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bear the brunt of the duty while others support them 

 inconspicuously. Certain ones act in advance of others, 

 for coordination is a matter of sequence as well as of 

 combination. The facts observed can be explained 

 upon the basis of "graded synaptic resistance." When 

 a stream of afferent nerve-impulses enters the central 

 gray matter many possible ways lie open to their further 

 flow. But some of these paths are relatively easy and 

 others difficult. The impulses which find a free pas- 

 sage dictate the more powerful muscular responses; 

 those which encounter a greater hindrance find a more 

 limited expression on the efferent side. 



It has been shown that the convulsions of strychnin 

 poisoning, already referred to, are the result of a re- 

 duction of resistance in the central stations such that 

 the paths which are ordinarily impossible to penetrate 

 are freely opened while those that have normally a 

 high resistance come to have no more than the beaten 

 tracks. We should anticipate just such a result as that 

 which we actually see, opposing muscles straining use- 

 lessly, one against another. 



Resistance and Habit. : A reflex act is one which is 

 determined by circumstances and by the organization 

 of the nervous system. The same can be said of a habit. 

 A strong light keeps the pupil contracted and a dish 

 of candy at the elbow causes one to keep taking pieces 

 from it. The principle is similar. But we can usually 

 distinguish without confusion between a reflex and a 

 habit. We keep the first term for those reactions which 

 are inborn or acquired very early in life by all normal 

 individuals. Habits are established later and are more 

 variable. They are personal while reflexes are racial. 

 It is plain, however, that the fundamental condition 

 for a habit is a path of low resistance which favors a 

 certain action when definite stimuli are operative. 



The reflex principle is recognizable in nearly all our 

 behavior. We do not like to have it so for it seems to 

 make us creatures of circumstance rather than masters 



