
THERMAL DEATH-POINTS 73 
nature of the fluid to impede the development of the 
organisms. 
Having ascertained that hay-bacilli also grew and 
multiplied with about equal readiness in such acid 
urine, I subsequently executed a third series of 
experiments, in which the inoculating material was 
similar to that of A in the fact that it swarmed with 
Bacillus spores, only it was composed of hay-infusion 
instead of urine, in which the organisms had gone 
on to spore-formation. The results were, however, 
in no way different. Out of twenty-four trials with 
this fluid as the inoculating medium, fermentation 
did not take place in a single instance, the inoculated 
fluids having been boiled as before for ten minutes. 
It seems perfectly clear, therefore, that the spores 
of Bacilli when in the moist state are all killed by 
ancexposure to: 2%2° PF, (100 C.) for ten minutes. 
Probably they would have been killed at some point 
intermediate between this and 158° F.—the latter 
being the temperature which, as we have seen, kills 
all kinds of Bacteria except a very few of the 
thermophilic forms. What the exact death-point of 
these spores is, however, I did not ascertain at the 
time ; and, so far as I know, it has never since been 
done. 
In reference to the spores of Fungi, also, de 
Bary’? mentions that in their dry state 130° C. has 
been necessary for their destruction, though he 
adds, “the death-point of the spores of Fungi is 
often much lower than this in water or watery 
vapour, and it has not been shown that any can 
'“ The Structure and Functions of Bacteria,” Transln., 1900, p. 76. 
