Kill or be killed, eat or be eaten, was the law; and this mandate, down out of the depths of Time, he obeyed.
He was older than the days he had seen and the breaths he had drawn.

He linked the past with the present, and the eternity behind him throbbed through him in a mighty rhythm to which he swayed as the tides and seasons swayed.

He sat by John Thornton's fire, a broad-breasted dog, white-fanged and long-furred; but behind him were the shades of all manner of dogs, half-wolves and wild wolves, urgent and prompting, tasting the savor of the meat he ate, thirsting for the water he drank, scenting the wind with him, listening with him and telling him the sounds made by the wild life in the forest, dictating his moods, directing his actions, lying down to sleep with him when he lay down, and dreaming with him and beyond him and becoming themselves the stuff of his dreams.
So peremptorily did these shades beckon him, that each day mankind and the claims of mankind slipped farther from him.

Deep in the forest a call was sounding, and as often as he heard this call, mysteriously thrilling and luring, he felt compelled to turn his back upon the fire and the beaten earth around it, and to plunge into the forest, and on and on, he knew not where or why; nor did he wonder where or why, the call sounding imperiously, deep in the forest.

But as often as he gained the soft unbroken earth and the green shade, the love for John Thornton drew him back to the fire again.
Thornton alone held him.