VARIATIONS IN TYPHOID BACILLI 287 



FERMENTATION REACTIONS UNDER ANAEROBIC CONDITIONS 



In the preceding experiments our cultures were grown under 

 aerobic conditions. The following experiments were carried out 

 anaerobically : 



Two methods were used in these experiments. One was a combi- 

 nation of exhaustion and absorption with pyrogallol as used in this 

 laboratory for routine work; and the other was the one devised by 

 Mcintosh and Fildes. 



For the latter method we used a glass jar, connected by means of 

 tubing with a tank of compressed hydrogen, which was inverted in a 

 larger jar filled with water to a level of two or three inches above the 

 inverted jar. The latter is held down by weights when its contents are 

 displaced by hydrogen. Another tube fitted with a clamp connects 

 this jar with the jar containing cultures. 'When everything is pre- 

 pared in the culture jar a copper gauze package containing platinum 

 asbestos is heated to redness and placed in the culture jar. The jar 

 is sealed and the clamp released gradually thus allowing the hydrogen 

 to enter the culture jar. The platinum asbestos will act as a catalyser 

 to cause combination of oxj^gen and hydrogen. 



When the oxygen in the jar is exhausted no more hydrogen will enter 

 the jar. Then we seal the glass tubing to prevent the entry of air. 



On account of its greater convenience we used the latter method 

 more frequently. 



Typhoid baciUi did not grow well under anaerobic conditions; 

 consequently all reactions in sugar media were somewhat slower 

 than under aerobic conditions. 



A. Sugar broth cultures 



We tried six strains in 0.01 per cent glucose, 1 per cent raffinose, 

 1 per cent arabinose, 1 per cent dulcitol, 1 and 2 per cent rham- 

 nose, 1 per cent xylose and 2 per cent xylose. The results were 

 as follows : 



(a) Glucose 



Aerobic: On twenty-four hours' incubation media distinctly 



showed alkalinity. 

 Anaerobic: Very slightly alkaline, even after ten days' incuba- 

 tion. 



