52 MOSQUITOES 



are active and penetrate rapidly into the tissue of the 

 salivary duct and so iuto the proboscis of the mosquito, 

 and, with the saliva or poison, they enter the blood of the 

 next warm-blooded animal which the mosquito bites. It 

 is then supposed that tlu; blasts enter the red blood cor- 

 puscles and the development re-be<^ins at the sta^e where 

 we took it u]). 



It is thus shown that the full development of the mala- 

 rial parasite cannot take place within the human body ; 

 that the Anopheles mosquitoes are necessary secondary 

 hosts ; that the sexual s'eneration of the parasite takes 

 place only in mosquitoes of the i^enus Ano})heles ; and 

 further, that the old ideas of malaria from l)ad air (and of 

 course the word iiKilnrid means bad air), swamp '" miasma," 

 and so on, are to the minds of those familiar with the 

 subject of the biology of these low forms of life com- 

 pletely overturned. 



Eeasoniiig- from the life history of the parasite alone, as 

 observed, would not, however, satisfy the minds of ])eoi>le 

 at large, and, in fact, it did not satisfy many medical men 

 who were not esi)ecially familiar Avith this field of bio- 

 logical research. Very many jjractical denumstrations 

 have therefore been made. One of tlie most interesting 

 was that carried on by Professor (irassi, the Italian, 

 during the summer of 1900, in the Plain of Cai)pacio, near 

 Salerno. The objects of this experiment were: (1) To 

 atlbrd an absolute proof of the fact that malaria is trans- 

 mitted exclusively by tlie bite of Anopheles mosquitoes ; 

 (2) To found, on the results of recent lesearch, a code 

 of rules to be adopted for freeing Italy from malaria 



