"I agree with Geoffrey Saint Hilaire, that often a great analogy is observed between the final state of certain parts of the bodies of some inferior animals, and the embryonic state of the same parts of other animals belonging to the same type the organism of which is further developed, and with the same philosopher, I call the cause of the state of permanent inferiority arrests of development. But I am far from thinking with some of his disciples that the embryo of man or of mammals exhibits in its different degrees of formation the species of the less perfect of animate creation. No! a {76} mollusk or an anhelid is not the embryo of a mammal, arrested in its organic development, any more than the mammal is a kind of fish perfected. Each animal carries within itself, from the very origin, the beginning of its specific individuality, and the development of its organism, in conformity to the general outline of the plan of structure proper to its species, is always a condition of its existence. There is never a complete likeness between an adult animal and the embryo of another, between one of its organs and the transitory state of the same in the course of formation; and the multiplicity of the products of creation could never be explained by a similar transmutation of species. We shall see hereafter, that in every zoological group composed of animals which seem to be derived from a common fundamental type, the different species do not exhibit at first any marked difference, but soon begin to be marked by various particularities of constructure always growing and numerous. Thus each species acquires a character of its own, which distinguishes it from all others in the way of development, and each of its organs becomes different from the analogous part of every other embryo. But the changes which the organs and the whole being undergo after they have deviated from the common genesiac form, are generally speaking the less considerable in proportion as the animal is destined to receive a less perfect organism, and consequently they retain a kind of resemblance to those transitory forms." Reason then and experience, theory and fact, philosophy and physiology, agree in protesting against the arbitrary doctrine of the unity of type in the animal kingdom; a doctrine which has its origin in an absence of sound scientific notions and a superficial observation of the phenomena of nature. Through the former defect men failed to consider that if the end of each animal species is different, different also must be its being, and therefore a different type must preside as a rule and supreme law over the formation of the being. By the latter, some very slight and partial analogies have been mistaken for identity and universality, and mere appearances have been assumed as realities. ---- From Blackwood's Magazine. DOMINE, QUO VADIS? [Footnote 6] BY P. S. WORSLEY.