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indicated by natural selection, z. e., through variations in the most advantageous direction for the preservation of the organ- ism in its relations with the climatic and alimentary environment, etc. It becomes definitely a veritable phenomenon, not indi- vidual, but collective and social. Weismann has not sufficiently noticed that the difference between his doctrine and that of Darwin and Spencer is not so radical in its results as he thinks.
The variability of organisms, so far as it results from that which precedes, is therefore limited at each moment of time by the very nature of the organisms and by the conditions of the environment. Variability never preponderates, even in the interpretation of Weismann, over the conservative and co-ordi- native function of continuity; i. e., for short, over heredity. In the active substance of the germinal plasm there is always a part which remains unmodified and fixed, when the germ is developed into an organism. This more or less considerable residue serves as a bond between the past, present, and future. It furnishes the basis of the germinal cells of the new organism, and thus one after another of all those which shall follow. There is therefore uninterrupted continuity of the germinal plasm from one generation to another. This continued transmission of the ancestral germ constitutes the function of heredity. There are, therefore, order, fixity, persistence, and continuity in variability itself. This explains the remarkable persistence of the social and organic types. Their fundamental structure is a heritage. The germ of this structure is itself the product of a long natural selection which is fixed, and which neither the environment nor the will can modify in an absolute fashion, although theoretically, or rather from the standpoint of the purely rational and negative critic, the bases of this structure should be considered false. 1 Weismann explains this persistence of heredity in the following passage :
The physical constitution of the species depends upon the ensemble of hereditary characteristics adapted to each other and so combined as to form a harmonious whole. It is this peculiar nature of the organism which per-
"Some disharmonies presented by the learned ELIE METCHNIHOFF in his inter- esting work, La nature humaine (Paris, 1903), are striking illustrations of the theories of Weismann relating to selection and heredity.
