“…So, we spent a few years without any positive results. However, from 1967 to 1975, wc made slow but steady steps and detected SO (17), CIO (18,19), NS (20), BrO (2I), NCO (22,23), and SF (24). I certainly admit that our progress was very slow, but I must also say that the detection of free radicals was extremely difficult at that time.…”