PATHOLOGICAL HISTOLOGY 169 



easy to demonstrate thrombosed capillaries or blood vessels 

 of pre-capillary size in these lesions. The cells consist of mono- 

 nuclear phagocytic cells (endothelial leucocytes), lymphoid 

 cells, plasma cells, mast cells, and eosinophiles in small num- 

 bers and polymorphonuclear leucocytes. The lesions are most 

 common in the pyramids but occur also in the cortex, where 

 they are often in contact with glomeruli. Capillaries adjacent 

 to or involved in the lesions are often packed with endothelial 

 cells and lymphoid and plasma cells. Hemorrhage into the 

 interstitial tissues and into tubules of the pyramids are con- 

 stantly present in kidneys with these acute lesions. Twenty- 

 six cases of our series showed these lesions. In the cases that 

 did not show them are represented post mortems from the 

 seventh to the eighteenth day of typhus. 



We found no lesions of large blood vessels in the kidney. 

 In one case there were small mural thrombi in small arteries 

 in the sub-mucosa of the pelvis of the kidney and in this case 

 both the large and small forms of rickettsia were found in 

 groups in the endothelium of the affected vessels. 



Lesions of the glomeruli in the form of an intracapillary pro- 

 liferation of the endothelium were present in nine cases, in 

 one case they were sufficiently marked to be accompanied by 

 degeneration of the convoluted tube and to warrant calling 

 the condition a glomerular-nephritis. This case died on the 

 twentieth day of the disease and was one with unusually severe 

 cerebral lesions. The glomerular reaction cannot be regarded 

 as characteristic of typhus. We have observed the same re- 

 action in other infectious diseases, recently in a series of post 

 mortems upon influenza cases. 



The adrenals: No lesions distinctive of typhus were found 

 in the thirty-seven cases. In no instance were vascular lesions 

 found. Twenty-six adrenals showed lesions of the cortex com- 

 mon to infectious diseases in general. These lesions show as 

 small areas of disappearance of the cortical cells, glomerular 

 and fasicular zones, with accumulations of small numbers of 

 endothelial leucocytes, lymphoid, and plasma cells. (Plate 

 XVII, fig. 44.) 



