aces, says Pettenkofer, was that in the healthful
stables the ground water was five to six feet below the surface, while
in the unhealthful ones it was only two and a half feet from the
surface. A system of drainage by which the ground water was brought to
the same level under both stables made them equally healthful. The
writer cannot help but feel that some other factor was involved, and
while he has no doubt that excessive dampness in stables or cellars is
undesirable, he does not believe that such dampness can be directly the
cause of fevers of any sort.

It is not desirable, however, to live over a wet cellar nor to maintain
a house in a constant condition of dampness, partly on account of its
bad effect on the house and partly because such dampness may, by
reducing the vitality of the household, become a predisposing factor in
disease.

_Drainage._

From whatever source dampness may come, it can be guarded against by
giving to the surface of the ground in the vicinity of the house, on all
sides, sufficient slope away from the walls so that there will be no
tendency for water to accumulate against the cellar walls. On the top of
a hill this is very easy to do, and the natural surface grade takes care
of the surface water without difficulty. On a sidehill or in a valley
artificial grading has to be resorted to, except on one side.

[Illustration: FIG. 3.--A grading that turns water away from the house.]

Too much emphasis cannot be laid on the necessity for grading the ground
surface away from the house. In some cases it may be sufficient to dig a
broad shallow trench protected from wash by sods (Fig. 3). In other
cases it may be desirable to pave the ditch with cobble stones or to
build a cement gutter. In constructing such a surface drain, proper
allowance must be made for the accumulation of snow and the resulting
amount of water in the spring, so that the distance in which the ground
slopes away from the house ought to be, if possible, at least ten feet,
so that there can be no standing water to penetrate the house walls. The
slope necessary to carry surface water away need not be great. A fall of
one foot in one hundred will be ample, even on grassy areas, and if the
surface is that of a macadam road or the gutters of a drive, this grade
may be cut in two. A slope of more than one foot in one hundred is
permissible up to a maximum of seven or eight feet per hundred, more
than this being aesthetically objec