ANIMAL INTELLIGENCE, AND HOW TO STUDY IT 7 
single case, A collie of mine is very shy, so much so that 
an observer recently remarked that he seemed to act as if 
he were afraid of being beaten. Asa matter of fact that 
dog has always been treated with the greatest consider- 
ation in view of his infirmity. He has improved con- 
siderably, and the causes of this improvement in his 
case I well understand. For the primary cause of the 
shyness in this case one must make a study of his 
ancestors. 
Not only is it necessary in order to understand the 
individual dog to begin with him at his birth and to 
follow his history throughout, but such a course is 
essential for the comprehension of the nature of dogs in 
general, and, personally, I am deeply convinced of the 
importance of such investigations, after having been 
engaged in them for some years. 
When such studies are carried out on representatives 
of different groups of animals, and on different breeds 
or individuals, one’s conceptions of the true nature of 
animal intelligence—or, to use a more comprehensive 
term, the psychic life of animals—is vastly widened and 
altogether more correct in every respect. 
In studying together, for example, a litter of puppies 
and a litter of kittens, the lines of development are 
found to be almost parallel for a time, then to diverge 
more and more. The same applies to the individuals 
of the litter, even though the circumstances under 
which they are reared are the same. 
By this method of comparative study, questions as to 
what is common to the race and to different races 
closely allied, the relative strength of the individuality 
of members of the same litter or family, the influence 
of the surroundings, including in this all that we mean 
by education, and a whole host of other problems arise, 
and are to some extent solved. By varying the con- 
ditions under which the different members of a litter 
