SummaryIn 14 cases of non-tuberculous empyemas treated by the fluid-emptying process and by intrapleural injections of penicillin the results are as follows :8 cases of recovery, improvement of 1 chronic case; 1 case of recovery after rib-resection and 4 deaths.All cases of acute pneumococcal empyemas were healed successfully ; there were several failures, however, in cases of empyemas caused by staphylococcus and anaerobiical bacilli.It is our opinion that acute pneumococcal empyemas should be treated by means of tapping and intrapleural injections of penicillin, and that surgical drainage should be considered only after a medical treatment extended over several weeks has failed.Conversely if cases of empyemas caused by other germs do not respond promptly to penicillin, drainage together with rib-resection must be applied as soon as possible.