THEORY OF FERMENTATION 



295 



conducted, determining the quantity of oxygen that remained 

 in solution in the liquid after cooling, according to M. Schiit- 

 zenberger's valuable method, by means of hydrosulphite of 

 soda, 8 we found that the three litres in the flask, treated as 

 we have described, contained less 

 than one milligramme (0.015 grain) 

 of oxygen. At the same time we 

 conducted another experiment, by 

 way of comparison (Fie. 3). We 

 took a flask, B, of larger capacity 

 than the former one, which we 

 filled about half with the same 

 volume as before of a saccharine 

 liquid of identically the same com- 

 position. This liquid had been 

 previously freed from alterative 

 germs by boiling. In the funnel 

 surmounting A, we put a few cubic 

 centimetres of saccharine liquid in 

 a state of fermentation, and when 

 this small quantity of liquid was 

 in full fermentation, and the yeast 

 in it was young and vigorous, we 



FIG. 3 



opened the tap, closing it again immediately, so that a little 

 of the liquid and yeast still remained in the funnel. By this 

 means we caused the liquid in A to ferment. We also im- 

 pregnated the liquid in B with some yeast taken from the 

 funnel of A. We then replaced the porcelain dish in which 

 the curved escape tube of A had been plunged, by a vessel 

 filled with mercury. The following is a description of two 

 of these comparative fermentations and the results they gave. 



The fermentable liquid was composed of yeast-water 

 sweetened with 5 per cent of sugar-candy; the ferment 

 employed was sacchormyces pastorianus. 



The impregnation took place on January 20th. The flasks 

 were placed in an oven at 25 (77 F.). 



Flask A, without air. 



January aist. Fermentation commenced; a little frothy liquid 

 fatoed from the escape tube and covered the mercury. 



NaHSOa, now called Sodium hyposulphite. D. C. It 



