I liked the idea posted by one person that it might be a hearing aid. She might also have just been trying to warm her cold ear.
Here's a state of the art Acousticon Model 28 (Silver Seal Symphonic) Carbon Hearing Aid
Since the model 28 came out around Acousticon's 25th anniversary in 1928, it was also called the "Silver Seal Symphonic" or "Silver Anniversary". In honor of this, the microphone and volume control were inlaid with a fancy pattern