MESOXALJC MON-UREIDES. 137 



convertible by successive hydrogenation into bromobarbituric, 

 and barbituric acid, which last serves as a sort of nucleus in 

 the following series of compounds : 



Mesoxalic Mon-ureides 



C 4 N 2 H a (HO) a 3 Alloxanic. 



C 4 N a H a (Br a )0 3 Dibromobarbituric, 



C 4 N a H 4 3 Barbituric. 



C 4 N a H 3 (Br)0 3 Bromobarbituric. 



C 4 N 2 H 3 (HO)0 3 Dialuric. 



C 4 N 2 H 3 (H a N)0 3 Uramile. 



Qtiyi^H^SOjJOj Thionuric. 



C 4 N 2 H 3 (NO)0 3 Violuric. 



C 4 N 2 H 3 (NO a )0 3 Dilituric. 



C 8 N 4 H 6 (N a 3 )0 6 Violantine. 



The last body on the list namely, violantine seems to be not 

 a diamerone or residuary, but a completed compound of the vic- 

 luric and dilituric acids. It is observable that the mutual rela- 

 tionship of barbituric acid, dialuric acid, and uramile in this 

 subs-group is strictly parallel to that of lantanuric acid, oxaluric 

 acid, and oxaluramide in the preceding one. Moreover, the 

 malonic and barbituric acids are homologous with the oxalic and 

 parabanic acids respectively ; or, in other words, the most oxidised 

 of known 2-carbon uric acid products are homologically the re- 

 presentatives of the least oxidised 3 -carbon products thus, 



C a H 2 4 Oxalic C 3 N 2 H 2 3 Parabanic 



C 3 H 4 4 Malonic C 4 N,H 4 3 Barbituric; 



although from another point of view they correspond more nearly 

 with mesoxalic acid and alloxan, as I have already remarked. 



(145.) The relationship subsisting between the three mesoxal- 

 di-ureides, though long suspected from the similarity of their 

 formulae hypoxanthine C 5 N 4 H 4 O, xanthine C 5 N 4 H 4 2 , and uric 

 acid C 5 N 4 H 4 O 3 has but very recently received an experimental 

 demonstration at the hands of Strecker and Kheineck. With the 

 first of these bodies, or hypoxanthine, originally found by 

 Scheerer inhuman and bovine splenic juices, the so-called sarcine, 



