Further note on the course of the taste fibres / by A. Francis Dixon.

  • Dixon, A. Francis (Andrew Francis), 1868-1936.
Date:
1897
Catalogue details

Licence: Public Domain Mark

Credit: Further note on the course of the taste fibres / by A. Francis Dixon. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    there a distinct loss of taste at the root of the tongue or on the soft palate. As regards the tip and anterior two-thirds of the tongue, in three out of the six cases some taste sensation was re- tained after the fifth nerve roots were removed, although certain substances were either not tasted at all or their sensation was de- layed. In two cases taste sensation in this region was lost, one of these being that already noted as having no sense of taste on soft palate or root of tongue. In the sixth case the patient, after removal of the Gasserian ganglion on one side, tasted equally well on both sides. The patients thus present very different conditions as regards sensations of taste on the anterior part of the tongue after removal of the fifth nerve roots. The results of other authors which are detailed in Professor Krause’s work are found to vary in a similar manner. We may at least safely conclude, however, that for the posterior part of the tongue the taste fibres present in the glosso-pharyngeal nerve do not usually reach the brain by the fifth nerve roots through connections existing between the ninth and fifth nerves. This conclusion is supported by anatomical and embryological considerations. Since the operation of removing the fifth nerve roots often destroys taste sensation more or less on the anterior part of the tongue, it is fair to assume that in addition to the ninth nerve there is some other nerve of taste. Anatomical and embryological considerations point to the sensory part of the facial nerve as the path for these impulses. Professor Krause does not appear to recognise that the seventh nerve is in itself partly a sensory nerve, because he concludes that in those cases in which taste sensation is present on the anterior two-thirds of the tongue, after destruction of the fifth nerve, the impulses reach the brain through the ninth nerve, by means apparently of the communica- tions effected between that nerve and the geniculate ganglion (p. 89). In another place we find him quoting a case in which he removed the second division of the fifth nerve with negative results as regards taste, while a later removal of the Gasserian ganglion in the same woman caused complete loss of taste sensation, as supporting the idea that taste impulses from the anterior two-thirds of the tongue travel by the chorda tympani into the lesser superficial petrosal, and thus by the otic ganglion into the third division of the fifth nerve. The last observations le a) s great stress on, as he considers the conclusions based on them very sound. On the whole, however, reading his work care- tuily, he appears to believe that the course taken by the taste hidivlduals1 ^ antenor part of the tongue varies in different certamly seems rash to assume a variability in the course of the taste fibres for the anterior part of the tongue, while every- thing seems to prove that this is not so for those from the