ELEMENTS OF MATERIA MEDICA.

646

Winkler (Schwartz, Pharm. Tabell . p. 294, 2 Ie Ausg-.) regards aloes as a neutralvegetable salt, composed of two peculiar basic substances (viz. a non-bitter resin, anda bitter substance,) and an acid, viz. a colouring, non-bitter matter.

Fabroni (Ann. de Chini. xxv. 301) obtained a fine viblet colour from the recent j uiceof the Aloe , which has been proposed as a dye for silk. JTt is formed by the action ot'the oxygen of the air on the^yutce.- > v "

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Chemical Characteristics. —Aloes is almbst completely solublein boiling water: as the decoction cools the substance v called resin(aloesin and puce-coloured principle, Braconnot) yibposits. The clearsolution reddens litmus, strikes a deep olive brown tint ( aloetate ofiron) with sesquichloride of iron, is deepened in colour by alkalies, butis unchanged by gelatin. Diacetate of lead forms a copious yello' v 'precipitate with it.

The cold decoction of Cape aloes is much paler coloured than that ofany other kind of aloes. Barbadoes aloes yields the deepest coloureddecoction.

Physiological Defects, (a.) On vegetables. —Not ascertained.

(b.) On animals. —Aloes is the ordinary purgative for solipedes (tb ehorse, the ass, the zebra, &c.) as it is both safe and sure. In horsedpreviously prepared by two or three hran-mashes to soften the dung, & 0dose is from five to seven drachms (Youatt, The Horse, p. 211). It actsslowly, requiring from eighteen to forty-eight hours for its operatic 11(Moiroud, Pharm Viter, p. 264). Mr. Youatt informs me that aloes is *valuable purgative for the dog, in doses of from one to three drachm 8 *and with the addition of from one to three grains of calomel. Barbados aloes is preferred by veterinarians, as being more effective than Cap 6aloes, in the ^jatio of about seven to five. Aloes proves purgative t°oxen, sheep, and pigs, but, as in the other cases, operates slowly (Viborg 111Wibmers Wirk. d. Arzneim). Moiroud (op. cit.) injected into the veins 0a horse four drachms of aloes dissolved in water with a little alcohol, ai’f,the next day an ounce, without any other effect than the evacuation 6a large quantity of urine. The dung, however, was enveloped by a thipellicle formed by altered intestinal mucus. This was collected aimanalyzed subsequent to the death of the animal (which followed thre edays after the injection): it offered scarcely any traces of the constituenof the bile. J

(c.) On man.— Taken internally in small doses, aloes acts as a tonicthe alimentary canal, assisting the digestive process, strengthening tjjmuscular fibres, and promoting the secretions, especially that of tnlivei, which organ it is thought specifically to influence. In largeit acts as a purgative. There are, however, some peculiarities attendingcathartic operation deserving of notice. In the first place, these effe 6are not so speedily produced as by some other purgatives; for eight, tweh ’and sometimes twenty-four hours elapse before they take place. .condly, aloes acts especially on the large intestines, and a full dose 1in some persons apt to produce heat and irritation about the rectumtenesmus, and, in those troubled with hemorrhoids, it is said not mmquently to increase, or even to bring on, the sanguineous discharg 'Jb allopius (Opera omnia, p. 109, Francof. 1600) tells us, that of one h«»red persons who used aloes as a purgative, ninety were affected with t ,hemorrhoidal flux, which ceased when the use of aloes was omi tie 'ut though this statement has been often referred to, it is of little 1

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