Mysterious fluid rendered 1930s intestines immune to broken glass

A secret fluid reported on in the pages of the June, 1931 ish of Modern Mechanix had the property of rendering your intestines "immune" to cuts from glass, allowing you to ingest any amount of broken crystalware with impunity.

EATING light bulbs, bottles and tumblers with relish is the amazing feat performed by "Professor" Paul Owen, of New York City. The secret of his performance lies in a fluid which he swallows to render his intestines immune to cuts by the glass.

Glass Eaten With Secret Fluid (Jun, 1931)