XI] HISTORY l8l 



investigated the problem of the transmission of yellow fever 

 will always remain famous. During their investigations 

 Dr Lazear succumbed to the disease, but the research was 

 carried on by his fellow workers, who succeeded in proving 

 beyond all doubt that yellow fever is carried by the tiger 

 mosquito, Stegomyia fasciata. 



The earlier work of the commission was devoted to an 

 examination of the various bacteria that had been described 

 as the cause of the disease. Of these the most notorious were 

 Sanarelli's Bacillus ideroides, and Sternberg's Bacillus X, 

 which had been found in a certain number of cases. Reed and 

 Carroll found that both these bacteria played no part in the 

 aetiology of the malady, but were merely the result of a 

 secondary infection. Subsequently, in 1900, Reed, Carroll, 

 Agramonte and Lazear shewed that the disease could be pro- 

 duced in non-immune persons by the subcutaneous inoculation 

 of blood from an infected patient. They also proved that the 

 disease was not contagious but could only be spread by the 

 bites of infected 5. fasciata. These results have been thoroughly 

 confirmed by subsequent investigators. 



The work of the French Commission, composed of 

 Marchoux, Salimbeni and Simond, is the most important of all 

 subsequent researches on the disease, for these authors were 

 able to elucidate some of the necessary conditions for the 

 transmission of the malady. They also found that the first 

 generation of the offspring from an infected mosquito is 

 capable of infecting persons. Their results will be considered in 

 detail in the section devoted to a description of the mode of 

 transmission of yellow fever. 



The practical benefits that have resulted from the applica- 

 tion of the discovery of the mode of transmission of yellow 

 fever are only paralleled by those following Ross's work on 

 the development of Plasmodium in the mosquito. 



In the Panama Canal zone, which used to be one of the 

 worst endemic regions in Central America, as a result of anti- 

 mosquito campaigns the number of cases of yellow fever was 

 reduced so rapidly that within five years the disease had com- 

 pletely disappeared from this region. 



