THE CROSSING, 4C, OF PIGEONS AND FOWLS. 261 



bined in each individual; as a sine qua non of full, 

 functional integrity. The same good does not follow, 

 from crossing species (such as the common pigeon, 

 and the dove), because, as is obvious, there is not, in 

 such a case, an advance to a common, perfect type ; and, 

 because, in a hybrid, the characters of the two species, 

 are mixed together, in a manner, which precludes the 

 actual coordination from being impressed, in minia- 

 ture, upon the reproductive tissue ; as is done, where 

 the characters of the individual, belong to one and the 

 same species. 



With respect to this question, as it concerns the 

 Fowl, he says : x 



" In considering whether the domestic breeds (Fowl) 

 are descended from one species, namely, G. bankiva, 

 or from several, we must not overlook, though we 

 must not exaggerate, the influence of the test of fer- 

 tility. Most of our domestic breeds have been so 

 often crossed, and the mongrels are so largely kept, 

 that it is almost certain, that, if any degree of infer- 

 tility had existed among them, it would have been 

 detected. On the other hand, the four well-known 

 species of Gallus, when crossed with each other, or 

 when crossed, with the exception of G. bankiva, with 

 the domesticated Fowl, produce infertile hybrids. * * 

 The argument of fertility must go. for something.'' 



The address, with which this delicate subject is here 

 handled, would move the envy of Oily Gammon. Every 

 one knows, and Darwin clearly understands, that an 

 unanswerable objection to his theory, is the sterility of 

 hybrids, which imposes an effectual bar to his con- 

 founding- the species. Yet, with tact inimitable, he 



