GRAINS AND OTHER SEEDS 179 
The gas thus absorbed has a marked influence upon 
the germination of the seeds and upon the subsequent 
growth of the seedlings. In these experiments it was 
found that some of the seeds were able to resist for 
more than three hours the influence of the gas from 
0.25 gramme of potassium cyanide per cubic foot, al- 
though after three hours 50 per cent. of the seeds were 
unable to germinate and the other half were held in 
check for forty-eight hours beyond the usual time of 
germination. However, the seeds that did germinate 
produced seedlings that grew at the normal rate. If 
the grains or seeds are dry, the influence of the gas is 
far less marked than if they are moist, and the drier 
they are, the less they are influenced by the gas. 
It would seem, therefore, that the gas exerts its in- 
fluence through the medium of the moisture contained 
in the seeds and in the seedlings. Even in older plants 
it is the more succulent parts that are most readily af- 
fected by the gas. The seed-coats serve more or less 
as a protection for the inner seed parts, and as soon as 
the seedlings escape from the seed-coats they are more 
seriously affected by the gas, and if the charge is suf- 
ficiently strong the seedlings refuse to grow almost as 
soon as they leave the seed-coats. Dry seeds are suf- 
ficiently resistant to the influence of hydrocyanic acid 
gas to be treated for several weeks with an atmosphere 
saturated with the gas without destroying their vital- 
ity. It would be impossible, however, to preserve 
even dry seeds indefinitely in any strength of the gas, 
since it eventually penetrates the dry seeds and im- 
pairs and finally destroys the vitality of the seeds. If 
the seeds are damp they are much more susceptible to 
