PREFACE 



IN writing this Introduction to Biology, I have used, to 

 a large extent, the notes of lectures delivered by my 

 first teacher in Zoology, Professor J. Arthur Thomson. 

 No doubt he will find many phrases and expressions 

 and many lines of thought which are quite familiar ; 

 for using these I make no apology, for they st^m to me 

 to give the very essence of the subject briefly and very 

 aptly. I must also express my debt to the writings 

 of Professor Harvey Gibson, which I have found very 

 helpful and illuminating. 



It is quite possible that I may have omitted much that 

 others would have put in, and that I have written more 

 fully on some points which others would have curtailed ; 

 but be that as it may, I only hope that this Introduction 

 will interest and be of some slight service to those who 

 are beginning the study of Biology. 



For all errors of fact and exposition I alone am re- 

 sponsible, and if I have interpreted any views or theories 

 wrongly, I tender my sincere apologies. 



W. D. H. 



BRISTOL, 1913. 



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