68 



The subcapsular hmph sinus is not very distinct, though to some 

 extent it may be recognized. The trabeculse are thickened; their 

 connective tissue is poor in nucleated cells and consists mostly of 

 wav}' fibers. The larger arteries show considerable hypertrophy of the 

 adventitia. The Malpighian bodies can hardly be recognized. The 

 accumulation of l}Tnphoid cells around the terminal arteries forming 

 these bodies has become much rarified, the boundaries of the cells 

 have almost completely disappeared, and they are gradually lost in 

 the surrounding tissue. With a low power no pulp spaces can be 

 distinguished, but with high magnification the original ones can 

 be recognized, at least here and there, as narrow clefts. The predom- 

 inating cell element in these sections is the mononuclear type, 

 with a vesicular nucleus, a reticular chromatin, one or more nucleoli, 

 and a protoplasmic body, generally of medium and frequently of 

 considerable size. These cells are clearly proliferated lymphatic 

 endothelia derived from those which lined the original normal pulp 

 spaces. Therefore, the great increase in volume of the spleen is to 

 be attributed mainly to an endothelial proliferation, as several 

 writers have previously described in certain cases of primary 

 splenomegaly (among them the author of this report). A con- 

 siderable number of pohmuclear neutrophiles are also found in the 

 pulp spaces, as well as some mononuclear plasma cells. Eed blood 

 corpuscles are present to a certain extent, though they are not so 

 numerous as in an equal area of a normal spleen. Some of the 

 larger mononuclear endothelia are phagocytic, containing red or 

 white blood corpuscles, or both. (jSTone were seen which included 

 plague bacilli.) Here and there in the sections one sees dense and 

 more or less irregular masses about 20 to 30 /a or more in diameter, 

 which show a marked afiinity for the eosin stain. It was first 

 believed that these were peculiar cells, but it was finally decided 

 that they were composed of deformed, agglutinated red blood corpus- 

 cles, sometimes including a mononuclear or pohTiuclear leucocyte. 

 Plague bacilli generally arranged in small groups were found in 

 the pulp spaces or in the outer parts of the ill-defined follicles. A 

 search for the Donovan-Leishman bodies was negative. Liver : The 

 interlobular hepatic tissue is increased and some of the liver lobules 

 show marked atrophy. The septa between the acini exhibit both old 

 connective tissue fibers without nuclei and nucleated inflammatory 

 cells. Most of the latter are mononuclears of the small l}Tnphoid 

 t3-pe. Plasma cells are seen only very rarely, but ordinary poly- 



