M. Naudin, as we see, in order to support his theory, appeals to the embryogenic phenomena, to which the Darwinists also look for testimony in favour of their doctrines. The learned botanist, however, attaches much more importance to the metamorphoses which take place subsequently to the egg. He recognises _true proto-organisms_ in the pro-embryo of mosses, in the larvæ of insects, and of many other inferior animals. He lays particular stress upon the phenomena of alternate generation, as representing what has already taken place, or better, as representing in part “the ancient and general process of creation.” According to M. Naudin, man was subject to the common law, and the Mosaic account is at the same time very true and full of instruction. In its first phase, mankind was concealed within a temporary organism, already distinct from all others, and incapable of contracting an alliance with any of them. This is Adam, who sprang from a primordial blastema called _clay_ in the Bible. At this epoch, he was, properly speaking, neither male nor female; the two sexes were not yet differentiated. “It is from this larval form of mankind, that the evolutive force effected the completion of the species. For the accomplishment of this great phenomenon, Adam had to pass through a phase of immobility and unconsciousness, very analogous to the nymphal state of animals undergoing metamorphosis.” This is the sleep mentioned in the Bible, during which the work of differentiation was accomplished, to use the words of M. Naudin, by a process of germination, similar to that of medusæ and ascidians. Mankind, thus constituted physiologically, would retain a sufficient evolutive force for the rapid production of the various great human races. Passing over the comparisons established by M. Naudin, I will confine myself to a single observation upon all these ideas; properly speaking, they do not form a _scientific theory_. When we fertilise by artificial means the egg of a frog, we know that we determine an entire series of phenomena, which results in the formation of a germ, then in that of an embryo, which will be established by a succession of metamorphoses, in that of a tadpole, which will be equally subject to metamorphoses, and in that of a definite animal which will assume all the characters of the species. So far as man can _make a being_, we _make a frog_ when we fertilise an egg.