240 POPULAE ECONOMIC BOTANY. 



Gum Arabic, Gum Senegal, and Gum Tragacanth. The 

 first, 



Gum Arabic, exudes from Acacia Arabica (Nat. Ord. 

 Leguminosa) and other species. 



The trees producing the varieties of this gum are abun- 

 dant in the East Indies, Egypt, Arabia, and Senegal. The 

 gum was well known to the ancients, and the acacia-tree 

 is supposed to be the Shittah and S/iittim-tree spoken of 

 in Scripture (Isaiah xii. 19, Exodus, Leviticus, and other 

 books). Most of the species of Acacia growing in warm 

 countries produce gum, and the different qualities of 

 gum are produced on the same species ; indeed gum arabic 

 appears to be a special product of the genus Acacia, and 

 the gum oozes out more or less pure from the same tree, 

 and from different species indiscriminately. It is gathered 

 without reference to quality, and afterwards sorted. Of that 

 called gum arabic, par excellence, there are three leading 

 sorts, — { Elect, 3 or the finest white gum ; the common gum 

 arabic, which is yellow and reddish ; and gum siftings, 

 which consist of the very small particles of both the other 

 sorts separated from the finer pieces by sifting. 



The following are the permanent varieties which are re- 

 cognized in commerce : — 



