VIII. An experimental investigation of the central motor innervation of the larynx

In the course of observations dealing with the physiology of the motor innervation of the larynx, the results of which were embodied in a paper recently presented by one of us (F. S.) to the Royal Society, it was shown that the central innervation of the larynx played a much more important rôle in the function of respiration than had previously been accorded to it. More especially it was shown that certain nervecentres were constantly at work in maintaining a reflex-tonus of the abductor muscles (posterior crico-arytænoids) indispensable for the mechanism of quiet respiration in Man. In 1880, 1881 and 1883 it had been shown by one of us (F. S.) that these same muscles (the abductors) were more liable to degenerative changes in cases of organic disease of the motor nerves of the larynx from the medulla oblongata downwards, and at the same time that functional disorders of the laryngeal motor apparatus almost exclusively affected their antagonists, the adductors. The explanation of all these different phenomena presented great difficulties, and, although light was thrown upon them in very various and unlooked-for ways, it soon became evident that neither clinical and pathological observations in Man alone, nor experiments upon the peripheral nerve mechanism of animals, would suffice to solve all the questions here involved.