1. Studies on Treponema Pallidum and Syphilis. Hans Zinsser, J. G. Hopkins, and Malcolm McBurney:
Treponemacidal Action of Immune Rabbit Serum on Culture Pallida. The experiments reported showed the normal rabbit serum was treponemacidal when as much as 1 cc. was used but seldom in smaller amounts, whereas the serum of animals immunized against cultures of treponemata showed the effect in amounts as small as 0.01 cc. This property of the immune serum was destroyed by heating to 56°C. for half an hour, and such inactivated serum could be reactivated by the addition of 0.05 cc. of normal serum.
Group Agglutinations of Culture Treponemata in Pallidum Antiserum. Serum obtained by immunizing rabbits against cultures of treponema pallidum agglutinated strains of this organism in amounts from 0.001 to 0.00025 cc. It showed an equally powerful action against the treponema calligyrum and a weaker action against T. refringens, T. microdentium and against a small treponema isolated from the tonsil.