appears on mucous membranes, it is modified by the heat, moisture, and friction of the parts, and, instead of pustules being formed, the vesicles become macerated and form ulcers, more or less deep, which may become confluent.

As the eruption appears the temperature suddenly falls -not, however, quite to the normal, but still remaining a little high. The constitutional symptoms remit in their severity, especially the headache and backache, so that the patient feels quite comfortable, and often is able to leave the house and to apply for treatment at a hospital or a dispensary.

The amelioration of the symptoms continues until the pustular stage is reached, when there is developed a rise of temperature to 101° to 105° F. with a return of all the symptoms. This fever, which is termed the secondary or suppurative fever, is often remittent. During this stage there may be active delirium, so that the patient may do himself or his attendants bodily injury. The distress during this period from the itching, tension, and burning of the skin is almost unbearable. The patient is disfigured and often is hardly recognizable.

The period of secondary fever lasts for from three to eight days, and then as desiccation is established the temperature gradually falls and convalescence is begun. The hair frequently falls out, and in some cases does not grow again.

2. The Confluent Form.-Here the typical symptoms are present in the most complete development. The stage of invasion is short, lasting but two days as a rule. It is also severe, the fever being high, with pronounced headache and frequently with active delirium. There is no period of cessation with the appearance of the eruption, although the symptoms may remit slightly in their severity.

The eruption is profuse, the pustules becoming confluent,

lages, resulting in stenosis, necessitating intubation or tracheotomy.

Broncho-pneumonia is a common complication, especially in the severer cases. There may be pleurisy. Nephritis is rare, although the urine usually contains a small amount of albumin. There may be orchitis. During the suppurative stage there may be developed septicæmia or pyæmia or arthritis. In rare cases a disseminated myelitis has been observed. Convalescence may be interrupted by boils, by gangrene of the skin, or by erysipelas. Ulceration of the cornea is but rarely seen. During convalescence there may be a post-febrile insanity or paralyses from peripheral neuritis.

Prognosis. The prognosis depends upon the degree of protection afforded the patient by vaccination. Varioloid is very seldom fatal in those protected by vaccination, while in those totally unprotected the mortality ranges from 30 to 40 per cent. The prognosis depends also upon the severity of the attack, the hemorrhagic and malignant forms being almost certainly fatal, the confluent form being very dangerous, while the discrete form affords a large percentage of recoveries. It depends also upon the age and the condition of the patient, being most fatal in children and old people, in the debilitated, and in drunkards. The prognosis is affected also by the presence of compli

cations.

Treatment. If vaccination and revaccination could be performed thoroughly, variola would become extinct. After exposure to variola, revaccination should be resorted to, and it is probable that vaccination even in the earliest stages of the disease itself, if done before the fourth day, greatly mod ifies its severity.

Patients with variola should properly be treated in contagious hospitals, as few private houses afford sufficient

means for thorough isolation and disinfection. When this cannot be done, quarantine should be conducted on the strictest principles, and should be continued until the skin. and the hair are absolutely free from crusts and scales. All articles that come in contact with the patient should be sterilized or be destroyed.

The room should be kept moderately cool and well ventilated. Patients are rendered worse by being kept too hot. The occurrence of mania should be anticipated by careful watching and by having the windows barred. The diet should be of milk.

The fever is best treated on hydropathic principles; the headache and backache are to be combated by opium or phenacetine. Sleep may be procured by sulphonal, chloralamide, or codeia.

The patient should, if possible, be prevented from scratching. Great care should be exercised in the strictest cleansing of the eyes and in preventing them from being infected by their being rubbed with pus-stained hands.

cleansing a saturated solution of boric acid is to be preferred.

As the extent of the pitting depends entirely upon the depth of the pustules, there is no method of treatment known by which pitting can be prevented. It seems, however, that the intensity of the pustules is modified by excluding the light and by keeping them covered with strips of gauze constantly wet with weak solutions of bichloride or of carbolic acid. This application also relieves the pain and itching. Isolated pustules may be painted twice a day with 10 per cent. carbolic acid in alcohol. When crusts form they are to be softened by applications of lard or of vaseline to prevent them from floating in the air and thus carrying the infection. The other symptoms and complications should be treated on general principles.

VACCINIA; VACCINATION.

Vaccination was first performed in 1798 by Jenner, and its value is now universally acknowledged. The vaccine may be procured by means of the scabs of patients vaccinated (humanized virus), or be taken direct from the calf (bovine virus). If the humanized virus be used, it is of the utmost importance that it be taken from a healthy subject free from every trace of syphilitic and tubercular taint. As a rule, bovine virus obtained fresh from reliable sources should be used.

In a primary vaccination there appears in from twentyfour to thirty-six hours a papule which on the fifth or sixth day becomes an umbilicated vesicle surrounded by an indurated inflammatory zone. This papule on the eighth or ninth day changes to a pustule, which dries up, and the brownish scab resulting falls off on the twentieth to the twenty-fifth day, leaving the characteristic scar. In patients who have already been vaccinated successfully there may be either no result, or an irregular atypical vesicle, or a local ulceration on an inflammatory base.

About the third day of vaccination there begins a moderate fever, often preceded by chilly feelings, with malaise, restlessness, and irritability, these symptoms being especially marked in children. These symptoms increase moderately until pustulation is completed; then they subside. The neighboring lymphatic glands become swollen, painful, and tender.

The protection afforded varies with the completeness of the vaccination and with the time that has elapsed since it was last performed. Every baby should be vaccinated, preferably between the second and third months, and thereafter every seven years-oftener, however, if exposed to small-pox or during an epidemic. Should, under these

latter circumstances, a revaccination be unsuccessful, it

should be repeated.

Complications of vaccination are due either to lack of cleanliness or to impure virus employed, and should not occur if proper precautions be taken. There may be sloughing ulcers, gangrene of the skin, or erysipelas. Septicæmia may develop in neglected cases. Impetigo contagiosa has been known to result. The patient may be inoculated with syphilis from humanized virus taken from diseased patients, the double infection resulting in the primary lesion at the site of inoculation. There may be observed vesicles about the inoculation, or a general eruption of vesicles from absorption of the virus.

VARICELLA.

Definition and Synonym.-Varicella is a contagious disease especially of childhood, and is characterized by a vesicular eruption. Synonym: Chicken-pox.

Etiology. Varicella occurs in sporadic, endemic, and epidemic forms. It is contagious throughout its course, but the contagious principle is of a low grade of intensity. It is almost exclusively a disease of children, but it may occur in young adults. One attack does not afford absolute immunity from subsequent attacks.

The exact virus has not been determined definitely. There is no connection, immediate or remote, between this disease and variola or varioloid.

Symptoms. The period of incubation is from eight to seventeen days, and it is unattended by symptoms. The invasion is marked by chilly feelings in some patients and by feverishness, the temperature rarely being higher than 102° F. except in very young children, in whom a fever of 104° F. is not unusual Convulsions are rare at the onset. There is apt to be vomiting, and the child complains of lassitude