Vaccination, vak'se na' shun, inoculation with the cowpox--a disease akin to, but much less severe than, smallpox--in order to prevent a person from catching the latter, or to make the attack much less severe. The practice of vaccination was introduced by Jenner, and it soon came into common use, instead of the common inoculation of one person from the sores of another. The usual method in vaccination is to make, upon the upper part of the arm, a few scratches across one another, with a clean lancet point. The virus from cowpox eruptions is then rubbed on the skin where the scratches have been made. If the vaccination proves successful, a small inflamed sore appears about the third day and increases in size until the tenth day. On the eighth day the constitutional effects manifest themselves by a slight pain in the part, headache, shivering and loss of appetite. These subside spontaneously in one or two days. Afterward the fluid in the pustule dries up, and a scab forms, which disappears about the twentieth day, leaving a scar in the skin. Few things have been more definitely proved in medicine than that vaccination is a preventive of smallpox. To secure perfect immunity, repeated vaccinations at intervals of several years are necessary in most cases. There is no danger in vaccination if pure virus is used and if the wound is kept free from infection. The wise plan is to have the vaccination made by a good physician, who will treat the wound properly and prevent any injurious results.