320 PHYSIOLOGY [BoT. Absts., Vol. VIII, 



and (2) the relative concentration of enzymes, sugars, organic acids, and tannins in extracts 

 being different from that existing in situ. If inhibitors are present, they must be removed. 

 The following technique was employed by the author: (a) Reaction of tissues. Pieces of tis- 

 sue were placed directly in the reagents, — alcoholic solution of guaiacum, 1 per cent solution 

 benzidine in 50 per cent alcohol with H2O2, 1 per cent a-naphthol in 50 per cent alcohol with 

 H2O2. (b) Reaction of water extract. Water extract of pounded tissue was tested in above 

 reagents, and if acid it was neutralized to litmus, (c) Reaction with extracts of enzymes. 

 Sugars, tannins, etc., were extracted from pounded tissue with 96 per cent alcohol and the 

 enzyme extracted from the residue with water. This was tested for peroxidase with guaiacum 

 and H2O2, and for oxygenase with catechol and guaiacum. (d) Extraction of aromatic com- 

 pounds and their reaction with enzyme extract. Employing methods outlined above, the follow- 

 ing fruits were tested for oxidizing enzymes : Apple, quince, pear, plum, banana, orange, lemon, 

 lime, and raspberry. The apple, pear, quince, and plum were found to contain an oxidase 

 (peroxidase, oxygenase, and aromatic substance with catechol grouping). Both skin and 

 flesh of banana contained peroxidase and oxygenase ; the orange, lemon, and lime contained per- 

 oxidase in rind and pulp, but no oxygenase and no substance giving the catechol reaction. 

 Raspberry fruit gave similar results. — A. R. Davis. 



METABOLISM (RESPIRATION, AERATION) 



2182. Bekgman, H. F. The effect of cloudiness on the oxygen content of water and its 

 significance in cranberry culture. Amer. Jour. Bot. 8: 50-58.3^^. 1921. — A study of the oxy- 

 gen and CO2 content of pond and bog water used in flooding cranberry bogs was made in Wis- 

 consin and Massachusetts. In general, it was found that oxygen was more abundant and 

 CO2 less abundant (1) during the latter part of the day as compared with the morning, and 

 (2) during clear days as contrasted with cloudy ones. Under the following conditions, namely, 

 (1) clear, sandy bottom pond, (2) muck-bottom pond, and (3) discolored water of a bog ditch, 

 there were, in the order given, more oxygen and less CO 2 and much less variation in the con- 

 tent of these 2 gases. It is suggested that the photosj^nthesis and respiration of plants and 

 the oxidation of organic matter are responsible for the amount of these gases present and that 

 differences in light intensity, amount of vegetation, and amount of organic matter produce 

 the differences observed. Experiments are cited in which cranberry plants, submerged in 

 tubs of either pond or ditch water, were injured by shading, while unshaded plants under 

 otherwise similar conditions were not injured. The oxygen content in the unshaded tubs 

 was much reduced. Respiration (and thus the need of oxygen) was found to be much more 

 rapid in flowers and growing tips of cranberry plants than in old shoots. The injury to grow- 

 ing tips which frequently follows flooding the bogs is thought to be due to deficiency of oxy- 

 gen in the water. Such injuries are more likely to occur if water full of organic matter is 

 used or if flooding is done in cloudy weather. — E. W. Sinnott. 



2183. PiEDALLU, Andre, Phillippe Malvezin, et Lucien Grandchamp. Action de 

 I'oxygene sur les mofits de raisins rouges. [The effect of oxygen on the wine from red grapes.] 

 Compt. Rend. Acad. Sci. Paris 171: 1230-1231. 1920. — Oxygen is found to change the color 

 of the solution to a white or a rose if allowed to diffuse through a porous plate, thus no de- 

 colorizing chemicals are necessary. — C. H. Farr. 



ORGANISM AS A WHOLE 



2184. LiESEGANG, Raphael Ed. Gegenseitige Wachstumshemmung bei Pilzkulturen. 

 [Mutual antagonism in fungus cultures.] Centralbl. Bakt. II Abt. 51 : 85-86. Fig.l. 1920. — 

 The author attributes the gaps that appear between approaching colonies in the well-known 

 phenomenon of "growth antagonism," to a deficiency of an essential nutrient. This nutrient, 

 which must be essential for both approaching colonies, has dift'used in the direction of the 

 growing colonies and no longer exists in sufficient amount to sustain growth. The author has 

 reproduced an analogous phenomenon by using silver nitrate gelatine upon which drops of 

 sodium chloride are placed. — Anthony Berg. 



