490 DAVID H. DOLLEY 



waste products have impeded, as well as the restoration of ma- 

 terials lost by usury. While Child ('15, p. 297) argues for the 

 possibility of some rejuvenescence of the nervous system, basing 

 it on the subjective effects of vacation or change of activity, the 

 benefits of these are the benefits of rest and recovery of the whole 

 or of one part at the expense of other parts. In respect to plac- 

 ing the nerve cell, the real support of his conception of senescence 

 and rejuvenescence, with which I interpret myself in complete 

 agreement, appears to rest upon the preceding fundamental prop- 

 erties of the nerve cell's differentiation. 



Finally, speculations on a potential immortality from the actu- 

 alities of dedifferentiation and rejuvenescence are naturally con- 

 sequent for undifferentiated cells and cells of a certain order of 

 differentiation, and interesting in not only an abstract but a 

 concrete scientific sense. But when the implication is attached, 

 as it has been of late years in nonscientific writings, of a poten- 

 tial immortality for the highly organized soma, it becomes an 

 absurdity. For any organism possessing a true nervous sys- 

 tem, it would be a brainless immortality. Natural senescence 

 and natural death are , inescapable for this one order — as well 

 as other orders — of differentiated cells. For, though the condi- 

 tions above which lower its metabolism may be escaped for a 

 much more prolonged period than the traditional span of three 

 score and ten for the human organism, they are eventually in- 

 evitable in such an organism. There is no use to speculate on 

 its absolute potential viability by itself, for it has no isolated 

 existence. "Senescence is a retardation resulting from con- 

 tinued dynamic activity under certain conditions in a system" 

 (Child, '15, p. 465). 



CONCLUSIONS 



The process of recovery from organic depression reduces its 

 quantitative upset of the nucleus-plasma relation in favor of the 

 nucleus in essentially the opposite way to recovery from ex- 

 haustive functional activity, which is a quantitative upset in 

 favor of the plasma. The quantitative principle of the func- 

 tional reaction is thus maintained, and all phases of function are 

 now demonstrated to rest upon a quantitative divergence only. 



