TREATMENTS OF SEED WHEAT FOR LOOSE SMUT 3 
for both wheat and barley, stating also that it has been found entirely 
feasible to vary the temperature at will between 105° and 120° F. 
(40.55° to 48.88° C), provided the duration of treatment is varied 
accordingly within a range of one and a half to six hours. No specific 
recommendations are made regarding the duration of treatment within 
the limits of temperature defined, except the one noted above. Since 
it is desirable to make the treatments as short as possible, the shortest 
duration of treatment (one and one-half hours) and a temperature 
(48° C.) close to the highest recommended by Humphrey and Potter 
(6) were used as a starting point in the experiments with single-bath 
treatments, descriptions of which follow. 
For a number of years previous to the beginning of the investiga- 
tions reported here the Office of Cereal Investigations conducted 
experiments on the single-bath hot-water treatments for the control 
of the loose smuts in wheat and barley in cooperation with the agricul- 
tural experiment stations of Minnesota and Wisconsin. A. A. Potter 
had charge of the work at Washington, while the work in Minnesota 
was conducted by E. C. Stakman and that in Wisconsin was under 
the supervision of A. G. Johnson. The results of these earlier investi- 
gations are unpublished, but they have been made available for 
study by the writer, who is grateful to these workers and the officials 
of the experiment stations concerned for the use of the data. The 
writer is further indebted to Mr. Potter for suggestions regarding 
certain temperatures that should be given special consideration. 
METHODS AND MATERIALS 
Unless otherwise noted in the following experiments dealing with 
hot water, the seed was treated in cheesecloth bags with ample room 
to allow for the swelling of the grain. The 60-gallon tank used for 
treatment was equipped with two motor-driven propellers, which 
kept the water thoroughly agitated and the temperature uniformly 
distributed. Thermostatically controlled electric heaters were em- 
ployed to maintain the desired temperatures, which were held in all 
cases with a plus or minus variation not in excess of 0.2° C. All of 
the thermometers employed had been standardized by the United 
States Bureau of Standards. 
The single-bath treatments were applied without presoaking. The 
modified treatment was applied by presoaking the grain for four to 
five hours in cold water, followed by a momentary tempering dip in 
water at about 49° C. and a 10-minute immersion in water at 54 C. 
Immediately after treatment the seed was spread in a thin layer to 
cool. In order to reduce its moisture content to about that of the 
untreated seed, it was left to dry for five days or more at room tem- 
perature. Germination tests in the greenhouse soil were made by 
sowing 100 seeds per flat in flats 1 foot wide by 2 feet long. Uniform 
spacing and deptn of sowing were insured by pressing into the soil 
one hundred 1-inch pegs inserted equidistantly in a board. The 
kernels were dropped into the holes made by these pegs and then 
covered. 
