266 'Journal of Coinparative Neurology and Psychology. 



very well analyzed by van Gehuchten ('03) and briefly sum- 

 marized by the present writer ('04). It is also believed that we 

 may omit without loss any mention of the theories of the different 

 investigators concerning the nature and cause of the cellulipetal 

 alterations resulting from the section of nerves. 



In studying the literature on retrograde degeneration in the 

 spinal nerves, it was found convenient to arrange the results of the 

 different investigators in tabular form, placing the changes found 

 in the various parts of the nervous system in separate columns 

 under the following headings: central stumps of the severed 

 nerves, ventral roots, dorsal roots, spinal ganglia, the spinal cord 

 in general, the ventral horns and motor cells, the dorsal horns and 

 the dorsal funiculi. In this way were tabulated the changes found 

 in sixty-nine autopsies upon cases of more or less long standing 

 amputation. In a separate table of the same kind were summar- 

 ized the changes observed by eighteen different investigators who 

 had carried out experimental amputation and nerve resection in 

 animals. When these tables were completed, it was possible to 

 compare the results of the different investigators and see what 

 changes were constant in any part of the nervous system. It is 

 with reference to these tables that the following has been written, 

 and for this reason it has been possible to make accurate, but at 

 the same time very general, statements. 



The first observation of an alteration propagated centrally along 

 the course of an injured nerve was made in 1829 by Berard, who 

 noticed that the ventral roots, associated with the nerves of an am- 

 putated limb, were smaller than their fellows on the opposite side. 

 But it was not until 1868-69 ^^""^^ Vulpian and Dickinson aroused 

 general interest in the subject, an interest which has led to an 

 almost uninterrupted series of investigations and even at the pres- 

 ent time has not abated. The results of this series of investiga- 

 tions may be stated rather briefly. 



In a considerable proportion of the cases, no notice was taken of 

 the central stumps of the severed nerves. Of those who did in- 

 clude these structures in their investigations only two found them 

 normal (Friedreich '73, and Dreschfeld '79). The complete 

 degeneration, seen in one of Dickinson's ('68) cases, was undoubt- 

 edly due to extraneous causes, probably septic infection. In all the 

 other cases of amputation a simple atrophy, associated with a 

 marked decrease in the average diameter of the nerve fibers, pre- 



