Chemical Composition. Fecula, mucilage, an acrid volatile oil on which their virtues depend, and which on standing deposits a quantity of sulphur, a bland fixed oil, which considerably obtunds the acrimony of the former constituent;[[635]] and an ammoniacal salt. Solubility. Unbruised mustard seeds, when macerated in boiling water, yield only an insipid mucilage, which like that of linseed, resides in the skin; but when bruised, water takes up all the active matter, although it is scarcely imparted to alcohol. Medicinal Uses. It is a beneficial stimulant in dyspepsia; chlorosis, and paralysis; for which purpose, a tea spoonful of the bruised seeds may be administered; or a whey may be made, by boiling a table spoonful of the bruised seeds in oj of milk, and straining; of which a fourth part may be taken three times a day, (see Form. 46.) or it may be given in infusion. (Form. 45.) The farina made into a paste with crumbs of bread and vinegar, affords one of the most powerful external stimulants which we can apply, and is technically termed a Sinapism; it produces intense pain, and excites an inflammation entering much more into the true skin than that which is excited by the Lyttæ; it is therefore worthy attention in all internal inflammations where bleeding is limited: if necessary it may be quickened by the addition of oil of turpentine. If a table spoonful of powdered mustard be added to oj of tepid water, it operates briskly as an emetic. Officinal Preparations. Cataplasm: Sinap. L.D. Emplast: Meloes com: E.[[636]] (B) Infusum Armoraciæ comp: L. (B) Adulterations. Fine powder, or flower of mustard, as it occurs in commerce, contains only one-sixth part of genuine mustard, the remainder consists of flour, coloured by turmeric, and made pungent by the addition of powdered capsicum.
SODA TARTARIZATA. L. Tartras Sodæ et Potassæ. E. Tartarus Sodæ et Kali. D. olim. Sal de Seignette. Sal Rupellensis, or Rochelle Salt.
Qualities. Form, a right prism, with rhombic terminations, very slightly efflorescent. Taste, rather bitter and saline. Chemical Composition. It is a triple salt, formed by neutralizing the excess of acid in super-tartrate of potass, with soda, and consisting of 2 atoms of acid + 1 of soda + 1 of potass. By a strong heat it is resolved into a mixture of carbonate of potass and carbonate of soda. Solubility. It is soluble in five parts of water at 50°. Incompatible Substances. Most acids, and acidulous salts (except the Super-tartrate of potass) which convert the tartrate of potass into bi-tartrate, or super-tartrate. The acetate and sub-acetate of lead; barytic salts, and the salts of lime are decomposed by it. Med. Uses. Similar to those of Potassæ Tartras. See Form. 77, and 86, the latter of which presents a very grateful and efficacious purgative. Dose, ʒij to ℥j as a purgative.
SODÆ CARBONAS. L.E. Carbonate of Soda.
This salt, when properly prepared, is a bi-carbonate, but so delicately are the affinities of its constituent parts balanced, that the application of a very moderate temperature is sufficient to subvert them, and to occasion partial decomposition. Mr. Phillips states that although he has seen what he believes to be real bi-carbonate in the state of the moist crystals, yet he has never met with any that was dry which had not lost one-fourth of its carbonic acid by exposure to heat; it is then a white gritty powder, less soluble in water than the sub-carbonate, like which it possesses an alkaline taste, and turns vegetable yellows brown, but both in a less degree. This salt, which is generally sold, as the carbonate of the pharmacopœia, and the bi-carbonate of chemists, Mr. Phillips considers as a compound of an atom of carbonate, (sub-carbonate) and an atom of bi-carbonate, combined with four atoms of water. It is therefore, according to the phraseology of some chemists, a Sesqui-carbonate,[[637]] as being equal to an atom and a half of acid and one atom of base. The chemical habitudes of this salt, as connected with its medicinal applications, are similar to those of the carbonate of potass, which see. Med. Uses. As it is less nauseous, so is it more eligible than the sub-carbonate of the same alkali; in other respects its effects are the same; vide Sodæ Sub-carbonas. Dose, grs. x to ʒss.[[638]] Adulterations. If the salt, after super-saturation with dilute nitric acid, give a precipitate with nitrate of baryta, it contains some sulphuric salt; and if with nitrate of silver, we may infer the presence of a muriate.
SODÆ MURIAS. L.E.
Sal Commune, Murias Sodæ. D.
Muriate of Soda. Common Salt.
Qualities. Form, that of regular cubes, which do not deliquesce unless contaminated with muriate of magnesia.[[639]] Chemical Composition. It consists, according to Berzelius, of 46·55 of muriatic acid, and 53·45 of soda; according to the new theory, however, this salt must be considered as a true muriate of soda, only while it remains in aqueous solution; for when it is reduced to dryness, the muriatic acid and the soda become both decomposed, and the hydrogen of the former uniting with the oxygen of the latter, they pass off in the form of water, while the chlorine of the muriatic acid unites with the metallic base of the soda, to form chloride of sodium, which consists of an atom of each constituent. It is perhaps difficult to believe that the same salt should be chloride of sodium in the hand, and muriate of soda in the mouth! but it is not the less true, nor is it more incredible than the change which Sulphuret of potass undergoes by solution, the decomposition of which is rendered evident to the senses by the evolved sulphuretted hydrogen. Late researches have also detected both in rock and in other salt, the presence of muriate of potass, and muriate of magnesia.[[640]] Solubility. It is equally soluble in cold and in hot water, one part of the salt requiring rather more than 2½ parts. Med. Uses. The effects of salt upon the animal and vegetable kingdoms, are striking and important,[[641]] and have furnished objects of the most interesting enquiry to the physiologist, the chemist, the physician, and the agriculturist; it appears to be a natural stimulant to the digestive organs; and that animals are instinctively led to immense distances in pursuit of it; for proof of this fact the reader is referred to “Parkes on the repeal of the Salt Laws,” and to an interesting work by my late lamented friend, Sir Thomas Bernard, entitled, “Case of the Salt Duties, with Proofs and Illustrations.”[[642]] Salt, when taken in moderate quantities, promotes,[[643]] while in excessive ones, it prevents digestion; it is therefore tonic and anthelmintic, correcting that disordered state of the bowels which favours the propagation of worms. In Ireland, where, from the bad quality of the food, the lower classes are greatly infested with worms,[[644]] a draught of salt and water is a popular and efficacious anthelmintic. Form: 162, is a prescription by Rush, who says that in this manner he has administered many pounds of common salt with great success in worm cases. In the first volume of the Medical Transactions we shall find an interesting account of a cure of this disease by salt, after the failure of other remedies; I beg also to refer the practitioner to another case illustrative of its anthelmintic powers, published by Mr. Marshall, (London Medical and Physical Journal, vol. xxxix. No. 231,) which is that of a lady who had a natural antipathy to salt, and was in consequence most dreadfully infested with worms during the whole of her life. In very large doses Salt proves purgative; it is also absorbed, and carried to the kidneys, but it undergoes no decomposition in transitu, nor does it appear to possess any considerable powers as a diuretic; its solution in tepid water, in the proportion of ℥ss-℥j in oj of water, forms the common domestic enema. Dose, when intended to act as a cathartic, from℥ss to ℥j very largely diluted; when to answer the other intentions, from grs. x. to ʒj.
SODÆ SUB-BORAS. L.D. Boras Sodæ. E.