188 PATHOLOGY OF TYPHUS IN MAN 



actual demonstration. The number of phagocytic cells -having 

 the appearances of ordinary macrophages indicates that many 

 of the cells are of endothelial origin. The relationship of the 

 proliferative lesions to capillaries is easily shown here as else- 

 where. Capillaries with endothelial lesions and thrombosis 

 are common. Perivascular accumulations of lymphoid cells, 

 plasma cells, and phagocytic mononuclear cells (macrophages, 

 endothelial leucocytes) occur in the substance of the posterior 

 lobe and in the dural investment. 



(u) The Gasserian ganglion: One Gasserian ganglion was 

 sectioned from each of twenty-six cases. Lesions due to typhus 

 were found in fifteen, these lesions include capillary lesions 

 with and without adjacent proliferative lesions, perivascular 

 infiltrations and reactions of the capsular cells following 

 ganglion cell degeneration. 



The proliferative lesions are in the nerve trunks as well as in 

 the ganglion cell areas, and are composed of cells indistinguish- 

 able from many cells composing the " compact 7 ' (p. 180) 

 type of lesion in the brain. These cells are probably of endothe- 

 lial origin and they frequently contain inclusions of other cells. 

 Perivascular accumulations of lymphoid cells, plasma cells, 

 and phagocytic mononuclear cells (macrophages, endothelial 

 leucocytes) with rare polymorphonuclear leucocytes and mast 

 cells are found in the nerve trunks and the arachnoidal invest- 

 ment of the ganglion. 



Degenerative changes in ganglion cells are common and are 

 attended by swelling and proliferation of the capsular cells. 

 Complete disappearance of ganglion cells leaving a residuum 

 of Nissl granule dust in spaces nearly filled by proliferated 

 capsular cells is frequent in ganglia with extensive lesions. 



The proliferation of capsular cells and degeneration of gan- 

 glion cells is not unlike that of rabies, though less striking. A 

 diffuse infiltration with lymphoid cells, plasma cells, and 

 macrophages of considerable areas of the ganglion is common 

 and such areas usually include one or several degenerated 

 ganglion cells with capsular proliferation. 



