Hi -- I believe my grandfather brought this back to our family from WWI, although he may have known it before that. It was a great song to sing on car trips, and we kids felt very daring singing about being drunk, and all those sneaky "-dam"s. Here's how we learned it:

Drunk last night, drunk the night before,
Gonna get drunk tonight like I've never been drunk before!
For when I'm drunk I'm as happy as can be
For I am a member of the souse family.

Now the souse family is the best family
That ever came over from old Germany!
There's the Amsterdam Dutch and the Rotterdam Dutch
The Pottsdam Dutch and the other damn Dutch.

Hooray for the Irish, they don't amount to mutch
But they're a damn sight better than the low-down Dutch.
Drink to the Irish, they're drunk.

My grandfather's family was English, and during WWI both the Germans and the Irish posed a danger, so maybe that's the source of the last verse.