HEAT UPON LIVING MATTER. 179 
A drop of the fluid containing several of these 
active Monads was placed for about five minutes on 
a glass-slip in a water oven maintained at a tem- 
perature of 140° F. All the movements of the 
Monads ceased from this time, and they never after- 
wards showed any signs of life. 
These experiments are merely two of the most 
remarkable selected from several others in which 
even higher temperatures were originally had re- 
course to in order to free the fluids and flasks 
generally from anything like a trace of living matter. 
Nothing that has yet been alleged by way of objec- 
tion to the admission of ‘spontaneous generation’ as 
an everyday fact, at all affects such experiments as 
these. The shortest way out of the difficulty would 
therefore be to doubt the facts. I can assure the 
reader, however, that they are as true and quite as 
reliable as those other results obtained when work- 
ing with lower temperatures, which, though strongly 
disbelieved in at first, are now generally recognized. 
as trustworthy. And although ‘these now accredited 
results abundantly suffice, in face of our present 
knowledge concerning the limits of vital resistance 
to heat, to establish the strongest probability of the 
occurrence of ‘spontaneous generation,’ yet such ex- 
periments as those which I have now recorded even 
still further confirm this view, since .it becomes in- 
: N 2 
