How Often?--As a rule, it attacks a person only once; yet there are recorded cases of well observed second and third attacks, but fortunately these are very rare. I once attended a family where they had it and claimed to have had it before, but very lightly. Incubation.--The vast majority of cases develop within three to five days after exposure. If eleven days elapse without the appearance of symptoms we may reasonably expect that the danger is past, at least in the great majority of cases exposed. Contagiousness.--There is danger of catching the disease during the stages of incubation, eruption and scaling. It is most contagious in the last two stages. Onset.--Sometimes the onset is sudden; there may be a convulsion, preceded by a sharp rise in the temperature. An examination in such cases may reveal a marked sore throat or a membranous deposit on the tonsils preceding the eruption, and nothing more. A chill followed by fever and vomiting ushers in a large number of cases. These may be mild or severe. The severity of these symptoms usually indicates the gravity of the attack. Rash.--The rash or eruption appears from twelve to thirty-six hours after the onset, usually on the second day, and looks like a very severe heat rash, but is finer and thicker. It consists of a very finely pointed rose-colored rash. In mild cases it is hardly noticeable. Usually it first appears on the upper part of the chest around the collar bones, spreads over the chest and around upon the back. Also it is now seen on the neck, beneath the jaw, behind the ears and on the temples, thence spreads over the body. There is a paleness about the mouth and wings of the nose, while the cheeks are flushed with a flame-like redness. There is much itching if the rash is severe. It attains the full development at the end of two or three days, and then gradually declines. In some cases the rash is seen only twenty-four hours. Fever.--The fever rises rapidly in the first few hours to 104 or 105-8/10 degrees. It remains high except in the morning, until the eruption reaches its full development and falls with the fading eruption, and in uncomplicated and typical cases, within six days becomes normal. [INFECTIOUS DISEASES 169] Sore Throat.--This we find on the pillars of the fauces, uvula, tonsils, and pharynx, reddened and inflamed. Sometimes it is very severe, and a membrane comes on one or both tonsils and pillars of the fauces. There is, generally a severe sore throat, and this makes swallowing difficult. Tongue.--The tongue is covered with a coating at the onset, and may present a slightly reddened appearance at the borders and tip. The papillae are prominent and covered and look like a strawberry sometimes, or like the tongue of a cat. In fatal poisonous cases it becomes dry and cracked.