AIDS TO THE COMPLETE DETECTIVE

Dominion, Volume 30, Issue 160, 3 April 1937, Page 6 (Supplement)

AIDS TO THE COMPLETE DETECTIVE

The Microscope And Science

Imagine. for one crazy moment, that vou are a fugitive from justice, says Cyril Dalinalne, in the “Sunday Express.” Can. the law identify yon with the crime?

Mr. H. N. Robinson, in a fascinating new ’ book, “Science Versus Crime,” shows how science, the microscope and the camera can solve mysteries that are seemingly insoluble. Your fingers, for instance.

Already your paper is covered with your finger-prints, although you washed your hands five minutes ago.

These prints, photographed, measured and checked, could identify you among ten million people. No two prints are alike. Neither can you alter them.

Dillinger, the gangster, had his lingers treated with acid in an attempt Io disguise them. But when the police picked him up dead, his prints tallied exactly with those in the official records. Your clothes. However much you brush them, particles of dust remain. Every piece of matter in the world has its counterpart in dust. The investigator could analyse that dust. A few particles could tell him that you had been sawing wood or driving nails or using glue. Your boots might give a complete record of your recent movements. Layer by layer the investigator can remove the dust and mud. On top he might find City grime . . . lower down Southern Railway dust . . . lower still Sussex chalk.

To you the boots may look clean, but to the microscope they are a inap.

Why do you leave finger-prints? Because on the ridges of your fingers are millions of tiny pores, each connected with the nervous system. ' It is their function to exude a ceaseless stream of perspiration—99 per cent water and 1 per cent, fatty acids, in excitement the flow is increased, but it is always there. And a million times a day you leave your imprint on everything you touch.

Bullets are just as infallible as a means of identification. In America, someone is killed or wounded by bullets for every hour of every business day. All those bullets, being soft, carry the marks of the gun barrel that fired them—and no two gun barrels make the same markings.

The scientist has the suspect’s gum He fires a specimen bullet, places it in the microscope alongside the bullet in the crime. He rotates them. And if the scratches coincide in a single image then he’s found his man. Science can detect a lie. -C is no longer necessary—though it is still done—to torture a suspect into confession.

Instead, the suspect is seated comfortably before an instrument named a polygraph, or “lie detector.” The arm-cuff is bound about the upper arm, and the pneumograph-tube which measures the respiratory rate is tied about the chest.

Any change in breathing or blood pressure is recorded on a dial. Innocent questions-are asked first: “Do you play golf? ... Do you smoke? . . ■ Are you married?” Then, without warning, and in the same casual voice, comes the question: “Were you with John Smith on Thursday night?”

The suspect (if guilty) stiffens in spite of himself . . . imperceptibly he breathes a little quicker ... his heart pounds. And up jerks the recording needle.

Then there is photomicrography, in which the microscope and the camera combine to find clues that the eye cannot see. A match —one half in the criminal’s pocket, the other on the scene of the crime, can be microphotographed. And if the two ends mesh perfectly . . . All these crime detective methods leave you with this conviction —that it is not so much th e gentleman in the bowler hat that the modern criminal must fear to-day, but the gentleman with the test tube.