THE LIVING WORLD 229 



full of milk will give rise to an expectant feeling* 

 which is often subsequently gratified ; but this does not 

 imply that the cat mutely says to itself, " Sounds of cup 

 jingling are probable preliminaries to milk tasting. The 

 sounds I hear are cup jinglings, therefore the sounds I 

 hear are probable preliminaries to milk tasting." 



Finally, the cat has a certain vocal language and a 

 language of gesture. That is to say, it emits different 

 sounds according to the feelings it experiences, mewing, 

 purring and spitting as the case may be. The gesture 

 language of a cat to a beloved mistress is often very 

 expressive of attachment, while the gestures it will 

 exhibit to a threatening dog are unmistakable indeed. 

 The cat by the sounds it emits, or the gestures it makes, 

 has the power of so giving rise to corresponding feelings 

 in other creatures that the latter can often practically 

 understand what it means, as the cat can understand, to 

 the same extent, the meaning of the sounds and gestures 

 of a threatening dog. Such language may therefore be 

 called a language of feeling or "emotion." 



The cat has also the power of acquiring certain habits. 

 Now a habit is a curious and interesting thing. A 

 " habit " is not formed by repeating actions, "though it 

 may be strengthened by them. If an act performed 

 only once had not in it some power of generating a 

 "habit," a thousand repetitions would not generate it. 

 Most animals (certainly such an animal as the cat) have 

 a natural tendency to activity a positive want of it. 

 An animal's powers also tend to increase with activity 

 (within limits) and dimmish with too prolonged repose. 

 Habit is then the determination in one direction of a 

 previously vague tendency to activity. 



* See ante, p. 227, 



