THE RECOVERY FROM DEPRESSION 491 



The objective fact is correlated with the quantitative principle 

 that some relative recovery is possible for every grade of depres- 

 sion necrobiosis until nuclear death is absolute. Depression has 

 a comparatively greater potentiality of recovery than has ex- 

 haustion, which is to be referred to the relative advantage main- 

 tained by the nucleus in both acute and chronic states. 



A depression which goes too far in degree or time results in a 

 permanent disorganization of the cell. Progressive diminution 

 of chromidial apparatus, atrophy of plasma and nucleus, pig- 

 mentation, loss of nuclear integrity, and finally, disappearance 

 of cells are indicative of such a change, relative or absolute. Up 

 to cell death, however, the nucleus-plasma relation of depression 

 holds as an index of a continued process, and the capacity of 

 functional metabolism on lowered quantitative levels and of 

 some relative recovery by functional growth persists. 



The essentially permanent state of disorganization consti- 

 tutes an organic senility of depression. This is the quantitative 

 opposite of senility of function, of final organic exhaustion, and 

 the dual nature of the senescent process for the nerve cell in 

 its state of differentiation is thus established. 



Both senility of function and senility of depression conform to 

 the lowered functional metabolism which has been conditioned by 

 other investigators for the senile state. 



There is no rejuvenescence of the nerve cell, for there is no 

 dedifferentiation within the working of the quantitative principle, 

 but only a recovery, which, whether from depression, from disuse 

 atrophy or exhaustion, involves the regrowth of the same pre- 

 existing substances. The reason why the nerve cell remains un- 

 impaired through long years of life is that the specific products 

 of its differentiation are entirely consumed in the functional re- 

 action and the by-products eliminated, while the condition of 

 rapid metabolism, which is the condition of youth, is sufficiently 

 fulfilled, unless the inner exhaustion goes too deeply, or unless 

 external conditions depress it. From its place in the organic 

 system it follows that senility and death of the nerve cell are at 

 some time inevitable. 



