branches or fibrils, or to disease of the muscles themselves. SYMPTOMS.--These are at first so slight that the trouble is usually not recognized till it has reached such a stage that the act of inspiration is either attended with fatigue or there is stridor which annoys the patient or alarms his friends. Soon afterward there begins to be a dyspnoea, a difficulty in breathing, especially during any active exertion and during sleep. The voice in the mean time remains normal. Expiration is free. The general health is usually undisturbed. There may be a catarrhal affection of the mucous surfaces, but if so it is quite accidental. Spasm supervenes. There is at times great difficulty of breathing, and, finally, the effort becomes so great that the patient becomes alarmed. Upon examination with the laryngoscope the vocal cords are seen in close proximity to each other even during the inspiratory effort. In fact, they are, by the pressure of the air upon their upper surfaces, brought closer together during inspiration than during expiration. They seem to act as valves which are closed by the weight of the atmosphere upon their wide, flat upper surfaces, pressing them against each other. Hence the inspiratory stridor and dyspnoea. The act of expiration is a passive one in health, and in this condition the air is easily forced out by pressing the cords away. The order of the movements of the cords is therefore changed--in the normal condition wide in inspiration, narrow in expiration; in this disease narrow in inspiration, and while not wide, at least wider, in expiration than in inspiration. In other respects the parts are normal. There is nothing to suggest the trouble except the closure of the glottis during inspiration. The course and duration of the disease are in a large majority of cases chronic. Once established, it tends to persist. The cases of diphtheritic origin should be excepted from this statement. In those forms in which the trouble is entirely in the muscles of the part life may, so far as we know, be continued indefinitely. Where the trouble is central it is probable that the cause has a tendency to involve other parts of the brain, and in this way to lead to other, and possibly dangerous, complications. Of this, however, we know but little. The paralysis is not directly the cause of death, except as it closes the glottis. The dangers are therefore mechanical. When the patient has once been placed in a condition of safety by the operation of tracheotomy the local paralysis no longer endangers life.