THE ACTION OF PNEUMOCOCCUS ON BLOOD.

The reduction of the oxygen capacity which occurs after incubating pneumococcus cultures with washed rabbit corpuscles is due to the formation of methemoglobin (or some derivative of hemoglobin with identical optical constants for three regions in the spectrum). The substance which induces the change is also present in the sterile filtrate of autolyzed cultures. By analogy we feel justified in concluding that the mechanism of the reduction of the oxygen capacity in human lobar pneumonia is at least in part of the same nature. To determine the frequency and intensity of the phenomenon in lobar pneumonia, and thereby to establish its clinical significance, is the next step and a problem upon which we are now engaged.