CHAP. IX.] THE CONTRACTILE TISSUES. 327 



evaporated until, on cooling, crystals commence to separate. It is then 

 set aside for some days to crystallize. The liquid from which the 

 crystals have separated is then treated with twice or three times its 

 own volume of 88 per cent, alcohol, and the crystals which readily 

 fall from this mixture of mother liquor and spirit are collected 

 on a filter and, if necessary, weighed. They are at first yellow, 

 but are obtained perfectly colourless by recrystallizing. 



III. (Stadeler's process 1 ). Finely divided meat is digested on the 

 water-bath with twice its volume of alcohol. The insoluble matter is 

 pressed and the filtrate is heated on the water-bath so as to drive off 

 a great part of the alcohol. Solution of basic lead acetate is then 

 added and the process continued as in II. 



Pro erties Creatine crystallizes in the form of transparent, 



colourless, shining, oblique, rhombic columns, which 

 when heated to 100 C. lose their water of crystallization (12'17 p. 

 cent.) and become opaque. 



The crystals belong to the monoclinic system. Inclination of the clino- 

 diagonal to the principal axis 70 20'. Inclination of the faces oo P : co P 

 in the plane of the orthodiagonal and principal axis = 132 2' (nearly). Spe- 

 cific gravity of the crystals 1'35 to 1/34. 



Creatine is soluble in 74 parts of cold water at 18 C. : freely 

 soluble in hot water: slightly soluble in spirits of wine: but almost 

 insoluble in absolute alcohol and ether. One part of creatine requires 

 9400 parts of absolute alcohol at ordinary temperatures to dissolve it. 



Compounds Though solutions of creatine have a neutral reaction, 



the body is a weak base which, when dissolved in hydro- 

 chloric, sulphuric, and nitric acids, forms compounds which crystal- 

 lize well. The following are the formulae of these compounds : 



Hydrochlorate of Creatine C.H 9 N 3 O 2 . HC1 

 Sulphate C 4 H 9 N 3 2 .H 2 S0 4 



Nitrate C 4 H 9 N 3 O 2 . HN0 3 . 



A compound of mercury and creatine is formed in which two atoms 

 of hydrogen are replaced by a single atom of mercury (C 4 H 7 HgN 3 O 2 ). 



1 Stadeler, Journ. f. pract. Chem. Vol. 72, p. 25P. 



