=Geographical Distribution.=—Reference to the chart will show 3 markedly endemic centers for beriberi, one embracing Japan, a second the Dutch East Indies (Java, Borneo, Sumatra), and a third, involving the Eastern coast of Brazil. In somewhat less degree the disease prevails in India, Indo-China, Malay Peninsula, Eastern China, and the Philippine Islands. It is also found in the regions of the East and West Coasts of Africa, and was devastating to the laborers on the Congo railway. It has been reported from many parts of the world among coolies from Asiatic countries. A disease of similar nature has been noted in asylums in England and America. Beriberi occurred among the British soldiers in Mesopotamia during the recent war—more than 300 cases in 1915. It is interesting to note that scurvy, and not beriberi, occurred among the Indian troops in Mesopotamia at this time. There was no scurvy in the British troops. ETIOLOGY AND EPIDEMIOLOGY =Etiology.=—There is probably no disease about which there exist so many views as to etiology as with beriberi. Many of those formerly advanced are so negatived by recent investigations that it would seem hardly worth while to mention them. While the cause is still unsolved attention is at present almost exclusively directed to some deficiency of a neuritis-preventing substance in the dietary and such studies have in large part centered about the question of such deficiencies in certain kinds of rice. Reserving until the last the discussion of the rice theories we may briefly dismiss such views as those assigning bacterial or protozoal causes with the exception of those of Manson and Hamilton Wright. _Manson’s Theory._—Under conditions of overcrowding, filth, warmth, moisture and lack of ventilation, as would obtain in the forecastle of a ship carrying a native crew, the development of a hypothetical germ is favored. This germ in its growth gives off emanations which like alcohol act as toxins upon the peripheral nerves. The germ itself does not infect the patient. _Wright’s Theory._—According to this view a bacillus which was given off in the faeces was ingested and locating in the duodenal mucosa gave off a toxin similar to that of the diphtheria bacillus. Instead of developing its soluble toxin in the membrane of the region of the throat this action took place in the upper part of the small intestines. Of the bacterial causes may be mentioned: (1) The coccus of Pekelharing and Winckler. This organism was supposed to be short lived in the body and repeated infections were necessary to produce the disease. (2) Dangerfield held views somewhat similar to those of Pekelharing and thought a coccus in the alimentary canal the cause. (3) Isuzuki regarded a coccus isolated from the urine as the cause. (4) Okata and Kokubo thought a coccus obtained from the blood to be the infecting agent.