124 Habit and Instinct. 



from their parents they not only had never seen the 

 operation of burying a nut, but were totally unacquainted 

 with the properties both of earth and of nuts." 



In this case the untaught instinctive procedure is all 

 the more marked since it effected no good purpose. So 

 far as it goes, too, it would seem to be pure congenital 

 whisky undiluted by the water of experience. On the 

 other hand, the way in which Dr. Mills taught his kitten 

 habits of cleanliness is an equally instructive object- 

 lesson in acquisition through association, accompanied, 

 however, by some instinctive traits, such as the pawing of 

 the sand. 



I have drawn largely on the observations which Dr. 

 Mills has placed on record in the papers to which reference 

 has been given. Let me assure the reader that much 

 remains of equal interest and importance. The diaries 

 should be carefully read by all students of animal habit 

 and instinct. Especially interesting are the observations 

 on the so-called " play instinct," the outcome of an excess 

 of vital energy finding expression in varied activities, all 

 of them more or less directly correlated with those which 

 are of importance in subsequent life, and giving oppor- 

 tunity for the development of the motor control so essential 

 to that life. Interesting, too, is the marked effect on 

 development of allowing a mongrel puppy, hitherto brought 

 up in comparative seclusion, to mix with other dogs. 

 " His advancement was literally by leaps and bounds." 

 The less social nature of the kitten, so far as members 

 of its own kind were concerned, is also noted. " The 

 behaviour of one kitten," says Dr. Mills, "has less 

 influence on the others than that of one puppy on its 

 fellows." The length of time required by the kitten — 

 much more marked than is the case with the puppy — to 

 learn how to lap milk successfully, and, later, to eat 



