162 THE DESTRUCTIVE INFLUENCE OF 
Schultze * and Kiihnet (in part working over the 
same ground) have quite recently fixed the heat 
limits fatal to such organisms at temperatures 
varying between 104° and 113° F. At these tem- 
peratures, indeed, the protoplasm entering into their 
formation, as well as that of the tissue elements of 
higher animals, was not only killed, it became 
coagulated and assumed the condition named by 
Kiihne ‘heat-stiffening.”” Both Max Schultze and 
Kiihne also found that the protoplasm of plant-cells 
with which they experimented (belonging to the 
genera Urtica, Tradescantia, and Vallisneria) was 
similarly killed and altered by a very brief ex- 
posure to a temperature of 1183° F. as a maximum. 
-All accurate new observations, therefore, go to prove 
that different kinds of living matter, whether in the 
form of germ or of developed organism, are killed 
by a brief unaccustomed exposure in the moist 
state to a temperature at or below 140° F. 
(2.) So far I have been referring to the influence 
of heat upon living matter when it is suddenly 
applied to an altogether unaccustomed extent. This 
is the mode of operation with which we are especially 
concerned, as with the view to the interpretation of 
* “Das Protoplasma,” Leipzig, 1863, pp. 33 and 46. 
+ “Untersuch ueber das Protoplasma und die Contractilitat,” 
Leipzig, 1864, pp. 46 and 103. 
