The site of specific substances in capsulated organisms

Abstract

Applying a method of selective separation of the specific high polymers the intracellular site of the specific substance in the Copenhagen strain of Pneumococcus Type II was demonstrated, by electron microscopy; the specific polymeric material assumed to form the capsule is situated within the bacterial cell and the electron density of this material is sufficiently high to permit its detection.The possibility of obtaining electron micrographs of the polymeric substances as contained in the cells or after their diffusion into the medium or when secreted as slime, suggests that the current concept of the capsules as the site of the specific substances may have to be reviewed.The electron micrographs were made by Dr A. Petrovici to whom I express my thanks.