1915] ROSE—APPLE BARK 65 
conclusion seems justified that oxidation is in approximately inverse 
ratio to the acidity of the extract-in = range of concentrations 
here used. 
3. This conclusion is borne out by the fact that addition of acid 
to the solution in the apparatus decreases oxidation and addition 
of alkali increases it. 
4. Oxidases are very sensitive to small variations in acidity of 
the solution in the oxidase apparatus. 
5. As a hypothesis in need of further proof the following is 
offered. The gradual slowing down of oxidation in the BUNZEL 
apparatus is brought about by accumulation of oxidation products, 
probably acetic and oxalic acids, and not by a using up of the oxi- 
dase through chemical combination between oxidase and oxidizable 
substance. 
Missouri State Fruit EXPERIMENT STATION 
Mountain GROVE, 
LITERATURE CITED 
- Bunzet, H. H., A simplified and inexpensive oxidase apparatus. Jour. 
Biol. Chem. 17:409-411. 1914. 
, The measurement of the oxidase content of plant juices. U.S. Dept. 
Agric. Bur. Pl. Indus. Bull. 238. pp. 5-40. 1912 
REED, H. S., The enzyme sere Aas in certain fruit diseases. 
Va. Exp. Sta. Ros. to11 and 1 . 
: APPLEMAN, C. O., Biochemical ait chjclowe study of the rest period in 
tubers of Solaniat tuberosum. Maryland Agric. Exp. Sta. Bull. 183. p. 193. 
IQr4. 
- Scutey, Eva O., Chemical and een changes in geotropic stimulation 
and response. Bow, GAz. 56: 483. 
Hoéser, Rup, Physikalische Chee ded Zelle und der Gewebe. Leipzig 
und Berlin. 1914. 
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