1913] GODDARD—SOIL FUNGI 201 
germ-proof cotton stopper. The tube leading from the last divided 
into three, one entering each culture flask and dipping below the 
liquid, Each tube before entering the culture flask contained a 
bulb 2 cm. in diameter, which was also filled with cotton loosely 
packed. An exit tube passed out of each flask. The three from 

Fic, 18.—Apparatus for investigations IV (A) and III (B) 
each set united into one, and these common tubes from each set 
united to form one tube which was connected to a filter pump. 
By the operation of this pump a slow stream of air was kept bub- 
bling through all the cultures of both sets during the entire culture 
period. By means of clamps this stream was kept quite uniform 
