The plan of identifying people by their finger-prints, although at first used only on criminals, is now put to many other uses. It was introduced originally in India, where it was of very great assistance to the British authorities in impressing the natives with the fact that at last no evasion of positive identification of culprits was possible. It was later taken up by the Scotland Yard authorities in England, and its use has since spread to practically every country in the civilized world.

It has been proven, to the entire satisfaction of everyone who has ever made a careful study of the subject, that every human being has a marking on his or her fingers which is different from that of any other person on earth. Not only is it sure that no one else has a thumb or finger marked like yours, but it has also been established beyond dispute that every little detail will continue peculiar to your fingers as long as you have them.

There are many ways in which this knowledge is used to advantage; two methods now employed are particularly valuable. It is seldom that an unpremeditated crime is committed without its author leaving finger-marks on some object which is unconsciously touched, such as silver plate, cash boxes or safes, glassware or windows, polished wood-work, etc., and very often the professional criminal also neglects to take precautions against leaving his signature behind him. It is then a simple matter for the police to collect such marks for comparison with the finger prints of anyone to whom suspicion may be directed.

The plan has also been utilized a great deal in recent years for the identification of enlisted men in the army and navy. Finger-prints are made, immediately upon enlistment, of each separate ringer and thumb of both hands. Group impressions are also taken with the four fingers of each hand pressed down simultaneously. When needed for any particular purpose, such finger-prints are usually enlarged by means of a special camera, to five times their natural size.