496 DAVID H. DOLLEY 



ther, the development of function in the embryo proceeds in a 

 graded fashion to accord with a constant relation of full develop- 

 ment, and finally, the identity of the mechanism in all nerve cells 

 gives the universal apphcation. 



The resting type of nerve cell stands apart as the point of 

 departure for function but uninvolved in the immediate effects 

 of function. From its nature, the resting cell affords an exact 

 basis of comparison between different individuals because it 

 may be identified as unaffected by any factors which might 

 complicate the nucleus-plasma relation. Coincidently with the 

 collateral evidence, several concrete examples of a species con- 

 stancy were found in the resting Purkinje cell type of the rabbit, 

 dog, and man. As a part of the determination of the relation 

 of the resting cell to the functioning cell in the crayfish, a species 

 constancy likewise eventuated, broadened in this case to include 

 all primal types of resting nerve cells on the same level. Upon 

 the basis of these data, verification to warrant the formulation 

 of a law was sought, as follows: 



For the aggregate, calculations were made from the average 

 of measurements of resting Purkinje cells, twenty-five cells to 

 the series, from thirteen individuals of the dog species, which, 

 with those previously made, brings the number of animals to 

 fifteen. The material includes a most heterogeneous assortment 

 of animals of widely varying weights, of all ages, of both sexes, 

 of mixed and fairly pure breed, of different grades of nutrition, 

 and, finally and niost important, of a wide range of both natural 

 and experimental functional states. The single condition of 

 ineligibility imposed was the existence of frank functional de- 

 pression which may affect the resting cell as such. 



For the individual cell, calculations were made from the data 

 from serial sections at two micra and at one micron in two ways. 

 First, wax models were reconstructed and the relative weight 

 of the wax plasma to the wax nucleus was obtained on the theory 

 that the quantitative relations of their prototypes would be 

 preserved. Second, application was made mathematically of 

 the prismoid formulas. Fifteen cells were reconstructed in wax, 

 ten after two micra serials and five after one micron serials, 



