objERVation and experiment 81 



As an illustration of the blunders referred to I may cite the 

 profound reluctance even of eminent men of science to accept 

 the plainest teachings of observation with respect to geological 

 time up to the middle of the century just passed. Not until 

 Lyell the great champion of uniformitarianism, as opposed to 

 catastrophism, had published his "Principles" (1830) did 

 scientific opinion show a tendency to accept the fact of the 

 hoary age of the earth everywhere attested by the rocks in her 

 crust. 



And what a storm of opposition and condemnation, amount- 

 ing almost in some cases to social ostracism, was visited by the 

 very " salt of the earth " against those who ventured during the 

 sixties and the seventies of the last century to consider favorably 

 the arguments of the " Origin of Species " ! All this has about 

 it the freshness, and possibly the pain and the humor, of per- 

 sonal recollection for those of us who are old enough to have 

 lived in two epochs. That a mistake of this sort could have 

 been made thirty or forty years ago seems strange enough in 

 these peaceful times of ours. But while we may properly let 

 the recollection of the storm and stress of this earlier period 

 fade away, the moral of the conflict should be held up as a per- 

 manent warning to scientific as well as unscientific men ; for no 

 episode in the previous experience of the race demonstrates so 

 clearly the sources of knowledge and the methods of attain- 

 ing it. 



As a final illustration of the validity of my thesis I would in- 

 vite your attention to one of the most instructive and beneficent 

 of the many brilliant biological researches of recent times. No 

 one who has suffered from repeated attacks of intermittent fever 

 and has survived the ravages of the materia medica, can fail to 

 take a lively interest in the wonderful progress made during the 

 last twenty years towards a definite knowledge of the natural 

 history of that disease. Nor can any one interested in the 

 general aspect of science fail to see in the investigations leading 

 up to this progress some of the finest examples of the scientific 

 method. 



It would appear that malarial fever has been one of the com- 



