5i8 



BOTANY AND PHARMACOGNOSY. 



the ROOT BARK is employed for the extraction of the alkaloids, 

 especially quinine. Owing to the fact that light influences the 

 production of quinine in the plant, it was customary to cover 

 the bark of the trunk with moss or other materials, and this 

 is known as " mossed bark." For some time the cultivators 

 removed the bark from the trunk in alternate strips, the de- 



FiG. 226. Quinine sulphate: long orthorhombic needles from a dilute alcoholic solution. 



nuded places being again covered, after which another layer 

 of bark develops that is very rich in alkaloids and is known 

 as " RENEWED BARK." The outcr bark, consisting of the periderm 

 layer and some of the cortex, is flattened out and allowed to dry 

 under pressure, and constitutes the "flat" (or Tambla) bark 

 (Fig. 226). 



Most of the cinchona bark of commerce is now obtained from 

 trees cultivated in Java. During the year 1902 some 600,000 

 kilos of cinchona bark were exported from this island alone. The 

 older methods of cultivation have been entirely replaced by the 

 selection of seeds from those plants that run high in alkaloids. 

 The yield and quality of alkaloids in the bark are improved by 

 hybridization of the best trees. 



