84 THE EVOLUTION OF LIFE 
The inoculated mixture was then heated on a 
sand bath till a thermometer in the fluid (passed 
through the cock of the receiver) stood at 80° C. 
(176° F.), and at this temperature it was maintained 
for 5/ only. 
With this heated inoculated nourishing fluid 12 
purified flasks, plugged with carbolised cotton-wool, 
were most carefully charged, with all precautions. 
The plugs being replaced, each flask was put into 
the incubator at 120 F., and there allowed to 
remain at this temperature. The results were as 
follows :— 
One of the flasks was accidentally broken ; but of 
the remaining 11 all but three were lighter coloured 
and distinctly turbid from multiplication of Bacilli in 
24 hours; by 36 hours two of the others were 
turbid ; but up to the end of the fifth day the fluid 
in the one remaining flask was still quite clear. 
Thus out of 11 trials, on ten occasions it was found 
that these desiccated Bacillus spores were able to 
resist a temperature from r1o°-20° F. higher than 
the organisms from which they had been derived. 
What their precise death-point would be still 
remains rather uncertain, though it seems clear from 
the other 63 trials that there is a very remote 
chance for any of them being able to resist the 
destructive influence of 212° F. for 20’. This con- 
clusion will be found to be one of considerable 
importance in reference to the interpretation of 
other experiments to be recorded in this volume. 
The only other point concerning the question of 

