For the better part of an hour the wild brother ran by his side, whining softly.

Then he sat down, pointed his nose upward, and howled.

It was a mournful howl, and as Buck held steadily on his way he heard it grow faint and fainter until it was lost in the distance.
John Thornton was eating dinner when Buck dashed into camp and sprang upon him in a frenzy of affection, overturning him, scrambling upon him, licking his face, biting his hand--"playing the general tom-fool," as John Thornton characterized it, the while he shook Buck back and forth and cursed him lovingly.
For two days and nights Buck never left camp, never let Thornton out of his sight.

He followed him about at his work, watched him while he ate, saw him into his blankets at night and out of them in the morning.

But after two days the call in the forest began to sound more imperiously than ever.