642 DR JAMES W. DAWSON ON 



Areas in secondary disseminated sclerosis, on the other hand, are stated to be 

 of an " areolar " type : there is much greater involvement of the axis cylinders 

 and ganglion cells : there is seldom any sign of real sclerosis — only the remaining 

 glia network is present or a slight consolidation of it, which sets in concentrically 

 from the normal tissue, not excentrically from the abnormal glia predisposed to 

 proliferation : the blood-vessel changes are marked, and the dependence of the 

 areas on the altered vessels is striking ; and the foci are, as a rule, smaller in 

 size, are frequently followed by secondary degeneration, and are often limited 

 to the cord. Clinically, also, the disease occurs in definite relation to varied 

 toxi-infective processes : after a shorter or longer period the symptoms either 

 steadily progress or gradually recede to more or less complete recovery ; and 

 there is an absence either of any striking fluctuations during its course or of 

 any further relapses. 



In all the six cases examined by him, Mtjller found, histologically, a complete 

 absence of the undoubted components of inflammation, and, clinically, in eighty 

 cases, an absence of toxi-infective processes in the anamnesis. He therefore felt 

 justified in excluding exogenous factors and falling back upon developmental causes. 

 It is difficult to criticise so important and careful a work as Muller has given in 

 his monograph — the chapter on the diagnosis and differential diagnosis alone extends 

 to a hundred pages. It is there stated that more than twenty different diseases of 

 the nervous system may be simulated by disseminated sclerosis, that a typical case 

 is one of the most readily recognised diseases of the nervous system, but that 

 atypical forms constitute by far the greatest proportion. We are here more concerned 

 with the histological data, and these, as given in the monograph, are very slight. 

 Several staining methods are briefly mentioned, but reliance has been placed chiefly 

 on specimens lent to him and stained by Weigert's glia method, and also on 

 Weigert's myelin sheath and Marchi-stained sections. The latter showed at the 

 periphery of the areas an extending process, but all the areas examined in each case 

 showed a dense, compact glia structure, and nowhere was there any indication of 

 soft, i.e. early areas. 



In all the nine cases examined by me there have been present side by side with 

 dense areas, or forming an outer zone to such, very numerous foci in which transitions 

 could be traced from " early " areas with numerous fat granule cells — the criterion 

 taken by many writers for the existence of an inflammatory reaction, and which for 

 the present I accept — to areas of almost complete sclerosis in which there was no 

 indication even at the periphery of an advancing process. But such complete 

 sclerosis was comparatively rare : even in the most advanced case, many of the areas 

 showed the presence of fat granule cells in the walls of the vessels both within the 

 area and leading from it : and the great majority of the dense areas showed a central 

 sclerosis, gradually becoming less as it passed into the normal tissue, and this 

 transition zone gave the impression that had time been given it would have under- 



