Amusia, it's called, and it was the subject of the Frontiers programme on Radio 4 on Wednesday.

Seemingly between 2% and 5% of the population are amusic, meaning that they can't distinguish between the notes of the musical scale. You know the type yourself; perversely they're often the ones who love a singsong. As presenter Peter Evans put it, they would be unable to distinguish between Rachmaninoff playing Rachmaninoff and Les Dawson playing 'Roll Out The Barrel'. But if not having a note in your head has suddenly become all consequential, it hasn't taken the comedy out of it. Evans went to meet one man who is amusic, retired clergyman Jim Cross. Evans played a note for him on the piano, and Cross tried to sing it. He was flat by roughly a major third . . . not scandalous, you might say, but the more notes he tried to copy, the farther he got from the true note, and the more lovable he became. Cross has obviously been laughed at for this all his life, and has lost all vanity.

To show that amusia doesn't run in families, the programme also introduced us to the O'Neills in Co Tyrone. The whole family is musical, playing a variety of accordions and what have you, except for Terence, for whom music lessons were "some of the longest minutes I have ever spent". Terence was asked to submit to a musical listening test (you can do the same test online at www. delosis. com/listening /home. html), and judging by his first couple of answers, was going to get them all wrong.

Terence sounded resentful, exasperated . . . and not just in the way everybody north of the DundalkBallyshannon axis tends to sound exasperated. It'll be all those accordions going off around him. It has been said, after all, that a gentleman is someone who knows how to play the accordion and doesn't.

Now that the inability to distinguish musical notes has been given a name, can we do the same for those of us who cannot discriminate between different kinds of perfume? Is it a form of anosmia if a solution of chemicals in ethanol and water makes your airways constrict, and if all perfume just smells to you like 'sucker'? However, silly woman perfume is, when it comes to sheer noxiousness, no match for man perfume. Woman's Hour on Thursday asked whether aftershave is naff. It seems a reasonable question. The signs are that we're heading into a world where men all smell of L'eau D'issey but can't light fires.

Presenter Jenni Murray invited two men to speak about aftershave . . . Dan Cairns of the Sunday Times, who has pleasingly rugged ideas about it even though he writes for a poncey newspaper, and Nigel Hurlstone, professor of embroidery at Manchester Metropolitan University (yes you read that right) who loves it. They compared notes on perfume and aftershave, but it didn't take them long to start talking about musk.

Cairns complained that people's "raw animality" is masked by perfume. He doesn't like to get a mouthful of it when he kisses someone. Hurlstone said the secret is to put it on your head, not on your mouth, but Cairns said people wear it on their necks too, so when you kiss their neck you get "that tongue coating". For some reason this embarrassed Jenni Murray no end. She began to giggle hysterically. "This is getting a little too raw, " she said, and put a stop to it just when it was starting to get interesting.