August 20, 1885 | 
NATURE 379 
muscles have special areas for their movement, ranged along the 
margin of the hemisphere, and dipping over into the longitudinal 
fissure. Thus all the muscles of the body are now accounted 
for, and I will first draw special attention to the fact that they 
are arranged in the order, from below upwards, of face, arm, 
leg, and trunk. 
The consideration of this very definite arrangement led Dr. 
Lauder Brunton to make the ingenious suggestion that it followed 
as a necessary result of the progressive evolution of our faculties. 
For premising, in the first place, from well-ascertained broad 
generalisations that the highest centre, physically speaking, is 
also the highest functionally and most recent in acquirement, we 
find that the lowest is the face, and then we remember that the 
lowest animals simply grasp their food with their mouth. I 
imagine it is scarcely necessary for me to repeat the notorious 
confession that our faculties are arranged for the purpose of 
obtaining food as the primary object of what is called bare 
existence. 
Proceeding upwards in the scale of evolution we next find 
animals which can grasp their prey and convey it to the mouth, 
and so we find next to the face area evolved that for the arm. 
And so on, the next step would be the development of the 
legs to run after the prey, and here is the leg centre; while, 
finally, the trunk muscles are dragged in to help the limbs more 
effectually. 
To my mind this idea receives overwhelming support from the 
consideration of the fact that, the higher our centres are the 
more they require education ; the infant, for instance, in a few 
days shapes its face quite correctly to produce the food-inspiring 
yell, yet takes mnths or years to educate its upper limbs to aid 
it in the same laudable enterprise. Finally, what terrible pro- 
bation some people pass through at the hands of dancing- 
masters before their trunk muscles jwill bend into the bow of 
politeness. 
Now to return to the lower end of the fissure of Rolando, to 
the areas for movements of the face ; it was lonz ago pointed out 
by the two Dax’s and Prof. Broca that when this portion of the 
brain immediately in front of the face area was destroyed, that 
the person lost the power of articulate speech, or was only 
capable of uttering interjections and customary ‘‘strange oaths.” 
In fact this small portion of the left side of our brains (about 
¥% square inches) is the only apparatus for expressing our 
thoughts by articulating sounds, and note particularly that it is 
on the left side. The corresponding piece on the right side 
cannot talk asit were. This remarkable state of things is re- 
versed in left-handed people. In these the right hemisphere 
predominates ; and so we find that when this portion was 
diseased, there followed aphasia, as it is called. While, how- 
ever, the right side customarily says nothing, it can be taught to 
do so in young people, though not in the aged. 
Before leaving these motor areas, let me repeat, by way of 
recapitulation, that the only truly bilaterally acting areas are 
those for the lower facial and throat muscles. This is a most 
important fact, for the idea has recently been propounded that 
both sides of the body are represented in each motor region of 
each hemisphere. That is to say, each motor area has to do 
with the movements of both upper limbs, for example. In 
support of my contention that this is not in accordance with 
clinical facts, let me here show you photographs of the brain of 
aman who was unfortunate enough to suffer destruction of the 
fibres leading from one motor area. Here you see a puncture in 
the brain which has caused hemorrhage beneath the fissure of 
Rolando and the motor conyolutions in front and behind it. 
In this transverse section of the same spot you see that the 
hemorrhage has ploughed up the interior of the brain. Here is 
the cortical grey matter, but its fibres leading down to the 
muscles are all destroyed. 
Now in examining this patient I asked him to move his left 
arm or leg ; he was perfectly conscious, and, understanding the 
question, made the effort as we say, but no movement occurred. 
Now if both sides of the body are represented in each hemi- 
sphere, it seenis to me that such a case would be impossible, or 
at least that a little practice would enable the other hemisphere 
to do the work ; but all clinical facts say that, once destroyed, 
the loss is never recovered. 
If we examine this motor region of the cortex with the micro- 
scope we of course find these large corpuscles, which we have 
learnt are those which alone give energy to the muscles. 
But you must not imagine that the motor region consists solely 
of these corpuscles. On the contrary, as youscee in this diagram, 
we have several layers of corpuscles. I shall return to this 
arrangement of the corpuscles directly. 
Looking back at the surface of the brain you notice that I 
have only accounted for but a small portion of the cortex. 
Dr. Ferrier was the fist to show that the portion of cortex 
which perceived (and I use the word in its strictest sense) the 
sensation of light was this part, and it is therefore called the 
“visual centre or area.” From recent researches it would appear 
that we must give it the limits drawn on this diagram. Below 
it we find the centre for hearing. 
Thus we know where two sense perceptive centres are 
situated. 
Microscopical investigation shows that this sensorial portion 
of the cortex is very deficient in large corpuscles, and is cor- 
respondingly rich in small cells. Here in this diagram you see 
these two kinds of structure in the cortex cerebri. Note the 
greater number and complication of the small corpuscles in the 
sensory part of the cortex, and the comparatively fewer though 
much larger corpuscles in the motor region. 
It seems to me that several beliefs are justified by these facts. 
In the first place the movements produced by the action of 
these motor centres are always the same for the same centre 5 
consequently it has only one thing to do, one idea as it were. 
Thus, for instance, bending of the arm: this action can only 
vary in degree, for the elbow will not permit of other move- 
ments. Hence we may look uponitas one idea. Now observe 
that where one idea is involved, we have but few corpuscles. 
Next consider the multitude of ideas that crowd into our mind 
when we receive a sensation. One idea then rapidly calls up 
another, and so we find anatomically that there are a correspond- 
ing much greater number and complication of nerve-corpuscles. 
To sum up, I believe we are justified in asserting that where 
in the nervous system a considerable intensity of nerve-energy is 
required—(e.g., for the contraction of muscles)—you find a few 
large corpuscles and fibres provided, and that where numerous 
ideas have to be functionalised there numerous small corpuscles 
are arranged for the purpose. 
But now the special interest attaching to the sensory per- 
ceptive areas is that they, unlike the motor areas, tend to be 
related to both sides of the body. With our habit of constantly 
focussing the two eyes on one object, it will strike you at once 
that habitually we can only be attentively conscious of one 
object at a time, since both eyes are engaged in looking at it, 
and, as you know, we cannot as a matter of fact look at two 
things at once. 
Hence I take it, both sensory perceptive centres are always 
fully occupied with the same object at the same moment, and 
that therefore we have complete bilateral representation of both 
sides of the body ineach hemisphere. Asa further consequence, 
each sensory perceptive area will register the idea that engaged 
it; in other words, both centres will remember the same thing. 
Thus it happens that each sensory area can perform the duty of 
the other, and therefore it is a matter of comparative indiffer- 
ence whether one is destroyed or not, and as a matter of fact 
when this happens we find that the person or animal recognises 
objects as they actually are, and in fact has no doubt as to their 
nature. Here you see anatomically the reason of this peculiarity 
is found to be that the optic or seeing nerves cross one another 
incompletely in going to each hemisphere, and thus each sensory 
centre represents half of each eyeball. 
I must pass rapidly to the description of the rest of the surface 
of the brain—the hinder and front ends. At the outset I must 
admit that all our knowledge concerning them is very hypo- 
thetical in the absence of positive experimental results. 
This much we can say, that they are probably the seats of in- 
tellectual thought, for many reasons which I have not time to 
detail. Further, we know that these intellectual areas are 
dependent for their activity entirely on the sensory perceptive 
centres, for the dictum that there is no consciousness in the 
absence of sensory stimulation is very well established, as I shall 
now show you, however astounding it may appear. In the first 
place, you will remember that when we wish to encourage that 
natural loss of consciousness which we call sleep, we do all we 
can to deprive our sense-organs and areas of stimulation; thus 
we keep ourselves at a constant temperature, we shut off the 
light, and abolish all noises if we can. But a most valuable 
observation was made a few years ago by Dr. Striimpell, of 
Leipzig, who had under his care a youth, the subject ofa disease 
of the brain, &c., which, while destroying the function of one 
eye and ear, besides the sensibility to touch over the whole body, 
r 
