Facts and Factors of Development

One of the greatest results of the doctrine of organic evolution has been the determination of man's place in nature. For many centuries it has been known that in bodily structures man is an animal—that he is born, nourished and developed, that he matures, reproduces and dies just as does the humblest animal or plant...

One of the greatest and most far-reaching themes which has ever occupied the minds of men is the problem of development...

The fact of development is everywhere apparent; its principal steps or stages are known for thousands of animals and plants; even the precise manner of development and its factors or causes are being successfully explored. Let us review some of the principal events in the development of animals, and particularly of man, and then consider some of the chief factors and processes of development.