It is impossible, however, to form a conception of what may be regarded as an ideal type of the human species.

The type which might be ideal in a certain environment might not be ideal in another, and environment is probably of equal importance with the material.

The eugenics movement has enormously stimulated research into heredity by the methods both of animal experimentation and observation, and study of heredity in man.

As in all of the beginning sciences there is not the close inter-relation of observed facts and theory, but there is excess of theory and dearth of facts.

Certain considerations, however, seem to be evident.