526 DR JAMES W. DAWSON ON 



picture. Most observers who have had the opportunity of examining cases clinically 

 and anatomically have noted the disparity between the anatomical change and the 

 disturbance of function. From the days of Charcot onwards this has been related 

 to the persistence of the axis-cylinder and the comparative integrity of the ganglion 

 cells in a sclerosed patch, with the consequent absence of secondary degeneration. 



II. 

 HISTORICAL. 



The lesions in disseminated sclerosis were figured by Cruveilhier in his Atlas 

 d'anatomie pathologique (1835-1842), and the condition was first clinically 

 described by Frerichs (1849). Rjndfleisch (1863) carefully examined the morbid 

 anatomy : both Cruveilhier and he representing the lesions under the name " grey 

 degeneration." The disease, however, was not generally recognised until Charcot 

 published his famous lectures (1866). Charcot, working at the Salpetriere, may be 

 said to have given the classical account of the disease, both in its clinical manifesta- 

 tions and its anatomical features. The three cardinal symptoms — intention tremors, 

 nystagmus, and scanning speech, — when present, were considered as diagnostic of 

 disseminated sclerosis, and what may be regarded as the three cardinal and essential 

 points of the anatomical picture — absence of myelin sheath, neuroglia proliferation, 

 and persistence of the axis cylinders — were no less certainly thought to be distinctive 

 of this disease. It has been named by the French writers " sclerose en plaques 

 disseminees," by the Germans " Herdsklerose," and the appropriate and expressive 

 term " insular sclerosis" was proposed by Moxon. 



Since the time of Charcot, however, it has come to be recognised that the 

 essential clinical features are the grouping of certain symptoms and their variability. 

 Pathologically, too, it is now recognised that the anatomical features, once thought 

 to be distinctive of disseminated sclerosis, may be the final stage of quite different 

 processes. In the Introduction it has been stated that the two groups of theories 

 put forward to explain the nature of the morbid process may be classified as 

 Exogenous and Endogenous. As the latter term has come to bear a wider signi- 

 ficance than that first attributed to it, it has been thought advisable to refer to it 

 under the name "Developmental." The term "exogenous" must be admitted to be 

 synonymous with " inflammatory," using this word in its widest sense, as a 

 reaction process. 



In the following survey of the literature, the writers will be referred to under the 

 following groups : — those who support the inflammatory nature of the process, those 

 who support its developmental nature, and a final group including the more recent 

 investigators. It will be sufficiently evident that the views of many recent workers 

 cannot be precisely defined. 



