This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Senna Pharm. Lond, & Edinb. Folium orientale. Senna: the leaf of an annual, woody, pod-bearing plant (senna alexandrina five foliis acutis C. B. Caffia (senna) foliolis trijugatis qua-drijugatisque Linn.) brought dry from Alexandria in Egypt. It is of a lively yellowish green colour, an oblong somewhat oval figure, (harp-pointed at the ends, about a quarter of an inch broad, and not a full inch in length. Some in-feriour sorts are brought from Tripoli and other places: these may be distinguished by their being either narrower, longer, and sharper pointed; or larger, broader, and round pointed, with small prominent veins; or large, obtuse, and of a fresh green colour without any yellow caft.
Senna is a moderately strong, and in general a safe cathartic: Geoffroy specifies hemorrhagies, inflammations of all kinds, and disorders of the breast, as being almost the only exceptions to its use. The dose in substance is from a scruple to a dram; in inflation, from one dram to three or four. It gives out its virtue both to watery and spirituous menstrua: to water and proof spirit it communicates a brownish colour, more or less deep according to the proportions; to rectified spirit, a fine green. There are two inconveniences often complained of in this medicine, its being liable in moil constitu-tions, to occasion gripes; and its being accom panied with an ill flavour, which is apt to nause-ate both the stomach and the palate. The first may be greatly obviated by dilution, the latter by aromatic and other additions; several com-positions of this kind are prepared in the shops, both sufficiently palatable, and which operate for the most part with ease and mildness.
The most-simple infusion is that ordered by the London college, in which six drams of senna with half a dram of powdered ginger are directed to be macerated during an hour in half a pint of boiling water. For the acidulated infu-sions, six drams of tamarinds, one of crystals of tartar, half a dram of coriander seeds, half an ounce of brown sugar, and one, two or three drams of fenna are infused in eight ounces of boiling water, in an unglazed earthen vessel, for four hours, and then (trained. Or three drams of fenna are infused in a quarter of a pint of boiling water, till the liquor has grown cold, with a dram of coriander seeds bruised, and half a dram of crystals of tartar, which last are previously boiled in the water till dissolved; or with two drams of fresh lemon peel, and two drams by measure of lemon juice. The former committee of the London college observed, that this last: was the most agreeable form, they had been able to contrive, for the exhibition of fenna to those who are more than ordinarily offended with its flavour; and that though acids are generally supposed to impede the action of water on vegetables, yet the infusions of fenna made with acids were found, from experience, not to fail in their intention. Indeed if the acids really weaken the dissolving power of the water, which it is probable they do in some degree, it should seem to be, on this account, rather of advantage than otherwise; for, as the committee further observed, in a medicine very nauseous to many, it is of primary consequence that only the lighter and least disgustful parts be extracted. On this principle, some macerate the fenna for a night in cold water, which becomes sufficiently impregnated with its purgative virtue, without extracting so much, as boiling water does, of the nauseous matter; if the liquor, poured off from the senna, be boiled a little by itself, great part of its ill flavour will be dissi-pated; and the remains of its offenfivenefs may be covered by infusing in it some bohea tea. If the coction is continued for any considerable time, the purgative virtue of the fenna will be diminished; for the infpiffated watery extracts are scarcely found to purge so much, as one fourth of the infusion or decoction they were made from, or so much as an equal weight of the leaves in substance. The London college have now admitted an extract of this kind.
Inf. fennae smpl. Ph. Lond.
Infusum ta-marindorum cum fenna Pl Ed.
Infuf. fennae tartarifat. Ph. Lond.
Infuf. fennae limoniatum.
The officinal spirituous tinctures of fenna are prepared by digestion for some days, in proof spirit. The proportions, in the London pharmacopoeia, are three ounces of fenna to a quart of the spirit, to which are added four ounces of stoned raifins, three drams of caraway seeds, and one dram of lessler cardamom seeds husked: in the Edinburgh, two ounces of fenna to three pounds and an half of the spirit, with the addition of one ounce of jalap, half an ounce of coriander seeds, and four ounces of white fugar, candy in powder, which last is directed to be dissolved in the tincture after draining, it from the other ingredients. Both these tinctures are agreeable and useful carminative purgatives, especially to those who have accuslomed them-selves to spirituous liquors; the ill flavour of the fenna is in great measure covered, and its offending the stomach or producing gripes prevented, by the warm seeds and the sweets. Several compositions of this kind have been offered to the public, under different names: the two above are inferiour to none; and supe-riour to moil of them.
Extr. fennae Ph. Loud.
Tinctura fen-nae Ph. Lond.
Tinct, fennae comp. vulgo elixir falutis Ph. Ed.