JV IMIKKITANCK, ! KliTILITY, AND SEX IN PIGEONS. 



The close of Professor Whitman's life, late in 1910, left many problems connected 

 with the present volume quite unfinished. The reader is asked to bear in mind 

 that the author did not consider this work concluded even at the end of the 

 16 years of his study of pigeon hybrids. It was quite important to the purposes of 

 these studies, (1) that the data for longevity and sex of the 600 pigeons that sur- 

 vived him should be learned and added to his records; (2) that certain untested 

 "mutants" be given a breeding-test. Both of these additional tasks were also 

 accepted by the editor and performed by him not well, but with the measure of 

 success that has been possible in connection with much other work and under 

 circumstances not at all times wholly favorable. 



Collectively the seven manuscripts noted above comprise rather less than 100 

 typewritten pages. It thus becomes evident that the reader will meet with the 

 words and work of the editor at very many points and that some method must be 

 found for distinguishing in these pages author from editor. In the main, this has 

 been accomplished by the use of certain postscript letters, 1 but in part also by the 

 use of quotation marks, these latter being most used in the designation of short 

 statements, words, or phrases, transcribed from breeding-records and notes. The 

 postscript letters are placed after longer treatments, complete manuscripts, etc. 

 These take the form of (A 1), (C 7/16), (Sh 14), etc., and in textual materials are 

 placed at the close of the writings of the author. In the tables these letters are 

 uniformly placed at the lower right-hand corner of the table. The tables con- 

 structed from breeding data obtained by the editor bear his initials in the same 

 position in the table. It is believed that the reader will be able to know or to 

 learn the source of all the statements and materials of the volume. He will bear 

 in mind that all of Dr. Whitman's data were obtained prior to December 1910 and 

 that the editor is responsible for all thereafter. 



The postscripts just described have a further and important use. It has been 

 necessary for the editor to make hundreds of summaries of breeding records and 

 to write whole chapters. He hopes and most sincerely believes that he has 

 made a faithful transcript of the original records; but so much hangs upon this 

 matter that he has not felt that he cares to act as the sole or ultimate translator 

 or interpreter of these materials. The postscripts given in these volumes are there- 

 fore fully given and refer to the "shelving or folder classification" given by Dr. 

 Whitman to the original manuscripts. It is planned to file all of these original 

 materials with the Carnegie Institution of Washington, either at its administration 

 building in Washington or at the Station for Experimental Evolution at Cold 

 Spring Harbor. There they will be available to all interested parties; all of the 

 original records, or any specific ones of these, may there be freely and easily 

 consulted. 



In the earlier papers, and also in the one used as an introductory chapter, 

 Whitman was unable to bring forward the remarkable results which were to follow 

 'then only beginning to be observed) bearing on the control of sex in pigeons; but 

 he there (1904) partially outlined a relation between fertility and sex and furnished 



>ns for the following conclusions: (1) that wild forms of unquestioned purity 

 possess a great advantage over domesticated varieties in a study of some of the 



1 This ia a continuation of the plan or method adopted for Volume I of these works. 



