HEAT UPON LIVING MATTER. 159 
Is there, then, anything in this fact concerning 
Bacteria and their germs at all at variance with 
what we might have been led to expect, judging 
from our knowledge of the capacity for resisting heat 
shown by other kinds of living matter? Here again 
a negative answer may be unreservedly given. The 
grounds for this opinion must, however, be set forth ; 
and in dealing with this important question I will- 
range what I have to say under the following 
heads :—(1) The results obtained by many other 
investigators working quite independently of one 
another (and in many cases also without distinct 
reference to the Origin of Life question) all go 
to show that different kinds of living matter are 
killed, when heated in the moist state, at or below 
the temperature of 140° F. (2) The only known 
exceptions to this rule, furnished by organisms in hot 
springs, are cases of a special kind differing altogether 
from those with which we are at present concerned : 
though even here it is found that all such organisms 
perish at temperatures short of the boiling point. 
(3) Our knowledge as to the thermal death-point of 
Living Organisms and of units of Living Matter is 
remarkably harmonious, and is in accordance there- 
Recherches sur les Découvertes Microscopiques, et la Génération des 
Corps Organisés,” &c., and not the one from which I have just been 
quoting. 
