552 DR JAMES W. DAWSON ON 



the disease. He thinks that as these very psychoses which are claimed as types of 

 endogenous etiology are marked by the presence of cobra reaction, the fact of its 

 presence in disseminated sclerosis appears to support the view of the endogenous 

 nature of this disease, especially as it is very seldom observed in acquired disease of 

 the nervous system, with the exception of general paralysis. 



Robertson (1912) records a case of disseminated sclerosis which is of special 

 interest on account of the presence of hydromyelia, interstitial neuritis in several 

 peripheral nerves, and changes in the posterior root ganglia, which suggested a 

 chronic inflammatory condition. The absence of some of the characteristic features 

 of disseminated sclerosis, e.g. nystagmus, scanning speech, intention tremor, etc., is 

 explained by the author by the fact that the sclerosis had confined itself chiefly to 

 the cord, the medulla and pons being only slightly affected, and the cerebrum and 

 cerebellum scarcely at all. The presence of a hydromyelia is interesting in view of 

 the theory that disseminated sclerosis is a multiple gliosis, but the author thinks 

 that the cavity formation might as truly occur in glial tissue, formed as a result of 

 chronic irritation, as in that resulting from congenital abnormality, and that the 

 well-marked interstitial peripheral neuritis lends support to the view of the chronic 

 toxsemic nature of the disease. The appearances of the posterior root ganglia would 

 also accord with this view. There were no degenerative changes in the walls of the 

 blood-vessels, but there was evidence of a cellular reaction in their adventitia. 



Wohl will (1913) has given a short review of the recent literature on disseminated 

 sclerosis. The pathological anatomy, pathogenesis, and etiology are carefully 

 discussed, and various etiological factors are submitted to a close examination. The 

 conclusion is reached that histological investigation has advanced in the direction of 

 harmonising our ideas as to the exogenous nature and vascular origin of the disease, 

 but that we are still far from determining its real nature. 



III. 

 METHODS. 



In order to obtain as comprehensive a view as possible of the distribution of the 

 lesions and of their structure, a very large number of sections, both large and small, 

 have been examined from the brain and spinal cord of each case. The brain was 

 fixed in Pick's solution, and, after the tissue had acquired a certain consistency, was 

 cut into pieces suitable for the respective methods. The spinal cord, after small 

 pieces at various levels had been removed for Cajal's silver method for axis cylinders, 

 was also placed in Pick's solution. 



The cerebral hemispheres were removed from the pons and cerebellum by a section 

 at the upper margin of the pons at right angles to the transverse fibres of the pons. 

 They were then separated from one another by a vertical sagittal section. Each 



