CINCHONA 261 



growth proved to be richer in alkaloid than the natural bark of the 

 tree. This method of collecting the bark was largely adopted in India, 

 and was practised as follows : When the trees had reached a sufficient 

 age longitudinal incisions were made and alternate strips of bark about 

 4 or 5 cm. wide removed, leaving the intervening strips untouched. 

 The bark thus collected, which had not been subjected to any artificial 

 treatment, was known as ' natural bark.' The trunk was then covered 

 with moss, paper, straw, or other protecting material, and left to 

 replace the bark that had been stripped off. After a sufficient time 

 had elapsed the covering was removed, and the strips that had been left 

 untouched on the first occasion were then collected ; these had spent 

 part of their life under a protecting covering of moss, and were called 

 ' mossed ' bark. The tree was then again covered, and having been 

 deprived by the first two strippings of all its original bark, yielded, when 

 visited for the third time, bark that had been entirely developed under 

 the covering of moss to replace that which had been removed ; this 

 was ' renewed ' bark. 



The process is interesting but laborious and expensive. 



3. Shaving. By this modification of renewing, only a portion of the 

 bark is removed by shaving ; the remainder is left on as a protection to 

 the tree, which therefore does not require any covering of moss. 



Both these methods have been abandoned in favour of the following : 



4. Uprooting. The tree is allowed to grow until it has attained the 

 age at which it yields the maximum proportion of alkaloid. It is 

 then uprooted and the bark stripped from the root as well as from the 

 stem. By this means the valuable root-bark is secured, and the land 

 can then be re-planted. 



5. Coppicing. The tree is cut down to form stools, from which 

 adventitious shoots arise. These shoots yield handsome quills of bark, 

 and the method is specially suited for the production of the quilled 

 bark sold to the pharmacist. 



The bark is usually collected in the rainy season, when it separates 

 easily from the stem ; the colour of the inner surface of the fresh bark 

 is always pale, but by the action of the air a change in the tannin 

 rapidly takes place, and the bark assumes a brown or red colour. The 

 drying is usually effected in the sun, or frequently by artificial heat 

 in a specially constructed drying machine. For exportation, the bark 

 is usually pressed by hydraulic pressure into firm bales (as in Ceylon) 

 or stamped into sacks (as in Java) ; fine quills are carefully packed 

 in cases. 



Description. The commercial varieties of cinchona bark yielded 

 by the following species of Cinchona may be briefly described. 



1. C. Calisaya. The bark yielded by this species is sometimes called 

 ' yellow ' bark, but as this term is also applied to all cinchona barks 

 exhibiting a distinctly yellowish brown colour it is better to specify 



