

THERMAL DEATH-POINTS 49 
killed by an immersion for only ten minutes in 
water of 45° or 46° C. [113° or 114°8° F.].” 
Thus Spallanzani’s researches taught him three 
things: (1) that eggs can withstand a decidedly 
higher degree of heat than that proving fatal to 
their parents; (2), that an analogous difference 
exists between seeds and plants, in respect to their 
capacity of withstanding the action of heat; and 
(3), that seeds and plants can resist higher grades 
of heat than eggs and animals respectively. 
In seeking for an explanation of these results, he 
quickly dismissed—as Burdach did rather later— 
the utterly improbable notion that the smallness of 
the germ or egg can act as its safeguard, by render- 
ing it less amenable to the influence of heat. He 
inclined rather to the view that the increased power 
of resistance possessed by seeds and eggs, as com- 
pared with the organisms from which they proceed, 
was due to the simplicity of the embryo within the 
seed or the egg ; and he asks whether the fact of this 
life being ‘‘so small and so feeble”’—being ‘a life 
which deserves so little the name of life ”—may not 
be the reason that seeds and eggs are able to resist 
heat so much better than developed organisms. He 
adduces reasons tending to support this view ; and 
thinks the same kind of explanation is applicable to 
the greater tolerance of the injurious effects of heat 
upon seeds and plants, as compared with that shown 
by eggs and animals. 
The greater tenacity of life of seeds is only in part 
due to the fact that the outer coats of most seeds 
are much harder than those of eggs. Thus the 
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