586 FRAGMENTS 
protoplasm can withstand four, six, or eight hours' boil- 
ing? " Regarding naked specks of protoplasm I make no 
assertion. I know nothing about them, save as the crea- 
tures of fancy. Bnt I do affirm, not as a " supposition," nor 
an "assumption/ 7 nor a "probable guess," nor as "a wild 
hypothesis," but as a matter of the most undoubted fact, 
that the spores of the hay bacillus, when thoroughly desic- 
cated by age, have withstood the ordeal mentioned. And 
I further affirm that these obdurate germs, under the 
guidance of the knowledge that they are germs, can be 
destroyed by five minutes' boiling, or even less. This 
needs explanation. The finished bacterium perishes at a 
temperature far below that of boiling water, and it is fair 
to assume that the nearer the germ is to its final sensitive 
condition the more readily will it succumb to heat. Seeds 
soften before and during germination. This premised, the 
simple description of the following process will suffice to 
make its meaning understood. 
An infusion infected with the most powerfully resisteut 
germs, but otherwise protected against the floating matters 
of the air, is gradually raised to its boiling-point. Such 
germs as have reached the soft and plastic state immediately 
preceding their development into bacteria are thus 
destroyed. The infusion is then put aside in a warm room 
for ten or twelve hours. If for twenty-four, we might have 
the liquid charged with well-developed bacteria. To antici- 
pate this, at the end of ten or twelve hours we raise the in- 
fusion a second time to the boiling temperature, which, as 
before, destroys all germs then approaching their point of 
final development. The infusion is again put aside for ten 
or twelve hours, and the process of heating is repeated. 
We thus kill the germs in the order of their resistance, 
and finally kill the last of them. No infusion can with- 
stand this process if it be repeated a sufficient number of 
times. Artichoke, cucumber, and turnip infusions, which 
had proved specially obstinate when infected with the 
germs of desiccated hay, were completely broken down by 
this method of discontinuous heating, three minutes being 
found sufficient to accomplish what three hundred minutes' 
continuous boiling failed to accomplish. I applied the 
method, moreover, to infusions of various kinds of hay, in- 
cluding those most tenacious of life. Not one of them bore 
the ordeal. These results were clearly foreseen before they 
