CULTIVATION OF MUSHROOMS. 



259 



hand, is that which is propagated artificially by the special prepara- 

 tion of the substratum or material in which the mycelium is to grow. 

 This material is inoculated either with a piece of natural spawn, or 

 with pieces of previously manufactured spawn. It is put upon the 

 market in two different forms ; the brick spawn, and the flake spawn. 

 The latter is sometimes known as the French spawn, while the 

 former, being largely manufactured in England, is sometimes spoken 

 of as the English spawn. 



Brick spawn. The brick spawn is so called because the material in 

 which the mycelium is present is in the form of bricks. These 

 bricks are about 5 by 8 inches by \y 2 inches in thickness, and weigh 

 about 134" pounds each when dried. The proportions of different 



FIGURE 233. Brick spawn. Three " bricks," one marked to show into how many 



pieces one brick may be broken. 



kinds of material used in the manufacture of brick spawn probably 

 vary with different manufacturers, since there is a difference in the 

 size and texture of bricks from different sources. One method of 

 making the brick spawn is as follows : Equal parts of horse dung, 

 and cow dung, and loam soil are thoroughly mixed together to a con- 

 sistency of mortar. This is pressed into the form of bricks and 

 stood on edge to dry. When partly dry, a piece of spawn about an 

 inch in diameter is pressed into one side of each brick. The bricks 

 are then stood up again until thoroughly dried. They are then piled 

 upon a layer of fresh horse manure about 8 inches deep, the pile of 

 bricks being about 3 feet high. This pile is then covered over 

 loosely with fresh horse manure, a sufficient amount to produce, 



