10 BACTERIOLOGY FOR NURSES 



upon the cell-body, sometimes occurring at one 

 end, sometimes at both ends, and in others entirely 

 surrounding the bacterium, as in the bacillus of 

 typhoid fever. 



, 



a b c 



FIG. 2. a. Spiral forms with flagellum at one end. 6. Spirals from 



water with flagella at both ends. c. Bacilli of typhoid fever with flagella 

 on all sides. 



The majority of bacteria having motility are 

 bacilli or spirilla. 



Mode of Multiplication. When bacteria have 

 reached their maximum size, cell-division occurs, 

 which divides the cells into two equal parts. Bacilli 

 and spirilla divide by transverse fission; while 

 among the cocci division may occur in one plane, 

 which results in chains (streptococci), or in two 

 planes, resulting in groups (staphylococci), or in 

 three planes, resulting in packets (sarcinse). 



Under favorable conditions fission occurs rapidly 

 (the hay bacillus in thirty minutes), from which 

 may be readily estimated the enormous multi- 

 plication which would result, should nothing occur 

 to check the reproduction. In a single twenty-four 

 hours the increase would reach hundreds of millions, 



