MEDICINE SHOWS

A feature of life in the rural, mountain, and backwoods areas of the U.S.A., the so-called "physick" wagon was a familiar sight as late as the 1930s. 

Many a black and Country performer served his apprenticeship working to help a quack sell his medicines to unsuspecting people. 

The "doctor" used song and dance men to attract and hold a crowd; in addition, some of the performers helped mix the "medicines" and sell them. 

Arnold Shaw - American Dictionary of Pop / Rock.