VARIATIONS IN THE PNEUMOCOCCUS INDUCED BY GROWTH IN IMMUNE SERUM.

1. The growth of virulent pneumococci in homologous immune serum produces (a) variations in agglutinability, (b) decrease in virulence, (c) inhibition of capsule formation, (d) increase in phagocytability with normal serum, and (e) change in absorption power and antigenic properties. 2. Reversion to the original type in these changed forms takes place upon animal passage.