HYBRIDS AND MONGRELS COMPARED 327 



HYBRIDS AND MONGRELS COMPARED, INDEPENDENTLY OF 

 THEIR FERTILITY 



Independently of the question of fertility, the offspring 

 of species and of varieties when crossed may be compared 

 in several other respects. Gartner, whose strong wish it was 

 to draw a distinct line between species and varieties, could 

 find very few, and, as it seems to me, quite unimportant dif- 

 ferences between the so-called hybrid offspring of species, 

 and the so-called mongrel offspring of varieties. And, on the 

 other hand, they agree most closely in many important re- 

 spects, 



I shall here discuss this subject with extreme brevity. The 

 most important distinction is, that in the first generation 

 mongrels are more variable than hybrids ; but Gartner admits 

 that hybrids from species which have long been cultivated are 

 often variable in the first generation ; and I have myself seen 

 striking instances of this fact. Gartner further admits that 

 hybrids between very closely allied species are more variable 

 than those from very distinct species ; and this shows that 

 the difference in the degree of variability graduates away. 

 When mongrels and the more fertile hybrids are propagated 

 for several generations, an extreme amount of variability in 

 the offspring in both cases is notorious ; but some few in- 

 stances of both hybrids and mongrels long retaining a uniform 

 character could be given. The variability, however, in the 

 successive generations of mongrels is, perhaps, greater than 

 in hybrids. 



This greater variability in mongrels than in hybrids does 

 not seem at all surprising. For the parents of mongrels 

 are varieties, and mostly domestic varieties (very few ex- 

 periments having been tried on natural varieties,) and this 

 implies that there has been recent variability, which would 

 often continue and would augment that arising from the act 

 of crossing. The slight variability of hybrids in the first 

 generation, in contrast with that in the succeeding genera- 

 tions, is a curious fact and deserves attention. For it bears 

 on the view which I have taken of one of the causes of 

 ordinary variability; namely, that the ;-eprodiictive system 

 from being emmently sensitive to changed conditions oi life, 



