But Don't Hold Your Breath

By EMILY MITCHELL

"A scientist should change his field about every ten years," says Baron Manfred von Ardenne. A man of his word, he has worked over the years in physics, radio electronics and microbiology, and even helped Stalin build an atom bomb. As East Germany's best-known scientist, Von Ardenne, 83, heads a private lab in Dresden. His latest project is one to make skeptics gasp in disbelief. An "oxygen multistep therapy" -- which includes inhaling pure oxygen while exercising -- it is being touted as both a cure for cancer and a fountain of youth. He claims good results, though the final proof may be up in the air.