Digital identities

Fingerprints are unique to every individual. And so are biometrics.

Sherlock Holmes identified and used fingerprints in The Sign of Four, published in 1890. But Scotland Yard did not adopt fingerprinting as a methodology until a decade later. Holmes did not offer fingerprints as conclusive evidence, however, and the case was only solved by his usual formula: “Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.”

In 1880, Dr Henry Faulds, a Scottish surgeon working in Japan, published a paper in the scientific journal Nature, about the usefulness of fingerprints for identification and proposing a method to record them in ink. On an archaeological dig, Faulds had noticed the delicate impressions left by craftsmen on ancient clay fragments. Examining his own fingertips and those of friends, he realised that the pattern of ridges was unique to each individual.

In 1891, Croatian-born Argentinian criminologist, Juan Vucetich, began creating the first modern-style fingerprint archive. The following year, Francisca Rojas of Necochea, Argentina, was found with injuries in a house where her two sons had been murdered. Rojas accused a neighbour, but despite brutal interrogation, he would not confess to the crimes. Inspector Alvarez, a colleague of Vucetich, went to the scene and discovered a bloody thumb print on a door. Compared with Rojas’ prints, it was found to be identical and she confessed to the murder of her sons.

Mark Twain was the first American writer to use fingerprints in solving a fictitious crime. In his memoirs about life as a steamboat pilot, Life on the Mississippi (1883) – Chapter 31, “A Thumb-print and What Came of It,” – a character inspired by an old “French prison-keeper” uses a fingerprint to detect and prove a murderer’s identity:

“My apparatus was simple: a little red paint and a bit of white paper. I painted the ball of the client’s thumb, took a print of it on the paper, studied it that night, and revealed his fortune to him next day. What was my idea in this nonsense? It was this: When I was a youth, I knew an old Frenchman who had been a prison-keeper for thirty years, and he told me that there was one thing about a person which never changed, from the cradle to the grave – the lines in the ball of the thumb; and he said that these lines were never exactly alike in the thumbs of any two human beings. In these days, we photograph the new criminal, and hang his picture in the Rogues’ Gallery for future reference; but that Frenchman, in his day, used to take a print of the ball of a new prisoner’s thumb and put that away for future reference. He always said that pictures were no good – future disguises could make them useless. ‘The thumb’s the only sure thing,’ said he; ‘you can’t disguise that’.”

In the past, comparing fingerprints was a painstaking affair. Today, the process is digital, with scanners replacing ink. A computer programme identifies typical spots within the ridge pattern of a fingerprint. These include forks in the lines, spots and the location of the centre of the print. This biometrical data is then stored in a searchable database. In some countries, officials use fingerprint scanners during elections to make sure the people voting are registered and that they only vote once.

Smartphones now come with fingerprint recognition software. And some passports even have a digital fingerprint as part of the biometric information stored on an RFID (radio-frequency identification) chip. Other information on the chip includes a biometric passport photo, whose facial image is similar to a fingerprint: no two are alike.

Of course, as Marshall McLuhan, pointed out in From Cliché To Archetype (1970):

“As information itself becomes the largest business in the world, data banks know more about individual people than the people do themselves. The more the data banks record about each one of us, the less we exist.”


Published by

Philip Lee

Writer and musician who tries to join up the dots.

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