“…Amberg (1910), using linear scarification, had thirteen positives from 131 casual patients; four of the thirteen had no previous history of ringworm. Repeating this investigation, Rosen, Peck, and Sobel (1931) intradermally tested 102 dermatological patients-seventytwo of them with some pedal skin lesion-and found a positive reaction in sixty-seven. There were nine proved cases of tinea pedis in this series, and eight of them reacted strongly.…”