| Quote #4
Perrault grinned. Considering that the price of dogs had been boomed skyward by the unwonted demand, it was not an unfair sum for so fine an animal. The Canadian Government would be no loser, nor would its dispatches travel the slower. Perrault knew dogs, and when he looked at Buck he knew that he was one in a thousand-- "One in ten t'ousand," he commented mentally. (1.45)
Men who are well educated in the way of dogs can better recognize how valuable Buck is.
| Quote #5
But Buck possessed a quality that made for greatness--imagination. He fought by instinct, but he could fight by head as well. (3.41)
Buck is made valuable by his innate qualities.
| Quote #6
Highly as the dog-driver had forevalued Buck, with his two devils, he found, while the day was yet young, that he had undervalued. At a bound Buck took up the duties of leadership; and where judgment was required, and quick thinking and quick acting, he showed himself the superior even of Spitz, of whom François had never seen an equal. (4.14)
The more Buck adapts to his new environment, the more valuable he becomes to those around him.