sei-ve the ornitliologist and the research worker in bird wikliile, in that rep- 

 resentative studies have been made on species other than the domestic chicken; 

 and where cells of wild species differed from those of chickens, they have 

 been illustrated and described. 



Innumerable names have been applied to the different blood cells and 

 their developmental stages. Many of these are synonyms, many carry the 

 implication of adherence to a particular theory of hematopoiesis, and many 

 are the products of the clinical laboratory and of the anatomical labora- 

 tory. Whether all workers agree on the suitability of the names that, in 

 this book, have l)een attached to the drawings and are summarized in table 

 2 is not important but it is important that the mental image of a particular 

 cell should be the same in the minds of all who discuss it. and to this 

 end an atlas functions as liaison among many persons. 



No attempt is made to champion any theory of hematopoiesis; the total 

 effort has gone into recording what was seen and putting the cells in serial 

 order whenever possijjle. In some cases it has been impossible to carry 

 a series back to a stem cell and, rather than force a point. Ijlanks have 

 l)een left in the record. In the avian field, we are just l)eginning a study 

 of normal blood morphology and thus are now at the stage attained in 

 the human field 50 to 75 years ago. Wlien investigations on histology 

 and anatomy in the mammalian and human fields were being vigorously 

 pursued at about the turn of the century, the counterpart of such studies 

 in the avian field was neglected, perhaps because it was not realized that 

 the same kind of prerequisite information was needed to form the foundation 

 for later exact investigations in pouUry diseases, pathology, physiology, 

 embryology, and nutrition. 



Critical studies in the field of lilood diseases of poultry have been 

 retarded because a reference work on the morphology of normal and almor- 

 mal cells has not previously existed. The Atlas of Avian Hematology is 

 the first publication within the framework of a broad program on the basic 

 histology and anatomy of the fowl. It is hoped that the program can be 

 carried to completion. 



In the interim following the completion of tlie manuscript, new informa- 

 tion on the subject of avian and mammalian hematology has Ijcen published. 

 Therefore, a few references have been added on page 242. Two addenda, 

 one on page 93 and another on page 140, have l)een inserted at the end of 

 chapters so that pagination would not be disturbed. 



Alfred M. Lucas 

 Casimir Jamroz 



IV 



