THERMAL DEATH-POINTS 55 

relatively violent, and therefore liable to destroy 
life by its suddenness.” 
Hence it is, as we have seen from the experiments 
of Spallanzani, and shall now see from other more 
recent investigations of a similar nature, that a 
temperature considerably lower than that of the 
hot springs above mentioned suffices to kill almost 
all living matter not previously inured to the in- 
fluence of heat. ; 
Thus Pouchet! found that all kinds of Ciliated 
Infusoria experimented with were killed at 131° F.; 
and while confirming this observation, I have 
found that a brief exposure to the same temperature 
always sufficed to kill Amoebz, Monads, Euglene, 
Desmids, Rotifers, Nematoids, and other minute > 
aquatic organisms. I did not try to ascertain 
what was the lowest temperature which would prove 
fatal to these organisms, though many of the same 
kinds of living things were found by Spallanzani 
to perish at temperatures from 107'-113°; while 
Max Schultze and Kiihne (in part working over the 
same ground) subsequently fixed the heat-limits 
fatal to such organisms at temperatures varying be- 
tween 104° and 113° F. The protoplasm entering 
into the formation of the tissue elements of higher 
animals was not only killed at a’ point below the 
higher of the two just named, but it became coagu- 
lated also, 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 ex- 
1 “ Nouvelles Expériences,” etc., 1864, p. 38. 
