THE HISTOLOGY OF DISSEMINATED SCLEROSIS. 537 



developmental theory is that from this kind of pathogenesis numerous forms of 

 disseminated sclerosis must be excluded. He, therefore, distinguishes between 

 primary disseminated sclerosis, due to developmental defect in some form, and 

 secondary disseminated sclerosis, the consequence of an acute disseminated myelitis. 

 This secondary form of disseminated sclerosis is only one of a group of allied diseases, 

 which includes advanced vessel disease and disseminated syphilitic disease of the 

 vessels, and all of which may lead to the formation of scattered sclerotic areas in the 

 central nervous system. Schmaus further thinks that diffuse forms of disseminated 

 sclerosis, or " diffuse multilocular sclerosis," in which the areas have not the defined 

 outline nor the characteristic preservation of the axis cylinders, found in true dis- 

 seminated sclerosis, must be regarded as " chronic myelitis." 



Ziegler, in the last edition of his text-book, also differentiated primary and 

 secondary disseminated sclerosis. Primary disseminated sclerosis may be due to the 

 incomplete development of the myelin at certain parts, or to glia abnormality in the 

 sense of an abnormal quantitative distribution of the glia, or deficient idioplastic 

 differentiation of the glia. The areas typical of primary disseminated sclerosis 

 contain dense sclerotic tissue, with persisting axis cylinders in the narrow meshes. 

 Secondary disseminated sclerosis is thought to be due to multiple ischsemic areas, 

 with secondary proliferation of the glia. The areas typical of this form are areolar, 

 and contain few axis cylinders in the widened meshes. 



Balint (1900), Bartels (1903), Probst (1898), Hoffmann (1902), and others 

 likewise speak of an abnormal or inherent disposition of the glia, an early 

 "invalidity" of the central nervous system, or an abnormal congenital " Veran- 

 lagung " of the glia. 



Muller (1904), in an important monograph, "Die multiple Sklerose des Gehirns 

 und Ruckenmarks," has made a careful survey of the whole subject of disseminated 

 sclerosis, especially in relation to its clinical course, differential diagnosis and patho- 

 genesis. He strongly support's Strumpell's view of the developmental nature of 

 the disease, and emphasises the distinction between primary and secondary dis- 

 seminated sclerosis. The views set forth in this monograph are more fully examined 

 in a later section (p. 638). In a later paper (1906) Muller urges the early diagnostic 

 importance of the ocular disturbances : affection of the optic disc, especially in 

 relation to the acuteness of vision and the field of vision, nystagmus, and paralysis 

 of the ocular muscles. He looks upon these as more valuable signs than the so- 

 called classical symptoms of the disease. The formes frustes are regarded as pre- 

 senting a typical syndrome which permits of their ready recognition. In a further 

 paper (1910) he relates the disturbances of sensibility, which are almost always 

 present, at least to a slight degree, to affections of the cranial and spinal nerve roots 

 in the glia-containing parts of their course. 



