AGRICULTURAL CHEMISTRY. 9 



A iiart Qf the extract was then aciditied with acetic* acitl, tlie solution liltered, 

 ami nitrate precipitated with the nitron solution. 



The method was compared with other standard methods of determining nitric 

 acid, such as the Schloesiny; and the Schulze-Tiemann methods, under varying 

 conditions. The materials examined included compost earth, field soils, and 

 nuistard, as already stated. The results show that the method will very accu- 

 rately determine 2 to 3 mg. of nitrate nitrogen in 100 gm. of soil. In case of 

 !-oils containing less than this amount of nitrate it is not possible to make 

 accurate determinations on account of the fact that the repeated extraction 

 necessary and the greater concentration required result in increase of sub- 

 stances in the solution which prevent the crystallization of the nitron nitrate. 

 Substances which similarly interfere with the crystallization occur when soil 

 extracts are sterilized by heat. The difficulty due to these substances can be 

 removed by repeatedly adding hydrogen peroxid to the extract during evapora- 

 tion and by heating the concentrated extract with hydrogen peroxid in boiling 

 water for hours until the color is destroyed. The determinations of nitrate 

 in mustai"d indicate that the results heretofore obtained by other methods of 

 determining nitrates in plants are often too high. 



The determination of ammonia in water, A. Eonchese (Jour. Fhurm. ct 

 Chiin., 6. scr., 27 (7.908). No. 5, pp. 231-235; Bui. Soc. Chim. France, Jf. ser., 3 

 (HWH), Xo. 6, pp. 362-366). — ^The author describes an adaptation of his for- 

 maldehyde method ( E. S. II.. 15), p. 407) to the determination of small amounts 

 of anmionia in waters. He reports.tests with water containing varying amounts 

 of anunonia from which lie concludes tha.t the method is as exact as the more 

 sensitive methods of determining ammonia in water, as, for example, that of 

 Buisson. 



A method for the determination of very small amounts of carbon, espe- 

 cially the carbon of organic substances, in water, N. Popowsky (Arch. Hi/g., 

 65 {1908), A'O. 1, pp. 1-16, pgs. 2). — The method with which this article deals 

 is an adaptation of the wet combustion method perfected by Scholz in which 

 the organic matter is converted to carbon dioxid by boiling with potassium 

 bichromate and sulphuric acid. The carbon dioxid is measured by the decolor- 

 ization of sodium-carbonate solution containing phenolphthalein. the carbon 

 dioxid converting the carbonate to bicarbonate and thus destroying the color. 



A new reaction for protein, B. Bardach (ZtscJir. Phy.siol. CJicin., 5) (1908), 

 No. -'i, pp. 355-358). — The presence of albumin hinders the formation of iodo- 

 form from iodin or iodid of potassium and acetone. The author studied the 

 reaction with a number of different proteids and concludes that it not only 

 may be useful for the detection of protein but also may be of value in judging 

 of the nature of the proteid present. 



Chemistry of flesh. Further studies on the application of Folin's creatin 

 and creatinin method to meats and meat extracts, A. D. Emmett and H. S. 

 (;KI^■nLEV {-Jour. Biol. ('hem.. 3 {1901), No. 6. pp. .'i9l-516). — On the basis of 

 an extended chemical study of meat extracts and meats, conclusions were 

 drawn regarding the applicability to such products of the Folin method of 

 determining creatinin and creatin, and suggestions are made regarding details 

 of manipulation, etc. 



The authors conclude " that the Folin method when properly modified is 

 as ai)plicable to meat extracts and meats as it is to urine," and that it has 

 given reliable and concordant results in their experience. 



Concerning' Liebig^'s meat extract. III. Kutscher (ZcntbJ. I'lii/sioL, 21 

 (1907), No. 18. pp. 5Sii, .7<s'7).— A saturated alcoholic solution of cadmium chlorid 

 has proved a useful reagent in the study of meat extract bases. 



