236 PLANTS AND MAN 



shipment. As shortly before use as possible, the coffee "beans" — 

 in reality the seeds — are roasted, a process in which the aroma, 

 flavor, and color of the final product is determined. Different 

 varieties of coff'ee require difl'erent temperatures and times of 

 roasting. The content of caff'eine, which is the stimulating sub- 

 stance found in coffee and tea, varies around 1% in roasted 

 coffee. The flavor and aroma are due to the presence of an essen- 

 tial oil, in addition to which coffee contains very small amounts of 

 glucose, dextrin, proteins, and a fatty oil. The food value of coffee 

 is negligible, hence reducing diets permit its use, without sugar 

 and cream. 



Coffee, which constitutes the chief source of income of the 

 Brazilian people, like all of man's crops, suffers from diseases and 

 insect pests, as well as from overproduction and low prices. The 

 latter have caused much trouble in recent years, surplus coffee 

 having been dumped into the ocean, and used as fuels in the 

 producing regions. For almost fifty years the island of Ceylon was 

 an important producer of coffee, until a plant disease in the form 

 of a leaf rust (see Chapter 25) ruined the industry. 



Tea, although not furnishing as valuable a commercial crop 

 as coffee, is used by more people — over one-half the world's 

 population being accustomed to its beverage use. The tea plant 

 is a small evergreen tree or shrub three to four feet high; it was 

 originally native to China or India, but is now grown widely in 

 tropical or hot temperate regions. The lance-shaped leaves have a 

 toothed margin and bear white or pink flowers {fi^. 168) n their 

 axils. Since leaves are the desired product, tea plants are con- 

 stantly pruned back in order to stimulate the growth of new leaf 

 bearing shoots. Methods of cultivation of the tea plant vary with 

 the particular variety (of which there are a thousand or more 

 known) and the location, but all varieties require a very heavy 

 yearly rainfall for proper growth. A great diversity of lands are 

 used for tea culture, varying in altitude from sea level to five 

 thousand feet, often including land that is unsuited to other types 

 of agriculture. They range in extent from the small tea farms of 

 China to the great plantations of Ceylon. 



