28o 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9. 
C, and D. These experiments seem to indicate that alcohol does not pro- 
duce an initial increase in the rate of production of carbon dioxide. 
After experimentation the seeds were allowed to grow on wet filter 
paper in a moist chamber in sunlight. If they had been exposed for ten 
minutes to /[M alcohol, there was no subsequent growth. After an expo- 
sure of five minutes there was slight growth of the root tip and considerable 
(though retarded) growth of the stem. After an exposure of three min- 
utes the retardation of growth was very slight. 
It is difficult to make any comparisons between growth and the pro- 
duction of carbon dioxide for the reason that the susceptibility of the differ- 
ent parts of the seedlings varies. The root tip is most sensitive, so that a 
short exposure may influence its growth considerably, but it represents 
only a small portion of the seedling, so that its injury may not make much 
difference in the production of carbon dioxide if the remaining, less suscep- 
tible portion is left unaffected. A great decrease in the production of 
carbon dioxide takes place only when the entire seedling is affected to such 
an extent that there is no subsequent growth. 
When the seedlings are exposed to solutions of alcohol for about 
five minutes, formation of acids other than carbonic takes place. This may 
be detected by the following method. Twenty seedlings were put into a 
glass-stoppered Pyrex tube with 3 cc. of tap water (containing the same 
amount of indicator as in the standard tube) for twenty minutes; 2 cc. 
of this liquid were then put into the indicator tube, and air free from carbon 
dioxide was passed into the tube just as in the previous experiments. The 
time required to bring the liquid to pH 7.6 by thus driving carbon dioxide 
out of the liquid was about three minutes. The same seedlings were now 
placed in a glass-stoppered tube containing a 4Af solution of alcohol, washed 
for one half minute in running water and placed in 3 cc. of tap water for 
twenty minutes. 2 cc. of this liquid were then placed in the indicator tube, 
and the air free from carbon dioxide was passed through it to drive out the 
carbon dioxide. After three minutes' exposure of the seedlings to 4M 
alcohol, the time recorded was about the same as in the control. This indi- 
cates that there is no acid other than carbonic in the liquid.^ But when 
the seedlings had been exposed for five minutes to the same concentration 
of alcohol the change was very much slower; in many cases the change did 
not take place within ten minutes. After ten minutes there was no change 
within twenty minutes. This proves that acids, other than carbonic, 
must be present in the liquid. The slowness of the change back to pH 
7.6 cannot be due to excess of carbon dioxide, since the previous experi- 
ments show that less carbon dioxide is produced in /\.M alcohol. 
The question arises whether the presence of such acids is due to the 
extraction by alcohol of acids already present before the experiment was 
2 When other volatile acids are absorbed by water, it is difficult to drive the acid out 
of the water by a current of air and bring the water back to neutrality. 
