Erik Jan Hanussen, in an article in Die Andere Welt (October-November 1931 issue), discussed various magical hoaxes, fakes, and tricks he had encountered in his career as a stage magician. Of them, the most baffling to me is the "Living Gasometer" stunt:
One day a young man came to me and showed me an amazing experiment. He placed a big steel siphon supposedly filled with acetylene gas in front of me, attached a tube to it, opened the valves, and apparently pumped his stomach full of flammable gas. He took an ordinary gas hose, which was attached to a bunsen burner, and then he ignited it. The gas - that was supposedly coming out of his stomach - flared up with bright, brilliant flames. The same stunt allowed the young man to cook two fried eggs on a gas stove from the gas, issued from a hose in his mouth; the Wonder-man also ignited a lamp, using ribbed tubing that was several meters long.
I was enraptured and awed by the feat until I was let in on the trick. Before the experiment, the Gas-Man places a sponge that is generously soaked in gasoline in his mouth. The fumes that are produced in the mouth feed the various combustibles. The whole time I wondered why my Living Gasometer was always so silent before his production started; today I don't wonder any more.