STUDIES ON FERMENTATION. 69 



that we were obliged to open the neck to avoid an explosion. 

 We append a sketch of its ferment (Fig. 10). 



o ^ 



Fig. 10. 



The other flask with the white streaks showed no signs of 

 any fermentation. 



In this kind of observation we rarely succeed in obtaining 

 active ferments, the reason being that we deal with volumes of 

 air that are too limited for the few germs of ferment that exist 

 in a state of suspension in it. 



We are more sure of success if we expose a tolerably large 

 surface of saccharine liquid to the open air, because, under such 

 circumstances, even if the exposure is of short duration, a con- 

 siderable volume of air will pass over the surface of the liquid. 



On May 29th, 1873, at five o'clock in the afternoon, we placed 

 in the underground room previously mentioned, at a height of 

 about two feet, ten porcelain dishes having surfaces of from 

 thirty-five to forty square inches. We had just taken them 

 from boiling water, and after allowing them to cool we placed 

 in each quantities of wort to about one-third of an inch deep, 

 which we poured from bottles uncorked with every precaution 

 against the chance of the wort coming into contact with anything 

 besides the floating particles of dust. On May 30th, at five o'clock, 

 that is after twenty-four hours of exposure to the air of the room, 

 we emptied the contents of the basins separately into glass 

 flasks with long necks, which had been treated with boiling 



