TAPIO'CA, a farinaceous substance, prepared in South America from two species of Janipha, Manihot utiltssima, or the bitter, and Manihot Aipi, the sweet, Cassada or Manioc plants. The chief dis tinction between them is that a " tough ligneous fibre or cord runs through the heart of the sweet Cassava root, of which the bitter is destitute." Though the bitter contains a highly acrid and poisonous juice, from which the sweet is exempt, yet the bitter is cultivated almost to the entire exclusion of the other, which is probably owing to the greater facility with which it can be ground or rasped into flour, owing to the absence of the ligneous centre. The poisonous principle of the hitter manioc is thought to be of the nature of hydrocyanic acid. It is easily dissipated or decomposed by heat or fermentation ; hence the flour becomes perfectly wholesome in the process of baking the cassava bread. The juice, after expression, may be inspissated by long boiling, or formed into a soup, with flesh and spices, called cassarepo, said to be powerfully antiseptic. By means of molasses it
can be fermented and converted into intoxicating drink.
The fecula, or flour, after the juice has been carefully expressed, having been washed, and dried in the air without heat, is termed snow-Acme in Brazil, moustache in the Antilles, and rypipa in Cayenne. This constitutes the Brazilian arrow-root of English commerce. When this fecula is prepared by drying on hot plates, it becomes granular, and is called tapioca. It occurs in irregular lumps or grains, and is partially soluble in cold water. The granules, diffused through water, and examined by the microscope, are of great uniformity of size, and smaller than those of arrow-root from the Marantas. Tapioca is very nutritious and easy of digestion, being free from all stimulating qualities. It is therefore very necessary to distinguish it from an artificial tapioca made with gum and potato starch, which is In larger granules, whiter, more =ally broken, and more soluble in cold water than the genuine.