The enzymes concerned in the decomposition of glucose and mannitol by Bacillus coli communis . Part III.—Various phases in the decomposition of glucose by an emulsion of the organisms

In Part II of this series results have been described which indicate the existence of several independent processes occurring during the one experiment. The experiment which will be now described was undertaken with the object of simplifying results by shortening the time of the fermentation. Arrangements were made also to count the bacteria at various periods, with the object of determining how far the fermentation was due to enzyme action which could be said to be carried on independent of the multiplication of the cells. The plan of the experiment was as follows:—About 50 grm. of glucose was to be fermented in a volume of 5 litres of solution. A sample of about a litre was to be removed every 12 hours and submitted to analysis. By a comparison of these analyses the amounts of the various products which had been formed during each interval of time would he determined. Certain modifications were necessary in the form of apparatus used and in regard to the analysis. With regard to the analysis, the estimation of carbon dioxide from time to time during the course of the experiment required a special device. In the first place, the gas space above the solution would gradually increase as the samples of solution were removed, and diffusion from the solution to the space above would cause the con­centration of CO2 in the solution to be constantly changing, and in the second place, since the sample of the fermentation solution would have to be removed while warm, precautions would have to be taken to avoid loss of CO2 prior to its mixture with standard barium hydroxide solution. The apparatus was therefore arranged according to the plan represented in the figure below.