Cytodiagnosis of Pleural Effusions

THERE are several varieties of pleural effusion where an examination of the cells in the fluid is as a rule unnecessary. These are the various forms of purulent effusion or empyema. Pus is pus all the world over, and its main scientific interest is not to be found in the cells which it contains, but in the organisms which cause its production and are to be found in it. It makes a great deal of difference to a patient's chances whether an empyema is due to the pneumococcus, streptococcus, staphylococcus, to the bursting of a tubercular cavity with a mixed infection of the pleura, to the bacillus typhosus, the bacillus coli and so on, but in almost all cases of empyema it is the organism which should be sought microscopically or by culture, while the exact look of the cells in the effusion is a matter of secondary importance. It is in serous effusions that the cells are of importance, and the history of this question is of considerable interest. Pleurisy is one of the most common of acute chest affections, and for many years it has been matter of discussion whether