ON THE RELATIONS OF MAN WITH THE LOWER ANIMALS 487 
plex, and those of the two cerebral hemispheres are more symmetrical, 
than in man. 
4. The hemispheres are more rounded and deeper in man than in 
the anthropoid apes, and the proportions of the lobes to one another 
are different. Furthermore, certain minor gyri and fissures, present 
in the one, are absent or rudimentary in the other. 
The evidence of the first of these differences has, I believe, been uni- 
versally admitted since the time of Semmering. The second and fourth 
clearly result from the observations of Schroeder van der Kolk and 
Vrolik, and those of Gratiolet (Mem. sur les plis cerebraux des Primates, 
1854), as will appear from the following extracts. The first citation is 
taken from the work of the first-named authors, which seems to be so 
little known in this country, that I make no apology for length of the 
extract :— 
“ According to very precise investigations which the first-named of 
us has carried out with reference to this point, the difference between 
the brains of the higher apes and that of man is to be sought, not only 
in the smaller size of the hemispheres, but also in a totally different 
relation of the lobes. Relatively, the under surface of the first lobe of 
the cerebrum, in the chimpanzee, is much larger than in man; while, on 
the other hand, the distance from the most anterior point of the middle 
lobe to the hindermost point of the posterior lobe is much smaller. In 
our chimpanzee the distance from the root of the olfactory nerve to 
the anterior margin of the brain is about 44 millimetres, from the 
point of the middle lobe to the extreme end of the posterior lobe, 69 
mm. In the adult man, according to measurements which the first of 
us has instituted, and which wholly agree with those of the ninth plate 
of Foville, the first named measurement is 57 mm., the second, 145 
mm. In the brain of a new-born child, examined by us, the first 
dimension amounted to 33 mm., the second to 7omm. The length of 
the base of the anterior lobe was thus to the distance from the point 
of the middle lobe to the end of the posterior lobe, in the chimpanzee, 
as 1: 1°52; in the adult man as I : 2°54; in the child,as 1:2. Hence 
it appears that the relative proportions of the lobes of the child’s brain 
hold just the mean between the chimpanzee and the adult man ; and 
that in the course of the growth of the child to manhood, the posterior 
and middle lobes increase more in length than the base of the anterior 
lobe. In the orang, the same proportion obtains as in the new-born 
child, or 1 : 2, a result which is certainly remarkable, and proves that, 
in this respect, the brain of the orang stands higher than that of the 
chimpanzee. The second point to which we would direct attention is, 
that in comparing the brain of man with that of animals, and especially 
