At 7.30 a.m. (February 26th, 1917) the relief commenced, and in due course the companies were finding their way back to billets at Fleurbaix, feeling themselves twice the men they were but a few days before. They knew now what the real trenches were; previously their knowledge had been limited to those poor imitations at the Foresters Public-House at Aldershot. Before completing the impressions of our first tour in the line, we cannot omit one thing from our account of this sector; not that the phenomenon is peculiar to these trenches or any other particular sector--in fact, till the more persistent use of gas sounded their death knell, they were to be found everywhere, "they" being, of course, rats. Now at home, in small numbers and well under the control enforced by long-established civilization, rats present no particular terrors or inconvenience except, perhaps, to a sensitive female. But in the trenches, where food was abundant and engines of destruction, at least as far as rats were concerned, few, they waxed plentiful, and their audacity increased with their size and their numbers. Not content with running all over the duck-boards, and all but refusing to step aside and let you pass, they ran riot in your dug-out, gnawed your clothes, devoured your food, scampered all over you as you slept, and in one notorious case caused grave inconvenience to a Medical Officer by removing bodily his set of false teeth. In the front line they climbed on the sleeping soldier and gnawed through his haversack to reach his iron ration. In the "bivvy" they nibbled holes in a man's socks as he lay on the ground. In fact, so bold were they that you could fire two or three rounds at a rat and hit all round him before he would condescend to move at all, and then he would only twitch his whiskers and remove himself in a leisurely fashion to some less disturbed spot. The services of Mr. Browning's "Pied Piper" would have been invaluable to us. There were, to be sure, various trench cats and an occasional dog, but they had other and better means of subsistence and took little heed of the rats. So the latter flourished, and, though curious diseases broke out among them, their lot must have been a happy one till the gas shells began to fall in every sector, and then their numbers dwindled rapidly, and in many parts they "ceased to be," at any rate for the moment.