576 MUSCLES. 



tion of creatine in water is not precipitated by basic lead acetate, but 

 gives a white, flaky precipitate with mercurous nitrate if the acid reac- 

 tion is neutralized. When boiled for an hour with dilute hydrochloric 

 acid, creatine is converted into creatinine, and may be identified by its 

 reactions. On boiling with formaldehyde it can be transformed into 

 dioxymethylenecreatinine, which crystallizes readily (JAFFE l ). 



The preparation and detection of creatine is best accomplished by the 

 following method of NEUBAUER, 2 which was first used in the preparation 

 of creatine from muscles: Finely cut meat is extracted with an equal 

 weight of water at 50-55 C. for 10-15 minutes, pressed, and extracted 

 again with water. The proteins are removed from the united extracts 

 so far as possible by coagulation at boiling heat, the filtrate precipitated 

 by the careful addition of basic lead acetate, the lead removed from this 

 filtrate by H^S, and the solution then carefully concentrated to a small 

 volume. The creatine, which crystallizes in a few days, is collected on a 

 filter, washed with alcohol of 88 per cent, and purified, when necessary, 

 by recrystallization. In the preparation of large quantities of creatine 

 we can especially start with meat extracts. The quantitative estimation 

 of creatine is performed by transforming it into creatinine (see Chapter 

 XIV). 



Carnosine, CgHuN^a, is a base first isolated by GULEWITSCH and 

 AMIRADZIBI from meat extracts and which subsequently was also pre- 

 pared directly from meat. The quantity seems to be relatively consider- 

 able, as according to the above-mentioned determination of v. FURTH 

 and SCHWARZ, the carnosine fraction from the horse and dog muscles 

 was just as large or indeed greater than the creatine-creatinine fraction 

 of the extractive nitrogen. KRIMBERG found 1.3 p. m. and SKWcmzow, 3 

 1.76 p. m. (as nitrate) in fresh meat. 



Carnosine, which according to GULEWITSCH is identical with the base 

 ignotine isolated from meat extracts by KUTSCHER while both bases are 

 isomeric bodies according to KuTSCHER, 4 is a histidine derivative accord- 

 ing to GULEWITSCH which on cleavage yields /3-alanine besides histidine. 



Carnosine is a base readily soluble in water, which is precipitated 

 as stellar warts of short delicate needles from the concentrated watery 

 solution by the addition of alcohol. The specific rotation for the light 

 X = 546 is according to GULEWITSCH in watery solution where c = 12.925 

 per cent and 20.1 C. = +25.3. The base is precipitated by phospho- 



1 Ber. d. d. Chem. Gesellsch., 35. 



2 Zeitschr. f. analyt. Chem., 2 and 6. 



3 Gulewitsch and Amiradiibi, Zeitschr. f. physiol. Chem., 30; Gulewitsch, ibid., 

 50, 51, 52 and 73; Krimberg. ibid., 48; Skworzow, ibid., 68. 



4 Gulewitsch and Amirad&bi, Zeitschr. f. physiol. Chem., 30; Gulewitsch, ibid., 50, 

 61, 52 and 73; Krimberg, ibid., 68; Skworzow, ibid., 68; Kutscher, ibid., 50, 51. 



