Chapter III. 
PROPHYLACTIC METHODS BASED UPON THE DESTRUCTION OF 
MALARIA MOSQUITOES. 
In the prophylaxis of the malarial infections the following meas¬ 
ures have been found efficient in practice: 1. The destruction of 
the mosquitoes transmitting the infection; 2. The protection of man 
from the bite of mosquitoes; 3. The destruction of the malaria 
plasmodia while in the blood of man. Theoretically, any one of these 
methods would be sufficient to prevent malarial disease could it be 
applied in an ideal manner, but practically, it is but seldom that 
one is successful without the aid of the others, and it is generally 
necessary to combine them all in order to achieve the fullest success 
in the prevention of malaria in any locality. 
In this chapter will be considered those methods of malaria pro¬ 
phylaxis that depend for their success upon the destruction of the 
mosquitoes transmitting the disease, and in applying these methods 
it is necessary that one have knowledge of the life history of the 
Anopkelincp, to the extent comprised in the data given in the pre¬ 
ceding chapter. It is obvious that before applying most of the 
methods mentioned in this chapter it will be necessary to make a 
mosquito survey of the locality one is working in, thus determining 
whether malaria mosquitoes are present or not, their breeding places, 
and the preventive methods most applicable and economical for the 
region investigated. 
The prophylaxis of malaria by the destruction of mosquitoes is 
the ideal method of prophylaxis where conditions are such as to render 
the destruction of these insects practicable, but in the military service 
such methods must necessarily be restricted to more or less permanent 
camps or to permanent posts, as most of them are impracticable upon 
the march or in camps of short duration. In many regions in the 
United States where military posts are located it is believed that the 
malaria present could be entirely eradicated by the adoption of meth¬ 
ods looking to the destruction of mosquitoes, and this may also be 
true of isolated instances in our tropical possessions, but in most 
regions, especially in the Tropics, the most that we can hope to accom¬ 
plish in the way of mosquito destruction is to greatly reduce the num¬ 
ber of the insects, and in such localities other methods of prophylaxis 
must be used in conjunction with the destruction of the mosquito. 
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