The mouth is where illness enters and misfortune exits

No matter how much we pretend to be a world-class city, the fact remains that where food hygiene and handling is concerned, Hong Kong ranks only slightly better than most developing states. I know first-hand because I live one floor above a Chinese restaurant. The kitchen's drains are perpetually blocked and I count, among my downstairs neighbours, several families of the biggest and meanest rats this side of the Shenzhen River. Eateries in 'posher' areas such as Central and Causeway Bay are similarly compromised. And don't get me started on the 'live' seafood restaurants in Lei Yue Mun and Aberdeen.

That dirty food makes one sick is obvious. But about 1,700 years ago, at a time when physical ailments were attributed to malevolent spirits in most parts of the world, a Chinese philosopher and man of letters, Fu Xuan (AD217-278), made this observation - beng chung hau yup ('illness enters through the mouth'). One of China's earliest rationalists and an atheist, Fu Xuan believed that human behaviour, natural phenomena, illnesses and so on could be explained by reason and logic alone. China would have been a different place today if the rationalism of Fu Xuan and his colleagues had been installed as the state ideology instead of Confucius' stultifying dogma.

Beng chung hau yup is usually followed by wo chung hau chut, meaning 'misfortune exits through the mouth'. Despite the apparent association, this refers not to the dodgy dinner violently heaved into a hastily grabbed plastic bag, but to the damage we do with our injudicious words.