cextatr, bit many considerations*lead to the inference that/it may 
not be later than the latter part of the carboniferous period. 
rae "SECTION D.—Brotocy. 
De: ; DEPARTMENT OF ANATOMY AND PHYSIOLOGY. 
_ The Localisation of the Functions in the Brain, by Professor 
‘Ferrier. 
All are agreed that it is with the brain that we feel, and think 
and will, but whether there are certain parts of the brain devoted 
‘to particular manifestations is a subject on which we have only 
imperfect speculations or data_too insufficient for the form- 
ation of a scientific opinion. The general view is that the brain 
as a whole subserves mental operations, and that there are no 
eh specially devoted to any particular functions. This has 
n recently expressed by so high an authority as Professor 
Séquard. The idea rests chiefly on the numerous facts of dis- 
ease with which we are acquainted. There are cases where 
extensive tracts of brain are destroyed by disease, or removed 
after a fracture, apparently with no result as regards the mind of 
the individual. Along with these facts we have others which 
are yery curious, and which hardly seem to agree with this doc- 
trine. One of these is that when a certain part of the brain is 
diseased, in Aphasia, the individual is unable to express himself 
jn words. Other curious phenomena have been well described 
by Dr. Hughlings Jackson, viz., that certain tumours or patho- 
logical lesions in particular parts of the brain give rise, by the 
ifritation which they keep up, to epileptiform convulsions of the 
whole of one side, or of the arm or leg or the muscles of the 
face; and from studying the way in which these convulsions 
show themselves he was able to localise very accurately the seat 
of the lesion. ~ ~ 
_ The great difficulty in the study of the function of the brain 
has been in the want of a proper method. When we study the 
function of a nerve, we make our experiments in two ways. In 
the first place, we irritate the nerve by scratching or by elec- 
tricity, or by chemical action, and observe the effect ; and in the 
second place; we cut the nerve, and observe what is lost. In 
regard to the brain and nervous system, the method has been 
almost entirely, until recently, the method of section. It has 
been stated by physiologists that it is impossible to excite the 
brain into action by any stimulus that may be applied to it, even 
that of an electric current ; they have, therefore, adopted the 
‘method of destroying parts of the brain. This method is liable 
to many fallacies. The brain is such a complex organ that to 
destroy one part is necessarily to destroy many other parts, and 
the phenomena are so complex that one cannot attribute their 
loss to the failure only of the parts which the physiologists have 
attempted to destroy. 
About three years ago, two German physiologists, Fritsch and 
Hitzig, by passing galvanic currents through parts of the brains 
of dogs, obtained various movements of the limbs, such as ad- 
duction, flexion, and extension. They thus discovered an impor- 
tant method of research, but they did not pursue their experi- 
ments to the extent that they might have done, and perhaps did 
not exactly appreciate the significance of the facts at which they 
had arrived. 
I was led to the experiments which I shall have to explain by 
the effects of epilepsy and of chorea, which have been explained 
to depend upon irritation of parts of the brain. I endeavoured 
to imitate the effects of disease on the lower animals, and deter- 
mined to adopt the plan of stimulating the parts of the brain by 
electricity, after the manner described by Fritsch and Hitzig. 
I operated on nearly a hundred animals of all classes—fish, 
frogs, fowls, pigeons, rats, guinea pigs, rabbits, cats, dogs, 
jackalls, and monkeys. The plan was to remove the skull, and 
sa the animal in a state of comparative insensibility by chloro- 
form, So little was the operation felt that I have known a 
monkey, with one side of the skull removed, awake out of the 
state induced by the chloroform, and proceed to catch fleas or 
eat bread and butter, When the animal was exhausted I some- 
times gave it a little refreshment, which it took in the midst of 
the experiments. 
First, as to the experiments on cats, I found that on applying 
the electrode to a portion of the superior external convolution 
the animal lifted its shoulder and paw (on the opposite side to 
that stimulated) as if about to walk forward ; stimulating other 
parts of the same convolution, it brought the paw suddenly back, 
or os out its foot as if to grasp something, or brought forward 
its 
ind leg as if about to walk, or held back its head as if 
NATURE 
ayy 
astonished, or turned it on oné side as if looking at something, 
according to the particular part stimulated. The actions pro- 
duced by stimulating the various parts of the middle external 
convoltition were a drawing up of the side of the face, a back- 
ward movement of the whiskers, a turning of the head, and a 
contraction of the pupil respectively. A similar treatment of 
the lower external convolution produced certain movements of 
the angles of the mouth ; the animal opened the mouth widely, 
moved its tongue, and uttered loud cries, or mewed in a lively 
way, sometimes starting up and lashing its tail as if in a furious 
rage. The stimulation of one part of this convolution caused 
the animal to screw up its nostrils on the same side ; and, curi- 
ously enough, it is that part which gives off a nerve te the nostril 
of the same side. 
Results much of the same {character were produced by the 
stimulation of the corresponding or homologous parts of the 
rat, the rabbit, and the monkey. Acting upon the anterior 
part of the ascending frontal convolution the monkey was 
made to put forward its hand as if about to grasp. 
Stimulation of other portions acted upon the biceps, and 
produced a flexing of the forearm, or upon the zygomatic 
muscles. The part that appeared to be connected with the 
opening fof the mouth and the moyement of the tongue was 
homologous with the part affected in man in cases of aphasia. 
Stimulation of the middle temporo-sphenoidal convolution pro- 
duced no results ; but the lower temporo-sphenoidal, when acted 
upon, caused the monkey to shut its nostrils. No result was 
obtained in connection with the occipital lobes. 
These experiments have an important bearing upon the diag- 
nosis in certain kinds of cerebral disease, and the exact localisa- 
tion of the parts affected. I was able to produce epileptic 
convulsions of all kinds in the animals experimented upon, as 
well as phenomena resembling those of chorea or St. Vitus’s 
dance. The experiments are also important anatomically, as in- 
dicating points of great significance in reference to the homology 
of the brain in lower animals and in man, and likewise served to 
explain some curious forms of expression common to man and 
the lower animals, The common tendency, when any strong 
exertion is made with the right hand, to retract the angle of the 
mouth and open the mouth on the same side, had been stated by 
Oken, in his Matur-geschichte, to be due to the homology be- 
tween the upper limbs and the upper jaw ; the true explanation 
being that the moyements of the fist and of the mouth are in 
such close relation to each other that when one is made to act 
powerfully the impression diffuses itself to the neighbouring part 
of the brain and the two act together. 
The experiments have likewise a physiological significance, 
There is reason to believe that when the different parts of the 
brain are stimulated, ideas are excited in the animals experi- 
mented upon, but it is difficult to say what theideasare. There 
is, no doubt, 2 close relation between certain muscular move- 
ments and certain ideas which may prove capable of explanation. 
This is supported by the phenomena of epileptic insanity. The 
most important guide on the psychological aspect of the question 
is the disease known as Aphasia, The part of the brain which 
is the seat ot the memory of words is that which governs the 
movements of the mouth and the tongue. In Aphasia the 
disease is generally on the left side of the brain, in the posterior 
part of the inferior frontal convolution, and it is generally 
associated with paralysis of the right hand, and the reason might 
be supposed to be that the part of the brain affected is nearly 
related to the part governing the movements of the right hand, 
It is essential to remember that the movements of the mouth 
are governed bi-laterally from each hemisphere. The brain is 
symmetrical, and I hold it to bea mistake to suppose that the 
faculty of speech is localised on the left side of the brain. The 
reason why an individual loses his speech when the left side of * 
the brain is diseased is simply this. Most persons are right- 
handed, and therefore left-brained, the left side of the brain 
governing the right side of the body, Men naturally seize a 
thing with the right hand, they naturally therefore use rather the 
left side of the brain than the right, and when there is disease, 
there the individual feels like one who has suddenly lost the use 
of his right arm. 
I may, finally, briefly allude to the results of stimulating the 
different'ganglia. Stimulation of the corpora striata causes. the 
limbs to be flexed ; the optic thalami produces no result: the 
corpora quadrigemina produce, when the anterior tubercles are 
acted upon, an intense dilatation of the pupil, and a tendency to 
draw back the head and extend the limbs as in opisthotonos ; 
