or blister which may be plainly seen on the fifth or sixth day. On
the eighth day the blister (vesicle) is, or should be, plump, round,
translucent, pearly white, with a clearly marked edge and a depression in
the center; the skin around it for about half an inch is red and swollen.
This vesicle and the red, inflamed circle about it (called the areola) are
the two points which prove the vaccination to be successful. A rash, and
even a vesicular eruption, sometimes comes on the child's body about the
eighth day, and lasts about a week; he may be feverish, or may remain
quite well. The arm may be red and swollen down as far as the elbow, and
in the adult there will usually be a tender or swollen gland in the
arm-pit, and some disturbance of sleep for several nights. The vesicle
dries up in a few days more, and a crust forms which becomes of a brownish
mahogany color, and falls off from the twentieth to the twenty-fifth day.
In some cases the several appearances described above may be delayed a day
or two. The crust or scab will leave a well-marked, permanent scar.

[INFECTIOUS DISEASES 207]

What to do during and after Vaccination.--Do nothing to irritate the
eruption, do not pull the scab off, when it drops off throw it in the
fire. When the eruption is at its height show it to the doctor who
performed the vaccination. If it is satisfactory, ask him for a
certificate stating when and by whom you were vaccinated, whether with
bovine or humanized lymph, in how many places and with what result at each
place. When the arm is healed, if the vaccination did not work well, be
vaccinated again as soon as possible, and in the best manner possible.
This will be a test to the protection secured by the former vaccination,
and will itself afford increased protection. Do not be satisfied with less
than four genuine vaccine scars, or with four if it is possible to secure
more than four. This vaccination a second or third time in close
succession is believed to be hardly less important than vaccination the
first time, and hardly less valuable as a protection against smallpox.
Without doubt many persons are living in a false sense of security from
smallpox because at some time in their lives they have had a little sore
on their arm caused by a supposed or real vaccination, or because an
imperfect vaccination failed to work, or because they were successfully
vaccinated, or had the varioloid, or the unmodified smallpox many years
ago. Unt