162 EXPERIMENTAL EVOLUTION LECT- 



As Cornevin l remarks, some essential conditions must 

 be fulfilled before any species can be domesticated. 

 The principal requirements are the following : 



First, Sociability. All domestic animals, as observa- 

 tion at once shows, live in societies, in herds all, save 

 one, the cat ; the much-abused cat, the much-praised 

 cat, the most independent and self-centred of our 

 domestic friends. This gregariousness of all our do- 

 mestic mammals and birds, pigeon or fowl, hog or 

 ox, shows that if we are to attempt new domestica- 

 tions we must direct our attention towards gregarious 

 animals. 



Secondly, Tameness. Only docile animals can be 

 domesticated, and all animals cannot be tamed with 

 the same facility. Some retain a very considerable 

 element of savageness, whatever care may be taken 

 to tame them. Tameness is the result of kind treat- 

 ment, and of the habit of being constantly with man, 

 and while some species seem untamable, the greater 

 proportion may be more or less tamed. 



Thirdly, Preservation of Fertility. Many animals, 

 even in their own country, become sterile under 

 domestication or captivity ; they have no progeny, 

 or but a very small one. It also often happens 

 that the transfer to a new country induces temporary 

 decrease of fertility. The common fowl when intro- 



1 Traite de Zoolechnie generate, 1891. 



