Report on the progress of human anatomy and physiology in the year 1844-5 / [Sir James Paget].

  • James Paget
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: Report on the progress of human anatomy and physiology in the year 1844-5 / [Sir James Paget]. Source: Wellcome Collection.

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    composed of motor fibres exclusively, he adduces experiments. In many in¬ stances he divided the trunk of the facial directly after its exit from the stylo¬ mastoid foramen, (at least two inches further back than Panizza did); and in every one, acute pain was produced both by the division and by the irritation of the central portion of the trunk. The experiment was performed on horses, asses, dogs, and a sheep ; and he shows reason for believing that the pain was not due to anastomoses of the fifth with the facial previous to its exit from the skull; though he admits that some of it might be due to the anastomosis of the auricular branch of the pneumogastric. In many other experiments he irritated the chorda tympani, (which he exposed through the posterior wall of the tympanum), and every time he did so the animal gave signs of pain. M. C. Bernard* has added four cases of paralysis of the facial nerve, attend¬ ed by impairment of taste, to those five cases which he published in 1843.f Dr. Guarini’s experiments, showing that this is the motor nerve of the lingua- lis muscle, were noticed in the Report for 1842-3. M. BernardJ showed the same by experiments at nearly the same time as Dr. Guarini; and Dr. Verga§ corroborated them somewhat later: so that this fact may be considered cer¬ tain. To prove the influence which the chorda tympani thus distributed in the lingualis muscle exercises upon the sense of taste, M. Bernard adduces these nine cases of disease of one of the facial nerves in men, and many experiments on animals. In all these, the taste of the corresponding side of the tongue was impaired; the flavour of quinine, citric acid, and other strong substances was very slowly and slightly perceived, while on the other side of the tongue the perception of them was instant and acute. He shows that this impairment is from the paralysis of the chorda tympani, by cases in which the cause of paralysis of the facial nerve being seated in front of the giving off of the chorda tympani, the taste was not impaired; and by experiments in which the facial being divided behind the part where the chorda tympani is given off, the sense was destroyed. By this last experiment, in which no injury could be done to any filaments of the Vidian that may join the facial, and by other experiments, which sliow|| that the chorda tympani is insensible, he makes it clear that the influence which the chorda tympani has on the sense of taste cannot be due to branches of the fifth nerve transmitted by the Vidian to the facial. Neither can the loss of taste be due to the dryness of the side of the tongue, for it is as moist as the other side. His own explanation is, that the papillae of the tongue are rendered incapable of the vermiform movement by which they absorb the sapid particles, and bring them into contact with the gustatory nerve [a notion at least as improbable as any that his facts disprove]. In none of these four cases by M. Bernard was there any deviation of the uvula. They may, therefore, seem to confirm the evidence from Dr. Hein’s^[ experiments that the facial does not send branches to the muscles of the palate or uvula. But it is not certain that in these cases the seat of the disease of the nerve was behind the connexion of the petrosal nerves with it; and, if it were not, the muscles of the palate might be unaffected, though all the others supplied by the facial were paralysed. Notwithstanding these cases, therefore, and although Valentin** also has failed to excite movements of the palate in either the horse, dog, cat, or rabbit, by irritating the trunk of the facial nerve, yet, on the whole, I think the evidence is in favour of the opinion that, at least in man, the facial nerve sends filaments through the great superfical petrosal * Archives Gen. de la Med., Decerabre, 1844. f Annales Medico-physiologiques, Mai, 1843. I In the Inaugural Thesis of M. Pomies, Paris, 1842. 5, Gazetta Medica di Milano, Giugnio 24, 1843. || According to Morganti, this is wrong; but the experiment is not essential to the conclusion. •]| See last Report, '** Lehrbuch der Physioiogie, ii, p. 673.