133 



Why the latter are not readily tlistinguishable is easily explained 

 by the microscopic examination of the organ, which frequently shows 

 small follicles indistinct in outline, owing to the fact that the cells 

 forming them are lost in the surrounding pulp spaces. The latter 

 themselves are generally not distinct and are occluded by cellular 

 elements, consisting of red blood corpuscles and nucleated leuco- 

 cytes. In a considerable number of our cases the spleen gave 

 evidence of an extensive proliferation of the endothelial cells of 

 the pulp spaces. Sometimes great numbers of these are seen, many 

 of them containing two or more nuclei. A number of them are 

 phagocytic and include either other cells or plague bacilli. As 

 already stated, in all of our cases the spleen showed an invasion 

 with bacilli, so that we are much inclined to look upon this as a 

 regular occurrence in plague. 



THE GENITO-URINARY SYSTEM. 



It had already been emphasized by Aarchow that in plague the 

 genito-urinary system often presents subserous and submucous hem- 

 orrhages. This is the common observation of all who have studied 

 the pathology of the disease, and it is also confirmed by our work. 

 As a whole the kidneys invariably show marked congestion, and 

 even to the naked eye evidences of parenchymatous degeneration 

 are never absent. On the cut surface there are seen uriniferous 

 tubules which are greyish-white or grayish-yellow as well as dull, 

 and engorged vessels, among which are the glomerular capillaries. 

 The Malpighian tufts are usually observed as intensely red points, 

 although at times they may appear as more or less solid, grayish- 

 red masses. This latter «,ppearance may easily be overlooked 

 until our attention has been drawn to it by a microscopic examina- 

 tion, M'hich fully explains why one might expect to see such solid, 

 grayish-red, swollen glomeruli. 



A microscopic change which has been described by all who have 

 studied the kidney in plague is profound cloudy swelling of the 

 epithelium of the uriniferous tubules, with the presence of granular 

 or hyaline material in the latter. 



HYALINE FIBRIN THROMBI OF THE GLOMERULAR 



CAPILLARIES. 



However, a very characteristic change in the kidneys which we 

 have found in seven of our twenty cases, has not, it appears, before 

 been described, namely, a hyaline fibrin thrombosis of the glomeru- 



