Hatai, Ganglion Cells in the Rat. 



121 



the original describer) are not numerous enough to explain the 

 relations found. 



VI. The Size of the Cell Body, the Nucleus and the 

 Fibers at Different Ages. 



Twenty of the largest cells with theirnuclei, and twenty of 

 the largest fibers, were selected for the measurement in each case. 

 In the case of cell-body and nucleus, three of the largest cells 

 with nuclei from each section, 12// thick (10.3 and 24. 5 grams), 

 and two of the largest cells from each section, 12/^ thick (68. 5 and 

 167 grams), were selected for the measurement, while in the 

 case of the fibers, twenty of the largest fibers from one section 

 in each case were measured. The following table shows the 

 results thus obtained. 



TABLE VIII. 



Showing the mean diameters of the cell-body, nucleus and fibers 

 at different ages. 



The cell-body is thus seen to be growing constantly from 

 10.3 grams to maturity. The cervical spinal ganglion contains 

 the largest cells in each stage, the lumbar comes next in rank, 

 while the thoracic shows the smallest size among the three. In 

 the rats between 68.5 and 167 grams, the mean diameter of 

 the cervical spinal ganglion cells enlarges less than that of the 

 lumbar, while the thoracic and lumbar are nearly alike. The 

 comparison ot the cell-body and nucleus shows that the 



