A quarter of an hour elapsed. Then Derek bestirred himself. It was not the thought that he was lying in a somewhat exposed position, and that a safer retreat in the bottom of the second crater was within a few yards, that urged him to move. It was the sudden realization that every second he was lying with an open wound in contact with the earth he was running the greatest possible risk of septic poisoning from the highly impure soil. He had known several cases where men with chilblains had knocked the open sores against the side of a trench, and the momentary contact with the septic soil had been sufficient to cause acute blood-poisoning, resulting, in several instances, in loss of a limb. On the other hand, the extreme velocity of a bullet generates heat to such a degree that the missile is sterilized before it hits a man, and, provided that no vital spot is touched, the chances of complications arising from a bullet-wound are very slight. With shell-wounds there is a difference. Minute particles of German shells frequently cause slight wounds that, unless carefully treated, become septic. Derek freely admitted to himself that he "had the wind up" over the possibilities of tetanus. Even as he resumed his tedious crawl he incautiously showed the top of his head above the frail cover afforded by the ridge. The Huns, quick to perceive something in motion, swept the spot with their machine-guns. As a result Daventry ducked, but not before there were three or four bullet-rents in his leather flying-cap, while his triplex goggles, which he had pushed back just before he had been hit, were cut away by a piece of metal. Into the second crater he dropped, his legs buried above the knees of his fleece-lined flying-boots in the soft soil. Here he was relatively safe. He sat up and took stock of his surroundings: a circular sloping wall of debris descending to a pool of stagnant water eleven feet below the ordinary ground level. Here and there were coils of rusty barbed wire and the remains of calcined posts, while a Hun's "Dolly Varden" tin hat, sporting a bullet-hole front and back, and a battered dixie, alone served to break the monotony of the limited expanse of landscape.