Studies on fermentation : the diseases of beer, their causes, and the means of preventing them . 17 in.] STUDIES ON FERMENTATION. 301 On June 28th, fermentation was quite finished ; there wasno longer any trace of gas, nor any lactate in solution. Allthe infusoria were lying motionless at the bottom of the flask-The liquid clarified by degrees, and in the course of a few daysbecame quite bright. Here we may inquire, were thesemotionless infusoria, which from complete exhaustion of thelactate, the source of the carbonaceous part of their food, werenow lying inert at the bottom of the fermenting
Studies on fermentation : the diseases of beer, their causes, and the means of preventing them . 17 in.] STUDIES ON FERMENTATION. 301 On June 28th, fermentation was quite finished ; there wasno longer any trace of gas, nor any lactate in solution. Allthe infusoria were lying motionless at the bottom of the flask-The liquid clarified by degrees, and in the course of a few daysbecame quite bright. Here we may inquire, were thesemotionless infusoria, which from complete exhaustion of thelactate, the source of the carbonaceous part of their food, werenow lying inert at the bottom of the fermenting vessel—werethey dead beyond power of revival ? * The following experi-ment leads us to believe that they were not perfectly lifeless,and that they behave in the same manner as the yeast of beer,which, after it has decomposed all the sugar in a fermentableliquid, is ready to revive and multiply in a fresh saccharinemedium. On April 22nd, 1875, we left in the oven, at atemperature of 25° C. (77° F.), a fermentation of lactate oflime that had been completed. The delivery tube of the flask,. Fig. 73. The carbonaceous supply, as we remarked, had failed them, and totliis failure tlie absence of vital action, nutrition, and multiplication wasattributable. The Liquid, however, contained butpate of lime, a saltpossessing properties similar to those of the lactate. Why could notthis salt equally well support the life of the vibrios ? The explanation ofthe difficulty seems to us to lie simply in the fact that lactic acid producesheat by its decomposition, whilst butyric acid does not, and the vibriosseem to require heat during the chemical process of their nutrition. 302 STTiniES ON FERMEXTATIOX. A, (Fig. 73) in which it had taken place had never been with-drawn from under the mercury. We kept the liquid underobservation daily, and saw it gradually become brighter ; thiswent on for fifteen days. We then filled a similar flask, B,with the solution of lactate, which we boiled, not only
Size: 1967px × 1270px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1870, bookpublisherlondo, bookyear1879
