doned mines, where no expense is necessary in the
erection of houses. The temperature throughout the year is favorable for
the growth of the mushrooms without artificial heating. It is possible,
also, to grow them on a large scale during the warm summer months when
it is impossible to grow them under the present conditions in heating
house structures, and also when the market price of the mushrooms is
very high, and can be controlled largely by the grower. For this reason,
if it were possible to construct a house with some practical system of
cooling the air through the summer, and prevent the drip, the
cultivation in houses would probably be more profitable.

[Illustration: FIGURE 223.--View in Akron "tunnel," N. Y. Mushroom Co.
Beds beginning to bear. Copyright.]

For the past few years the writer has been giving some attention to the
different methods of the cultivation of mushrooms in America, and in
response to the growing interest for information concerning the
artificial cultivation of these plants, it has seemed well to add this
chapter on the cultivation of mushrooms to the second edition of the
present work. The cultivation as practiced in America exists under a
great variety of conditions. All of these conditions have not been
thoroughly investigated, and yet a sufficient number of them have been
rather carefully studied to warrant the preparation of this chapter. The
illustrations which have been made from time to time, by flash light, of
the cave culture of mushrooms in America, as well as of the house
culture, will serve to illustrate graphically some of the stages in the
progress of the work. For present purposes we will consider, first, the
conditions under which the cultivation is carried on, followed by a
discussion of the principles involved in the selection and preparation
of the material, the selection and planting of the spawn, as well as the
harvesting of the crop.

THE CAVE CULTURE OF MUSHROOMS IN AMERICA.

[Illustration: FIGURE 224.--View in Akron "tunnel," N. Y. Mushroom Co.
Beds beginning to bear. Copyright.]

This has been practiced for a number of years in different parts of the
Eastern United States, but perhaps only a small portion of the available
caves or tunnels are at present used for this purpose. These
subterranean mushroom farms are usually established in some abandoned
mine where, the rock having been removed, the space is readily adapted
to this purpose, if portions of the