The conception of endocrine diversity in the make-up supplies us with the rationale of the vast majority of organic and functional defects and inferiorities, in short, subnormalities of any group, large or small.

To explain the subnormality, the criminologist has conducted and will continue to conduct investigations into the heredity and early environment of the criminal, his education and occupation, the social and religious influences to which he was subjected, and the intelligence test quotient.

Without close examination and thorough tests, illiteracy generally passes as subnormality.