ired to
be three quarters of a mile from the small towns to protect the village
inhabitants against fevers. There is no ground, however, for such a
requirement.

No evidence can be found that men who work in sewers and who breathe
sewer air all the time are especially unhealthy. Statistics show that
the laborers on the sewage fields of Paris and Berlin are actually
healthier than the average person living within those cities.

No reason can be assigned, based on our present knowledge of
bacteriology, why upturned earth or manured fields should be unhealthy
except as the breeding of insects may be encouraged thereby. The two
essentials, however, which should be considered are: first, the
topography or the formation of the soil in order that the surface water
may run off freely, and second, the character of the soil so that ground
water may not remain too near the surface. Whether the soil is rock or
gravel makes very little difference.

_Made ground._

One kind of soil, however, is distinctly objectionable, although,
fortunately, in the country such a soil is unusual: That is, a soil made
up of refuse, whether it be garbage, street sweepings from a near-by
city, or factory refuse.

The writer has in mind one enterprising landowner and farmer who offered
a near-by city the free privilege of dumping the city garbage on his
land. This was done for several years, and the low-lying districts of
his farm were all filled to a more advantageous level. This garbage was
then covered with about a foot of dirt and the land sold in building
lots to enterprising laborers determined to own their own homes.
According to the old theories of hygiene, the occupants of such houses
should have died like rats, but no particular excess of sickness in the
one hundred houses so located could be observed. One must, however,
believe, as we shall see later, that the repeated breathing of air drawn
from such polluted soil must be unhealthy, even though the mortality
records fail to show it.

It is interesting in this connection to note that the organic matter in
soil gradually disappears, just as a body buried in a grave will finally
decompose. Experiments show that such organic matter as wheat straw or
cloth in small pieces rots and decays in about three years. But this
depends very largely on an excess of air. If the soil is open and the
organic matter loose, oxidation takes place rapidly; but if a large pile
of organic matter is buried in