SEPARATION OF ANAEROBIC ORGANISMS 63 



Bunsen flame, and should have a small plug of cotton wool in it to filter 

 the hydrogen ^enn-l'ree. 



1'i/fOf/allate of Potassium for Anaerobic Cultures. In arranging for the 

 absorption of oxygen by this substance the proportions used in Bulloch's 

 -r] .nation method may be employed. Here 109 grans, solid caustic 

 potash are dissolved in 145 c.c. water, and to this 2-4 grms. pyrogallol 

 art- added. 



Separation of Anaerobic Organisms. (a) By Roll-tubes. 

 A 1 j inch test-tube has as much gelatin put into it as would be 

 used in the Esmarch roll-tube method. It is corked with an 

 indiarubber stopper having two tubes passing through it, as in 

 Fig. "22. The ends of the tubes are partly drawn out as shown, 



Fit;. 2L Apparatus for supplying hydnuren for anaerobic cultures. 



(t. Ki)>i>'> apparatus for manufacture of Imlro.uvn. l>. Wash-bottle con- 



taininu- 1 -It) solution ot lead :n-etate. <. Wa^h-bolt I< ulainiii^ 1-10 solution 



of silver nitrate. </. Wash-bottle containing: 1-10 solution of pyro^allic acid. 

 (l>, c, and </ are intentionally drawn to a larger scale than n to show details.) 



and covered witli plugs of cotton wool. Three such test-tubes 

 HIV prepared, and they are sterilised in the steam steriliser (p. 28). 

 At't'-r >terilisation the gelatin is melted and one tube inoculated 

 with tin- mixture containing the anaerobes; the second is inocu- 

 lated from the first, and the third from the second, as in making 

 ordinary LTriatin plates. After inoculation the gelatin is kept 

 liquid by the lower ends of the tubes being placed in water at 

 about ''<.) ('., and hydrogen is passed in through tube ./ f'-r 

 t unity minutes. Tin- i:as-supply tubes are then completely 

 Sealed ot!' at X and /, and rarli test-tube is rolled as in Ksmareh's 

 method till the gelatin solidities as a thin layer on the internal 

 surface. A little hard parallin may be run between tin- rim of the 



