Leonard McCoy is confronted with the unusual silicon-based Horta alien in "The Devil in the Dark" (1967), saying, "I'm a doctor, not a bricklayer." The line was used in "Terra Nova". Kelley himself parodied the phrase for a "Trivial Pursuit" commercial, in which the question is asked "How many chambers does a human heart have?" Kelley appears on screen and replies "How should I know? I'm an actor, not a doctor!". Leonard McCoy Dr. Leonard H. "Bones" McCoy is a character in the American science fiction franchise "Star Trek". First portrayed by DeForest Kelley in the , McCoy also appears in the
Star Trek: The Original Series show. "Star Trek"s first-season ratings would in earlier years likely have caused NBC to cancel the show. The network had pioneered research into viewers' demographic profiles in the early 1960s, however, and, by 1967, it and other networks increasingly considered such data when making decisions; for example, CBS temporarily cancelled "Gunsmoke" that year because it had too many older and too few younger viewers. Although Roddenberry later claimed that NBC was unaware of "Star Trek"s favorable demographics, awareness of "Star Trek"s "quality" audience is what likely caused the network to retain the show after the first and second seasons. NBC