In the poem "Dulce et Decorum Est" by Wilfred Owen, what is the condition of the gassed soldier after he was thrown in a wagon?

The gassed soldier serves as both a refutation of and antidote to the lines quoted in the title of this poem, taken from the writings of Horace, a Roman poet:  “dulce et decorum est pro patria mori.” Meaning, It is sweet and glorious to die for one’s country.  In Owen’s poem we have proof that it is indeed neither sweet nor glorious to suffer as the soldier in the wagon suffers, for one’s country or not.  If the reader could “watch the white eyes writhing in his face,/His hanging face, like the devil’s sick of sin,” he or she would understand the folly of this ancient phrase.  The soldier’s face is slack and numb from the gas, only his eyes belying the intense, insufferable pain he is experiencing – this disconnect between the eyes and the face is a potent and distressing image.  In addition to this,

“at every jolt, the blood/Come[s] gargling from the froth-corrupted lungs,/Obscene as cancer….” 

The integrity of the soldier’s lungs has been compromised by the gas, and now he froths at the mouth with blood at each bump in the road.  The soldier is completely incapacitated, at the mercy of the movements of the wagon and the gas in his system; the other soldiers “flung him” bodily into the vehicle, because he was unable to control his own movements.

The soldier was suffering from the horrendous effects of chlorine gas, which the Germans used in WWI as a more powerful alternative to tear gas.  The chlorine was not always deadly, and the Allied forces soon discovered the intricacies of mitigating its effects, but exposure to the gas can cause intense damage to the eyes, nose, throat, and lungs, and in high concentrations it can cause death by asphyxiation.  We cannot be sure as to what fate the soldier in Owen’s poem is heading, but we do know that whatever the outcome, the road is torturous. 

Owen emphasizes the incomprehensible pain of the soldier by having the speaker assert that the reader could only imagine it “in some smothering dream;” the image is too gruesome for waking life, too horridly imaginative for conscious thought.  And if any one of us should think that war is glorious, or that death is glorious, no matter what ideal one might die for, the sobering truth is the opposite.  Is what this gassed soldier going through glorious?  No.  It is horrid.  And this truth must displace the propaganda of clueless ideals.