“…In an earlier communication a technique was described for detection of isoniazid-susceptible tubercle bacilli as a routine in diagnostic laboratories (Tirunarayanan and Vischer, 1957a, b;Vischer and Tirunarayanan, 1957). Whereas no instance of an exception was observed by the writers, and good correlation was demonstrated by several other investigators, there arose certain doubt that led to difficulty in interpretation.…”