BACTERIA AND THEIR GERMS. 87 
ible gemmules, as well as by the known process of 
fission, such invisible particles possess no higher power 
of resisting the destructive influence of heat than the 
parent Bacteria themselves possess.” 
This is, in fact, by far the most satisfactory kind of 
evidence that can be produced concerning the powers 
of resisting heat enjoyed by Bacteria and Vibriones, 
because it also fully meets the hypothesis as to their 
possible multiplication by invisible gemmules possessed 
ofa greater power of resisting heat,and because no mere 
inspection by the microscope of dead Bacteria can en- 
title us positively to affirm that they are dead, even 
though all characteristically vital or ‘true. living’ 
movements may be absent. 
Facts of a very similar nature were mentioned in 
the same work strongly tending to show that Bacteria 
and Vibriones are also killed at the same temperature 
in other fluids, such as infusions of hay or turnip. 
These facts were referred to in the following state- 
ment* :—“ Thus, if on the same slip, though under 
different covering-glasses, specimens of a hay-infusion 
turbid with Bacteria are mounted, (2) without being 
heated, (2) after the fluid has been raised to 122° F. for 
ten minutes, and (c) after the fluid has been heated to 
140° F. for ten minutes, it will be found that in the 
course of a few days the Bacteria under a and 6 have 
notably increased in quantity, whilst those under ¢ do 
* Modes of Origin of Lowest Organisms, 1871, p. 60. 
