First comes the ceremonial parade. A whole brigade swings into line and must prove that it can move as one man, as a perfect machine, without flaw or friction. One master mind directs every motion, and at the word of command thousands of feet are moving in exact time, wheeling, marching, maneuvering with a precision that proves the long months of patient practice. This finish of discipline and perfection of unity have their part to play in the winning of the battle raging at this moment up the line. Next the men must pass through the deadly gas chambers, to be ready to meet the attack of the enemy fully prepared. More fatal than the prussic acid which the Prussian has occasionally employed, is the deadly mixture of chlorine and phosgene, which has been most commonly used. In a gentle favoring wind it is put over invisible in the darkness, and if it catches the foe unprepared, can kill from ten to fifteen miles behind the lines. The mixture is squirted as a liquid from metal generators. It quickly forms a dense greenish yellow cloud of poison vapor, which floats away in the darkness. Its success must depend on the element of surprise, taking the enemy unprepared and choking him, awake or asleep, in the first few moments before the horns, gongs, and whistles send the alarm for miles behind the trenches. Recently a new so-called "mustard gas" has been used by the enemy with deadly effect, owing to the fact that it is both invisible and odorless. It is sent over in exploding shells, and sinks in a heavy invisible vapor about the sleeping men, creeping into their dugouts and trenches or enveloping them around the guns or in the shell holes. The effects do not manifest themselves for several hours. With stinging pain the man's eyes begin to close, and for a time he may go almost blind. He is then taken violently sick. The surface of the lungs and the entire body, especially where it is moist with perspiration, is burned. The skin may blister and come off. Many cases have proved fatal and many more suffer cruelly for weeks in hospital. With the men we attended a lecture on the nature of the various gases used by the enemy and the proper methods of meeting them. The lecture throughout was unconsciously couched almost in theological language. The instructor first disposed of what he called superstitious "heresies" concerning the gas, in order to prevent the men from having panic and "getting the wind up." There is a foolish rumor which says, "One breath and you are ruptured for life, or you fall dead the next morning," etc., etc., but he warns the men of its deadly nature and tells them they are to be saved from its fatal effects by knowing the truth.