186 PATHOLOGY 



method of transmission. Members of the Yellow Fever 

 Commission of the United States Army slept for weeks 

 on the bedding of yellow fever patients, slept with the 

 patients, nursed them, and subjected themselves to 

 every possible chance, but did not take the disease while 

 mosquitos were excluded. Mosquitos were allowed to 

 bite patients with the disease and afterward healthy 

 individuals, and the disease followed, Dr. Lazear dying 

 from an attack. Colonel Gorgas by exterminating 

 mosquitos stamped out yellow fever in Havana. 



Morbid Anatomy. The skin is jaundiced and hemor- 

 rhages occur from the skin and mucous membranes, 

 especially the mucous membrane of the stomach, where 

 it gives rise to the distinctive black vomit of the disease. 

 The lymphatic glands are enlarged and there is fatty 

 degeneration and areas of necrosis in the liver. The 

 kidneys show diffuse nephritis. 



Morbid Physiology. The fever, profound prostration, 

 and the serious injury to the liver and other internal 

 organs would indicate the presence of a toxin in this 

 disease, but none has been isolated. Immunity is 

 established by an attack. This, however, may be a 

 germicidal rather than a toxic immunity. 



MEASLES 



Definition. An acute contagious disease, character- 

 ized by catarrhal inflammation of the upper air-passages 

 and a specific eruption of the skin. 



