This small pamphlet tells of a new product prepared by the digestion of tubercle bacilli by pancreatic extract in the hope of finding something which would be of more benefit than tuberculin in producing immunity to tuberculosis and in the treatment of the disease. The details of preparation and the chemistry are given in full. Experiments with guinea-pigs, mice and rabbits are reported. Bazilin was found to be less toxic than old tuberculin, and the authors believe that there is some evidence that it has a protective action. The experiments were too few, however, to warrant definite conclusions.