It is the intention of the authors to study various aspects of nail research, including the biology and pathophysiology of the nail: 1. The continuation of the study of the histopathology of nail diseases correlating nail signs clinically seen with histopathologic changes. Studies have already been published on Psoriasis, Lichen Planus and studies will be published on Onychomycosis, Darier's and Onycholysis. 2. Studies utilizing autoradiographic techniques are being continued on the incorporation of tritiated glycine, thymidine and cystine into various portions of the nail organ to determine tissue and cell kinetics of each component in rat, monkey, and human nails. 3. Studies designed to clarify the role of P. aeruginosa, Trichophyton rubrum, T. mentagrophytes, Candida albicans, Cephalosporium acremonium, Fusarium oxysporum, Aspergillus terreus, Arthroderma quadrificum, Scopulariopsis brevicaulis and other fungi found in abnormal nails, continue utilizing C14 cystine labeled nail plate. 4. Studies designed to show influences of various sex hormones on the nails will be undertaken in monkeys. 5. Studies designed to elucidate etiologic agents in chronic paronychia will be done. 6. Electromicroscopic studies and tissue culture studies to corroborate C-type RNA particle nature of inclusion seen in epidermal giant cells occurring in nail bed of Darier's disease patients.