RELATIONS OF ABNORMAL PSYCHOLOGY 753 



If we put this interpretation upon the essential fact of depression, 

 the feelings of imperfection are only the expression in the mind of 

 the subject, of a real lowering of the mental level. The apparent 

 agitation seems to me to be a sort of derivative; the psychical 

 tension, since it is not employed upon the higher mental phenomena 

 which it is no longer capable of producing, is expended upon lower 

 phenomena; and it may now give rise to a veritable explosion of 

 phenomena which are infinitely numerous and powerful, but which 

 always occupy an inferior place in the hierarchy. 1 These feelings 

 and this derivation will disappear when the higher phenomena 

 have again become possible in the opposite state of excitation. 



This rapid sketch shows us what has been the direction taken 

 by the chief investigations of pathological psychology. We have 

 summarized the results of numerous investigations which have 

 already been made, and have indicated the trend of those that are 

 to come. What problems are set for us to solve by the notion of an 

 oscillation of the mental level? What phenomena are characteristic 

 of the depression and of the reelevation (excitation) of the level? 

 In other words, what precise position in the hierarchy is occupied 

 by each mental function? A rapid association of ideas, and a de- 

 velopment of automatism do not always indicate an elevation. 

 There are agitations which coincide with depressions, and which 

 may be regarded as a sort of derivative. How does the derivation 

 come about? How do the phenomena belonging to a lower level 

 replace a vanished phenomenon of a higher level? What are the 

 characteristics of excitation, which has been studied much less 

 than depression? What factors determine these two groups of 

 phenomena? How does it come that in different diseases these 

 phenomena appear now in one form, now in the alternate form? 

 What is the mental result of the indefinite prolongation of a state 

 of depression or of excitation? The answers to these questions will 

 doubtless some day help us to solve the difficult problem of the 

 classification of mental diseases. Finally, is it possible to discover 

 therapeutic agents, whether physical or mental, which will act 

 upon the oscillations? Our knowledge upon all of these points is 

 still in a rudimentary stage. But it seems safe to assert that the 

 notion of the elevation of mental levels is beginning to assume a 

 definite form; and that it has opened up to us an important chapter 

 of pathological and of normal psychology. 



1 Obsessions et psychasth&nie, i, p. 994. 



