162 STERILITY FROM 



Chap. XVIII. 



fertile as our geese in Europe. In the Philippine Archipelago the goose 

 it is asserted, will not breed or even lay eggs. 71 A more curious case is 

 that of the fowl, which, according to Koulin, when first introduced would not 

 breed at Cusco in Bolivia, but subsequently became quite fertile ; and the 

 English Game fowl, lately introduced, had not as yet arrived at its full 

 fertility, for to raise two or three chickens from a nest of eggs was thought 

 fortunate. In Europe close confinement has a marked effect on the 

 fertility of the fowl : it has been found in France that with fowls allowed 

 considerable freedom only twenty per cent, of the eggs failed; when 

 allowed less freedom forty per cent, failed ; and in close confinement sixty 

 out of the hundred were not hatched. 72 So we see that unnatural and 

 changed conditions of life produce some effect on the fertility of our most 

 thoroughly domesticated animals, in the same manner, though in a far 

 less degree, as with captive wild animals. 



It is by no means rare to find certain males and females which will not 

 breed together, though both are known ta be perfectly fertile with other 

 males and females. We have no reason to suppose that this is caused by 

 these animals having been subjected to any change in their habits of life ; 

 therefore such cases are hardly related to our present subject. The cause 

 apparently lies in an innate sexual incompatibility of the pair which are 

 matched. Several instances have been communicated to me by Mr. W. C. 

 Spooner (well known for his essay on Cross-breeding), by Mr. Eyton of 

 Eyton, by Mr. Wicksted and other breeders, and especially by Mr. Waring 

 of Chelsfield, in relation to horses, cattle, pigs, foxhounds, other dogs, and 

 pigeons. 73 In these cases, females, which either previously or subsequently 

 were proved to be fertile, failed to breed with certain males, with whom it 

 was particularly desired to match them. A change in the constitution of 

 the female may sometimes have occurred before she was put to the second 

 male ; but in other cases this explanation is hardly tenable, for a female, 

 known not to be barren, has been unsuccessfully paired seven or eight 

 times with the same male likewise known to be perfectly fertile. With 

 cart-mares, which sometimes will not breed with stallions of pure blood, 

 but subsequently have bred with cart-stallions, Mr. Spooner is inclined to 

 attribute the failure to the lesser sexual power of the race-horse. But I 



T , 



have heard from the greatest breeder of race-horses at the present da) 

 through Mr. Waring, that " it frequently occurs with a mare to be put 

 " several times during one or two seasons to a particular stallion of 

 " acknowledged power, and yet prove barren ; the mare afterwards 

 " breeding at once with some other horse." These facts are worth record- 

 ing, as they show, like so many previous facts, on what slight constitu- 

 tional differences the fertility of an animal often depends. 



7i Crawford's ' Descriptive Diet, of ix., 1862, pp. 380, 384. 

 the Indian Islands,' 1856, p. 145. 73 For pigeons, see Dr. Chapes, he 



7 2 * Bull, de la Soc. Acclimat.,' torn. Pigeon Voyageur Beige,' 1865, p. 66 - 









