FUNCTIONAL V. VEGETATIVE ACTIVITIES 293 



is not intrinsic : it does not arise within the cell but comes from 

 without. Vegetative functions, on the other hand, including 

 cell division, would seem to be of intrinsic origin and automatic, 

 determined only indirectly by external conditions, directly by 

 conditions within the cell. The normal cell, in short, stands in 

 very much the same relationship to the organism as does the 

 normal citizen to the body politic : the work that individual 

 performs is determined by his position in the body politic, and 

 is for the benefit of society at large, but at the same time the 

 individual citizen works for himself and for the continuance of 

 his species. The one, it is true, depends upon and is intimately 

 connected at every point with the other function of the individual, 

 but these two functions of citizenship and self-preservation are 

 clearly distinct, the one determined by external conditions, the 

 other being individual and inherent. 



So long as the cell is not called upon to work, and for so long 

 as the surrounding conditions are unaltered, we have the inertia 

 of rest, and for so long there is no call either for increased 

 activity and breaking down of its tissue, or for subsequent build- 

 ing up in excess of vegetative needs. A cell lying functionless 

 and latent does not therefore show any tendency to proliferate. 

 Alter these surrounding conditions and a condition of increased 

 metabolism may be induced. 



Position of the " Cell Rest " Theory 



Thus a " cell rest " * may remain latent for years or for life, 



showing little or no signs of growth. The very fact that it is 



not in a position to perform adequate function is against growth, 



so long as the conditions are unchanged. Change the conditions, 



and this same fact that it is not in a position to perform adequate 



function is evidently the reason why the cells forming that 



" rest " show a peculiar tendency towards proliferation. They 



are stimulated from without by physical and other means ; 



their relationships to other cells, whether merely of tension or of 



tension plus position, become altered, and the reactive increased 



anabolism and storing-up of cell material which cannot be used 



up in active work to the same extent as occurs in normally 



situated cells, is the essential cause why now the stored-up 



1 [The persistent remains of a foetal organ, or group of cells of an organ 

 displaced during the course of development.] 



