PEEFACE 



This volume is the outcome of a course of nine public lectures 

 delivered at King's College, London, in the Spring term of the 

 Session 1917-18, under the auspices of the Imperial Studies 

 Committee of the University of London. It was felt to be very 

 desirable at this time to bring before the public in as convincing 

 a manner as possible the claims of Zoological Science to recogni- 

 tion on terms of equality with other departments of learning. 

 It would perhaps be better to urge such claims on behalf of 

 the Science of Biology as a whole, for the distinction between 

 zoological and botanical studies is a very arbitrary one, justi- 

 fiable only as a matter of convenience and hardly comparable 

 with the distinction between the sister sciences of Chemistry 

 and Physics, though I imagine that the latter also breaks 

 down when investigations are pushed beyond certain more 

 or less well-recognised limits. There is, moreover, a strong 

 tendency at the present day to insist upon the obvious fact 

 that most, if not all, of those activities of living organisms 

 which are open to scientific investigation are capable of 

 analysis into what may be termed chemical and physical 

 factors, and this insistence, often pushed to unreasonable 

 extremes, has undoubtedly tended to depreciate the inde- 

 pendent value of the biological sciences in many minds. 

 In an ideal educational atmosphere it would be regarded 



