SPECIES IDENTITY OF NUCLEUS-PLASMA NORM 497 



from two animals used in the aggregate computations, one an 

 undisturbed normal, the other after a condition of surgical 

 shock. Eleven cells, seven at two micra and four at one micron, 

 belonged to the shocked animal, and four cells, three at two micra 

 and one at one micron belonged to the normal. The prismoid 

 formulas were applied to all one micron cells and to three two 

 micra cells. 



As tested by all these methods, the nucleus-plasma coefficient 

 holds to a close numerical constancy for all members of the dog 

 species investigated. The actual dispersions of the ratios of 

 nucleus to plasma amid the individual differences of the animals 

 and particularly as set against their wide variations in size are 

 relatively small and appear to be negligible because they permit 

 of explanation on inherently technical factors alone. After 

 three methods, the results fall in the close neighborhood of a 

 common figure, namely, about eleven: the differences between 

 the arithmetic means belonging to each of the methods are such 

 as were predicted by mathematicians befoi'ehand from the nature 

 of the data; and dispersions from the mean become reduced to 

 the minimum in the more mechanical and hence more reliable 

 results after one-micron serials. For the one-micron cells, the 

 arithmetic mean is 11.129, the standard deviation ± .2037, the 

 coefficient of variation .01830, and the extreme dispersions from 

 the mean +.272 and -.325. 



CONCLUSIONS 



1. The law is thus formulated: Resting undepressed nerve 

 cells of corresponding type of all individuals of a species have a 

 mass relation of nucleus to plasma which is a close numerical 

 constant, whatever the age between full development of the 

 relation and senescence, whatever the size of the animal, irrespec- 

 tive of variations in the dimensions and absolute size of the cells 

 both in the same animals and in different animals, and irrespective 

 of the degree of function in excited cells of the same type in the 

 same animal. 



The nucleus-plasma relation theory of Richard Hertwig is a 

 law for the nerve cell. 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 24, NO. 5 



