220 



PATHOGENIC BACTERIA. 



freshly boiled, still liquid, gelatin or agar-agar, as in 

 making the dilutions for plate-cultures, then drawn into 

 a long, slender sterile piece of glass tubing of small 

 calibre. When the tube is full the ends, which should 

 have been narrowed, are closed in a flame, and the cul- 



Fig. 39. — Novy's jars for anaerobic cultures. 



ture is hermetically sealed in an air-tight chamber. The 

 chief difficulty is in transplanting the growing colony. 

 To do this the tube must be opened with a file or a dia- 

 mond at the point where the colony desired is observed. 



