164 
PROFESSOR TYNDALL ON THE DEPORTMENT AND VITAL 
carefully introduced into three chambers, a chamber being devoted to each infusion. 
I thought it advisable to vary the period of subsequent boiling. One tube of the 
yellow fungus was therefore boiled for five, one for ten, and one for fifteen minutes ; 
but as it was difficult to save the infusion from waste when the boiling was long 
continued, one tube of each of the other two infusions was boiled for five minutes, 
and the other two for ten. Tubes charged with the respective infusions were exposed 
at the same time to the common air. 
In two days the outside tubes containing the red- and yellow- fungus infusion 
became turbid and covered with the fatty scum so prevalent in our laboratory this 
year. No scum had formed on the surface of the exposed tree-fungus infusion, which, 
to casual observation, appeared quite black. Closer scrutiny, however, showed that 
it transmitted the deepest red of the spectrum, and was apparently quite free 
from floating matter. It changed rapidly during the night of the 3rd, and on the 
morning of the 4th of November the bottom of this tube was found laden with a 
heavy dark-brown precipitate, while numerous dark-brown flocculi floated in the liquid 
overhead, which had become almost as clear and colourless as water. Under the 
microscope the dark-brown mass resolved itself into confused moss-like patches and 
long cylindrical sheaths dotted throughout with small dark specks. These filaments 
with spore-like specks have been of very frequent occurrence in this inquiry. 
The deportment of the closed chambers was as follows: — 1. Yellow fungus: the 
liquid in the three tubes remained perfectly and permanently clear and without a 
trace of the scum which loaded the infusion outside. 2. Eed fungus : one of the 
three tubes became thickly turbid, while the two others maintained their pristine 
brilliancy. 3. Tree fungus : one of the tubes became thickly turbid, the two others 
remained permanently clear. 
I asked myself why should one tube of the red fungus give way and the others 
remain intact'? The answer seemed at hand. The turbid tube had been boiled for 
only five minutes, while the clear ones had been boiled for ten. On consulting the 
adjacent chamber this possible explanation was blown to the winds, for here the turbid 
tube had been boiled for ten minntes, while its untainted neighbour had been boiled 
for only five. 
Thus, although the more careful repetition of the experiments did not secure every 
tube from infection, the escape of seven out of nine of them entirely destroys the pre- 
sumption of spontaneous life development which the first experiments might seem to 
suggest. 
Wishing to observe more attentively the action of common uncleansed air upon 
boiled fungus-infusions, a tray of 100 tubes was charged with them on the 14th of 
October. Thirty-five tubes were filled with black, thirty-five with yellow, and thirty 
with red-fungus infusion. On the 16th of October every one of the yellow-fungus 
tubes was turbid and covered with a thick, coherent, cobweb-like scum. The surfaces 
of the black-fungus tubes were also sprinkled with spots of white scum. Turbidity was 
the only change observed in the red-fungus tubes. They were wholly free from scum. 
