260 STUDIES OF AMERICAN FUNGI. 



when heating, a temperature of about 100 F. They are left in this 

 condition until the mycelium or "fiber" has thoroughly permeated 

 the bricks. The spawn is now completed, and the bricks are allowed 

 to dry. In this condition they are put upon the market. The bricks 

 made with a very high percentage of soil often have the appearance 

 of dried soil, with a slight admixture of vegetable matter. 



Brick spawn from other sources presents a very different texture 

 and contains probably a much larger percentage of horse manure, 

 or, at least, a much smaller percentage of soil. The appearance of 

 the brick is not that of soil with a slight admixture of vegetable 

 materials, but has much the appearance of a dried and compressed 

 mixture of horse dung and cow dung, with an abundance of the 

 "fiber" or mycelium, "the greyish moldy, or thready matter," 

 which constitutes the vital part of the spawn. In the selection of 

 spawn this is an important item, that is, the presence of an abund- 

 ance of " fiber " or mycelium. It can be seen on the surface, usually 

 showing an abundance of these whitish threads or sheets, or a 

 distinct moldy appearance is presented. On breaking the brick the 

 great abundance of the "fiber' or whitish mycelium is seen all 

 through it. This indicates that the brick possesses a high percentage 

 of the " fiber," an important part of the spawn. 



One not accustomed to the quality of spawn can therefore judge 

 to a certain extent by the appearance of the bricks as to the quality, 

 at least they can judge as to the presence of an abundance or a 

 scanty quantity of the "fiber." Since the spawn remains in good 

 condition for several years, there is usually no danger in the use of 

 spawn which may be one or two years old. But it does deteriorate 

 to some extent with age, and young spawn is therefore to be pre- 

 ferred to old spawn, provided the other desirable qualities are equal. 

 Those who attempt to cultivate mushrooms, and depend on com- 

 mercial or manufactured spawn, should see to it that the spawn 

 purchased possesses these desirable qualities of texture, and the 

 presence of an abundance of the mycelium. That which appears 

 devoid of an abundance of mycelium should be rejected, and good 

 spawn should be called for. There is no more reason why a grower 

 should accept a worthless spawn from his seedsman than that he 

 should accept "addled" eggs from his grocer. In this business, 

 that is, the manufacture and sale of spawn, poor material is apt to 

 be thrown on the market just as in the case of seeds, poor material 

 may find its way upon the market. Sometimes this occurs through un- 

 scrupulous dealers, at other times through their ignorance, or through 

 their failure to know the quality of the product they are handling. 



