The Movie That Possibly Inspired Bones' Classic Line On Star Trek

Among the reasons "Star Trek: The Original Series" was wildly popular — and continues to be, more than five decades after it first aired — is that its main cast was so instantly iconic. While William Shatner wasn't originally cast as the lead, he's so convincing as the debonair Captain Kirk that it feels like a role he was born to play. The same can be said for Leonard Nimoy's First Officer Spock, whose split-hand salute and pointy ears are the first thing many people call to mind when thinking of "Star Trek." But rounding out the trio was DeForest Kelley as the ship's doctor, Leonard "Bones" McCoy, whose constant cynicism and grousing was consistently a point of comedic relief.

McCoy is commonly remembered for his mad-lib catchphrase, "I'm a doctor, not a ...," a sentence always ended with whichever professional would be best suited to the task at hand. Although McCoy only uttered that malleable catchphrase a handful of times over the show's three seasons, it's lived on in popularity among "Star Trek" fans. Later "Star Trek" shows such as "The Next Generation" would birth similar catchphrases, such as Lieutenant Worf's (Michael Dorn) insistence on the norms of his Klingon culture with the motif, "A Klingon does not..."

However, solidified in cultural consciousness as Bone's catchphrase has become, it turns out that "Star Trek" may owe a debt of inspiration to an obscure source.

The origins of Leonard McCoy's iconic "I'm a doctor" catchphrase can most probably be traced back to the pulp detective film, "The Kennel Murder Case," which was released in 1933. The movie follows the investigation of an art collector murdered in a closed room. Along for the ride is one Doctor Doremus, played by Etienne Girardot. At several points throughout the movie, Doremus repeats the phrase, "I'm a doctor, not a detective," and in one instance he says, "I'm a doctor, not a magician" (via MeTV).

To be clear, nobody involved in the making of "Star Trek" has ever commented on this connection, but even "Star Trek" debuted more than 30 years after "The Kennel Murder Case," the similarity between McCoy and Doremus' catchphrases is unlikely to be a pure coincidence. When you add in the fact that both characters are doctors, it's easy to imagine how that catchphrase might have transferred from one character to the other. Perhaps the creator of "Star Trek," Gene Roddenberry, or even one of the show's other writers, saw "The Kennel Murder Case" and lifted Doremus's catchphrase from it, whether consciously or not. Regardless of how it happened, this does appear to be an example of art encouraging art, and a fascinating bit of "Star Trek" history.