Fourth Set of Experiments (XXXI.–XXXVII.).
b. Fluid in contact with ordinary Air and its Particles; Flask Sealed after the Fluid had become Cold.
No. XXXI.—Healthy Urine remained in the warm bath for twenty-eight days without undergoing the least change.
No. XXXII.—Simple Turnip Infusion remained in the warm bath for twenty-eight days without undergoing any appreciable change.[59] On breaking the neck of the flask, the fluid was found to be quite odourless. With its neck quite open, the flask was replaced in the water-bath. During the first forty-eight hours it underwent no apparent change, though at the end of seventy-two hours a slight general turbidity was noticeable, and an examination of a drop of the fluid (still odourless), showed a number of minute but very active Bacteria.[60]
c. Fluid in a Bent-Neck Flask, having Eight acute Flexures.
No. XXXIII.—Simple Turnip Infusion showed no change after eight days’ immersion in the warm bath. After eleven days, the fluid being still clear, the tube was broken just beyond the second bending from the bulb, and then the flask was re-immersed in the bath. After three days’ exposure, the fluid being still clear, it was boiled in the flask for one minute, when it was noticed that the steam was quite odourless. The flask was then replaced in the water-bath, where it remained for twenty-two days (still with the neck open and broken just beyond its second bending) without showing any change.[61] It was then submitted to examination; the fluid was found to be devoid of all odour, it had a slightly bitter taste, and its re-action was very faintly acid. On microscopical examination no living things were found; there were no Bacteria, no Vibriones, and no Torulæ, only some mere granules, a small amount of amorphous matter, and a few fibres.[62]
No. XXXIV.—Turnip Infusion Neutralized by Ammonic Carbonate in forty-eight hours showed a slight turbidity, which slowly increased during the next two days. In two days more the turbidity was very great, and there was also a considerable amount of sediment. The fluid was then examined microscopically, and found to contain myriads of large but very languid Bacteria.
e. Fluid (in vacuo) in a Flask which had been Sealed during Ebullition.
No. XXXV.—Healthy Urine underwent no apparent change for the first twelve days, then (the bulk of the fluid still remaining clear and bright) small greyish white flocculi began to collect at the bottom of the flask, which very slowly increased in quantity during the succeeding twelve days. At the expiration of this time the flocculi were pretty numerous, though the fluid was otherwise bright. The vacuum was ascertained to be still good, and on breaking the flask, the fluid was found to have a slightly acid re-action, though no appreciable odour. When examined microscopically, the flocculi were seen to be made up for the most part of mere granular aggregations (simple, and not in the form of Bacteria). Small Torula cells, however, existed in some quantity; also a few necklace-like chains, and a comparatively small number of Bacteria, some of which were tolerably active.
No. XXXVI.—Simple Turnip Infusion after twenty-four hours showed no sign of change, though in thirty-six hours it was slightly turbid. On the fourth day the turbidity was well-marked and general, though there were no flake-like aggregations. When examined microscopically, the fluid was found to contain multitudes of Bacteria.
No. XXXVII.—Turnip Infusion,[63] Neutralized by Ammonic Carbonate in twenty-four hours was decidedly turbid. In thirty-six hours the turbidity was more marked, and there was a slight sediment. By the end of forty-eight hours both turbidity and sediment had notably increased. On the fourth day, there was a moderately clear fluid, containing an abundance of curdy or flake-like masses. When the flask was opened, these were found to be made up principally by the aggregation of myriads of Bacteria.