ANIMAL CHEMISTRY LECTURE VI. 



of oxalic or 2 -carbon, and of mesoxalic or 3 -carbon, hydrogenised 

 products; and that the majority of these products, like their ori- 

 ginal acids, are capable of forming mon-ureides by an elimination 

 of one atom, and other mon-ureides by an elimination of two 

 atoms of water ; and, further, that many of these mon-ureides 

 are capable of forming di-ureides by a further elimination of one 

 atom, and other di-ureides by a further elimination of two atoms 

 of water, we are no longer surprised at the great number and 

 variety of known compounds belonging to the uric acid group, 

 and shall not be surprised at the discovery of very many more. 

 The most important of those already known are included in the 

 following table. It is divided perpendicularly into three columns 

 of an-ureides, mon-ureides, and di-ureides ; and horizontally into 

 three layers of carbonic, oxalic, and mesoxalic products. The 

 compounds connected by means of dotted lines differ in composi- 

 tion from one another by an excess or deficit of one atom of urea 

 minus one atom of water ; while those standing on the same level 

 in the adjoining columns and unconnected by dotted lines, differ 

 from one another by an excess or deficit of one atom of urea 

 minus two atoms of water. 



An-ureides Mon-ureidea 



CH 4 Methylic C 2 N 2 H 6 Methyl-urea 



CH 3 3 Carbonic C 2 N 2 H 4 3 Allophanic 



Di-ureides 



C 3 N 2 H 6 Z Acet-urea 

 ''C 3 N 2 H 6 3 Hydautoic 



C 4 N 4 H 6 2 Glycoluril 

 ./' C 4 N 4 H 6 3 Allantoine 



