714 URINE. 



SALOMON. 1 It crystallizes beautifully in six-sided plates or in needles. The 

 sodium compound crystallizes in rectangular plates or prisms and, like the hetero- 

 xanthine-sodium compound, is insoluble in 33-per cent caustic-soda solution. 

 The sodium compound separates in a crystalline state on neutralizing its solution 

 in water. The chloride is readily soluble and is not decomposed by water. The 

 chloroplatinate crystallizes very beautifully. Mercuric chloride precipitates it 

 only when added in excess and after a long time. The silver-nitrate compound 

 separates as White silky crystals from hot nitric acid on cooling. It gives WEIDEL'S 

 reaction, but not the xanthine test, with nitric acid and alkali. 



Episarkine is the name given by BALKE to a purine body occurring in human 

 urine. The same body has been observed by SALOMON 2 in pigs' and dogs' urine, 

 as well as in urine in leucaemia. BALKE gives C4HN 8 as the probable formula 

 for episarkine. It is nearly insoluble in cold water, dissolves with difficulty in 

 hot water, but may be obtained therefrom as long fine needles. Episarkine does 

 not give the xanthine reaction with nitric acid, or WEIDEL'S reaction. With 

 hydrochloric acid and potassium chlorate it gives a white residue which turns 

 violet with ammonia. It does not form any insoluble sodium coimoound. The 

 silver compound is difficultly soluble in nitric acid. 



HN CO 



Epiguanine, C 6 H 7 N 6 0, 7-methylguanine, H 2 N.C C.N.CH 3 , was first pre- 



N C. 



pared from the urine by KRUGER. 3 It is crystalline and difficultly soluble in 

 hot water or ammonia. It crystallizes from a hot 33-per cent caustic-soda solu- 

 tion on cooling in broad shining crystals and dissolves readily in hydrochloric or 

 sulphuric acid. It gives a characteristic chloroplatinate crystallizing in six-sided 

 prisms. It is precipitated neither by basic lead acetate nor by basic lead ace- 

 tate and ammonia. Silver nitrate and ammonia give a gelatinous precipitate, 

 It responds to the xanthine test with nitric acid and alkali. It acts like episarkine 

 with WEIDEL'S test according to FISCHER. 



In preparing alloxuric bases from the urine, the fluid is supersaturated with 

 ammonia and precipitated by a silver-nitrate solution. The precipitate is then 

 decomposed with sulphuretted hydrogen. The boiling-hot filtrate is evaporated 

 to dryness and the dried residue treated with 3-per cent sulphuric acid. The 

 purine bases are dissolved, while the uric acid remains undissolved. This filtrate 

 is saturated with ammonia and precipitated by silver-nitrate solution. If instead 

 of precipitating with silver solution we desire to precipitate, according to KRUGER 

 and WULFF, with copper suboxide, the urine may be heated to boiling, and imme- 

 diately are added, successively, 100 cc. of a 50-per cent sodium-bisulphite solu- 

 tion and 100 cc. of a 12-per cent copper-sulphate solution for every liter of urine. 

 The thoroughly washed precipitate is decomposed with hydrochloric acid and 

 sulphuretted hydrogen. The uric acid remains in great part on the filter. Further 

 details in regard to the treatment of the solution of the hydrochloric-acid com- 

 pounds may be found in KRUGER and SALOMON. 4 



iThudichum, " Grundzuge d. anal. med. klin. Chemie " (Berlin, 1886); Salomon, 

 Arch. f. (Anat. u.) Physiol., 1882, and Ber. d. deutsch. chem. Gesellsch., 16 and 18. 



2 Balke, " Zur Kenntniss der Xanthinkorper " (Inaug.-Diss., Leipzig, 1893); Salo- 

 mon, Zeitschr. f. physiol. Chem., 18. 



3 Arch. f. (Anat. u.) Physiol., 1894; Kriiger and Salomon, Zeitschr. f. physiol. 

 Chem., 24 and 26. 



4 Zeitschr. f . physiol. Chem., 26, and also Hoppe-Seyler-Thierfelder's Handbuch, 

 8. Aufl., 188. 



