The clear supernatant portion of aloe juice, from which the above crystals have subsided, would probably also yield, by spontaneous evaporation, an extract resembling, or identical with, Socotrine aloes.
That Socotrine and hepatic aloes were obtained from the same plant, and were not different species of aloes, I have long suspected; and in the first edition of my work on Materia Medica, published in 1840, I have observed that “the similarity of the odor of Socotrine and hepatic aloes leads to the suspicion that they are obtained from the same plant; and which is further confirmed by the two being sometimes brought over intermixed, the Socotrine occasionally forming a vein in a cask of the hepatic aloes.”
The intermixture of the two sorts of aloes in the same cask might be explained by supposing that the consolidation of the clear portion of the juice has produced the so-called Socotrine aloes; while the opaque aloin containing portion of juice has yielded what is termed hepatic aloes. {240}
In the third edition of my work above alluded to, I have stated that the name of opaque liver-colored Socotrine aloes might with propriety be applied to hepatic aloes. But until the present time I have been unable to offer a plausible explanation of the cause of the difference in these two commercial kinds of aloes.
From the preceding remarks I think we may infer:
1. That aloin pre-exists in a crystalline form in the juice of Socotrine aloes.
2. That the substance which deposits as a decoction of Socotrine aloes cools, and which is usually termed the resin or the resinoid of Socotrine aloes, is the aloin in a modified state.
3. That hepatic aloes[22] is the juice of the Socotrine aloes plant which has been solified without the aid of artificial heat.
4. That hepatic aloes owes its opacity to the presence of minute crystals of aloin.
5. That the juice of Socotrine aloes yields, when evaporated by artificial heat, an extract possessing all the properties of commercial Socotrine aloes.—Pharm. Journ. April, 1852.