THE METABOLISM OF STEROIDS BY CLADOSPORIUM HERB.4RUM 467 It is possible to evaluate the efficiency of preservatives by using nutrient medium seeded with the susceptible material and the preservative, or as our present studies tend to indicate, by direct examination of the cream seeded with vegetative organism. In a parallel study to the steroids, for instance, we were able to confirm the ineffectiveness of the hydroxy- benzoates used and demonstrate that these too were utilised as a substrate. (Received: 8th September 1967) REFERENCES (1) Private communication from Commonwealth Mycological Institute. (2) Fonken, G. S., Murray, H. C. and Reineke, L. M. J. Am. Chem. Soc. 82 5507 (1960). (3) Peterson, D. H., Eppstein, S. H., Meister, P. D., Murray, H. C., Leigh, H. M., Weintraub, A., and Reineke, L. M. J. Am. Chem. Soc. 75 5768 (1953). (4) U.S. Pat. 2,967,803. (5) U.S. Pat. 2,768,928. (6) U.S. Pat. 2,602,769.

j Soy. Cosrnetiv Chemists 19 469-484 (1968) ¸ 1958 Society of Cosmetic Chemists of Great Britain The dispersion of pigments into dry powder base: A comparison between three mechanical methods T. A. BROCK* Presented at the Symposium on "Processing and Manu- facturing", organised by the Society of Cosmetic Chemists of Great Britain, at Leamington, Warwicks. on 14th November 1967. 8yn0psls---The paper describes the method used to compare the efficiency of three systems of dispersing inorganic pigments into a white base. The instrumental method of colour measurement used is outlined, and the significance of the results obtained discussed. The effect of the various systems on the economics of coloured dry powder production is indicated. INTRODUCTION The work which forms the basis of this paper was put in hand as part of a programme to investigate the efficiency of the production of coloured dry powders. This led to a critical appraisal of the equipment and procedures which had been in use for many years for this process. At the time that this programme was instituted in the compounding department concerned, the laboratory was investigating the possible application of an abridged spectrophotometer/colorimeter to the problems of cosmetic shade matching. It was therefore decided to use the instrument to assess the degree of colour dispersion attained by the three methods under investigation, in addition to the normal visual assessments called for in our regular quality control procedures. The numerical data obtained were evaluated both on the basis *Formerly with Max Factor, Bournemouth, Hants. Now with Yardley of London Ltd., Basildon, Essex. 469