FECUNDITY. 109 



and living long, in the south of France never lays 

 more than from twelve to fifteen eggs, though in its 

 native country it lays from twenty-five to thirty." l 



Lord Somerville says the Spanish merino sheep, 

 in England, when first imported, had a tendency to 

 barrenness and " there was a great deficiency of milk 

 in the ewes," 2 which he attributes to the severe jour- 

 neys the sheep were accustomed to make in Spain. 

 As a deficiency in the secretion of milk and a ten- 

 dency to barrenness have not been observed in these 

 sheep when removed to other countries, these defects 

 in England must have been owing to a change in the 

 conditions of life, rather than to a previous habit of 

 the system. 



According to M. Roulin, " in the hot valleys of 

 the equatorial Cordilleras, sheep are not fully fecund," 

 and geese, taken to the lofty plateau of Bogota, did 

 not at first breed well. 8 



Mr. Darwin says : " In Europe close confinement 

 has a marked effect on the fertility of the fowl : it has 

 been found in France that, with fowls allowed con- 

 siderable 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." 4 



Mr. Darwin was assured that " those animals 

 which usually breed freely under confinement, rarely 



1 Darwin, loc. cit, p. 191. 



9 Somerville's " Facts and Observations," p. 14 ; quoted in Youatt 

 on "Sheep," p. 181. 



3 " Animals and Plants under Domestication," vol. ii., p. 197. 



4 Loc. '/., p. 198. 



