[Illustration with caption:  Fig. 9]

Next day we applied a finger to the open extremity of the exit-tube, which we then plunged in a vessel of mercury.  In this particular experiment which we are describing, we permitted the flask to remain in this state for a fort-night.  It might have remained there for a century without ever manifesting the least sign of fermentation, the fermentation of the tartrate being a consequence of life, and life after boiling no longer existed in the flask.  When it was evident that the contents of the flask were perfectly inert, we impregnated them rapidly, as follows:  all the liquid contained in the exit-tube was removed by means of a fine caoutchouc tube, and replaced by about 1 c. (about 17 minims) of liquid and deposit from another flask, similar to the one we have just described, but which had been fermenting spontaneously for twelve days; we lost no time in refilling completely the exit tube with water which had been first boiled and then cooled down in carbonic acid gas.  This operation lasted only a few minutes.  The exit-tube was again plunged under mercury.  Subsequently the tube was not moved from under the mercury, and as it formed part of the flask, and there was neither cork nor india-rubber, any introduction of air was consequently impossible.  The small quantity of air introduced during the impregnation was insignificant and it might even be shown that it injured rather than assisted the growth of the organisms, inasmuch as these consisted of adult individuals which had lived without air and might be liable to be damaged or even destroyed by it.  Be this as it may, in a subsequent experiment we shall find the possibility removed of any aeration taking place in this way, however infinitesimal, so that no doubts may linger on this subject.

The following days the organisms multiplied, the deposit of tartrate gradually disappeared, and a sensible ferment action was manifest on the surface, and throughout the bulk of the liquid.  The deposit seemed lifted up in places, and was covered with a layer of dark-grey colour, puffed up, and having an organic and gelatinous appearance.  For several days, in spite of this action in the deposit, we detected no disengagement of gas, except when the flask was slightly shaken, in which case rather large bubbles adhering to the deposit rose, carrying with them some solid particles, which quickly fell back again, whilst the bubbles diminished in size as they rose, from being partially taken into solution, in consequence of the liquid not being saturated.  The smallest bubbles had even time to dissolve completely before they could reach the surface of the liquid.  In course of time the liquid was saturated, and the tartrate was gradually displaced by mammillated crusts, or clear, transparent crystals of carbonate of lime at the bottom and on the sides of the vessel.