3] Evaporation of Water from Plants. 309 
Here again it is evident that ‘‘transpiration” is independ- 
ent of assimilation. The greater loss from the green maize 
plant in light as compared with the etiolated one Wiesner 
refers to the fact that the rays of light absorbed by the 
chlorophyll of the green plant are converted into heat, a con- 
version which is not effected to the same extent by the etolin 
of the etiolated plant. If we now stop assimilation by any 
means the 785™" lost in the sunlight from the green Zea mais — 
would, according to M. Jumelle, be increased, showing again 
that transpiration does not increase directly with assimilative 
activity in the protoplasm, but, on the other hand, decreases 
asassimilative activity increases. It is also known that as the 
vitality of the protoplasm decreases it loses its power of re- 
taining water. We are justified, then, in maintaining that 
the excess of the loss of water in the light over the loss in the 
ark, both in green and etiolated plants, is due to the calori- 
fic effect of the light and is therefore purely a physical process, 
evaporation, 
Now in regard to the relation of anesthetics to ‘‘transpi- 
fation” in the dark. M. Jumelle’s results show that the anzs- 
thetized plant loses less water in the dark than the normal 
rm This fact M. Jumelle says he can not satisfactorily 
“seg These results so far as I know have not been ques- 
“a but rather confirmed by other observers. I think, 
ever, that all have made errors in conclusion on this point 
whi 
ara » shall endeavor to correct. The influence of an anzxs- 
on 
Would ex 
s than the normal plant 
of bileherie estion that I made, recently, on the relation — 
found ether to the opening and closing of stomata, I 
dose of preg ven in moderately strong diffused light, a strong 
the action ony closed the stomata. In weak diffused light 
Indica in whiey od, ™tKed, especially so in the leaf of Canna 
brought a ich the stomata closed almost instantly when 
prone the influence of ether. These experiments were | 
these ex gcd times with essentially the same results. If, as 
tad indicate, the stomata of anesthetized plants — 
femaj é 
" closed in the dark, we could readily understand why 
