140 



BACTERIOLOGY. 



use of a separating funnel, such as is shown in Fig. 

 23. The liquefied medium is poured into this funnel, 

 which has been carefully washed, and by pressing the 

 pinchcock with which the funnel is provided the desired 

 amount of material (5-10 c.c.) may be allowed to flow 

 into the tubes held under its opening. It is not neces- 

 sary to sterilize the funnel, for the medium is to be sub- 

 jected to this process as soon as it is in the test-tubes. 



FIG. 28. 



Funnel for filling tubes with culture-media. 



Care should be taken that none of the medium is 

 dropped upon the mouth of the test-tube, otherwise the 

 cotton plug becomes adherent to it, and is not^ only 

 difficult to remove, but presents a very untidy appear- 

 ance and interferes materially with the manipulations. 



