ord about water purification. Where the quality of
the water supply is not above suspicion it may be improved by
filtration. A filter should never be installed without the advice of a
qualified expert, for there are numerous worthless devices and few
really efficient ones. Where a filter is not available, the water used
for drinking should be boiled or sterilized if there is the slightest
doubt as to its wholesomeness.

CHAPTER III

=Purifying Water by Copper Sulphate=

From the standpoint of the health of the community, the most vital
problem is to get pure water. Almost equally important, when comfort
and peace of mind is considered, is the procuring of sweet water. The
wise owner of a country home looks to the water supply upon which his
family is dependent. The careful farmer is particular about the water
his stock, as well as his family, must drink. But careless persons
constitute the large majority. Most people in the city and in the
country pay no attention to their drinking water so long as it "tastes
all right."

_Clear Water Often Dangerous_

Some years ago the inhabitants of Ithaca, N. Y., furnished a pitiful
example of this foolhardy spirit. For a year previous to the breaking
out of the typhoid epidemic, the public was warned, through the local
and the metropolitan press, of the dangerous condition of Ithaca's
water supply. Professors of Cornell College joined in these warnings.
But the people gave no heed, probably because the water was _clear_
and its taste sweet and agreeable. As was the case in this instance,
bacteria are tolerated indefinitely, and it is only an alarming
increase in the death rate that makes people careful. Then they begin
to boil the water--when it is too late for some of them.

_Bad-Tasting Water not Always Poisonous_

But let the taste become bad and the odor repulsive, and a scare is
easily started. "There must be dead things in the water, or it
wouldn't taste so horrible," is the common verdict. Some newspaper
seizes upon the trouble and makes of it a sensation. The ubiquitous
reporter writes of one of "the animals" that it "looks like a wagon
wheel and tastes like a fish." With such a remarkable organism
contaminating one's drink no wonder there is fear of some dread
disease. The water is believed to be full of "germs"; whereas the
pollution is entirely due to the presence of algae--never poisonous to
mankind, in some cases acting as purifying agents, but at