64 THE EVOLUTION OF LIFE 
became easy. Full details as to the method adopted 
and the results obtained are given in The Proceedings . 
of the Royal Soczety (March 1873, pp. 226-32). 
It is only necessary to say here that turnip and 
hay infusions were boiled for ten minutes, and after 
they had become cool they were inoculated with a 
hay infusion swarming with Bacteria in the propor- 
tion of one drop to each ounce of the fluid. This 
stock liquid was then poured into a purified beaker 
placed upon a sand-bath, and its contained fluid (in 
which a thermometer was immersed) was gradually 
raised to the required temperature, at which it was 
maintained for five minutes, by alternately raising the 
beaker from and replacing it on the sand-bath. 
Purified one-ounce bottles and corks were then used, 
the former being filled to the brim, and the corks 
tightly pressed home. The bottles, filled with 
inoculated infusions heated to various degrees, were 
subsequently maintained at a temperature ranging 
from 65° to 75. F. 
The results of the 102 experiments that were 
then made with hay and neutral acid turnip infusions 
were embodied in two tables (doc. cz¢., p. 230), an in- 
spection of which led to the following conclusions :— 
‘The experimental results above tabulated seem 
naturally divisible into three groups. ‘Thus, when 
heated only to 131° F., all the infusions became 
turbid within two days, just as the inoculated saline 
solutions had done. Heated to 158° F., all the 
inoculated organic infusions remained clear, as had 
been the case with the saline solutions, in my 
previous experiments, when heated to 140 F. 

