TRANSACTIONS OF THE SECTIONS. 39 
of a peculiar nature, on which account they come more within the 
range of chemical investigation than any other bodies of animal 
origin. Prout’s masterly analysis has long since removed every doubt 
respecting the composition of urea, and the extraordinary, and, to some 
extent inexplicable, production of this substance without the assistance 
of the vital functions, for which we are indebted to Wohler, must be 
considered one of the discoveries with which a new era in science has 
commenced. Wohler observed, that when cyanic acid is made to 
combine with ammonia, the product is urea; and he and I have, in 
a set of experiments which we made together, proved that these 
two bodies, when first combined, form cyanate of ammonia, a salt 
analogous to every other ammonia-salt; that is to say, the base can be 
replaced by other bases, and the acid by other acids; but that a few 
minutes after the combination has taken place, all these properties 
disappear. We can no longer detect either ammonia or cyanic acid; 
a new substance has been formed, entirely different from every other 
chemical compound. To follow out the characters of urea would here 
be quite out of place; it was however necessary to allude to it from 
its intimate relation to uric acid. 
“ The elementary composition of uric acid has also been established 
beyond a doubt. We are certain that it may be expressed by the 
formula C,, N,H,O,;. We know, also, that this acid combines with 
‘the different bases, and forms salts. Inorganic chemistry is satisfied 
with the determination of these properties; but it must be evident 
that the formula can give us no idea of the manner in which the 
elements are united together to form the substance. If we admit the 
principle that no ternary or quaternary compound can be formed 
except by the union of a binary compound with an element, or of two 
binary compounds with one another, it is clear that any further in- 
vestigation of uric acid must be carried on with the intention of dis- 
covering the compound elements into which it may be resolved. 
“ This investigation, which promised to yield the most important 
results both for medicine and chemistry, Professor Wohler and I 
determined to undertake together. In medicine, it was evident that 
we might have some new method of destroying calculi in the human 
bladder without the application of external force. In chemistry, the 
most interesting discoveries were also to be expected, as we had not 
the slightest doubt that urea, xanthic acid, cystic oxide, oxalic acid 
(which last substance is well known to constitute frequently an ingre- 
dient in urinary calculi), that all these bodies are produced by the 
decomposition of one single substance, and that substance uric acid. 
“ Our analytical investigations of these various bodies have not yet 
made sufficient progress to enable me to communicate them here. My 
intention at present is, to point out the plan which we followed in our 
attempts to decompose uric acid into its proximate elements, and the 
singular results which we obtained. But, before proceeding to do so, I 
wish to notice a very remarkable compound, which will, I think, serve 
greatly to illustrate the subject we are at present occupied with. 
