EXCRETION 
463 
becoming contaminated. Some of the smaller towns have 
not yet come to appreciate the value and importance of hav¬ 
ing pure water to drink. The result is frequent epidemics of 
sickness. 
In Figure 410 is shown a model reservoir for a small town. 
The reservoir is located on a high piece of ground and all 
possible sources of surface drainage have been eliminated. 
The surroundings are graded so that standing water cannot 
Figure 410. — A Model Reservoir. 
accumulate and become impure to flow later into the reser¬ 
voir. In Figure 411 is shown a reservoir in which the con¬ 
ditions are the reverse. The water is stored in a place sur¬ 
rounded by residences and swampy ground on the left of 
the photograph. The open channels in the grass are streams 
that empty into the water of the reservoir. One of these is 
supplied from the overflow of water of the Erie Canal. This 
alone is sufficient explanation of why there have been fre¬ 
quent epidemics in the town that has this water supply. 
What are the conditions surrounding the water supply of 
your home ? 
In the country, the water is taken from wells and springs, 
which are splendid sources of water when properly protected 
