The bladder fiddle (also known as bumbass or poispil) is a folk instrument used throughout Europe. The instrument was a simple large monochord made with a long stick, a thick gut string, and a pig's bladder. It is bowed with either a notched stick or a horsehair bow. It is known under different names; in Germany it was called the bumbass, in France the basse de Flandre, and in England simply a drone or "drone and string". In Germany sometimes a bell or cymbal was added to the top. In England it was used by traveling musicians.[1]
A related instrument was preserved amongst the Pennsylvania Dutch (German immigrant to the rural Eastern United States), and is known as a boom-ba.
The bumbass, lagerphone, and tromba marina connection - Jon Rose Web - Includes bumbass audio