BACTERIA AND THEIR GERMS. 95 
putrefaction invariably occurs within'two days; whilst, 
on the contrary, whenever they are subjected to a 
temperature of 158° F. (7o°C.) putrefaction does not 
occur. To what can this difference be due, except to 
the fact that the previously living organisms, which, 
when living, always excite putrefaction, have been 
killed by the temperature of 158°F.? It would be of 
no avail to suppose that the absence -of putrefaction 
in these latter cases is due to the fact that a heat of 
158° F., instead of killing the organisms and their 
germs, merely annuls their powers of reproduction, 
because in the other series of experiments (with which 
these have to be compared), where similar fluids are 
exposed to ordinary or purified air, or are shut off 
from the influence of air altogether, the most active 
putrefaction and multiplication of organisms takes 
place in two, three, or four days, in spite of the much 
more potent heat of 212° F. to which any pre-existing 
germs or organisms must have been subjected. The 
supposition, therefore, that the Bacterza, Vibriones, and 
their germs were not killed in our inoculation experi- 
ments at the temperature of 158° F., but were merely 
deprived of their powers of reproduction, would be no 
gain to those who desire to stave off the admission 
that Bacteria and Vibriones can be proved to arise de 
novo in certain cases, Let us assume this (which is 
indisputably proved by these inoculation experi- 
