THE PROCESSES OF DEPRESSION 237 



expect an abundance of material for the closer analysis of the 

 processes of depression. For the present, however, we must 

 restrict ourselves to the consideration of some individual cases 

 which have been studied somewhat more in detail by physiolo- 

 gists. 



Simple reflection shows the possibility that depression, that is, 

 the retardation of the normal vital processes, can be brought 

 about in various ways. As on the one hand the normal metab- 

 olism of rest is composed of very numerous chemical constituent 

 processes, and on the other hand the closest interdependence 

 exists between these individual constituent processes, it follows 

 that every factor which increases or retards even one of these 

 must secondarily influence the course of the entire activity. 

 Hence a wide range of possibilities exists for the processes of 

 depression. As the complicated works of a clock can, by the 

 stopping of a single moving part, be brought to a standstill, so in 

 like manner the metabolic activity can be depressed by very 

 different constituent members. In spite of this we have every 

 reason to assume that the greater number of all processes of 

 depression result from the primary effect of one or a few con- 

 stituent members. A primary simultaneous depression of all or 

 at least of numerous constituent processes of the entire metab- 

 olism may only be assumed as possible, resulting from decrease 

 of temperature within certain limits. But even in the case of 

 "cold depression" it is not probable, owing to the great effect of 

 every alteration in the relations of masses in the cell, that depres- 

 sion is solely the manifestation of a uniform retardation of all 

 individual constituent metabolic processes. If, therefore, the 

 greater part of the processes of depression are brought about by 

 the primary effects of an individual constituent process, then the 

 possibility must be admitted that any component of the chain can 

 by the means of some specific external influence form the starting 

 point for a depression. The number of the various kinds of 

 processes of depression would be, therefore, enormous. The 

 knowledge obtained up to the present shows, however, that this 

 variety is not quite as great as the above facts might lead one to 

 expect. Even though future investigation will certainly not do 



