BACILLUS COLI AND BACILLUS SUIPESTIFER 85 
EXERCISE XXXII 
BACILLUS COLI AND BACILLUS SUIPESTIFER 
129. Work for this exercise. Reéxamine the cultures of 
B. coi and note any changes which have occurred in their 
appearance. Determine the gas formula in the fermentation 
tubes of the different sugars. Place the milk and litmus-milk 
cultures in the incubator and reéxamine them later. 
Examine carefully and describe the cultures of B. suzpestifer. 
Examine microscopically at least one culture. Note especially 
its motility. : 
Examine and describe fully the colonies on ‘the gelatin plates. 
Preserve the plates and examine them in the following exercises. 
Examine microscopically, in a’stained preparation, the bac- 
teria from a colony on the gelatin plate. Preserve a prepara- 
{tion to accompany the notes. a ee 
Isolate &. coli from the intestine of an animal. The intestine 
will be furnished. , “ 
Inoculate for Exercise XXXIII a tube of each medium in 
groups A and D with &. Aphosus, and in group D With B. para- 
colon, from cultures furnished. 
130. Isolating B. coli from the intestine. Carefully open 
the intestine by a longitudinal incision. Scrape away the con- 
tents, if any, from a small area of the mucous membrane. Take 
a loopful of the mucus from the surface of the mucous mem- 
brane and inoculate a large tube of liquefied gelatin with it. 
After shaking the tube carefully, inoculate a second tube with 
2 loopfuls from the first, and a third with 3 loopfuls from the 
second. Pour the gelatin into Petri dishes and label them. 
These plates should be examined daily. The colonies of B. cot 
can be distinguished from others which may appear by their 
thin spreading growth, sharply defined but irregular borders, 
and their bluish appearance, especially with transmitted light. 
