Now this experimenter says that he took these monads and heated them to a temperature of about 140 deg.  F., and they were all absolutely killed.  This is accurately our experience.  But he says these monads arose in a closed flask, the fluid of which had been heated up to 270 deg.  F. Therefore, since they are killed at 140 deg.  F., and arose in a fluid after being heated to 270 deg.  F., they must have arisen de novo! But the truth is that this is the monad whose spore only loses its power to germinate at a temperature (in fluid) of 290 deg., that is to say, 20 deg.  F. higher than the heat to which, in this experiment, they had been subjected.  And therefore the facts compel the deduction that these monads in the cress arose, not by a change of dead matter into living, but that they germinated naturally from the parental spore which the heat employed had been incompetent to injure.  Then we conclude with a definite issue, viz., by experiment it is established that living forms do not now arise in dead matter.  And by study of the forms themselves it is proved that, like all the more complex forms above them, they arise in parental products.  The law is as ever, only that which is living can give origin to that which lives.

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