PREFACE vii 



from the originals in the British Museum, Nimrud Gallery, Nos. 

 24, 40, and 2. The portrait of Linnaeus (Plate XV) is from Plate 

 VIll, opp. p. 36, of the collection entitled "Linneportratt vid 

 Uppsala A Universitets Vagnar af Tycho TuUberg, Stockholm, 

 1907." The younger portrait of Camerarius (Plate XIl) is fur- 

 nished by Professor E. Lehmann of the University of Tubingen, 

 from the oil painting in the library of the University. The por- 

 trait of Naudin was kindly obtained by Professor Georges Poir- 

 ault, of the Villa Thuret, Cap d'Antibes, France, and that of 

 Godron by the Doyen of the Faculte des Sciences of the Univer- 

 sity of Nancy. To Professor E. Baur of Berlin, acknowledgments 

 are due for valuable biographical material on Sprengel and Focke, 

 and to Professor Correns for a portrait of Wichura. To Professors 

 De Vries, Correns and von Tschermak are due especial thanks for 

 kindly furnishing full accounts of their individual discoveries of 

 the Mendel papers and the Mendelian theory. In conclusion, with 

 regard to the form of the present book, which may be criticized 

 for its considerable volume of quoted material, it should be said 

 that two ways were open; — simply to digest the material and 

 present it without quotation except in very significant instances ; or 

 to give liberal extracts from the works themselves, in order to sub- 

 serve the purposes of research to those desiring access to the 

 actual corpus of material embodied in the works of the early hy- 

 bridists. In some of the Nageli and Kolreuter material, for ex- 

 ample, the former method was followed, but in general the latter 

 was chosen, even at the risk of creating in part a volume of ex- 

 tracts. It was thought that the real ends of science would be best 

 served in a book of this kind by making it available directly as 

 research material, rather than by sacrificing those ends to the 

 aims of authorship. Hence the resulting rather cumbrous form 

 of the material, which could have been otherwise displayed if the 

 former method had been exclusively followed. It is hoped, how- 

 ever, that the purpose of the book" may be allowed to apologize 

 for its resultant form. 



H. F. Roberts. 



UNIVERSITY OF MANITOBA. 

 AUGUST 2, 1928. 



