176 
PROFESSOR TYNDALL ON THE DEPORTMENT AND VITAL 
To the latter, it will be remembered, the air had access through the plug of cotton- 
wool, while to the former no air had access, save the small quantity imprisoned above 
the infusion when the necks of the bulbs were sealed. The aerated bulbs grew rapidly 
and thickly turbid, while a passing cloudiness was all that showed itself in the sealed 
ones. This soon disappeared, and left the infusions apparently intact. In fact it 
required some attention to detect the appearance of this fugitive life, which existed 
only so long as there was oxygen to sustain it. I have ranged the sealed and unsealed 
tubes side by side in groups. To the most cursory observation the difference between 
them is obvious. The experiment strikingly illustrates the dependence of the special 
organisms here implicated on the oxygen of the air. 
The experiments were pushed still further on £he 28th of December. Two bulbs of 
cucumber, two of melon, two of turnip, and two of artichoke were then plugged, sealed, 
and maintained at the boiling temperature for four hours. Six of the eight bulbs 
burst in the operation, but two of them, a bulb of melon and one of cucumber, bore 
the ordeal uninjured. After cooling, their sealed ends being broken off, they were 
placed in the warm room. The melon remained permanently sterile, but in two days 
the cucumber-infusion became turbid and laden with fatty scum. 
Eight similar bulbs were boiled on the same day for five hours and a half. Four of 
them burst, but four remained intact. Of these, two contained cucumber-, one melon-, 
and one turnip-infusion. Three out of the four bulbs were sterilized by the long- 
continued boiling, but one cucumber-bulb passed through the ordeal unscathed. Tw r o 
days after the operation it swarmed with life, and was covered with a fatty scum formed 
of matted Bacteria. 
Many similar experiments were subsequently made. On the 27th of January, for 
example, six bulbs of turnip-infusion were boiled for 220 minutes, six for 300 minutes, 
and two for 30ft minutes. Suspended in the air above each infusion was a sprig of old 
Colchester hay, this being purposely introduced to augment the chance of infection. 
Notwithstanding its presence the bulbs were one and all permanently sterilized. The 
specific gravity of the infusion was in all cases 1007. 
The sprigs of old hay were afterwards shaken into the liquid, but they produced no 
effect. For weeks afterwards the infusion remained clear. Was this impotence to 
generate life due to the fact that the nutritive power of the infusion had been destroyed 
by the “blighting influence of heatl” Not so; for when the same infusion was 
infected by a sprig of fresh hay. by a small pellet of cotton-wool rubbed against the 
dusty shelves of the warm room, or by a speck of another infusion containing Bacteria , 
it never failed to develop life. The only observed difference between the effect pro- 
duced by the dry hay or dust and the living Bacteria was purely a difference of time. 
Inoculation with the finished organisms acted more rapidly than infection with the 
dust, but the effects were the same in the end. 
On the 27th of January also nine melon-bulbs were treated exactly like the turnip, 
being furnished with sprigs of old Colchester hay, plugged with cotton-wool, and 
