CREATINE A3TD CBEATININE. 205 



tissue, and brain. 1 Scherer has demonstrated the presence 

 of creatine in the amniotic fluid. 8 By certain chemical 

 manipulations, both creatine and creatinine may be changed 

 into urea ; and the fact that these substances are now known 

 to be constant constituents of the urine leaves no doubt 

 that they are to be classed among the excrementitious prin- 

 ciples. Chevreul, who first discovered creatine in the ex- 

 tract of muscular tissue, regarded it as one of the nutri- 

 tive principles of meat ; * but the subsequent researches of 

 Heintz, 4 Liebig, 5 and others, who found it in the urine, re- 

 vealed its true character. Verdeil and Marcet e have since 

 found both creatine and creatinine in the blood ; and these 

 principles are now generally regarded as excrementitious 

 matters, taken from the tissues by the blood, to be eliminated 

 by the kidneys. 



Creatine has a bitter taste, is quite soluble in cold water 

 (one part in seventy-five), and is much more soluble in hot 

 water, from which it separates in a crystalline form on cool- 

 ing. It is but slightly soluble in alcohol, and is insoluble in 

 ether. A watery solution of creatine is neutral. It does 

 not readily form combinations as a base ; but it has lately 

 been made to form crystalline compounds with some of the 

 strong mineral acids, the nitric, hydrochloric and sulphu- 

 ric. 7 According to Neubauer and Yogel, when boiled for 

 a long time with baryta, it is changed into urea and sar- 



1 You, Ueber das Verhdten des Kreatins, Kreatinins und Harnstoffs im Thier- 

 korper. Zeitechrift fur Biologie, Miinchen, 1868, Bd.iv., S. 78. 



2 SCHERER, Analyse d'un liquide amniotique. Annuaire de chimie, Paris, 1850, 

 p. 576. 



3 CHEVREUL, Uhtersuchungen uber die chemische Zusammensdzung der Fleisch- 

 briihe. Journal fur praktische Chemie, Leipzig, 1835, Bd. vi., S. 120, et seq. 



4 HEINTZ, Ueber eine nene Sdure im menschlichen Ham. Annalen der Physik 

 und Chemie, Leipzig, 1844, Bd. Ixii., S. 602. 



5 LIEBIG, Recherches de chimie medicate. Comptes rendus, Paris, 1847, tome 

 xxiv., p. 69, et seq. 



6 ROBIN ET YERDEIL, Tratte de chimie anatomique, Paris, 1853, tome ii., pp. 

 480, 489. 



7 XEUBAUER AND VOGEL, op tit., p. 17. 



