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550 countries than in others, is found throughout the greater part of the tropical and many parts of the sub- tropical world. It is especially common in South China, Manila, Cochin China, Java, the Straits Settlements, Ceylon, India, tropical Africa, the West Indies* (Hillary), and Porto Rico (Ashworth). Apparently it is most prevalent in those tropical countries in which prolonged high temperature is combined with a moist atmosphere. It is common, however, in certain sub-tropical countries, as North China and even in Japan— countries where, although the summer is hot and damp, the winter is dry and bracing.

Etiology.— Prolonged residence in the endemic area is, perhaps, the most potent predisposing influence; cases, however, do occur in which the disease shows itself after a residence of one or two years only. Exhausting diseases, particularly those involving the alimentary canal, as dysentery, hill diarrhœa, morning diarrhœa, hæmorrhoids and fistula, are apt to terminate in sprue. Frequent childbearing, miscarriages, uterine hæmorrhages, exhausting discharges, and prolonged lactation also predispose to the disease; so may syphilis, courses of mercury or of iodide of potassium, bad food, bad water, anxiety, chills, and so forth in fact, any depressing influence, particularly if it is combined with intestinal irritation. Malaria does not seem to be specially responsible. At one time Strongyloides intestinalis (Anguillula intestinalis), a parasite very common in the stools of cases of chronic intestinal flux, particularly in Cochin China, was put forward as the cause of the chronic entero-colitis (for the most part sprue) of that country. Subsequent investigations have disproved this. Like the anguillula, Amœba coli or Bacillus dysenteriœ may be present in the stools in these cases; but, similarly, they are in no way responsible for the disease. Neither has any bacterium, or fungus, or other micro-organism which can be regarded with any degree of certainty