THE SPIROCHETICIDAL ACTION OF PENICILLIN IN VITRO AND ITS TEMPERATURE COEFFICIENT

Abstract
1. Penicillin was found to be actively spirocheticidal in vitro against the Reiter, Kazan, Nichols, and Noguchi strains of so called S. pallida, and a strain of mouth spirochetes. The threshold concentration was 0.01 unit per Cc. (1–160,000,000 penicillin). The rate and degree of action increased with the concentration of penicillin up to a level of approximately 0.1 to 0.25 unit per cc., which rendered more than 99 per cent of the organisms non-viable within 12 hours. Higher concentrations did not appreciably accelerate the effect.