Studies on the Tuberculin Production - (3) Studies on the Change of Tuberculin Reactivity when Repeated Tuberculin Injection

Tuberculin에 관한 연구(硏究) - (3) Tuberculin 반응(反應)을 반복(反復)할 때 일어나는 변화(變化)에 관한 관찰(觀察)

The author prepared a tuberculin sample using synthetic medium for the test material in this experiment. For the test animals, guinea pigs, healthy calf sensitized with heat killed tubercle bacilli, naturally infected dairy cattle, goat, and calf were used. A reduced reactivity to tuberculin was observed when the second tuberculin test was done within 28 days after the first. The results obtained are summarized as follows. 1. The experimental HCSM tuberculin was shown the similar activities as the control products of standard tuberculin. 2. The potency of the experimental tuberculin preserved at $5^{\circ}C$ in refrigerator maintained the activity for three years. 3. By the intradermal test, the experimental tuberculin was proved to be specific to detect tuberculous dairy cattles and goats. 4. The appearance of skin reaction to tuberculin in naturally infected dairy cattles, goat and beef cattles was soft and diffuse swellings or circumscribed swellings accompanied by induration. 5. In the case of observing tuberculous dairy cattles, goats and beef cattles, as the criterion of the reaction to the caudal fold test, results were taken as positive when findings are either hard and circumscribed or soft and diffuse swellings of 3 mm at least in size. 6. The acid fast organisms isolated from tuberculin positive animals were identified mostly as M. tuberculosis var. bovis. 7. When the tuberculin test was repeated in the tuberculin positive animals, the reactivity decreased rapidly, lasting 4 weeks at least.