76 



POPULAR ECONOMIC BOTANY. 



when dissolved this is British gum^ which^ besides its other 

 applications, is of immense use in dressing muslin and crape 

 goods. Of potato starch and dextrine, as much as 300 

 tons have been imported from France, Holland, and Germany 

 in one year, but its importation is very uncertain. The 

 quantity manufactured in Great Britain is enormous; the 

 returns however include wheaten starch, and show that of 

 the two kinds of starch mentioned, not less than 20,000 

 tons, of the value of £460,000, are annually manufactured. 



Aerow-Eoot (West Indian), the produce of Maranta 

 arundinacea, (Nat. Ord. Marantacea^ (Plate XI. fig. 53.) 



This fecula is remarkably pure, and is in the form of a 

 fine white glistening powder mixed with small lumps, which 

 are however easily pulverized between the fingers ; its starchy 

 character is easily seen by the microscope, under which it is 

 seen to consist of small granules concentrically laminated ; 

 the rings are very fine, and gradually increase in size from an 

 extremely small one, which seems apparently to occupy the 

 apex, and has been named the hilum. West Indian arrow- 

 root resembles potato starch, but is of a yellowisli- instead 

 of a -white colour, and the individual granules are 

 less translucent. The fecula is not, as might be supposed 

 from the name^ made from the root, but from a peculiar un- 



