MANGBETTU (Monbuttu)  , a negroid people of Central Africa living to the south of the Niam-Niam in the Welle district of Belgian Congo . They number about a million . Their country is a table-land at an altitude of 2500 to 2800 ft . Despite its abundant animal life, luxuriant vegetation and rich crops of plantain and oil-palm, the Mangbettu have been some of the most inveterate cannibals in Africa; but since the Congo State established posts in the country (c . 1895) considerable efforts have been made to stamp out cannibalism . Physically the Mangbettu differ greatly from their negro neighbours . They are not so black and their faces are less negroid, many having quite aquiline noses . The beard, too, is fuller than in most negroes . They appear to have imposed their language and customs on the surrounding tribes, the Mundu, Abisanga, &c . Once a consider-able power, they have practically disappeared as far as the original stock is concerned; their language and culture, however, remain, maintained by their subjects, with whom they have to a large extent intermixed . The men wear bark cloth, the art of weaving being unknown, the women a simple loin cloth, often not that . Both sexes paint the body in elaborate designs .

As potters, sculptors, boatbuilders and masons the Mangbettu have had few rivals in Africa . Their huts, with pointed

roofs, were not only larger and better built, but were cleaner than those of their neighbours, and some of their more important buildings were of great size and exhibited some skill in architecture . See G . A . Schweinfurth, Heart of Africa (1874); W . Junker, Travels in Africa (189o) ; G . Casati, Ten Years in Equatoria (1891) . MANGEL-WURZEL, or field-beet, a variety of the common beet, known botanically as Beta vulgaris, var. macrorhiza . The name is German and means literally " root of scarcity." R . C . A . Prior (Popular Names of British Plants) says it was originally mangold, a word of doubtful meaning .

The so-called root consists of the much thickened

primary root together with the " hypocotyl," i.e. the original stem between the root and the seed-leaves . A transverse section of the root shows a similar structure to the beet, namely a series of concentric rings of firmer " woody " tissue alternating with rings of soft thin-walled parenchymatous " bast-tissue " which often has a crimson or yellowish tint . The root is a store of carbohydrate food-stuff in the form of sugar, which is formed in the first year of growth when the stem remains short and bears a rosette of large leaves .