1 82 Instinct. 



be desirable. That is to him a hint. That ani- 

 mal is preserved ; and the chances are that some 

 of its young will manifest the same characteristics, 

 perhaps in an increased degree. The selection 

 goes on in this direction for generations, — every 

 thing in other directions being rejected and every 

 thing in that direction being preserved, — until the 

 peculiar characteristic is fixed ; sure to appear in 

 every one of the variety or breed. This may ex- 

 plain the difference between Shepherd-dogs, Point- 

 ers, Bull-dogs and other breeds. It is not certain 

 however, that all our dogs came from the same 

 original stock. 



It is to be noticed that this variation in Instinct, 

 is according to a definite plan. Change of Instinct 

 in strength or quality, seems to be accompanied 

 with a corresponding change of structure. The two 

 move on together, by some inscrutable law. The 

 savage temper of the Bull-dog is accompanied with 

 a ponderous jaw and enormou<s strength of muscle. 

 The keen scent of the Blood-hound and the struc- 

 ture for running all harmonize with his instinct for 

 following the prey. The Spaniel and Newfound- 

 land dog readily take to the water ; and their web- 

 feet fit them for this element. 



The Instinct, which leads the fowl to sit upon 

 her eggs, is always connected with a peculiar phys- 

 iological change in the body. That change seems 

 first to awaken the instinct and bring it into play. 

 There is an unnatural heat of the body, — a change 

 in the temper of the fowl, and a disregard of dan- 

 ger In fact, the whole nature of the animal seems 



