ON CANTHARIDES. 41 



chines a water-tight trap-door raay be made at F, for the puF- 

 pofe of removing the fand when it is overcharged with impu- 

 rities. The fmall diameter of the machine from which the 

 drawing was taken, was eight inches from B to E : the per- 

 pendicular height from C to A B was eight inches and three- 

 fourths, and from C to D four inches and one-twelfth. 



IX 



Medico-Chemical Reftarches on the Virtues and Principles qf 

 Cantharides. % H. Beaupoil. 



(Concluded from Page 71 of Vol. VUI.) 



IaE alfo proved that the black precipitate eaiily became dry. Experiments and 



obfervations 

 cantharides* 



brittle, and friable in the air; that it reddened the tinfture of ^'^^^f ^^51°"^ o"* 



turnfole; that it combined very readily with potafli, difen 



gaging ammonia; that, when diftilled by an open fire, it 



fwelled and yielded an acid liquor, a thick oil, and carbonate 



of ammonia; and that it left a dry, fhining, friable coal in the 



iretort. 



Proceeding afterwards to the examination of the yellow mat- 

 ter remaining in folution in the alcohol, Cit. feeaupoil informs 

 lis, that, when it is concentrated by the evaporation of its 

 folvent, it retains the fame odour and the fame tafte as the 

 fextrafl ; that it is completely ditToIved in water, and reddens 

 the tin6lure of turnfole ; that it combines entirely with potafh, 

 without any difengagement of ammonia ; and that the refultof 

 Ihis combination is an homogeneous and glutinous body, foluble 

 in water and precipitable by a weak acid ; finally, that, dif- 

 tilled by an open fire, it fwells very little, yields an acid liquor, 

 a black and fetid oil, and carbonate of ammonia ; but that, in 

 general, all thefe products are in fmaller quantity than in thofe 

 obtained from the black precipitate. 



Among thefe different refults the author thought it necefTary 

 to diredl his attention more particularly to the acid, which, as 

 has been feen, manifefls itfelf To readily in the infufion of can- 

 tharides, or ill the extract which they afford. 



At fir ft he was of opinion that this acid was analogous to that 

 pf vinegar ; he alfo thought that its exiflence might be attri- 

 ■'■ ^- , buted 



