From the sheet music at Johns Hopkins University (Levy Collection):


DAT'S HARMONY
Ziegfeld Follies of 1911
Words by Grant Clarke, music by Bert Williams, ©1911.

1. Mister Schubert's Serenade is grand.
I cert'ly love to hear a big brass band
Play Sousa's marches by the score,
An' I likes good op'ra; what is more,
Dat pleasing Melody in F
Is sho' some music—well, I guess,
But folks make a mistake, you see,
When dey say dat's all to harmony.

CHORUS: 'Cause when your best gal says you're her Marathon kid,
Dat's harmony.
When de wedding bells are ringing like dey never did,
Dat's harmony.
When you stand befo' de altar, han' in han',
De preacher says to her: "Are you taking dis man?"
She steps right up, says: " 'Deed I am"—
Man, dat's harmony!

2. Of modern music I adore
Dat barber's chord of Mister Jefferson Lord,
And dar's dat thing the Minor Strain;
It sho' has got one sweet refrain.
Dat Ev'ry Little Movement thing
Has got dose Streets of Cairo swing.
Don't think I can't appreciate
Dat music, 'cause it's great—

CHORUS: But when your wife says: "Come to your dinner, John,"
Dat's harmony.
When you jus' gets a whiff of what she's bringin' on,
Dat's harmony.
Wid all due credit to a big brass band,
De sweetest music in de land
Is when you hear de sizzle from de fryin' pan.
Man, dat's harmony!


Referenced music:
"(Mr. Jefferson, Lord,) Play That Barber Shop Chord" w. William Tracey; m. Lewis F. Muir (1910).
"That Minor Strain" w. Cecil Mack m. Ford Dabney (1910).
"Every Little Movement (Has a Meaning All Its Own)" w. Otto Hauerbach; m. Karl L. Hoschna (1910).
"The Streets of Cairo, or, The Poor Little Country Maid" w. & m. James Thornton (1895).
"Melody in F [Op. 3 No. 1]" by Anton Rubenstein (1881)