1914] 
DUGGAR AND COOLEY—FILMS AND TRANSPIRATION 11 
to a more rapid water elimination after spraying. Potted 
potato plants from which the shoots were cut withstood the 
fungicide satisfactorily. 
Leaves of the large elephant’s ear (Caladium sp.) proved 
unsatisfactory on account of the excessive ‘‘bloom,” which 
interfered with the proper application of the spray. Canna 
leaves were similarly unfavorable, and leaves of the calla lily 
wilt soon after abscision. 
It has been stated above that the leaves of the castor bean 
proved most satisfactory in the potometer work. The experi- 
ments with these leaves were carried out in the open, except 
as otherwise noted, during the early fall. The plants were 
arranged for standardization and for subsequent observation 
at distances of about ten feet apart on an exposed lawn uni- 
formly sodded. No readings were made until the leaves had 
become adjusted to the conditions. Observations were made at 
frequent intervals when the water loss was rapid, in order to 
maintain the water column at a fairly uniform level, so that 
many of the data given in the tables which follow represent 
summations of several successive readings. Three series of 
potometer experiments were made, each series embracing six 
leaves, but in one series, accidents to some of the leaves, and 
the necessity of substituting new ones after the experiment 
began, resulted in such a shortening of the standardization 
intervals that it was thought necessary to discard the results, 
although they were in the same direction as the others obtained. 
The data are presented in full in the tables and all available 
data are used in computing the relations given. The relations 
may be more conveniently expressed if we first divide the 
leaves into classes, designated by letters, as follows: 
А-, three leaves (i. e., the transpiration quantities of these) 
in the standardization interval before spraying. 
A+, the same three leaves as in А--, but for апу interval 
after spraying. 
B, three control leaves (unsprayed throughout) during the 
standardization interval. 
В’, the control leaves as in B, after standardization. 
The ratio a =Q is to be compared with the ratio 2+0. 
