Joe and Jim were out cutting wood, and Jim cut his arm off. Joe wrapped the arm in a plastic bag and took Jim to a surgeon.
The surgeon said "You're in luck! I'm an expert at reattaching limbs! Come back in 5 hours." So Joe left and when he returned in 5 hours the surgeon said "I got done quicker than I expected. Jim is down at the pub." Joe went to the pub and there was Jim, throwing darts.
A few weeks later, Joe and Jim were cutting wood again, and Jim cut his leg off. Joe put the leg in a plastic bag and took it and Jim back to the surgeon.
The surgeon said "No problem, but legs are a little tougher. Come back in 8 hours." Joe left and when he came back in 6 hours the surgeon said "I finished early, Jim's down at the soccer field." Joe went down to the soccer field and there was Jim, kicking goals.
A few weeks later, Jim had a terrible accident and cut his head off. Joe put the head in a plastic bag and took it and the rest of Jim to the surgeon.
The surgeon looked at the situation and said "Gosh, heads are really tough. Come back on 12 hours."
So Joe left and when he returned in twelve hours the surgeon said regretfully "I'm sorry, Jim died."
Joe said "I understand - heads are tough."
The surgeon said, "Oh no! The surgery went fine! Jim suffocated in that plastic bag."
Many articles taken from 'A word with the doctor', by Dr. John Windsor.