MULTIPLE NEUROMATA OF THE CENTRAL NERVOUS SYSTEM. 761 
nodules, with a commencing thickening of the vessel-wall, not only of the vessel in 
which the nodule was present, but to a lesser extent of all the vessels of the cord. The 
lower part of the 6th cervical segment in Weigert-fuchsin preparations gives the 
appearance, under low power, of a normal cord with the vessels, even the capillaries, 
markedly prominent, owing to the slight thickening of their walls. At a slightly 
lower level, where a small nodule is evident on one side and a few abnormal strands 
on the other, the angles of the grey matter are picked out by a commencing fibrosis. 
When we pass to the 7th and 8th cervical segments, where the nodule forma- 
tion in the anterior white matter is marked, this stain shows diffuse pink areas, 
within which are strands of myelinated fibres, many of which are on the point of 
disappearance even with the most careful differentiation. A comparison of numerous 
sections shows that these areas of fibrosis are associated with the breaking up of 
nodules, and that these have been first involved in, or have at least first yielded to, 
the compression of the increasing fibrosis and the influence, toxic or otherwise, which 
first called it into play. 
In such sections, when the fibrosis is not sufficiently dense to have involved all the 
structural elements, there is present a meshwork of fine fibres which suggests the 
presence of capillaries running in all directions. These are, however, finely-calibred 
bands, recognised as nerve fibres by the yellowish staining of their protoplasm, the 
occasional faint trace of axis-cylinder, and the fact that they never contain any red 
blood cells. 
With the increasing fibrosis the pia, pial septa, and grey matter all show an intense 
perivascular infiltration with cells, whilst in the areas of fibrosis such cells form small 
accumulations and extend into the surrounding nerve tissue. Most of these cells are 
of the lymphocyte type, with a darkly-staining nucleus in which no definite structure 
can be recognised, and with a very narrow zone of protoplasm. Some cells, slightly 
larger than these, are also present, with an oval nucleus, placed to one side, in which 
the chromatin network can be recognised, especially with polychrome methylene-blue 
staining. A few plasma cells, with characteristic radkern nucleus and meta- 
chromatic-staining protoplasm, are scattered amongst the other cells. 
Gla Cells.—In the zone of extension of the fibrosis, an intense glia-cell prolifera- 
tion and hyperplasia have occurred (figs. 7 and 49). The cells contain oval or 
irregular nuclei, which are much larger than those in normal glia cells and are situated 
at the periphery of the cell. The nucleus stains darkly but the chromatin network is 
distinct, with large nodule points, often a distinct nucleolus, and always a sharply 
contoured membrane. ‘The protoplasm varies in amount: in the smaller cells it is 
homogeneous, of very varied shape, and with very fine processes; in the larger cells 
it assumes an angular or star-like form, and from the angles pass thick ramifying 
processes which form a network enclosing in its meshes numerous lymphocyte cells. 
Many of the glia cells are in close relation to vessel walls, especially capillaries. It is 
in this zone of advancing fibrosis that there are found elements the interpretation. of 
TRANS. ROY. SOC. EDIN., VOL. XLVIII. PART III. (NO. 27). 109 
