536 Journal of Agricultural Research vd. vn, no. X3 
Prom the brief summary in Table II it will be observed that the lowest 
ratio value for any period after treatment is 1.37 times the ratio value for 
the corresponding standardization period, while the highest ratio value 
is 3.72 times the ratio value for the corresponding standardization period. 
The average value of the ratios for periods after spraying is 1.99 times 
the average ratio for the standardization periods. Expressed in another 
way, the leaves sprayed with Bordeaux mixture showed an increase in 
the rates of water loss, relative to their respective controls in each case, 
varying from 37 per cent for the lowest increase to 272 per cent for the 
highest. The average rate of water loss by transpiration of the species 
here employed shows an increase of 99 per cent over the average rate for 
the standardization period. The degree of this accelerating influence of 
Bordeaux mixture on the rates of transpiration varies considerably with 
the different species of leaves, as is indicated by this wide range of varia¬ 
tion in the ratio values for the different leaves. 
The leaves employed in these experiments were allowed to remain in 
the places occupied during the experiments for some time after* the 
experiments had been terminated and were kept under observation to 
determine whether the sprayed or the unsprayed leaves should first show 
signs of wilting. It was observed that in every instance the sprayed 
leaves showed signs of wilting at some period preceding the time at which 
the unsprayed leaves of the same species began to wilt. This is only what 
would be expected in view of the fact that the average rate of water loss 
from the sprayed leaves is nearly double that from the unsprayed leaves 
during the experimental time period. 
EXPERIMENTS WITH POTTED PLANTS 
Experimental methods. —In the experiments with potted plants the 
method of procedure was similar to that followed in the experiments with 
abscised leaves. The plants employed consisted of tomato (Lycopersicon 
esculentum Mill.), cabbage (Brassica oleracea L.), pepper (Capsicum 
annuum L.), egg plant (Solanum melongena L.), and soy bean (Glycine 
hispida M.). These plants, excepting the soy beans, were grown in beds 
of soil in the greenhouse until they had attained a size suitable for experi¬ 
mentation of this character. They were then transplanted to earthen¬ 
ware pots glazed inside and outside and having a capacity of approxi¬ 
mately 1.5 liters. In order to prevent evaporation from the surface of 
the soil, melted wax prepared according to the Briggs and Shantz formula 
was poured over the surface of the soil in each pot, thus making a perfect 
seal. 
Water was automatically supplied to the roots of the plants by means 
of the autoirrigator. This instrument has been described by Livingston 
(12) and later by Hawkins (11). It consists of a porous clay cup closed 
by a rubber stopper through which extend two glass tubes. One of these 
tubes is bent into the form of an inverted U having one arm considerably 
