An experimental investigation into the functions of the eighth pair of nerves, or, The glosso-pharyngeal, pneumogastric, and spinal accessory / by John Reid.

  • John Reid
Date:
[1840?]
Catalogue details

Licence: Public Domain Mark

Credit: An experimental investigation into the functions of the eighth pair of nerves, or, The glosso-pharyngeal, pneumogastric, and spinal accessory / by John Reid. Source: Wellcome Collection.

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    1 find that Bischoff* liad examined the effect of irritating these nerves in the recently killed animal. And though he failed to observe the contractions of the crico-thyroid muscle, and the con¬ sequent shortening of the larynx, produced by irritation of the su¬ perior laryngeal nerve, and in place of this describes some sup¬ posed palpitation of the mucous membrane of the larynx, yet the other results obtained by him were similar to those we have de¬ scribed in Exp. XIX. We have now to see how far the views we have stated above, are supported by the subsequent experiments on living animals. The superior laryngeal nerve was cut on both sides in two dogs and one rabbit, and the animals readily swallowed both solids and fluids without exciting the slightest cough or the least difficulty of breathing. The lungs were carefully examined after death, and none of the food taken could be detected in the air-passages. In several animals the superior laryngeals were first cut, and the inferior laryngeals immediately afterwards, and it was ascertained that the previous division of the su¬ perior laryngeals did not prevent the difficult breathing and symptoms of suffocation, which not unfrequently follow the division of the inferior laryngeal nerves, particularly in young animals. To procure still more positive assurance of the effect of section of the different laryngeal nerves upon the movements of the muscles attached to the arytenoid cartilages, the following experiments were performed. Exp. XX. All the four laryngeal nerves were exposed in a full-grown cat. The larynx was then dissected out by cutting between the hyoid bone, and thyroid cartilage, and drawn for¬ wards so as to expose the glottis without disturbing the nerves. When the glottis came into view, the arytenoid cartilages were observed to be drawn backwards and outwards during inspiration, and to approximate considerably during expiration. The extent of these movements of the muscles of the glottis was in propor¬ tion to the extent of the other respiratory movements. When the animal was quiet and breathing less forcibly, the movements were slight.- While uttering a cry, the sides of the superior aperture of the glottis were closely approximated, and were thrown into vibratory motion. While struggling violently, the superior aper¬ ture of the glottis appeared completely closed. A small opening was made into the trachea, and a silver probe passed upwards. This appeared to excite little if any uneasiness, until it arrived at the larynx. As soon as it entered the larynx it was instantly follow¬ ed by close approximation of the sides of the superior aperture of the glottis, violent cough, and evident uneasiness. The same ef-
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