Benedict Cumberbatch
'Sherlock' TV Programme. - 2014
Why Sherlock Holmes is the world's best-loved detective
05:17 - Source: CNN

Editor’s Note: Roy Schwartz is a critic and historian of popular culture. Follow him on Twitter, Instagram, Facebook and at royschwartz.com. The views expressed here are his own. View more opinion at CNN.

CNN  — 

May 22 is “Sherlock Holmes Day,” honoring the birthday of his creator, Sir Arthur Conan Doyle. Holmes, who turns 135 this year, is one of the most famous literary characters in the world and probably the most famous detective.

He’s come to be referenced as a historical figure rather than a fictional one (often at the expense of his actual author), with countless legends surrounding him. Perhaps the most popular is that he invented modern forensic science.

This particular aspect of Holmes lore has been addressed in articles, books, documentaries, and college courses and is even cited by forensic experts. But is it really true? Did Sherlock Holmes (meaning Doyle) invent crime-solving methods like fingerprinting and blood testing years and even decades before law enforcement?

If he did, it would mean that, aside from entertaining generations of readers and viewers and inspiring dozens of other popular characters like Batman and House, M.D., he also deserves credit for helping solve thousands, if not millions, of crimes in the real world.

The origin of Holmes’ forensic expertise

In his very first story, 1887’s “A Study in Scarlet,” Doyle describes Holmes as “well up in anatomy, and … a first-class chemist,” who “has never taken out any systematic medical classes” but has nonetheless “amassed a lot of … knowledge which would astonish his professors.” Holmes didn’t have official forensic training simply because there was none; the first forensic science program was established at the University of Lausanne, Switzerland, in 1909.

Sir Arthur Conan Doyle is seen in this 1922 photo. (AP Photo)

Where Holmes did get his prodigious medical knowledge was from his creator. Doyle was a practicing ophthalmologist who wrote as a hobby, much like Holmes’ partner and chronicler, Dr. Watson.

Holmes is also based on a real physician, Dr. Joseph Bell, a mentor of Doyle’s at the University of Edinburgh, who had even assisted police in murder investigations. In 1892, Doyle wrote to Bell: “It is most certainly to you that I owe Sherlock Holmes … I do not think that his analytical work is in the least an exaggeration of some effects which I have seen you produce in the out patient ward.”

At a time when solving crimes mostly consisted of collecting eyewitness accounts and rounding up the usual suspects (often to coerce a confession), Doyle imported the methodical examination and evidence-based deduction of medicine to police work.

Holmes didn’t invent the idea of using science to solve crimes, but he did popularize it.

Holmes’ magnifying glass

Of the various forensic techniques attributed to Holmes, the most famous is the use of a magnifying glass. It’s as much a part of his iconic image as the deerstalker cap and calabash pipe.

It’s first mentioned in “A Study in Scarlet,” which does mark the first time a magnifying glass is used in a work of fiction to examine a crime scene, even though magnifying glasses in different forms had been around for centuries.

It’s unclear whether magnifying glasses were used in investigative fieldwork before then, but Sir Sydney Smith (1883-1969), professor of forensic medicine and dean of medicine at the University of Edinburgh and one of the world’s preeminent forensic experts, credited Holmes with the idea.

Blood testing

Also in “A Study in Scarlet,” Holmes declares: “I have found a re-agent which is precipitated by hoemoglobin, and by nothing else … it gives us an infallible test for blood stains … The old guaiacum test was very clumsy and uncertain. So is the microscopic examination for blood corpuscles. The latter is valueless if the stains are a few hours old.”

A reproduction of a copy of the book 'A Study in Scarlet' by Sir Arthur Conan Doyle, 8th December 1986. (Photo by Georges De Keerle/Getty Images)

Holmes’s discovery does predate the first reliable blood test in real life by more than a decade, either the Uhlenhuth Test created in 1900 or the Kastle Meyer Test created in 1903.

Holmes is right that the Guaiacum Test – invented in 1864, using tree resin acid to turn bloodstains blue – is inconclusive, but it is fairly accurate and in fact, still used today.

In truth, the Teichmann Test had been in use since 1853, a conclusive test based on microcrystal formation in reaction to hemoglobin. This is presumably the microscopic examination Holmes was referring to. While it does require a microscope and is not conducted on-scene, and bloodstains that are insoluble or diffused can result in a false negative, Holmes was wrong that the test is only effective for fresh blood. It’s been successfully used to identify stains as old as 20 years.

Blood could not be accurately matched to an individual until DNA profiling was created in 1984 and first used forensically in 1986.

The reality of fingerprints

Holmes is also credited as a pioneer of fingerprint analysis, first referenced in 1890’s “The Sign of the Four,” more than a decade before Scotland Yard fully used them.

While that’s technically true, the British had been using handprints in Bengal, India, since 1858 as an alternative to locals’ signatures. Using hand and finger impressions for personal identification dates back to ancient Mesopotamia, and as a way to identify perpetrators of crimes to at least 300 BCE China.

Hand print with reference grid superimposed, used to identify criminals. Dated 19th Century. (Photo by: Universal History Archive/Universal Images Group via Getty Images)

American science journals proposed using prints found at crime scenes