191T] AGSICULTTJRAL CHEMISTRY AGROTECHNY. 311 



The material is grouped under three major divisions, (1) quantitative deter- 

 mination of the elements, (2) special subjects, and (3) tables and useful data. 

 In tlie chapters on the elements the subject matter is treated in a general way 

 under the headings of physical properties, detection, estimation, preparation and 

 solution of the samples, separations, and gravimetric and volumetric methods. 



Report of the work of the Swiss Agricultural Chemical Institute at Bern 

 (Liebefeld) for the year 1915, P. Liechti (Landw. Jahrb. Schiveis, SO (1916), 

 No. 5, pp. JfS9-508). — This report contains the results of the fertilizer and 

 feeding stuff control work and brief notes on some projects being carried on, 

 chiefly in connection with fertilizers. 



Standard methods for the examination of water and sewage {Boston: 

 Amer. Pub. Health Assoc, 1917, S. ed., pp. XV I +115, fig. 1). — This is a revision 

 of the methods by committees of the American Public Health Association and 

 the American Chemical Society and referees of the Association of Official Agri- 

 cultural Chemists. It includes chemical, microscopical, and bacteriological pro- 

 cedures and a chemical and bacteriological bibliography. 



Applications of a new reagent for the separation of ammonia. — I, The 

 colorimetric determination of ammonia in urine, O. Polin and R. D. Bell 

 (Jour. Biol. Chem., 29 (1917), No. 2, pp. S29S35) .—On account of the impossi- 

 bility of obtaining the charcoal used in the method described by Folin and Denis 

 (E. S. R., 36, p. 316), and for which no substitute could be found, the authors 

 have modified the procedure for nitrogen determination by direct nesslerization. 

 The material used in the procedure is a synthetic mineral, an " aluminate 

 silicate," which possesses the peculiar absorptive properties characteristic of 

 some natural zeolites. The crude product is sold under the trade name " per- 

 mutit." 



The modified procedure is as follows : Two gm. of the powder is transferred 

 to a 200-cc. volumetric flask, 5 cc. of water added and, with an Ostwald pipette, 

 1 or 2 cc. of undiluted or, with a 5-cc. pipette, 5 cc. of diluted urine introduced. 

 The added sample is rinsed down with a little water and the mixture gently 

 but continuously shaken for five minutes. The powder is rinsed to the bottom 

 of the flask with water, and the supernatant liquid decanted. Water is added 

 once more and decanted. A little water is now added to the powder, 5 cc. 

 of 10 per cent sodium hydroxid introduced, the liquid agitated, and water added 

 until the flask is about three-fourths full. It is then shaken for a few seconds, 

 10 cc. of Nessler's reagent added, the liquid thoroughly mixed, and allowed to 

 stand for 10 minutes or as much longer as may be convenient. It is then filled 

 to the mark with water, mixed, and compared with the standard in the 

 colorimeter. 



Experimental data submitted indicate the accuracy of the method. 



A note on certain chemical changes in shucked oysters under refrigera- 

 tion, and methods of detecting these changes, E. D. Clark and L. H. Almy 

 (Jour. Biol. Chem., 29 (1917), No. 2, pp. XXIII, XZ/y).— Preliminary experi- 

 ments showed that freshly shucked oysters standing at temperatures above 

 the freezing point yielded regularly increasing percentages of ammoniacal nitro- 

 gen by aeration, amino-acid nitrogen, and reducing substances. 



Larger scale studies were made to simulate commercial practices in the 

 handling and transporting of oysters, in which samples were held at different 

 temperatures for various periods of time up to 15 days. During storage the 

 ammoniacal nitrogen showed the most marked increases, but the low tempera- 

 ture of 34° F. had a great inhibiting effect on the production of ammonia. 

 Amino-acid nitrogen and a reducing substance, which is indicated as probably 

 being sugar, did not show increases of the same magnitude as ammonia. 



