Finally found it:

SO EARLY IN THE MORNING
(Trad. )

South Carolina's a sultry clime,
Where we used to work in the summer time,
Massa 'neath de shade would lay,
While we poor niggers toil'd all day.
So early in the morning,
So early in the morning,
So early in the morning,
Before de break of day.

Chorus:
So early in the morning,
So early in the morning,
So early in the morning,
Before de break of day.

When I was young I used to wait,
On massa's table lay de plate,
Pass de bottle when him dry,
Brush away de blue-tail'd fly.
So early in the morning,
So early in the morning,
So early in the morning,
Before de break of day.

Now massa's dead and gone to rest,
Of all de massas he war best;
I nebber see de like since I was born,
Miss him now he's dead and gone.
So early in the morning,
So early in the morning,
So early in the morning,
Before de break of day.


Notes: copied from The Scottish Students Song Book (6th edition 1897).
Arrangement by J Kenyon Lees, one of the editors of the songbook.
The repetition of the second half of the verse as a 'Chorus' is literal. I.e. the words are sung as the end of each verse by the soloist, or by a group singing the melody, and repeated by a Chorus in harmony.
NP