P. blakesleeanus was grown in a basal medium of distilled water, minerals, dextrose, and asparagine plus purified agar and thiamine in various proportions and combinations. The mycelium was harvested with hot or cold water using aluminum pans and Gooch crucibles. With the liquid medium, the dry wt. of mycelium washed with cold water was higher than that washed with hot water, probably because hot water dissolved substances from the mycelium. Higher dry wt. of mycelium grown on agar and washed with cold water may be due to this action of hot water and to incomplete removal of agar with cold water. Reduced growth was correlated with increased amt. of agar.