PLATE 2 
A.—Sitka spruce inoculated with an unidentified mold, commonly found on this 
species in nature. The mold mycelium, stained by the '‘Berlin blue” method, ap¬ 
peared as clear bright blue threads. Section cut near surface. 
BSitka spruce attacked by Monilia sitophila. Note development of large mycelia 
threads. Section stained with gold chlorid, applied after a treatment of 5 Hours with 
sodium acid sulphite. Section was in the gold solution 20 hours. 
C. —Aspen attacked by Aspergillus niger. Infection confined chiefly to the pores. 
This section was soaked 6 hours in borax (an unnecessarily long time), and left in gold 
chlorid solution 17K hours. 
D. —Maple attacked by a wood-destroying fungus. Dilute silver nitrate used very 
successfully as a stain. The wood appeared yellow and the fungus threads dark 
brown. There was no trace of precipitate in this case. 
