216 TROPICAL AGRICULTURE 



superior as a source of quinin. The bark is harvested by prun- 

 ing and allowing the regrowth of suckers or by shaving the 

 bark in strips, removing only a portion at one time and cover- 

 ing the shaved strips. The renewed bark which grows from 

 these peeled strips is very rich in alkaloids. 



The value of quinin for the treatment of malaria was dis- 

 covered in 1638, and following upon this discovery the demand 

 for bark from wild trees increased rapidly. To show the enor- 

 mous interest in the cultivation of quinin it may be mentioned 

 that in 1887 Ceylon produced 16,000,000 pounds of bark, but 

 this country was unable to compete with Java under the low 

 prices of quinin and the production in Ceylon has therefore 

 fallen to about 110,000 pounds per year. Java is now one of 

 the chief quinin-producing countries. On the cinchona plan- 

 tations of Java it has been found that 2 pounds of bark per 

 tree per year, or about 600 pounds of dried bark per acre, is 

 a good average yield. Moreover, the cinchona planters of Java 

 have increased the percentage of alkaloid in the bark by a long 

 series of selections until they have obtained a strain of cin- 

 chona trees of which the bark contains 15 per cent, of alkaloids.' 



Cinchona trees have been found to grow satisfactorily in 

 the Philippines, Hawaii, and Porto Rico, but no commercial 

 production of this material has been developed within the terri- 

 tory of the United States. 



COCAINE 



Cocaine is an alkaloid which is derived from the leaves of 

 a shrub Erythroxylon coca, native to Peru and Bolivia. These 

 countries are still the chief source of supply. The shrub at- 

 tains a height of 6 to 8 feet and bears alternate, shiny, entire- 

 margined leaves and small white flowers. The shrub is much 

 branched and the bark of the branches and trunks is light gray 

 in color. This shrub thrives best in the humid valleys of the 

 Andes. It is cultivated to some extent in Bolivia, Guiana, and 

 western Brazil, but for the most part the leaves are obtained 



