294 METHODS OF IDENTIFICATION AND STUDY 



short arm 5 cm. and the long arm 20 cm., and connect 

 its short arm to the horizontal arm of the tube in the 

 culture flask by means of a length of pressure tubing, 

 provided with a screw clamp. 



3. Fill the culture flask completely with boiling 

 medium and pass the long piece of tubing through the 

 plug of an Erlenmeyer flask (150 c.c. capacity) which 

 contains 100 c.c. of the same medium. 



4. Sterilise these coupled flasks by the discontinuous 

 method, in the usual manner. 



Immediately the last sterilisation is completed, 

 screw up the clamp on the pressure tubing which con- 

 nects them, and allow them to cool. 



As the fluid cools and contracts it leaves a vacuum 

 in the neck of the flask below the rubber stopper. 



5. To inoculate the culture flask, withdraw the long 

 arm of the bent tube from the Erlenmeyer flask and 

 pass it to the bottom of a test-tube containing a young 

 cultivation (in a fluid medium similar to that contained 

 in the culture flask) of the organism it is desired to 

 investigate. 



6. Slightly release the clamp on the pressure tub- 

 ing to allow 4 or 5 c.c. of the culture to enter the 

 flask. 



7. Clamp the rubber tube tightly; remove the bent 

 glass tube from the culture tube and plunge it into a 

 flask containing recently boiled and quickly cooled dis- 

 tilled water. 



8. Release the clamp again arid wash in the remains 

 of the cultivation until the culture flask and tubing 

 are completely filled with water. 



9. Clamp the rubber tubing tightly and take away 

 the long-armed glass tubing. 



10. Prepare the gas receiver as in the previous 

 method (in this case, however, the mercury should be 

 warmed slightly) and fill the horizontal arm of the re- 

 ceiver with hot water. 



