CurTis: SOME OBSERVATIONS ON TRANSPIRATION 369 
36. Six days later the same plant, having been returned to the 
green house, gave from 10.10 a. m. these readings : gain 0, 6, 2, loss 
4,7,4, 8. Temp. 22 to 23.5, Hygrm. 32 to 30. The changes in 
the temperature and humidity were not corollated with the fluctu- 
ations. The gain in weight may be due to a precipitation similar 
to that noted by Volken in certain plants. 
I was interested to make some further investigations upon the 
relations between cuticular and intracellular transpiration. The 
results will be found in Table V._ The stems and petioles of plants 
from which the immature leaves had been removed a week previ- 
ous were carefully sealed with wax mixture and the transpiration 
rate determined in the dark for three hours. Then the under sur- 
face of the leaves were rubbed with the wax so as to thoroughly 
plug the stomata and then coated with a further coat of the wax. 
The figures indicate that the stomata were closed. This wax mix- 
ture, referred to above, seems to me to offer a much better sealing 
mixture that the commonly employed shellac preparations which 
may react upon the living cells. 
V. CurtTicutar AND INTRACELLULAR TRANSPIRATION 
9 A.M. Io II 12,30P.M. 1.30 2.30 3.30 4.30 5-39 
FICUS ELASTICA, 70 76 107 4 7 9 12 10 10 
Temperature, 18.8 19.5 ee 
Hygrometer, 50 52 48 
FIcUs ELASTICA, 163 175 6 Pee 10 12 12 
Temperature, 22 23 
flygrometer, 48 45 
FICUS ELASTICA, 37 38 bth Be go fo 6 8 
Temperature, 19.5 Ig 20 
Flygrometer, ApS 46 43 
In the cases under consideration, where the diffusion owing to 
the nature of the leaf must be at a minimum, the results would 
appear to warrant the conclusion that the stomata are sufficiently 
Open to permit diastomic transpiration during the night. The 
work of Blackman in demonstrating the slow diffusion of CO, 
through the cuticular membrane of leaves, likewise that of Mor- 
ren in reference to the absorption of SO, are suggestive of a similar 
action for vapor gas. It would also be difficult to understand how 
Tespiration may in all cases be effected at night by diffusion. I 
have not been able to demonstrate that the stomata were open by 
