The carotenoids are not only amongst the most widespread of the naturally occurring groups of pigments, but probably also have the most varied functions; witness their known roles in photokinetic responses of plants, in phototropic responses of fish and as vitamin A precursors in mammals and birds. Pigments with such wide distribution and such diverse functions are obviously of great interest to biological scientists with very different specializa- tions, especially as it is unlikely that the study of the functions of carotenoids is anywhere near complete. The primary aim of the present work...

des Plantes (Hermann, Paris), and in 1935 by Lederer's Les Carotenoides des Animaux (Hermann, Paris). Since then a survey such as the present one has not appeared. In order to present a full picture, much of the pre-1934 work has been reconsidered and, as far as is known, every important contribution which has appeared since that date has been discussed. Two peripheral aspects ofthe subject have, however, been omitted, namely (a) the qualita- tive and quantitative changes which the carotenoids of plant materials undergo in storage or during processing into food and (b) the carotene...