LABORATORY Y/ORK IN BACTERIOLOGY. 



i. 



FORM AND CLASSIFICATION. 



Bacteria as single-celled microscopic plants. 



.Relation to algae to fungi to yeasts. 

 Classified according to external form into 

 Micrococcus spherical. 

 Bacillus rod-shaped. 

 Spirillum screw-shaped. 



The term bacterium still used occasionally to desig- 

 nate a very short bacillus. 



Vibrio is the term applied to organisms which 

 may form spirals, but commonly grow in seg- 

 ments of a spiral giving rise to comma or 

 ^ N shaped forms. 



Lack of a natural classification of bacteria. 

 Variation in form as a result of natural conditions 

 environment. 



Young and fully developed cells. 



Nature of the medium on whhh the growth occurs. 



Solid and liquid media. 



Temperature. 



Unfavorable media give rise to involution forms 



degenerations. 



Variations resulting from artificial conditions 

 methods of examination. 



Deposition of aniline dyes. Simple and double 

 stains, as of tubercle and of leprosy bacillus. 

 Contraction of protoplasm by alcohol by iodine. 

 Action of heat. 



Constancy of form and of species. 

 Demonstration of, Micrococcup, 

 Bacillus, 

 Spirillum. 



