Ranson, Degeneration in Spinal Nerves. 289 



IV. Effect of Reunion of the Cut Ends of the Divided Nerves. 



It is clear from Table IV that, so far as the survival of spinal gan- 

 glion cells is concerned, it is a matter of indifference whether 

 regeneration of the nerve occurs or not. In four cases no regenera- 

 tion occurred at all ; in the other six cases the extent of the regenera- 

 tion varied considerably; in one case (14) an almost perfect nerve 

 was found, with only a slight thickening to indicate the point of 

 division. But with this wide range in the degree of the restoration 

 of the peripheral nerve, there is no difference in the condition of 

 the spinal ganglion. This shows very clearly that the degenera- 

 tion of spinal ganglion cells is not markedly influenced by the 

 regeneration or lack of regeneration of the peripheral nerve. 

 Marinesco ('98) states that unless there is union of the divided 

 ends of the nerve, the motor cells of the ventral cornua do not 

 pass from the phase of reaction to the phase of restoration, but 

 atrophy and disappear. The entrance upon the phase of restora- 

 tion is, according to hmi, an mdication that regeneration has begun 

 in the nerve. Van Gehuchten ('99) and Foa ('99) have been 

 unable to confirm these observations of Marinesco for the motor 

 nuclei, and my results would indicate that for the spinal ganglia 

 the restoration of the cells is entirely independent of the restoration 

 of the peripheral nerve. 



CONCLUSIONS. 



As a result of dividing a peripheral nerve, there occurs not only 

 the typical Wallerian degeneration of the distal portion but also 

 various changes in the proximal portion of the nerve, the spinal 

 ganglion, the ventral and dorsal roots and the spinal cord. In 

 all these regions there take place both a simple atrophy and a true 

 degeneration. The atrophy results in a decrease in the size of 

 the fibers, many of which entirely lose their medullary sheaths. 

 Many of the cells of the ventral cornua and of the spinal ganglion 

 are markedly atrophic. The degeneration in the fibers proximal 

 to the lesion begins some weeks later than Wallerian degeneration, 

 from which, however, it cannot be distinguished histologically. This 

 retrograde degeneration affects only a part of the fibers and can 

 be found not only in the central stump and the ventral and dorsal 

 roots but also in the intramedullary continuations of the root fibers. 

 This results in a distinct diminution of the number of nerve fibers 



