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 and others had found previously, inoculation was able to confer resistance to arguments that were not specifically mentioned in the inoculation message. Compton and Ivanov (2013) offer a comprehensive review of political inoculation scholarship and outline new directions for future work. Sample studies include: Pfau and some of his colleagues examined inoculation through the use of direct mail during the 1988 presidential campaign. The researchers were specifically interested in comparing inoculation and post hoc refutation. Post hoc refutation is another form of building resistance to arguments, however, instead of building resistance prior to future arguments, like inoculation, it attempts to