before he can assume the characters belonging to his species. An eminent professor has recently expressed these views in a concise form, saying that the embryology of the most perfect being is a comparative transitory anatomy, and that the anatomic table of the whole animal kingdom is a fixed and permanent representation of the movable aspect of human organogeny." Thus, according to this opinion, man is the only type of animal life; and every inferior species is but an imitation, more or less perfect, of the same; an inchoation stopped in its course at a greater or shorter distance from the term to which the work of nature tends in its organization of the human embryo. In short, an {72} _entoma in difetto_, to use the language of Dante. The doctrine is not new in the scientific world. It was proclaimed in the last century by Robinet, who held that all inferior beings are but so many proofs or sketches upon which nature practises in order to learn how to form man. In the beginning of the present century Lamarck, in Germany, following Kielmayer, reproduced the same theory. According to him all the species of animals inferior to man are but so many lower steps at which the human embryo stops in its gradual development. Man, on the contrary, is the last term reached by nature after she has travelled all through the zoological scale, to fit herself for that work. About the same time the celebrated naturalist, Stephen Geoffroy Saint Hilaire, began to disseminate in France analogous ideas under the name of _stages of development_ (_arrêt de devéloppement)_; and these ideas, exaggerated by some of his disciples, amounted in their minds to the same doctrine of Lamarck, just alluded to. Among them Professor Serres holds the first rank, and it is to him that Milne-Edwards alludes in the passage just cited. He expresses himself thus: