cerebral convolutions of man and apes; and as the purpose of my learned
colleague was certainly not to diminish the value of the differences
between apes and men in this respect, I am glad to make a citation from
him.
That the apes, and especially the orang, chimpanzee and gorilla, come
very close to man in their organisation, much nearer than to any other
animal, is a well known fact, disputed by nobody. Looking at the matter
from the point of view of organisation alone, no one probably would
ever have disputed the view of Linnaeus, that man should be placed,
merely as a peculiar species, at the head of the mammalia and of those
apes. Both shew, in all their organs, so close an affinity, that the
most exact anatomical investigation is needed in order to demonstrate
those differences which really exist. So it is with the brains. The
brains of man, the orang, the chimpanzee, the gorilla, in spite of all
the important differences which they present, come very close to one
another (loc. cit. p. 101).
There remains, then, no dispute as to the resemblance in fundamental
characters, between the ape s brain and man s: nor any as to the
wonderfully close similarity between the chimpanzee, orang and man, in
even the details of the arrangement of the gyri and sulci of the
cerebral hemispheres. Nor, turning to the differences between the
brains of the highest apes and that of man, is there any serious
question as to the nature and extent of these differences. It is
admitted that the man s cerebral hemispheres are absolutely and
relatively larger than those of the orang and chimpanzee; that his
frontal lobes are less excavated by the upward protrusion of the roof
of the orbits; that his gyri and sulci are, as a rule, less
symmetrically disposed, and present a greater number of secondary
plications. And it is admitted that, as a rule, in man, the
temporo-occipital or external perpendicular fissure, which is usually
so strongly marked a feature of the ape s brain is but faintly marked.
But it is also clear, that none of these differences constitutes a
sharp demarcation between the man s and the ape s brain. In respect to
the external perpendicular fissure of Gratiolet, in the human brain for
instance, Professor Turner remarks: (71. Convolutions of the Human
Cerebrum Topographically Considered, 1866, p. 12.)
In some brains it appears simply as an indentation of the margin of
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