vgg;^ ANALYSIS OF ALOES. 



cosity: in fact, a matter analagous to gelatine seemed to be 

 formedj for decoction of galls produced in them a preci- 

 pitate much more copious than in the recent solution. 

 These facts seem tome to prove, that aloes is not a resin. 



Solution of | IV. Spirit of wine, at 38"" [sp. grav. 0»827] dissolres 



aloes entirely with great readiness, particularly if hot, which 

 indicates the absence of gummy or extractive matter. The 

 solution, when filtered to free it from some particles of 

 foreign matter, is of so deep a red, that it is difficult to 

 perceive its transparency. Water produces in it a copious 

 sediment of a pale yellow colour. This colour is owing 

 to the water retained in it, for on drying, it assumes its 

 original brown. 



Crystallizable. If the alcoholic solution be evaporated, towards the end 

 we find, that the least motion, the slightest breath on it, 

 produces a sort of crystallization, which disappears again, 

 but is soon after reproduced. 



Aloes insoluble Though alcohol dissolves this substance very well, it is 



*"'^*^* not the same with oil, either fixed or volatile. I exposed 



to heat a mixture of olive oil and aloes: the latter remain- 

 ed fused at the bottom. Oil of turpentine boiled on aloes 

 Comported itself nearly in the same manner, but it acquired 

 a light amber tinge. 



Action of alka- § V. Alkaline solutions dissolve aloes very readily with- 



iis on aloes. ^^^ heat, and the results are combinations, in which the 

 bitterness appears partly concealed *. Acids throw down 

 from these solutions copious precipitates, which become co- 

 loured by desiccation. Volatile alkali diluted with water 

 likewise dissolves aloes completely. The filtered solution 



' was of a deep red, and' was evaporated slowly, lo expel 



the excess of ammonia. As the solution was concentrating, 

 a continual movement appeared on the surface, seemiug to 

 indicate a tendency to crystallization, for needles were ob- 

 served appearing and disappearing in succession. On con. 

 tinning the evaporation almost to dryness, needly crystals 

 ■were obtained, imbedded in a kind of resiniform mass. On 



* The mixture of seven drachms of tincture of aloes with one 

 drachm of the liquid subcarbonate of potash has the taste of asQ" 

 lutiou of extract of liquorice very nearly. C. 



heating 



