the half-century that has passed since this conversation, the feeling of the unity of science has advanced, and to how great a degree it has entered into the intimate convictions of the most learned men, does not need to be told.
At a time when all students are avowing themselves bonded in the universality of science, the speaker who is called upon to discuss the subject finds himself in the face of an audience whom he has nothing to teach, but from whom he has much to learn.
A natural inclination leads him to consult, first, the biologists, who have probed to the earliest manifestations of life on our planet; and he is seized with wonder at finding that paleontology, emancipated from the curious contemplation of extinct organisms, has risen to phylogeny, and is following in the host of vital forms that order of evolutionary succession which causes the most recent beings to be regarded as the descendants and heirs of their predecessors. Biological paleontology judges the law of successive evolution to be immanent in the development of species and of individuals. It discovers that the development of the most perfect beings on the earth is made after the form of the generations which preceded those elevated organisms, in such a way that every example of ontogenic evolution appears to be a rapid summary of the phylogenic evolution that preceded the appearance of the being the embryology of which is studied.
Every organized form is fitted in as an essential link in a chain of derivation and descent. Nothing is now left of that fancy that saw in the plan of Nature a mass of accidental variations, like the caprice of an author who published at the same time with his finished works all of his rough draughts and printers' proofs.
At the point we have reached, natural history, regarded as biogeny, can not do without paleontology. Zoölogy affirms that there ought to be transitional forms between reptiles and birds, which present many points of contact and traits of fundamental analogy; but such forms are not found among the beings of our age. Paleontology, however, shows that in the secondary or mesozoic age there lived reptiles having the form of birds, and birds having the form of reptiles.
Just as the paleontologist has taken his place among biologists by investigating the characters of successive developments and discovering and reconstructing the relationships of extinct organisms, so the archaeologist has, through ethnography and ethnology, without perceiving it, entered the same camp.
It is the same with whatever relates to civilization. Sometimes the parts are reversed. The linguist asks the physiologist to investigate the laws of phonation and to study accents, analyze the quality of the sound of the vowels, and the sounds that correspond with each consonant, among different races and in different prov-
