I04 



BACTERIA, YEASTS, AND MOLDS 



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the presence or absence of these motor hairs. They 



are known by the name of flagella. 



Spherical Bacteria: Cocci. 

 The simplest type of bac- 

 teria consists of those that 

 are in the shape of a minute 

 sphere. Their size differs 

 somewhat, but they are 

 always extremely minute, and 

 about all that can be said in 

 regard to them is that they 

 are spherical organisms, 

 sometimes possessing flagella 

 and sometimes apparently 



FIG. 48. Cocci, bacilli, and bac- without them. No internal 

 teria. a (Coccus), b and c {Bacii- Structure is known. They 



/«j), show flagella; d (Bacterium) multiply SOmctimCS in SUCh 

 has no flagella. 



a way as 

 to produce long chains (Fig. 49, a), 

 sometimes so as to produce groups of 

 fours or groups of eight or sixteen 

 (Fig. 49, b, c, d). The general name 

 given to spherical bacteria is coccus, and 

 to this name are sometimes prefixed ^'.^•49- Cocci show- 



ing methods of mul- 



certain other syllables to indicate certam tipiication. a, strep- 



characters. Streptococcus is a name tococcus; b. Micro- 



given to cocci forming chains (Fig. 49, <-<"-'^«j; ^ and d, 

 a), and Micrococcus to those forming 

 fours or irregular masses as at b. The term Sarcina is 

 the name given to those that form solid masses such as 

 shown in Fig. 49, c and d. 



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