MORPHOLOGY OF BACTKKIA 



27 



l)ut they arc more complex in structure, possessing a def- 

 inite nucleus \\hieh is small, and recognizable with difficult y, 

 if at all, in unstained preparations. It can, however, he 

 demonstrated by proper methods of staining. The proto- 

 plasm contains granules, oil globules, and vacuoles that are 



Ki.u. 14. Yeasts 



The cells reproduce by budding. The large clear areas in some of the cells 

 are vacuoles, which are filled with cell sap 



tilled with cell sap. The wall of the yeast cell is a rela- 

 tively firm structure of yeast cellulose. 



The yeast cell may be oval, ellipsoidal, or cylindrical, 

 rarely spherical. The shape is not so constant in form for 

 a given species as is the case with the bacteria. The yeasts 

 are, as a rule, larger than the bacteria, the cells commonly 

 ranging from 2.5 to 12 microns in width. The grouping 

 shows little of the regularity that is noted among some of 

 the bacteria. Reproduction is accomplished by the vegeta- 

 tive method, or by the production of spores. The former 

 takes place by the formation of buds on any portion of the 



