THE
MEDICAL EXAMINER,
AND
RECORD OF MEDICAL SCIENCE.
NEW SERIES.— NO. XCIX.—MARCH, 1 8 53.
ORIGINAL COMMUNICATIONS.
Experimental Researches applied to Physiology and Pathology.
By E. Brown-SeQUARD, M. D., of Paris.
(Continued.)
XXII.—ON THE INCREASE OF ANIMAL HEAT AFTER INJURIES
OF THE NERVOUS SYSTEM.
In another part of this series* I have endeavored to prove
that the local increase of temperature following the section of
the sympathetic nerve, is the result of paralysis of the blood-
vessels. I will now relate some other cases in which a local
increase of temperature takes place after various other inju-
ries of the nervous system, and apparently in consequence of
the same cause.
* Medical Examiner, Auaust 1853, b. -489.
It was known, long ago, that an injury to the nervous system
might be followed by a partial or even a general elevation of
animal heat. Sir B. Brodie says,f Mr. Chossat has published an
account of some experiments on. animals, in which he found
+ Medico-Chirurg, Transactions, 1837. Vol. xx., p. 132.
that the division of the superior portion of the spinal cord
produced a remarkable evolution of animal heat, so that it was
raised much above the natural standard. I have made experi-
ments similar to those of Mr. Chossat, and have met with similar
results. I have also seen several cases in which an accidental
injury of the spinal cord has produced the same effect. The
most remarkable of them was that of a man who was admitted
into St. George’s Hospital, in whom there was a forcible separa-
tion of the fifth and sixth cervical vertebrae, attended with an
effusion of blood within the theca vertebralis, and laceration of
the lower part of the cervical portion of the spinal cord. Res-
piration was performed by the diaphragm only, and, of course,
in a very imperfect manner. The patient died at the end of
twenty-two hours ; and, for some time previous to his death,
he breathed at very long intervals, the pulse being weak and
the countenance livid. At last there were not more than five
or six inspirations in a minute. Nevertheless, when the ball
of a thermometer was placed between the scrotum and the
thigh, the mercury rose to 111° of Fahrenheit’s scale.
•Immediately after death, the temperature was examined in the
same manner, and found to be still the same.
Brodie was mistaken as regards the experiments of Chossat.
Instead of finding an increase in the animal heat after the sec-
tion of the inferior portion of the spinal cord, Chossat found
a considerable diminution in the temperature of dogs. But in
two 'cases, where the spinal cord was divided at about the
level of the last dorsal vertebra, in dogs, Chossat* found an
increase in the animal heat. In one of these experiments, the
increase was from 41°.1 to 41°.5 Cents., (105°.98 to 106°,7
Fahr.) In the other, the increase was from 41°.l to 42°.9
Cs., (105°.98 to 109°.6.)
Dr. Macartney! found an increase in the temperature of
parts paralyzed in consequence of the division of their nerve.
II. Nasse,J who made many experiments on this subject, some-
j- Treatise on Inflammation, 1838, p. 13.
t Vutersurchunger zur Physiol, und Pathol., 1839, v.i-i., p. 190.
Mem. sur 1’ influence du syst. nerv. sur la chai. anim. These de Paris.
No. 126.—1820, p. 35. Exps. xxiii and xxiv.
times observed an elevation in the temperature of the pa-
ralyzed parts after the division of the sciatic nerve, or after
the partial destruction of the spinal cord.
In more than twenty experiments, I only once found an
increase in the temperature of the leg of a guinea-pig, after the
section of the sciatic nerve. This increase lasted about two
or three days after the operation, and it was of two degrees Fahr.
After a complete transversal section of the spinal cord in the
lumbai' region, in birds and mammals, I found, repeatedly,
an increase of one, two or three degrees Fahr, in the temperature
of the paralyzed parts. I ascertained that it is not in conse-
quence of an increase of the general temperature of the animal
that such an increase exists. It is to be found only in the
paralyzed parts.
I never found any increase of temperature after a complete
transversal section of the spinal cord, either in the cervical or in
the dorsal region.
After a section of a lateral half of the spinal cord, at the
level of one of the three or four last dorsal vertebrae, I have
almost constantly found an increase in the temperature of
the posterior limb on the side of the section. The elevation
varied from one to four degrees Fahr. On the contrary, there
was a diminution of from one to five degrees Fahr, in the
temperature of the other leg. In some cases, in consequence of
the increase of temperature on one side and its diminution on
the other side, I found a difference of six or seven degrees
Fahr, in the temperature of the two limbs. It is very remark-
able that, together with the increase of temperature in one
limb, there is an augmentation of sensibility, and with the di-
minution of temperature in the other limb, there is also a dimi-
nution of sensibility.
Since the publication of the results of my experiments on the
sympathetic nerve, I have performed them many other times,
and I have found that the result is not so constant as Dr. A.
Barnard and myself had admitted. In some rabbits there was
no decided increase in the vascularization and in the tempe-
rature of the face. I ought to say that, in these cases, the two
ears were already warm, and very vascular before the operation.
I have found, also, that generally in very cold weather the ex-
tremity of the ear of rabbits, on the side of the section of the
sympathetic nerye, remains cold.
From my experiments and from the observations and experi-
ments of Brodie, Chossat, II. Nasse and Macartney, it results
that the following opinion of Dr. Cl. Bernard is incorrect. lie
says :	“ It is known that injuries of the cerebro-spinal ner-
vous system constantly produce a total or a partial diminu-
tion in the temperature of animals, either when a nerve has been
divided or when the injury is made on the nervous centres.”*
lie says also that an injury of the sympathetic nerve produces
a very rapid increase of temperature; so that the sympathetic
nerve and the cerebro-spinal nervous system are considered by
Dr. Bernard as completely different, one from the other, as to
the influence on animal heat when they are injured. The one
should increase and the other diminish animal heat.
*Gaz. Medic, de Paris, Vol. 7, No. 14, p. 227.
The truth is that these two effects—increase and diminution—
may exist after an injury of either the sympathetic or the cere-
bro-spinal nervous system and, in both cases, the increase may
exist, at first, and be followed by a diminution.
t Vide : Chossat, loco cit., pp. 41-46.
Before pointing out the co-existence of certain facts with the
increase or diminution of animal heat, I think it necessary to es-
tablish a distinction between the cases of increase of animal heat
after injuries of the nervous system.
In some cases (as those related by Brodie) there has been an
increase of temperature above the natural standard of animal
heat. These are very extraordinary and very rare cases, and
it is not my intention to attempt to explain them here. In the
cases, the degree of temperature, although increased in some other
paralyzed parts, has not been above the normal degree of blood
heat. This is the only kind of increase of animal heat that I
have observed, and this I will attempt to explain.
I have found that,—ceteris paribus,—the more the arteries
and capillaries are dilated, the higher is the degree of tempera-
ture. This law is proved by the following facts:
1st. In all the cases of paralysis (from whatever cause)
where I have found a diminution in the degree of temperature
of a paralyzed part, the arteries and capillaries were evidently
much contracted.
2d. In the cases where the temperature was normal, the blood-
vessels were of their natural size.
3d. In the cases where the temperature was increased, I have
constantly found the arteries and capillaries enlarged.
4th. In some cases, I have found the same changes occurring
in the temperature and in the blood-vessels. The temperature
at first was greater than usual and the blood-vessels dilated ;
afterwards both the temperature and blood-vessels became natu-
ral; and, at last, the temperature becoming lowrer than usual,
the size of the blood-vessels became smaller.
I need not say that the changes occurring in paralyzed
parts in accordance with the size of the blood-vessels were the
results of the differences in the amount of blood passing in these
parts.
Now, it will be asked how, in certain cases of palsy, the size
of the blood-vessels is larger than usual, and smaller in other
cases. I cannot explain how it is so, but I can assert that it is
a fact.
From the facts and reasonings related in this article, I draw
the following conclusions :
1st. An injury of the nervous system may produce in the
parts, which then become paralyzed, either an increase or dimi-
nution of temperature.
2d. The sympathetic nerve and the cerebro-spinal nervous
system appear not to be different one from the other, in this
respect.
3d. The degree of temperature of paralyzed parts depends on
the quantity of blood they receive ; and this quantity varies ac-
cording to the size of the arteries and capillaries of these parts.
4th. It is a fact, hitherto unexplained, that the arteries and
capillaries may be either dilated, normal, or contracted in para-
lyzed parts.
XXIII---CAUSE OF THE STOPPING OF THE HEART’S MOVEMENTS,
PRODUCED BY AN EXCITATION OF THE MEDULLA OBLONGATA OR
THE PAR VAGUM.
E. H. and E. Weber have discovered a singular fact, hitherto
unexplained. When the par vagum or the medulla oblongata is
excited by a po.werful electro-magnetic current, in a living
animal, the movements of the heart are suddenly stopped. This
should be what is known for all motor nerves and muscles, if the
cessation of the movements of the heart was the result of a per-
manent contraction. But the heart is not at all contracted, and,
on the contrary, it remains perfectly placid.
This is entirely different from what we know to be the case
for other muscles.
I have found that a violent mechanical excitation of the me-
dulla oblongata produces also the same stopping of the heart’s
action.
Is the heart in a state of rest in consequence of a loss of its
irritability or of an interruption of the excitation necessary to
its action ? The following fact proves that this second opinion
is the right one. When the heart is stopped, every direct exci-
tation upon it produces some beatings, and then, its irritability
appears to be entire. The stopping, consequently, depends on
the absence of excitation.
The cause exciting the heart to beat is in the blood contained
in the capillaries of this organ, as I will try to prove in another
article. Now, if we suppose that the galvanization of the par
vagum produces a complete constriction of the capillaries of the
heart, it is easy to understand why the heart is stopped : it is
because the excitation cannot take place on account of the ex-
pulsion of the blood from the capillaries.
It will be asked on what ground we base the supposition that
the capillaries are so contracted that they prevent entirely, or
nearly so, the passage of the blood. I will answer :
1st. That it is known that a galvanization of certain nerves
(and I have discovered that it is so with the capillaries of the face
and ear when the sympathetic nerve is galvanized) may pro-
duce a considerable constriction of capillaries.
2d. That it is known that the nerves of the heart are distri-
buted much more to its blood-vessels than to its muscular tissue.
3d. That, by our supposition, -we place the fact of the stopping of
the heart’s movements among the "well known facts, that an excita-
tion of a molar nerve produces a contraction of the muscles to
which it is distributed ; and, therefore, we are not obliged to admit
that an excitation of a nerve is able to produce directly either a
contraction of or the cessation of existing contractions.
There is a practical consequence to be drawn from the fact that
in the case of an excitation of the medulla oblongata, the stopping
of the heart is not produced by a loss of irritability of this organ.
Many cases of syncope are produced by a stopping of the
heart’s movements in consequence of the influence of an emotion
on the medulla oblongata. In these cases it would be of
very great importance to excite directly the beatings of the heart,
either by compression of the chest or by an application of gal-
vanism.
We ought to say that galvanism applied directly to the heart
increases its beatings instead of diminishing them.
XXIV.—ON A SINGULAR DISTURBANCE IN THE VOLUNTARY MOVE-
MENTS, APPARENTLY PRODUCED BY AN ACTION OF ATMOSPHERIC
AIR ON THE GRAY MATTER OF THE SPINAL CORD, IN BIRDS.
Some years ago I discovered that after the removal of a large
quantity of the gray matter that exists in bird's, on the posterior
surface of the spinal cord, in the lumbar region, a great disturb-
ance took place in the voluntary movements. I attributed this
disturbance to the loss of gray matter. I have found, three
or four months since, that the same disturbance existed in the
voluntary movements after I had merely laid bare the gray
matter, and immediately after it had been exposed to the action
of air.
I am perfectly satisfied that it is not in consequence of a
mechanical excitation of the spinal cord, accidentally produced
during the operation of the removal of the bones and membranes,
that this disorder takes place.
When the spinal cord is laid bare elsewhere than in the region
of the lumbar enlargement—that is, in any place where the white
substance covers completely the gray matter—there is no disturb-
ance produced in the voluntary movements.
That disturbance very much resembles the so-called tituba-
tion which exists after either the removal of the cerebellum or
the section of muscles of the posterior part of the neck. At
each movement of progression, the animal tends to fall either
forwards, backwards, or laterally. It does not fall completely,
but is obliged, in order to avoid falling, to make use of its wings,
its tail and its beak.
(To be continued.)