On Gravelly and Calculous Cona-eiions. 203 



soluble in very different and opposite kinds of menstrua: 

 as ;ilbO a letter from Dr. Saunders to Dr. Percival, of Man- 

 chester, published in the third volume of Percival's Philo- 

 sophical and Experimental Essays, in 1776, detailing several 

 experiments ; from which he fairly concludes that the doc- 

 tor's enthusiastic hope, of dissolving all calculi in a solution 

 of carbonic acid, must prove groundless, from the very dif- 

 ferent nature of their component parts, as ascertained by 

 his own cxpcnments. This was placed beyond further 

 doubt by our own learned and ingenious professor Mr. 

 William Higgins, who, in an analysis of a calculus, of 

 "which he gives an account in his Comparative View of 

 the Phlogistic and Antiphlogistic Theories, (a work of sin- 

 gular merit for that period, to which we will afterwards 

 refer.) and published so far back as 1789, enumerates the 

 iTiaiiy various substances contained in one specimen only. 

 The researches of Austin, Lane, and Brugnatelli, led to 

 similar results. But to the learned and accurate Dr. Wol- 

 laston we stand indebted for the Hrst clear and distinct dis- 

 crmiination of the component parts of these substances. 

 In a paper read to tlie Royal Society in the year 1 797, 

 which would not discredit either a Bergman or a Klaproth, 

 he has most accurately demonstrated, both analvticaily an4 

 fiynthetically, the component parts of three distinct species 

 of calculi ; namely, the fusible, as he lerms it, or the ammo- 

 liiaco-magnesian phosphate of Fourcroy ; the mulberry, or 

 oxalate of lime kind ; and bone earth calculus, or phos- 

 phate of lime, which, with the uric, well known to us 

 since the time of Scheele, left us then acquainted with the 

 four species of calculi of most frequent occurrence. Under 

 these circumstances I cannot help expressing my surprise 

 at finding M. Fourcroy still assuming the merit of the dis- 

 covery of all the different component parts of calculi, the 

 uric acid and phosphate of lime excepted. This circum- 

 stance must appear the more unaccountable, when we con- 

 sider that the communication of Dr. Wollaston's experi- 

 ments was through the medium of the Transactions of the 

 Royal Society for 1797. Finally, M. Fourcroy, to whom 

 Europe stands not a little indebted for the present general 

 diffusion of chemical knowledge, and to whom the medical 

 profession owe the greatest obligations for his unremitted 

 application to animal chemistry, has, in conjunction with 

 Vauquelin, given us the result of his researches upon five 

 hundred calculi ; from which it appears that they contain 

 Iht: sevcji following ingredients : 



1. Uric acid. 



2. Urate of ammonia. 



3. Phosphate 



