Bilateral spontaneous pneumothorax, occurring in the apparently healthy, is an extremely rare disease. Kjaergaard,1who reviewed the literature,2found only three such reported cases. McMahon,3who recently added another case to the group, found less than fifty bilateral cases reported from all causes. The case to be presented here is therefore of unusual interest, as the bilateral spontaneous pneumothorax not only occurred in an apparently healthy young man but probably became bilateral within a few hours after the onset. REPORT OF CASE E. N., a youth, aged 19, a tall, thin, athletic college student, walked into our office, July 7, 1933, in a condition on admission so critical that the following history had to be obtained from his mother, who accompanied him. One of his maternal aunts had diabetes, while a maternal uncle had asthma. A maternal uncle had died of diabetic coma; another maternal uncle had