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THERMAL DEATH-POINTS 45 
of living things. This simple issue was therefore 
fully realised by Spallanzani, and, acting in accord- 
ance with the most obvious of scientific principles, he 
carefully sought for fresh evidence, by means of well- 
directed experiments, in order to guide him towards 
a conclusion as to whether germs of living things 
could or could not have resisted the action of boiling 
water for more than half-an-hour. 
His results were embodied in a work, translated 
by Jean Senebier under the title ‘‘Opuscles de 
Physique Animale et Végétale” (Geneva, 1767), to 
which reference may most conveniently be made. 
Spallanzani approached the question in the follow- 
ing manner: “Can one,” he says, “find any proof 
sufficient to banish, or, at all events, to diminish 
one’s natural repugnance to admit that the germs of 
animalcules of the lowest order have the power of 
resisting the action of boiling water? In reasoning 
from the germs or eggs of animals with which we 
are acquainted, would it be difficult for us to imagine 
animalcules having this peculiarity? It is true that 
we are not acquainted with any eggs endowed with 
such properties. I have already considered this 
subject in the ninth chapter of my Dissertation. | 
there show how several kinds of eggs of insects— 
not to speak of eggs of birds—perish under a heat 
less than that of boiling water. I have shown also 
that the seeds of plants are destroyed when they are 
exposed to the heat of boiling water, and that even 
those whose coat is of the hardest description are not 
thereby spared.” 
But, he goes on to say, as he had only been able 
