THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 543 



Taylor notes that various types of lesion may co-exist in the same case : sharply 

 defined clean-cut areas in contrast to a more diffuse type, in which the area shades 

 off into the normal. He follows Williamson's explanation of the sharp delimitation 

 of the process in certain areas by suggesting the presence of a toxic agent, of 

 unknown character, but with a special affinity for myelin, which spreads from a 

 central focus until it exhausts itself. This causal agent reaches the tissue in all 

 probability by the blood or lymph channel, but its manifestation may occur without 

 evidence of local inflammation. 



Marburg (1906) in an important monograph, "Die sogenannte akute multiple 

 Sklerose," gives a report of three cases and a review of others recorded in literature 

 of disseminated organic disease of the nervous system which, from their resemblance 

 to disseminated sclerosis, both clinically and pathologically, have been described as 

 acute or subacute multiple sclerosis. The disease occurs usually between the ages of 

 twenty and thirty. The symptoms indicate that there are multiple lesions in the 

 brain and spinal cord ; the onset is gradual ; there is no fever ; and though the 

 affection is progressive, there is a tendency to remission and fluctuation in the 

 symptoms. In the majority of the cases recorded, death occurred within three 

 months, in some cases earlier, in some later. 



The author considers that this so-called acute multiple sclerosis is a form of true 

 multiple sclerosis which is characterised by a more rapid course of the disease. The 

 symptoms indicate that it is a form of multiple sclerosis, especially the mode of 

 onset, the advance of the disease in stages, the remissions and intermissions, and the 

 indications of multiple lesions. 



The pathological changes are characterised by degeneration of the medullated 

 sheath of the nerve fibres, while the axis cylinder is relatively intact. At the same 

 time, or soon afterwards, there is proliferation of the neuroglia cells and of cells in 

 the walls of the blood-vessels. The process is analogous to peri-axial neuritis. 



The pathological changes are inflammatory, and belong to the group of 

 degenerative inflammatory changes. The nature of the degeneration of the 

 medullated sheath of the nerve fibres indicates that it is due to a " lecitholysis," 

 such as can be produced experimentally by "ferment" action. The pathological 

 changes may, therefore, be regarded as the result of a toxin, and their final stage is 

 the complete replacement of the degenerated nervous tissues by a finely fibrillated 

 neuroglia tissue, which contains only few nuclei. 



The affection'is regarded by Marburg as a form of degenerative myelitis, and he 

 suggests for it the name of " encephalo-myelitis periaxialis scleroticans." 



Wegelin (1906) records a case which shows the great difficulty of drawing the 

 distinction, emphasised by Muller, between the acute cases, following disseminated 

 encephalo-myelitis, and the true " sclerose en plaques." The disease in this patient 

 ran a very rapid course, and at the autopsy typical areas of sclerosis were found 

 disseminated through the brain and spinal cord, and in the upper three dorsal 



