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 
= “2s 
n —_aan 
Sea SPIE SIRT 
2 RRS Seeger 
