Experimental endolymphatic hydrops in the rat.

In the rat, the epithelial lining of the endolymphatic duct and sac, and the contents of the sac, showed remarkable differences in comparison with these structures in the guinea pig and man. Obliteration of the endolymphatic duct resulted in endolymphatic hydrops of varying severity in 55% of the rats, after survival times varying from one to five months. The presence of a positive periodic acid-Schiff-stain for coagulum accumulating in the endolymphatic duct after prolonged saccus obliteration suggests active involvement of the endolymphatic duct in the migration of endolymph toward the endolymphatic sac.