W. Gibbs on Uric Acid. 291 
H.. NH. 
Its formation from urea and relations to cyanic acid are thus 
clearly shown, No higher terms in this series are known, but 
we ought to obtain hereafter triuret, tetruret, &c., correspond- 
ing to tricyanic, tetracyanic acids, &c., just as biuret corres- 
ponds to dicyanic acid. Thus triuret would be 
N=€—Ho 
3 H N=H,, 
_ and might perhaps be formed by heating together one molecule 
of dicyanic acid, or two of cyanic acid, and one of urea. 
_Guanidin and methyluramin appear also to belong to the 
ro cyanic acid type, their formulas being taken respec- 
ay as 
NH=€=(NH,), and N(€H,)=€=(NH,), 
Guanidin. Methyluramin. 
: Dieyanic acid upon my view forms the first or completely 
_ Uultrogenized term of the following series : 
N=€-Ho @=€—Ho 6 =6—Ho H,=—€—Ho H,=—¢€-H 
N=€-Ho O@=€—Ho H,=6—Ho H,=t-Ho H,=€-H 
: Dieyanic acid.  Oxxalic acid. Glycolic acid. Glycol. Hydrocarbon. 
___ If we replace hydroxyl in dicyanic acid by hydrogen and its 
Watives, we have the following possible compounds : 
Hae —Ho N=€-H @—€—Ho ~~ —H 
N=€_H N=6-H 6—6_H 6—¢-H 
__ Unknown. © Unknown. Glyoxalic acid. Glyoxal. 
oe these I may be permitted to add the following which, 
wide with the exception of glycocoll, not derivatives of uric 
NH =€~Ho N(€H,)=€—Ho NH =€—(€,H,®) 
He=€— Ho H,=€—-Ho  H,=€-— Ho 
ven ly cocoll, Sarkosin. Hippurie acid. 
‘J-€=NH (NH )-C=NHNH -C=[NH NH -—€=NH 
: | ’ 1 j | 
NH “S—Ho N(€H,)-6—Ho NH -€\ N(€H,)-€Nq 
Qz’-Ho §=-H, =€-Ho = H, =6/ 
yee aaa Kreatin. Glycocyamidin. Kreatinin. 
st hag or cyanuric acid forms the first term of the follow- 
“posh sear ada il: 
