MORPHOLOGY AND CULTURE OF MICROORGANISMS 



that streptobacilli are formed. When arranged in pairs, the designa- 

 tion is diplobacilli. The length of the chains appears to depend not 

 only upon the cohesion of the bacilli but also upon the shape of the 





FIG. 67. Division forms of bacilli, a, Single; b, pairs; c, in threads. (After Novy.) 



end; those which have square ends frequently have very long chains, 

 while those with rounded ends have short chains or occur singly. 



A unique growth-form or cell aggregate is that due to the post fission 

 movement of the cell as described by Hill in cultures of Bact. diph- 



f/ 



III I /"/ 



!'iii 4* 



tiff 



iii ' "I/ >' 



?/ ; ,"// // 



II 



Ili/L 



"'ii tiiii/i/ 



'//// /;////// 



FIG. 68. Threads of Bact. anthracis. (After Migula.) 



theriae. On fission the two daughter cells are not completely separated 

 but remain attached at one place. This leads to a movement similar 

 to the closing of a jack knife. In this way the two sister cells are 

 brought to rest at an obtuse, a right or an acute angle to each other. 

 They may be even brought parallel. 



