FILLING THE TUBES. 



99 



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

 into the tubes held under its opening. 



Fig. 19. 



Funnel for filling tubes with culture media. 



Jt is not necessary to sterilize the funnel, for the 

 medium is to be subjected to this process as soon as it 

 is in the test-tubes. 



Care should be taken that none of the medium is 

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

 cotton plugs become adherent to it and are not only 

 difficult to remove, but present a very untidy appear- 

 ance, and interfere, indeed, with the proper manipula- 

 tions. 



As soon as the tubes have been iilled they are to be 

 sterilized in the steam sterilizer for fifteen minutes on 



