Catechu vulgo Terra Japonica Pharm. Lond. Terra japonica dicta Pharm. Edinb. Japan earth, improperly so called. *The plant which yields the terra japonica, grows in the East Indies, and is called coira, or caira, by the natives of Bahar province. It appears to be the same with that mentioned by Cleyerus and Herbert de Jagur, from which the natives of Pegu prepare this extract: they name the tree Kheir or Khadira.

It is a species of the genus mimosa of Linnaeus, and called by him mimosa catechu. Its stem grows to about a foot in thickness, and from three to five feet high. It branches out into a thick spreading top, seldom above twelve feet high. The bark is thick and rough. The wood is extremely hard and heavy; its exteri-our part varies from a pale brown to a dark red, sometimes approaching to black, but always covered with one or two inches thick of white wood. The leaves are doubly pinnated, and have two prickles at the base. From the axillas of the leaves, arise dense spikes of small flowers, succeeded by pods.

The terra japonica is an extract of the wood of this plant, prepared in the following manner. After the trees are felled, the exteriour white wood is carefully cut off, and the interiour coloured part is cut into chips, with which narrow-mouthed unglazed earthen pots are filled, and water poured upon them till it appears among the upper chips. When this is half evaporated by boiling, the decoction, without draining, is poured into a flat earthen pot, and boiled to one third part; this is set in a cool place for one day, and afterwards evaporated by the heat of the fun, sturing it several times in the day; when it is reduced to a considerable thickness, it is spread upon a mat or cloth which has pre-viously been covered with the ashes of cow-dung; this mass is divided into square or quadrangular pieces by a string, and completely dried by turning them frequently in the fun.

This extract is called by the natives cutt; by the English cutch. In making it, the pale brown wood is preferred, as it produces the fine whitish extract. The darker the wood is, the blacker the extract, and of less value. Front the slovenly manner in which the preparation is made, it generally contains a considerable quantity of earth, besides what may be designedly put in it for the purpose of adulteration (a).

This concrete is a mild astringent, more agreeable in taste than most of the other sub-stances of that class, being accompanied with a considerable degree of sweetness. It is often suffered to dissolve leisurely in the mouth; both as a topical restringent for laxities and exulcerations of the gums; and in alvine and uterine fluxes, and catarrhal coughs and hoarseness; medicines of this kind acting in general to much better advantage when thus gradually swallowed, than when taken in full doses at once. With this view the terra japonica is made in the shops into troches; beaten with equal its weight of gum-arabic, and four times the weight of both of sugar of roles, and so much water to be dropt in as will reduce them into a mass of a due consistence for being formed. The Edinburgh college directs a compound electuary, of which terra japonica is the basis, joined with other astringents and aromatics, and a small proportion of opium, which is a very elegant and efficacious medicine of the kind.

(a) From Mr. Kerr's account, in vol. v. of the London Medical Observatios.

Japan-earth dissolves almost totally in water, excepting the impurities; which are usually of the sandy kind, and in considerable quantity, amounting, in the specimens I examined, to about one eighth of the mass. Of the pure matter, rectified spirit dissolves about seven eighths, into a deep red liquor: the part, which it leaves undissolved, is an almost insipid mucilaginous substance. In the shops a solution of it is made in proof spirit, with the addition of cinnamon, a spice the best adapted of any to the intention of this medicine; three ounces of the japan earth and two of cinnamon are digest-ed in a quart † or two pounds and a half ‡ of the spirit, and the strained tincture given commonly in doses of two or three tea-spoonfuls. It dis-solves also in volatile alkaline spirits, in alkaline lye, in the mineral acids, partially and more difficultly in the vegetable acids, and not at all in oils; all the solutions are of a red or purplish colour.

Trochifci e terra japon.

Electuar. japonic. vulgo content, ja-pon. Ph. Ed.

Tinctura catechu † Ph. Lond.

- japonic. ‡Ph. Ed.

*By the natives where this extract is made, it is employed medicinally as a cooler in the diseases considered by them as of a hot nature. It is said, when profusely used, to destroy the venereal appetite. It is given at the rate of two ounces a day to tame vicious horses. It is a principal ingredient in one of their ointments of great repute, composed of blue vitriol four drams, Japan-earth four ounces, alum nine drams, white resin four ounces; these are reduced to a fine powder, and mixed by the hand with ten ouncs of oil-olive, and water enough to give the mass a proper consistence. This ointment is used in every fore, from a fresh wound to a venereal ulcer; and has been found remarkably serviceable by European practitioners (a).