MCCOY: (scanning him) Heartbeat is all wrong. His body temperature is. Jim, this man is a Klingon.
BARIS: A Klingon?
KIRK: I wonder what Starfleet Command will say about that. What about the grain, Bones?
MCCOY: Oh, yes. It was poisoned.
BARIS: Poisoned?
MCCOY: Yes. It's been impregnated with a virus. The virus turns into an inert material in the bloodstream. The more the organism eats, the more inert matter is built up. So after two or three days, they reached a point where they couldn't take in enough nourishment to survive.
KIRK: They starved to death. In a storage compartment full of grain, they starved to death.
MCCOY: That is essentially it.
KIRK: Mister Darvin, are you going to talk?
DARVIN: I have nothing to say. (Kirk thrusts the tribbles into his face) All right, I poisoned the grain! Take them away.
KIRK: And the tribbles had nothing to do with it?
DARVIN: I don't know. I never saw one before in my life, and I hope I never see one of those fuzzy miserable things again.
BARIS: I'm certain that can be arranged, Darvin. Guards? If you'll excuse me, Captain.
(Baris leaves with the security guards and Darvin.)
KIRK: Captain Koloth. About that apology.
KOLOTH: Yes?
KIRK: You have six hours to get your ship out of Federation territory.