1. The action of indophenoloxydase is generally diminished in the tissues (liver, renal cortex, heart muscle) of rabbits that die of pneumococcus septicemia. The diminution is more frequent and marked in the liver and kidney than in the heart muscle.
2. The diminished activity of indophenoloxydase becomes more evident when the tissues undergo autolysis. At 37° C. this ferment is much more easily destroyed in the tissues of the infected animals than in those from normal control animals (tables I, II, III, and IV). Exceptions are rare and they occur chiefly with the heart muscle.
3. Normal rabbit tissues, inoculated in vitro with pneumococcus culture, do not lose their indophenoloxydase much more quickly than do the normal controls, when they are kept either at room temperature or at 37° C. (tables IV, V, VI, and VII).
4. It is therefore probable that the diminished activity of the indophenoloxydase of tissues from rabbits with pneumococcus septicemia is not due to the presence of the pneumococcus in these tissues, but that it is associated with a pathological change in the animal cell during life.