x PREFACE 



body become manifest. Since glandular disorders 

 are among the commonest causes of disease, ranging 

 from slight mental or physical derangement to com- 

 plete mental or physical breakdown, a general sur- 

 vey of the subject, told in popular but not sensa- 

 tional language, faithfully recording what has been 

 accomplished, should prove of interest. There is a 

 crying need, in the opinion of the author, of simple, 

 yet clear and clean-cut statements of scientific work 

 to which the layman can refer. The half-baked 

 knowledge that he often gets at present is worse 

 than no knowledge at all. 



Not the least interesting part of this fascinating 

 field of research is the evidence we possess that the 

 activities of these glands are dependent upon rela- 

 tively simple chemical substances contained in them, 

 to which the name "hormones" or "chemical mes- 

 sengers" has been given. Without in any way at- 

 tempting to exaggerate their importance, we may say 

 of these hormones that they are as indispensable to 

 the life process as are vitamines, a subject treated 

 by the author in an earlier volume. 



I am indebted in various ways to the following: 

 Professor W. B. Cannon (Harvard) ; Professor W. 

 J. Gies (Columbia); Dr. Max Kahn (Columbia); 

 Dr. E. C. Kendall (Mayo Clinic, Rochester, Minn.) ; 

 Dr. E. G. Miller, Jr. (Columbia) ; Mr. A. L. Robert; 

 Mr. Thomas Spector; Professor G. N. Stewart 



