Page:The American Cyclopædia (1879) Volume VIII.djvu/335

 GUM GUM RESINS 321 ited with inferior gums, and also with starch id flour. Iodine readily detects the presence starch or of flour in solutions of gum con- lining them by the blue color produced. TRAGAOANTH, also called GUM DEAGON, is ie product of various species of astragalus, jecially the A. verus of the north of Persia, rmenia, and Asia Minor, and the A. gummi- fer of Arabia, Mt. Lebanon, &c. It is collect- in the months of July and August from the itural exudations of the shrubs, and from lose resulting from incisions made in the stem ir the root. It is a hard, tough substance, lore or less white according to its purity, in 3ry irregular flattened shapes, and in tortu- is vermicular filaments. It may be pulver- after drying at a temperature of 212. It no taste or smell. Its specific gravity is I '384. It swells slowly in water, partially dis- Iving, and forms a thick adhesive paste. By )iling with sufficient water, a solution is ained of similar appearance, and Brande inks of the composition, of that of gum ara- Different analyses are given of it, but that Guerin-Varry is generally adopted ; it is as Hows : arabine, 53*3 per cent. ; bassorine or racanthine, 33'1 ; water, 11 -1 ; inorganic tter, 2'5. Starch is detected in very small rnntity in the bassorine. From the ultimate lalysis the same chemist deduced the formula s. The uses of gum tragacanth are imilar to those of gum arabic. Apothecaries iploy it to give adhesiveness to the ingredi- its of pills, and confectioners apply it with a lilar object to the materials of lozenges, rum of Bassorah, from Bassorah near the head the Persian gulf, is of this class of gums, and irnishes the name for the peculiar principle ley contain. CHERRY-TREE GUM, including in lis name the exudations of the peach, plum, id other kindred trees, is an inferior quality gum, somewhat like gum arabic, and con- istingof a portion soluble in cold water, which arabine, and a portion insoluble, which is the rinciple named by M. Gu6rin-Varry cerasine. ?or gum kino, see KINO.) GUM MEZQUITE the product of the mezquite tree (prosopis mdulosci) of Texas and New Mexico, brought notice in 1854 by Dr. Shumard of the Inited States army. It is described as sim- ir in its properties to gum arabic, exuding rataneously from the tree, and concreting tears and lumps of variable sizes, semi- msparent, and of lemon white to dark iber shades of color. It is brittle and sily pulverized, and the fractured surfaces brilliant. From an ounce to 3 Ibs. has 3n obtained from a single tree, and more, no )ubt, by making incisions in the bark. The )ranches furnish a purer quality than the runk. The best time for collecting it is the itter part of August. The trees abound upon 'ie plains over regions thousands of miles in jxtent, and flourish luxuriantly in dry and ele- vated situations. If the gum could be easily >btained in large quantities, it would become an important commercial article ; but an abun- dant exudation takes place only in unusually dry seasons after an interval of several years. Specimens have been analyzed by Dr. Camp- bell Morfit with the following results : arabine, 84-967"; bassorine, 0-206 ; water, 11-640; inor- ganic matter, 3-000 ; impurities, 0-236 ; total, 100-049. Elementary composition: carbon, 44-706 per cent. ; oxygen, 48794 ; hydrogen, 6-500. It thus shows a close resemblance to gum arabic and gum Senegal in composition as well as in its physical and chemical properties. It is kept in the drug stores of the Mexican cities, and considerable quantities have been sent to San Francisco from the Mexican ports on the Pacific. This country receives its sup- plies of gums in great part through England. GUMBIMEff, a town of Prussia, capital of a district of the same name, in the province of East Prussia, on the Pissa, 68 m. E. of Ko- nigsberg; pop. in 1871, 9,085. The town, lying on both sides of the river, is regularly built, and contains three Protestant churches, a public library, a school of midwifery, a gym- nasium, and two hospitals. It has manufac- tories of woollen and linen cloth and hosiery, beer, and liquors, and a considerable trade in corn and cattle. Gumbinnen owes its pros- perity largely to the fact that it gave asylum to Protestants, chiefly from Salzburg, who fled thither from persecution about the year 1732. Previously it was but an insignificant village. GUMBO, a southern name, probably derived from the negroes, of a stew or soup, usually made of chicken, and thickened with the mu- cilaginous pods of the okra. When these can- not be obtained, sassafras pith or tapioca is used as a substitute. (See OKRA.) GUM RESINS, inspissated juices of certain plants, obtained by spontaneous exudation or from incisions purposely made. They consist of resin and gum, the proportions varying in the different varieties, and with these are com- monly associated essential oil, and other vege- table substances, as starch, bassorine, extrac- tive, &c. They are most of them hard and dry substances, brittle and opaque, rarely trans- lucent like the resins. Some that are semi- liquid and viscid, as the sagapenum and galba- num, become hard in very cold weather, and may then be pulverized. At a moderate heat these are sufficiently fluid to be strained through a cloth ; and all the gum resins may be thus strained and purified by first boiling them in water. They are partially soluble in water or in alcohol, and wholly so in a mixture of these. In water alone the gum dissolved holds for a time the finely divided resinous portion sus- pended, and thus emulsions are prepared for administering the substances in medicine, which is their principal use. Balsams are distinguished from gum resins by containing benzoic acid. The most important gum resins are described in separate articles, as aloes, ammoniac, asa- foetida, bdellium, euphorbium, galbanum, gam- boge, myrrh, sagapenum, scammony, &c.