[Vor. 5 
172 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
early fall rendered this impossible. Leaves of the castor 
bean, which in our earlier work had been found favorable for 
studies of this kind, were procurable in large number, but 
under the conditions maintaining in the greenhouse they 
proved subject to great fluctuations and to severe wilting. In 
many cases the leaves wilted in test chambers where the at- 
mosphere was kept fairly moist, and the indications were that 
the cause might lie in the movement of viscous materials into 
the conducting channels. Nevertheless, one completed series 
was maintained under satisfactory conditions and the results 
are shown in table 1x. The leaf stems were inserted through 
one mouth of a Wolff bottle into a weak Crone solution, move- 
ment of the leaves with the rotation of the table, when this 
occurred, being prevented by means of a lump of plasticene. 
In this case, however, weighings were made on a trip balance, 
weighing accurately to .1 gram. 
From the data presented it will be seen that the sprayed 
plants exhibit an increase in the transpiration loss through- 
out all intervals of the experiment. In this case the increased 
water loss in the night interval is no more pronounced than 
during any other interval. The results here are in complete 
accord with those previously reported from this laboratory, 
and it would seem reasonable to anticipate that some general 
explanation may be advanced to account for the striking dif- 
ferences noted in these experiments as between excised leaves, 
on the one hand, and potted plants, such as the potato, tomato, 
and tobacco, on the other. 
DISCUSSION AND SUMMARY 
The data presented in this paper offer a mass of additional 
proof to establish the point that a film of Bordeaux mixture or 
of certain other materials of similar physical characteristics 
influence, often to a marked degree, the rate of water loss 
from the plant. Although the work accomplished does not 
yet include as many types of plants as might be wished, nor 
are the conditions of the environment so completely measured 
or eontrolled that the relation of this inereased water loss 
to environmental faetors may be clearly defined, yet that both 
