REFLEX ACTION 



593 



nated as perception or association reflexes. Thus, the flow of saliva or gastric 

 juice may be eUcited upon gaining a visual or olfactory concept of well-cooked food. 

 Quite similarly, the yawning reflex may be evoked in us in consequence of a visual 

 impression of some one else already engaged in this act ; or we may receive stimuli 

 tending to produce micturition at the sight or sound of running water. To this 

 group also belongs the act of vomiting at the sight of foul food, as well as the so- 

 called idiomotor movements. The latter consist in involuntary movements 

 executed by us in imitation of the position of other people. Thus, we may follow 

 the movements of a football player and find ourselves eventually in a state of 

 muscular contraction without actually realizing how we got into it. 



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