Now imagine instead of ordinary shell that a number of gas shell had been dropped into this busy centre. On a dark night, probably very muddy underfoot and with all the excitement of kicking mules, flares going up and anything from machine-gun bullets at long range to shell of every size dropping in or expected, things are difficult enough. But with the advent of the gas shell every man must get himself protected. It is now that the “hold the breath, and mask on in six seconds” stunt is going to be of value. With well-trained troops the losses from the gas may be negligible, and it is equally true that they will be heavy if the discipline is poor. But whether one way or the other it means that all the frightened horses and mules must next be fixed with their respirators and the work in hand must be proceeded with by everybody while wearing gas masks. This is the real test. If the men are well trained the carrying parties--perhaps with loads of barbed wire on their backs--will get away as before and proceed up the filthy communication trench to the front line; swearing probably, uncomfortable certainly, but safe. Similarly the drivers will be able to get their teams away from the gassed area as soon as they are unloaded, and the serving out of the supplies will go on as before, though at a reduced rate. But if the soldiers were not able to carry on in these terrific circumstances--could not wear masks for long periods and could not do anything in them--confusion would undoubtedly supervene and the work be brought to a standstill. If this happened the men in the front line next day would be short of rations, of ammunition, of wire. They would, in fact, be neutralised. It is attempted neutralisation of artillery and infantry by methods such as these, carried out over large selected areas and generally as a preface to an attack--either their own or ours--which constitutes the German “fire for effect.” The “harassing fire” is simply the same thing on a smaller scale and with no immediate tactical reason at the back of it except that of killing and general annoyance. As a rule a sudden burst of a few shell will be landed on some likely place, such as the entrance to a communication trench, a sunken road, a bridge or an observation post. These small shoots were always causing us a few casualties. There was no warning, or somebody was not quick enough, or did not get his respirator on, or took it off too soon. There would always be some reason--but in the end it would generally come down to something that the disciplinary thumbscrew could cure. It is almost unbelievable nowadays that at one time one of the chief sources of these constantly occurring casualties was shame-facedness at being seen in a mask. Men would not protect themselves until absolutely forced to do so, for fear others would regard them as being too easily frightened. This was especially the case with new comers, who did not want to drop in the estimation of the older hands.