MUSHROOM. 337 



the bed. A convenient width is four feet, and the length 

 may be as great as desired. First spread a thin layer of 

 the compost, pounding it down firmly with a brick or 

 mallet, layer after layer, until it reaches a depth of eight 

 inches. Be careful that the thickness is just about 

 eight inches, as, if more, it would heat too violently, 

 and if less, it would not heat enough. Into this bed 

 plunge a thermometer. In two or three days the bed 

 will heat, so that the thermometer will rise to one hun- 

 dred degrees or over. As soon as the temperature de- 

 clines to ninety degrees, take a sharp stick and make 



Fig. 138. MtTSHBOOMS. 



holes an inch or so in diameter all over the bed, at about 

 a foot apart and six inches deep. Into these holes drop 

 two or three pieces of "spawn," and cover up the holes 

 again with the compost of which the bed is made, and 

 beat it slightly again, so that the bed will present the 

 same level surface as before the spawn was put in. Let 

 the bed remain in this condition for ten or twelve days, 

 by which time the spawn will have run all through it. 

 Now spread evenly over the surface of the bed about two 

 inches of fresh loam, press it down moderately with the 



