FURTHER OBSERVATIONS ON THE USE OF PNEUMOCOCCUS EXTRACTS IN EFFECTING TRANSFORMATION OF TYPE IN VITRO

Abstract

Pneumococcus extracts highly active in inducing the in vitro transformation of the specific types of Pneumococcus have been prepared by dissolving S cells with sodium desoxycholate, precipitating the dissolved material in alcohol in which the bile salt remains soluble, and extracting the precipitate in salt solution. Further purification of these active extracts has been attained by the removal of considerable inactive material by charcoal adsorption and by reprecipitation of the adsorbed extract in alcohol or acetone. The importance of using young cultures for extraction, and of preventing autolysis during the preparation of the extracts, is emphasized.