Chap. I. SERVICEABLE ASSOCIATED IIABITS. 47 



lieved by some naturalists to be specifically extinct), 

 when comfortably lying on a warm shawl or other soft 

 substance, to pound it quietly and alternately with their 

 fore-feet; their toes being spread out and claws slightly 

 protruded, precisely as when sucking their mother. 

 That it is the same movement is clearly shown by their 

 often at the same time taking a bit of the shawl into 

 their mouths and sucking it; generally closing their 

 eyes and purring from delight. This curious move- 

 ment is commonly excited only in association with the 

 sensation of a warm soft surface; but I have seen an 

 old cat, when pleased by having its back scratched, 

 pounding the air with its feet in the same manner; so 

 that this action has almost become the expression of a 

 pleasurable sensation. 



Having referred to the act of sucking, I may add 

 that this complex movement, as well as the alternate 

 protrusion of the fore-feet, are reflex actions; for they 

 are performed if a finger moistened with milk is placed 

 in the mouth of a puppy, the front part of whose brain 

 has been removed. 17 It has recently been stated in 

 France, that the action of sucking is excited solely 

 through the sense of smell, so that if the olfactory nerves 

 of a puppy are destroyed, it never sucks. In like man- 

 ner the wonderful power which a chicken possesses only 

 a few hours after being hatched, of picking up small 

 particles of food, seems to be started into action through 

 the sense of hearing; for with chickens hatched by arti- 

 ficial heat, a good observer found that " making a noise 

 with the finger-nail against a board, in imitation of 

 the hen-mother, first taught them to peck at their 

 meat." 18 



17 Carpenter, ' Principles of Comparative Physiology,' 

 1854, p. 690, and Miiller's 'Elements of Physiology,' Eng\ 

 translat. vol. ii. p. 936. 



18 Mowbray on ' Poultry,' 6th edit. 1830, p. 54. 



