370 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (29) Maron, S. H., Kreiger, I. M., and Sisko, A. W., 5 e. ./lppL Phys., 25, 971 (1954). (30) Maron, S. H., and Belner, R. J., Ibid., 26, 1457 (1955). (31) McKee, S. A., and White, H. S., ./1STM Bull., No. 153, 90 (1948). (32) McKee, S. A., and White, H. S., 5 e. Rese,a, rch NBS. 46, 18 (1951). (33) Philippoff, W., "Viskositat der Kolloide, Ann Arfior, J. W. Edwards (1944), pp. 44-45. (34) Kreiger, I. M., and Maron, S. H., 5 e. -/lppL Phys., 25, 72 (1954). EXPERIMENTS ON MITOTIC FLARE-UP AND ACANTHOSIS* By Da. ROBERT Bau• University of Geneva Hospital, Geneva, Switzerland L'EXAMEN DE LA POVSS•E mitotique est fait sur la t&ine de cobaye male. On applique une goutte de la solution i tester, puis on injecte au cobaye de la colchicine. Cet alcaloide est un rkvklateur des cellules en division. On kvalue ensuite le nombre des mitoses sur la coupe histologique. Les oestroganes et les produits ayant un effet toxique primaire entre autre provoquent une telle pousske mitotique. Parmi 8 dkrivks du dinitro- chlorobenzane examinks de cette mamiare, les 4 produits connus comme eczkmatoganes provoquarent une forte pousske mitotique tandis que les 4 autres n'en donnarent pas. D'autres produits tels que tkrkbenthine, chrysarobine, cignoline, certains alcools et hydrocarbures, le gkraniol et le farnksol, etc., provoquent kgalement une pousske mitotique. L'examen du pouvoir acanthogane d'un produit est fait sur le fianc du cobaye. Apras avoir appliquk la substance, soit pure, soit diluke dans u'n excipient, pendant plusieurs jours, on prklave un kchantillon du fianc traitk et du fianc non trait& On mesure l'epaisseur de 1%piderme sur les coupes histologiques. On voit ainsi si l'kpiderme s'est kpaissi ou non sous l'infiuence du produit appliqu& Nous avons examink de cette maniare diffkrents onguents ainsi que route une skrie d'alcools et d'acides aliphatiques saturks et non saturks. Tandis que pour les alcools saturks (de C2 & Cls) on ne remarque pas d'effet acanthogane, les alcools avec une double liaison (Cll et C•s) montrent une forte action. Parmi les acides saturks on remarque un maximum avec l'acide laurique quant aux acides avec une double liaison, ils sont net- tement acanthoganes & partir de C•0 et cet effet augmente jusqu'& l'acide krucique (C20. * Risuml of Paper Presented at the August 2, 1957, Meeting, Geneva, Switzerland.

THE INTERFERENCE OF NONIONIC EMULSIFIERS WITH PRESERVATIVES WITH SPECIAL REFERENCES TO COSMETICS*,•' By M. G. DENAVARRE Cosmetic Laboratories, [nc., Div. Beauty Counselors, Inc., Detroit 7, Mich. NoN•oN•c emulsifiers have become widely used in cosmetics because of their over-all usefulness. With a trend toward the formulation of emulsions having a pH similar to the skin, nonionics became the emulsi- fiers of choice. Furthermore, they find use in high electrolyte content formulations, solutions and emulsions of perfume oils and as both water- in-oil and oil-in-water emulsifiers fbr all purposes. They are comparatively inert and nontoxic. This paper attempts to be a practical approach to the study of the inter- ference of nonionics with preservatives, since in commerce any apparent microbial growth with or without other manifestations of spoilage is a financial loss. In 1948 the spoilage of a commercial nonionic emulsion preserved with 0.15 per cent methyl p-hydroxybenzoate led to the present study. The solution to this problem seemed rather simple at first hand. But it was not. Indeed, it is not certain that a solution exists even now. For in 1950 the experimental work took a new twist with the publication of the Bolle and Mirimanoff paper entitled, "Antagonism Between Nonionic Detergents and Antiseptics." Preservatives are merely antiseptics, and while the publication just mentioned did report a very limited number of tests with Nipagin, a well-known p-hydroxybenzoate preservative, it raised a number of ques- tions with far reaching consequences. Basically, it had to be determined if antagonism between nonionics and all common preservatives did exist in fact. If so, to what degree did nonionics retard preservative action? Was the conflict limited to a particular class of preservative ? Which types of nonionics were involved? If the inactivation were widespread, how could it be overcome? The literature since 1950 contains a number of mentions of antiseptic * Based on paper given at Symposium on Antimicrobial Preservatives, Society of American Bacteriologists, April 29, 1957, Detroit, Mich, by permission. • Presented in Geneva, Switzerland, August 5, 1957. 371