248 William Christopher Krauss 



tutes the bulk of the nerve fiber. The perineurium and en- 

 doneurium also take part in this process and become converted 

 into thick layers of connective tissue. 



The neuritic processes following the infectious diseases, 

 especially diphtheria, afford good examples of the parenchy- 

 matous form of neuritis. Fig. 3 shows the oculo-motorius 

 nerve in a case of diphtheria, the seat of marked degenerative 

 changes.* Many of the axis cylinders have disappeared, while 

 others are smaller and have lost their sharpness of contour. 

 The white substance of Schwann has absorbed the staining 

 fluid indicating some changes in regard to chemical com- 

 position. 



In discussing the various forms of muscular atrophy, we 

 have only described diseases and conditions in which wasting 

 of the muscles was a prominent symptom not by any means 

 characteristic or pathognomonic. Othersymptoms were always 

 present which denoted more forcibly than the atrophy the 

 seat of the disease or cause of the wasting. In the following 

 types the atrophy of the muscles is the predominant sign, so 

 much so that these affections have been designated pro- 

 gressive muscular atrophy and progressive muscular dys- 

 trophy. 



Myopathic Atrophies. —The myopathic forms of muscular 

 atrophy are universally designated as progressive muscular 

 dystrophy, after the recommendation of Erb of Heidelberg. 

 They include several analogous types clinically and perhaps 

 pathologically, although the focal lesion has not been ulti- 

 mately determined. They develop in the young, are relative- 

 ly rare and as yet the exact pathology is undetermined. Erb 

 is of the opinion, recently expressed, that there may be some 

 slight changes in the ventral cornua as yet undiscovered, and 

 that the myositis or lipomatosis is really secondarj- to organic 

 changes in the nervous system. 



Erb's juvenile form is the most prominent tj'pe of the 



* See Author's paper on Diphtheritic Paralysis in Neurologisches Ceu- 

 tralblatt. No. 17, 1888. 



