DISTBIBUTION OF DISEASE GERMS 99 



it has made. If the person has malaria, the mosquito secures 

 blood which may carry malarial germs ; and if these germs 

 are present, they multiply rapidly within the mosquito, really 

 living in quite a different way as compared with their life in 

 the human blood. Some of the germs get into the mosquito's 

 salivary glands. When the infected mosquito bites another 

 human being, some of the malarial germs may be injected into 



FIG. 54. The malarial mosquito (Anopheles) 

 Male at left ; female at right. After Howard 



the wound with the salivary fluid. These germs may grow and 

 increase in number, and sooner or later produce the disease 

 in a person who had not previously had it. 



113. How to destroy mosquitoes. Since malaria and some 

 other diseases are carried only by mosquitoes, it is evident 

 that if we can remove the mosquitoes, we shall be free from 

 danger of infection. These insects pass through the early part 

 of their life in ponds, lakes, and quiet water. If this water 

 is drained away, mosquitoes cannot reproduce. Where such 



