For 30 years Samuel P. Perry, Jr., has spent his days and nights tutoring boys and girls in all subjects, preparing them for college. Almost any late afternoon you can see this quiet whirlwind of a Black man rushing back and forth among a half dozen Black students in Bates Hall, the huge research/reading room of the Boston Public Library. On Saturdays he tutors at the Dudley Branch Library. More than 600 students have passed through his tutelage - seven have become doctors, five are engineers, and three have MBA's. His students have gone to Vassar, Harvard, MIT, and Dartmouth.