Mosquitos and Yellow Fever 541 



of the blood of an individual suffering from the non-experi- 

 mental form of the disease. 



7. The period of incubation in thirteen cases of experi- 

 mental yellow fever has varied from forty-one hours to five 

 days and seventeen hours. 



8. Yellow fever is not conveyed by fomites, and hence 

 disinfection of articles of clothing, bedding, or merchandise, 

 supposedly contaminated by contact with those sick with the 

 disease, is unnecessary. 



9. A house may be said to be infected with yellow fever 

 only when there are present within its walls contaminated 

 mosquitos capable of conveying the parasite of this disease. 



10. The spread of yellow fever can be most effectually 

 controlled by measures directed to the destruction of mos- 

 quitos and the protection of the sick against the bites of 

 these insects. 



n. While the mode of propagation of yellow fever has 

 now been definitely determined, the specific cause of the 

 disease remains to be discovered. 



The probability that Bacillus icteroides is the specific 

 cause and is transmitted by the mosquito is so slight that it 

 need scarcely be considered. All analogy points to the 

 organism being an animal parasite similar to that of malarial 

 fever. 



Concerning the prophylaxis of yellow fever, Guiteras * 

 has studied the effect of intentionally permitting non- 

 immunes who are to be exposed to the disease, to be ex- 

 perimentally infected by being bitten by infected mosquitos, 

 after which they are at once carefully treated. His first 

 conclusion was that "the intentional inoculation gives the 

 patient a better chance of recovery," but the danger of 

 death from the experimental injection was later shown to 

 be so great that it had to be abandoned. 



* "Revista de Medicina Tropical," Havana, Cuba, 1902. 



