AGRICULTUKAL CHEMISTRY — AGROTECHNY. 309 



upon a wire netting and lieated slowly with a small flame of a Bmisen burner. 

 If alcohol is present the characteristic oil-drop effect will be noted in the tube. 



On the presence of yeasts in fermenting- tea and their probable influence 

 on the aroma of tea leaves, C. Bernard (Buh Dipt. Agr. Indes Nierland., 

 1910, No. 36, pp. 42, pJs. 4) 0&-S- i'^ Internat. Inst. Agr. [Rome], Bid. Bur. Agr. 

 Intel, and Plant Diseases, 2 (.1911), No. 1, p. 103). — Micro-organisms in addi- 

 tion to unorganized ferments probably take part in the development of the 

 aroma in tea. A yeast which almost always occurs among the other micro- 

 organisms upon Java tea leaves was isolated. This seemed to have a favorable 

 influence upon the fermentation process. The bacteria are harmful to the 

 product. 



The chemical composition of enzyms and their formation, II, H. Euleb 

 and Beth af Ugglas (Hoppe-Scyler's Ztschr. Physiol. Chcni., 10 (1911), No. 

 4-5, pp. 279-290; abs. in Zentbl. Gesam. Physiol, u. Path. Stoffivechsels, n. ser., 

 6 (1911), No. 10, p. 4^2). — It was found to make very little difference whether 

 the water was removed from yeast by drying in vacuum or with absolute alco- 

 hol, and it is shown that Buchner's permanent yeast preparation can be taken 

 as a measure for the study of the rate and the intensity of the activity of the 

 invertase extracted from the yeast. Although the action of phosphates upon the 

 activity of invertase is well known, the authors point out that the reaction of a 

 medium, whether acid or neutral, has some influence upon this activity also. 

 In a neutral medium the inversion goes on from 2 to 7 times quicker than in an 

 acid medium. If the yeast is not dried a higher degree of fermentation is 

 obtained by the addition of phosphates. 



The authors as a result of their work set up the following hypothesis: 

 Zymase exists in living yeast either partly or wholly as a chemical complex, 

 which is bound to the protoplasm and the activity of which is checked partly 

 or permanently when the vital process of the cell is hindered. The free portion 

 (or that portion which is liberated during the dehydration process of the fer- 

 mentation enzym) is the only one which is active during the process. The 

 authors doubt the possibility of regenerating zymase. 



Investigations in regard to the chemical composition and formation of 

 enzyms, III, H. Euler and S. Kullberg (Hoppe-Seyler's Ztschr. Physiol, 

 Chem., 71 (1911), No. 1, pp. I4-SO; abs. in Zentbl. Biochem. u. Biophys., 11 

 (1911), No. 21-22, pp. 896-898) .—This article deals with the influence of phos- 

 phates upon the invertase- and zymase-system of living yeast cells and the 

 dynamics of enzym reactions caused by these cells. 



Action of the compounds of chromium and salts of magnesium, manga- 

 nese, iron, and aluminum upon the amylolytic ferments, C. Gerber (Compt. 

 Rend. ^oc. Biol. [Paris], 70 (1911), No. 16, pp. 724-730; abs. in Zentbl. Biochem,. 

 u. Biophys., 11 (1911), No. 20, p. 849). — Chromates were found to accelerate 

 amylolysis up to a certain concentration, but above this concentration the action 

 of the ferment is retarded. The accelerating action is combined with the action 

 of acids, and the retardation is due to a destruction of the diastase. Neutral 

 chromates in small quantities were found to act indifferently. Tlie retarding 

 action of large amounts of dichromates or neutral chromiuni salts was found 

 not to be due to the destruction of the diastase. The same holds true for mag- 

 nesium salts and manganese. Ferrous salts only retard the action of diastase, 

 while ferric salts and aluminum compounds behave like the chromates. 



The action of the alkali metal salts upon the saccharifi.cation of starch 

 by proteolytic ferments. — IV, Neutral ammoniacal salts, V, Carbonates 

 and bicabonates. VI. Salts of rubidium, caesium, and lithium, C. Gerber 

 (Compt. Rend. Soc. Biol. [Paris], 70 (1911), No. 18, pp. 822-828; abs. in Zentbl. 

 Biochem. u. Biophys., 11 (1911), No. 23, p. 945). — Neutral ammonia salts in 



