Just like de-natured alcohol. The (((bastards))) added deadly chemicals to the ethanol that was sold in hardware stores, this would keep the drunkards from buying it for a cheap buzz. If they drank the "new and improved" de-natured alcohol they would go blind and mad. Way to go Uncle Sam!
I'm guessing the turpentine from 125 years ago was different than what Home Depot sells today? I still wouldn't drink it, unless I was on a lighthouse and ran out of whiskey. Just add honey...