BCG vaccine fine powder. Sometimes the powder is sealed with vacuum in a glass ampoule. Such a glass ampoule has to be opened slowly to prevent the airflow from blowing out the powder. Then the powder has to be diluted with saline water before injecting. The history of BCG is tied to that of smallpox. Jean Antoine Villemin first recognized bovine tuberculosis in 1854 and transmitted it, and Robert Koch first distinguished "Mycobacterium bovis" from "Mycobacterium tuberculosis". Following the success of vaccination in preventing smallpox, established during the 18th century, scientists thought to find a corollary in tuberculosis by drawing a parallel
Inoculation theory defensive, but weak enough to not actually change those preexisting ideas. This will hopefully make the receiver actively defensive and allow them to create arguments in favor of their preexisting thoughts. The more active the receiver becomes in his or her defense the more it will strengthen their own attitudes, beliefs, or opinions (McGuire, 1964). There are four basic key components to successful inoculation: threat, refutational preemption, delay, and involvement. The first is threat, which provides motivation to protect one's attitudes or beliefs (Pfau, 1997a). Threat is a product of the presence of counterarguments in an inoculation message and/or an