74 LABORATORY BACTERIOLOGY 



EXERCISE XXV 



PYOGENIC BACTERIA (continued) 



110. Work for this exercise. Examine and carefully describe 

 the cultures made in Exercise XXIV. Note especially the 

 growth on the agar, gelatin, and potato, and in the tubes of 

 the bouillon containing the sugars. In describing the color 

 use color charts which are in the laboratory. 



Examine microscopically in (i) hanging-drop and (2) stained 

 cover-glass preparations the bacteria from the bouillon and 

 agar cultures. 



Measure a few of the bacteria in the stained preparations 

 from the agar cultures, and make a drawing of them, magnified 

 1000 diameters. 



Inoculate for Exercise XXVI a tube of each medium in 

 Groups A and B from a culture (furnished) of Ps. (Bacillus) 

 pyocyaneus. 



For suggestions in studying cultures and microscopic prep- 

 arations of bacteria, see Exercises VI and XII. 



Include in the notes the names of the different forms of 

 Micrococcus pyogenes and a classification of streptococci. 



