The frequency of incidents resulting from Abrams needle biopsy is very low provided certain contraindications are respected : pneumothorax, 3.1% of cases ; hemorrhages, 1.3% ; neoplastic contamination of the bioptic tract, 1.9%. Serious accidents are rare. We only observed 2 serious hemorrhages, one in 1964, the other in 1968. In the latter case, the pleural hemorrhage caused a very serious respiratory insufficiency. The delayed functional reaction is still not well known. However the occurrence of immediate accidents could reflect on radiological sequelae. The value of this examination seems today to decrease slightly at the same time as the frequency of pulmonary tuberculosis decreases. Indeed pulmonary tuberculosis is the main indication for this method because of the history and because of the possibility of culture on Loewenstein medium. In cancer, needle biopsy has two drawbacks, that of being blind and yielding only small samples, while pleuroscopy is free of them. In a series of 77 examinations including 45 cancers, the positivity reached 80%. In only 2 cases did pleuroscopy give a falsely positive result. In the remaining cases there was no neoplastic invasion of the pleura.