Experimental destruction of vestibular labyrinthine epithelia of the guinea pig with cryosurgery indicates that, with three minutes of treatment with −180 C (−292 F) and the cryoprobe applied at a precooled state, there is virtually no damage visible with light microscopy. However, with electron microscopy, regular signs of impaired metabolism are observed a few hours after treatment due to destroyed intramitochondrial membranes and formation of vacuoles in the cytoplasm. With the cryoprobe applied at room temperature and slowly cooled down to −180 C (−292 F), there is after 2½ hours a marked disintegration of the epithelial lining, presumably due to complete blocking of the cellular metabolism and cracking of the cytoplasm into fragments by ice crystal formation. It was possible with cryosurgery to experimentally produce a selective destruction of semicircular canal cristae with utricle, saccule, and cochlea remaining intact.