"Sherlock!" John yelled. "Why is there a dead rat in the butter dish?"

"Just ignore it," Sherlock called from the living room. "And don't touch it."

John took a deep breath, willing himself to keep his cool. "Where is the butter?"

"How do you think the rat died?"

"Sherlock!" John gave up his calming efforts. The object of his annoyance came sauntering into the kitchen, scalpel in one gloved hand. He looked at John in mild perplexity. "What's the matter?"

John looked his flatmate in the eye. "You put a rat in the butter dish, where it apparently ate all the butter and died, leaving a deceased rodent in a food receptacle and you're asking me what the matter is."

Sherlock clapped him on the back with his scalpel-free hand. "Elementary! We'll make a detective of you yet."

He paused for a moment, then frowned. "No, we won't. But make yourself useful and head down to the store. We're out of butter."