Hardesty, spinal Ganglion Cells. 41 



This shows it possible that some of these extra ganglion cells 

 may send processes toward the periphery alone and thus con- 

 tribute to the distal excess. It is further seen in the columns 

 that if the cells of the ganglion increase in number, their increase 

 does not keep pace with that of the distal excess, nor does the 

 number of cells in excess of those giving origin to dorsal root 

 fibers bear a constant relation to the fibers forming the distal 

 excess. 



As to tlie origin of the distal excess, it is indicated in the 

 number relations noted above that it can hardly be due to any 

 one cause. To explain its existence little can be added in this 

 paper to that which was advanced in the previous papers. There 

 are very {qw publications which even consider its presence, but 

 certain of the findings of several investigators upon the struc- 

 ture of the spinal ganglia may be interpreted toward its ex- 

 planation. 



One of the first explanations which suggests itself is that 

 the excess may be due to the splitting of fibers on the distal 

 side of the spinal ganglion. This was one of the first evidences 

 sought for by the author. Both methylen blue intra vitam, 

 and gold chloride were employed in the preparations and serial 

 sections as well as teasing were resorted to. The Vth and Vlth 

 nerves were chiefly used for this because they are the smaller 

 of the nerves used in this paper and because the smaller nerves 

 have the higher percentage of distal excess. 



A bifurcation of the fibers on the peripheral side of the 

 ganglion was observed quite often but by no means was it ob- 

 served in sufficient frequency to at all explain the entire origin 

 of the distal excess. To give a distal excess of even 10%, 

 every tenth root fiber must bifurcate at the peripheral border of 

 the spinal ganglion and, while with the methods employed it 

 was impossible to determine the exact proportion of dividing 

 fibers, the author is convinced that it cannot occur even as fre- 

 quently as this. It is seen in the tables that the smaller nerves 

 always have a distal excess above \0% and that it may even 

 exceed 50%. Most of the splitting observed occurred within 

 the level of the peripheral border of the ganglion, and in order 



