236 Dr. F. W. Mott. Brains of Men and Animals [Mar. 14, 
Every stage of the development of these plasma cells from lymphocytes 
can be observed in the brain tissues, also in the chronically inflamed 
lymphatic glands. Likewise, in chronic cases, morular cells, indicative of 
chronic inflammation, can be seen in most cases. 
From the clinical notes furnished in these cases, it is apparent that there 
is a correlation between the severity of the symptoms, the chronicity of 
the disease and the degree and intensity of the chronic inflammatory 
process, as evidenced by the abundance of lymphocytes in the peri-vascular 
spaces and in the subarachnoid space, also by the number of plasma cells and 
morular cells. 
With regard to the ganglion cells, the very chronic cases show a very 
marked degeneration of the ganglion cells of the central nervous system, 
particularly of the medulla oblongata and the cortex—proportional to the 
degree of affection of the vessels—many of the smaller of which are ccm- 
pletely occluded, partly by the accumulation of lymphocytes, partly by the 
proliferation of the nuclei of the endothelial cells. Many of the capillaries 
are completely occluded by this process, and the result is not merely a 
chromatolysis of the ganglion cells, but a coagulation necrosis and destruc- 
tion. Where there is this advanced degeneration, there is a marked 
proliferation of the glia cells, and a large number of spider cells can be seen ; 
in fact, the appearances, as the accompanying pictures show, closely resemble, 
in many respects, the chronic inflammatory changes met with in general 
paralysis. Except that, whereas in the latter disease, the vascular change 
is In great measure secondary to the degenerative change of the ganglion 
cells; in Sleeping Sickness the chronic inflammatory process is universal 
throughout the central nervous system, and the ganglion cells are destroyed, 
secondarily to the occlusion of vessels. 
The glia cell proliferation is not nearly so pronounced in Sleeping 
Sickness, because there is so much less wasting of the brain substance. In 
one case, so marked was the peri-vascular infiltration in the grey matter 
of the cortex, that after hardening in Miiller’s solution the vessels could be 
seen with the naked eye as glistening pearly lines and points. 
In the blood contained in the vessels of a few of the chronic cases 
without micro-organismal infection, a solitary trypanosonie or a portion of a. 
trypanosome could very occasionally be seen, but it 1s a remarkable fact 
how very seldom, in the immense number of sections examined, I have been 
able to find evidence of trypanosome infection by examination of the blood 
contained in the vessels; I have, therefore, concluded that these organisms 
cannot be abundant, and that if they produce this chronic inflammation as 
all the facts in the etiology of the disease prove, it may either be that they 
