ABSTRACT
The development of humanity has taken place, like that of every form of life, amid the conditioning factors of its environment. Every phase of it and every aspect have oeen subject, as is organic evolution, to the determining influence of geographical and economic conditions. Some birds and rodents, as well as some of the lower monkeys, have a bigger brain, proportionally to their bodies, than man. In infant humanity that tendency, and the disposition to look to others for protection, assistance, and guidance, to require their approval and sympathy, were at least twice as strongly implanted. A man’s place in the scale of human evolution is not determined by the anatomical structure of his body, but by the social structure in which he develops. Normal human brains range roughly from 1200 to 1900 cubic centimetres in capacity. The human environment has grown to infinite complexity.
