216 ANIMAL INTELLIGENCE 



attempting to compare the mongrel puppy and the 

 St Bernards. The latter, I consider an unusually active 

 litter, while the mongrel, for a considerable period, 

 seemed to me more than usually vegetative. Moreover, 

 while there were always at least four St Bernards 

 together, this mongrel was the only one of this litter 

 after about the 20th day. 



One of the features of development greatly impressed 

 on my mind by these comparisons, not to mention 

 many other similar ones, was the influence of one on 

 another in all the lines of development. This was 

 shown both negatively and positively in the case of 

 the mongrel. After he began to mingle with the older 

 dogs his progress was marvellous. He seemed in a 

 few days to overtake himself, so to speak, and his 

 advancement was literally by leaps and bounds. It is 

 very difficult to give an adequate idea of this feature 

 of the mongrel's history in a diary, but I wish to 

 note it specially, because it seems to me to show that, 

 while education, in the wider signification of that word, 

 may in a sense account for development, it is equally 

 true that the real nature of any animal will, in the 

 main, assert itself sooner or later, however unfavourable 

 the early environment. In other words, heredity is, 

 was, and ever will be, stronger than environment. 



One may safely say that in all kinds of dogs the 

 perception of light and shadows precedes the seeing 

 of objects, and that the latter is comparatively slowly 

 developed. 



The mongrel seems to have been very slow in develop- 

 ing the play instinct, which I attribute largely to his 

 being the sole puppy from an early period, and therefore 

 seeing no other dog but his dam. 



In both the mongrel and the pure-bred puppies 

 hearing progresses rapidly to perfection of sensation. 

 Within about ten days the maximum of acuteness is 



