Abstract
In anesthetized dogs the popliteal lymph node alone, and the popliteal and iliac lymph nodes in series, have been perfused with solutions containing dog erythrocytes and streptococci. The perfusions have been carried out under conditions of lymph flow and pressure within the limits of those occurring in the actively moving dog, or after a severe degree of inflammatory swelling has developed. Figures for filtration are given, with protocols of typical experiments. They indicate that normal lymph nodes possess a high degree of filtering efficiency-an efficiency so great as to make it fairly certain that in a part kept at rest early in an infection, practically no microorganisms would escape the nodes in the line of drainage.