OTf THE STRUCTURE OF CALCULI. 4j| 



The remaining portion of the calculus, weighing 54*8 Treated with 

 grains, was treated with small portions of acetic acid, by ace *° aci * 

 which 6 grains of the amraoniaco-magnesian phosphate were 

 obtained. 



- The part of the calculus remaining after this treatment, Residuum dis- 

 weighing 48*8 grains, was perfectly soluble in a solution f so jved in pot- 

 pure potash ; it emitted no ammoniacal odour when acted 

 upon by the alkali, and possessed the properties of pure uric 

 acid. 



The following therefore is the composition ofyhis calculus. Component 



part*. 



Grains. 

 Urea, and muriate of ammonia .... 5*2 

 Ammoniaco-magnesian phosphate • • 6* 

 Uric acid • • • • 48*8 



60- 



From these and many similar experiments upon other No urate of 

 calculi, hitherto generally supposed to consist of urate of ammoniaina ** 

 ammonia, I am induced to believe, that the evolution of 

 ammonia depends in all instances upon the decomposition 

 of the ammoniacal salts contained in the calculus, more es- 

 pecially of the ammoniaco-magnesian phosphate, and that 

 no substance, which can be called urate of ammonia, exists 

 in calculi. 



The mulberry calculus (oxalate of lime) I have but rarely Mulberry cat- 

 met with. In those preserved in the Hunterian Collection culi * 

 there is a large relative proportion of phosphate of lime, and. 

 of uric acid. The purest of them afforded 



Grs. 

 Oxalate of lime 65* 



Uric acid iQ» 



Phosphate of lime 15» 



Loss in animal matter • • • • 4 # 



100* 



When calculi of the urinary bladder increase to a very large very large cal- 

 size, they are generally composed of two or even three of culi seldom 

 the above mentioned varieties, the ammoniaco-magnesian omo S eneous « 



phosphate 



