AGRICULTURAL CHEMISTRY — AGROTECIIN Y. G13 



Determining' the quantity of monoamino acids yielded by proteins when 

 hydrolyzed with acids, T. B. Osborne and D. R. Joxks (Aiiui: Jour. Phi/sioL, 

 26 (1910), Xo. 2, pp. 212-228).— The results of modifications of the usual meth- 

 ods of aualyzius proteins are reported. The object of the modifications was to 

 obtain a more nearly quantitative method of determining the monoamino acids, 

 or a larger proportion of the still unknown substances among the products of 

 hydrolysis. Zeiu was the proteid used in the study. 



Investig-ations in reg'ard to the practicability of utilizing anaphylaxis 

 for differentiating various proteids, Uhleniiutii and Haendel (Zt.^chr. 

 Immunitlitsf. u. Expf. Thci:, I. Orifj., /, (1910), No. 6, pp. 761-816).— The ana- 

 phylaxis reaction whether passive or active is not applicable to the differentia- 

 tion of related blood types. The reaction, however, may be of value to sub- 

 stantiate the findings of the precipitation tests with certain proteins or in 

 instances where (for technical reasons or where denaturized protein is in ques- 

 tion) it is inconvenient to apply the complement binding reaction or the pre- 

 cipitation test. 



Concerning our method of nitrogen estimation, E. A. Mitscherlich (Laiulw. 

 Vers. Stat, 72 {1910), Xo. 5-6, pp. .J.59-/,6^).— A reply to Zeller's criticism 

 (E. S. R., 22, p. 609). 



A source of error in estimating' ammonia, E. Barral (BuI. Soc. Chun. 

 France, J,, ser.. 7 (1910), Xo. 1, pp. 8, 9; abs. in Jour. Clicm. Soc. [London], 98 

 (1910), No. 568, II, p. 755).— When using Schloessing's method in the determina- 

 tion of nitrogen as ammonia it was found that new block-tin condensers absorbed 

 much ammonia, and accurate results were obtained only after they had been 

 in use for a certain length of time. Tests with granulated tin showed only a 

 A-ery slight absorption of ammonia, and from this the author concluded that 

 the error was probably due to the presence of grease or tin oxids in the new 

 tubes. 



The gravimetric determination of the phosphates, A. H. iLvrnn (Chcm. 

 Xeics, 101 (1910), Xo. 2635. p. 2-il; abs. in Chcm. Ztg., 3', (1910), Xo. 69, 

 Repert., p. 275).— Woy's method (E. S. R., 14, p. 1042; 15, p. 122) is recom- • 

 mended instead of the magnesium-pyrophosphate method on account of its 

 rapidity of execution and more accurate results. The precipitate obtained by 

 double precipitation with ammonium niolybdate in the presence of ammonium 

 nitrate and in a nitric acid solution is collected in a Gooch crucible, placed in a 

 nickel crucible containing some asbestos, and heated at a I'ed heat for 20 min- 

 utes. The weight of the blue-black mass obtained, multiplied by 0.0o94G7 (log 

 2.59623), equals the weight of i)hosphoric acid (P^jO^). 



The exact determination of sulphur and of barium in the presence of 

 alkali salts, I. K, Phelps (Abs. in Science, n. ser., 31 (1910), Xo. 807, p. 960).— 

 " By precipitating with Bad- in a hot, neutral solution the contamination of 

 BaSOi with foreign negative ions may be almost completely avoided and the 

 precipitate contaminated with such positive ions as K, Na or NIL converted into 

 pure BaSO. by treatment with ILSOi. evaporation, and extract ion of the alkali sul- 

 plate with water. In determining sulphur this alkali sulphate is converted into 

 BaS04 by addition of the water extract to the mother li(iuor of the first pre- 

 cipitate. This second precipitate of BaSO, is added to the first and the process 

 repeated. In determining Ba the water extracts are rejected." 



Some improved methods of dairy chemistry analysis (Wiscnn.iin Stn. Re- 

 search Bill. 10, pp. 107-125). — This contains three papers, previously noted from 

 other sources, as follows: (1) A volumetric method for the estimation of casein 

 in cow's milk, by E. B. Hart (E. S. R., 21, p. 61.3) : (2) The quantitative estima- 

 tion of lactic acid in Cheddar cheese, by S. K. Suzuki and E. B. Hart (I-l S. R., 

 22, p. 414) ; and (3) The relation of different acids to the precipitation of casein 



