MORPHOLOGY AND RELATIONSHIPS OF MICROORGANISMS 33 



this ectoplast, the water from the cell in part passes out, the 

 protoplasm shrinks away from the cell wall, and the cell is said to 

 be plasmolyzed (noun, plasmolysis) . Such a plasmolyzed cell 

 shows clearly the ectoplast separated from the cell wall. When 

 a cell of certain species is placed in distilled water or a concentra- 



JB 



Fig. 11. Plasmolysis and plasmoptysis of bacterial cells: A, Plasmo- 

 lyzed bacterial cells; B, cells showing plasmoptysis, the protoplasm has burst 

 the cell wall and is escaping. (Adapted from Fischer.) 



tion of salt considerably less than that to which it has been accus- 

 tomed, the cell takes up water, the cell wall bursts, and part of the 

 protoplasm escapes. This phenomenon is called plasmoptysis. 

 The protoplasm of the cell is commonly homogeneous in appear- 

 ance, and stains best with the basic aniline dyes. Either a definite 



2) " F 



Fig. 12. Bacterial cell inclusions: A, Vacuoles in the cell, polar staining 

 rods; B, vacuolate spirilla; C, fat globules; D, glycogen granules; E, meta- 

 chromatic granules; F, sulphur granules. 



nucleus is not present, or the nuclear material is so scattered 

 as to make the entire mass functionally a nucleus. Some bac- 

 teria have been described as possessing a primitive type of 

 differentiated nucleus, but such structures cannot be discerned 

 in others. 



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