66 Wisconsin Academy of Sciences, Arts and Letters. 



TABLE IX. 



Number of frog 



"Weight in grammes 

 Number of cells 



25 



115 

 11,137 



In Nos. 12 and 25 only the large cells were counted and 

 tlio numbers are therefore too small, Nos. 49, 18 and 43 are 

 male, 12, 14 and 25 female. The ovaries were removed from 

 the latter before weighing. Hence we may conclude that 

 there is a relation between weight and number of ganglion 

 cells not unlike that which obtains between weight and 

 motor nerve fibres. 



In the brachial region the cells are distributed in small 

 layers, each only one cell thick, and the spaces between the 

 layers are occupied by the outgoing fibres. In the lumbar 

 region no such arrangement is visible. The motor fibres of 

 the brachial region pass off at right angles to the cord, and 

 in the same way from the motor centre, while those of the 

 lumbar region pass off obliquely both inside and outside of 

 the cord. The most convenient method of showing the dis- 

 tribution of the cells is, therefore, that of taking a unit of 

 space and showing the number of cells in that. I have 

 chosen one-tenth mm. as the space^since it is small enough 

 to show the influence of the nerves and large enough to elim- 

 inate differences in thickness of the sections. I give the re- 

 sult in tabular form and graphically in plates I and II which 

 are to be compared with the tables. 



