Is 





Fig. 7. Thin sections of Escherichia coli infected with bacteriophage. 

 (a) Coccoid and lysed cells showing multilayered wall and underlying 

 membrane (x 32,500). By courtesy of Drs. Kellenberger and Ryter 

 (Ref. 39). {b) Cell showing complete differentiation of wall, qtoplas- 

 mic membrane, and residual cytoplasm upon phage infection 

 (X 34,000). By courtesy of Drs. Kellenberger and Boy de la Tour, 

 unpublished electron micrograph. 



13 



