278 L. D. BUSHNELL 



This method makes use of metallic phosphorus for the removal 

 of oxygen. Most authors mention this method of obtaining 

 anaerobic conditions in their review of the literature, but so far 

 as we have been able to find, none of them except Wolbach 

 have advocated it. Tn the introduction to his article describing 

 this method, Sellards (1904) makes the statement that up to that 

 time no one had recommended the use of phosphorus for anaero- 

 bic work, although phosphorus is one of the most powerful ab- 

 sorbing agents of oxygen. Among the recommendations for its 

 use, this author mentions that phosphorus is very convenient, 

 that it requires no previous preparation, that it keeps well, and 

 that its absorbing efficiency is very easily tested. 



He mentions two possible diffi.culties; first, that the oxides of 

 phosphorus formed during the absorption of oxygen might change 

 the reaction of the medium employed; second, that the vapors 

 of the elementary phosphorus might injure the nutrient media. 

 He mentions not having had any difficulty from these sources. 



The phosphorus method has been used in this laboratory for 

 the past three years and we wish to recommend it for the cul- 

 tivation of anaerobic bacteria. We have been able to culture 

 all obhgate anaerobes, which we have tried upon the surface of 

 plates and slant agar. Obligate anaerobes also grow well in liquid 

 media under anaerobic conditions produced by phosphorus. 

 We have had no diffi.culty concerning the injur\' to the media. 

 There is a slight rise in temperature within the jar as the phos- 

 phorus burns; this, however, exerts no detrimental effect upon 

 the cultures. One great advantage of this method over others 

 is that the power of phosphorus to absorb oxygen is so great that 

 a rather small amount will absorb the oxygen within the jar, 

 and enough will remain to absorb whatever may leak in during 

 the incubation period. Sellards recommended the presence of 

 an excess of alkali to absorb the phosphorus acid anhydrides. 

 We have found that water serves the same purpose almost equally 

 well. There is some theoretical objection to burning the phos- 

 phorus in the jar, in that elementary phosphorus is volatilized. 

 We have had no difficulty from this source as far as the growth 

 of bacteria is concerned, but some of the material is deposited 



