NOTES ON PLANTS, VEGETABLES, AND FRUITS. 419 



" Mandioc, Mandioca, or Maniva, Jatropha manihot, L. Eu- 

 phorbiaceae. A plant with wide-spreading branches, originally 

 from Africa, cultivated in India and in America, from the Straits 

 of Magellan to Florida. As food, it is to Brazil what wheat is to 

 Europeans and North Americans. The root is large, tuberous, 

 fleshy, white internally, and full of a white juice very acrid and 

 very poisonous. The leaves are alternate, divided in three, five, 

 or seven lanceolate lobes, deeply cut and pointed, rather sinuous 

 edges, dark green on the upper side and glaucous on the under 

 side. The male flowers are separated from the female, but both 

 exist on the same plant. 



"The root of the mandioc is that part of the plant which is 

 most important. Some roots attain a very considerable size, and 

 weigh as much as fifteen kilos (thirty pounds). The root is almost 

 entirely composed of starch, with the addition of a poisonous white 

 juice. This poison, which is very subject to change, appears to 

 be cyanhydric acid, or a substance easily turned into that acid. 

 However, it is found easy to deprive the mandioc root of its acid 

 poisonous quality, either by the action of heat, or by repeated 

 washings. The root then becomes a healthy, as it is also a uni- 

 versal, food. It is used for the preparation of farinha de mandioca 

 (mandioc flour), one of the most valuable articles of diet in use 

 among the Brazilians. The following is the process employed for 

 the production of farinha (pronounced f army a): 



" The root is well scraped with a knife, the paste is then reduced 

 by a vertical wheel, and next pressed to deprive it of the poisonous 

 juice. It is then roasted, which extracts the last remains of the 

 poisonous principle, and gives it that look of granulated white 

 flour which is seen at table. It is also called farinha de pao (wood 

 flour, or sawdust). 



" The water in which the paste of the mandioc has been washed 

 is left to deposit at the bottom of the vessels a white silt which 

 is very pure starch. This, when dried, is called tapioca, a very 

 delicate and nutritious food. 



" The juice of the root is a powerful poison. A small dose is 

 fatal to men and animals after producing vomiting and convulsions. 

 This poisonous principle of the mandioc is very volatile ; for if the 

 juice be exposed to the air, it loses its deleterious effects after 



