The results of cutting the seventh cranial nerve in Amiurus nebulosus (lesueur)

Abstract

HISTORICALThe study of the effects of nerve cutting, such as the classic experiments of Waller ('52), proved early in the history of physiology to be one of the most fruitful methods of investigation.Vintschgau und Honingschmied ('76) found that when they severed the glossopharyngeal nerve on one side of a dog's head, the taste buds on the corresponding side of the tongue disappeared, while those on the other side remained intact.This phenomenon was later investigated more thoroughly by Vintschgau ('80).According to his results, forty-eight hours after operation the so-called 'cover cells' became swollen and filled witch granules which stained light gray with osmic acid.The contour of the taste bud disappeared a few days later, and finally in place of the taste bud there came irregularly placed epithelial cells.Vintschgau thought he had evidence that the 'cover cells' metamorphosed into ordinary epithelial cells, but he was able to see only one cell actually undergoing this process.By the seventh day nearly all the taste buds had disappeared, though a few persisted for even a month after the operation.Drasch ('87) repeated this experiment with like result.Ranvier ('88) described in a foot-note in his "Trait6 Technique d'Histologie" the result of cutting the ninth nerve in the rabbit.Forty-eight hours following the operation profound modifications set in, which led to complete disappearance of the taste buds after forty days, But, unlike Vintschgau, he found that the sense