AGRICULTURAL CHEMISTRY — AGROTECHNY. 311 



of fat by Penicillium glaucum. The subject is considered under the following 

 headings: The taking up of fatty acids and glycerol by the cells of the 

 fungus; the cleavage of glycerol; the cleavage of fatty acids; assimilability 

 of fatty acids and molecular synthesis; and the changes produced in the con- 

 stants of fat through the agency of molds. 



The tannins, J. Dekkkr (Dig Gerbstoffc. Berlin, 1913, pp. XIII-\-636, figs. 

 S).— This is a large botanical-chemical monograph on the tannins. The first 

 part of the book (pp. 1-292) deals with the literature pertaining to the tannins, 

 and tannin substances and their botiiuy, considered from the standpoint of 

 physiology. The occurrence and significance of the tannins, etc., are discussed. 



The second part of the book (pp. 295-586) considers the subjects under the 

 following headings: Tannin and the taunoids; substances from which tannins 

 originate; chemical classification, definitions, reactions, and properties; quan- 

 titative analysis; and the use of tannins in the arts, sciences, and indu.stries. 



Investigations about chlorophyll, R. Willstatter and A. Stoll {Unter- 

 siK'huyipcn iiher ChloroplujU. licrUn, 1913, pp. VIir+Jf2Jf, pis. 11, figs. 16). — 

 This work comprises unpublished investigations which have been conducted dur- 

 ing the last years by the authors and deals with methods and results. It dis- 

 cusses the subject under 3 headings, namely, the isolation of chlorophyll, the 

 separation and quantitative determination of all the components of the coloring 

 matter of leaves, and the hydrolysis of chlorophyll. A large bibliography is 

 included. 



Principles of ferment methods, J. Wohlgemuth {Grundriss der Ferment- 

 inethoden. Berlin, 1918, pp. IX-^355). — A text-book on the subject designed for 

 physicians, chemists, and botanists, and divided into a general and special part. 

 The general part deals with the nature and properties of ferments or enzyms, 

 the general principles involved in enzym investigations, the preparation of 

 solutions of ferments and the isolation of ferments, and a chapter on filtration 

 and dialysis. The special part considers carbohydrate-splitting ferments (fer- 

 ments cleaving polysaccharids, trisaccharids, disaccliarids, and detection of 

 monosaccharid-splitting ferments) ; fat-splitting ferments (lipases and ester- 

 ases) ; protein-splitting ferments; ferments cleaving nuclein and nuclein bases; 

 oxidases; catalase; and coagulation of the blood. 



The reversibility of ferment action, E. Boubquelot (Rev. G6n. Sci., 2^ 

 {1913), No. 18, pp. 687-693, fig. 1).—A discussion of this topic, with special 

 reference to the work of the author and his coworkers. The significance of the 

 reversibility of ferment action for chemistry and physiologj^ is pointed out. 



Action of sucrase from koji in the presence of various acids, G. Bertrand 

 and Frau Rosenblatt (Abs. in Chem. Ztg., 37 {1913), No. 36, p. 566).— Sucrase 

 obtained from koji shows its greatest activity in those solutions in which the 

 hydrogen ion concentration of the solution corresponds to the neutral point of 

 helianthin. 



Action of hydrog-en peroxid upon the amylase of woman's milk, L. Lagane 

 (Compt. Rend. Acad. Sci. [Paris], 156 {1913), No. 25, pp. 19^1-1 9.',3).— The addi- 

 tion of hydrogen peroxid in small amounts to raw human milk accelerates the 

 starch liquefying power and to a lesser extent increases the saccharifying 

 power of amylase. 



The significance of hydrogen ions for the rennet and acid coagulation of 

 milk, O. Allemann (Biochem. Ztschr., Jf5 {1912), No. 3-.J, pp. 346-35S; abs. in 

 Chem. Ztg., 36 {1912), No. 88, p. 841). — The procedure followed was Van Dam's 

 (E. S. R., 20, p. 1178), but as the results obtained with milks having additions 

 of acids were unsatisfactory, it was necessary to add to the milk a reaction 

 regulator which consisted of sodium acetate-acetic acid mixtures of different 



