The thesis pitched in Mindshock (Channel 4) — that transplanted hearts might, in some cases, carry with them to their new owners some of the personality traits of their donors — sounds a little implausible at first. Your scepticism isn’t doused when an American cardiologist like Dr Jack Copeland is wheeled out to tell you: “Basically, from a surgeon’s point of view, the heart is first and foremost — and perhaps last, also — a pump.”

On the other hand, if transplanted organs really can carry some essence of their previous owners, it could explain quite a lot, couldn’t it? Maybe Kevin Costner secretly inherited the heart of an earlier Hollywood ham; Victor Mature, say. And what about the ethical issues that such a theory throws up? How, for instance, would you resolve the dilemma if you discovered that you needed an organ transplant, and that such an organ donation was available only from George Galloway, opening up the possibility of your one day finding yourself kneeling on the floor in a red Lycra leotard, purring, and sipping imaginary milk from Rula Lenska’s open palm? Mindshock waits until almost the end of its film to let slip that only 5 to 10 per cent of heart transplant patients actually claim to exhibit the sort of personality changes the programme was parading. But these personality changes are pretty startling. The first woman in New England to receive a heart transplant, 20 years ago, recalls being asked by reporters a few days after the operation what she most wanted, and she replied: “I’d die for a beer right now.”

Well, that’s quite a weird verb to use when you’ve just been through a life-saving operation. But even weirder was the fact that the woman wasn’t a beer drinker. She began to sense she was “living with the presence of another inside me”. That sense swelled when she developed a novel taste for green peppers. For the first time, she stopped to buy some KFC chicken nuggets. Then a dream featured a young man by the name of “Tim L”. That turned out to be the first name, and the opening letter of the surname, of the donor from whom she had received her new heart and lungs. The donor drank beer, liked green peppers and was carrying some chicken nuggets when he died.

Another heart recipient became obsessed with classical music. This new passion collided with his peculiar earlier concern that — since his new heart was coming from a 17-year-old black youth — he might find himself incubating a taste for rap music. Only later did the man discover that the black youth was a classical violinist.

Then there’s the middle-aged man who, post-transplant, becomes very athletic: he takes up running and cycling. He later learns that his donor was a very fit Hollywood stunt man. The recipient has no doubt that he inherited his new interest in exercise along with his new heart. Does his cardiologist, Dr Jack Copeland, agree? Not really, no: “That’s his idea. I respect it . . . but as a surgeon I can’t accept that as a valid interpretation without some kind of proof.”

But some scientists now wonder if those references by poets and Tin Pan Alley lyricists to the heart as an almost sentient organ — a bit like Pascal’s heart, which “has its reasons, which reason knows nothing of” — are more than just sentimental metaphors that also happen to provide handy rhymes for art, part, smart, tart, dart, upstart, á la carte and Mozart.

These scientists believe there is enough evidence to suggest that the heart plays a role in sending messages to the brain; that the heart has its own unique type of intelligence. You can’t rule anything out, admits Professor Sir Magdi Yacoub, the heart surgeon. But he remains pretty unconvinced: “I’m very sceptical, because I know that this organ cannot generate ideas or memory in the sense we know.” That’s what he feels in his heart of hearts, at any rate.

In his heart of hearts Samuel Johnson must have enjoyed compiling his dictionary, since, although he defined a lexicographer as “a writer of dictionaries, a harmless drudge”, it was a challenge that happily engulfed his life. Richard Alwyn’s Samuel Johnson: The Dictionary Man (BBC Four), with Roger Ashton-Griffiths as an engaging Johnson, reminded us that Johnson’s idiosyncracies were not confined to his occasionally waspish definitions.

His selection of words worthy of definition was also intriguing. He did not, for instance, include the words “blonde”; or “port”, as a drink; or “banknote”. But he did find room for “retromingency”, which means urinating backwards.

It’s something that hares do, apparently. If Nature can find a good reason for hares weeing to the rear, then who’s to say Nature can’t produce hearts with memory?

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