February. 1928 



EVOLUTION 



Page Five 



bicuspids. Yet, underlying the study of structure of 

 these teeth is the fact that the whole dental formula is 

 identical in all the forms examined, from Dryopithecus 

 to modern man — two incisors, one canine tooth, two 

 premolars and three molars on each side and in upper 

 and lower jaws. Likewise, the dental formula for the 

 milk teeth in all human races, all anthropoid apes and 

 fossil monkeys is identical. 



An amazing observation in connection with these teeth 



is that the crown patterns on the teeth of prehistoric 

 men and some of the primitive living tribes are nearer 

 the crown patterns found upon the fossil teeth of great- 

 grand-uncle Dryopithecus than upon the teeth of civil- 

 ized man. So far as teeth go, the Australian bushmen, 

 some of the remote African tribes and certain Indian 

 tribes are nearer the Old World apes than to you and me. 

 Considering the structure of teeth the gaps in the chain 

 of evidence are closed. There are no "missing links". 



How Man Differs From The Ape 



By Bernharu J. Stern 

 I. ANATOMICALLY 



IN 1860, when the Darwinian controversy was being 

 fought out in England, Thomas Huxley was asked by 

 Wilberforce, the Bishop of Oxford, whether "it was thru 

 his grandfather or his grandmother that he claimed his 

 descent from a monkey." Huxley's mordant answer is 

 now a classic: "I have asserted and I repeat that a man 

 has no reason to be ashamed of having an ape for his 

 grandfather. If there was an ancestor I should feel 

 ashamed of recalling, it would be rather a man, a man 

 of restless and versatile intellect, who not content with 

 success in his own sphere of activity, plunges into scien- 

 tific questions with which he has no real acquaintance, 

 only to obscure them with aimless rhetoric, and to dis- 

 tract the attention of his hearers from the real point at 

 issue by eloquent digressions and skilled appeals to 

 religious prejudice!" 



Were Huxley living today when we know more about 

 the relation between man and the apes, he would have 

 been all the more emphatic in his assertion that man has 

 no reason to be ashamed of having an ape for an ancestor, 

 or rather a relative. Man in his eagerness to rationalize 

 his own futility, and to compensate for his own short- 

 comings, usually exaggerates the differences between him- 

 self and his next of kin to the disadvantage of the apes. 

 In two articles, we shall analyze these differences, devot- 

 ing this article to anatomical differences and the second 

 to psychological differences. 



Much romantic nonsense has been written about the 

 importance of the structural differences between man and 

 apes. Drummond, for example, speaks of man alone as 

 having the ability to appreciate divinity because his pos- 

 ture permits him to raise his eyes from the ground to look 

 heavenward. We shall resist phantasy and devote our 

 attention to actual observable differences. 



Look at your hand. Move your thumb. Notice that it 

 can be swung toward or from any other finger; it is "op- 

 posable" as • ;anatomists say. This makes the hand 

 effective in holding and using tools. The thumb of an 

 anthropoid ape is much shorter than the human thumb 

 and it cannot be moved toward and from the other digits. 

 An ape therefore, finds it difficult, sometimes impossible, 

 to pick up a pin between his thumb and forefinger. When 

 he drops to the ground he walks on his knuckles and his 

 toelike thumb is useless. 



Gregory, Keith and McGregor point out, however, that 



this difference is functional rather than structural. 

 There are exactly the same number of fingers, exactly 

 the same number of bones in each finger, and the bones 

 are positioned in the same way. Even the fingers of the 

 hand move in the same way. Wiggle your fingers sep- 

 arately and in pairs and you will observe that III and 

 IV are paired and set off against II and V. Notice how 

 much easier it is to move III and IV together than II and 

 III. The tendons are arranged in the same manner in 

 the chimpanzee where the same pairing is found as in 

 the human hand. Furthermore, the embryologist, Schultz, 

 has shown that in the human embryo the thumb is not 

 opposable but is like that of a gorilla or chimpanzee, 

 a thumb that must become rotated to become human. 



Man's big toe, which is a powerful lever on which the 

 whole body can be raised and which is therefore a me- 

 chanical device for walking, is distinctively human, for 

 the big toe of the ape is not a toe at all but rather a 

 thumb. To convert the foot of a gorilla into that of a 

 man. Dr. Gregory has shown that the big toe must be 

 extended and rotated so that it rests flat on the ground 

 instead of facing the other toes. The bones of the toes 

 must be shortened and made to lie parallel so that the 

 foot is narrowed, and the foot must be turned to lie 

 down rather than in. Schultz has shown that this is 

 exactly what happens to the foot of the human embryo 

 in the course of its development. 



The difference between the brain of the anthropoid 

 and of man has been much discussed but recently Pro- 

 fessor Tilney has contended that the brain of the gorilla 

 is manlike in all fundamentals, and Dr. Smith has said 

 "No structure found in the brain of an ape is lacking 

 in the human brain, and on the other hand the human 

 brain reveals no formation of any sort that is not pres- 

 ent in the brain of the gorilla or chimpanzee. So far 

 as we can judge, the only distinctive feature of the 

 humati brain is a quantitative one, namely a marked 

 increase in the extent of three areas in the cerebral cor- 

 tex . . . which are relatively smaller in the brain of the 

 anthropoid apes." When it is realized that both literally 

 and figuratively nian uses only a very small fraction 

 of his brain matter, it will be recognized that this differ- 

 ence is not as important as is commonly assumed. 



Next month: How Man Differs from the Ape: Psy- 

 chologically. 



