Aging in Oz is comparable to death in Oz, in that both natural processes have been largely negated by the spell placed on Oz by the fairy queen Lurline. L. Frank Baum specifies this in the crucial passage on Lurline's spell in The Tin Woodman of Oz, Chapter 12: The failure of the anti-aging spell is the central premise of Paradox in Oz. The aging of children under the spell is discussed in the Oz short story "Four Views of General Jinjur." Eureka the kitten remains a kitten because she gets to Oz and stays there before she grows into a mature cat. (Eureka in Oz)