If you ever wondered exactly how much you poop every day, then this invention is for you: the human turd scale. Yes, you read that right: a scale that weighs your excrement.
United States patent 1493222 is for "A weighing device especially adapted for weighing feces as excreted." Simply put, the patent is for a toilet outfitted with a turd scale in the bowl. A person seats themselves on the toilet, does their "business," and just like stepping on a traditional scale, takes a deep breath and hopes the number that registers at the top of the toilet bowl does not betray the number they've been praying for.
InventorSpot has more: Link
I would think that it was a viable product due to all of the odd medical quackery in the early part of the century.
However, most of the patents filed by that individual, had to do with filtering solids.