10 BACTERIA 



may be ingested substances but some are lipoidal or carbohy- 

 drate in nature. These bodies are demonstrated by staining 

 with basic dyes and may be of importance in determining the 

 mycobacteria. It is thought that they play a role in reproduc- 

 tion (Fig. 65). 



The food of the bacterium passes through the cell wall by 

 osmosis. The cell wall of certain organisms, for example the 



FIG. 6. Zooglea formation. (Leuconostoc.) (Kolle and Wassermann.) 



pneumococcus, undergoes a change whereby a mucilaginous or 

 gelatinous capsule is formed outside the cell wall. Its use is 

 not known. The cell wall is generally the first portion of the cell 

 to be attacked by certain specific substances (ferment) found 

 in the blood of immunized animals, called bacteriolysins and 

 agglutinins. Where great masses of bacteria are clumped in 

 excessive mucilaginous material we speak of this condition as 

 zooglea (Fig. 6). 



We sometimes find, as a prolongation of the cell wall, filament- 

 ous organs of locomotion known as flagella. Bacteria without 

 flagella are sometimes called gymnobacteria, those possessing 



