SPONTANEOUS GENEHATION. 585 
momentary exposure to the boiling temperature," while 
others withstand it for several hours. Most of our ordinary 
seeds are rapidly killed, while Pouchet made known to the 
Paris Academy of Sciences in 1866, that certain seeds, 
which had been transported in fleeces of wool from Brazil, 
germinated after four hours' boiling. The germs of the 
air vary as much among themselves as the seeds of the 
botanist. In some localities the diffused germs are so tender 
that boiling for five minutes, or even less, would be sure to 
destroy them all; in other localities the diffused germs are 
so obstinate, that many hours' boiling would be requisite to 
deprive them of their power of germination. The absence 
or presence of a truss of desiccated hay would produce 
differences as great as those here described. The greatest 
endurance that I have ever observed and I believe it is the 
greatest on record was a case of survival after eight hours' 
boiling. 
As regards their power of resisting heat, the infusorial 
germs of our atmosphere might be classified under the fol- 
lowing and intermediate heads: Killed in five minutes; not 
killed in five minutes but killed in fifteen; not killed in 
fifteen minutes but killed in thirty; not killed in thirty 
minutes but killed in an hour; not killed in an hour but 
killed in two hours; not killed in two but killed in three 
hours; not killed in three but killed in four hours. I have 
had several cases of survival after four and five hours' boil- 
ing, some survivals after six, and one after eight hours' 
boiling. Thus far has experiment actually reached; but 
there is no valid warrant for fixing upon even eight hours 
as the extreme limit of vital resistance. Probably more 
extended researches (though mine have been very extensive) 
would reveal germs more obstinate still. It is also certain 
that we might begin earlier, and find germs which are 
destroyed by a temperature far below that of boiling water. 
In the presence of such facts, to speak of a death-point of 
bacteria and their germs would be unmeaning but of 
this more anon. 
"What present warrant/' it has been asked, "is there 
for supposing that a naked, or almost naked, speck of 
high scientific importance should not have been more thoroughly 
explored. Here the scoundrels who deal in killed seeds might be 
able to add to our knowledge. 
