When Elie is in the work camp, his foot swells from the cold, and a Jewish doctor tells him that he will operate on his foot. The doctor says that if Elie waits, he risks having an amputation. Elie is placed in the infirmary, where the man in the neighboring bed tells him to get well soon or face deportation to a worse fate. The doctor operates on Elie's foot while Elie is still awake. He tells Elie that the sole of his foot was filled with pus and that Elie, who fears his leg has been amputated, will instead be fine and will be walking in two weeks. Elie can benefit from two weeks of rest and slightly better food.

Later, after Buchenwald is liberated, Elie becomes ill from a kind of poison and also spends some time in a hospital. He does not elaborate on how he was poisoned. He lingers for two weeks between life and death. While recovering, he looks at himself in the mirror for the first time since he was in the ghetto and says of the corpse looking back at him, "The look in his eyes as he gazed at me has never left me."

After weeks of slaving in the brutal cold, Elie's right foot begins to swell, and he is soon unable to put it on the ground.  He goes to have it examined, and the doctor, a Jewish prisoner himself, declares that he must have an operation.  It is the doctor's opinion that if the operation is not performed immediately, Elie's toes, and perhaps his whole leg, will have to be amputated. 

Elie is put into the hospital, which is actually an almost pleasant place.  He is given a bed with sheets, and fed good bread and a soup that is thicker than that fed to the rest of the prisoners.  Elie is warned, however, by a skeletal Hungarian Jew who occupies a nearby bed, that he would do well to get out of the hospital at the soonest opportunity.  Selections occur more often in the hospital than they do on the outside; "Germany doesn't need sick Jews!"

The Jewish doctor performs the operation on Elie's foot the next day.  Elie is given no anesthetic, and must bear the pain of the procedure until he passes out.  When he comes to, the doctor tells him that the sole of his foot had been full of pus, and they had to open the foot to drain it; the operation had gone well, and Elie should be "completely recovered within two weeks (Chapter 5).

In Night, why does Elie have to go to the hospital?

In chapter five, Elie mentions that around the middle of January, his foot began to swell from the cold, and he started having trouble walking around. Elie's foot is infected, and the sole of his foot has begun to swell with puss. When Elie visits the camp's infirmary, a Jewish doctor informs him that they will have to operate on his foot immediately to avoid amputation. The next day, the doctor operates on Elie's foot. After the operation, Elie fears that they amputated his foot but the doctor informs him that he simply opened the sack full of puss on the sole of his foot during the surgery. The doctor also informs Elie that he will fully recover in two weeks. However, rumors begin to spread that the Russian army is rapidly approaching Buna and that prisoners will be evacuated. Elie fears that he will be killed by the Nazis if he remains in the infirmary and decides to evacuate the camp with his father and the other prisoners just two days after his surgery. After the war, Elie discovered that he would have been liberated by the Russians two days after the evacuation if he had decided to stay in the infirmary.

In Night, why does Elie have to go to the hospital?

By Chapter 5 of Night, Elie's foot, which begins simply swollen, is infected.  After consulting with the doctor, Elie is told that he needs an operation; without it, his foot will likely need to be amputated.  Elie goes to the concentration camp hospital.  On the bright side, there are better rations of food there.  On the other, there are also more frequent selections, and Elie fears that he will be selected without the opportunity to reunite with his father.

When Elie hears a rumor that the Russian army is close by and that the Germans intend to kill everyone in the hospital before surrendering, Elie sneaks out of the hospital and proceeds to meet up with his dad.  He feels that he has made the right move, although he finds out later that those who remained in the hospital were simply liberated several days later.

What places Elie in the infirmary in Night by Elie Wiesel?

While at the Buna work camp just after New Year's, 1945, Elie is stricken with a swollen foot caused by the cold of the bitter winter weather. When he goes to the infirmary, the kindly Jewish doctor tells him he needs an operation. The operation is successful but the doctor informs him he will need two weeks to recover. During this time he is in a bed next to an extremely emaciated man with dysentery who preaches doom and gloom. He keeps telling Elie that the selection is worse in the hospital and the Germans don't want any invalid Jews.

While Elie is resting in the hospital, news that the Russian army is closing in goes around the camp. Guns are heard nearby. The camp is ordered to be evacuated, but those in the infirmary are told they will stay behind. The man with dysentery tells Elie that they will all soon be shot and another man believes the camp will be mined. Elie has a difficult decision. He and his father can stay behind or be evacuated. The father leaves it up to Elie and he decides to leave. It is a fateful decision. Later, Elie discovers the infirmary was liberated by the Russians only a few days later. At Buchenwald, where they eventually end up, Elie's father dies.