Remember that old assertion that you're supposed to drink eight glasses of water a day for good health? The so-called the 8x8 rule -- eight glasses of eight ounces -- is currently undergoing a classic case of myth-busting after an editorial in the Journal of the American Society for Nephrology (PDF) basically calls the idea an unfounded old wive's tale. Slate digs further, seeking the genesis of the 8x8 myth and comes up with evidence dating back to a 1796 German text, with various stops along the way, including this particularly amusing instance from 1900:
"By 1900, the New York Evangelist reported that a women's association on the Lower East Side was being instructed by a Dr. Vinton that one needed to ingest "at least eight glasses of water a day" and take "four times as much water as food." (Incidentally, the girls were also told that it was dangerous to get one's feet wet, that it wasn't good to "wear many skirts," and that their brains were "soft like jelly.")"