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578 admission -rate among the native troops for dysentery was 43.8 per thousand, whereas in the European troops it was only 28.6; and in every hundred deaths in the native army 4.7 were from dysentery, against only 3.8 in the European army.*

3. European women in the tropics, though quite as subject to dysentery as European men, rarely suffer from liver abscess; children hardly ever.

4. The rarity of liver abscess in temperate climates. Predisposing conditions.— The foregoing considerations seem to indicate that for the production of liver abscess at least two things are necessary— a predisposing cause and an exciting cause. Dysentery is certainly not always and alone both the exciting and the predisposing cause. Were this so, native soldiers and European women and children in India would suffer as frequently from liver abscess as do European males there. Some additional factor evidently complicates the problem.

As liver abscess is developed principally in tropical climates and in European visitors there, and much more rarely in the native, it would seem that tropical conditions in those unaccustomed to them are in some way bound up with this predisposing element; and as liver abscess is rare in European women and children, it would seem that these conditions are in some way specially operative on European men. We have grounds, therefore, for concluding that, in addition to general tropical conditions, it must be the greater amount of exposure to which men, as compared with women and children, are subjected in the course of their business and amusements; or some other condition, especially that one which is relatively more common in men than in women and children, and