Gum, Indian. Ghatti Gum.—Under the name of Gummi Indicum the Br. recognizes the gummy exudation from the wood of Anogeissus latifolia. The forests of India produce large quantities of other gums, a number of which have found their way into commerce and are used to a considerable extent as substitutes for gum arable and gum tragacanth. Indian gum occurs in yellowish-white tears having a vitreous fracture. It is entirely soluble in water, forming a thick mucilage.
Of the other "so-called" Indian gums, that yielded by Prosopis spicigera L. (Fam. Leguminosae) occurs in small, angular, yellowish fragments, or sometimes in large ovoid tears 5 cm. long, of an amber color, frosted externally with fissures. It forms with water a dark-colored tasteless mucilage and resembles in its behavior to reagents the Mezquite gum. The gum of Feronia elephantum Corr. (Fam. Rutaceae) is in small, irregular tears varying from reddish-brown to pale yellow and forms a thick, tasteless, colorless mucilage which resembles gum arable, but is precipitated by neutralized lead acetate and gelatinized by ferric chloride, although unaffected by borax. The most important of the Indian gums is that which is recognized in the Br. Pharmacopoeia, and which in its solubility and relation to reagents closely resembles gum arabic. This is the product of Anogeissus Latifolia above referred to. It has double the viscosity of gum arable and forms with water a colorless mucilage having a faint characteristic odor. It is well suited for pharmaceutical use, and is said to be specially valuable in the making of emulsions. It is insoluble in 90 per cent. alcohol. For further description of the properties of this gum see Gummi Indicum.
The Br. Pharmacopoeia allows of the substitution of Indian gum in official preparations in place of gum acacia, with the statement that one part of it should be substituted for two of the acacia. The mucilage of Indian gum (Mucilago Gummi Indici, Br., 1914) is made with two avoirdupois ounces of gum to six fluidounces of distilled water. See also Gum Sterculia.
The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.