THE CONTROL OF CABBAGE BLACK-LEG. 7 
It will not be necessary to consider in detail the data obtained when 
the seeds were exposed at 90° and 95° C, as listed in Table I. Lot 
No. 3-18 again proved to be the most resistant, while the remaining 
lots, as a rule, received marked injury at these temperatures. Parallel 
treatments of highly infected seeds showed that the fungus had been 
killed within 18 hours at 95° C. and within 96 hours at 85° C. Both 
of these treatments might, therefore, be of practical use with lot No. 
3-18, but would be very injurious to the other lots. 
A quantity of No. 3-18 seed was dried first at 37° to 50° C. for five 
days, then at 73° C. for three days, by which means the moisture con- 
tent was reduced to 1.31 per cent. The seed was then placed in an 
incubator running at 100° C. The results (Table I) showed that in 
spite of the reduced water content the ability to resist this high tem- 
perature was not increased. Agar-plate tests with badly infected 
seed similarly treated were not made. However, a sample dried at 
40° to 50° C. for 19 days and then at 85° C. for one day, the moisture 
content being reduced to 1.44 per cent of the dry weight, yielded 
almost as much disease as untreated seed in seed-bed trials. This fact 
indicates that prolonged drying at moderate temperatures does not 
materially affect the fungus. 
It is evident from the foregoing data that cabbage seed is not uni- 
formly resistant to desiccation at high temperatures. Moreover, the 
fungus within or beneath the testa is so resistant to this treatment 
that complete eradication of it from infected seed by baking is im- 
possible without considerable injury to the seed. These facts, to- 
gether with the difficulty of applying this treatment on a large scale, 
give doubtful value to this method for commercial use with cabbage 
seed. 
FORMALDEHYDE SOLUTION. 
In the trials with formaldehyde solution use was made of formalde- 
hyde, standard strength of approximately 40 per cent, diluted with 
distilled water. Aside from one treatment with a 1 : 256 solution for 
37 minutes, which was approximately the same as the formula used on 
a commercial scale in 1918, the stronger concentration (1:128) was 
used throughout the experiments with formaldehyde. Unless other- 
wise noted the solutions were used at room temperature, approxi- 
mately 20° C. Certain of the lots were rinsed in clean water; others 
were not rinsed. All were spread out in thin layers after treatment 
and allowed to dry under laboratory conditions. As will be seen from 
the results given in Table II, the latter treatment always produced 
greater injury than resulted in the case of corresponding rinsed lots. 
The deleterious effect of formaldehyde upon cabbage seed becomes 
evident both as reduction in percentage of seed germination and as 
injury to the seedlings. The data in Table II show a progressive 
decline in the percentage of germination of commercial seeds with the 
