214 INSTINCT. Chap. VII. 



positions are inherited, and how curiously they become 

 mingled, is well shown when different breeds of dogs are 

 crossed. Thus it is known that a cross with a bull-dog 

 has affected for many generations the courage and obsti- 

 nacy of greyhounds ; and a cross with a greyhound has 

 given to a whole family of shepherd-dogs a tendency to 

 hunt hares. These domestic instincts, when thus tested 

 by crossing, resemble natural instincts, which in a like 

 manner become curiously blended together, and for a 

 long period exhibit traces of the instincts of either 

 parent: for example, Le Koy describes a dog, whose 

 great-grandfather was a wolf, and this dog showed a 

 trace of its wild parentage only in one way, by not 

 coming in a straight line to his master when called. 



Domestic instincts are sometimes spoken of as actions 

 which have become inherited solely from long-continued 

 and compulsory habit, but this, I think, is not true. 

 No one would ever have thought of teaching, or pro- 

 bably could have taught, the tumbler-pigeon to tumble, — 

 an action which, as I have witnessed, is performed by 

 young birds, that have never seen a pigeon tumble. 

 We may believe that some one pigeon showed a slight ten- 

 dency to this strange habit, and that the long-continued 

 selection of the best individuals in successive generations 

 made tumblers what they now are ; and near Glasgow 

 there are house-tumblers, as I hear from Mr. Brent, 

 which cannot fly eighteen inches high without going 

 head over heels. It may be doubted whether any one 

 would have thought of training a dog to point, had not 

 some one dog naturally shown a tendency in this line ; 

 and this is known occasionally to happen, as I once 

 saw in a pure terrier. When the first tendency was 

 once displayed, methodical selection and the inherited 

 effects of compulsory training in each successive gene- 

 ration would soon complete the work ; and unconscious 



