220 THE POPULAR SCIENCE MONTHLY. 



confined on the other side of the partition. At the end of three months, 

 however, the requisite association was established, and the pike, having 

 learned that its efforts were of no use, ceased to continue them. The 

 sheet of glass was then removed ; but the now firmly-established asso- 

 ciation of ideas never seems to have become disestablished, for the pike 

 never afterward attacked the minnows, though it fed voraciously on all 

 other kinds of fish. From which we see that a pike is very slow in 

 forming his ideas, and no less slow in again unforming them — thus re- 

 sembling many respectable members of a higher community, who spend 

 one half of their lives in assimilating the obsolete ideas of their fore- 

 fathers, and through the other half of their lives stick to these ideas as 

 to the only possible truths ; they can never learn when the hand of Sci- 

 ence has removed a glass partition. 



As regards the association of ideas by the higher vertebrated ani- 

 mals, it is only necessary to say that in all these animals, as in our- 

 selves, this principle of association is the fundamental principle of their 

 psychology ; that in the more intelligent animals, associations are 

 quickly formed, and when once formed are very persistent ; and, in 

 general, that, so far as animal ideation goes, the laws to which it is 

 subject are identical with those under which our own ideation is per- 

 formed. 



Let us, then, next ask, " How far does animal ideation go ? " The 

 answer is most simple, although it is usually given in most erroneous 

 form. It is usually said that animals do not possess the faculty of ab- 

 straction, and therefore that the distinction between animal intelligence 

 and human intelligence consists in this — that animals are not able to 

 form abstract ideas. But this statement is most erroneous. You will 

 remember the distinction which I previously laid down between ab- 

 stract ideas that may be developed by simple feelings, such as hunger, 

 and abstract ideas that can only be developed by the aid of language. 

 Well, remembering this distinction, we shall find that the only differ- 

 ence between animal intelligence and human intelligence consists in 

 this— that animal intelligence is unable to elaborate that class of ab- 

 stract ideas the formation of which depends on the faculty of speech. 

 In other words, animals are quite as able to form abstract ideas as we 

 are, if under abstract ideas we include general ideas of qualities which 

 are so far simple as not to require to be fixed in our thoughts by names. 

 For instance, if I see a fox prowling about a farm-yard, I cannot doubt 

 that he has been led by hunger to visit a place where he has a general 

 idea that a number of good things are to be fallen in with, just as I 

 myself am led by a similar impulse to visit a restaurant. And, to take 

 only one other instance, there can be no question that animals have a 

 generalized conception of cause and effect. For example, I had a set- 

 ter dog which was greatly afraid of thunder. One day a number of 

 apples were being shot upon the wooden floor of an apple-room, and as 

 each bag of apples was shot it produced through the rest of the house 



