ly alternative is water gathered from areas
that are owned by the individual and on which, therefore, all dwellings
may be prohibited, all cultivated land avoided, and where the primeval
forest may be restored, making the watershed equal to that from which
forest streams emerge.

But usually, in the case of a single house, it will not be possible
entirely to eliminate the dangers of surface pollution, although an
inspection will show the dangers, and possibly some of them may be
avoided. Certainly any direct drainage into the streams should be cut
out, as well as the drainage from barnyards in the immediate vicinity of
the point where the water is taken out. Just what percentage of
pollution may be eliminated in this way it is impossible to determine,
but it is not too much to say that no brook or pond should be used for a
water-supply of a house unless _every known pollution_ of an organic
nature has been removed. Under the most favorable circumstances there
will be enough accidental contamination to make the water at times
dangerous, and no added risks ought to be assumed.

In looking over a watershed the possibility of sewage entering the
stream is, of all pollutions, the most to be avoided. To adequately
investigate the quality of a stream, the inspector must satisfy himself
as to the point of discharge of the sewer of every house on the
watershed, and this must be done personally, without apparently
reflecting on the statements of the owner of the house. If any such
points of discharge are found, the sewage should be either diverted into
some other watershed, or spread out over the ground away from the
stream, or purified by some artificial treatment before discharge, or
else the creek water cannot be used.

The next point to be noted in the source of the water-supply is the
presence and location of privies. These nuisances should be as far back
from the banks of the streams as possible to eliminate all danger since
the surface of the ground always slopes toward some stream, and
pollution may be carried for considerable distances over or through the
soil. Water-tight boxes can be provided so that no possible pollution of
the surface-wash can occur, and if periodically the contents of these
boxes be hauled away and buried, the privy loses its dangerous
character. The city of Syracuse has installed on the watershed of
Skaneateles Lake a most admirable system of collection of privy wastes,
and the lake water is tho