Hatai, Spinal Ganglion Cells of Rat. 481 



liver (21 per cent, Greenwood, '04), weight of the body (10 

 per cent, Pearson, '97), weight of the heart (18 per cent. 

 Greenwood, '04), etc. I therefore corrected the values of 

 the mean, standard deviation, and coefficients of variation, 

 assuming that the theoretical curves represent more nearly the 

 true distribution of frequencies. On employing the values of 

 the theoretical ordinates there was found for cell-bodies, mean, 

 28.5948 micra, standard deviation, 14.8824 micra and coefficient 

 of variation, 18.36 per cent; while for the nuclei, the mean was 

 13.0535 micra; and standard deviation, 1.7929 micra; the coeffi- 

 cient of variation being 13.73 P^'^ cent. When these corrected 

 values are compared with uncorrected ones we find an increase 

 of 3 micra for the mean in both the cells and the nuclei, and a 

 reduction by 10 per cent in the coefficient of variation in the case 

 of the cells and a reduction by 4 per cent in the case of nuclei. 

 These corrected values appear to be the more probable, and are 

 the best we can obtain until some further means of correcting the 

 raw observations have been found. 



classification of the spinal ganglion cells. 



The unavoidable modification in the size of the spinal ganglion 

 cells due to the method of sectioning as here described suggests 

 a revision of the classification of the cells so far as it depends on 

 their observed sizes. It has been mentioned already that using 

 the size of the cells and the arrangement of the stainable masses 

 as criteria, several investigators have attempted to classify the cells 

 composing the spinal ganglion. Three such classifications pro- 

 posed by LuGARO, Lenhossek and Cox will be presented in 

 detail. 



LuGARO ('96) distinguishes in the dog five diff^erent varieties 

 of the spinal ganglion cells: 



1. Large cells with delicate, closely packed stainable masses 

 which are distributed uniformly throughout the cell-body. Around 

 the nucleus are large stainable masses closely packed. The nu- 

 cleus is large and clear and is provided with a nucleolus. These 

 cells appear to be numerous. 



2. Clear, medium-sized cells with irregularly formed small 

 and large stainable masses which are large at the periphery. Even 

 here we see that individual masses are not isolated but are united 



