Ranson, Degeneration in Spinal Nerves. 



283 



ation in the spinal ganglion. The possible factors which may 

 complicate the result are given in the footnote, on p. 275. 



II. The Influence of the Length of the Post-operative Period 



upon the Results. 



After the changes just described had been found in the rats that 

 had survived the operation for two months, the question arose 

 whether the degeneration had come to an end before the animal 

 was killed, and whether if the rat were allowed to live for a longer 

 period of time, further changes might not take place. It was 

 thought possible that the number of spinal ganglion cells might 

 further decrease, and that the roots might either continue to lose 

 fibers, or perhaps show a tendency to repair. 



TABLE VIII. 



Showing the Numerical Relations in the II C. Nerve in Rats which Lived Four 

 Months after Section of the Ramus Posterior of that Nerve when the Animals 

 were Twelve Days Old. 



TABLE IX. 



Showing the Influence of the Lapse of Time upon the Effect of Cutting the 



II C. Nerve.i 



Average Number of 



Ganglion Cells 



Ventral Root Fibers. 

 Dorsal Root Fibers . . 



2 Months After the 

 Operation. 



(5) 4.039 

 (4) 499 

 (4) 1.866 



4 Months After the 

 Operation. 



(2) 4,268 



(3) 574 

 (3) 1.933 



*The figures in parentheses indicate the number of cases from which the averages were obtained. 



From Table IX we see that the number of spinal ganglion cells, 

 although still far below the normal, is a little greater in the speci- 

 mens removed after four months than in those removed after two 



