470 DAVID H. DOLLEY 



the other half by ten days. Either of these three exposu'res 

 would have produced a profound depression in all cells with some 

 degenerative effects according to the results of Butler ('16) from 

 this laboratory. Yet six days of recovery from a reduplication 

 thereof was sufficient for a complete return, in fact if anything a 

 return in excess, in all cells which were not seriously affected 

 organically. More significant, cells which by their atrophy 

 showed the more serious effects of depression exhibited usually 

 a complete renewal of extranuclear chromatic substance. These 

 observations apply universally so far as chromatic recovery is 

 possible. 



Considering the karyosome, after exhaustive activity it is fre- 

 quently the very last organelle to be restored. Some depression 

 is almost invariably associated with karyorrhexis and karyolysis 

 of the karysome. Yet in the above animal, recovery of the 

 karyosome was almost universal, even in the severely affected 

 cells. The total result of the rapid chromatic recovery with the 

 clearing up of the plasma would be to give a fictitious idea of 

 its completeness were relative sizes to be disregarded. 



Recovery of plasma volume is obviously the slowest phase. 

 It is best determinable in those cells in which the depression went 

 to a structural disorganization involving the nucleus. In them, 

 though the chromatic restoration approximates the proper one, 

 both plasma and nucleus are shrunken, frequently irregular, but 

 the plasma is plainly relatively smaller. Measurements, which 

 were applicable to depression itself, functional stage by stage, 

 are out of the question to demonstrate this because of the widely 

 varying degrees of atrophy and other involvement wdthin the 

 stages. But working from the pronounced manifestations, in- 

 stances of a nucleus with a disproportionately small plasma for 

 every stage of function which became severely depressed are 

 plain after chromatic recovery to one experienced in relative 

 cells sizes. It is probable, however, that the inconsiderable 

 shrinkage of a physiological depression in the strictest sense is 

 rapidly recuperated from, although beyond observation. 



These changes of relative and absolute cell atrophy are the 

 first and may be the mildest indication of a permanent structural 



