30 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Me. D. W. PoxoN: Is there any relationship between surface activity and anti- bacterial activity? THE L•CTUR•R : We are not quite sure how the molecules are orientated at the interface, but we shall assume that the polar portion of the molecule is in the water, and the non-polar is in the oil. They will only be measurable in 2kngstroms whereas your cell is going to be microns in diameter. The organism is going to project into the aqueous phase very much further than the molecules, and it would seem that possibly only a portion of the cell surface is in contact with the higher concentration of bactericide or preservative. It is possible and, indeed very likely, that absorption of preservative molecules does also occur at the cell-water interface.

j. Soc. Cosmetic Chemists 16 31-38 (1965) ¸ 1965 Society of Cosmetic Chemists of Great Britain The Behaviour of Lanolin Derivatives in Pressurized Formulations II A. HERZKA* Presented at 3rd IFSCC Congress, New York, June 1964 Synopsis--The solubility of ten Golden Dawn lanolin derivatives in seven different pro- pellant/solvent systems, stored for six weeks at 0øC and 20øC, is described. The results indicate (1) that the solubility of four derivatives decreases on storage, (2) that the solubility of one derivative increases on storage, (3) that the solvent power of six of the propellant systems decreases on storage, and (4) that storage at 0øC does not materially affect the solubility of eight of the tested products. INTRODUCTION Having established the solubility and spray performance of ten lanolin derivatives in nine different propellant and propellant alcohol systems (1), further experiments were carried out with propellant/liquid paraffin systems, and with propellant/aqueous alcohol systems. The per- formance of these various compounds in a butane/aqueous alcohol system was also tested. The tests were carried out at 0øC and 20øC as previously (1). The following Golden Dawn products were tested' i. Anhydrous lanolin, B.P. ii. Wool alcohols, B.P. iii. Liquid lanolin "A.C.E." iv. Alcohol soluble lanolin. v. Liquid lanolin "50 Super." vi. Liquid lanolin "I.S.O." *Independent Consultant, London. 31