210 LOUIS AGASSIZ. [CHAP. xxm. 



Oken's "Natur-Philosophie," over fifty years ago, in which he claimed 

 that the key had been found to the whole system of organic life. . . . 



Darwin's watchwords, "natural selection," "struggle for exist- 

 ence," " survival of the fittest," are equally familiar to those who do, 

 and to those \vho do not, understand them ; as well known, indeed, 

 to the amateur in science as to the professional naturalist. His 

 theory is supported by a startling array of facts respecting the 

 changes animals undergo under domestication. . . . 



The final conclusion of the author is summed up in his theory of 

 Pangenesis. And yet this book does but prove more conclusively 

 what was already known ; namely, that all domesticated animals 

 and cultivated plants are traceable to distinct species, and that the 

 domesticated pigeons, which furnish so large a portion of the illus- 

 trations, are, notwithstanding their great diversity under special 

 treatment, no exception to this rule. The truth is, our domesticated 

 animals, with all their breeds and varieties, have never been traced 

 back to anything but their own species, nor have artificial varieties, 

 so far as we know, failed to revert to the wild stock when left to 

 themselves. Darwin's works and those of his followers have added 

 nothing new to our previous knowledge concerning the origin of man 

 and his associates in domestic life, the horse, the cow, the sheep, 

 the dog, or, indeed, of any animal. The facts upon which Darwin. 

 Wallace, Haeckcl, and others base their views are in the possession 

 of every well-educated naturalist. It is only a question of interpreta- 

 tion, not of discovery of new and unlooked-for information. . . . 



It has even been said that I have myself furnished the strongest 

 evidence of the transmutation theory. This might, perhaps, be so, 

 did these types follow, instead of preceding, the lower fishes. But 

 the whole history of geological succession shows us that the lowest 

 in structure is by no means necessarily the earliest in time, either in 

 the vertebrate type or any other. Synthetic and prophetic types 

 have accompanied the introduction of all the primary divisions of 

 the animal kingdom. With these may be found what I have callol 

 embryonic types, which never rise, even in their adult state. abo\ c 

 those conditions which in higher structures are but the prelude to 

 the adult state. It may. therefore, truly be said that a great variety 

 of types has existed from the beginning. . . . 



