48 ANIMAL BIOLOGY 



nected with the malady ; and one of the old medical writers 

 mentions as a characteristic of malaria seasons that 'gnats 

 and flies are apt to be abundant.' . . . 



"Malaria was formerly considered to be a form of ague 

 due to foul air, whence its name, which literally means ' bad 

 air.' It was attributed to a sort of ' miasma.' Its true 

 nature did not become known till 1880, when Laveran, a 

 French military surgeon, working, at the time, in Algeria, 

 discovered the malarial parasite in human blood." Major 

 Ross, an English officer in India, later proved the presence 

 of the parasite in the body of the mosquito. 



39. Transmission of malaria. — Investigation has shown 

 that the parts of the world where Anopheles abound are the 

 eastern half of the United States and a large part of Europe, 

 together with many regions of the tropics. It is a well- 

 known fact that these are the regions, too, in which malaria 

 is very abundant, and this is the first line of proof that the 

 Anopheles mosquito is always responsible for the trans- 

 mission of malaria. 



Even more conclusive were the experiments of four investi- 

 gators who spent the fever season in the dreaded malaria 

 district of the Roman Campagna. They built for themselves 

 a carefully screened house in which they remained from sun- 

 set to suiprise, and this was the only precaution that they ob- 

 served. In the daytime they went freely among those who 

 were stricken with the fever, they allowed themselves to be 

 soaked with the falling rains, and at night the air from the 

 swamps came freely into their sleeping quarters. But while 

 hundreds of malaria cases were all about them, not one of the 

 four contracted the disease. Hence, to escape malaria, one 

 has only to make sure that Mrs. Anopheles is prevented from 

 injecting her billful of malaria germs — and this she does 



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