[Vor. 3 
70 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
at 22-24^C., this being the lowest constant temperature that 
could be procured in the room. The incubator outside was 
set at 16°C., but on account of the wide variation in atmos- 
pherie temperatures it was not possible to keep it constant 
at this point. At times the temperatures reached as high 
as 21°C., and at other times as low as 10°C. In spite of this 
variation no yellows occurred in the incubator which was out- 
side until some days after all the plants in the warmer incu- 
bator had been attacked. Twenty pots of soil from the experi- 
mental field at Racine were placed in the warm incubator and 
twenty similar pots were placed in the cool incubator. The 
pots were put in the incubators on November 5, 1914, and in 
four days the plants in one pot showed wilting. The plants 
were sixteen days old when they were submitted to the trial. 
Previous to this time they had been growing in the green- 
house which was kept at 12-14°C. On November 11 yellowing 
was apparent in all the pots except the controls, some of the 
plants also showing wilting. In the outside incubator but 
two plants showed a slight yellowing and there was no wilt- 
ing. Damping off due to Rhizoctonia was rather extensive 
in some of the pots because of the relatively high humidity 
eonditions. Counts were taken on November 14 of the plants 
in the warm ineubator, and seedlings from both ineubators 
were plated on potato hard agar. The results were as fol- 
lows: 
At 22-24" C. F. conglutinans was isolated from plants from 
every pot of the infeeted soil, while none could be isolated 
from the plants in the normal greenhouse soil. When the 
plants from eight pots of infected soil, growing at 10-16°C., 
were plated F. conglutinans was isolated from but one; the 
fungus was not isolated from the eontrols. In the twenty pots 
at 22-247 C. there was a total of 104 plants, seven of which re- 
mained healthy, while in the incubator at 10-162 C. there was 
a total of eighty-eight plants, only one of which showed the 
disease even after they had been left until December 1 in the 
incubator. Table хп summarizes the results obtained on this 
temperature relation. 
