546 
Journal of Agricultural Research 
Vol. vn. No. 12 
recorded for cabbage plants may be due to the fact that the leaves were 
sprayed only on the upper surfaces, and that at best only a very imperfect 
film was obtained. 
Table VIII .—Average ratio values for periods after treatment , relative to the corre¬ 
sponding ratio values for the standardization periods taken as unity, being a summary 
of the average data from Tables III, IV, V, VI, and VII 
Plant. 
Transpiration 
(ratio A':B). 
Water loss per 
gram of dry 
substance 
(ratio A'G':BG). 
Water loss per 
gram of green 
substance 
(ratio A'D':BD). 
Cabbage... 
I.03 
I.03 
I.03 
Eggplant.... 
I. II 
I. 12 
I. 12 
Pepper. 
I. 29 
I. 29 
I. 29 
Tomato. 
I. 08 
I.09 
1.07 
Sav hpfin . . 
I. 64 
It is further to be noted that with each species employed in these 
experiments the three ratios, each derived from a single set of the three 
kinds of measurements here dealt with—transpiration, water loss per 
gram of green substance, and water loss per gram of dry substance-— 
are in very close agreement. The greatest variation in the values of 
the three ratios occurred with tomato plants. The values of the ratios 
in question are 1.08,1.09, and 1.07 for transpiration quantities, water loss 
per gram of green substance, and water loss per gram of dry substance, 
respectively. The influence of Bordeaux mixture in bringing about 
increased rates of transpiration varies with the different species of plants, 
as is indicated by the variation in the ratio values for the different species. 
This has already been observed in the experiments with abscised leaves. 
A comparison of the results obtained from abscised leaves with those 
obtained from potted plants shows very clearly that the influence of 
Bordeaux mixture in bringing about increased rates of transpiration 
is much more pronounced when the spray is applied to abscised leaves 
than when applied to the leaves of potted plants. Thus, the ratio values 
representing the highest and lowest average increased rates of water 
loss from abscised leaves, due to an application of Bordeaux mixture, 
are 3.71 and 1.73, respectively, relative to the corresponding ratio 
values for the standardization periods taken as unity. The ratio values 
representing the highest and lowest average increased rates of transpi¬ 
ration from potted plants, following an application of Bordeaux mixture, 
are 1.64 and 1.02, respectively, relative to the corresponding ratio values 
for the time period before spraying. 
SUMMARY 
The results of the experiments presented above substantiate the 
general principle already established by Duggar and Cooley (6, 7) that 
the rates of transpiration from abscised leaves and also from the leaves 
