From whom did he get this idea that seeds or eggs are envelopes of all sorts of germs? It is not the "evolution" of a single germ, as, for example, an excessively minute but complete chick in the hen's egg, in the sense held by Bonnet. Who it was he does not mention. He evidently, however, had the Swiss biologist in mind, who held that all living things proceed from preëxisting germs.[113] Whatever may have been his views as to the germs in the egg before fertilization, we take it that he believed in the epigenetic development of the plant or animal after the seed or egg was once fertilized.[114] Lamarck did not adopt the encasement theory of Swammerdam and of Heller. We find nothing in Lamarck's writings opposed to epigenesis. The following passage, which bears on this subject, is translated from his _Mémoires de Physique_ (p. 250), where he contrasts the growth of organic bodies with that of minerals. "The body of this living being not having been formed by _juxtaposition_, as most mineral substances, that is to say, by the external and successive apposition of particles aggregated _en masse_ by attraction, but essentially formed by generation, in its principle, it has then grown by intussusception--namely, by the introduction, the transportation, and the internal apposition of molecules borne along and deposited between its parts; whence have resulted the successive developments of parts which compose the body of this living individual, and from which afterwards also result the repairs which preserve it during a limited time." Here, as elsewhere in his various works, Lamarck brings out the fact, for the first time stated, that all material things are either non-living or mineral, inorganic; or living, organic. A favorite phrase with him is living bodies, or, as we should say, organisms. He also is the first one to show that minerals increase by juxtaposition, while organisms grow by intussusception. No one would look in his writings for an idea or suggestion of the principle of differentiation of parts or organs as we now understand it, or for the idea of the physiological division of labor; these were reserved for the later periods of embryology and morphology. _Origin of the First Vital Function._--We will now return to the germ. After it had begun spontaneous existence, Lamarck proceeds to say: