GROSS PATHOLOGY 153 



viewing reflected portions of the skin by transmitted light. 

 Hemorrhages of considerable size were frequently found in the 

 subcutaneous fat in sites subjected to slight trauma, e.g., 

 hypodermic injections and bony prominences. Large areas of 

 necrosis of the skin (gangrene), whether or not symmetrically 

 distributed, were not accompanied by thrombosis of large 

 vessels. Microscopical study of the skin necroses has shown 

 that the non-symmetrical necroses are due to thrombosis of 

 capillaries and small arteries and veins beginning in the corium 

 arid extending centripetally. This process may result only in 

 small firm elevated yellowish red areas reminiscent of cutaneous 

 gummata or in deep sloughs involving the whole depth of the 

 subcutaneous fat and even the muscles (Autopsy No. 36) 

 (Fig. 9). Stasis due to pressure apparently favors the locali- 

 zation of the endangeitis characteristic of typhus. The sym- 

 metrical gangrene of the extremities is probably due to nerve 

 lesions; we had but one case of this sort at post mortem 

 (Autopsy No. 26). 



(b) The organs of circulation and blood formation: The blood 

 is commonly stated to be dark and slow to coagulate. In 

 general this proved to be the rule in our series. Clots in the 

 heart were almost invariably small and soft and frequently 

 the heart's blood was without clot as late as three hours post 

 mortem; but, on escaping into the pleural cavity it formed 

 a fairly firm coagulum. We noted no change in the viscosity 

 of the blood. 



(c) The heart: As a rule the left ventricle was contracted, 

 and the right moderately dilated. The auricles, and particu- 

 larly the left, were usually distended with blood. The myo- 

 cardium in six cases which died, without important bacterial 

 complications, between the ninth and twelfth days of the 

 disease, showed pallor, loss of consistency, and yellowish 

 streaks and points. These six post mortems were done soon 

 after death and post-mortem changes were excluded. In a 

 few other cases with confluent bronchopneumonia the same 

 condition of the myocardium was found. The interpretation 

 of the gross appearance of these hearts was substantiated in 



