My daughters learned a version of this song last summer at camp and also my wife found a version in the materials she uses to teach music lessons on a volunteer basis at the local school. The latter is claimed to be a Swedish folk song.

The version my daughters sing, as well as I can remember it:

I'm a famous doctor, come from Germany,
Hugo Gallespie,
Here's my piano
Plink-a-plink-a-plink-a-plink,
plink-a-plink, plink-a-plink
Plink-a-plink-a-plink-a-plink,
plink-a-plink, Hey!

I'm a famous...Here's my viola
Vio-Vio-Vio-La,
Vio-la, Vio-La,
Vio-Vio-Vio-La,
Vio-la, HEY! Plink-a-plink-a-plink-a-plink,
plink-a-plink, plink-a-plink
Plink-a-plink-a-plink-a-plink,
plink-a-plink, Hey!

There are several more instruments but I don't remember them. The instrument part is repeated and builds after each verse.