TUBING OF MEDIA. 



511 



drawn up into a sterile bulb pipette (Pig. 61), and then 

 transferred direct to these tubes. The addition of sterile 

 litmus solution to sterile media is preferable to the ordinary 

 method of adding the litmus to the medium before steril- 

 ization. 



Tubing of Media. 



In many experiments, as in the disinfection tests pres 

 ently to be described, it is desirable to 

 employ measured .amounts of bouillon. 

 This can be done expeditiously by means 

 of the simple apparatus shown in Pig. 

 72. The lower end of a 100 c.c. burette 

 is attached to a small glass T-tube which 

 connects with the reservoir flask. The 

 burette can thus be readily filled and 

 exact amounts can be measured out into 

 the tubes. 



For rapid tubing of gelatin, bouillon, 

 agar, etc., where it is not essential to 

 employ a definite volume it is well to 

 employ a funnel or glass globe which is 

 connected by means of rubber tubing with 

 a drawn-out glass tube. A Mohr's clamp 

 is attached to the rubber tubing or in its 

 stead a glass stop -cock may be used. 

 The perforation in the latter should have 

 a diameter of about 3 mm. Such an ap- 

 paratus is obtained by disconnecting the . f}'^- ?? 

 long rubber tube at a in Pig. 72. 

 simple apparatus can, therefore, be em- ^^' ^' ^'^ 

 ployed for ordinary tubing of media, or for measuring out 

 definite volumes. 



Apparatus for 

 tubing definite quantities 

 Thi'5 °' media. For ordinary 

 *° tubing disconnect at a 



