PREFACE 



It is common for an author to explain in his preface that he has 

 written his book for some particular class of persons. Critics sometimes 

 wonder artlessly why a book has been written at all. I can be quite 

 clear about all this: I wrote the book for myself 



I have no recollection of a time when I was not interested in zoology 

 in general and the Amphibia in particular. Choosing the commonest 

 in my neighbourhood, I have spent about thirty years studying the 

 Common Frog and its tadpoles. Most of this work was ecological, 

 but there were excursions into behaviour, biochemistry, parasitology, 

 anatomy and physiology, for the life of an animal requires for its 

 illumination any scientific technique that can be brought to bear. I 

 did this to please myself. Having reached a point when one of the 

 major problems had received a solution, in the partial and temporary 

 way that scientific problems are usually solved, I decided to put into 

 effect a long-considered plan, and write a book to please myself If 

 anyone looks over my shoulder at what I have written, the publishers 

 and I hope that he will be pleased, too. 



It will naturally be found that some parts of the book are much 

 more difficult than others. It is fortunate that the lives of animals bear 

 so many resemblances to our own that everyday language can often 

 be used, and is indeed often better than special technical terms, which 

 in ecology seem to change their meaning. The book, hov^^ver, is not 

 artificially simplified, and I have dealt with some necessarily compU- 

 cated aspects of the subject by explaining as I go along, or by including 

 the more detailed matter in the final chapter on methods, or in 

 Appendixes. The narrative is continuous: it is not a textbook to be 

 studied, but rather a story to be read. 



Most of the matter has already been published, either by myself or 

 by others, in various scientific journals, but some is here presented for 

 the first time. For example, the observations in Chapter i on the 

 formation of the jelly envelope of the egg, although very incomplete, 

 are new, and so is a large part of Chapter 8, in which the relation 

 between the date of spawning and the weather is investigated. In tins 

 chapter and in Chapter lo, will be found what I believe to be the first 

 account of methods of ecological investigation of voluminous data 



