1917] AGRICULTURAL BOTANY. 225 



and discussed, it is claimed that such an aquatic plant as Elodea can be made 

 to give up an appreciable amount of calcium to a solution of potassium chlorid 

 or ammonium chlorid in which it is kept for 30 minutes. This decalcifying 

 action is accompained with the fixation by the plant of a portion of the cations. 

 Salts of other alkali metals can withdraw calcium, and the action is said to 

 be reversible. 



The relations between the presence of magnesium and assimilation in 

 leaves, G. AndriS (Compt. Rend. Aca-d. Sci. IParis], 162 {1916), No. 15, pp. 

 563-566) .—Having followed up the work of Willstatter (B. S. R., 24, p. 329; 

 30, p. 311) and Mameli (E. S. R., 35, p. 435) bearing upon the alleged relation 

 of magnesium to chlorophyll in leaves, the author found that the absolute maxi- 

 mum of magnesium present in the leaves was attained in horse chestnut and 

 lilac May 4 and May 3, respectively, and in chestnut April 26. If the ratio be- 

 tween organic and residual magnesium be considered, these plants attaine*^ 

 their respective maxima May 26, May 3, and June 14. 



A labile form of albumin and its relation to living protoplasm, O. Loew 

 CBiochem. Ztschr., 11 (1915), No. 4-5, pp. 306-320).— It is claimed that there 

 is present in the cell sap, and even in the cytoplasm of many plant cells, a very 

 labile albuminous body which is differentiated from ordinary albumin in that 

 it may be separated by means of ammonia and organic bases from the solution, 

 after which, as a rule, it quickly undergoes a change resulting in a stable com- 

 pound. This labile and active form of albumin reacts toward coloring agents 

 as does living protoplasm, while the protosomes coagulated by heat, acids, 

 alcohol, or other means behave like killed protoplasm in the presence of stains. 

 The intimate relation between the stored labile albumin and the organized 

 labile albumin or living protoplasm is said to be shown in many ways. 



The organic nutriment of green flowering plants, T. Bokoeny (Biochem, 

 Ztschr., 71 (1915), No, 4-5, pp. ^i-S/S-^).— Considerable data have been ob- 

 tained by the author regarding the ability of several common plants to utilize 

 organic products, including some such as supposedly correspond to the products 

 of decay in humus soils. 



Betention of chlorophyll in yellowed and fallen autumn leaves due to 

 attack by animal parasites, O. Richtee {Ztschr. Fflanzenkrank., 25 {1915), 

 No. 7, pp. 385-392, figs. 2). — Instances of retention of green color in case of 

 certain trees by autumn leaves in spots attacked by insects, etc., are discussed. 

 The phenomenon may be due to an interruption of the conducting vessels or 

 possibly to the production of certain substances by animal parasites. 



Abscission in Mirabilis jalapa, F. E. Lloyd {Bot. Gaz., 61 {1916), No. S, 

 pp. 213-230, pi. 1, figs. 2). — The author concludes a study of M. jalapa with the 

 claim that in this case abscission is not brought about by a separation resulting 

 from the complete solution and destruction of a layer of tissue, but that the 

 mode of abscission agrees in all essential details with that shown to occur in 

 Gossypium and Ai'istolochia. 



Abscission, F. E. Lloyd {Ottawa Nat., 28 {1914), Nos. 3-4, pp. 41-52, figs. 3; 

 5-6, pp. 61-75). — A lecture delivered before the Ottawa Field Naturalists' Club, 

 on January 27, 1914, which includes the results of observations on about 30 

 species of plants with special reference to the mechanism of abscission. 



Daily transpiration during the normal growth period and its coirelation 

 with the weather, L. J. Bbiggs and H. L. Shantz {U. S. Dept. Agr., Jour. Agr. 

 Research, 7 {1916), No. 4, pp. 155-212, pis. 2, figs. 18). — An account is given 

 of investigations on the daily transpiration of a part of the plants included in 

 the water requirement experiments at Akron, Colo., in 1914 and 1915 (E. S. R., 

 34, p. 522). The principal objects of the investigations were to determine the 



