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 to back that idea up. There are also scholars on the other side who suggest that too much of a delay lessens the strengthening effect of inoculation. With this being said, it has been revealed that the effect of inoculation can still be significant weeks or even months after initial introduction or the treatment showing that it does produce somewhat long-lasting effects (Banas & Rains, 2010). Involvement is the final element of the inoculation process. Pfau, et al. (1997a) defined involvement as "the importance or salience of an attitude object for a receiver" and is “among the most important and