No. XL.—Hay Infusion had become quite turbid in twenty-four hours, and several shades lighter in colour. After forty-eight hours the colour of the infusion was still lighter; there was more turbidity, and some sediment. On microscopical examination, the fluid was found to contain an abundance of Bacteria, Vibriones and short Leptothrix filaments.
No. XLI.—Hay Infusion + 1/20 of Carbolic Acid showed no apparent change[65] after forty-eight hours, and when examined microscopically it revealed no trace of Bacteria, or other organisms. The neck of the flask was then again closed. On the twelfth day the fluid had still undergone no change in appearance, and when examined microscopically, it still showed no trace of organisms, though the fluid was—as it had been at the time of the first examination—full of minute, undissolved particles of carbolic acid.
Fluids boiled for five minutes, and half-filling hermetically Sealed Flasks containing Ordinary Air.
No. XLII.—Hay Infusion, after forty-eight hours, showed no change, and continued to remain quite clear and free from deposit until the twelfth day, when it was examined microscopically. No organisms of any kind could be detected.
No. XLIII.—Hay Infusion + 1/20 part of Carbolic Acid showed no apparent change[66] for the first five days, though, on the sixth day, a slight deposit was noticed at the bottom of the flask. The deposit had increased, and was well-marked by the twelfth day, when, on microscopical examination, there were found amongst the granular flakes of the deposit, Torulæ of several varieties of size and shape. Many were spherical, others ovoid, or having an elongated oat-like shape: some were of the ordinary colour, and others were brownish in tint. The variety was most striking. No Bacteria were seen, though there were multitudes of active particles which seemed to differ from the minute spherules of undissolved carbolic acid.
Fluids (in vacuo)—boiled for five minutes, and Flasks Sealed during Ebullition.
No. XLIV.—Turnip Infusion, in seventy-two hours, showed a slight turbidity, which gradually increased. On the eighth day there was a considerable quantity of flake-like sediment, and some amount of general turbidity. On the thirteenth day the vacuum was found to be still partly preserved. When the flask was opened the fluid was perceived to have a fœtid odour, and an acid re-action; and, on microscopical examination, multitudes of Bacteria and Vibriones were seen. In the flake-like aggregations also (made up almost wholly of these organisms) there were a number of large thick-walled spores; some already formed, and others in process of formation by coalescence.
No. XLV.—Turnip Infusion + 1/20 part of Carbolic Acid showed no increase of turbidity[67] for the thirteen days during which it was kept under observation. Before the flask was opened it was ascertained that the vacuum was well preserved. The odour of the fluid was unaltered, and on microscopical examination no Bacteria, or other living things, were found.[68]
No. XLVI.—Hay Infusion, after forty-eight hours, showed no change, though, in seventy-two hours, there was perceptible a very small amount of a dirty greyish deposit. By the fifth day the deposit had slightly increased, and on the seventh day there was a trace of turbidity in the fluid. It did not undergo much further change, so that, on the twelfth day, the flask was opened. The vacuum was found to have been very slightly impaired; the odour of the fluid was almost natural, and its re-action was slightly acid. On microscopical examination of the deposit, Bacteria, Vibriones, short Leptothrix filaments, and Torulæ, were found, though not in very great abundance.
No. XLVII.—Hay Infusion + 1/20 part of Carbolic Acid showed no apparent change for the first four days. On the fifth day there was a small quantity of powder-like sediment, and one dirty greyish-coloured flake. On the seventh day there were more small flakes at the bottom, and a slight general turbidity of the fluid. On the twelfth day, the turbidity and deposit having increased, the flask was opened—after it had been first ascertained that the vacuum had only been slightly impaired. The re-action of the fluid was still strongly acid. On microscopical examination of some of the deposit, there was found, amongst granular flakes and aggregations, a large number of Torulæ cells, of most various shapes and sizes; also in the midst of the granule heaps many large, rounded or ovoidal, densely granular nucleated bodies, whose average size was 1/1500″ in diameter, though there were many of them much larger, and others even less than half this size. Intertwined amongst the granular matter also were a large number of algoid-looking filaments, 1/20000 in diameter, containing segmented protoplasmic contents. There were also in the fluid itself a number of medium-size, unsegmented Bacteria, whose movements were somewhat languid.[69]