My late Mother, born: Dedham, Mass., 1910 used to sing this song to my brother and me, when we were kids in the '50's.

I do not know any name for the tune to which it is sung.
I recall the tune clearly, but I do not believe it was to the tune of "Feller From Fortune" as I noted by mistake in the post above.

My Horse Named Napoleon

I bought a horse and I named him Napoleon
all on account of his bony parts.
He was so thin you could see right through him,
his hair was as fine as the finest silk.

He'd been owned by an old Hambletonian,
known everywhere around these parts.
Hitched him to an old milk wagon,
taught him to halt when I hollered, "Milk!"

One fine morning we went riding
along came a feller in a rig so neat.
He he hollered out, "Yuh gosh darn Rueben,
let's have a race right down this street."

Well, off we started helter skelter,
we were goin' at a thunderin' pace.
Sure you're as a sinner I was comin' in a winner,
When the feller hollered "Milk!"... and I lost the race!