Mosquitoes and Yellow Fever 127 



he fully appreciated their significance. The dreaded 

 vomit soon appeared. I was too weak to see him again 

 in that condition, and there was nothing that I could 

 do to help him. 



"Dr. Lazear left a wife and two young children, one 

 of whom he had never seen." 



These experiments and many others like them 

 conducted on soldiers and Spanish immigrants 

 proved that this particular mosquito would trans- 

 mit the disease under certain conditions. 



1. The mosquito must bite the patient during 

 the first three days of the fever; after that a yellow 

 fever patient cannot infect a mosquito. 



2. A period of twelve days must elapse before 

 the mosquito is able to infect another person. 

 After that she may infect anyone she may bite; 

 that is, the germs remain virulent during the rest 

 of the mosquito's life. The French Yellow Fever 

 Commission working in Rio de Janeiro claim that 

 the first generation of offspring from such an in- 

 fected mosquito is capable of causing the disease 

 after they are fourteen days in the adult condition. 



The next step was to ascertain whether the dis- 

 ease could be contracted in any other way than by 

 the bites of infected mosquitoes. A camp named 

 Camp Lazear was established and the following 

 tests made : A mosquito-proof building of one room 



