A skin test to determine whether or not an individual is immune to tuberculosis, carried out prior to vaccination. A spring-loaded gun mounted with very short needles produces a circle of six punctures in the forearm through which tuberculin is introduced. If the test is positive a reaction causes the skin to become red and raised, indicating that the individual is immune. If the test is negative a vaccine (BCG) should be given. F. R. G. Heaf (20th century), British physician
Subjects: Medicine and Health.