524 EXPEKIMENT STATION RECORD. 



ration in tlie tubers, but that catalase activity in the potato juice shows a very 

 striking correlation witli respiratory activity in the tubers. 



The role of oxidases in respiration, G. B. Reed (Jour. Biol. Chem., 22 (1915), 

 No. i, pp. 99-111, pi. 1). — Studies made on several plants are held to show that 

 the oxidation of 1 per cent Spitzer's reagent (an aqueous solution of 1 per 

 cent paraphenylenediamin and saturated a-naphthol) in plant cells frequently 

 proceeds most rapidly in the region of semipermeable membranes, although 

 in many nuclear and all the plastid surfaces observed such activity was absent. 

 The oxidation is not prevented by the destruction of the membranes, but is 

 stopped by the addition of agents which inhibit oxidases. 



Experiments with animal tissue are said to indicate that oxidase enzyms are 

 the active agents in the intracellular oxidation observed to proceed after 

 the destruction of the membranes but not after the inhibition of the oxidases. 



The view is expressed that if the formation of indophenol may be taken in 

 general as a measure of the total oxidative activity of the cell, it may be con- 

 cluded that the oxidases are the essential agents in bringing about this reaction. 



The distribution of invertase in beets at different stages, H. Colin {Compt. 

 Rend. Acad. Sci. [Paris], 160 (1915), No. 2^, pp. 111-779).— It was found'that in 

 normal beets of the first year, the amount of invertase increased from zero at 

 the collar through the petioles to a maximum in the leaf blades. The central 

 leaves showed the largest proportion, which, however, was slightly exceeded by 

 that in leaves bleached in darkness. 



In beets of the second year's growth, invertase increased from zero at the 

 collar through the lower and higher portions of the stem and the leaf blades, 

 reaching the maxinumi in the inflorescences. 



Studies on phototropism, W. H. Akisz (Rec. Trav. Bot. Nierland., 12 (1915), 

 No. 1-2, pp. ff.'f-216, pi. 1, figs: 17). — This is an extended account of a .stuily on 

 phototropism in A vena seedlings exposed to illumination from one, two, or all 

 sides, the results from wliich are discussed in considerable detail. 



The final hydrogen ion concentrations of cultures of Bacillus coli, W. M. 

 Clark (Jour. Biol. Chcm., 22 (1915), No. 1, pp. S7-9S, fig. i).— A further study 

 by the author of the organisms employed in the work reported by himself in 

 connection with Rogers and Evans (E. S. R., 33. p. Kil ) is describetl, in which 

 the final hydrogen concentrations attained in the fermentation of dextrose and 

 lactose by several cultures of B. coli in a variety of media have been measured 

 electrometrically. 



The values obtained agree remarkably for any given medium, and the final 

 hydrogen ion concentrations differ so little that this work is considered as con- 

 firming the claim that the final hydrogen ion concentrations are a physiological 

 constant for B. coli. The differences which are observed to occur must, however, 

 it is thought, be taken into serious consideration in dealing in any rigid way 

 with the specific effects of the hydrogen ion. It is considered that for certain 

 practical purposes the final hydrogen ion concentrations furnish data of much 

 greater significance than can be obtained by the employment of titrimetric 

 methods to measure the acid productivity of these organisms. 



Recent observations on the chondriosomes of epidermal cells of the flowers 

 of Iris germanica, I, II, A. Guilliermond (Compt. Rend. Soc. Biol. [Paries], 

 78 (1915). No. 9. pp. 2.'/l-2-',9. figs. 17). — The author describes and figures the 

 various stages of development of chondriosomes in epidermal cells of /. gcr- 

 mariira, the elaboration of starch, xanthophyll. oil globules, etc.. thereby, and 

 the transformation of the chondriosomes into chromoplasts. Brief discussion 

 Is also given of the technique employed, which is claimed to render these obser- 

 vations easy of verification. 



