British Association for the Advancement of Science. 41 



account they come more within the range of chemical investiga- 

 tion than any other bodies of animal origin. Front's masterly 

 analysis has long since removed every doubt respecting the com- 

 position of urea, and the extraordinary, and, to some extent, inex- 

 plicable, production of this substance without the assistance of the 

 vital functions, for which we are indebted to Wohler, must be con- 

 sidered 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 am- 

 monia, a salt analogous to every other ammoniac 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 form- 

 ed, entirely different from every other chemical compound. To 

 follow out the characters of urea, Avould here be quite out of 

 place : it was, however, necessary to allude to it from its intimate 

 relation to nitric acid. 



The elementary composition of uric acid has also been estab- 

 lished beyond a doubt. We are certain that it may be expressed 

 by the formula C N H O. We know also that this acid com- 



10 4 4 6 



bines with the different bases, and forms salts. Inorganic Chem- 

 istry is satisfied with the determination of these properties, but it 

 must be evident that this formula can give us no idea of the man- 

 ner in which the elements are united together to form this sub- 

 stance. If we admit the principle, that no ternary or quaternary 

 compomid can be formed, except by the union of a binary com- 

 pound with an element, or of two binary compounds with one 

 another, it is clear that any further investigation of uric acid must 

 be carried on with the intention of discovering the compound ele- 

 ments into which it may be resolved. 



This investigation, which promised to yield the most important 

 results, both for Medicine and Chemistry, Prof. Wohler and I de- 

 termined to undertake together. In Medicine, it was evident that 

 we might have some new method of destroying calculi in the hu- 

 man bladder, without the application of external force. In Chem- 

 istry, the most interesting discoveries were also to be expected, as 



YoL. XXXIY.— No. 1. 6 



