at hard water is
due, although this has not been substantiated. No information is to-day
available by which the fitness of a soil for securing sanitary
conditions of building can be determined.

_Cancer and soil conditions._

In the case of cancer, however, while no final conclusions can be drawn,
there is some definite indication that the soil conditions have
connection with the occurrence and continued appearance of cancer. It is
known that this dread disease is abnormally prevalent in certain
districts of the world where topography and climate are fairly alike.
For example, the entire region between the Danube and the Alps from
Vienna westward and between the Jura and Alps to Geneva furnishes the
highest mortality from cancer in all Europe. The subsoil is clay with a
thin covering of surface soil, the hillsides draining on to level
valleys with meandering watercourses that frequently inundate and
supersaturate the already moist soil.

This condition seems to prevail wherever cancer is abnormally prevalent.
In England, in northwestern France, and in Spain the topography
described in every case accompanies a high death-rate from cancer. It is
of great interest to find that in New York State the two districts that
are conspicuously affected by this disease have the same topography. The
Unadilla Valley and some parts of the Allegheny Valley are noted for
their cancer houses, and in both localities we find the same kinds of
hillsides and water-soaked valleys as in Germany and France. It has also
been noted that the older geological formations are free from the
disease and that an occasional inundation does not seem to be a factor.
Altogether there seems to be some ground for assuming a connection
between cancer and soil conditions, at any rate until scientists have
determined the real cause of the disease in those localities where it is
now so markedly prevalent.

_Topography._

The soil, however, with its mineral characteristics, does indirectly
affect the health of the householder because different kinds of rock
form themselves naturally into different surface formations, some
healthy and some unhealthy. For example, localities where granite rock
abounds and comes near the surface are usually healthy because the
surface slope is great enough to carry off all drainage water rapidly.
The air therefore is dry and not influenced by the immediate vicinity of
swamps. The drinking water is soft, and malarial breeding pla