ANIMAL ACIDS CONTAINING AZOTE. 



was rather important. He showed that when it was treated with 

 nitric acid, a considerable quantity of oxalic acid was formed.* 

 This throws some light upon the existence of oxalate of lime in 

 urinary calculi ; for Scheele had shown that uric acid is a con- 

 stant ingredient in urine. 



Gay-Lussac first attempted to analyse uric acid by means of 

 black oxide of copper. He measured the volumes of carbonic 

 acid and azotic gases evolved, and found them to each other as 

 69 : 31, or as 5 : 2-246.f This, as we shall see afterwards, con- 

 stitutes a tolerably near approximation to the truth. The pro- 

 perties of uric acid were farther investigated by Dr Henry, who 

 made it the subject of his thesis, when he took his medical degree 

 at Edinburgh in 1807. His experiments were revised and pub- 

 lished in an English dress in 18134 Berard subjected it to 

 analysis, and published the result in his thesis on the analysis of 

 animal substances, which he supported at Montpellier, when he 

 graduated in that University in 1817. In the same year an im- 

 portant paper by Dr Prout, on the nature and proximate princi- 

 ples of urine, was published in the eighth volume of the Medico- 

 Chirurgical Transactions. He gives an analysis of uric acid, re- 

 markable for the care and accuracy with which it was conducted. 

 Uric acid was again analyzed by Kodweiss in 1830,|| by Mitscher- 

 lich,1f and by Liebig** in 1834. 



Scheele had observed that when uric acid is distilled, an acid 

 substance sublimed, which he considered as analogous to succinic 

 acid. Dr Pearson obtained it also, and considered it as benzoic 

 acid. It was examined more in detail by Dr Henry, who con- 

 cluded from his experiments that it was a new acid united to 

 ammonia. The subject was taken up by Chevallier and Las- 

 saigne in 1820. ft These gentlemen examined its properties in 

 detail, showed its peculiar characters, subjected it to analysis, 

 and distinguished it by the name of pyruric acid. 



In the year 1838, a most important set of experiments on uric 

 acid, and the various new compounds which it is capable of yield- 



* Ann. de Chim. xxviii. 56. f Ibid. xcvi. 53. 



\ Memoirs of the Literary and Philosophical Society of Manchester, (2d Se - 

 ries), Vol. ii. 



Ann. de Chim. et de Phys. v. 292. || Poggendorf's Armalen, xix. 1. 



^f Ibid, xxxiii. 335. ** Annalen der Pharmacie, x. 47. 



ff Ann. de Chim. et de Phys. xiii. 158. 



