1. Rabbits living in an atmosphere of carbon monoxide react in general as guinea-pigs react.
2. The increased specific gravity of the blood in " carbon monoxide " rabbits is due wholly to the increase in the number of erythrocytes and of hemoglobin, and not to any change in the plasma.
3. Weigert's law of inertia, that production would continue after the stimulus has ceased to act, does not hold in the case of carbon monoxide stimulated rabbits.
4. Hemolysins, precipitins and agglutinins towards normal rabbit corpuscles and sera were not present in carbon monoxide rabbits.
5. " Hemopoeitin " or anything of a similar nature was not found in rabbits in any stage of erythrocyte degeneration or regeneration.