i5° 



The Study of Animal Life 



some way been stored within the cells of the brain in the 

 form, from the objective point of view, of a certain 

 arrangement of its particles. 



When, after the revival of past impressions, we are able 

 to discriminate between them, we call them sensations. 



Now sensations are referred, in consciousness, not to 



Fig. 31. — Attitude of a hen protecting her brood against a dog. 

 (From Darwin's Expression of Emotions.") 



the brain cells which discriminate between them, but to the 

 cells of the sense organs which received them. 



Further, we refer, by experience, the causes of sen- 

 sations to the outer world. We do this by a mental pro- 

 cess which is called perception. 



Now out of perceptions, and through associations, there 

 arise expectations. The mental process involved in the 

 formation of an expectation is called inference. 



