=Definition.=—Beriberi is a food deficiency disease due to the absence from the dietary of a neuritis-preventing vitamine. It is particularly important among the people of the Orient whose diet is preponderatingly one of rice. In milling the grain the outer vitamine-containing layers are rubbed off and this polished rice, when the chief constituent of a dietary, is capable of causing, after a period of two or three months, a peripheral neuritis. This neuritis not only involves the nerves of the extremities but, as well, the pneumogastric, and it is the manifestation of cardiac disturbances which best differentiate this form of neuritis from those due to alcohol or arsenic. The disease is usually described under two types: (1) a wet or dropsical beriberi, in which the vasomotor nerves are affected with resultant general oedema and (2) a dry atrophic or paraplegic type, in which muscular palsies and atrophies are the leading features. Pathologically, we have a Wallerian degeneration of the peripheral nerves with possibly axonal degeneration of the cells of the neuron involved. =Synonyms.=—Neuritis Multiplex Endemica, Polyneuritis Endemica, Hydrops Asthmaticus. Japanese: Kakke. HISTORY AND GEOGRAPHICAL DISTRIBUTION =History.=—While modern knowledge of beriberi may be said to date from the writings of Bontius, in 1642, yet the disease is distinctly described by Chinese writers of the seventh century and treated in writings of the second century and possibly referred to in writings as ancient as B. C. 2697. It is probable that the disease described by Strabo as occurring in a Roman army while invading Arabia, in 24 B. C., was beriberi. While mention of the disease may be found in Japanese writings of the ninth century it is thought by Scheube that this relates to the disease in China and that beriberi first appeared in Japan about the eighteenth century. Bontius described the atrophic form of the disease, Rogers, in 1808, the serous effusions, and Marshall, in 1812, noted two types, barbiers, when the paralysis predominated, and beriberi, when the dyspnoea and oedema were leading features. In 1835 Malcolmson noted that cases of beriberi assumed the type of barbiers and vice versa, from this time the view has obtained that the two affections belong to one disease. The disease seems to have first made its appearance in Brazil in 1866. [Illustration: FIG. 82.—Geographical distribution of Beriberi.]