CHAPTER XI 

 HYBRIDS 



THE subject treated in this and the next chapter 

 is one of the most interesting to mankind, and is 

 surrounded by extraordinary prejudice, sentiment, 

 and ignorance. It is one upon which really trustworthy 

 information is to a very large extent absent and difficult 

 to obtain. I cannot profess to supply this deficiency, but 

 I can put the matter before the reader. 



It is a well-established fact that the various " kinds " 

 of animals and of plants do not breed promiscuously with 

 one another. The individuals of a " species " only breed 

 with other individuals of that " species." They do not even, 

 as a habit, breed with the individuals of an allied species. 

 So nearly universal is this rule that it was for a long 

 time held by naturalists to be an absolute definition of 

 " a species," that it is a group of individuals capable of 

 producing fertile young by breeding with one another 

 and incapable of producing fertile young by mating with 

 individuals of another such group, which were, therefore, 

 held to constitute a distinct species. The practical im- 

 portance of this definition was that it could, in a large 

 number of instances among animals, and still more 

 amongst plants, be made use of as a test and decided 

 by experiment. 



It is a curious fact that popular belief amongst 

 country-folk and those who have opportunities of coming 

 to a conclusion on so simple and direct a question has 



