NAIL FORMATION AND SOME NAIL DISORDERS 413 intermediate keratin one might say? Histochemical studies show that this material from the nail bed is, in fact, different from the true nail keratin, but it is arguable. Is everything that looks like a nail, a nail? I think this argument has not been really solved. MR. C. J. KIRK: Could you tell me whether fat solvents as such have any peculiar effect on nails? Ta• L•CTUR•R: Apart from the general effect on the epidermis, none that I know of.

J. Soc. Cosmet. Chem. 23 415-426 (1972) ¸ 1972 Society of Cosmetic Chemists of Great Britain The clinical significance of the presence of micro-organisms in pharmaceutical and cosmetic preparations M. T. PARKER* Presented on 29th September 1971 in London, at the Symposium on 'Microbial control', organized by the Pharmaceutical Society of Great Britain and the Society of Cosmetic Chemists of Great Britain. Synopsis--Contaminated PHARMACEUTICAL preparations may cause DISEASE when injected into tissue, implanted into wounds or normally sterile areas of the body such as the bladder or the lower respiratory tract, or, in certain circumstances, when deposited on the skin or administered orally. Of the organisms found in pharmaceutical preparations, only the salmonellae cause disease when administered to healthy persons by a 'natural' route. The rest are 'conditional' pathogens, which cause disease in healthy persons other than newborn infants only when injected into the tissues or implanted directly into a sterile area of the body but in certain classes of susceptible persons it is sufficient to deposit the organism on the skin or to administer it orally. These classes include patients with severe pre-existing disease, patients with lowered resistance due to therapy, and infants during the first few days of life. Most of the ORGANISMS of clinical significance in pharmaceutical preparations aro 'free-living' types of GRAM-NEGATIVE BACILLI, and belong to the klebsiella, enterobacter, serratia, pseudomonas and flavobacterium groups. They have simple nutritive characters and can multiply at ambient temperature in fluids apparently devoid of organic matter. Many of them have a remarkable ability to survive and even to multiply in the presence of commonly used DISINFECTANT and BACTERIOSTATIC agents. *Cross-Infection Reference Laboratory, Central Public Health Laboratory, London, NW9 5HT. 415