524 BOTANICAL GAZETTE [DECEMBER 
knowledge of the factors affecting oxidase activity, but the true value of this 
contribution would have been better shown by a fuller reference to other work. 
STLE and BUCKNER" report experimental proof that phenolphthalein 
can be oxidized in the living plant. This they take to mean that free active 
oxygen is present in the tissues, apparently overlooking the possibility that 
combined oxygen might have caused the results observed. The reagent used, 
on oxidation, yields phenolphthalein, which is easily recognized by the pink 
color it gives with alkalies. When this test was applied to stalks of Indian 
corn which had been injected with the reagent, the pink color was found local- 
ized in the fibrovascular bundles of the stem and leaves. It was not found in 
the tassel, although lower down, close to the point of injection, there had been 
some diffusion into the cells adjoining the fibrovascular bundles. Similar 
results as to place of oxidation were obtained with okra. 
The method here used offers a means of attacking the problem of oxidation 
in plants which should yield other valuable results if further developed and 
applied to a wider series of plants. It would be worth while to try whether 
phenolphthalein can be oxidized in the living plant when used in neutral or 
acid solution, and if so whether the oxidation is localized in particular cells 
or tissues. Such a test would allow for the effect of reaction (acidity or alkalin- 
ity), a factor known to be of great importance, not only in oxidation processes, 
but also in other processes carried on in living tissues. The effect of reaction 
might also be studied in acid fruits and in tissues affected by “physiological 
diseases’’ or by diseases due to bacterial or fungus parasites. In several cases 
such tissues have been found to be less acid than healthy ones, but little is 
own concerning variations in reaction within the tissues themselves.— 
D. H. Rose. 
Experiments in girdling.—A contribution by HrB1No” is of interest both 
to plant physiologists and horticulturists, since it will aid in furnishing a more 
definite chemical basis for the interpretation of the behavior of girdled plants. 
In the past there has been no lack of references to the accumulation of elabo- 
rated foods above the girdles; it is certainly worth while to have some definite 
determinations of these compounds and their relative quantities. 
Five types of girdling were tried on Cornus contraversa Hemsl. These con- 
sisted in (1) removing a complete ring of bark, (2) removing a complete ring of 
bark and some of the wood, (3) removing half a ring of bark, (4) removing half a 
ring of bark and wood, and (5) boring completely through the wood. The 
wounds were left unprotected. The last three methods of treating the material 
resulted in responses similar to the untreated controls in nearly all cases. 
The genera] external results noted are those commonly recorded in girdling 
experiments. The main interest of the present paper centers in the presenta- 
Kastte, J. H., and Buckner, G. Davis, Evid { the action of oxidases within 
the living plant. tone Amer. Chem. Soc. 39:479-482. 
 HIBINO, Sutn-Icut, Effekt der Ringelung auf ie eae bei Cornus 
controversa Heil: Jour. Coll. Sci. Imp. Univ. Tokyo 39:1-40. pls. 1, 2. 1917- 
