WATER SUPPLY 
supply, should be analyzed, and all the surround- 
ings should be thoroughly examined. If your 
spring is analyzed as wholesome, and you are sure 
that it cannot be contaminated from some neigh- 
bor’s drainage, build over it aspring house, of stone, 
if possible, and in this have a stone box for keeping 
meats cool, and a tank for milk cans. 
Wells are contaminated not only by surface water, 
by slops, and by barnyard drainage, but by sub- 
terranean streams that encounter cesspools or other 
contaminating substances. In this way typhoid 
fever bacteria, as well as those which cause diarrhea, 
dysentery, and probably other diseases are carried 
into the human system. It is thought that such 
epidemics as cholera are frequently caused by pol- 
luted wells. A well must therefore not only be 
placed on high ground, but we must make sure that 
the under-soil strata do not seep toward it. The 
impervious strata may slope so as to run water under 
the soil for quite a distance and turn it into a well. 
The ground immediately around the well should 
slope away from it, and the waste water from the 
well itself should not be allowed to soak down into 
the ground, carrying with it surface impurities and 
stagnation. But you cannot even then be sure of 
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