SEN′EGIN. Syn. Polygalin, Polygalic acid. A white odourless powder, discovered by Gehlin in the bark of seneka root (Polygala Senega).
SEN′NA. Syn. Senna, Sennæ folia, L. There are three principal varieties:—
1. Alexandrian senna (senna Alexandrina—B. P., Ph. L., E., & D.), referred in the, Ph. L. to Cassia officinalis and Cassia obovata, in the Ph. D. to Cassia acutifolia (Delile), and in the Ph. E. to various species of cassia. The leaves are “unequal at the base, ovate acute, or obovate mucronate.” (Ph. L.) It is generally mixed with the leaves of Solenostemma Argel (argel leaves), the presence of which is often the occasion of much griping. The leaf of argel is fully an inch long, warty, regular in its formation, and the lateral nerves are imperfectly seen on the under side; whilst that of the true Alexandrian senna never exceeds 3⁄4 inch in length, is oblique, and the nerves on the under side are very conspicuous.
2. Indian senna (senna Indica—B. P.; Ph. L., & E.) is referred to Cassia officinalis in the Ph. L., and in the Ph. E. & D. to Cassia elongata (Lemaire, Lisancourt). The leaf is “unequal at the base,” and “Lanceolate.” (Ph. L.)
3. Tinnevelly senna, forming the finest Indian, now introduced into the Ph. D., is therein described as composed of the leaflets of Cassia oblongata. These are pale green, thin, flexible, and from 1 to 2 inches long, and nearly 1⁄2 inch broad. This variety is equal in medicinal virtue to the best Alexandrian, and is to be preferred, on account of its being imported perfectly free from adulteration.
Senna is purgative in doses of 10 to 30 gr., either in powder or made into an infusion of tea with Water, combined with ginger, caraways, or some other aromatic, to prevent griping. It acts chiefly on the small intestines, and generally effects its purpose within 4 hours after being taken.
SE′′PIA. A pigment prepared from the ‘ink’ or black fluid secreted by Sepia officinalis (Linn.), and several other varieties of cuttle-fish. The contents of the ‘ink bags’ are inspissated as soon as possible after collection, and then form the crude sepia of commerce. This is prepared for artists by boiling it for a short time in a weak lye of caustic alkali, precipitating the solution with an acid, and well washing and carefully drying the precipitate by a gentle heat. It possesses a fine brown colour, and is used like Indian ink.
SER′PENTARY. Syn. Virginian snake-root; Serpentaria radix (B. P.), Serpentariæ radix, Serpentaria (Ph. L. & E.), Aristolochia serpentaria (Ph. D.), L. An excellent stimulating diaphoretic and tonic; in typhoid and putrid fevers, dyspepsia, &c. It is admirably suited to check vomiting and to tranquilise the stomach, particularly in bilious cases. (Dr Chapman.)—Dose, 10 to 20 gr., every third or fourth hour, its use being preceded by an aperient.
SE′′RUM. Syn. Seralbumen. The clear pale fluid in which the blood-globules float, and which separates from blood during its coagulation. It is, essentially, a feebly alkaline solution of albumen. See Albumen.
SESQUI-. See Nomenclature.