The conversion of many simple epithelia into the stratified cornified variety is a constant and characteristic sequel of a dietary deficiency in vitamin A. This change involves a proliferation of focally situated basal cells, which replace the distinctive epithelium of the affected region (Wolbach and Howe, '25 b) ; hence, the metaplastic tissue represents a new growth rather than a transformaton of the original epithelium. No observations have been reported upon the innervation of this structure, despite extensive study of the condition of the nervous system in vitamin A deficiency. Such information is needed jn order to characterize more completely the metaplastic epithelium.I n the present investigation, designed to determine the presence or absence of nerves in the metaplastic layer, structures which by their arrangement and staining reactions appear to be nerve fibers have been found. Their description is offered as a contribution to the basic knowledge of the histology of vitamin , 4 deficiency.
MA'I'ERIALS AND METHODSThe following observations were made upon silver impregnated tissues from nine male albino rats of the TYistar strain, which had been placed at weaning upon a diet low in vitamin A.This consisted of a mixture of 18% unextracted casein, 50%
223