ACACIA BARKS. 289 



to preserve its sap during the dry season, when its 

 roots cannot any longer obtain moisture." * 



A large proportion of this thorny bush, as we have 

 said, is usually composed of various kinds of trees 

 belonging to the Acacia tribe; and the intense heat 

 and drought causes a shrinkage of the bark, in conse- 

 quence of which cracks are formed, from which valu- 

 able gums exude and solidify. 



This, in fact, is the great gum-producing country. 

 Various species such as "Acacia Arabica, A. Vera, 

 A. Ehrenbergii, and A. Tortilis, yielding the well- 

 known gum Arabic" while "the Acacia Verek, A. 

 Seyal, and A. Adansonii, furnish a similar gum, 

 known as gum Senegal" also "the Acacia Catechu, 

 and several other species yield catechu by boiling 

 down the wood, and evaporating, so as to get an ex- 

 tract." f 



These species are for the most part natives of Ara- 

 bia, the East Indies, and Africa. Gum Arabic is col- 

 lected in Northern Africa, by the Arab traders, in 

 immense quantities. 



" It begins to flow at the beginning of the dry season, 

 which is generally about November, and the harvest lasts six 

 weeks, during which time the collectors live almost entirely 

 upon the gum, which is highly nutritious, six ounces of it 

 being sufficient to support a man for twenty-four hours. " 



In some parts of the country almost any amount of 

 it may be collected. Sir Samuel Baker describing its 



* Across the East African Glaciers or the First Ascent of the 

 Kilimanjaro, by Dr. Haas Meyer, pp. 67 8. (Translated from the 

 German by E. H. S. Calder, 1891). 



f Encycl. Brit. Vol i, p. 63 (Qth edit.). 



Smith's Dictionary of Economic Plants. 



VOL. I. IQ 



