THE STUDY OF OBLIGATELY ANAEROBIC BACTERIA in „-l 1 



hydrogen; (3) tube of soda lime; (-1) plasticene (see footnote 3); 

 (5) water vacuum pump for evacuation. 



Method: Place plates in Brewer jar. Add tube of methylene 

 blue solution (see p. iii.i3-5). Include a tube of soda lime in the jar 

 to absorb excess CO2. Place roll of (warmed) plasticene around 

 rim of jar. Put on lid and press down on plasticene to form seal. 

 Add the lid clamp but tighten only slightly. If used with illuminat- 

 ing gas, attach the jar by the rubber tubing to the water vacuum 

 pump. Evacuate until the manometer or gauge reads approximately 

 20 cm. or 8 inches. After this degree of evacuation is reached, con- 

 nect the rubber tube to the gas supply (a three way stop-cock facili- 

 tates this change without loss of vacuum). Attach the electric 

 plug (110 volt AC or DC) and allow the gas and electric current to 

 remain attached for 30 to 45 minutes. At the end of this time clamp 

 the rubber tube tightly, remove the electric cord, and place the jar in 

 the incubator. (Formation of water droplets on the inside walls of 

 the jar indicates the proper functioning of the apparatus.) To open 

 the jar, remove the clamp and insert a knife blade between the lid 

 and rim of the jar. // used with hydrogen, attach the jar, without 

 evacuation, to the hydrogen tank and admit the gas at a pressure of 

 1-2 lb. per square inch. Attach the electric connection and allow 

 the current and gas both to remain on for 30 minutes. Then treat 

 the jar as above. 



Advantages: Convenient system for incubation of a number of plates in experi- 

 ments where speed of obtaining anaerobiosis is essential. Recommended for clinical 

 laboratories. Inexpensive system after the initial outlay for apparatus. Danger 

 of explosions is less in the Brewer jar than in the Mclntosh-Fildes jar. Disadvantages: 

 Some possibility of explosion or cracking of jar. Initial expense of equipment is 

 more than for other methods discussed above — but this may be a good investment 

 if routine work is to be done over a period of time. Requires source of hydrogen or 

 illuminating gas and electricity; while these are available in most laboratories, they 

 are not available in others such as some mobile laboratory units, temporary labora- 

 tories in field surveys, etc. 



Mcintosh and fildes jar" 



Materials: (1) Mcintosh and Fildes jar; (2) protective box or 

 cage of galvanized wire; (3) cylinder of hydrogen {■preferable) or 

 hydrogen generator; (4) reducing valve for hydrogen cylinder; 

 (5) resistance coil (approximately 175 ohms for 110 volts or 350 ohms 

 for 220 volts); (6) electrical wire for connections; (7) three-foot 

 length of rubber tubing. 



Method: (Adapted from various sources, including directions 

 issued with jar purchased from Arthur H. Thomas Company) : 

 Clean surfaces of jar and lid with xylol. Apply suitable sealing 

 medium or hard tallow to these. Grease tips and threads of needle 

 valves. Place cultures in jar and add tube of methylene blue 

 indicator solution (see p. 11143-5). Place lid on jar and tighten the 



^^Mclntosh and Fildes jar. Arthur H. Thomas Company, Philadelphia, Pennsyl- 

 vania. Model No. 1085 (glass) or 1085-B (aluminum). A convenient cage is Model 

 No. 1085-F. 



