THE ANTIPROTEOLYTIC ACTIVITY OF SERUM : III. PHYSIOLOGICAL SIGNIFICANCE. THE INFLUENCE OF TRYPSIN AND OF ANTIPROTEASE ON BACTERIAL GROWTH AND SULFONAMIDE ACTION.

1. Heating diluted serum at 80 degrees C. for 10 minutes made it a better medium for bacterial growth. This is believed to have been at least partly due to destruction of the serum antiprotease. 2. Growth was accelerated, and proceeded further, in the presence of trypsin. 3. Growth was somewhat retarded in the presence of pancreatic trypsin inhibitor. 4. The bacteriostatic action of sulfathiazole in serum was reduced by heating the serum at 80 degrees C., and much more markedly (in any of the media studied) by adding trypsin. It was greater in serum and albumen than in peptone and meat infusion. 5. The significance of the experimental results was considered in relation to the possible influence of leucoprotease and of serum antiprotease on bacterial growth and sulfonamide action.