The natural spawn, as indicated above, is employed for a variety of purposes. It is used for inoculating the bricks in the manufacture of brick spawn. It is used for propagating once or twice in the mushroom beds, for the purpose of multiplying it, either in the manufacture of brick spawn, or for flake spawn, which is planted directly in the beds to be used for the crop. In some places in America it is collected on a large scale and relied on as the chief source of spawn for planting beds. In such cases the natural or virgin spawn is used directly and is of the first and most vigorous generation. It is believed by growers who employ it in this way that the results in the quality and quantity of the crop exceed those produced from the market spawn. But even these growers would not always depend on the natural spawn, for the reason, that collecting it under these conditions, the quantity is certain to vary from year to year. This is due probably to varying conditions of the season and also to the varying conditions which bring about the chance inoculation, or the accumulation of the material in the yard for a sufficient amount of time to provide the mycelium. It would be interesting, and it might also prove to be profitable to growers, if some attempt were made to grow natural spawn under conditions which would perhaps more certainly produce a supply. This might be attempted in several different ways. Stall-fed horses might be fed a ripe mushroom every day or two. Or from the cap of ripe mushrooms the spores might be caught, then mixed with oats and fed to the horse. Again, the manure piles might be inoculated by spores caught from a number of mushrooms. Manure might also be collected during the summer months from the highways and aside from the probable natural inoculation which this material would probably have from the spores blown from the meadow and pasture mushrooms, additional inoculation might be made. The manure obtained in this way could be piled under sheds, packed down thoroughly, and not allowed to heat above 100° F. These piles could then be left for several months, care being used that the material should have the proper moisture content, not too dry nor too wet. This is given only as a suggestion and it is hoped that some practical grower will test it upon a small scale. In all cases the temperature should be kept low during the fermentation of these piles, else the spawn will be killed. One of the methods of obtaining natural spawn recommended by Cuthill ("Treatise on the Cultivation of the Mushroom") is to collect horse droppings all along the highways during the summer, mixing it with some road sand and piling it in a dry shed. Here it is packed down firmly to prevent the heat rising too high. A "trial" stick is kept in the pile. When this is pulled out, if it is so hot as to "burn the hand," the heat is too great and would kill the spawn. In several months an abundance of the spawn is generated here.