1914] 
DUGGAR AND COOLEY—FILMS AND TRANSPIRATION 355 
More stress should, however, be laid upon the data from the 
first period. Тһе green weights of the plants discarded at the 
close of the first period were taken immediately, while those 
plants used in the second period could not be weighed until the 
close of that interval. This small interval of time, however, 
could eause no material change in the weights. In the accom- 
panying table there are given in grams the average water loss 
per plant, the average green weight per plant, and the water 
loss per gram of green matter. 
From the data exhibited it is obvious that with potted 
potatoes, as with castor bean leaves and potted tomatoes in our 
earlier experiments, there is a marked acceleration of transpira- 
tion induced by spraying with Bordeaux mixture, as also with 
some other films. Of the several films employed, lime sulfur 
alone yields an average water loss comparable with that of 
unsprayed plants. Of all lots showing increased transpiration 
those treated with weak Bordeaux and lime wash were in some 
respects most satisfactory, inasmuch as the plants used, like 
those in the control, were, in general, in very good condition 
throughout the period of the experiment. On the other hand, 
those treated with the stronger Bordeaux, the Bordeaux and 
iampblack, and the lime and lampblack gave, towards the close 
of the periods, evidences of the injurious effects of the increased 
transpiration (apparently) upon the vitality of the plants. 
Тһеве statements may not seem to be in entire aecord with 
the figures presented, for during the second period of the ex- 
periment, for example, the transpiration quantity is relatively 
greatest in the case of those plants sprayed with weak Bordeaux 
mixture. Nevertheless, our observations enabled us to predict 
that certain lots, especially numbers 1 and 6, would give in the 
second period, particularly, transpiration values less than 
might be anticipated. The smaller quantities in the lots re- 
ferred to, as contrasted with the weak Bordeaux, are to be 
explained, in fact, as a direct result of incipient wilting and 
slight injury, brought about by the higher transpiration capacity 
induced under conditions already accentuating transpiration. 
It is believed, in the first place, that the experiments here 
reported confirm our earlier conclusion, namely, that a film of 
Bordeaux mixture facilitates water loss; but, in the second place, 
