60 ESSENTIALS OP BACTERIOLOGY. 



It is necessary to transfer the bacteria to fresh gelatine about 

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

 oft* by the organisms destroy them. 



CHAPTER XII. 



CULTIVATION OF ANAEROBIC BACTERIA. 



SPECIAL- methods are necessary for the culture of the anaerobic 

 variety of bacteria in order to procure a space devoid of 0x3* gen. 

 FIG 33 Several measures have been adopted of which the 

 easiest and most serviceable are the following : 



Liborius's High Cultures. The tube is filled about 

 f 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 ana?robic germs will 

 grow 7 from the bottom upward, and any rcrobins 

 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 

 gelatine, the material being obtained by breaking 

 test-tube with the culture. 



Hesse's Method. A stab culture having been made 

 with ana?robic germs, gelatine in a semi-solid condi- 

 Liborius's t j on {s p (nire( i j n t o the tube until it is full, thus dis- 



IIU'tlllMl. - . - . T ,. _ . . 



placing the air. (r ig. .54. ) 



Esmarch's Method. Having inoculated a tube with the 

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

 "roll culture," and the rest of the interior filled up with gela- 

 tine, the tube being held in ice water in the meanwhile. The 

 colonies develop upon the sides of the tube and can be easily 

 examined microscopically. 



