HO PRINCIPLES OF STOCK-BREEDING. 



breed, in the Zoological Gardens, within a year or two 

 after their first importation,' 5 and he adds that, " when 

 an animal which is generally sterile under confinement 

 happens to breed, the young apparently do not inherit 

 this power, for, had this been the case, various quad- 

 rupeds and birds, which are valuable for exhibition, 

 would have become common." * 



" The carnivora in the Zoological Gardens were 

 formerly less freely exposed to the air and cold than 

 at present ; and this change of treatment, as I was as- 

 sured by the former superintendant, Mr. Miller, great- 

 ly increased their fertility." a 



From the preceding statements it might be in- 

 ferred that the state of domestication was not favor- 

 able to fertility; but we find, nevertheless, that do- 

 mesticated varieties are more prolific than wild species. 

 Tame geese and ducks lay many more eggs than wild 

 ones. Dogs have a larger number of young at a birth 

 than their wild cousins, the wolf and the fox. 



The tame varieties of swine are more prolific than 

 wild species. " The wild rabbit is said generally to 

 breed four times yearly, and to produce from four to 

 eight young; the tame rabbit breeds six or seven 

 times yearly, and produces from four to eleven young." 



Wild pigeons do not breed so often as tame varie- 

 ties, and Macgillivray states that, while the wild rock- 

 pigeon breeds but twice a year. " the same pair, when 

 tamed, generally breed four times." ' 



1 Loc. cit., p. 195. 

 9 Ibid., p. 185. 



3 " Principles of Biology," vol. ii., p. 457 ; " Animals and Plants 

 under Domestication," vol. ii., p. 139. 



