1. Intramuscular dosage of antipneumococcus sera in a standard dermal pneumococcic infection in rabbits is as effective as intravenous dosage provided the degree of blood stream invasion be not unusually high.
2. The immediate bactericidal effect of doses of serum given intramuscularly is equal to that of the same doses given intravenously in the cases of mild and moderately severe bacteremias.
3. The intramuscular method of serum administration in human beings with lobar pneumonia deserves a carefully controlled clinical trial.