Harvard classics . bove the tap. We then openedthe tap, and some of the liquid in the funnel entered theflask, carrying with it the small deposit of yeast, which wassufficient to impregnate the saccharine liquid contained inthe flask. In this manner it is possible to introduce assmall a quantity of yeast as we wish, a quantity the weightof which, we may say, is hardly appreciable. The yeastsown multiplies rapidly and produces fermentation, thecarbonic gas from which is expelled into the mercury. Inless than twelve days all the sugar had disappeared, and thefermentation had finished. There was
Harvard classics . bove the tap. We then openedthe tap, and some of the liquid in the funnel entered theflask, carrying with it the small deposit of yeast, which wassufficient to impregnate the saccharine liquid contained inthe flask. In this manner it is possible to introduce assmall a quantity of yeast as we wish, a quantity the weightof which, we may say, is hardly appreciable. The yeastsown multiplies rapidly and produces fermentation, thecarbonic gas from which is expelled into the mercury. Inless than twelve days all the sugar had disappeared, and thefermentation had finished. There was a sensible deposit ofyeast adhering to the sides of the flask; collected and dried 2 Capable of living without free oxygen—a term invented by Pasteur.—Ed, THEORY OF FERMENTATION 293 it weighed grammes (34 grains). It is evident that inthis experiment the total amount of yeast formed, if it re-quired oxygen to enable it to live, could not have absorbed,at most, more than the volume which was originally held. Fig. 1 m solution in the saccharine liquid, when that was exposedto the air before being introduced into the flask. Some exact experiments conducted by M. Raulin in ourlaboratory have established the fact that saccharine worts,like water, soon become saturated when shaken briskly withan excess of air, and also that they always take into solutiona little less air than saturated pure water contains under thesame conditions of temperature and pressure. At a tempera-ture of 250 C. (770 R), therefore, if we adopt the coefficientof the solubility of oxygen in water given in Bunsens tables,we find that 1 litre (1% pints) of water saturated with aircontains cc. ( cubic inch) of oxygen. The three litresof yeast-water in the flask, supposing it to have been satu-rated, contains less than cc. (1 cubic inch) of oxygen,or, in weight, less than 23 milligrammes ( grains). This 294 LOUIS PASTEUR was the maximum amount of oxygen, supposing the greatestpossible quanti
Size: 1645px × 1518px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1910
