Natural History , S^c. 1 89 



9. Analysis of a Calculus. By M. Laugier. — ^This calculus was 

 removed after death from the bladder by a spoon, being too friable 

 to be otherwise handled. When dry it was of a deeper brown 

 colour than when moist. The calculus was analyzed by being 

 pulverized and boiled in successive portions of water which 

 removed uric acid, urate of ammonia and phosphate of ammonia. 

 Muriatic acid was then applied, which took up nothing but oxalate 

 of lime, and left merely animal matter. The results were 



o 1 1 1 • r Uric acid 1.0 



soluble m 1 tt * *• • ^ n 



' Urate 01 ammonia . . 4.0 



' [ Phosphate of ammonia 0.5 



Insoluble in f Oxalate of lime . . . 1.5 



water, '( Animal matter . . . 2.0 



Loss and water . . . 1.0 



10. 



Hence it may be remarked, 1st. That the animal matter was 

 present in much larger quantity than usual, 2. That urate of 

 ammonia is more soluble in hot water than is generally supposed. 

 3. That the phosphoric acid was combined with the ammonia and 

 not with the lime, as might have been supposed if the calculus 

 had been heated before the application of moist agents. 



M. Laugier then remarks, that having heated a portion of the 

 same calculus with a weak solution of caustic potash with the 

 intention of separating the uric acid from the oxalate of lime, he 

 found the latter to be entirely decomposed, and nothing but car- 

 bonate of lime left, the oxalic acid having entirely gone to the 

 alkali. Repeating the experiment with artificial oxalate of lime, it 

 was entirely decomposed by two portions of alkali ; and, again, 

 working on a very hard oxalate of lime calculus the same effect 

 took place. Hence it follows, that a solution of potash is not a 

 good means, especially when hot, of separating oxalate of lime 

 from substances soluble in that alkali, which contains almost 

 always carbonic acid, or can absorb it during the process. — 

 Jour, de Phar. x. 258. 



10. New Method of destroying Calculi. — The method proposed 

 by Dr. Civialo of destroying calculi in the bladder, has been re- 

 ported on to the Academy of Sciences by M. Percy. The following 

 is the account given of it in the AvMoles de Chimie : — A straight 

 silver sound is introduced through the urethra into the bladder ; 

 it contains a second also of silver and hollow, and terminated by 

 three spring branches which lie close together when confined by 

 the principal sound, but when pushed forward beyond it separate 

 and form a sort of cage into which, after a little while, the stone is 

 made to enter ; the operator then closes the cage ou it by drawing 



