N EW flPEClBS or URINARY CALCULX^*. gj 



only one otlier specimen of the same substance. This last ^ 



U in a collection of calculi belonging* to Guy's. Hospital, 

 j^iven by Mr. Lucas, sur^^eon to that institution, having 

 been formed partly by his father, and partly by himself^ . 

 in the course of their practice; and accordinj^ to the pre- i. 



sent arrangement, (which, it is to be hopod, will not be 

 altered) the calculus to which lallude may be found by refe- 

 rence to No. 46 of that coilecbon. It was extracted by the- 

 usual operation from a man of 36 years of age, of whom*; ! 



no record is preserved, except that, his name was Williaia- 

 Small. It weighed, when entire, 270 'grains. 



In appearance, these calculi resemble more nearly the Descri^tioa •l^ 

 triple phosphate of magnesia than any other calculus ; but ^** 

 they are more compact than thatjpompound is usually^ found 

 to be: not consisting of distinct laminae, but appearing as; 

 one mass confusedly crystallized throughout its substance. 

 Hence, instead of having the opacity and whiteness obaerr- ; i 



able in fusible calculi, which consist of -a number of stnall 

 crystals cemented together, these calculi have a yellowish 

 semitransparency ; and they have also a peculiar glistening 

 lustre, likethat of a body having a high refractive density. 



When this substance is submitted to destructive distilla- Results of iU 

 tion, it yields foetid carbonate of ammonia,,, partly fluid, <^8t^i«t«on* 

 and partly in a solid state, and a heavy foetid oil, such as . 

 uswally proceeds from animal substances; and there re- 

 mains a black spongy coal, much smaller in proportion 

 than is found after the distillation of uric calculi, , 



Under the blow-pipe it may be distinguished from uric^'^^'^7 <*f '^»« 

 acid by the smell, which at no period resembles that of s^jjfr iim 



prussicacid; but in addition to the usual smell of bur-ned -'-1 



animal substances, there is a peculiar foetor, of whicJ%«l^ 

 cannot give a correct idea, as I know no «mell wl»*rch it ca». Peculiar smell, 

 be said to resemble. 



This species of calculus is so readily acted upon by the Acted on bv 

 g-enerality of common chemical ayents, that its character "*°^' cheniicai. ^ 

 may perhaps be most distinctly marked by an enuuieration * ; 



of those feeble powers, that it can resist. ' > - 



It is not dissolved (excepting in very small proporllon) by ^ceptions. 

 water, by alcohol, by acetic acid, by tartaric^ acid^,1by.:<5i-tfs^ , ^•,» 

 trie acid, or by Kuturaled carb^nate.of ammonia. ^ *** iil 



The 



