268 THE GENESIS OF SPECIES. [CiiAr. 



cliaracters loii;^" inlierited, as the grandcliildreii of Ayles- 

 biny ducks, removed to a distant part of England, cuiii- 

 plettdy lost tlicir early habit of incubation, and hatched 

 their eLjijs at the same time Avitli the common ducks of the 

 same place." ^ 



Mr. l)anvin ([uotes Mr. Bartlett as saying :" Tt is re- 

 markable that lions breed more freely in travelling collec- 

 tions than in the zoological gardens ; probably the constant 

 excitement and irritation produced by moving from place 

 to place, or change of air, may have considerable inlluence 

 in the matter.'*^ 



Mr. Darwin also says : " There is reason to believe that 

 insects are affected by confinement like the higher animals," 

 and he gives examples.^ 



Again, he gives examples of change of plumage in. the 

 linnet, bunting, oriole, and other birds, and of the temporary 

 modification of the horns of a male deer during a voyage.* 



Finally, he adds that these changes cannot be attributed 

 to loss of health or vigour, " when we reflect how healthy, 

 long-lived, and vigorous many animals are under cap- 

 tivity, such as parrots, and hawks when used for hawking, 

 chetahs when used for hunting, and elephants. Tlie re- 

 productive organs themselves are not diseased ; and the 

 diseases from which animals in menageries usually perish 

 are not those which in anv wav affect their feililitv. No 

 domestic animal is more subject to disease than the sheep, 



yet it is remarkably prolific Tt would appear that 



any change in the habits of life, whatever these haljits 

 may be, if great enough, tends to affect in an inexi)licable 

 manner the powers of reproduction." 



' " Animals auJ Plants umlcr Domestication," vol. ii. [•. 2.5. 

 - ll.i.t. p. 15K =* IbicU i>. 157. * Ibid. p.. 155. 



