530 
Journal of Agricultural Research 
Vol. VII, No. 
While the last-named authors have definitely established the fact that 
surface films with certain specific characteristics have an accelerating 
influence on rates of transpiration when applied to the leaves of castor 
bean, tomato, and potato plants, the problem here involved seemed to 
be of sufficient importance to warrant further investigation in a different 
locality and under different conditions. 
It was the purpose of the experiments here reported to determine the 
influence of Bordeaux mixture on the rates of transpiration of abscised 
leaves of several species, as well as to determine the effect of this spray 
material upon the rates of water loss from a variety of potted plants. 
The experiments were carried out in the greenhouse of the Department 
of Plant Pathology of the New Jersey Agricultural Experiment Station. 
EXPERIMENTS WITH ABSCISED LEAVES 
Experimental methods. —Abscised leaves of radish (Raphanus 
saiivus L.), bean (Phaseolus vulgaris L.)> Swiss chard {Beta cycla L.)> 
Hibiscus cardinalis, Clerodendrum balfouri , Caladium sp., Datura mete - 
loides , and castor bean (Ricinus communis L.) were used. The leaves, 
together with portions of the stems, were severed from the plants and 
the cut ends immediately placed in water. They were then taken to the 
greenhouse room, where the experiments were carried out. The leaves 
were now cut off under water and the petioles were inserted into 
Erlenmeyer flasks having a capacity of 180 c. c.; the flasks were nearly 
filled with water. A layer of cotton was then placed tightly around the 
leaf petiole just at the surface of the water; this served to hold the leaf 
in place. The flasks were sealed by pouring melted wax over the cotton 
around the leaf petioles. This wax was prepared according to the for¬ 
mula of Briggs and Shantz (3) and consisted of a mixture of about 80 
per cent of paraffin and 20 per cent of petrolatum. The mixture had a 
melting point of about 45 0 C. By pouring a layer of this wax about 1 cm. 
thick on the layer of cotton around the leaf petioles the leaves were held 
firmly in place. To permit the entrance of air into the flasks as water 
was removed by transpiration from the leaf a small hole was made in 
the wax with a pin. 
In testing the effect of Bordeaux mixture on the rates of transpiration 
of abscised leaves, six leaves of each species were employed. These were 
chosen from larger groups of leaves which had been mounted as above 
described and allowed to stand for some time in order to become adjusted 
to the new conditions. Leaves of the different species used were chosen 
with special reference to equality of surface exposed and also with 
reference to similarity of general appearance. The six leaves chosen 
were divided into two groups of three each. For facility in comparison 
and for ease of reference in discussion, one of these groups will be desig¬ 
nated “series A” for periods before treatment and “series A'” for periods 
after treatment; the other group, remaining untreated throughout the 
experiment, will be designated “series B.” 
