Heredity of Instincts. 19 



Knight has shown, experimentally, the truth of the proverb " a 

 good hound is bred so." He took every care that when the pups 

 were first taken into the field they should receive no guidance from 

 older dogs. Yet the very first day one of the pups stood trem- 

 bling with anxiety, having his eyes fixed and all his muscles strained 

 at the partridges which their parents had been trained to point. A 

 spaniel, belonging to a breed that had been trained to woodcock- 

 shooting, knew perfectly well from the first how to act like an old 

 dog, avoiding places where the soil was frozen, and where it was 

 therefore useless to seek the game, as in such places there is 

 no scent Finally, a young polecat-terrier was thrown into a state 

 of great excitement the first time he ever saw one of these animals,- 

 while a spaniel remained perfectly calm. 



In South America, according to Roulin, dogs belonging to a 

 breed that has long been trained to the dangerous chase of the 

 peccary, when taken for the first time into the woods, know the 

 tactics to adopt quite as well as the old dogs, and that without any 

 instruction. Dogs of other races, and unacquainted with the 

 tactics, are killed at once, no matter how strong they may be. 

 The American greyhound, instead of leaping at the throat of the 

 stag, attacks him by the belly and throws him over, as his an- 

 cestors had been trained to do in hunting down the Indians. 



Thus, then, heredity transmits acquired modification no less than 

 natural instincts. There is, however, an important difference to be 

 noted : the heredity of instincts admits of no exceptions, while in 

 that of modifications there are many. It is only when variations 

 have been firmly rooted ; when, having become organic, they con- 

 stitute a second nature, which supplants the first ; when, like 

 instinct, they have assumed a mechanical character, that they can 

 be transmitted. If we note these differences in passing, we shall 

 find them lead us hereafter to important conclusions. 



in. 



WE have just shown, from indisputable facts, that heredity governs 

 the transmission of instincts, whether acquired or primitive. It 

 might seem that in this portion of our inquiry, which has to deal 

 only with the facts, we ought to be content with that exposition of 

 the case. But certain theories, put forth by distinguished writers 



