11 
Treatment of Cotto^ Seed 
In test 1, 6 per cent of the treated as compared with 66 per cent of 
the untreated seed produced diseased seedlings. Likewise, in tests 2 and 
o, a marked reduction in number of diseased seedlings resulted from the 
treatment. However, in none of the four tests did delinting with sul¬ 
phuric acid completely suppress the disease. With the 10 minute treat¬ 
ment a small amount of fuzz still persisted at the large end of the seed 
and this may have prevented the complete destruction of such infective 
material as may have lodged in it. However, with the 30 minute treat¬ 
ment, the seed coats were much corroded and the lint was so completely 
removed that it seemed impossible for any spores or surface borne 
material to survive. Crawford 17 supplemented the usual treatment with 
sulphuric acid by subjecting delinted, washed and dried seed to a second 
charring with sulphuric acid and a subsequent treatment with a 1-1000 
solution of mercuric chloride. He reports that, when such seed were 
germinated on sterile blotting paper, cultures of Glomerella gossypii 
Diplodia gossypii, Cephalothecium sp., Alternaria sp. and Fusarium vasin- 
fectum were obtained from them. These tests make obvious the conclu¬ 
sion that while seedling infection may be greatly diminished it cannot 
be completely eliminated by delinting. 
C. Hot water. In 1910, Duggar and Cauthen 19 testing the efficiency of 
various seed treatments found that the amount of seed borne infection 
in the case of cotton anthracnose could be greatly lessened by immersing 
diseased seeds for 22 minutes in water of a temperature of 150° P. Of the 
bolls which grew on these treated plants, 2.4 per cent became diseased 
compared with 9.9 per cent on plants from untreated seed. The marked 
reduction in percentage of diseased bolls apparently resulting from this 
treatment aroused the hope that the complete elimination of seed-borne 
infection might be accomplished. In 1914, Barre and Aull 12 published a 
preliminary report of their work with the hot water treatment. They 
found that seeds could be kept in water at 70° C. for 15 minutes without 
injury to germination and, when so treated, diseased seed germinated free 
from disease, while disease appeared on 22 per cent of the seedlings from 
the untreated seed. However, in field tests of seed which had been 
treated at 75° C. for 15 minutes made during this and subsequent 
years, 5 , 6 , 12 a small amount of disease developed on the plants grown from 
treated seed. This amounted to much less than one per cent of the bolls 
on plants from treated seed, whereas 15 per cent of the bolls from un¬ 
treated seed became diseased. 
The method is encumbered by certain difficulties of operation. It appears 
that a temperature of less than 70° C. for fifteen minutes is too low to 
destroy the seed-borne infection, while a temperature of more than 75° C. 
for 15 minutes causes unfavorable reduction in germination of the seed 
treated 19 , 12 Barre 6 has stated that some varieties of cotton are killed at 
72° C. while others will tolerate 76° C. These close temperature limits 
for the killing of the seed and of the fungus make it difficult in practice 
to maintain the water at a proper temperature when seed are treated in 
quantity. This operation is troublesome since it involves a suitable place for 
drying the seed 1 and considerable time and labor. Moreover, after cotton 
seed have been treated by the hot water method, they must be dried 
