[Detection of tubercular infection after BCG vaccination]

The author has followed several groups of children over a period of many years and evidenced the general decrease of the level of tuberculin reactivity. The implications are discussed, of the B.C.G. vaccination on the tuberculous allergy and the possibility to differentiate post-vaccinal allergy with the aid of skin testing, using 2 and 10 PPD units. The importance is stressed, of the vaccinal scar as an indication of a good immune reactivity, and thus of protection against contamination with virulent tuberculous baccili. The time is foreseen, when systematic vaccination with B.C.G. will reduce to such a significant degree the number of cases of tuberculosis in children that differential diagnosis on the basis of tuberculin allergy will not be necessary.