THE EXTRACTIVES OF MUSCLE. 



103 



well as iron. By means of baryta water, carnic acid (C 10 H 15 N 3 5 ) was 

 separated out from it. In muscle, this acid is combined with phosphorus 

 as phospho-carnic acid. Carnic acid itself is identical with antipeptone. 

 This discovery itself shows that our views concerning the hemi- 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 5 H 4 N 4 0. HN0 3 . 



c. Hypoxanthine hydrochloride, C-H 4 N 4 0. HC1. 



d. Xanthine silver nitrate, C 5 H 4 N 4 '0 AgN0 3 . 



e. Xanthine nitrate, C 5 H 4 N 4 2 . HN0 3 . 



/. Xanthine hydrochloride, C S H 4 N 4 2 HC1. 



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 30 H 41 N 9 15 ; oxylic acid, C 18 H 28 N 4 8 ; and various crystalline metallic 

 salts of these acids), and has devised a method for its estimation. 2 It 



1 Ztschr. /. physiol. Chem., Strassburg, 1896, Bd. xxii. S. 248. 



2 Balke and Ide, ibid., Bd. xxi. S. 380. 



