In an effort to introduce a shaft of sunlight into a particularly gloomy conversation, I recently asked a gardening acquaintance of mine to explain the difference between a slug and a snail.

For the next twelve minutes and seven seconds, this horticultural monomaniac held forth on the most minute and inconsequential differences between gastropod molluscs with rudimentary or no shells and gastropod molluscs with well developed spiral or whorled shells. When he finally ran out of breath, I swallowed hard, took three precautionary steps backwards, and told him that a slug is a snail that can't afford a mortgage.

Instead of smiling as I had done when I had first unearthed this daft definition in a dog-eared copy of 'The Readers Digest' (dentist's waiting room edition), he ground his dentures together, cracked his calloused knuckles, and growled so raucously that the button almost exploded from his collar.

He went on to catalogue in some detail the manifold acts of vandalism perpetrated by these 'horticultural thugs' who, he said, spend their entire daylight hours skulking plumply under stones, ruminating darkly on last night's grim destruction and this night's planned assaults.

He proceeded to ridicule the 'green-wellied wimps' who nightly sprinkle little handfuls of slug pellets around vulnerable flowers and vegetables; and the poor drunkard who meanders home each night clutching a bottle of beer with which to entice and drown the occasional slug foolish enough to mistake his little beer traps for hospitality vats.

'I have suffered enough from the same blasted slugs over the years without starting to buy drink for them,' he said. 'There's only one answer to those brutes...all out military action!'

His eyes grew incandescent with malevolent glee as he described his nightly sorties into the flowerbeds and lettuce patches where, armed with a commando style torch and a jumbo-sized barrel of table salt, he would venture forth in search of the enemy.....a lethal avalanche of sodium chloride cascading inexorably on the masticating molluscs