examination of the fluid no living _Bacteria_ were to be found. This particular experiment was repeated three times with similarly negative results, although on two occasions the fluid was only boiled for one minute instead of ten. [32] In the proportion of ten grains of neutral ammonic tartrate, with three grains of neutral sodic phosphate, to an ounce of distilled water. It seemed, moreover, that by having recourse to experiments of the same kind, the exact degree of heat, which is fatal to _Bacteria_ and _Torulæ_ might be ascertained. I accordingly endeavoured to determine this point. Portions of the same saline solution, after having been boiled[33] and allowed to cool, were similarly inoculated with a drop[34] of very turbid fluid, containing hundreds of living _Bacteria_, _Vibriones_, and _Torulæ_. A drying apparatus was fixed to an air-pump, and the flask containing the inoculated fluid was securely connected with the former by means of a piece of tight india-rubber tubing,[35] after its neck had been drawn out and narrowed, at about two inches from the extremity. The flask containing the inoculated fluid was then allowed to dip into a beaker holding water at 122° F., in which a thermometer was immersed. The temperature of the fluid was maintained at this point for fifteen minutes,[36] by means of a spirit lamp beneath the beaker. The air was then exhausted from the flask by means of the pump, till the fluid began to boil; ebullition was allowed to continue for a minute or two, so as to expel as much air as possible from the flask, and then, during its continuance, the narrowed neck of the flask was hermetically sealed by means of a spirit-lamp flame and a blowpipe. Other flasks were similarly prepared, except that they were exposed to successively higher degrees of heat--the fluid being boiled off, in different cases, at temperatures of 131°, 140°, 149°, 158°, and 167° F. All the flasks being similarly inoculated with living _Bacteria_, _Vibriones_, and _Torulæ_, and similarly sealed during ebullition, they differed from one another only in respect to the degree of heat to which they had been submitted. Their bulbs were subsequently placed in a water bath, which during both day and night was maintained at a temperature of from 85° to 95° F. The results have been as follows:--The flasks whose contents had been heated to 122° and 131° F. respectively, began to exhibit a bluish tinge in the contained fluid after the first or second day; and after two or three more days, the fluid in each became quite turbid and opaque, owing to the presence and multiplication of myriads of _Bacteria_, _Vibriones_ and _Torulæ_; the fluids in the flasks, however, which had been exposed to the higher temperature of 140°, 149°, 158°, and 167° F., showed not the slightest trace of turbidity, and no diminution in the clearness of the fluid while they were kept under observation--that is, for a period of twelve or fourteen days.