Pioneers in Hematology
Historically, Maxwell M. Wintrobe, Camille Dreyfus, and M. L. Verso were three important physicians and historians who authored numerous groundbreaking publications in the field of hematology. The history of the hemacytometer is closely tied to the rise in the field of hematology, which began in the mid-1700s. The following three pioneers were recognized by Wintrobe as the “Fathers of Hematology”: William Hewson, Gabriel Andral, and George Hayem. Hewson (1739-1774) was a physician and experimental physiologist from England. He was the first to establish that red corpuscles in blood (red blood cells) were individual particles, which engendered the idea that blood particles could be fixed and enumerated. Andral (1797-1876) was a general pathology professor at the Paris Medical School. He was able to measure water, solids, globules, and fibrins in blood by chemical analysis, which allowed him to associate diseases with changes in these elements. Hayem (1841-1933) developed one of the earliest hemacytometer devices for blood counting. He also discovered platelets, made important observations on morphological changes in red blood cells, and documented hematological diseases such as purpura and anemia. Another primary contributor to the field, Paul Ehrlich (1854-1915), was named the “father of chemotherapy”. His work was crucial for the development of colorimetric dyes that allowed physicians to differentiate leukocytes such as granulocytes, lymphocytes, monocytes, eosinophils, and basophils. The hematological research by these pioneers greatly contributed to the development of hemacytometer .
Evolution of the Hemacytometer
Many of the earliest recorded hematology experiments originated in France, where clinical medicine and blood-associated diseases were of great interest to those investigators. The first attempt to count red blood cells was proposed by Pierre-Adolphe Piorry (1794-1879). He was a strong advocate for the utilization of microscopes for clinical studies that focused on identifying blood-related diseases. In 1847, Piorry proposed to mix blood samples with a sodium sulfate solution and measure the volume of a drop of blood adhered to the sharp end of a needle. This was the first effort to describe how to analyze blood cells in a “known” volume of sample. This proposal was not accepted by the clinical communities of the time because the physicians were not trained scientists, and thus did not see the practicality of using microscopes for clinical medicine. As early as 1835, Gabriel Andral coauthored some of the earliest articles relating physical properties of blood to diseases . He was one of the first to characterize and quantify blood by specific physiological parameters such as globules, fibrin, water, and solid residues by numerical chemical analysis. In 1844, Alfred Donné (1801-1878) played an important role in promoting the use of microscopes to numerically determine the differences between different blood diseases. Like Piorry, Donné’s ideas were not accepted by the French medical community at that time. The three French scientists described here paved the way for blood research and laboratory medicine [1, 2].
By the mid-1850s, German scientists had transformed the traditional medical practices from sense and impression (physician’s feeling of patients’ issues) to laboratory medicine by numerical analysis. As a result, the employment of numerous full-time research scientists to teach and experiment initiated the development of the first exact red blood cell counting method by Karl Vierdordt (1818-1884). Vierdordt was a general medical practitioner who became an associate professor at Tübingen. In 1852, he published a paper entitled “Neue Methode der quantitative mikroskopischen Analyse des Blutes” or “New Method of Quantitative Microscopic Analysis of the Blood”, where he described his exact method for red blood cell counting . Vierdordt used a capillary tube with an internal diameter and length of 0.1-0.2 mm and 5-8 mm, respectively. After the blood was drawn into the tube, he was able to measure the internal diameter and length to accurately determine the volume of blood within the tube. Next, the blood sample was expelled from the tube and onto a glass plate coated with egg white, where the sample was allowed to dry. Finally, the glass plate was examined and the cells were counted using a microscope with a square micrometer incorporated into the ocular section. Although this method was tedious and time-consuming, requiring at least three hours for preparation and counting, it was exceedingly accurate.
Vierdordt also published a second article entitled “Zählungen der Blutkörperchen des Menschen” or “Blood Corpuscular Counts in Man”, presenting nine counting results using his own blood, which averaged ~ 5,174,400 cells/mm3 or 5.17 x 109 cells/ml . His work demonstrated the first accurate assessment of red blood cells [1, 2].
Several improvements were made after Karl Vierdordt’s design. Herman Welcker (1822-1897), a student of Vierdordt’s, incorporated ruling on the glass slide in 1854. In 1855, Antonj Cramer (1822-1855) developed a counting chamber by cementing parallel bands on a slide and a thin glass slide on the top to create a volume of 0.011 µl in the chamber. He also incorporated 48 oblong rulings in the microscope to facilitate manual counting that corresponded to a total of 0.172 mm2. This method could determine sample concentration by the known volume in the chamber. In addition, the capillary action allowed for more uniform distribution of the cells [1, 2].