102 JOURNAL OF SCIENCE 
BACTERIA.* 
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(Continued from p. 54.) 
A beam from the electric light passed through the two side 
windows, at first reveals “motes” or atmospheric dust inside the 
chamber as well as outside, but after a few days the beam shows 
an entire absence of motes inside the chamber. The dust has, 
in fact, all fallen on to the bottom and sides of the chamber, 
where it has been caught by the sticky glycerine, and any living 
germs in it killed. When the dust has thoroughly subsided, the 
tubes are filled by means of the funnel, which is afterwards 
plugged with cotton wool moistened with glycerine. A vessel 
filled with brine is now brought under the apparatus, and raised 
until the lower ends of all the tubes are immersed in the brine, 
which is then thoroughly boiled for some time. The ends of 
the bent tubes are then temporarily plugged with cotton wool, 
the brine bath removed, and the fluids allowed to cool. Finally 
the wool plugs are removed from the bent tubes, so as to place 
the fluids in free communication with the air. In this case any 
germs carried into the bent tubes by currents of air are certain 
to be caught in one or other of the bends and killed by the gly- 
cerine, since it is practically impossible that any particle should 
take the zig-zag course necessary for entrance into the chamber 
without ever touching the sides of the tube. 
Except in cases which I shall discuss hereafter, these experi- 
ments, if carefully prepared, all give the same result—putrefac- 
tion does not occur, the fluid remaining clear and sweet for any 
length of time. Pasteur and Tyndall made experiments of the 
sort literally by hundreds. I knew of one flask plugged with 
cotton wool which remained unaltered for fully seven years in 
London, and was still unaltered when I left. In the Dunedin 
Museum I have a Tyndall’s chamber containing infusions of hay, 
turnip, mutton, and fish, and sealed tubes of mutton and turnip 
infusion which were prepared in May, 1882, and none of which 
shew the slightest sign of putrefaction. 
I mentioned incidentally that there was an exception to the — 
rule that in carefully-conducted experiments of this sort putre- 
faction did not occur. Professor Tyndall found, at one stage of 
his experiments, that infusions made of o/d hay always putrefied, 
however long they were boiled, and whatever care was taken to 
exclude germs. 
The way Tyndall grappled with this apparently anomalous 
result gives a very good practical instance of scientific method. 
Many observers would have immediately jumped to the conclu- 
sion that at last there was clear proof of spontaneous generation. — 
Tyndall, on the other hand, argued something like this :—Thou- 
*A lecture delivered at the Oamaru Atheneum and Mechanics’ Institute, on — 
30th January, 1884, by Prof, T, Jeffery Parker, 
