CULTIVATION OF ANAEROBIC BACTERIA. 



67 



It is necessary to transfer the bacteria to fresh gelatine about 

 every six weeks, lest the products of growth and decay given 

 off by the organisms destroy them. 



**<] 



CHAPTER XII. 



CULTIVATION OF ANAEROBIC BACTERIA. 



SPECIAL methods are ne*cessary for the culture of the anaerobic 

 variety of bacteria in order to procure a space devoid of oxygen. 



Liborius's High Cultures. The tube is filled about ^ QQ 

 | full with gelatine, which is then steamed in a water 

 bath and allowed to cool to 40 C., when it is inocu- 

 lated by means of a long platinum rod with small 

 loop, the movement being a rotary vertical one, and 

 the rod going to the bottom of the tube. 



The gelatine is next quickly solidified under ice ; 

 very little air is present. The anaerobic germs will 

 grow from the bottom upward, and any aerobins 

 present will develop first on top, this method being 

 one of isolation. 



From the anaerobic germs grown in the lower part, 

 a stab culture is made into another tube containing 



O 



f gelatine, the material being obtained by breaking 

 test-tube with the culture. 



Hesse's Method. A stab culture having been made 

 with anaerobic germs, gelatine in a semi-solid condi- 

 tion is poured into the tube until it is full, thus dis- 

 placing the air. (Fig. 39.) 



Esmarch's Method. Having inoculated a tube with L ^ b ^ u d s>s 

 the microbe, the gelatine is rolled out on the walls of 

 the tube, a " roll culture," and the rest of the interior filled with 

 gelatine, the tube being held in ice water. The colonies develop 

 upon the sides of the tube and can be examined microscopically. 



Gases like Hydrogen to replace the Oxygen, Several ar- 

 rangements for passing a stream of hydrogen through the 

 culture: 



