When the lesion upon which a paralysis of the muscles of the larynx depends is below the point at which the superior laryngeal nerves leave the {80} pneumogastrics, the paralysis is limited to the phonators and respirators. The muscular bands and fibres by which the glottis is constricted are, in part at least, still capable of being thrown into contraction. This condition of recurrent paralysis may be due to a disease of the nerve-trunks, tumor pressing upon the nerves, cicatricial tissue by which the nerves are compressed, aneurism of the arch of the aorta or right subclavian artery, disease of the apex of the lung, especially of the right side, pleuritic adhesions, or, in fact, any injury or lesion along the trunks of the recurrents or pneumogastrics. The paralysis may of course be partial or complete. The SYMPTOMS vary according to the extent of the muscular disability. In case of complete paralysis of one side there may be aphonia, but not dyspnoea. The glottis admits a sufficiency of air, but does not close so as to allow of the vibration of the cords. Where there is complete paralysis on one side only, the voice is not necessarily entirely suppressed, but it is changed in its quality; it becomes rough, weak, and in its use gives rise to great fatigue. In long-continued cases there is in part a compensation for the want of motion of one of the vocal bands. The muscles of the sound side act with increased vigor, so as to carry the sound cord at its posterior extremity beyond the median line. The result is, that the two cords are brought so near each other that phonation is possible. The arytenoid of the non-paralyzed side is drawn forward beyond its fellow. The cord upon the affected side is less tense than that on the healthy side. The vibrations are therefore not equal; the pitch is different; the voice is therefore unnatural, rattling, uncertain. As we proceed to discuss the lesions in individual muscles or sets of muscles we shall have occasion to refer to these etiological considerations, as well as to some of the symptoms noted with partial or complete loss of power of the whole group of muscles of the organ. Paralysis of the Constrictors. Complete paralysis of the muscles, by which the vestibule of the larynx is closed, is rare. The partial paralysis of these muscles is, however, by no means uncommon. As we have already endeavored to show, it is probable that the motor functions of the muscular fibres in the ary-epiglottic folds--the superior constrictors--are mixed. Probably both the superior and inferior laryngeal nerves are concerned in their movements. It is not, therefore, easy to group these disorders according to the nerves involved, as has been done by Von Ziemssen, Mackenzie, and others.