146 THE DESTRUCTIVE INFLUENCE OF 
those used in the different trials, under similar con- 
ditions, alike favourable for germination or develop- 
ment, Spallanzani obtained the following results :— 
Of Frogs’ eggs only an extremely small number 
developed after having been simply raised to the 
temperature of 131° F., whilst not one developed 
which had been heated to 145° or upwards. The 
effects of intermediate temperatures were not tried, 
and consequently the precise death-point was not 
ascertained. The chances are, however, more in 
favour of its being under than over 140° F. Tadpoles 
produced from similar eggs all perished at 111°, and 
the same temperature likewise proved fatal to the 
parent Frogs from which the eggs had been derived, 
as well as to aquatic Salamanders and to some Fish 
with which experiments were made. 
Silk-worms’ eggs, and the eggs of the Elm-moth 
(Papillon de Orme), developed less and less fre- 
quently when successive batches were heated to 
temperatures approaching 144}°. When they were 
actually submitted to this heat all perished, though 
the highest temperature followed by development is 
not recorded. Silk-worms themselves, as well as the 
caterpillars of the Elm-moth, were uniformly killed 
as soon as the water in which they were immersed 
attained 108}°. 
Eggs of the common Blow-fly only developed in 
