PERSISTENCE OE PUTREFACTIVE AND INFECTIVE ORGANISMS. 
201 
broken off in the midst of a spirit-lamp flame. It is known that gunpowder can be 
dropped through such a flame without ignition ; and in a few rare instances the infusions 
which had their first supply of air thus passed through a flame showed subsequent signs 
of life. In such cases the germinal matter had been sucked so rapidly through the 
flame that it escaped destruction ; but in the vast majority of instances the sterilized 
infusions remained sterile. 
Mechanical arrangements were also made for the breaking off of the sealed ends in a 
receiver filled with filtered air. But it is by no means easy to perfectly cleanse from 
infectious matter the instruments used in such experiments, though with sufficient prac- 
tice this might certainly be done. The consequence was that some of the flasks opened 
in filtered air yielded subsequently. The following is an illustrative case : — On the 3rd 
of January ten flasks were charged with cucumber-, turnip-, artichoke-, and melon- 
infusions. They were boiled for the usual time, sealed during ebullition, and exposed 
afterwards to a warm temperature. Their sealed ends were then broken off by a 
mechanical contrivance placed in a receiver containing filtered air. The two artichoke- 
flasks remained permanently barren afterwards. Of the two melon-flasks, one remained 
barren and the other developed life. Of the two cucumber-flasks, one became turbid, 
the other remained clear. Of the four turnip-flasks, two became turbid and two 
remained clear. Out of the ten flasks, therefore, all freely connected with the external 
air, six remained permanently barren. By further practice barrenness in almost every 
instance has been secured. The conclusion, I think, is obvious. It is not the heat 
alone that destroys these germs, for fifty times the amount of heat will not accomplish 
this when oxygen in due quantity is present : the heat must be aided by the withdrawal 
of the oxygen. 
§ 26. Mortality of Germs through excess of Oxygen. 
The foregoing remarks lead naturally to a brief reference to the important experi- 
ments of M. Paul Beet* on the toxic influence of compressed oxygen. From the 
imperfect account of these experiments which first reached me, I inferred that the 
germs of putrefaction had been destroyed by mere mechanical pressure, and more 
than a year and a half ago I placed turnip-infusions in strong iron bottles, and sub- 
jected them for several days to an air-pressure of twenty-three atmospheres. When 
taken from the bottles the infusions were found one and all swarming with life. Last 
October I made a series of similar experiments with infusions of hay and turnip, sub- 
jecting them for several days to an air-pressure of twenty-seven atmospheres. When 
taken from their iron bottles the infusions were found one and all teeming with 
Bacteria. 
I then resorted to pure oxygen, and found the same to be true of my infusions that 
M. Paul Beet had found true of his flesh, moist bread, boiled starch, strawberries, 
cherries, wine, and urine. Pressures varying from twenty-seven atmospheres to ten 
* Comptes Rendus, vol. lxxx. p. 1579. 
