62 



ESSENTIALS OF BACTERIOLOGY 



The inoculation occurs through a very fine opening made in 

 the shell with a hot platinum needle; after inoculation, the open- 

 ing is covered with a piece of sterilized 

 paper, and collodion. 



Boiled Eggs. Eggs boiled, shell re- 

 moved over small portion, and the co- 

 agulated albumen stroked with the 

 material. 



Guinea-pig Bouillon. The flesh of 

 guinea-pigs, as well as that of other 

 experiment animals, is used instead of 

 beef in the preparation of bouillon, for 

 the growth of special germs. 



The extracts of different organs have 

 been added to the various media for 

 experimentation. 



Fermentation Tube. For showing 

 the presence of gas or fermentation the 

 Smith tube (Fig. 28) or some of its 

 modifications must be used. The closed 

 end and part of the bulb are filled with 

 the glucose or dextrose bouillon and 



sterilized at low temperatures for three successive days, then 

 inoculated, and placed in the incubator. Gas forms gradu- 

 ally, displacing the fluid in the closed end. 



Fig. 28. Smith's fer- 

 mentation tube. 



CHAPTER X 

 INOCULATION OF GELATIN AND AGAR 



Glass Slide Cultures. Formerly the gelatin was poured on 

 little glass slides, such as are used for microscopic purposes, 

 and after it had become hard, inoculated in separate spots as 

 with potatoes. 



