532 DR JAMES W. DAWSON ON 



system. Most French writers, among whom Phillippe and Jones may specially be 

 mentioned, have accepted this conception of Marie's, which, as can be seen, is a 

 deduction from Rjbbert's. 



Regarding the histological characters of the areas, Marie laid special stress on 

 the alterations in the blood-vessels and the persistence of the axis cylinders. The 

 external coat of the vessel is specially affected, and on this account the lumen 

 appears open and dilated in areas where the sclerosis is pronounced. The peri- 

 vascular sheaths are full of granular bodies. From the persistence of the axis 

 cylinders the following deductions are drawn : — (l) the absence of secondary degenera- 

 tion in the path of the nerve fibres ; (2) the remission, improvement, and even 

 cure which may occur, since the part of the nerve absolutely necessary for the 

 transmission of the nervous current is retained ; (3) it throws light upon the 

 pathology of tremor. 



Marie regards disseminated sclerosis as an interstitial process which has its 

 origin in the blood-vessels. Possibly the infectious agent itself, rather than the 

 materials which it secretes, brings this about, considering the dissemination of the 

 lesions and their essentially embolic character. The presence of fat granular cells at 

 the periphery of the islets points to the continued activity of the morbid process, 

 since the products of the degeneration of the nerve fibres are not yet fully absorbed 

 and are still being produced. 



Marie also points out that there are two forms of sclerosis : the one, in which the 

 foci have a clear-cut appearance and in which numerous axis cylinders are found 

 within the glia sclerosis ; and a second, with diffuse foci having very irregular and 

 deeply indented borders and in which axis cylinders as well as myelin sheaths have 

 often perished. He thinks that these two forms are distinct and are due to different 

 causes, though both are probably a sequelae of infectious disease. The latter is 

 referred to under the name of " diffuse multilocular sclerosis," and the classical 

 symptoms of disseminated sclerosis are frequently absent, especially the intention 

 tremor, disorders of speech, and the eye symptoms. Paralysis is more often present, 

 and its course is often rapidly fatal. 



Williamson (1894-1908). A brief description of the pathological anatomy of 

 disseminated sclerosis, as outlined by Williamson, has already been given. It 

 remains to be added here that this author strongly supports the view of an alteration 

 of the blood-vessel caused by a primary altered blood condition. The irregular 

 distribution of the sclerotic patches, without any relation to nerve tracts or nerve 

 fibres, seems to him suggestive of a primary change either in the blood or the blood- 

 vessels or lymphatics. The frequent presence of marked vascular changes, e.g. the 

 infiltration of the peri-vascular sheaths with round cells in the early areas, and the 

 sclerotic or hyaline thickening of the vessel walls in older areas; the presence of a 

 vessel with altered walls in the centre of an area; and occasionally the extension of 

 an area of sclerosis corresponding to the area of distribution of a blood-vessel, all 



