The management of effusion into the thorax will depend much upon the character and extent of the inflammatory process which produced it. Netter has shown that in children empyema is of tubercular origin in 25 per cent. of all cases. The other 75 per cent, is due principally to the pneumococcus, with the staphylococcus, streptococcus, the Eberth and colon bacillus as occasional sources of infection. In adults Netter and Eichhorst have found 65 to 69 per cent. to be tuberculous.
It is generally recognized that empyema resulting from tubercular pleurisy has a much less favorable prognosis than when of pneumococcus origin. The latter variety of cases is attended by a less stable proliferation and the lung is left more patent and resilient than is the case in tuberculosis.
A very small percentage of cases are permanently cured by aspiration. Da Costa believes the cures to be limited chiefly to post-pneumonia