Researches of Pitaya Bark. 
335 
A second experiment on a larger quantity of the bark, fully 
confirmed this fact. He boiled six ounces of Pitaya bark in 
distilled water, and obtained two ounces of extract which he 
treated by alcohol of 34°. Part of it was dissolved and put 
aside ; the undissolved part presented the characters of a 
gallate of lime. The alcoholic product was diluted with a 
little water, and submitted to distillation. The aqueous 
residuum left in the retort coloured litmus of a red colour ; 
precipitated a solution of gelatin, turned green the solution of 
sulphate of iron, and possessed an astringent and very bitter 
taste. These characters indicated already that this residuum 
contained tannin with an excess of gallic acid, a bitter sub- 
stance and colouring matter. The solution was, moreover, 
precipitated by ammonia, and a part of the yellowish white 
precipitate that was produced, was treated by ether, and af- 
forded by evaporation the tannate of the bitter substance or 
new vegetable alkali, leaving behind the colouring matter. 
The remaining part of the precipitate was treated with 
boiling water, which dissolved it partially ; the solution was 
slightly acidulated with sulphuric acid, then dissolved with 
animal black, and the excess of acid saturated by lime, and 
afterwards evaporated to dryness. The residue well dryed 
was dissolved in alcohol, in the state of sulphate, and per- 
mitted to crystallize. The crystals were acicular, and in the 
form of a fan. 
That of the residue that had not been dissolved by the 
boiling water, was treated by the hydrate of potassa, which 
produced a ruby red. The potassa having been saturated by 
an acid, the colouring matters were precipitated. 
From these experiments on related here, Mr. Peretti inferr- 
ed that the Pitaya bark contains — 
1st. A bitter principle, having the characters of an alcaloid. 
2d. Two different colouring matters united to gallic acid. 
3d. A gallate of lime. 
4th. Some gum. 
5th. Some resin. 
6th. A fibrous part. 
