SPECIES IDENTITY OF NUCLEUS-PLASMA NORM 477 



to stimuli differs only in a quantitative way. The possibilities 

 are only activity or depression. The consideration further 

 therefore as to kind of phenomena becomes merely part of the 

 consideration as to degree, the only essential difference is a 

 quantitative one, and in all respects save degree functional 

 phenomena are identical. In other words, to quote a former 

 conclusion ('13 b) it is the constitution of the nerve cell, for which 

 sensitiveness to stimuli is the specialized function, that, if it 

 reacts at all, whatever the stimulus, it reacts in the natural 

 direction either of exaltation or inhibition of the capacity of a 

 mechanism which serves all phases of function. Function is 

 primarily referable to a quantitative reaction, fundamentally 

 the same in every nerve cell. The facts stated in this paper give 

 the final proof — after all the alternation of increase and decrease 

 of substance for any given activity, hyperchromatism and 

 hypochromatism, the cell comes back to a constant nucleus- 

 plasma relation. It means that there is lacking a specificity or 

 inherent peculiarity in the reaction of one nerve cell as compared 

 with another. Inherent differences in specific cellular powers 

 are not at all demanded in explaining the most diverse function. 

 This does not exclude qualitative differences of a sort. A 

 difference in chemical quality of protoplasm, specifically of 

 chromatin, is predicated not only phylogenticallj' but ontogenetic- 

 ally for varying degrees of differentiation ('13 a). The distinc- 

 tion is that as limited within a species this difference in quality 

 is between one individual and another, and within an individual 

 between different types of cells; the quality of the protoplasm 

 within cells of the same type within the same individual is un- 

 doubtedly a close constant. Secondly, as a result of natural 

 causes such as repeated cycles of activity producing age or of 

 injurious agencies such as disease, a qualitative deterioration 

 is predicated by such things as a deficiency of elaboration of 

 chromatii;! and nucleolar substance and a loss and relative slow- 

 ness of the power of recuperation which is anatomically evident. 

 But the distinction here is that the reaction of a given moment 

 is regarded as starting from the fixed quantitative status belong- 

 ing to that moment and that reaction so far as concerns the 



