ABSTRACT
ANYONE WHO has the honour of delivering the Galton Lecture has no shortage of topics to choose from, if he assumes that it is his duty to deal with a theme that had interested Francis Galton. In the amazingly wide range of subjects which aroused Galton’s curiosity, fertility took a prominent place, and so did mental disorder. But of the fertility of those who fell ill in this way, he did not write, as far as I know, and there has been relatively little attention given to the matter since his time: doubtless the volume of research and discussion would have been greater if there had been the initial stimulus of his ideas and inquiries. I should make it clear that I am excluding mental defect and dealing solely with mental disorders in this lecture.
