18 
NATURAL HISTORY. 
brow and those of the cheeks, so large and important, are distinctive of the adult male animal, and a 
skull possessing them belongs to the Gorilla and to no other animal. 
The females and the young of both sexes have not the top ridges, and the others are small in 
comparison with those of the male adults. 
Clearly the ridges give strength to the head, muscular power to the jaws, and what is of great 
importance to a large active animal, do not interfere with the lightness of the strong skull. 
The skull is hollow beneath the top and back ridges, and this space is occupied by the brain and 
its investing membranes, and the nerves coming from it, to supply the muscles of the face and head, 
the skin over them, and the organs of special sense, such as the eye, the ear, and the nose. The space 
is considerable, and for an Ape the Gorilla has a large brain. He has a large body, very many muscles 
capable of complicated movement, and he can see, hear, and smell admirably ; and as the nerves which 
supply the necessary energy for all this come from the great nervous centre, as the brain is called, it 
must be of considerable size and complexity. Moreover, as many of the motions and sensations of 
the Ape resemble those of man, the brains of both will resemble each other to a certain extent. But 
all that part of the brain which serves in a manner, as yet past our comprehension, to assist the pro- 
duction of the high intelligence and moral powers of man, we should expect not to find in the purely 
sensual animal, and the expectation is realised. Again, although bone for bone, muscle for muscle, 
and blood-vessel for blood-vessel, those of the great Ape and man may bo compared with wonderful 
exactitude ; still man in relation to the Gorilla has a greater power of elegance of movement, and 
of producing complicated muscular efforts, and of employing many different muscles to produce a 
common end, and therefore his nervous system must be all the more perfect. Thus, the Ape cannot 
imitate the graceful actions which sway tlie body as when a well-made man walks leisurely, and it 
cannot get all the muscles of the mouth, tongue, and larynx (or organ of voice) to act simultaneously 
and orderly, so as to produce the sound of articulate voice. Yet these actions are performed by man 
without any special effort ; they may be done without thinking, and are mechanical, as it were, or 
more properly, “automatic,” done as if by a machine; they require a very perfect arrangement of 
the nervous system, and an unusual amount of nervous matter. 
No amount of schooling, could it be given, would ever make a Gorilla entertain the notion of 
insuring its life ; arithmetic is impossible ; the fine arts and poetry are unattainable, and therefore by 
so much is its brain the smaller and simpler. 
The brain case, or the space enclosed by the crested skull bones, is compactly filled with the 
nervous material in all animals, so it is only necessary to ascertain the relative dimensions of the 
spaces in different animals to get a notion of the difference in the sizes of their brains. The space 
can be measured by filling it with sand, and then measuring its bulk in a proper measure. 
Some Gorillas have larger spaces for the brain than others, and in this they resemble man, 
for there is a considerable difference between the capacity or the size of the space in a well-educated 
European and a savage Australian. And, doubtless, some Gorillas are cleverer than others, or are 
more active, generally speaking, so have larger brains ; but an average may be taken of the different 
sizes in them as in man, and the results come out as follows : — 
The average or mean size or capacity of the brain case in the Gorilla is about 31 cubic inches, a 
cubic inch being a six-sided space of one inch long, broad, and high. In man, the European may have 
a brain case holding 114 cubic inches, and the Australian only 63 cubic inches; the mean of the 
European size is 93 cubic inches, that of the Australian being 75 . Hence the brain case, and there- 
fore the mass of the substance of the brain of the Gorilla, is not one-lialf that of the lowest race of man. 
Only the brains of young Gorillas have been examined, and these have not been in a very satis- 
factory state ; but enough has been gleaned from their study to determine that they are not so high, 
wide, or long, relatively, as those of mankind. The brain of man is a wonderfully complex structure, 
and the nervous matter is folded and packed in many ways or “ convolutions,” and the nerves arise 
from special parts which are connected by cross and long fibres or “ commissures.” All these structures 
exist, but not in perfection, in the Gorilla’s brain ; and although the nerves are large, that portion 
of the brain which originates their energy and action is much smaller than in man. 
Apparently the brain grows to a certain age in the Gorilla, and then the skull increases in out- 
ward size, and the creature has a huge body, with mental capacities far below those of a child or man. 
