ft 



PREFACE. * 



The addresses collected in this volume refer to different 

 aspects of one subject — the distinctive character of 

 biological knowledge, and its relation to other depart- 

 ments of knowledge. Ideas on this subject, and on the 

 connection of natural science in general with " human- 

 istic " branches of knowledge, are at present, as it 

 seems to me, changing rapidly, and in a direction which 

 is only very imperfectly realised as yet. The scientific 

 theories which dominated the world during the latter 

 half of last century are undergoing profound modifica- 

 tion, and the estrangement created by them between 

 natural science and other branches of knowledge is 

 tending to disappear. At the same time new lines of 

 advance in natural science are opening out in all direc- 

 tions, and perhaps most strikingly in biology. For this 

 latter reason I have adopted The New Physiology as a 

 title for the book. 



In these addresses the claims of biology to an inde- 

 pendent position among the sciences are strongly main- 

 tained as against the current belief that biology is only 

 applied physics and chemistry. The fourth address 



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