K. F. Meyer aa^ 



cernible, but in some sections clumps of bacilli are noted in the capillaries of the interlobular 

 vessels. It is reasonable to suspect that they are the seeds for the mctastic-cmbolic origin of 

 the abscesses. On the other hand, the bacterial aggregates in the alveoli of the right lower 

 lobe represent early stages of microbial localization which would ultimately have led to small 

 focal or even a lobular aspiration pneumonia. The extensive red and gray hepatization is 

 unquestionably induced by pneumococci. 



Mediastinal and Bronchial Lymph Nodes: The general engorgement of the capillaries and 

 the looseness of the follicles separated by dilated sinuses explains the edematous state of the 

 organ. Cortical as well as medullary sinuses are filled with amorphous material, a few leuco- 

 cytes, monocytes, and red cells. Pneumococci are readily demonstrable. 



Spleen: Engorgement of the venous sinuses with red-cell masses predominates to such an 

 extent that wide areas of the spleen resemble large hemorrhages. Although polyblasts and 

 lymphocytes are present, monocytes are numerous and predominate in the sinuses located 

 luider the capsule. The Malpighian bodies withoiU germinal centers are of a loose structure; 

 they are slightly enlarged and completely submerged in the masses of red cells. In a great 

 many areas of the spleen nucleated cells are only noted along the trabeculae and the penicilli. 



Intestinal Canal: Numerous hemorrhages are present in the villi of the duodenal and 

 jejunal mucosa. The lymphoid-tissue follicles show a loose arrangement and lack distinct 

 germinal centers. 



Liver: The mosaic of the liver lobides is frequently indistinct; the sinusoids are distended 

 and filled partly with amorphous material, red cells, occasional polyblasts, and monocytes 

 (pi. 2, fig. 4). In the periphery of the lobule many of the hepatic cells contain fine and large 

 fat droplets, some show nuclear necrobiotic changes while others are acidophilic and in a 

 state of dissolution. Throughout the columns the hepatic cells show a coarsely granular or 

 even a flaky cytoplasm; those adjacent to the central vein are in part studded with irregular 

 coarse particles of bile pigment. The Kupffer's cells contain hemosiderin. Bacteria are not 

 recognized despite careful search. The gall-bladder ^vall is slightly edematous; the mucosa is 

 normal. 



Portal Lymph Nodes: The capillaries are markedly distended and filled with red cells. 

 In the cortical and subcapsidar sinuses masses of red cells, polymorphonuclear leucocytes, 

 and monocytes are present. The secondary nodules of the lymph follicles are faintly visible 

 (pi. 2, figs. 5 and 6). Several of the medullary sinuses contain nests of epithelioid hyperplasia 

 first described by Fabyan^ in connection with his studies on the pathogenesis of abortus in- 

 fections in guinea pigs. An occasional cell contains one or two gram-negative coccoid rods. 



Kidneys: Both organs show in general the identical involvement, although the areas with 

 abscesses are more evident in the right kidney. Aside from an engorgement of the blood 

 vessels in the pyramids, the tubules are markedly dilated, filled with albuminous content 

 and occasional amorphous cluinps of pigment. As a rule, the glomerular tufts are normal 

 in size, in part filled with blood, in part collapsed, but the subcapsular space contains 

 albuminous detritus. In several renal corpuscles of many sections examined, the capsular 

 epithelium reveals a number of deeply stained cells protruding into the lumen of Bowman's 

 capsule (pi. 2, figs. 7 and 8). Under high magnification these cells contain clusters or morula- 

 like masses of gram-negative bacteria. These abnormal renal corpuscles arc in the vicinity 

 of extensive areas of cellular infiltration which may be located directly beneath the capsule 

 in the center of the cortex or even in the medullary substance (pi. 3, figs. 9 and 10). As a rule, 

 the center of such a zone contains one or several transverse sections of proximal convoluted 

 tubules with dark bluish or acidophilic cells attached to the basement membrane. These 

 cells are also seen in the lumen of the excretory ducts. 



Close examination of the bluish cells re\'eals that they have enclosed in their cytoplasm 

 irregular masses and nests of bacteria indistinguishable from typical Brucella organisms. 

 Many of these cells have a darkly stained round nucleus while in others various stages of 

 karyolysis attest to necrobiotic changes which have apparently taken place. The bacterial 



