THE PROTECTIVE ACTION OF TYPE I ANTIPNEUMOCOCCUS SERUM IN MICE : II. THE COURSE OF THE INFECTIOUS PROCESS.

Observations are reported which concern the nature of the infectious process resulting from the intraperitoneal injection of mice with virulent pneumococci. The course of the infection has been figuratively reconstructed on the basis of the following data: The rate of bacterial multiplication, the numbers of cells present in the peritoneal cavity, the character of these cells at various stages, and the rate of phagocytosis. The significant alterations in this infectious process brought about by the administration of type specific immune serum are described, and the general significance of the findings discussed with reference to the functions of the immune serum and the rôle of phagocytes in protection.