136 



and in ether. 



Alkalis as be- 

 fore. 



Ammonia dif- 

 folves it cold. 



Cryftalsof bili- 

 ary calculi. 



Description. 



EXfERIMlNTS AND OBSERVATIONS 



to the procefs by which it is obtained, or the rapidity of its 

 production ; in. my experiments the quantity which the alcohol 

 was capable of diflblving, though very considerable, was cer- 

 tainly lefs than that dated by Fourcroy. The greater part is 

 depofited as the fluid cools, and the remainder may be preci- 

 pitated by water. The adipocire, after this operation, is ren- 

 dered nearly white, while the alcohol aflumes a deep yellow 

 tinge. Ether diffolves it fparingly, when unaflifted by heat ; 

 when boiling it takes up about | of its own weight ; this is for 

 the moft part feparated by the cooling of the fluid; the adipocire 

 is depofited nearly white, while the ether acquires ayellowifh 

 green colour. The cauftic alcalis, both fixed and volatile, 

 exert upon this fubftanee the fame kind of action which we 

 have defcribed in the former inftances ; when heated in con* 

 tact with it, they form a faponaceous emulfion of a reddifh 

 brown colour, which is mifcible with water without decom- 

 polition. The volatile alcali diflblves it fparingly, without the 

 affiftance of heat ; a circumftance in which the adipocire dif- 

 fers both from any of the fubftances which we have hitherto 

 examined, and alfo from the cryftalline matter of biliary cal- 

 culi. Upon the whole the adipocire is more fufible, more 

 inflammable, and more eafily acted upon by the different re- 

 agents than any fubftanee which has paffed under our review. 



Cryftalline Matter of Biliary Calculi. 



It now only remained to perform fome comparative experi- 

 ments with the cryftalline matter of biliary calculi, and I was 

 fortunately in poffeffion of two of thefe bodies, which were 

 prefented to me by Dr. Gerard of this place. The calculi 

 were fimilar in their texture and appearance, and of nearly 

 the fame fize; the one which I examined was of an irregular, 

 polyhedral figure, with its edges and angles blunted ; it was 

 fomewhat brittle, and of an ochry brown colour. Its fpecific 

 gravity was about ,9000; it weighed 16 grains. When 

 broken, and viewed through a microfcope, it was found to 

 confift of an internal nucleus, formed of radii converging to a 

 centre, and of an external cruft compofed of four or five thin 

 ftrata. It evidently confifted of two diftinft fubftances ; one 

 white, fparkling, and of a cryftalline texture, by which its 

 general ftruclure was determined ; the other a number of dark 

 coloured particles, irregularly difperfed through the interfaces 



of 



