"Don't be ridiculous, Sherlock! What would I do with it, have it bronzed?"
"If you like."
"You could save someone's life with that, and in all honesty, if you- if you were to die..."
"We all die some day, John. It's called mortality; you must have encountered the concept in medical school."
"I know that, you daft wanker! On some far future day, if you were dead... I can't think of anything I'd rather know than that your heart is still beating. Whoever it's in."
"And leaving me your internal organs for posterity isn't?"
"You may have a point."
"I do. I know your heart belongs to me, you show me every day. And mine belongs to you, but you aren't getting it after I die."
"There's no need to pout!"