Analysis of Aloes. 229 



its combustion a slight charry trace, and a remarkable smell 

 of prussic acid, which might lead us to suspect the presence 

 of azote. 



, We may easily produce this red detonating substance, by 

 pouring on the yellow acid of aloes a slight warm solution 

 of caustic potash, which has but a weak dissolving action 

 upon it. 



The nitric liquor, from which the yellow aloelic acid has 

 been separated, was saturated by potash. A very small 

 quantity oF red detonating matter was deposited at the end 

 of four-and-twenty hours. Nitrate of lime, which was 

 poured upon it, produced an abundant precipitate of oxalate 

 of lime: when well washed and dried it weighed 3-*- grammes. 

 The liquor separated from the oxalate of lime was precipi- 

 tated by the nitrate of lead. The sediment, when treated 

 with one third of its weight of weak sulphuric acid, fur* 

 nished about one gramme of malic acid, partly dried. 



§ VII. It results from the above facts, that aloes is not 

 a gum resin as has been thought, since we do not find in it 

 either the one or the other of these associated principles : 

 nor can we class aloes among the resins, although it resem- 

 bles them much more than the gums. It is therefore a 

 principle std 'generis, which I propose, from its properties, 

 to call resino amer. This principle is probably widely diffused, 

 and has its species like other vegetable substances. It is this 

 which had been at first confounded with the resins, which 

 have been sometimes taken for oxygenated extractive matter, 

 and which M. Vauquelin has amply described in his interest- 

 ing memoir upon different species of quinquina. It is also 

 the same substance which is deposited more or less abun- 

 dantly from the decoctions of many of the bitter plants, in 

 which febrifuge virtues have been for a long time recog- 

 nised ; such as the artemisia alsyvt hium , the centauria cal- 

 citrapa and benedtcta^ chicory and fumitory *. 



It is true that the virtues of these plants have been 

 reckoned less efficacious than the astringent febrifuges : and 

 I am persuaded that in kina, the principle which acts spe- 

 cifically against the fever, and the periodical return of dis- 

 eases, is owing to the combination oi the resino amer with 

 tannin, or some similar substance. My colleague, Dr. Hal- 

 dats, directed by these views, is about to enter upon some 

 important experiments, of which he will give an account, 



* It appears to me that the resiniform matter found in the bile by M. The- 

 jurd greatly resembles the rcsinu-amer of aloes. 



P 3 and 



