2l6 BACTERIA, YEASTS, AND MOLDS 



they can pass from one person to another, and conse- 

 quently malaria is not a contagious disease. This fact 

 has been known for many years, and no instances of 

 direct contagion have been noted. 



The last few years, however, have disclosed the fact that 

 there is a means by which malaria is transmitted indi- 

 rectly from man to man, and have shown us how the 



FIG. 70. a, the harmless mosquito (Culex) ; b, the malarial 

 mosquito (Anopheles), a' and a" show the position of the 

 harmless mosquito when lighting on the floor or on the 

 wall ; ', b" and b'" show the position of Anopheles when 

 lighting on the floor, wall, and ceiling. 



human body usually becomes infected with this disease. A 

 certain kind of mosquito (Fig. 70, b) forms an interme- 

 diate connection between a malarial patient and another 

 individual. This kind of mosquito may bite the patient, 

 sucking into its body at the time a considerable quantity 

 of blood. Inasmuch as the blood contains the malaria para- 

 sites, the mosquito will become filled with them. The little 

 organisms live in the mosquito as readily as they do in the 



