The Bacillus tuberculosis is grown on glycerine-serum and the resulting cultures scraped off and heated to 60° C. to kill the bacteria, dried in vacuo and triturated. The resulting mass is emulsified and centrifuged, the upper layer rejected and the lower again dried, triturated and again emulsified and centrifuged, the upper layer is set aside and the residue subjected to the same process. The resulting layers are preserved with glycerine and standardised to contain 10 milligrammes of solids, in 1 c.c. It may be used thus as a liquid or may be dried. The dose is calculated as 1/6,000-1/1,000 mgms. of solid substance.