12 THE GENERAL CHARACTERS OF MICROORGANISMS. 



Classification. Based upon the distinctions thus mentioned, 

 the bacteria are divided into groups: 



SPHERICAL BACTERIA: 



Dividing in one plain, so as to form chains (Fig. 9, a), Strepto- 

 coccus. 



Dividing in two plains, and not forming chains (Fig. 9, b), 

 Micrococcus. 



Dividing in three plains, and forming 

 cubical masses (Fig. 9, c), Sarcina. 



ROD-SHAPED BACTERIA: 



With flagella and consequently 

 motile (Fig. 8)*, Bacillus. 

 Without flagella and consequently 

 FIG Q.-Showing different non-motile (Fig. 7, b), Bacterium. 



types of cocci, a, b, and c, Micro- 

 cocci; d, Streptococci; e, Sar- With a single flagellum, Pseudo- 



monas. 

 SPIRAL BACTERIA (Fig. 3, a), Spirillum. 



The genus BACILLUS is further divided as follows: 



Bacilli with only one flagellum (Fig. 8, c) are named Mono- 



trichic Bacilli, or Pseudomonas. 



Bacilli with one flagellum at each end, Microsporon. 



Bacilli with a tuft of .flagella at one end (Fig. 8, b), are called 



Lophotrichic Bacilli. 



Bacilli with flagella over the whole body (Fig. 8, a) are called 



Peritrichic Bacilli. 



HIGHER BACTERIA (Cladothrix,Leptothrix,Streptothrix, Actinomyces) 



(Fig. 10). 



Under this head are included a few forms of fungi which re- 

 semble other bacteria in some respects, but differ in others. They 

 are composed of threads which are commonly larger than the 



* Unfortunately bacteriologists are not agreed to-day in regard to the 

 use of the terms above given. The names Bacillus and Bacterium are not 

 always used as here stated, and recent classification of the spherical forms 

 recognizes, in addition to the names given, three others, Diplococcus, Meta- 

 coccus, and Ascococcus. This variation in nomenclature results in great 

 confusion. In the absence of any well-accepted classification to-day, we 

 shall in this book use the names 'as above defined. 



