I've read up to page 690 of the nearly 900 page biography of Huey Long. At this point, he has become a U.S. Senator and is in conflict with FDR, which is showing in the home state.

But I want to go back (pp. 537-8), to where Mr. Long was organizing the race for his succession to governor of LA. Earl Long, as his brother and party organizer, thought the lieutenant governorship was his for the asking. His older brother disagreed. So the whole Long family took to the stump against each other, most aligned with Earl.

Mr. Williams writes this:

[Huey] would begin the story by describing a social gathering popular with rural Protestants -- an "all-day singing" at the church, with "dinner on the grounds." At such a meeting in Winnfield, he would continue, the mothers had laid their babies on a pallet under a tree during the dinner. As they were clearing the table, a violent storm suddenly broke. Each mother hastily collected her child. But there was one baby that nobody would claim, an ugly, squalling brat. Mrs. Long, unwilling to see the child abandoned, had taken it home and adopted it. "That was Earl."

So Huey Long said.