THE SKIN TESTING OF NEW COSMETICS 321 tant part. Rigid specifications should be set up and quality control maintained on container and valve material. Stability testing of aerosols al- though perhaps a little more compli- cated and painstaking than the stability testing of other cosmetic preparations is still a matter of being practical. From the above discussion you might probably say to yourself, "It takes a long time, we cannot wait." My sincere answer to that attitude is that an aerosol product cannot be placed on the market under any other conditions. There is no compromise for running the stability and control tests on low- pressure aerosols. THE SKIN TESTING OF NEW COSMETICS* By Louts SCIW^P. TZ, M.D. trashington 6, D.C. THE CLOSED patch test was devised many years ago by Jadas- sohn as a means of finding the irri- tant in cases of contact dermatitis. It is a diagnostic procedure. The skin testing of new cosmetics is comparatively recent and is still in the stage of development. The prophetic patch test was devised about 14 years ago while I was in the U.S. Public Health Service to test the possible irritant properties of the then new synthetic fiber now known as nylon. It came about as follows: before nylon was placed on the market, the manufacturers asked the U.S. Public Health Service to devise a test which may show whether gar- ments made of the new synthetic fabric would be safe to wear. The result of this request was the pro- phetic patch test. * Presented at the May 18, 1951, Meeting, New York City. The original prophetic patch test consisted in placing a half-inch square piece ofunprocessed nylon on the skin of 200 subjects, covering it with a piece of cellophane 1 inch square and sealing this on the skin with a piece of adhesive plaster 3 inches square. A piece of un- bleached unprocessed cotton fabric of similar size was fastened on the skin of the opposite side of the body to act as a control. The patches remained on for forty-eight hours, then removed and the reactions read and recorded. The sites of the patches were ex- amined for 3 consecutive days for late reactions. Ten days after the last reading the patch testing was repeated on the same 200 subjects and on approximately the same skin areas. The patches were removed after forty-eight hours and the sites examined for signs of reactions for three consecutive days. The second

THE SKIN TESTING OF NEW COSMETICS 321 tant part. Rigid specifications should be set up and quality control maintained on container and valve material. Stability testing of aerosols al- though perhaps a little more compli- cated and painstaking than the stability testing of other cosmetic preparations is still a matter of being practical. From the above discussion you might probably say to yourself, "It takes a long time, we cannot wait." My sincere answer to that attitude is that an aerosol product cannot be placed on the market under any other conditions. There is no compromise for running the stability and control tests on low- pressure aerosols. THE SKIN TESTING OF NEW COSMETICS* By Louts SCIW^P. TZ, M.D. trashington 6, D.C. THE CLOSED patch test was devised many years ago by Jadas- sohn as a means of finding the irri- tant in cases of contact dermatitis. It is a diagnostic procedure. The skin testing of new cosmetics is comparatively recent and is still in the stage of development. The prophetic patch test was devised about 14 years ago while I was in the U.S. Public Health Service to test the possible irritant properties of the then new synthetic fiber now known as nylon. It came about as follows: before nylon was placed on the market, the manufacturers asked the U.S. Public Health Service to devise a test which may show whether gar- ments made of the new synthetic fabric would be safe to wear. The result of this request was the pro- phetic patch test. * Presented at the May 18, 1951, Meeting, New York City. The original prophetic patch test consisted in placing a half-inch square piece ofunprocessed nylon on the skin of 200 subjects, covering it with a piece of cellophane 1 inch square and sealing this on the skin with a piece of adhesive plaster 3 inches square. A piece of un- bleached unprocessed cotton fabric of similar size was fastened on the skin of the opposite side of the body to act as a control. The patches remained on for forty-eight hours, then removed and the reactions read and recorded. The sites of the patches were ex- amined for 3 consecutive days for late reactions. Ten days after the last reading the patch testing was repeated on the same 200 subjects and on approximately the same skin areas. The patches were removed after forty-eight hours and the sites examined for signs of reactions for three consecutive days. The second