12 ANIMAL INTELLIGENCE 
sented to me when a youth by a very profound and 
much-esteemed school-teacher of mine, who was good 
enough to give me occasionally the benefit of his own 
thinkings, and the more I examine myself, and look 
into the psychic life of others, the more do I feel the 
force and justness of my teacher’s view. 
Are we not in like manner too ready to adopt simple 
—unduly simple—explanations of the actions of the 
animals by which we are surrounded? You will, of 
course, not suppose that I would claim that the motives 
—using that term in the widest sense—which actuate 
them are of equal complexity with those that determine 
the actions of men in many cases; but in all discussions 
on animal intelligence, and the entire psychic life of 
creatures that are, on the whole, lower in the scale than 
ourselves, we must be careful to distinguish difference 
in quality from difference in degree. And in the in- 
vestigation of so important a distinction it seems to me 
of the greatest moment to compare the human being 
at various stages of his development with the lower 
animals in a corresponding way hence, the, to my mind, 
absolute necessity of investigation of the psychic 
development of both the lower animals and of man, A 
dog at different periods of his existence stands, as it 
were, on different psychic planes. He leaves some 
features of his early life behind him for good—not 
many, however, while he adds and adds new develop- 
ments which, in different dogs, vary with their special 
experience, but not enough to obliterate the general 
characteristics of the canine mind. Just the same may 
be said of the human intellect, and there are few more 
suggestive or fruitful studies for those who have an 
interest in such investigation than the comparison of 
the child and the dog at their different epochs of 
development. Of course, the parallelism is clearer 
during the earlier epochs, and the dog runs through the 
