The period of invasion lasts for forty-eight hours. During all this time the initial symptoms persist and the temperature continues to rise. . The pyrexia is not always great at this stage. A boy, aged eleven years, a patient in the Fast London Childrens' Hospital, suffering from heart disease and pleurisy, who had not been previously feverish, was found one morning to have a temperature of 101.6°. The next morning it was 99°, and in the evening 102°. On the following morning (the third day) the thermometer marked 102.2°, and the eruption appeared. In many cases, however, the pyrexia is greater, and the temperature may reach or higher. In the case of the little girl before referred to it was on the morning of the second day. Occasionally during this stage a roseo lous eruption, very like the rash of scarlatina, appears upon the skin, This is most common in cases of modified small-pox. It is right to say that the symptoms of the pre-eruptive stage are not always seen in this marked form. Dr. Twining of the Homerton Fever Hospital informs me that of the children who are admitted into that institution suffering from variola, many have complained merely of malaise, headache, or sickness ; and in not a few cases the first symptom noticed was the rash of the disease.
The -eruptive stage begins on the third day. In exceptional cases usually those of a malignant character—the rash may appear on the second day. Occasionally it does not show itself until the fourth. These excep tions are found in all the eruptive fevers. The special small-pox eruption begins as small red papules scattered more or less thickly over the surface. They are first noticed on the chin, nose, or forehead, and then quickly spread to the whole face. They are next seen on the wrists, and in the course of the following twenty-four or forty-eight hours spread gradually to the chest, the arms, the trunk, and the lower limbs. The spots are not sprinkled irregularly over the surface, but may be noticed to group them selves in threes and fives, often arranged in a semicircle. Sometimes when two of these crescents come together, they may by their junction complete the circle. The spots are set more thickly on the face than on the body, and as they appear earliest in this situation, they run through all their stages, and scab earlier here than on the trunk and limbs. The papule is hard, and gives to the finger the sensation. of a small shot em bedded in the skin. All are not, however, of equal firmness. Some have much more of a shotty character than others. Between the papules the skin is of normal colour and appearance ; but if the spots are set very closely together, there may be a general redness and granular look of the face without any intervening normal tint of the skin being visible.
At the same time that the papules appear on the skin, spots may be also seen, if looked for, on the inside of the cheeks and lips, on the inside of the nose, and sometimes even on the conjunctives. At first, as they
cause little discomfort, these are scarcely complained of ; but after a day or two they produce salivation, and pain in swallowing, and, if the air passages are similarly affected, hoarseness and cough. There is also some snuffling, and the eyes are red and watery. Later, when the rash is ap pearing on the lower limbs, the mucous membrane of the vagina, or urethra and prepuce, also become the seat of eruption.
The changes which occur in the rash are as follows : The papule en larges, becoming a flat-topped nodule, and in the course of the second or third day (fifth or sixth of the disease) changes into a vesicle. This change takes place, as.has been said, earlier on the face than on the body or limbs ; and, indeed, while the papules are coming out on the lower extremities, those on the face are already changing into vesicles. The vesicle is broad, flat-topped, and umbilicated. Its contents are opaque, and at first whitish in colour ; but by the sixth day (eighth of the disease) have become distinctly purulent, a deep red areola has formed round the pock, and the subjacent skin is swollen by inflammatory effusion. The spot is now a pustule seated on a thickened base. From the eighth to the eleventh clay the pock enlarges ; and the union of neighbouring areolm and the thickened bases of the pustules produces a general redness and swelling which completely obliterates all distinctive character in the feat ures of the patient, and causes a distressing tension and smarting irrita tion of the skin which is greatly complained of. There may be also extreme tenderness, so that the slightest touch is painful. The eyes are often closed by the swelling, and the lids are glued together by the vitiated secretions from the Meibomian glands ; the nose is stopped up ; the secretion of saliva is profuse ; and swallowing is very difficult and painful. The voice, too, is hoarse and the cough distressing. Often the eyes are inflamed, painful, and very sensitive to light. The process of maturing of the pustules (stage of maturation) lasts from the sixth to the ninth day (eighth to the eleventh of the disease) on the face ; on the lower limbs it begins and ends a day or two later. Consequently, the vaginal and urethral rashes and the distress they produce are at their height when the faucial and laryngeal mucous membranes have begun to improve. On these and the other mucous surfaces the eruption does not pass beyond the vesicular stage, but is accompanied by considerable redness and swelling of the membrane. While the pustules are maturing on the skin, the suppurat ing spots give out a peculiar and unpleasant odor, which is, however, char acteristic of the disease.