132 REVERSION, NOT A LAW, SUI GENERIS. 



upon the mere capacity of the assumption to explain 

 all of the facts. Proof, approximating demonstration, 

 is to be found in the chapters on Crossing and close- 

 interbreeding, where a crucial test is furnished, by 

 which it is possible ever, to ascertain, with respect to 

 organisms, whether the structure is complete, and 

 whether the coordination is of full integrity; or, how 

 far such structural integrity, and such full, normal coor- 

 dination have been departed from. Before proceeding 

 to develop this test, it is incumbent upon us to show 

 what a petitio principii, the argument from Natural Se- 

 lection (Darwin's potent factor) is. 



It is possible, also, to establish the similarity of the 

 Law of Generation, with that of Reversion. Genera- 

 tion is, equally, a process of repair. A portion of an 

 organism is exuded by an individual, and this portion 

 at once proceeds to complete, for itself, the type of the 

 given species. The reproductive element differs but 

 little, essentially, in its operation, from the part (spoken 

 of by Darwin), which is cut off from a Nais, or fresh- 

 water worm, and which then reproduces the whole. 

 The only difference lies in the manner in which the 

 parts are separated from the parent organism, and in 

 the necessity which, in some modes of Generation, 

 there is, that the reproductive element should be united 

 to that of the other sex. 



The point, sought to be illustrated, is, that every 

 mode of growth and of development (save that process 

 which controlled the evolution of the first member, or 

 members, of each species), is but a regain of the lost 

 integrity of the given species. 



