We have to deal, then, with three different manifestations of the diphtheritic process: first, with a membrane lying on the mucous membrane, and removable without causing much injury to the epithelium or any to the basement membrane; such membranes were given by some the name of croupous deposits; secondly, with a membrane implicating the epithelium and upper layers of the mucous membrane; to this the title of diphtheritic membrane has been given by preference; thirdly, with a whitish or grayish infiltration of the surface and the deeper tissue, which, if abundant, may give rise to a necrotic destruction of the tissue.

The severity of the disease does not always depend on the predominance of one of these three forms, for any of them may accompany a mild or a severe attack. By a severe attack we understand one attended with chills, temperatures as high as 105° and 107° F., and marked nervous symptoms, such as vomiting and convulsions. It is characteristic of such cases that when the membrane is accidentally or forcibly removed it is speedily reproduced; the lymphatic system, in addition, takes an active part in the process. The neighboring glands become swollen; the periglandular tissue does likewise, so that the circumference of the neck becomes enormous, and the space between the lower jaw and the clavicle appears one immense tumefaction. These are the cases in which, as a rule, loss of strength and general debility speedily ensue, and death occurs from exhaustion. The membrane in cases of this description frequently undergoes changes in appearance; under the influence of the atmosphere and of foreign substances, and by admixture of blood, its color becomes yellowish or brownish. The odor of the membrane and surrounding parts becomes sweetish and musty, and occasionally so fetid that it contaminates the atmosphere of the room, and the air in its transit through the nose and over the pharynx becomes by inhalation dangerous to the patient. His throat becomes more swollen, his respiration loud; he keeps his mouth open constantly, has an indifferent expression; the saliva dribbles continually, the color of the skin is sallow and livid, the appetite very poor, and pulse both frequent and small. When the symptoms are of long duration, and a deep infiltration of the affected parts occurs, hemorrhages not infrequently make their appearance. These may be slight although frequent; occasionally, however, larger blood-vessels are encroached upon in the process of destruction, and dangerous, nay even fatal, hemorrhages may be the result. The septic forms which I have here described are more dangerous than the mild ones previously mentioned. Still, even in the latter bad results may ensue from a direct absorption into the blood of putrid substances and by the penetration of fetid gases to the lungs.

Occasionally, where the infiltration has been extensive, we meet with a condition that can only be considered as gangrene. In such cases we see collections of a grayish pulpy mass, which on falling off leaves a considerable loss of tissue, the further course of the disease being either favorable, or dangerous through absorption of septic material, or accompanied by local hemorrhages. When, after a time, health is completely restored, marked cicatrices are left behind. Such loss of tissue is generally seen in the tonsils only, but it may also be encountered in the soft palate. Its cicatrices on the soft palate are always a source of inconvenience, partly in swallowing, partly in speaking. Actual local perforation of the soft palate I have seen but five times in twenty-five years, sloughing without perforation very often.

The diphtheritic membrane not infrequently spreads from the pharynx to the neighboring organs. From the posterior aspect of the soft palate or pharynx the disease gradually ascends to the nasal cavities; this is particularly apt to occur when the uvula is the seat of extensive deposits, and by forced inspiration and deglutition its posterior surface becomes affected. In such cases the membrane which extends thence to the nasal cavities is very dense, and capable of narrowing the capacity of the nasal cavities anteriorly, and occasionally even to close them entirely; as a rule, however, several days elapse before the membrane assumes such a condition. Usually, when this form of nasal diphtheria is in its incipient stage, it is impossible to diagnosticate it; the most important sign thereof, besides a more nasal articulation and sometimes greater difficulty in deglutition, and the result of close ocular examination while the uvula is turned sideways or drawn forward, is a swelling of the deep facial glands at the angle of the lower jaw; when these swell rapidly it can be asserted positively that the nasal cavities have been invaded. There is little or no discharge from the nostrils under these circumstances.

The picture is a very different one, however, when the nose becomes primarily affected. This usually occurs only where an acute catarrh with but little secretion, not so often where a chronic catarrh, has preceded infection. When the secretion is thin and serous, the diphtheritic infection renders it no thicker, but makes it slightly flocculent, and it may become very profuse. This form is frequently attended with a disagreeable odor, equally unpleasant to the patient and to those around him. During the prevalence of an epidemic one must always be prepared to see an acute nasal catarrh or an influenza, or even a chronic nasal catarrh, become complicated with diphtheria or pass into it. Schuller reports the case of a five-weeks-old male child who, having had a nasal catarrh since birth, became affected with diphtheria of the nose. The glandular swelling of which I spoke above is a very important diagnostic, and likewise a decidedly unpleasant symptom, which becomes very marked inside of twenty-four hours; frequently a partial swelling remains long after the disappearance of the diphtheritic membrane. Such glands rarely suppurate or undergo a necrotic degeneration; sometimes they become permanently indurated. This induration and a chronic pharyngeal and nasal catarrh are very serious matters in many instances. Both of these conditions are starting-points for a number of acute or subacute attacks of diphtheria in the same person. It is they which constitute the liability of persons once affected to be taken sick again. Not only are they liable to be affected themselves, but they are a constant danger to all around them. Diphtheria, in a large family of children living in one of the best houses of the city, after having returned half a dozen times in the course of a year, disappeared instantaneously, not to return, when a seamstress living in an infected neighborhood and suffering from occasional sore throats was relieved of her daily work in the house. Oedematous swelling of the mucous membrane and submucous tissue is often observed for a long period to come; elongated uvulæ, enlarged tonsils, often date back to such an acute attack. Thus it is with the upper portion of the larynx about the posterior insertion of the vocal cords (see below); its large amount of loose submucous tissue is liable to swell considerably in acute attacks. Frequent spells of croupy cough and a certain degree of dyspnoea are often observed for years afterward. Though the cases of genuine cicatrization between the arytenoid cartilages, as described by Michael,10 be rare, with their result of permanent paresis of the thyroarytenoid interni muscles, when they do occur they are either obstinate or altogether incurable.

10 Deutsch. Arch. f. klin. Med., 1879, xxiv. p. 618.

Diphtheritic conjunctivitis occurs either primarily or as a complication of pharyngeal or nasal diphtheria. Fortunately, it is not of frequent occurrence; the cornea may become destroyed either by pressure through the considerable swelling of the eyelid or by diphtheritic keratitis. Usually the upper eyelid is the first to suffer; it is red, rigid, swollen. In the beginning the conjunctiva palpebræ is smooth, dry and pale, while that of the eye is chemosed; afterward diphtheritic deposits take place either in floccules or in solid masses. Knapp distinguishes between croup and diphtheria of the eyelid according to the facility or impossibility of removing the deposit. In favorable cases the membranes begin to macerate and the eyelids to soften after a few days. In those less favorable perforation of the cornea, prolapse of the iris, or total destruction of the eye take place.

The ear is but rarely the primary seat of diphtheria. A girl of three years died of laryngeal diphtheria on Sept. 6, 1882, after an illness of four days. A girl of seven years was removed from the house on Sept. 6th and returned on Sept. 8th. On the afternoon of the 10th an earring taken from the corpse was attached to the left ear of the sister, after having been washed with soap and water only. About noon on the 11th the lobe of the left ear reddened, on the 12th it exhibited a membrane and became swollen, and some glands enlarged in the neighborhood. On the right mastoid process the skin was not quite healthy, a vesicatory having been applied three weeks previously. This surface became diphtheritic on the 12th, without consecutive glandular swelling. On the 13th the membranes grew thicker; on the 14th the pharynx was also affected, and the physician called in.

Most diphtheritic affections of the ear, however, are secondary. In pharyngeal and nasal diphtheria the narrow orifice of the Eustachian tube is easily obstructed by either catarrhal swelling or diphtheritic deposit. The disease may invade the middle ear and the drum membrane with perforation, caries, and deafness following.

The descent of the diphtheritic process into the respiratory organs may give rise to various conditions. The membrane is not always found to pass uninterruptedly from the mucous membrane of the fauces into the larynx; not infrequently isolated diphtheritic spots are found in the pouches on either side of the attached extremity of the epiglottis, or on the epiglottis, or in the larynx. At such times the epiglottis is moderately swollen, its margins hard and reddened. Occasionally the redness is interrupted by small diphtheritic deposits, which may remain isolated for a considerable time, but generally coalesce so as to coat the edges of the epiglottis with a continuous membrane. As a rule, the upper surface of the epiglottis is not completely covered by membrane, while only now and then diphtheritic deposits are found on its under surface.