304 EXPEEIMENT STATION RECORD. 



stopper is placed in position and the slight air volume left in the bottle dis- 

 placed by water from the dropping funnel. The outlet tube is then closed, 

 whereupon the nitric oxid gas formed by decomposition of the nitrous acid fills 

 the upper part of the bottle, forcing the solution back into the funnel. When 

 from 5 to 10 cc. of gas are thus gathered, which requires but a few seconds, the 

 outlet is opened and the gas driven out again, washing out the remaining traces 

 of air. This is repeated to make absolutely certain that no air remains; then 

 the outlet is closed until a gas space of from 15 to 18 cc. has formed. The stop- 

 cock of the dropping funnel is then closed and the outlet connected with a gas 

 burette. The amino solution is run in from the 10 cc. burette, and the bottle 

 shaken at short intervals to hasten the evolution of gas. The latter is continued 

 until oO to 40 cc. more gas than the volume of nitrogen expected is in the gas 

 burette. The cock of the droi)ping funnel is then oi)ened, and all the gas from 

 the bottle and outlet tube displaced into the gas burette. This mixture of nitric 

 oxid and nitrogen is now run into a Hempel pipette containing a 5 per cent 

 potassium permanganate — 2.5 per cent potassium hydroxid solution, which 

 absorbs the nitrous oxid. The pure nitrogen is then measured in the burette." 



Alanin, valin, leucin, glycocoll, aspartic acid, glutaminic acid, phenylalanin, 

 serin, oxyprolin, tyrosin, ai'ginin, histidin, tryptophan, and guanin yield one 

 molecule each of nitrogen. Lysin yields 2 molecules of nitrogen. Prolin, being 

 an imino substance, does not react at all. Guanidin and its derivatives also fail 

 entirely to react. 



The method is expected to be of value for rapid analysis in identifying the 

 amino acids, for the estimation of the amount of amino nitrogen in unknown 

 substances, and in mixtures such as hydrolyzed protein. It has also been made 

 the basis of a quantitative estimation of the amino acids in urine. The urea 

 is first changed to ammonia by the action of sulphuric acid in an autoclave at 

 175°, the anmionia distilled off after the addition of calcium oxid. and the 

 amino nitrogen determined in the filtrate. It is suggested that this method will 

 be of value in indicating conditions where physiological oxidation of protein 

 nitrogen is incomitlete. 



A new reaction for proteids, W. Arnold (Abs. in Chcm. Zfg., 3Jf (1910), No. 

 38, pp. 332, 333). — A series of animal proteids gave a characteristic reaction 

 with sodium nitroprussid and ammonia, and which was not found to be due to 

 a splitting off of alkali sulphids. 



The test is conduc-ted as follows : To from 1 to 2 cc. of an aqueous solution 

 of the proteid is added from 2 to 4 drops of a 4 per cent sodium nitroprussid 

 solution and then a few drops of ammonia. In the presence of certain jn-oteids 

 an intense purple-red coloration will ensue. 



Hydrolysis of protein, M. Pfannl (Monatsh. Chcm., 31 (1910), No. 1, pp. 

 81-85). — Comparative tests made between the usual Fischer method and 

 Przibi'am's alcohol-hydrochloric acid method yielded with fibroin 33.8 per cent 

 glycocoll and 53.9 per cent volatile esters by the Fischer method, and 35.1 per 

 cent glycocoll and 5T.S per cent volatile esters by the Przibram method. With 

 gelatin the Przibram method yielded 10.8 per cent glycocoll and 3G.7 per cent 

 A'Olatile esters. 



A modification of Fischer's ester method, B. O. Pribram (Monatsh. Chcm., 

 31 (I'JIO), No. 1, pp. .51-5 'i). — As a possibility exists of resai)onification taking 

 place during the salting out process with sodium carbonate, as proposed by 

 Fischer, or with barium oxid as suggested by Levenne, the author proposes to 

 libei'ate the ester by means of dry ammonia. 



Casein peptones containing' phosphorus, M. Dietrich (Biochcm. Ztschr., 

 22 (1909), No. 1-2, pp. 120-130; abs. in Milchiv. Zcntbl., 6 (1910), No. 1, pp. 

 37, 38; Jour. Chem. Soc. [London], 98 (1910),No. 567, I, p. 82).— The calcium 



