CHAPTER VII 



BACTERIA 



It is necessary here to interpose a few remarks about a 

 large Individual class whose characters are somewhat peculiar 

 in that while the general habit is discontinuously multi- 

 cellular, at times it is filamentous, or, possibly, coenocytic. 

 This class comprises what are known as Bacteria. It is 

 to be noted, however, that the term is not used here in the 

 wide sense in which it is sometimes applied. 



Bacteria are sometimes divided into the Lower and 

 Higher Bacteria, the former including the free unicellular 

 microorganisms such as micrococci, bacilli, or spirilla, and the 

 latter, filamentous or coenocytic growths such as, for example, 

 the Bay Fungus. But as our present purpose deals with 

 types of living Continuity, and as truly coenocytic Individuals 

 form a type by themselves, we confine the term " bacterium " 

 solely to the unicellular microorganism. 



While a bacterium is essentially a unicellular organism, it 

 does not follow that the common belief is true, namely, 

 that it is a unicellular Individual ; or that when a bacterium 

 divides it reproduces itself. It is indeed quite possible that 

 the bacterial Individual is multicellular, and certain microbic 

 growth-phenomena distinctly suggest this. 



It is common knowledge that while certain types of bacteria 

 habitually multiply in discontinuity, each germ being free 

 and independent, others tend if undisturbed to form con- 

 tinuous bacterial series ; to develop, in fact, as bacterial 

 filaments (Pig. 14). 



Fig. 14. — Examples of bacterial filament, a, streptococcal 

 chain ; b, anthrav bacillus " filament." 

 GT 



