XI PHENOMENA OF ORGANIC NATURE 401 



that although you have the same elements in the 

 experiment in each case, the offspring is entirely 

 different in character, according as the male influ- 

 ence comes from the ass or the horse. Where the 

 ass is the male, as in the case of the mule, you 

 find that the head is like that of the ass, that the 

 ears are long, the tail is tufted at the end, the feet 

 are small, and the voice is an unmistakable bray ; 

 these are all points of similarity to the ass ; but, 

 on the other hand, the barrel of the body and the 

 cut of the neck are much more like those of the 

 mare. Then, if you look at the hinny, the result 

 of the union of the stallion and the she-ass, then 

 you find it is the horse that has the predominance ; 

 that the head is more like that of the horse, the 

 ears are shorter, the legs coarser, an4 the type is 

 altogether altered ; while the voice, instead of being 

 a bray, is the ordinary neigh of the horse. Here, 

 you see, is a most curious thing : you take exactly 

 the same elements, ass and horse, but you combine 

 the sexes in a different manner, and the result is 

 modified accordingly. You have in this case, how- 

 ever, a result which is not general and universal 

 there is usually an important preponderance, but 

 not always on the same side. 



Here, then, is one intelligible, and, perhaps, 

 necessary cause of variation : the fact, that there 

 are two sexes sharing in the production of the off- 

 spring, and that the share taken by each is differ- 

 ent and variable, not only for each combination, 



