Editing Pathophysiology (section)

===Nineteenth century===

====Reductionism====

In Germany in the 1830s, [[Johannes Peter Müller|Johannes Müller]] led the establishment of physiology research autonomous from medical research.  In 1843, the [[Berlin Physical Society]] was founded in part to purge biology and medicine of [[vitalism]], and in 1847 [[Hermann von Helmholtz]], who joined the Society in 1845, published the paper "On the conservation of energy", highly influential to reduce physiology's research foundation to physical sciences. In the late 1850s, German [[anatomical pathology|anatomical pathologist]] [[Rudolf Virchow]], a former student of Müller, directed focus to the cell, establishing [[Cytopathology|cytology]] as the focus of physiological research. He also recognized pathophysiology as a distinct discipline, arguing that it should rely on clinical observation and experimentation rather than purely anatomical pathology.<ref name=Churilov_2015/> Virchow’s influence extended to his student [[Julius Cohnheim]], who pioneered [[experimental pathology]] and the usage of [[intravital microscopy]], further advancing the study of pathophysiology.<ref name=Churilov_2015/>

====Germ theory====
By 1863, motivated by [[Louis Pasteur]]'s report on fermentation to [[butyric acid]], fellow Frenchman [[Casimir Davaine]] identified a microorganism as the crucial causal agent of the cattle disease [[anthrax]], but its routinely vanishing from blood left other scientists inferring it a mere byproduct of [[putrefaction]].<ref>{{cite journal | author = Théodoridès J | title = Casimir Davaine (1812-1882): A precursor of Pasteur | journal = Medical History | volume = 10 | issue = 2 | pages = 155–65 | year = 1966 | pmid = 5325873 | pmc = 1033586 | doi = 10.1017/S0025727300010942 }}</ref>  In 1876, upon [[Ferdinand Cohn]]'s report of a tiny spore stage of a bacterial species, the fellow German [[Robert Koch]] isolated Davaine's ''bacterides'' in [[pure culture]] —a pivotal step that would establish [[bacteriology]] as a distinct discipline— identified a spore stage, applied [[Jakob Henle]]'s postulates, and confirmed Davaine's conclusion, a major feat for [[experimental pathology]]. Pasteur and colleagues followed up with [[ecology|ecological]] investigations confirming its role in the natural environment via spores in soil.

Also, as to [[sepsis]], Davaine had injected rabbits with a highly diluted, tiny amount of putrid blood, duplicated disease, and used the term ''ferment of putrefaction'', but it was unclear whether this referred as did Pasteur's term ''ferment'' to a microorganism or, as it did for many others, to a chemical.<ref name=Bulloch143-148>Bulloch, William, [https://books.google.com/books/about/The_history_of_bacteriology.html?id=TQgZAAAAMAAJ ''The History of Bacteriology''] (Oxford: Oxford University Press, 1938 & 1960 / New York: Dover Publications, 1979), p 143–144, 147-148</ref>  In 1878, Koch published ''Aetiology of Traumatic Infective Diseases'', unlike any previous work, where in 80 pages Koch, as noted by a historian, "was able to show, in a manner practically conclusive, that a number of diseases, differing clinically, anatomically, and in [[aetiology]], can be produced experimentally by the injection of putrid materials into animals."<ref name=Bulloch143-148/>  Koch used bacteriology and the new staining methods with [[aniline dye]]s to identify particular microorganisms for each.<ref name=Bulloch143-148/> [[Germ theory of disease]] crystallized the concept of cause—presumably identifiable by scientific investigation.<ref>{{cite journal | author = Carter KC | title = Germ theory, hysteria, and Freud's early work in psychopathology | journal = Medical History | volume = 24 | issue = 3 | pages = 259–74 | year = 1980 | pmid = 6997653 | pmc = 1082654 | doi = 10.1017/S002572730004031X }}</ref>

====Scientific medicine====

The American physician [[William Henry Welch|William Welch]] trained in German pathology from 1876 to 1878, including under [[Julius Cohnheim|Cohnheim]], and opened America's first scientific laboratory —a pathology laboratory— at [[Bellevue Hospital]] in New York City in 1878.<ref name=Silverman>{{cite journal | author = Silverman BD | title = William Henry Welch (1850-1934): The road to Johns Hopkins | journal = Proceedings | volume = 24 | issue = 3 | pages = 236–42 | year = 2011 | pmid = 21738298 | pmc = 3124910 | doi=10.1080/08998280.2011.11928722}}</ref>  Welch's course drew enrollment from students at other medical schools, which responded by opening their own pathology laboratories.<ref name=Silverman/>  Once appointed by [[Daniel Coit Gilman]], upon advice by [[John Shaw Billings]], as founding dean of the medical school of the newly forming [[Johns Hopkins University]] that Gilman, as its first president, was planning, Welch traveled again to Germany for training in Koch's bacteriology in 1883.<ref name=Silverman/>  Welch returned to America but moved to Baltimore, eager to overhaul American medicine, while blending Virchow's anatomical pathology, Cohnheim's experimental pathology, and Koch's bacteriology.<ref name=Benson>{{cite journal | author = Benson KR | title = Welch, Sedgwick, and the Hopkins model of hygiene | journal = The Yale Journal of Biology and Medicine | volume = 72 | issue = 5 | pages = 313–20 | year = 1999 | pmid = 11049162 | pmc = 2579023 }}</ref>  Hopkins medical school, led by the "Four Horsemen" —Welch, [[William Osler]], [[Howard A. Kelly|Howard Kelly]], and [[William Stewart Halsted|William Halsted]]— opened at last in 1893 as America's first medical school devoted to teaching German scientific medicine, so called.<ref name=Silverman/>