the face, with a tendency to crescentic arrangement. The eruption of chickenpox is at first papular and subsequently vesicular; it appears on the first or second day and is rather less than more abundant on the face than on the trunk. The catarrhal symptoms of measles are wanting in varicella. The temperature-course is not characteristic in varicella, as it is in measles.

Erysipelas.

What are the symptoms of erysipelas ?

Erysipelas is an acute, infectious disease, setting in suddenly with a chill, sometimes with nausea and vomiting, or with convulsions, followed by considerable elevation of temperature, and the appearance, usually at some part of the face, and in most instances near one or other ear, of an area of red, brawny induration. The redness progressively increases in extent, is definitely circumscribed by an elevated line of demarkation, and is attended with swelling.

The appetite is impaired. The tongue is coated.

The urine is usually albuminous, and often contains tube-casts. There is often some soreness of the throat, and in some cases the disease may extend through the nasal passages into the pharynx and larynx, causing grave complications, and, perhaps, fatal edema. Sometimes the disease begins in the throat.

Involvement of a cerebral sinus may occur, giving rise to severe symptoms and eventually causing death.

Usually, in the course of a week or ten days, the redness and swelling subside, desquamation sets in, and the temperature gradually reaches the normal.

In some cases, the disease displays a migratory tendency, (erysipelas migrans), continuing for a long period of time, and in turn appearing at various parts of the body. In children, erysipelas sometimes appears first in the neighborhood of the anus. The disease often attacks wounds.

What are the differential features between erysipelas and scarlatina?

Scarlatina is especially a disease of childhood. Erysipelas is more common in adults than in children.

The temperature is high in both, but the rapidity of the pulse is the more characteristic of scarlatina.

The rash of erysipelas is circumscribed in extent, limited in area, homogeneous in color; it usually appears upon the face, and presents a peculiar brawny induration, with well-defined borders; while the eruption of scarlatina is extensive in distribution and punctate in character.

An attack of scarlatina confers immunity from subsequent attacks; one attack of erysipelas rather predisposes to the occurrence of subsequent attacks.

Of the two, scarlet fever is the longer in duration.

How does erysipelas differ from simple erythema?

Simple erythema presents a diffuse redness, of transitory character, without febrile concomitants or sequelæ.

Erysipelas is a serious affection, with considerable elevation of temperature and characteristic rapidity of pulse. It lasts a week or more, is followed by desquamation, and is intimately related with nephritis.

How are facial erysipelas and herpes zoster of the forehead and face to be differentiated?

Facial erysipelas and herpes zoster of the forehead and face present a number of symptoms in common. That which distinguishes the latter, however, is that the eruption begins as a number of vesicles and does not extend beyond the middle line. The pain is much greater in herpes than in erysipelas. The constitutional symptoms are more profound in erysipelas than in herpes.

How are variola and erysipelas to be differentiated?

When variola is attended with a primary roseola, the disease may, for several days, simulate erysipelas. The redness of erysipelas, however, is distinctly circumscribed, although it may slowly spread, and is attended with brawny induration, while that of smallpox rapidly spreads from the face to the trunk and extremities. On the third or fourth day, if the disease is variola, papules appear, progressively passing through the

stages of vesicles and pustules. The eruption of erysipelas undergoes little change, unless large blebs form, until on about the fifth or seventh day, when it may subside with desquamation.

Dengue,

What are the symptoms of dengue or "break-bone fever?' Dengue is an exanthematous and arthritic disease of hot climates, occurring in epidemics, and having a period of incubation of about four days. It is characterized by severe pains in the muscles and joints, which may be stiff and swollen. The knees are especially prone to be affected, so that the gait presents a peculiar character. The disease may be gradual in onset, with anorexia, headache, vertigo, drowsiness, or it may set in suddenly with a chill, moderate elevation of temperature and the appearance of an erythematous rash. There are stiffness of the neck and pain along the spine and in the lumbar region. The fever reaches its acme within twenty-four hours. The temperature fluctuates, rising and falling, but in the course of two or three days subsides nearly or quite to the normal; the eruption disappears, though constitutional depression and more or less pain continue. As a rule, nausea and vomiting do not occur at this stage, though the tongue may be heavily coated, and there may be other symptoms of gastric irritability.

After an intermittence of from forty-eight to seventy-two hours or more, the fever returns and a new eruption appears, as a rule resembling the eruption of scarlatina. Sometimes the eruption is more like that of measles, or it may be urticarious or vesicular. It is attended with heat and itching. Nausea and vomiting are usually manifested with this renewal of the fever.

In the course of a few days, desquamation occurs; convalescence sets in, but is tardy and protracted; there is weakness and more or less rheumatoid muscular pain; lymphatic swellings in the neck, groin or axilla often appear during the febrile period or during convalescence. When the disease invades a community, few escape.

How does dengue differ from scarlatina with arthritic manifestations?

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In dengue the fever is not continuous and pursues a course different from that of scarlatina; the arthritic symptoms are of earlier occurrence, and the pain is of a characteristic nature, giving the name break-bone" fever. The eruption develops much later, and is sometimes quite different in appearance from that of scarlatina. The erythematous rash of the period of invasion is slight, inconstant and disappears without desquamation when the remission or intermission occurs. Throat-symptoms are not common.

In what respect does dengue differ from influenza?

Influenza is the graver disease; its symptoms are the more intense.

Catarrhal symptoms are frequent in influenza, înfrequent in dengue.

Eruptions are exceptional in influenza, the rule in dengue. Joint-pains are more decided in dengue. Hyperesthesia of the cutaneous surface is more common in influenza.

The course of dengue is interrupted by a remission. The course of influenza is usually though not invariably continuous to its termination.

Influenza is independent of climate. Dengue prevails only in certain localities. Convalescence is even more tedious and protracted from dengue than from influenza.

Diphtheria.

What are the symptoms of diphtheria?

Diphtheria is an acute, infectious disease affecting children especially, but adults as well, and characterized by septic fever with superficial coagulation-necrosis of mucous membranes, especially of those of the pharynx, larynx and nares.

The attack may begin insidiously, or set in suddenly with a chill, followed by considerable fever.

Pain in the throat in swallowing may or may not be complained of. The fauces will be seen to be livid, the tonsils usually swollen.

Soon, there appear, in greater or less extent and rapidly spreading over the tonsils, the half-arches, the uvula and the posterior wall of the pharynx, grayish or yellowish patches of false membrane, the forcible detachment of which is followed by bleeding. There are enlargement of the submaxillary and cervical glands and tumefaction of the soft tissues of the neck, externally.

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The constitutional disturbance becomes profound. uria is common. From the pharynx the inflammation and necrosis may extend to the larynx and to the nose, and to the difficulty of swallowing are added croupy cough, aphonia, difficulty of breathing and a nasal discharge. The diphtheritic process is sometimes primary in the nose, and may thus escape detection, unless careful examination be made. From the larynx the false membrane may invade the trachea and bronchi. Pneumonia may occur. The action of the heart becomes weak and often intermittent. Septicemia, heart-failure and suffocation from obstruction of the larynx or bronchi are the common causes of death.

The fatality of the disease varies in different epidemics. Even in times of grave epidemics, there are many mild cases that become foci of infection. Chronic diphtheria of the throat is not so rare as it is commonly considered to be and is likewise a focus of infection. Paralysis from peripheral neuritis or cerebral thrombosis may be a sequel.

The palsy of diphtheria may appear in the course of the disease, but it is more common after the acute attack is at an end. Adults are rather more prone to suffer than children. The most common manifestations are paralysis of the palate, permitting regurgitation of fluids and giving rise to nasal speech; paralysis of the ciliary muscle (cycloplegia), causing loss of power of accommodation; loss of knee-jerks. There may be more general palsy, with deranged sensation, ataxia and trophic changes.

How are diphtheria and scarlatina to be differentiated?

At the onset, the diseases may be indistinguishable. Both present the evidences of constitutional disturbance, with local