"Histology of the Blood, Normal and Pathological" by Paul Ehrlich and Adolf Lazarus is a scientific publication written in the late 19th century. This work serves as a comprehensive examination of the blood, exploring its normal and pathological states, with an emphasis on the morphological characteristics of blood cells and their clinical significance. The book is foundational for those studying blood pathology and aims to enhance the understanding of hematological diseases through detailed microscopic observations. The opening of this work features a preface by G. Sims Woodhead, discussing the historical context of blood pathology and the advances made in the field, particularly highlighting the contributions of Ehrlich. It underscores the complexity of blood disorders and the necessity of integrating extensive clinical observation with experimental methods. Woodhead emphasizes that the work distills significant amounts of information regarding blood changes during disease, and serves as a critical resource for both practitioners and students in medicine. The initial sections introduce the definitions and clinical methods pertinent to blood examination, laying the groundwork for a deeper exploration of blood morphology and pathology to come. (This is an automatically generated summary.)