[Sherlock nods and makes a mental note of it. He'd certainly have to experiment on himself, he'd need to get a few--hopefully disposable--electronic devices to work on.]

John, have you had a blood test yet? Is it even possible to draw blood? I'd like to have a look under a microscope, if you don't mind.

[He tried to be extra polite in order to get what he wanted, like he did to Molly when he wanted extra thumbs.]