The purpose of this paper is to present observations on the phonatory mechanism of the larynx revealing a close analogy with the phonetic mechanism of air column instruments of the cornet type. These observations evidently have an important bearing on those prevalent diseases of the larynx that are the result of vocal abuse. Myasthenia laryngis is a name applied by my co-author and me1to a morbid entity characterized by asthenia of the phonatory musculature of the larynx, especially the powerful overworked thyroarytenoideus muscles. It differs clinically from the ordinary fatigue of a muscle in that there is no tendency to prompt recuperation by rest and in that exercise does not strengthen the weakened muscle. It is a distinct morbid entity which has no connection whatever with myasthenia gravis. In most of the textbooks laryngeal muscular disability is not mentioned, and in none is a distinction made between mucosal chronic