India it is certainly so associated in at least 30 per cent, of the total cases. Manifestly, the statistical aspect of this important question requires re-study in the light of more careful clinical and post-mortem observation.
Another important point yet to be definitely settled is the exact relationship in point of time of the dysentery to the liver abscess. In the great majority of cases the dysentery antedates the abscess. But many clinicians have held that in some instances the relationship is reversed; that in others the two diseases are from the commencement concurrent; whilst in others, again, hepatitis, presumably of a kind which may eventuate in abscess, alternates with active dysenteric symptoms. If the abscess antedate the dysentery, then the dysentery cannot be the cause of the abscess. On these grounds some pathologists have regarded liver abscess and dysentery as but different expressions of one morbid condition; reacting to some extent on each other, but not directly related the one to the other as cause and effect. Here, again, the latency as regards symptoms of some dysenteries has to be discounted in attempting to settle the question on clinical grounds only. All these discrepancies and differences of opinion have to be re-studied in the light of the acknowledged relationship of the amoeba to dysentery and to liver abscess.
Race, sex, and climate.— Besides its relationship to dysentery, there are several well-ascertained facts to be reckoned with before we can arrive at sound views on the subject of the etiology of liver abscess.
1. Though common in Europeans in the tropics, liver abscess is rare among the natives. Thus, in the native army of India the proportion of deaths from liver abscess to the total mortality in 1894 was only 0.6 per cent., whereas in the European army it was 7.4 per cent. Man for man, the relative liability of the European soldier and the native soldier was as 95.2 to 4.8.
2. This disproportion is in spite of the fact that the native is more liable to dysentery than the European. Thus, in 1894, in the Indian army the
