The simile in line one, "Bent double, like old beggars" not only says that they are tired, but that they are so tired they have been brought down to the level of beggars who have not slept in a bed for weeks on end. Also, the simile "coughing like hags" ,in line two, helps to depict the soldiers" poor health and depressed state of mind. Owen makes us picture the soldiers as ill, disturbed and utterly exhausted. He shows that this is not the government-projected stereotype of a soldier, in gleaming boots and crisp new uniform, but is the true illustration of the poor mental and physical state of the soldiers. By telling us that many of the platoon are barefoot, Owen gives us an idea of how awful the soldiers" journey already is; it then gets even worse. Owen tells us that the soldiers, although they must have been trained, still do not notice the deadly mustard gas shells being fired at them from behind; such is the extent of their exhaustion. .
In the second stanza, the pace of the narrative is increased. Owen describes the flurry of activity that takes place when it dawns on the platoon that they have the hazard of gas to deal with. He begins by writing "Gas, GAS!"( line 9), which instantly grabs the attention of the reader, and by writing it first in lower case and then again in capitals, he gives an impression of the rising alarm in the solders. Owen uses the expression "an ecstasy of fumbling"(line 9) to describe the soldiers trying desperately to get out and fit their gas masks, the word "ecstasy"(line 9) being used to give us the impression of the complete, all consuming panic which the soldiers feel when they notice the gas shells. This is effective because it is a complete contrast to the image of the soldiers before the shell, at first they were trudging on, "drunk with fatigue"(line 7), but are suddenly forced into an "ecstasy of fumbling"(line 9) by the falling of the gas shell.
