1. Menkin's observations of the failure of inflammatory fixation in areas of acute inflammation due to Streptococcus haemolyticus have been confirmed.
2. The lack of inflammatory fixation in the presence of streptococci is not due to the passive nature of the streptococcus, but may be attributed to the production of (1) fibrinolytic, and (2) antifibrinogenic substances which dissolve the fibrin barrier, or prevent its formation, thus maintaining the patency of the lymphatics and capillaries and facilitating the dissemination of the organisms.
3. The production of fibrinolytic or antifibrinogenic substances, and the invasiveness of a given strain of streptococcus are correlative.
4. Both substances are relatively thermostable. Fibrinolysin is destroyed if held at 100°C. for 1 hour. The antifibrinogenic substance is weakened but is not destroyed under the same conditions.
5. There is evidence that both substances are antigenic, and exhibit some degree of type specificity.
6. The role of fibrinolysin and the antifibrinogenic factor in the invasion of the tissues by streptococci is discussed.