ly becomes inoculated with bacteria. There is a much closer
relationship existing between the atmosphere of the cellar and that of
the house than is generally realized. An unclean cellar means
contaminated air throughout the house. When careful attention is given
to the sanitary condition of the cellar, many of the more common
diseases are greatly reduced. Cases of rheumatism have often been traced
to a damp cellar. In some localities where the cellars are unusually
unsanitary, there is in the season of spring rains, when they are
especially damp and contain the maximum of decayed vegetation, a
prevalence of what might be called "cellaritis." The symptoms differ and
the trouble is variously attributed, but the real cause is the same,
although overlooked, for, unfortunately, doctors do not visit the
cellar.

Cellars should be frequently cleaned and disinfected, using for the
purpose some of the well-known disinfectants, as formaline, bleaching
powder, or a dilute solution of carbolic acid. It has been found in
large cities, when the spread of such diseases as yellow fever was
imminent, that a general and thorough cleaning up of streets and cellars
with the improved sanitary conditions resulting greatly lowered the
usual death rate.

[Illustration: Fig. 67.--DUNG FUNGUS. (After BUTTERS.)

Often present on surface of unclean vegetables.]

284. Sunlight, Pure Water, and Pure Air as Disinfectants.--The most
effectual and valuable disinfectants are sunlight, pure water, and pure
air. Many kinds of microoerganisms, particularly those that are
disease-producing, are destroyed when exposed for a time to sunlight.
The chemical action of the sun's rays is destructive to the organic
material which makes up the composition of many of these organisms,
while higher forms of organic life are stirred into activity by it. The
disinfecting power of sunlight should be made use of to the fullest
extent, not only in the house, but plenty of sunlight should also be
planned for in constructing barns and other buildings where milk-and
meat-producing animals are kept. Pure water is also a disinfectant, but
when water becomes polluted it loses this power. Many disease-producing
organisms are rendered inactive when placed in pure water. Water
contains more dissolved oxygen than air, and apparently a portion of the
oxygen in water is in a more active condition than that in air. Pure
air, too, is a disinfectant; the ozone and hydrogen peroxide a