CULTIVATION OF BACTERIA 67 



gallic acid. The small tube is quickly inserted and the whole sealed 

 by water or a rubber cork (Fig. 51). Solid culture media in test-tubes 

 can be inverted over the acid soda mixture, which is then covered 

 by a layer of albolene to prevent the absorption of oxygen from the 

 air. The displacement method is often used along with that of 

 absorption. 



ASSOCIATED WITH AEROBIC BACTERIA. Anaerobic bacteria mixed 

 with aerobic bacteria will grow in the apparent presence of oxygen, 

 the aerobic bacteria robbing the media of it. Thus, tetanus and 

 diphtheria grow together in an open flask of bouillon. 



METHOD FOR ADAPTING BACTERIA TO ANIMAL FLUIDS. The placing 

 of cultures in collodion sacs in the abdomens of animals has been used 

 extensively by the Pasteur school for exalting the virulence of bacteria 

 or trying to adapt them to species of animals differing from the one 

 from which they were isolated. 



The underlying idea is to grow the organisms in the peritoneal cavity 

 of an animal under such conditions that the waste products of the 

 germs will be removed, an abundant supply of nutrient material fur- 

 nished, and the germs themselves protected from the action of the 

 phagocytes. The hermetically sealed collodion sacs answer this pur- 

 pose. The collodion used is the U. S. Pharmacopoeia solution, which 

 by exposure to the air has been concentrated one-third. 



The sealed inoculated sacs are to be inserted into the peritoneal 

 cavity with every possible precaution for asepsis. The sacs are left 

 in place for days or months, as the experiment requires. 



