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 a shot, 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."