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THE CAUSES OF DISEASE. 279
caught in large, clean cisterns, and carefully preserved
for all domestic uses. Filtered through alternate layers
of sand and charcoal, it is the purest and sweetest water
we can have. It is even better to take the trouble of
distilling water, than to use such as is hard.
Water containing vegetable and animal impurities and
animalculae, may introduce morbid matters into the sys
tem. Fresh, cold spring water, or clean, well-preserved
rain water, however, contains no animal life. Water,
to contain animalculae, must have been exposed to light
and warmth, and contain, also, some or vegetable ani
mal matter.
Causes of disease, of more or less are potency, found
in the atmosphere, in what is called malaria, which
simply means bid air, but is used to designate
the un
known cause of many endemic and epidemic diseases.
There seems much reason to believe that some of these
diseases are caused by
telluric or aromal causes, so
subtle as not to be influenced by atmospheric changes
and motions.
Carbonic acid gas, if a poison, is still more a mechan
ical cause of illness or death. In a well, a mine, or a
close room, it displaces the atmosphere, and produces
asphyxia, by hindering
us from breathing. We drown
in this as heavy gas,
in water. In each case we die for
want of breath. It kills us just as it out a puts candle,
by preventing the access of oxygen.
A well is freed
from it by putting in which absorbs it in
quick-lime,
being converted into a carbonate. The means of resus
citation are the same as in drowning, only that cold
water may be dashed over the body, while after drowning
we try to restore warmth.