Comparative Studies on Respiration. Iii. the Effect of Ether on the Respiration and Growth of Bacillus Subtilis. by Matilda

Although so much stress is laid on the physiological reactions of bacteria in their identification and classification, little investigation (except to distinguish aerobic from anaerobic forms) has been devoted to the fundamental process of respiration in these organisms. In order to throw some light on the nature of this process and to compare the results with those obtained with other plants and with animals, a series of studies upon the respiration of bacteria has been undertaken. The present paper describes the results of some experiments on the effects of ether. The organism selected for experimentation was Bacillus subtilis, isolated from water and inoculated upon agar-agar daily during the month previous to experimentation, so that a pedigreed culture was at hand. Several other organisms were tried; namely, Bacillus mycoicles, Staphylococcus pyogenes albus, Staphylococcus citreus, Bacillus typhosus; but Bacillus subtilis was preferred because it was easier to handle. Bacteria were incubated for 16 to 18 hours at 37°C. and were then washed into a test-tube with a few cc. of tap water containing indicator. A thick emulsion was made by repeatedly drawing the liquid into, and ejecting it from a pipette which was drawn out to a very fine point. The respiration of the bacteria was tested in boiled tap water. The boiling rendered the water alkaline by driving off the COs. To each 2 cc. of solution was added one drop of a 0.01 per cent aqueous solution of phenolsulfonephthalein. The color of the solution was compared with the colors of a set of standard buffer solutions, made according to SSrensen's directions with KH~PO4 and Na2HPO4, hay193