PATHOLOGY.--So far as the pathology and morbid anatomy have been studied, there is no appreciable change of structure. This is true, of course, only of those cases which are not complicated. Whether the primary lesion is in the mucous membrane, denuding, pinching, or otherwise modifying the terminal portions of the nervous filaments, or whether there is an alteration of the conducting portion of the sensory nerves, or, in fine, whether there is some lesion of the receptive centres, it is impossible in most instances to say. It is probable, however, that in some cases the first morbid fact has been an alteration in the nerves themselves. The cases induced by unnatural methods of using the vocal organs are apparently of this character. The diagnosis, prognosis, and treatment will be considered in connection with Paræsthesia. Paræsthesia. Closely connected with hyperæsthesia of the larynx is a form of sensory delusion consisting of the impression that some foreign substance is lodged in the organ or that there is some alteration an the structure of the parts. This is known as paræsthesia. ETIOLOGY.--The first variety of sensory delusion depends on a primary injury to the parts. A bone or pin or some other foreign body, perhaps having lodged in the parts for a short time, has left a persistent impression upon the mucous surfaces. It is possible that in some instances there may have been no foreign body in the parts, as we have in many cases only the statement of the patient. Local inflammations, small in extent, may possibly have left the parts in a morbidly sensitive condition justifying on the part of the subject the hypothesis of a foreign body. The second variety of paræsthesia is the expression of some disturbance in {64} a distant part. It is usually hysterical in its character or a variety of hysteria associated with neurasthenia. It belongs to the same class of phenomena as the sensory delusions in other parts of the body. The globus hystericus is one of its forms. Thaon[5] says that hysteria may give rise to neuralgia as well as to other forms of hyperæsthesia of the larynx. It also, according to this author, produces that form of paræsthesia in which there is a sense of a bone or pin or some foreign substance in the larynx. The general condition of asthenia, and especially of neurasthenia, may be assigned as a predisposing cause. The local injury in the one case and the general hyperæsthetic condition in the other, with some determining fact, such as the mental impression or an apprehension of trouble in the larynx, constitute the exciting causes. [Footnote 5: _Proceedings of the International Congress of Laryngology_.]