It should be realised, however, that properly protected dugouts have given perfect immunity from the mustard gas as long as the protection has remained intact, and a great deal of attention is being paid to increasing the number of the protected shelters in order to give the men the necessary rest from wearing their respirators occasioned by the extensive use by the boche of his Yellow Cross Shell. In Nieuport a special gas patrol was instituted for going the round of the town to see that blanket protection of cellars and shelters was kept in good condition, as there was always a chance that they would not be well looked after or that the blankets had been taken down by some enterprising Tommy for his own personal use. Round about battery positions the most annoying feature of the mustard gas is the length of time it persists. In the shell holes it can at any rate be partly destroyed by sprinkling with chloride of lime. It is rather interesting to find that in some captured German instructions great secrecy was laid on the use of chloride of lime for getting rid of the effects of mustard gas. The boche kept boxes of chloride of lime in all positions where the gas shell were stored, and issued instructions to his own troops that “the use of chloride of lime for the protection of our own troops against Yellow Cross liquid must not become known to the enemy. Observation of the strictest secrecy is a matter of duty just as much now as it was previously. The troops will be thoroughly instructed in these precautionary measures, but nothing will be taught them as regards the nature or composition of the antidote employed.” During the present offensive the Germans have used very large quantities of mustard gas, generally for holding purposes and against our rear lines, battery positions, communications and reserves. This is kept up for many hours in order to wear out the patience of our fellows and weaken them for the coming assault. Strong points that the boche does not wish to attack are also swamped with the gas, and when Armentières were evacuated by the British, Yellow Cross liquid was actually running down the gutters. But in places that he intends to assault he will complete the mustard-gas bombardment against our troops some considerable time before he advances; otherwise his own troops would run into it and be forced to don their respirators. The quantities of shell used in this preparation are enormous and supplies of the mustard gas must have been accumulated during the winter to an unexpected extent and their manufacture proceeded with to full capacity.