METHODS OF USING CULTURE MEDIA 



189 



and mixed with the alkaU when it is desired to do so. The 

 cover is now clamped in position with all joints well vase- 

 lined. Then the outlet tube is connected with a suction 

 pump and the air drawn out. jMeanwhile the inlet tube 

 has been connected with a hydrogen generator, and after 

 the jar is exhausted hydrogen is allowed to flow in, and this 

 process is repeated until one is satisfied that the air is 

 replaced. The suction exhausts the air from the tubes or 

 plates so that much less time is required to replace the 

 air with hydrogen. Finally the stop-cock is closed, and the 

 pyrogallol solution is gently shaken down and mixed with 

 the alkali so that any remaining oxygen will be absorbed. 



Fig. 124. — Novy jars. 



It must be remembered that facultative anaerobes as well 

 as anaerobes will grow under any of the above conditions, 

 so that cultures of organisms so obtained must be further 

 tested aerobically in order to determine to which group the 

 organisms belong. 



Reference has been made above to the "inoculation" of 

 culture media, which means introducing into the medium 

 used the desired material in the proper way. For small 

 quantities this is most conveniently done with platinum 

 "needles," that is, pieces of platinum wire inserted into the 

 ends of glass rods. The "straight" needle is a piece of 

 heavy platinum wire of about 0.022 inch in diameter (Fig. 

 125). It is used most frequently to inoculate all forms of 



