No. XVI.—Simple Turnip Infusion in twenty-four hours had undergone no apparent change. In thirty-six hours there was slight turbidity, and in forty-eight hours this was most marked and uniform. When the flask was opened, after seventy-two hours, there was an outrush of very fœtid gas; the reaction of the fluid was acid, and, when examined microscopically, it was found to contain multitudes of very languid Bacteria.
No. XVII.—Neutralized Infusion of Turnip + 1/2 gr. of Cheese,[53] in thirty-six hours showed a well-marked pellicle.[54] When the flask was opened, after seventy-two hours, there was a violent outrush of gas, though the fluid was still neutral. Portions of the thick pellicle were found, on microscopical examination, to be made up of Bacteria, Vibriones, and an abundance of long, interlaced Leptothrix filaments. Bacteria also existed abundantly in the fluid, though their movements were very languid.
c. Fluid in a Bent Neck Flask, having Eight acute Flexures.
No. XVIII.—Simple Turnip Infusion after forty-eight hours showed no change. It was kept in water-bath for twelve days, and during the whole of this time the fluid remained quite clear. The tube was then broken 1 1/2 inch above the bulb (which was re-immersed in the bath), leaving the fluid exposed to the air through the straight open tube. The fluid at this time was odourless, and its re-action was still faintly acid.
The infusion remained thus exposed for six days without undergoing any apparent change. On the eighth day a very slight whitish sediment was noticed, which had increased in quantity by the tenth day, though there was still no trace of general turbidity. On the eleventh day some of the sediment was examined in a drop of the fluid, and it was found to be wholly composed of rather large Torulæ cells—the largest being about 1/3000 in diameter, though all the smaller sizes were abundantly represented. Not a single Bacterium or Vibrio could be detected, and the fluid was still quite odourless.[55]
No. XIX.—Neutral Turnip Infusion + 1/2 gr. of Cheese, showed no perceptible change in twenty-four hours, though in thirty-six hours there was a well-marked pellicle on the surface. When the neck of the flask was broken after seventy-two hours, the fluid was found to be very fœtid, whilst its re-action had become slightly acid. Portions of the pellicle were found to be made up by aggregations of Bacteria, Vibriones, and an abundance of Leptothrix filaments. The Bacteria all exhibited very languid movements.
e. Fluid (in vacuo) in a Flask which had been Sealed during Ebullition.
No. XX.—Simple Turnip Infusion in twenty-four hours showed a very slight amount of turbidity; in thirty-six hours this had increased, and in forty-eight hours there were multitudes of curdy flocculi floating in a tolerably clear fluid. The flask was opened after seventy-two hours, when there seemed to be only a very slight inrush of air. The odour of the fluid was somewhat fœtid, and its re-action was acid. There were multitudes of Bacteria and Vibriones, partly separate and partly aggregated (constituting the flocculi above mentioned). The separate Bacteria exhibited only very languid movements.
No. XXI.—Neutral Turnip Infusion + 1/2 gr. of Cheese, showed a well-marked pellicle on its surface in twenty-four hours. In thirty-six hours the first pellicle had, in great part, sunk to the bottom of the flask, though its place on the surface was already taken by a new, though thin, scum-like layer. After seventy-two hours, the flask was opened; there was no fœtid odour of the fluid, and its re-action was still neutral. Examined microscopically the fluid showed an abundance of Bacteria, and also of short monilated filaments. There were, however, none of the ordinary kind of Vibriones, and no Leptothrix. All the Bacteria exhibited very languid movements.