Can't you just imagine the scene if Mrs. Lincoln had the call of nature and nowhere to go!?!
In searching for information on the National Hotel, I clicked on one of my favorite websites about the Streets of Washington: http://www.streetsofwashington.com/2009/...hotel.html. No mention of toilet facilities, but interesting history.
Just realized that the whole page doesn't automatically show. Type in National Hotel in the Search bar to get the article.