Summary
Star Trek: Deep Space Ninecontained a deep-cutStar Trek: The Original SeriesEaster egg from the episode “The Deadly Years”, but it ended up having a deeper meaning. InTOSseason 2, episode 12, an Enterprise away team is exposed to fatal radiation that triggers rapid aging. With scenes of theStar Trek: TOScastin old man make-up, and the countdown clock tension, “The Deadly Years” became a belovedTOSepisode. AsStar Trek: DS9was packed full of major and minor references toTOScanon, a nod to a classic episode like “The Deadly Years” is hardly surprising.
Writers like Ronald D. Moore grew up as fans ofStar Trek: The Original Series, and that greatly influenced many of the scripts they wrote in the 1990s. Many ofRonald D. Moore’sStar Trekepisodescontained references, big and small, to the continuity ofTOS. As well as helping to build connections between 1990s shows likeStar Trek: Deep Space NinetoTOScanon, these references were reflective of Moore’s obsessive fandom, as he reflected in theStar Trek: Deep Space Nine Companion:

“There’s a lot of references from the original series rattling around in my head, because I watched it fanatically as a kid. Somehow it’s easier to remember those references than the stuff I worked on a few years ago on TNG.”
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Dr. Bashir Used An Anti-Radiation Drug From Star Trek: TOS’ “Deadly Years” Episode
Bashir’s “Deadly Years” reference foreshadowed his next DS9 episode.
InStar Trek: Deep Space Nineseason 3, episode 17, “Visionary”, Chief O’Brien (Colm Meaney) is exposed to fatal radiation that allows him to jump through time. Although"Visionary" was written by John Shirley from a story by Ethan H. Calk, Ronald D. Moore did have some uncredited input into the final script. One of Moore’s additions to the script was Doctor Bashir (Alexander Siddig) using Hyronalin to treat O’Brien’s radiation poisoning. Hyronalin was first mentioned inStar Trek: The Original Seriesseason 2, episode 12, “The Deadly Years”, when Doctor McCoy (DeForest Kelley) discussed potential treatments for the effects of rapid-ageing radiation.
InDS9season 3, episode 18, “Distant Voices”, Bashir finds himself in a hallucinatory reality where he, like theTOScast, ages rapidly during a race against time to save the station and himself.

Ronald D. Moore’s insertion of Hyronalin into the “Visionary” script maintained a medical continuity betweenStar Trek: Deep Space NineandStar Trek: The Original Series. However, Doctor Bashir’s reference to “The Deadly Years” ended up being an unintentional, and purely coincidental, set-up for the next episode ofDS9, which was Bashir-centric. InDS9season 3, episode 18, “Distant Voices”, Bashir finds himself in a hallucinatory reality where he, like theTOScast, ages rapidly during a race against time to save the station and himself.
The old-age make-up in “Distant Voices” wonStar Trek: Deep Space Ninean Emmy for Outstanding Individual Achievement in Makeup for a Series, beatingStar Trek: Voyager’s “Faces”.

Other References To TOS' Anti-Radiation Drug In Star Trek
In reference toStar Trek: The Original Series, Ronald D. Moore told theStar Trek: Deep Space Nine Companionthat “it’s easier to remember those references than the stuff I worked on a few years ago on TNG.” He might have had a point, as he’s clearly forgotten thatStar Trek: The Next Generationused Hyronalin twice, first in “Final Mission”, when the crew of the USS Enterprise-D were exposed to radiation from a 300-year-old garbage scow, and again when Doctor Beverly Crusher (Gates McFadden) and Lieutenant Commander Geordi La Forge (LeVar Burton) were exposed to plasma fire in “Disaster”.
And it wasn’t justStar Trek: The Next GenerationandStar Trek:Deep Space Ninethat maintained continuity with Starfleet Medical’s anti-radiation treatments.Robert Picardo’s Doctorused Hyronalin inStar Trek: Voyagerseason 3, episode 22, “Real Life”. When Lieutenant Tom Paris (Robert Duncan McNeill) was exposed to radiation from an astral eddy, the EMH treated this poisoning with a combination of Hyronalin and Lectrazine, suggesting treatments were beginning to move on from what had been established duringStar Trek: The Original Series' “Deadly Years”.
