MUSIIROOMS 415 
it is not feasible or practicable for every grower to pro- 
duce his own spawn. Those who are interested in this 
phase of the industry should study Duggar’s “Mushroom 
Growing,” Chapter VIII. It is gratifying, however, that 
there are reliable American firms from whom pure cul- 
ture spawn may be obtained at reasonable prices, so that 
no one need take chances in planting ordinary commercial 
spawn, whether it is made in the United States or in 
foreign countries. Growers will do well to make a 
thorough investigation of the sources of good spawn 
before making purchases. Different varieties may be 
obtained and tested just as gardeners test different sorts 
of tomatoes or lettuce. 
The pure cultures are generally sold in the usual 
commercial brick forms, as seen in Fig. 152. The bricks 
Fig. 152.—Drying bricks of mushroom spawn. 
measure about 5% by 8% by 1% inches. They pack 
readily for shipment and are easily broken for spawning 
the beds. It is exceedingly important to use fresh spawn. 
That which is a year old seldom gives good results. 
Duggar recommends that growers use spawn not more 
than six or eight months old, and they will do well to 
