The New Student's Reference Work/Vaccination

Vaccination (văk′sī-nā′shŭn) is the process by which the disease termed vaccinia or cowpox, from the Latin word vacca, a cow, is introduced into the human system to protect it against the attack of the more severe disease of smallpox. In his Inquiry into the Causes and Effects of the Variolœ Vaccinœ Jenner, the discoverer of this remarkable remedy, establishes the following facts: (1) That this disease when communicated to man is a sure protection from smallpox; (2) that the cowpox alone, and not other eruptions affecting the cow, which might be confounded with it, has this power of protection; (3) that the cowpox may be communicated at will from the cow to man by the hand of the surgeon; and (4) that the cowpox once ingrafted on the human subject may be transferred from person to person, giving each one the same immunity from smallpox as was enjoyed by the person infected directly from the cow. See Jenner.