82 THE EVOLUTION OF LIFE 
and the fluid in each was boiled for about one 
minute, when the neck of the retort was sealed 
during ebullition. Subsequently the retorts were 
inverted, and immersed in a can of boiling water 
for different periods. 
Two were boiled in the can for 10’, within half 
an hour after the wetting of the spore material. 
Two were boiled for 20’, within one hour after 
the wetting of the spore material. 
Two others were boiled for 30’, within one and a 
half hours after the wetting of the spore material. 
One of the retorts heated for 20’ was accidentally 
broken, but the other five were placed in the in- 
cubator at 120° F., and there left for five days, all 
the fluids having remained clear and unchanged. 
Another set of experiments was made with a 
slight variation in method. To a stock of sterilised 
urine in a Lister's receiver, a quantity of the spore 
liquid (after only a brief preliminary soaking) was 
added in the proportion of two minims to the ounce 
as before. From the inoculated fluid in the re- 
ceiver, 23 small flasks plugged with carbolised 
cotton-wool were charged, and the fluid in each of 
the plugged flasks was gently boiled over the flame 
for 12’. One of these flasks was accidentally 
broken. A control experiment was also prepared, 
in which the urine was boiled alone, and when it 
had become somewhat cool it was inoculated with 
two minims of the unheated spore liquid. All were 
then placed in the incubator at 120° F., with the 
following results :— 
The fluid in the control flask was found in 24 

