Alexander Schneider, a renowned violinist and conductor, died last Tuesday. He was 84 and had suffered from heart disease.Schneider was a member for more than 30 years of one of the century’s most acclaimed quartets, the Budapest String Quartet. He was also a frequent guest conductor with orchestras in the United States and Europe. In 1961, he performed at a historic White House concert for President Kennedy with Mieczyslaw Horszowski and Pablo Casals. As a solo artist, chamber musician and conductor, Schneider made more than 100 recordings and performed with some of the greatest musicians of the century, including Casals, Rudolf Serkin and Isaac Stern. In 1988, he was honored by the Kennedy Center in Washington for lifetime achievement in classical music.