URINARY CALCULI. 555 



amber. They consist of phosphate of lime tinged with the se- 

 cretion of the prostate gland. 



About the commencement of the present century Fourcroy 

 and Vauquelin announced their intention of making a rigid ana- 

 lysis of all the calculi which they could procure, and invited me- 

 dical men to send them specimens. In this manner they obtain- 

 ed and examined about 600 different calculi. They found the 

 same substances which Wollaston had described, and likewise 

 urate of ammonia, and in two calculi a quantity of silica. It is 

 remarkable that, though Dr Wollaston's experiments had been 

 published three years before, and in the Philosophical Transac- 

 tions, a copy of which is regularly transmitted to the Academy 

 of Sciences, of which Fourcroy was a member ; yet Fourcroy, 

 who drew up the account of the experiments, takes no notice 

 whatever of the previous labours of Wollaston, who had antici- 

 pated almost all the discoveries which they made respecting the 

 constitution of calculi.* 



In the year 1808,| Mr Brande examined the calculi in the 

 Hunterian Museum, at that time in the possession of Sir Everard 

 Home, but now the property of the University of Glasgow. He 

 informs us that he examined 150 calculi, and found their consti- 

 tution as follows : 



1 6 were composed of uric acid. 



46 of uric acid with a small portion of phosphates. 



66 of phosphates with a little uric acid. 



12 composed of phosphates entirely. 



5 of uric acid with the phosphates and nuclei of 



oxalate of lime. 



6 of oxalate of lime chiefly. 



150 



Mr Brande endeavours to prove that the urate of ammonia 

 found by Fourcroy and Vauquelin was only a mixture of uric 

 acid 'and sal-ammoniac. It is remarkable that, as far as my ob- 

 servations go, and I have examined the Hunterian collection of 

 calculi with considerable attention, it contains no calculus con- 

 sisting of urate of ammonia. But in the collection of the late 



* Fourcroy's papers appeared in various volumes of the Annales de Chimie, 

 and in his Systeme des connoissances Chimiques. 

 t Phil. Trans. 1808, p. 223. 



