$2O Edward Livingston Youmans. 



The article Progress, its Law and Cause, projected, as 

 we have seen, in 1854, was written early in 1857. In the 

 first half of it the transformation of the homogeneous into 

 the heterogeneous is traced throughout all orders of phe- 

 nomena ; in the second half the principle of transformation 

 is deduced from the law of the multiplication of effects. 

 In this essay, moreover, there is indicated the application 

 of the general law of Evolution to the production of 

 species. It is shown that there " would not be a substitu- 

 tion of a thousand more or less modified species, for the 

 thousand original species ; but, in place of the thousand 

 modified species, there would arise several thousand species 

 or varieties or changed forms " ; and that " each original 

 race of organisms would become the root from which 

 diverged several races differing more or less from it and 

 from each other." It is further argued that the new rela- 

 tions in which animals would be placed toward one another 

 would initiate further differences of habit and consequent 

 modifications, and that " there must arise, not simply a tend- 

 ency toward the differentiations of each race of organisms 

 .into several races, but also a tendency to the occasional 

 production of a somewhat higher organism." The case of 

 the divergent varieties of man, some of them higher than 

 others, caused in this same manner, is given in illustration. 

 Throughout the argument there is a tacit implication that, 

 as a consequence of the cause of Evolution, the production 

 of species will go on, not in ascending linear series but by 

 perpetual divergence and redivergence branching and 

 again branching. The general conception, however, differs 

 from that of Mr. Darwin in this ; that adaptation and re- 

 adaptation to continually changing conditions is the only 

 process recognized there is no recognition of " sponta- 

 neous variations," and the natural selection of those that 

 are favourable. 



During the summer of 1857 Mr. Spencer wrote the 



