120 THE DEATH-POINT OF BACTERIA 
II. To the second subclass belong fluids which, 
after exposure toa temperature of 212°F. or higher, 
may be kept clear or apparently unaltered so long as 
they are shut off from contact with unheated atmo- 
spheric or other organic particles, but which do under- 
go putrefaction, or more or less marked fermentation, 
soon after they are brought into contact even with 
mere not-living organic matter. 
The experiments recorded in this communication 
have most conclusively proved the efficacy of not- 
living organic matter as a ferment or inciter of change 
in previously barren fluids. And combining the know- 
ledge derived from these experiments with that which 
we pow possess concerning the absence of living 
Bacteria, Vibriones, and their germs in the air, to- 
gether with the known prevalence of minute organic 
particles and fragments of various kinds, the explana- 
tion of M. Pasteur’s celebrated experiments in which 
established that living organisms could appear in saline solutions free 
from traces of organic impurity. Mr. Hartley did attempt to work with 
approximately pure saline solutions, and in other respects also the con- 
ditions of his experiments differed so much from mine, that the results 
which he obtained could not possibly be considered to disprove what I 
had previously stated. Some of his flasks were heated to 180° C., a 
temperature about which I had said nothing; and whilst his organic 
infusions were too weak, some of his saline solutions were too concen- 
trated, though the strengths of others were not given at all. Fluids 
were also employed (such as urine, heated to 130° C.) which I had not 
made use of, and which I should not have thought of experiment- 
ing with. 
