154 PATHOLOGY OF TYPHUS IN MAN 



each instance by the discovery of important histok)gical 

 lesions specific of typhus. 



In the majority of the cases the myocardium showed no 

 gross change beyond minute pale areas and lines evident only 

 upon close inspection and microscopically; the hearts from all 

 cases which died before convalescence showed some lesions. 

 Acute lesions of the heart valves and macroscopic mural 

 thrombi of the heart were not found. 



(d) Blood vessels: The histological study of our cases shows 

 that the large blood vessels occasionally are the seat of acute 

 lesions specific of typhus. Such lesions in all probability are the 

 foci upon which extensive thromboses form. We found one case 

 of each of the following: Thrombosis of the superior mesen- 

 teric artery with infarction of the small intestine; thrombosis 

 of the left internal carotid artery with massive cerebral sof- 

 tening of the left hemisphere; thrombosis of a main branch of 

 the left pulmonary artery; thrombosis of the main branches 

 of the splenic artery with infarctions; mural thrombi of the 

 aorta and common iliac arteries. 



(e) The spleen: The spleen of cases which died before the 

 end of the second week, in most instances, was enlarged. The 

 consistency was firmer than in typhoid and the cut surfaces 

 remained smooth. The color of freshly cut surfaces was dark 

 red or maroon-colored. In the third week the spleens were 

 usually within the normal range of weight, even in the presence 

 of severe or confluent bronchopneumonia. Table XV gives 

 the weights of the spleens from our series of autopsies with the 

 ages of patients, day of disease, and important complications 

 which might affect the weight of the spleen. 



(f) Lymph nodes: In cases uncomplicated by important in- 

 fections, no gross changes were found in the lymph nodes. 



(g) Bone marrow: Marrow from the middle third of the 

 femur was taken from each case. Thirty-six of the thirty- 

 eight typhus cases showed some degree of reaction, varying 

 from a red mottling of the outer zone to a firm red marrow of 

 non-fatty consistency. Histologically, the red portions of the 

 marrow are actively erythroblastic. This reaction of the 



