420 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS necessarily mean they do not exist.* Dr. Riley (in my department) has been engaged in work on skin photosensitivity and has shown that these reactions are probably due to damage to skin lysosomes with the consequent liberation of lysosomal enzymes. If the skin is pretreated with lysosomal stabilizers, such as chlorpromazine, these reactions can be prevented. I think that further work along these lines with lysosome stabilizers will ultimately show that many cutaneous reactions are due to lysosome damage. Chloroquin is, I believe, a lysosome stabilizer, and it has been used clini- cally in dermatology for many years as protection against sunlight. At first it was thought to act by increasing the screening effect of the'keratin'layer. This is possible, but as it is a lysosomal stabilizer' it would be capable of protecting the skin because of this property. DR. I. M. GIBSON: You mentioned Phenergan as a lysosomal stabilizer. I believe it is an antihistamine- is there a long and complex series of reactions involved, or is this simple direct action? THE LECTURER: AS far as I know it is a simple direct action and is an effect of Phenergan in addition to its action as an antihistamine. Dr. Rees, a colleague of mine, has shown that the toxic effects of various liver poisons could be protected against by giving Phenergan and other compounds, such as quinine. He considered that they stabilized the outer cell membrane, and the endoplasmic reticulum. These actions, I think, are quite divorced from any antihistaminic effect. *Since the reading of this paper an article has been published by R. L. Ohlson, J. Invest Dermatol. 46, 431, (1966) in which he has demonstrated acid phosphatase activity to be concentrated within bound structures of human epidermal cells. He suggests that these struc- tures may be lysosomes.

J. Soc. Cosmetic Chemists 18 421-432 (1967) (c) 1967 Society of Cosmetic Chemists of Great Britain The toxicology of materials artificial colouring L. GOLBERG* Delivered at the Symposium on "Colour", organised by the Society of Cosmetic Chemists of Great Britain in Eastbourne, Sussex, on 27th April 1966. $•raol•aia--The toxicology of artificial colouring materials is discussed in relation to the many practical problems that arise in safety evaluation. The importance is stressed of adequate knowledge of chemical composition and reliable standardization of the specification of material to be tested. General analysis of metabolic changes undergone by colourings in the intestine, liver and blood of experimental animals is followed by consideration of systemic toxicity and carcinogenicity. Special attention is given to the question of turnour induction by subcutaneous injection. Other aspects, such as effects on reproduction and the foetus, and mutagenesis are touched upon. Finally the question of dose-effect relationship is briefly considered. INTRODUCTION The use in the title of the term "artificial" might suggest that there is something especially toxic about such materials in comparison with colourings of natural origin. The simple fact is, of course, that what we do know about the toxicology of colourings relates almost exclusively to those of synthetic origin while those derived from natural sources, however naturrein they may be, represent practically unknown territory from the standpoint of the toxicologist. Thus, while it is the object of this paper to discuss the various ways in which artificial colour- ings and their breakdown products or metabolites may exercise deleterious influences on the body, it should be emphasized that such knowledge constitutes the essentiM basis for the assessment of hazard and reliable evaluation of safety-in-use. It is left to the reader to decide whether the public is better protected when such fundamental information is available than when the safety of the material is taken on trust because "nature made it." *British Industrial Biological Research Association, Carshalton, Surrey. [Now at Albany Medical College, New York, U.S.A.] 49.1