The science of life : fully illustrated in tone and line and including many diagrams

THE SCIENCE OF LIFE

Fig. 151.

CHAPTER 5

Orang-outangs, young and old, drawn from ltfe. At home in the family circle ; mother transporting her baby ; young hopeful resting, and hanging by one leg.

Lower right,

an old male of the variety which has a fleshy fold round the face in place of whiskers.

face and expression are all but human. In a number of points the chimpanzee or the gorilla differ more from the other great apes than they do from man. It used to be asserted that there existed definite structures in man’s anatomy, especially in his brain, which were absent in apes. T. H. Huxley, as far back as 1863, demonstrated in his classical essay, Man's Place in Nature, that this was not true. The differences between human structures and ape structures are only differences of degree. Man’s brain and brain-case are proportionately larger ; but, as Elliot Smith has shown us, this increase is due to the enlargement of parts of the brain already present in the ape—the parts concerned primarily with the faculty of association—and no brainorgans are to be found in man which are not also to be found in apes. ‘The dog-teeth of us men are smaller, and so are our big toes, but our thumbs and chins are larger. We have adopted the upright position, and our anatomy shows minor changes as a result. Our legs are straighter than apes’; our spinal cord is bent in a different way ; our pelvis, besides still affording attachment to dozens of muscles, has been turned into a flat basin which supports the internal organs

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of our abdomen; a new development of the gluteal muscles is needed to hold us upright, with the result that our “lower back” protrudes in a way unknown among animal buttocks ; our head is poised on a straight pillar of a neck, instead of protruding forward. Our jaws and the bony ridges over our eyes are smaller, our noses and chins larger. Apart from brain-size, the reduced amount and length of hair on the human body and the less hand-like construction of the human foot are perhaps the most obvious differences between man and ape, but even they are only differences in proportions and amounts, no whole structures being gained or lost or transformed into something radically new.

And when we come to behaviour and the mind at the back of behaviour, the chimpanzee is far more like a man than like a frog. To begin with, the actual raw material of an ape’s experience, the data provided by its senses, differ from a frog’s but resemble our own in many points. The frog lives in a world of black and white ; apes, like us, in one enriched with colour. The apes, like us, have a “ yellow spot” in their eyes, making them capable of exceptionally accurate vision ; the power of discrimination in a