At least, he never had yielded to it.

Wherefore, in the autumns, he had attacked with gay zest such of Titus Romaine's swine as had found their way through the fence.
But, nowadays, there was little enough of gay zest about anything Laddie did.

For he was old;--very, very old.

He had passed the fourteenth milestone.

In other words, he was as old for a dog as is an octogenarian for a man.
Almost imperceptibly, but to his indignant annoyance, age had crept upon the big dog; gradually blurring his long clean lines; silvering his muzzle and eyebrows; flecking his burnished mahogany coat with stipples of silver; spreading to greater size the absurdly small white forepaws which were his one gross vanity; dulling a little the preternaturally keen hearing and narrowing the vision.
Yes, Lad was old.