82 



MANUAL OF BACTERIOLOGY. 



The inconvenience and danger of sealing the tubes in the 

 flame, as has to be done in Liborius-Frankel's and other 

 methods for cultivation under hydrogen, are obviated in Novy's 

 apparatus. The tubes or plates are placed in jars through 

 which hydrogen may be conducted. The stopper, having been 

 smeared previously with a soft wax, is sealed by giving it one- 

 fourth of a turn. 



There have been various other kinds of apparatus, usually 



complicated and expen- 

 sive, devised for the growth 

 of plate-cultures under 

 hydrogen, but Novy's jars 

 are the best, both for tubes 

 and for plates. 



Other expedients for the cul- 

 tivation of anaerobic bacteria are 

 less eflfective. In cases where a 

 very deep stab-culture is made in 

 gelatin or agar, where the growth 

 appears in the lower part of the 

 tube by preference, it is supposed 

 to be anaerobic. Koch covered 

 part of the surface of a gelatin 

 plate with a bit of sterilized mica 

 or a cover-glass; bacteria which 

 grew beneath this plate were con- 

 sidered to be anaerobic. An- 

 other method was to cover the 

 surface of the gelatin in the 

 culture-tube with sterilized oil. W. H. Park has recommended a mixture of 

 solid paraflSn with 25 to 50 per cent, of fluid parafSn or albolene as a covering 

 for the surface of anaerobic cultures. This mixture has a semisolid consis- 

 tency, and does nor retract at the edges on cooling. The parafiin prevents the 

 absorption of oxygen, except to a small extent at the edges. The method is 

 useful for large quantities of culture material, as in flasks. Esmarch advised 

 making roll-tubes, and after cooling them to fill them with a melted gelatin 

 cooled down to near the point of solidification. Hueppe made use of eggs in 

 their shells. The egg-shell was carefully cleaned, sterilized with a solution of 

 bichloride of mercury, washed with sterilized water and wiped dry with steril- 

 ized cotton. The end of the egg-shell was punctured with a hot needle 



Fig. 28. — Novy's Jar for the CultI' 

 VATION OE Anaerobes. 



