The mineral known as kryptonite was first officially introduced in the radio serial "The Adventures of Superman", in the story "The Meteor from Krypton", broadcast in June 1943."Only one arc in 1943 managed to transcend its era: "The Meteor from Krypton." Debuting on June 3, it marked the debut of kryptonite..."</ref> An apocryphal story claims that kryptonite was introduced to give Superman's voice actor, Bud Collyer, the possibility to take a vacation at a time when the radio serial was performed live. In an episode where Collyer would not be present to perform, Superman would be incapacitated by kryptonite, and a substitute voice actor would make groaning sounds. This tale was recounted by Julius Schwartz in his memoir.pg 132-133</ref> However, the historian Michael J. Hayde disputes this: in "The Meteor From Krypton", Superman is never exposed to kryptonite. If kryptonite allowed Collyer to take vacations, that was a fringe benefit discovered later. More likely, kryptonite was introduced as a plot device for Superman to discover his origin."Since Superman’s life isn’t threatened — the meteorite never leaves the doctor’s custody — it’s likely that Lowther’s primary intent was to create a means for Superman to discover his own origin."</ref>