INTRODUCTION xvii 



a long time be a wide difference of opinion as to the 

 effect which the new knowledge ought to have upon 

 the treatment of disease. The Essays which deal with 

 these subjects set out in clear light the instances 

 where success has been obtained in this respect and 

 they constitute an unchallengeable argument in 

 favour of Pure Science or as I should prefer to call 

 it Experimental Research motivated purely by the 

 desire to increase knowledge. The more intricate 

 the subject-matter the more necessary it is that 

 those engaged in the research should be free to 

 investigate the whole field fully and exhaustively. 

 The game has to be stalked from long distances 

 and often by circuitous routes. It is no longer 

 possible to walk directly up to it. 



Passing from these more obvious examples of 

 Experimental Research one comes to the Essay on 

 the progress of Metallurgy. From this there will 

 be few, except those who are specialists in the 

 question, who will not be surprised as well as 

 delighted by the account of the past growth and 

 the promise of future growth of scientific know- 

 ledge in a subject which one would have thought 

 was specially the domain of the empiricists. 

 Handled as it is, in these Essays, it furnishes in 

 abundance the rich intellectual pleasure of surprise 

 that does not owe its charm to wonder that 

 agreeable product of conscious ignorance. 



The publication of this collection of Essays has, 

 as I have said, been prompted by the fear lest in 



