THE FOREST AS A SANITARY AGENT 65 
with silent sawmills and stranded population. Such 
a land, although capable of producing useful wood- 
crops forever, is worn out in appearance, unproduc- 
tive, and unfit for human habitation. 
7. Tuer Forest as a Sanitary AGENT 
The importance of the forest as a sanitary agent 
is usually underrated. In affording a place where 
the busy brains of the world may find rest and diver- 
sion, the forest performs a beneficial service to man- 
kind. It performs also a very important sanitary 
function in affording clear, pure water to large cities. 
Water, to be good in quality and regular in quantity, 
should come from an uninhabited forested watershed. 
Upon the purity of such water depends the healthful- 
ness of the millions of people who live in cities. 
Stagnant water and organisms of disease are rare 
in the forest. In the Dismal Swamp of Virginia, for 
instance, the water is healthful, while in the surround- 
ing burnt-over pine land, with here and there stag- 
nant pools of water, malaria is common. Malarial 
diseases follow in the wake of forest destruction. 
Clearing new land in many places causes malaria. 
It is the experience of travelers in tropical countries 
that fever is generally worse in the open districts. It 
is not in the forest but in the land inhabited by in- 
fected individuals that malaria is common. 
