Talk:Blue comedy

The given etymology doesn't seem right to me. See GCIDE based on Webster's 1939.

2. Pale, without redness or glare, -- said of a flame; hence, of the colour of burning brimstone, betokening the presence of ghosts or devils; as, the candle burns blue; the air was blue with oaths.

Assuming that 'oath' in this case is the archaic term for profanity (which seems likely giving the reference to devils) we'd have a previous example of 'blue' referring to foul language; extension to risque or sexual content would be natural.