248 CHANGES OF HABIT OR INSTINCT 



rigorous selections, and have been transmitted for an 

 incomparably shorter period, under less fixed conditions of 



life. 



IIow strongly these domestic instincts, habits, and 

 dispositions 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 

 obstinacy 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 Eoy describes a dog, whose great-grandfather 

 was a wolf, and this dog showed a trace of its wild parent- 

 age 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 is not true. No one would 

 ever have thought of teaching, or probably 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 tendency to this strange habit, 

 and that the long-continued selection of the best individ- 

 uals in successive generations made tumblers what they 

 now are; and near Glasgow there are house- tumblers, as I 

 hear from Mr. Brent, which can not 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: the act of pointing is prob- 

 ably, as many have thought, only the exaggerated pause of 

 an animal preparing to spring on its prey. When the first 

 tendency to point was once displayed, methodical selection 

 and the inherited effects of comj^ulsory training in each 

 successive generation would soon complete the work; and 

 unconscious selection is still in progress, as each man tries 

 to procure, without intending to improve the breed, dogs 



