CHEMISTRY OF THE LEUCOMAINES. 



319 



hypoxanthine, and cannot be said to be the result of direct 

 experimenta.! evidence. 



NH— C — NH N = C — NH 



CO 



I 

 NH— C 



CO 



I I 



CO— NH 



Uttic Acid, 



C5H,N,03 



CO 



I 

 NH— C CO 



II I 

 CH— NH 



Xanthine, 



C,H,N,0, 



N=C — NH 



I 

 CH 



II i 

 N— C CO 



II I 

 CH— NH 



Hypoxanthine. 



C,H,N,0 



N = C — NH 



I 

 CO 



i 



NH— C C=NH 



II I. 

 CH— NH 



Guanine. 



C.H,N,0 



N=C — NH 



I 

 CH 



N— C 



C=NH 



II I 



,<3H— NH 



C,H,N, 



Heteroxanthine, CjHjN^Oa, is a ne,wba8e which was 

 isolated from the urine in 1884 by Salomon. In its 

 composition it is methyl-xanthine, and is intermediate 

 between xanthine and paraxanthine or dimethyl-xanthine- 

 It occurs in the urine of man and of the dog; in about the 

 same amount as paraxanthine, and the method for its isola- 

 tion will be found under the description of that base. It 

 is a remarkable fact that this base occurs in dog's urine 

 unaccompanied by paraxanthine, and the same seems to 

 hold true for the urine of leucocytheemic persons. Salomon 

 examined the liver and muscles of a dog, but was unable 

 to obtain any heteroxanthine or paraxanthine, and the total 

 amount of xanthine bodies present was about normal. 

 Hence, he is inclined to think that these two bases may 

 possibly have their origin in the kidney. Unlike the other 

 xanthine bodies, heteroxanthine has not as yet been isolated 



