ing to Hennig, kino consists of tannic acid about 40 per cent, with a trace of gallic acid, kinoic acid, pectin, ulmic acid, and inorganic salts, with excess of earthy bases. (See A. J. P., xv, 544.) C. Etti obtained a new constituent, kinoin, by extracting kino with ether. He finally adopted the following method as more practicable. One part of gum kino is added to 2 parts of boiling diluted (1 to 5) hydrochloric acid. Kino-red immediately separates as a soft mass, becoming gradually solid on cooling, while the kinoin, mixed with a small quantity of kino-red, remains in solution. The solid residue is once more boiled with water, the liquids are united and shaken with ether. The ethereal solution, on evaporation, leaves a crystalline reddish residue, which is dissolved in hot water, on tile cooling of which tolerably pure crystals of kinoin are obtained. By continued recrystallization they are obtained colorless. Their formula is C14H12O6, and kino-red is the anhydride of this:
2C14H12O6—H2O = C28H22O11
This kino-red heated to 160° to 170° C. (320°-338° F.), parts with a molecule of water and yields a lower anhydride, C28H20O10. Both anhydrides are precipitated by gelatin, but kinoin itself is not. When heated with hydrochloric acid to 120° to 130° C. (248°-266° F.), kinoin yields methyl chloride, gallic acid, and catechol, and hence probably has the constitution of a guaiacol or methyl-catechol gallate. Kino contains about 1.5 per cent. of kinoin. (Ber. d. Chem. Ges.; N. R., Feb., 1897.) Kremel found Malabar kino, Butea gum, eucalyptus kino, and the kino from Coccoloba uvifera to be free from Etti's kinoin, but to contain a body acquiring, like kinoin, a red color with ferric chloride, which proved to be pyrocatechuic acid; this was present either alone or mixed with gallic acid. (A. J. P., 1883, 267.) Some doubt was also thrown upon the value of Etti's conclusions by White (P. J., 1903, p. 676), who failed to find several of the constituents reported by Etti. The true chemistry of kino may therefore be considered to be in a somewhat doubtful state. This is probably due to the fact that many different drugs have appeared in commerce under that name. Kino contains in its natural condition an oxidizing enzyme or oxidase which is the cause of the gelatinization which takes place in preparations of this drug. This enzyme can be destroyed by heat and advantage is taken of this fact in making Tinctura Kino (which see). In an examination made by David Hooper of ten varieties of East Indian kino, the proportion of tannic acid was found, after thoroughly drying the kino, to vary from 80 to 97 per cent. of the whole mass. (Agricultural Ledger of India, No. 11, 1901.)
It is said that catechu, broken into small fragments, has sometimes been sold as kino. Genuine kino is sometimes substituted by the extract of krameria. The latter is more brittle and dissolves, more quickly in water.
2. WEST INDIA OR JAMAICA KINO.—This is believed to be the product of the Coccoloba uvifera L., or sea-side grape. It grows in the West Indies and neighboring parts of the continent. The kino is said to be obtained by evaporating a decoction of the wood and bark, which are very astringent.
Although it has been many years since any large quantity appeared in our markets, it may occasionally be met. It is contained in large gourds, into which it was evidently poured while in a liquid or semi-liquid state, and then allowed to harden. When taken from the gourd it breaks into fragments of various sizes, upon an average about as large as a hazelnut, and having some tendency to the rectangular form. The consistence of these fragments is uniform, their surface smooth and shining, and their color a dark reddish-brown approaching to black. They are, however, neither so glistening nor so black as the East India kino. In mass they are quite opaque, but in thin splinters are translucent and of a ruby redness. They are readily broken by the fingers into smaller fragments, are easily pulverized, and yield a dull-reddish powder, considerably lighter colored than that of