66 
!N\ C. Experiment Station 
EFFECT OF STORING INFECTED COTTON SEED IN HYDROGEN AND IN 
CARBON DIOXIDE 
A number of experiments have been made to determine the effect of an 
atmosphere of hydrogen and of carbon dioxide on the vitality of diseased 
cotton seed and on the logevity of the spores and mycelium of the 
anthracnose fungus carried by such seed. As in previous experiments, the 
seeds used were selected in order to remove all seeds which were, so far 
as could be judged from external appearances, incapable of germination. 
These selected seeds were stored in lots of several hundred in 750 cc. 
bottles provided with 2-holed rubber stoppers. The stoppers were vaselined, 
pressed tightly into the bottles and tied down with strong cord. The gases 
used were made to displace the air in the bottles containing the seeds by 
passing into them by way of 2-holed stoppers quantities of the desired 
gases equal to several times the volume of the bottles. When the air in 
the bottles had been displaced, the holes in the stoppers were closed by 
pushing tightly fitting vaselined glass rods into them. The bottles were 
were then kept on a laboratory shelf at room temperature. The bottles were 
recharged with appropriate gases each time samples of seeds were removed 
for germination tests. 
The hydrogen used was produced by the action of zinc and sulphuric 
acid in a Kipp generator and was passed through wash bottles contain¬ 
ing H 2 S0 4 KOH solutions. In Experiment 1, the hydrogen was dried 
by passing it through a tube filled with Ca0 2 . The carbon dioxide used was 
produced by the interaction of H 2 S0 4 and air slacked lime in a flask pro¬ 
vided with suitable outlets and was used without further purification. 
In Experiments 1 and 2 the untreated seeds used for checks were kept in 
TABLE YII 
Per Cent of Anthracnose and Germination in Cotton Seeds Stored in Carbon 
Dioxide and in Hydrogen. 50 Seeds in Each Lot. 
Exp. 
No. 
Lot 
No. 
Gas 
Used 
Per Cent 
Germination 
Per Cent 
Anthracnose 
Age of Seed 
Year 
Har¬ 
vested 
Treated 
Seed 
Untreated 
Seed 
Treated 
Seed 
Untreated 
Seed 
When 
Stored 
When 
Tested 
1 
1 
h 2 
98 
100 
6 
60 
3 x /i mo. 
10 mo. 
1921 
2 
h 2 
90 
100 
8 
32 
3U 2 
ioy 2 
1921 
3 
h 2 
88 
94 
2 
20 
3J4 
u y 2 
1921 
2 
1 
CO 2 
96 
100a 
32 
60a 
3J4 
10 mo. 
1921 
2 
CO 2 
96 
100a 
26 
32a 
sy 2 
ioy 2 
1921 
3 
CO 2 
92 
94a 
2 
20a 
3 H 
17 H 
1921 
3 
1 
h 2 
94 
98 
58 
90 
6 mo. 
lOy mo. 
1922 
2 
H 2 
100 
96 
36 
68 
6 
13 
1922 
4 
1 
CO 2 
92 
96b 
50 
68b 
6 
13 mo. 
1922 
5 
1 
h 2 
92 
98 
28 
28 
5 mo. 
6 mo. 
1923 
2 
ID 
98 
98 
26 
26 
5 mo. 
9 mo. 
1923 
6 
1 
CO 2 
96 
98c 
28 
28c 
5 
6 mo. 
1923 
2 
CO 2 
94 
98c 
40 
26c 
5 
9 
1923 
aUntreated seeds same as for Exp. 1. 
bUntreated seeds same as for Exp. 3. 
cUntreated seeds same as for Exp. 5. 
