170 BACTERIOLOGY FOR NURSES 



The disease has been reproduced by the injection 

 of a portion of blood ; taken from a yellow-fever 

 patient, into a susceptible person. 



For centuries it was supposed that the disease was 

 carried by contact. In 1900, following the Spanish- 

 American War, a United States Army Commission 

 was appointed to investigate the cause and modes 

 of transmission of yellow fever, which resulted in 

 finding proof of the method of infection, although 

 the cause is still unknown. 



Several years prior to 1900, Dr. Carlos Finlay of 

 Havana had advanced the theory that yellow-fever 

 infection is carried by mosquitoes, and taking this 

 theory as a basis the Commission proved without 

 question that infection is carried only by a certain 

 species of mosquito, Stegomyia fasciata, in the same 

 manner as the Anopheles carries the parasite of ma- 

 laria. The doctors of the Commission reared the 

 mosquitoes from eggs, and then allowed them to 

 bite yellow-fever patients, and later to bite non-im- 

 munes who had been quarantined and could not pos- 

 sibly have contracted yellow fever in any other way. 

 Of twelve non-immunes ten contracted yellow fever. 



In later experiments seven men lived for twenty 

 days in a mosquito-proof house ; these men slept in 

 the soiled garments of yellow-fever patients, but no 



