422 BOTANICAL GAZETTE [JUNE 
under similar conditions. In spite of the greater amount of water 
absorbed, the rusted shoot was more or less flaccid, while the 
healthy shoot maintained a turgid condition. This behavior 
might be regarded as a consequence of the condition produced by 
the caeoma type of sorus produced by the fungus in question. 
The rupture of more or less extensive areas of the ventral epidermis 
of the leaf obviously facilitates the evaporation from the spongy 
parenchyma layers. Possibly other factors connected with the 
diseased condition may also operate to cause increased transpiration. 
While not strictly parallel, it may be proper in this connection 
to cite results which BuRGERSTEIN’ obtained with the use of dilute 
solutions of camphor. He found that solutions containing about 
one part of camphor per thousand had an accelerating influence 
upon most plants investigated. Excised shoots, which were pre- 
viously allowed to become somewhat wilted, revived more quickly 
when placed in camphor water than when placed in distilled water. 
By weighing the vessels of water in the two cases, it was shown that 
transpiration from the shoots went on more rapidly in camphor 
water than in distilled water. That camphor was absorbed by the 
excised shoots was shown by their pathological condition and death 
prior to the appearance of any such conditions in the parallel 
series in distilled water. It seems proper to regard this result as an 
example of transpiration under pathological conditions, since the 
deleterious substances thrown off by fungi may act similarly to 
the camphor. 
Results of a somewhat similar import have been reported by 
one of the authors of this paper, showing that substances like tannic 
acid and pyrogallol when present in small amounts accelerate 
transpiration.4 Small amounts of oxalic and acetic acids were 
likewise shown to accelerate transpiration. Since these substances 
are found as such in plants, it is possible that they may influence 
transpiration more or less independently of other factors. 
The studies upon transpiration herein described were conducted 
3 BURGERSTEIN A., Uber einige physiologische und pathologische Wirkungen des 
Kampfers auf die Pflanzen, inbesonders auf Laubesprosse. Verh. Kais. Kin. Zoolog.- 
Botan. Gesells. Wien 343543. 1884. 
4 REED. H. S., The effect of certain chemical agents upon the transpiration and 
growth of wheat seedlings. Bor. Gaz. 49:81. 1910. 
