Crispin Fisher’s enjoyable letter1 brought to mind an experience I had as a teaching GP on a cold morning’s surgery. First of all I saw a male in his 50s with flu-like symptoms and high temperature. Auscultation of his chest disclosed bilateral crepitations in most areas. I let my trainee and student listen to his chest. I decided he needed to go to hospital. While waiting for the admissions officer at the local hospital, the three of us discussed possible diagnoses and management. The patient was duly admitted. I was very satisfied, especially having been observed by a trainee and medical student. Later that morning I saw a patient in his 30s with a cough. To my surprise he also had crepitations on the base of one side only. He was a smoker. I sent him for a chest X-ray at the local chest clinic. Later that day, I phoned the hospital to check on my patient. The registrar told me the patient had only a minor chest infection. The X-ray was clear and he had been sent home with antibiotics. I then phoned the chest clinic and found that the second patient’s X-ray was also clear. I was very surprised. Fortunately, neither the trainee nor medical student was with me, so I escaped embarrassment. I wondered what might have gone wrong. A careful examination of my stethoscope revealed a hairline crack on the plastic tube on the right side, just below the attachment with the metal. This crack became wider when I moved the stethoscope from side to side, but did not open much in the upright hanging position. I never used it again. It is still with me as a piece in my personal museum. I revealed the truth to my trainee and the medical student the following day and they both saw the funny side. We are, after all, only human.