s to be constructed with
special care. It should be perfectly dry and provided with windows for
light and ventilation. Adequate means must also be provided, by sewage
pipes and other methods, for the disposal of all waste. Where drainage
pipes are provided, care must be taken to prevent the entrance of sewer
gas into the house and also the passage of material from these pipes into
the water supply. The placing and connecting of sewer pipes should, of
course, be under the direction of a plumber.

*The Water Supply.*--Since water readily takes up and holds the impurities
with which it comes in contact, it should be exposed as little as possible
in the process of collecting. Where cistern water is used, care must be
taken to prevent filth from the roof (Fig. 168), water pipes, or soil from
getting into the reservoir. Water should be collected from the roof only
after it has rained long enough for the roof and pipes to have been
thoroughly cleaned. The cistern should have no leaks (Fig. 169), and the
top should be tightly closed to prevent the entrance of small animals and
rubbish.

[Fig. 168]

Fig. 168--*Contamination of cistern water* by birds nesting in the gutter
trough.

Shallow wells are to be condemned, as a rule, because of the likelihood of
surface drainage (Fig. 169), and water from springs should, for the same
reason, be used with caution. Deep wells that are kept clean usually may
be relied on to furnish water free from organic impurities, but such water
often holds in solution so much of mineral impurities as to render it
unfit for drinking. The presence in water of any considerable quantity of
the compounds of iron or calcium makes it objectionable for regular use.

[Fig. 169]

Fig. 169--*Sources of contamination of cistern and well water.*
Illustration shows liability of contamination from surface drainage and
from entrance of filth at top.

*Hygienic Housekeeping.*--However carefully a house has been constructed
from a sanitary standpoint, the constant care of an intelligent
housekeeper is required to keep it a healthful place in which to live.
Daily cleaning and airing of all living rooms are necessary, while such
places as the kitchen, the cellar, and the closets need extra
thoughtfulness and, at times, hard work. Moreover, the problem is not all
indoors. The immedia