Wishing to ascertain what difference there would be if the inoculated fluids were exposed for a very long time, instead of for ten minutes only, to certain temperatures, I prepared three flasks in the same manner--each containing some of the previously boiled solution, which, when cold, had been inoculated with living _Bacteria_, _Vibriones_, and _Torulæ_. These flasks and their contents were then submitted to the influence of the following conditions:--One of them was heated for a few minutes in a beaker containing water at 113° F., and then by means of the air-pump a partial vacuum was procured, till the fluid began to boil. After the remainder of the air had been expelled by the ebullition of the fluid, the neck of the flask was hermetically sealed, and the flask itself was subsequently immersed in the water of the beaker, which was kept for four hours at a temperature between 113° and 118-1/2° F.[41] The two other flasks similarly prepared were kept at a temperature of 118-1/2° - 127-1/2° F. for four hours. In two days, the fluid in the first flask became slightly turbid, whilst in two days more the turbidity was most marked. The fluid in the two other flasks which had been exposed to the temperature of 118-1/2° - 127-1/2° F. for four hours, remained quite clear and unaltered during the twelve days in which they were kept in the warm bath under observation. These experiments seem to show, therefore, that the prolongation of the period of exposure to four hours, suffices to lower the vital resistance to heat of _Bacteria_ and _Torulæ_ by 14-1/2° - 18° F. [41] During nearly the whole of the time the temperature was kept at 113° F. It only rose to the higher temperature for about ten minutes.