Further Studies on the Mechanism of Transmissible Lysis of Bacteria.

Abstract

Observing carefully the progress of lysis under the microscope we noticed that disappearance of individual bacteria under the influence of phage is usually preceded by more or less marked swelling of the cells.1 A more detailed inquiry indicated that the swelling itself was due to imbibition of water which in turn appeared to be the result of intracellular digestion of bacterial cytoplasm,2 and consequent increase of osmotic pressure within the cells. The actual disappearance of cells from the field was therefore interpreted as due to bursting.3 We found further that if bacteria are grown on media in which free water was immobilized by the addition to the medium of hydrophilic colloids, the swelling was prevented and consequently lysis did not occur. On the contrary, in place of a marked fall in the number of bacteria (as would be the case if lysis had occurred), we observed actual increase in the number of bacteria when compared with control cultures grown on the same medium but in the absence of phage.4...