' MUSHROOM GROWING 



is due in large part, at least, to the elimina- 

 tion of certain "biological" factors and 

 enemies. The presence, by accident, of 

 contaminating organisms in the culture 

 causes an immediate suppression of the 

 mushroom mycelium, and this shows in a 

 measure what happens in nature. The 

 sporophores of the mushroom have been 

 produced in Mason jar cultures in our lab- 

 oratory at a temperature constantly at or 

 above 70°, and in pot cultures under prac- 

 tically sterile conditions at a temperature 

 constantly between 60° and 70° F. We 

 have not had an opportunity of testing on a 

 large scale the possibility of growing mush- 

 rooms during warmer weather under essen- 

 tially pure conditions, that is, in manure 

 sterilized on a large scale, as the soils of 

 greenhouses are frequently sterilized. This 

 might be done merely to throw light on the 

 causes of injury at high temperature, as I 

 doubt if the general sterilization of compost 

 in mushroom work is a remote practical 

 possibility. All kinds of sanitary precau- 



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