Tampico jalap yielded to one of us 10 per cent. of purified resin, entirely soluble in ether. Umney[1649] obtained 12 to 15 per cent. of resin almost wholly soluble in ether; Evans got 13 per cent., but found only about half of this to be soluble in ether.[1650] According to Andouard[1651] the resin of Tampico jalap is not deficient in purgative powers.
SEMEN KALADANÆ.
Semen Pharbitidis; Kaladana.
Botanical Origin—Ipomœa Nil[1652] Roth (Pharbitis Nil Choisy, Convolvulus Nil L.), a twining annual plant, with a large blue corolla, much resembling the Major Convolvulus (Pharbitis hispida Choisy) of English gardens, but having three-lobed leaves.[1653] It is found throughout the tropical regions of both hemispheres, and is common in India, ascending the mountains to a height of 5000 feet.
History—The seeds of this plant were employed in medicine by the Arabian physicians under the name Habbun-nil; and they have probably been long in use among the natives of Hindustan. In recent times they have been recommended by O’Shaughnessy, Kirkpatrick, Bidie, Waring[1654] and many other European practitioners in India as a safe and efficient cathartic.
Description—The shape of the seeds is that which would result if a nearly spherical body were divided perpendicularly around its axis into 6 or 8 almost equal segments, only that the back is less regularly vaulted. The seeds are ¼ of an inch high and nearly as much broad; 100 of them weigh on an average about 6 grammes. There is a smaller variety imported from Calcutta, of which 100 seeds weigh but little over 3 grammes; in every other respect the two sorts are identical. Both are of a dull black, excepting at the umbilicus, which is brown and somewhat hairy. The adjacent parts of the thin shell (testa) crack in various directions, if the seed is kept for a short time in cold water. If it is removed from the upper part of the vaulted back, the radicle becomes visible, surrounded by the undulated folds of the cotyledons, which join perpendicularly, but cannot be easily unfolded by reason of the thin seminal integument. Cut transversely, the cotyledons show the same curled structure. Throughout their tissue, small bright glands in considerable number are observable, even without a lens. The kernel, which is devoid of albumen, has at first a nutty taste, with subsequently a disagreeable persistent acridity. When bruised in a mortar, the seeds evolve a heavy earthy smell.
Microscopic Structure—The seed is covered with a dark blackish cuticle, formed of a densely packed tissue, the cells of which show zigzag outlines. The dark brown epidermis is composed of very close cylindrical cells, about 70 mkm. in length and 5 to 7 mkm. in diameter; they require to be treated with chromic acid in order that their structure may be distinctly seen.
The tissue of the kernels is made up of thick-walled cells. Between this tissue and the shell there is a colourless layer, about 70 mkm. thick, of thin-walled corky parenchyme. The cotyledons contain in their narrow tissue numerous granules of albuminous matter, mucilage, a little tannic acid, crystals of oxalate of calcium, and a few starch granules. The glands or hollows, before alluded to as occurring throughout the tissue of the cotyledons, are about 70 mkm. in diameter, and contain an oily liquid.
Chemical Composition—By exhausting the seeds dried at 100° C. with boiling ether, we obtained a thick light brownish oil having an acrid taste and concreting below 18° C. The powdered seeds yielded of this oil 14·4 per cent. Water removes from the seeds a considerable amount of mucilage, some albuminous matter and a little tannic acid. The first is soluble to some extent in dilute spirit of wine, and may be precipitated therefrom by an alcoholic solution of acetate of lead.
The active principle of kaladana is a resin, soluble in alcohol, but neither in benzol nor in ether. From the residue of the seeds after exhaustion by ether, treatment with absolute alcohol removed a pale yellowish resin in quantity equivalent to 8·2 per cent. of the seed.