THE FILTERABLE MICROBES 



369 



yellow fever. It was shown to be filterable by Reed, Carroll, 

 Lazear and Agramonte in 1901. It passes through the Chamber- 

 land "B" filter. It is rendered inert at 55 C. in 10 minutes and 

 even by standing at room temperature for two days. Yellow 

 fever is an acute febrile disease of man usually accompanied by 

 jaundice and sometimes by the vomiting of altered blood (black 



aft 



FIG. 144. Aedes (Stegomyla) colipus; female, a, Front tarsal claw. (After Reed 



and Carroll^) 



vomit). It is frequently fatal. Permanent immunity follows 

 recovery. The disease is naturally transmitted by a blood-suck- 

 ing mosquito, (Stegomyia, Aedes) calopus, which becomes capable 

 of inoculating the disease about twelve days after sucking blood 

 containing the virus. The mosquito probably remains infective 

 as long as it lives, and this insect thus becomes the essential reser- 

 voir of the virus of yellow fever. Prophylactic measures based 

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