On the fourth day the temperature began to rise; the fifth it was clear, and thirty degrees warmer.  His thermometer had gone to sixty below zero.  It was now thirty below.

It was the morning of the sixth day when he reached the thick fringe of stunted spruce that sheltered Peter God’s cabin.  He was half blinded.  The snow-filled blizzards cut his face until it was swollen and purple.  Twenty paces from Peter God’s cabin he stopped, and stared, and rubbed his eyes—­and rubbed them again—­as though not quite sure his vision was not playing him a trick.

A cry broke from his lips then.  Over Peter God’s door there was nailed a slender sapling, and at the end of that sapling there floated a tattered, windbeaten red rag.  It was the signal.  It was the one voice common to all the wilderness—­a warning to man, woman and child, white or red, that had come down through the centuries.  Peter God was down with the smallpox!

For a few moments the discovery stunned him.  Then he was filled with a chill, creeping horror.  Peter God was sick with the scourge.  Perhaps he was dying.  It might be—­that he was dead.  In spite of the terror of the thing ahead of him, he thought of Josephine.  If Peter God was dead—­

Above the low moaning of the wind in the spruce tops he cursed himself.  He had thought a crime, and he clenched his mittened hands as he stared at the one window of the cabin.  His eyes shifted upward.  In the air was a filmy, floating gray.  It was smoke coming from the chimney.  Peter God was not dead.

Something kept him from shouting Peter God’s name, that the trapper might come to the door.  He went to the window, and looked in.  For a few moments he could see nothing.  And then, dimly, he made out the cot against the wall.  And Peter God sat on the cot, hunched forward, his head in his hands.  With a quick breath Philip turned to the door, opened it, and entered the cabin.  Peter God staggered to his feet as the door opened.  His eyes were wild and filled with fever.

“You—­Curtis!” he cried huskily.  “My God, didn’t you see the flag?”

“Yes.”

Philip’s half-frozen features were smiling, and now he was holding out a hand from which he had drawn his mitten.

“Lucky I happened along just now, old man.  You’ve got it, eh?”

Peter God shrank back from the other’s outstretched hand.

“There’s time,” he cried, pointing to the door.

“Don’t breathe this air.  Get out.  I’m not bad yet—­but it’s smallpox, Curtis!”

“I know it,” said Philip, beginning to throw off his hood and coat.  “I’m not afraid of it.  I had a touch of it three years ago over on the Gray Buzzard, so I guess I’m immune.  Besides, I’ve come two thousand miles to see you, Peter God—­two thousand miles to bring you a letter from Josephine McCloud.”

For ten seconds Peter God stood tense and motionless.  Then he swayed forward.