Two Different Ways in which Yellow Fever 



may be Transmitted 



By the Culex Mosquito (Stegomyia Taeniata) ^ 



Had it been known in 1881 when I reported my first inoculations with 

 contaminated mosquitoes, that eight or ten drops of blood from a yellow 

 fever patient injected under the skin of a non-immune would almost surely 

 produce an attack of the disease, as Dr. Reed and his colleagues have now 

 clearly proved, my discovery of the transmission through the bite of the 

 culex mosquito would have been considered quite plausible. 



My experiments would have been taken up and repeated under more 

 satisfactory conditions, the number of mosquitoes required in order to 

 produce a characteristic reaction would have been ascertained, and, 

 probably, twenty years of ignorance on that important subject would have 

 been spared to the medical profession. Without stopping to discuss the 

 nature of the specific germ, the bare knowledge of the fact that the prick 

 of a needle, previously moistened with the lymph of a smallpox or varioloid 

 vesicle, suffices to produce an attack of variola, would have induced my 

 colleagues to interpret my experimental results in accordance with my 

 own ideas. After the infecting bite upon a yellow fever patient some of the 

 germs contained in the blood are likely to remain attached to the parts 

 constituting the sucking apparatus of the insect, so that when the same 

 mosquito is allowed, two or three days later, to bite a non-immune the said 

 germs may be deposited along the track of the wound or washed down into 

 the wounded capillary vessel by the saliva or venom which is usually 

 discharged during the biting and sucking operation. I had at first 

 experienced some difficulty in fitting this interpretation to an essential 

 condition stipulated in my "mosquito theory", namely, that the insect 

 which should transmit the disease must belong to a particular species, 



1) The Journal of the American Medical Association, Nov. 23. 1901. Revista de 

 Medicina Tropical, Habana, Nov. 1901, t. II, p. 185. 



