I'm not sure what this phrase in this paragraph from "Call of the Wild" refers to.
His father, Elmo, a huge St. Bernard, had been the Judge’s inseparable companion, and Buck bid fair to follow in the way of his father. He was not so large—he weighed only one hundred and forty pounds—for his mother, Shep, had been a Scotch shepherd dog. Nevertheless, one hundred and forty pounds, to which was added the dignity that comes of good living and universal respect, enabled him to carry himself in right royal fashion. During the four years since his puppy-hood he had lived the life of a sated aristocrat; he had a fine pride in himself, was ever a trifle egotistical, as country gentlemen sometimes become because of their insular situation. But he had saved himself by not becoming a mere pampered house-dog. Hunting and kindred outdoor delights had kept down the fat and hardened his muscles; and to him, as to the cold-tubbing races, the love of water had been a tonic and a health preserver.