22 
JNT. C. Experiment Station 
It early became evident that cotton seed in an air dry condition cannot 
endure the high temperatures used by Atanasoff and Johnson 2 and others 
in the treatment of cereal seeds. Air dry cotton seeds completely lost 
their power to germinate when heated at temperatures of 90 and 100° C. for 
periods as short as 15 minutes. The application of dry heat at 80° C. for 
one hour completely inhibited germination of seed of the 1919 crop and 
greatly reduced and prolonged germination of the 1921 and 1922 crops. Dry 
heat at 70° C. was endured for much longer periods without total loss of 
viability but even that temperature produced marked injury to certain lots 
of seed. In Experiment 5, in which three lots of seed of the 1919 crop were 
heated at 70° C. for 6, 24 and 72 hours, the treated seed yielded germination 
percentages of 70, 40 and 60 in comparison with 90 for the untreated check 
seeds. Other tests with seed of this crop yielded similar results. In a test 
(Exp. 6) with seeds of the 1923 crop whose water content had diminished 
to 8.3 per cent as a result of storage under laboratory conditions, two lots 
which had been heated for 24 and 48 hours gave respectively 98 and 90 per 
cent of germination in comparison with 92 per cent for the untreated seeds. 
In Experiment 7, two lots of seeds of the 1923 crop taken from the same 
container as those used in Experiment 6 were stored over water in a closed 
dish until they had absorbed sufficient vapor from the moist air to raise 
their water content to 11 and 14.3 per cent; then each lot was heated for 
24 hours at 70°. A marked reduction in the percentage of germination re¬ 
sulted from the treatment. Seventy-eight and 80 per cent of the seed of the 
two treated lots and 97 per cent of the untreated lot germinated. In Ex¬ 
periment 8, three lots of seed of the 1924 crop were used. These seed 
originally came from the same bag but differed in water content as a 
result of different storage conditions for several days previous to the time 
of the heat treatment. Lot 1 was stored in an open dish in the labora¬ 
tory, and underwent a marked reduction of its water content; lot 2 was 
taken from the center of a two bushel bag stored in the laboratory and had 
lost less water because of the bulk of the seed around it, and lot 3 was 
kept in a glass stoppered specimen jar. The three lots contained water 
amounting respectively to 7.98, 10.65 and 13.22 per cent of their wet 
weight, and after being heated at 70° for 24 hours, gave germination per¬ 
centages of 73, 60 and 49 in comparison with 71, 72, and 77 for correspond¬ 
ing unheated lots. Seventy degrees appears to be slightly above the 
maximum temperature which cotton seed containing an amount of mois¬ 
ture normal to ordinary storage conditions can safely endure for any 
considerable period of time. 
A number of tests were made to determine the amount of anthracnose 
which might develop on seedlings growing from seeds which had been 
heated at 70°. Table VII shows the results of some of these tests. 
