“Would you read it to me?” he says, and sinks down into the chair, cradling his hand against his chest. I can see there are sores in his fingernails.

I do not have any feeling in my hands. I pick the envelope up by its corners and turn it over. The skin of his finger is still on the flap. I back away from the table. “I must find the doctor. It is an emergency.”

“You would not be able to find him,” he says. Blood oozes out of the tip of his finger and down over the blister in his fingernail. “He has gone up to the front.”

“What?” I say, backing and backing until I run into the blanket. “I cannot understand you.”

“He has gone up to the front,” he says, more slowly, and this time I can puzzle out the words, but they make no sense. How can the doctor be at the front? This is the front.

He pushes the candle toward me. “I order you to read me the letter.”

I do not have any feeling in my fingers. I open it from the top, tearing the letter almost in two. It is a long letter, full of equations and numbers, but the words are warped and blurred. “ ‘My Esteemed Colleague! I have read your paper with the greatest interest. I had not expected that one could formulate the exact solution of the problem so simply. The analytical treatment of the problem appears to me splendid. Next Thursday I will present the work with several explanatory words, to the Academy!’ ”

“Formulated so simply,” Schwarzschild says, as if he is in pain. “That is enough. Put the letter down. I will read the rest of it.”

I lay the letter on the table in front of him, and then I am running down the trench in the dark with the sound of the front all around me, roaring and shaking the ground. At the first turning, Müller grabs my arm and stops me. “What are you doing here?” I shout. “Go back! Go back!”

“Go back?” he says. “The front’s that way.” He points in the direction he came from. But the front is not that way. It is behind me, in the artillery headquarters. “I told you there would be a bombardment tonight. Did yousee the doctor? Did you give him the message? What did he say?”