PREFACE 



In December and January of 1911-1912 I delivered the Christmas 

 Course of Lectures, " adapted to a Juvenile Auditory," at the 

 Royal Institution of Great Britain, and took as my subject " The 

 Childhood of Animals." The six lectures were not written ; they 

 shaped themselves as the course proceeded, partly in relation to 

 the set of lantern-slides, specimens and hving animals that I was 

 able to bring, and partly in accordance with the advice of my kind 

 and experienced friend Sir James Dewar. This book is not a 

 printed version of the lectures, although it tells the same story in a 

 different fashion. A lecture must be as direct and as little cumbered 

 with detail as may be ; the leaves of a book can be turned back- 

 wards and forwards, and its lines skipped or re-read. I have 

 therefore been able to include many details that I had to omit when 

 I was speaking, and to cover my canvas in a different way. In 

 particular, I am no longer trying to address a juvenile auditory ; 

 I have attempted to avoid the use of terms familiar only to students 

 of zoology, and to refrain from anatomical detail, but at the same 

 time to refrain from the irritating habit of assuming that my readers 

 have no knowledge, no dictionaries and no other books. 



My object has been to bring together observations old and new that 

 seemed to throw a light on the nature of the period in the life-history 

 of animals between birth and maturity, rather than to write a formal 

 treatise on the subject. I have not found it possible, nor have I 

 tried to keep strictly within the logical confines of the title. Where 

 the subject seemed to lead, there I have followed cheerfully, 

 remembering that I am not preparing readers for an examina- 

 tion where no marks wUl be assigned to extraneous matter. 



It has been pleasant to collect the material, pleasanter when it 

 seemed possible to arrange it so as to display a rational interpreta- 

 tion, perhaps most pleasant when the unruly facts refused to 

 conform with theory. Although it may be true, as Lord Morley 

 once wrote, that the universe will never cease to be "a sovereign 

 wonder of superhuman fixedness of law," it is at least a mitigating 



