and "Lichtphotismen" (aural and ocular hallucinations) are as yet of no clinical value.

The occurrence of blepharospasm with spasm of the stapedius muscle is to be explained as a reflex irritation due to the fact that both the stapedius muscle 1 and the orbicularis palpebrarum derive their innervation from the facial

nerve.

1 Gottstein, "Arch. f. Ohr.," XVI, p. 61.

THE upper air-passages are very much exposed to local injury during intoxications, both when the poison is contained in the air and thus comes into immediate contact with the mucous membrane of the nose, the pharnyx, and larynx, and when it is ingested in the form of a fluid or solid, and during its passage through the pharynx inflicts direct injury on that structure and on the upper margin of the larynx. From this point the poison may make its way into the interior of the larynx and set up an extensive morbid process. The ear escapes, as a rule, unless the tubes are involved in hypertrophic conditions of the postnasal space; hence, the number of substances capable of exerting any influence on the ear when taken by the mouth is very limited.

The most frequent symptoms produced by the great majority of organic and inorganic chemic bodies by direct irritation of the mucous membrane of the upper air-passages are hyperemia and sensory irritative phenomena, such as sneezing and coughing.

Their recognition presents no difficulty, as the cause of the intoxication can usually be ascertained, and the clinical picture presents no special characteristics for the individual kinds of intoxications, so that it is not worth while to enumerate all the various acids, alkalies, ethereal oils, etc., in this place.

Another group of symptoms which it is customary to refer to the action of various poisons can not be accepted as toxic phenomena without a reservation. Among these we have aphonia, hoarseness, and tinnitus aurium. The former is due to "adynamia, when the constitutional effect of the poison has so debilitated the entire organism that the phonetic function shares in the impairment of all the other functions, especially those of the central nervous system" (Stuffer 1 on "Toxic Aphonia"). In the literature of alkaloid poisoning we find in particular nervous disturbances

1" Arch. f. Laryng.," vol. VI.

of speech mentioned along with these adynamic phenomena, so that mistakes are very apt to be made in interpreting the findings.

The same applies to the auditory disturbances, which are usually given as tinnitus aurium. When we consider the manifold causes that may give rise to this phenomenon ; how frequently it is due to circulatory disturbances, which play so important a rôle among the toxic effects of many poisons; and that tinnitus aurium, and even hallucinations, often occur after the exhibition of stimulant remedies, we realize how easy it is to refer symptoms which really originate outside of the ear to a direct toxic effect of the poison on the ear itself.

We shall, therefore, mention only those substances which produce marked clinical disturbances clearly due to the constitutional effect of the poison, leaving out all the symptoms of a vague and indefinite character.

Acids and alkalies exert a direct caustic effect on the mucous membranes that manifests itself in various ways. The effect of acids is chiefly that of a cauterizing agent, causing constriction of the tissues and the formation of crusts, that is to say, the effect is more superficial and is localized in the region where it is applied,-whereas alkalies tend to dissolve the tissues and to produce deep destruction involving the entire surface of the mucous membrane and not confined to the area of contact. In both cases the affected part becomes surrounded by an area of marked inflammation and swelling. As the ingestion of liquid poisons is always accompanied with the cauterization of the pharynx and of the entrance to the larynx, —that is, of the epiglottis and the aryepiglottic folds,-the edema which follows may be very extensive, and the patient's life is endangered more by stenosis of the larynx than by the toxic effect of the substance itself.

The manner of healing and cicatrization similarly varies in accordance with this difference in the effects of acids and alkalies; in the former the resulting scars are smooth and superficial, while in the latter we have deep cicatricial contractions, and particularly the formation of cicatricial adhesions uniting the upper margin of the larynx with the deeper portions of the pharyngeal wall.

The commonest examples of these two kinds of intoxication are poisoning with sulphuric, hydrochloric, and nitric

acids on the one hand, and poisoning with potassium or sodium hydrate and ammonia on the other hand. That chlorid of zinc is capable of producing the same kind of destruction of the mucous membranes as an acid is shown by a case of v. Jaksch's 1, in which, after the drinking of a solution of chlorid of zinc and hydrochloric acid, such as is used in soldering (68 gm. of zinc chlorid and 3.5 gm. of hydrochloric acid to 100 c.c.), laryngeal stenosis occurred which necessitated tracheotomy. Among the intoxications by inorganic acids we must mention particularly chromic acid poisoning, as this substance is a favorite cauterizing agent in rhinologic practice. Acute chromic acid poisoning may follow the use of only a few centigrams, as in cauterization of the pharynx, and leads to a general intoxication in addition to the local symptoms; while, on the other hand, the chronic form of poisoning, which occasionally occurs in employees in chromic acid factories, produces deep-seated alterations of the mucous membranes. The inhalation of chromic acid in the form of dust at first leads to an inflammation of the nasal mucous membrane, which is soon followed by arrosions on the septum and on the anterior extremities of the turbinate bones, constantly accompanied by epistaxis. Ulceration also takes place in regions to which the particles of dust may be carried by the inspiratory air that is, the tonsils, the uvula, and the posterior pharyngeal wall. According to Seifert, 2 purulent inflammation of the tympanic cavity may also occur by extension through the Eustachian tubes.

The internal administration of the iodids, especially potassium iodid, is sometimes followed by alarming symptoms in the upper air-passages. It is well known that the exhibition of iodin is always accompanied by a slight swelling, redness, and desquamation of the mucous membranes, manifesting themselves in more or less marked coryza, lacrimation, pharyngitis, and laryngitis. But, in addition, the literature contains a number of intoxications following the use of potassium iodid which led to alarming symptoms, and in a few cases even necessitated tracheotomy. The symptom referred to is edema of the larynx. It has been observed in every part of the larynx-on the lateral wall, about the entrance, on one side of the larynx only, or on

1 Nothnagel's "Spec. Path. u. Therap.," vol. I.

2 Die Gewerbekrankheiten der Nase," etc., Fischer, Jena, 1895.

both sides in the subglottic region. Our knowledge of its cause and of its mode of origin is very meager. The intoxication does not appear necessarily to follow large doses of the drug, as cases have been reported in which a short course of treatment with small doses produced an intoxication (Rosenberg). In two cases reported by Schmiegelow 1 in which tracheotomy had to be performed, edema occurred after the administration of three teaspoonfuls of a 5% solution taken morning and evening in one case, and in the other case after only three tablespoonfuls of the same solution had been taken three times a day for several days. The cases in which the intoxication occurred after withdrawal of the drug (Heymann), or after it had been used for several weeks, must be considered exceptional, for we know that, as a rule, the mucous membrane becomes accustomed to the drug after a few days of catarrh; and, even in those cases in which edema of the larynx had occurred after a few days' use, the drug was subsequently very well borne when it was given in more conservative doses. The manner in which the intoxication occurs is as little known as its cause; it is remarkable how seldom grave toxic appearances are seen when we consider the enormous number of cases which are constantly treated with potassium iodid. Rosenberg believes that the occurrence of intoxication depends on the presence of glands; Avellis, arguing from an interesting case of unilateral paralysis of the recurrent nerve in which the administration of potassium iodid was followed by edema of the larynx on the unaffected half of the larynx only, suggests that iodid poisoning takes place by way of the nerves, like the angioneuritic edema of Strübing; while G. Lewin, in the face of antagonistic observations reported by Rosenberg and others, assumes that iodid edema depends on syphilitic disease, on the ground that a syphilitic ulcer reacts more intensely to iodin.

The aural symptoms observed after the use of potassium iodid consist in tinnitus aurium associated with difficult and double hearing. The first two phenomena occur in association with catarrh of the pharyngeal mucous membrane, which has led to acute catarrh of the tubes and its consequences; but it seems to me we may also assume that the

"Arch. f. Laryng.," vol. I.