STUDIES ON HOST FACTORS IN PNEUMOCOCCUS INFECTIONS : II. THE PROTECTIVE ACTION OF TYPE I ANTIPNEUMOCOCCUS SERUM IN RABBITS.

The power of specific antipneumococcus serum to protect rabbits against infection with Type I Pneumococcus has been studied with reference to the capacity of the animal to utilize the specific antibodies. Under conditions ensuring relatively controlled genetic factors it was found that heavier animals and those with high white blood cell counts are much better able to utilize the passively conferred immune principles. The interrelationships of the extrinsic and intrinsic factors responsible for immunity have been discussed.