*No. XLVIII.--Ammonic Acetate Solution.*--On the tenth day the fluid was still quite clear, and free from sediment. *No. XLIX.--Ammonic Oxalate Solution.*--On the tenth day there was no distinct opalescence of the fluid, but a well-marked whitish flocculent deposit. On microscopical examination no _Bacteria_ were found in the fluid, and the deposit was made up by an aggregation of blackish and colourless granules, mixed with a few crystals and a very few _Torula_ cells--all being held together by a sort of mucoid matrix. In the midst of this matter were found two or three very small, much branched, mycelial tufts of a fungus-growth. *No. L.--Ammonic Carbonate Solution.*--On the tenth day the fluid showed a very faint opalescence, with a small amount of deposit, and a partial non-coherent scum on the surface, which, on microscopical examination, was found to be composed partly of amorphous granules, and partly of minute _Bacteria_, mixed with small necklace-like organisms. The fluid itself contained, in suspension, a few small and sluggish _Bacteria_, with a minute _Torula_ cell here and there. *No. LI.--Ammonic Tartrate Solution* after twenty-four hours showed the faintest opalescence of the fluid; in forty-eight hours there was a bluish-white turbidity, and in seventy-two hours the turbidity was well marked. When examined microscopically the fluid was found to contain multitudes of very active _Bacteria_. On the thirteenth day the turbidity was not so well marked, though there was a very thin pellicle on the surface, and also the dirty-looking crumpled remains of another pellicle at the bottom, which, on examination, was found to be composed of an aggregation of _Bacteria_. The pellicle on the surface was very thin, and composed only of a single layer of _Bacteria_. In the fluid itself many _Bacteria_ were seen, of medium size, and mostly sluggish in movement, though a few of them exhibited very active rotatory movements. No _Vibriones_, _Leptothrix_, or _Torulæ_, were found. *No. LII.--Ammonic Tartrate and Sodic Phosphate Solution* after twenty-four hours showed the faintest opalescence; in forty-eight hours there was a bluish-white turbidity, which, in seventy-two hours, had become more marked. When examined microscopically multitudes of _Bacteria_ were found whose movements were very sluggish. On the thirteenth day there was a well-marked whitish turbidity, due to _Bacteria_ and _Vibriones_, a slight amount of deposit, and a firm pellicle which was found to be composed, almost wholly, of long unjointed _Vibriones_ and unsegmented _Leptothrix_ filaments, all of which, when separate, exhibited the most distinct eel-like movements, accompanied by an actual progression from place to place. _Ammoniacal Solutions, unboiled, and exposed to Air in a Corked Bottle, after Inoculation with a Drop of Fluid containing living_ BACTERIA_and_ TORULÆ. (_Temp._ 60°–65° F.)