BCG vaccine bacilli that seemed less virulent, and changed the course of their research to see if repeated subculturing would produce a strain that was attenuated enough to be considered for use as a vaccine. The BCG strain was isolated after subculturing 239 times during 13 years from virulent strain on glycerine potato medium. The research continued throughout World War I until 1919, when the now avirulent bacilli were unable to cause tuberculosis disease in research animals. Calmette and Guerin transferred to the Paris Pasteur Institute in 1919. The BCG vaccine was first used in humans in 1921. Public acceptance was slow,
Inoculation needle hand immobile. In slant culture transfer, the inoculation needle will be first treated with the aseptic technique by flaming. The slant culture cap is then removed and secured using the needle hand. Flaming the open end of the slant culture will prevent contamination and the formation of aerosols. Transfer happens once the tip of the inoculation needle comes into contact with the agar surface of the slant culture. The inoculation needle should not move in the process. The agar slant culture will be moved up to the needle to prevent jostling of the needle. Once the transfer is complete from