3rd, That the sesqui-chloride of iron, if in crystals, is easily and wholly soluble in ether, while the aqueous solution of it is but partially so, a portion being decomposed, as is evidenced by the solution becoming muddy. The ethereal solution, if prepared in the last mentioned manner, must be of uncertain strength, which is avoided by the first.
In Europe Bestucheff’s tincture is much used by physicians. It sometimes agrees better in the bleached state, sometimes when colored. When first prepared the tincture has a yellow hue, which it loses by exposure to the light of the sun. If, after it has thus been bleached, it is placed in a dark closet, it again becomes yellowish, though the color is not so deep as at first.
ON SOCOTRINE ALOE JUICE, OR LIQUID SOCOTRINE ALOES. BY JONATHAN PEREIRA, M. D., F. R. S., (Physician to the London Hospital.)
It has long been known that the Socotrine aloes imported into England varies considerably in its consistency, and is sometimes met with in a soft or semi-fluid state. Frequently, on opening a package of this sort of aloes, the interior is found to {236} be quite soft, while the exterior is firm and hard. In general this arises from insufficient evaporation of the aloe juice.
In the third edition of my Elements of Materia Medica, (vol. ii., part 1, p. 1077, published in 1850,) I have briefly referred to a soft or semi-liquid Socotrine aloes, which had a bright or palm-oil yellow color and odor. At that time I had but little opportunity of investigating this very interesting drug; but a large importation of it having recently taken place, I have more fully examined it, and, as it appears to me to be the raw or unboiled juice of the plant yielding what is known in commerce as Socotrine aloes, I propose to distinguish it from the ordinary soft Socotrine aloes by the name of “Socotrine Aloe Juice.”
Messrs. Horner, the holders of the whole of the present importation of this juice, inform me that it was purchased of the Arabs up the Red Sea, by a merchant, who was assured by the venders that it was very fine aloe juice, and had not been boiled or otherwise altered. It was imported into London by way of Madras, in casks each containing six cwt. I am informed that the contents of some of the packages have undergone decomposition during the voyage.
Its consistence is that of treacle or very thin honey; its color deep orange or palm oil yellow; its odor powerful, fragrant, and resembling that of fine Socotrine aloes. By standing it separates into two parts,—an inferior, paler colored, opaque, finely granular portion, and a superior, darker colored, transparent liquid. The latter forms, however, a very small portion of the whole mass.
When the granular portion is submitted to microscopic examination, it is found that the opacity and granular appearance arise from myriads of beautiful prismatic crystals. If a temperature of 132° Fah. be applied to the juice these crystals melt or dissolve, and the juice becomes deep red and transparent; and when the liquid becomes cold it retains its transparency, and does not deposit any crystals. By evaporation the juice yields a solid, transparent extract, having all the {237} characters of fine Socotrine aloes, in which no traces of crystalline texture can be discovered. Mr. Jacob Bell has ascertained that 14 lbs. of the juice yield 8lbs. 12ozs. of solid extract, or 621⁄2 per cent. when the juice is mixed with cold distilled water, it becomes opaque yellow, and renders the water turbid, but is not miscible with it. If, however, heat be applied, the juice dissolves in the water, forming an almost clear, rich red liquid. As the solution cools, it at first becomes turbid, owing to the separation of an opaque yellow precipitate, which, apparently, is the crystalline principle in an amorphous form. This gradually separates from the liquid and collects as a clear resiniform mass (commonly called the resin of aloes) at the bottom of the vessel, leaving the supernatant liquid tolerably clear. If the juice be shaken up with rectified spirit of wine, an uniform clear mixture is obtained, from which numerous yellow crystals rapidly fall to the bottom of the liquid. Similar results are obtained when we mix the juice with equal parts of rectified spirit of wine and water.
This crystalline constituent of Socotrine aloes is doubtless, either the aloin[21] described by Messrs. T. & H. Smith, of Edinburgh, and by Dr. Stenhouse, or a principle closely allied to it.