THK PSYCHIC DEVELOPMENT OF YOUNG ANIMALS. 53 



undifferentiated character, and the auditory meatus is scareeh' to be recognized. The ear in 

 fact sjrows and difterentiates after birth in somewhat tlie same way as the eyelids, but the 

 latter are invariably in advance, so that there are physical reasons for the deafness of 

 puppies. Even after the ear seems to be opened up, the introduction of a fine probe is 

 impossible as I have shown. 



Psychic manifestations may be looked at from so many différent points of view and the 

 correct interpretation is so often doubtful, especially in the lower animals — one's explana- 

 tions are apt to be so artificial, narrow or otherwise imperfect that I shall under several 

 headings now refer to the early development of the puppy. 



Play. — I have endeavoured to follow ver}' closely the development of the plaj' instinct, 

 so important is it as a means of physical and psychic development as well as an indication and 

 an index of the latter, in fact of both. The reader is referred to records of the 13th, 15th, 

 21st, 27th and 32n(I days more especially. I have felt keenly my inability to record all that 

 I have seen in this connection, not to mention the thoughts suggested, which, lack of space 

 prevents me making even an attempt to indicate. 



What is play? One observes, first of all, that the pn[ipy uses its mouth generally on a 

 fellow, then or simultaneouslj' its paws ; but soon the movements are more complicated, 

 prolonged and accompanied by various vocal expressions which are of a significance which 

 varies with the age of the puppy. 



There is not the slightest attempt at play during the period of eye-closure. 



At first playing seems to arise in part from an excess of motor energy which must be 

 discharged, and as it is in the nature of the dog to use his jaws so much the play takes the 

 special form of biting; then the mouth is naturally assisted by the forelimbs. As locomotive 

 power increases the puppy takes to walking away and returning to the attack, then running, 

 jumping, etc. 



Soon he begins to shake objects, pull at them, tear them. My observations show con- 

 clusively 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 coucerned 

 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 throw^s 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 piippy. 



îsTevertheless the observations reported on the 26th and 33rd days would seem to indi- 

 cate that even at this early age the puppy has some sense of fun or humour. 



Scratching. — 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 L7th day. In other cases, however, the element of will does enter 

 more or less into this act. Even an adult dog will move his leg in the air in harmonj' 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 element of will as well as a fine example 

 of neuro-muscular co-ordination. 



