62 
JNT. C. Experiment Station 
viable in only 20 per cent of the seeds of the untreated check. When lot 3 
was removed, 16 per cent of the 50 seeds put to germinate or 27 per cent of 
the 32 seedlings which grew became diseased, while only 2 per cent of the 
untreated check developed anthracnose. Thus, it appears that in 26 per 
cent (46%-20%) of the desiccated seeds which germinated in lot 2, the 
vitality of the anthracnose fungus was prolonged to 17 Vz months by storage 
in the desiccator, whereas, under ordinary conditions of laboratory storage, 
the fungus in these seeds would have perished by this time. Likewise, as 
indicated by lot 3, the anthracnose fungus was preserved in a viable condition 
to 21V 2 months in 25 per cent (27%-2%) of the treated seeds. 
p 
The results of Experiment 2 are not in complete harmony with those of 
the other tests, although the seed were from the same bag as those used in Ex¬ 
periment 1. In tests made at the end of 60 and 116 days fewer seedlings 
became diseased in treated than in untreated seed. This anomalous outcome 
is probably dependent on the fact of the more advanced age of the seed when 
put to desiccate. In Experiment 1, the seed were put to desiccate on July 
21, 1920, when they were 9 Mj months old, while in Experiment 2, they were 
put in the desiccator on December IS, 1920, at which time they were 14^ 
months old. When untreated seed were tested on July 1, 1920, 66 per cent 
of the seedlings became diseased; on Sept. 17, 1920, 34 per cent and on 
January 18, 1921, just one month after Experiment 2 was begun, only 6 
per cent of the seedlings in one lot and none in another became diseased. 
Thus it is seen that when Experiment 1 was started a large percentage of 
the seeds were carrying the anthracnose fungus in a viable condition while 
by the time Experiment 2 was begun the seed had passed through the sum¬ 
mer months and the anthracnose fungus in most of the seeds had died as 
a result of ageing. Until two weeks before Experiment 1 was started, these 
seed were stored in an out-building; after this time they were kept in 
the laboratory. During the period of storage in the laboratory before Ex¬ 
periment 2 was begun the water content of the seeds decreased from ap¬ 
proximately 11 per cent to approximately 9 per cent. In Experiments 3 
and 4, it is shown that the desiccating agents removed all or nearly all the 
free water from the seeds, and it is assumed that this is likewise the case 
in Experiments 1 and 2. 
From the experiments described above, it is seen that the vitality of the 
seed-borne elements of the cotton anthracnose fungus is prolonged and not 
shortened by storing diseased seed at room temperature over desiccating 
chemicals such as con H 2 S0 4 and dry CaO,. This increase in the length of 
life of the fungus appears to be conditioned by a pronounced loss of water 
from the seeds and is probably due primarily to a decided decrease of the 
already low respiratory activity of the fungus and seed. When diseased seed 
are treated with dry heat, it is not the desiccation which destroys the life 
of the anthracnose fungus, but the direct, presumably coagulating effect of the 
heat on the fungus protoplasm, which appears to be less resistant to heat 
than the protoplasm of the seed itself. The reduction of the water content 
of seeds which are being treated is sought only as a means of conditioning 
the seed to withstand the ordinarily injurious effects of the high temperature 
necessary to kill the invading fungus. 
