Editing Sherlock Holmes (section)

===Forensic science===
[[File:Mikroskop-seibert hg.jpg|thumb|right|upright|alt=See caption|19th-century Seibert microscope]]

Though Holmes is famed for his reasoning capabilities, his investigative technique relies heavily on the acquisition of hard evidence. Many of the techniques he employs in the stories were at the time in their infancy.<ref>{{cite encyclopedia|url=https://www.britannica.com/topic/Sherlock-Holmes-Pioneer-in-Forensic-Science-1976713|title=Sherlock Holmes: Pioneer in Forensic Science|encyclopedia=Encyclopaedia Britannica|access-date=20 December 2019|archive-date=20 December 2019|archive-url=https://web.archive.org/web/20191220224925/https://www.britannica.com/topic/Sherlock-Holmes-Pioneer-in-Forensic-Science-1976713|url-status=live}}</ref><ref name=":4" />

The detective is particularly skilled in the analysis of [[trace evidence]] and other physical evidence, including latent prints (such as footprints, hoof prints, and shoe and tire impressions) to identify actions at a crime scene,<ref>''A Study in Scarlet'', "[[The Adventure of Silver Blaze]]", "The Adventure of the Priory School", ''The Hound of the Baskervilles'', "[[The Boscombe Valley Mystery]]"</ref> using tobacco ashes and cigarette butts to identify criminals,<ref>"[[The Adventure of the Resident Patient]]", ''The Hound of the Baskervilles''</ref> utilizing [[questioned document examination|handwriting analysis]] and [[graphology]],<ref>"[[The Adventure of the Reigate Squire|The Reigate Squires]]", "The Man with the Twisted Lip"</ref> comparing [[Typewriter|typewritten]] letters to expose a fraud,<ref>Klinger I, pp. 99-100—"A Case of Identity"</ref> using gunpowder residue to expose two murderers,<ref>Klinger I, p. 578—"The Reigate Squires"</ref> and analyzing small pieces of human remains to expose two murders.<ref>Klinger I, pp. 438-439—"The Cardboard Box"</ref>

Because of the small scale of much of his evidence, the detective often uses a magnifying glass at the scene and an [[optical microscope]] at his Baker Street lodgings. He uses [[analytical chemistry]] for [[blood residue]] analysis and [[toxicology]] to detect poisons; Holmes's home chemistry laboratory is mentioned in "[[The Adventure of the Naval Treaty|The Naval Treaty]]".<ref>Klinger I, p. 670—"The Naval Treaty"</ref> [[Ballistics]] feature in "The Adventure of the Empty House" when spent bullets are recovered to be matched with a suspected murder weapon, a practice which became regular police procedure only some fifteen years after the story was published.<ref>Klinger II, p. 814—"The Adventure of the Empty House"</ref>

Laura J. Snyder has examined Holmes's methods in the context of mid- to late-19th-century criminology, demonstrating that, while sometimes in advance of what official investigative departments were formally using at the time, they were based upon existing methods and techniques. For example, fingerprints were proposed to be distinct in Conan Doyle's day, and while Holmes used a thumbprint to solve a crime in "[[The Adventure of the Norwood Builder]]" (generally held to be set in 1895), the story was published in 1903, two years after [[Henry Classification System|Scotland Yard's fingerprint bureau]] opened.<ref name=":4">{{cite journal|last=Snyder|first=Laura J.|year=2004|title=Sherlock Holmes: scientific detective|journal=Endeavour|volume=28|issue=3|pages=104–108|doi=10.1016/j.endeavour.2004.07.007|pmid=15350761}}</ref><ref>Klinger II, pp. 860-863</ref> Though the effect of the Holmes stories on the development of forensic science has thus often been overstated, Holmes inspired future generations of forensic scientists to think scientifically and analytically.<ref>{{Cite web |last=Schwartz |first=Roy |date=2022-05-20 |title=Opinion: The fictional character who changed the science of solving crime |url=https://www.cnn.com/2022/05/20/opinions/sherlock-holmes-father-of-modern-forensic-science-schwartz/index.html |access-date=2022-05-21 |website=CNN |language=en |archive-date=21 May 2022 |archive-url=https://web.archive.org/web/20220521182548/https://www.cnn.com/2022/05/20/opinions/sherlock-holmes-father-of-modern-forensic-science-schwartz/index.html |url-status=live }}</ref>