I.] 



EUPHORBIACE^;. 



205 



used by barbarous African tribes to poison their weapons. 

 The milk of a species of Hevea, Brazilian trees, yields 

 the best Caoutchouc exported from Para. It flows from 

 wounds in the bark, and is allowed to dry over moulds of 

 clay, the clay being washed out when the " India-rubber" 

 is sufficiently stiffened. Upwards of 158,000 cwts. of 

 Caoutchouc were imported into the United Kingdom in 

 1877. It must be borne in mind, however, that this pro- 

 duct is afforded by several other plants besides Siphonia : 

 especially by a species of Fig (Ftcus) in India. 



Gutta-percha is the similar product of an Indian tree 

 belonging to an Order (Sapotaceas) not represented in 



Fie. 142. Pistillate flower of 



R'icinns communis. 



FIG. 143. Staminate flower 

 of same. 



Britain. Upwards of 26,000 cwts. of Gutta-percha were 

 imported in i'877. 



Cassava, or Mandiocca Meal, an important article of 

 food in the Tropics, especially of South America, is 

 afforded by species of Manihot. The juice of one of the 

 Cassava-producing species (M. utilissimci) is a virulent 

 poison : this is removed from the root by washing, after 

 it has been grated. Tapioca is the fine starch which 

 settles down from the water used to wash Cassava. It is 

 granulated upon hot plates. The roots of the Bitter 

 Cassava weigh from 30 Ibs. to 40 Ibs., and the crop is 



