If the vaccination "takes," it passes through several stages. On the third day following vaccination a red pimple forms at the point of introduction of the matter, which is surrounded by a circle of redness. Some little fever may occur. On the fifth day a blister or pimple containing clear fluid with a depressed center is seen, and a certain amount of hard swelling, itchiness, and pain is present about the vaccination. A sore lump (gland) is often felt under the arm. The full development is reached by the eighth day, when the pimple is full and rounded and contains "matter," and is surrounded by a large area of redness. From the eleventh day the vaccination sore dries, and a brown scab forms over it about the end of the fourteenth day, and the redness and swelling gradually depart. At the end of about three weeks the scab drops off, leaving a pitted scar or mark. Not infrequently the vaccination results in a very slight pimple and redness, which passes through the various stages described, in a week or ten days, in which case the vaccination should be repeated. Unless the vaccination follows very closely the course described, it cannot be regarded as successful, although after the first one or two vaccinations the result is often not so severe, and the time of completion of the various stages somewhat shortened. Rarely an eruption, resembling that at the vaccination site, appears on the vaccinated limb and even becomes general upon the body, due to urticaria or to inoculation, through scratching.