In selecting manure for mushroom work only that which is recognized as of the highest quality should be taken. It is the general experience that considerable bedding straw should be present with the manure, and if good straw it is not likely to contain too much, but even a small quantity of "weeds" is a nuisance. The straw of the various grains seems to possess distinct advantages over that of other grasses, perhaps on account of a certain resistance to complete fermentation, or decay, yielding a highly porous substratum which maintains an excellent physical condition in the beds.