Careful studies of the flora of the tonsils and of the nasopharyngeal cavities have been made. The discovery of hemolytic streptococci is stressed as the most important bacteriologic finding. They are reported as present in approximately 50 per cent. of throats with extreme variations of from 10 to 100 per cent. In the nasopharynx they have been found less frequently and in smaller numbers. The importance of virulent hemolytic streptococci being the causative agent of many clinical conditions is well established. The rôle of these organisms as secondary invaders in postinfluenzal pneumonia, empyema, etc., is recognized. Also the ability of these bacteria to produce lesions in the stomach, gallbladder, appendix and endocardium; these lesions being secondary to primary foci of infection in the tonsils, teeth, etc., is stoutly affirmed by many. Therefore, the rôle played by streptococci in disease processes is an important one.
The steady progress that has been