THE PSYCHIC DEVELOPMENT OF YOUNG ANIMALS. S5 



as an expression of surplus of energy, liarking in wantonness, etc., all of which is, like the 

 wagging of the tail, highly characteristic of different psychic states. 



All these modes of expressions are to be witnessed with precisely the same interpreta- 

 tion in older dogs at times, though of course, generally the meaning of their barking and 

 growling is more definite. But the puppy persists latent in the dog just as does the boy in 

 the man. 



Dreaming. — Mature dogs do undoubtedly dream, and if one may judge by similar use 

 of the voice and like general behaviour, puppies do also. Leaving out of the question the 

 doubtftil evidence of growling in sleep, the phenomena reported on the 35th day seem to 

 point to dreaming, for the behaviour of the puppy is very similar to that of the mature dog. 



Anger. — Much of the play of dogs is mimic fighting even from the first, and I have 

 noted on the 27th day during play a very brief but decided exhibition of anger such as may 

 occasionally be seen among mature dogs or boys even of eight or nine 3"ears of age during 

 rough pla}'. For the moment anger rules, and the extent to which this is the case and 

 especially the length of time over which it lasts, depends greatly on the breed of dogs. 

 With terriers very early play at times becomes serious and later it may so often become 

 fighting that these dogs cannot always with safety be left together. In few resjîccts do the 

 different breeds show their characteristics or at so early an age as in this. For a very early 

 case of anger (or was it a mere reflex ?) see the i-ecord of the 17th day, and for a clear case 

 the record of the terriers on the 30th day. 



Memory. — In a sense all impressions are remembered, i. e., the state of the nervous 

 system, indeed the whole organism somatic and psychic is dependent on impressions, 

 ancestral, pre-natal and post-natal. It is simplj' impossible that it should be otherwise. 

 However, in the more restricted sense of the word " memor^^ " a good instance is to be 

 noted in the behaviour of the puppy that was accidentally trodden upon by me. This 

 occurred on the 47th day and up to the date of the conclusion of the diary on the 60th day 

 it was very clear that he remembered this unpleasant event. 



Memory is very retentive in dogs though there seem to be in this respect as much 

 individual difference as in human beings. I had a greyhound that could not see a cat on 

 the street without giving chase ; and he would after many months remember the identical 

 tree up which the cat climbed when he was in pursuit. This is moreover a case of visual 

 memory in all probability as it is not likely that the scent from the cat would remain for 

 six months. 



Recognition. — From several experiments recorded, as the result of introducing other 

 bitches into the same compartment with the puppies, the reader may be able to draw some 

 conclusions. From the behaviour of the puppies I conclude that at the time of the later 

 experiments the fact that they attempited to suck the strangers is not evidence that they 

 were mistaken for the dam, but that they simply had such a desire to suck that they were 

 willing to accept what they could get. They in one instance gave the clearest preference for 

 the dam and at once — guided probably by sight chiefly. For dogs' judgments are quickest 

 by sight though often corroborated by smell. Smell is their surest guide and always called 

 into use in doubtful cases. See especially the record for the 36th day. Of course, I wit- 

 nessed evidence for my conclusion, which in this and other cases it is not possible for me to 

 fully communicate by words. 



I have noticed in these and other puppies a quick recognition of human association 



