160 ANIMAL INTELLIGENCE 
organism, somatic and psychic, is dependent on im- 
pressions, ancestral, pre-natal, and post-natal. It is 
simply impossible that it should be otherwise. How- 
ever, in the more restricted sense of the word “ memory,” 
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 experi- 
ments, the fact that they attempted 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 witnessed evidence for my conclusion, which 
in this, and other cases, it is not possible for me to fully 
communicate by words 
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