CASSAVA, the farinaceous root of two plants of the spurge family (Euphorbiaceae, q.v.), the bitter cassava, Alanihot rdtilissima, and the sweet cassava, M. Aipi, both important sources Df food starches. They are herbaceous or semi-shrubby perennials with very large fleshy, cylindrical, tapering roots as much as 3f t. long and 6 to gin. in diameter, and filled with milky juice. The slender stems, 5 to 9f t. high, bear large spreading long-stalked leaves, with the blade divided nearly to the base into three to seven long narrow segments. The plants are probably natives of South America, but the bitter cassava, which is the more impor tant of the two in an economic sense, has been introduced into most tropical regions, and is ex tensively cultivated in west trop ical Africa and the Malay Archi pelago, from which, as well as from Brazil and other South American States, its starch in the form of tapioca is a staple article of export. The sap of the bitter cassava root contains hydrocy anic acid, and the root, being therefore highly poisonous, can not be eaten in a fresh condition; while on the other hand the sweet cassava is perfectly innocuous, and is employed as a table vege table. Exposure to heat dissi pates the poisonous principle, and the concentrated juice is in that state used as a basis of cas- CASSAVA, A TROPICAL PLANT,