April 15, 1922] 



NATURE 



47 f 



investigation in which chemistry may be of service 

 in the administration of justice and with which medicine 

 as such may have httle or no concern. 



Mr. Lucas's book, as might be expected, is largely 



upon his experience of the methods of the 



iminal of the East, who, although he may not have 



II the appliances of his Occidental confrere, is scarcely 



resourceful. Indeed, some of the instances of 



jenuity and cunning to which Mr. Lucas incidentally 



fers may be recommended to the notice of writers 



detective stories. Invested with all the glamour 



the Orient, they would form a new departure in that 



iss of literature. 



The book is eminently practical, although it omits 



?tails of manipulation and methods of examination 



be found in standard treatises on chemical analysis. 



presupposes, in fact, that the chemist who embarks 



the subject of forensic chemistry is a well-trained 



ilyst with a sound knowledge of general chemistry. 



the same time, it gives in detail the special methods 



eded by the expert. In a short introductory chapter 



author offers very wise advice on the practice of 



rensic chemistry, evidently based upon personal 



)erience and a wide reading of notable trials. Legal 



)cedure, it must be admitted, is at times eminently- 



scientific. It might be supposed that the practice 



the law would tend to the cultivation of the scientific 



jirit in its practitioners, but observation shows that 



lis is far from being uniformly the case. This fact 



)nstitutes a difficulty with which the chemical expert 



occasionally to contend. The rules of conduct 



lich Mr. Lucas lays down may enable him to meet 



The value of the expert's testimony depends 



rgely upon the manner in which he presents it and 



i«pon the soundness and extent of knowledge with 



which he is able to support it. The lengths to which 



cross-examination may go are almost limitless, and 



side-issues may be developed which require wide and 



accurate general knowledge to deal with satisfactorily. 



At the same time, the forensic chemist must never 



forget that he is not an advocate or a partisan ; his 



single object should be to assist the court to a just 



decision. 



Every kind of criminal investigation with which 

 the chemist may be called upon to deal,. such as the 

 testing of blood-stains, the analytical examination 

 of bullets and other projectiles for firearms, of clothing, 

 counterfeit coins, documents, explosives and explosions, 

 fibres, finger-prints, fires and firearms, poisons and 

 narcotics, etc., is covered in Mr. Lucas's book. As 

 regards blood-testing in legal cases, the author rightly 

 insists that it should be undertaken only by those 

 who have considerable experience of the work. The 

 sources of error are frequently many, and the issues 

 NO. 2737, VOL. 109] 



may be most serious. The chapter dealing with this 

 subject is an excellent example of the care and caution 

 with which the author approaches any question of 

 chemical jurisprudence. Dealing with projectiles, it is 

 only necessary to recall the Monson trial to realise 

 how much may depend upon the analytical examina- 

 tion of projectiles, wads, and cartridges, the number 

 and width of marks made by the rifling of the 

 barrel, the direction of its twist, the presence of 

 rust, etc. As regards clothing, the author shows how 

 the examination of a waistcoat led to the detection 

 and conviction of a German spy during the war 

 of 1914-18. 



Counterfeit coining seems to be very prevalent in 

 Egypt. The coins are usually struck, and many, 

 we are told, are excellent imitations. A few illus- 

 trative cases are given, some of which display con- 

 siderable ingenuity in adapting primitive appliances 

 and apparatus intended for other purposes. The 

 examination of suspected documents in cases of sub- 

 stitution or forgery may require the testing of the 

 paper for the nature of the fibre, the recognition of 

 water-marks, the analysis of the ink employed, the 

 style of pen used, etc. Cases met with in Egypt 

 evidently present difficulties not usually present in 

 European countries. 



Knowledge gained during the war has undoubtedly 

 led to a great extension of the use of high explosives 

 for criminal purposes, especially in the form of 

 bombs as a means of assassination, and the chemico- 

 legal expert is not infrequently called upon to examine 

 them in connection with attempts at murder. Such 

 examinations are, of course, often attended with 

 danger, and need to be made with circumspection 

 and care. The precautions to be taken are set out 

 in some degree of detail. Of recent years Egypt 

 has been particularly fruitful of instances of the kind, 

 in which Mr. Lucas or his assistants would seem to 

 have had ample scope for the exercise of their courage, 

 skill, and ingenuity. 



But the " tyranny of space " forbids any further 

 attempt to illustrate the possibilities of chemistry 

 as applied to the detection of crime. For other 

 examples the reader may be referred to the book 

 under review. The possibilities are, in fact, boundless. 

 Mr. Lucas shows how the chemical examination of 

 stains and marks, dust and dirt, even of tobacco, 

 may afford clues which may lead to the conviction 

 of criminals. Indeed, one rises from the perusal of 

 his book with the feeling that the ideal forensic chemist 

 would be a combination of Sherlock Holmes with a 

 comprehensive compendium of general and analytical 

 chemistry such as might be embodied in a person of 

 whom fiction has hitherto afforded no example. 



