All that can presently (August 2015) be gleaned about by internet searching is that J. Gart is the one-off composer of Chewin' the Rag (1934) published by Mills Music Publishers, New York, USA.
Surfers are welcome to contribute information about this composer.
This list is arranged in chronological order and contains 1 work by J. Gart.
It does not claim to be complete and represents only the number of items located.