What might be called the primary symbol in "In Another Country" are the machines used in rehabilitation of the soldier's injuries. To some, these machines symbolize the non-war related probability of the futility and ineffectiveness of routine in daily life: you may follow a routine expecting it to be productive but in reality it isn't and can't be.
To others, the machines and the routine they require and establish symbolize the unsquelched hope that life will continue to have value after the reality of the devastation of the war. Upon that hope, the soldier's follow the routine and even socialize afterward even though there is no connection between them other than the motions they go through.
Ernest Hemingway's "In Another Country" follows the story of an unnamed narrator, an ambulance corps member--presumed to be Nick Adams--serving in World War I in Milan. The narrator receives daily rehabilitation treatments at the hospital to heal his injured knee; these treatments are administered by "machines" the doctors claim are miraculous. The narrator spends his time hiding out from the townspeople, who hate the soldiers at the Cafe Cova; there, he is looked down upon by the other soldiers for his status as an American. The narrator also meets a wounded major who has experienced the sudden death of his wife and who is far more affected by this trauma than his physical injury.
The most important symbolic image within the story is arguably the machines; although they are propped up by the hospital staff as objects of hope for the wounded soldiers, they ultimately only represent the disappointment and despair that the soldiers are facing. While the machines may be capable of curing their physical ailments (although the soldiers are suspicious that they are not able to), they do nothing to relieve the soldiers from the far greater emotional wounds that they are facing. This disconnect contributes to the great sense of isolation and cynicism felt within the story.