BACTERIA AND THEIR GERMS. 93 
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 in- 
oculated organic infusions remained clear, as had 
been the case with the saline solutions in my previous 
experiments when heated to 140° F. There remains, 
therefore, an intermediate heat zone (ranging from a 
little below 140° to a little below 158° F.) after an 
exposure to which the inoculated organic infusions 
are apt to become more slowly turbid, although in- 
oculated saline solutions raised to the same tempera- 
tures invariably remain unaltered. The full explana- 
tion of these apparent anomalies I propose to make 
the subject of a future communication to the Royal 
Society; meanwhile we may quite safely conclude 
that Bacteria, Vibriones, and their supposed germs are 
either actually killed or else completely deprived of 
their powers of multiplication after a brief exposure 
to the temperature of 158° F, (70° C). 
This evidence now in our possession as to the limits 
of ‘vital resistance’ to heat displayed by Bacteria, 
Vibriones, and their supposed germs in neutral saline 
solutions, and in neutral or acid organic infusions, is 
* In the experiments already referred to, p. 85. 
