Gummi Indicum. Br. Indian Gum.
"Indian Gum is a gummy exudation from the stem of Anogeissus latifolia, Wall." Br.
The genus Anogeissus (Fam. Combretaceae) includes four or five different species of tropical trees. Of these A. latifolia is widely distributed in Farther India. The tree is large and handsome, and one of the most useful of tropical India. The leaves are broadly elliptical, obtuse at the base and summit. They contain large amounts of tannin and are used in Bombay for tanning. The flowers are axillary and the fruit is 2-wmged, being arranged horizontally into dense heads. The gum from this tree is collected in April and is used extensively in calico printing, especially in Lucknow. It is less adhesive than Acacia and is usually used in connection with turmeric with which there is some specific combination.
"In vermiform or rounded tears of varying size, colorless or pale yellow; surface dull, fracture vitreous. Slight odor; taste insipid and mucilaginous. Entirely soluble in water, forming a viscous, adhesive mucilage. Insoluble in alcohol (90 per cent.). The aqueous solution is gelatinised by the addition of alcohol (90 per cent.), or solution of lead subacetate; but it is unaffected by the addition of T. Sol. of ferric chloride or of solution of lead acetate (distinction from Amrad and certain other gums). It is not colored blue or brown by a small quantity of N/10 solution of iodine (absence of starch or commercial dextrin). Ash not more than 4 per cent. In India and the Eastern Divisions of the Empire, Indian Gum may be employed in making the official preparations for which Gum Acacia is directed to be used, one part of the former being taken for every two parts ordered of the latter (see 'Mucilago Gummi Indici')." Br.
Uses.—Indian gum is used for the same purposes in pharmacy as acacia. It must not be confounded with the so-called India Gum which is only slightly soluble in water.
Off. Prep.—Mucilago Gummi Indici, Br.