488 'Journal of Comparative Neurology and Psychology. 



As will be seen from Fig. 4, the two curves agree very satis- 

 factorily. It is therefore concluded that there certainly exists 

 some definite mass relation between the cell-body and nucleus 

 and its relation is mathematically expressed by the parabolic 

 formula of the second order, as given. Since the regression is not 

 linear but is best represented by parabola we may say that gain 

 in the diameter of the nucleus following increase in the diameter of 

 the cell-body varies in every stage and although the curvature is not 

 pronounced from the nature of the parabola, the diameter of the 

 nucleus is relatively greater in the small cells than in the large cells. 

 For example, when the volume of the cell-body is compared with 

 that of the corresponding nucleus, the following relation is found: 

 In the cell-body whose diameter is 9 micra the volume of the same 

 is 2.64 times that of the nucleus, while in the cell-body whose diam- 

 eter is 47 micra its volume is 25.34 times that of the correspond- 

 ing nucleus. This fact indicates, as was mentioned already, a 

 predominant growth of the cell-body over that of the nucleus. 



This gives us a method for comparing at some future time the 

 relations in the small cells in the adult ganglion with that of the 

 small cells having the same size in the immature ganglion. 



CONCLUSIONS. 



We see from the preceding observations that: i. The method 

 of section modifies the true frequency distributions of the cells 

 and nuclei when their diameters are considered. 2. Under the 

 circumstances the skew curves of Type i for the cell-bodies and 

 that of the Type 4 for the nuclei may be considered the best and 

 most reasonable representation of the frequency distribution of 

 the diameters. 3. The theory that the entire group of small cells 

 with the structural characters of the large cells represents un- 

 changed small cells is probably erroneous in view of the unavoidable 

 modification of the large cells by the method of section. 4. The 

 diameters of the nucleus and that of the cell-body are highly and 

 positively correlated (r = 0.8616). 5. There exists a definite 

 mass relation between cell-body and nucleus, and the diameter of 

 the nucleus corresponding to any given diameter of the cell-body 

 is best represented by a parabola of the second order. 6. The 

 spinal ganglion cells in a given ganglion may be considered as a 

 homogeneous group, so far as the size is concerned. 7. Spinal 



