156 ANIMAL INTELLIGENCE 



the mouth is naturally assisted by the forelimbs. As 

 locomotive power increases, the puppy takes to walk- 

 ing away and returning to the attack, then running, 

 jumping, etc. 



Soon he begins to shake objects, pull at them, 

 tear them. My observations show conclusively that 

 the movements in play appear in the order of the 

 final perfection of the co-ordinated movements of the 

 animal as represented, so far as the nervous system 

 is concerned, in the cerebral cortex by well-defined 

 centres. I am now, and for some time have been, 

 engaged upon experiments which show that the 

 cortical brain centres do not all develop at the same 

 time, but in a certain order, a fact which throws a flood 

 of light on the psychic, as well as the physical, 

 development of animals. 



The pleasure of play is that of movement at first. 

 Later, there is no doubt a psychic complexity of feeling 

 not known to the very young puppy. 



Nevertheless, the observations reported on the 26th 

 and 33rd days would seem to indicate that even at 

 this early age the puppy has some sense of fun or 

 humour. 



SCEATCHING. I have endeavoured to note the earliest 

 attempts at this act, and give some details from time 

 to time, as it illustrates several points. 



I should be disposed to regard scratching as a 

 hereditary reflex perhaps, as is illustrated by the 

 experiment of the 17th day. In other cases, how- 

 ever, the element of will does enter more or less into 

 this act. Even an adult dog will move his leg in the 

 air in harmony with scratching irritation against his 

 side a pure reflex. When, as noted on the 40th 

 day, the puppy turns his neck so as to adapt the 

 movements of the leg, and the position of the parts 

 to be scratched, it is plain that we have here the 



