1910] REED—TRANSPIRATION AND GROWTH OF WHEAT IOI 
In attempting an explanation for these differences, attention may 
be directed first to the fact that the plants in my experiments were 
grown for longer periods of time in the acid solutions than those of 
the previous investigators, and the possibility exists that accelerated 
transpiration of these plants was temporary and would eventually 
have given place to a retardation. The plants upon which my obser- 
vations were made had developed almost from germination in the 
solutions to be tested, since they were transferred to the solutions 
when the longest roots were 2-3°™ long. 
The greatest reason for the apparent difference in results is believed 
to be due to the fact that the previous writers have taken no account 
of the correlated growth in measuring transpiration. Transpiration 
is probably a function of growth, and as such cannot be separated 
from it. It seems more correct, therefore, to estimate the effect of a 
treatment in terms of the transpiration per unit of green weight, or, 
since in my experiments the green weight was at the beginning of the 
experiment almost mil, to estimate the effect of the treatment in terms 
of the transpiration per unit increase in green weight. 
THE ACTION OF ALKALIES 
This problem was also studied by the earlier investigators in 
manner similar to that employed for studying the action of acids, 
which, as previously stated, is open to certain objections. The . 
results of my experiments, which record the amount of transpiration 
per unit of green growth, disagree with those of the writers quoted. 
My experiments on this point were conducted upon wheat plants grow- 
ing in water cultures, prepared by the methods previously described. 
The hydroxids of potassium and of sodium were present in these 
cultures in concentration of n/10o; this involved the addition of 39 
Parts per million of K in the form of KOH, and 23 parts of Na as 
aOH, amounts approximating those employed in the other experi- 
ments. / 
Table IV presents the average result of two experiments in which 
KOH and NaOH were added to extract of Hagerstown loam, a 
Sample which was known to “respond” to potash fertilizers being 
used, 
Unfortunately, the number of my observations is small, and it 
