AGEICULTURAL BOTANY. 229 



The author shows that A. niycr is sensitive to 1 part in 10,000,000,000 of 

 manganese. On account of this great sensitiveness the author calls attention to 

 the necessity for the use of chemically-pure substances in culture media. The 

 ordinary iron sulphate of commerce is said to contain from 0.2 to 0.5 part in 

 1,000 of manganese. 



The poisonous action of oxalic acid salts and the physiological action of 

 calcium, O. Loew (Biochem. Ztschr., 38 (1912), No. S-Jf, pp. 226-243).— As a 

 result of this extension of his former investigations, now made on seeds, shoots, 

 and roots of several cultivated plants, on the leaves of aquatic plants, and 

 on various algje and fungi, as well as lower water animals, the author announces 

 that i)otassium oxalate exerts a poisonous influence upon the most diverse plant 

 forms (exclusive of the lowest algte and fungi which also require no calcium). 

 A relation is argued between the physiological significance of calcium comiwunds 

 and the injurious effects of oxalates. Observations show that the injurious 

 reaction of the latter manifests itself in the cell nucleus and the chloroplasts, 

 from which he infers the presence of a compound of calcium in such vegetable 

 cells (as in lower animal ceJls which exhibit physiological analogies in this 

 respect). 



Effects of basic compounds on seedlings and on the lower organisms, T. 

 BoKORNY (CenthJ. Bait, [etc.], 2. Aht., 32 (1912). Xo. 20-25, pp. 637-605).— 

 The author, in pursuance of previous studies (E. S. R.. 25, p. 433), investigiy:ed 

 the influence of various dilute basic compounds on the development of seedlings 

 and of micro-organisms. It was found that, while solutions of 0.01 to 0.25 

 per cent prevented or retarded development in case of nearly all compounds 

 studied, ammonium chlorid exerted the most deleterious effect, and that such 

 effect was noticeable in the very lowest concentrations of this salt tested. 



Movement of minerals in autumn leaves, E. Ramann (Landw. Vers. Stat., 

 76 (1912), No. 3-6, pp. 157-16-'i). — The author's analyses, at suitable intervals, 

 of leaves of beech, oak, hazel, and birch, led him to conclude (1) that, in the 

 normal dying of leaves in autumn, there is a considerable movement of pro- 

 teins from the leaves to the stem; (2) that the movement of potassium and 

 the movement in considerable quantity of phosphoric acid in the same direction 

 seems to be influenced by the nourishment of the stem; (3) that lime and 

 silica about double in quantity in the leaves before death; (4) that these 

 transfers take place during the short period of yellowing and dying; and (5) 

 that these exchanges are more significant in the life of the plant than has com- 

 monly been held by investigators. 



Mineral movements on freezing of leaves, E, Ramann (Landw. Vers. Stat., 

 76 (1912), No. 3-6, pp. 1\65-167). — Continuing the above studies, the author 

 reports upon the effects of freezing the leaves of oak, pine, and fir on the 

 translocation of mineral substances. The partial freezing of the foliage, October 

 IS, 1909, made it possible to compare not only injured and uninjured leaves 

 of the same tree but also frozen and unfrozen parts of the same leaves. 



As a result of his comparative analyses of the ashes of leaves taken while 

 living and of frosted leaves, he reports (1) that both the protein and the 

 sulphur contents of the leaves remained unchanged on freezing; (2) that 

 potassium and phosphoric acid were considerably decreased; (3) that calcium 

 was added in large quantity as in regular autumn dying of leaves; and (4) 

 that these changes occurred in the very short interval between thawing and 

 drying out, which fact is pointed to as an illustration of the possibilities of 

 rapid transportation in dying or dead leaves. 



Smoke, fumes, and cultivated soil (Rev. Set. [Paris], 50 (1912), I, No. 10, 

 pp. 311, 312). — Brief reference is made to investigations by Wieler on the 



