28 THE CYTOLOGY AND LIFE-HISTORY OF BACTERIA 



These two methods of cell-division are correlated with the " smooth " 

 and the " rough " filamentous morphological types of bacteria respectively. 

 Parallel types occur in coccal genera, most of which contain two, four or 

 more cells in each coccus. Four cells is normal number in many cocci, 

 commonly regarded as unicellular. 



(9 



(KtproJiicctl from llw Journal ,,/ (,c,u>„l Mi. 



A 



Fig. !» 

 BEHAVIOUR OF THE CELL WALL IN DIVIDING STREPTOCOCCI 



A. Long-chained streptoccus. Division is by the production of cross-walls, each 

 parallel to the last, exactly as in rough bacilli. 



B. Short-chained streptococcus. Division is by constriction of the cell wall. 

 All stained by tannic-acid-violet • 3000. 



A multicellular structure, sometimes with as many as twenty cells, separated 

 by cross-walls and cytoplasmic septa, in each bacterium, has been demonstrated 

 in nearly all Gram-positive bacteria. An extreme multicellularity is found in 

 the giant bacteria such as Caryophanon and Oscillospira. 



That the multicellularity of these bacteria is fundamental, and by no 

 means a superficial subdivision of filaments by the irregular growth of septa, 

 is shown by the observation of Tomcsik (195 1), that in Bacillus anthracis the 

 characteristic division of the bacillus into four small cells extends also to the 

 polypeptide capsule, in which lines of demarcation can be seen, corresponding 

 to the positions o^ the cross-walls internally. 



