How Did the Fart Machine Come About?

In World War I, they had sneezing powder. And it didn't do you that much harm apart from it. It made you take off your gas mask and then they'd be able to get you all the other stuff. Fred Jarrow tried to record the sounds with his friend John Blackman in a recording studio after eating lots of fart-causing food. They said it didn't sound right. What did they use in the end for the sound? That's a synthesizer. Like my old Yamaha didn't have a fart button.