224 THE EVOLUTION OF LIFE 
among them, which, according to ae ought to 
have putrefied. 
“In the present year the same experiment was 
repeated, at the Royal Institution, with the opposite 
result. Most of the infusions became putrid, in 
some instances more rapidly than what were 
intended to be precisely similar infusions exposed to 
the outside air. The experiment was repeated with 
an improved arrangement of the pipette, which had 
fallen under suspicion from the conduct of the 
infusions, but still with the same result. Then the 
incoming air was cleansed not only by the wool- 
filter, but by calcining it by means of red-hot 
platinum, but still with no change in the result. 
Another box was then experimented on at Kew, 
and this time the infusions remained pure with one 
exception, after being kept for a time—not, we think, 
specified—in a temperature varying from 80 to a 
little over 90, a degree of incubating heat not the 
most favourable, but which has very often been 
found sufficient to develop life. The conflicting 
results of these experiments were ingeniously 
accounted for by Professor Tyndall—the failure at 
Kew being ascribed to a pin-hole, and those at the 
Royal Institution to the insufficiency of bent tubes, 
cotton-plugs, and red-hot platinum to keep out or 
kill living germs at Albemarle Street, though they are 
still relied on as sufficient in a purer atmosphere, and 
were found so last year in the Royal Institution itself. 
“The special theory resorted to to explain the 
contrast between the experiments at the Royal 
Institution in the two successive years is that in 1877 
