Nov. 26,1917 
Hydrocyanic-Acid Gas as a Soil Fumigant 
427 
a dilution of 0.5871 gm. of sodium cyanid per liter (equivalent to 0.1761 
per cent of hydrocyanic-acid gas over the solution), while in the aqueous 
solutions all were killed, up to and including a dilution of 1.1742 gm. of 
sodium cyanid per liter (equivalent to 0.352 per cent of hydrocyanic-acid 
gas over the solution). Stimulation was shown in both series at about 
the same dilution. In the columns of Table IV showing plants in aqueous 
solutions of hydrocyanic-acid gas and soil watered with hydrocyanic-acid 
gas solutions, a very close similarity will be seen in the effect on the plant, 
whether the roots are entirely immersed or the plant is grown in a soil 
moistened with hydrocyanic-acid gas solutions. 
Table IV .—Summary of effect of hydrocyanic-acid gas on plants 
Sodium cyanid 
Soil watered with 
solutions of 
Roots in aqueous 
solutions of 
Cuttings in aqueous 
solutions of 
Leaves exposed to 
hydrocyanic-add 
nroc 
per liter. 
hydrocyanic-acid 
hydrocyanic-add 
hydrocyanic-acid 
gas. 
gas. 
gas. 
Gm. 
18. 788 
9 - 394 
Dead . 
.do . 
Dead . 
Dead . 
Dead. 
] 
'50 per cent 
4. 697 
.do. 
.do. 
shriveled. 
| Do. 
50 per cent 
dead. 
J 
2. 3485 
.do. 
.do. 
Shriveled. 
Do. 
[Tips growing. .. 
1.1742 
.do . 
.do . 
< Stems shriv- 
Do. 
'50 per cent 
25 per cent 
[ eled. 
20 per cent 
* 5 $ 7 i 
shriveled. 
alive. 
alive. 
1 Do. 
50 per cent 
75 per cent 
80 per cent 
dead. 
dead. 
dead. 
25 per cent 
50 per cent 
Tips growing. .. 
*2935 
normal. 
' 75 per cent 
normal. 
50 per cent 
Stems wilty. ... 
•Partially dried. 
dead. 
dead. 
50 per cent 
88 per cent 
75 per cent 
. 1467 
normal. 
normal. 
normal. 
Do. 
50 per cent 
12 per cent 
25 per cent 
dead. 
dead. 
dead. 
[94 per cent 
Tender leaves 
*0733 
Normal . 
< normal. 
Normal . 
dead. 
16 per cent dead . 
Normal . 
Dead. 
. 03 66 
.0183 
. . 4 do. 
.do. 
Acceleration. 
Do. 
.....do. 
.do. 
.do. 
20 per cent 
. 0091 
.do. 
acceleration. 
80 per cent 
•....do. 
Normal. 
normal. 
90 per cent 
.0045 
.do. 
normal. 
•.... do. 
Do. 
10 per cent 
acceleration. 
5 per cent ac¬ 
.0022$ 
.do. 
celeration. 
■.... do. 
Do. 
95 per cent 
normal. 
Water. 
.....do. 
Normal. 
.do. 
Do. 
1 
