WorldCat Identities

Melhado, Evan Marc 1946-

Works: 5 works in 29 publications in 1 language and 972 library holdings
Genres: History  Biography 
Roles: Editor
Classifications: QD22.B5, B
Publication Timeline
Publications about  Evan Marc Melhado Publications about Evan Marc Melhado
Publications by  Evan Marc Melhado Publications by Evan Marc Melhado
Most widely held works by Evan Marc Melhado
Money, power, and health care ( Book )
5 editions published between 1987 and 1988 in English and held by 381 WorldCat member libraries worldwide
Enlightenment science in the romantic era : the chemistry of Berzelius and its cultural setting ( Book )
9 editions published between 1992 and 2002 in English and held by 300 WorldCat member libraries worldwide
Jacob Berzelius, the emergence of his chemical system by Evan Marc Melhado ( Book )
10 editions published between 1981 and 1982 in English and held by 282 WorldCat member libraries worldwide
Jac. Berzelius, foundations and development of his chemistry by Evan Marc Melhado ( Book )
4 editions published between 1977 and 1987 in English and held by 8 WorldCat member libraries worldwide
The hemocytometer and its impact on progressive era medicine by Jack David Davis ( )
1 edition published in 1995 in English and held by 1 WorldCat member library worldwide
The hemocytometer was invented in the late nineteenth century. Physicians in Germany, France, and England were primarily responsible for its development. Information about the instrument and its diagnostic capabilities reached America through the immigration of foreign physicians, native-born physicians returning home after doing post-graduate work in Europe, trade catalogues, journal articles, and textbooks. The hemocytometer became a main-stay of American medical practice during the years of the Progressive Era. The hemocytometer's primary function was to enumerate or count the number of erythrocytes (red blood cells) and leucocytes (white blood cells) in a cubic millimeter of blood. Diseases such as anemia, or a decrease in red blood cells, and polycythemia, or an increase in red blood cells, had been identified by their physical manifestations for many years. With the advent of the hemocytometer, the physician was able to establish a correlation between the patient's outward physical symptoms and a quantitative determination of the number of cells that were actually contained within the circulatory system. The ability to "look within" the patient revolutionized the practice of medicine when it came to detecting blood disorders. White cells could also be counted on the hemocytometer. At first, physicians were unclear about the role that leucocytes played in disease. As the Progressive Era drew to a close, the physician not only identified increased white counts with infection and inflammation, but actually used the hemocytometer more frequently to count leucocytes than to count erythrocytes. The shift in emphasis from red cell counting to white cell counting on the hemocytometer was due to a better understanding of the causes of infection (the germ theory) and the body's response to an invasion by a foreign protein. Between Karl Vierordt's intial efforts to count red blood cells in the 1850s and the introduction of Karl Burker's counting device in the 1910s, the hemocytometer underwent a step-wise evolution that involved physicians from many nations. Georges Hayem, William Gowers, and Richard Thoma were only a few of the men who contributed to the development of the instrument. News about the instrument crossed the Atlantic from Europe in the form of both oral reports and written documents. Almost as soon as the hemocytometer arrived in this country, American physicians began to try to modify it to meet their own particular needs. The majority of the American modifications were never produced commercially, but they do show the extent to which the physician was motivated to insure an accurate counting of the cells. The disease states that were detectable with the hemocytometer covered a wide gamut. Chlorosis, pernicious anemia, leukemia, and polycythemia could be detected with the aid of the hemocytometer. Surgeons assessed the white count in anticipation of surgery for appendicitis, cholecystitis, and abscesses. Internists tried to judge the severity of an infection by monitoring the white count. The rapid rate with which blood counts were assimilated into hospital laboratory procedures attests to the growing importance of the hemocytometer to medical practice. Physicians ordered more blood work on their patients as the Progressive Era unfolded, and this fact helps underscore the growing reliance of the medical profession on the instrument. In summary, the hemocytometer was conceived in Europe, migrated to American shores, and was totally absorbed into American practice. By providing the physician with a way to evaluate quantitatively the patient's condition, it helped to revolutionize medical practice in the Progressive Era
Audience Level
Audience Level
  Kids General Special  
Audience level: 0.78 (from 0.76 for Money, pow ... to 0.98 for The hemocy ...)
Alternative Names
Melhado, Evan M.
Melhado, Evan Marc
Melhado, Evan Marc 1946-
English (29)