MINUTE STRUCTURE OF THE BACTERIAL CELL 53 



many animal cells. It may be stated that there is usually 

 a semblance of a cell wall in these cases. In a few instances 

 the cell wall of animal cells approximates the cell wall of the 

 plant in strength. The bacteria in structure stand between 

 the plant and the animal. For example, the cell wall is of 

 a higher order than the animal cell wall, but it is not so highly 

 developed as the cell wall of true plants. It has been positively 

 proved that the bacterial cell possess a limiting cell wall 

 similar to plant cells in some cases and animal cells in others. 

 Many other points go to show that the bacteria belong to an 

 intermediate class as far as structure is concerned. The cell 

 does not possess any clearly denned nucleus or nucleolus, and 

 in this particular differs from the majority of animal and 

 plant cells. Stained by the ordinary bacteriological stains 

 (anilin dyes), no definite structure can be demonstrated on 

 account of the intensity of the stain. Bacteria stain more 

 deeply with the anilin dyes than plant cells. 



Protoplasm. According to some authorities the protoplasm 

 of the bacterial cell is not distributed throughout the whole 

 cell, but composes a layer next to the cell wall. The central 

 part of the cell, in common with plant cells, contains the cell 

 sap, composed largely of water and organic and inorganic 

 substances in solution. The exact condition of affairs, in all 

 probability, is that there is a somewhat denser layer of proto- 

 plasm, called ectoplasm, next to the cell wall. This layer is 

 not definite and separate from the interior of the cell, thus 

 creating a central cavity as some authors state. Many 



