Gum

[A.S. goma, palate; Ger. gaumen.] (Anat.) The cellular and elastic fleshy substance which covers the alveolar portions of the upper and lower jaw, and envelops the neck of the teeth. -[A.S. goma; Fr.gomme; Lat. gummi.] ( Chem .) A vege table product, which forms a slimy solution with water, but is insoluble in alcohol, ether, and oils. There are six varieties of gum- gum - arabic, gum Senegal, gum of the cherry and other stone-fruit trees, gum tragacanth, gum of Ba ora , and the gum of seeds and roots. All these gums, except the last, flow spontaneously from the branches and trunks of their trees, and sometimes from the fruits in the form of a mucilage, which dries and hardens in the air; the gum of seeds and roots, however, requires to be extracted by boiling water. A number of very different substances are confounded in commerce under the name of gum. Thus, gum elemi , and gum copal, which are true resins; gum ammoniacum, which is a gum resin; and gum elastic (caoutchouc), which differs from both, are all called gums. Gum-arabic is obtained from the Acacia Arabica , or Acacia vera , which grow upon the banks of the Nile and in Arabia. The commercial gum of this kind consists of a number of small pieces rounded on one side and hollow on the other. It may be bleached by exposure to the atmosphere and sunlight at a temperature of 2120. Its specific gravity is 1.355. It is used in medicine, and also in order to give lustre to crapes and other silk fabrics. Gum Senegal is collected from the Acacia Senegal by the negroes during the month of November. Its specific gravity is 1-436, and its chemical properties and uses are similar to those of gum-arabic. It is largely used in calico-printing. Gum tragacanth, called also Cerasine, Cerasium, and Mucilage, is gathered in Crete and the neighboring islands, from the Astral a gus tragacan tha , about the end of June. It is white or reddish in color, almost opaque, and has the appearance of twisted ribands. It is difficult to pulverize it without heating the mortar. When plunged into water, it partially di olves, swells, and forms a very thick mucilage. Gum tragacanth has a specific gravity of 1-384, and is used in calico-printing and by shoemakers. Most of the substances called gums are resins or gum-resins. See RESIN. Gum, v. a. To unite by a viscous substance. -v. n. To exude or form gum. Gumbin'nen, a town of E. Pru ia, on the Pi a, 63 m. E. of Königsberg. Manuf . Cloths, hats, brandies, beer, and leather. Pop . 800. Gum'bo, ломво, п. A name applied in Louisiana to the plant Okro, of the genus HIBISCUS, q. v., and also to a soup of which the pod of that plant is the principal ingredient.