32 Journal of Comparative Neurology and Psychology. 



sympathetic neurones and to send processes toward the peri- 

 phery without sending a corresdonding process into the dorsal 

 root. Another cause for the excess of cells above the fibers 

 being less on the distal side of the spinal ganglion, is due to 

 the bifurcation of fibers on the distal side. Both this and the 

 multipolar cells of the character just mentioned contribute to 

 the formation of the excess of fibers on the distal side of the 

 ganglion and both will be considered in the discussion of the 

 "distal excess." 



On neither side of the spinal ganglion does the number of 

 cells per each fiber supposedly connected with the ganglion 

 show a regular decrease with the increase in the body weight of the 

 specimens. Such a decrease might be expected with the usual 

 conception that the number of ganglion cells becomes fixed at 

 quite an early period in the growth of the animal, but my counts 

 for neither of the three spinal nerves here represented show 

 such with any regularity. Hatai ('02) found in the rat an ap- 

 preciable decrease in the value of the ratios of cells to dorsal 

 root fibers as the animal reached maturity. Either in this re- 

 spect the processes of growth in the frog are again different, or 

 the process is so slow in the frog as to require the investigation 

 of a greater number of nerves of a greater number of individ- 

 als. Could the cells be counted at different periods of the 

 growth of the same frog, the result might be different, for it 

 must be remembered that each set of figures in Table I but 

 represents the conditions in 'the nervous system of a different 

 individual at a certain time. 



The growth relations are shown in another way in Table II 

 which is constructed with reference to the body weights instead 

 of grouping with reference to the number of the spinal nerve 

 as in the table above. Such results as may be brought out by 

 arranging the frogs into two groups, one containing the larger 

 and the other the smaller frogs, and summating the numbers in 

 each will be presented later. 



