THE RECOVERY FROM DEPRESSION 485 



factor in both natural senility and senility of depression in the 

 nerve cell, as follows. 



In natural senility, the progressive atrophy of plasma and 

 nucleus, with prior disappearance of the nucleus, the progressive 

 deficiency of chromatin elaboration due to nuclear exhaustion, 

 associated with deficiency of nucleolar substance, and the pro- 

 gressive failure of the power of recuperation or regrowth, all 

 predicate the ascendency of katabolism, the decrease of con- 

 structive metabolism. Natural senility is one of organic ex- 

 haustion, and in this respect it fulfills the state of the metab- 

 olism conditioned by these investigators. 



In depressant senility, the decrease or failure of constructive 

 metabolism is the outstanding exhibition of the cellular process. 

 Again there is progressive atrophy from lack of synthetic up- 

 building, in this case primarily a cytoplasmic factor, a progressive 

 deficiency of the chromatin supply, due now not only to lack of 

 primary plasmic building substances, but to failure of reciprocal 

 nucleus-plasma relations, and a loss of recuperative power for 

 the same reasons. SeniHty of depression likewise fulfills the 

 condition of lowered metabolism. 



As to the rate of metabolism which Child emphazises, there 

 seems no reason to doubt that both kinds of senility would involve 

 a decrease in rate. The reciprocal interchange between plasma 

 and nucleus is disturbed or interrupted, in one mainly on the 

 part of the plasma (depression), in the other mainly on the part 

 of the nucleus (exhaustion). 



This relation of senility to metabolism has been purposely 

 written in very general terms. It could be written, perhaps more 

 convincingly but beyond the scope of this paper, in detailed 

 terms of the central theme to which all lines of work have con- 

 verged, — a common metabolic basis for all nervous reactions 

 of a cell type from which there is only a quantitative divergence. 

 Thus both natural senility and senility of depression can be shown 

 to be only quantitatively different, each in its way, in respect to 

 metabolism of the normal cell. For, in some explanation, the nu- 

 cleus-plasma relation has been interpreted to be a reciprocal metab- 

 olic relation between plasma and nucleus. The specific end result 



