The bill in lemon is an effect in which a magician requests a currency note from a spectator and makes the note vanish, then proceeding to slice a lemon open to show the note inside.
While several variations of the effect exist, the common element is the presumed transport of a spectator's currency note into the lemon. In many cases the lemon is examined by an audience member before cutting to reveal the bill inside. To identify the note, the magician typically has the spectator sign it, note the serial number, or retain a corner torn from the bill. Many versions of the effect are designed to be presented on stage or as a "stand-up" performance, however some close-up presentations exist.
Because the bill is borrowed and the lemon is an everyday object known to have a solid peel, the effect is one of the most impossible effects in magic to an audience. A related variation of this effect is "card in orange", where a playing card, often signed by a spectator, is shown to have transported inside an orange. An older variation, "The Coin In Orange" is described in Professor Hoffmann's landmark book, Modern Magic (1876.)
The origin of the Bill In Lemon effect is credited to Emil Jarrow (1875-1959), who made it a feature of his vaudeville act during the first half of the twentieth century. Jarrow would borrow as many as three different bills from members of the audience, causing them to later reappear inside of the lemon. Other famous performers of the effect included T. Nelson Downs, Max Malini, Bob Haskell and Billy McComb among many others. Several modern magicians have presented their own versions of the effect, including Bill Malone, Doc Eason, and Michael Ammar.