A NOTE ON THE PERSISTENCE OF AN INSTINCT 



K. S. LASHLEY 



Ordinarily the nursing instinct in young mammals is very 

 transitory, being readily suppressed and superseded by the 

 developing habits of obtaining food in other ways, and with 

 its disappearance the co-ordinated group of reflexes involved 

 in sucking seems in many species to be completely lost. In 

 the case of man, however, recent investigations indicate that 

 the persistence of this instinct in some perverted form into 

 adult life is by no means uncommon. This brings to the front 

 the question of the existence of a similar condition in animals. 

 The following observations upon the continuation of the suck- 

 ing reflexes into the adult life of the cat may be of interest in 

 this connection, although little insight into the causes of the 

 behavior has been obtained. 



The first case of this sort, coming to my attention some years 

 ago, was that of an adult male cat (J), two years old, which per- 

 sisted in sucking at the fur and skin of other cats, pets in the 

 same household. The cats were accustomed to lie together in 

 the sun or before the fire, washing each-other's faces and ex- 

 changing other amities. In such friendly overtures J was par- 

 ticularly active, but he always ended his ministrations by first 

 licking the fur of his companion's throat until it was thoroughly 

 wet and then applying his lips to the exposed skin and sucking 

 vigorously. If uninterrupted he would lie thus for hours and 

 if he were pulled away suddenly, a faint oozing of blood was 

 generally visible on his companion's throat where his lips had 

 been applied. Since the behavior was somewhat detrimental 

 to the other cats it was broken up by the application of Cayenne 

 pepper to their throats. 



The second case is more interesting since a little of its history 

 is known. In the summer of 1913 a kitten was taken from her 

 mother before she had learned to drink and for several days was 

 fed by hand, sucking at bits of rag soaked in milk. She was 



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