﻿EXPLANATION OF MAP. 



The map is intended to illustrate the spread of the epidemic of dengue through 

 the post of Fort William McKinley, Rizal Province, P. I. 



The letters placed opposite the barracks indicate the company occupying them, 

 and the figures accompanying the letters indicate the order in which the barracks 

 were infected. It will be observed that barracks widely separated became infected 

 before others in apposition, and that the last barracks to become infected were 

 those of the Eighth Cavalry. 



The red line indicates tl e course of a small stream of water which is an ideal 

 breeding place for mosquitoes. 

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