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XLII] quickly heals spontaneously, a minute hole, large enough to admit an ordinary probe, can be seen. Sometimes, when the blister ruptures, the head of the worm is seen protruding from this hole; as a rule, however, at first the worm does not show. If now we douche the neighbourhood of the ulcer with a stream of cold water



expressed from a sponge and, as the water falls, watch the little hole in the centre of the erosion, we shall see in a few seconds a droplet of fluid—at first clear, later milky—well up through the hole and flow over the surface. Sometimes, instead of this fluid, a small, beautifully pellucid tube, about 1 mm. in diameter, doubtless the uterus of the worm prolapsed through her head parts, is projected through the hole in response to the stimulus of the cold