268 THE CROSSING, &C, OF PIGEONS AND FOWLS. 



requests his readers not to overlook (sic) the facts 

 upon which the said objection is based ! and gravely 

 assures them that " the argument of fertility must go for 

 something." Solicitous, however, lest his injunction, 

 not to overlook the question of fertility, should be 

 too fully complied with, he, with an air, exquisitely 

 judicial, guards them, carefully, from running upon 

 Gharybdis, by warning them, that they " must not ex- 

 aggerate the influence of the test of fertility." The 

 state of mind, which is occasioned, in his readers, by 

 this dexterous treatment of a witching point, is such, 

 that they wholly waive the impression, by them first 

 entertained; suffer vague doubts, respecting the validity 

 of the objection, to enter their minds; modestly dis- 

 trust their own capacity to gauge the question ; and, 

 end by fancying, that they owe a debt of gratitude to 

 Darwin, for kindly arresting them, when they were on 

 the very verge of metaphysics — which, an English- 

 man ever affects to regard, as his bete noir. 



"The argument of fertility" does "go for some- 

 thing." What it "goes for," is, that the varieties are 

 not "incipient" species; and, that they are physiologi- 

 cally incompetent to become distinct species : for, the 

 individuals composing these divergent varieties lose 

 their fertility, when bred among themselves, and ap- 

 proximate perfect fertility, only when crossed with in- 

 dividuals of a separate variety; whereas, species are 

 notable, for having their respective individuals fertile, 

 inter se, and sterile, when crossed with individuals of 

 other species. Verily, "the argument of fertility must 

 go for something;" but, it is refreshing, here to see 



