INTRODUCTION 5 



The newer and more extensive reviews are those of 

 du Buy and Nuernbergk (1932, 1934, 1935), Erxleben (1935), 

 von Guttenberg (1932, 1933, 1934, 1935, 1936), Heyn 

 (1936), Jost (1935), Kogl (1935, 1935a, 1936), Haagen Smit 

 (1935), Stiles (1935), Thimann (1935, 19366), Went i 

 (19356, 1936a), and F. A. F. C. Went ^ (1934, 1935). 



The most complete account which has appeared up to now 

 is that of Boysen Jensen (1935, translated and extended by 

 Avery and Burkholder, 1936). We do not feel, however, that 

 Boysen Jensen's publication makes our book superfluous, for 

 several reasons. In the first place, it does not attempt to do 

 more than review the past work, while in this book our aim 

 is rather to analyze and integrate the material. In the second 

 place, its scope is restricted largely to the role of hormones 

 in growth and tropisms, while, as was stated above, the field 

 has recently developed in quite different directions, which 

 necessitates a revision and broadening of our ideas. Lastly, 

 it appears from book reviews (Soding, 19356; Umrath, 1935) 

 that one of the principal impressions which the book has 

 made is in regard to the question of priority in the discovery 

 of the auxins. We feel that the gradual unfolding of the 

 current conceptions and the cooperation of different workers 

 has made it impossible to credit any one person with such a 

 discovery, and it is to be hoped that the reader of this book 

 will gain the impression of a steady and collective advance 

 rather than of individual contributions. 



> References to Went (without initials) refer to F. W. Went, the papers of 

 F. A. F. C. Went being cited with initials. 



