MOVEMENT OF ANIMALS, viii. 



been said, is the object of pursuit or avoidance in the 

 sphere of action, and heat and cold necessarily follow 

 the thought and imagination of these objects. For 

 what is painful is avoided, and what is pleasant is 

 pursued. We do not, it is true, notice the effect of 

 this in the minute parts of the body ; but practically 

 anything painful or pleasant is accompanied by some 

 degree of chilling or heating. This is clear from the 

 effects produced. Reckless daring, terrors, sexual 

 emotions and the other bodily affections, both pain- 

 ful and pleasant, are accompanied by heating or 

 chilling, either local or throughout the body. Re- 

 collections too and anticipations, employing, as it 

 were, the images of such feelings, are to a greater or 

 less degree the cause of the same effects. So it is 

 w^th good reason that the inner portions of the body 

 and those which are situated near the origins of the 

 motion of the organic parts are created as they are, 

 changing as they do from solid to liquid and from 

 liquid to solid and from soft to hard and vice versa. 

 Since, then, these processes occur in this way, and since, 

 moreover, the passive and the active principles have 

 the nature which we have frequently ascribed to them, 

 whenever it so happens that the one is active and the 

 other passive and neither fails to fulfil its definition, 

 immediately the one acts and the other is acted upon. 

 So a man thinks he ought to go, and goes, practically 

 at the same time, unless something else hinders him. 

 For the affections fittingly prepare the organic parts, 

 the desire prepares the affections, and the imagina- 

 tion prepares the desire, while the imagination is due 

 to thought or sensation. The process is simultaneous 

 and quick, because the active and the passive are by 

 nature closely interrelated. 



467 



