unprotected food, where they cause fermentation changes and the disease
germs multiply. In considering the sanitary condition of a locality, the
character of the soil is an important factor. Whenever there is reason
to suspect that a soil is unsanitary, it should be disinfected with lime
or formaldehyde. Soils about dwellings need care and frequent
disinfecting to keep them in a sanitary condition, equally as much as do
the rooms in the dwellings.[99] In the growing of garden vegetables,
frequently large quantities of fertilizers of unsanitary character are
used, and vegetables often retain mechanically on their surfaces
particles of these. To this dirt clinging to the vegetables have been
traced diseases, as typhoid fever and various digestion disorders.

289. Disposal of Kitchen Refuse.--Refuse, as vegetable parings, bones,
and meat scraps, unless they are used for food for animals or collected
as garbage, should preferably be burned; then there is no danger of
their furnishing propagating media for disease germs. Garbage cans
should be kept clean, and well covered to protect the contents from
flies. Where the refuse cannot be burned, it should be composted. For
this, a well-drained place should be selected, and the refuse should be
kept covered with earth to keep off the flies and absorb the odors that
arise from the fermenting material, and to prevent its being carried
away by the wind. Lime should be sprinkled about the compost heap, and
from time to time it should be drawn away and the place covered with
clean earth. It is very unsanitary to throw all of the kitchen refuse in
the same place year after year without resorting to any means for
keeping the soil in a sanitary condition. Although composting refuse is
not as sanitary as burning, it is far more sanitary than neglecting to
care for it at all, as is too frequently the case.

Ground polluted with kitchen refuse containing large amounts of fatty
material and soap becomes diseased, so that the natural fermentation
changes fail to take place, and the soil becomes "sewage sick" and gets
in such a condition that vegetation will not grow. Failure to properly
dispose of kitchen refuse is frequently the cause of the spread of germ
diseases, through the dust and flies that are attracted by the material
and carry the germs from the refuse pile to food.

[Illustration: FIG. 70.--PLUMBING OF SINK.

1, 1, house side of trap, filled with water; 2, vent pipe; 3, drain pi