378 ANNUAL OF SCIENTIFIC DISCOVERY. 



and multiplied, perhaps still further modified, and the better sorts fixed by 

 selection and segregation. 



Keeping these principles in view, Mr. Yilmorin concluded that, in order to 

 obtain varieties of any particular sort, his first endeavor should be to elicit 

 variation in any direction whatever; that is, he selected his seed simply from 

 those individuals which differed most from the type of the species, however 

 unlike the state it was desired to originate. Repeating this in the second, 

 third, and the succeeding generations, the resulting plants were found to 

 have a tendency to vary widely, as was anticipated ; being loosed, as it were, 

 from the ancestral influence, which no longer acted upon a straight and 

 continuous line, but upon one broken and interrupted by the opposing action 

 of the immediate parents and grand-parents. Thus confused, as it were, by 

 the contrariety of its inherited tendencies, it is the more free to sport in vari- 

 ous ways ; and we have only to select those variations which manifest the 

 qualities desired, as the progenitors of the new race, and to develop and 

 fix the product by selection upon the same principle continued for several 

 generations. 



It is in this way that Mr. Yilmorin supposes cross-fertilization to operate 

 in the production of new A T arieties ; and even in the crossing of two distinct 

 species, the result, he thinks, is rarely, if ever, the production of a fertile 

 hybrid, but of an offspring which, thus powerfully impressed by the strange 

 fertilization, and rendered productive by the pollen of its own female parent, 

 is then most likely to give origin to a new race. 



We cannot follow out this interesting but rather recondite subject in a brief 

 article like this. But we are naturally led to inquire whether the history of 

 those plants with which man has had most to do, and the study of the laws 

 which regulate the production and perpetuation of domesticated races, may 

 not throw some light upon the production of varieties in nature; and 

 whether races may not have naturally originated, occasionally, under cir- 

 cumstances equivalent to artificial selection and segregation. Prof. Asa 

 Gray, Silliman's Journal, May 1859. 



