SYSTEMATIC STUDY OF SPECIES OF BACTERIA. lOI 



CHAPTER VIII. 

 SYSTEMATIC STUDY OF SPECIES OF BACTERIA. 



In order to conduct the study of any species of bacteria it is 

 necessary to have the organism isolated in a pure culture. This 

 is best accompHshed by the plate method already described. 

 Having thus obtained the organism in pure culture, it is to be 

 examined with reference to its behavior in certain particulars. 

 It is well for the beginner to study a few known species of sapro- 

 phytes obtained from some reliable laboratory in pure culture. 

 The points which are to be considered can be illustrated best by 

 presenting them in tabular form, filling out the items of the 

 table for a given species of bacteria. 



1. Name. 



2. Habitat or source. 



3. Morphology; grouping, as in chains or in zooglceae. 



4. Size. 



5. Staining properties. Behavior by Gram's method. 



6. Capsule, present or otherwise. 



7. Spore formation. 



8. Motility, flagella. 



Growth on culture-media. 



9. Relation of growth to temperature. 



10. Gelatin; observe whether the gelatin is hquefied or not. 



Colonies in gelatin plates, study under low power of 

 microscope. 



11. Agar. Colonies in agar plates, study under low power of 



microscope. 



12. Bouillon; note cloudiness, pellicle, or precipitate. 



13. Milk; observe whether or not the milk is coagulated 



and subsequently peptonized. 



