of the cellar and provide an
air-tight floor over the cellar bottom. Methods of doing this will be
discussed in the next chapter.

_Moisture in soils._

The presence of water in the soil has usually been considered to be
unhealthy because of the impression that it led to certain fevers. The
writer has heard, for instance, of an attack of malaria being caused by
a short visit to a damp vegetable cellar; and it is one of the triumphs
of the century that the malarial parasite has been discovered, and the
old theory of the dangers of moisture been done away with. A damp cellar
has always been considered to be undesirable, but just why nobody
knows. A damp cellar causes molds to form rapidly, thus destroying
vegetables and other material which might naturally be stored there, but
that the presence of moisture in a cellar in itself produces any organic
emanation leading to disease is not true, although dampness is essential
to the growth of certain organisms.

In the latter part of the nineteenth century, Dr. Bowditch, of Boston,
showed that consumption developed most where the surrounding soil was
moist, and generally it is the impression that dry air is the only
proper air for a consumptive person to breathe. This theory, however, is
being rapidly exploded, and patients now remain outdoors in any weather,
and no kind of air is objected to by physicians, provided it is outdoor
air. Some little time ago the writer was called by a Board of Health to
investigate a certain swamp which had some odor, was considered a blot
on the landscape in an unusually picturesque village, and was said to be
responsible for a long list of contagious diseases. A house-to-house
inquiry in the vicinity showed that among some dozen families, only one
illness in the last few years could be remembered, and that was an old
lady who had been on the verge of the grave for forty years.

It is curious to note the many examples which are cited by the earlier
sanitarians to prove the dangerous effect of damp soil. For example,
Pettenkofer, a very prominent German hygienist, says that in two royal
stables near Munich, with the same arrangements as to stalls, feed, and
attendance, and the same class of horses, fever affected the horses very
unequally. In one stable, fever was continually prevalent; in the
other, no fever was found. Horses sent from the unhealthful to the
healthful stables did not communicate the disease. The difference
between the two pl