BCG vaccine
In 1919, he was assigned to the laboratory of tuberculosis headed by Albert Calmette (1863–1933) at the Pasteur Institute in Paris. Here he took part in research of Bacillus Calmette-Guérin (BCG vaccine). With microbiologist Alfred Boquet (1879–1947) he developed "antigene méthylique" (methyl antigen) for treatment of tuberculosis.