Chap. XXII. CAUSES OF VARIABILITY. 251 



like plants, do not depart from their primitive type until 

 they have been subjected during several generations to 

 domestication. On the other hand, Mr. Yarrell informed me 

 that the Australian dingos, bred in the Zoological Gardens, 

 almost invariably produced in the first generation puppies 

 marked with white and other colours ; but these introduced 

 dingos had probably been procured from the natives, who 

 keep iheni in a semi-domesticated state. It is certainly a 

 remarkable fact that changed conditions should at first pro- 

 duce, as far as we can see, absolutely no effect; but that 

 they should subsequently cause the character of the species 

 to change. In the chapter on pangenesis I shall attempt to 

 throw a little light on this fact. 



Eeturning now to the causes which are supposed to induce 

 variability. Some authors 31 believe that close interbreeding 

 gives this tendency, and leads to the production of monstro- 

 sities. In the seventeenth chapter some few facts were 

 advanced, showing that monstrosities are, as it appears, 

 occasionally thus induced ; and there can be no doubt that 

 close interbreeding causes lessened fertility and a weakened 

 constitution ; hence it may lead to variability : but I have 

 not sufficient evidence on this head. On the other hand, 

 close interbreeding, if not carried to an injurious extreme, 

 far from causing variability, tends to fix the character of each 

 breed. 



It was formerly a common belief, still held by some persons, 

 that the imagination of the mother affects the child in the 

 womb. 32 This view is evidently not applicable to the lower 

 animals, which lay unimpregnated eggs, or to plants. Dr. 

 William Hunter, in the last century, told my father that 

 during many years every woman in a large London Lying-in 

 Hospital was asked before her confinement whether any thing- 

 had specially affected her mind, and the answer was written 

 down ; and it so happened that in no one instance could a 

 coincidence be detected between the woman's answer and any 



31 Devay, ' 'Manages Consanguins,' 32 Mliller has conclusively argued 



pp. 97, 125. In conversation I h;ive against this belief, ' Elements o/ 



found two or three naturalists of the Phys.,' Eng. translat., vol. ii. 1842, 



s;»iDt- opinion. p. 1405. 



