SPECIES IDENTITY OF NUCLEUS-PLASMA NORM 475 



in morphology, mainly of absolute size, but they are very minor 

 and interfere not one whit with the really significant changes of 

 immediate function. After six years of continuous study of a 

 single type of cell, I know of no changes in that cell which have 

 not their explainable origin in function, save only the obvious 

 ones of faulty technic such as lack of proper dehydration, over- 

 heated paraffin, and the like. When it is properly done, how- 

 ever done, the essential picture is always constant. Nissl's 

 artefact chromophile cell is present when function has not gone 

 beyond that stage; when function has gone further, Nissl's 

 chromophile cell is absent. 



Incidentally, it must be pointed out that conclusions based 

 on cell measurements with the factor of function neglected can- 

 not be exact and are very likely to be incorrect. When one con- 

 siders that the exhausted Purkinje cell is three or four times 

 the volume of the resting cell and the exhausted crayfish cell 

 even ten or fifteen times the volume of its resting cell, the necessity 

 of limiting comparisons of individuals or averages to correspond- 

 ing grades of function is obvious. While this restriction is most 

 pertinent to the nerve cell, it must be true in varying degree for 

 all types of functioning cells. 



THE BIOLOGIC FACTORS OF DEVIATION FROM A CONSTANT 

 NUCLEUS-PLASMA RELATION 



All vital phenomena of cells, as manifestations of transfor- 

 mations of energy, are reducible in terms of three attributes — 

 reproduction, function and nutrition. Growth is not neglected, 

 for, following Hertwig, growth is held to be either divisional or 

 functional. The differentiated nerve cell has lost the power of 

 division. Shifts in the nucleus-plasma relation due to divisional 

 activities are therefore eliminated after the embryonic period. 

 There remain, in a fundamental analysis of cellular phenomena 

 reacting to modify or change the organic structure and relations 

 of the cell, its physico-chemical constitution, just two things, 

 function and food. 



As concerns function in the case of the nerve cell, it must 

 first be set forth with what right and upon what basis so vast 



