This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Cassia pods are the ripe fruits of Cassia Fistula, Linne (N.O. Leguminosoe), a tree of moderate size, indigenous to India, and often cultivated as an ornamental plant (Indian laburnum). The tree bears a pendulous raceme of fragrant flowers, each with a one-celled many-seeded ovary, which develops into a long, leguminous fruit. As the latter ripens the seeds become separated from one another by the formation of numerous thin, transverse, spurious dissepiments, and the fruit, which was originally one-celled, becomes spuriously many-celled. It differs from a typical legume in being indehiscent as well as many-celled, and may be described therefore as a many-celled indehiscent legume.
The ripe pods, as met with in commerce, are long, nearly straight, cylindrical, dark chocolate-brown fruits attaining 45 to 60 cm. in length and 20 to 25 mm. in thickness. The surface, which appears smooth and shining to the naked eye, is seen under a lens to be marked with minute transverse striations; both the dorsal and ventral sutures are evident but not prominent. To one end of the fruit a short stalk is attached; the other terminates very abruptly in a short point.
The pericarp, although thin, is hard and woody. The interior of the fruit is divided into a number of compartments by transverse dissepiments placed about a quarter of an inch apart. Each compartment contains a single seed attached to the ventral suture by a long, dark, thread-like funiculus. A thin layer of nearly black firm pulp, which in the fresh fruit is soft and fills the compartment, adheres to each side of the membranous dissepiments. In very dry pods the pulp is often so much contracted that the seeds lie loose in the cavity and rattle when shaken; these are less esteemed.
The seeds are flattened-ovoid, reddish brown, smooth, and extremely hard. When cut transversely they exhibit a curved yellow embryo obliquely crossing a whitish horny endosperm. The pulp has a sweetish taste and a somewhat sickly odour.
The pods are exported from the West Indies (Dominica) and from Java. From the West Indies they arrive in cylindrical baskets made of plaited split canes.
The student should observe
(a) The smooth surface and long cylindrical shape,
(b) The spurious dissepiments with adhering pulp, '
(c) The odour and taste.
The pulp, which is the only official part of the fruit, is separated by crushing the fruits, macerating them with water, straining the liquid, and evaporating it to a soft extract. It contains about 50 per cent, of sugar and also oxymethylanthraquinones (not yet investigated); both of these probably contribute to its laxative action.
Pods of Cassia grandis, Linne (horse cassia). Longer, thicker and heavier than those of C. Fistula; laterally compressed; surface rough; one prominent ridge on the dorsal and two on the ventral suture; odour of pulp disagreeable, taste bitter and astringent.
Pods of C. moschata, Humboldt, Bonpland and Kunth. Smaller and narrower than those of C. Fistula; pulp paler, odour musk-like.
Cassia pulp is laxative, but is seldom used except as an ingredient in confection of senna.
Fig. 55. - Cassia Fistula. Lower portion of a pod partly opened to show the seeds. S, seed; w, transverse dissepiments; b, pericarp of fruit. (M o e 11 e r, after Wiesner).