Hybridization 127 



function of flowers; and we must concede that, as seed- 

 production decreased, floriferousness must have decreased ; 

 and that, therefore, pronounced inter-crossing would have 

 obliterated the very organs upon which it depends, or have 

 destroyed itself! 



In-breeding. But we may be met with objection that 

 there is no inherent reason why hybrids should not become 

 stable through seed-production by in-breeding, and we 

 might be cited to the opinion of Darwin and others that 

 in-breeding tends to fix any variety, whether it originates 

 by crossing or other means. And it is a fact that in- 

 breeding tends to fix varieties within certain limits, but 

 those limits are often overpassed in the case of very pro- 

 nounced crosses, whether cross-breeds or true hybrids. 

 And if it is true, as all observation and experiments show, 

 that sexual or reproductive powers of crosses are weakened 

 as the cross becomes more violent, we shall expect less and 

 less possibility of successful in-breeding; for in-breeding 

 without disastrous results is possible only with compara- 

 tively strong reproductive powers. As a matter of fact, 

 it is found in practice that it is exceedingly difficult to fix 

 pronounced hybrids by means of in-breeding. It some- 

 times happens, also, that the hybrid individual that we 

 wish to perpetuate may be infertile with itself, as has been 

 often found in the case of squashes. It is often advised 

 that we cross the hybrid individual which we wish to fix 

 with another like individual, or with one of its parents. 

 These results are often successful, but oftener they are not. 

 In the first place, it often happens that the hybrid individ- 

 uals may be so diverse that no two of them are alike; 

 this has been the experience in many cases. And, again 



