PREFACE 



THE first edition, issued in 1912, has been out of print since 

 1914, but for various reasons the publication of the second 

 edition has been delayed. During this time many aspects of 

 the subject of internal secretion have undergone material 

 changes. These I hope will find adequate expression in the 

 new version of the book. If I have not been so optimistic 

 and expansive in the treatment of certain topics as other 

 writers on the same subjects, it is because I am convinced 

 that a surer road to sound knowledge lies in the direction of 

 rigid criticism and a reasoned scepticism. 



After much doubt and hesitation I have decided to omit the 

 bibliography. The objections to such a course are obvious, 

 but I found that to review the whole of the literature has 

 become impossible, and to make a selection involves a task so 

 invidious and delicate and at the same time laborious that I 

 have not had the courage to attempt it. The omission of the 

 references to literature will, however, have the advantage of 

 making the book easier to read, and for a large number of 

 students and practitioners will, I hope, not constitute a serious 

 drawback. Investigators who have access to the first edition 

 will find no difficulty in completing a survey of the literature 

 up to the present time. The papers since 1917 are abstracted 

 in Endocrinology, and since 1915 in Physiological Abstracts. 

 Names are still mentioned freely in the text for the reasons that 

 this arrangement involves less re-writing, and that it leaves the 

 responsibi'ity in the hands of the original author on numerous 

 topics in which I have had no opportunity of gaining first- 

 hand information. 



The present edition contains much new matter, but, by 

 re-arrangement and some curtailment of historical and con- 

 troversial sections, it has been possible to avoid increasing the 

 size of the book. The number of illustrations has been 

 increased from 93 to 105. The portions dealing with clinical 



