Evidence Act 1984 Codes of Practice published by HMSO. It deals with the problems of human rights, and of self incrimination. Then, more particularly, it deals with the problems of persons who have a mental handicap. The Codes of Practice provide that the questioning of Huch persons should take place whilst "an appropriate adult" is present. The booklet gives guide-lines for both the person conducting the interview and this "appropriate adult". A particularly telling part of the booklet is the section entitled " 'Yes' to Everything", where persons suffering from a mental handicap are likely to be especially open to suggestion. The booklet also gives an interesting bibliography for further reading.

In view of the modest cost it may be that this booklet could be available for reference in most police stations, for occasions where "an appropriate adult" is called to the police station to attend the interview of a person with a mental handicap.

RCW

VARYING DEPTHS

Forensic Science Handbook Volume I1 R Saferstein (Ed) (Prentice Hall, Englewood Cliffs, New Jersey; 1987, 461 pp, Index, ISBN 0 13 326877 2)

This is an 8 chapter supplement to a first book, also edited by Saferstein and sold under the same title. The book is well presented although the contents pages could be more effectively and less confusingly displayed. Chapters are written by an expert in each field and cover, in order, the topics of "Mountebanks amongst forensic scientists, forensic capillary column gas chromatography, forensic identification of controlled substances, microscopy and microchem- istry of phy~ical evidence, the forensic aspects of textile fibre examination, paternity testing, the identification and individualisation of semen stains and firearms identification". All chapters are well referenced and easy to read but as would be expected from such a book the depth of individual articles differ. For example, the chapter on capillary column gas chromatography is an introductory one while that on paternity testing goes into considerably more depth. The book is very much a product of the American market and does reflect a parochial view, especially in the referencing to chapters and particularly in the case laws and drug laws. Generally, with the exception of one chapter, the book is remarkably free from errors. The exception is the chapter on the forensic identification of controlled substances which repeatedly gives, amongst other errors, incorrect formulae (e.g. morphine, methylam- phetamine) for drugs and reactants, has the wrong botanical name for ergo1 (Claviceps purpurea not clavica purpurea), and makes on two occasions a complete mis-statement that Cannabk sativa is identified by wide non glandular covering hairs, when the major characteristic is the presence of glandular tricomes (hairs) which exude the Cannabinoids. In spite of these criticisms, this is a book which will be widely read and, I suspect, often produced in court and will find a place in the library of every forensic science laboratory.

BC