

PREFACE 



IN the present work it is intended to present, in some fulness and 

 detail, all the significant results obtained in the field of plant- 

 hybridization, down to the discovery of Mendel's papers in 

 1900. The work of the early hybridists has never hitherto been 

 adequately analyzed and discussed as a whole. Attention has been 

 so concentrated upon Mendelian problems, that the contributions 

 of the precursors of the present scientific period in genetics have 

 been mostly overlooked, and not infrequently underestimated. To 

 bring these contributions out of oblivion, to present them in se- 

 quence, and in their relation to one another and to our present 

 knowledge, is the aim and purpose of the writer. In assembling 

 this material, the work of individual breeders upon the improve- 

 ment of some single species of plant, usually conducted entirely 

 from an empirical or purely practical standpoint, has generally 

 been omitted, those investigators only being included who have 

 contributed in some essential manner to the theory of fertilization 

 and hybridization in plants, and who have thereby laid a founda- 

 tion for the synthetic development of genetic theory. If Mendel's 

 papers themselves have been analyzed with unusual minuteness 

 and detail, it is because the writer feels that such a thoroughgoing 

 analysis is generally omitted in the current text-books on heredity, 

 and that in a work of this sort, intended to be historical rather 

 than genetic in character and also intended to be useful for refer- 

 ence purposes and to the general reader, it should be his duty to 

 make as complete an exposition as possible of each investigator's 

 contribution. It should be therefore^stated that in the presentation 

 of the Mendel material the details have been given with the same 

 thoroughness and simplicity as though the paper were being re- 

 viewed for the first time. It was thought by this means to be more 

 nearly possible to bring Mendel's actual work into its deserved 

 relief, too often obscured by brief statement. This will also suffice 

 to account for the simple and elementary re-statement of the 



