




Igor] EFFECT OF HYDROCYANIC ACID GAS 255 
slight growth after breaking through the seed coats. Leaving 
out of account the advance that the seeds made toward germina- 
tion while they were in the water and before placing them in the 
gas, it appears that their sensitiveness increased with the length 
of time that they were allowed to soak. This is to be expected 
since hydrocyanic acid gas has a strong affinity for moisture and 
is readily absorbed by water. 
Seeds soaked for a definite time in water, placed re a given time 
in hydrocyanic acid gas, and then removed to a gas free atmosphere.— 
When it was observed that the seeds which had been soaked and 
then placed in hydrocyanic acid gas germinated more slowly than 
under normal conditions, it was apparent that the seeds were 
being held in a dormant state for a longer or shorter time 
depending upon the length of time the seeds were soaked, upon 
the strength of gas used, and upon the length of time that the 
seeds were allowed to remain in the gas. In order to get more 
definite information in regard to this point, experiments were 
undertaken whose results are recorded in tables VI and VII. 
TABLE VL 
Germination of seeds and subsequent growth of seedlings after soaking in water, 
then placing for a definite time in hydrocyanic acid gas, and then removing to a 
gas free atmosphere ; temperature 18° C 




ount : Time of Time required Percentage | Subsequent growth 
KCN per cubic feta of exposure , ot | of 
‘oot aking to gas germination germination seedlings 
O:000) 2. 24 hours ° 24 hours 100 normal 
GGGs tS ry EARS: 168 hours | already germ. go slow 
GOR ek 24° Aes Ses 168 hours 50 very slow 
aa kag ae et ia 168“ Ce 20 sale started 
O.C60 oni, ea eee 16s." no germination ° 
0.120 24" POS os es 0 





As shown in table III, seeds that have been soaked for 
twenty-four hours and then left for seven.days or 168 hours in 
an atmosphere containing gas from 0.003 of KCN per cubic 
feet were able at the end of that time to germinate without 
removing from the gas, while seeds subjected to a stronger 
charge of gas were unable to germinate in the gas. Hence the 
