ae 
46 LABORATORY BACTERIOLOGY A 
ue 
EXERCISE XI | 
ra 
e 
INOCULATING SPECIAL MEDIA: AND EXAMINING 
CULTURES 
71. Work for this exercise. ,Inoculate, from a culture fur- 
nished of B. proteus mateaide tube of potato, one of milk, 
one of litmus milk, one of glucose agar, a fermentation tube 
and a test tube each of glucose, lactose, and saccharose bouillon. 
Label each and place in the incubator. 
Stain a preparation with alkaline methylene blue, another 
with carbol fuchsin, and a third with an aqueous solution of 
gentian violet from the bouillon and agar cultures (§ 47). 
Make a careful comparison of the preparations and note 
any difference in the appearance of the bacteria or in the 
intensity of the stain. Preserve as a permanent specimen, 
to accompany the notes, a preparation stained with each of 
the dyes. 
Prepare the aqueous solution of gentian violet (§ 38). 
72. The inoculation of glucose agar to determine the power 
of the organism to produce gas. Boil the tube of glucose agar 
in an open water bath until it is liquefied, then cool it down to 
a temperature of 40°C. and inoculate it with a loopful of the 
culture, carefully stir the agar with the loop, after which 
solidify it as quickly as possible. Label and stand in the 
incubator. 
73. The use of media containing the sugars. The sugars are 
employed as tests to determine whether or not the bacteria in 
question will ferment them, producing acids. Some bacteria 
will produce gas as well as acids. The latter is determined in 
the sugar-agar tubes. 
In the fermentation tubes we can determine both of these 
properties and also the quantity of gas set free. It is easier, 
1 Or any other gas-producing bacillus. 
7] 
! 
