrupt the functions of
  the brain?

  It very rarely happens that  general death  commences
by  that of the venous  auricle and  ventricle.  On the
contrary,  they  are almost always the last in action, and
when they cease to act, the brain, the lungs, and the red-
blooded heart have already ceased to exhibit their respec-
tive phenomena.  Nevertheless the contraction of these
cavities may be annihilated, or rendered at least ineffica-
cious with regard to the circulation, from the rupture of
an  aneurism or similar causes ;  in which case  the  brain
becomes inactive and dies, as  we have shewn it to do in
the preceding  section,  from want of movement.
  There is another kind of death of the brain depending
on  the interruption of  the transmission of blood from the
head to the heart,  as when the jugulars are tied.  The
venous system, in  consequence, is glutted and the brain
compressed, from the  continued afflux of the red  blood
into its arteries; but the phenomena of  this sort of death
are already sufficiently known.
  In the present chapter it is my intention to examine a
species of death, the principle of which by many physi-
ologists has been placed in the heart, but which  appears
to me to affect the head only ;  I mean that death which
may  be  occasioned  by  the  injection   of air into the
veins.
              24 
186           PHYSIOLOGICAL  RESEARCHES
   It is generally known, that as soon  as any quantity of
 this fluid is introduced into the vascular system, the move-
 ments  of the heart  are accelerated, that the creature is
 much agitated, cries with pain,  is convulsed, and soon
 after deprived of its animal life, but lives organically for
 a  certain time,  and  then  invariably dies.*  Now, what
 is the organ so readily affected by the contact of air?   I
 affirm it to be the brain,  and not the heart; and main-
 tain that  the  circulation is annihilated,  only because  the
 cerebral actions have previously been so.
   For, in  the first  place,  in this kind  of death, the heart
 continues to beat for some time after the cessation of  the
 animal life, and consequently for some  time after that of
 the action of  the brain.t
   Secondly,  By injecting  air into the brain through  one
 of the carotids, I have caused the death of  the  creature
just in the same way as when air is introduced  into  the

  * A very considerable quantity of  air can be forced into the veins of
 an animal, without  causing its death, provided  it be not  pushed in
 suddenly.  In all these cases, it is understood, that  the quantity  that
 can be thus introduced is in proportion to the size of the animal.  I
 have before me at this moment the details of an experiment that I made
 on a horse at Alfort with M. Dupui,  and in which, before the  animal
 died, I was able, in thirty seven minutes, to  inject  quickly into the
 veins forty syringes full of air, and three  syringes full into the carotid
 artery.  (The capacity of the syringe was seventeen centilitres.)  The
 animal died three minutes after the last injection.   At the examination
 of the body, we  found air in the  azygos vein and  in the thoracic duct,
 which contained much lymph, as well as the  lymphatic vessels of the
 interna]  surface  of the lungs.  The heart was enormously distended
 with air mixed with a small quantity of blood.

  | This is not correct, and death takes place, on the contrary, by the
 cessation of the  motions of the heart.  The right  ventricle is filled  with
 air; and this air, dilated by heat, so distends it,  that it can no longer
 contract. 
ON LIFE  AND DEATH.               187
veins ;  excepting only with a previous palpitation of the
heart.*
   Thirdly, Morgagni  has cited a number of cases of sud-
den death, the cause  of  which  should appear,  from his
remarks, to be  the repletion of the blood vessels of the
brain by air, which had  been developed there  spontane-
ously, and which  he  says, by its rarefaction,  compressed
the origin of  the  nerves.  I  cannot  suppose  that  such
compression can  be  effected  by the very small quantity
of  air,  which,  when injected into the carotid, is sufficient
to  occasion death; accordingly, I should  doubt whether
this compression were real  in the cases adduced, but  for
this, they are  not the less important.  Whatever be the
manner  in which  it   kills,  air  is   fatal whenever intro-
duced  into the brain, and this is the essential  point.   It
is with the fact that we have  to do and not the  manner.t

   * The disorders which are produced in this case do not  at all resem-
ble those which follow the entrance  of air  into the veins.   If we push
towarJs  the brain,  by the carotid artery,  a small  quantity of air, we
see almost immediately signs of a strong cerebral congestion, spasmodic
stiffness  of the muscles,  loss  of sensibility, and of the action  of the
senses, and all the phenomena of a real  apoplexy.  Respiration  and
the circulation go on  some time without  any apparent  alteration, but
finally these two functions become embarrassed  and the animal sinks.
Ev< ry thing leads to the belief, that  the alteration in the circulation of
the brain depends here on the presence of rarefied air  in  the ultimate
arttrial ramifications.
   When apoplexy is thus produced  by the injection of air, if it be still
forced into the artery, it  breaks open violently a passage for itself, it
tears the small vessels, and spreads in the parenchyma of the brain,
which it  makes  emphysematous and  crepitating  under the  finger.
There finally returns a portion of it by the  veins, which goes to the right
cavities of the heart and  which contributes to arrest the circulation.

   f In the two examinations related by Morgagni, it appears that after
a sudden death, there was found in the vessels of the brain an aeriform
fluid, to the presence of which, for the want of another material cause, 
 188            PHYSIOLOGICAL RESEARCHES

   Fourthly, As often as an animal is killed by the insuf-
 flation of air into one of its veins, I have ascertained that

 was attributed the  death of the  individual; but there is no proof that
 this fluid  might  not  be developed there after  death.  We shall  now
 relate a more decided case of death occasioned by the presence of air
 in the blood vessels; but here there is no ground for doubt, because
 we know the circumstances of the introduction.
   A locksmith, twenty three years of age, had  had for five years a
 large tumour on the right shoulder and clavicle.   His acute sufferings
 induced him to enter  the hospital to have it removed.
   It was necessary  in the operation to remove the middle portion of the
 clavicle.  Thus far the success was complete ; but little blood was lost,
 the pulse was good and the breathing easy, when  the patient suddenly
 cried out,  My blood is leaving my body ! I am dead.'   And at the same
 moment he became stiff, lost his consciousness, and was covered with a
 cold sweat.  A singular and rather loud noise was heard in the interor of
 his chest.  The surgeon thought that he had opened the pleura by remov-
 ing a portion of the clavicle, and thus given access to the air and to the
 blood to the right side of the thorax.   The fingers of an assistant were
immediately thrust into the  bottom of the wound, with  the view of
stopping the supposed opening in the pleura, and  the surgeon endeav-
oured to introduce into the thorax the extremity of a sound of gum
 elastic.  When he thought that  he  had  succeeded, he drew with his
mouth the  air which he supposed  to be effused in the pleura.  He wished
 then to proceed to the dressing ;  and, in order to do this, he substituted,
for the fingers of the  pupil which were at the  bottom of the wound, a
sponge covered with  wax; but the moment the sponge took the  place
 of the  fingers, the  same noise that was  at first heard and which had
ceased in an instant,  was renewed with more force than before.
   The syncope and cold sweat still continued.  Water thrown into his
face, made him give  some signs of life ; but he  died a quarter  of an
hour after  the  appearance of the accident I have just described, and
forty five minutes after the commencement of the operation.
   The body was examined the  next morning.  They expected to find
the right pleura open, much blood  and air effused into  its cavity and
the lungs on that side collapsed.   Nothing of the kind was found.   The
pleura was whole and  there was no effusion in  it.  The lungs were
as usual ;  but an opening of half an inch in  extent was discovered in
the external jugular vein, at the  place where this vein opens into the
 subclavian.  The cavities of the  heart were large but contained no 
ON LIFE AND DEATH.
189
 the whole of the red-blooded, as well as the black-blooded
 heart, is  full of a frothy blood, mixed with air  bubbles;

 blood.  Bubbles of air were observed in the  vessels of the  brain; the
 other vessels were not examined
   This fact was related to me  the  same day, by a student who was
 present.  It was impossible for me not to refer the death in this instance
 to the entrance of air into the vessels.  The opening in the  vein, the
 noise that  was heard, the suddenness of the death, the absence of blood
 in the cavities of  the heart, the presence of air in the vessels  of the
 brain, all  sufficiently indicated it.  I suspected that the  entrance  of
 air had been favoured  by the state of tension of the  parietes  of the
 vein, or by their morbid alteration, which did not allow them  to flatten
 by atmospheric pressure.   1  thought that this  phenomenon  might be
 produced  at will  on animals by placing them  in the same  physical
 circumstances.   I  introduced then  into the  jugular vein  of a  dog,  a
 sound of gum  elastic,  and I directed it  towards the heart.  It was
 hardly there before I heard the air enter the vein, and  the  animal fell
 down in syncope, with the peculiar noise which manifests the  presence
 of air in the heart.   I immediately  closed the sound  to prevent the
 entrance of more air, and the animal gradually recovered,  because the
 quantity of air introduced  had not  been in  sufficient quantity to pro-
 duce its death.    I then opened  the sound,  and immediately the air
 rushed in towards  the heart, and its  entrance  was followed  by the same
 consequences;  but, whether from not closing the sound soon enough,
 or from the entrance of a greater quantity  of air, the animal died unex-
 pectedly to me.   In opening it, I found all the signs of death  from the
 sudden entrance of air  The right ventricle was distended  with  air
 mixed with a little blood.
   Sometimes, without any  apparent alteration  in the texture  of the
 veins, its parietes do not flatten  under atmospheric  pressure; a simple
 puncture then is sufficient, as in bleeding, to  admit the air into the
 vessels.  Lieutaud relates two cases in which it appears that  this took
 place, and  several  veterinary surgeons have assured me that they have
 heard, after bleeding in the jugular vein,  a noise which indicates the
 entrance of air.   Usually  the quantity introduced is too inconsiderable
 to produce any evident  effects.  There has been communicated  to me,
however, a case observed by Mr. Bouley, the  younger a  veterinary
 surgeon in  Paris, in which the entrance of air was  followed by  effects
 similar to those which we have related.
  Mery had long since observed, that, in opening the abdomen  of a dog. 
190
PHYSIOLOGICAL RESEARCHES
and that  the carotids, and vessels of the  head, contain a
similar blood; such blood must act upon the brain, in  the
same  manner as it does  in the  two sorts  of apoplexy, of
which we have just been making mention.
   Fifthly,  If air be pushed into one of the  divisions of
the vena  portae from the  side of the liver, it oscillates in
the greater trunks of that organ for a considerable  length
of  time,  and arrives but slowly  at  the  heart.—In   ihis
instance  I  have  observed,  that the  animal experiences,
only after a  certain  interval,  those affections which  are
sudden when the  fluid is  injected into the veins  of  the
principal  system.*

and puncturing the vena cava above the origin of the emulgents, as the
vein become emptied  of blood, it filled with air, which went to the
right ventricle.  Haller also observed that air  entered into the  veins of
frogs and other cold-blooded  animals in  consequence of a wound of
some large  vessel.   He has shown that it was from this source that was
derived  that which  Redi, Caldesi, and Morgagni saw circulating in the
vessels of these  animals, since  it is not observed, when the  necessary
precautions  are taken to prevent its introduction.
  Nysten has made a great number of experiments upon the injection
of elastic fluids into the veins, and the results which  he has obtained
accord perfectly with those which we have observed.   He is not satis-
fied with injecting atmospheric  air, he  has introduced in the  same  way
a great number of other gases.   He has remarked, that among the gases
not  deleterious he can introduce, without causing death, a much greater
quantity if these gases are easily dissolved  in the blood.
  We cannot follow him in the detail of these experiments; we shall
only relate  a result relative to the colouring of the blood in the lungs.
He  has observed, that by injecting air into the vein, so slow  as not to
produce the death of the animal, the colouring of the arterial blood is
rendered imperfect.   He is satisfied, he says, that it  is not owing to the
embarrassment of the lungs.  The injection of oxygen does not alter
this colouring.  The injection of azote completely prevents  it; that of
the  oxide of carbon does not produce any change in it.  I give these
results from his work; I have not had occasion  to verify them myself.

  * When air is introduced into the vena portae, there is not  only no
ill effect at the moment of injection, but there usually follows no 
ON LIFE AND DEATH.
191
   Sixthly, The  rapidity with which,  in  certain experi-
ments, the annihilation of the cerebral action succeeds to
the  insufflation of air  into the veins,  might almost per-
suade  us that such phenomenon is occasioned, as it is in
wounds of the heart  and syncope;—but  1st. The most
simple inspection  is sufficient  to shew us that the heart
continues to act after the apparent death of  the animal—
2dly.  As the motions of the heart are prodigiously accele-
rated  by  the contact of the  foreign fluid, they push  on
the frothy  blood with an extreme velocity, and hence we
have the reason, why the brain in such case  is so rapidly
affected.
   Seventhly, Were the  cerebral action  in  this sort of
death  interrupted for want of movement from the heart,
it would happen  as it does in  great hemorrhages of the
aorta ; that is  to say,  without  violent convulsion.  But
here, on the  contrary,  the  convulsion  is  extremely vio-
lent, immediately  after  the injection,  and consequently,

apparent effect on the  animal.  It is not  the same when air is injected
into the veins of the general system, with so much  care as not  to pro-
duce instantaneous death by the dilatation of the heart.   The effects do
not then appear till a long time after the injection ; but  they are wholly
different from the  primary effects which we have described.
  These consecutive symptoms from the entrance of air into the veins
are, as  Nysten has remarked, the result of an obstruction of the lungs
produced by the accumulation of air in the last divisions of the pulmo-
nary artery.  The embarrassment in respiration often appears at the end
of half a day, it becomes greater and  greater, the bronchia; are filled
with a viscid fluid; and the animal usually dies on  the third or fourth
day.  On examination of the body, no air is found in the heart or the
vessels; but the  lungs, instead  of being  pink-coloured, are greyish,
tinged with brown, and loaded with  frothy blood and mucus.
  Boerhaave thought, that death which follows the injection of air into
the vein? was always owing, as it is in this case, to the  presence of the
air, which offers, in the small vessels,  a mechanical  obstacle  to the
passage of the venous blood. 
192          PHYSIOLOGICAL RESEARCHES
announces the presence of an irritating substance  on the
brain.
  We  shall  conclude, that in the accidental mixture of
air with the  blood of the venous system, it is the brain
which dies the first, and that the defth of the heart is the
consequence of the death of the brain.   I shall explain
in another place, in what way this phenomenon is occa-
sioned.
                   CHAPTER III.

OP THE INFLUENCE OF THE DEATH OF THE HEART OVER
                THAT OF THE LUNGS.

  The lungs are the seat of two very different sorts of
phenomena.  The  first, which are  entirely mechanical,
are relative to the rise and fall of the ribs and diaphragm,
to the dilatation and contraction of the air vessels, and to
the entry and exit of the air, which is the effect of these
movements.  The second, which  are  purely chemical,
may  be referred to the different alterations, which  the
air and blood experience.
  These two sorts of phenomena have a mutual depend-
ence on each other.   Without  the mechanical, the chemi-
cal changes could  not be made; without  the  chemical
changes, the blood would cease to become an excitant to
the brain, in consequence of which that organ would  no
longer operate upon the diaphragm or intercostal muscles;
the muscle* themselves would  then become inactive, and
the motions of  the  thorax be  annihilated.   These phe-
nomena, however, are put an end to in a different manner 
                 ON  LIFE AND DEATH.             193

by the death of the heart, accordingly as it happens on
one or the other side.

I.  In what manner are  the actions of the lungs inter-
  rupted when the black-blooded heart ceases to act?

  The heart has certainly no influence over the mechani-
cal  functions of the lungs, but it contributes essentially
to produce the chemical  changes which are  made there,
by sending thither the fluid which  is destined to undergo
a change.  When its functions then  are interrupted as
may happen from  wounds or  be occasioned by ligature,
the chemical changes which should  be rrade in the blood,
are  suddenly  suppressed ; though  the  air  continue to
enter into the lungs,  from the  dilatation and contraction
of the chest.
   Meanwhile  there  arrives nothing at the red-blooded
heart, or* so little as to be insufficient for the production
of the cerebral movements.   The  functions of the  brain
are  consequently  suspended,  and  of course the move-
ments of the diaphragm  and ribs.

II. In what manner are the  actions of the lungs inter-
   rupted,  when  those  of the red-blooded  heart are
   suspended.

   Whenever  from  wound,  ligature,  or  aneurism, the
functions of the red-blooded heart or aorta cease, the func-
tions of the lungs are terminated in  the following order:

   * After the obliteration of the ductus arteriosus, the left ventricle
receives no blood but what comes from the lungs; now, if the motions
of the thorax continue, it is  red blood ; at least so long as the air is
freely admitted into the bronchial tubes, and so long as the composition
of this fluid is not changed by the mixture of foreign gases.
               25 
194
PHYSIOLOGICAL RESEARCHES
  1st.   There is no further impulse made upon the brain,
2dly, No further  movement of that  organ*   3dly, No
further action exercised upon the muscles.  4thly, No fur-
ther contraction of the intercostals or  diaphragm.  5thly,
The mechanical  functions  of  the lungs cease.  6thly,
Their chemical functions cease.
  In the former case, the chemical changes could not  be
made for want of  blood.  Here they  cannot be made  for
want of air.   Such is the difference  in the death of the
lungs,  in  consequence  of that of the heart,  according
as the  latter is affected.  But  as  the  circulation  is very
rapid, there cannot be but a very  short, interval between
the interruption of the chemical and the mechanical func-
tions ef the lungs.
                   CHAPTER  IV.

OF THE INFLUENCE OF THE DEATH OF THE HEART OVER
             THAT OF ALL  THE ORGANS.

  I shall divide this chapter, as the preceding one, into
two sections.   In the first I shall examine, how the death
of the red-blooded heart, in the second how the death of
the black-blooded  heart, is the  cause of the death of all
the parts of the body.

I. On the death of the red-blooded heart, and how that
           of the organs is occasioned by it.

  All the functions belong either to the animal, or to the
organic life.  Hence the difference of their classes.  Now

  •These two modifications should, after what we have said, be reduced
to a single one, viz. want of excitement of the brain by the arterial blood. 
ON  LIFE AND DEATH.              195
the death of those of the  first  class, in consequence  of
lesions of the red-blooded auricle and ventricle, is caused
in two ways, and  first, because the brain in  such case is
rendered  inert from  want of impulse, and  can  neither
have sensations, nor exercise an influence over the loco-
motive and vocal organs.
   Accordingly, all this order of functions is stopped, as
when the encephalic  mass  has experienced a violent con-
cussion.   It is  in  this way that a wound of the heart, or
the bursting of an aneurism, annihilate  all our relations
with external  objects.
   So strict a  connexion between the movement of the
heart, and the  functions of the animal life, is not observa-
ble in those animals  in which the brain, in order to act,
does not require the habitual stroke of the  blood.   Tear
away the heart of a  reptile, or  tie its  large vessels, and
it will continue for a long time to move and have sensa-
tions.
   Besides, supposing even that the action  of the brain
were not to be suspended from lesions of the red-blooded
heart, the animal  life would not, on that account, be the
less put  an end to ; because  to  the  exercise of the  func-
tions of -this  life,  is  attached as a  necessary  cause, the
excitement of its organs by theafflux of blood into them :
now this excitement, both here  and every where else,
depends upon two causes.—1st, On the movement  impress-
ed,  and  2i\\y, On the  nature of the blood.   At present
I shall only examine  the first  mode  of influence  ; the
latter will come under our consideration, when we speak
of the lungs.
   Habitual  motion is  necessary to all  the  parts of  the
body alike, is a condition essential to the functions of the
muscles, the glands, the vessels, and the membranes, &c.
 But this movement,  which  is partly derived from  the 
196          PHYSIOLOGICAL RESEARCHES
heart, is very different from that which is communicated
by the blood to the brain.
   The  latter  organ  receives an  impulse by  which  the
whole of its mass is visibly raised, an  impulse,  in  the
intermission  of which  the whole of  its mass  subsides.
On the contrary,  the  interior  movement, by~ which its
practicles are affected, is scarcely marked at all : and this
depends upon the smallness and the delicacy of the  vessels
by which its substance is penetrated.
   The  contrary of  this appearance is observed  in  the
movement occasioned in the other organs by the influx
of the blood into  them :  we see them neither rise  nor
subside; there is nothing  like a general impulse made
upon  them, because, as  I  have  said,  such impulse is lost
from  the  little resistance  of the surrounding  parts.   On
the contrary, they are penetrated by vessels of considera-
ble magnitude, which create an intestine motion,  oscilla-
tions, and impulses  adapted to the actions of the tubes,
lamellae, or  fibres, of which they are composed.  This
difference of movement  may be easily conceived, by com-
paring the manner in which the brain  on the one hand,
and on the other the liver, the  spleen, the  muscles, or
the kidneys  receive their blood ; indeed it  is  requisite
that the brain  should  be  distinguished from the other
organs, in the manner of receiving its impulses, because
it is enclosed in a case of bone, and consequently abstract-
ed from the thousand other causes of agitation,  to which
the other parts of the body are exposed.
   For we may remark, that all  the  other organs have
about them a number of agents, which are  destined to
supply the place of that general impulse, which is want-
ing to them on the part of  the heart.  In the breast, the
intercostals  and diaphragm are  continually  rising  and
falling ; the lungs and the heart are successively the seat 
ON LIFE AND DEATH.
197
 of a  dilatation and  contraction.  In  the abdomen, there
 is an uninterrupted  agitation produced, by the influence
 of respiration upon its muscular parietes ; an incessantly-
 variable  state  of the  stomach,  intestines and  bladder.
 Lastly, from the various  contractions of the muscles, the
 limbs have a still more evident cause of movement.
   Nevertheless,  it  is  probable that every one of  the
 organs, as well as the  brain, has a'general though obscure
 movement  impressed  upon it, from  the pulsation of the
 arteries;  and  hence, perhaps, we have  the  reason,  why
 the  greater number of the  viscera, receive the  impulse
 of the red  blood upon their concave surfaces, as may be
 seen  in the kidneys, the  liver, the  spleen, and the intes-
 tines.  By such  disposition, the  impulse of the  heart is
 less divided.*
   From  what  has  now been  said, we  may add  another
 reason to that which we  have before  given, for establish-
 ing  in what way  the functions  of  the animal  life are
 interrupted  from cessation of action  in the red-blooded
 heart.  We may  now also  begin  to  explain  the same
 phenomenon in the organic life.   The reason  of  such
 interruption in both the lives is the  same.  It is as fol-
 lows :
   1st. In the  case of death  affecting the red-blooded
 heart; the  intestine movement, which  proceeds  from the
 manner in  which the  arteries  are  distributed within the

  * It should not be lost sight of, that all this discussion turns upon the
application  of a principle which is by no means proved : viz. that  the
different organs, in order to exercise their functions,  require to be
agitated by a  partial or general motion.  We have  already made it
appear, that as it respects the brain, this jarring of the whole mass, to
which Bichat attributes so much importance, appears to be  a circum-
stance purely  accidental from the entrance of  the arterial blood.  The
same may be said of the  oscillatory motion produced in the other organs
by the pulsation of the ultimate arterial ramifications. 
198         PHYSIOLOGICAL RESEARCHES
 substance of all the organs, both of the one and the other
 life, is suspended ; hence there exists no farther cause of
 excitement for the organs: they must consequently die.—r
 2dly. The  causes of  the more  extensive and  general
 movements  of the organs are abstracted ;  for  almost all
 these causes  depend upon the brain.   We respire and
 move, only while the  brain is alive : but as the brain
 must be in a state of  collapsus, as soon as it ceases  to
 receive  the  impujse of its blood,  its  influence must  be
 evidently annihilated.
  Hence  it  follows,  that the  heart exercises over the
 different organs two  modes of influence ; the  one direct
 and immediate, the other indirect, and made through the
 medium of the brain, so that the death of the organs in
 consequence  of the death of the heart,  is immediate  or
 mediate.
  We have  sometimes  examples  of partial death, analo-
gous  to  this  sort of  general  death.  Thus,   when the
 circulation is impeded  in a limb, and  the  red blood no
longer distributed to its parts, such  parts become  at first
insensible and  paralytic,  then gangrenous. The  opera-
tion of aneurism furnishes us with too  many instances of
this  phenomenon, which by ligature,  may be produced
also  in.  the  living animal.   Undoubtedly the principal
cause of death in these  cases, is the want of that stimulus
 which it is the business of the particles of  the  red blood
to create, in contradistinction to those of the black blood
 but the absence of the intestine movement in question  is
 by no means a less real cause of such death.
  As for the  interruption  of  the nutritive process,  it
 cannot be  admitted  as a cause of the symptoms  which
 succeed  after  the  obliteration of a  large  artery.    The
slow, the gradual, and  insensible  way, in  which  this
 function  is performed,  does not accord with the sudden 
ON LIFE AND DEATH.
199
and instantaneous  production of those symptoms, especi-
ally as they affect  the animal life ;  for this is annihilated
in the limb at the very instant when the  blood ceases to
flow into it, just  in the same way as it is, when by  the
section of its nerves, the influence of the brain is  abstract-
ed.*
   Besides the preceding causes, which, when  the heart
is dead, suspend in general  the whole  of  the animal and
organic functions ; there  is another  cause of death which
especially affects the greater number of the latter, such
as  the  processes of nutrition, exhalation, secretion, and
therefore digestion, which is only performed  by means of
the secreted fluid.  This  cause of death to which I refer,
consists in  the necessary slop which is  put to these differ-
ent functions, in consequence of their no longer receiving
the materials upon which they  are exercised.   Neverthe-
less,  such  term arrives by  degrees only, because  they
receive  the materials on  which they act,  from the capil-
lary,  and not  from the  general  circulation.   Now  the
capillary circulation, is only subject to the influence of
the insensible  contractile powers of the parts in  which it
is performed; and  is exercised independently of the heart,
as may be  seen in the greater  number of reptiles, where
the heart may be  taken away, and the  blood  be  notwith-
  * When the passage of the arterial  blood to a muscle is  stopped, a
more or less complete numbness soon  takes place; and this effect is
too sudden to be attributed to the  want of nutrition ; and as certainly
it is not owing to  the want of agitation by the pulsations of the small
arteries ; for if, the artery is left free, and a ligature is applied upon
the vein, the pulsations are increased rather than diminished and yet the
numbness appears as quick as before.
  When  the  muscle has been a  long time without receiving blood,
gangrene seizes upon  it; and  this can  then be attributed, in great
measure, to the want of nutrition.  The diminution of the temperature,
which  necessarily takes place in an organ in which the blood is  not
renewed, must also contribute to this disorganization. 
200
PHYSIOLOGICAL RESEARCHES
 standing observed to oscillate for a long time afterwards
 in the minuter vessels.*  It is manifest, then, that what-
 ever quantity of blood is left in the  capillary system  at
 the period of the  death of  the  heart, will  for some time
 afterwards be sufficient to keep up the  functions in ques-
 tion,  and  that such  functions in consequence will only
 gradually cease.
   The following is a general view of the manner in which
 the annihilation of all the functions succeeds to the inter-
 ruption of those of the heart.
   The animal life is terminated—1st,  Because the organs
 of which it is  composed, are no longer excited without,
 by the  movement  of the neighbouring  parts, nor within,
 by the  blood.—2dly, Because the brain,  from  want  of
excitement, can no longer be a cause of excitement.
   The organic life is terminated—1st, Because, as in the
 animal life, there is a want of external  and internal excite-
ment  for its  different viscera.—2dly, Because there is a
 want of the materials on which its  functions are particu-
 larly exercised.
   There are a  number  of other considerations, however,
 besides those which we have mentioned, which prove the
 reality of the excitement of  the organs, from the  move-
 ment  communicated to  them  by the blood, as well as, th»
 reality of the cause, which  we have asserted to be that  of
 their death, when such excitement ceases.
   For,  1st.—The  organs which are  penetrated  only  by
 the serum of the  blood, such as the  hair, the nails, the
 tendons, and  cartilages, enjoy a less degree of vitality,

  * We know that the blood pushed into the arteries distends  the
 parietes of these vessels, and brings into action their elasticity; now,
 after the heart has ceased to act, these parietes, by contracting, can
 impart, for some instants, an oscillatory motion to the fluid contained
 in their cavity. 
ON  LIFE AND DEATH.
201
and a less energetic action, than those in which the blood
is made  to circulate, either immediately by the heart, or
by the insensible contractile powers of the parts them-
selves.
   2dly.—When  the  white  organs  are  inflamed,  they
receive an augmentation of life, a superabundance of sen-
sibility,  which frequently put them  on a  level in many
respects with those organs,  which in their  natural state
are endowed with  the highest degrees of life and sensi-
bility.
   3dly.—Those organs which habitually receive the influx
of the red blood, when inflamed, exhibit, in  every instance,
a local exaltation of the phenomena  of life.   In the two
preceding instances, it is true,  indeed, that the change of
vital powers, precedes in point of time, the change which
is made in the circulation ; the organic sensibility of the
part, has been  augmented  before the blood  is  carried
thither in greater quantity;  but afterwards it is the afflux
of such increased quantity of blood,  which keeps up the
unnatural action  which  has  been established.   A deter-
mined quantity of blood in the ordinary state of the part,
is necessary to the maintenance  of that state ; but when
the  part receives  a double or triple increase  of energy,
its excitant also  must  be doubled or  tripled ;  for in the
exercise of the vital powers,  there are always three things
to be remarked ; the power  inherent in the organ ; the
excitant which is foreign to  it; and the excitement which
is the product of the two.
   4thly.—It is doubtless, for this reason, that  the organs
io which  the  blood is habitually carried by  the  arteries,
enjoy a degree of  life, proportionate to the  quantity of
fluid by which  they  are  injected.  Such phenomenon
may be observed in the glans penis, in the  corpora cav-
ernosa, in the nipple,  in  the skin of the  face,  and the
              26 
204          PHYSIOLOGICAL RESEARCHES

actions of the brain, whenever the blood is directed with
impetuosity towards them.
  5thly.—The whole of the circulatory system, is thrown
into greater action from the exaltation of the whole  of the
vital phenomena, just in the  same way as the particular
circulation of any part is augmented, when the particular
phenomena of the life of that part are increased.   The
use of spirituous liquors, and spices to a certain quantity,
is followed for a time  by a general increase of energy in
the powers of the system.  The access of inflammatory
fever  will double and triple the intensity of life.
  In these considerations I have only regarded the move-
ment  which is communicated to the organs by the blood.
In another place I shall  call the attention of the  reader
to that species of excitement, which is produced by the
nature of the blood,  by the contact   of its  component
particles  when in a state of oxydation  or otherwise, with
the different parts of the body.  The reflections which I
have offered, will be amply sufficient to convince us how
much  the  blood, independently of  the materials which
it conveys with it, by its simple influx, is necessary to
the activity of the organs, and consequently how much the
cessation  of the functions of the heart,  must influence the
death  of the organs.
                   CHAPTER V.

OF THE INFLUENCE OF THE DEATH OF THE HEART AS TO
        THE  PRODUCTION OF GENERAL  DEATH.

  Whenever the heart  ceases to act, general death is
produced in the following manner :—1st. For want  of 
ON  LIFE AND DEATH.
203
excitement the cerebral actions are annihilated, and  con-
sequently an  end  is immediately put  to  all sensation,
locomotion, and utterance.   Besides,  for w7ant of excite-
ment on  the part of the  blood, the organs of these  func-
tions would cease to act, even  supposing that the brain
were to remain unaffected, and exert upon them its accus-
tomed  influence.   Thus the whole of the animal life is
suddenly suspended, and at the instant of the death of the
heart, the individual is dead to what surrounds him.
  The interruption of the  organic life, which  has com-
menced by the death of the heart, is produced at the same
time by  that  of the lungs.  The brain  being  dead, the
mechanical functions of the lungs must cease: the chemi-
cal functions of the lungs must  cease also, for want of
the materials  on which  they are exerted: the latter are
directly interrupter], the  former through the medium of
the brain.
  After this the progress of death is gradual.  The secre-
tions, the exhalations, the nutritive actions are put an end
to.   The latter are first arrested in  those organs which
receive the more immediate impulse of the blood, because
in these, such impulse is necessary to the performance of
the functions.  The paler organs are less dependent on
the influence of the heart, and consequently must be less
affected by the cessation of its action.*
  In the successive termination  of the latter phenomena
of the  internal  life, the vital powers  continue to subsist
for some time after the  loss of the  functions :  thus, the
organic  sensibility, and  the sensible  and  insensible  con-

  * Life is so obscure in the tendons, ligaments, &c. that it is impossi-
ble to fix the moment when it ceases in these parts.   How then has
Bichat been able to compare the quickness of  their death with that of
the other organs ? Upon what data has he been able to determine that
!t takes place more slowly ? 
204           PHYSIOLOGICAL  RESEARCHES
 tractilities survive the phenomena of digestion, secretion,
 and nutrition.*
   The vital  powers  continue  to  subsist  in  the internal
 life, even when the corresponding powers of the animal
 life, have  suddenly become extinct : the reason is plain  :
 the  power of  perceiving and  moving organically  does
 not suppose  the existence of a common  centre ; for the
 animal perceptions and motions,  the action  of the brain
 is requisite.
   The phenomena of death  are concatenated  in the above
 order in  all  aneurismal  ruptures, in all  wounds of the
 heart  or  larger vessels, in  all  cases of polypi  formed in
 the  cardiac cavities,t of ligature artificially applied, of
 compression  exercised  on   the parietes of the heart by
 humours, abscesses, &c. &c.
   It is in this manner also that we die  from  sudden affec-
 tions of the mind.  The news  of a very joyful, or a  very
 melancholy event, the sight  of  a  fearful  object,  of a
 detested  enemy, of  a  successful  rival, are  all of them
 causes  capable of producing death.   Now  in all  these
 instances, it  is  the heart,  which is the first to die, the
 heart, whose death  successively produces that of all the
other organs, the heart, on which the passion is exerted.
  *The secretion of mucus, the  growth  of the nails, the beard and
 the hair often continue on the dead body long after the last traces of
 irritability have disappeared  in the muscles of locomotion, in the  fleshy
 coats of the intestines, &c.
  t Since more care has been taken in examining the lesions of different
 organs in post mortem examinations, there is no longer found  those
 fatty polypi, which were formerly  considered as causes  of death.   It is
 probable that those yellowish concretions of albuminous matter which
 are found between the pillars of the auricle, and which seem to be fixed
 there, were mistaken for  polypi.  There is sometimes found in  indi-
 viduals formerly affected with the venereal disease, vegetations near the
 valves; but these  productions are commonly too trifling to oppose the
 expulsion of the blood contained in the cavity. 
0N LIFE AND DEATH.              205
   And  hence we are led to some considerations on syn-
cope, an affection exemplifying in a less degree the same
phenomena, which in a greater one, is offered us in cases
of sudden death.
   The causes of syncope  are  referred  by Cullen to two
general heads : Of these there is one set which according
to him affect the brain, another set which affect the heart.
Among the first, he places the more violent impulses on
the mind, and  various evacuations, but it is easy to prove,
that the brain  is only secondarily affected in  syncope pro-
duced by passion, and that it is the heart, whose functions
in all these cases are the first to be interrupted.  The
following  considerations, if I am not mistaken, will  leave
but little doubt on this head.
   1st.—I  have proved, in speaking of the  passions, that
they never affect the brain  in the  first place ;  that the
action  of  this  organ, in consequence  of their develop-
ment, is only secondary, and that every thing relating to
our moral affections has its seat exclusively in the organic
life.
  2dly.—The phenomena of syncope when produced by
lively emotion, are similar  in  every respect to  tljose of
syncope, the effect of polypi or dropsy of the pericardium,
but in the latter, the affection of the heart, is the  primary
one, and should in consequence be the same in the former
sort of syncope.
  3dly.—At the moment when  syncope takes place, we
feel the attack at the heart, and not in the brain.
  4thly.—In consequence of lively passions, which may
have occasioned syncope, we find that  the heart and not
the brain becomes diseased, nothing  is more common than
organic  affections of the  former from sorrow. &c.  The
different sorts  of madness,  which  are produced by the
same cause,  for the  most part, have their principal scat in 
206           PHYSIOLOGICAL RESEARCHES
some of the viscera of the epigastrium, and in such case,
the irregularity of  the cerebral action is  the sympathetic
effect of the profound affection of the internal organ.*
   5thly.—I shall prove hereafter, that the cerebral system
does not exert any  direct influence over that of the circu-
lation ;  that there is no reciprocity  between the two,  and
that the changes of the first are not followed  by similar
changes in the second, however much the changes of  the
second may  modify the first.   Destroy all nervous com-
munication  between  the  brain and the  heart,  and  the
circulation will go on  as usual; but if the vascular com-
munications  be intercepted, the  cerebral  action  vanishes
at once..
   6thly.—Palpitations and other irregular movements of
the heart are  often  the effect  of the same causes, which

  *The singular idea of placing the  seat of madness in the viscera of
the abdomen,  arose at a period when a  certain number of mystical
ideas formed the basis  of all physiology.  The  four sorts of humours
performed in the human body (microcosm) a part as important as the
four  elements  did  in the whole universe (macrocosm.')  The bile, the
blood, the pituitary and  atrabiliary fluids  determined, by their predomi-
nance the different temperaments, and produced the different diseases.
The atrabiliary humour was, as is well known, thought to be the cause
of melancholy and mania ;  now this humour was  said to be secreted
by the supra-renal capsules, and the  position of these organs no doubt
gave the  name of hypocondria,  which is  given to  a certain  degree of
mental alienation.
  After a great number of ages, the  mysterious properties of numbers
are almost entirely out of favour.  We still speak of the four tempera-
ments, but attach no importance to the four  ages of man or to the  four
parts of the day.  We recognize in  the  human  body more  than  four
kinds of fluids, but among them all we do not find the atrabiliary fluid.
The cause of madness then  cannot be attributed to this humour, and
yet we dare not drive this disease from the seat it has so long held.  In,
order to find reasons for keeping it there, they seek in the  viscera for
disorders which  are not often found there  even in the most striking
cases, and which most often still exist without the least alteration in the
intellectual functions. 
ON LIFE AND DEATH.
207
in some individuals are the occasion of syncope.   In such
cases, it is easy to discover the seat of the affection, and
such  smaller effects  of the  passions  on  the heart, are
very  well calculated to throw light upon the nature of the
greater.*
   From these many considerations, we may conclude that
the primitive seat of  the attack  in syncope, is the  heart,
which  does not cease  to  act, because the action of the
brain has been interrupted, but because it  is the nature of
some of the passions in such way to  affect it, the brain
at the same time,  suffering a temporary death, because it
no  longer  receives the fluid, which  is necessary  to its
excitement.  The nature of syncope is well enough illus-
trated, by the vulgar expression of being  sick at heart.
   It is of no importance to our present purpose, whether
syncope depend on polypi, on aneurism, or be the result
'of some violent emotion.  Thesuccessive  affection of the
organs is always the same.  They die for  the moment in
the same way, as they really perish  when  the  heart  is
wounded, or a ligature put upon the aorta.   In the same
manner also  are  those sorts of syncope produced,  which
succeed after any great evacuation of blood, pus  or water.

  * We should be often exposed to commit great mistakes, if we always
judged by this rule.  The sensation is a very uncertain means of deter-
mining the organ that is  primarily affected ;  this can be  proved by
numerous examples, we shall cite one only which relates to the brain.
Nausea and vomiting are  often, as is well known, among the first
symptoms of cerebral affections ; should we from this believe that the
seat of the disease is in the stomach ?  Undoubtedly  not: now,  in
syncope produced by a strong affection of the mind,  there is no reason
to suppose that the heart is affected before the brain, since the intel-
lectual phenomena have  necessarily preceded  the  sensation of joy or
Of sorrow which has produced the syncope. But to say that the brain
was primarily affected, is not saying that its action ceased before that of
the heart; and every thing, on the contrary, leads to the belief that the
loss of the senses t? a consequence of the suspension of the circulation. 
208          PHYSIOLOGICAL RESEARCHES
 The heart is affected from sympathy, the  brain for want
 of its excitant.*
   Those cases of syncope which are occasioned by pecu-
 liar odours, by antipathies, &c. appear also  to be attended
 with the  same progression  of  symptoms, though their
 character be much less easily understood.  There is a great
 difference  between syncope, asphyxia, and apoplexy, in
 the first it is by the heart, in the second  by the lungs, in
 the third by the brain that begins the general death of the
 body.
   Death, as it happens in consequence of  disease, in gene-
 ral  exemplifies a concatenation of  these  different symp-
 toms.  The  circulation,  respiration, or  cerebral action
 cease, the  other  functions are  afterwards  interrupted of
 necessity, but in these  sorts of death, it rarely happens
 that the heart is the first to die.   This however is some-
 times the  case.   After long  continued.suffering, great
 suppuration,  and  sometimes, in  dropsy, certain fevers,
 and gangrenes, one fit of syncope comes on after another,

  *The syncope is produced in this case, from the sudden  change in
the circulation of the brain.  But this  change varies  according to the
seat of the effusion.  If it be in the peritoneal cavity, the pressure that
it makes interrupts the circulation in all  the organs  contained in the
abdomen ; the descending  aorta is  found compressed, and the blood,
forced back towards the superior parts, accumulates in the sinuses and
vessels of the brain.   If  the fluid  be evacuated by puncture, the
equilibrium is re-established in the different parts of the  vascular sys-
tem, the blood enters vessels which were before closed  to it, it abandons
in part those of  the brain, and it is  this sudden change in the circula-
tion of the organ which produces syncope.  If, on the contrary, the
effusion be formed between the two  layers of the arachnoides, and we
can, as in spina bifida, evacuate the fluid by puncture, the vessels of the
brain are immediately relieved of the pressure to which they had been
subjected, and the blood, which before was  forced back, towards the
inferior parts, is  driven forcibly into them ;  the change is, as must be
perceived, the reverse of the  preceding; but the result is the same, and
ryncope is produced in this rase as in the other. 
ON LIFE AND DEATH.
209
 at  last a longer  one succeeds, and  the patient dies, but
 whatever  be the part affected,  whatever  the diseased
 viscus or organ, whenever the phenomena of death com-
 mence by the heart, they succeed each other as we have
 described them to do in sudden death, from lesion of that
 organ.   In other cases, the heart is the last to act, is the
 ultimum moriens.
   In general, in  morbid affections, we much more  com-
 monly observe the  ingress of death  to be made by the
 lungs, than either by the heart, or the brain.
   Whenever disease is terminated by syncope, the lungs
 are found to be almost empty, and if  not  affected by any
 organic disease, are  collapsed, occupy a part  only of the
 cavity of the thorax, and are  of their natural colour.
   The  reason of this  anatomical fact is simple.   The
 circulation which has been suddenly interrupted, has not
 had time to fill the vessels  of the  lungs, as happens when
 death begins, by  affecting  the lungs or the brain.   The
 truth of this fact I can  vouch  for,   having  frequently
 ascertained it by  dissection, and  in  general, as often  as
 death commences by the heart, or the larger vessels, such
 vacuity of the lungs may be considered as universal.
  I have remarked it in the bodies of persons who  have
 died from  great  hemorrhage from wounds or aneurismal
 rupture and violent passion, as well as in those  who have
suffered by the guillotine.   The same phenomenon  may
be seen, by inspecting the  lungs of any animal, which is
killed in our butcheries.
  In killing the animal slowly by the lungs, that organ
might be filled with blood.  Its taste would then be dif-
ferent from that which it naturally possesses, and resem-
ble that  of the spleen.  Our cooks  know well  how  to
take advantage of that state of infiltration in which the
latter viscus is generally found.
              27 
210
PHYSIOLOGICAL RESEARCHES
                   CHAPTER VI.

OF THE INFLUENCE OF THE  DEATH OF THE  LUNGS OVER
                THAT OF THE HEART.

  We have already said, that the functions of the lungs
are of two kinds,  mechanical  and  chemical.  Now the
activity of this organ  ceases sometimes  by the former,
and sometimes by the latter  of these functions.
  Any wound, which  exposes  the  lungs on  both sides,
for a considerable extent, occasions their sudden collapse;
any division of the spinal marrow, which suddenly para-
lyses  the intercostals, and  the diaphragm ;  any  very
strong compression  exerted  at the  same time upon the
whole  of the thorax,  and the parietes of the abdomen,
any sudden injection of a large quantity of fluid into this
cavity, are all of them causes which begin the death of
the lungs, by putting an end to their mechanical functions.
Those which  influence in the  first  place their chemical
functions, are  the different sorts of asphyxia, strangula-
tion,  submersion,  and a vacuum,  in whatever  manner
produced.

I. In what manner is the death of the heart occasioned
  by the interruption of the mechanical functions of
  the lungs'.

  The interruption of the  functions of the heart, can
only succeed in two ways to that of the mechanical func-
tions of the  lungs : 1st.  Directly, because a  mechanical
impediment is put to the circulation of the  blood,  by a
state of collapse in the lungs.   2dly. Indirectly, because 
ON LIFE AND DEATH.
211
 in such state the lungs no longer receive the materials,
 upon which  their  chemical  functions are exerted, and
 therefore cannot transmit them to the heart.
   Physiologists have all of them admitted the first  mode
 of interruption, in the  Pulmonary circulation.   Reflected
 on themselves, the vessels of the lungs have not appeared
 to them,  to be capable of  transmitting the blood, on
 account of the numerous angles which they make.  This
 idea they have borrowed from the phenomena of hydrau-
 lics, and it is their reason for the death which ensues, in
 consequence of a too long continued expiration.
   Notwithstanding all which, it has  been  proved  by
 Goodwyn, that in such case there remains a sufficient
 quantity of air in the air vessels, for dilating them enough
 to allow of the  mechanical passage of the  blood ;  he
 proves in consequence, that  an unnatural permanence of
 the state, in which the lungs are  placed  from the  act of
 expiration, does not affect the blood in the way, which is
 commonly  believed.  This is one step towards the truth,
 but we shall  approach it much more nearly, and even
 attain it, should we be able  to prove, not only that there
 remains a  sufficiency of air  in the  lungs  to permit  the
 transmission of the blood, but that the very folds pro-
 duced  in the vessels by a state of collapse in the organ
 are not a real impediment to its course.   The following
 observations  and experiments  will  assuredly determine
 this fact.
   1st.—I  have already proved, that a state of fulness or
emptiness in the stomach, and in all the hollow organs in
general, produces no apparent change in the state of their
 circulation; and  that  the blood  in consequence, will
traverse the x^essels, when bent or  doubled upon  them-
selves, as  easily, as when  they are distended in  every
direction.   For what  reason  should a  different effect be 
212            PHYSIOLOGICAL RESEARCHES
produced  in the  lungs,  by the  same  disposition of  the
parts ?
   2dly.—There  are  different vessels  in  the oeconomy
which  we  may alternately bend or extend at pleasure :
such are those of the mesentery,  when exposed  by  an
incision into  the  abdomen of  the  animal.   Now in this
experiment, which has been already made to prove the
influence of the tortuous  direction of the arteries upon the
mechanism of their pulsation, if one of the mesenteries
be  opened, and then  either  bent or extended, in  either
case the blood will be thrown out  with the same degree
of  violence, and in equal times  will  be emitted  in equal
quantities.   I have always obtained the same result in this
experiment which  I  have many times  repeated.   From
analogy we might expect the same from  the vessels of
the lungs ;*  and from  the following experiment it may be
proved.

  * It is not because the vessels of the lungs have become tortuous that
the blood flows through them with difficulty, but because they are com-
pressed.   It was  needless for Goodwyn  to seek for  reasons to prove,
that the flattening of the lungs does not  offer a mechanical obstacle to
the course of the blood.  If he had observed with attention the phe
nomena of respiration, he would have seen that this contraction, if it
does not completely interrupt  the circulation of the blood in the lungs,
at least modifies it in a very remarkable manner.   When the lungs con-
tract, not only the bronchial cells are flattened, but the pulmonary
vessels are compressed, and tend to expel the blood contained in their
cavity.  This fluid flows back then on one part  towards the right ven-
tricle by the pulmonary artery, and on the other it accumulates in the
pulmonary veins before entering the left auricle.  Hence we see that
the jet by the carotid artery must increase  rather than lessen in the last
moments.  But if the compression continues, as the capacity of the rami-
fications of the  pulmonary artery is diminished as well as that of the
veins of the same name, the quantity of  blood which passes through the
lungs is  less, and the jet by the  carotid necessarily decreases.  The
experiment related by Bichat is then entirely opposed to the  opinion
*hich he advances. 
ON LIFE AND DEATH.
213
   3dly.—Take a dog, cut the treachea, and adapt the tube
of an  injecting syringe to it, then make a vacuum  in  the

   It is not only by influencing the course of the blood in the system  of
pulmonary vessels that the alternate motion of the thorax modifies the
circulation.   If we lay bare the jugular veiu of a dog, we perceive  that
the blood does not move in its cavity from the  sole influence  of the
right auricle, but in an evident manner from the influence of the motions
of respiration also.
   At each time  that the thorax is  dilated in inspiration, the vein  is
quickly emptied, flattened  and its  parietes   are  sometimes  hi-onght
exactly  against each other; it swells on the contrary and fills with blood
when  the thorax contracts.   A similar phenomenon takes place  in the
venae  cavae.   In order to render it evident it  is sufficient to introduce
by the jugular vein into the vense cavae a sound of gum elastic ; we then
see that the  blood flows through the extremity of the sound only during
the time of expiration.   A similar effect is observed if we  introduce a
sound into the crural vein and direct it towards the abdomen.
  Haller and Lorry have  paid much attention  to this phenomenon, and
have proposed an explanation of it  which seems very satisfactory  at
first view, though it is  really imperfect.   When  the thorax is dilated,
say they, it  draws the blood from the venae cavae, and, by degrees, that
of the veins  which are near it.   The  mechanism of this inspiration is
very similar  to that by which the air is drawn  into the trachea.   When
the thorax contracts, on  the contrary, the blood  is crowded  back  in
the venae cavae by the pressure which is made  on all the pectoral organs,
vessels,  heart and lungs, by  the  expiratory  powers, and  by  degrees
arrives at the veins which terminate  in  them.  Hence  the alternation
of vacuity and fulness which the jugular veins exhibit.
  If we open an artery,  and examine with attention the jet of blood,
we see  that it increases in  expiration,  and this is especially  evident
when  the animal expires strongly or makes an  effort;  but as we cannot
always produce these efforts at will, or a great inspiration, we can  in
some  measure imitate the phenomenon and produce the contraction  of
the lungs by compressing with the hands the  sides of the thorax; we
i=ce then the jet of arterial blood increase or diminish, in proportion  to
the pressure  that is made.  If respiration  produces this effect on the
course of the blood in the arteries, it is natural to think  that  it  can
influence the course of the venous blood, not.only by means of the veins,
as Haller and Lorry thought, but also by means of the arteries.  For the
purpose of satisfying myself, I made the following  experiment,  I  tied 
214           PHYSIOLOGICAL RESEARCHES
 lungs,  and  cut  the  carotid  artery.    It  is  evident, that
 according to  the  common  belief4,  the circulation should
 be immediately  suspended,  in  this experiment,  since the
 pulmonary vessels from  their ordinary state of distension,


 the jugular vein of a dog; the vessel became empty below the ligature,
 and swelled much above, as uniformly happens.  I punctured slightly
 with a lancet the distended portion, so as to make a very small opening.
 I obtained in this way a jet of bl"od, which  the ordinary motions of
 respiration  did not modify evidently,  but whioh trebled or quadrupled
 in size if the animal made any considerable effort.
   It might be objected, that the effect of respiration was not trans-
 mitted by the arteries to the  open vein, but  by the veins which were
 free, and which would have  transmitted the  blood  of the venae cavae,
 towards the tied vein, by  means of anastomoses.  It is easy to remove this
 difficulty; in fact,  in the  dog the internal jugular vein is, as it were, but
 the appearance of a vein, and the circulation of the head and neck is
performed almost entirely by the external jugular veins, which are very
large.  By tying at the same time these two veins I was sure of prevent-
ing, in a very great measure, the reflux which has just been spoken  of;
but so far from the double ligature diminishing the phenomenon before
stated, the jet  becomes on the contrary more  strictly  in relation with
the motions of respiration, for  it  was evidently modified, even by com-
mon respiration;  which,  as we have seen, does not happen  in the case
of a single ligature.  In order to  render the thing more evident, I tried
it on the crural vein; this vein and all its branches being furnished with
valves, which oppose a  reflux, if this phenomenon  of the increase of
the jet appears during expiration, we might be sure that the impulse
came from the  arteries.   This  is  what I have observed in fact in many
experiments.  The crural vein  being tied  and punctured  below the
ligature, the jet which is  formed increases evidently in powerful expira-
tions, ;n the efforts  and  the  mechanical compressions of the parietes
 of the  ihorux with the hands.
  We see by this and the preceding experiments, that we cannot adopt
without modification the  expression of Haller and Lorry relative to '.he
swelling of the vein". This  swelling takes place,  not only, as they
say, by the  flowing  back of the blood of the venae cavae  into the
branches which open into them  mediately  or immediately, but also by
the entrance into the vein of a greater  quantity of blood coming from
 the arteries. 
ON LIFE AND DEATH.
215
must  have passed to the  greatest possible  degree of col-
lapse,  in  consequence of the  total  abstraction  of air;
notwithstanding which the blood will  be violently thrown
out  from  the divided arteries for a certain time, and must
consequently traverse  the lungs :  it will afterwards cease
by degrees, but this,  from  causes which I shall  explain
hereafter.
   4thly.—The same effect may be  produced  by opening,
on both sides, the  breast of  a living animal,  because  the
warm and rarified air  of the  lungs,  will  be  more than
balanced by the pressure of the colder air without;* now,

   * As in dead bodies the air within and the air without are of the same
temperature, the lungs, when they are full of it, do not flatten when the
thoracic cavity is  opened.   There is usually then a space between the
parietes and the contained organs; this is not because we die in expira-
tion ; for as the lungs empty themselves, the ribs and intercostal muscles
rest upon them ; it is  because the pulmonary air, in  cooling occupies
less space, and the cells contracting gradually as the cooling takes place,
diminish the whole size of the organ.  A vacuum is then made between
the pectoral and pulmonary portions of the pleura.
   It is thus that, under some circumstances, the brain flattening and
lessening after death, whilst the cavity of the cranium  remains the same,
a vacuum  is formtil between these  two parts, which then exhibit an
arrangement different  from that of the living organs.   If the sacs with-
out an opening, as the peritoneum, tunica vaginalis, &c. never resemble,
in this respect, the  pleura and arachnoides; if their different surfaces are
always contiguous after death, it is because the  abdominal parietes or
the skin of the  scrotum, unable to resist the external air, flatten by
pressure, and are brought against the internal orgaus,  as the diminution
of these tends to form a vacuum.
   It is to this  vacuum existing  in the pleura of dead  bodies, that must
be referred  the following phenomenon, which is always  observed when
the abdomen is opened and the diaphragm  dissected.  In fact, as  long
as no opening is made in this muscle, it remains distended and concave,
notwithstanding the weight of pectoral  viscera  which  rest upon it in
a perpendicular situation, because the  external air, which presses  the
concavity of it, forces  it then into the  vacuum  in the thorax, which
never exists during life.  But the instant the air is admitted by a cut of 
216           PHYSIOLOGICAL  RESEARCHED
 neither in this  case does the circulation  experience any
 sudden  change.   For  the  sake  of greater  exactness, the

 the scalpel, this  muscular partition flattens, because the equilibrium
 is established.  If all the air is drawn from the lungs by a syringe, the
 diaphragmatic arch  is still more evident.
   There is then this difference between the opening of a dead body and
 that of a  living one, that in the first the lungs are already flattened, and
 in the second they flatten at the instant of opening.  The contraction
 of the cells, from the condensation of the air by cooling, is an effect of
 the contractility  of texture or from want of extension, which as we
 have said, continues in  a degree with the organs after death.
  Besides, if the lungs  flattened in  the dead body the instant the thorax
 was opened, it  would be owing  to the pressure of the external air, a
 pressure which would  expel through the trachea what was  contained
 in these organs.   Now  if, to prevent the escape of air, you close her-
 metically the canal  by  fixing a tube to it the stopper of which is tight,
 and the thorax is afterwards opened, the lungs still flatten ; the air had
 already gone out of them.  Make, on the contrary,  the same experi-
 ment on a living animal, you will always prevent the flattening of these
 organs, by preventing the expulsion of the air.
  In this  point of view Goodwyn has gone on a wrong principle  in
 measuring in a dead body, the quantity of air  remaining in  the  lungs
 after each expiration.  Besides, if you open  bodies ever so little, you
 will hardly find  two in which there is the same arrangement in the
 lungs.   The infinitely various manner in which life terminates, by accu«
 mulating more or less blood in these organs, by retaining more or less
 air in them, &c. gives them so variable a size, that no general data can
 be established  respecting them.  On the other  hand, can we hope  to
 be more successful on the living body ?  No ; for who does not know
 that  digestion,  exercise, rest, the passions, tranquillity of mind, sleep,
 watchfulness, temperament,  sex, &c. make  an  infinite variety in the
 forces of the lungs, the  rapidity with which  the blood circulates through
 them, and the quantity of air that  penetrates them ?  All the calcula-
 tions on the quantity of this fluid which enters or goes out according to
the inspiration  or  the   expiration,  appear to me to be physiological
errours, inasmuch as they assimilate the nature of vital forces  with that
of physical forces.   They are as useless to science as those which had
formerly for their object the muscular force, the  velocity of the blood,
 &e.  Besides, observe if their authors agree  better among themselves
 then they used to do on this much agitated point. 
                   ON LIFE AND DEATH.              2\1

 little  air remaining  in  the cells  of the  organ  may be
 voided by a syringe.
   Along with  these observations  let us place the facility
 with  Which  the  pulmonary  circulation continues  to be
 made, when collections of water, pus, or blood, are lying
 within the pleura,  or  pericardium.   In these  cases the
 air vessels are often  prodigiously contracted, and conse-
 quently the vessels of their  parietes  doubled and bent.*
 If  this state  be  taken into  consideration, we shall  have
 sufficient data for concluding that the tortuous disposition
 of  the vessels, can never be  an obstacle to the passage of
 the blood; and  therefore, that  the  interruption of the
 mechanical functions of  the lungs, can never directly put
 a stop to  the action  of the  heart, though  it  may do so
 indirectly, in  impediiig the  exercise  of  the chemical
 functions of the  lungs.
   If then  we  can  determine  why  the  heart  remains
 inactive,  when the latter phenomena  are  annihilated, we
 shall have  resolved a double question.
   Many  authors have  asserted   that the  death, which
 ensues after a too long continued  inspiration, is owing to
 the  mechanical distension of the -pulmonary vessels  by
 the  rarified air, a distension  impeding the  circulation.
  * It is inconceivable how Bichat could think of confirming his opinion
by the example of hydrothornx. Who does not know that when an
effusion takes place in the cavity of one of the pleuras, that ttat portion
of the lungs  only which  is above  the level of the water  serves the
 purposes of respiration ; that when the effusion has arrived to the sum-
mit of the cavity, the lungs of that side, which  can no longer dilate,
are of no use in respiration ;  and those of the other,  being compelled
alone  to make  the necessary modifications  in the blood, must be
traversed by the greatest part of this fluid ?  It is known, finally, that
in this case the patient cannot lie down an instant on the sound side,
because this  position prevents the dilatation of the  lungs of that side
which alone  serve  for respiration, and the danger of suffocation is
therefore imminent.
                    2S 
 218          PHYSIOLOGICAL RESEARCHES

 But this reason also is  as  false a one, as that which  we
 have already disproved.   Inflate the lungs  as powerfully
 as may be, then tie the  trachea and open the carotids, and
 the blood will flow as impetuously, as when the respira-
 tion was perfectly free.*

 LI.  Why does the heart cease to act, when the chemical
        functions of the lungs are interrupted.

  According to Goodwyn, the  reason  why the contrac-
 tions of the heart are stopped, when the chemical func-
 tions of the lungs have  ceased to  be performed, consists
 in the want of  that excitement which the red blood only
 can produce upon the red-blooded ventricle.   This ven-
 tricle, says he,  has not  a sufficient  stimulus in the black
 blood, and death  is occasioned because  it no longer is
 capable of transmitting  any thing to the different organs.
 In this case death must  happen, as it would from ligature
 of the aorta—precisely in the same way as  when  its
 source is exclusively in the heart.  • The  other parts die
 only for want of blood, just as when in  a  machine, the
 principal spring  being  taken away, the others cease to
 act, because they are not put into action.
  On the contrary, I am persuaded that there  is a general
 affection of all the parts, whenever the chemical functions
 of the lungs are  suspended ; I  am  persuaded that  the
 black blood continues to be pushed on for some time by
the aorta, and that its influx into the organs is  the occa-
 sion  of their death ; that  the  organs die in  fact,  not
 because they do  not receive blood, but because they do
 not receive red blood; in a word, that they are penetrated
  * The observation of Bichat is very just; and" I have myself often
 observed in cases of apoplexy, that the motions of the heart continue
many hours after the arteries contain only black blood. 
ON  LIFE AND DEATH.
219
by the material  cause of  their death ; so much so, that
wo may asphyxiate any isolated part at will, by injecting
it with venous blood  while  all the others shall continue
to receive the red blood of the heart.  At present I shall
inquire  into  the  phenomena of the contact of the black
blood with  the  parietes  of the ventricle,  and refer  the
reader to the following chapters, for its  effects upon the
other parts.
  The movements of the heart may  be stopped and made
to cease altogether from the influence of the venous blood
in two ways.—1st. As Goodwyn has said, because  the
left ventricle is  not excited by it upon  its internal sur-
face.—2dly.  Because such  fluid, when  carried  into  the
substance of  the heart by the  coronary vessels, must act
upon  the muscular fibre of the heart in  the same  wray as
it does upon  the other muscles.  Now, for my part, I am
assured  that the  black as Well  as the red blood, will excite
into contraction the internal surface of the aortic ventricle.
The  following observations  and experiments will confirm
my assertion.                               .
  1st. If asphyxia were  to be followed by  the conse-
quences which Goodw)rn has supposed, it should influence
the heart in the  first place; the annihilation of the func-
tions  of the  brain, as in syncope, should be only secon-
dary ; nevertheless, asphyxiate an animal, by stopping up
the trachea, by placing him in a vacuum, by opening the
chest, or plunging him into carbonic acid gas, and it will
in every instance be observed, that his animal life is the
first to be interrupted, and that the creature externally is
dead ; but that within the heart continues for  some  time
afterwards to act, and the pulse to be felt.
  In  this way the symptoms of asphyxia are not  the
symptoms  of syncope.   In  the  latter  the cardiac and
cerebral actions are suspended at the same instant, in the 
220          PHYSIOLOGICAL RESEARCHES

former  the  heart survives, as in cases of strong concus-
sion of the  brain for many seconds.   It follows, that in
asphyxia, the different organs do not cease to act, because
the heart has ceased  to  supply them with  blood,  but
because it no longer supplies them with that sort of blood
by which they can be stimulated.
  2dly.  If the  trachea of an  animal be stopped, and an
artery opened, the colour of the  blood  which  it emits,
will gradually be changed, and at last become as black as
that of venous  blood.   Now, notwithstanding this phe-
nomenon, which is as  apparent as it can  be, the fluid for
some  time afterwards is thrown out full as strongly as it
would be, were it red.  I have seen a quantity of black
blood discharged in this way, more than sufficient to  kill
the creature from haemorrhage; were it not already dead,
in consequence of its asphyxiated  state.
  3dly.  In the last-mentioned experiment, it may, indeed,
be. alleged,  that some remains  of air in the air  cells,
might, as long as the black blood continued  to flow, have
communicated to it a principle of excitement; but to  put
it out of all  doubt, that the venous blood does really pass
into the aortic ventricle, unaltered in  its passage from the
corresponding cavity, the air may be entirely pumped out
of the lungs with  a syringe, by exposing the trachea, in
the first  place,  and then adapting the instrument to  the
transverse section of the tube;  after this, let the carotid
be opened ;  now as soon  as the red  blood  contained in
this artery is exhausted, the black blood will succeed to
it, and  that, without undergoing a variety of gradations
in colour ; in this case also  for a time, the jet will  be
very powerful, and only be  gradually weakened ; but if
the black blood were not an  excitant to  the  heart, its
interruption should be immediate. 
ON  LIFE AND DEATH.
221
   4thly. The  following  is another  proof of  the same
 nature.  Expose the breast on one side by sawing exactly
 through the  ribs before and behind :  when this is done,
 the lungs  on that  side will collapse.    Proceed to open
 one of the pulmonary veins; fill a syringe warmed to the
 temperature  of the human  body with venous blood,  then
 push  it into  the red-blooded  ventricle.   Now, according
 to the common opinion upon the subject of asphyxia, such
 fluid  should  at  least diminish  in a sensible  way,  the
 movement of that cavity, notwithstanding which, in four
 successive experiments,  I  could not  observe any  such
.diminution.   On the contrary, in  one of them, on push-
 ing the piston, the strokes  of the heart were  augmented
 in number.
   5thly. If the  black  blood  be not  an excitant  to the
 heart, it can  only want such  power, because  it contains
 more carbon and hydrogen, than the red blood ;*• but if
 the heart of  an- animal, which has been  killed expressly
 for the  experiment, by lesion of the brain or of the lungs,
 has ceased to beat, it may, notwithstanding, be made to
 contract as long as  it preserves its irritability,  by  throw-
 ing into  the aortic  ventricle  either hydrogen gas,  of
 carbonic acid gas.  It follows, that neither hydrogen gas
 nor carbon can act  as sedatives to the  heart.
   The experiments which I made and published last year,
 on the emphysemata, produced in  different animals  with
 these gases, have established the same truth with respect
 to the muscles, since they do  not cease to  move in  con-
 sequence of such experiments, and after death, preserve
 their  irritability as they usually do.

  * At the period Bichat wrote, it was impossible to know whether the
 arterial or venous blood contained most hydrogen and carbon.  At the
 present day even, when the means of analysis are much  more perfect
 and animal chemistry farther advanced, we are hardly better informed. 
222          PHYSIOLOGICAL RESEARCHES

   Lastly. I have  often  succeeded in re-establishing the
contractions of the heart, which have been annihilated in
different sorts of violent death, by the injection of black
blood into the red-blooded cavities, with a syringe adapted
to one of the pulmonary veins.
   Thus  it is proved,  that the red-blooded  heart does
actually push the black  blood into all'parts of the  body;
and in this way is the colour given  to  the different  sur-
faces, of which, in one of the following chapters, I shall
offer a sketch.
   Neither  does the  simple presence of the black blood
act in a more sedative way upon the  internal surfaces of
the arteries.*  If, in fact, while the tube adapted  to the
trachea is shut, the blood be made to flow from an artery of
the foot, it will be thrown out for some time, with the same
force which it would have been, were  the pipe to be open.
The action, then.,  which it  exercises in its passage from
the heart,  upon  the parietes of the  arteries, does  not
diminish the energy of these parietes.  When this energy
decreases, it  is at least in part from  a  different cause.
   From  the above  experiments we may conclude,  that
the black blood  arriving in mass at the red-blooded ven-
tricle,  and correspondent arterial system is able, from its
sole  contact  with  them, to occasion  the action of these
cavities; we maybe equally certain, that were  not the
functions of these  parts suppressed from other causes, the
circulation would  continue  to  be made in a very- sensible
manner,  at least, if not  with  force.
   Of what nature, then, are  the causes which  interrupt
the circulation in  the heart  and arteries when they are

   *It seems that when Bichat wrote this work, he had not fixed in his
own mind what part the  arteries take in the  circulation ; at least, in
this paragraph, he seems to give  them a contractile power, which, in
his other works, he accords only, to their ultimate ramifications. 
                ON LIFE AND DEATH.             223
                                              i
supplied with  venous blood ? for when  this has  been
flowing for some time^ the jet of it is gradually weakened,
and ceases at last entirely ; yet if the cock of the pipe be
opened, it will be  restored with vigour.
  I am persuaded that the black blood acts upon the heart
as it does on all the  other parts, as we shall see that it
affects the  brain—that it affects the voluntary muscles,
the membranes, and the  system in general ;  the tissue of
which it penetrates and  operates within it as a debilitant
upon each individual fibre.   I am fully of opinion, that
the circulation  would be almost as quickly interrupted as
in the preceding cases,  were it even  possible to  supply
the coronary arteries of the heart with red  bloody while
the.black blood is transmitted to the Various parts of  the
bod)' by the aortic aUriclc  and ventricle.
  The black blood operates by its contact  with the fleshy
fibres, at the extremity of the arterial system and not by
its contact with the  internal surface of the heart.   Thus
it is only by little and little, and when each fibre has been
as it were injected, that the powers of such fibres diminish
and  c£ase.   On the  contrary supposition,  their cessation
and diminution should be almost sudden.
  It may be  demanded  in what  manner the black blood
acts at. the extremities of the arteries,  upon the fibres of
the different organs.   Is it upon  the fibres themselves, or
upon  the nerves which  are  distributed  to them ?   I  am
rather inclined to suppose the latter to be the fact, and to
consider asphyxia  as an effect produced in general by  the
black blood upon the nerves,  which every where  accom-
pany  the arteries of a certain diameter :  for as we  shall
presently see, the debility which in such  case  the  heart
experiences,  is  only  a particular symptom  of  a  disease
in which the orgah.s  in  general are  the  seat of a like
debility. 
J24          PHYSIOLOGICAL RESEARCHES

   It might be demanded also in what way, that is to say,
by what manner of influence, the black blood acts  upon
the nerves or fibres.   Is it from  the principles which it
actually contains, or from the absence of those which are
proper to the red blood ?  Is  oxygen  the principle  of
irritability—are  hydrogen and carbon the reverse?
   These questions have been sufficiently  disputed.:—Let
us stop when we arrive at the limits of rigorous observa-
tion.  Now, I think, that we shall  establish an assertion
the most strictly conformable with such principle, in say-
ing generally and without determining the manner, that
the heart ceases to act, when the chemical functions of the
lungs are interrupted, because the black blood with which
its fleshy fibres are penetrated, is not of a nature to keep
up their action.
  From  this  manner of regarding  the  phenomena  of
asphyxia with relation to the. heart, it  is evident that
both the ventricles should  be equally affected by it, be-
cause their parietes must be equally injected with venous
blood.  Nevertheless, it  is  constantly  observable, that
the movement of  the red-blooded  heart is the Hirst to
stop  ; that the black-blooded  heart in every case the ulti-
mum moriens; but this phenomenon does not suppose a
more real, a more  decided debility in the one, than in the
other heart; for as Haller observes, the fact is  common
to every kind of death in the red-blooded  animal, and not
the case particularly in asphyxia.—Besides, were the red-
blooded heart the first to be absolutely affected,  as the
theory of Goodwyn supposes, the following would be the
appearances on opening the asphyxiated subject.—1st. A
distension of the corresponding auricle and ventricle,  by
the black blood which  they would  not be able  to  expel
into  the aorta.—2dly.  An equal fulness of the pulmo-
nary veins and lungs.—3dly. A  consequent  fulness and 
ON LIFE AND DEATH.
225
swelling of the pulmonary artery and the black-blooded
cavities.   In a word, the congestion of the blood  should
be the greatest in that of its reservoirs, whose action is
the first to cease.
  But this  is contrary to  observation—for  1st.  In  the
asphyxiated subject, the red-blooded  cavities and pulmo-
nary veinsj  contain but a very small quantity of blood in
proportion  to  that  which  distends the opposite heart.
2dly. The place  where the  blood  has  stopped, is found
to be principally in the lungs, in the lungs must we begin
to follow its accumulation into the venous system.   3dly.
The arteries are as full of blood as their  correspondent
ventricles, and consequently  it cannot be in the ventricle
more than elsewhere, that death has been begun.
  But what is the reason why the  black-blooded heart is
the last to beat ? because,  says Haller, it is the longest
excited ; because it contains  a greater quantity of  blood ;
because the blood is sent into it from the largest veins
of the system, and  regurgitates from  the lungs.  The
famous experiment is well  known by which in emptying
the black-blooded cavities, and  tying  the aorta so as to
retain the blood within the red-blooded cavities, the con-
tractions of the latter are prolonged so  much beyond the
contractions of the former.   But in this experiment it is
manifestly the black blood which accumulates in the aortic
auricle and ventricle, because the breast must be prelimi-
narily opened, and  therefore  the lungs collapse.
  Should a  more direct proof be required, immediately
before the experiment, let the trachea be  closed with a
syringe,  and the  air of the lungs be voided ; the experi-
ment will just as well succeed ;  besides,  the operator to
be sure of the colour of the  blood  in the aortic cavities,
has nothing more to do than  to open them, as soon as he
has finished his experiment.
              29 
226          PHYSIOLOGICAL RESEARCHES
  We shall conclude that the black blood is almost as
powerful a stimulus as the red blood to  the inner surface
of those cavities, which usually contain the latter only :
the reason why they are the  first to be arrested in their
action, is, because they do not receive so large a quantity
of blood as the others.
  Notwithstanding what I have said, I do not entirely
reject the  idea of the  red-blooded  ventricle being  not
excitable  by the black blood.  It may indeed  be less
excitable by this sort of blood, than  by  the other;  but I
believe that the preceding considerations will reduce this
difference of excitement to a mere trifle.
  The following, however, is an experiment where such
difference would  appear to be very  manifest.  If a stop
cock be adapted  to the trachea, and an artery opened, the
blood will blacken,  and  continue for some  time  to  be
thrown out with its ordinary force, but at last the jet will
gradually grow weaker.   If, after this,  the air be admit-
ted, the blood will almost immediately become red and
its jet be visibly augmented.  In this  case  the sudden
augmentation appears at first to depend upon the simple
contact of the red fluid with the sides of the aortic ven-
tricle, since it has not had the time to penetrate the  tissue
of the heart; but let things  be a little attentively  ex-
amined, and it will soon be seen that this impetuosity of
impulse, depends on the movements of inspiration and
expiration, to which the animal is obliged, on the admis-
sion  of  air into the lungs.   The  heart excited  at  its
exterior, and perhaps a little compressed by these move-
ments, is the occasion  of such phenomenon, and  expels
the blood with a force which is far beyond that which
results from its habitual contractions.
  What  I have here advanced is proved, by the manifest
diminution of the jet, as soon as once the lungs have  taken 
ON  LIFE  AND DEATH.
227
on their accustomed degree of action.  Besides, the influ-
ence  of a  series of full expirations may  be  manifested
without dividing the trachea.   Open the carotid and pre-
cipitate the respiration of the animal  by tormenting it
(for  pain will constantly have this effect)  and the jet of
blood will  be visibly increased.   The same augmentation
may  be artificially  produced,  by suddenly compressing
the parietes of the  thorax.   These experiments  succeed
best on animals already weakened by the loss  of a certain
quantity of blood.
  In  the ordinary  state of health however,  a  series of
strong expirations will not be found to  quicken the pulse.
Of this I cannot assign  the reason.
  From what we  have now said,  it  follows,  that  the
experiment, in wrhich, on the opening of the cock of the
syringe, the blood  is thrown out with augmented force,
is not so conclusive as might at first be imagined.  I con-
fess that it embarrassed me much for many days, I  hold
then my former conclusions to be good.
  In  the red and cold-blooded animals, the action of the
lungs has not so  immediate a connexion with  that of the
heart, as it has in the red and warm-blooded animals.
  I tied the lungs of  two  frogs at their basis, having
previously  exposed  them, by incisions made laterally into
the  breast,  the circulation however continued as usual for
a considerable time.  After this experiment, I have  seen
on opening the breast, the movements of the  heart  pre-
cipitated, a circumstance depending no doubt upon its
contact  with the air.
  I  shall finish  this chapter  by the examination of an
important question, and  inquire into the reason, why when
the chemical  functions of the lungs are stopped, the pul-
monary arteries,  the black-blooded cavities of the heart,
and in a word all the venous.system, are found so much 
22S
PHYSIOLOGICAL RESEARCHES
more full of blood, than the aortic system.   In such case
the circulation  appears at first to be interrupted in  the
lungs, and  then in the  other parts, according  to  their
proximity to the lungs.
  This  phenomenon must have been  observed by all
who have opened the asphyxiated  subject.   It has been
explained  by Haller and  others, from the  tortuosity of
the vessels ; but this opinion  I have sufficiently refuted.*
  But before I proceed  to assign  a more  real  cause,  I
Shall  observe,  that the lungs,  (when the blood is first
arrested, because  it finds in them the first obstacle  to its
progress,) are found in a singularly various state, accord-
ing to the kind  of death of which the individual has died.
In sudden, in instantaneous death, neither the lungs,  nor
the black-blooded  heart are very much  distended.
  I  have observed  this  fact, 1st.  In the bodies of two
persons  who had  hanged themselves  and were brought
into my  amphitheatre.  2dly. On two  subjects who  had
fallen into the  fire, and were  instantly suffocated.   3dly.
On dogs which  I have suddenly drowned.   4thly.  Upon
guinea-pigs, which I have killed in a vacuum, or  in differ-
ent gases, or otherwise.
  On  the  contrary,  arrest the phenomena of respiration
in a gradual manner ; drown  the animal by plunging him
in water, and taking him  out alternately, asphyxiate him

  * It is certain, whatever Bichat may say concerning it, that numerous
angles in the course of a blood-vessel, by increasing the friction, must
retard the  course of the fluid which  runs through its cavity.  We may
in fact believe that it is one of the  causes, which, in the flattening of
the lungs,  embarrass the circulation; this cause exerts its action princi-
pally upon the last ramifications of the pulmonary artery  which, by
their interlacing, form the bronchial cells ; another more powerful cause,
which acts equally  on the divisions of the vein and the artery is, as we
have said, the pressure made on the lungs by the flattening of the thorax.
and the elevation of the diaphragm. 
ON LIFE AND DEATH.
229
by placing him in a vessel of gas imperfectly closed, con-
tinue as long as possible such state of  pain and anguish,
and the lungs will be found extremely full of blood.
   Between the extreme  fulness, and the almost complete
emptiness of the pulmonary vessels, there is a variety of
degrees; now by the manner in  which we kill the animal,
we can deterrriine any one of these degrees at  will: It is
in this way that we  must explain  that  state of fulness in
the lungs of such  subjects,  as  are usually brought  into
our amphitheatres : in the greater  number of cases,  the
attacks of death are slow and gradual.
   But whatever be the state  of  the lungs in the asphyxi-
ated  subject, the venous system is full of black  blood,
especially about  the  heart.    In  this  respect,  there is
always a very  wide difference between  the veins and  the
arteries, and accordingly the blood must find in the lungs
the principal obstacle to its circulation  :  such obstacle, as
we have said,  does  not proceed from  the tortuosity, and
state  of collapse in the pulmonary  vessels;  its  causes are
relative, first to the blood, secondly, to the lungs, thirdly
to the heart.
   The principal cause depending  on the  blood, consists
in the great quantity of this  fluid,  which passes from  the
arteries into the veins.  In  fact we shall  soon see, that
the black blood when it circulates in the arteries,  is  not
capable of furnishing the materials of secretion, exhala-
tion,  or nutrition, or if it be  so, that it is not  a stimulus
to the organs which are the agents of these functions.*
  * See the article on the influence of the lungs on all the parts.  I am
compelled here to deduce  consequences from principles which 1 shall
prove hereafter; such is in fact the  connexion of questions which have
the circulation for their object,  that  the  solution of one draws as a
necessary consequence that of all the others. It is a circle in which it
is always necessary to suppose something, leaving it to be proved after-
wards. 
230
PHYSIOLOGICAL RESEARCHED
   It follows as a necessary consequence, that  the portion
 of fluid which is usually taken up from the arterial sys-
 tem by these different functions, flows on into the venous
 system, together with the portion which should naturally
 pass  thither; hence  there must  be contained a greater
 quantity than usual in the veins ; and therefore a greater
 difficulty be experienced in its passage through the lungs.
 Practitioners in opening  the bodies of asphyxiated per-
 sons, have  always  remarked  the  abundance  of  blood
 which is met with there.  The fact has been particularly
 remarked by Portal,  and  I have  always found  it. in my
 experiments.
   The causes of obstacle to the passage of the blood pro-
 ceeding from the lungs, are first the  non-excitement of
 this organ by arterial blood.  In asphyxia, the bronchial
 arteries are  penetrated by the black blood as  well as the
 rest.  Hence  its obscure  and dusky colour in this  case.
 This  colour and  its  successive  shades,  may be easily
 remarked in the collapsed lung, when the chest is open-
 ed ; but in asphyxia,  such blackness is principally owing
 to the colour of the  blood, contained  in the  pulmonary
 veins.
  The black blood  when circulating in the bronchial
vessels, produces upon the lungs the same effect which it
 does in the  heart, by penetrating the  coronary arteries ;
it weakens the different parts—impedes their action, and
the capillary secretions which should be made there, from
the tonic powers of the organ.
  The second cause of obstacle to the circulation, when
the chemical  functions of the lungs  are  interrupted, is
the non-excitement of the organ by vital air.  The first
effect of such  air  upon the mucous  surfaces  of the air-
cells, is to stimulate them, and  so to keep them up in a 
ON LIFE AND DEATH.
231
 aort of perpetual erethism.*  In  the  same way are  the
 powers of the stomach  brought into action  by the pre-
 sence of aliment there, and those of every reservoir of the
 body,  by the influx of their  accustomed fluids.  Again,
 such excitement of the mucous  surfaces by foreign sub-
 stances keeps up  their  tone.   The privation of such
 excitement, therefore, must  put a stop  to their capillary
 secretions, which depend upon their tonic powers.
   The different aeriform fluids which take the place of the
 atmospheric air in the different  sorts of asphyxia, appear
 to act very differently upon the tonic powers, or the insen-
 sible organic contractility of the lungs.  Some of these put
 a  sudden stop to the  circulation,  others not.  Compare
 the asphyxise  produced by nitrous  or sulphurated hydro-
 gen gas,  with those which  may be occasioned  by pure
 hydrogen, or carbonic acid  gas, and the difference will
 instantly  be  seen.   This difference indeed,  as  well as
 the various other phenomena observable  in  the various
 asphyxias, depends on  causes which we have not  men-
 tioned, but the affection of the air-cells, is evidently one
 of them.
   Lastly, the third cause of stagnation of the blood  in
 the venous vascular system,  is that debility, which  takes
 place in the ventricle  and auricle of this system,  when
 penetrated with venous blood : on  the influx of the  blood
 from the cava, they are consequently distended, and this
 is  the  case also with  the cava  itself,  for the very same
reason.   The causes which are now assigned, are sufficient
 to  shew  why  the  black-blooded system, is  gorged with

  *I cannot see what can have induced Bichat to admit this erethism
of  the lungs, the use of which cannot be imagined. It is quite enough
to suppose in the organs the exis-tence of  those  concealed properties,
when there is need of them to explain their functions. 
232           PHYSIOLOGICAL RESEARCHES
 fluids in asphyxiae.*  The  following considerations will
 shew why the red-blooded system contains a lesser quan-
 tity of fluid.
   1st.—The obstacle commences in the  lungs ;  therefore
 the aortic heart  must  receive a less quantity than  usual :
 hence, as we have  seen, proceeds  the quicker cessation  of
 the contractions of this ventricle.
   2dly.—The  natural  strength of  the  arteries, though
 enfeebled  by the influx of blood into  their parietes,  is
 much superior to  that  of the  veins, which besides are
 subject to the same  cause of debility.t  Accordingly these
 vessels and the aortic  ventricle, are  capable of surmount-
 ing the resistance of the capillary vessels  of the body in
 general, much more easily than the  veins and the venous
 ventricle, are of vanquishing the capillaries  of the lungs.
  * As the blood flows in the  veins in a continuous motion, the disten-
 sion of these vessels does  not  take place in the direct motion of the
blood, but in its retrograde  motion.  Every time the right auricle con-
tracts, a portion  of blood,  instead of passing into the ventricle of the
 same side, is forced back into the superior and inferior  venae cavae, and
 into the principal venous trunks which open into them.  By this reflux
 of the  blood, these  veins are dilated, and have  a pulsation which  is
easily seen  in'the jugular in very thin  people.   This pulsation has
 received the name of the venous pulse.  When it  is very evident, it
 may indicate an obstacle to the passage of the blood from  the auricle
 to the right ventricle.
  Another reflux of the blood  in the veins corresponds with the moment
 of expiration, and is perceptible even longer.  We shall soon have  to
speak of it, in speaking of the movements  of the brain.
  t The natural force of the arteries is not dependent on life, and con-
sequently cannot  be enfeebled by the  entrance of black blood.  This
force is nothing but elasticity, which indeed ceases to be  in action as soon
as death takes place, but which does not cease to  exist till the texture
itself is destroyed and disorganized.  As this property is very conspicu-
ous in the arteries, it is sufficient to drive the blood from their cavity  at
the instant of death, whilst it is too feeble in the veins to expel thie
fluid entirely.  Thus it is, that we find  blood in the veins only, after
 death. 
ON LIFE AND DEATH.
233
  3.dly.—In  the general capillary system, there  is only
one  cause of want of action, viz. the  presence of black
blood in  it ;  to  this in the lungs there is added another
cause,  the  want  of  that habitual excitement which  this
organ receives on the part of the atmospheric air:  accord-
ingly in  the lungs, there is a greater resistance offered  to
the influx of the blood, and with respect to the heart, a
less  capability of surmounting  such resistance.   In the
other parts,  the contrary  of all this  is  observed, a less
resistance to  the influx of the blood  from the arteries into
the veins on  the one hand, and  on the other a  greater
capability of overcoming such resistance.
  4thly.—In the  general capillary system, which is  con-
tinued on from  that of the arteries, if the circulation  be
embarrassed  at  first, in any  organ  in particular, it  may
still  continue to  go on in the other  organs, more or  less,
in which case the blood regurgitates by these others into
the veins.   On  the  contrary, as all the capillary  system,
which is the continuation of  the general venous  system,
is concentrated  in the lungs, the venous circulation must
be suppressed, whenever this organ loses its powers.
  The preceding considerations, if I  am  not mistaken,
explain  why the vascular systems  are so  unequally full
of blood after death, a circumstance, which is common to
almost every disease, as well as the asphyxia?.
  In the latter sort of death however, although the gene-
ral  capillary system presents a less degree of resistance
than is made by the capillary system  of the lungs, never-
theless such resistance arising from  the influx of the black
blood  into the  organs in general  is very manifest, and
produces two remarkable phenomena.
   The first is a greater quantity than  usual of black blood
in the arteries, and therefore  a greater difficulty of inject-
ing  these  vessels.   Such  blood is  seldom coagulated.
              30 
234          PHYSIOLOGICAL RESEARCHES
 Indeed in all  cases the venous blood is much less coagu-
 lable than arterial blood.  This  fact is  proved, 1st, By
 the  experiments  of  modern Chemists.   2dly,  By the
 comparison of the blood of varices with that of aneurisms.
 3dly,  By the inspection of that  which  usually stagnates
 after death in the veins of the neighbourhood of the heart.
   The second circumstance,  to which I  have referred, is
 the general livid colour of the greater number of the sur-
 faces, with the fulness of divers parts, such as the face, the
 tongue and lips.   These two  phenomena indicate a stagna-
 tion of the blood at the extremities of the arteries, in the
 same way as they denote the  same effect in  the pulmonary
 vessels; here there is  a much more evident repletion,
 because as I have said, the capillary system is there con-
 centrated within narrow limits.
   The  reflux of  the  blood  of  the veins towards the
 extremities is  the reason assigned by authors for the livid
 appearance of  asphyxiated persons.   There is little reality
 in this cause : in fact, this reflux, which is very sensible
 in the  trunks of the veins, diminishes continually towards
 their  ramifications, where it is  impeded  and  rendered
 impossible  by the  valves, besides which,  the following
 experiment is an evident proof, that we must attribute the
 lividity in  question,  to  the  impulse of  the  black blood
 from the aortic ventricle.
   1st.—Adapt a syringe with its  stop-cock to the divided
 trachea.  2dly, Open the abdomen  so as  to  distinguish
 the intestines and epiploon.  3dly, Shut the cock.  At the
 end of two or  three minutes,  the red tint which animates
 the peritoneum, and  which  is borrowed by  this mem-
 brane from the vessels, which creep underneath it, will be
changed  into  a dull brown colour.   This colour may be
 made to  disappear and  re-appear at  will, by opening or
shutting the syringe. 
ON LIFE AND DEATH.              235
  Here we cannot, as if the experiment were made upon
other parts, suspect that a reflux is propogated from  the
right ventricle  towards the  venous  extremities,  since
the mesenteric veins, together with the other branches of
the vena portse,  form a  system apart, independent of the
great black-blooded system, and having no  communica-
tion with the cavities of the heart which correspond with
this system.
  But I shall  touch again upon this subject.   The above
experiment is amply sufficient  to prove, that the lividity
of the surfaces of  the body  is owing to arterial impulse.
  At present we  are in a condition to explain how the
lungs are  more  or less  gorged with blood, more or  less
livid, and how the livid  spots upon  the different parts
of  the body  are  more or  less  marked  accordingly as
the asphyxia has been  more or less prolonged : for  it is
evident,  that  if  before  death, the  black blood  have gone
round the two systems  ten or twelve times,  it will inject
the extremities  much more than if it had made such cir-
culation  only two or three times ; at  each revolution, a
greater or less  quantity will be left in  the extremities,
for want of  action in the capillary vessels.
  In finishing this chapter I shall take occasion to observe,
that the spleen is the only organ of the economy suscepti-
ble like  the  lungs of  assuming a  very  great variety of
volume.   Scarcely is it ever found in  the same state.  It
has been falsely  supposed that there is a relation between
the plenitude  or vacuity of the stomach, and  the inequali-
ties of the spleen; but  this is not the  case, as I have  said
elsewhere.  Such inequalities during the life of the body
do  not exist, and supervene only at the instant of death.
   It appears  to me, that they depend especially upon the
state of the liver, the capillary vessels of which, are the
continuations of all the branches of the  vena portae as 
236
PHYSIOLOGICAL RESEARCHES
the capillaries of the lungs  are those of the great venous
system.   Thus, when  the  hepatic  capillaries  from any
cause whatever are enfeebled, the spleen  must  swell and
be filled with the blood, which cannot traverse the liver.*
In  such  case,  if I may so express  myself,  there  is  an
isolated  asphyxia of  the abdominal  vascular  apparatus.
The liver being to the  spleen, what the lungs are to the
black-blooded  cavities in common asphyxia.   The  resis-
tance is in the former, the stagnation  in  the latter.   But
this matter  may  be  better understood  hereafter.   Ex-
riments  upon   animals  killed  in different ways,  would
throw much light upon  it, and these I purpose  undertak-
ing.  By these  means we   may rigorously establish  the

  * The state of the spleen in the  dead body may become in some
measure  an index  of the state of the  circulation during the last moments
of life.   The swelling of it shows  almost always the embarrassment of
the circulation; and not only  in an insulated  system,  such as that of the
vena porta, as Bichat considers it, but in the whole pulmonary system.
  When any cause impedes  the  circulation in  the capillaries of the
lungs, it  necessarily produces a stagnation of the  blood in the divisions
of the pulmonary  artery, and by degrees the disturbance is felt even in
the two venae cavae, but especially in the inferior in which  the blood
rises against its gravity.  The  blood  accumulates in  the  principal
branches ;  the veins of the liver and kidneys swell more or less ; as to
these organs themselves, the firmness  of their texture  hardly allows
them to be distended, so they do not increase sensibly in size, or if this
increase  takes place, it is slow. It is not the same with the spleen ; the
looseness of its texture will admit a great quantity of liquid, and its
size can thus be doubled or trebled  in a very short  time.   It becomes
then a kind of reservoir, in which  is accumulated the blood which
cannot pass through the lungs.
  It may be objected to  what we  have just said,  that oftentimes in
phthisis the greatest portion  of the lungs  has  become  incapable of
allowing the blood to pass, and that yet after death, the spleen is found
in a natural state.   But it should be  recollected, that phthisical patients
have, during the latter part of their  lives, but very little blood, so  that
each portion sent by the right ventricle always finds a sufficient channel
for it in the lungs. 
ON LIFE AND  DEATH.
237
analogy existing between the stagnation of the blood  in
the different branches of the vena portae, and  that which
is observed in the general venous system, in consequence
of various kinds of death.   With respect to the spleen and
its system  of  veins, in ordinary  asphyxia, I  have never
remarked in it any  peculiarity.
                    CHAPTER VII.

OF THE INFLUENCE OF THE  DEATH OF THE  LUNGS OVER
                 THAT OF THE  BRAIN.

  We have just seen, that  in  asphyxia, the  movements
of the heart are  paralyzed, because  its  fleshy fibres are
penetrated  with venous blood.   This fact should indicate
the same  to be the case with  reference to  the  action of the
brain.  It is indubitably proved by experiment.
  Whatever be  the  manner  in  which  the pulmonary
functions are interrupted,  it is  always the interruption of
the chemical changes, which troubles the functions of the
brain.*   What  I  have said  upon  this point with  respect
  * In a preceding  article, Bichat maintains that  the entrance of the
arterial blood contributes to support the action of the brain, principally
by the jar which it communicates to this organ.  It is astonishing, after
this, that he should  attribute the suspension of the  cerebral functions to
the interruption of the chemical phenomena of respiration rather than
to that of the mechanical phenomena.  He  could not however be
ignorant, that it is to  the last that  must be referred the greatest of the
two motions with which the brain is constantly agitated.
  These motions of the brain in relation with those of respiration have
been for a long time observed.   Schitling has described them in a
memoir inserted in the first volume of the Memoirs of Learned Foreigners.
He has shown that the brain rises in expiration, and flattens in inspira- 
238
PHYSIOLOGICAL RESEARCHES
 to the heart, is exactly applicable to the cerebral mass :  I
 shall  not repeat it.   It remains to shew by experiment,

 tion.  Haller, Lamure and Lorry have since him investigated this motion,
 and they have given an  explanation of  it,  which is defective only
 because they have been ignorant of the  influence of respiration on the
 acceleration of the  course  of the  blood  in  the arteries through the
 medium  of the capillary vessel*.
   At the time of a strong expiration, all  the  pectoral and abdominal
 organs are compressed, and the arterial blood  is forced more especially
 into the  branches  of the  ascending aorta.  This  blood goes then in
greater abundance towards the head, and has  a tendency to pass  more
quickly in the veins which  carry it towards  the heart; which would
take place immediately if the  veins  were  free.   But the  pressure
made on the pectoral organs has also made the venous  blood flow back
in the vessels which contain  it.   Now, this  blood  has just met that
which comes  from the arteries ; the vessel is distended, and the course
of the fluid is arrested in the veins ; from that  the brain swells and rises
up; but as soon as expiration has ceased, the dilatation which takes  place
in the chest attracts, in some measure, the blood of the  superior  vense
cavae;  the veins which  enter it are soon emptied and the brain flattens
down.
   In reflecting on  the mechanism by which this movement of the  brain
is effected by the influence of respiration, we  cannot perceive why the
phenomenon  should be  limited   to  the organ contained within the
cranium, and  especially why the spinal marrow should not equally
partake of it.  The  continuity of this  organ  with  the cerebrum and
cerebellum, its situation iu a cavity which  it does not  entirely fill, the
numerous arteries  which it receives from the  intercostal and vertebral
arteries, the number and size of its veins  destitute of valves are so many
circumstances which should favour the  accumulation  of the  blood
at the time of expiration, and consequently produce its swelling.  For
the purpose of seeing  if  my conjectures  were well founded, I  have
made some experiments ; I laid bare in a young rabbit the spinal marrow
at about  the eighth or  ninth dorsal verterbra, I saw it perfectly whole
and surrounded by its coverings.   At first 1 perceived  no motion, but
soon the  animal being  much incommoded by the position in which I
kept him, made a deep inspiration, and then I  saw distinctly the spinal
marrow flatten, and a small vacuum between  the dura mater and the
osseous parietes of the  vertebral  canal.  In the following  expiration. 
ON LIFE AND DEATH.
239
and the observation of diseases, that when the chemical
functions of the  lungs  are put a stop to, it is the  black
blood  which interrupts  the action of the brain and that of
the nervous system.   In the first place let us examine our
experiments.
   I first began by transfusing into the brain of an animal,
the arterial blood of another, that this essay might serve
as  a point  of comparison  for others.   Open  one of the
carotids of a  dog ;  tie  the extremity tovvards the brain,
and fasten  a tube to that which is  next  the heart;  then
open the carotid  of  another dog, tie the extremity of the
vessel next the heart, and  fix the  other  end of  the  tube
into that which is next  the brain ; then  let the assistant,
who  meanwhile  should have  had  his  fingers upon the
artery of the  first dog  underneath the  tube,  remove his
compression, and the carotid of the  second dog will  be
seen beating under the impulse of the blood injected  from
the heart of the  first.   This operation fatigues but  little
the animal  which receives  the  blood, particularly if one

the spinal marrow resumed its original size.  I was unable to see any
thing more in this animal.
  I laid bare in a dog of middle  size, the spinal  marrow, a little  above
the lumbar region;  I could  not mistake there a  very evident motion,
in  relation with respiration : a flattening during inspiration, and a swel-
ling during expiration. The  phenomenon was so marked, that the air
entered the vertebral canal with a noise, whilst the animal  inspired, and
was forced out when the animal expelled the air from his lungs.
  For the purpose of satisfying myself that this motion took place  in tht
spinal marrow and not in the dura-mater, I cut this membrane in the
whole extent of the  opening made in  the vertebral canal-, and  I wa9
able easily to convince myself that the motion was from  the swelling
of  the «pinal marrow. I am  not  howfver certain that there is  not a
slight rising of the organ from the dilatation of the large  veins in the
anterior part of the vertebral canal, but this dilatation cannot be con-
siderable, on account of the fibrous layer which covers the posterior face
ef  these veins. 
240
PHYSIOLOGICAL RESEARCHES
 of the veins be previously opened, to prevent too great a
 fulness*of the vessels.  It will live very well afterwards.
 This experiment has been often repeated, and  always
 with the same results.
   After this experiment, I opened the carotid, and  the
jugular vein of another dog, and after tying the extremity
 of the carotid next  the  heart, received the blood of the
jugular into a  warm syringe,  and injected  it into the
 brain.  The creature appeared immediately to be agitated,
 breathed quickly, and seemed to be in a state of suffoca-
 tion, similar to that of asphyxia.  Its animal life became
 entirely extinct; the heart, however, continued  to beat,
 and tjie circulation to go on for  half an  hour afterwards ;
 at the end of which time the organic life was terminated
 also.
   This  dog was of a middle size, and about six ounces of
blood were injected with a  gentle impulse, for fear of that
being attributed to the shock,  which ought to have been
the result of the nature and composition of the  fluid.  I
repeated this experiment upon three dogs the same day,
and afterwards  at  different  times upon others;  the result
was invariable, not only as  to the asphyxia  of the animal,
but even as to the concominant appearances.
   It might be thought that out of its vessels, and exposed
to the contact of the air, the blood might  imbibe a per-
nicious principle, or be deprived of that which is requisite
for the  maintenance  of life.   It  might be imagined, that
to this cause was owing the  sudden death of the dog, on
the injection of the brain with venous blood.   To shew
that this was not the case, I made a small opening in the
jugular of a dog, to which I adapted a moderately warm
syringe, and pumped the  blood immediately  from the
vein.—It  was afterwards thrown into  the carotid: the
symptoms were the same as the preceding, but less mark- 
ON LIFE AND DEATH.
241
ed, and the death of the creature induced more slowly.__
It is probable, then, that the air when in contact with the
living  blood without its vessels  may alter it a little, but
the essential cause of death is still the same.
   Hence it appears that the black blood  either is not an
excitant capable of keeping up the cerebral action, or that
it acts in  a deleterious manner, upon  the brain.  The
injection by the  carotid of various other substances will
produce analogous effects.
   I have killed  animals in this way with ink, oil, wine,
and water coloured with indigo.   The greater number of
the excrementitious  fluids, such as urine, bile, the mucus
of catarrhs, occasion death also by their simple presence
on the brain.   The serosity of the blood is fatal, but not
as quickly  so.   Now it is  certainly upon the substance of
the brain4 and not upon the internal surface of the arteries,
that these  different  substances  exert their  influence.   I
have  injected them  all  into  the crural  artery.   In this
way they are none of them  mortal,  but qccasion  always
a torpor, amounting even to paralysis at  times.*

  * Active substances introduced into the veins can act on the  organs
in many ways at once.  They have at first their peculiar^action which is
nearly uniform, whatever may be the mode of administration ;  but they
produce also  other effects resulting from their physical properties, and
these last may vary according to the form in which they are introduced.
  The substance? introduced into the circulation have necessarily to
pass through  a double system  of capillary vessels, and must  conse-
quently be very greatly subdivided.  Hence we see that a viscid fluid
would be unable to enter the smallest vessels, and that by remaining in
those which can admit it, it will prevent the passage of the blood, and
occasion a congestion either of the lungs or some  other organ, accord-
ing as it has  been injected into  a vein or an artery.  A substance like
quicksilver, which without being viscid, exhibits great cohesion among
its particles,  will produce precisely the same effects.  The  globules
wifl never divide below a certain size.  The  air itself, mixed in  a fluid
such as the blood, will form bubbles which will divide with more diffi=
               31 
242            PHYSIOLOGICAL RESEARCHES

   The black blood is doubtless fatal to the brain, the brain
becoming at once a tonic from its presence.   In wThat way

culty as they become smaller, and which can finally stop in the entrance
of the capillaries, so as to prevent a free  passage  of blood in a part of
these vessels.  Boerhaave  thought,that it was always thus, by opposing
a mechanical obstacle  to the capillary circulation of the lungs, 'that air
injected into the veins produced the death of th« animal.
  In an experiment in  which I proposed to myself  to change the.nature
of the blood by a  foreign fluid, I injected  into the  jugular vein of a
dog, an ounce  of Olive oil, thinking that this substance would circulate
without inconvenience with the blood ;  but it was not  so, and the
animal died in  a few minutes after the injection.
  In examining the organs after death,] saw that the oil had closed the
last ramifications of the pulmonary artery, and that it had  also stopped
the circulation and respiration, by preventing the  passage of  the blood
to the left  side of the heart,  by the pulmonary  veins.   An injection
made with a thick solution of  gum  tragacanth produced  precisely the
same  phenomena as the oil.
  An inert, impalpable powder, suspended  in water, immediately pro-
duces death, if injected  into the jugular vein, because it  shuts up the
last divisions of the pulmonary artery.
  If the injected substances are not divided at first in the blood, so as
to spread uniformly into the different branches, death does  not take
place so quickly, because a part of  the sanguineous canals remains
free for the circulation.  This is the case when we  inject quicksilver
or air in so  small a quantity as not to produce  instantaneous death.
The congestion,  in this last case, is  often  alone sufficient to produce it
after a certain  time ; in the other case, there is added to the obstruction
a real pneumonia caused by the presence of quicksilver in the obliterat-
ed vessels.  We shall now relate four experiments of M. Gaspard, which
will show the effects of the stagnation of this fluid in different organs.
  " First  Experiment.  I introduced into the jugular vein of a small
dog, four days  old, thirty six grains of quicksilver purified through goat's
skin.   Soon after he refused to suck, lost his vivacity, motility and heat,
had dyspnoea  and fever, and  died  at the end of twenty four  hours,
having been all the time much colder to the touch  than the other pups
with whom he  was.  On opening the thorax, the lungs were found mTuch
inflamed, almost hepatized, heavy, puckered up and full of mercury."
  " Second  Experiment.   I injected into the left carotid artery of a
sheep, very near the brain,  half an ounce of mercury with  water; I 
ON LIFE AND DEATH.                 243
does it act ?  I do not pretend to determine the manner;
for this were only to  begin a series  of conjectures.

then tied with a double ligature the open vessel.  The animal immedi-
ately manifested  pain,  and was for an instant immoveable,, the head
inclined, with stupor and a prominence of the  eyes, which were extra-
ordinarily open; then bending on  the  fore legs, twisting of the head
and  neck  on the ri^lit  shoulder, with a kihd of stiffness or convulsive
elasticity, which was always present til) death, and returned, as by
the  effect of a  sprin;;,  when I  straightened  the  neck.  Two  hours
after, standing impossible, state of drowsiness, some convulsive motions
of the limbs, the left eye swelled, red and inflamed.   The next day,
the same state, almost total annihilation of  the animal or external life,
copious excretion of mucus by the left nostril, the eye  still very large
and  inflamed.   The third day, the  same state ;  death took place fifty
hours after the injection.  On examination of the body it was  found
that the left eye was in a state of suppuration  and  contained mercury;
the  thyroid, pharyngeal auricular,  lingual, labial, nasal and cerebral
arteries of the left side, were admirably injected with this metal  which
run  out  under the  instrument; but  their capillary terminations con-
tained none  of  it,  and we could  see to  what ramification, to what
sized caliber it had  penetrated, and the point where it was unable to
pass; the left nasal cavities exhibited a very pretty reticulated appear-
ance, brilliant and  silvery.  Moreover  all  the organs of this side were
red, inflamed  and swelled  by the  presence  of  the foreign body, and
it was curious to see the half  of the thyroid gland,  the tongue, the
cheeks  and the lips thus  red and  inflamed to the median line, whilst
the  other half was sound  and pale ; the left brain was slightly inflamed
and especially the plexus  choroides.  Besides, I  was  unable  to dis-
cover a globule  of quicksilver in any of the other organs."
   " Third Experiment.  I forced with a pewter syringe into the crural
artery of a large  dog, a drachm and a half of quicksilver mixed with
common water.   The animal, immediately after the double ligature, did
not  manifest any sign of  paiit, and  walked, bearing less on that limb,
 which was  very sensibly cold,  though nof paralyzed.   But about an
 hour after,  he refused  food, manifested  by piercing cries  acute pain,
 constant agitation, frequent change of place,  and  a very evident state
 of suffering ; the limb soon ofter grew warm, became hot to the touch,
 with an obscure pulse under the tendo Achillis.  This state of fever and
 pain continued the whole day and night.  The next day, the limb was
 swollen and exhibited  a phlegmonous icdema  preserving the  impres- 
 244             PHYSIOLOGICAL RESEARCHES

    By this  time we  are authorised to  conclude-, that  in
 asphyxia?, the  circulation which continues for some time

 sion of the finger;  the  plantive cries were continual.  On the  third
 day his  condition was still worse,  and I then killed  him  from  com-
 passion sixty hours  after the injection.   I had carefully noticed the
 matter of the excretions, without discovering  a particle of  quicksilver
 in them.   On examination of the body, I  could not discover it in any
 organ, except the limb subjected to the experiment, which was swollen,
 inflamed  and oedematous  in  all its textures;  ive  observed abscesses
 in it of different sizes, containing quicksilver, pus, sanies and much gas,
 coming from the  incipient gangrene of the parts; Ihe metal  usually
 occupied  the centre of all the abscesses ; the mercurial globules flowed
,out when I cut the skin, the cellular texture, the muscles and especially
 the  small  arteries, which were  admirably injected by it;  gelatinous
 exudations occupied the interstices  of  the muscles.'"
  "Fourth Experiment.  I injected a drachm of quicksilver, that had
 been passed through goat's skin, info  the mesentric vein of a dog of
 middle size.  The animal exhibited several severe symptoms which I
 shall not  mention, because they probably  depended on the  opening of
 the  abdomen  and the  inflammation  that  resulted  from it;  perceiving
 that they  would  become fatal,  I killed  him by  another experiment,
 fifty two hours after the  first.  On  opening the body, I found  all the
 mercury  in the liver ; each globule was the centre of a small collection
 of pus, of  which it was the cause;  but the liver was but slightly dis-
 eased, but little  inflamed, and only blacker and more gorged  with blood
 than usual.  The stomach contained an unusual quantity of very green
 bile ; I could not discover any quicksilver in the other organs."
  We  see  from  all these  different facts, that it is  necessary for every
 thing that enters the circulation to arrive at it by very narrow channels,
 and  after having been, as  it were, sifted by the agents of absorption ;
 this is one  use of the absorbent organs that has not as yet been noticed.
 These  facts also throw light  on  the  properties  of substances injected
 into the veins of animals, after having been dissolved in oil.  We can
 believe that when these  oily solutions are carried  into the intestinal
 canal, they are not absorbed till after they have  been gradually changed
 into a kind of emulsion, andwe know that in this form fatty substances
 may be introduced with impunity into the circulation.   We can  in fact
 inject into the veins a large quantity of milk, and the portion of butter
 which  is suspended  in it,  will  not produce  the effects which would
 necessarily result  from it, if we  injected this substance pure and  only
 rendered liquid by heat. 
ON LIFE AN© DEATH.              245
 after the interruption  of the  chemical functions of the
 lungs,  interrupts  the cerebral  functions,  from its being
 composed of black  blood  only.  The  fact is proved  in
 another manner, for the movements of the brain continue
 to be made as  usual.
   If the cerebral  mass be exposed,  and  the creature
 asphyxiated, the animal life will be extinguished, but the
 motion of the brain will be apparent still.  Since then the
 latter cause of life subsists, the cause of death must be  in
 the nature of the  fluid, by which  the organ is penetrated.
   Nevertheless, if any affection of the brain coincide with
 asphyxia, the  death which is  occasioned by the latter,
 will  be quicker than is usually the case.   Strike a dog a
 violent blow upon the head, and then if he be deprived of
 air,  he  will die on the instant.  In asphyxiating another
 animal  already  in  a state of stupor, from  compression of
 the brain, I observed that the vital functions were inter-
 rupted  somewhat sooner, than when the brain  is untouched
 during  that operation ;  but  the  consequences hitherto
.deduced, may  be  supported by  other experiments.
   If in  asphyxia the black blood suspend the  action of the
 cerebral  mass, it  is  evident, that the  black  blood taken
 from the arteries  of an  animal dying of asphyxia, and
 injected into the  brain of another, will be  the cause of
 death.
   The  experiment will  be found to succeed—cut the
 trachea, of a dog, and tie it up hermetically ; then in the
 course  of two  or  three  minutes,  open the  carotid and
 receive  into a  syringe  the  blood,  which flows from the
 vessels  ; inject it  into the brain of another animal, and it
 will die.
   The  following experiment is very similar, but offers a
 somewhat different result.   1st. Adapt a tube with a stop-
 cock to the trachea of a dog, and a tube of silver to the 
246          PHYSIOLOGICAL RESEARCHES

carotid, next the head, after dividing this vessel, and tie
up the extremity towards the heart.  2dly. Fix the other
end of the tube to the divided carotid of another dog next
the heart, and tie. the  extremity  of the  vessel tow;!ids
the head.   3dly. Shut the cock of the tube in the trachea,
and the black  blood of the one dog in a short, time, will
be injected into the brain of the other.
  The appearances above described  will shortly  after-
wards succeed, but  not so soon as  in the former experi-
ment, and if the transfusion be stopped, the animal which
has been asphyxiated  in this  way,  may  recover and live.
In  the  preceding experiment he  will  always die.   It
appears then that some  extraneous  pernicious principle is
imbibed  by the venous blood, when in contact with  the
air.  Observe  that for the latter experiment the dog from
which  the  brain of the other is to be  injected, must be
stronger and more vigorous than the other.   The reasons
are evident.
  I  was desirous of trying whether  the venous  blood
would  not  be  capable of keeping  up the cerebral action,
if reddened artificially.  For this  purpose I opened  the
jugular and the  carotid of a dog, and received  the  blood
of the vein in  a vessel filled with ox}^gen; it immediately
became of a vivid purple, but on its  injection  into  the
brain, the animal was very suddenly killed.   I was much
surprised at this result,  but ceased  to be so on remarking
that a great quantity of air was  mixed  with  the fluid,
and  that it arrived  upon  the  brain, in a state of  foam:
now we  know that a very small number of bubbles are
sufficient to kill an  animal,  whether they be introduced
on the side  of the brain, or on  that of  the heart.
,   From this reflection, I was induced to repeat my expe-
riments upon  the'injection of black blood, suspecting as
I did that some small quantity of air might in these cases 
ON LIFE AND DEATH.
247
have been contained in  the extremity of my syringe.   I
soon however recollected  that if this cause were  real, it
should produce the same effect in every instance whatever
were  the fluid employed, now when water is injected
there is nothing of the  kind observable.
  We may be thus assured that the black  blood is either
incapable of keeping up the action of the brain,  or that
it acts in a deleterious manner upon that organ, from the
very nature of the principles,  which it contains.   From
such datum it should appear that the life of the asphyxi-
ated person might be  restored, by pushing on into the
brain a sufficient quantity  of arterial blood,  but here  we
must make a distinction of two periods in  asphyxia:  1st.
That in which the cerebral functions are only suspended:
2dly. That  in which the circulation and the  movements
of the breast are stopped (for this disease is ever  charac-
terised  by the  sudden  loss of all  animal  life, and con-
secutively by that of the organic life.)  Now, as  long as
the first period  of asphyxia continues, I  have observed
that, by the transfusion of red  blood into the brain, from
the heart of another animal, the movement of the crea-
ture which is dying will be restored by degrees, and the
cerebral functions resume  in part their activity ;  but this
is only a temporary thing, and the  animal  will fall again
into its previous dying state, if the asphyxiating cause be
continued
  On  the other hand, if during the  first period, to which
we  have alluded, the air be readmitted, into  the trachea,
the lungs will be reanimated, the blood be coloured, and
the creature  be  revived without the assistance  of any
transfusion ; and such  transfusion  again is of no avail,
after the second  period of asphyxia, so that this  experi-
ment offers only a proof of what we already know ; with
respect to the difference of the influence  of  arterial and 
348
PHYSIOLOGICAL RESEARCHES
venous  blood  upon the brain, and not a remedy in  case
of asphyxia.
  Again,  whenever I  have injected  venous blood  into
the brain,  by  the  help of a syringe,  I  have universally
found that  such proceeding is fatal.  Though the cause of
asphyxia be removed, and arterial blood injected, either
with the syringe, or immediately from  the heart of another
animal,  it is of little effect, and frequently of none what-
ever.  And in general  asphyxia when  produced  by blood,
which has been taken from the venons system  itself and
pushed  into the brain  is  much  more certain and more
decided, than that which is occasioned by ligature of the
trachea,  or the introduction of  different  gases into the
lungs.
  After having established by different experiments, how
fatal the  influence of the  black blood is upon the brain,
which receives it from the arteries whenever the chemical
functions of the lungs-are suspended,  it will not be amiss
or out of  place to  shew, that  the  phenomena of the
asphyxia,   which  are  observed  in the  human subject,
accord with the experiments of which I have given the
detail.
  1st. It is generally known that every kind of asphyxia
affects the brain in  the first instance ; that the functions
of this organ  are  the  first to be annihilated ;  that the
animal life, and particularly the sensations cease; that all
our relations with exterior objects are instantly suspend-
ed,  and  that the organic functions are only consecutively
interrupted.  Whatever  be the mode  of  asphyxia, by
submersion, strangulation,  gases, or a vacuum, the same
phenomena occur at all times.
  2dly.  It is known that  the greater number  of those
who have escaped suffocation, have been  sensible only of
a general stupor, the seat of which has been evidently in 
ON  LIFE AND DEATH.
249
the brain.   It is known also, that death is almost  always
certain in these cases, while the pulse and the heart have
ceased to be felt.
  3dly.  It is affirmed by almost all such persons as have
survived  this  accident, especially  when caused  by the
vapour  of charcoal,  that the  first thing of which they
were sensible, was more or less pain in the head, an effect
in all probability  occasioned by the  first  influx  of the
black blood into the brain.   This fact has been noted by
the  greater number of authors, who  have  written  on
asphyxia.
  4thly. The  vulgar expression that "charcoal  flies to
the head "  is surely a proof  that the  brain, and not the
heart, is the first  affected  in the asphyxia occasioned by
this  deleterious  substance.    The  unprejudiced  vulgar,
oftentimes observe more correctly than we do, who fre-
quently sec only what  we wish  to see.*
  5thly. There are many examples of persons,  who after
escaping the pernicious effects of the vapour of charcoal,
have been subject afterwards to paralytic  affections, and
loss of memory.   Such changes have evidently their seat
in the brain.   Convulsion  also  is frequently the effect of
the impression of mephitic  vapour :  head-ache is  a com-
mon symptom, and for the most part  remains after the
others have disappeared.   In every book  of cases may
be seen examples  of these affections.
  In cold-blooded animals, and in reptiles especially, this
influence of the black blood on  the brain, though real, is
  * Is it true that  common people observe without prejudice ? Have
they not, on the  contrary, on several  physiological  and  pathological
phenomena deeply rooted prejudices?  It  is besides a very singular
idea to wish to judge  by the name which they give to an affection, of
the organ primarily affected.  If we always  reasoned in this way the
expression of sick at heart which is given to  nausea, would  assign to
vomiting a wholly different nature from what would be correct.
              32 
250
PHYSIOLOGICAL RESEARCHES
much less  apparent.  Make an incision  into  both sides
of the breast of a frog,  then  tie the. lungs at  their root,
and  the  animal will live  notwithstanding for  a  consid-
erable time.  Cut away  the lungs entirely, and the same
phenomenon will  be remarked.   In  fish, the relation
between  the lungs  and the  brain, is  somewhat  more
direct, for  by  the  organization  of the  branchiae, they
differ essentially from reptiles.   I  have  taken away  the
cartilaginous plate which covers the gills  of the carp,
the motion  of the gills  however continued to be made as
before, and the animal lived vvithout any apparent injury
done to its  functions.   I afterwards put a ligature  about
the cartilaginous rings which sustain the  branchiae, so as
to hinder all motion in the pulmonary apparatus.  The
effect was, that the animal languished,  his fins  dropt,
his muscular movements  soon grew weak, then ceased
entirely, and the creature  in the course of a quarter of an
hour was dead.  The same phenomena vvith  some little
variety, were observable in a carp from which  I cut away
the branchiae.
   After all however, the particular nature of  those rela-
tions, which unite  the  heart, the lungs,  and   the brain,
both in the red and  cold-blooded  animals, is well worthy
the farther investigation  of physiologists.   The latter sort
of animals,  can neither be  subject  to  syncope or apo-
plexy, or at least the character of these diseases must be
very much  modified in them.  They are with much more
difficulty asphyxiated.   We  shall  now  return  to  those
species which bear a nearer resemblance to man.  •
   From  the influence of the black  blood over the heart,
the brain,  and  the rest of the organs, it was my opin-
ion, that persons affected with varicose aneurisms, would
perish less quickly from  asphyxia  then others;  because
the red blood passes into the veins, and traverses the lungs 
                  ON LIFE AND DEATH.            j251

 without requiring alteration.   Accordingly, it should  be
 capable of keeping up the cerebral action.
   To  be assured if this  suspicion were  well  founded, I
 made  a communication  between the carotid  artery and
 jugular vein of a dog, by means of a curved  tube.  The
 pulsation of the artery was  thus  communicated  to the
 vein.   I afterwards  asphyxiated the animal by stopping
 the trachea,  but  the phenomena of death were little dif-
 ferent from those of common  asphyxia.
   We may conclude  with certainty, from the  various
 considerations and experiments presented in  the  present
 chapter.
   1st. That when  the chemical  phenomena of the lungs
 are interrupted, the  black blood acts upon the brain, as if
 does  upon  the  heart, by penetrating the  tissue  of that
 organ, and depriving it of the  excitement, which is neces-
 sary to its action.
   2dly.  That its  influence is  much more rapid upon the
 first, than on the second of these organs.
   3dly.  That it is the inequality of such influence, which
 occasions the difference in the cessation of the two  lives
 in the  case of asphyxia.   The animal life is always anni-
 hilated before the organic life.
   We may conceive from what has been said  in this and
 the preceding chapter, how unfounded are the suspicions
 of those who have supposed that the brain, after the sepa-
ration  of the head from the body by the guillotine, might
live awhile and have sensation.  The action of this organ
is  immediately connected with its double  excitements.—
 1st, By motion;  2dly,  By the nature of the blood which
it receives.  Now, when  the interruption of such  excite-
ment is sudden, the interruption of every kind of  feeling
must also be sudden. 
252          PHYSIOLOGICAL RESEARCHES

  When the chemical functions of the lungs are suspend-
ed, the disturbance induced in the functions of the brain,
has indeed a very considerable influence  on the death of
the other  organs ;  nevertheless,  such disturbance  is the
beginning of death only in the animal life, and even then
is connected with  other causes.   The organic life ceases
from the sole presence of the black  blood among the dif-
ferent organs.  The death of the brain is  only an isolated
and partial phenomenon of asphyxia, which  does not take
place in any particular organ, but in all alike.  We shall
explain this  assertion in  the following chapter.
                  CHAPTER  VIII.

OP THE INFLUENCE OF THE DEATH OF THE LUNGS OVER
          THAT OF THE  ORGANS IN GENERAL.

  I have just shewn in what way the interruption of the
chemical phenomena which take place in the lungs, anni-
hilates the functions of the heart and brain.   It remains
me to shew, that the other organs of the  body are as much
affected by such cessation ; so  that asphyxia, as I have
said, is a general disease, and not an  affection of any one
organ in particular.
  But before I proceed to analyze the effects of asphyxia
upon the organs in general, and consequently the mode of
action  of the black blood upon them,  it  may be of use to
explain the phenomena of the  production of this kind of
blood,  at the instant when the functious of the lungs  are
suspended.  This  paragraph will possess, perhaps, some
interest; it might have belonged indifferently to either of
the preceding chapters. 
                ON LIFE AND DEATH.             253


1.  Exposition of the phenomena of the production of
  black blood, when the chemical functions of the lungs
  are suspended.

  It is known  in general, that  the  blood  is coloured in
traversing the lungs, that from black it becomes red ;  but
this very interesting fact, has not been hitherto the object
of any precise or rigorous experiment.  The lungs of the
frog,  of which the air vessels are large, and  the mem-
branes thin  and transparent, would serve very well for
the purpose  of  observing the process of  the phenomenon
in  question,  but for the slowness of respiration in these
animals, the difference of organization in their lungs, and
the too small quantity of blood by which they are  travers-
ed.  On such account there can be little analogy between
them and the more perfect  animals, and then  again our
experiments upon  these  little amphibia?, are all of them
rendered incomplete, by the tenuity of their pulmonary
vessels, and the impossibility of observing the correspond-
ence of the change of velocity in the circulation, with the
colour of their blood.
  The phenomena of the respiration of man, and those of
the functions which are dependent on it,  can be illustrated
only by experiments made upon animals  with a double
ventricle, with  a complete pulmonary apparatus, possessed
of a temperature superior to that of  the atmosphere, and
the two separate  systems of. venous and arterial  blood ;
but on the other hand, in the mammalia resembling man,
their  respiratory  apparatus, the  thickness of the  vessels
and  cavities of the heart, impede  the view of  the blood
which they contain ; and experiments  made without an
absolute- inspection of the fluid  there,  can only  give us
approximations.  The  indecisive experiments  of former 
 254          PHYSIOLOGICAL RESEARCHED

 physiologists on this  subject were  my motives for the
 present inquiry.
   One of the best methods of judging of the colour of the
 blood, consists as I have often  said, in fixing a tube with
 a stop-cock to the trachea.  By this, the influx of air into
 the lungs, may be  regulated or altogether stopped.  By
 this, we may distend the organ, or entirely evacuate it;
 it gives us  also  the facility of introducing whatever gas
 we please.  The animal breathes very well by such pipe
 when it is open,  and would live with it for a considerable
 length of time  vvithout any very great alteration in its
 functions.
  In the second place, an artery, the  crural or carotid for
 instance, must be opened with  the view of observing the
 varieties of colour  in. the  blood projected from it.  A
 small artery should  not be chosen.  From such a one the
 course of  the blood would be suspended by the slightest
 accident;   and on  the other hand,  the larger  arteries
 expend in a little time too large a quantity of blood; this
 inconvenience may  be remedied, by adapting to these
 vessels a tube of  a small diameter, or a stop-cock.
  All things being thus prepared, on a dog, for instance,
 let us see  what are the phenomena which take place, when
 the colour of the blood  is altered.   In my  indication
 of. these,  however, I shall  speak only  of what I  have
 seen, and  by no means pretend that in man their duration
 should be  similar or uniform, or even that  in  animals
 of the same species,  under the  different circumstances of
 sleep,  digestion,  exercise,  and  passion, &c.  if  it were
possible in such way to repeat them, they should be alike.
The instability of the animal functions, as  I have said, is
extreme ;  they cannot  be submitted to calculation ;  they
remain indeed the same, but their variations as to.plus or
minus are innumerable. 
ON  LIFE AND DEATH.
255
   Let us now return to our subject :
   1st. If the cock of the'pipe be shut immediately after
the animal has inspired, the blood begins to be altered in
colour at the end of about  thirty seconds.—At  the end
of a minute  its colour is dark ;  at the  end of a minute
and  half or two minutes, it is perfectly similar to venous
blood.
   2dly.  If the cock of the pipe be shut immediately after
the  animal has expired strongly,  the blood receives its
tinge of black some seconds the sooner.
   3dly.  If the  air of the lungs  be pumped out entirely
with a syringe, the blood will suddenly pass from red to
black.*   In  such  ease it appears  that  the artery  immedi-
ately throws out a black stream,  after it has expelled the
red  blood which  it previously contained.   There  is no
gradation.  The blood is expelled by the arteries, such as
it is in the veins.
   4thly.  If,  instead of making  a  vacuum in  the lungs,
we inflate the air cells  to the full, the  blood is  a longer
time in becoming  black, a minute at least, and is not com-
pletely black before the end of three minutes.—This will
vary according to the quantity of air injected.
   From  all  these  experiments it follows,  1st, That  the
length of the  interval, during which  the blood retains
its red colour, is  in direct  proportion to the quantity of
air contained in the lungs ; 2dly,  That as long  as there
remains  any quantity  however small of respirable  air in
the  cells of  the lungs,  the  blood will  preserve  more or
less  of its crimson colour;  3dly,  That this colour dimin-
ishes in proportion as  the respirable air diminishes ; and

  * It is not possible to remove by this  means a great portion of air
contained in the lun^s, for the last ramifications of the air-tubes being
flexible, their parietes. soon come in contact, and thus oppose the  exit
of the air contained in the bronchial cells. 
 256          PHYSIOLOGICAL RESEARCHES

 4thly, That the blood is  exactly similar  to  that of the
 veins, as soon as the whole of the vital air in the extremi-
 ties of the bronchiae has been exhausted.
   In my different  experiments with regard to asphyxia,
 I  have remarked, that if after  shutting the cock of the
 syringe, the animal  agitate the chest by simil-ir move-
 ments to  those  of inspiration and  expiration, the blood
 is a longer time in losing its red colour, than  in  the case
 where the  breast  remains  at  rest.  Such  motion  and
 agitation  must  cause a circulation of air  in the  cells, in
 consequence of which,  a  greater  number of its points
 must be presented to  the circulating fluid.  My experi-
 ments which I shall presently detail on the breathing of
 animals in  bladders, will prove the truth of the above
 explanation.
   At present I  pass to a contrary set of phenomena—to
 those which are exemplified when the blood regains its
 arterial  colour during the  period, which, from a state of
 asphyxia,  restores the  animal to life.
   1st. When the cock, which for some minutes has been
 shut, is opened, the air immediately penetrates into  the
 bronchiae;  but previously  the  animal  expires strongly.
 Six or seven  large  inspirations and expirations follow
each other precipitately.   The artery being now examin-
 ed, a jet of a very vivid  colour  is seen  succeeding to the
 efflux of black blood, and takes place in thirty seconds at
 most, from the time  of opening the tube.   This is the
 inverse of the phenomenon above described.  There are
 no  successive  shades perceived from black to red ;  the
passage  is  instantaneous.   The  brightness of the colour
seems even to be greater than is natural.
  2dly. If instead of  suddenly turning the cock, a very
strong stream of air only be admitted, the colour is less
lively indeed,  but just as quickly regained. 
ON LIFE AND DEATH.
257
   3dly. If there be adapted  to  the stop-cock a syringe
full of air, and this fluid  be  pushed  into  the lungs, on
opening  the  pipe,  and then the  pipe be suddenly  shut
again, the blood will become red, but much less evidently
so, than when the entrance of the air is owing to  volun-
tary  inspiration.   Here  the portion of air injected must
repel into the bottom of the cells whatever is already
vitiated, while  on the  contrary, if the  tube be simply
opened,  the  vitiated  air  is at once  rejected, and  then
replaced from  without.   The  following  experiment ap-
pears to confirm this idea.
   4thly. If instead of  pushing air upon that which is con-
tained in the lungs, we  pump out  the vitiated air  in the
first  place, and then inflate the organ, the colouring pro-
cess  will  be more rapid, and the colour of  the  blood
itself especially, more lively  than in  the preceding case,
though less so than in  the first of this latter suite of expe-
riments.
   5thly. The lungs being exposed  on both sides by  a
lateral section of the ribs, the circulation  will continue to
go on for a certain  time.   Now,  if by means  of a syringe
adapted to the stop-cock  in  the  trachea, the pulmonary
vesicles be alternately emptied and  dilated,  the changes
from red to black,  and from black  to red, will be observ-
ed as in the above  experiment, as  long as the circulation
lasts.
   The following consequences may be inferred from the
facts, which I have mentioned.
   1st.  The rapidity with which the  blood  becomes red
again, on opening the pipe in  the trachea, is a plain proof,
that  the principle from which  this colour is gained,  must
pass  into the blood across the membranous parietes of the
air cells,  and  not  by means of the absorbents.   I  shall
establish this fact hereafter upon  other proofs.
              33 
258
PHYSIOLOGICAL RESEARCHES
   2dly. The celebrated experiment of Hook,  in which
the enfeebled movements of the hearts of animals in a
state of asphyxia are accelerated by injecting air into the
lungs, is very well explained.  The red blood penetrates
into the fibres of the heart, and puts an end to the debility
induced, by the influx thither of the black blood.
   3dly. I do not believe, that motion can ever be restored
to the heart, when once it  has  been wholly  annihilated
by the presence of venous  blood.   In this  I have never
succeeded,  though I have often  attempted  it.   Many
authors, however, pretend  to have done so.  If the heart
be reanimated  by arterial  blood,  it is necessary at  any
rate, that  such  blood, should pass  into it, now in what
way can it  arrive there, if the circulation  have entirely
ceased.
   We must observe, however,  that  there are  two cases
of interruption in the action  of the heart from  asphyxia.
Sometimes there  supervenes a syncope which arrests the
movement of this organ, before the black  blood has been
able  to produce  such  effect; and  here it is manifestly
capable of excitement, from the presence of the red blood,
just as it is  from  the application of any irritating cause ;
but when it has been injected with venous blood, it then
contains  within itself the principle of its  inertia, which
can be removed only by the contact of arterial blood with
it; but such contact is become impossible.
   I was very desirous of knowing  what  the  influence
might be  of the  different gases when inspired  upon the
colour of the blood.  Accordingly I successively adapted
to the pipe different bladders, containing  hydrogen and
carbonic acid gas.
   The animal alternately swells and cantracts the bladder
by the different motions of the thorax.   It is calm at first,
but at the end of three minutes, begins to be agitated; its 
ON LIFE AND DEATH.
259
respiration is  now hurried  and embarrassed, and at the
end of four or five  minutes, the blood of the carotid is
black.
  Whichever of the  two gases be employed, there is little
difference in the above phenomena.  This remark should
be compared vvith those of the Members of the Institute,
who have assured us that complete  asphyxia supervenes
only after an interval of ten minutes, with pure hydrogen,
and at the end of two  minutes with carbonic acid gas.
The black blood must continue, therefore, to circulate for
a longer  time  in  one than in the other  kind of asphvxia
here spoken of.   This circumstance confirms some reflec-
tions which I  shall have occasion to  offer upon the differ-
ence of asphyxiae.
  For what reason  should the blood be a longer time in
losing its colour, when  bladders of non-respirable air are
fixed to the pipe, then when the cock is simply turned ?
The reason of this is evident.   By the different  motions
of the lungs, the air is expelled and reabsorbed,  the  res-
pirable portion of it must consequently be successively
presented to the capillary orifices, by which it is trans-
mitted to the blood.
  On the contrary,  when the pipe is simply shut, the air
it is plain has  not the same influx and efflux ; in compari-
son with such motion, it may  be said to stagnate so that
the respirable portion of that  which is enclosed in the
bronchial cells is exhausted, and the blood ceases to be
coloured, though  there remain in the trachea and it-, larger
divisions, a  considerable quantity of fluid, which has not
been  despoiled  of its  vivifying principle.   Of  this we
may be certain, after the death of the animal, by  cutting
the trachea  under the pipe, and plunging a bougie  into
it.  The process  by  which the blood gains its red colour
appears  to  take place only  at the extremities of the 
260         PHYSIOLOGICAL RESEARCHES

bronchiae, the  inner  surface of the larger aerial vessels,
has nothing to do with this phenomenon.
  We may convince ourselves of the reality of the expla-
nation which I have  offered, if  we pump out the air of
the lungs, before we  fit the bladder to the trachea ; for in
such case, the  animal must breathe the air of  the bladder
without mixture.   Here the change of the blood to black
is almost sudden, but here also, as in the preceding experi-
ment, there is little difference in  the phenomena, whatever
gas we employ.  I have chosen the two gases above men-
tioned, because they  enter into the phenomena of natural
respiration.
  When we adapt  to the  pipe a  bladder full of pure
oxygen, the blood is very  long  in  becoming black, but
does not at first assume a redder tint than it usually has.

II.  The blood which has been blackened in consequence
  of the interruption of the chemical functions of the
  lungs penetrates into the organs, and circulates for
  some time in the vascular system (f the red blood.

  We  have just established what are the phenomena of
the alteration of colour in the  blood, when the chemical
functions of the lungs are suspended.   Before  we consider
the influence of this  change upon the death of the organs,
let us prove, that they are really penetrated by the blood
when so altered.
  I have proved it to be a fact, that the force  of the heart
subsists for some time, notwithstanding the influx of the
black blood  into it, and have shewn that the  black blood
is thrown out wnth a jet, similar to that of the red blood",
&c. &c.  Hence I  might already conclude,  1st, That the
arterial  circulation  continues for a certain time, though
the arteries  contain a fluid, to which they are not accus- 
ON  LIFE AND  DEATH.
261
lomed, and 2dly,  That the necessary consequence of such
circulation, must be the injection of the different parts of
the body with black blood; but we shall deduce the latter
conclusion from  precise and  rigorous  experiments.  To
be certain of this  important fact, we have only to expose
successively the different organs, while the animal is suf-
fering a death of asphyxia.  I have in this way examined
the muscles, the nerves, the membranes and the viscera.
The following are the results  of my observations.
   1st. The colouring matter of the muscles, exists in the
body in  two states—at liberty, or in a state of combina-
tion ; in the vessels, where it circulates with  the  blood,
or  in the fibres,  with  which it is  combined.  It  forms
especially the  colour of the  muscles,  and  in such  state
undergoes no  alteration from asphyxia ; in its free state
it is blackened.   The divided muscles  furnish an  infinity
of  black drops, which  are  no other than  indices of the
divided  vessels.   Such drops contrast with  the  red of
the  muscles;  but when circulating within them, are the
cause of that livid tin  which they then present.
   2dly.  The nerves are habitually penetrated by a number
of small arteries,  which creep along within their tissue,
and carry to them both excitement and life.  In the state
of asphyxia the black blood by which they are traversed,
is announced  by the dull  brown, which succeeds to the
rosy-white, which is natural to them.
   3dly.  There are few parts, where the influx of the black
blood is more visible, than in the skin  ; the livid spots so
frequent in asphyxia, are only the effect of the obstacles
which it meets with, in its passage  tovvards the general
capillary  system, to the organic contractility of which it
is not a sufficient excitant.   To this cause also is  owing
the tumefaction  of certain parts, such  as  the cheeks and
lips.  This phenomenon  we have  seen already  in the 
262
PHYSIOLOGICAL  RESEARCHES
lungs, they cannot be traversed by the blood and therefore
become in the last moments of life, the seat of  a fulness,
which affects the whole of the capillar)' system there; but
for the  reasons, which I have assigned, such  fulness is
always more evident in the capillary system of the lungs,
than in that of the system in general.
   4thly.  The mucous membranes also, when the chemi-
cal functions of the  lungs  are interrupted, exemplify a
similar phenomenon.  The swelling of the tongue, ob-
servable in those that have been drowned or hanged, or
asphyxiated by the  vapour of charcoal, the lividity of
the membrane of the mouth,  of the intestines, and the
bronchiae which have also' been  remarked, depend  on
no other cause.  The following is a proof of this asser-
tion :
  Drag out of an animal a portion  of the alimentary canal
and divide it in such way as to expose  its inner surface.
Then  shut up the  pipe which has been previously adapted
to the trachea, and at the end  of four or five minutes, a
brown tint will succeed to the red one, which is natural
to this surface.
  5thly.  I have made the same remark upon the fleshy
granulations of a wound, inflicted on  an animal, for the
purpose of observing the manner in which they are colour-
ed by the black blood.  In  the two  last experiments, this
phenomenon is slower in taking place than in many other
circumstances.
  6thly.  The  alteration  of  colour  in the  serous mem-
branes is  much more quickly effected than it  is in the
mucous membranes.   Of this we may assure ourselves by
comparatively examining the outer and inner surfaces of
the intestines, while  the  pipe  in the trachea is  shut;  in
the serous membranes, the livid tint which  they assume,
depends upon the vessels, which creep underneath them, 
ON LIFE AND  DEATH.
263
and  not on  the blood  by which they  are  penetrated.
Now as  these vessels are considerable, the black blood
must flow  into  them almost as soon as  it is produced.
In the mucous  membranes on  the contrary,  and in all
cicatrices, the colour which they take on in asphyxia, is
made by the capillary  system  of the membrane itself,
which system  is  much more tardy than  the other,  to
receive the black  blood, and to be penetrated by it ;  so
much  so indeed, as to refuse it in some parts.   I have
many times seen the  membrane of the nasal  fossae very
red  in asphyxiated  animals, while that of the mouth has
been quite livid, for there are parts into  which as I have
said  the black blood will not penetrate  at all, and  then
they preserve  their  natural  colour.   2dly.  There  are
others into which it evidently passes, but where it stops,
and  then a simple change of colour is observed, if it hava
penetrated but  in  small quantity ; and  again, if it have
penetrated in a considerable quantity, together with  such
change of  colour, there  will be  observed  a  tumefaction of
the part.  3dly. In other cases, the black blood merely
traverses the parts,  without stopping in the  capillary
system,  and passes at once into  the veins, as the red blood
does.
   In the first  and  second case,  the  general circulation
experiences  an  obstacle which  puts a  stop to it in the
general  capillary system.   In the  third, which  is much
more universal, it is in the capillaries of  the lungs that
the  blood is at last arrested, after having circulated in the
veins.
   These two  sorts  of impediment coincide vvith  each
other, in many instances.  Thus  in asphyxia, a  part of
the  black  blood  which  circulates in  the  arteries stops
in the face, upon  the mucous surfaces,  in the tongue, and
in the lips, while the other, and much the larger quantity, 
264
PHYSIOLOGICAL RESEARCHES
finds no impediment in the  general capillary system, and
is finally arrested in  the lungs.
  What is the  reason, why certain parts of the capillary
system refuse to admit the venous blood, or if they admit
it, do not pass it on  to the veins; while  others are less
enfeebled by it, and transmit it  as freely as ever.   All
this must certainly depend on the relation existing between
the sensibility of each part and  the venous blood.
  I was desirous of  making use of the power, which we
possess, of  changing the colour of the blood, for getting
some insight into  the influence of the circulation of the
mother, upon  that of the foetus ; accordingly I procured
a bitch big  with young, and asphyxiated her, by closing a
tube, adapted to the  trachea.  About  four minutes  after
she had ceased  to breathe, I opened her ;  the circulation
was going on.  I then cut into  the matrix, and exposed
the cord of  two or three of the foetuses.   The artery and
the vein, were both of them  full alike of  venous blood.
  Had I been able to  procure  other  bitches  in a  similar
state, I  should have repeated this experiment in another
manner.  I  should  in  the first place  have compared the
natural colour of the vein, with  that of the  artery.   In
many of the  young of the guinea  pig,  the difference
appeared to  me to be much less than  it is  in the adult
animal.   In many circumstances indeed I could perceive
no  difference  whatever.  Both  the  arterial  and  venous
blood were  equally black, though the respiration of the
mother was in no wise impeded by the opening of the belly.
Secondly, I should have closed the tube in the trachea, and
then have observed  whether the change in colour of the
umbilical'artery of the foetus (supposing the blood of the
artery to be different from that of the vein) were  corres-
pondent with  that, which would inevitably take place in
the  blood  of the mother.   Experiments made  with a 
ON LIFE AND DEATH.
265
view to these circumstances, and on large animals, might
probably throw much light upon the mode of communi-
cation, between the mother and the foetus.  Observations
are also much to  be desired, with respect to the colour of
the blood in the human  foetus, and the cause of its  passage
from  a livid  colour, to the  very  marked  red which it
assumes, some little time.after birth.*
   I might add a number of examples  to  these, which I
have already related of the blackening of the organs by
the venous blood.  Thus, the kidney of a dog exposed,
while  the animal is  dying of  asphyxia,  is  much  more
livid than in its natural  state, the spleen also and the liver,
when  divided, emit  only  black  blood, instead  of that
mixture of red and black  blood which  is observable, in
the section of these organs, upon an animal which breathes
freely.
   But I trust that we have facts enough to establish it as
a certainty, 1st,  That the black blood after the interrup-
tion of the chemical functions of the lungs,  continues for
some time to circulate, afid 2dly, That  it penetrates into
the organs, where it replaces the red blood ; these circum-
stances explain the reason, why on opening the body we
always meet with black blood  even in  the vessels which
are destined  for the circulation  of arterial blood.
   In the last moments of existence of whatever  death
the individual may have died, we shall always observe the
lungs  become  embarrassed and cease  to perform  their
office, for some  time previous to the total suspension of
the  functions of the heart.   The  blood makes its circle
 through the system, after ceasing to receive the influence
of the air, and consequently in  its venous state; accord-
 ingly it must remain so  in the organ in every case, although
   * These  observations hive be< n  made on the great  mammalia, and
 there has not been remarked any difference of colour.
              34 
266           PHYSIOLOGICAL RESEARCHES

the circulation be much less evident, than in asphyxia, for
it is in this circumstance that consists, the great peculiarity
of asphyxia.   The  following phenomena  may now be
easily understood.
  1st. When the left auricle and ventricle together vvith
the large  divisions  of the aorta, on  opening the body,
are found  to contain blood, such blood is  always black.
The  fact  is familiar  to  those who  ;;re  in the, habit  of
dissecting. In exercising my pupils on. the surgical opera-
tions, I have always observed that when the open arteries
are not entirely empty,  their contents are composed  of
venous blood.
  2dly, The  corpus cavernosum is  always gorged with
this sort of fluid, whether flaccid or in a state of erection.
For I  have seen it  in the latter state in two subjects
brought to my  amphitheatre.   One  of  these men  had
hanged himself, the  other had died of concussion of the
brain.
  3dly, The blood which is found in the spleen is never.
red ;  but  sometimes on  the exterior, and  sometimes on
the concave  surface of this organ, I have  observed spots
of a scarlet colour, for which I cannot account.
 ' 4thly,  After death, the mucous membranes lose the
red colour by which they are characterized  during life.
They assume a black and livid hue.
  5thly,  Blood  extravasated  in  the brain of persons in  a
state of apoplexy, is almost always found to be black.
  6thly,  Sometimes, instead  of accumulating inwardly
the blood injects the surface  of  the body.   In such  case
the face, the neck, and shoulders swell, and are infiltrated
with  blood.   I  have frequently remarked this  sort  of
phenomenon in the  subject, but have never found it coin-
cide with  any internal extravasion.—The colour of the
skin is then of a purple  or deep brown, an evident sign 
ON LIFE AND DEATH.
267
of the sort of blood  with  which  it is injected, and is
evidently produced by the  stagnation of the black blood
in.the external capillary system, not by the reflux of the
blood from the veins.
  I shall not dwell any longer upon the numerous conse-
quences of the above established principle.  I shall only
observe, that when death commences  by the circulatory
system, the preceding phenomena are not to be remarked,
or at least very little perceptible.
  Let us now pass on to the influence  of the black blood
upon the organs  of which at penetrates the tissue.

III. The  black  blood which penetrates the organs, as
   soon  as the  chemical functions of the  lungs havje
   ceased, will not maintain them in  a state of life and
   activity.

   To determine what the  influence of the black blood is
upon the organs, I shall first remark, that the property of
the red blood is to stimulate them, and keep up their vital
actions.   This will  be proved  by the  following observa-
tions :
   1st, Compare  phlegmon, erysipelas, and  inflammatory
tumours  (to the  formation  of  which  the  red blood is
essentially requisite) with  scorbutic spots, and petechia?,
produced by the  black  blood.  The  first will  be  found
connected with  the exaltation  of the vital  powers, the
second vvith their depression.
   2dly, Examine two men, the one vvith a rosy coloured
skin and large breast,  announcing vigour of lungs, the
other with a pale  and sallow countenance, and narrow
 chest:  in these the vigour of the chemical combinations
 which  are made  in  the lungs, should certainly be very
 different. 
268          PHYSIOLOGICAL RESEARCHES

   3dly, The greater number of gangrenes in old' men,
begin  with  a lividity in the  part, a lividity  which is
evidently  the index of the absence or diminution of the
arterial blood in the part.
   4thly, The redness of the branchiae of fish  is always
the sign by  which their vigour may be recognised.
   5thly, The redder the  granulations  of wounds,  the
more healthy is their nature ; the paler or browner they
are,  the less has the part a tendency to cicatrise.
   6thly, The lively  colour of the face, and  the ardent
eye, coincide with  the energy, of the cerebral actions in
Certain fevers.
   7thly, The more developed  the pulmonary system of
animals, the more active  are the chemical processes of the
lungs, and the  more developed  and perfect the general
life of their different organs.
   Sthly, Youth, which  is  the  age of vigour, is that also
when the red  blood predominates in  the system.   The
arteries of old  people are  smaller, the  veins  larger than
those of the young.   It is a fact universally known, that
at the two extremities of life the proportions of the two
vascular systems are inverted.
   I  am ignorant of the  manner in  which the red  blood
excites and  keeps up the life of the parts.   Perhaps the
principles by which it is  coloured become combined with
the different  organs to which  it is distributed.  In fact
there is a considerable difference between the phenomena
of the general and those  of the  capillary system.
   In  the  first,  the  blood in  changing its  colour, leaves
behind it the principles which made it red; in the second,
the elements to which its blackness is owing, are rejected
by respiration and  exhalation.   Now, this union of the
colouring principles of the arterial blood, may  probably
constitute  a material part of  the  excitement which  is 
ON LIFE AND DEATH.
869
necessary to  the action  of the organs.—If such be the
case, the black  blood as it does not contain  the materials
of such union, cannot act as an exciting cause.  This idea,
however, I offer only as a  probability, and am by no
means prepared  to defend it as a truth; it may be ranked
on a par with that of the sedative action, which I have
said  may be excited  by  the black blood on the different
parts—-for, however  probable an opinion  may  appear,
there should 'be no  real importance  attached to it as an
opinion only.
  Without regard  then to  any system, let us  inquire
how the black  blood, from  its  contact with  the various
parts, is the occasion of  their death ; how it  acts on  the
parts of  the animal life,  and how it acts on those of the
organic life.
  All  the organs of the animal life depend upon  the
brain ; now,  we have seen that the black blood paralyses
the cerebral  powers  almost suddenly.  In the state  then
of asphyxia, the  locomotive, the  vocaj  and  sensitive
organs, must be inactive.   From the same cause, their
exercise must be suspended in all those different experi-
ments where black  blood is injected into  the brain, the
other parts receiving the red blood as usual.  But when
the  black blood circulates  throughout all  the  system,
when the whole of the organs,  as well as the brain, are
submitted to  its influence, then there are two other causes
of death connected with those which have been mentioned.
  1st,  The nerves, which are penetrated  by it,  for that
Very reason are  no longer capable of keeping up the com-
munication between  the brain and the senses on the one
hand, and on the other, between  this  same viscus and the
locomotive or vocal organs.
  2dly,  The contact  of the black blood with these organs
themselves annihilates their  actions.   Inject the crural 
270
PHYSIOLOGICAL RESEARCHES
artery of an animal with the black  blood taken from one
of its veins, and  the movements of that  member will be
shortly afterwards enfeebled,  or wholly paralyzed.  In
this experiment,  the upper part of the artery, for manifest
reasons,  should be that to which the  pipe of the syringe
should be fixed.
  I am aware that as to this experiment,  it may be assert-
ed that  the  ligature of the- artery, of itself,  is capable
of paralyzing the  limb.  In fact, such circumstance has
happened twice vvith me, but I have also had  occasion to
observe, that it  does not  necessarily follow the ligature
of this vessel, as it does the ligature  of  the aorta : when
the latter vessel  is tied, all  movements cease at  once ;
notwithstanding  all which, the  result of the injection of
black blood, is almost constantly that  which I have assert-
ed it to be ;—I say almost,  1st, Because  I have once seen
it fail in  its  effect, though done with the  requisite precau-
tions;  2dly, Because the debility, which is induced, both
in duration  and degree, will be according to the strength
of the animal on  which  the experiment is made.
  There is also occasioned in this experiment, a manifest
suspension  of  the sensibility  of  the animal ; it  is not
indeed so ready  to appear as  the  loss of motion ;  but it
always comes on, especially if the injection of the black
blood be repeated three or four times,  with small intervals.
  A similar, but a more  tardy effect may be produced
by adapting to the canula, which  has been placed  in the
crural  artery of  an animal, a  tube  which has  been pre-
viously fixed to  the carotid of another  animal, and then
by asphyxiating  the latter.*   The organs of the internal

  * The difference that is remarked in the results oL-this experiment,
compared  with that in which the venous blood is  introduced by means
of a syringe, arises probably from this, that in the  first the blood that is
forced into the artery has already begun to coagulate. 
ON  LIFE AND DEATH.
271
life are not  dependent on  the brain, and  therefore are
not affected  by the  suspension of the cerebral action in
asphyxia.   It is the influx of the black blood which is the
immediate cause of their death,
  I have  already demonstrated what  the  influence is of
this blood upon the  organs  of  the circulation.   We have
seen how  the heart ceases to act, as soon as it is  penetrated
by it; it is owing in part to the injection of the arterial
and venous parietes themselves, by the vasa vasorum, that
the vessels are forced to suspend their actions.
  It will  be  always a  difficult thing to prove, that the
secretions, the exhalations,  and the process of nutrition,
could not be  made from venous blood, because the circula-
tion of this sort of blood in the arteries, does not continue
for  a sufficient tim-e,  to allow of observations,  or the
manner in which these  functions would be affected by it.
On this subject, however, I have made some essays.   1st,
I exposed the inner surface of the bladder of a  living
animal, after having previously  divided the  symphysis
pubis, and opened the  lower belly, I then  examined the
oozing  of the urine from   the orifices" of the ureters,
while I asphyxiated  the animal.  2dly, I divided  the vas
deferens,  with the view of observing, whether  the semen
would flow or not, during such state.
  In general, I have had occasion  to remark, that  during
the circulation of the black blood in the arteries, no fluids
appear to  issue from  the different secreting  tubes.   But I
confess, that  in all these experiments, and in other similar
ones which I  have made, the animal is too much agitated,
and the limits of the experiments too circumscribed, for
any thing like a well  founded judgment  to   be  formed
on the  subject in  question.   It is  chiefly from analogy,
then,  that I am  led to  conclude, that the black blood is
unfit for the  purposes of exhalation and nutrition; such 
272           PHYSIOLOGICAL RESEARCHES
supposition  also  accords well vvith  divers of the  phe-
nomena of  asphyxia.—1st, The want of  exhalation from
the  skin during  the state of asphyxia,  is probably the
reason of the phenomena of the animal heat in such sort
of death.*   2dly,  In  asphyxiating  animals very slowly
during  digestion, I have uniformly observed, that the bile
ducts, and duodenum, contain a much less  quantity of bile,
than they do at such  time, when these parts are exposed
in the living animal.—-3dly, As the blood  loses nothing
from  the exercise of these functions, it  must  of course
accumulate  in the vessels ; and in fact it is very fatiguing
and  unsatisfactory, to dissect the  bodies  of those  who
have  been  hanged or asphyxiated  with  the vapours of
charcoal, from the fluidity and abundance of their blood.
But  this abundance,  perhaps, may depend  upon  the
weakness of the absorbents.  In other sorts of death, the
absorbents continue for some time to act  upon the serous
portion  of the blood remaining in the vessels. In asphyxia
there is neither secretion nor absorption.
  The excretions  also appear to be  affected much in the
same  way.   The bladder of asphyxiated persons has been
observed  by Portal,  to be very much  distended.   Such
distension, no  doubt  is occasioned  by the  urine  already
secreted before the accident which was the cause of their
deaths.   In general, the  asphyxias  which are occasioned
by the circulation  of the black blood unmixed with  any
deleterious  substance,  are not accompanied  with those
spasms, which  in  so  many other sorts of  death, are  so
  *The deficiency of cutaneous exhalation in the last moments of life
may contribute a little  perhaps to the preservation of animal heat ; but
we have shown that there are other more powerful causes for this phe-
nomenon. This deficiency of exhalation united to  the inaction of the
secretory organs, in the very short period in which the black blood runs
in the arteries  is an altogether insufficient cause to explain the abun-
dance of  blood that is found in the vessels of those who have died of
asphyxia. 
ON  LIFE AND DEATH.              273
frequent.   These spasms,  which  evacuate the  organs of
their  fluids,  should be  carefully distinguished  from the
simple relaxations of  the sphincters,  by which analogous
effects are produced.*   In asphyxia,  all is  debility,  in
asphyxia,  we  never  see  that  augmentation of life,  that
development  of  power, which  so  frequently mark the
latter movements of the dying.
   Hence also perhaps, the great flexibility of the members
of asphyxiated persons.  The stiff.ess of the  muscles
appears to depend  in  many cases, on  the circumstance of
death having come on precisely at the moment of their
contractions.   The fibres remain approximated, and cohe-
rent among themselves ;t in asphyxia, on the  contrar)', as
there exists an universal relaxation  and want  of action in
the parts, they remain so after death, and yield to what-
ever impulse may  be  communicated to them,
   I confess,  however, that this explanation is subject to a
difficulty  which I cannot solve.  Persons asphyxiated by
mephetic  vapours, perish nearly in  the same way as those
who are drowned ; if  the cause of .their death  be different,
its effects are the same, as may be seen  by  opening the
carotid of two dos;s at the same time, that into  the lungs
of the one are injected the vapours of charcoal, and into
those of  the other,  a certain  quantity of water,  which
water, as  in  the drowned, is soon  reduced  into a state of
foam.

  * This is not  an uniform fact, and it is even very common to find, in
persons who have been hung, the bladder completely empty.
  + The moment  respiration ceases, and the  source of  heat' is conse.
quently cut off, it is not astonishing that an animal body  should  become
cold quicker in  water then in a much less dense fluid, like the air.  It
should also be remarked that the water, on  account of the evaporation
that takes place on its surface, has almost always a temperature below
that of the surrounding air.
              35 
274
PHYSIOLOGICAL RESEARCHES
  Notwithstanding this similitude of the last phenomena
of life in the two cases, the members in the first remain
for  a certain  time  warm and supple, while those  in  the
second, especially  if the  body  be plunged  into water
during the experiment, become  very suddenly  stiff and
frozen.   Let us return, however,  to  our subject.  We
may conclude from  the various  facts and  considerations
related  in  this  "hapter,  1st, That when the  chemical
functions of the lungs are suspended, the functions of all
the  other organs are suspended  also, from  the  presence
of black blood  within  their substance.   2dly, That  the
death of the organs in general, coincides  with that of
the  brain, and the heart, but is not immediately derived
from them.   3dly,  That if it were possible for-the brain
and heart to  receive an influx  of  arterial  blood, while
the  others were dying, from  that  of  the venous  blood,
they would doubtless continue, to exert their accustomed
actions.  4thly, That,  in a word, asphyxia is a general
phenomenon, developed at the same time in all the organs,
but  especially in one of them.
  From  this manner of regarding  the influence  of  the
black blood upon the different parts of'the bod}7, it appears
that death is  very soon the result of its circulation in- the
arteries.   Nevertheless, ' certain organic defects have
sometimes prolonged after birth, the mixture of the two
sorts of blood,  a mixture which  is known to be made in
the  foetus.   Such  was  the malconformation  mentioned
by  Sandeford, in a child, the aorta of which arose by  a
branch from  each of the ventricles.  Such also appears,
at first sight, to be the opening of the foramen ovale in
the  adult.
  We shall  remark, however, that the existence  of this
foramen, does not  suppose  the passage  of  the  black blood
into the red-blooded  auricle,  as is generally  believed. 
ON LIFE  AND DEATH.              275
For the two semi-lunar valves, between which it is situ-
ated when  met with after birth, are necessarily applied to
each other  by the pressure which the blood contained in
the auricles, exercises upon them, when these cavities are
simultaneously contracted.  The foramen must be at such
time shut, and  its obliteration much more exact, than that
of the opening of the ventricles, by the mitral and tricus-
pid valves, or that of the aorta and the pulmonary artery,
by the sigmoid valves.   With all this, the  foramen ovale
is actually very often found open in the subject, and when
not so, nothing  is easier than  to destroy  the  species of
adhesion which is  contracted by  the two valves which
close  it.  This may be done with the handle of a scalpel,
without any solution of continuity, the parts appear to be
unglued.
  The oval hole when in this way artificially made, pre-
sents  the same disposition, with that, which is sometimes
exemplified in the carcase.  Now if this  disposition  be
examined,  it will be seen that when the auricles contract,
the blood  mu4  make an obstacle to itself, and  that it
cannot pass from one into the other of these  cavities.  It is
an easy thing to be convinced of the mechanism of which
I speak,  by means of two injections of a different colour,
made  at  the same time from both sides of the heart, from
the vena cava,  and  the pulmonary veins.
  From  what  we  have  said  of the  influence, which is
exercised by the movement  and the different principles
of the blood, it is  evident that the death of  the  white
organs  must  be different from  that  of  the  red  ones.
Asphyxia  can  hardly reach them,  but of  the manner in
which they die 1 confess that I know  but little. 
276            PHYSIOLOGICAL RESEARCHED
                     CHAPTER  IX.

 OF THE INFLUENCE  OF THE  DEATH OF THE* LUNGS, OVEK
           THE GENERAL DEATH  OF  THE  BODY.

   In recapitulating what has been said in the preceding
 chapters,  with respect  to  the influence of the lungs over
 the heart,  the brain, and  all the organs, it is an  easy
 matter to form an  idea of the  successive  termination of
 the whole of the functions, when  the phenomena of respi-
 ration are suspended  either mechanically or chemically.
   The following is the manner in  which death supervenes,
 when  the mechanical  phenomena of the  lungs are inter-
 rupted, either  from the  causes  mentioned  in  the  5th
 chapter,  or from  similar ones, such as the rupture of the
 diaphragm, which I  have twice had occasion to observe,*

  * When the diaphragm is ruptured, a sudden cessation of the functions
 is not always the result of this accident.   Patients have been known to
 survive many days, and the cause of death has only been ascertained
 by examining the body.
  The intercostal muscles are, in this case, the sole agents of respira-
 tion, which  becomes  nearly analogous to that of birds  or  to that of
 animals  with red and cold  blood, who  are destitute of  the septum
between the thorax and abdomi n.f
  Lieutaud cites various ruptures of the diaphragm, produced by other
 causes than external injuries.  Diemerbroech has seen this muscle want-
 ing in an infant who still lived to the age of seven years.

  f When from any cause, the diaphragm  cannot contract, the enlarge
ment of  the thorax is effected solely by the  elevation of the ribs, and
as  this motion is then very evident, we can then appreciate  better
the influence the intercostal muscles have in its production  in ordinary
respiration.  Haller, as is  well known, supposed that the first rib was
 almost immoveable, and that  the muscles in the first intercostal space,
took it as their fixed point to elevate the  second.   This second rib, in 
ON LIFE AND DEATH.
277
or from a fracture of a great  number of the ribs, or the
sternum.
   1st.  The mechanical functions of the lungs cease.  2dly.
The  chemical fiunctions of  the lungs  cease  also.  3dly.
The cerebral actions are put an end to.   4thly.. The  ani-
mal life  is  interrupted.   5thly.  The general circulation
is interrupted.   6thly.  The capillary circulation is inter-
rupted.
   The phenomena of death, are differently concatenated,
when  they   begin  by  the  suspension   of the  chemical
functions  of the lungs :  which may  happen, 1st, From
breathing in  a vacuum :  2dly, From the obliteration  of
the passage*of the trachea, by  foreign substances introduc-
ed into  itj or by tumour from without, or strangulation
accumulation  of  fluid in  the  air  cells,  &c.;  3dly, From
different  inflammatory  affections,  schirrhi,  &c. of  the
cavities of the  mouth  or throat.   5thly. From want  of
respirable air, as  on the summit of high mountains.  6thly,


its turn, served as a fixed point to elevate the third, and thus-on to the
last rib.  But if we  observe  the mechanical phenomena of respiration
when the diaphragm does not contract, as is the case in diaphragmatic
pleurisy, we see that the fir$t rib is far from being immoveable.   Now,
we  cannot  conceive how the intercostal.?  which are  attached1  to its
inferior part, can, by contracting, assist in raising it.  Besides, in  order
to elevate the ribs, a very great resistance must  be overcome, and the
intercostal muscles are  too slender to induce us  to suppose that they
nre capable of effecting it.  The principal  agents of this motion then
are the anterior and  posterior  scaleni, which-are  distinctly seen to con-
tract in great  inspirations,  the supra-costales and the muscles of the
neck which attach it to  the sternum. We ought to  add  to these a
muscle, to which this use has never before been attributed ; I mean the
diaphragm.  This muscle in fact in its contraction tends to become flat,
from being concave  as it is  in inspiration.  Now, its  middle part in
depressing the  abdominal viscera experiences a certain resistance, and
tak< ?, as it were, from them a fixed point, by means of which it elevates
the base of the thorax to which its circumference is attached. 
 -75          PHYSIOLOGICAL RESEARCHES

 From  the introduction into the air cells, of non-respirable
 gases,  &c. &c.  In all  these cases, the following  is the
.order of the phenomena of death.
   1st.  The. chemical functions of the lungs are suspended.
 2dly. The functions of the brain- are interrupted.  3dly.
 Sensation, locomotion, the  voice, the  mechanical phe-
 nomena  of respiration cease.  4thly.  The  action of the
 heart, together with the general  circulation is annihilated.
 5thly.  The capillary circulation  is put, an end to, together
 with the  processes of secretion, exhalation,  absorption,
 and  digestion. ' Gthly. The  animal  heat of the system
 dies away.

     I. Remarks upon the differences of asphyxias.

   The influence  of the  black blood  as I  have said, is
always the great  agent  in  this double  sort of death,  but
it  is not  the  only one : if that  were  the case, the phe^
nomena of all the asphyxiae would  be  alike.   It is true
that in every.sort of asphyxia, the black blood ceases to
become red  blood, and circulates in the arteries, such as
it is in the veins ; but  notwithstanding the uniformity of
this phenomenon, there can be nothing more varied, than
the symptoms and progress of these accidents.  In some
of them, death is long  in taking place; in  others, almost
instantaneous : the  phenomena  developed  in the  last
moments of existence, are  alike  in none of them.   The
state of the organs, and that of the powers which they
preserve  after death, are as various. :
   1st,  Asphyxia ' varies with  respect  to its duration ; in
sulphureted hydrogenous gas, in nitrous  gas, and certain
vapours  arising  frftm privies and sewers, it is quick in
taking  place.   In carbonic  acid gas, azot, in pure hydro-
gen, water, and a vacuum,  its progress is slower. 
ON  LIFE AND DEATH.
279
   2dly,  Asphyxia  varies-with respect  to  its attendant
phenomena.   At times, the animal  is violently  agitated
and suddenly  convulsed ; at others, it appears to lose its
powers gradually ;  to pass into-a state of sleep, and fr<rm
sleep into a slate of death. In comparing the numerous
cffocts arising from the vapours of sewers, from  those of
charcoal, from the different gases,  from drowning, and
other causes of asphyxia, we find them almost as  various,
as the causes themselves.
   3dly.  The  phenomena  which make  their appearance
after death, are as variable.  Compare the cold  and frozen
carcase of  a'drowned man, with the remains of one who
has  been  suffocated.   Read  the result  of the  different
experiments of  the Institute, upon  the  affections of the
galvanic fluid  in the different asphyxise;  examine Halle's
detail of the symptoms which  accompany the  mephitism
of sewers ; approximate the numerous observations, which
are scattered about  in the works of Portal, Louis, Haller,
Troj-a, Pechlin, Bartholin, and Morgagni; repeat  the most
common experiments on the  submersion, strangulation,
and  suffocation  of  animals ;  and  you will  observe the
greatest difference in all these sorts' of asphyxia,  they are
each  of  them characterized, by a  peculiar state of the
bodies -of  the  animals,  which  have been  submitted to
the experiment.
   To inquire into the causes of such differences,  we must
first divide the asphyxiae into two classes.  1st, Into those
which Happen from the  simple  want of respirable air, and
2dly, Into those, where  to this first, cause is joined  also
that  of the introduction of some  deleterious substance
into the lungs.
   In the first class, the  immediate cause  of death, appears
to be  the simple presence of the black blood, in the vari-
ous parts of the body, the general effect of which is always 
280          PHYSIOLOGICAL RESEARCHES
   the same, in whatever manner produced; accordingly, the
•   attendant  symptoms and. secondary  results of all  these
   sorts of death, are nearly alike, their duration the same,
   and  if it varies, it varies only in consequence of the more
   or less complete interruption of the passage of air into the
   lungs.
    This  variety  in  the  duration  and  intensity- of the
   asphyxiating cause, may nevertheless occasion some vari-
   ety in the symptoms also; such as a greater or less lividity
   and  swelling of the face,  a  more or  less considerable
   embarrassment  of the  lungs ; but all  these  differences
   indicate only so many modifications of the cause.   1st,  A
   man who is  hanged, does not die as-a man who is suffo-
   cated by an  inflammatory tumour,  or a pea or bean which
   perchance  may have fallen  into the trachea.*   2dly, An
   animal  will  perish much more  slowly under a vessel  of
   air, than when the trachea is tied.   3dly, The symptoms
   of asphyxia, when occasioned  by a  great rarefaction of air,
   or by a suffocating heat, are  mUch less slowly prodaced,
   than where the cavity of the  lungs is opened.
    In all these cases the cause of death, namely the absence
   of red blood in the arterial  system, is simple and unique,
   but according to  the greater or less  oxygenation of the
   venous  blood, will be the appearances after death,-for the
   longer the  process of asphyxia endures, the less irritability
   will  there  be found in the system.
    But if the cause of asphyxia, have been the introduc-
   tion  of some deleterious fluid into the  lungs, then the

    * Asphyxia is not always the cause of death in those who are hung,
   there is sometimes connected  with it a  more efficient cause,  which
   consists in the compression of the spinal marrow.  This was formerly
   very  often observed in those who  had been executed, because the
   executioner in throwing them off gave a rotatory motion to the  body
   which produced the luxation of the first vertebra on the second. 
ON  LIFE AND DEATH.
2S1
variety of the symptoms will depend upon the difference
in the nature of the  fluid.   In these  cases  the  cause is
of two kinds: 1st, There is no red  blood in the system.
2dly,  A pernicious  fluid is present in the system.  All
the gases however do not act  as deleterious substances:
in pure hydrogen  for instance, the  animal perishes only
as it would from the want of respirable air.
   But when a man in descending into a common  sewer,
into a cellar, or into any place where putrid matters  are
accumulated, falls  into asphyxia at the moment when he
inspires their exhalations, and  when  such state is attended
with convulsive movements and extreme agitation, then
indeed, there must be something more in the cause of his
death, than a simple suspension of the chemical functions
of the lungs.
   In fact, together with the mephitic  vapour,  there con-
tinues to enter into the  lungs a sufficient quantity of air
to keep up life and its different functions.  2dly, Suppos-
ing  even  that the quantity of mephitic air  were such as
to leave no place  for the entrance of  respirable air, still
the death  ensuing  should  only be  gradual,  without agir
tation and convulsion, were it  occasioned  only by  the
absence of such air: now the very different way  in which
it supervenes, very evidently indicates the action  of a
deleterious substance, upon the animal ceconomy.*

  * By injecting into the veins different irrespirable gases, Nysten has
been able to dMinguish  the  effects which result  from the deleterious
properties of the gases  from  those which arise from the alteration of
respiration from a want of atmospheric air.
  Thus among the elastic fluids which he tried, he found sulphuretted
hydrogen, the deutoxide of azote, chlorine  and ammoniacal gas emi-
nently deleterious; for introduced in  sufficient quantity into the animal
economy they uniformly cause death, whilst others, such as  oxygen,
azote, hydrogen, carburetted hydrogen, carbonic acid, oxide of carbon,
and protoxide of azote do not produce death when introduced into tlje
              36 
282
PHYSIOLOGICAL RESEARCHES
   These two causes then  act  together, in  those asphyxiae
which are produced by  certain gases,  sometimes the one
predominates, sometimes the other.   If  the deleterious
substance be violent, it kills before the action of the black
blood can have produced much effect, if weak, it is the
black blood, which is  principally the cause of death.
   The asphyxiae then, which  are produced by the gases,
differ only, in consequence of the nature  of  the deleteri-
ous substance, which varies adinfinitum.   In some of the
aeriform fluids indeed it is supposed to be known, but  in
the greater  number of them it is not  so :* I shall notice
therefore in a general  way the effects, which  result  from
the action of  the  deleterious  substance, remarking at the

lungs, except by excluding the only  mixture, that can  support respira-
tion ; in no other way do they occasion death, at least in a sudden manner.
If however, they are thrown quickly into the blood vessels, they cause
death, but it  is mechanically and in the same way as  atmospheric air
would do it.  It should also be observed that these different gases do
not all act in the same way when they are  introduced  into the lungs ;
the gaseous oxide of carbon destroys animals much quicker  than  azote
or the protoxide of azote.  They die also quicker in the protphosphu-
retted hydrogen, and even in the carbonic acid gas.  There are also in
the action of deleterious gases certain anomalies which have not hitherto
been explained.  Nysten injected, at thiee  injections, into the veins of
a dog of middle size thirty centimetres of sulphuretted hydrogen.  The
animal after the first injection, was agitated, and made powerful inspira-
tions; the second produced convulsive motions and the third  apparent
death ; but the next day he was entirely well.   Now a less quantity of
sulphuretted hydrogen carried into the organs of respiration and  mixed
with five or six hundred times its volume of air, would infallibly destroy
the animal.

  *The composition of some  of these vapours is better known at the
present day ; but there are  others in  which our means of analysis have
been unable to detect the  deleterious  principle ; thus  in the  malaria,
which has depopulated  the country in the neighbourhood of P«.ome, our
chemists have as yet only found as constant elements, those which enter
into the composition of atmospheric  air. 
                 ON LIFE AND DEATH.             233

same time, that the symptoms by which they are display-
ed, are strongly or weakly marked, according to the a^e
and temperament of the individual.
   Deleterious substances introduced  into the lungs, to-
gether with  the mephitic vapours of which they form
a part, can act only in two ways.  1st,  By affecting the
nerves of the lungs, which re-act on the brain.   2dly, By
passing into the blood, and exercising their influence, by
means of the circulation on  the  various organs  of  the
system..
   I can  easily believe that the simple action of such a
substance on  the nerves of the  lungs, may have  a very
marked effect on the economy, and be capable of troubling
the functions of the system very sensibly ; much  indeed
in the same way as with  some individuals a mere odour,
or the sight of a hideous object, will occasion syncope, in
the same way  that  an  irritating enema will  suddenly
awake the system  into life, or the introduction of certain
substances  within  the stomach, will be  felt  throughout
the body, before such substances can have passed into the
circulatory torrent.  We meet  at every moment  wTith
examples of these  very remarkable phenomena,  produced
by the simple impressions of foreign bodies on the mucous
surfaces ; I cannot deny that deleterious  substances may
act in the same way upon the  nerves of the lungs, though
we must not exaggerate the sphere of this mode of action.*
   In  fact, I am not acquainted with  any one  example,
where the contact  of a  deleterious  substance with  a
mucous membrane, has been the sudden  cause  of death.
It may indeed be productive of such effect after a certain
time, but never at the moment  of its action ; neverthe-
less, in  those asphyxise which  are produced by mephitic
  * It appears from the experiments of M. Desormt-s that the contact
»f sulphuretted hydrogen on the ?kin of an animal is immediately fatal. 
284          PHYSIOLOGICAL RESEARCHES

vapour,  so rapidly does  death  come on, that the black
blood can scarcely have had the time to exert its influence
upon the body.   The principal  cause of the cessation of
the  functions is manifestly the  action of the pernicious
substance.
   These considerations, then, incline  me to believe, that
these substances pass into the  blood  through the lungs,
and  that in circulating  with the blood they carry to the
organs the immediate cause of their death.   Such passage
into the blood has already been  suspected  by  many phy-
sicians ; the  truth of the  fact appears  to  be indubitably
proved by the following reflections.
   1st, It can  hardly be doubted, that the  poison of the
viper and  many  other  venomous animals,  and that the
saliva of rabid animals, pass into the system of the blood,
and are taken up either  by the veins or the lymphatics.
   2dly, It appears to be very certain, that a portion of the
atmospheric air is actually absorbed  through the mucous
membrane of the  lungs  itself, and  not by  means of the
absorbent system.   Now, if this be the case, I know not
what should  hinder the  passage of  mephitic vapour in
the same way.*   We are not sufficiently acquainted with
the limits of the  particular sensibility of the membrane
of the air cells, to say that it  cannot give a passage to
such vapour.
   3dly, The  respiration of an air which has been charged
with the exhalations arising from oil of turpentine, com-
  * We know that fine injections pass from the branches of the pulmo-
nary artery into  the divisions of the bronchia; and that even water,
when pushed into the trachea, will return, at least a small quantity of
it, by the pulmonary veins and arteries.
  Bichat thought that the gases absorbed in the lungs must pass through
the mucous membrane; tut this is not the case unless  absorption lakes
place at the time they are in  the bronchia, for the mucous membrane
which lines the air-tubes does not extend into each bronchial lobule. 
ON  LIFE AND DEATH.
285
rnunicate a particular  smell to the urine.  It is thus that
this fluid is affected from the residence of the persons in
a newly varnished room.   In this  case  it  is evidently
by the  lungs  in  part, that the odoriferous fluid has  its
passage into the blood, and so on to the kidneys.  In fact,
I have often assured myself by breathing out of a  bottle
through a tube, air so charged (in which case it could not
act on the cutaneous surface) that the  smell of the urine
undergoes  a change.  If, then,  the  lungs will admit a
variety of substances, which do not enter into the compo-
sition of respirable air, for what  reason should they not
admit the  mephitic  vapour of mines  and  subterraneous
places.
   4thly, The respiration of humid air produces dropsy.
The  extent of the fact has been exaggerated, indeed, but
the fact itself is  true.  It proves,  that an  aqueous fluid
may  pass into the  blood, and  consequently that other
substances may pass into it also.
   5thly, If an animal be asphyxiated in sulphurated hydro-
genous gas, and a plate of metal  some time after its death
be placed under one of its muscles, the surface of the plate
contiguous to the  muscle, will be sensibly sulphurated.
The   foreign principle, then, which is here united with
the hydrogen,  must have been introduced into the circu-
latory torrent by the lungs, and have penetrated with  the
blood into  all the parts.  The  deputies of the Institute
have  observed  this phenomenon in  their experiments.  I
have  made a similar remark in asphyxiating animals with
nitrous gas.  A phenomenon of the same nature accompa-
nies  the exhibition of mercury.
   From the above, we have  nearly a right  to conclude,
that  the different deleterious substances of which the gases
are the vehicles,  do actually pass into  the  blood, and so
affect the organs.   Of this  matter,  however, I shall
■■uMtice  some further  proofs. 
286          PHYSIOLOGICAL RESEARCHES

  I have ascertained  by a number of experiments, that
atmospheric air, or any other aeriform fluid, may be made
to pass into the blood without alteration.
  Divide the trachea of a dog, inject the air-cells strongly
with common air, and continue to retain it in  the lungs.
The animal  will  immediately  discover  signs of great
distress and  agitation ; if an  artery now  be  opened, the
blood will be emitted in a frothy state.
  If hydrogen have  been employed, it  may easily  be
ascertained that the nature of the fluid is unchanged,  by
placing a candle over the bubbles which are disengaged.
  When the  blood for the space of thirty  seconds has
flowed in this state, the  animal life of the creature will
be finished, and death ensue, with all the symptoms which
accompany the insufflation of air into the black-blooded
system  of vessels.   The  re-admission  of air into the
lungs,  will have no effect in restoring the animal to life,
for  as soon as frothy blood can flow from any  one of the
arteries, it must already have affected the brain  with its
pernicious influence.
  In this case it may be perceived, that the causes of death
are  the same as those which proceed from  the insufflation
of air  into a vein.  In  the one instance the  air  passes
at once from the  lungs into the arterial system.   In  the
other,  from the veins  across the lungs and then into  the
arteries.
  When we  open the bodies of animals, which have been
killed  in these experiments,  the whole  apparatus of  the
red-blooded vascular system, is found to be filled with air
bubbles  of  various sizes.  In  some  circumstances,  the
blood wili be transmitted in the same state into the gene-
ral  capillary system, and from thence into the veins ; in
others it will be  stopped in  the capillary  system, and
in such cases, though the circulation may have continued 
ON LIFE  AND DEATH.
887
lor some time after the suspension of the animal  life, not
a single particle of air will be  discovered in the veins.
   In these experiments which I have frequently repeated,
I have never found that the least fissure has been made in
the bronchiae ;  nevertheless, I confess that it is difficult, to
say, whether  this  be so in their last  ramifications.   The
following phenomenon, however, may throw some light
upon  the subject; for as  often as air is pushed  into the
lungs vvith great  violence,  there will  be  produced  an
emphysema of the breast, or neck, from the  infiltration
of this fluid among the cellular texture, in addition  to its
passage into the blood.  But if the impulse  be moderate,
and the quantity  of air injected  not  much beyond  the
measure of a full  inspiration, it-will  pass into  the blood
only,  and not into the cellular  texture.*

  * This fact, frequently confirmed in my experiments, is not always the
same in man.  We often see emphysema  produced by  violent efforts of
respiration, efforts which have forced  into the cellular organ the air
contaiued  in the lungs.  Now,  if the  passage of the air in the  blood
preceded or even accompanied  its introduction into the neighbouring
cells of the bronchia, all these cases of emphysema would be necessarily
fatal, and even in.a sudden manner,  since,  from what has been said
before, the contact of the  air on the  brain, to which the circulation
would  carry it, would  inevitably interrupt the functions of this organ.
  Yet we see that emphysema is often cured, or does not produce death
for a length of time."|"   I saw, at the Hotel  Dieu, an air tumour, suddenly

  | I saw, in a little girl of seven or eight years of  age, an emphysema
which occurred in a paroxysm of coughing, and which extended to the
thorax, the abdomen and the superior part of the thighs; the swelling
of the  neck  was so considerable,  that at the moment 1 was called
suffocation was imminent.  I made, in  the skin above  the sternum, an
opening,  which very  quickly produced an evacuation of the air. In
five or six  days, though the hooping cough continued, this little patient
was  entirely cured  of the  emphysema,  which had  been  very  near
destroying her.  It did not appear to me that the lungs had participated
at all in the general emphysema. 
 i288           PHYSIOLOGICAL  RESEARCHES

   The experiments of which I have given the detail, ex-
 emplify phenomena which do  not indeed take place in the

 appear in the axilla, from the violent efforts of the patient to prevent
 respiration, whilst Desault reduced an old luxation.  In a few days this
 tumour disappeared without producing any inconvenience.   We find,
 in the  Memoirs of  the Academy of Surgery and in Treatises on Opera-
 tions, various examples of emphysema produced by powerful agitations
 of the  thorax, and  in consequence of the introduction of a foreign body
 into the wind-pipe; emphysema, with  which the patients have lived
 many day=, and from which even they have recovered.
  There is then no doubt, that often in  man  the  air passes from the
 lungs into the  cellular  texture, without entering  the  arterial system.
 My experiments on animals have not been exactly analogous to what
 happens  from the  introduction of a foreign body, when a part of the
 air enters and goes  out.   It is  then probable that from a cause precisely
 similar would arise  also  the same effect in  animals.
  And vice versa, the passage of the air in the blood-vessels sometimes
 takes place in man, without the infiltration of the cellular organ ; then
 the death is sudden.
  A fisherman, subject  to colick, was  suddenly  seized with it in his
 boat; the abdomen swelled,  the respiration became painful and  the
 patient died almost instantaneously.   Morgagni opened  the  body the
 next day, and found the vessels  full of air.  Pechlin  also says he  saw a
 man die  suddenly in great distress  and with a hurried  respiration, and
 he afterwards found a large quantity of air in the heart and in the large
 vessels.
  I have dissected  many bodies, in which, before  death there had been
 a sanguineous congestion in  the exterior  capillary system of  the face,
 the neck and even  of the thorax.  This system exhibited a remarkable
engorgement  and  lividity in all  its parts,  and I have found in opening
the arteries  and veins, in ihose of the neck and head especially, a
frothy blood,  mixed  with bubbles of air.  I learnt  that one of these
subjects  died suddenly  with  a convulsive affection of the  pectoral
muscles; I have no information respecting  the  others.  Besides, all
 who have had much to do with dissecting rooms, must have seen bodies
 of this  kind, which very soon  become putrid and emit an insupportable
 odour.   They have observed also that the air in the vessels existed
 previous  to the putrefaction.
  I suspect that in all these cases death has been produced by the
 sudden passage of air from the  lungs  into the blood, which has  after- 
ON LIFE AND DEATH.
289
ordinary process of inspiration, and therefore I allow that
no very rigorous induction can be drawn from them, with
respect to the passage of  deleterious  substances  into  the
mass of the blood ;  nevertheless it appears to  me, that
they very much confirm the probability  of such  fact,
which besides is demonstrated by many of  the preceding
remarks.  I shall conclude, then,  that such passage is real.
In fact, we  have seen 1st, That the  sole transmission of
the  black  blood  into  the arteries, will not.account for the
infinitely various phenomena  exemplified in the different
sorts of asphyxiae; 2dly,  That the simple contact of the
deleterious substance with the nerves of the lungs, can by
no  means be the cause of a death so rapid as that which
is occasioned  by these accidents ; 3dly, That, therefore,
we are  forced as it  were to suspect  the passage of the
poison  itself into the  blood ; 4thly, That a number of
considerations are in favour of such  suspicion,  and thus
that the fact is proved both directly and indirectly.*
  This  principle being   once established, a  variety of
results must  flow from it.  Of the first of these, of the
mode of action, namely, which the deleterious  substance

wards carried it to the brain ; nearly like what I have said takes place,
when, in a living animal, we force much air towards the lungs, and thus
drive this fluid into  the vascular system.
  By considering these phenomena in  connexion with the remarks
presented above on death from  the injection of air into the veins, the
opinion I have advanced,  will 1  think, be admitted, and it is  besides the
opinion of many  other physicians.  Many  experiments have already
been made  on the dead body relative  to  this point.  Morgagni  has
presented them in detail; but it is on the living that we must observe
the passage of the air into the blood in order to deduce consequences
which shall bear on the subject  on which we are treating.   We know
in fact what is the influence of death on the permeability of the parts.
                                         •
  * The above experiments explain the manner in which emphysema is
produced from any  very violent exertion of the muscles of the chest.
               37 
290          PHYSIOLOGICAL RESEARCHES
must  exercise  upon  the  different  organs,  I shall  say
nothing, having nothing to offer but conjecture.
  I shall accordingly content myself vvith inquiring what
system  it is which  is particularly influenced  by these
substances,  when  mingled  with the  blood.—Now,  1st,
This  system appears to  be the nervous one, and  that
portion  of it especially, which  presides over  the parts of
the animal life, the organic functions being only seconda-
rily affected ; 2dly, Of all the nervous system, the brain
is that part which is the most affected ; 3dly, Under this
relation  Monsieur Pinel appears to me to have been right,
in  placing some of the asphyxiae (those for instance which
are occasioned by the presence of a deleterious substance)
among  the  neuroses.   On this  head  the following  con-
siderations should leave us little doubt.
  1st, In all the asphyxiae, when the  presence of a dele-
terious substance cannot be doubled, the symptoms consist
of two general and opposite sets of phenomena, of spasm
and torpor.   Of two workmen  who had come up out of
the sewer  of the street  St. Andre  des  Ares, the one
sat  himself  down  upon a bulk, and fell into a  state of
asphyxia; the other vvith irregular convulsive  movements,
proceeded as far as the rue Battoir, and  then fell down
asphyxiated.  The  Sieur  Verville,  in  consequence of
inhaling the breath of a man who  was lying in a state
of asphyxia  from the vapour of lead, fell down suddenly,
and in a short  time became convulsed.   The vapour of
charcoal intoxicates, as it is  said.  I  have seen animals
asphyxiated with other gases, and  perishing with a  stiff-
ness,  such as could be produced only by the most violent
spasm.   The centre of all these symptoms, and the organ
from  which they emanate, undoubtedly is the brain, and
they depend upon its irritation  or compression. 
ON  LIFE AND DEATH.
291
  2dly, The animal life is always interrupted before the
organic life, wherever the asphyxiating cause has been of
a compound  nature.  Now the centre of the animal life
is the brain.
  3dly, I  have proved when the  animal perishes  from
the circulation  of the black blood in the arteries, that the
brain is especially  affected  even then ;  but in  the  same
way, that is, by the cephalic arteries, the deleterious sub-
stance itself, may be introduced into the brain.
  4thly, I have pushed a variety of deleterious  gases (for
example, sulphurated hydrogen) into the brain, and also
some of those substances which vitiate the nature of these
gases.  The animal has always perished with  symptoms
of spasm,  or torpor, and in  general the death which  is
occasioned by the different gases, is always similar to that
which is produced  by the introduction  of pernicious sub-
stances into the brain.
   5thly, The consequences of these asphyxiae,  when life
has  been  restored, invariably suppose  a  lesion  of the
cerebral system, such consequences consist of palsy, tre«
mour, wandering pains, and  derangements of the exterior
apparatus of the senses.
   From all these multiform  experiments and considera-
tions, we may surely conclude, that it is on the brain and
nervous system that the deleterious principle, introduced
into the blood, must act;  from the death of these  parts,
that of the others is derived.
   In this case  the  different  organs no  doubt are directly
enfeebled, and  may perhaps  be  immediately affected by
those principles, which flow into them together with the
blood, but all  such  phenomena, are even more visible in
the  animal, than in the organic life.
   Let  us  not  forget however, that a part at least of the
cause of this sort of death, consists in the influence of the 
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PHYSIOLOGICAL RESEARCHES
venous blood upon  the  organs, and  that  this  influence
must ever be in proportion to the length  of time that
such  blood continues to  circulate.  The differences then
which are found in the asphyxia?, may be said to proceed
from the  greater or less effect of the venous blood upon
the  system, from  the different nature  of the various
deleterious substances inspired, and  from  the age and
temperament of the individual affected.

II. In the greater number of diseases, death commences
                     in the lungs.

   I  have just spoken  of sudden  death.   I shall  now
enlarge a little on that which is the slow effect of disease.
Physicians must be well persuaded, that by far the greater
number of diseases, put an end  to life by an  affection of
the lungs.  Whatever be the  seat of the  principal affec-
tion, be it either an organic lesion, or a general disorder
of the  system,  the  action  of  the lungs in  the  latter
moments of existence, becomes embarrassed, the respira-
tion  difficult, and the oxydation of  the  blood, but slowly
effected; accordingly this fluid must pass into the arteries,
almost in  the venous  state.
   The organs therefore which are already enfeebled, must
be much more readily affected by the pernicious influence
of such blood, than those which are subject to  it, in the
different  cases of asphyxia.   In  this  way the loss  of
sensation, and  intellect,  are very  shortly  the effect of
embarrassment in the lungs;  and  ensue as soon  as the
brain begins to be penetrated  with  the fluid which is  so
transmitted to it.
   By degrees the heart and all the organs of the internal
life,  cease also  to  move.   It  is here  the black blood
which arrests these vital motions, which have already 
ON LIFE AND DEATH.
293
been enfeebled by the disease.  Such weakness, the con-
sequences of the  disease, is very rarely  the  immediate
cause of  death,  it only  prepares  it, by rendering the
organs more susceptible of  the alteration in the  healthy
state of tdie blood.  Such alteration is almost  always the
immediate cause of death.   The disease then, is  only an
indirect cause of death  in general,  it kills the lungs, and
the death of  the  lungs occasions  that of all  the  other
parts.
  From hence it may be easily conceived, why the small
quantity of blood contained in the  arterial system of the
subject, is almost always black.    For 1st, The  greater
number of deaths begin by the lungs.  2dly, We shall
see that those which have  their commencement in the
brain, are  equally the cause of this phenomenon.  Accord-
ingly there can  be only those, in which the heart ceases
suddenly  to act, after which the red  blood can be found
in the aortic ventricle, and  auricle.   Such appearance is
seldom found, excepting in the bodies of  persons who
have perished from extensive hemorhagy.
  From the frequency of deaths beginning vvith an embar-
rassment of the lungs, may  be conceived  also  the reason,
why this  organ is so frequently gorged with blood in the
carcase in general,  the longer  the  agony, the  heavier
and fuller are  the lungs.  When  such fulness is found,
together with  black  blood  in  the  red-blooded  system,
whatever  the disease may have been, it may be pronounc-
ed  that death has begun in the  lungs.  In  fact the con-
catenation of  the phenomena of death is from one of the
three organs,  from the lungs, brain, or heart, to all the
others.  Now when death begins in the heart, the pulmo-
nary vessels are generally empty, and there is red  blood
in the aortic system.  On the other  hand, if  death have
began in the brain, there is then indeed a certain quantity 
294         PHYSIOLOGICAL RESEARCHES
of blood in the arteries, but the lungs are empty, unless,
when gorged with blood,  by  some antecedent affection.
                   CHAPTER X.

OP THE INFLUENCE OP THE DEATH OP THE  BRAIN OVER
                THAT OP  THE LUNGS.

  As soon as the human brain ceases to act, the functions
of the lungs are suddenly interrupted ; this phenomenon,
which is constantly observed in the red  and  warm-blood-
ed animals, can happen only in  two ways.   1st,  Because
the  action of the  brain,  is directly  necessary to that of
the  lungs, or 2dly, Because the latter receives from the
former, an indirect influence by means of the  intercostal
muscles and diaphragm, an influence, which ceases with
the  activity of the cerebral mass.  Let us try  to determine
which of  these two modes is that of nature.

I. Is it directly that the  lungs cease  to act upon the
                 death of the  brain ?

  I shall  have proved that the death of  the  brain, is not
immediately  the  occasion of that  of the  lungs,  if I can
determine that  there is no immediate influence exercised
by the first, upon  the second of these organs, now, this
essential principle may be easily demonstrated  by experi-
ment.
  The brain can  exercise an  immediate influence on the
lungs, only by means of  the  par vagum  or the  great
sympathetic nerve, the  only nerves, which  according to
the  common opinion, establish  a communication between 
ON LIFE AND DEATH.
•295
the two organs (an  opinion however which is erroneous,
as the great sympathetic is only an agent of communica-
tion between  the organs and the ganglions of the system.)
Now 1st,  The influence which  is  derived by  the  lungs
from the  par vagum, is  not actually  necessary for  them
to act.  The  following experiments will show  the  truth
of this assertion,
   1st, Irritate  the par vagum  on one  or both  sides, and
the respiration of the animal will be somewhat quickened;
but  such  appearance is no  proof of an  immediate  influ-
ence, for any wound of the  neck, or any wound  whatever,
provided  that it be  the occasion of considerable  pain, will
be the cause of a similar phenomenon.
   2dly,  Cut  one of the  nerves, and the respiration will
be at once  affected, as when  the nerve is irritated ; but
as soon as the pain  ceases, the  embarrassment of the lungs
will disappear; and at the  end of four and  twenty hours,
the  phenomena of  life be concatenated with  their  accus-
tomed regularity.
   3dly, Divide these nerves on both  sides.  In this case
the  breathing will  be  much  more  precipitated, and will
not  return  to its ordinary state, as in the preceding experi-
ment; it continues laborious for four or five  days, and
the animal perishes.*

   *The division of the nerves of the eighth pair in the neck produces
two  kinds of  effects, which should be carefully distinguished ;  the one
relates to the larynx and the other to the lungs.  Among: the first,
aphonia is one of the  most striking symptoms.  We see a very good
reason for this phenomenon, when we recollect that the recurrent nerve
is a branch of the eighth pair ; but besides the loss of voice, the division
of the eighth pair often produces such an approximation of the ed^es of
the  glottis that the air cannot enter, and death  immediately  takes
place.
   Most usually, the approximation is not sufficient to prevent entirely
the entrance of the air into the  thorax ; but as the glottis has lost its 
296
PHYSIOLOGICAL RESEARCHES
   From  the two  latter  experiments  it  follows, that  the
 par  vagum  is  indeed  necessary  to  the  phenomena  of
 respiration, and that the  brain  must  exercise, of course,
 an influence over  this  function,  but at  the  same time, it
 may be seen, that without the immediate influence of  the
 motions in  relation with those of respiration, this function is always
 performed in a more or less incomplete manner.
   When these  observations were first made, it was hardly possible to
 give an  accurate explanation of them; but since I have ascertained the
 mariner  in which the recurrent and laryngeal nerves are distributed to
 the muscles of  the larynx, there  is  no  longer any difficulty.  By the
 division  of the  eighth  pair  at  the inferior part of the neck, the dilator
 muscles  of the  glottis  are paralyzed ; this opening does not enlarge at
 the moment of  inspiration,  whilst  the constrictors, which receive their
nerves from the  superior laryngeal, preserve their action entire, and shut
 more or  les^ completely the glottis.
  When the  division  of the eighth  pair does not close the glottis so
completely  as to produce  death immediately, another order of phe-
nomena  is developed.
  The respiration is at first embarrassed, and its rhythm often  experi-
ences a remarkable alteration; the inspiration is slow, and the expiration
quick and short.  The animal is averse to motion  and seems to be easily
fatigued. At  first the  formation of the arterial blood is not prevented,
but soon its vermilion  colour changes, it becomes darker and approxi-
mates more and more that of the venous blood.  The temperature falls,
and the  very embarrassed respiration  is only made by the aid of all the
muscular powers ;  the  coldness becomes evident, and  the  animal soon
dies.
  As this series of circumstances  is developing, the animals, on whom
the experiments are made, consume less oxygen, and form less carbonic
acid.
  We find, on opening the body, the  bronchia filled with a frothy,  and
sometimes a bloody fluid ; the lungs are engorged, and the  divisions of
the pulmonary artery are much distended with  very black blood.
  From  all that has now been stated, it is natural to conclude that, in
this last case, the  animals die because respiration can no longer be
effected, the lungs  being so altered  that the air cannot get into  the
bronchial cells.  To this cause should be added also the difficulty which
the blood experiences in passing  from the  ajrteries to the pulmonary
veins. 
ON LIFE  AND DEATH.
297
brain, the lungs will  continue in play, and consequently
that the interruption of such influence, as when the brain
is injured, will not be an immediate obstacle  to the con-
tinuation of the pulmonary actions.
  The question whether the functions of the lungs are
more immediately connected with  the  influence  derived
from the  ganglions,  may be decided by the following
facts.
  1st,  If on the one  and the other side of the neck, the
nervous thread be cut, which is usually regarded as the
trunk of the great sympathetic,  there follows  little or no
alteration in the phenomena of respiration.
  2dly, If the par vagum and  the great sympathetic be
divided at the same time on both sides of the neck, the
animal will die after a certain time, and much  in the same
way, as when only the par vagum is divided.
  3dly, When we divide the sympathetic nerve in the
neck, we  do not deprive the lungs of the  nerves which
come from the  first thoracic  ganglion ;  now these nerves
may contribute to keep up the action of the lungs, since,
as I  have said,  each ganglion is  a nervous centre, capable
of emitting its own peculiar irradiations, independently of
the  other centres, with which it communicates.
  But whether the  nerves, which are derived  from the
first thoracic  ganglion, do  really assist  the functions of
the  lungs, I have not  been able to ascertain by experi-
ments on the nerves themselves, for such  is the position
of the first  thoracic  ganglion in  most animals, that it
cannot be taken away without  doing so much  injury to
the  parts as would kill the creature, or throw  it into such
agitation, as wholly to confound the phenomena of which
we  are  in search, with those of a general distress  and
trouble.   From analogy, however, and from the destruc-
tion of other ganglions, by which the internal organs are 
298          PHYSIOLOGICAL RESEARCHES

supplied, we should  not have a right to suppose that the
lungs would cease to act, when the ganglion in question
is destroyed.
  Besides, the  following reasons  appear  to me to prove
unquestionably, the principle which I advance.  If great
lesions of the brain have the  effect of suddenly interrupt-
ing respiration, because this organ can no longer influence
the lungs by means of the nerves, which  come from the
first thoracic ganglion, it is evident that if all communica-
tion between the brain and this ganglion  be taken away,
such  influence must  cease, and respiration be suspended ;
but if we divide, as Cruikshanks has done, the spinal mar-
row on a level with  the last of the cervical vertebrae, the
animal will continue to live and  breathe for a length  of
time, notwithstanding the want of communication between
the  brain and  the lungs, by means  of  the first thoracic
ganglion.   From the above  experiments, we  may con-
clude, that  the  brain  does  not  exercise  any  direct and
actual  influence  over the lungs,  and  consequently that
other causes  must be sought  for, if we  mean  to account
for that sudden and  instantaneous cessation of the func-
tions of the latter of these  organs, when  those  of the
former are suspended.
  There exists, notwithstanding, a  phenomenon  which
seems to cast some  doubt upon  the conclusion which I
have deduced, and in the principle which it  establishes.
I speak of the sudden difficulty of respiration, and that
impeded circulation which are occasioned  by violent pain.
This distress appears to indicate  that the heart and  the
lungs are dependent immediately upon the brain ;  for the
distress is in the brain', say the greater number of authors,
and  the affection of the heart and lungs, a consequence of
the reaction of the brain ; but here let it be remembered,
that almost all pain  is made up, first  of sensation, and 
ON  LIFE AND DEATH.
299
secondly of some emotion, passion or affection.*   Now
as I have  proved  at  length, in  the  former part of this
work, all passion and  emotion have their seat in the inter-
nal viscera, and thus it will appear, that the trouble which
in such case is felt  in the heart and lungs, does not depend
upon the  brain for its cause, but is the immediate effect
of the passion, or emotion, which accompanies the sensa-
tion.  The following  considerations will  bear me out  in
this  conclusion.
   1st, In many instances the dyspnoea and  impeded circu-
lation, precede the pain.  Examine the thorax, and  place
your hand upon the heart of a man  about to undergo  an
operation,  and you will be easily convinced of this truth.
   2dly,  There is sometimes  a manifest disproportion be-
tween the sensation  of pain, and the distress  which is
experienced  about  the  heart, and in breathing.  I have
known the operation  of cutting away the  prepuce imme-
diately fatal.   Now in  this  case, it  surely could not  be
pain which killed the man.
   Sdly,  There are many persons who are  capable of sup-
porting violent pain,  with resolution.  Place  your  hand
upon the heart of such persons, and no agitation whatever
will  be felt there.   Nevertheless, their perception of pain
must be what  it is in  other persons.
   4thly, In  the course  of an  operation,  we are not  to
judge of the  patient's state  of mind, from  his  cries,  or
silence.  This sign is very deceitful; because a man  may
be sufficiently master of himself to  overpower the  influ-

  * These words passion,  emotion, affection, &c. have, I know, real
differences in the language of metaphysicians; but as the general effect
of the sensations which they  express is always the same on the organic
life ;  as this general effect is what alone concerns me, and as the
secondary phenomena are of no importance, I use these words indiffer-
ently for each other. 
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PHYSIOLOGICAL RESEARCHES
ence of his internal organs.  We must examine the heart
and  lungs ; their  functions, if  I  may  allow myself the
expression, are the thermometer of the  affections of the
mind.   It is not without reason, that the actor who plays
the part  of a courageous man, takes hold upon the hand
of him whom  he wishes to set at ease, and lays it on his
heart.  The exterior movements of the passions, are not a
fair criterion of the inward feelings of the individual, for
these movements may be feigned as well as real:  feigned
if they  originate in the brain : real if they have their
sources in the  heart ;—in the  first  case voluntary, in the
second involuntary.  Touch the pulse of the angry man,
if you wish  to know  whether he really  is  in anger.
When  I  see a  woman weeping or  convulsed at any dis-
tressing news, and  find  her pulse in its natural  state, I
know what to  judge of  her affliction.—On the  contrary,
if her grief be concentrated, but her heart beat strongly,
or her pulse have been  suddenly depressed, I know that
she feigns a calm which  she does  not  feel.  To judge
correctly, we must always compare the external move-
ment with the state of the  internal organs.  There could
be no deceit, were it possible to distinguish the involun-
tary movements produced  in  a  state of passion, by the
action of  the heart upon the brain, and then by the reac-
tion of the brain upon  the muscles, from  the voluntary
movements which are occasioned by the simple action of
the brain upon the locomotive system.
   However strong may be the  pain which has been  the
occasion  of the  dyspnoea, and  impeded circulation, of
which we have been speaking, this dyspnoea and distress
about the precordia, will cease, provided  only  that  the
pain be  continued.  Nevertheless, if the reaction of the
brain were  the real  cause  of the distress  in  question,
the contrary should  be  the case; for the continuation of 
ON LIFE AND DEATH.
301
the affection of the  brain, should  continue also to cause
its  re-action.  But  here the effect  of habit  is  evident,
though  the  pain  subsists ; the brain indeed  continues to
be affected, but the internal  organs cease  to  be so.   It
may be  easily perceived, that I am not here speaking of
those cases, where the action of  the  heart and lungs  has
been deeply troubled by the effect of pain.
  To the above considerations I might add many others.
vvith the view of proving,  1st, That although the brain
be the seat of the pain, it is not the source of those affec-
tions  of the  internal  organs, which are occasioned by
such pain ;  2dly,  That these affections depend  upon an
emotion, which is absolutely distinct  from  sensation of
whatever kind, both in its nature and effects.

II.  Is  it indirectly that the lungs cease to act upon the
                   death of the brain.

  Since the death of the lungs, upon the cessation of the
cerebral action, is not direct, there  must  exist  between
the brain and  the lungs, some intermediate  agents, the
cessation of whose functions, occasion the  cessation  of
those of the lungs.   These agents are the diaphragm, and
intercostal muscles ;  for  the}7 depend  immediately upon
the brain by means of the nerves, which they receive from
it, and consequently become paralytic on the death of the
brain ;  the following experiments are a proof of the fact.*
  *We  have said irua preceding note, that the  division of the nerves
of the eighth pair could produce death  in two ways; first, by closing
the glottis, and preventing the entrance of the  air into the air tubes ;
secondly, by altering  the lungs and preventing the production of the
chemical phenomena.  Of these two kinds of death the first is in some
measure accidental;  it is  an indirect effect of the interruption of the
action of the brain; but it is not so with the second, and though it may
not  be instantaneous, it is not less a direct effect of the  division.  It 
302           PHYSIOLOGICAL RESEARCHES
   1st, Cruikshanks divided the  spinal  marrow of a dog
between the last  cervical, and the  first  dorsal vertebras.
The  intercostal  muscles  accordingly were immediately
paralyzed, and the breathing of the animal  continued to
be  made by the diaphragm  only,  which  receives the
phrenic  nerve from a  point  above  the  section.   In this
experiment, it is easy to judge of the strong action of the
diaphragm, by that of  the abdominal muscles.
  2dly,  If  the  phrenic nerves  only be divided, the dia-
phragm becomes immoveable, and then  the respiration of
the animal is effected by the intercostal muscles only.
  3dly,  After the two preceding experiments, the animal
will live for a considerable time, but if the phrenic nerves,
and the  spinal marrow, towards the end of the neck, be
divided  at  the same time, or what comes to the  same
thing, if the spinal marrow be cut above the origin of the
phrenic nerves, then all communication between the brain
and  the  active agents of respiration  is cut off, and death
follows of course.
  4thly,  I have frequently observed, that half  an inch of
difference in the place where the spinal marrow is divided,
produces such a difference  in its consequences, that in the
one case the death is sudden, and supervenes in the other
only, after  an interval of fifteen or twenty  hours.  In
dissecting the carcases of animals killed in  this  manner,

might be supposed that the motions of the glottis being destroyed, and
the entrance of the air being rendered consequently more difficult, that
it is in consequence of this obstruction that respiration is embarrassed,
and that the alteration of the lungs is only a consecutive phenomenon.
But in the experiments made by M. Dupuy at Alfort, a free passage was
given to the air, by an opening  made in the trachea.  Now it cannot
be believed that the small wound necessary for this opening, could
contribute to produce the disturbance of the respiration, for a similar
operation,  is daily performed on horses, without producing the slightest
inconvenience. 
ON LIFE AND DEATH.
303
I have constantly observed that the difference  depended
always upon the circumstance, of the phrenic nerve being
cut or not.
   From  these experiments then it is evident, that respira-
tion ceases on a sudden, and in the  following manner, in
all lesions of that part of the  nervous system, which is
placed above the  origin of  the  phrenic  nerves.    1st,
There is an interruption of action in the voluntary nerves,
which are placed  below the point  of lesion, and conse-
quently in the  phrenic and intercostal nerves.   2dly, A
paralysis of almost all the muscles of the animal life, and
particularly of the diaphragm and  intercostal muscles.
3dly, A cessation of the mechanical phenomena of respi-
ration.   4thly, A suspension of the chemical phenomena
of respiration.   The interruption of all these movements,
is as rapid as their concatenation is prompt, in the natural
order.
   It is thus that those persons perish, who experience any
great lesion of the spinal marrow, between the brain and
the origin of the phrenic nerves.   Physicians  have  been
very much embarrassed, in fixing vvith precision the  spot,
when a wound of the medulla ceases to be  mortal ;  from
what I have advanced, the limit is easily assigned.* From
the same causes, concussion, and compression of the brain,
are also fatal.
   We should observe notwithstanding, that these different
causes of death, may act with various degrees of intensity.
If they act but feebly, they affect  the  intellectual  func-
tions only, for these functions are  always the  first to be
altered, in all lesions of the brain however small.  If the
lesion be greater, the affection extends to  the  muscles of
the limbs, and convulsion or palsy  ensue.   Lastly, if the
   * The experiments of Legalloi«  have clearly proved, that this point is
at the origin of the nerves of the eighth pair. 
 304          PHYSIOLOGICAL RESEARCHES

 lesion be  very great,  the  whole of the muscles of the
 animal  life,  the intercostals  and diaphragm, as well as
 the others, are paralyzed, and death follows.
   We now can reply  to the question  proposed at  the
 beginning  of this section, and affirm that the  death  of
 the lungs  is occasioned indirectly, by  the  death of  the
 brain.
   It  follows also, from the  principles which are above
 established,  that respiration is a  mixed  function, a func-
 tion placed as it were between the two lives, to which it
 serves as a point of contact, belonging to  the animal  life
 by its mechanical functions, and to the organic life, by its
 chemical functions ; and hence  we have the reason no
 doubt, why the existence of the lungs is as much connect-
 ed with that of  the brain, as  with that of the heart.
   It  may be observed  in  the series  of animals, that in
 proportion  as the organization of  the  brain is straitened,
 a number of the phenomena  of  respiration  also are lost.
 In birds, and the mammalia,  this function  as well as the
 brain, is much  more developed than it is in the classes of
 fish and reptiles.  It is known, that  the nervous system
 of those animals which breathe by tracheae, is less perfect
 than in  those which breathe by lungs ; and that in those,
where there is no nervous  system,  that  of respiration
 disappears  also.
   In  general, there is a reciprocal relation  between  the
 brain  and the lungs, especially in  birds and the mammalia.
The first of these occasions the action of the second, by
raising the  ribs and favouring the entrance of air into  the
bronchiae ;  the  second  also  keeps up  the  activity of the
first, by means of the red blood which it sends thither.
  It would be an interesting speculation  to  inquire  into
the relation of the  nervous system vvith that of respira-
 tion in  the class of insects,  for  as  they receive the  air 
ON LIFE AND DEATH.
305
by points, which open  externally, there seems to be no
mechanical action in the process of their breathing, and
thus the function appears with them to belong entirely to
the  organic life.
                   CHAPTER  XI.

 OF THE INFLUENCE  OF THE DEATH OF THE BRAIN OVER
                 THAT  OF THE HEART.

   In the preceding chapter we have shewn how the lungs
 remain inactive, when the brain ceases to act.—The same
 phenomenon, under  the same circumstances, takes place
 also in the heart, and must happen either immediately or
 mediately.

 I. Does the Heart cease to act  immediately in  conse-
   quence of the interruption  of  the cerebral action ?

   The greater  number of medical men, speak in much
 too  vague a manner of the  cerebral  influence.   They
 do not sufficiently determine  its  extent and limits, with
 respect to the different organs  of  the system.
   It is evident  that we shall have answered the question
proposed at the head of this section, if we can determine
what the influence of the brain is with  regard to. the heart.
Now, we  have  every reason to suppose,  that no  direct
influence  is exercised by  the  former over the latter of
these organs,  which, on the  contrary, is  immediately
dependent with regard to its operations, on the movement
communicated  to it by  the blood.  This assertion is by
no means a new one.  It has been admitted  by all  sound
             39 
306         PHYSIOLOGICAL RESEARCHES
physiologists;  but  as  many opinions in  medicine arc
founded upon a contrary principle, it will not be amiss to
dwell upon it a little.   It  is equally  demonstrated both
by  observation and  experiment—and  to begin with the
former :
  1st,  All violent irritation made upon  the brain, pro-
duces either partial, or general  convulsion in the muscles
of the animal life.   Examine  those of the organic  life,
on the contrary,  and little will be found  amiss in their
actions.
  2dly, All  compression of the  cerebral mass, whether
made by pus, water or blood, has ordinarily the effect of
paralyzing the voluntary muscles ; but  so long  as the
affection does not extend to the muscles of the breast, the
action of the heart is in no  degree diminished.
  3dly, Opium and wine, when taken in a certain quan-
tity, diminish the cerebral energy for the  moment and
render the brain unfit for the functions of the animal life.
The action of the heart, on the  contrary, is increased.
  4thly,  In palpitation, and the different irregular move-
ments of the heart, it is not observable that the principle
of these derangements exists in the brain.—In this respect.
as well  as on the subject  of syncope,  Cullen  has been
mistaken.  The  brain  during  such  time,  continues  in
action as usual.
  5thly, The numerous phenomena of apoplexy,  and
epilepsy, and concussion, &c. do certainly all of them tend
to shew, how independent the heart is of the brain.
  6thly, Every organ which is subject to the direct influ-
ence of the brain, is for that  very  reason an organ  of
volition.   Now, I should suppose, that few persons of the
present day, would be  inclined to  maintain with  Stahl,
that the  heart is among the  number  of such  organs.
What would life be,  were we able at will, to suspend tha 
ON LIFE AND DEATH.
307
action of the  organ, by which the  system  is animated?
From simple observation,  then, we  might conclude, that
it is not immediately that the heart ceases  to  act, when
the functions of the  brain are interrupted, but this funda-
mental  datum  of physiology and  pathology,  we shall
further establish,  upon actual experiment.
  1st, If the brain of an animal be exposed, and irritated
either with  mechanical or chemical  agents,  a  variety of
alterations will, indeed, be produced in the organs of the
animal life,  but none in the  heart, so long as the muscles
of the breast continue to perform their functions.
  2dly,  Experiments made  in the same manner upon the
spinal marrow of the neck,  present  the same results.
  3dly,  If the eighth  pair of  nerves  be  irritated, the
movements of the heart will not be accelerated ; they  will
not  be  arrested if  these  two  nerves be  divided.   In all
these experiments,  however, we must be careful to make
a proper distinction  between  the emotions  and passions
Qf the animal, and what it really suffers from the experi-
ment.
  4thly, The nature  of the great sympathetic nerve,  t
suppose to be known ;* now if  the  same  experiments be

  * Physiologists have paid much  attention  to the great sympathetic
nerve.  They have made, in relation to its uses, many conjectures but
few experiments ;  so that we have not on this subject  any very precise
notions.  The  deep  situation of the  ganglions renders  them almost
inaccessible, the superior  cervical  is almost the only one that can be
taken out without producing death.  M.  Dupuy, Professor of the
Veterinary School at  Alfort, has discovered  a method  by which he can
remove them with ease.   We shall now relate some of his observations.
  " 1st Experiment.  The first  experiment  was made on a young and
vigorous horse, who had been treated for the  glanders;  it soon appeared
that he was not affected with it, and that it  was merely the caries of a
tooth that had  led to  the belief of  the existence of the disease.
  " On the 24th of June his left guttural ganglion  was  extirpat-
«d.   Soon after the  operation, the eye of  that side appeared to be 
308           PHYSIOLOGICAL RESEARCHES
 made on the cardiac branches of this nerve, as were made
 upon the eighth pair,  the same results will follow.

 more sunk in  its socket, the eyelids were swelled and the pupil con-
 tracted.
  " On the 28th of June the  sublingual ganglion  appeared swollen,
 hard and attached; a discharge of fetid, greyish matter was discovered
 in the nostril of the same side.
  u On the 29th of June, the wound suppurated copiously.
  " From the 30th of June  till the 16th of July  the wound advanced
rapidly towards cicatrization.
  u From the 18th of July to the 15th of Augjust  the animal continued
 in the same state of health.
  "On the 15th  of August, the right guttural ganglion with a portion of
 the nerve was removed; this  operation was followed by the same
 phenomena as the preceding, with  this difference, that  two days after
 the animal  could not swallow water, it  run out at the nostrils.  There
 was in fact a communication between the  nostrils and mouth from  the
 carie« of  the  back molar tooth, the roots of which were opposite the
 maxillary sinus, that had an opening into  the nostril;  the voice was lost.
  "On the 20th of August, he  was much emaciated, with the skin  dry
 and adherent; the cheeks,  below  the jaw, were  constantly moistened
 with sweat, which had  been observed for twelve or  fifteen days.  The
 wound of the right side remained fistulous;  the skin was covered with
 scurf, the sheath and scrotum, as well as the hind legs, were oedematous ;
 the animal  died.   Nothing  remarkable was  discovered  on  dissection.
 Below the sub-occipital foramen  the  great sympathetic was slightly
 swelled, in the form of a knot, in the place where  the division had been
 made."
  " 9d Experiment.  On the 26th  of April, the right guttural ganglion,
 with a portion of the nerve, was removed from a sound horse, four and
 a half years old,  strong and in good condition.  The  ganglion of the
left side was first a little mutilated, and  the  nerve was removed poste-
riorly to the extent of  thirty three  centimetres.  The  animal did  not
 manifest so much pain as might have been expected.
  " The  conjunctiva soon  became red and  the eyelids partly covered
 the eyes; the respiration became painful and loud ; the  pulse was hard,
 strong and frequent.  The  animal refused  all food, and  drank with
 great  difficulty.
  "This  state continued till  the  10th of May  following.  The two
 wounds were almost healed  ; the  animal eat and  drank well ; but the 
ON LIFE  AND DEATH.
309
   I do not offer in detail the whole of these experiments;
the greater part of them are well known :  I was induced
to repeat them, as authors are not agreed upon their con-
sequences.
   The experiments of galvanism, are well  calculated to
throw light upon  the relations existing between the heart
and the brain ; these  I  have taken  care  to repeat  with
the  utmost exactness,  and  whatever authors may  have
advanced, they are all in favour of the  above opinions—
for 1st, If the galvanic apparatus be applied to the brain,
and to the heart, and inferior extremities of a frog, and
the communication  made  between the  metals,  there will
constantly be seen a strong  contraction  in  the muscles of
the limb,  and little or none  in the  heart.   The same will
be the case, to whatever  voluntary  muscle the  zinc  be

hind  legs and scrotum were still so much swollen  as to interfere with
his walking; the conjunctiva remained  red and the pupil contracted.
   " Towards the  13th of May the skin became  adherent a*id covered
with scurf;  the cutaneous respiration was nearly destroyed.
   "On the  25th  of May, the swelling of the legs and the scrotum
became considerable, notwithstanding the frictions with  water  and
turpentine, which were made  several times a day since the 13th ; he
could, with  difficulty be got out of the stable to be examined.   The
pulse retained its hardness and frequency.  The dung was hard, black
and small.
   " During the month of June the phenomena were  similar to those we
have enumerated ; the swelling of the scrotum and the legs resisted the
tonic and stimulating applications.
   On examining the body, the ends of  the nerves that had been drawn
out were found swollen as in the first horse.   Similar results have been
obtained  in all the other experiments that  have been made on this
subject.  It  may be said  in conclusion,  that the  phenomena which
appear after the removal of this ganglion, and which do not depend on
the operation, are the contraction  of the *puP''i  the redness  of the
conjunctiva, general emaciation, accompanied with swelling of the legs,
and a  scurfy eruption which ultimately affects  the whole  cutaneous
surface. 
310          PHYSIOLOGICAL RESEARCHES
 applied.   2dly,  The same results will be  had,  on  the
 communication  being  made between the metals applied
 on the one  hand to the spinal  marrow above the giving
 off of the sympathetic, and on the other hand to the heart,
 and any  of the voluntary  muscles.
   3dly,  On establishing  a  communication  between  the
 metals applied to the cardiac nerves, and to the heart of
 the animal, there has been no  contraction  in the heart.
 In  all  these essays,  the natural disposition  between  the
 parts which serve to unite the two  organs, is.preserved :
 there are other  experiments which  consist  in  detaching
 the heart from the breast.  2dly, In placing two points of
 its surface in contact  with  two different  metals.   3dly,  In
 making the communication between them with a third.
 From thise xperiment, Humboldt and other  philosophers
 have procured contractions, but I  have taken  care  to
repeat  it vvith the  greatest accuracy,  and  must  assert,
that I have  seen little or nothing of the kind ;  indeed,
if I had,  I  should have concluded  nothing  from  it;
for it  appears  to me, that to decide upon the influence
of  the brain  over the heart,  a portion at  least  of  the
 nervous  system, should  be in  contact with one of  the
metals.
  I shall now pass to my  experiments on red and warm-
blooded animals.  They are necessary  for the decision of
the question before us, as the  mode of contractility  in
these  animals  differs much from that of the  animals sub-
mitted  to the experiments already mentioned.
  1st,  In the winter of-the  year 1798,  I was authorzied
to make  different essays  on the bodies of  persons who
 had been guillotined.  I had them at my disposal thirty
or forty minutes after they  had undergone the punishment.
 In some  of them, all mobility was extinct; in others,
 Jhis property could be reanimated  in all  the muscles by 
ON LIFE AND DEATH.
311
the  common  agents, and in  those of the animal life,  by
galvanism especially.*   Notwithstanding which, I  could
never occasion the least motion, in applying the apparatus


  * Galvanic experiments  have at  different times  been made  on  the
bodies  of those who have been  executed.   Vassali, Julio and Rossi
made a great number of them at Turin;  but the piles  that were then
used were very weak compared with.those that are  now employed.   In
the experiments made at Newgate on the body of a criminal, the limbs
were violently agitated, the eyes  opened  and shut, the mouth and the
jaws moved in every direction, and  the face  was  thrown into the most
frightful  convulsions.  The last and most complete  experiment?,  that
we know of, were made  at Glasgow in November 1818  by Dr. Andrew
Ure.  He used for these experiments a battery composed of two hundred
and seventy pair of plates four inches square, with communicating wires,
and so arranged that they could be insulated  fop the purpose of applying
the electricity in a more convenient manner.
   The subject, on whom these experiments were made, was of middle
heighth,  about thirty years of age and of an athletic  constitution.   He
was on the gallows almost an hour, and he was  not  convulsed after
being hung, whilst a robber  executed  at  the same time  was violently
agitated  for a considerable time.  He was  carried to  the anatomical
theatre of the university, about ten minutes after he was removed  from
the gallows.  His face had a perfectly natural appearance being neither
livid nor swollen, and the neck was not dislocated.
   About five minutes before  the arrival of  the police  officers with the
body, the battery was charged with diluted nitro-sulphuric acid, which
quirkly put it in a state  to exert  an intense  action.
   1st Experiment.  A large  incision was  made immediately below the
occiput.   The posterior half of the first vertebra was then removed and
the spinal  marrow laid  bare, at  the same time a considerable  incision
was made  in the great  glutasus  muscle, in order to  expose the sciatic
nerve.   A  slight incision was made  in the  heel; no blood escaped  from
any part.   A wire  which  communicated  with  one  extremity of the
battery was put  in contact withrtlie spinal marrow, whilst  the other was
applied to  the sciatic nerve.  All the  muscles of the body were in an
instant agitated with convulsive motions  which  resembled a violent
shuddering.  The strongest convulsions were on the left side;  at each
time of renewing the electric contact by moving the second wire  from
 >.he haunch to the  heel the kner  being  previously  bent, the.  leg wis 
312
PHYSIOLOGICAL RESEARCHES
either  to  the  spinal  marrow  and  the heart, or to  this
latter organ  and  the  nerves, which it receives from the

thrown out with so much force, that it threw down one of the assistants
who in vain endeavoured to prevent the extension.
  2d Experiment.  The left phrenic nerve was laid bare towards the
external edge of the sterno-thyroideus muscle, three or four inches above
the clavicle; as this nerve  goes to the diaphragm, and  as it communi-
cates with the heart by the eighth pair, it was expected, that by throw-
ing the galvanic  fluid through it, the  action of respiration would  be
renewed.   In consequence  a small incision  having  been made  under
the cartilage of the seventh rib, the point of  an insulated  wire was
placed in contact  with  the diaphragm, whilst the other was applied to
the phrenic nerve of the  neck.   This muscle, the  principal agent of
respiration,  contracted  immediately,  but  with  less force  than was
expected.   As I knew by numerous experiments that we could produce
the most powerful effects from the galvanic  fluid, by leaving the extreme
communicating  wires  perfectly in contact  with the  parts on which we
wished to operate,  whilst, in  order to complete the  electric  chain,
we carried the  end of the wires  the length of  the plates, into the last
trough of one of the poles and  immediately plunaed  the other wire into
the last cell of the opposite side, I had recourse to this measure vvithout
loss of time.  The success  was  truly astonishing ; instantly commenced
a  strong and  laborious respiration.  The  chest  rose  and 'fell; the
abdomen was pushed  forward  and then flattened, and the diaphragm
contracted and  relaxed.  All these motions appeared without interrup-
tion as long as I continued the  electric excitement.
  In the opinion of many scientific persons who were witnesses of this
scene, this  experiment was  perhaps  the most striking that had ever
been made with an electrical apparatus   It should be recollected that
during half an  hour at least,  before this, the body had  been  nearly
exhausted of blood and the spinal  marrow  had  been  much lacerated.
   No pulsation  could be perceived either in the heart or at the wrist.
   3d Experiment.  The suborbitar nerve wa<= laid  bare  at its exit from
the suborbitar foramen.  One of the conducting wires  was applied to
the nerve  and the  other to the heel; the most extraordinary grimaces
were produced.  All the muscles were put simultaneously  in action in
a frightful manner; rage, horrour, despair,  anguish and  frightful  smiles
united their hideous  expression  in the!  face  of the assassin.  At the
sight  of this, many of  the spectators were obliged to leave the  room
and one of them fainted.
   4th Experiment.  The last galvanic experiment was made by trans- 
ON  LIFE AND DEATH.
313
ganglions of the sympathetic, or the par vagum.   Never-
theless,  the common mechanical  excitant,  immediately
applied to  the  fleshy  fibre, occasioned  its contraction.
Could this have happened in consequence of the separation
of the nervous fillets  from  the brain ?  assuredly not;
because  the voluntary  muscles were  equally  separated
from  it, and yet affected strongly.   If any  doubt remain,
the following  experiments will clear it up.
  2dly,  In dogs and guinea pigs, I  have repeatedly appli-
ed the metals, first to the  brain and the heart, then to the
trunk of the spinal marrow, and the heart; then to the par
vagum and the heart.  The communication being made,
was followed  by no apparent result.
  3dly,  On  making  the communication  between  the
metals, when  applied to the cardiac nerves  and  the heart,
there was  no  very sensible motion.
  4thly, Humboldt has asserted, that when the heart is
speedily detached with some of its nervous threads about
it,  a  contraction  may  be  excited,  by arming the  nerves
vvith  a metal, and then by touching this metal with another.
I have many times tried this experiment  in vain.  I con-
fess,  however, that once it appeared to me  to succeed.
  5thly,  On the contrary, I have almost  always succeed-
ed  in producing  contractions in   the heart, by  cutting
it away  from  the breast,  and making a communication
between a couple of metals, applied to different points of

mitting the electric fluid from the spinal marrow to the cubital nerve near
the  elbow ;  the fingers moved quickly like those  of a performer on a
violin; one of the assistants who endeavoured to keep the hand shut,
found  that it opened in spite of his efforts.  A wire was applied to a slight
incision made at the end of the first finger ; the hand had been previously
shut;  the finger was instantly extended, and, after a convulsive agitation
of the arm,  the  dead man seemed to point  his finger at the spectator?,
some of whom thought that he had come to life.
  An  hour was consumed in these experiments.
               40 
314
PHYSIOLOGICAL RESEARCHES
its surface.  This, if I am not mistaken, is the only means
of evidently producing the phenomena of galvanism in
this organ, but with respect to  our present question, the
experiment is wholly inconclusive.
  All these experiments I have repeated many times, and
with the  most scrupulous  precautions, nevertheless I do
not pretend to call in question the reality of those results,
which other physicians have remarked.   It is well known
how very variable those experiments are, which have the
vital powers for their object.  Besides, in admitting even
these different results, I  do not see how it is possible to
refuse acknowledging, that with  respect to the stimulus
of galvanism,  there  is a  wide  difference between the
susceptibility of the muscles of the animal life, and those
of the  organic life.  Again, supposing  that the galvanic
phenomena were the same in both sorts of muscles, the
fact would prove nothing more, than that these phenomena
with regard to their succession, follow laws directly the
contrary of those, which are displayed in the phenomena
which take place, when  any common cause of irritation
is applied  to the nerves and their corresponding muscles.
  The proofs adduced, will allow us to conclude, that the
brain exercises  no direct  influence over the heart, and
consequently,  that when  it ceases to act, the functions of
the latter  must be interrupted indirectly.

II. In case of lesion of the brain, is  the death of the
 heart occasioned by that of any intermediate organ?

  When the brain dies,  the  heart dies, but not directly.
There must be some  intermediate  organ  then, the death
of which occasions that of the heart.*   That intermediate
  ♦It is shewn by the  beautiful experiments of M. Legallois, that the
heart  derives the principle of its forces from the spinal  marrow, and 
ON LIFE AND DEATH.
315
©rgan is the lungs.  In this sort of death, the  following
is the series of the phenomena which may be observed.
   1st,  The  cerebral  action  is  interrupted.   2dly, The
action of all the  muscles of the  animal  life, and conse-
quently of  the intereostals  and diaphragm, is annihilated.
3dly, The  mechanical functions of the lungs are suspend-
ed.   4thly, The  like ensues with respect to their chemical
functions.   5thly,  The fibres of the heart are penetrated
with black  blood.   6thly,  The fibres when so penetrated,
die.
   Such sort of death then, has much resemblance with that
which is occasioned by the  different asphyxiae.   It is only
more sudden,  and that for reasons which I shall presently
point out.   The following experiments  are an evident

from the whole spinal marrow, since the destruction of one of its three
portions can arrest completely the circulation.  The destruction of the
spinal marrow does not entirely annihilate  Ihe motions of the  heart;
but it weakens them sufficiently to prevent the circulation, and  this
weakening is so  much  the greater, as  the portion of spinal  marrow
destroyed is larger.  It may be presumed from this, that notwithstand-
ing the weakening which follows  the removal of a part of this marrow,
the circulation may still continue if we lessen  the  sum of the forces
which the heart must expend to  maintain it.  For this it is only neces-
sary to diminish by ligatures on the arteries, the extent of the circle to
which the heart distributes the blood.  This conjecture is confirmed by
experiment.  It has been seen, for example, that the destruction of the
marrow which is  very suddenly fatal in full grown  rabbits, ceases to be
so, if before doing it the abdominal aorta is tied  between the coeliac
and  the superior mesentric arteries.   The application of the same
principle to other parts of the body leads to  a still more surprising result,
it is  this, that in order  te support life in rabbits of a certain age, after
having destroyed the cervical marrow, it is necessary first to cut off the
head.  They  will be completely dead if the  marrow be destroyed before
they are decapitated ;  this arises from the fact, that by cutting off  the
head all  this  part is taken out  of the  domain of the circulation, and
that by it the heart having need of less force to continue its function,
we can weaken  it by the  destruction  of the cervical  marrow without
its ceasing to perform it. 
316          PHYSIOLOGICAL RESEARCHES
proof that the phenomena take place as I have described
them to do.
   1st, I have always found black blood in the red-blooded
system  of all animals, killed by concussion or compression
of the brain ; the heart livid, and  the  different surfaces
coloured as in asphyxia.
   2dly,  I opened  the  carotid  artery of a dog ; the red
blood instantly gushed out, but was immediately suppress-
ed, and  the artery tied.  I  then killed the  creature, by
striking him with violence  on the occipital bone.*   The
animal  life, and consequently both the mechanical and
chemical functions of the lungs, were suddenly suppressed.
The artery was then united.   It poured  forth the black
blood with a feeble jet, for some little time, and  after some
minutes, the heart entirely  ceased to move.
   3dly,  I have always obtained a similar result in open-
ing the arteries of different animals  which I afterwards
killed, either by dividing  the marrow between the  first
vertebra and  occiput,  or by strongly  compressing the
brain, which I had previously  exposed.—It is thus  also
that animals perish, by the carotids of which a deleterious
substance has  been injected.
  4thly, The preceding experiments explain the reason
why the blood is  black which  flows from  the arteries of
animals, which  are bled in  our slaughter-houses,  after
having been knocked in the head.   If the blow has been
violent, the blood  issues such as it was in the  veins, but
if the action of the diaphragm and intercostals  has only
been weakened  by the  blow, the redness of the blood is
only diminished.

  * When an animal is thus struck, it is not certain that the concussion
has not extended its effects  upon a greater  or less part of the spinal
marrow ;  and it is not known consequently if the motions of the heart
would not cease, even when asphyxia might be prevented  by means of
artificial respiration. 
ON LIFE AND DEATH.
317
  The state in which the respiration may be (and it is
altered from  a variety of circumstances during profuse
hemorrhagy) occasions a great variety in the colour of the
arterial blood :  hence we have the reason why it is found
of so many different shades in the great  operations of
surgery.   At  the beginning of these, it often flows out
quite red ;  at the end of them, is sometimes almost black.
The easy or  embarrassed state of the respiration  of the
patient, is  the  occasion  of these  varieties.   This I have
frequently remarked, when attending Desault,  and was
often struck with the appearance,  before I knew the cause
of it.
  I have never found any relation whatever, between the
obscure colour of the blood, and the  compression exercis-
ed above the artery, as some have asserted to take place.
There is, indeed,  a connection between the  colour and
the impetuosity of the jet, but the reason of this is evident
to any one who has read the foregoing pages.
  To return  to the point of doctrine on which we are at
present occupied, I am persuaded from the considerations
and experiments which  are  adduced in the course of this
chapter, that  the manner in which the heart ceases to act,
when the cerebral  functions are suspended, can no longer
admit of a doubt, and that we may resolve the question
proposed, in affirming that under such circumstances, the
death of the  heart  is occasioned  through  the  medium of
that of the lungs.
  There is this difference, then, between the death of the
heart, in consequence of that of  the brain, and the death
of the brain in consequence of that of the heart, that the
one is indirect, the  other direct, as we have already seen.
If some  men, as Stahl  asserts, have really been able  to
suspend  the  movements of the  heart, the  fact is  not  a
proof of the influence of the mind over the muscles of the 
318           PHYSIOLOGICAL RESEARCHES
organic life,  but of its  power  over the mechanical, and
consequently, the chemical phenomena of respiration.
  In red and cold-blooded animals, the death of the heart
does not succeed  the  death  of  the brain so quickly as it
does in red and warm-blooded animals.   Cut off the head
of a frog, and the heart will continue to beat for some time
afterwards.   This  phenomenon  will be  easily accounted
for,  if we  recollect  that  respiration with these  animals
may be suspended a length of time, without arresting the
movements of the heart.
  In fact, as the heart dies only because the  lungs die in
the first place, when the cerebral functions are interrupted,
it is  plain that there  ought to  exist between the violent
death of the heart and that of the brain, an interval nearly
equal to that during which, in the natural state, there may
be a suspension of respiration.
                  CHAPTER XII.

OF THE INFLUENCE OF  THE  DEATH OF THE  BRAIN OVER
             THAT OF  ALL  THE ORGANS.

  When  the  brain dies, the  animal life dies, for  the
functions of this  life, either  directly or indirectly, have
their seat in the brain.  It is manifest, that all  the opera-
tions and affections of the mind, together with sensation,
locomotion, and the voice, must be put an end to in such
case.   The  difficulty  then respects the functions of the
organic life. 
ON  LIFE AND DEATH.
319
I.  Is the interruption of the functions of the organic
   life  a direct  consequence of the cessation of the
   cerebral actions ?

   We shall here adduce both observation and experiment
to prove, that the internal functions are all of them, as well
as the action of the heart, withdrawn from the immediate
influence of the brain.
   1st,  There are a number of diseases affecting the  brain,
wrhich occasion so general  a suspension of the animal life,
as to leave  neither sensation nor voluntary motion, except-
ing some feeble  oscillations of the intercostals  and the
diaphragm.  In this state the individual has lost the half
of his existence, but the one half composed of the organic
functions, continues in the meanwhile to subsist, and in
many cases with energy.   This phenomenon is exempli-
fied continually  in apoplexy, in concussion of the  brain,
and extravasation of blood upon its surface.
   2dly, During  sleep the secretions  certainly go on,
though  Bordeu  insists upon  the contrary opinion, vvith
the view of proving the influence of the nerves over the
"•lands.   During a state of sleep,  digestion goes  on as
usually  it does.   The  exhalations of the  body are made
with perfect freedom, and  often augmented beyond their
natural  quantity  ; the process of nutrition continues to
be effected, and  is probably under such  circumstances,
increased.  There are many proofs in favor of this opin-
ion ; but a state of sleep is a state of collapse in the brain.
Then, neither is the relaxation  of the functions of the
internal organs the consequence of a relaxation of  action
in the brain, nor the death of the former the immediate
effect of the death of the latter. 
320
PHYSIOLOGICAL RESEARCHES
   3dly, The sleep of animals, which  pass a certain part
of the year in a state of torpor, is a very strong proof of
the co-existence of a suspension of the cerebral functions,
with a  permanent action of those of the organic life.*
   4thly,  In the  different  palsies ; in  those for instance
which affect the lower limbs, and the viscera of the pelvis,
in consequence of some concussion or  compression of the
medulla spinalis,  the communication  of the  paralyzed
parts with  the brain, is either entirely cut off, or only
enfeebled.  It is entirely interrupted when  all feeling and
power of moving have ceased—it is enfeebled, when the
one and the other of  these properties are only enfeebled.
But  in these two cases the general  and  the capillary circu-
lations  continue.  The exhalations from the  cutaneous
surface  and in the cellular substance, are made as usual;
the process of absorption goes on,  for without absorption,
we  should soon see  dropsy.  The secretions  also are
effected, for nothing in such sort of palsy is more common
than a copious secretion of mucus from the bladder.  As
for nutrition if it be diminished in energy, the process is
certainly  never entirely arrested.
   5thly,  Spasms and convulsions,  which proceed from an
unnatural  energy of the cerebral  action, have little influ-
ence  over the exhalation,  secretion, and  nutrition of the

  * When two states, which are not perfectly similar, are designated
by a common name, it is very difficult, whatever care may be  taken to
distinguish  them,  not  fo  apply to  one  something which exclusively
belongs to the other.  This is perhaps one of the most frequent sources
of our errours.  In this case, for example, it does not seem that  there
is a great inconvenience in designating by the word sleep the state of
torpor of certain  animals during a part of the year.  It is well known
that we understand by it  altogether a different thing from the sleep,
which in  warmer seasons of the year, comes on periodically every day ;
yet in consequence of the identity of the name, we are disposed to
admit identity of character and to infer from one respecting the other. 
ON  LIFE AND DEATH.
321
parts in which they make their appearance.   The trouble
and  excessive  agitation of  the animal  life of such  parts,
compared with the calm of their organic life, are tacts
well worthy of remark.
  6thly, Foetuses without heads, in the uterus, possess as
active an organic life, as those which have no defect of con-
formation whatever, and sometimes at  the time of  birth,
are  monstrous even in bulk; this circumstance I  have
frequently had occasion to  observe at my amphitheatre ;
the functions of  nutrition then  and circulation  may take
place vvith  activity,  though deprived of the influence of
the brain :
  7thly, In animals, which have no cerebral mass, and in
those (the polypes  for instance) where not even a nervous
system  is apparent, these organic processes are admirably
well  conducted,*  the  greater  part of them indeed are
common to the vegetable, and the animal.
  8thly, If the different proofs, which Bordeu has given
of the influence of the brain over the  functions be well
examined, it will seem that no  one of them is decisive.
The sudden interruption of the secreted  fluid, in conse-
quence  of  the  division  of the nerves of the part, would
be the only proof  which I  should be inclined to  admit as
positive.   Now I  am not  acquainted with  any means of
making  such division  with exactness.  We have  heard
much of an experiment of this nature  upon  the parotids;
but  the disposition  of the nerves distributed  to  these
o-lands  is such,  that 1  have not  been even tempted to

  * What is the circulation  of an animal which exhibits no trace of
vessels ? what inferences can be drawn for man  from the mode of nutri-
tion of a polypus? what relation can be established between the com-
plex function which presides in the mammalia over the support of the
organs, and the kind of imbibition by means of  which the zoophyte  is
developed and preserved ?
              41 
'S22          PHYSIOLOGICAL RESEARCHES

repeat the experiment.  The testicle is better adapted  for
the attempt, and accordingly vvithout touching the vessels,
I divided the spermatic nerves, but an inflammation and a
deposit of matter took place in the gland, and with respect
to the secretion of the semen, I could not judge of  the
effect of the division of the nerves.  But  here this very
inflammation coming  on  vvithout  the influence of  the
brain, appears to mc to infer a possibility  of the seminal
secretion  under the same circumstances.   In this experi-
ment, the spermatic artery cannot be separated  from  the
plexus which it receives  from the great sympathetic, so
intricate  is  the network  of these nerves  about it;  their
division  however is  of little  consequence, as they  come
from  the ganglions.   It is easy to break off all communi-
cation with  the brain, by destroying the lumbar fillets of
nerves.
   I might add a number of other considerations to  the
above, but here I have to remark that the distinction of
the sensibility and  contractility  into their two kinds is
particularly  worth attention.   In fact, the idea of sensi-
bility in our usual way of seeing things, suggests the idea
of the nerves, the nerves again make us think  upon the
brain, we associate  the  three  ideas, but  excepting  for
the animal  life they  should not  be associated.  In  the
organic life, at least their union is not  immediate.
   I do not mean to say that the  cerebral  nerves have no
influence  whatever  over the  organic  sensibility,  but  I
maintain that  such influence is not direct  and not of the
nature of that  which is observed  in the animal sensibility.
   Many authors have  already  discovered a  number of
difficulties resulting  from the opinion which makes the
nerves the exclusive  seat of sensibility, they have even
sought for other means of explaining the phenomena of
great living bodies.   But of its agents  we  know as little 
ON  LIFE AND DEATH.
323
as we do of its nature, and have no means of elucidating
questions of this  sort.  Let us be contented with analyz-
ing, collecting and comparing  facts with  seizing their
general results ;  the aggregate  of these  researches will
compose the  true theory of  the vital powers ; the rest is
only conjecture : but  besides the considerations which I
have offered,  there is  another which  manifestly goes to
prove that the organic functions are not under the imme-
diate influence of the  brain, and this is, that  the viscera,
which  perform such functions do not receive their nerves
from the brain but from the ganglions.
   This anatomical fact is  observable  in  the liver,  the
kidney, the  spleen, pancreas,  intestines, &c.  even  in the
organs of the animal  life  there are nerves which serve
for the external,  and nerves which  serve for the internal
functions.  In such the former come directly  from the
brain,  the latter  from the  ganglions.   Thus the ciliary
nerves, which come off from the opthalmic ganglion, are
those which  preside over  the secretions  and nutrition of
the eyes, the optic nerve which is derived from the brain
is the  nerve of vision.*   In the same way the olfactory
nerves of the pituitary membrane are the agents by which
we have the  perception of odours, the threads which come
off from the ganglions of Mekel, relate only to the organic
phenomena of the membranes.
   Now the nerves of the ganglions cannot transmit the
action of the brain ; for we have  seen that the nervous
system derived from these bodies should be considered as
entirely independent of the nervous system  of the  brain ;
and that the  great  sympathetic does not derive its origin
   * The external ciliary nerves  only come from  a ganglion.  The
internal ciliary  ones which have  precisely the same  distribution and
serve also very probably the same uses, come  from a cerehral nerve,
from the nasal branch of the ophthalmic-. 
 324          PHYSIOLOGICAL  RESEARCHES

 from the brain,  from  the  spinal marrow,  or  from the
 nerves of the animal life; but  from  the  ganglions exclu-
 sively ; this nerve  indeed  does not exist, it is only the
 aggregate of so many small nervous  systems as there are
 ganglions, which  are the particular centres of the organic
 life, just in  the same way as the brain  is the  great and
 only centre of the animal life.
   To establish it  as a fact that, the great sympathetic such
 as it is understood does  not in reality exist, I might add a
 number of proofs to  those, which I have already mention-
 ed.  The nervous communications,  which are taken for
 it, are nothing more than accessories to the system of the
 ganglions;  for 1st,  These  nervous   communications, as
 Cuvier  has  observed, are. not met with in  the necks of
 birds;  between  the upper  cervical  and first thoracic
 ganglion there is  no vestige of  a sympathetic.   In  birds
 then, the upper cervical  ganglion is that which  in man
 the opthalmic ganglion, the ganglion of Mekel and others
 are.   This disposition, which is  natural  in birds, agrees
 with what I have sometimes observed in the human sub-
ject between the first lumbar and the last thoracic ganglions,
 as well as between the lumbar and sacral ganglions them-
 selves.  2dly,  In  m;tny instances there  are  no ganglions
 in the spot where the pretended sympathetic nerve  com-
 municates with the spinal marrow.   This may be seen in
 the  human  neck, and in the abdomen of fish, but  such
 disposition should be thus regarded.   The inferior cervi-
 cal ganglion furnishes a great  branch which ascends to
 the superior cervical ganglion, and   establishes between
 the two a direct communication ; but in ascending it dis-
 tributes  many branches to  each of  the  cervical nerves,
 which form  a  secondary communication.
   If we reflect on  these  consideraiions,  together with
 those which have been  already offered, we shall be  more 
ON  LIFE AND DEATH.
325
and more convinced—1st, That the great sympathetic is
only an assemblage of small nervous systems, having each
of them a ganglion for  its centre, and all of them inde-
pendent  of each other,  though generally communicating
with the spinal marrow and between themselves.   2dly,
That the nerves belonging to these small systems, cannot
be considered as a part of the great  nervous  system of
the animal life.  3dly,  That the organs, which are pro-
vided  exclusively  with the  nerves,  are not  under the
immediate influence  of  the brain.
   Notwithstanding which, we  must not suppose  that all
the organs which serve  for the internal functions,  receive
their nerves exclusively from the ganglions: many of
these organs are furnished from the brain, and yet from
experiment,  it is found  that they are not  under the imme-
diate influence of  the brain.
   As yet we have only observation and reasoning for the
basis of the  important  principle which we  are labouring
to establish,  namely, that the  organic functions are not
directly put  a stop to in consequence of the death of the
brain ;  but experiments upon living animals are not a less
evident demonstration of this principle.
   1st,  I  have  always  observed, that in producing palsy
or convulsion, I have never been  able to  impair  in any
very sensible or  sudden manner, either the  exhalation,
the absorption, or the nutrition of the convulsed or palsied
part.
   2dly, It has been for a long time known, that no spasm
of the muscular fibres of the  stomach, bladder, or  intes-
tines, can be produced by irritating the  nerves of the
 ganglions which go to  these organs.
   3dly, The division  of the  nerves  of the  ganglions,
 will  not immediately paralyze the hollow organs.   Their
 vermicular  motions  continue  for a long time after the
 experiment. 
326          PHYSIOLOGICAL RESEARCHES

   4thly,  With respect to the stomach, intestines, bladder
and uterus,  I have  repeated the galvanic experiments
which, with  respect to the heart, have  already been men-
tioned at  length; butnever  could obtain contractions.*
   5thly,  The  same  experiments being  made upon the
organic muscles, and the great S3 mpathetic  nerve of a
dog, there was no contraction.
   6thly,  The issue of the latter operation may be easily
conceived, according to our manner  of regarding  things.
In  fact, the  ganglions, which are situated  between  the
gastric organs and the nervous trunk of the chest, might
possibly have interrupted the series  of the galvanic phe-
nomena.   With a view, then, to remove all doubt of this
kind, I exposed the  nerves, which go from the ganglions
immediately  to the stomach,  bladder and  rectum,  and in
this way galvanised  the organs but no contraction appear-
ed to me  to be the result of  the experiment;  at least no
contraction,  which I  could  suppose to  be  the  effect of
galvanism, for here I cannot  too  much  recommend a
proper distinction to be made between  that which  should
be the effect  of this  fluid, and that which results from the
mechanical contact of the metals.
   7thly,   These experiments are not easily made upon the
intestines, on account of the tenuity  of their nerves; but
as these nerves compose a very perceptible  plexus about
the mesenteric artery, the intestine may be galvanized by
surrounding the artery with one of the metals, while the
other is placed  under the intestinal  tube.  This experi-
ment I  have made,  but could not  obtain  any sensible
result.

  * The galvanic stimulus usually produces very evident effects upon
the contraction  of the intestinal tube ; these  motions are less evident
in the stomach than in  any other  part of  the canal; but the same
difference is always observed whatever be the stimulus employed. 
ON LIFE AND DEATH.
327
  8thly, The preceding  essays were  made upon  warm
and red-blooded animals.  Similar attempts were repeated
on cold and red-blooded animals, but with no effect.
  Othly, The nerves which  immediately supply the gas-
tric organs of the frog, are  so delicate as to make it an
extremely  difficult matter to  get them into proper contact
vvith  the  zinc : a small contraction of the stomach was,
however,  obtained by  Jadelot on  operating directly on
these nerves ; but this contraction was similar, no  doubt,
to those which I have so  frequently observed in other
experiments, and  not to  be  compared to the astonishing
effects which are observable  in the voluntary muscles.   I
shall conclude, therefore, that with respect to the galvanic
phenomena,  there exists  a  wide  difference between  the
muscles of the animal life and those of the organic life.
   1 have now collected proof enough, I trust, for  resolv-
ing, vvith  certainty,  the  question proposed in the above
chapter, and  for establishing it as a fundamental  princi-
ple—1st,  That the  brain does not  directly influence  the
organs and the functions of the  internal life ; and 2dly,
That, therefore, the interruption of  these  functions, in
cose of any  great lesion of the brain, is not an immediate
effect  of such lesion.
   Nevertheless, I am  far from considering  the cerebral
action  as  foreign entirely  to the  organic  life.   I only
maintain that its influence  upon it  is indirect, and as yet
but  little  known.   I have  been  somewhat prolix upon
this subject; for certainly  nothing in medicine is more
vague than the sense which is commonly attached to the
words nervous action,  cerebral action, &c.   There  is
never  a  proper distinction  made between that which
belongs to one  life,  and that which is the attribute of the
other.   Cullen, in  particular, may be reproached with
having exaggerated  the influence  of the brain. 
328          PHYSIOLOGICAL RESEARCHES


II. Is the interruption of the functions of the organic
  life, the indirect effect of the cessation of the cerebral
  action ?

  The organic life continues to subsist for a certain  time,
after the apparent death of the  individual.  There must
be some intermediate agents then, the  cessation of the
action of which, occasions the death of the inward organs.
Such agents are  chiefly  the mechanical organs of respira-
tion.  The series of the phenomena are  the following :
  1st,  The cerebral actions  are  interrupted.—2dly, The
mechanical functions of the  lungs are put  an end  to.—
3dly,  There  is  an  annihilation of their chemical  func-
tions.—4thly, The black blood circulates  in all the parts.—
5thly,  The  movement of the heart and  the action of all
the parts is weakened.— Gthly, Suspended.
  All the inward organs then,  die  nearly as they  do  in
asphyxia; that is to say—1st, Because they are penetrated
by the black blood.—2dly, Because the  circulation censes
to communicate that motion  which  is essential to  their
life.
  Nevertheless, there are many  differences between death
from asphyxia,  and death from lesion of the brain.   1st,
The  animal life in the  latter sort of death, is  generally
interrupted at the very  instant of the shock or blow.  In
the former it is terminated only  in proportion as the  black
blood  penetrates the substance of the  brain.—2dly, In
the greater number of the asphyxiae, the circulation does
not immediately cease, the blood is only gradually black-
ened, and continues for some time to be  moved  onwards
by  the agitation  of  such parts  as are still under the
influence of the brain.   On the  contrary, in lesion of the
brain, the interruption of respiration is sudden ;  the  blood 
ON  LIFE AND DEATH.
329
also loses its red colour at once : on the  other  hand, the
animal life being suddenly arrested, the organs of volition
become immovable on the spot, and are capable no longer
of favouring the motion of the blood.   This remark is
particularly applicable to the breast, the parietes of which
facilitate very much the pulmonary circulation, and even
the movements of the heart by  their rise and  fall, for
in such alternation of motion  consists the true influence
which the circulation receives from the  respiratory pro-
cess.
   But after all,  these two  sorts of death  may be more or
less similar to each other  according to the way in which
they happen.  The differences  which I have pointed  out
are by no means general.   Thus, when  asphyxia  is sud-
den, as when for instance the air of the  lungs is pumped
out with a syringe, there are neither livid spots, or fulness
of the  lungs to be  met  with.   The circulation ceases
quickly, and the phenomena  of  death  are such  as  are
observable when the  brain is suddenly destroyed.
   On the contrary, if the  death of the brain be slow, and
the process  of  respiration for a certain  time continued,
the capillary system  of the lungs will  be gorged with
blood, and the general capillary system be filled also.  The
circulation in such  case will be slow to cease, and  the
phenomena of death  like those of many  of the asphyxiae.
Thus the promptitude or slowness of death, proceeding
from lesion of the brain, will occasion all the differences.
   It has been  often  a question in  what way criminals
die, who are hanged.  In  some, the vertebral column is
luxated, and in  others, want of respiration is the cause
of death.*   But whenever there is luxation, there is at
  * Death does not always take place in  the same way.  It has been
remarked, for example, that those who were hung at Lyons died quicker
than those who were hung at Paris.  In seeking  for the cause of this
             42 
330          PHYSIOLOGICAL RESEARCHES
the same time asphyxia, and in such  case asphyxia is pro-
duced, both bpcause the pressure of the cord  intercepts
the passage of the air, and  because  the intercostals  and
diaphragm are paralyzed.
  From  what 1  have  now  said, a  comparison  may be
made between  the three  kinds of death  upon  which I
have  expatiated.   This comparison,  according to  my
ideas, is of importance : I shall give some features of it.
Generally speaking, there is a  greater similarity in  the
two  modes by which  the  death of the brain,  or that of
the lungs produces the death of the organs, than  between
either of these  modes, and  that, where  the death of the
heart  is followed by the same effect.
  But 1st, There is always black blood in the red-blooded
system, when death begins either by the brain or the lungs.
When the functions of the heart are  suddenly suspended,
the arterial system contains a portion of red blood only.
  2dly,  In the  two fii>t cases, the circulation continues
for  awhile ; in the third, it is immediately suppressed.
  3dly,  When  the  death  of the  organs is a consequence
of the death of  the heart,  they die, because they cease to
receive that excitement, to which they are accustomed
from the motion  of the blood.  When their death is  pro-
duced by that  of the  brain  or  lungs, they die not only
because they lose the  excitement above-mentioned, but
because they are penetrated  by  a fluid  which is incapable
of keeping up their actions, &c.  The reader  will easily
finish the parallel which I have thus begun.

difference, it was ascertained that in those who were executed at Lyons
there was almost always a luxation of the first or the second vertebra
which was owing to a rotatory motion, which the executioner gave to
the criminal in throwing him from the scaffold.  The death was quick
because it was produced by compression or laceration of the spinal mar-
row ; it was slower in the other case in which it was only the result of
asphyxia. 
ON LIFE AND DEATH.
331
   In  red  and  cold-blooded  animals,  the  death  of the
organs succeeds much  more slowly  to  that of the  brain,
than in red and warm-blooded animals.   We cannot assign
the reason of this fact, because we do not know the differ-
ence of the arterial  blood from the venous blood of these
animals,  nor the ettect which is produced  on their organs
by the contact of either sort of blood with them.
   When reptiles remain  for a length of time under water,
does the  arterial blood  become  black  from  want of res-
piration ? is  the  influx  of such  blood  into their organs,
pernicious or  not?* or  is  there a sufficient  quantity  of
air contained  in the large vesicles of the  lungs of these
animals  to oxydate their blood  for a length  of time,  as
but little  blood is  capable  of passing into  the pulmonary

   * It appears by the beautiful experiments of  M. Edwards that frogs
can live but a  very  short time in water deprived  of air by  boiling.
Immersed in a  small body of water containing  air they soon die,  no
doubt after they have exhausted  the  air held in solution in the water.
They can on the contrary live an indefinite time in this  state of immer-
sion, if care be taken to renew the water sufficiently often.  The same
thing happens, and still  more  certainly, if they are immersed in run-
ning water.
   It is  not by  passing the water through the lungs, as the fish does
through the branchiae, that the frog obtains the air held in solution  by
the water  in which he is immersed, the  skin is  in  this  case the sole
respiratory organ.   M. Edwards is satisfied that this mode of respiration
is not sufficient to support life, except between certain limits of tempera-
ture ; a frog immersed  in a volume of water which is not  changed,
continues  to live so much the longer as the temperature of  thi* fluid
approaches nearer 32<\  At  this degree frogs are not torpid, as might
be supposed, only their motions are slower.
   As long as the animal immersed  in the water remains  perfectly alive,
which  may be known by the vivacity of his  motions, it is certain that
the respiratory phenomena continue to be performed by him ; we see
in fact on  the membranes  in the interstices of the toes, the vessels
filled with vermilion blood.   When the black colour begins to appear,
the animal soon becomes immoveable and insensible. 
332
PHYSIOLOGICAL RESEARCHES
artery, which is only a branch of the aorta.   The latter
opinion appears to be  confirmed by  the experiment of
injecting  the  lungs  of a dog vvith  a large  quantity of
air, in  which  case the blood of the creature is  reddened
for a greater  length  of time.   But all  these questions,
notwithstanding the essays  of Goodwyn, require much
elucidation.
                  CHAPTER  XIII.

OF THE  INFLUENCE OF TEE DEATH OF THE BRAIN OVER
           THAT  OF THE BOOT  IN  GENERAL.

  From the  consideration of what has been  said in the
preceding chapter, nothing can be more easy than to form
an accurate idea  of the manner in which the  phenomena
of general death, commencing by the brain, are concate-
nated.   The  series is as follows :
  1st,  The cerebral  action is annihilated.  2dly, There
is a sudden cessation  of  sensation  and voluntary motion.
3dly, A simultaneous paralysis of the  intercostals  and
diaphragm.  4thly, An  interruption of  the  mechanical
phenomena of respiration  and  the  voice.  5thly, An
annihilation  of the  chemical phenomena of  the lungs.
6thly,  A passage of black blood into  the arteries.  7thly,
A slowness  of circulation  owing to the  influx of such
blood into the arteries, and the absolute immobility of all
the parts, of  the  intercostals and diaphragm in particular.
Sthly,  The heart dies and  the general circulation ceases.
9thly,  The organic  life vanishes.    lOthly, The animal
heat, which is the product of all the functions, disappears.
llthly, The  while organs  die. 
ON  LIFE AND DEATH.
333
  Though in  this kind of death, as well  as  in the two
preceding kinds, the  functions are suddenly annihilated ;
the parts retain, for a  certain time, a  number  of the
properties of life.   The organic sensibility and contrac-
tility,  continue  for  some  time, to  be  manifest  in  the
muscles of the two lives ; and in those of the animal life,
the susceptibility of being  affected  by the  galvanic fluid
is very great in  the muscles of the animal life.
  This permanence of  the  organic  properties, is nearly
the same  in  every case ; the only cause which affects it,
is the slowness vvith which the phenomena of death have
succeeded each other.   In every case where their duration
has been the same, whatever may have been the cause  of
death, experiments  instituted upon these properties, are
attended with similar results;  for it is evident that con-
cussion of the brain, luxation  of the  vertebra?, the section
of the spinal marrow, apoplexy, compression of the brain,
or inflammation, are all  of them causes which are attended
with a like effect.
   The same, however,  is not the case with respect to the
asphyxiae produced  by the  different gases.   We  have
shown the reason of  this in  the  more or less deleterious
nature of the gases which  produce asphyxiae.
   The state of the lungs also, is very various in the bodies
of persons  who have  died from  lesions  of the- brain.
This  organ is sometimes  gorged and  sometimes almost
empty :  it  shews,  however, whether  the death of the
individual has been sudden or gradual.   The same indica-
tion may  be had from the state of the exterior surfaces.
   The death, which is  the consequence of disease,  com-
mences much more rarely in the brain, than in the lungs.
Nevertheless, in certain paroxysms of accute fever, the
blood is violently  carried to the head, and is the occasion 
334         PHYSIOLOGICAL RESEARCHES, &c.

of death.   The concatenation of its phenomena, are then
the same as take place in sudden death.
  There are a great  number of other cases besides those
of fever, where  the  commencement of death  may be in
the brain,  though the  brain itself may not  have been
previously  affected by  the  disease.  In these  cases, the
state of the lungs is very various ;  but little can be learnt
from it  with respect  to  the nature of the disease.  It is
only  an indication of the manner in which the functions
have been terminated. 

4?  ** 
 
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