190 Dr. Gregory on the Decomposition of Uric Acid. 



ferent salt, of a gelatinous aspect, which has not been further 

 examined. I have not examined those tabular crystals, nor, 

 indeed, have I as yet seen them ; but I have by other means 

 obtained a salt, the acid of which appears to be composed of 

 alloxan and sulphurous acid. 



To obtain this salt, dissolve alloxan in the smallest possible 

 quantity of cold water, and add to the solution a slight excess 

 of a saturated solution of sulphurous acid in water. Then 

 add, with care, caustic potash in solution till there is the 

 slightest possible alkaline reaction. There will be deposited 

 very soon, partly even at once, in the cold solution a salt in 

 hard brilliant crystals, which may easily be obtained, by re- 

 crystallization, of considerable size, and are very beautiful, 

 from their perfect whiteness, their transparency and brilliant 

 lustre. This new salt may be procured in any quantity and 

 with the utmost facility. I have not yet succeeded in isolating 

 the acid, but the analysis of the salt indicates that the acid 

 consists of two atoms of sulphurous acid and one of alloxan. 

 It thus differs from thionuric acid by the absence of 1 eq. am- 

 monia, and probably also in being monobasic, while thionuric 

 acid is bibasic. The analytical details concerning this new 

 acid, which I propose to call the alloxano-sulphurous, will 

 appear when I have completed my investigation of its pro- 

 perties. It is probable that the large tabular crystals above 

 mentioned, as obtained by Liebig and Wohler, are nothing 

 more than the alloxano-sulphurous acid in a free state. 



6. Alloxanic Acid. 



When pure alloxantine is dissolved in distilled water, and 

 the cold solution allowed to stand, it slowly loses the property 

 of giving a violet precipitate with barytic water, and finally 

 yields a white precipitate. 



The liquid is now acid, and if gently evaporated to dryness 

 yields crystals, which are very soluble both in water and al- 

 cohol, and which possess all the chemical characters of allox- 

 anic acid. Professor Liebig did me the favour to examine 

 these crystals as obtained by me, and considered them to be 

 alloxanic acid, as I had previously done. I did not consider 

 them pure enough for analysis, and besides their analysis 

 could throw little light on the subject, as the crystallized al- 

 loxanic acid has the same composition in 100 parts as anhy- 

 drous alloxan; and differs, therefore, from alloxantine only 

 by containing 1 eq. of hydrogen less. 



Should this observation be confirmed, it seems difficult to 

 account for the production of alloxanic acid in this experiment. 

 No other compound appears to be formed, and the change 



