Doc Track by Scent

Every one noted Doc was inexplicably missing from the city at times. These absences lasted several hours. Then Doc would reappear. He offered no explanation. Actually, he had been ranging the jungle sections of the Valley of the Vanished. He was seeking his father's murderer. He traveled, apelike, among the trees, or silent as a bronze shadow on the ground.

Near the lower end of the valley he found what his keen senses told him was the camp of his quarry. But it was a cold trail. The camp had been deserted some time. Doc tracked the killer a considerable distance. The scent ended at the trail out of the valley.

- The Man of Bronze (1933) Chapter 18