54 THE EVOLUTION OF LIFE 
we have quoted give satisfactory proof that different 
kinds of plants may live in waters of various 
temperatures as high as 168° F., as observed by | 
Dr Hooker in Sorujkund; 174°, as observed by 
Captain Strachey, in Thibet; 185°, as observed by 
Humboldt in La Trinchéra; 199°, as observed by 
Dr Brewer in California ; and 208°, as observed by 
Decloizeauz in Iceland.” 
Having no grounds for criticising these observa- 
tions, we are bound to look upon them, provisionally, 
as correct, and taken with all due care—though it is 
oniy fair to add that Max Schultze! and F. Cohn 
appear to be not altogether satisfied with some 
statements of the same kind. Such instances, if 
thoroughly accurate, may perhaps be taken as 
examples of the highest temperature that it is 
possible for living matter to endure, day after day 
and week after week, even where it has been 
inured to the influence of heat in the most gradual 
manner. The real point cf view from which such 
facts should be regarded was pointed out by Pro- 
fessor Wyman when he said: ‘‘ Having become 
adapted through a long series of years to their 
surroundings, such organisms may be supposed to 
live under circumstances the most favourable possible 
for sustaining life at a high temperature. It is a 
well-known physiological fact, that living organisms 
may be slowly transferred to new and widely different 
conditions without injury ; but if the same change is 
suddenly made they perish. In the experiments 
made in our laboratories, the change of conditions is 
1 “Das Protoplasma,” Leipzig, 1863, p. 67. 

