PREFACE 



>Tr*HE aim of this book of short studies is to 

 * interest thoughtful readers in the multitudi- 

 nous problems of animal life as they present them- 

 selves to the modern biologist. Some of them deal 

 with old problems which have reasserted themselves 

 in new guise ; others deal with new problems which 

 recent research has brought into prominence. Most 

 of them are confessedly appreciations of, and re- 

 flections on, the investigations of other naturalists, 

 and most of them were, to begin with, " lectures " 

 to senior students of Natural History in this Uni- 

 versity. It need hardly be said that the subjects 

 chosen are only representative, and that the light 

 thrown on them tends rather to an appreciation 

 than to a solution of the problems involved. Nature 

 so often tells us one secret in terms of another. 

 The first ten studies deal with individual animals; 

 the next six have to do with the web of life; the 

 ten that follow raise problems of development and 

 behavior two subjects more intimately related 

 than appears at first sight; the remaining fourteen 



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