PSEUDOMONADS IN COSMETICS 807 (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) Bean, H. S., Heman-Ackeh, M., and Thomas, J., The activity of antibacterials in two- phase systems, Ibid., 16, 15-30 (1965). Rogoff, M. H., Chemistry of oxidation of polycyclic aromatic hydrocarbons by soil pseudomonads, J. Bacteriol., 8 t, 998-1004 (1962). Solari, A. A., Dato, A. A., Herrero, M. M., de Cremaschi, M. S., de Reid, M. I., Salgado, L. P., and Painceira, M. T., Use of a selective enrichment medium for the isolation of ?seudomonas aeruginosa from feces, J. Bacteriol., 84, 190 (1962). Hedrich, H. G., Carroll, N. T., Owen, H. P., and Pritchard D.J. Viability of selected microorganisms in hydrocarbon furls, Appl. Microbiol., 11,472-475 (1963). Traxler, R. W., Microbial degradation of asphalt, Biotechnol. Bioeng., 4,369-376 (1962). Durham, N. N., and McPherson, D. L., Influence of extraneous carbon sources on bio- synthesis de novo of bacterial enzymes, J. Bacteriol., 80, 7-13 (1960). Alford, J. A., and Pierce, D. A., Production of lipase by Pseudomonasfragi in a synthetic medium, Ibid., 86, 24-29 (1963). Sultzer, B. M., Oxidative activity of psychrophilic and mesophilic bacteria on saturated fatty acids, Ibid., 82,492-497 (1961). Bently, R., and Slechta, L., Oxidation of mono and disaccharides to aldonic acids by Pseudomonas species, Ibid., 79,346-355 (1960). Peterson, A. C., and Gunderson M. F., Some characteristics of proteolytic cnzymes for Pseudomonas fiuorescens, A ppl. Microbiol., 8, 98-104 (1960). Ingraham, J. L., and Stokes, J. L., Psychrophilic bacteria, Bacte•iol. Rev., 2 t, 97-108 (1959). Manowitz, M., Preservation of cosmetic emulsions, Developments in Industrial Micro- biology, 2, 65-91 (1961). Kohn, S. R., Gershenfdd, L., and Bart, M., The effectiveness of certain antibacterial agents in ophthalmic solutions against Pseudomonas aeruginosa, J. Pharm. 3ci., 52, 967-974 (1963). Tice, L. F., and Bart, M., Factors to be considered in the preservation of cosmetic emulsions, Y. Soc. Cosmetic Chemists, 9, 171-180 (1958). Wedderburn, D. L., Preservation of toilet preparations containing nonionics, Ibid., 9 210-228 (1958). Barr, M., and Tice, L. F., The preservation of aqueous preparations containing non- ionic surfactants I., J. Am. Pharm. Assoc. Sci. Ed., 46,442-445 (1957). Evans, W. P., The solubilization and inactivation of preservatives by nonionic deter* gents, J. Pharm. Pharmacol., 16,323-331 (1964). Noble, W. C., and Savin, J. A., Steroid cream contaminated with Pseudomonas aeruo ginosa, Lancet, 1,347-349 (1966). Kohn, S. R., Gershenfeld, L., and Barr, M., Antibacterial agents not presently employed as preservatives in ophthalmic preparations found effective against Pseudomonas aeru- ginosa, J. Pharm. Sciences, 52, 1126-1129 (1963). Bdoian, A., and Koski, T., Resistance of Pseudomonas to various chemical germicides, J. Assoc. Agr. Chem., 47, 804-807 (1964). Ayliffe, G. A. J., Lowbery, E. J. L., Hamilton, J. G., Small, J. M., Asheshov, R. A., and Parker, M. T., Hospital infection with Pseudomonas aeruginosa in neurosurgery, Lancet, 11,365-369 (1965).

J. Soc. Cosmetic Chemists, 18, 809-829 (Dec. 9, 1967) A Statistical Approach to Evaluation of Cutaneous Responses to Irritants the W. M. WOODIN( , B.Ch.E.* and D. L. OPDYKE, Ph.D.• Synopsis--This study was done to test the application of certain eom•non statistical experi- mental designs to the field of human patch testing where they do not appear to have been used previously, and to investigate certain variables affecting irritation test results. Sodium lauryl sulfate, a typical irritant of general interest, was used. Two experiments are de- scribed in which several factors thought to affect irritation results were tested these included irritant concentration, certain time factors, and types of patch used. Irritation was basically scored on a five-point scale. Results showed that experimental and subject-to-subject variation could be greatly reduced by adequate experimental design, that several factors of interest were influential in the system, and that the error of measurement (estimation by a judge scoring the patch sites) was much snmller than had been expected. One of the signif- icant effects of considerable interest was the finding that the degree of observable irritation was a function of the interval between removal of a patch and the time the site was scored. INTRODUCTION It is well known that the use of patch testing for the detection of primary irritation or sensitization of human skin to various substances, as usually practiced, is subject to severe limitations of numbers (1). For example, it may readily be shown by elementary probability cal- culations that the use of the usual patch testing techniques, even were several thousand subjects to be used, might easily fail to predict a serious proportion of reactors in the population. This problem has not been solved by the techniques to be described in this paper, but it is hoped that it may have been ameliorated. The * Carter Products Research, Carter-Wallace, Inc., Half Acre Road, Cranbury, N.J. 08512. t Revlon Research Center, Inc., 945 Zerega Avenue, Bronx, N.Y. 10473. 8O9