Symptoms.-Incubation may be short, the attack developing a few hours after exposure. Ordinarily the period is from five to seven days, during which time there are no symptoms. The disease begins abruptly with a chill, followed by a rapid rise of temperature, running to 103° to 107° F. within twenty-four hours. There are severe and distressing pains in the head, back, and bones. Prostration. is well marked at the onset, the patient taking to his bed at once. The pulse is full and varies between 110 and 130. There is usually nausea; there may be severe vomiting, and in some cases vomiting of blood. In severe cases there may be delirium. Convulsions may be the first symptom in young subjects.

The liver and spleen are regularly enlarged and tender. Blood-examination shows the spirilla in active movement among the red blood-cells. Jaundice may be present in the attack or in any of the relapses. It belongs to the severer forms of the disease.

There is no characteristic eruption, but in certain cases there may appear small reddish spots somewhat resembling the eruption of typhus fever, or there may be petechial spots. The urine contains a slight amount of albumin and casts from parenchymatous degeneration.

While the symptoms are at their height the paroxysm suddenly ceases, the temperature suddenly falling by crisis, and the patient is left weak but convalescent. This remarkable crisis usually occurs between the fifth and the seventh day, although it may occur as early as the third or as late. as the tenth day. This abrupt crisis, which is always a time of danger, may be accompanied by profuse sweating or exhausting diarrhoea. In some cases there may be collapse, or hemorrhages from the stomach, the intestines, or the kidneys.

After such an attack the patient may pass on to recovery,

but in the majority of cases, after an interval of about seven days (the limit is from five to twenty days), the patient is again suddenly seized with a repetition of all the symptoms of the first attack, the spirilla again becoming present in the blood. This second attack usually is less prolonged than the first, lasting about three days, although it may last only one day or be prolonged for a week. This attack terminates by crisis as does the first. The patient may now pass on to complete recovery, or there may be a series of these relapses (up to five or six), these subsequent attacks becoming shorter and less severe.

Complications.-There may be hypostatic congestion of the lungs or broncho-pneumonia. Laryngitis and oedema of the glottis may occur. There may be rupture of the spleen with internal hemorrhage and peritonitis. Nephritis is of rare occurrence. In severe cases there may be hemorrhages from the stomach, the intestines, or the kidneys.

Convalescence is apt to be slow and tedious, especially if there has been a series of relapses. There may be paralyses of groups of muscles from post-febrile neuritis. There may be ophthalmia with loss of sight.

The prognosis is good. The mortality is from 2 to 4 per cent.

Treatment. There is no specific treatment. Cases are to be isolated thoroughly, and clothing, etc. disinfected, to prevent the spread of the disease. The treatment is on general principles. It is especially important that the patient should be well watched at the time of crisis for indications of heart failure. The diarrhoea which often occurs at this time should be treated promptly. After the crisis the patient should be kept in bed for at least a week and on fluid food.

SMALL-POX.

Definition and Synonym.-Small-pox is an acute infectious, contagious disease with marked constitutional symptoms and a characteristic eruption. Synonym: Variola.

Etiology. This disease was known to the ancients and was fully described by the older writers. Formerly it occurred in devastating plagues, but since the discovery of vaccination it has become less and less frequent, so that cases of true small-pox are but rarely seen. With universal vaccination the disease bids fair to become extinct.

Small-pox is actively contagious throughout its entire course. The contagion, which is conveyed by personal contact or by the medium of a third person, emanates from the bodies of the sick and the dead, floats in the air, and can remain in bedding, clothes, cabs, and rooms for months and years without losing its virulent properties. It is inoculable by the contents of the vesicles and pustules and by the blood of the sick, and is most actively conveyed by the scales and crusts thrown off by the patients; these scales float in the air as a fine dust, and in this way may be carried long distances.

The exact nature of the contagion has never definitely been determined. Micro-organisms have been found in the contents of the vesicles and pustules, but these micro-organisms are common to all suppurative processes.

Susceptibility to the disease is almost universal except among those protected by vaccination or by a previous attack. No age is exempt, the disease even attacking the foetus in utero. Negroes are more susceptible than other races, though this may be due to their neglect of vaccination. Vaccination properly performed procures immunity, as does a previous attack, although in rare cases the immunity may not extend beyond a term of years (five to fifteen).