This song slip in the Library of Congress may be it:


RUN, NIGGER, RUN!
OR THE M.P. 'LL CATCH YOU.

De sun am set—dis nigger am free,
De colored gals he goes to see;
I heard a voice cry, "Run, dad, fech you!
Run, nigger, run, or de M.P. 'll catch you!

Chorus and repeat.
Run, nigger, run, de M.P.'ll catch you!
Run, nigger, run, tum a du daddle da!

Spoken. — Oh! you ought to seen me dressed dat day. I had a pair ob dese United States gaiters, hem-stitched behind, made ober at Blackwell's Island; and den I had on dat pink snuff-colored coat, and den I had on dat green white satin vest, together wid a hickory mahogany cane, wid a gold brass feller on de bottom. Oh! dar wasnt room enough dat day for me. I knocked de people off of de side-walk, and some of de time I got knocked off; but I got dar at last, and rung de bell. She opened the door; then hung my hat up on the floor. I set down by her side about an hour, telling her dat I lubbed her, when all at once she swooned ober in de chair, and exclaimed, "Look dar!" Says I, Whar? when I looked ober toards the door, and there was a white mans face, peeping fro de crack ob the door; at the same time he exclaimed, What, Mr. Bones?

Run, nigger, run, &c.
Wid eyes erect, and head hanging down,
Like de sprightly hare before de hound,
Dis nigger streak it through de pasture,
Nigger run fast, white man run faster.

Spoken. — Well, I didn't zactly run; but I done some pretty tall walking. I went ober fences, fro fields, and I got drowned four times in the mud, an at last I got on the other side; an just as I passed the old corn crib, thar was a little boy come out from behind the crib, an he whispered in my ear, an told me to "What did he tell you to do, Mr. Bones?"

Run, nigger, run, &c.
And ober de fence, as slick as an eel,
Dis nigger jumped—all but his heel;
De white man caught dat fast you see,
And tied it tight around de tree.

Spoken. —Yes, just like all the niggers, the heel is the biggest part ob the foot, an' just as I jumped ober the fence, he coch me by the heel, an held me fast, an sez, "I got you now." Sez I, I dont know bout that; so he took an tied it three or four times 'round the tree, an' then I tought I was a goner, when all at once something fell out of the top of the tree, cut off my heel, an at the same time it exclaimed What, Mr. Bones?

Run, nigger, run, &c.
Dis nigger heard dat old whip crack,
But nebber stopped for to look back;
I started home as straight as a bee,
And left my heel tied round de tree.

Spoken. —Yes, there wur no time to stop an' look back then, kase I wur making bout a milemile an a halftwo milesthree miles ana halfor four miles to the minute. So ober the fence I went, knocked in the front door, upset the cook stove, spilt all the victuals ober the floor, scalded de old cook to deff, an knocked the old woman fro the front window ; den de old man got after me wid de broomstick, an ebery jump I took, he hollered out "What did he holler, Mr. Bones?"

Run, nigger, run, &c.


My *guess* is that "M.P." means "mounted patrol."