280 



L. D. BXJSHNELL 



tainecl for leaks. As the phosphorus burns there is considerable 

 positive pressure due to the increase in temperature The pet 

 cock should always be left open until this is nearly neutralized, 

 otherwise leaks may develop. If there are leaks around (he hd, 

 they can be detected by the puffing out of phosphorus fumes. 

 The burning usually ceases in a very few seconds, due to the 

 exhaustion of oxygen; and the jar is filled with fumes. In glass 

 jars these are seen to subside in about fifteen minutes if there is 

 plenty of fresh water in the bottom. Anaerobic conditions are 



Fig. 1. Anaerobic Jar with 

 Lid in Place 



Fig. 2. Anaerobic Jar with Lid Remo\'ed 



thus obtained about the cultures almost instantly. The rate at 

 which oxygen dissolved in the medium, will diffuse out will 

 depend upon the medium. Litmus milk and broth containing 

 methylene blue are decolorized within a few hours. Deep agar 

 tubes containing methylene blue are not decolorized to the bot- 

 tom for about three days. Apparently oxygen diffuses out 

 about as slowly as it diffuses into the media, since oxygen will 

 diffuse into agar at the rate of about 1 cm. per dienl. This is 

 indicated by the fact that most vigorously growing anaerobes 

 will grow to within one or 1.5 cm. of the surface of a deep agar 

 tube. 



The jar which we have described is of light weight, quickly 

 sealed and very convenient. It may also be used with hj-drogon 

 or illuminating gas. If alkaline pyrogallate is used it must be 



