274 HYBE1DISM. Chap. VIII. 



crossed with a third species, the hybrids are widely 

 different from each other ; whereas if two very distinct 

 varieties of one species are crossed with another species, 

 the hybrids do not differ much. But this conclusion, 

 as far as I can make out, is founded on a single experi- 

 ment ; and seems directly opposed to the results of 

 several experiments made by Kolreuter. 



These alone are the unimportant differences, which 

 Gartner is able to point out, between hybrid and 

 mongrel plants. On the other hand, the resemblance 

 in mongrels and in hybrids to their respective parents, 

 more especially in hybrids produced from nearly re- 

 lated species, follows according to Gartner the same 

 laws. When two species are crossed, one has some- 

 times a prepotent power of impressing its likeness 

 on the hybrid ; and so I believe it to be with varieties 

 of plants. With animals one variety certainly often has 

 this prepotent power over another variety. Hybrid 

 plants produced from a reciprocal cross, generally re- 

 semble each other closely ; and so it is with mongrels 

 from a reciprocal cross. Both hybrids and mongrels 

 can be reduced to either pure parent-form, by repeated 

 crosses in successive generations with either parent. 



These several remarks are apparently applicable to 

 animals ; but the subject is here excessively compli- 

 cated, partly owing to the existence of secondary sexual 

 characters ; but more especially owing to prepotency 

 in transmitting likeness running more strongly in one 

 sex than in the other, both when one species is crossed 

 with another, and when one variety is crossed with an- 

 other variety. For instance, I think those authors are 

 right, who maintain that the ass has a prepotent power 

 over the horse, so that both the mule and the hinny 

 more resemble the ass than the horse ; but that the 

 prepotency runs more strongly in the male-ass than in 



