314 



POPULAE ECONOMIC BOTANY. 



rarely imported, a considerable quantity being grown for 

 medicinal purposes in various parts of the kingdom. We 

 however receive from Italy very large quantities of the 

 extract of the root, either made into short sticks, and called 

 Spanish Liquorice, or Liquorice Juice ; or else in the form 

 of an extract run into boxes of about two hundredweights 

 each; the latter article is the purest. 560 tons were im- 

 ported in 1850. Much of this large quantity is used by 

 the brewers in the manufacture of porter. 



Camphor. — A peculiar vegetable principle contained in 

 many plants, but the Camphor of commerce is derived from 

 CampJiora officinarum (Nat. Ord. Laurace^e), (Plate XYL 

 fig. 85.) 



Camphor exists chiefly in the wood of the tree, and being 

 volatile, is easily distilled from it by means of heat, and is 

 condensed in an earthen receiver. The crude or unrefined 

 camphor of commerce is obtained from China and Batavia ; 

 it is in the form of a crystalline powder, of a dirty white 

 colour, and resembling some of the white varieties of un- 

 refined sugar ; it is refined by re-distillation. The imports 

 exceed 200 tons annually. 



Nux Vomica. — The seeds of Strychnos Nux-Yomica 

 (Nat. Ord. Apocynaced). (Plate XVI. fig. 86.) 



