626 EXPERIMENT STATION EECOED. 



and tbus iu iucreasiug the transpiration of plants (but not their growth). Ihe 

 retention of water is the physiological function correlated with and indis- 

 pensable to growth in general, and to survival and greater areal distribution 

 of the plants entering physically or ])hysiologically arid habitats. 



The tensile strength of sap, H. H. Dixon (Sci. Proc. Roy. Dublin Soc, n. 

 ser., 14 {1914), ^0. 16, pp. 229-234). — The author has investigated the tensile 

 strength of the sap of beech and other trees and found that it does not differ 

 materially from that of water. In the few experiments made the ease with 

 which tension was generated and its magnitude before rupture occurred are 

 believed to indicate that sap is somewhat more stable under tension than pure 

 water. 



Oxidases and their inhibitors in plant tissues, I— III, ^Y. R. G. Atkins 

 (Sci. Proc. Roy. Dublin Soc, n. ser., 14 {1913), No. 7, pp. 144-156; 14 {1914), 

 Nos. 8. pp. 157-168; 11, pp. 199-206). — The author has given a detailed account 

 of investigations on the distribution of oxidases iu certain tissues, a large num- 

 ber of plants having been examined. 



Special studies were conducted on the occurrence of oxidase in Iris geriimnica. 

 It was found that in the leaf of this plant there exists a substance which pre- 

 vents the detection of oxidases by the direct application of guaiacum solution 

 and hydrogen peroxid. 



In the second paper the author reports studies to determine qualitatively the 

 effect of light and darkness upon the oxidases and reducing substances of the 

 Iris leaf and their relationship to the production of color in the flower of Iris. 

 Prolonged darkness is said to have no decided effect upon the distribution of 

 the indirect oxidase (pei'oxidase) reactions or of the inhibitor in the leaf of 

 I. germanica. The distribution of the oxidase and inhibitor in the flowers of a 

 number of varieties of Iris was examined and correlated with the natural color- 

 ing of the flowers, the author concluding that the behavior of Iris flowers 

 closely follows that of other species reported by Keeble. Armstrong, and Jones 

 (E. S. R., 29, p. 421; 30, p. 129). 



The concluding paper gives an account of a study on the localization of 

 oxidases and catalase in some marine algfe. Catalase was found in all of the 29 

 species studied. Oulj- one species gave a direct oxidase reaction with guaiacum 

 while six gave an indirect reaction with hydrogen peroxid. The presence of 

 water-soluble phycophsein in small quantity during life and its reduction to a 

 colorless substance at death is suggested as an explanation of the much 

 discussed color change occuring in brown algap. 



Bibliographies are appended to the different papers. 



The production of anthocyanins and anthocyanidins, A. B. Everest {Proc. 

 Roy. Soc. [London], Ser. B. 87 {1914), ^^0. B 597, pp. 444-452) .—The author, 

 presenting experimental data, claims to have demonstrated the production of 

 anthocyanins from j-ellow glucosids and states that in cases where hydrolyzed 

 solutions were taken only anthocyanidins were produced, claiming that these 

 facts with others cited oppose the hypothesis offered by Miss Wheldale (E. S. R., 

 21. p. 726) to the effect that anthocyanin pigments are the oxidation products of 

 colorless or faintly colored chromogens and that these chromogeus are pi'oducts 

 of hydrolysis of glucosids present in the tissues of the plant. Studies previously 

 published by the author in connection with Willstatter (E. S. R., 30, p. 324), 

 also reports by Keeble, Armstrong, and Jones (E. S. R., 30, p. 120), are con- 

 sidered to have shown that if the anthocyanins are produced from the yellow 

 glucosids, it must be by some interaction in which the glucosids and not the 

 hydrolyzed glucosids take part and that anthocyanin pigments are not oxidation, 

 but reduction, products of the yellow glucosids. 



