160 BACTERIOLOGY FOR NURSES 



marshy lands, rainfall, polluted water, season, and 

 prevailing winds. Mosquitoes breed in marshy 

 places where the amount of moisture would vary with 

 the rainfall ; their time of breeding and development 

 coincides with the malarial season; and they are 

 carried considerable distances by the wind. 



Prophylaxis. — For generations malarial fevers 

 have been combated with repeated doses of quinine, 

 which is injurious and destructive to the young 

 parasites of malaria. For this reason the quinine is 

 given when the fever is declining, which is soon after 

 the young broods enter the blood. Persons suffering 

 from malarial fever should be shielded from further 

 mosquito bites, as the insects can only become in- 

 fected by sucking the blood of the malarial patient, 

 and if there are no infected rriosquitoes there will 

 be no malarial infection for other persons. 



The draining of lowlands and the application of 

 kerosene to standing water has rid many localities of 

 malaria by destroying the breeding places of mos- 

 quitoes; but the expense of such procedures is great, 

 and consequently not always practical. 



The screening of houses is one of the most effectual 

 methods of ' preventing malarial fevers. This way 

 shields the person suffering with the disease from 

 further bites, and as the Anopheles is not active until 



