A man went to see his doctor because he was suffering from a miserable cold. His doctor prescribed some pills, but they didn’t help.
On his next visit the doctor gave him an injection, but that didn’t do any good.
On his third visit the doctor told the man, “Go home and take a hot bath. As soon as you finish bathing, throw open all the windows and stand in the draft.”
“But doc,” protested the patient, “if I do that, I’ll get pneumonia.”
“I know,” said the doctor, “I can cure pneumonia.”