Pfeiffer, Richard Friedrich Johannes (1858-1945)

German physician

Richard Pfeiffer conducted fundamental research on many aspects of bacteriology, most notably bacteriolysis ("Pfeiffer's phenomenon"), which is the destruction of bacteria by dissolution, usually following the introduction of sera, specific antibodies, or hypotonic solutions into host animals.

Pfeiffer was born on March 27, 1858, to a German family in the Polish town of Zduny, Poznania, a province then governed by Prussia and later by Germany as Posen, but after World War II again by Poland as Ksiestwo Poznanskie. After studying medicine at the Kaiser Wilhelm Academy in Berlin from 1875 to 1879, he served Germany as an army physician and surgeon from 1879 to 1889. He received his M.D. at Berlin in 1880, taught bacteriology at Wiesbaden, Germany, from 1884 to 1887, then returned to Berlin to become the assistant of Robert Koch (1843–1910) at the Institute of Hygiene from 1887 to 1891. Upon earning his habilitation (roughly the equivalent of a Ph.D.) in bacteriology and hygiene at Berlin in 1891, he became head of the Scientific Department of the Institute for Infectious Diseases and three years later was promoted to full professor.

Pfeiffer accompanied Koch to India in 1897 to study bubonic plague and to Italy in 1898 to study cholera. He moved from Berlin to Königsberg, East Prussia (now Kaliningrad, Russia) in 1899 to become professor of hygiene at that city's university. He held the same position at the University of Breslau, Silesia, (now Wroclaw, Poland) from 1909 until his retirement in 1926, when he was succeeded by his friend Carl Prausnitz (1876–1963), a pioneer in the field of clinical allergy.

While serving the German army in World War I as a hygiene inspector on the Western front, Pfeiffer achieved the rank of general, won the Iron Cross, and personally intervened to save the lives of captured French microbiologists Lèon Charles Albert Calmette (1863–1933) and Camille Guèrin (1872–1961), co-inventors of the BCG (bacille biliè de Calmette-Guèrin) vaccine against tuberculosis .

Pfeiffer discovered many essential bacteriological facts, mostly in the 1890s. Several processes, phenomena, organisms, and items of equipment are named after him. A Petri dish of agar with a small quantity of blood smeared across the surface is called "Pfeiffer's agar." In 1891, he discovered a genus of bacteria, Pfeifferella, which has since been reclassified within the genus Pseudomonas. In 1892 he discovered and named Haemophilus influenzae, sometimes called "Pfeiffer's bacillus," which he incorrectly believed to be the cause of influenza . It does create some respiratory infections, as well as meningitis and conjunctivitis, but in the 1930s, other scientists learned that influenza is actually a caused by a virus.

Collaborating with Vasily Isayevich Isayev (1854–1911), he reported in 1894 and 1895 what became known as "Pfeiffer's phenomenon," immunization against cholera due to bacteriolysis, the dissolution of bacteria, by the injection of serum from an immune animal. In 1894, he noticed that a certain heat-resistant toxic substance was released into solution from the cell wall of Vibrio cholerae only after the cell had disintegrated. Following this observation he coined the term "endotoxin" to refer to potentially toxic polysaccharide or phospholipid macromolecules that form an integral part of the cell wall of Gram-negative bacteria. In 1895, he observed bactericidal substances in the blood and named them Antikörper ("antibodies").

Pfeiffer died on September 15, 1945 in the German-Silesian resort city of Bad Landeck, which, after the Potsdam Conference of July 17 to August 2, 1945, became Ladek Zdroj, Poland.

See also Antibody and antigen; Antibody formation and kinetics; Bacteria and bacterial infection; Bactericidal, bacteriostatic; Bubonic plague; Epidemics, bacterial; Infection and resistance; Meningitis, bacterial and viral; Pseudomonas; Serology; Typhoid fever; Typhus