
THERMAL DEATH-POINTS 51 
out the slower action of cold as compared with hot 
water in moistening dried seeds of other Leguminosz. 
When such seeds had been previously moistened, a 
brief exposure, he says, to “the action of boiling 
water has been found uniformly fatal.” He adds, 
‘All the organisms in which we are interested at 
present, however, have no such protection. These 
are mere specks or masses of protoplasm, which are 
either naked or provided only with thin coverings” 
—reference being here made to germs of Bacteria 
and Fungi, with which we shall be concerned in ex- 
periments concerning life-origination. | 
Thus, not a single living thing, egg, or seed could 
be shown by Spallanzani to be capable of resisting, 
when in the moist state, an exposure to boiling 
water for a single moment; and in order not to 
accept the conclusions of Needham he was obliged 
to fall back upon two assumptions: (a) that the 
unknown germs, whose existence he postulated, were 
of the nature of seeds rather than eggs, being sup- 
posed to be capable of undergoing desiccation with 
impunity, and thus possessing a greater power of 
resisting heat; and (é) that although no seeds could 
be shown to be able to resist the influence of boiling 
water, these unknown seed-like germs mzg/¢ be able 
to do so. 
But Burdach exhibited much sagacity some years 
later when in reference to unknown germs, postul- 
ated also in his time, he said: ‘ Les dit-on trop 
petits pour étre apercus, c'est avouer qu'on ne peut 
rien savoir de leur existence. . . . Croire que partout 
ou l’on rencontre des infusoires, ils ont été précédés 
