VIVISECTION:
WIhIAT  IrT IS,
AND'VI-ATk  IT  H-AS  ACCO1MIPIISIIED.o
BY  JOHN  C. DALTON,    iD.D.,
Professor of Physiology in the College of Physicians and Surgeons, New York.
[Read before the New York Academy of Medicine, December 13, 1866.]
MR. PRESID)ENT AND GENTLEMEN2~ OF THE ACADEMY —AS the
subject of vivisection has been recently brought to the public notice in a way calculated to excite especial interest in its merits and
demerits, I have thought it appropriate to make it the topic of a
brief address, and to examine the question of its prolpriety and
usefulness, as a means of imnprovement in the medical art.  For
this purpose, I propose to discuss the objections which have been
urged against it, and to show how ifr they are valid,; and how far
destitute of foundation.
The objections urged against vivisection are principally threefold; viz.:
irSt, that it is cruel;
Secondcly, that it is liable to uncertainty and deception; andcl
Thirdly, that, in point of fact, it has not led to valuable results,
These three objections may be considered in succession.
First, as to its cruelty.  The injustice of this charge may be
appreciated, when we remember the aim  and motive of all such
experiments.  Their object is the improvement of medical knowledge, and consequently the relief of human sufferinc and the cure of
human diseases.  Physiologists have sometimes been chalrged with
recklessness and disregard of the lower creation in fbllowing out
their passion fobr experiment; and it is said of one of them  that
he destroyed, in the course of his life, "no fewer than three hundred and seventeen animals," with this object.  Now  if we destroy, every year, four hundred thousand cattle in South America* for no other purpose than to supply ourselves with boots and
shoes, it does not seem  a very reckless or extravagant thing to
sacrifice a comparatively small number of dogs and rabbits for the
~ The number of hides imported into the United States, during the year 1865,
from Buenos Ayres alone, was 400,978. From the whole of South America,
525,438.




2                         Yivisection.
acquisition of knowledge which is to benefit the human race.
This is a legitimate and praiseworthy object; and experimental
vivisection is no more open to the charge of cruelty on this account, than the dissection of human bodies for the study of anatomy is open to the charge of sacrilege and impiety.
Besides, it can never be properly the aim of the physiologist to
inflict unnecessary suffering. On the contrary, it is desirable on
every account to avoid doing so.  No class of' men can be more
averse to the infliction of suffering than the physicians and naturalists who make the functions of the animal organism  their
special study; and none are better qualified to judge of the existence and degree of sensibility in particular cases.
It is perfectly true that vivisection may be and has been abused,
in certain instances, by reckless, unfeeling, or unskilful persons,
But this abuse of a practice, which is rare and exceptional, cannot with any reason be urged against the practice itself when
conducted with judgment and propriety.  I have myself witnessed this abuse, especially in the case of a veterinary institution
in a foreign country, where the pupils were allowed to practise
surgical operations on the living and sensitive animal, for the purpose of learning the operative manipulations.  Nothing could be
more shocking than the performance of these operationls. Many
of them were evidently cruel and unnecessary, and excited the
hearty condemnation of all who visited the place. But this practice had nothing to do with physiological investigations. It was
confined to veterinary institutions abroad; and neither at that
time, previously nor since, so far as I am aware, has it ever been
in any way resorted to in this country.
It is also proper to remember that the great majority of cases
of painful operation on animals, for physiological experiment, date
from a time anterior to the discovery of ether and chlorofobrm
when surgical operations on the human subject were equally painful. Since the discovery of anmsthetics, their use has been adopted by the physiologist as promptly as by the surgeon; and inpoint of fact, at the present day, the great majority of physiological experiments are so performed as to be entirely painless. The
protecting influence of' anmsthetics, when fully administered, is
absolute and complete, and the most extensive incisions may be
performed without the animal experiencing the least consciousness
of the operation. The infliction of pain, therefore, as a general
rule in physiological operations, has no existence, and does not
apply as an objection to the practice.
But there is a very small class of cases in which anesthetics
cannot be used; and these cases present a difficulty to the minds
of some, who are ready to acknowledge the propriety of vivisection in other instances. For here, at least, the animal must
feel. Not being etherized, he remains sensible; and that degree
of pain which naturally attends the experiment cannot, in such a
case, be avoided.




Vivisection.                       3
Now the difficulty which prevents the use of ether, in these
cases, is a perfectly simple one.  They are cases mainly of experiment upon the nervous system, in which it is required to ascertain
the existence or non-existence of sensibility in particular parts.
Of course, therefore, if the sensibility of the animal were already
suspended by ether, there would be no means of judging of' its
existence or otherwise; and the operation could have no possible
result. If the experiment be done at all, therefore, it must be
done without the use of ether.
But a little examination will show how small, in reality, even in
these cases, is tile amount and friequency of unavoidable suffering;
and how exaggerated are the pictures which have sometimes been
drawn of their harshness and inhumanity.  For, to begin with, it
is not all experiments, even on the nervous system, lwhich are accompanied by pain.  Contrary to what might be anticipated, observation has shown that many of the nerves and nervous centres
are insensible, and cause no pain when exposed and manipulated.
Sir Cliarles Bell noticed many instances of this.  In speaking of
the two classes of nerves, and the sensibility of one of them, he
says: " While, on the contrary, nerves not of this original class
or system  are comparatively so little sensible as to be immediately distinguished, insomuch that the quiescence of the animal
suggests a doubt whether they be sensible in any degree whatever."
Again he says, in the same connection: "If the fifth nerve
and the portio cliera of' the seventh be both exposed on the face
of a living animal, there will not remain the slightest doubt in the
mind of the experimenter which of these nerves bestows sensibilitv."' f
Also in reporting his Experiments on the AVerves of the Fctce ~
"An ass being thrown, the portio dnra was divided on one side
of the head.  On the division of this nerve, the animal gave no
sign of pain."J
Again: "This experiment of cutting the respiratory nerve of
the tfce, orportio dscra, gave so little pain, that it was several
times repeated on the ass and dog, and uniformly with the same
result."~
In describing still another experiment, he says: "' In cutting the
portio dura, it was not evident that the animal suffered any pain
at all."11l
This fact has also been often observed with regard to the pneumogastric nerve, which may be divided in the middle of the neck,
without showing any sign of sensibility whatever, or one only of
a very obtuse character.
* Bell, Nervous System of the Human Body, 3d Ed., London,]1844, p. 42.
f Ibid. p. 42.
Philosophlical Transactions. Vol. XXXI., p. 412.
Ibid. p. 413.
b Ibid. p. 417.




4                         Vivisection.
The same thing is true with regard to a large portion of the
nervous centres. No fact is better established in physiology than
that the entire substance of the hemispheres of the brain, the cerebellum, the olfactory ganglia, the corpora striata, and the tubercula
quiadrigemina, are completely insensible.  Consequently when the
cerebral lobes of a bird or quadruped are wounded or removed,
this is an operation which produces absolutely no pain wvhatever.
The truth is, that ordinary sensibility is localized, like other nervous functions, in particular parts of the nervous system, and is
not to be found elsewhere.  Accordingly, the experiments which
have demonstrated this truth are doubly valuable: first, by showing the fact that sensibility is so localized in particular parts; and
secondly, by showing upon what portions of the nervous system
we may continue our investigations, without the production of pain
to the animal.
Beside, in these cases of experiment on the nervous system, the
preliminary operation of cutting through the flesh and subjacent
parts may, in most instances at least, be performed under the influence of ether, and the final examination alone take place after
the animal has recovered from his etherization.  This reduces the
actual infliction of pain to very narrow limits, both in respect of
deglree and duration.
This may easily be appreciated from what sometimes occurs in
medical practice. Suppose we have a patient suffering from apoplexy and partial hemiplegia, and we wish to know whether sensibility remains unimpaired in the affected part. In order to determine this, we do not require to torture the patient, nor to subject
him to any barbarous or extensive injury.  Just so much impression is required as will reveal the presence or absence of sensibility;
and, when that is done, the work is accomplished.  Now the
experiments upon the nervous system of animals, to which I allude,
are of precisely the same nature. Their object is the same, and
the means employed often identical.  When sensibility exists, the
pain which indicates it is momentary in duration, and need not be
excessive or violent in degree; when it does not exist, of course
there is no pain whatever.
I believe, thereforei, that vivisection, when practised with care
and judgment, is not open to the imputation of cruelty; but that
both the objects for which it is undertaken, and the manner in
which it is performed, place it beyond the limitations of such a
charge.
The second and third objections which have been enumerated
may be best examined in connexion with each other.
In order to place the matter in its proper light, let us therefore
consider as briefly as possible: first, what experimentation upon
livinc animals is; and second, what it has accomplished.
First of all, this method of study comprises all varieties of experiment performed upon living animals. The term " vivisection "
does not, fully express its character; fiol, although cutting opera



IVivisection.                       5
tions are often a part of the means employed, they are not always
so, and the essential nature and objects of the investigation are
the same in either case. It makes no difference, of course, either
for or against the propriety of this method, Mhether we experiment upon an animal by cutting his carotid artery, or by confining him in an atmosphere of oxygen or carbonic acid. The particular means employed vary, of necessity, with the special object
to  be accomplished.  But, in all instances, the distinguishing
character of experiments of this class is simply that they are performed upon the living body; and this distinguishing character is
the same, whether we operate upon the animal by means of incisions and ligcatures, by subjecting him to the respiration of particular gases, by confining him  to a regimen of fbod, peculiar
either in quantity or quality, or by the administration of drugs
and medicines.  The subject of discussion is not, therefore, vivisection in its narrowest sense, but the entire method of experiment
upon living animals, as a means of study in physiology and the
kindred sciences.
Now it may be stated, to begin with, that this method of investigation is the only one by which physiology can be successfully
studied.  This fact is now perfectly well settled by the results of
long experience, and many attempts to accomplish the same end
by other means.  Physicians have often endeavored to guess at
the vital properties of the internal organs, or to infer their functions fi'om analogy; but these attempts have nearly always failed
of their object, and have often resulted in complete deception.
The physiologists who relied upon such means have been fiequently misled in a direction exactly contrary to the truth; and
the real solution of the question has only been reached, afterward
by a resort to direct experiment on the living body.  In 1809, the
anatomy of the spinal nerves and their double origin, by anterior
and posterior roots, friom the spinal cord, was already kinoNwn.  At
that time, Alexander Walker conceived thle idea on theoretical
grounds that the anterior roots of these nerves were sensitive in
their function, and the posterior roots endowed with the power of
motion. It was only afterward, when Sir Charles Bell, Magendie,
and others, experimented directly upon these parts, in various animals, that W alker's surmises were found to be exactly wrong; and
that the anterior roots are in reality the organs of motion, and the
posteirior roots the organs of sensibility.  After the discoveries of
Lavoisier, in 1780, in regalrd to respiration, it was thought that the
blood became heated in passing thlrough the lungs. But subsequent
experiments made it evident that the lungs are not perceptibly
warmer than the other internal organs; and Bernard,* many
years afterward, by carefully introducing thermometers into dif:
ferent blood-vessels in the living animal, showed that, in point of
fact, the bloocl is a little warmer on the right side of the heart
* Cl. Bernard. Liquides de l'Organisme. Paris, 1859. Vol. I., p. 110.




6                        Vivisection,
than on the left, and accordingly that it becomes cooled rather
than heated in its passage through the lungs.
These are some instances of the inefficacy of surmises or analogical inferences as a source of knowledge in physiology, when
compared with direct experiment.
Now the reason why experiments on living animals are the
only source of certain knowledge in physiology is a very simple
one. Physiology is the study of the vital actions of the living
body; and these actions do not take place anywhere but in the
living body, and consequently cannot be observed or investigated
anywhere else. A complete knowledge of anatomy may be obtained by dissection of the organs after death; but their vital
functions are not to be learned in this way, because they have
ceased, and cannot again be put in operation. The most remarkable facts have sometimes remained unknown or misunderstood for this reason. The lacteal vessels, for example, were discovered by Asellius, in 1622; and though they had often been
seen in the bodies of recently killed animals subsequently to that
time, it was thought, fiom their small size and the small amount
of fluid contained in them, that the circulation of chyle must be
very limited in quantity. But in 1856, when these vessels had
been known to anatomists for over two hundred years, two French
physiologists introduced a canula into the thoracic duct of living
animals, continued the experiment while digestion and absorption
were going on, and obtained in this way, in horses, firom forty-five
to fifty pounds of lymph and chyle in twenty-four hours, and in
oxen fiom eighty to one hundred pounds in the same time,* a
quantity which was never before even suspected; and revealed
in this way an activity of one of the vital functions far beyond
anything which could be surmised from examination of the dead
body.
The chemical actions, also, which go on during life are only to
be learned by their investigation in the living body. For the
chemical reactions which take place in the test-tube and crucible,
by the manipulations of the chemist, are modified and altered in
the interior of the body by the various influences which surround
them there; and it is impossible to guess what these alterations
will be, until we try the experiment directly on the animal during
life. Any endeavor to anticipate or infer these changes, without
direct experiment, always results in a mistake, and retards our
knowledge instead of advancing it. It is perfectly true that
examinations of the dead body and ordinary chemical experiments are exceedingly useful as preliminaries, by suggesting
probable ideas or supplying convenient materials; but the final
question must always be decided by an examination of the functions as they actually take place during life.
* Colin. Physiologie Compar6e des Animaux Domestiques. Paris, 1856.
Vol. II., ). 100.




Vivisection.                     7
It is therefore certain that if our knowledge of physiology is to
be advanced at all, it must be by means of experiment on living
animals; since there is no other method upon which we can rely.
There is no other way of learning what the vital functions really
are, than by seeing how they take place while life is actually
going on. We might as well expect to learn the phenomena of
magnetism  by experimenting with substances not magnetic, as
to study the phenomena of life anywhere but in the actions of the
living body.
In the next place, the method by experimenting upon the living
animal is capable of being employed with judgment and practised
with success. This has not always been conceded to it; and the
olectionr is sometimes made that it is, for various reasons, uncertailltand fallacious, and that it is unlikely to lead, in any case, to
valuable results.
The most frequent form in which this objection presents itself
is that, in operating upon the living animal, we violate and disturb
the vital functions to such a degree that they exhibit unnatural
appearances, and so lead to erroneous conclusions.  It is said that
the necessary steps of the experimental operation-the incisions,
ligatures, mutilations, etc.-place the organs in an unnatural condition, and interfere with the regular performance of their fuinctions;-so that they vitiate the results of the experiment, and
render them worthless or deceptive.
This objection, however, is one which certainly would never be
made by a practical experimenter, for the reason that the difficulty to which it refers is always present to his mind, and one
against which he guards by unremitting precautions. This is the
very first and simplest lesson which is learned by the experimental physiologist.  We might as well object to the researches of
the astronomer that the refractive power of the atmosphere distorts the rays of light passing to his telescope, and thus vitiates
his observations. The astronomer is perfectly familiar with this
refractive'power of the atmosphere.  lie knows the mode of its
operation, and makes due allowance for it in his calculations. So
the physiological experimenter, in prosecuting his observations on
the living body, sees at once that the external agents which he
employs in his operations, themselves exert a certain amount of
influence in producing the result. It is always his object, in arranging an experiment, to reduce these disturbing influences to
the smallest possible compass. It is firequently necessary to vary
the method of procedure for the same experiment, in order to
determine how much, if any, of the final result is attributable to
the principal conditions, and how much to the accessory manipulations. Abundant instances of this are to be found in the history of investigation upon almost every physiological question;
and he would be a bungling experimenter indeed who should
leave out of consideration the physical conditions which he had
himself employed in operating upon the living body.




8                         Vylivisection.
This objection, therefore, is not something which has been
neglected or overlooked by physiologists; but, on the contrary,
it is better understood by them  than by any one else. In order
to illustrate how old a tlhing this objection is, and how frivolous a
form it has sometlmes assumed, let me quote an instance which
happened in connexion witlh the discovery of the circulation of
the blood.  in the time of Harvey, two hundred and forty years
ago, it was believed that the blood in the veins moved from the
heart outward toward the extremities.  I-Iarvey asserted that it
moved in exactly the opposite direction, viz., fiom the extremities
toward the heart,; and the proof of this was that when a vein was
divided, while the circulation was going on, all the blood flowed
fiom  the end near the extremities, whence it was coming, but
none of it fiorn the end toward thle heart, whither it vwas going.
But this plain experiment did not satisfy his opponents, who made
to it the objection which we have been considering; and Harvey
replies to them in this wayv:"And that no one," he says,  " may seek shelter in asserting
that these things are so when nature is disturbed and opposed,
but not when she is left to herself and at liberty to act; that the
sarne things do not come to pass in morbid and unlusual states as
in the healthy and natural condition; they are to be met by saying that if it were so, if it happenedcthlat so much blood was lost
fiom the fuirther orifice of a divided vein because nature was disturbed, still that the incision does not close the nearer orifice, firom
which nothing either escapes or can be expressed, whether nature
be disturbed or not."
It was IHarvey, therefore, who appreciated fairly the influence of the disturbing causes in this case; while those who
distrusted him  were reduced to the preposterouis assumption
that cuttinc a vein toward the heart prevented the blood fiom
flowing out of it, and that cutting it toward the extremities produced a current which did not previously exist. The physiologist,
therefore, was iight, and his olpponents were wrong.
We must recollect, also, that mechanical contrivances and
operations are an absolute necessity in physiological experiment.
If the fuinctions and processes of the living body Awere plainly exposed to view and capable of being learned by simple inspection,
there would be no need of experimelit of any kind. It is because
they are, in fact, concealed firom  observation, and carried on in
the secret recesses and cavities of the body, that we are obliged
to resort to experiment fobr their investigation.  Even for the
most palpable and external of the vital phenomena, as, for example, the inhalation and exhalation of gases by the breath, some
artificial contrivance is necessary in order to secure accuracy in
our results. These artificial contrivances, accordingly, when properly used, so far fiom being a source of deception for the physio* Works of Harvey, Sydenham Edition. London, 1847, p. 121.




Vivisection,                       9
logist, are the necessary instruments by which he is enabled to
accomplish his ends.
There are other difficulties, however, beside that just mentioned
in the way of physiological investigation; and thley require to
be met by certain plain and simple practical rules,  which are perfectly well known to physiologists, and universally adopted by
judicious experimenters.  Physiological experiment in fact is an
art, which is to be learned, like other arts, and practised with
care and judgment in order to be successful.  Let me mention some of these difficulties, and the means by which they are
avoided.
I. In the first place, the principal peculiarity which distinguishes
the phenomena of organic life is that they are com29ica.ted. The
result of a physiological experiment is often not a simple one, as
in physical and chemical investigations, but deplends on the combined oleration of various forces, each of which exerts its own
share of influence. The same phenom-enon, therefore, is susceptible
of various interpretations, until we have mastered all the elements
which combine for its production.  If the pneumlogastric nerves,
for example, which are distributed to the lunngs  be cut off in the
middle of the neck, this operation after some days stops respiration and produces a peculiar engorggement and solidification of
the lungs, by which they are rendered incapable of suipportingo
life.  But this is not owiing to the direct influence of these nerves
upon thle lungs; for they also send branches to other organs, and
espcially to the larynx, by the recurrent or inferior laryngeal
nerves. The natural movements of the larynx in respiration are
necessary to the healthy action of the lungs.  The substance of
the lung, accordingly, after division of the pneuluogastrics, is
solidified and en(gorged, not because its own nlerve has been cut
off, but because the branch distributed to the larynx ilas been cut
off at the same time. The proof of this is, that if the recurrent
laryngeal nerve be divided on both sides, the pneumogastrics remaining uninjured, the lungs after a time present the same kind
of engorgement and solidification as in the former case.
A similar relation of this nerve and its branches was recocgnised
by Galen, while studying the influence of the pceumogastrics in
the formation of the voice.
" A  lesion, accordingly," as Galen says,* " of these latter
nerves destroys the voice, because the special nerves of the throat,
which I call the'recurrent nerves,' foirm  a part of their substance. And though the former are distributed to miany different
parts, the latter, which belong especially to the vocal organs, have
a particular claim to be regarded as the vocal nerves."
II. In the second place, the vital phen:omena are vacriable at different times. The living body is not an inert structure, composed
of unchangeable materials.  It is an active and impressible organ* Galen, De Locis Affectis. Book I., Chap. VI.




10                        Vivisection.
ization, susceptible to the influence of external causes, and subject
also to variations of an internal and periodical nature.  It is most
necessary, therefore, in performing, a series of experiments for any
purpose, that the surrounding conditions should be always absolutely identical. The quantity of material used, the quality of
the instruments, the time and order in which the different steps
of the operation are performed, should all be arranged with precision; for any of these circumstances are liable to influence the
result. If a quantity of venous blood be drawn fiom the ox, and
shaken up with atmospheric air, it immediately changes color, and
assumes a bright arterial hue. But if another specimen of blood
be drawn fiom the same animal in the same way, and allowed to
remain at rest for forty-eight hours, and then shaken up as before,
but little or no change in color takes place; for the blood, after
being drawn fiom the vessels, suffers an alteration which Lenders
it less susceptible to the reddening influence of the air.
The condition of the animal as to rest and activity, youth or
age, fasting or digestion, will exert a similar influence. Blood
drawn from the portal vein, while fasting, will present a clear and
transparent serum. If drawn from the sanme vessel during digestion, its serum will be turbid and milky from the absorption of
chyle. The blood of the renal veins, while the kidneys are at rest,
is dark-colored like the average of venous blood.  When these
organs are in active secretion, it is bright and florid, like arterial
blood, and circulates with greater rapidity than before.  Consequently, the blood of the portal vein and that of the jugular vein,
if examined in the same animal while fasting, will be alike; if examined during digestion, they will be different. If the blood of
the renal veins be examined while the kidneys are at rest, it will be
venous in color: if examined while they are active, it will be arterial.
These variations, therefore, in the physiological phenomena, are
not productive of deception when properly examined; but on the
contrary, are the sources of greater knowledge, and lead to further discoveries.  All the natural phenomena are variable to a
certain extent, but they vary according to certain definite laws,
which may be discovered and understood by proper investigation.
It follows friom this that any apparent contradiction in phlysiological experiment, instead of destroying the value of its results,
may in reality enhance our knowvledge, and open new paths of
inquiry.  This has very often happened in physiology, and has
been prod uctive of the most valuable discoveries.  It would therefore be a most injudicious thing for the experimenter to neglect
or throw aside any phenomena which he may notice, because
they appear to be in opposition to others previously observed.
This would be entirely wrong; for, provided both sets of observations be carefully mnade, the last is as important as the first. To
neglect a fact actually observed is as much a falsehood in science
as to imagine one that has never been seen. Neither the new




Vivisection.                       11
nor the old observation, accordingly, is to be disregarded, but
equal value should be given to both.  If there be any apparent
discrepancy between them, they will certainly be reconciled by
subsequent investigation.
III. Thirdly, in experimenting upon living animals, there is a
certain caution to be observed in comparing the results of the
same experiment in animals of different species.  This is very
important; first of all, because different animals vary in their mode
of life, in the details of anatomical structure, and in the activity of special functions,-and also because they all differ, more or
less, fiom the human species, whose physiology is the particular
object of our study.  Now the rule to be adopted for our guidance in this respect, is as follows: Every experiment on the living
body has usually two different results, viz. a direct result, and an
indirect result; the direct result being due to its effect Gn the particular organ interested, while the indirect result follows, in a secondary manner, upon the disturbance caused among several
associate organs, and is due to the relation existing betwveen
them.
Thus, the division of the spinal cord causes immediately paralysis of motion and sensibility in the parts below. The paralysis
of the bladder also causes retention of the urine, consequent decomposition of the urea into carbonate of ammonia, an irritating,condition of this fluid, and so, lastly, inflammation of the urinary
passages. Paralysis of the lower extremities is therefore a direct
effect of division of the spinal cord; —inflammation of the bladder
is its indirect effect.
Now it is found that in all animals having the same general
structure, the direct effect of a physiological experiment is the
same, or varies only in rapidity, intensity, and duration.  It is
thereforle always safe to draw conclusions firom  the resemblance
of these direct effects in different species. The whole usefulness
of physiological experiments depends upon the fact that the general structure and functions of the animals employed fobr that purpose are the same.  In all the higher animals there is the same
general arrangement of the skeleton, the same structure of the
spinal cord, a simrnilar distribution of the nerves; and the same
plrincipal organs of circulation, respiration, and digestion.  The
only difference between them is in the relative size and proportion
of different parts, but not in their essential characterl. Their functions accordingly are identical.  In all these animals the anterior
roots of the spinal nerves are motor, and the posterior roots sensitive.  In all, the lungs absorb oxygen and exhale carbonic acid.
In all, the stomach secretes an acid gastric juice which dissolves
the food. In all, the liver produces sugar, by the process of nutrition and secretion.
But when we come to observe the indirect results of an experiment, we find that it varies essentially in different animals, owing
io the variable importance of different parts.  Thus in all animals,




12                         Vivisection.
division of the spinal cord will produce paralysis of the hinder
extremities; but it will only produce inflammation of the hladder
in those animals in which the urine contains urea.  Division of
the seventh pair of nerves will paralyze the muscles of the face
in all species; but in the horse it also produces a serious impediment to respiration, because this animal can only breathe through
the nostrils, and the movements of the nostrils are therefore more
important in him than in other species.  The direct effect of an
operation, accordingly, which is always the same, is generally, also, the most important for our purposes; the indirect effect, which
varies in different species, is often useful in explaining the peculiarities of a particular function.
It is evident, therefore, that we must exercise a certain reserve
in applying the results of an experiment on the lower animals to
man, or to animals of different species.  If these results be direct
and immediate in the mode of their prodnction, it is always safe
to make application of them to the human subject; if they be indirect, we cannot do so with certainty until we have learned all
the successive steps by which they are produced.
IV. Finally, it is very essential for the experimental physiologist to be always acquainted with the indiviclual peculicarities of
the animals upon which he operates; and for this purpose he should
keep them under his observation for a certain time before performing an experiment.  For particular animals are distinguished by
individual peculiarities, to a certain degree, like the menlmbers of
the human species.  These peculiarities relate not only to the excitability of the nervous system, the degree of intelligence and
the mental disposition, but tlhey affect the entire organization in
its functions of nutrition, secretion, muscular contractility, etc.
One animal wvill habitually feed with appetite and relish, devouring a large quantity and digesting it readily. Another takes his
food sparingly, is fastidious as to its quality, and requires a much
smaller quantity than the first, though to all appearance equally
well nourished.  In one animal the secretions are either more
abundant or more easily excited than in another, the senses more
acute, the motions more varied and vigorous. It is particularly
in experiments upon the nervous system, in which the effect of an
operation is indicated so much by the state of the disposition, the
posture, 1manner of using the limbs, etc., that previous observation
of the individual habits of the animal is requisite; for wlhere the
effect of an experiment is to be seen in the increase or diminution
of a natural function, in order to appreciate these changes we must
have a proper standard of comparison in the ordinary habits of
the animal.
I have thus endeavored to show  what experimentation upon
living a-';mals is, and in what manner it is successfully practised.
Let us now see what it has accomplished.
This kind of experiment is by no means a new thing.  It has
been resorted to, at various times and by different observers, for




Vivisection.                      13
over seventeen centuries; and the periods at which medical science has especially advanced have been exactly those periods in
which it has been most assiduously employed.  Its results, both
direct and indirect, have been incorporated with the mass of our
medical knowledge, and have become so thoroughly a part of ourl
scientific pkrirnony, that the source firom which they were derived
is often overlooked.  But, in point of fiact, it is not too mnuch to
say that every ijmportant discovery in p]hysiology has been, directly
due to exe)eriments on living animals; and that we owe many of
those in practical medicine, surgery, and hygiene, either directly
or indirectly to the same source.
Let us enumerate some of these discoveries, and recall the
manner in which they have been made.
I. First, the Circulation of t~he Bloocd.  From the time of Hippocrates clown to the middle of tle second century, it was supposed
that only the veins contained blood, while the arteries were thought
to be tubes for the conveyance of air.  This was a very natural
conclusion firom such examinations as were miade at that time.
For those who opened the bodies of men or animals after death
found the veins full of blood, while the elastic arteries, having emptied
themselves into the veins and capillaries, resumed their cylindrical
form as soon as they were cut across and the air admitted to their
interior; so that the anatomist, seeing the open and gaping mouths
of these vessels, concluded that they were air tubes, and called
them "arteries'" on that account.  There were then, as every one
supposed, two kinds of vessels distributed throughout the body,
viz. the veins for conveying blood, and the arteries for conveying
air.
This error in regard to the arteries was detected by Galen, who
was accustomed to experiment upon animals, about the year 150.
In the first place, he opened the arteries while the blood was still
in motion, and showed that, however small the orifice, it was only
blood that escaped, and not air. This, however, did not satisfy
his opponents, who maintained that, in reality, air escaped first
from  the wound, only that it was invisible, and that the blood,
which was also discharged, was drawn into the artery firom distant
parts after the vessel had emptied itself of air.  To meet this
objection, Galen exposed an artery and included a portion of' it
between two ligatures.  Now, if the vessel were opened between
the ligatures, and if it in reality contained only air, nothing but
air could escape from it, as no blood could then be drawin into it
firom distant parts. Galen opened the vessel and found that blood
escaped as before.
"For we have often," he says,*' exposed the large arteries
convenient for this purpose, and asked the disciples of Erasistratus
whether the artery thus exposed did not seeim to contain blood.
* Galeni Opera. An Sanguis in Arteriis Natura contineatur.




14                      ivisection,
They were obliged to confess that it did, both because Erasistratus
asserted that the blood passed into the arteries when they were
uncovered, and because the fact was evident to the senses; for,
having placed ligatures on both ends of the inclosed portion of the
artery, and made an incision into the vessel between them, I
showed that the artery was itself full of blood."
This was the first great discovery made in regard to the circulation, viz. that the arteries, instead of servingr to distribute air,
are in reality filled with blood, which moves through them to its
destination.
But the remainder of the subject was still involved in obscurity.
The ancients were then acquainted with only two main fhcts in
this respect, viz. the introduction of air into the lungs, and the
movement of the blood in the vessels; but how these functions
were accomplished, and what was their mutual connexion, was
almost unknown. Their idea of the circulatory system, as improved by Galen, was this: The imesenteric veins, conming fiom
the intestine to the liver, brougiht to that organ the chyle, to be
worked up in its interior into the materials of the blood. The
blood, thus formed in the liver, was thence conveyed to the right
side of the heart. After its arrival, a part of it was supposed to
be filtered through small openings in the septum of the ventricles,
and so conveyed into the left cavities of the organ. The blood
which remained in the right cavities was venous blood, and was
immediately distributed, by the veins, throughout the body to the
different organs and tissues.  That portion which had passed
through the septum of the heart waas elaborated, in the left ventricle, into a new and more active kind of blood, called "spirituous" blood,-the same which we now know by the name of' arterial."  So the left ventricle was regarded as an organ for the
elaboration of' "spirits," as the liver was supposed to be an organ
for the elaboration of the blood; and by a mixture of the two
was produced " spirituous") or arterial blood, first tully formed in
the left ventricle.
Here, then, were two kinds of blood, venous and arterial, contained respectively in two different sets of vessels-the veins and
the arteries; but, according to Galen and his followers, both these
two kinds of blood Awere conveyed fiom the heart, as a centre,
outward to the organs and tissues, the venous current running in
the same direction with the arterial, so that every organ was supplied, as he supposed, with two kinds of blood-venous blood by
the veins, and arterial blood by the arteries.
This was the state of medical knowledge, in regard to the circulation, for more than a thousand years. It was somewhat
modified, in the sixteenth century, by Vesalius and Servetus, who
maintained that there were no openings in the septum of the
heart, leading from one side to the other, but that this communication took place through the vessels of the lungs, so that that
portion of the blood which passed from the right side of the heart




ivisectiono                   15
to the laft must make its way through the pulmonaryvessels and
not through the substance of the heart itself. Still this doctrine
attracted but little attention, and is acknowledged to have had
little or no influence on the progress of physiological ideas.*
Nothing, in fact, was changed except the place for the elaboration
or spiritualization of a portion of the blood; this elaboration
taking place, as Servetus said, not in the heart, but in the lungs.
The direction in which one-half the entire blood was supposed
to move was still exactly wrong; and the blood circulated obstinately in the veins fiom within outward, in all books of anatomy
and physiology of the sixteenth century. Even when Fabricius
of Aquapendente discovered by dissection that the veins contained
valves, opening toward the heart and shutting backward toward
the extremities, neither he nor his pupils ever thought of any other
use to attribute to these valves than that of preventing a too rapid
downward current toward the limbs. So impressed were they
with this fixed idea, that the blood passes from within outward
along the veins, that, with the valves actually under their eyes,
they did not see the physical obstacle thus presented to any current in an outward direction.
Notwithstanding the valves, therefore, the blood continued to
run the wrong way for three-quarters of a century after the time
of Vesalius and Servetus.
But early in the seventeenth century, Harvey began his investigations, and accomplished more than had been done by the accumulated labor of' centuries. His is universally acknowledged to
be the most brilliant discovery ever made in.physiology; and it
is difficult to imagine how any other single one of equal importance
can be made hereafter. For his researches changed the whole
aspect of one of the most essential functions of the living body,
and showed how thoroughly its nature had been misconceived
ever since the periods of antiquity.
Fromn what has already been said, it would be natural to suppose that Harvey supplied the existing deficiency, and made
everything right that was before wsrong, by the simple discovery
of the true motion of the blood in the veins, and its direction
from the extremities toward the heart. This, at present, seems
to be all that was wanting to clear up the previous obscurity, and,
at the same time, the most palpable fact yet to be discovered. It
appears to us almost the first thing with which a new investigator
would necessarily commence.
But it happened quite differently. Harvey began with the
motions and function of the heart; and the direction of the venous
current, instead of being the fact with which he commenced,
formed in reality the completion or termination of his work, in
the order of time.
In point of fact, the movement of the blood in the veins was
* Mile-Edwards. Physiologie. Paris, 1858. Vol. III., p. 17.




1 6                       Vivisection.
not the only thing in which the older physiology of the circulation
was at fault.  For the true mechanism  of the heart and bloodvessels was also entirely unknown. No one had any idea what
caused the blood to move, nor why it nmoved in any particular direction. There was no definite knowledge of the physical forces
of the circulation.  Harvey was sensible of this deficiency, and
accordingly he set to work to examine for himself, and to see by
actual inspection what was in reality the action of the heart and
blood-vessels. The account which he gives of his own attempts
in this work, his difficulty in at once understanding what he saw,
and the mnode in which he gradually came to comprehend the appearances and action of the parts, is a masterpiece for faithful and
graphic description, and for the candor and sincerity of purpose
which appear in every word.
" When I first gave my mind to vivisections," he says,* " as a
means of discovering the motions and uses of the heart, and
sought to discover these fiom actual inspection and not from the
writings of others, I found the task so truly arduous, so full of
difficulties, that I was almost tempted to think, with Frascatorius,
that the motion of the heart was only to be comprehended by
GOD. For I could neither rilghtly perceive at first when the systole and when the diastole took place, nor when and where dilatation and contraction occurred, by reason of the rapidity of the
motion, which in many animals is accomplished in the twinkling
of an eye, coming andc going like a flash of lightning; so that the
systole presented itself to me now fiom this point, now fiom that;
the diastole the same; and then everything was reversed, the
motions occurring, as it seemed, variously and confusedly together.
My mind was therefore greatly unsettled, nor did I know what
I should myself conclude, nor what believe fiom  others; and I
was not surprised that Andreas Laurentius should have said that
the motion of the heart was as perplexing as the flux and reflux
of Euripus had appeared to Aristotle.
"At length, and by using greater and daily diligence, and
collating numerous observations, I thought that I had attained
to the truth, that I should extricate myself; and escape fiom this
labyrinth, and that I had discovered, what I so much desired,
both the motion and the use of the heart and arteries.  Since
which time I have not hesitated to expose my views upon these
subjects, not only in private to my fiiends, but also in public, in
my anatomical lectures, after the manner of the Academy of old.'"
Harvey, then, begins with the action of the heart; and he tries,
as he says, " with greater and daily diligence," to understand
what it is. Ile sees that the heart shows alternately, and withi
rapid recurrence, two different appearances, a pause and a motion,
incessantly repeated one after the other. In the pause it is " soft,
flaccid, and lying, as it were, at rest."  In the motion it is hard,
* Harvey's Works, Sydenham Ed., p. 19.




Vivisection.                    17
erected, rises upward to a point, and "looks narrower and more
drawn together."  In the pause it is of a deep blood-red color;
and in the motion it becomes paler, as if emptied. He thus concludes that its motion is one of tension and constriction, like a
muscle, and that at this time it drives the blood out of it by contraction.
Now, this was the very opposite of what was before supposed;
for it was then thought that the stroke or impulse of the heart
happened at the time that it was dilated or filled with blood; not,
as it seemed to Harvey, when it was emptied. But Harvey did
not undertake this labor merely to replace one hypothesis by another, nor was it his disposition to make a bargain with probabilities. His genius led him at once, and without hesitation, to the
positive decision of this point, by making an incision into the ventricle and seeing when the blood was actually expelled.
" But no one," he says, "need remain in doubt of the fact, for
if the ventricle be pierced, the blood will be seen to be forcibly
projected outward, upon each motion or pulsation, when the heart
is tense."'
Having settled this point, Harvey goes on to the arteries; and,
comparing their dilatation and contraction with that of the heart,
he sees that the two sets of motions alternate with each other —
that the systole of the heart corresponds in time with the diastole
of the arteries, and the systole of the arteries with the diastole of
the heart; and that if an artery be punictured, the blood is driven
out fiom it at the time when the heart contracts, and when the
artery itself; therefore, is dilated.
Accordingly he concludes that the impulse, or diastole, of the
arteries is due. to the shock of the blood driven into them by the
contraction of the heart.
lHe gives his account of the motion of the blood through this
part of the vascular system, in a mnanner equally strikinc and
artistic, and with the most admniirable faithfiulness of detail. "Even
so," he says, " does it come to pass with the motions and action
of the heart, which constitute a kind of deglutition, a transfusion
of the blood fiom the veins to the arteries."  " And if ally one,"
he continues, 6 bearing these things in mind, will carefully watceh
the motions of the heart, he will perceive not only all the particulars I have mentioned, viz. the heart becoming erect, and making
a continuous motion with its auricles, but farther a certain obscure
undulation and lateral inclination in the direction of the axis of
the rioght ventricle, the organ twisting itself slightly in perfbl ming its work.  And, indeed, every one may see, when a horse
drinks, that the water is drlawn in and transmitted to the stomach,
at each movement of the throat; the motion being accompanied
by a sound, and yielding a pulse, both to the ear and touch; in the
same way it is with each motion of the heart, when there is the
delivery of a quantity of blood firom the veins to the arteries, that
a pulse takes place and can be heard within the chest."
2




18                        Vivisection.
Now, at the present day, the comparison of the arterial current
with the deglutition of water, throughl the gullet of a horse, seems
a coarse illustration of a familiar and delicate fiunction; but when
employed by Harvey, it was the bold and forcible expression of
an entirely unknown truth.  For at that time, though the course
of the blood through the arteries was known, the pulsation, both
of these vessels and of the heart, was altogether misunderstood.
The heart and arteries were thought to dilate simultaneously, by
an expansion, somewhat like that of the chest in respiration; and
the object of this motion was regarded, in a vague sort of way,
as a kind of fanning or refirigeration of the blood. The action of
the heart, as an inpulsive organ, was entirely unknown, and the
ventricle was considered, by the older anatomists, only as a place
for the production and elaboration of what they called "spirits,"7
and " spirituous blood."  If Harvey, therefore, had. done no more
than this, he would still have taken rank as one of the most eminent of medical discoverers.
But this was simply the beginning of his investigations, and an
introduction to his main discovery.
The venous blood was still thought to be distinct from  the
arterial blood. It passed, fiom  the vena cava and right side of
the heart, round through the lungs to the left ventricle; and fi'om
the left ventricle was driven through the arterial system, to the
various parts of the body. But that was all. What became of it subsequently was unknown, until Harvey, led onward by his first investigations, began to think, as he expresses it, " whether there might
not be a motion of the blood, as it were, in a circle," the whole
blood passing fiom the arteries to the veins in the extremities,
and again firom the veins to the arteries in the cavity of the chest.
Now- it is curious to observe in what way Harvey was at last
led to comprehend this truth, and to convince himself of its reality. It owas by estimating the quantity of blood passing through
the hecart in ca given time. Harvey saw that a considerable quantity of blood was driven out of the heart at each pulsation.  Estimating  this quantity at its lowest possible amount, —half an
ounce, three drachms, or even one drachm, according to the size
of the heart, —he was struck with the remarkable faet that, in the
course of half an hour or an hour, more blood passed through the
heart, fiom  the veins to the arteries, than was contained in the
whole body. As this passage was incessantly going on with Ahe
same rapidity, it was obvious that the necessary quantity of blood
could not be supplied, as Galen had supposed, from the fbod and
drink, since it would require at least forty or fifty times as much
food as is taken in the whole c urse of tuwenty-four houlrs. H-arvey therefore came to the conclusion that the same blood which
passes outward in the arteries is brought back, by a returning
current, in the veins. Finally, he came to the positive demonstration of this returning current, by opening the vein:,,* and
H Harvey's Works, Sydenhafn Edition, pp. 50, 53, 65, 120, 141.




Vivisection.                       19
tying and compressing them  at various points;-and thus saw
and proved that the blood returns to the heart by the veins, and
so, following a continuous round, performs the incessant movement
of the circulation.
Such was the history of the discovery of the circulation.  Let
us now pass to that of Respircation.
II. The first important acquisition in regard to respiration was
made by Sir Robert Boyle, in ]670.*  He employed for this
purpose the air-pump, then recently invented, by which he was
enabled to exhaust the air from a closed receiver. IHe experinlented on kittens, birds, fiogs, fish, snakes, and insects; and showed that in all these animnals the presence of atmospheric air is
necessary to the maintenance of life, and that when stupefied by
its witkhdrawal they may be resuscitated by readmitting it.  This
was confirmed, in a more positive manner, in regard to fish, by
the Swiss expelirnenter, Bernouilli,f who fbund that ordinary water
contains atlnospheric air in solution, and that when deprived of
this by boiling, it becomes unfit for the respiration of fish. In
this way it was established that in all species, both terrestrial and
aquatic, it is the atmospheric air which is essential to respiration.
The next inmportant fact discovered was that atmospheric air,
by continued breathing, becomes vitiated and unfit for respiration.
This -was shown first by Boyle, who, by confining animals in a
closed vessel, found that after a time they became suffocated, and
that, in order to keep up respiration, it was necessary to remove
the vitiated air and introduce a fresh supply.
The third point was established by MIayowr, in 1674, who, by
experimenting upon mice, found that by their respiration the air
was not only vitiated, but also diminished in volume.  He measured the amount of th}is diminution, and found that it was seven
per cent. of' the whole volume of the air.  He concluded that
something in the air was used up or consumed by respiration, and
he gave to this substance the name of " nitlo-a6real spirits."
Fourth, Priestley, in 1772,~ continued these experiments on air
vitiated by respiration, in order to determine how it might be
regenerated and again made capable of supporting life. He inclosed mice in tight receivers until the air was thoroughly vitiated
and rendered unfit for respiration.  He then subjected this air to
a great variety of processes, and again tested it by introducing
into it other mice.  He tried, in this way, the effect of long keeping, of the application of a higoh temperature, condensation, rarefaction, and contact with vegetable mould; all without success.
Finally, he found that by making plants grow in it the vitiated
* Boyle. Philosophical Transactions, Vol. V., pp. 2011-2055.
+ Milne-Edwards. Pllysiologie. Paris, 1857, Vol. I., p. 382.
J Ibid., p.:389.
~ Philosopliicai Transactions, Vol. LXI.,.p. 147.




20                        Vivisection.
air becalne regenerated, and again fit for the respiration of animals. I-Ie thus established the reciprocal relation of animal and
vegetable respiration; viz. that animals, by breathing, deprive
the atmospheric air of a certain property which is restored to it
by vegetation.
Black had already, a few years before, studied the properties
of carbonic acid —which he called " fixed air," because it is fixed
in the calcareous and alkaline carbonates —and found it to be a
product of the respiration of man and animals.
But the greatest advance in our knowledge of this function was
that made by Lavoisier, firom 1775 to 1780; —when he established, at alhnost the same time, the true composition of the atmospheric air and the part which it plays in respiration.  His experimnents, so far as they relate to our present subject, may be briefly
stated as follows. He deoxidized atmospheric air by the calcination of' mercury, and found: First, that animals could no longer
breathe in it; and secondly, that it had diminished in volumre.
He concluded that the atmosphere was composed of two airs
or gases; one respirable, the other non-respirable; that the
respirable air was that which had combined with the merlcury
(oxygen), and  the  non-respilrable  that which  was left behind. He then collected  the oxide of' mercury, reduced  it
again to the metallic state, examined the gas which was evolved
in this process, and found that it amounted to exactly the same
volume by which the air had been previously diminished. He then
added this evolved gas to the non-respirable residue, and found
that the mixture had again become respirable, and that animals
no longer died in it. These experiments were performed with
sparrow!s.
He then went further, and examined more closely the air which
had been vitiated by continued respiration.  He saw that, in its
incapacity to sustain life, this vitiated air resembled that which
had been simply deoxidized by the calcination of mercury. But,
on further examination, he found two points of difference between
these cases, viz. First, that the diminution of volume was much
less in one case tlan  in the other; and secondly, that the air
vitiated by respiration precipitated lime-water and consequently
contained carbonic acid, while the other did not. He found also,
that, in order to renovate the air which had been vitiated by
respiration, two things must be done. Not only we must take
away fiom it, by means of lime or a caustic alkali, the carbonic
acid which it contains, but we must also restore to it a quantity
of oxygen equal to that which it has lost. He established in this
way the following important conclusions:
First, that respiration acts only on the respirable portion of the
air, or oxygen, while the remainder, or nitrogen as we call it, is
entirely passive in the process; and secondly, that when animals
are confined in a limited space, they die when they have absorbed,
or converted into carbonic acid, the greater part of the oxygen,




Vivisection.                      21
and so reduced the atmosphere to the state of an irrespirable or
mephitic gas.*
In this manner were developed the two main features in the
process of respiration, viz. absorption of oxygen and exhalation
of carbonic acid.  Other details of interest and value have since
been added by other observers, relating to the time, place, quantity, and manner of the production and disappearance of these
two gases. But the principal facts were established at that time;
and our real knowledge of the function of respiration dates from
Lavoisier, as that of the circulation dates from Harvey.
There are two operations immediately dependent on the functions of circulation and respiration, the history of which is directly
connected with our present subject.
III. One is that of Tcratsfasion of tlhe -Blood  The earliest
form in which the idea of transfusion presented itself was that of
injecting into the blood-vessels certain medicinal agents. This
was first done in Engla,nd about the middle of the seventeenth
century, under the auspices of Sir Robert Boyle; at which time
it was shown that a solution of opium might be injected into the
blood-vessels of a dog, so as to produce a narcotic effect upon the
brain without killing the animal.
After the feasibility of this operation had been established, it
excited much interest in various parts of Europe. It seems even
that the priority of the discovery was a matter of some dispute;
for there appeared in the Philosophical Transactions of the Royal
Society of London, for 1665, the following communication, entitled,
"An Accotent of the -Rise and Attempts of a Wtay to conveigh
_Liqators immnediately into the ]fcxss of' Blood.
" Whereas, There have lately appealed in publick some Books
printed beyond the Seas, treating of the Way of injecting Liqnors
into VTeines, in which Books the Original of that Invention
seems to be adscribed to others besides him to whomn it really
belongs: It will surely not be thought amiss if something be
said whereby the true JIzventor's right may beyond exception be
asserted and preserved: To which end thele wvill need no more than
barely to represent the Time when and the Place where and among
whom it was first started and put to tryal. To joyn all these circumstances together'Tis notorious that at least six years since (a
good while before it was heard off that any one did pretend to
so much as thought of' it) the Learned and Ingenious )Dr. Christojpher W}ien did propose, in the University of Oxford (where he
is now the worthy Savilian Professor of Astronoimzy,. and where
very many curious Persons are ready to attest this Relation) to
that noble Benetactor to Experimental Philosophy, iW/. Robert
* Lavoisier. Experiences sur la Respiration des Animaux. Memoires de
l'Academie des Sciences Paris, 1i77.




22                         T-Vivisection.
Boyle, D)r. Will7ins  and other deserving Persons, that he could
easily contrive a way to conveigh any liquid thing  immnediately
into the MIass of Blood; videl.: by mtaking ligatures on the
Veines, then opening them on the side of tie ligature towNards
the heart, and by putting into them  slender Syringes or Quills,
fastened to Bladders (in the nmanner of Clyster-pipes) contalining
the matter to be ilijected; performing that ol.eration upon pretty
big and lean Doggs, that the vessels might be large enough and
easily accessible.
" This proposition being made, Mr. Boyle soon gave order for
an apparatus to put it to experiient; wherein at several times,
upon several doggs, Opium  ancd the infulsion of Croc?.s  jrfetcallorwum were injected into that part of the hind legs of those
animals, whence the larger vessels that carry the blood are most
easy to be taken hold of: whereof the success was thlat th.e opium,
being soon circulated inito the brain, did within a short time stupefy tho' lnot kill the dog.1"*
These researches were soon followed by those of Richard Lower,
on the transfLhsion of blood firomn the vessels of one animal into
those of another.  His first experiments were done in 1665, and
were reported by Mr. Boyle to the Royal Society in the following
year.  The experiments consisted in placing   a ligature upon a
dog's carotid artery, opening the vessel below the ligature, and
inserting  into it a quill of the proper size to serve for a canula. This
canula was then connected with the jugular vein of another dog,
so placed as to receive the blood coming fiom the carotid artery
of the first in a direction to pass downward to the heart and so
mingle with the nmass of the circulating current.  The jugular
vein of this dog was then opened above the insertion of the canula, and he was allowed to bleed fiom  it; the blood lost in this
way by the second dog being replaced by that which was transfused fiom the vessels of the first.
These experiments were quite'successful, and first showed that
death firom  hLtmorrhage might be prevented  by transfusion.
Lower, however,, found one practical difficulty in the performance
of the experiment, viz. that the blood of' the first dog sometimes
coagulated in the artificial tube and stopped the current; so that
he was obliged to take out the canula and clear it with a probe.
"For this must be expected," he says,f "L when. the dog that
bleeds into the other hath lost much blonlt, his heart will beat
very faintly, and then, the impulse of bloud being weaker, it will
be apt to congeal the sooner...  But to prevent this
trouble and make the experiment certain, you must bleed a great
dog into a little one, or a Mcastive into a (Cur7, as I once try'd,
and the little dog bled out at least double the quantily of his own
bloud, and left the Mastive dead upon the table, and after he was
* Philosophical Transactions. Vol. I., p. 128.
ibid. p. 353.




Vivisection.                       23
untyed, he ran away and shaked himself, as if he had only been
thrown into water."
These results soon led to the idea of performing the same operation on the human subject.  This was first done in France by a
physician and a surgeon, named Denis and Ernmerets.  They
were led to believe that the operation might result in the cure of
diseases by introducing healthy blood fiom a foreign source into
the veins of the patient; and some apparently successful results
of this kind excited among the profession great enthusiasm in its
favor. But these expectations soon proved unfounded, and several cases of failure afterward produced so much reaction against
it, that in 1668 the Parliament of Paris passed a law forbidding
the operation to be performed except by consent of the Faculty.
The matter remained in this condition until 1818, when Dr.
James Blundell, of London, brought back the operation to its
original object; applying it, not to the cure of diseases, but to
the preservation of life after exhausting hmmorrhage.  He also
discovered and exposed the principal error in the previous mode
of doing the operation; viz. the use of blood of anim:-ls of a
different kind, instead of those belonging to the same species.
lie performed thirty-three experiments on animals, and showed
by them:
1st. That dogs exhausted by h.mmorrhage may be resuscitated,
even after momentary stoppage of the respiration, by injecting
the blood of other dogs.
2d. That human blood, injected into a dog in large quantity,
sufficient to replace an exhausting hemmorrhage, though it produces a temporary reanimation, does not save life, but the animal
dies some hours afterwards.
3d. That transfusion of blood, in animals of the same species,
will be successfil, whether the blood used be arterial or venous.
4th. That blood may be received into a cup and passed through
a syringe, without being thereby iendered unfit for the purposes
of lift.*
The transfusion of blood, thus placed upon its proper footing,
and still further improved by the investigations of Prevost and
Dumas, Milne Edwards, Dieffenbach, and Bischoff, was adopted
by the profession, and is now known as an established and useful
operation, applicable to cases in which an exhausting hemorrhage,
in a healthy person, has brought the patient to the point of' death.
In these cases it has long been known, as mentioned by Blundell,
that there is an interval, often of several hours, after the haemorrhage has ceased, during which the patient is evidently sinking,
and when other means of restoration are of no avail. Berard has
recorded fourteen such cases, in which the operation of transfusion
was successful. They are as follows:t
* Researches, Physiological and Pathological; by James Blundell, M.D., London, 1824.
f BWrard, Cours de Physiologie, Paris, 1852. Vol. III.,, p. 219.




24                       Vivisection.
1st. A case of abundant hoemorrhage following delivery.  All
the signs of approaching death. Extremities cold; respiration imperceptible.  Two ounces of' blood were transfused by Blundell,
firom the husband, and the operation repeated a few minutes afterward. Recovery.
2d. By Dr. Doubleday. Uterine hlemorrhage.  The patient
was at the last extremity.  Six ounces of blood were tranfused
fiom the husband in three injections. The patient returned from
death to life, Recovery.
3d. By Brigham, of MIanchester.  Bleeding after delivery.
Loss of consciousness; cold extremities. Death near at hand.
Ten or twelve ounces of blood were injected at several times. At
the third injection the patient began to revive. Recovery.
4th. By Dr. Burton Brown.  HIImorrhage after delivery.
The patient presented a cadaverous aspect. Extremities cold;
pupils dilated; no pulse, either at the radial or carotid.  Three
injections of blood at intervals of five to ten minutes. Recovery.
5th. By Waller.  Uterine hbemorr-hage.  Death imminent.
Thirty-nine drachms of blood were injected at intervals of five
minutes. Recovery.
6th. By Banner, of Liverpool. Uterine hemnorrhage.  Unconsciousness. About fourteen ounces of the blood of' the husband
injected at six intervals. The patient's condition remained doubtful for some time, but terminated in recovery.
7th. By Ingleby. Uterine hlemorrhage after delivery. Patient
cold and insensible.  Injection of four ounces of blood firlnished
by the husband. After seven minutes the pulse reappeared.
After thirty minutes the patient was partially restored. Ultimate
recovery.
8th. By Dr. Klett. N'on-puerplral uterine hernorrhage. Cold
sweat, dimness of vision, hiccup, and an altered expression of face,
announcing the approach of death.  Injection of' blood furnished
by the husband.  The patient at once opened her eyes, and her
countenance changed for the better, Reccvery.
9th. By Dr. Klett.  Uterine hlemorrhage.  The patient, whose
aspect was cadaverous, took leave of her fiiends.  Articulation
imperfect. A small quantity of blood was injected from the husband. Life was reeistablished as if by the effect of electricity.
10th. By IMr. Lane. A young man subjected to the operation
for strabismus.  Obstinate hemorrhacge. Condition of the patient
desperate.  Three and a half ounces of blood injected fiom  a
young woman. Recovery.
11th. By M. Bougard. A female patient, exhausted by hamoptysis and subsequent abundant hemorrbhaoes. Injection of several
ounces of blood, furnished by a young woman. The patient lived
till the following year.
12th. By Dr. Savy. Uterine hnimorrhage in the third month of
pregnancy. Skin icy cold; eyes lustreless; lips pale; limbs relaxed.
Transfusion of blood, filrnished by a healthy servant. Recovery.




Vivisection.                        25
13th. By Nelaton. In this case the result was finally unsuccessful, as the patient died of puerperal complications; but the first
effect of the operation was as satisfactory as possible.
14th. By Domene.  Hemorrihage after delivery.  Signs of
approaching death.  Transfusion of' blood fiom a woman.  Consciousness returned a few. minutes after the operation.  Recovery.
Two successful cases of transfusion are also recorded in the
British and Foreig'n Medico-Chirurgical Review for July, 1857:
one by the late Professor Brainard, of Chicago, in the C/ticcgo
MIedical Joirn'hal fbr February, 1860; and one in the New Yor/D
Mecdical Joitrnal for November of the present year.
In these cases, as noticed by Berard, there is no doubt that the
operation saves the life of the patient; for in animals reduced by
hemorrhacre to the condition of apparent death, recovery never
takes place unless transfusion be perfcrmed.*
IV. Next, Artlftcial -Respiration.  There can be no need to do
more than allude to the usefulness of this operation, which has so
often been successful in cases of suspended animation.  It is intimately associated with the nature and mechanism of natural respiration, and these two elements of the finction were naturally
studied, to a great extent, together.  In the middle of the sixteenth century Vesalius had found that by blowing up the lungs
with air, after the chest was opened, the stoppage of the heart's
action might be delayed for a short time.  But the first attempt
at continuing life indefinitely in this way was that of Robert
Hook in 1664, who showed that: by alternately inflating the lungs
with bellows, and then allowing them to collapse, an artificial iespiration miglht be established which could be kept up for a long
period.  Hook reported this result to the Royal Society, where it
attracted all the attention which its importance deserved.
"'I did, therefore,"  he says, in a second comlmunication,t
" heretofore give this Illuestriouts Society an account of an Experiment I formerly tryed of keeping a Dog alive after his T/toracz
was all displayed by the cutting away of the Ribs and DiaphAragme, and after the Periccardiurn of the Heart was also taken off.
But divers persons seeming to doubt of the certainty of the Experiment (by reason that some Tryals of this matter, made by some
other hands, failed of success), I caused at the last IMeeting the
same Experiment to be shown in the presence of this l.oble (om2pany, and that with the samle success as it had been made by me
at first."
But this was not sufficient. Plain as the matter seems to us
now, it was nottllen certainly known in what manner the continuance of respiration maintained the circulation of the blood; and
by some this was thought to be accomplished not through the
* Coers de Physiologie. Vol. IIT., p. 222.
f Philosophical Transactions. Vol. 1I, p. 539.




26                         Vivisection.
chemical influence of the atmospheric air, but by the physical
movement of the parts.  To settle this point Hook contrived anothei experiment.  Having opened the chest as before, and fitted
his bellows to the trachea, he thon fitted a second pail of bellows
to the flurther end of the first, and at the same time made numerous incisions over the outel surface of the lungs. He thenr worked
the second pair of bellows very rapidly, " by which," he says,
6' the first pair was always kept full and always blowing into the
luncs,"  the lungs being thlemselves always full and without motion,
but having a constant blast of air passing through them.  Life
was sustained in this experiment as in the other.  Hook therefore
showed,
1st. That life might be indefinitely prolonged by the alternate
inflation and collapse of the lungs in artificial rlespiration; and
2d. That this was accomplished, not by the simple motion of
the parts, but by the continual introduction of fresh air into the
respiratory passages.
Artificial respiration was subsequently employed by Brodie,
Hope, Legoallois, Wilson Philip, and others, both for studying the
action of t he heart and blood-vessels, and for resuscitating asphyxiated animals.  It was also applied to the human subject, and is
now a recognised means of preserving life in cases of' drowning,
hangling, asphyxia fiom  breathing noxious gases, and the suspended animation of the newly born.
V. -Digestion.-There is a curious fact in the physiological history of digestion, viz. that the first source of definite knowledge
on this sulbject consisted  of experiments performed, not uplon
animals, but upon a man.  Alexis St. Martin, who was accidentally shlot in 1822, in such a way as to produce a gastric fistula,
enabled  Dr. Beaunlont to rmalke a series of observations which
were attended with valuable results.  Dr. Beaumont then positively demonstrated:
Ist. That the stomach secretes a peculiar acid fluid, which is
known as the gastric juice.
2d. That the gastric juice is secreted only during digestion and
when the stomach is excited; and
3d. That it has the power of dissolving the ingredients of the
food, and is accordingly a true digestive secretion.
But we cannot always have a man with a gastric fistula to
experiment with; still less make one in the human subject at will.
Accordingly the subject has since been studied by means of fistulse artificially established on animals.  I need not recall all the
discoveries which have been made in this way by Blondlot,
Sehwann, Bernard, Lehmann, and others.  I would only mention
two important considerations: First, that these subsequent labors
have fully confirmed the principal facts discovered by Beaumont,
and have shown that the propelties of the gastric juice are essentially the same in man and animals; and, secondly, that by them




Vivisection.                         27
our knowledge of the subject has been greatly extended, and
some of Dr. Beaumont's errors-unavoidable for a first experimenter in a-new field-have been explained and corrected.  Our
knowledge of the remainder of the digestive fluids, the pancreatic and intestinal juices, and the bile, as well as the sugar-producing function of the liver, has been almost entirely due to experiments on the lower animals.
VI. The Nervous System. —The study of the nervous system
seems to have been lnore difficult than that of the other great
divisions of the animal organism.  This is probably because the
functions of the nerves and nervous centres are so different in
their nature fiom the physical and chemical phenomena of nutrition, that they require, in most instances, peculiar methods of
investigation, not adapted to the study of the latter.  It is also,
no doubt, partially owing to the fact that the intricate structure
of the nervous system  requires a longer study of its anatomy
before that of its functions can be successfully pursued.  However this may be, it is certain that the mnore important discoveries
in this department date firom  a later period than thle others.
Galen discovered, by experiments upon living animals, the fiunctions of the recurrent laryngeal ner'ves, as connected with the
voice.  But fiom  his time the labors of investigators were principally confined to unravelling the anatomy of the nervous system,
until the early part of the present century.  The first important
advance was made at that time by the discovery that the endowments of sensation and motion occupy distinct localities in the
organs of the nervous system.
The exact history of this discovery has been open to some dispute, owing mostly to the fact that the ideas of physiologists on
this point were developed somewhat slowly, and only gradually
assumed the definite and precise form whichl they now present.
The main part of the discovery has been claimed principally for
two  experimenters, viz. Sir Charles Bell in England and Magendie in France.  The share which each really had in accomplishing this result is as fbllows:
Sir Charles Bell's investigations were guided by an idea, based
upon anatomy, that the different nervous tracts, connected with
different parts of the briain, had different endowments.  He considered the cerebrun  as connected with the anterior columns of the
spinal cord and the anterior roots of the spinal nerves, and the cerebellum as connected with the posterior columns and the posterior
roots.  His first experiments, in 1811, on the'spinal cord and
nerves, vwere undertaken for the purpose of ascertaining, through
them, the distinct endowments of the cerebrum and cerebellum.*
*tBell. Nervous System of the Human Body, 3d edition, London, 1844 p. 24;
also,'An Idea of a New Anatomy of tile Brain;" quoted in a Narrative of tlhe Discoveries of Sir Charles Bell in the Nervous System, by Alexander Shaw. Lorn
don, 1839; p. 40,




28                         Vivisection.
These experiments consisted in laying open the spinal canal of the
rabbit and irritating alternately the different columns of the cord
and the different roots of the nerves.   He found by this means
that irritation of the anterior colunms and roots produced convulsion of the muscles; while irritation of the posterior columns
and roots had no such effect.*  These experiments were performed, first, upon the uninjured animal, and  subsequently upon
those which had been stunned by a blow on the head.t  They
showed simply that the power of motion resided in the anterior
roots of the spinal nerves, but not in the posterior roots; and
consequently that the nervous roots, as well as the columns of the
cord, were dissimilar to each other. It did not then appear where
the power of sensation was located; nor what was in reality the
function of the posterior roots.t  This was necessarily left in
doubt; since, in all but the first of these experiments, sensibility
had been destroyed before opening the spinal canal.
The next and most successful experiments of Sir Charles Bell
were those performed, in the living animal, on the nerves of the
face.  They were communicated to the Royal Society of London
in  1821.~  These were  certainly the first experiments which
showed the important fact that the Seventh cranial neive is a
nerve of motion, while the sensibility of the parts resides in the
Fifth pair.  But even here, Bell's idea was not that of the simple
distinction of sensation and motion in these two nerves.  His
object was to show the existence of a great system of ]Resiliratory Nrcves, separate from  those of sensibility and voluntary
motion.  I-e regarded the Seventh pair as the great Respiratory
nerve of the face, and proved that when it is divided in the living
animal, the respiratory movements of the lips, nostrils, and cheeks
are abolished, while sensation remains.  But he still regarded the
Fifth pail as a nerve of' sensation and voluntary motion for the
whole face; the Seventh being simply superadded, to provide for
the movements connected with respiration.  It is impossible to
read his original paper, in the Philosophical Transactions for 1821,
without being convinced of this fact.
Nevertheless, this discovery was a very important one, and led
to important practical results.  For, before that time, surgeons
were in the habit of cutting the Seventh nerve for the cure of
facial neuralgia —of course,  with very unf:avorable results, as the
operation not only failed to relieve the neuralgia, but also produced a paralysis of motion in the face.  But after Sir Charles'Bell had shown that the Seventh was only a nerve of motion,
while sensibility resided in the Fifth pair, the old operation was
abandoned, and accordingly it is now the Fifth pair only which is
divided for the relief of tic douloureux.
* Narrative of the Discoveries of Sir Charles Bell, &c., p. 410
f Ibid. p. 87.     t Ibid. p. 46.
~ Philosophical Transactions, Vol. XXXI., p. 398.




Vivisection.                       29
In 1822 the study of the spinal nerves was taken tlp by Magendie, and the separate endowments of the two roots fully estalished. In order to exhibit the exact and valuable character of
these experiments, and to show how little they deserve the violent criticism which has sometimes been made upon them, I will
quote the original report by Magendie, in the Jozvnal cde PhEysiologie ]E'pe'rime;ntale et Pcttaologique, Vol. II. (1822); p. 276:
"For a long time," he says, "6 I was desirous of doing an experiment upon an animal in which I should divide the posterior roots
of the spinal nerves.  I had several times made the attempt, but
failed, in consequence of the difficulty of opening the spinal canal
without wounding the cord, and either destroying the animal or
inflicting upon him a serious injury. T But in the course of the
last month there came into my possession a litter of eight pups,
only six weeks old; and I thought this a good opportunity of
renewilg my attempt to open the spinal canal.  The result was
that I was enabled, by the aid of a sharp cutting scalpel, to
uncover, nearly at a single stroke,* the posterior half of the
spinal cord, still enveloped by its membranes. The only thing
then remaining to expose almost completely the surface of the
cord, was to cut through the clarac  mater surrounding it. This
was accomplished Nwithout difficulty, and I then had under my
eyes the posterior roots of the lumbar and sacral nerves. After
taking up these roots, one after the other, with the blade of a fine
pair of scissors, I divided them  on one side, the cord remaining
untouched.  I was uncertain what would be the result of this
operation.  Accordingly I sewed up the wound in the integuments and kept watch upon the animal.  At first I thought that
the limb corresponding to the divided nerves was entirely paralysed. It was insensible to pricks with a pointed instrument and
to the strongest pressure, and it also appeared to be motionless.
In a few moments, however, to my great surprise, I saw it move
very distinctly, thoiugh sensibility had altogether disappeared in
it. A second and a third experiment gave precisely the same
result; and I began to regard it as probable that the posterior
rloots of the spinal nerves might, indeed, be different in function
from the anterior roots, and that they might be more particularly
devoted to sensibility.
"It very naturally occurired to me also to cut the anterior roots,
leaving the posterior untouched.  But suchl an enterprise was
more easily conceived than executed; for how could the anterior part of the cord  be  laid bare without injuring  the
posterior ioots of the nerves?  At first, the undertaking appeared to be hopeless; but, after thinking the matter over for
forty-eight hours, I determined to make the attempt to pass in
fi-ont of the posterior roots, a kind of cataract-knife, with a very
narrow blade, so that I mlight cut the nervous roots by pressing
* Owing to the cartilaginous condition of the vertebrme in young animals.




30                         Vivisection.
the edge of the knife against the posterior surface of the bodies of
the vertebrre.  I was obliged, however, to give up this plan, on
account of the large veins which occupy that part of the spinal
canal, and which I wounded at each attempt to carry the knife
forward.  Blut in makin-g these trials, I noticed that, by drawing
aside the dura matelr, I could catch a glimpse of the anterior
roots, united in bundles, just at the spot where they penetrate
the membrane.  This was all that I desired, and in a tbw seconds
I had divided all the anterior roots upon which I Nwished to operate.  As in the previous experiments, I made the division on one
side only, that I might use the other as a term of comparison. It
may easily be imagined  with what curiosity I watched the
effects of this operation.  The result was unequivocal.  The limb
was completely motionless and relaxed, while at the same time it
retained a perfectly evident sensibility.  Finally, that nothing
might be neglected, I divided at once the anterior and posterior
roots. This produced entire loss both of sensibility anid movement.
" I have repeated these experilments in various ways, in several
species of animals; and the results above described were confirmed
in the most completO nzanner, both for the anterior and posterior
limbs. I am still continuing  these researches, of which I shall give
a more detailed account in a succeeding number.  For the present, it is sufficient that I can state positively that the anterior and
posterior roots of the spinal nerves have different fiunctions; and
that the posterior appear more particularly devoted to senlsibility,
while the anterior are more especially connected with the power
of nmotion."
In this way was the distinction of sensibility and motion in the
spinal nerves finally established.
It is a little remarkable, in this respect, that Sir Charles Bell
should be sometimes quoted as speaking in condemnation of this
kind of experiment; for whenever he does so, he appears as a witness against himself.  In reviewing, at the present day, the works
of Sir Charles Bell and their results, it is evident that everything
of value in the physiology of the nervous systein whichl he discovered, viz. the motor character of the anterior roots, and the
distinction between the fifth and seventh cranial nerves, lie discovered by means of experiment upon living anima's.  Thlese
discoveries were positive and permanent, and retaini at this day
their full value.  But all Sir Charles Bell's theoretical views,
which lie thought of so much importance, such as the division of
the nerves into reqzcar and ir'regcglctr or sulpercatcted, and the great
respiratory system of nerves, arle now destitute of interest, and have
nearly passed out of mind.
There is one circumstance connected with the discovery of
the distinct properties of' the spinal roots, which is so curious in some respects that it has beconme a kind of joke in
the history of physiology.  At quite an early period, in 1809,




Vivisection.                        3 1
Alexander Walker conceived the idea, on certain theoretical
grounds, that the  anterior spinal roots were nerves of sensation, and the posterior roots the nerves of motion.  HTe -was
thoroughly convinced of the truth of this doctrine;so much so,
that twenty-five years later he published a work entitled'"The
Nervous System, Anatolmical and Physiological,"' in which he
reiterated his viewvs, and maintained that Sir Chiarles Bell and
Magendie were entirely wrong. In vindicating his claims in this
work, he says (page 136):'c In 1809, viz. twenty-five years ago, the writer published the
true doctrine of the nervous system; a., ascribing sensation and
action to distinct nerves and columns; b., ascribing  these truly,
viz. sensation to the anterior and action to the posterior nerves
and columnns."
Also (page 137), "In 1815, viz. six years after his first publication of this doctrine, the writer repeated  and extended it, in
hormpson's Annals of Philosophy, still ascribing sensation and
action to distinct nerves and columns, -and ascribing these truly,
viz. sensation to the anterior and action to the posterior nerves
and columns."
Also (page 138), " Thus the title, to wlhich either Sir Charles
Bell or M. MIagendie have presumed to lay claim, viz. the ascribing distinct functions to distinct nerves and columns (and ascribing these wrongly, as the wiiter has shown), dates twelve or
thirteen years after this was done (and done rightly) by the present writel.."
Now, Alexander Walker had a very bad opinion of experiments, especially when performed upon the nervous system, to
which, le thinks, they are "'totally inapplicable.'"*  He has a
paragraph on page 97, headed:
6Ultter TVorthltessness of all _Experiiments on Living Animals,
in which.Functions are clestroyed or distunrbecd."
In the course of this paragraph he remarks (page 105), "The
rage for experiments on living animals will now  be easily understood. All fools have eyes and fingers.  They rejoice that some
fantastic use of these may he called experiment.  This becomes a
happy compensation for the want of reasoning powers.  The number of pretenders naturally renders the method universal; and
each blockhead thinks himself wise when he has nmade an experiment which he does not understand.  Henceforth," he says, " let
these men know that amplitude of eye and hand is a wretched
substitute for littleness of brain, and that reasoning powers are
essential to all advances in physiology."
In a previous paragraph (page 11) the writer siys that, where
*-The Nervous System, Anatomical and Physiological.  By Alxander
Walker. London: 1834, p. 105.




32                       Vivivsection.
we are dealing with living and complicated functions, "the performance of experiment is the act of a person who has not the
slightest notion of the use and application of experiment, and it
becomes the mere play of a driveller or an idiot. Of this," he
adds, somewhat innocently, "6 the reader will have a striking illustration in the sequel."'
From his description of certain experiments, however, it must
be confessed that Walker does not seem to have had any practical acquaintance with them.
Subsequently to 1822, other discoveries of great interest in the
nervous system have been made: by Longet, Magendie, and 1ernard, on Recurrent Sensibility; by Mayo and Marshall Hall, on
Reflex Action; by Schiff, Vulpian, and Philipeaux, on the Regeneration of Nerves; by Legallois and Flourens, on the Properties of
the Medulla Oblongata; and by Brown-Sequard, on the Crossed
Action of the Spinal Cord;-all by means of experiments on living
animals.
VII. Experiments of this kind formed a large part of the discovery, by John Hunter, of the modern Operationfor Aneurismn
Previously to 1785, the best treatment for this affection consisted
in opening the aneurism and tying the vessel in the wound, or in
applying a ligature immediately above and below the part. This
operation, however, was usually unsuccessful, owing to fatal
secondary hemmorrhages fiom the aneurismal tumor, or firom the
ligatured part of the vessel. The manner in which the improvement in treatment took place was as follows:
6" Mr. Hunter,* from  considering the manner in which the
spontaneous cure of external aneurisms was effected, was led to
propose and practise, in the year 1785. the operation which justly
bears his name..    The only point on which he required
information was, whether the repeated h-morrhages which took
place (when the ligature was placed immediately above the aneurism) were really in consequence of the artery being diseased;
and this he endeavored to elucidate by observation and experiment.  Hie laid bare the inner coat of an artery (in the dog) by
dissecting off by layers the two outer ones until he saw the blood
through the remaining   ernmbrane; the wound was then closed,
and the animal was killed three weeks afterward, when the parts
were found consolidated, the canal of the artery being neither increased nor diminished. This was not supposed to be sufficient
to establish the fact that an injury of this kind might be inflicted
on a sound artery with impunity; and Sir Everard Home, after
dissecting off the outer and middle coats, in a similar manner,
laid a piece of lint upon the artery, to prevent adhesion, instead
of closing the wound. It healed tp at the end of six weeks,
when the dog was killed, and the artery being injected, the coats
of it were found of their natural thickness and appearance.
* Guthrie, on the Diseases and Injuries of Arteries, London, 1830, p, 148.




Vivisection.                      33
6Satisfied by the result of these experiments that ulceration of
the artery depended more on its being previously diseased than on
the injury committed upon it, he fairly supposed that if he placed
his ligature higher up on the artery, on a sounder part, he would
have a better chance of avoiding the hemoorrhages which had so
fi equently proved fatal."
Experience afterward showed this operation to be successful, and
it has since been the means of saving many limbs and of preserving many lives which would have been sacrificed under the older
method of treatment.
VIIIT. There are few improvements in surgery which have been
attended with more satisfactory results than those which were introduced into the operations of resection and extirpation by the
discovery of the Ofce of the Periosteem in the Regeneration of
-Bone.  When a large portion of any bone requires to be removed,
on account of firacture or disease, the permanent deficiency of the
bony parts, after the healing of the wound, is a very serious inconvenience; so much so that surgeons were frequently in the
habit of amputating the entire limb rather than retain a member
which, if preserved, would be practically an incumbrance to the
patient instead of an advantage. The study of the mode of reparation of bone, by means of the periosteum, has shown how this
difficulty may be avoided, and how much advantage may be gained
in the preservation of injured and diseased parts.
Du Hamel, in 1'740,* and Hunter, in 1772,t first learned, by
experiments on pigeons, fowls, and young pigs, that the growth of
bone takes place mainly from the exterior, and probably by the
nutritive power of the periosteum.  Subsequently this question
was further examined experimentally by Flourens, Heine, 2Murray,
and others. Mr. Syme, of Edinburgh, in 1837,t endeavored to
ascertain, as he expresses it, "whether the periosteum, or membrane that covers the surface of the bone, possesses the power of
forming new osseous substance independently of any assistance
from the bone itself." Hle extirpated the middle portion of the
radius of a dog, with its periosteum, and found, as Sir Astley
Cooper had previously done, that after the recovery of the animal
there was no bony union of the parts, but only a ligamentous
band, running fiom one bony extremity to the other. At the
same tinle lie did a similar operation on the radius of the opposite
leg, only leaving the periosteum in its place; and on this side he
found, at the end of six weeks, instead of the gap presented by
the first, leg, " a compact mass of bone occupying the space left
by the portion removed." He also detached the periosteum in another dog without removing the bone, and inserted a piece of
* MIdmoires de l'Academie Royale des Sciences, 1741,'42, and'43.
F1 Works of John Hunter. Palmer's edition. London, 1835. Vol. IV., p.
315.
t Transactions of the Royal Society of Edinburgh. Vol. XIV., p. 158.
3




38~~~4 D                ~Vivisection.
metal under the membrane, in which, at the end of six weeks, he
found a thin plate of bone, entirely disconnected with the original
osseous surface.
Wagner, in a monograph on the Process of Reparcation cafter
_Resection ctncd ExtirI2a(tion of the _Bones,* points out the usefulness
of these experiments, and the reasons upon which their value depends.
"' The anatomical study of the process of reparation," he says,t
"may be made either on man or on animals.  It would be better, no doubt, to make this study upon man, but for this purpose
it would be necessary to have the opportunity of dissecting, at
different periods, human limbs which had been the subjects of resection. It would be necessary that the patient should die, or
that secondary amputation should be performed; and, judging
firom the poverty of our knowledge in this respect, it seems probable that such opportunities are only rarely met with. If so, this
would go to prove the safety of the operation of resection. It is
true that it is still more rare to have the opportunity of dissecting
the body of a person who has before been the subject of resection,
and who has survived a certain time after the completion of the
cure.
"We must, therefore, have recourse to experiments on animals,
and by this means we may follow all the steps of the reparative
process."
Wagner's experiments, which were mainly performed with
dogs and pigeons, carried still further our knowledge of the process of reparation and the part taken in it by the periosteum.
But the most recent and extended investigations on this subject
were those of Leopold Ollier, in 1858.4  He operated by separating, in the living animal, a lamina of periosteum fiom the surface
of the tibia and transplanting it among the neighboring muscles.
He found that the periosteum, thus removed from its original locality, not only continued to live, but produced bony tissue in its
new and unaccustomed situation. This happened even when the
lamina of periosteum was entirely separated from its original attachments and transplanted, like the skin in autoplastic operations
on the face. It took place even when the separated periosteum
was transplanted into distant regions, as into the popliteal space,
or under the skin of the groin or that of the back. In all these
cases, the new bone produced had the natural structure of osseous
tissue, as shown by microscopic examination.
Oilier also practised resections and extirpations of the long
bones, making always a comparative experiment in order to judge
of the influence of different modes of operating. He extirpated
the radius and metatarsal bones, upon rabbits and dogs, taking
* In Archives Generales de Medecine (1853), Vol. II., p. 712.
Ibid, p. 713.:Recherches Experimentales sur la Production Artificielle des Os, &e. Journal
de la Plysiologie de l'HoImme et des Animaux. Janvier, 1859.




Vivisection.                         35
away also the periosteumra in some instances, and in others leaving
it undisturbed.  He found that when the periostenum was left, a
new bone was developed in from one to three months afterwardl;
but when it was removed,  no bony regeneration took place.  In
extending his observations to cases of resection of the joints, 01lier found that when the articulating extremities of the bone were
removed, with the periosteum and articular capsule, the new joint
formed was simply a solid fibrous band uniting the divided extremlities of the bone; but when the periosteum and articular capsule were left, the articulating extremities of the bones were regenerated in their natural form, and a true articulation, with a
more or less complete synovial cavity, formed between them.
The practical importance of these results, for patients suffering
from injuries or diseases of the bones, requires no discussion.  It
has been fully appreciated by surgical practitioners at the present
day.
IX. In 1861, Dr. S. WVeir Miitchell, of Philadelphia, published
the results of two years' researches on the Venom of the _allttesnacke, and the TTreatment of Ravttlesnake-bites.*  In these researlcies Dr. Mitchell investigated the anatomy of the fangs,
poison-glands, and accessory parts, in the rattlesnake; the mode
of production and discharge of the poison, its composition and
properties, its action on var'ious species and classes of animals, and
the value of different remedies and antidotes.  For this purpose
he kept several of the living snakes constantly under his observation, and by repeated personal inspection and manipulation familiarized himself with their habits and physiological peculiarities
from every point of view.  He performed seventy-three experiments with these animals, and observed the action of their poison
on fi'ogs, serpents, reed-birds, pigeons, dogs, and rabbits.
The papel', in which the account of these experiments is given,
has no superior in medical literature for the clearness and elegance
of its style, the abundance of its material, and the precision of its
results.  It illustrates very distinctly the value of strictly elementary researches as a necessary preliminary to those of a more
practical nature,
"' When I first," as the author remarks,t "' engaged in the study
of the venom of the rattlesnake, it was with the intention of ascertainincg what value Bibron's antidote possessed.  To effect this
single end I procured four or five snakes, and proceeded to subject animals to their fangs, and afterward to give the supposed
antidote.
"'After destroying many animals and attaining only negative
* Smithsonian Contributions to Knowledge. Researches on the Venom of the
Rattlesnake, by S. Weir Mitchell, M.D., Washington, 1861; and an article on the
Treatment of Rattlesnake-bites, in the North American Medico-Chirurgical Review, Vol. V., p. 270.
t N. A. Med.-Chirur. Review, Vol. V., p. 270.




36                        Vivisection.
results, I began to perceive that I was working in the dark, and
that it was altogether impossible to obtain useful results, without
possessing definite knowledge as to the nature of the venom, the
mode of its formation and ejection, and the whole natural history
of the disease to which it, gives rise."'
It would be difficult to find a medical treatise which should
illustrate more fully than this the judicious caution and reserve
which guide the physiological experimenter, and which enable
him to avoid the sources of error that lie in his way. The constant employment of comparative and counter-experiments, and
the frequent variation of the methods employed, indicate the care
and faithfulness of the investigations, and inspire a well grounded
confidence in their results.
In the study of antidotes and remedies, Dr. Mitchell shows the
existence and origin of two classes of fallacies, which have heretofore vitiated much of our knowledge on this subject.
First, _Fallacies carising from want of exact kn7owlecdge as to the
secretion of ve)tnomq, and the mode in wZhich the serpent uses its
fangs andc ejects the poison.
Second, Flallacies carising fromn want of information in regard
to the natu-rcal history of the disease caused by the venom of serpents.
Finally, the paper shows the comparative value of the various
antidotes in vogue; the usefulness of the " intermittent ligature,"
in checking and controlling the entrance of the venom into the
circulation; and the true metl-hod of employing stimulus to sustain
the patient and preserve him fiom the fatal effects of the poison.
X. I shall refer in detail to only one more instance of the usefulness of these experiments, viz., the origin and prevention of
Parasitic D)iseases. There are certain parasites which infest the
human body, some of which are exceedingly troublesome, and
others often fatal.  One of these is the tapeworm.  The tapeworm, as we know, is derived from eating pork which i's infested
with another parasite, viz. cysticercus.  But the eysticercus is
so different fiorn the tapeworm in size, structure, and appearance,
that no connexion was formerly supposed to exist between them.
The identity of the two was discovered in Germany about the
year 1845-50, by Siebold and Kiichenrneister.*  By experimenting upon mice, rabbits, dogs, and cats, these naturalists found that
certain species of cysticercus and tmenia were identical with each
other,. and that a cysticercus in the flesh of one animal, when eaten
by another, became developed into a tapeworm in the intestine of
the second, This discovery led, soon afterward, to the important
result that the human tapeworm  is derived ftom the cysticercus
of the pig; and showed the way in which infection by this parasite may be avoided in the human species.
* Transactions of the Silesian Association for National Instruction, Scientific
Department. Session of July 7th, 1852.




rVivisection.                     37
A more recent and striking instance of the same kind is that
of the trichina spiralis. This worm has been known, since 1832,
as infesting, sometimes in large numbers, the voluntary muscles
of the human subject. It was found on many occasions in dissecting-room subjects and in hospital patients, and was examined
by Owen, IHenle, Bischoff, Luschka, Harrison, and Farre.  But
in these cases there was no evidence of the patient having suffered anything from the presence of the worms; and, notwithstanding their great numbers, it was the universal opinion of the
profession that the trichina spiralis was a harmless parasite in the
human muscle. Nothing was known of its origin or mode of development.
But a little over ten years ago, certain physiologists in Europe
began to experiment with these parasites, and, by administering
flesh infected with trichina to pigs, dogs, and rabbits, they found
that the worm became further developed in the intestine of these
animals, and that it there began to acquire a perfect sexual organization.  In 1859, Professor Leuckart, in Giessen,* continued
the experiments, and showed this development to be complete;
the muscles of the second animal becoming infested with the
progeny of the trichina, which he had swallowed with his food.
This was the state of our knowledge when, in the year 1860,
the members of a family in Dresden were taken ill with symptoms
of intestinal irritation, fever, and general pains. One of them, a
servant girl, died; and, at the autopsy, her muscles were found
to be fiill of trichina spiralis.  These infected muscles were examined by Dr. Zenker and Professor Virchoff, who administered a
portion of them to a healthy rabbit. This animal died at the end
of a month, and was found to be also infected with trichina.  A
part of his flesh was given to a second rabbit, who also died, infected, four or five weeks later. The flesh of the second rabbit
was then given to a third, who became infected in the same way,
and also died at the end of a month. In the meantime, inquiries
had been made at Dresden, and a part of the pork, which had
been served as food to the family shortly before they were taken
ill, was examined, and found to be infested with trichina.
By these investigations, the medical profession became aware
of the existence of a fatal and heretofore unknown disease, and at
the same time were made acquainted with its source and the manner of its production. Undoubtedly, many cases of trichinosis
had happened before 1860; but they were not understood, and
the patient was supposed to be laboring under some form of fever
or rheumatism.  WYe now know that the trichina, when first introduced into the system, creates a violent disturbance by irritation of' the intestine, and by penetrating the tissue of the voluntary
muscles. It is often fatal in this stage; but if the patient survive
the first five or six weeks, the parasites become encysted in the
* Untersuchungen iiber Trichina spiralis. Leipzig, 1860.




38                         Vivisection.
muscular flesh, and remain there, quiescent and comparatively
harmless, for an indefinite period.  It was these old and encysted
specimens which were filrst observed, and which could not be referred to any previous illness.
Other experimllents have since shown how trichinosis may be
detected in polrk and wvhat precautions are necessary to prevent
infection firom pork used as food.
The importance of this subject may be further estimated from
two facts: First, that since 1860 several epidemics of trichinosis
have happened in Germany, in two  of which over five hundred persons were affected, of whom  one hundred and twenty
died;* alnd secondly, that pork in this country is also subject to
trichinosis, as appears by the report of a committee of the Academy of Sciences, of Chicago, published in the Chicago Daily
Republican of April 13, 1806.  This committee examined the
flesh of 1,394 hogs brought to Chicago, and found twenty-eight
of the nunmber, or one in fifty, infected with trichina.  Cases of
fatal poisoning firom this cause in the human  subject lhave also
happened in this country, two of which have fallen under my own
observation.
It is to experiment upon living animals, therefore, that we owe
our knowledge of this new and dangerous disease, always liable
to present itself to the medical practitioner.
In conclusion, there is one point to which I would allude, which
seems to rme of decisive importance.  It is sometimes asserted by
those who oppose pliysiological experiment, that there are other
sources of information miore legitimate and allowable, and that
the chief of these is the observation of the phenomena of disease
met with in the treatment of the sick. But do those who take
this ground appreciate what they really inculcate when they recommendc that we should rely upon this source of knowledge,
and neglect experimentation?  Do they overlook the fact that
such a course is simply wcaiting for acccicYentcl enxperiments to help
us in our inquiries?  What was the case of Alexis St. Martin but
an experiment, accidentally arranged, by a gunshot wound?
When we arle called to a case of disease, we do not wish to muanipulate and experiment with it; we wish to cure it. In order to
cure it, we must know its pathology, and understand it beforehand.  And if we do not so understand it, then our observations
and manipulations in that case are experiments oin the living man,
and cannot be regarded as anything else. Take the case of the
Facial nerve and the Fifth pair.  Sir Charles Bell himself says t
that, previously to his time, as the result of operations on the
face for tiG douloureux, "' after fifty years of experience, wre remained ignorant of the distinction in these nerves."
* Epidemics of Hedersleben and Quedlimburg. L, A Gosse; Des Trichines
spirales, Geneve, 1866, p. 30.
f Nervous System of the Human Body, p. 77.




Vivisection.                       39
It is true that, in many instances, our observations in disease,
and our attempts for its' cure, must necessarily be of the nature
of experiments upon man.  But when experiments upon animals have led the way, and have cleared up, in advance, some of
the important points in physiology or pathology, they can only
be regacrded as fortunate and precious aids in our study, of
disease. The assistance which this method of investigation may
be to us in the future can be judged of by what it has done
in the past; for the science of' Medicine is one which is constantly advancing, as each generation receives the benefits and
feels the impulse communicated by its predecessor.
I have enumerated above the more striking improvements in
our knowledge  due to  physiological experiment, and those
most directly productive of practical results.  Every medical
man, however, will comprehend that these form but a small proportion of the acquisitions which we really owe to it. An immense
number of details in every department of physiology have also
been learned fiom this source, which were not directly connected
with any especial practical point in medicine or surgery.  But
they have none the less served to enlarge and complete our physiological knowvledge, and to bring it, in numberless minor particulars, into harmony with the truth. And there can be no
doubt that the greatest value of physiology, as connected with
medical and surgical practice, is the influence which it exerts in
a general and intangible way; —by making the practitioner acquainted  with the natural functions of the animal organs, and
their variations within physiological limits, so that he is enabled
to study, with a more intelligent motive and a clearer conception,
the processes and phenomena of disease. It is this reasonable
and more intelligent method of study which distinguishes the
science of MJledicine, as a whole, at the present day, and which
will undoubtedly be productive of equal improvement in the future.
The benefits of a physiological discovery, accordingly, are not
confined to the particular point with which it is especially connected; but it reacts on other similar questions, and raises new
points of inquiry, or reconciles previous discrepancies; and its
greatest advantagae is, after all, that it enlarges, in a general way,
the boundaries of physiological knowledge. If I have confined
myself, therefore, in the foregoing pages, mainly to instances in
which experiment has led directly to practical results, it is because the value of' such instances may be more easily and rapidly
comprehended, and may be presented with greater preciseness
and detail; and because they show, in a clear light, one aspect of
the importance of physiological studies, and the means by which
they are successfully pursued. If' it had not been for experi-ments on living animals we should, at this day, be ignorant of the
circulation of the blood; ignorant of the nature and mechanism
of respiration; of the properties and functions of the nervous




40                        Vivisection.
system; of the operation of transfusion; of artificial respiration; of the origin and pathology of parasitic diseases; of the
best treatment for serpent bites and other venomous wounds;
of the office of the periosteum in the regeneration of bone;-perhaps of the Hunterian operation for aneurism; and, for all tehat
appears to the contrary, we should still be cutting the seventh
pair of nerves for the cure of tic douloureux.
I have thus endeavored to indicate some of the principal benefits which have resulted to scientific and practical medicine from
this mode of investigation; and to place it, both in regard to its
objects, its methods, and its results, in the position to which it is
entitled, as an invaluable assistant to the medical art.