In Hemingway's story "A Day's Wait," a little boy, confined to bed with influenza, is patiently and stoically waiting to die because he believes his temperature proves he is beyond hope. It isn't until late in the story that the boy's father, who is also the narrator, understands why his son is so fatalistic.
"About what time do you think I'm going to die?" he asked.
"You aren't going to die. What the matter with you?"
"Oh, yes, I am. I heard him say a hundred and two."
He had been waiting to die all day, ever since nine o'clock in the morning.
"You poor Schatz," I said. "Poor old Schatz. It's like miles and kilometers. You aren't going to die. That's a diffferent thermometer. On that thermometer thirty-seven is normal. On this kind it's ninety-eight."
A kilometer is much shorter than a mile. According to the American Heritage Dictionary a kilometer is about 0.62137 mile.
This incident was probably drawn from Hemingway's personal experience. He was a great admirer of courage, as shown in so many of his stories and novels, including "The Old Man and the Sea." He was undoubtedly proud of his son "Bumby" for exhibiting such "grace under pressure" at such an early age.