After a while, the doctor comes out and says "I'm sorry Bill, but we have discovered you have a condition which only allows you another 6 weeks to live". 

"But Doctor" Bill replied "I feel great. I haven't felt better in years. This just can't be true. Isn't there anything I can do?" 

After a moment the doctor said "Well, you might start going down the street to that new health spa and take a mud bath every day". 

Excitedly Bill asked "And that will cure me?" 

"No" replied the doctor "but it will get you used to the dirt".