1 8 Heredity. 



When an animal is capable of education, that is, when its original 

 instincts are capable of modification, it usually requires three or 

 four generations to fix the results of training and to prevent a 

 return to the instincts of the wild state. If we try to hatch the 

 eggs of wild ducks under tame ducks, the ducklings will scarce have 

 left the egg when they obey the instinct of their race, and take their 

 flight. If they be prevented from flying away, and kept for repro- 

 duction, it will be several generations before we have tame ducks. 

 The same may be said of free, or wild herds of horses. Their 

 colts are broken with great difficulty, and even after taming they 

 are far less docile than horses born in a state of domestication. 

 Nay, even the mongrel progeny of wild and domesticated horses, 

 or of wild and domesticated reindeer, take three or four genera- 

 tions before they entirely give up the shy habits of their natural 

 state. On the other hand, colts bred of a well-broken sire and 

 dam oftentimes come into the world with a marked aptitude for 

 training; and some horse-trainers have even proposed to select 

 brood stock exclusively from among horses that have been prac- 

 tised in the circus. 



Originally man had considerable trouble in taming the animals 

 which are now domesticated ; and his work would have been in 

 vain had not heredity come to his aid. It may be said that after 

 man has modified a wild animal to his will, there goes on in its 

 progeny a silent conflict between two heredities, the one tending 

 to fix the acquired modifications, and the other to preserve the 

 primitive instincts. The latter often get the mastery, and only 

 after several generations is training sure of victory. But we 

 may see that in either case heredity always asserts its rights. 



Among the higher animals, which are possessed not only of 

 instinct but also of intelligence, nothing is more common than to 

 see mental dispositions, which have evidently been acquired, so 

 fixed by heredity that they are confounded with instinct, so spon- 

 taneous and so automatic do they become. Young pointers have 

 been known to point the first time they were taken out, sometimes 

 even better than dogs that had been for a long time in training. 

 The habit of saving life is hereditary in breeds that have been 

 brought up to it, as is also the shepherd-dog's habit of moving 

 around the flock and guarding it. 



