414 CHEMISTRY OF THE LEUCOMAINS. 



lead acetate, but is precipitated by the basic salt as a flocculent white 

 precipitate soluble in boiling water. On heating carnin decomposes 

 and takes fire, and at the same time gives off a peculiar odor. It 

 crystallizes with one molecule of water, which it loses at 100°— 110**. 



The hydrochlorid, CjHgNPj.HCl, forms pretty prisms (Kem- 

 merich), and decomposes on heating with concentrated hydrochloric 

 acid. 



The platinochlorid, CjHjNPj.HCl.PtCl^ , forms a fine, sandy, 

 golden-yellow powder. 



With silver nitrate carnin unites to form a white flocculent pre- 

 cipitate, insoluble in nitric acid or in ammonia hydrate. Its formula 

 corresponds to 2(CyH,AgNP3) + AgN03 . 



With copper solution and reducing agent it gives a yellow pre- 

 cipitate which on washing becomes grass-green (Balke). 



Carnin is not affected by prolonged boiling with concentrated 

 barium hydrate. Bromin water decomposes it with the evolution of 

 gas and the formation of hypoxanthin. This change takes place 

 according to the following equation : 



C^gNp, + 2Br = C^H^NP-HBr + CHjBr -|- CO, . 



A similar decomposition into hypoxanthin is brought about by the 

 action of nitric acid, though in this case oxalic acid and a yellow 

 body are formed. Because of this decomposition carnin cannot be 

 expected when Neubauer's method is used. When carnin is evapo- 

 rated with chlorin water containing a little nitric acid, the residue, 

 on contact with ammonia, gives a rose-red color (murexid test). This 

 is due, according to Weidel, to the formation of hypoxanthin, but it 

 has since been shown that the latter base does not give this reaction 

 which, however, is given by xanthin and its' derivatives. 



The constitution of carnin is not known. It is undoubtedly an 

 ester of hypoxanthin. The above decompositions may be taken to 

 indicate the presence of an acetic group in position 7 ; otherwise it 

 must be looked upon as a methyl carboxyl derivative of hypoxanthin. 



The physiological action of carnin has been examined somewhat 

 by Briicke, and according to him the base is not very poisonous. 

 The only effect observed, when taken internally, was a fluctuation 

 in the rate of the heart-beat, though even this was by no means 

 definite in its nature. 



Oarnosin, CjHj^NPj, is a new base isolated in 1900 by Gule- 

 witsch and Amiradzibi^ from Liebig's meat extract. It has not as 

 yet been studied very thoroughly and nothing definite can be said as 

 to its structure. The silver compounds show, however, a striking 

 resemblance to arginin. It may be looked upon as a di-methyl 



' Berkhte, 33, 1902. 



