In case some of you haven’t seen this yet, this is Leonard Nimoy and DeForest Kelley reading a short story at a con.
About 2 minutes into this clip, Bones refers to when the Enterprise went down and places his hand over his heart sentimentally. Spock follows suit, but then Bones skips over to him and moves his hand down to his side – which is where the Vulcan heart should be.
Apparently De commented “I’m his doctor, I should know” or something to that effect, although it’s drowned out by the audience’s laughter in this video.
Happy birthday, De!