456 CEEMISTBY OF THE LEUGOMAJNS. 



sulphid, and the aqueous solution, filtered while boiling hot, yields a 

 deposit of a sulphur yellow powder of pseudoxanthin. Thus, by the 

 use of alcohol, ether, and water, Gautier, according to his statement, 

 has succeeded in obtaining a sharp separation between these bases. 

 The importance of the subject is such as to require not only confir- 

 mation of the results arrived at by Gautier, but also a more detailed 

 and exact study of the chemical and physiological behavior of these 

 bodies. 



The following method was employed by Gautier and Landi in 

 1892 in their study of the changes in meat. The meat extract was 

 concentrated in a vacuum to one-eighth its volume, then cooled, 

 precipitated with neutral lead acetate, filtered, and after washing the 

 precipitate, the filtrate was again concentrated to one-half its volume, 

 and the lead removed by hydrogen sulphid. The filtrate was again 

 concentrated to one-half its bulk and dialyzed. The bases are pres- 

 ent in the dialysate. The dialyzed portion therefore was concen- 

 trated, acidulated with nitric acid, and precipitated with phospho- 

 molybdic acid. The precipitate is collected and washed at once with 

 very dilute nitric acid, then with water. It is then boiled with 

 neutral lead acetate ; the bases and the greater part of the xanthin 

 and carnin pass into solution. After removal of the lead, the fil- 

 trate is evaporated in a vacuum, then extracted with alcohol. The 

 residue is examined for : 



Bases A. — It is treated with dilute ammonia ; this dissolves xan- 

 thin, hypoxanthin, guanin, carnin, etc., whereas creatin, etc., are in- 

 soluble. The ammonia is allowed to evaporate, and hence adenin 

 and guanin separate out. Hypoxanthin and xanthin remain in 

 solution. 



Bases B. — The alcoholic filtrate from above residue is neutralized, 

 concentrated, and treated with mercuric chlorid. The mercury 

 precipitate is washed, decomposed with hydrogen sulphid, the solu- 

 tion filtered, and the filtrate is precipitated with copper acetate : 



1. In the cold — acids of the carbopyridic series, which are crys- 

 talline and give crystalline platinochlorids. 



2. In boiling solution — xanthin bases. 



3. The portion not precipitated by cold or hot copper acetate is 

 the most important. The copper is removed with hydrogen sulphid, 

 the filtrate evaporated to dryness, and extracted with alcohol — 

 guanin, creatin, neurin, chlorin, butylenediamin, etc., neuridin, 

 ethylenediamin ; hydropyridin bases and homologues, and bases that 

 give pyrrol on distillation with lime; all are very poisonous. 



Bases C. — The mercuric chlorid filtrate is concentrated to drive 

 off the alcohol and the mercury removed with hydrogen sulphid. 

 Lead acetate is added, the liquid filtered, and after removal of the 

 lead is evaporated to dryness and extracted with dilute alcohol — 

 the residue was creatin ; the filtrate contained oxy-ethylenamin. 



