ROLE OF COSMETIC SCIENTIST IN PROTECTION OF PUBLIC HEALTH 279 pose any significant health problems, we have declared them guilty based on animal test evidence. I am a great believe• in the scientific way of life. I would not think of marketing a cosmetic product without carrying out many tests, including animal tests. They are a very important part of any medical screening program. I have lived long enough to know, however, that the extrap- olation of any animal test results to human experience is a difficult exercise. It becomes a reckless exercise, in my judgement, when these extrapolations fly in the face of human experience. As Dr. Jonathan L. Hartwell, (4) of the National Cancer Institute, in the Introduction to his "Survey of Compounds Which Have Been Tested for Carcinogenic Activity" states: "... there are pronounced differences in the response of different (animal) species to the action of compounds carcinogenic in the case of the mouse" "... some compounds which were negative in the mouse can induce tumors in other species . . ." "... in the mouse itself, it is abundantly evident that different tissues r,espond differently to the same compound." ' . . . in the monkey, none of the powerful carcinogens has been shown to produce tumors." In view of these basic species problems in view of such known influences as dosage (carcinogenic effects in animals can be lost by using too much as well as too little), mode of administration, the vehicle used, the sex, strain and age of the animal, the diet--I can only conclude that we have a long way to go in the development of animal tests that will predict the suscepti- bility of man to particular carcinogens and, indeed, his susceptibility to many far less complicated medical afflictions. Cancer has become the medical scare word of our day. It conjures up in the lay mind a terrible fear of a dread disease. The irresponsible use of this word can cause legislative panic buttons to be pressed, buttons that will put the food, drug and cosmetic industries in scientific shackles into the indefinite future. It is the scientist's responsibility to make clear the limitations of his scientific methods, the methods the legislators would use as a basis for interpreting proposed public health legislation. We should admit that we cannot yet deliver the scientific guides needed for such legislation. Above all, we should admit that no tests conceived to date, or those about to be in the foreseeable future, will ever be anything but a second best substitute for human experience. In spite of the "coincidence factor," in spite of' the limitations of his methods, in spite of the unfair charge against his product, in spite of bad laws--but hopefully, with the support of good ones--the cosmetic scientist, along with his counterparts in Foods, Drugs, and Government will: 1. Continue to improve the contributions of cosmetics to human welfare.

280 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 2. Continue to insist on adequate testing of his products before they are marketed. 3. Admit the limitations of his testing methods and strive to improve them. 4. Continue to base his conclusions on scientific facts, not speculations. 5. In connection with all issues of major social importance, maintain his perspective on the value of human experience as it relates to the interpretation of scientific evidence. All these things are his obligations in his role as a scientist, as a protector of the public health, and as a member of human society. REFERENCES (1) Wax, Murray, .4m. •. Sociology, 62, No. 6,588 (1957). (2) Isaiah, 3: 24. (3) Macdonald, Eleanor, •. Soc. Cosmetic Chemists, 10, 246 (1959). (4) Hartwell, X., Pub. HeaM, Serv. Pub. No. 149, 2nd Ed. (1951). EFFECT OF VEHICLE COMPONENTS ON THE ABSORPTION CHARACTERISTICS OF SUN SCREEN COMPOUNDS By SIDNEY RIEGELMAN* and RICHARD P. PENNA Presented May 12, 1960, New York City THERE ^RE many physical, chemical and biological factors which must be considered in the formulation of a suntan cosmetic product. Cer- tainly none is more important than the selection of an active sun screen compound. However, this selection cannot be properly made solely on the basis of the information contained in the manufacturer's technical brochure. While this information may be accurate, it does not consider the effects of the vehicle components on the ultraviolet absorption characteristics of the compound. This paper will attempt to clarify some of these interac- tions and point to their significance in the formulation of a suntan prepara- tion. The region of the sunlight which a compound must absorb in order to be an effective sun screen is dependent on the intensity and wavelength of the solar radiation and the body's erythemic response to the light. In- significant amounts of the solar radiation reach the earth's surface below 290 millimicrons (m/•) (1, 2). The shorter wavelengths are screened out by the atmosphere. On the other hand, studies (3, 4) on the erythema pro- duced by ultraviolet light on untanned human skin indicate a maximal erythemagenic effect at 254 m/• and at 287 m•, separated by a minimum at 280 mu. Only the second maximum is within the solar radiation region. * Associate Professor of Pharmacy and Pharmaceutical Chemistry. University of California School of Pharmacy, Medical Center, San Francisco 22, Calif.