308 BOTANICAL GAZETTE [APRIL 
would call it the Boreal realm, of which the Arctic region constitutes a part. In 
the southern hemisphere we have a corresponding Austral realm, of which the 
Antarctic region is a subdivision. What SKOTTSBERG now calls the Austral zone 
is a region that may be designated as Patagonian, or Fuegian, or Magellanian, 
or by some other local name, and which is a division of equal rank to the Ant- 
arctic, subordinating this and several other regions under the term Austral 
realm. Our criticism here refers to the use of the terms only, not to the author's 
definition or limitations of the areas under consideration. In regard to the flora 
of the South Atlantic ocean, the author considers that the division into Austral 
and Antarctic is just as evident as in the land flora. Until the detailed results 
of the expedition are made known and until this question is thoroughly discussed, 
final judgment in the case must be reserved.—OLssON-SEFFER. 
IN A PAPER READ before the B. A. A. S. last August, CZAPEK presents’ @ 
fuller account of his researches on the anti-ferment reaction which occurs in 
tropistic movements, especially of roots. In geotropically stimulated roots, for 
instance, homogentisinic acid, a product of decomposition of tyrosin by tyrosinase, 
accumulates slightly, instead of being oxidized at once, because an anti-enzyme is 
produced by the stimulation, which inhibits the action of the oxidase. The quant 
tative determination of the homogentisinic acid is not practicable as a measure of 
the reaction, but a solution of homogentisinic acid may be used as a reagent for 
determining by titration the retardation of its oxidation by the anti-oxidase. The 
roots to be tested are ground in water with powdered glass to a thin paste, and a 
standard solution of homogentisinic acid added; the initial reducing power of the 
wash is determined. and repeatedly at intervals of five days, by titration with 
n/to AgNO3. Czapex finds that only tropisms produce the anti-enzyme; 
narcosis, poisoning, mechanical hindrance of growth, and wounding having failed 
by themselves to produce the reaction. Six minutes was determined to be the 
limit for roots placed horizontal at 17° C. to show the anti-enzyme reaction, which 
persists for about four hours. Though not observably intensified by prolonged 
stimulation of the root, it persists for a much longer time, even up to thirty Liesl 
after fifty minutes stimulation. The reaction becomes certain for thirty minutes 
induction at an angle of 7° from the normal and at 10° is maximal, remaining con- 
stant up to 170°; decreasing very much at 176°, and not showing at all at 180°. 
By reducing the time of induction it can be shown that the reaction is stronger 
at 135°-150° than at horizontal, which assists in settling a disputed point. Roots 
rotated on the klinostat show the reaction, clearly supporting the view that a 
tropic stimulation occurs under such conditions though curvature does not resv a 
This reaction also confirms CzAPEK’s experiments with glass slipper, esis 
that more than the root cap with its statolith cells is involved in the | uaeeilll 
phenomena. He lists these phenomena (assuming them to be consecutive) thus: 
x6 CzZAPEK, F., The anti-ferment reaction in the tropistic movements of plants 
Ann. Botany 19:75-98. 1905. 
