In the first line, "Bent double, like old beggars under sacks," readers can see the weariness of the soldiers, trudging tiredly on the war ground. Also, by comparing them to beggars, the soldiers were probably very dirty after fighting for so long. Think of a soldier staying in a battlefield, their uniforms, their faces will most likely be covered with dust, grime, or even blood.
In the second line of the poem, it says that the soldiers were “coughing like hags”. To understand this line, we first have to understand the meaning of a hag. A hag, in ancient folklore, is something like a witch and has a rather awful scratchy voice. To cough like a hag in this case, shows that the soldiers are coughing heavily. In other words, it’s probably the result of a soldier staying in an unhealthy, probably dusty environment for too long that their health starts to deteriorate.
For the first two lines of this poem, it gives readers an image that the soldiers are old and perhaps have been fighting for many years. It is ironic, because those who went to war, like Owen himself are young and healthy, but during the course of war, they aged. It also contrasts with the pictures of handsome, upright soldiers so much used in propagandas.
In the twelfth line, after being attacked by the gas bomb, the persona sees another soldier “flound’ring like a man in fire or lime”. The gas bomb being used is mustard gas. This is a substance used in chemical warfare. It reacts with water in the lungs to form a corrosive chemical which destroys the lungs. The man who flounders is too late in putting on his mask. Owen describes the symptoms shown by this man as the poison slowly kills him later in stanza four. Death caused by a gas bomb is painful, as we can see from line 12, the soldier is suffering as if he’s being burnt by fire or lime (a white chalky substance which can burn live tissue) as he