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XXXI. Further Contributions to the Chemical History of the 

 Products of the Decomposition of Uric Acid. By William 

 Gregory, M.D., F.R.S.E* 



TN 1840 I described, at the Glasgow Meeting of the British 

 -*- Association, an improved and very productive method of 

 preparing alloxan, murexide, &c. ; and I showed, from the 

 occurrence of urea among the products of the action of hy- 

 permanganate of potash on uric acid, that Liebig and Wohler's 

 view, according to which urea pre-exists in uric acid, must be 

 admitted, in the present state of our knowledge, as well- 

 founded ; thus giving additional probability to the supposition 

 of the existence of the acid supposed by them to be present 

 in uric acid, combined with urea, and called, hypothetically, 

 urilic acid = C 8 N 2 4 . 



Since that period I have been frequently occupied with the 

 subject of uric acid. In 1841, Professor Liebig having en- 

 trusted to me the treatment of upwards of 2 lbs. of urate of 

 ammonia, I extracted the uric acid from this, and converted 

 nearly the whole of it into alloxan, of which I obtained 1 ^ lb. 

 in large and absolutely pure crystals. This not only enabled 

 me to study the preparation of several of the other products, 

 but led me to economise as much as possible the very abun- 

 dant mother-liquid of the alloxan, which contained a large 

 quantity of that substance, but so much mixed with nitrate of 

 ammonia and free nitric acid, that the alloxan could not be 

 purified by crystallization, even if the liquid could have been 

 concentrated by heat without decomposition. I shall now 

 state the results of my experiments, as far as these are to- 

 lerably ascertained. There is still much to be done, and se- 

 veral investigations are in an imperfect state in my laboratory. 

 As it may be some time however before I may be able to re- 

 turn to them, I think it right, in the mean time, to describe 

 the results hitherto obtained. , 



1. Alloxantine. 

 This compound is best obtained from the mother-liquid of 

 alloxan, as prepared according to my process f. The acid 

 solution is diluted with two or three parts of water, and a cur- 

 rent of sulphuretted hydrogen gas is passed through as long 

 as it produces any effect. Sulphur is first deposited, and sub- 

 sequently a large quantity of alloxantine. The mixed pre- 

 cipitate is drained, washed with a little cold water, and then 

 boiled with water, acidulated with hydrochloric acid, until all 



* Communicated by the Chemical Society j having been read November 

 7, 1843. 

 t See Turner's Chemistry, 7th edition. 



