PYOGENIC BACTERIA 71 
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EXERCISE XXII 
PYOGENIC BACTERIA (continued) 
106. Pseudomonas pyocyaneus, commonly known as the 
bacillus of green pus, blue pus, or blue-green pus, is quite 
widely distributed in nature. While ordinarily it has been 
considered of little pathogenic importance, it is known to pos- 
sess at times, and under certain conditions, marked infecting 
powers. This organism has been called the honey bacillus, 
on account of the peculiar odor emitted from its cultures. It 
is to be differentiated from Ps. fluorescens liquefaciens and its 
varieties, which frequently appear in water. 
107. Work for this exercise. Examine and carefully describe 
the cultures made in Exercise XXI. 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 (1) 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 XXIII a tube of each medium in 
groups A and B from a culture (furnished) of Bact. Anthracis. 
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. 
