MINUTE STRUCTURE OF THE BACTERIAL CELL 59 



that of their entoplasm, the solvents within the cell diffuse 

 out through the semipermeable ectoplasm, and the remain- 

 ing protoplasm in the cell retracts and collects in irregular 

 particles in various portions of the cell. It is plausible that 

 this condensed protoplasm composes what are called meta- 

 chromatic and polar granules. Some authors have ascribed 

 to bacteria the power of spontaneous plasmolysis to explain 

 the irregular staining of such bacteria as Bacterium diphtherias, 

 Bacterium tuberculosis, and the polar staining of Bacillus 

 pestis (bubonic plague). It should not be overlooked 

 that when staining a preparation of bacteria all the prerequi- 

 sites for plasmolysis are present. For example, the heating 

 of the preparation before the stain is applied drives the water 

 out of the cell and concentrates the solutes, and consequently 

 causes a retraction of the cell protoplasm from the cell wall, 

 which may collect in granules. It is probable that the for- 

 mation of polar granules, together with the formation of 

 vacuoles, are either artificially produced, or that they are 

 degenerative changes in the bacterial cell. Definite granules 

 of sulphur have been noted in certain of the higher bacteria 

 (Beggiatoaceae). 



Nucleus. In regard to the perplexing question as to 

 whether or not a nucleus exists in the bacterial cell, there has 

 been a great deal of investigation. As stated before, there is 

 no definite and circumscribed nucleus in the bacterial cell. 

 When stained with the ordinary nuclear stains (hematoxylin, 

 basic anilin dyes, etc.), the material (chromatin) which takes 



