BETSY Harris, MD, Assistant Resident in Medicine, the Jewish Hospital of St Louis: A 49-year-old woman was admitted to the hospital with a five-day history of short-ness of breath. Two weeks before admission, a cough that produced "some whitish material" developed and an oral temperature of 37°C was recorded. At that time, the lungs were clear to auscultation and percussion. Tetracycline hydrochloride therapy (250 mg four times a day) resulted in moderate symptomatic relief within two days. Subsequently, the patient noted the progressive development of shortness of breath when she was at rest (which was exacerbated by exertion), diaphoresis, and a productive cough. She had smoked one pack of cigarettes per day for 20 years. She denied exposure to potentially toxic sprays or to persons with respiratory diseases. She had no allergies. Clinically, she appeared to be a well-nourished, afebrile woman in moderate respiratory distress. Physical examination results were essentially