Early anatomists described the ridges of the fingers, but interest in modern fingerprint identification dates from 1880, when the British scientific journal Nature published letters by the Englishmen Henry Faulds and William James Herschel describing the uniqueness and permanence of fingerprints. Their observations were experimentally verified by the English scientist Sir Francis Galton, who suggested the first elementary system for classifying fingerprints based on grouping the patterns into arches, loops, and whorls. Galton's system served as the basis for the fingerprint classification systems developed by Sir Edward R. Henry, who later became chief commissioner of the London metropolitan police, and by Juan Vucetich of Argentina. His system is still used in most Spanish-speaking countries. The information obtained in this way is incorporated in a concise formula, which is known as the individual's fingerprint classification.
Whorls are usually circular or spiral in shape.
Arches have a moundlike contour, while tented arches have a spikelike or steeplelike appearance in the centre. The most common pattern is the ulnar loop. Dactyloscopy, the technique of fingerprinting, involves cleaning the fingers in benzene or ether, drying them, then rolling the balls of each over a glass surface coated with printer's ink. Each finger is then carefully rolled on prepared cards according to an exact technique designed to obtain a light gray impression with clear spaces showing between each ridge so that the ridges may be counted and traced. Simultaneous impressions are also taken of all fingers and thumbs.