CHEMICAL BASIS OF THE ANIMAL BODY. 1L'7 



large quantities in Liebig's 'extract of meat* which is the most 

 convenient source for its preparation l 



Liebig's extract is dissolved in four parts of warm water. To this 

 solution two volumes of 90 p. c. alcohol are added and the precipitate 

 is removed by tiltration. The filtrate, after concentration, is again 

 precipitated with four volumes of alcohol. The filtrate from this 

 second precipitate is finally concent rated, acidulated with sulphuric acid. 

 and extracted with r\ce of .-ther which dissolves out the sarcolactic 

 acid. On evaporating off the t-ther and dissolving the residue in 

 \\ater, the pure acid may he ohtained hy forming its zinc salt, which 

 i> puritied by ery>talli.-at ion and decomposed by sulphuretted hydrogen. 



F>r the method of detecting and separating this acid from urine see 

 Salkowski and Leube. 2 



Tin- /inc and r;il< iuni salts of sarcolactic acid are much more 

 soluble both in water and alcohol than are those <>f ethylidene- 

 lactic acid. 



xn,;-i>lii,'titte. Zn (C 8 H 6 O 3 )2 + 2H 2 O. Soluble in \~~~> 

 of water at 15 or 964 parts of boiling 98 p. c. alcohol. 



t '"Icium sarcolactate. Ca (C,H 6 O 3 )2 + 4H 2 O [ ? 4^ H 2 OJ. Solu- 

 ble in r_' 4 jiarts of cold water, soluble in all proportions in boiling 

 water or alcohol. 



The free acid is dextro-rotatory, but the true value of (a) D is 

 unknown owing to uncertainty as to the purity of the acid. The 

 salts on the other hand are all bjevo-rotatory. For the zinc salt, 

 when one part is dissolved in 18 of water (a) D = -7'6. 



FI-. :.' Xivc SM.-. 01. \CTATE. 

 (After Kulme.) 



FII. .'t CM i M M Svi:. -in \CTATE. 



(. \ftiT Klllllll' ) 



Both this acid and the juvcedinu one yield an intense yellow 

 rnlniuation when added to ail c.xtreniely dilute (almost colourless) 

 solution of ferric chloride. This reaction is sour-times useful. 3 



1 See Oamgee, Physiol. Chemist, ,,. V..1 i 1880. p. 361. 



// ,11 

 * Uffelmann, Arch.f. kl(n M-><l. Ud. x.\vi. (l^so). S 431. 



