EXPERIMENT STATION BULLETINS. 



301 



In the first determination the culture had stood much longer than in the second, — 

 in the first case six weeks, in the second about three weeks. The difference in time 

 alters the relation of carbonic acid gas and hydrogen. This was borne out by further 

 tests which showed the variability in the relation of carbonic acid gas to hydrogen. 

 A study in the formation of gas by the action of this bacillus upon other substances 

 may lend interest to the investigation. Tlio Smith fermentation-tube was used in this 

 instance and the relation of carbonic acid gas and hydrogen to each other was deter- 

 mined. It was at the same time compared with a stock-colon bacillus which had been 

 in the laboratory for some time. For this determination yeast water was preferably 

 used to ordinary bouillon because of the greater accuracy, and to this was added 

 two per cent of each of the substances employed. These will be represented in the 

 following table: 



Bacillus Bacillus 



of gassy coli 



curd.' communis. 



Maltose H/Co2=f H/Co2=:| 



Lactose H/ Co2=:| H/Coo=^ 



Cane-sugar H/Co2=i H/Coo=f 



Leviilose H/Oo2=} H/Co2=f 



Glucose H/Co,= i H/Coa=i 



Note. — Owing- to the impurities so frequently present in sugars and other carbohydrates, the author 

 does not regard the above table as valuable in any other respect than indicating the possible range of 

 this bacillus' activity. 



Fig. 3. [Gassy curd starter.] 



Yeast water (as checks) yielded no gas — the action is therefore entirely on above 

 substances. These tubes were treated to the same conditions for twenty-four hours at 

 incubator temperature, 37 y, degrees C. (98 degrees F.). 



In a comparison of glucose and lactose of two per cent strength in each case, the 

 glucose produced twice as much gas as the lactose in the same length of time. This 

 micro-organism ferments glucose more readily, as is usually the case. 



What evidences have been brought out in the investigations of the gas produced do 

 in no wise tell us the relation of these gases in the cheese itself and the facts given 

 may only by analogy be carried over. Under the conditions found in cheese, 

 anaerobiosis, nitrogenous matter in abundance, and sugar in scarcity, the relation 

 of the gases may be entirely changed about and partake of another nature. This is an 



