“…These changes included decreased keratinization, mucoid metaplasia, epithelial hyperplasia, disorientation of the basal layer, and increased mitoses (Bern et al, 1955;J ackson and F e l l , 1963; L a w r en c e and Ber n , 1958 and1960;R eiss and C am pbell, 1954;Rothberg , 1967).…”