240 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS XI: Notes on experimental techniques employed in the quantitative investigation of fats. The individual sections are supported by comprehensive bibliographies, some of the references being as recent as early 1964. Excellent indexes include a general index of subjects, indexes of individual fats and waxes, plant families, individual fatty acids and individual glycerides. This first-class volume is absolutely essential for every cosmetics laboratory and will serve as a major reference work on oils and fats for many years to come. R. P. REEVES.. THE KJELDAHL METHOD FOR ORGANIC NITROGEN.. R. B. Bradstreet. Pp. viii q- 239 q- Ill. (1965). Academic Press, New York and London. 76s. The Kjeldahl method is an example par excellence of a well-established analytical method of which the theoretical chemistry is rather obscure. The many' modifications which have been proposed to the method have consequently tended to. be ad hoc improvements directed at a particular type of sample. In this monograph, Bradstreet has attempted to draw together the various strands of research, both the relatively few concerned with elucidation of mechanisms and the many with the principal aim of improvement and adaptation of the method. The result is an inter- esting and readable review. The eight-page Introduction is a brief history reminding us of the origin of the method in the Carlsberg Laboratories in Denmark and Kjeldahl's first publication in 1888. The 47 references quoted are selected to illustrate the 80 years of its history. The second chapter entitled "Kjeldahl digestion" discusses, in 81 pages, acid requirements, salt additions, oxidizing agents, boiling time and catalysts. The amounts of acid consumed by various types of sample and the effect of the salt addition in raising the temperature of digestion are critically examined the advantages. of using oxidizing agents prior to the digestion proper are discussed, as are the re- ducing agents which may be used to enable substances containing nitrogen directly bonded to oxygen to be determined. The function attributed (p. 61) to salicylic acid in preventing loss of nitrate nitrogen, viz. to supply a source of sulphur dioxide, is quite different to that which many chemists faithfully imbibed from standard texts, where salicylic acid is des- cribed as a substance that can be readily nitrated. Unfortunately for such illusions logic appears to be on the author's side. The controversy over catalysts has received due attention concluding with reasons for the general acceptance of mercury nowa- days. The following chapter on digestion procedure overlaps in subject matter with the previous one but this is admitted by the author as a necessary fault, if the form of sub-division of the book is accepted and yet completeness is to be maintained within each part of the discussion. The chapter discusses treatments necessary for naturaI products from cereals and soils to coal and petroleum, and for organic substances according to function, and ends with eight pages devoted to "sub-micro" methods where the amount of nitrogen is within the range 0-100/•g. The reviewer deprecates the use of the symbol •[ in this context, particularly as the author has been sufficiently inconsistent as to use the more widely understood/•1 at least once (p. 134).

BOOK REVIEWS 241 The final chapter of 22 pages, deals with methods of determination of ammonia in Kjeldahl digests or in resulting distillates, and comprises a straight-forward review of such methods. The volume ends with 66 pp. of bibliography from a brief exa- mination this appears to be as comprehensive as would be hoped for such a mono- graph. Whilst clearly the larger laboratories, and also smaller ones using the method a great deal, will find such a volume almost a necessity for their libraries, its high price presumably associated with its American origin, will deter many smaller users from purchasing the book. M.J. GLOVER.