
258 BOTANICAL GAZETTE [ APRIL 
undertaken in order to determine whether the hydrocyanic 
acid gas that retarded germination after the seeds were removed 
from the atmosphere of the gas remained in the moisture that 
adhered to the seeds, whether the gas was primarily absorbed 
by the seeds, or whether retardation was simply an after effect 
of the gas upon the seeds. 
TABLE VIII. 
Seeds soaked, placed for a definite time in hydrocyanic acid gas, then washed and 
placed in an atmosphere free from hydrocyanic acid gas ; temperature throughout 
experiment about 18° C. 




KEN’ od Time of exposure Subsequent ie grain - Percentage of ae 
cubic foot soaking to gas treatment germination seedlings 
0.000 . 24 hours (a) Borsa 24 hours 100 normal 
O400°: Ba 6 hours | washed ora ay 100 i 
Gil00 ss P 24ge (aie notwashed| 96 “ 50 3{ nat. size 
EGO 2a pn washed i440 100 normal 
D.250 -; 1 Sg oe not washed| no germ. fe) wane 
Oso Sea ies ade washed 168 hours 60 ¥ nat. size 
0.250 . | 24 “ 24035 washed ye eile 10 slight 
C250 48h eae ADS washed no germ. fc) 







It is apparent that more or less of the hydrocyanic acid gas 
remains in the film of water that adheres to and surrounds the 
seeds after they are removed from the gas, since they germinate 
much more readily after washing. It should be noted that the 
washing did not consist in soaking the seeds but simply rinsing 
them under the hydrant. If the seeds were not washed they 
were unable to germinate after six hours in the gas from 0.250 
of KCN per cubic foot, whereas the seeds were able to germi- 
nate after eighteen hours in the gas, providing they were washed 
immediately after removal. If they were exposed to the same 
charge of gas, viz., 0.250" of KCN per cubic feet for twenty- 
four hours or more, they were unable to germinate even when 
they were thoroughly washed after removing from the gas. It 
would seem from the experiments that more or less of this pol- 
sonous gas remains in the moisture that surrounds the seeds, 
and that the gas clings to the damp surface of exposed seeds. 
If the gas is not removed by washing it seems to have a strong 
