292 PSYCHIATRY 



reveals their importance for an understanding of the genesis or 

 emotional changes, and the alterations of the affective tone in 

 states of persistent mental depression. The sense of well-being and 

 ill-being depends upon these variations. Most important of all, 

 because so completely neglected in psychiatry, are the bluntings 

 and losses of organic sensations and the consequent effects upon 

 the feeling-tone and ideation; in this regard attention should be 

 called, especially, to a remarkable fact well established in physi- 

 ology and psychology. It is evident that the normal irritability 

 of nerve and muscle requires the maintenance of a certain chemical 

 constitution; slight variations from this, temporary or continuous, 

 alter or may destroy the irritability. Further, it is noticeable in most 

 cases that the first step toward deterioration is a rise of irritability ; 

 the cause being increased or continued, sooner or later exhaustion 

 supervenes, the irritability lessens, and is finally lost. 1 These func- 

 tional reductions of sensibility, in a wide range of varied degrees and 

 combinations, are constant symptom-factors in psychiatry. 



The relation of mental physiology having an essential importance 

 for psychiatry there should be a first reference of all mental symptoms 

 to their functional sources in the organism as far as possible with 

 respect to their correlation and association with alterations of bodily 

 functions. By the genetic method study should begin with the 

 minor changes from normal action; these alterations show intensi- 

 fications and losses of function, and symptom-groups are modified 

 by their varied combinations. 



Mental Physiology and the Functional Psychoses 



The true basis of a pathological physiology in psychiatry is mental 

 physiology and its physical correlations of function; variations of 

 nervous and mental' reactions in their initial stages may be wholly 

 functional. Approaching the subject newly from this point of view 

 the physician is assumed to know the modes of reaction of the 

 nervous and mental mechanisms and that part of the work done by 

 the nervous system leads to consciousness; he should know also the 

 primary postulates of psychology. Having to study the operations of 

 other minds, he needs to distinguish, in descriptive terms, his own 

 conscious experiences. 



A helpful method in psychiatry is to separate the experiences that 

 relate to the outer world from those that belong to the inner life. 

 Professor Sanford presents this idea in discussing the relation of 

 psychology and physics, to which reference has been made. He 

 describes the conscious experiences that may be called physical phe- 

 nomena: percepts or series of percepts belonging chiefly to thesense- 

 1 Am. Text-Book of Physiology, vol. n, p. 61. 



