1744 



Journal of Applied Microscopy 



Fig. 13. 



plug with paraffin and disconnect at (e). 

 The flask is opened by heating the neck 

 in the flame and raising the plug by 

 means of the attached wire. In case of 

 very large flasks Roth covers the cotton 

 plug with a piece of rubber containing 

 an opening for the introduction of the 

 glass tube before the apparatus is con- 

 nected with the generator. This will 

 increase the pressure from within and 

 prevent any possible entrance of air 

 during the introduction of gas. 



N'iU'y (1893) devised an apparatus 

 which allows a large number of tube 

 cultures to be made simultaneously. 

 The apparatus as shown in Fig. 14 con- 

 sists of a cylinder 20x10 cm. (not 

 counting the neck). The neck carries 

 two lateral tubes. Into the neck of 

 the cylinder is fitted a glass stopper with ground surface. The glass 

 stopper also carries two perforations on opposite sides corresponding to 

 those in the neck. From the inside of the glass stopper one of the 

 perforations is connected with a glass tube, reaching nearly to the bottom 

 of the cylinder. If a gas heavier than the air is introduced, the glass 

 stopper should be turned so as to conduct the gas through the tube in the 

 interior to the bottom of the cylinder, thus allowing air to escape on top 

 through the other lateral tube. In case of a gas lighter than air, as for in- 

 stance hydrogen, it should enter the cylinder on top, 

 forcing the air out through the long tube reaching to 

 the bottom of the cylinder. 



Method. — Inoculate forty to fifty ordinary culture 

 tubes (12 to 15 cm. long). Insert loose cotton plugs 

 and cut them off at the end of the tubes. With a pair 

 of long tongs place the tubes in the cylinder, the bot- 

 tom of which is covered with cotton, cover the surface 

 of the glass stopper with paraffin or vaseline and 

 insert the latter in its place, care being taken that the 

 perforations in the stopper correspond with those in 

 the neck of the cylinder. Connect the apparatus, as 

 above directed, with the gas generator and lead the 

 exit tube into a wash bottle containing water. After 

 passing the gas through for from one to two hours, 

 carefully turn the glass stopper an angle of 90°, disconnect the cylinder and 

 put it aside for the development of the bacteria. If instead of replacement 

 by gas the cylinder is evacuated, it becomes impossible to turn the glass 

 stopper. In this case each lateral tube carries a small glass turn-cock for 



Fig. 14. 



