T 6 Heredity. 



'that aboriginal habits are long retained under domestication. 

 Thus with the common ass we see signs of its original desert life 

 in its strong dislike to cross the smallest stream of water, and in its 

 pleasure in rolling in the dust. The same strong dislike to cross a 

 stream is common to the camel, which has been domesticated from , 

 a very ancient period. Young pigs, though so tame, sometimes 

 squat when frightened, and thus try to conceal themselves even in 

 an open and bare place. Young turkeys, and occasionally even 

 young fowls, when the hen gives the danger-cry, run away and 

 try to hide themselves, like young partridges or pheasants, in 

 order that their mother may take flight, of which she has lost the 

 power. The musk-duck, in its native country, often perches and 

 roosts on trees, and our domesticated musk-ducks, though sluggish 

 birds, are fond of perching on the tops of barns, walls, etc. .... 

 We know that the dog, however well and regularly fed, often 

 buries, like the fox, any superfluous food ; we see him turning 

 round and round on a carpet, as if to trample down grass to form 

 a bed. . . . -. In the delight with which lambs and kids crowd 

 together and frisk on the smallest hillock, we see a vestige of their 

 former alpine habits.' l 



ii. 



Instead of dwelling unnecessarily on the heredity of natural and 

 primitive instincts, c it will be more instructive to inquire whether 

 acquired instincts are transmissible. We have already said, when 

 giving, according to F. Cuvier and Flourens, the characteristics 

 generally attributed to instinctive acts, that none of them are abso- 

 lutely true. Thus, instinct is not always invariable. The beaver 

 changes, according to circumstances, the site and form of his house, 

 and from being a builder becomes a miner. The bee can modify 

 her plan of construction, and substitute for hexagonal cells penta- 

 gonal cavities. In the Island of Goree the swallows remain through^ 

 the whole year, because the warmth of the climate enables them to 

 find food at all seasons. In many species the mode of nest- 

 building varies according to the nature of the soil, the locality, and 

 the temperature of the country. Instinct is certainly not as pliant 

 an instrument as intelligence ; it cannot, like intelligence, adapt itself . 



1 Variation, etc., vol. i. p. 180. 



