My theme is old; yet every topic into which heredity enters can now, in view of the recent advances in this study, be viewed in a new light. So possibly I may be able to present ideas in a new way.
Mental abnormality may be divided into two sorts: lack of development and weakness. Let us consider the origin of each sort. The development of an individual is a complex of processes which work individually to the production of specific organs, and collectively to the development of the individual as a whole. Modern studies in heredity indicate that, typically, each part develops to a certain extent independently of every other, at least in the early stages. Later the secretions of thyroid and thymus, testis and ovary, and doubtless other organs, exert a general or a specific influence on development. Finally, insufficient nutrition of the embryo or the presence of certain
DAVENPORT CB. HEREDITY IN NERVOUS DISEASE AND ITS SOCIAL BEARINGS. JAMA. 1912;LIX(24):2141-2145. doi:10.1001/jama.1912.04270120126013