494 DAVID H. DOLLEY 



variations in the collective cellular reaction after the same dur- 

 ation of overstrain, the just as marked variations in the power of 

 recuperation (Dolley '11 a) in which process it may take one 

 animal two weeks to recover to a degree that another reaches 

 in four days, the variations in the viability of nervous tissue as 

 studied in resuscitations after relative death (Crile and Dolley 

 '08) all of these variations, resulting in young animals, depend 

 primarily upon the individual's quality of protoplasm. The 

 mechanism is identical, the substances through which the mecha- 

 nism accomplishes its work are identical in fundamental con- 

 stitution, and so there remains only the probability of finer 

 differences in chemical composition ('13 a). Explosiveness is 

 an attribute of gunpowder, but even in ordinary gunpowder 

 there are grades of explosiveness. 



With regard to the factor of absolute size of cells, differences 

 therein may be considered according to the more usual distinc- 

 tion at the present time as acquired or innate. As regards ac- 

 quired differences, functional usage leads to increased capacity, and 

 correlative therewith is the functional hypertrophy of the cell. 

 Though its limits vary greatly, increased size of this sort means 

 increased efficiency for the same cell, and hence, presumably, for 

 a constant quality. This principle is well established. Rep- 

 resentatives of the flat type of resting cell vary in their absolute 

 size both in the same and in different individuals as a result of 

 their varying functional hypertrophy. On this account there 

 must be slight variations in intensity of corresponding reactions 

 in even the same individual as well as greater differences between 

 different individuals. This gives acquired absolute size a logical 

 place as a potential factor of variation. 



In the case of innate absolute size, it may be said that the 

 predominant phase of the growth of the nerve cell is functional 

 growth, as stated in an earlier section, and that this fundamen- 

 tally determines absolute size. On this basis, innate growth to 

 an absolute size and a functional hypertrophy, as usually dis- 

 tinguished, have much in common, if, indeed, they do not result 

 from an identical process. Therefore innate absolute size must 

 share a place as a potential factor of variation between indi- 



