THE CELL WALL AND THE OYTOPLASMIG MEMBRANE 



27 



The Cell Wall and the Cytoplasmic Membrane. — There seems to be general 

 agreement that bacterial cells may be differentiated with varying degrees of dis- 

 tinctness, into two zones, which have been variously called cell-membrane and 

 protoplasm, ectoplasm and endoplasm, and even cortex and medulla. Until a 



ii 



Fig. 10. — Electron Micrographs of Bacteria. 



A. Sir. pyogenes, showing the continuity of the cell wall along the length of the 



chain (x 39,000). (Miuld and Lackman, 1941.) 



B. B. cereus, at the junction of two cells, joined by an inner thread of cytoplasm and 



an outer, continuous cell wall ( x 34,000). (Johnson, 1944.) 



(From micrographs kindly supplied by Dr. Stuart Mudd and Dr. F. H. Johnson.) 



