In nearly every country place, and in numerous suburban ones, in fact, in most places where horses are kept, opportunities of finding this spawn occur. Its white, filamentous, and downy threads have the odour of mushrooms, and the spawn is, therefore, very easily recognised. It should be generally known that it need not be used when found, but may be dried, and kept for use in a dry place for years, and has been known to keep as long as fourteen years. It must not be supposed that it is only the hard bricks described further on that keep thus. The French spawn is in much looser and lighter material than that in which we usually find _mycelium_ in a natural state, and it keeps quite as long as ours. To preserve spawn found in a natural state, nothing more is required than to take up carefully the parts of the manure in which it is found, not breaking them up more than may be necessary, and placing both large and small pieces loosely in rough shallow hampers. These should be placed in some dry airy loft or shed till thoroughly dry, and afterwards kept in some perfectly dry place, packed in rough boxes till wanted for use. [Illustration: Fig. 11. Brick mushroom-spawn.] But inasmuch as in this country, at present, but little mushroom-spawn is required in any one place, the rule is to obtain artificial spawn in the form of hard bricks. This spawn is made from horse-droppings and some cowdung and road scrapings beaten up into a mortar-like consistency in a shed, and then formed into bricks, slightly differing in shape with different makers, but usually thinner and wider than common building bricks. Various recipes are given for mixing the materials for the bricks, and among them the following are about the best:--1. Horse-droppings the chief part, cowdung a fourth, and the remainder loam. 2. Fresh horse-droppings mixed with short litter the greater part, cowdung one third, and the rest mould or loam. 3. Horsedung, cowdung, and loam in equal parts. These bricks are placed in some dry, airy place, and when half dry, a little bit of spawn about as big as a hazel nut, is placed in the centre of each; or sometimes, when the bricks are as wide as long, a particle is put near each corner, just inserted below the surface, and plastered over with the composition of which the bricks are made. When the bricks are nearly dry, they are placed on a hotbed about a foot thick, in a shed or dry place. On this the bricks are piled, or placed rather openly and loosely, and covered over with litter, so that the heat may circulate equably amongst them. The temperature should not rise more than a degree or two above 60 degrees; if it does, it may easily be modified by reducing or removing the covering of litter. The makers frequently examine the bricks during the process, and when the spawn has been found to spread throughout a brick like a fine white mould, it is removed, and allowed to dry for future use in a dark, dry place.