NUTRITIONAL DERMATOSES IN THE RAT

Abstract
The lesion of vitamin A deficiency has been defined by Wolbach and Howe1 as atrophy of many glands, arrest of growth, emaciation and replacement of many different single-layered epitheliums by stratified keratinizing epithelium. The process of the change from the cuboidal or columnar type of epithelium to the stratified type is known as keratinizing metaplasia, and it has been demonstrated numerous times in various epitheliums other than skin.2 There is no confusion regarding the primary histologic alterations and the resulting lesions of the eye, the paraocular glands and the respiratory, gastrointestinal and genitourinary systems. However, the question of the cutaneous lesion of vitamin A deficiency in the rat has been a matter of contention in many quarters, and it should be clarified. An analysis of the important early investigations of the cutaneous lesion of vitamin A deficiency in the rat explains some