Man's relation to anthropoid apes
The scientist is not concerned with this theory; he only claims that man is very closely related to certain monkey-like forms known as anthropoid apes. The proofs of this assertion are abundant and conclusive. In fact, anthropoid apes, such as gorillas, chimpanzees and orang-outangs, are much more closely related to man than they are to other kinds of monkeys. This relation is shown by very close resemblance between the anatomy of man and apes, especially as to the teeth and digestive organs. Other facts are now known, of which Darwin and early investigators were ignorant, which prove this relation in a much more striking manner.
Comparison of blood from man and apes
Late studies upon the growth of the embryo of anthropoid apes have shown that they were at certain periods almost indistinguishable from human embryos. Another proof, quite striking and interesting, is in the similarity of the parasites and dis-eases of men and apes. Scientists have, within the past few years, made a series of comparative investigations upon the blood and serum of men and apes, which have resulted in most remarkable discoveries. There are certain accurate tests known to the physiological chemist by which human blood may be distinguished from the blood of all other animals, but the blood of these man-like apes is an exception to this, and cannot be distinguished from human blood.
Difference in the development of man and apes
From these facts it is clear that the earlier types of men were creatures whose physical development and whose habits were not very different from those of apes. The development that has taken place since that time is truly very wonderful and has resulted in a widening gap between man and apes that today seems very great. The truth remains, however, that this gap is not so much one of anatomy and physiology as it is one of mentality and of external habits and material aids to living that have resulted from man's greatly developed mental faculties.
Power of speech a factor in man's evolution
Thus, when the mind of man reached the stage of development in which the use of articulate speech became possible, the evolution of intelligence proceeded at a very much more rapid pace than had been possible before. He could communicate his ideas to his fellow-creatures; concerted action became possible, and the faculty of reason, or the ability to think was multiplied by the number of beings who could communicate with each other.
The power of reason and the ability to communicate ideas resulted in the formation of those habits which distinguish man from other animals. When one primitive man learned the use of a club as a weapon, found how to use sharp-edged stones as cutting tools, or discovered the wonders and power of fire, he communicated his new-found knowledge to the other members of his tribe, with the result that new ideas became common property.