KANGAROO'S AND HUMAN HAIR, AND THE HAIR OF A CAT AND A DOG 164 FIBRES OF CHINESE SILK 164 RABBIT'S AND HORSE-HAIR 166 WOOL FIBRES FROM DIFFERENT BREEDS OF SHEEP 168 COTTON AND FLAX FIBRES 170 ANNE TURNER 172 Science and the Criminal CHAPTER I INTRODUCTION Conflict between the Law-maker and the Law-breaker--Illustrations of Deductive Reasoning in Criminal Cases--Scientific Evidence--Scientific Assistance for the Accused--Instances of Advantages of Conflict of Scientific Evidence--Scientific Partisanship. In the constant state of warfare between the law-maker and the law-breaker, which began when mankind first organised itself into communities and has existed ever since, every new invention or practical application of scientific discovery has supplied each side with new weapons frequently of much greater precision. The advantage thus conferred tends to be on the side of the law-maker but not invariably so; for in spite of all the facilities of investigation now available it is surprising how many crimes remain undetected, or how frequently in suspicious cases it is impossible to discover the truth. The law-breaker's primitive weapon of natural cunning has thus often proved more than a match for all the weapons at the disposal, of his opponent. There is much to be said, therefore, for the suggestion which has recently been put forward on many sides that a department specially trained for the work of criminal investigation should be created. Under the present conditions the rank and file of the detective force, recruited as it is from the best of the uniformed policemen, contains many men of acute intellect and reasoning capacity, but it cannot be doubted but that in many cases their efficiency would have been enormously increased by a scientific training. The present system somewhat recalls that under which doctors acquired their knowledge of medicine in the early part of last century. Their mistakes taught them what not to do, but in the meantime the patient sometimes died. Methods of scientific reasoning so as to draw deductions from observed facts cannot be acquired by solitary night watches upon a "beat," nor does the facility for breaking up a tangle in traffic which the constable acquires as the outcome of his daily duties, necessarily render him more capable of extricating from a mass of confused details the essential facts upon which stress should be laid.