While discussing the age degenerative radiation sickness that had affected all of the landing party of the USS Enterprise, except Pavel Chekov, Doctor Leonard McCoy recalled having once read a piece from ancient history that contained information on a potential cure. This early research, recorded just after the Atomic Age, was based on the effects of administering adrenaline as a treatment for radiation sickness, which he noted as being "highly promising," but was ultimately abandoned when hyronalin was discovered. (TOS: "The Deadly Years" )