724 
Journal of Agricultural Research 
Vol. V, No. 16 
placed in battery jars. The toothed tops of the cylinders allowed a 
circulation of air. For tests with light, the cultures were ordinarily 
placed in a battery jar and covered with filter paper or cloth to protect 
them from dust. As a further safeguard from error, however, a similar 
container was made, but with celluloid substituted for black paper. 
The result with corn broth, after three weeks, is given in Table V. 
Table; V.— Effect of light: Test with corn broth in light-tight box 
Conditions. 
Pycnidia. 
Growth. 
Light in battery jar. 
+ + + 
+ + 
Fair. 
Fair. 
Strong. 
Light in celluloid chamber. 
Dark in black-paper chamber. 
From this experimentation it is evident that light is a determining 
factor for pycnidium formation in this organism, irrespective of the type 
of nourishment, and that the action of light is distinct from effects which 
might be attributed to faulty aeration in the darkened cultures. The 
slight depression of pycnidia formation in the slightly darkened celluloid 
chamber is significant. Growth is increased in the dark. 
Cultures on com broth, in *both light and dark, were subjected to a 
variety of air conditions. Stoppered flasks were fitted with two glass 
tubes, one of which extended to the surface of the culture, the other 
merely through the cork. As indicated in Table VI, some were connected 
with the water pump and filtered air which had bubbled through water 
was gently drawn through. As a check, some flasks were left with no 
additional circulation, while some were plugged with cotton. 
Table; VI.— Effect of air circulation: Test with corn broth in stoppered flasks 
[Time, i month*] 
Conditions. 
Pycnidia. 
Growth. 
Attached to aspirator: 
Light. 
++++ 
++ 
++++ 
-\— h 
+++ 
++ 
+++ 
Dark. 
Air only through small tubes: 
Light. 
++ 
Dark. 
Flasks plugged with cotton: 
Light. 
++++ 
Dark. 
1 The experiment was continued a second month with no change in relative values. 
This experiment eliminates any possibility that the effect attributed 
to light may have come from faulty aeration or deficient transpiration. 
The experiment further has significance from the point of view of aeration. 
