From the folk song Oh! Susanna by Stephen Foster (presumably written in slave dialect):
De bullgine bust, de hoss ran off, I really thought I’d die; I shut my eyes to hold my bref—Susanna, dont you cry.
Sheet music from Duke University on Wikimedia Commons
Emphasis mine. What does this phrase mean? All searches of that phrase and its variations turn up lyrics to Oh! Susanna, which makes me wonder if this phrase is unique.
It doesn't mean anything. The lyrics are deliberate nonsense, full of contradictions.
Consider :
It rained all night the day I left, the weather it was dry;
The sun so hot I froze to death—Susanna, don’t you cry.
The weather is both rainy AND dry. A contradiction. The sun was hot, but the singer froze. Another contradiction.
I jumped aboard the telegraph and traveled down the river,
How is it possible to travel on a telegraph? It isn't possible, it's nonsense.
I shut my eyes to hold my breath
There is no connection between shutting eyes and holding breath. It's a non-sequitur. Another piece of nonsense. It doesn't mean anything, and that's the joke.
