[Old Professer]

The methane comes mainly from the burps; farts are more likely to be hydrogen sulfide.

[Mr. Lucky]

Does it ever scare you, Professor, that you know that?

[TigersEye]

The methane comes mainly from the burps; farts are more likely to be hydrogen sulfide.

Errr, is hydrogen sulfide flammable? Because if it isn't I can Google up some strange pics to argue the point with you. ;^)