46 
C. Experiment Station 
to heat was found to bear an inverse relation to initial water content at the 
time of heating. Temperatures approaching the maximum for the seed of a 
given water content caused more or less pronounced retardation of 
germination. 
Burgess 6 in 1919 published data showing the percentage of germination 
of certain agricultural seeds which had been subjected in an air dry 
condition to high temperatures. Wheat and rye were killed by an ex¬ 
posure of one hour to 248° F. but gave respectively 55 per cent and 78 
per cent germination when heated for 3 hours at 230° F. Ninety-eight per cent 
of oats and 2 per cent of cowpea seeds germinated after 5 hours of heating at 
194° F. Soybeans gave perfect germination after exposure for one hour at 
194° F., and soybeans, garden beans and cowpea seeds gave respectively 100 
per cent, 92 per cent and 78 per cent germination after subjection for 3 hours 
to heat at 176° F. 
In 1920, Saillard 47 subjected sugarbeet seed of three grades designated 
“very good,” “good” and “poor,” which gave before treatment, 98, 87 and 36 
per cent germination respectively, to dry heat at temperatures ranging from 
60 to 105° C. After treatment at 80° C. the respective percentages of 
germination for the three lots was 97, 86, and 9 per cent; after treatment 
at 90° C., 95, 75 and 2; and after treatment at 100° C., 80, 46 and 0. 
Of the “very good” seeds 3 per cent survived the treatment at 105° C. 
In 1922, Gain 22 published the results of experiments with sunflower 
seeds. He found that by carefully drying and heating the seeds for 
suitable periods of time at temperatures which were raised by successive 
steps, many of the seeds could be prepared to endure temperatures as high 
as 150° C. After similar treatment, seeds of a number of other plants 
were found to endure temperatures of 110 to 155° C. without complete loss 
of power to germinate. Similar experiments by Sigalas and Marneffe 51 
confirm the work of Gain. 
In addition to the workers whose papers are reviewed in the above 
paragraphs, others as Groves, 26 Crocker and Groves, 10 Goodspeed, 25 Harring¬ 
ton and Crocker, 31 Honing, 35 Hausdorfer, 32 Schneider-Orelli, 49 Neuberger, 45 
Just, 39 and Schubert 50 have published from time to time the results of 
studies on the effect of desiccation and the application of heat on the 
viability, longevity and germination of seeds. In general, these workers 
have found that air dry seeds are much more resistant to dry than to 
moist heat and that preliminary desiccation over chemicals or at low 
temperatures greatly increases the ability of seeds to withstand exposure 
to high temperatures. 
Few workers have published any data showing the effect of dry heat 
on cotton seed. The publications of Story, 5;! , 54 Gough 24 and Lipscomb and 
Corley 43 have been cited in an earlier part of this paper. Gough, using a 
machine designed for treatment of cotton seed to kill the pink boll worm 
found that, when the seed remained in the machine for nine minutes and 
the temperature of the seed did not exceed 51° C., very little reduction of 
germination resulted, but injury was marked at 61° C. and very severe 
at 72° C. Lipscomb and Corley found that ,while cotton seeds in an air 
