Detailed instruction also should be given as to what men are to do during and after the gas attacks; for there are some forms of gas that do not appear to affect the individual at all, and then all of a sudden, when he begins to use his limbs, he drops dead from heart failure. Instruction on this subject must come from the medical and chemical experts who have made a close study of the effects of gas. Allied to gas is LIQUID FIRE. This fire is projected in long streams from the nozzles of pipes that come from a high pressure cylinder, sometimes placed in the bottom of the trench, and sometimes carried on the backs of special men. These globules of burning oil that are sent forth reach a distance of thirty or forty feet from the nozzle of the pipe. The effect of liquid fire is more terrible than words can tell, and it requires great bravery on the part of troops to have them advance in the face of these streams. Clouds of SMOKE as well as gas are used. One of the ruses that was adopted at the battle of Loos was to project smoke forward for a few minutes until the enemy should become quite used to it, and then send out streams and waves of gas to take him unawares. These are frightful methods of warfare which the Allies have had to turn to in order not to allow the enemy, from his violation of his pledged word, and contrary to the rules of warfare, to gain an unfair advantage. But there are many of us who believe that no other enemy than the Germans would have descended to these depths of infamy. CHAPTER X THE ATTACK--DEFENCE