THE EXTRACTIVES OF MUSCLE. 103 
well as iron. By means of baryta water, carnic acid (C 10 l [^NjOs) was 
separated out from it. In muscle, this acid is combined with phosphorus 
as phospho-carnic acid. Carnic acid itself is identical with antvpejptone. 
'Hi is discovery itself shows that our views concerning the henii- and 
anti-products of digestive proteolysis will need revision. Carnic acid 
is a comparatively simple substance, of low molecular weight, and of 
acid reaction. It is free from sulphur, and gives most of the proteid 
Fig. 17. — Compounds of xanthine and hypoxanthine, by means of which these substances 
may be isolated and identified. — After Kiihne. 
a. Hypoxanthine silver nitrate, C 5 H 4 N 4 O.AgN0 3 . 
b. Hypoxanthine nitrate, C 3 H 4 N 4 0. HN0 3 . 
c. Hypoxanthine hydrochloride, C'-H 4 N 4 0. HC'l. 
d. Xanthine silver nitrate, C 5 H 4 N 4 0., AgNO a . 
e. Xanthine nitrate, C s H 4 N 4 2 . HN0 8 . 
/. Xanthine hydrochloride, C 5 H 4 N 4 0oHCl. 
tests; it does not give Millon's reaction. This discovery will no doubt 
form an important clue in the problem of proteid constitution. This 
announcement of Siegfried's has been fully confirmed by Balke, 1 
who has prepared many compounds and derivatives (oxycarnic acid, 
C., H 41 X a O 15 ; oxylic acid, C ls H, 8 N 4 8 ; and various crystalline metallic 
salts of these acids), and has devised a method for its estimation. 2 It 
1 Ztschr. f. physiol. Chem., Strassburg, 1896, Bd. xxii. S. 248. 
- Balke and Ide, ibid., Bd. xxi. S. 380. 
