656 DR JAMES W. DAWSON ON 



agent must be at work, although such intoxications maybe important as predisposing 

 factors in the production of a toxic arteritis. 



(e) Infections and Endogenous Intoxications. — Toxi-infective agents have long 

 been held of primary importance. Pierre Marie has urged the recognition of acute 

 infective disease as the actual final cause of disseminated sclerosis, which he believes 

 arises on the basis of multiple inflammatory vessel alterations brought about by the 

 infective agents of scarlet fever, measles, diphtheria, small-pox, puerperal fever, 

 pneumonia, erysipelas, typhoid fever, cholera, etc., in combination with the organisms 

 which produce a mixed infection. Many other writers have favoured the view of the 

 relation of acute infectious disease to disseminated sclerosis, but Hoffmann has 

 strongly opposed it, and Krafft-Ebing in an analysis of a hundred cases found this 

 factor in the anamnesis only six times, and no organisms that can have any causal 

 relationship to the disease have ever been identified, either in the blood, the cerebro- 

 spinal fluid, or the tissues. 



Malaria. — Several cases of disseminated affection of the central nervous system 

 in consequence of malarial infection have been reported, chiefly by Spiller and by 

 Italian writers. These arise probably on the basis of a mechanical closure of the 

 cerebral and spinal vessels by the parasites which form solid thrombi. This merely 

 shows that malaria may be followed by a disseminated disease of the central 

 nervous system, and such cases tend to recover more surely than cases of true 

 disseminated sclerosis. 



Tubercle and syphilis are both generally admitted to have no significance in the 

 etiology. Syphilis may produce disseminated areas in the central nervous system, 

 but the histological characters of these have, as a rule, nothing in common with 

 those of disseminated sclerosis, in which disease also the reactions in the serum and in 

 the cerebro-spinal fluid and the cytological examination of the latter are all negative. 



Endogenous intoxications are of a very varied nature, and include not only the 

 toxins engendered within the body by bacteria, but also auto-toxins caused through 

 abnormal metabolic or assimilative processes and those the result of deficient or 

 abnormal secretions. Systematic investigation of metabolic changes in disseminated 

 sclerosis have not yet been undertaken, nor has any toxin of any nature been isolated 

 either from the blood or the cerebro-spinal fluid. Investigations of the bio-chemical 

 changes, analogous to those found in para-syphilitic affections, have thrown little 

 light on the disease, but investigations along this line have not been extensive. 



It is the unsatisfactory and contradictory result of each of the above-mentioned 

 factors that has led numerous writers to seek for one common cause which will 

 explain the real nature of the disease. Klausner, in a careful analysis of a hundred 

 and twenty-six cases of disseminated sclerosis, has come to the conclusion that few of 

 the alleged causal factors are of any importance. Muller, from the large number 

 of causes postulated, has drawn the inference that none of these can be the essential 



