It shews, I think, remarkable catholicity that the Eugenics Education Society should have invited me to deliver the Galton Lecture, inasmuch as though engaged in studies cognate with your own and of a kind which furnish some of the basic materials upon which the eugenist builds, I have never seen my way to take a definite part in its activities nor even to become a member of your body. In introduction I should like to explain the position which in common with several genetical colleagues both here and in the United States I have thought it best to maintain in this respect. Whoever is occupied with the practical investigation of genetic physiology can scarcely be out of sympathy with your objects. Witnessing, as such a man does every day of his life, the consequences of the working of the laws of heredity, the knowledge that the destinies of mankind are governed by the same laws is to him an all-pervading truth. Of this fact he needs no reminder. The course of heredity varies in detail with the organism and the characteristic under investigation, but the nature of the control which heredity exerts is the same in all living things. Every creature that has life arises by the division of a pre-existing cell, and the nature of the offspring will be determined by that of the parent until men gather grapes of thorns or figs of thistles.