KAT. ORDER. — LEGUMNOS^. " 151 



harvest, of the journey, and of the fair, the Moors of the desert Uve al- 

 most entirely upon it ; and experience has proved that six ounces are 

 sufficient for the support of an adult during twenty-four hours. 



Medical Properties and Uses. The characters g-enerally given of 

 gum as a vegetable pi'inciple, belong only to the gum-arabic, which is 

 transparent and colorless, easily I'educed to powder, without smell, 

 and of a slightly sweetish taste. The solution of gum in water con- 

 stitutes mucilage. It is thick and adhesive, and soon dries when ex- 

 posed to the air. Gum is also soluble in weak acids, but is totally in- 

 soluble in alcohol. Gum is very little disposed to spontaneous decom- 

 position. By oxygenizement with nitric it forms successively mucic, 

 malic, and oxalic acid; with oxymuriat acid it forms citric acid. By 

 exposure to heat it does not melt, but softens, swells, and becomes 

 charred. 



In medicine, gmn-arabic possesses the powers of mucilaginous 

 demulcent in a high degi'ee. It is useful in all cases where there 

 seems to be a natural deficiency of mucus in the intestinal canal. — 

 Dissolved in milk, barley-water, or almond emulsions, it removes tenes- 

 mus. It is useful in an irritable state of the respiratory passages, in 

 catan-h, hoarseness, and cough. For this purpose it may be either 

 administered in substance as a troche, or in a strong solution, and may 

 be combined with a little opium. It is also useful in salivation after 

 mercury, or in small pox. Externally it is applied in powder to bleed- 

 ing vessels of a small size as a stj^ptic, operating by glueing them up. 

 It is also used in solution as an injection in gonon-hcea. 



