42 MORPHOLOGY AND CULTURE OF MICROORGANISMS. 



in the higher cells, since no nucleus in the ordinary sense has been 

 demonstrated in the bacterial cell. The work of Butschli. Swellen- 

 grebel, and Schaudinn, however, indicates the existence of karyo- 

 kinetic division in bacteria (Fig. 21). Division begins by an invagina- 

 tion of the protoplasm in the middle of the cell, which proceeds until 



<3/ 



FIG. 22. Bacillus butschlii. 1-6, Stages in the division of the vegetative cell; 

 7-9, rudimentary sexuality; 1-14, formation of spores; 15-16, germination of spores 

 (After Schaudinn from Guilliermond review, Bull. Inst. Past.} 



the cell protoplasm is completely separated. The cell wall then grows 

 in and finally splits forming the two ends of the new cells. These new 

 cell walls are formed at right angles with the long axis of the cell in 

 the case of the bacilli and spirilla, except in rarest instances. In the 

 case of micrococci, Jhejhrowing^of the cell wall across one diameter is 



