THE UNITY OF SCIENCE. 521 



the half-century that has passed since this conversation, the feel- 

 ing 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 dis- 

 cuss 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 paleon- 

 tology, 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 genera- 

 tions which preceded those elevated organisms, in such a way that 

 every example of ontogenic evolution apj)ears to be a rapid sum- 

 mary 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. Zoology 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 organ- 

 isms, 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 in- 

 vestigate 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- 



