For commercial purposes the English method of making the spawn into bricks has some advantages over the French "flake" process. Its compact and uniform shape makes the brick more convenient for storage and general handling, and greatly facilitates its transportation to long distances. Brick spawn is made in the following manner: Clean horse droppings, cow manure, loam, and road sweepings are beaten up in a mortar-like consistency and then formed into bricks, moulds being used, slightly differing in shape with different makers, but usually thinner and wider than common building bricks. The following proportions are given: (1) Horse droppings the chief part; one-fourth cow dung; remainder loam. (2) Fresh horse droppings mixed with short litter for the greater part; cow dung, one third; and the rest mould or loam. (3) Horse dung, cow dung, and loam, in equal parts. When about half dry, depressions are made in the bricks, sometimes in the centre, and sometimes in each corner, and small pieces of good spawn are placed in these depressions, and plastered over with the material of the brick. The cakes are then laid out to dry, standing on their edges, and when nearly dry are piled in pairs with the spawn-larded surfaces face to face. The bricks are then stacked away, and covered with sweet fermenting litter, sufficiently to cause a heat of 60 F. It should not be over 70 F. One spawn manufacturer says that the most rapid and successful growth of the mycelium is attained when the temperature is from 63 F. to 67 F. The bricks are examined frequently during the process, and when the mycelium of the old spawn has permeated the whole mass like a fine white mould, the bricks are taken out and dried in a well-ventilated dark place. They are then placed in a cool, dark storehouse, where they are not subject to dampness and where the temperature is about 50 F., not over 65 or below 35 F. Slight ventilation is necessary, but not enough to make the bricks dust-dry. Keeping the spawn dry merely suspends its growth; as soon as it is again submitted to favorable conditions of moisture and heat, its pristine activity returns. Dampness, combined with heat, stimulates the growth of mycelium; frost also destroys the vitality of the spawn. It is evident, therefore, that these conditions should not exist in the store-room. One manufacturer advocates piling the bricks, after spawning, on a clay floor, packing closely four bricks deep, and covering them with sifted loam. By this method it is claimed that danger of "fire fang" will be avoided, as the bricks will be kept at a perfectly uniform temperature of about 60 or 66, which causes the spawn to run quickly and uniformly. In from four to six weeks they are ready to take out and dry for use or storage.