Through the mesquite a horse moved deviously, following the crooked trail of least resistance. A man was in the saddle and in front of him a little boy nodding with sleep. The arm of the rider cradled the youngster against the lurches of the pony's gait. The owner of the arm looked down at the tired little bundle it was supporting. A wistful tenderness was in the leathery face. To the rest of the world he was a man of iron. To this wee bit of humanity he was a nurse, a playmate, a slave.