In fact, we have to do with exaltation of sensibility simply, with sometimes pain; second, with delusion of sensation; and, third, with lost or diminished {62} sensation. For all practical purposes, therefore, we may adopt this arrangement, but should consider it as only provisional, as has been well observed by Schnitzler. These conditions are described under the terms hyperæsthesia, with or without pain; paræsthesia; anæsthesia. Hyperæsthesia. DEFINITION.--Exalted sensibility of the larynx, not necessarily associated with pain or other disorders of function. This condition is rare, but it is nevertheless met with. We sometimes find that the larynx is abnormally sensitive to touch or to an irritant, even though there is no marked inflammation. The symptoms and history justify the consideration of the condition apart. ETIOLOGY.--Predisposing causes are probably to be found in the general condition of the nervous system. Persons of a highly susceptible nervous organization are, other things being equal, more prone to this affection. Certain habits of life, such as confinement to the house or want of exercise in the open air, excessive use of the voice in singing, especially in unnatural keys or after unnatural methods, have seemed to me to predispose to the exaltation of the sensibility of the organ. It must be confessed, however, that so little is accurately known of the history of the disease that we are left in much doubt as to the rôle of these conditions in the production of the abnormal state. The exciting causes of hyperæsthesia of the larynx are the long-continued action of the predisposing causes--acute and chronic inflammation, mechanical and chemical irritants, etc. So far as my own experience goes, the use of the voice in an unnatural key, or perhaps rather the strain upon the parts by efforts to force the organ to perform the function of phonation in an abnormal manner, has more frequently been assigned by the patient as the cause than any other one thing. I have seen quite a number of singers who have by an effort of the muscles, apparently, produced an intensified irritability of the mucous surfaces. It is possible that in rare instances there may be an exalted activity of the receptive centres, and that the local trouble in the larynx is only a manifestation, in the distribution of the nerves, of the central disease. In such cases, however, the disorder should reach all the parts supplied by the pneumogastrics. Inflammation of the pharynx, soft palate, posterior nares, and perhaps of the structures of the ear, have an influence over the sensibility of the parts below, probably through the relations of the glosso-pharyngeal and other nerves to the laryngeal branches of the pneumogastrics. E. F. Ingals of Chicago has seen a case of laryngeal hyperæsthesia produced apparently by a varicose condition of the vessels about the base of the tongue. Frankel, Tornwaldt, Bayer, Schnitzler, A. H. Smith, Glasgow,