192 XANTHINE. 



crystals of a compound of xanthine and ammonia will 

 be formed. 



7. Dissolve xanthine in hot hydrochloric acid. 

 When cool add platinic chloride; a yellow crystalline 

 precipitate of a double salt will ensue. 



8. To a dilute solution of xanthine in nitric acid, 

 add silver nitrate ; no precipitate will be produced (see 

 hypoxanthine). 



9. Xanthine is soluble in concentrated sulphuric 

 acid, and the solution is not precipitated by water. 



10. To a solution of xanthine in water add mercuric 

 chloride or cupric acetate ; a precipitate, white in the 

 first case, green in the second, will be formed. 



11. Dissolve a very little sodium in mercury, and 

 place in an aqueous solution of xanthine ; the latter 

 will be gradually reduced to hypoxanthine. 



