Varietäten, Descendenz, Hybriden. — Physiologie. 183 



diese als einen Hemmungsfaktor an, der demnach spontan wegfällt. 

 Seine Gegenwart unterdrückt die erwähnte stärkere Begrannung 

 und Behaarung, sein Wegfall lässt sie erscheinen und liefert eine 

 scheinbar positive Mutation. Fruwirth. 



Appleman, Ch. O., Some observations on catalase. (Bot. 

 Gaz. L p. 182-192. flg. 1. Sept. 1910.) 



After a general discussion of the distribution and function of 

 catalase a detailed description of the methods used in the investi- 

 gation is given. The rapid degeneration of the catalase is overcome 

 by grinding and storing with calcium carbonate. The results are 

 summarized as follows: 



1. Comparable quantitative determinations of potato catalase can 

 be made in the fresh extracts, if the material is ground with cal- 

 cium carbonate, the extract diluted immediately with ten parts 

 of water to one of extract, kept at 20° C. or below, and the same 

 time maintained for the grinding of the potato and the catalase 

 determination. 



2. An insoluble (^4-catalase) and a soluble (Z?-catalase) form may 

 be separated by ordinary Alter paper. Approximately 50 per cent 

 of the total passes through. None will pass through a Chamberland- 

 Pasteur fiilter. 



3. The Van 't Hoff velocity coefficient for potato catalase is 

 1.5 from 0°C. to 10° C. At higher ranges of temperature there is an 

 apparent progressive decrease in the velocity coefficient. This is 

 due to actual destruction of the catalase, which is not due in the 

 main to impurities in the hydrogen peroxide or to oxidation by the 

 hydrogen peroxide. 



4. Potato catalase is not un limited in its power to effect the 

 decomposition of hydrogen peroxid. It seems to be consumed in the 

 reaction and a given amount is capable of decomposing a definite 

 amount of hydrogen peroxid. 



5. The catalase activity bears a relation to the respiratory 

 activities in the potato, decreasing under the same conditions as 

 respiration. Moore. 



Bailey, I. W., Oxidizing enzymes and their relation to 

 "sap stain" in lumber. (Bot. Gaz. L. p. 142—147. Aug. 1910.) 



Sap stain may be due to either fungi or chemical discoloration 

 due to an oxidizing enzj^me. This enzyme may be destroyed by a 

 temperature of 100° C. and consequently treating the sap wood with 

 boiling water prevents sap stain. Treating lumber in tanks of boi- 

 ling water is practical and may be adapted to saw mill practics. 



Moore. 



Briggs, L. J. and H. L. Shantz. A wax seal method for 

 determining the lower limit of available soil moisture. 

 (Bot. Gaz. LI. p. 210—219. fig. 1—2. March 1911.) 



It was found in attempting to determine the non-available 

 moisture content of the soil that the soil should be as uniform as 

 possible and should be brought to a uniform water content before 

 being used. All loss of water except that due to transpiration of 

 the plant should be prevented and sudden fluctuations in tempera- 

 ture must be avoided. It must also be definitely ascertained that 



