This what you should do...

1. At the first sign of a cold, go to bed with a bottle of whisky and a hat.

2. Place the hat on the left-hand bedpost.

3. Take a drink of whisky and move the hat to the right-hand bedpost.

4. Take another drink and shift the hat back again.

5. Continue this until you drink the whisky but fail to move the hat.

6. By then, the cold is probably cured.