VENZKE SAYS VICTORIES ARE RESULTDROPPINGOLYMPIC MENTORNEW YORK — (INS) — Gene Venzke attributes hi* phenomenal comeback, this winter to the fact that he had discarded Lawson Robertson, veteran University of Pennsylvania and Olympic coach, as 'his mentor.Gene grinned 'happily at ahoard of well-wishers who hadcome to 'Congratulate. Mm on his 4:10.2 Baxter mile victory over' Glenn Cunningham, the first time he had ever. won a mile test and beaten his Kansas nemesis in the■same race.When he entered Pennsylvania, and came under Robertson’s direction for the first time.. i 'The veteran coach, who was .in. chargeof Uncle 'Sam’s Olympians at Los .Angeles and who Is expected to handle them again in Berlin, had Gene Shorten his stride,Venzke fizzled out as soon as he changed his style,This winter, he decided to sidetrack Robertson, to let Bill Morris: Ms negro trainer, a disciple of Sweeney’s, 'handle him instead. And. the improvement was noted immedlately. He came in ahead of Cunningham in, the Wana-maker mile, beat Joe Siangan, his conquerer in the Mill rose feature, at Boston, and. .achieved the goal he had. been striving for four years when he led the Kansan- to the tape m the, Baxter mile.i