EVOLUTION
667
EVOLUTION
analogies of structure and function in vastly different brain with all its convolutions and that of the orang
groups. Finally, the chief problem, which refers to
teleology of adaptive modifications, is not even touched
by the doctrine of descent from common ancestors.
(2) Man and the Anthropoids. — Paheontology
knows of no records that point to the relationship be-
tween the body of man and that of the anthropoid.
Hence it follows that the argument of analogy and
classification is of little worth. But, as ever and again
attempts are made to discover analogies between
every bone of man and the corresponding part of the
ape (e. g. Wiedersheim). it will be useful to gather a
few of the more important morphological discrepan-
cies which exist between man's body and that of the
anthropoids (orang-utang, chimpanzee, gorilla). It
is, however, far from our intention to attribute to
these differences any great argumentative force, espe-
cially against those who suppose that there was a com-
mon primeval ancestor from which both man and ape
finally descend; nor do we wish to deny that zoologi-
cally the human body belongs to the class of the mam-
malia, nor that within this class there is any repre-
sentative more similar to it than tlie anthropoids.
Of these differences the most important lies in the development of the brain of man and of the anthro- poid, which is seen from the comparison of the weights, .\ccording to Wiedersheim we are forced to jidmit that the relative mass of the human brain is twice that of the chimpanzee, while, alwolutely, it i.s from three to four times as great. The same is prol>- ably true of the orang-utang. while the brain of the gorilla, which, according to Wiedersheim, i,s the most humanlike of any of the aiitliropoid lirains, is rela- tively only one-fifth that of man's. The human skull is from three to four times as large as that of the an- thropoids. The difference becomes much more strik- ing still when wecompare the cerebral hemispheres and their convolutions. The weight of the brain of a male Teuton of from thirty to forty years of age i.s on the average 14'2 1 grammes, that of a female 127:i grammes, and that of a full-grown orang only 79-7 grammes (Wundt). The proportion is therefore from 1S:1 to 16:1. If we measure the superficial area of man's
we have, according to Wagner, from 1877 sq. cm. to
2196 sq. cm. for the human brain and 533-5 sq. cm. for
that of the orang — that is a proportion of 44:1. It is
further to be taken into consideration that, as Wieder-
sheim points out, the hiunan brain is not to be looked
upon as an enlarged anthropoidal one, hut as a " new
acquisition with structures which the anthropoidal
does not as yet [!] possess". These new acquisitions
are presumably qualitative and refer mainly to the
centre within the gi-eat cerebral hemispheres. Inti-
mately connected with the development of the brain
is the moderate development of the dentition of man
in comparison with the chinless snout of the monkey,
which is armed with powerful teeth. Again, "the
human face slides as it were down from the forehead
and appears as an appendix to the front half of the
skull. The gorilla's face, on the contrary, protrudes
from the skull, which on return slides almost entirely
backwards from the face. ... It is only on account
of its protruding, strongly developed lower parts that
the small skull-cap of the animal can mask as a kind of
human face" (Ranke).
A second group of differences is obtained by com- paring the limbs of man and the anthropoid. Owing to his upright stature, man's appendicular skeleton is quite different in form and structure from that of the anthropoid. This is shown not merely by the length of the single parts, which, strangely enough, exhibit inverse proportions, but also in the interior structure of the bones, as was proved l)y Walkhoff (1905) in the case of the femur. If we suppose the length of the body to be 100 we have, according to Ranke, the fol- lowing proportions: —
Part iCorillal Chimpanzee
Orang Negro
German
Arm and hand
Leg
64-9
319
677
352
807
34-7
4516
4S-.5
45-43
48-8
Special measurements taken from the skeletons of
an adult Frenchman and an orang, represented in
the accompanying plate, gave the following par-
ticulars: —
