Contributions to Physiology. By Bennet Dowler, M. D., of
New Orleans.
This is the third of the ‘ Contributions to Physiology,’ which the
ingenious and able author has communicated to the New Orleans
Medical Journal. Of his ingenuity, ample evidence is afforded in
his well devised and well executed experiments, and in many of
the arguments he brings forward to combat the views of others.
Of his ability no less evidence is presented ; for although we may
be, and are, disposed to question certain of his conclusions, we are
ready to admit that they are well and cogently enforced. We
would prefer, that the style in w’hich they are frequently put forth
was somewhat modified. To our taste it is too turgid, too epi-
grammatic, and at times too quaint; but this is a matter of taste,
on which, as on tastes in general, it would be proverbially idle
to dispute.
“ The experimental researches now offered to the reader’s attention,
originated incidentally, during a course of anatomical examinations
made upon the great saurian of Louisiana ; examinations which have
corrected numerous prevalent errors, and which have at the same time
resulted in discoveries that are deemed important, if not fundamental,
in their bearings upon the doctrines of philosophy; none of which,
however, are essential to the purposes of this paper, and, therefore,
need not be given now. For anatomical, rather than for physiological
reasons, my vivisectionshave been chiefly confined to the alligator; an
animal whose anatomy, physiology, and psychology place it above
frogs, turtles, and salamanders, which have been generally relied on
by experimenters. How unlike soever the alligator is to man, these
latter are more so. If frogs are good, alligators are better. Indeed,
Dr. Carpenter, a distinguished physiologist, expressly declares that
£ experiments on the nature of this (the nervous) function, are best
made upon the cold-blooded animals; as their general functions are
less disturbed by the effects of severe injuries of the nervous system
than those of birds and mammals.’ ”
The history of the experiments of Dr. Dowler, on “ the great
saurian of Louisiana ” are exceedingly interesting, they would be
esteemed miraculous had we not long known the astounding pheno-
mena presented by the amphibia, and by many of the lower classes
of animals. It is familiar to every one that the frog will continue
sitting apparently unconcerned for hours after it has been evisce-
rated ; that the tortoise will walk about for a long time after de-
capitation ; that the divided portions of a polype will form so
many distinct animals ;. that a common land tortoise, whose brain
had been removed, has continued to walk about for nearly six
months, groping its way forward for want of vision. The inde-
pendence of the parts of a wasp, when the head has been separated
from the body, are familiar to all : the head will appear to at-
tempt to bite, and the tail to sting. The striking case of the rattle-
snake, recorded by Dr. Harlan, is known to every well read Natur-
forscher and physiologist. He cut off the head, and grasping the
part of the neck attached to the head with his finger and thumb,
the head twisted itself violently, endeavouring to strike him with
its fangs. A live rabbit was presented to the head, which imme-
diately plunged its fangs deep into the animal; and when the
tail was laid hold of, the headless neck was bent quickly round as
if to strike the experimenter.
It need scarcely be said, that the reflecting physiologist, whilst
he observes the phenomena in all classes of animals, must exert
due caution in his application, to man., of laws, which he may
consider himself justified in deducing from such phenomena ; and
caution is especially required when the observations are made on
animals like those experimented on by Dr. Dowler. If we place
a batrachian under the air-pump, and exclude the air as far as
practicable, we observe it apparently but little incommoded ; and
we know that such animals can exist for years imbedded in rocks;
whilst a sudden diminution of atmospheric density to one-half
will inevitably destroy all the higher animals. The phenomena,
consequently, observed and recorded by Dr. Dowler, are elucida-
tive of the biology of certain beings in the scale of animated crea-
tion, whilst they may fail in their application to others, and
especially to man ; and the same remark is applicable to the con-
clusions at which he arrives, after detailing his various experiments
on the alligator.
“ On the whole it may be safely concluded, that voluntary motion is
neither directly communicated from, nor regulated by the brain, or the
cerebellum; that the muscles, in connection with the spinal marrow,
perform voluntary motions for hours after having been severed from the
brain ; that these motions are not only entirely independent of the brain,
but may take place, though imperfectly, after the destruction of the
cord itself; that the trunk, as well as the brain, thinks, feels, and wills,
or displays psychological phenomena ; that the sensorium is not re-
stricted to a single point, but is diffused, though unequally, or in a
diminished degree, in the periphery of the body; and that actions
which take place after decapitation, as described above, are in absolute
contrast to reflex actions, being sensational, consentaneous, voluntary,
and in other respects, dissimilar.”—p. 342.
We give in his own words the satisfactory and suggestive de-
tail of his experiments.
Sept. Sth, 1849.—Experiments on the .Alligator.—Dr. S. Powell,
of this city, witnessed all, and aided in most of these experiments : this
account was written the same day, and was read to, and approved by
him.
li A longitudinal incision in the neck, from above, was made through
the thick mass of muscles upon the cervical vertebrae—the vertebra?
and the spinal cord were divided completely; the finger was passed
between the divided parts. In about three quarters of an hour after, a
traverse incision was made midway between the shoulders and hips—
the spine, with the cord, was divided with the saw, the parts were
separated so as to admit the finger between the divided ends of the
cord, exposing the abdominal cavity. In about half an hour after this
second division, the animal was placed on its back, and the whole of
the viscera were slowly dissected, and removed from the body. The
sympathetic was destroyed. This last dissection occupied about one
hour. During the latter part of this process, and some time after the
removal of the organs, the animal died, having lived after the first
section, about two and a half hours.
“ During a period of more than two hours, this animal displayed
complete intelligence, volition, and voluntary motion in all divisions
of the body. It saw, heard, felt, defended itself, showed anger, fear,
and even friendly attention to its keeper, a black boy. This latter
manifestation, is so extraordinary in an alligator, that 1 will notice it
first, though it was not verified, until after the second division of the
spinal cord. This animal, with several others, were presented to me,'
by my friend Dr. Young, when leaving this city, to visit Europe,during
the last summer. Mr. Barbot (at whose apothecary store this animal
had been kept, with the others, for many months) informed me, some
weeks ago, that it had become fond of the black boy, who had taken
care of it. The experiments had lasted more than an hour—the animal
had been much exhausted—had lost much blood, and, for a time, scarcely
seemed to take notice, when Mr. Barbot proposed to bring up to the
third story his servant, its keeper; the boy went near it—he called it
in a kind of gibberish style—it raised up its head and turning towards
him, gently opened its mouth—looked quietly at him without its usual
menace. All four of the gentlemen then present, agreed that it recog-
nized the boy, and that it manifested affection for him. The boy
repeated his fondling calls (gibberish) several times, and with the same
results. It saw him, followed him with its eyes, and knew his voice.
Its mute language could not be mistaken. It was the first time T had
seen- affection of this kind in alligators. I have kept some nearly a
year. They always feared, or menaced me, though I always fed them.
For nearly two hours, the animal watched our operations: on ap-
proaching too near it, so as to excite its fears, it raised its head, opened
its mouth to bite, directing its head to the right or left, to attack its
enemy. It threw the nictating membrane over the eye, on perceiving
a body approaching near the cornea, in order to defend the same ; and
this, too, in advance of actual contact. It retained the sense of hear-
ing: for on making a noise by striking aboard, without advancing
towards the head, it looked angry, and opened its mouth to bite.
“In the meantime, the other parts of the body (though its spinal
marrow was divided in two places,—in one severing most of the muscles
of the back) manifested sensation, volition, and combined or complex
motions of a vigorous character. This was not all. For, the lateral
muscles of the body not divided, together with the hind legs, were
adapted so as to aid the forelegs in removing fire, or a pricking body,
above the part divided. In fact, the forelegs, and hindlegs, mutually
aided each other, notwithstanding the intermediate division of the cord.
“After nearly two hours spent in this kind of experiment, it was
found on dissecting the viscera, and sympathetic, the animal lying on
its back, that it directed its limbs to the place where the knife was
applied in dissection.
“ The heart continued to act as long as it was observed, even after
having been roughly handled, emptied, and removed from the body.
“For want of suitable instruments to divide the spine, the vertebrae
were injured, and the muscles were extensively divided, which of
course, diminished the brilliancy of the results.
“ October 30th, 1817.—Experiments on an Alligator, nearly three
feet long; by Dr. Young, Mr. Barbot, and myself:—Five grains of
strychnine were dissolved—half of which was thrown into the gullet
—a small portion was regurgitated; in twenty-five minutes several
convulsive contractions took place in the general muscular system.—
The residue of the mixture was now given ;—a portion was again
rejected—the convulsive contractions increased—tetanic rigidity fol-
lowed—the jaws forcibly closed—the limbs became stiff and straight.
In one hour after taking the first portion of strychnine, the animal
appeared nearly dead—there was only an occasional motion on the
hind legs, tail, and in the nictating membrane. Dr. Young now began
to dissect the animal, with the view of preserving its head, and skin.
The limbs had ceased to be rigid, and were sometimes directed intelli-
gentially. The spinal cord was served in the neck,—a probe passed
down the spinal canal two or three inches below the part giving off the
axillary plexus, br-aking up the texture of the cord completely; one
spasmodic jerk followed in the forelegs, on introducing the probe. For
an hour after destroying the cord, the forelegs contracted, though far
less frequently, less forcibly, and less definitely, than the hind legsand
tail. The heart for three hours, that is, as long as observed, acted reg-
ularly, both before and after its removal from the body.
“ April 13th, 1848.—At 10 A. M.,I observed an alligator, in articulo
mortis, fits health had been declining for some days, owing to an in-
flammation of the bowels with ulceration, as the post mortem exami-
nation showed;) it was unable to walk, but watched my movements.
In fifteen minutes afterwards, it appeared to be quite dead. It was
placed on its back for dissection ; it moved its limbs intelligentially for
several minutes. The dissection lasted seven hours; during nearly half
of this time, the heart or ventricles continued to beat about fourteen
times per minute—the right auricle, about twice as often. The heart
was separated from all its annexiae, but did not cease to act, until after
its ventricles had been roughly probed. Thus freed from blood, and
removed from its connections with the nerves, it acted with regularity,
as before.
“May 12th, 1848.—Having observed that an alligator had become
feeble, I determined to kill it for dissection. On taking hold of it, it
seemed much alarmed, and cried several times, Houpe! Houpe ! This
is the only articulate sound that I have ever heard from an alligator,
and it is, I believe, peculiar to the young animal, and is never uttered
but when danger is suspected ; it appears to be the synonym of the word
Help, the sound of which, it very much resembles. It hissed, and
attempted to bite. The upper portion of the skull, including a hori-
zontal stratum of brain, was removed. Haemorrhage, to a considerable
extent, followed ; the eyes closed. The animal no longer attempted to
bite. It performed, however, a series of voluntary motions, intelli-
gently directed, to ward off injuries. The entire brain and the medulla
oblongata were removed, without diminishing its power to direct its
limbs to any part that was pained by the slightest touch of a pin or
knife. A metallic rod was passed many times within the spinal canal,
completely destroying the spinal marrow beyond the hips. The animal
appeared to die very soon, the tail excepted. It was, however, after-
wards found, that both voluntary motion, and sensation, remained,
though their manifestations were greatly impaired. The forelegs were
slowly and feebly directed towards irritated parts; these motions
disappeared in a very few minutes. The tail twitched frequently, for
an hour after, as if pained by the dissection of the trunk, and viscera.
Both before and after its removal from the body, the heart acted regu-
larly for four hours. The right auricle was the first to collapse.
“ May 22d, 1818.—Dr. Young, and myself, (aided by Mr. Barbot,)
performed the following experiments, upon a stout alligator, four feet
long. Two men drew several strong twines with all their strength
around the animal’s neck, but this, in ten minutes, did not produce
either strangulation, or palsy, though the force of the limbs was dimin-
ished. Decapitation was now performed. The great carotid, which
threw out blood freely, was tied after three or four ounces had been
lost.
K For more than an hour after decollation, sensation, perception,
vision, passion, and voluntary motion continued in the head. It saw
its enemies—opened its mouth to bite, at the proper time—nictated,
when a foreign body approached the eye. The pupils responded, natu-
rally, to the degrees of light.
“ The headless trunk for three or four hours, during extensive muti-
lations by two operations, manifested, in a still higher degree, sensa-
tion, intelligence, definite, well directed muscular actions. There was
as usual, a complete loss of progressive or forward motion. The tests
used to elicit sensation, and voluntary movements, were pinching,
puncturing, and burning. Its sensibility and motions appeared to be
nearly as acute, quick and varied, as in the unmutilated animal. The
direction of the limbs was not such as could be deemed habitual, as in
walking and swimming. Some of these motions are of difficult execu-
tion in the entire animal, from its anatomical conformation ; such as
reaching up between the shoulders or hips, to remove an irritant. All
of-the muscles that could in anywise contribute to the will and aims of
the animal, as in curving the body or tail, so as to bring the irritated,
part within the range of the appropriate limb, etc. There was not
a single unmeaning or convulsive motion. These motions, altogether
volitional, began, continued, and ended with the pain producing cause.
For hours, during the dissection of the visqera, the limbs, when un-
confined, were directed in the intellig'entiaf manner. While operating
on the organs connected with the sympathetic or ganglionic system,
these motions were less vigorous hnd^ess frequent, than those noticed
during operations on the periphery. It was necessary to tie the ani-
mal on its back, during the dissection, to restrain its intelligential mo-
tions.
£‘ The heart remained in situ, nearly four hours ; in the meantime,
all its annexing vessels had been severed—its associated organs removed,
without destroying its pulsatory action, which, in four hours, declined
from 36 to 16 per minute. It was roughly handled; its blood emptied
out; it underwent pressure and considerable desiccation, but was still
active when the observations ended. On other occasions, I have ob-
served the continuous action of this organ, for seven hours, proving that
the favorite assumption of physiologists concerning the blood, as being
the necessary stimulus to the heart’s motion, is an error. There is
a simpler explanation, namely, the inherent force of that hollow muscle
itself.
“June 5th, 1818.—Dr. Young, Mr. Barbot, and myself, performed the
following experiments on an alligator three feet and seven inches in
length, occupying a period of seven hours, during the greater portion
of which, these gentlemen were constantly present. The animal was
not very vigorous. It had a congenital mal formation or deficiency,—
or, what is more probable, it had been early in life mutilated, by which
the entire tongue, and the whole flooring of the under jaw, were re-
moved. The skeleton of the lower jaw was covered with a thin, white,
dense membrane, all the soft parts having been removed. The animal
was emaciated, and highly anemic ; its blood was thin and pale, owing,
doubtlessly, to the difficulty of catching and swallowing food, in the
absence of the tongue, and the flooring to the under jaw. The animal
was decapitated, and the great artery of the neck was ligated. On
touching the lid, the eyes closed. It bit when A stick touched its teeth.
On passing a wire into the foramem magnum, and breaking up the
brain, these actions ceased. The sensational, intelligential, motory
and volitional phenomena of the trunk, were the same as in the cases
already described. About one hour after decapitation, a wire was
passed down the spinal canal beyond the hind legs. By repeated ma-
nipulations, the texture of the cord was completely disorganized. The
vigor and promptness of its intelligential motions were greatly im-
paired, but not wholly lost. During an hour after this destruction of
the cord, punctures, or fire, caused slight motions of a definite charac-
ter, like those before decapitation, but not constantly. The contrac-
tions of the heart were 48 per minute. The intestines, seven hours
after decapitation, and five after removal from the body, presented, as
usual, contractile phenomena, of a peculiar character.
“August 20th, 1849.—Experiments on two alligators; each about three
feet long. [Circumstances, not necessary to mention, prevented me
from taking full notes at the time of these vivisections. Drs. Cartwright,
Smith, Nutt, Powell, Hire, and Mr. Barbot, were present, together
with several gentlemen not of the profession, among whom was Professor
Forshey.] The alligator, No. 1., was tied on its back. The trachea
was ligated in the middle of the reck. No blood was lost. The inci-
sion was closed with stitches, and strips of adhesive plaster. The
animal was returned to its den, where it was found, apparently dead,
about half an hour after. I proceeded to dissect the viscera for a few
minutes, when at the request of Mr. Forshey, (a learned and able cul-
tivator of science,) the ligature was removed from the windpipe. The
latter was opened. A tube was introduced into the opening. The
lungs were repeatedly inflated by Mr. Forshey. The animal was,
thereby, soon restored to life. I proceeded to demonstrate the viscera,
and to remove the organs. After this was done, (which occupied
about two hours,) the animal ceased to show any signs of sensation, or
voluntary motion. It lived, after the ligation of the trachea, a much
shorter time than decapitated alligators. The heart, both before and
after its removal from the body, maintained its contractile motions, as
long as observed, that is, for three hours. The apparent death from the
tying of the trachea, in so short a time, was a result that I did not ex-
pect, because, I had often taken what I supposed to be effectual means
to ascertain whether these animals breathed, when left undisturbed, but
I never could detect them in the act of breathing, though, when alarmed
or angry, they hiss and blow almost constantly. Baron Humboldt
says, from personal observation, that they live two or three days with-
out respiration at all—sans respirer de tout.
“ In this experiment, the animal did not appear to suffer but little,
immediately, from the ligation of the trachea. Before the removal of
the ligature, and the inflation of the lungs, life seemed quite extinct
—the limbs relaxed—the body supple and motionless. If my recollec-
tion be accurate, the incipient dissection, (that is, before pulmonary in-
flation,) did not elicit any sensational, or volitional phenomena.—
If this be so, (and it is worthy of being tested by experiment,) it would
seem that this form of death is more complete, than that by decapitation.
After the latter operation, however, the removal of the lungs does not
interfere with the phenomena, as already narrated.
“ Experiments on the alligator, No. 2 : (The same gentlemen as be-
fore mentioned, were present:) The decollation was not followed by a
projecting stream of blood, as is usual; no ligature was applied to the
great artery of the neck. The dull hatchet used in severing the spine
of the neck, had probably bruised the artery as in torsion and gun-shot
wounds. Hence the haemorrhage was not great, though considerable.
“ I carried the handle of the knife towards the eye, to ascertain
whether it would wink, whereupon the ferocious, separated head,
sprang up from the table with great force, at me, passing very near
my breast, which received several drops of blood ; it alighted upon the
floor, from six to eight feet distant from its original position It missed
me, because I was standing at the side, and not in front of the head.
Although, I have examined carefully, all the muscles of the head, I
cannot find one that accounts for this feat of combative muscular
motion. The angles of the mouth recede so much in this animal, that
after decollation, including the medulla oblongata, the head seems almost
like two separate pieces,—the superior and the inferior maxillary bones,
being joined chiefly by the great masseter muscles, for only a short
distance. These great muscles, (the masseters), which are curved
having their concavity anteriorly, are adapted only to vertical action,
as in biting—the great muscles of the tongue act backward and upward
against the palatine region :—whence then this quick, violent, forward
motion, or rather, as in this case, diagonal leap of six or eight feet—for
the head deviated to the left, where I was standing, evidently with the
intention of biting me ? The trunk, in this, as in all cases, possessed
no power of forward motion. This curious fact with respect to decap-
itated animals, noticed by M. Magendie, and other vivisectors has been
attributed to the loss of the cerebellum ; but whether this loss of forward
motion in the alligator, be owing to a division of the spine, and great
muscles, or to the separation of the larger or smaller brain, or both, is
not very evident, yet the fact which I have noticed respecting the for-
wardmotion of the separated head, is, perhaps, a circumstance favora-
ble to this view. That a voluntary, spontaneous and powerful motion,
—in fact a diagonal leap, should be performed by the separated head,
must therefore appear astonishing to one acquainted with the muscular
organization. It is difficult to understand, how the cerebellum could
thus act alone.
“ For about two hours, the headless trunk of the last mentioned alli-
gator, exhibited such phenomena as are usually attributed to the brain,
namely, sensation, volition, and intelligential motion, as tested by the
application of bits of ignited paper, wounds and the like, whereupon,
the usual indicants of pain were elicited with great promptness and
precision: it trembled, receded, rolled over, curved, placed its.limbs
accurately to the exact spot, and removed the offending cause. In
certain places this was exceedingly difficult, as on the spine between
or near the shoulders, or hips. It always used the limbs the best adap-
ted for the purpose. If the fire was too remote, as when applied to
the tail, the whole body was thrown into the most favorable position,
for the purpose of reaching, and removing the same. If the fire was
placed on the table, in a position to annoy, yet without touching, the
animal, as if'endowed with sight, reached, and always accurately, to
the exact spot, and either extinguished the fire, or removed it. As
upon former occasions, if the animal found that the fire was continued
at the same spot, and that it could not remove it, which was sometimes
the case, owing to continuous, or repeated applications, and carefully
manoeuvring, it curved the body—scratched violently, manoeuvred skill-
fully, and then as a last resort, rolled quite over, laterally, always
from, never towards the fire and operator.
“ After these experiments had progressed for some time, Dr. Cart-
wright desired me to cut off the neck close to the shoulders. This was
done, but the intelligential, sensational, and volitional motions con-
tinued as before—p. 20.