66 METHODS OF CULTIVATION OF BACTERIA. 



into it as would be used in the Esmarch roll-tube method. 

 It is corked with an india-rubber stopper having two tubes 

 passing through it, as in Fig. 22. The ends of the 

 tubes are partly drawn out as shown, and covered with 

 plugs of cotton wool. Three such tubes are prepared, and 

 they are sterilised in the steam steriliser (p. 37). After 

 sterilisation the gelatine is melted and one tube inoculated 

 with the mixture containing the 

 anaerobes ; the second is inoculated 

 from the first, and the third from the 

 second, as in making ordinary gela- 

 tine plates. After inoculation the 

 gelatine is kept liquid by the lower 

 ends of the tubes being kept in 

 water at about 30 C, and hydrogen 

 is passed in through tube x for 

 twenty minutes. The gas -supply 

 tubes are then completely sealed 

 off at x and /, and each test-tube 

 is rolled as in Esmarch's method 

 till the gelatine solidifies as a thin 

 layer on the internal surface. A 

 little hard paraffin may be run 



FIG. 22. Esmarch's roll- 

 tube adapted for culture con- 

 taining anaerobes. 



between the rim of the test-tube and the stopper, and round 

 the perforations for the gas -supply tubes, to ensure that 

 the apparatus is air-tight. The gelatine is thus in an 

 atmosphere of hydrogen in which the colonies may develop. 

 The latter may be examined and isolated in a way which will 

 be presently described. The method is admirably suited 

 for all anaerobes which grow at the ordinary temperature. 



(b] In glucose agar (Vignal's method). Three pieces 

 of ordinary quill-tubing (bore about inch) about a foot 

 long are taken, the ends are tapered in the gas flame, and 

 they are sterilised either by method A (2) (p. 36), or simply 

 by passing backwards and forwards through the flame till 

 they are very hot. Three ordinary test-tubes, a, b, c, of 

 glucose agar are now boiled in a beaker, cooled to 42 C., 

 and inoculated with the bacterial mixture as for plate 





