AUTHOR'S PREFACE ix 



I have taken into consideration all the recent literature 

 without distinction of language. I am indeed aware that some 

 important papers may have been omitted without intention. 

 There were also great intervals between writing the different 

 parts of the English edition, and some very interesting state- 

 ments from more recent literature could be introduced in 

 Chapters II. and III. only very shortly during the reading of 

 the proofs. But, intentionally, I have omitted some papers 

 which, though much quoted in the current literature on the 

 interna! secretion of the testicle, are devoid of scientific value 

 and are contrary to the real spirit of scientific discussion. 



My personal relations with colleagues working in the same 

 field have been of the greatest use to me. Many of them gave 

 me the opportunity of seeing their patients, their experimental 

 animals and specimens. These colleagues are too numerous to 

 be named here, and I must confine myself to thanking them 

 collectively. Many of them have contributed to the book by 

 kind permission for reproducing their figures. 



The book as it is now could not have been written without 

 the help of those who have collaborated with me in the 

 Institute of Physiology in Dorpat. To Dr. Karl Wagner, 

 now Professor of Histology at the University of Kovno, I 

 am highly indebted for his histological work. The collabora- 

 tion of Dr. B. Ottow, Dr. H. E. V. Voss, Dr. W. Krause was 

 also of great value to me, and likewise that of Dr. E. Blum- 

 Sapas, Miss E. Kropman, Miss S. Brunnow, Miss A. Ibrus, 

 Mr. F. Bormann, Dr. F. Lange, Mr. H. Fuchs>^, Dr. M. Tiitso 

 and Mr. W. Faure. 



Most of the figures which were in the first edition have been 

 replaced by new ones from my own experimental observation. 

 Dr. H. Kull and Mr. S. Vesnjakov did the photographic work, 

 whilst Miss L. Lehbert and Mrs. Lipschiitz made the drawings. 



I have dictated almost the whole EngHsh manuscript to 

 Mrs. Lipschiitz. I thank her here also for the great patience 

 and unselfishness she exhibited and for her linguistic help. 



To Messrs. W. Heffer & Sons my warm thanks are due for the 

 interest they have taken in the publication of the book and 

 for the great care they have shown. 



A. LIPSCHIITZ. 



Institute of Physiology 



OF THE University of Dorpat (Tartu, Estonia). 

 ist July, 1924. 



