LEADING ARTICLE:Truth in old wives' tales?

Our friskier readers will be concerned to discover that recent research lends some weight to the old wives' tale that too much sex makes you go blind. Take a squint at this month's issue of Archives of Ophthalmology published by the American Medical Association. A study at Johns Hopkins University reveals that excessive sexual exertion may indeed be responsible for sudden, albeit temporary, visual impairment. The condition is known as valsalva retinopathy and has also been linked to prolonged vomiting.

This latest medical discovery should not surprise us too much. We now appreciate that some religious taboos, such as the Jewish ban on eating pork, have a sound scientific basis, unbeknown to those who originally forbade the practices.

It may therefore be time for scientists to review other sayings that have been dismissed lightly. They might start with the old belief that people who pull a funny face when the wind changes are stuck with the distortion. Could it be that there is a real danger? Does exposure to sudden blasts of cold air perhaps so traumatise nerve endings that paralysis is induced? One might ask, for example, whether there was a freak breeze when the rather drawn American comedienne Joan Rivers was doing her impression of The Scream by Eduard Munch?

There is also the warning all children know, but then forget as adults, namely that if you tell a lie your tongue will turn black. It is conceivable that the stress of maintaining a deceit has physiological consequences in the stomach, making bile rise to the mouth. Such revelation would certainly prove invaluable to the wives of adulterous husbands and voters on doorsteps. Instead of trying to catch out politicians, interviewers could simply ask them to stick out their tongues.

Plenty of theories from abroad may also warrant attention. The Romanian belief that a child born on Christmas Day will become a werewolf can probably be set aside. But the Poles offer more useful advice. They say that if you sing or whistle at the table you will marry a stupid person. Anecdotal evidence already gives some to support this theory. Michael Jackson and his wife Lisa-Marie Presley obviously like a tune before breakfast.

Certainly some old wives' tales deserve urgent attention. It has long been said that those whose eyebrows meet tend towards violence aggression. Useful information to John Major as he wanders Parliament this week and wonders who are the guilty MPs who voted against him yesterday.