16 THE ORIGIN OF SPECIES 



for I am assured by two eminently capable judges, 

 namely, Mr. Blyth and Capt. Ilutton, that whole flocks 

 of these crossed geese are kept in various parts of the 

 country; and as they are kept for profit, where neither 

 pure parent-species exists, they must certainly be highly 

 or perfectly fertile. 



With our domesticated animals, the various races when 

 crossed together are quite fertile; yet in many cases they 

 are descended from- two or more wild species. From this 

 fact we must conclude either that the aboriginal parent- 

 species at first produced perfectly fertile hybrids, or that 

 the hybrids subsequently reared under domestication be- 

 cam ^ quite fertile. This latter alternative, which was first 

 propounded by Pallas, seems by far the most probable, 

 and can, indeed, hardly be doubted. It is, for instance, 

 almost certain that our dogs are descended from several 

 wild stocks; yet, with perhaps the exception of certain 

 indigenous domestic dogs of South America, all are quite 

 fertile together; but analogy makes me greatly doubt 

 whether the several aboriginal species would at first have 

 freely bred together and have produced quite fertile 

 hybrids. So again I have lately acquired decisive evi- 

 dence that the crossed offspring from the Indian humped 

 and common cattle are inter se perfectly fertile; and from 

 the observations by Riitimeyer on their important osteo- 

 logical differences, as well as from those by Mr. Blyth 

 on their differences in habits, voice, constitution, etc., 

 these two forms must be regarded as good and distinct 

 species. The same remarks may be extended to the two 

 chief races of the pig. We must, therefore, either give 

 up the belief of the universal sterility of species when 

 crossed; or we must look at this sterility in animals, not 



