476 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS moderate exposure. The tests conducted in this study were designed to evaluate concentrated and dilute solutions under conditions of both severe and mild exposure. Table 5 presents the average reaction of three rabbits to repeated, pro- longed, applications to the uncovered intact skin of the ear. This tech- nique simulates exposure to uncovered skin which can be assumed to occur with many cosmetic preparations. Table 6 presents results of similar ex- posure under more rigorous conditions of close confinement to abraded as well as intact skin of the shaved rabbit belly. Such conditions could be encountered from spills or splashes on the clothing or shoes. The data reveal that four of the materials studied at 25 per cent concen- tration produced chemical burns upon single, prolonged contact, either when applied to the uncovered skin of the rabbit ear or when confined to the rabbit belly. Several materials possess indexes between 4 and 5.5, which indicates that they may cause burns upon repeated, prolonged contact. Abraded skin is particularly vulnerable to such exposure. The test mate- rials possessing indexes between 2 and 4 have relatively low toxicities in- sofar as skin irritating properties are concerned. Repeated, prolonged, confined contact with the rabbit belly over a period of fourteen days pro- duced no more than a very slight to slight erythema and even less irritation to the ear. Five of the materials at 25 per cent concentration fall into this class. When reduced to 1 per cent in water all of the test materials proved to be very low in skin irritating potential. Some produced no effect what- soever upon the ear at 5 per cent concentration and only a very slight effect at 25 per cent. The data indicate that of the materials tested those least likely to be skin irritants are the ethylene oxide adduct of nonylphenol and the sodium, magnesium and triethanolamine salts of dodecylated diphenyl ether di- sulfonate, the triethanolamine salt of the latter being the least irritating of all. SUMMA R Y The toxicological properties of several commercially available surfactants have been determined and compared from the viewpoints of acute oral tox- icity, eye effects and skin effects. Since the results show that there are wide differences on all counts be- tween the materials studied, the data presented should be helpful in the selection of surfactants for use in formulations where health and safety are of prime concern. The information given herein is presented in good faith, but no warranty is given nor is freedom from any patent owned by The Dow Chemical Company or by others, to be inferred.

CHEMICAL STRUCTURE AND ANTIMICROBIAL ACTIVITY OF BIS-PHENOLS II. Bactericidal Activity in the Presence of an Anionic Surfactant By GEORGE R. WALTER and WILLIAM S. GuMp* A PREVIOUS report by Gump and Walter cited the bacteriostatic and fungistatic properties of a series of bis-phenols (1). Numerous other workers have evaluated bis-phenols in general for microbiological activity (2). A review of the literature will indicate that the great majority of published investigations have been concerned with bacteriostatic or fungi- static activity. Several papers have appeared wherein the authors refer to the bactericidal activity of hexachlorophene (G-11©) the size of the inhibi- tion zones on agar plates is measured and taken as criterion of the bacteri- cidal effect (3, 4). Besides our own work (2, 5) with dichlorophene (G-4 ©) and hexachlorophene, the number of publications dealing with truly bactericidal action are few indeed (6, 7). In addition, bactericidal data have often been erroneously interpreted because of the highly bacteriostatic nature of the bis-phenols coupled with the omission of a neutralizer in the test procedures. Some reports, however, have appeared which depict bactericidal action where adequate precautions against bacteriostatic effects were taken (8). Several instances have been reported relating to an enhancement phe- nomenon between anionics and bis-phenols (9, 10). Preliminary work in our laboratories demonstrated that certain anionic surfactants of the alkylaryl sulfonate type will solubilize hexachlorophene and maintain bactericidal action. It was observed that bis-phenols other than hexa- chlorophene exhibited bactericidal properties when in the presence of an anionic surfactant, and a series of bis-phenols showing bacteriostatic activity, as previously reported (1), was selected and screened for possible bactericidal activity. Our concern was primarily that of detecting lethal action at low levels of the test compound. It was deemed desirable that the technique employed should measure any kill observed quantitatively, inasmuch as it was antici- pated that the magnitude and rate of kill would not be such that extinction * Sindar Corp., Delawanna, N.J. 477