Medicine: Doctor Calling. Over.

Voice: I've got a very delicate baby boy up here, doctor. Ten months old. Has a severe cold and 102.6 temperature under the arm. I hesitate to give him anything. Over.

Doctor: Doesn't look like measles, does it? No rash? Over.

Voice: Negative. I checked that. Over.

Doctor: O.K., use one of the oral medicines. Try triple sulfa. Give him plenty of fluids and two grains of aspirin every four hours. Call me in three days. Out.

The short-wave radio voice belonged to an Alaskan schoolteacher doubling as practical nurse in the remote hamlet of Marshall on the Yukon River. The doctor was William Henry...