trigonometric functions (for which the author appears to be under the impression that the tables of values were found by drawing and measuring triangles!).

And so the rest of the book proceeds. Formula after formula is given and usually derived at length, but rarely with any worked examples, and sometimes with no explanation of how they might be useful. For example, how would an accident investigator use a formula for determining the range of a projectile, given its launch velocity? Often the work of some other person is referred to-"Professor so-and-so says this, Dr. Someone Else says that"-sometimes giving a particular individual credit for a quite commonplace and obvious formula, but they are mostly names unknown to this reviewer, and no proper references are given at any stage.

The subjects covered range over cornering and overturning, airborne motion, intersection collisions and motorcycle and heavy vehicle problems. But throughout one feels that the author does not quite fully understand what he is doing. For example, he spends five and a half pages developing an equation for the distance travelled by a car which drives downhill and is launched off a cliff. Then he takes another four and a half pages to treat the mathematically identical problem of an uphill launch. Or again, consider the problem of the weight transfer experienced by a two-axled vehicle during braking: the formula for this is the same whether it is a motorcycle, car or lorry, and we are indeed given the same one for motor cycles and lorries (although the connection between them is not pointed out). But for motor cars something quite different, amounting to a gross simplification, is produced. The reason we want to know the amount of weight transfer is to be able to calculate the speed of a vehicle which has skidded without locking all its wheels, and I should say that I do not think the way Ravensdale has formulated the solution is correct.

There is also some discussion of the use of tachographs, although we are promised a more complete exposition in Volume Three. But here we are told that impact speeds can be determined after the vehicle's wheels have locked (not so), and that the author has a system whereby the recording can be broken down into fractions of a second-which is interesting when one considers that the instrument's clock only advances the chart once per second!

To summarise, I would say that this is a book which covers much the same ground as the locally produced manuals which are given out on police accident investigation courses, and does not, in my view, significantly improve on them. Imperial and not metric units are used throughout, and the language and symbolism used is mid-Atlantic-there are passages which I feel would puzzle readers on both sides of the ocean. And finally, many may regard the cost as rather high.

RFL

A CLASSIC ON THE WORK BENCH

Poison Detection in Human Organs (4th edn) Alan S Curry (Charles C Thomas, Springfield, Illinois, 1988, 335 pp, index, ISBN 0-395-05425-8, $54.50)

This long-awaited 4th edition of Dr. Curry's classic text-book reflects many of the advances in analytical technology which have taken place since the last edition appeared in 1976. At the same time much of the earlier material has been retained and expanded.

JFSS 1989; 29(2): 141-147 143

Part I deals with analysis in the living patient and covers Emergency Toxicology and Drug Abuse Screening. Part I1 is concerned with post-mortem investigations and Part 111 deals alphabetically with over 100 poisonous substances ranging from agricultural pesticides and toxic metals to volatile solvents and drugs. For each substance, details of qualitative and quantitative methods are presented together with an interpretation of the findings.

The volume is packed with new information, all of which has been critically appraised by the author. Like its predecessors, the book will find a place in the library and on the desk-top as a work of reference, and spread out on the laboratory bench as a working manual.

BW

KNIGHTS OF PLEASURE - AND A LImLE PAIN

Legal Aspects of Medical Practice 4th edition Bernard Knight (Churchill Livingstone, 1987 341 pp, index, ISBN 0 443 03781 7, £9.95)

Rumour has it that we are shortly to have a long Knight; for me, Legal Aspects of Medical Practice has always been an exciting Knight and I was looking forward to seeing what improvements were possible. As a result of a systematic read, I still find that it is the most enjoyable text on forensic medicine available but that, in the manner of a Curried curate's egg, it is not so good in parts.

The new edition is 40 pages longer than its predecessor but the typeface and pagination are different (incidentally, I greatly prefer the new style). As a result, there is not a great deal of room for new material; what appears is, quite rightly, concentrated on medical jurisprudence - or the effect of the law on medical practice.

The section on confidentiality has been up-dated and expanded and is undoubtedly useful. I was slightly surprised to find no reference to the Police and Criminal Evidence Act 1984 which so concerned the medical establishment. The destination of disclosed medical documents is now governed by the Supreme Court Act 1981; in this connection, I would have liked some discussion of the fate of, say, internal hospital accident reports which seems to me to be a matter for considerable concern. I very much appreciated the upgraded section on failure to attend patients but, in my view, the new text gives insufficient attention to the consent-based action for negligence which is steadily increasing in importance - it is a particular issue in unsuccessful sterilisation under which heading it is not addressed. I noted that the old paragraph on consent of the patient as a defence against an accusation of negligence has been removed; this seems unfortunate as the additional material on informed consent could well do with being expanded. A mention of wardship proceedings as an answer to the unreasonable parent might, also, have been included.

As to forensic pathology, I found the new section on temperature and the time of death extremely useful and it is just the sort of thing that needs to be explained to the doctor who is inexperienced in legal work. The asphyxias are particularly well set out but, by contrast, I wonder if criminal abortion now commands the scarce resource of space that it is given; a discussion of the antenatal detection of foetal abnormality might be more appropriate - but we are all guilty! Professor Knight is,

144 JFSS 1989; 29(2): 141-147