Borax.
Qualities. Form, irregular hexahedral prisms, slightly efflorescent. Taste, alkaline and styptic; when heated it loses its water of crystallization, and becomes a porous friable mass (calcined borax). Chemical Composition. Boracic acid, 34—soda, 17—water, 49. Solubility. It is soluble in 20 parts of water at 60°, and in 6 parts at 212°. Incompatible Substances. It is decomposed by acids; potass; by the sulphates and muriates of the earths, and by those of ammonia. Medicinal Uses. It is only applied in the form of powder mixed with 8 or 10 parts of honey, as a detergent linctus in aphthæ, &c. The Chinese employ it in inflammatory sore throats; for which purpose they first reduce it to an extremely fine powder, and then blow it through a reed upon the inflamed surface. Officinal Preparations. Mel Boracis. L. Adulterations. Alum, and fused muriate of soda, are substances with which it is sometimes sophisticated; to discover which, dissolve it in distilled water, and after saturating the excess of the base with nitric acid, assay the solution with nitrate of barytes and nitrate of silver.
SODÆ SUB-CARBONAS. L.E.D.
Sub-carbonate of Soda.
Qualities. Form, octohedrons, truncated at the summits of the pyramids; it effloresces when exposed to the air, and at 150° Fah. undergoes watery fusion, its crystals containing as much as seven proportionals of water; Taste, mild, alkalescent. Chemical Composition. Soda 29·5—carbonic acid 20·7. Solubility. It is soluble in two parts of water at 60°, and in considerably less than its weight of boiling water; it is insoluble in alcohol. Incompatible Substances are enumerated under Potassæ Carbonas. Med. Uses, are similar to those of the sub-carbonate of potass, but it is preferable to it for internal use, as being more mild and less nauseous; and moreover Fourcroy states it as his opinion that soda is more eligible for medicinal purposes than potass, on account of its analogy with animal substances, which always contain it, while on the contrary, no portion of potass is found in them. Sir Gilbert Blane assumes an opposite opinion, and observes that, as far as he can judge of the comparative powers of the two fixed alkalies, he should greatly prefer Potass to Soda, as a remedy for gravel, one reason of which he thinks may be found in the fact that the Soda is an element of the animal fluids, since it enters largely into the composition of bile, so that it is more likely to be arrested in the course of the circulation and diverted from the urinary organs. A gentleman, says Sir Gilbert, who was subject to frequent fits of gravel, and in the habit of making experiments on the small concretions which he passed, found that Soda dissolved them, but that Potass did not; nevertheless he experienced sensible relief, and even temporary cure, from the internal use of the latter alkali, but no benefit from the former. Are then the absorbents more disposed to take up soda than potass? The results of experience do not appear to sanction such a conclusion. Forms of Exhibition. It may be administered in solution, in an electuary, or in pills; when exhibited in the latter form, it must be previously deprived of its water of crystallization, (Sodæ Sub-carbonas exsiccata. L.) or the pills will fall into powder as they dry; unless where the water of crystallization is essential to the formation of the pill, as to that of Pill: Ferri comp. Dose, gr. x to ʒj, twice or thrice a day. See Form. 28, 143, 144.
SODÆ SULPHAS. L.E.D.
Natron Vitriolatum, P.L. 1787. Sal Catharticus Glauberi. P.L. 1745.
Qualities. Form, transparent prismatic crystals, which effloresce; when exposed to heat, they undergo watery fusion, that is, they melt in their own water of crystallization. Taste, saline and bitter. Chemical Composition. Sulphuric acid 24·64,—soda 19·36—water 56. Solubility. f℥j of water at 60° dissolves ʒiiiss; in boiling water it is considerably more soluble; it is quite insoluble in alcohol. Incompatible Substances. The same as those which decompose sulphate of magnesia. Med. Uses. A common and useful purgative; its nauseous taste may be in a great degree disguised by the addition of a small quantity of lemon juice, or cream of tartar. Dose, ℥ss to ℥ij. In an effloresced state it is just equal in efficacy to double the weight of that which is in a crystalline form. It is rendered more active by being combined with other purgative salts, especially with sulphate of magnesia, and the compound is more soluble and less nauseous; (Form. 69, 72.) A portion of triple salt, a magnesio-sulphate of soda, probably results from the combination, a salt which may be frequently detected in parcels of sulphate of magnesia, and may be known by its crystals, which are regular rhomboids; it is also contained, according to Dr. Murray, in the brine or mother liquor of sea-water; and it constitutes the whole of that salt which was formerly sold under the name of “Lymington Glauber’s Salts”.[[645]]
SPARTIUM. L.E. Genista. D.
Spartii Cacumina. L. Summitates. E.