Treatment of Cotton Seed 
47 
dry condition are quickly destroyed by a temperature of 100° C., they 
may endure this temperature for 26 hours without loss of viability if 
they are first thoroughly dried and then heated in a vacuum or in an 
inert atmosphere as nitrogen. 
EXPERIMENTAL 
A number of experiments were performed in order to determine the 
temperature and period of time most suitable and practical for drying 
cotton seed in order to condition them to withstand the higher temperatures 
required for killing the anthracnose fungus. In certain of these experi¬ 
ments the extent of dehydration was measured by determining the pro¬ 
portion of water lost during the treatment. In all these tests, precaution 
was taken to have the separate lots reasonably uniform by first selecting 
and thoroughly mixing enough seeds for the entire experiment then me¬ 
chanically dividing the heap into the number of lots required. Each lot 
was dried separately in one electric oven and heated in another, so it 
was not necessary to change the adjustment of the oven thermostat during 
the course of an experiment. 
Table I gives the data of Experiment 1 in which 5 lots of seed were dried 
at temperatures of 40, 45, 50, 55 and 60° C. for 24 hours and afterward 
heated at 90° for 18 hours. The percentage of germination was recorded at 
the end of 2, 3, 4, 5, 6, 9 and 14 days. 
TABLE I 
Effect of Desiccation at Temperatures of 40, 45, 50, 55, and 60° C. for 24 Hours 
as a Means of Preparing Cotton Seed to Withstand a Temperature 
of 90° C. for 18 Hours. 50 Seeds in Each Lot. Crop of 1922. 
Exp. No. 
Lot No. 
Preliminary Drying 
Subsequent Heating 
Per Cent of Germination 
Temp. 
Deg. C. 
Time 
Hours 
Temp. 
Deg. C. 
Time 
Hours 
Days in Germinator 
2 
3 
4 
5 
6 
9 
14 
1 
1 
40 
24 
90 
18 
0 
4 
16 
22 
28 
28 
36 
2 
45 
24 
90 
18 
0 
28 
60 
62 
62 
62 
62 
3 
50 
24 
90 
18 
4 
74 
92 
96 
96 
96 
4 
55 
24 
90 
18 
2 
76 
96 
96 
96 
96 
5 
60 
24 
90 
18 
2 
66 
96 
— 
96 
98 
98 
Lots 1 and 2, which had been dried at 40 and 45° C. respectively showed 
marked diminution in both the rate and final percentage of germination. 
Temperatures of 40 and 45° C., when applied for periods not longer than 
24 hours, do not condition cotton seed to endure without injury to germi¬ 
nation the temperature of 90° C. for 18 hours. For this purpose it is 
necessary to use a temperature of 50° C. or above. In all lots which were 
dried at 50° C. or above, germination was prompt and entirely satisfactory 
in amount. 
In Experiment 2, the results of which are set forth in Table II, the tem¬ 
perature of drying was kept the same for all lots but the period of heating 
was varied. Four lots were dried at 50° C. for 12, 18, 24 and 36 hours, and 
subsequently heated at 90° C. for 24 hours. The percentage of germination 
