CATECHU, Terra japonica, catch.
Shia-dza, . . BoRM. Katchu, . . . GER.
Sha-si Kuth ; Catch, . .
Cutt, CAN. Katha ; Khair, . HIND.
Wu-tie-ni, . . CHIN. . . . . IT.
Wu-tieh -ni, . „ Kachu (of Acacia), MALAY.
Hai-rh-cha, . . „ Gambia (of Uncaria), „ Rh-ch'a, Yang-cha„Catch, . . . . PORT.
Cachou, . . . . 'Fn. Kash katti, . . . TAM.
Several astringent extracts prepared from the baiks, and fruits of various plants are known as catechu, cutch, terra, terra japonica, and gambier. They form articles of commerce, and are employed in tanning and dyeing. That called kut or kutch by the natives of the East, and cutch and terra japonica in commerce, is an extract prepared by cutting into chips the inner brown coloured wood of the Acacia catechu, and making a decoction, which is afterwards evaporated to a proper consistence. The extract from the Uncaria gambier is also known in the market as cutch, as also is the extract from the nuts of the Areca catechu. At the Madras Exhibition of 1855, catechu was seen in the form of-1. Circular flat cakes from Travancore, covered on both sides with paddy husks. 2. Large flat cakes from the Northern Division, varying in colour from brick dust to dull yellow. 3. Round balls of a dark brown colour, the size of a small orange, from Mangalore, where a large manufacture takes place. These sorts appeared to vary only in shape. The manufacturers from the Acacia catechu work in Burma, Canara, the western Dekhan, Behar, and Northern India. They move to different parts of the country in different seasons, erect temporary huts in the jungles, and, selecting trees fit for their purpose, cut the inner wood into small chips. These they put into small earthen pots, which are arrayed in a double row along a fireplace built of mud; water is then poured in until the whole are covered. After a considerable portion has boiled away, the clear liquor is strained into one of the neighbouring pots, and a fresh supply of material is put into the first, and the operation repeated until the extract in the general receiver is of suffi cient consistence to be poured into clay moulds, which are generally of a quadrangular form. Before the extract is quite dry, it is placed in cloths, strewed over with the ashes of cow-dung, cut into small lumps, and again exposed to the sun. This catechu is usually of a blood-red colour, and is considered there to be of the best quality.
Catechu has long been employed in India for tanning skins. Its tanning properties are stated to be so great that skins are tanned by it in five days ; but the leather is light, spongy, _permeable to water, and of a dark reddish-fawn colour. The light-coloured variety of catechu produces a softer leather than that tanned with cutch. Catechu
produces but little of the deposit of bloom which is yielded by oak-bark, valonia, and divi. A pound of catechu is said to be sufficient for the production of about a pound of leather. Bombay catechu or cutch is the richer in tannin ; it is of a dark brownish-red colour, internally as well as externally, and of sp. gr. 1'38. Bengal catechu or terra is of a light-brown colour internally; its sp. gr. is 1-28. It has also been used in India to give a brown dye to cotton, and has been very extensively employed in the calico-printing works of Britain. The salth of copper, with sal ammoniac, cause catechu to yield a bronze colour, which is very permanent. The proto-muriate of tin produces with it a yellowish-brown. A fine deep bronze hue is also produced from catechu by the perchloride of tin, with an addition of nitrate of copper. Acetate of alumina gives a brown, and nitrate of iron a dark-brown. For dyeing a golden coffee-brown, catechu has entirely super seded madder, one pound of it being equivalent to six pounds of that root.
A catechu prepared from the nuts of the Areca catechu. is used solely as a masticatory. The nuts, however, yield two astringent prepara tions, both of which are known as• catechu, and both of a very inferior quality. The preparations are respectively called, in Tamil, Katha kambu and Kash katti ; in Telugu, Kansi ; and in the Dekhan, Khrab katha and Acha katha. Katha kambu is chewed with the betel leaf ; the latter, Kash katti, is used medicinally. For preparing this substance, the nuts are taken as they come from the tree, and boiled for some hours in an iron vessel. They are then taken out, and the re maining water is inspissated by continual boiling. This process furnishes kassu, or the most gent terra japonica. After the nuts are dried, they are put into a fresh quantity of water and boiled again ; and this water being inspissated, like the former, yields the best or dearest kind of catechu. Sir H. Davy, in analyzing the dark and pale catechu, or the Bombay and Bengal, as they were called, obtained in 200 parts from Insol.
Tannin. Extract. Mucilage. residuum. Dark catechu, 109 68 13 10 Pale do. 97 73 16 14 When of good quality, catechu is a more powerful astringent than kino. Catechu is much used in medicine as an astringent and tonic, being usually given in combination with aromatic and earthy substances.—Simmonds ; Malcorn's Tr. i. 187 ; M'Clell. Repts.; Mad. Exh. Jur. Rep. ' • O'Sh. Disp. p. 302 ; Boyle'. Mat. Med. p. 351 • Faulk. ; Kerr, Med. Obs.andInquiries,v.; Hamil. Mysore, iii. See Acacia catechu ; Areca catechn ; Uncaria gambier.