FOREST TREES AND PRODUCTS OF THE TROPICS 221 
world. Several species reach an enormous height, 
and grow with wonderful rapidity. It is generally 
believed that in swampy districts these trees prevent 
fever. Certain species consume large amounts of 
water, and thus drain the soil, while others grow in 
dry regions. They yield an oil which is used for 
many purposes. 
Tropical forests produce numerous dyewoods, one 
of the most important of which is Brazil-wood. The 
word ‘“‘ Brazil”? means dyewood. 
Another valuable dyewood is called camwood. 
This material is shipped in large quantities from 
Western Africa to England for the same purposes as 
Brazil-wood. 
Another important dyewood is logwood. Its sci- 
entific name is Hamatoxylon campechianum, which 
translated means “ redwood from Campechy.” It is 
common in the West Indies, Central America, and 
Mexico, and is shipped in large quantities to New 
York. 
An interesting tropical tree is the gamboge-tree. 
Gamboge is a yellow dye and water-color. The word 
is a corruption or change of the name “ Camboja,” 
which is Cambodia in India, whence it comes. A 
spiral incision is cut half-way round the tree, and 
at the end a joint of bamboo is placed ready to re- 
ceive the juice. When the joint is full it is heated, 
