290 PSYCHIATRY 



as the immediate effects of use. Some of the common physiological 

 laws have a special importance here because they govern the work of 

 the physical mechanism and therefore of all correlated mental 

 reactions, not only in health but in disease, as long as any functional 

 activity continues. 



(1) Association and Habit are fundamental in mental life; in 

 respect to the association of ideas it is not the ideas that associate 

 but the elementary processes of which the ideas are composed; on 

 the physical side the law reduces to the law of habit (Titchener). 

 Memory is an associative process; mental reactions (including per- 

 ceptions, ideas, emotions) are associated with their physical corre- 

 latives and motor consequences. Habit is closely related; it is the 

 functional disposition to repeat organic processes. This law of asso- 

 ciation and habit applies to "organic memory;" thus "associative 

 memory" is fundamental in, and unites, both psychical and physical 

 reactions. 



(2) Inhibition. The animal organism has a motor character. 

 All sensations and mental states are motor; the entire neuro-muscu- 

 lar organism, mental and motor, acts primarily as a whole, governed 

 by the laws of association, and this is subject to control. "The phe- 

 nomena of nervous life are the outcome of a contest between what we 

 may call inhibitory, and exciting or augmenting forces" (Foster). 

 It is conceivable that all nerve-centres are normally at all times sub- 

 ject to continuous control or inhibition, and are maintained in a 

 condition of mobile equilibrium by the opposition of this inhibition 

 to their own inherent tendency to discharge (Mercier). "Inhibition 

 is an action which obstructs or impedes another action, and which 

 weakens or arrests it if it was already in action " (Oddi). "Voluntary 

 action is at all times the resultant of the compounding of our impul- 

 sions with our inhibitions" (James). "The inhibition of a mental 

 process is always the result of the setting-in of some other mental 

 process" (McDougall). It may be said as a physiological conception 

 that in living substance there are conditions of cohesion and inertia 

 by virtue of the anabolic tendency of its physical and chemical ele- 

 ments; this may be called physiological inhibition, and it is the pri- 

 mary factor in the mobile equilibrium conservatively holding the 

 balance against the tendency to discharge induced by constant 

 external stimulation. The psychological conception of the essential 

 physical fact is that one neural process inhibits another; it may be 

 said that as a will-impulse implies a neural process w.hich may 

 inhibit, or excite and augment, some other mental or neural process, 

 this may be called voluntary inhibition. The great importance of the 

 study of inhibition, which is only indicated here, lies in its holding 

 an equal and counterbalancing place in mental and physical pro- 

 cesse^. 



