It was this last that kept him thin.  When I took to the road, he travelled five miles to my every one, circling me widely, ranging far over the hills in mad dashes, or running straight and swiftly on the road, vanishing in a white fog of dust.  Walking slowly to avoid this, I would only meet him emerging from a fresh cloud of it with a glad tongue thrown out to the breeze.  Again, there were desperate plunges into wayside underbrush or down steep ravines, whence I would hear rapid splashing through a hidden stream and short, plaintive cries to tell that that wonderful, unseen wood-presence of a thousand provoking scents had once more cunningly evaded him.

Also did he love to swim stoutly across a field of growing wheat, his head alone showing above the green waves.  And if the wheat were tall, he still braved it—­lost to sight at the bottom.  Then one might observe the mystery of a furrow ploughing itself swiftly across the billows without visible agency.

When I do not walk, to give countenance to his running, he has a game of his own.  He plays it with an ancient fur cap that he keeps conveniently stored.  The cap represents a prey of considerable dignity which must be sprung upon and shaken again and again until it is finally disabled.  Then it is to be seized by implacable jaws and swiftly run with about the yard in a feverish pretence that enemies wish to ravish it from its captor.  Any chance observer is implored to humor this pretence, and upon his compliance he is fled from madly, or perhaps turned upon and growled at most directly, if he show signs of losing interest in the game.

This ceaseless motion, with its attendant nervous strains, has prevented any accumulation of flesh, and explains the name of Slim Jim affixed to him by my namesake.

Jim consented now to rest for a moment at my feet, though at a loss to know how I could be calm amid so many exciting smells.  I promised him as he lay there that he should never be compelled to learn any but the fewest facts necessary to make him as harmless as he was happy; chiefly not to bark at old ladies and babies, no matter how threatening their aspect, as they passed our house.  A few things he had already learned—­to avoid fences of the barbed wire, to respect the big cat from across the way who sometimes called and treated him with watchful disdain, and not to chew a baby robin if by any chance he caught one.  This last had been a hard lesson, his first contact with a problem only a few days younger than Eden itself.  It came to his understanding, however, that if you mouth a helpless baby robin, a hand or a stick falls upon you hurtfully, even if you evade it for the moment and seclude yourself under a porch until it would seem that so trifling an occurrence must have been utterly forgotten.  This was the one big sin—­sin, to the best of our knowledge, being obedience to any natural desire, the satisfaction of which is unaccountably followed by pain.