The cause of the sudden disaster to the voice which I have described is not far to seek. The cold has caused over-stimulation of the mucous membrane of the larynx, and a consequent loss of voice. This cold begins in the head, and on the third day, perhaps before, it has attacked the larynx. Why? Because the mucous membrane has become so swollen that the nasal passages are obstructed and the mucous membrane of the larynx has to perform a double function, that of heating the air as it is brought to the lungs in the process of respiration, as well as carrying out its own obligation to the scheme of nature. By a strange coincidence, this membrane of the larynx is supplied with sensation by the same nerve that conveys motion to one of its tensor muscles. This is the superior laryngeal nerve. By the thickening of the mucous membrane, all the intrinsic muscles of the larynx are interfered with, and, consequently, total extinction of the voice follows swiftly upon excessive inflammation. There you have it in a nutshell. The mucous membrane of the larynx and the bronchial tubes, to enlarge upon its duty for a moment, is endowed with very fine, hair-like processes called cilia, whose action is to waft secretions from the interior of the lungs outward. Hence the danger of promiscuous spraying with all sorts of everyday nostrums, or of anything which may interfere with the activity of these minute bodies or the media in which they operate. This intimate relation of nerve and muscle and mucous membrane is best illustrated by the sneeze. The explanation of this is an over-stimulation of a part of the mucous membrane of the nose called the Schneiderian membrane. If we analyze the sneeze, we find that it simply consists of a spasm of the pharynx, larynx and diaphragm through the reflex action of this membrane. The over-stimulation of the membrane, in the case of the singer especially, may generally be set down to an incipient cold; but any inflammation of this part of the mucous membrane of the nose alone may give rise in reflex action to vocal disability. There are some peculiarly interesting isolated instances of disturbance of the vocal mechanism, which are unique in that, while apparently harmless and uninteresting from the standpoint of even the specialist, they have, on occasions, developed most alarming influence over the voice. They have no precedent; experience alone can determine their influence for evil. They are not a matter of record, they are simply études, interesting studies in the bypaths of vocal hygiene, and must be dealt with as they appear. An exceptional example was one wherein the voice of the singer was perfectly even except as to the G sharp in the medium, which was entirely wanting--as though it had never existed.