xi KNOWLEDGE OF CONCRETE OBJECTS 257 



children. Whether this was due to a generalisation from 

 teasing boys, and the nurses who accompany them, I do 

 not know. The point remains, that Jimmy was guided 

 by a general, or, as it might be called, a class resemblance, 

 and this again not to the detriment of his knowledge of 

 individuals, 1 for I have seen him get into a state of wild 

 excitement on merely hearing the footsteps of his former 

 keeper. 



Little facts of this kind suggest that the assemblage of 

 qualities which constitute an individual make a certain 

 impression upon the animal mind, 2 and prepare it to deal 

 with objects presenting a general similarity to those with 

 which it is familiar. In short, an animal reacts, not only 

 to resemblances of simple sense quality, but to the more 

 general similarities which unite the individuals of a class. 

 Such similarity is notoriously difficult to analyse ; but it 

 seems to be a similarity in which many elements are con- 

 cerned, and in which the relation between the elements is 

 perhaps the determining feature. I one day gave Jack his 

 box with a footstool in front, which prevented the door 

 from opening. After very little hesitation, Jack scratched 

 away the stool and got at the door ; and he repeated this 

 action when for the wooden footstool I substituted a large 

 hassock. Now, Jack would be of course accustomed to 

 scratch at things, and in particular to scratch away earth 

 to find a buried bone. It is extremely unlikely that he 

 ever before had to scratch away a similar object under 

 similar circumstances. It was again an act of common 

 sense, the application by a kind of analogy to a new object 

 of an action familiar under other circumstances. The 

 similarity connecting this action with Jack's ordinary ex- 

 perience would be a similarity in the relation between the 

 thing desired and the obstacle hindering access to it. 

 Similarly, when I gave Jack a box with a new sort of 

 fastening (the catch), he attacked it at once and per- 

 sistently. Though he did not know what was to be 



1 At the same time his memory is very short. He clearly did not 

 recognise me at first after a few days' absence. 



2 On this point see some good remarks in Mr. Schaler's Domesticated 

 Animals, p. 39, on a dog's knowledge of the boundaries of his master's 

 property. 



