Report of the Committee on Editing Tentative and Offical Methods of Analysis, the Association of Official Agricultural Chemists . under I,18, 21 or 23, and subtract the nitrogen thus obtained from the nitrogen in thefiltrate from the coagulable protein to obtain the nitrogen of the precipitatedprotein (proteoses and gelatin). 43 GELATIN.—TENTATIVE. Prepare a 50% solution of the sample, using hot water. Allow to cool and placein an ice box for 2 hours. If gelatin is present, the solution will set. The ratio of total creatinin to total nitrogen in a normal meat extract (1 : )assists in determ
Report of the Committee on Editing Tentative and Offical Methods of Analysis, the Association of Official Agricultural Chemists . under I,18, 21 or 23, and subtract the nitrogen thus obtained from the nitrogen in thefiltrate from the coagulable protein to obtain the nitrogen of the precipitatedprotein (proteoses and gelatin). 43 GELATIN.—TENTATIVE. Prepare a 50% solution of the sample, using hot water. Allow to cool and placein an ice box for 2 hours. If gelatin is present, the solution will set. The ratio of total creatinin to total nitrogen in a normal meat extract (1 : )assists in determining the presence of gelatin or gelatin derivatives. The ratio isdecreased when gelatin or gelatin derivatives are present in any considerableamount. 282 METHODS OF ANALYSIS [Chap. AMINO NITROGEN. Van Slyke Method^^.— Tentative. 44 REAGENTS. (a) Alkaline permanganate solution.—Dissolve 50 grams of potassium permanga-nate and 25 grams of potassium hydroxid in sufficient water to make 1 liter. (b) Sodium nitrite solution.—Dissolve 30 grams of sodium nitrite in sufficientwater to make 100 cc. (C) Glacial acetic FIG. 10. VAN SLYKE APPARATUS FOR THE DETERMINATION OF AMINO NITROGEN. {By courtesy of the Journal of Biological Chemisiry.) 45 APPARATUS. Employ the apparatus shown in Figs. 10 and 11, the former illustrating the man-ner in which the entire apparatus is arranged and the latter showing the details XXI] MEAT AND MEAT PRODUCTS 283 of the deaminizing bulb and connections. The Hempel gas pipette is filled withthe alkaline permanganate solution. 46 DETERMINATION. Fill with water the burette (F), the capillary tube leading to the Hempel pipetteand also the other capillary as far as c. Introduce into A sufficient glacial aceticacid to fill one fifth of D, the tube (A) being etched with a mark to measure this
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